JPH0945872A - Dielectric thin film element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the surface of a lower electrode free from abnormal deposit and concentration of an electric field so as to improve a dielectric thin film element in dielectric strength, fatigue resistance, and permittivity by a method wherein a lower electrode is formed of Pt which contains at least one out of elements Rh, Ru, Os, and Ir. SOLUTION: A lower electrode 54 of Pt which contains, at least, one out of elements Rh, Ru, Os, and Ir is formed on a board 51. Moreover, a high dielectric or a ferroelectric film 55 and an upper electrode 56 are formed thereon. No hillock is deposited on the surface of the lower electrode 54 even if the device of this constitution is subjected to a thermal treatment carried at a temperature of 600 deg.C or above, so that the surface of the lower electrode 54 is kept flat, and the growth of nucleuses takes place well at the heat treatment of the high dielectric or the ferroelectric film 55, so that defects are prevernted from being generated. Abnormal deposits such as hillocks are not present on the surface of the lower electrode 54, so that an electric field is restrained from concentrating locally when a voltage is applied between the electrodes 54 and 56, and the device of this constitution can be improved in dielectric strength and fatigue resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric thin film element such as a memory device having a high ferroelectric film, a thin film capacitor device, an electro-optical device, and a thin film sensor.

[0002]

2. Description of the Related Art FIG. 9 is a sectional view of a general dielectric thin film element having a structure in which a high and a ferroelectric film is sandwiched between a lower electrode and an upper electrode. Reference numeral 91 in the figure is a silicon substrate,
On this substrate 91, an insulating film 92 serving as a base of the dielectric thin film element is formed.
Are formed. Here, the insulating film 92 is, for example, 0.5 to 1 μm SiO ₂ formed by thermal oxidation of the substrate 91.
It is a membrane.

A dielectric thin film element including a lower electrode 93, a high ferroelectric film 94 and an upper electrode 95 is formed on the substrate 91 with an insulating film 92 interposed therebetween. Here, the lower electrode 93
Is formed by sputtering Pt, which is stable against high temperature heat treatment, and has a thickness of 0.1 to 0.5 μm. The high and ferroelectric film 94 is made of, for example, Pb (TiZr).
O ₃ (PZT), PbTiO ₃ , BaTiO ₃ , SrT
iO ₃ , Ba (SrTi) O ₃ (BST), (PbL
a) TiO ₃ (PLT), Bi layered oxide or the like is formed by sol-gel method, CVD, sputtering to 0.2 to 0.5 μm and sintered at a temperature of about 600 ° C. The upper electrode 95 is made of Pt which is stable against high temperature heat treatment.
Is formed by sputtering and has a thickness of 0.2
０．５0.5 μm.

Further, as an upper electrode and a lower electrode of the dielectric thin film element shown in FIG. 9, an alloy of Pt and Pd is used in JP-A-4-349657. As a result, it is said that the formation of a silicon oxide film at the interface between the upper electrode or the lower electrode and the high ferroelectric film can be suppressed, and a capacitor having a high dielectric constant can be obtained.

[0005]

However, in the dielectric thin film element having Pt as the lower electrode as in the above-mentioned conventional technique, when heat treatment is performed at 600 ° C. or higher, many hillocks are generated on the surface of the lower electrode. Therefore, when a voltage is applied between the upper electrode 95 and the lower electrode 93, the electric field concentrates on the hillocks, and the dielectric strength and fatigue resistance of the dielectric thin film element deteriorate. In addition, the presence of this hillock is likely to cause defects because high nucleus growth is hindered when the ferroelectric film 94 is formed, and a good high ferroelectric film cannot be formed. Problems such as a decrease in dielectric constant, a decrease in withstand voltage, and deterioration in fatigue characteristics occur. Furthermore, when an alloy of Pd and Pt is used as an electrode of a dielectric thin film element, since Pd is a metal that is easily oxidized, high and oxygen in the ferroelectric film is high during heat treatment of the ferroelectric film. Is reduced and the composition of the ferroelectric film changes. This causes problems such as a decrease in dielectric constant, a decrease in withstand voltage, and deterioration in fatigue characteristics.

In recent years, Bi layered oxide has been attracting attention as a ferroelectric film having excellent fatigue resistance.
However, since Pt and Bi form Bi ₂ Pt at 640 ° C., it is easy to form an alloy such as Bi ₄ Pt when the Bi layered ferroelectric film is subjected to heat treatment at 640 ° C. or higher using Pt as an electrode. Become. For this reason, the Bi layered ferroelectric film causes a composition change, which causes problems such as a decrease in permittivity, a decrease in withstand voltage, and deterioration in fatigue characteristics.

The present invention has been made in view of these circumstances, and an object thereof is to provide a dielectric thin film element capable of improving withstand voltage, fatigue resistance, and dielectric constant.

[0008]

[Means for Solving the Problems]

1. In a dielectric thin film element having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film, A dielectric thin film element, wherein the lower electrode is made of Pt containing at least one element of Rh, Ru, Os, and Ir.

[Structure] This invention corresponds to the first embodiment. In Example 1, the lower layer of the dielectric thin film element is formed on the substrate. This lower layer corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region as will be described later, but Rh, Ru, Os, and
The structure is such that Pt containing at least one element of Ir is formed, a high ferroelectric film is formed thereon, and Pt is formed thereon as an upper electrode.

[Operation] Rh, Ru, O as the lower electrode
By using Pt containing at least one element of s and Ir, the ductility of Pt is reduced and the rigidity is increased, and the crystal grain size is reduced to reduce the variation of the crystal grain size. As a result, hillocks are not generated on the surface of the lower electrode even if heat treatment is performed at 600 ° C. or higher, flatness is maintained, and nucleus growth during heat treatment of the high ferroelectric film is performed well. The occurrence of defects is suppressed.

[Effect] The absence of abnormal deposits such as hillocks on the surface of the lower electrode can prevent electric field concentration generated when a voltage is applied between the upper electrode and the lower electrode, thus improving dielectric strength and fatigue resistance. can do. Also,
Since the crystal grain size of the lower electrode is small and the variations are small, and there is no hillock, the nucleus generation is high during the heat treatment of the ferroelectric film, and good nucleus growth is performed. A body membrane can be formed. Therefore, a dielectric thin film element having improved dielectric strength, fatigue resistance, and dielectric constant can be obtained.

2. In a dielectric thin film element having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film, The lower electrode comprises a first layer formed on the substrate and a second layer formed on the first layer and in contact with the high and ferroelectric films, and the first layer of the lower electrode is made of Pt. The second layer of the electrode is Ph, Ru, Os, I
A dielectric thin film element comprising Pt containing at least one element of r.

[Structure] The present invention corresponds to the third embodiment. In Example 3, a lower layer of a dielectric thin film element is formed on the substrate. This lower layer is the same as the above 1. In the same manner as in the case (1), it corresponds to an insulating film, a polycrystalline Si layer or a semiconductor diffusion region, but on the substrate as a first layer of the lower electrode, P
t is formed, and Rh as a second layer of the lower electrode is formed thereon,
The structure is such that Pt containing at least one element of Ru, Os and Ir is formed, a high ferroelectric film is formed thereon, and Pt is further formed thereon as an upper electrode. .

[Operation] As a second layer of the lower electrode, Rh,
By using Pt containing at least one element of Ru, Os, and Ir, the ductility of Pt is reduced and the rigidity is increased, and the crystal grain size is reduced to reduce the variation in crystal grain size. As a result, hillocks are not generated on the surface of the second layer of the lower electrode even if the heat treatment is performed at 600 ° C. or higher, flatness is maintained, and nucleus growth during heat treatment of the ferroelectric film is high. Therefore, the occurrence of defects is suppressed. Further, an increase in the lower electrode resistance caused by using Pt containing at least one element of Rh, Ru, Os, and Ir can be prevented by using Pt as the first layer of the lower electrode.

[Effect] Since no abnormal deposits such as hillocks are present on the surface of the second layer of the lower electrode, it is possible to prevent the electric field concentration that occurs when a voltage is applied between the upper electrode and the lower electrode. Fatigue characteristics can be improved. In addition, since the crystal grain size of the second layer of the lower electrode is small and has little variation, and there is no hillock, the nucleation is high during the heat treatment of the ferroelectric film, and good nucleation is performed. It is possible to form a high, ferroelectric film. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength, fatigue resistance, and dielectric constant. Further, by preventing the resistance from increasing due to the use of Pt as the first layer of the lower electrode, the electrode resistance of the conventional dielectric thin film element can be maintained.

3. In a dielectric thin film element having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film, The lower electrode comprises a first layer formed on the substrate and a second layer formed on the first layer and in contact with the high and ferroelectric films, and the first layer of the lower electrode is made of Pt. The second layer of the electrode is Rh, Ru, Os, I
The upper electrode is composed of Pt containing at least one element of r, and the upper electrode is composed of a first layer formed on the high ferroelectric film and a second layer formed on the first layer. A dielectric thin film element, wherein the first layer of the electrode is made of Pt containing at least one element of Rh, Ru, Os and Ir, and the second layer of the upper electrode is made of Pt.

[Structure] The present invention corresponds to the fourth embodiment. In Example 4, the lower layer of the dielectric thin film element is formed on the substrate. This lower layer is the same as the above 1. In the same manner as in the case of 1., it corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region, but on the substrate as a first layer of the lower electrode, P
t is formed, and Rh as a second layer of the lower electrode is formed thereon,
Pt containing at least one element of Ru, Os and Ir is formed, and a high ferroelectric film is formed thereon. Further, Pt containing at least one element of Rh, Ru, Os and Ir is formed as a first layer of the upper electrode on the high ferroelectric film, and Pt is formed as a second layer of the upper electrode on the Pt. Has been formed.

[Operation] As a second layer of the lower electrode, Rh,
By using Pt containing at least one element of Ru, Os, and Ir, the ductility of Pt is reduced and the rigidity is increased, and the crystal grain size is reduced to reduce the variation in crystal grain size. As a result, hillocks are not generated on the surface of the second layer of the lower electrode even if the heat treatment is performed at 600 ° C. or higher, flatness is maintained, and nucleus growth during heat treatment of the ferroelectric film is high. Therefore, the occurrence of defects is suppressed. In addition, Rh, R is also included in the first layer of the upper electrode.
By using Pt containing at least one element of u, Os and Ir, even if a heat treatment at 600 ° C. or higher is performed after the upper electrode is formed, the high and ferroelectric films and the second electrode of the lower electrode and the upper layer are formed. It is possible to prevent abnormal deposits such as hillocks from being generated at the interface of the first layer of the electrode. Furthermore, Rh, Ru, O
An increase in upper and lower electrode resistance due to the use of Pt containing at least one element of s and Ir can be prevented by using Pt as the first layer of the lower electrode and the second layer of the upper electrode.

[Effect] High, since no abnormal deposits such as hillocks exist at the interface between the ferroelectric film and the lower electrode and the upper electrode, the concentration of the electric field generated when a voltage is applied between the upper electrode and the lower electrode is prevented. Therefore, the dielectric strength and fatigue resistance can be improved. In addition, since the crystal grain size of the second layer of the lower electrode is small and has little variation, and there is no hillock, the nucleation is high during the heat treatment of the ferroelectric film, and good nucleation is performed. It is possible to form a high, ferroelectric film. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength, fatigue resistance, and dielectric constant. Further, by preventing Pt from being used as the first layer of the lower electrode and the second layer of the upper electrode, it is possible to maintain the electrode resistance of the conventional dielectric thin film element.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the following four types are considered as typical forms of dielectric thin film elements.

(1) When the substrate is composed of a Si substrate and an insulating film (see FIG. 1): Reference numeral 1 in the figure indicates the Si substrate 2 and this S
The substrate is composed of an insulating film 3 formed on the i-substrate 2. Here, the insulating film 3 is formed by thermal oxidation, CVD, etc. Specifically, for example, SiO ₂ , Si ₃ N ₄ , BP
It consists of SG, PSG and NSG. On the substrate 1, a dielectric thin film element including a lower electrode 4, a high dielectric film 5 and an upper electrode 6 is formed. An insulating film 7 is formed on the entire surface of the substrate 1 including the dielectric thin film element. The material of the insulating film 7 is selected from the materials of the insulating film 3. Insulating film 7 corresponding to a part of the upper electrode 6
An opening 7a is formed in the opening 7a, and a wiring electrode 8 connected to the upper electrode 6 is formed in the opening 7a.

(2) When the substrate is composed of an Si substrate having a semiconductor diffusion region formed on the surface and an insulating film, and the lower electrode is directly connected to the semiconductor diffusion region (see FIG. 2): same as FIG. The members are given the same reference numerals and the description thereof is omitted. Reference numeral 21 in the drawing is a substrate, which is composed of a Si substrate 2 having a semiconductor diffusion region 22 formed on the surface thereof and an insulating film 3 thereon. An opening 3a is formed in the insulating film 3 corresponding to a part of the semiconductor diffusion region 22, and the lower electrode 4 of the dielectric thin film element is connected to the semiconductor diffusion region 22 through the opening 3a.

(3) The substrate is composed of a Si substrate having a semiconductor diffusion region formed on its surface, an insulating film, and a polycrystalline silicon layer,
When the lower electrode is indirectly connected to the semiconductor diffusion region (see FIG. 3): Here, the same members as those in FIGS. 1 and 2 are denoted by the same reference numerals and the description thereof will be omitted. Reference numeral 31 in the drawing is a substrate, which is embedded in the Si substrate 2 having the semiconductor diffusion region 22 formed on the surface thereof, the insulating film 3 thereon, and the opening 3a of the insulating film 3 and around the opening 3a. And a polycrystalline silicon layer (Poly-Si layer) 32 formed on the insulating film 3. The lower electrode 4 of the dielectric thin film element is electrically connected to the semiconductor diffusion region 22 through the polycrystalline silicon layer 31.

(4) The substrate is composed of a Si substrate having a semiconductor diffusion region formed on its surface, an insulating film, and a polycrystalline silicon layer,
When the lower electrode is indirectly connected to the semiconductor diffusion region (see FIG. 4): Here, the same members as those in FIGS. 1 and 2 are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 41 in the drawing denotes a substrate, a Si substrate 2 having a semiconductor diffusion region 22 formed on the surface thereof, an insulating film 3 thereon, and a polycrystalline silicon layer 42 embedded in an opening 3a of the insulating film 3. It consists of and.

[0025]

【Example】

(Embodiment 1) Embodiment 1 of the present invention will be described with reference to the sectional structural view of FIG.

Reference numeral 51 in the drawing denotes a substrate, which is composed of a Si substrate 52 and a thermally oxidized SiO ₂ film 53 thereon. On the substrate 51, a lower electrode 5 constituting a dielectric thin film element is formed.
4, high, ferroelectric film 55 and upper electrode 56 are sequentially formed from the substrate side. Here, the lower electrode 54 has Rh of 5 to 5
It is composed of 50% Pt and has a thickness of 0.2-0.
It is 4 μm. The high and ferroelectric film 55 is made of PZT, Bi layered ferroelectric, etc., and has a thickness of 0.2 to 0.5 μm.
It is. The upper electrode 56 is made of Pt and has a thickness of 0.2 to 0.4 μm.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 was formed on the Si substrate 53 as a lower layer of a dielectric thin film element. Next, Pt containing 5 to 50% by weight of Rh
A lower electrode material layer made of Pt containing 5 to 50% of Rh is formed in a thickness of 0.2 to 0.4 μm by a binary sputtering method using a target or a Pt target and a Rh target.
A film was formed. Next, after forming a high and ferroelectric film material layer by spin coating, CVD or the like to a thickness of 0.2 to 0.5 μm,
Heat treatment was performed at 600 to 800 ° C. Continuing, an upper electrode material layer of Pt is formed thereon by sputtering to 0.2-
A film having a thickness of 0.4 μm was formed. After that, the upper electrode material layer, the high and ferroelectric film material layers and the lower electrode material layer are sequentially formed into a predetermined shape by using ion milling or RIE, and the upper electrode 56, the high and ferroelectric film 55 and the lower portion are formed. The electrode 54 was formed. With the above, a dielectric thin film element of Example 1 of the present invention was manufactured.

SEM observation of the surface of the lower electrode 54 of Example 1 revealed that the crystal grains were small and uniform at about 50 nm, and when the surface was scratched with a diamond indenter having a radius of curvature of 10 μm, the ductility of conventional Pt was low. Therefore, scratches were generated at a load of 10 mN or less, whereas the electrode of Example 1 was a hard film without scratches even at 50 mN. Therefore, when heat treatment is performed at 600 to 800 ° C. after forming the lower electrode 54, the conventional Pt
While many hillocks having a height of 0.1 μm or more were generated on the surface, no abnormal deposits such as hillocks were generated on the electrode of Example 1, and there was no change on the electrode surface before and after the heat treatment.

Therefore, for example, in the conventional element using PZT having a film thickness of 0.2 μm formed by the spin coating method, the electric field is concentrated on the hillock when the voltage is applied between the upper electrode and the lower electrode, and thus the insulation is achieved. While the withstand voltage was about 15V, the dielectric thin film element of Example 1 had a withstand voltage of 20V.
The above dielectric strength is shown. In the conventional element, the withstand voltage depends on the element area, and the larger the element area, the lower the withstand voltage. However, in the element of Example 1, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleus generation during the heat treatment of PZT is uniform and good nucleus growth without defects is performed.

Further, as a result of evaluating the state of reduction of remanent polarization when an AC rectangular wave is continuously applied to the upper electrode and the lower electrode, which is generally performed as a fatigue characteristic test of a ferroelectric film, the conventional device is evaluated. In contrast, the remanent polarization becomes 1/2 of the initial value in about 10 ⁶ cycles, whereas in the element of Example 1, it was 10 ⁷ cycles or more, and the fatigue resistance was improved by one digit or more.

Further, the dielectric constant is about 1000 in the conventional device, while it is 11 in the device of the first embodiment.
It is more than 00 and is improved by 10% or more.

In Example 1, the same result was obtained by using Pt containing at least one element of Rh, Ru, Ir, and Os instead of Rh as the lower electrode, and especially 10%. With the composition contained, the dielectric thin film element with the best characteristics was obtained. This is not limited to the above-described first embodiment and is the same in other embodiments.

In the first embodiment described above, the case of using the substrate consisting of the Si substrate and the thermally-oxidized SiO ₂ film thereon was described, but the present invention is not limited to this. For example, a glass substrate may be used instead of the substrate, or a BPSG film, a PSG film, an NSG film by CVD instead of the thermally oxidized SiO ₂ film,
An insulating film such as a Si ₃ N ₄ film may be used. This means
The same applies to the other embodiments as well as the first embodiment.

In the first embodiment described above, the case where the upper electrode is Pt has been described.
₂ O ₂ , In ₂ O ₃ , RuO ₂ , RhO ₂ , ReO ₂ ,
An electrode made of a conductive oxide containing at least one of OsO ₂ and IrO ₂ as a main component may be formed. This makes it possible to prevent the elements composing the high ferroelectric film from diffusing to the wiring electrode and the interlayer insulating film side, and the elements composing the wiring electrode and the interlayer insulating film to the high ferroelectric film side. It can be prevented from spreading. Further, it is possible to prevent hillocks from being generated in the upper electrode and the lower electrode, and these things can be similarly applied to each embodiment.

In the first embodiment, the upper electrode material layer,
The high and ferroelectric film material layers and the lower electrode material layer may be patterned at the same time or separately.
This is not limited to Embodiment 1 described above, and is the same for other embodiments.

In the first embodiment described above, Ti, Ta, Cr, W, Ti is provided between the lower electrode and the substrate or on the upper electrode.
You may form the adhesive layer which consists of W, TiN, etc. As a result, the adhesiveness between the lower electrode and the substrate or between the upper electrode and the wiring electrode described in FIGS. 1 to 4 is improved.

(Second Embodiment) A second embodiment of the present invention will be described with reference to the sectional structural view of FIG. However, the description of the same members as in the first embodiment will be omitted. Example 2 is different from Example 1 in that the upper electrode 56 is made of Pt containing 5 to 50% of Rh. The thickness of the upper electrode 56 is 0.2 to, as in the first embodiment.
It is 0.4 μm.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 was formed on the Si substrate 53 as a lower layer of a dielectric thin film element.
Subsequently, a Pt target containing 5 to 50% by weight of Rh or a lower electrode material layer of Pt containing 5 to 50% of Rh was formed by a binary sputtering method using a Pt target and a Rh target. A film having a thickness of 0.4 μm was formed. Next, after forming a high and ferroelectric film material layer by spin coating, CVD or the like to a thickness of 0.2 to 0.5 μm, 60
Heat treatment was performed at 0 to 800 ° C. Subsequently, an upper electrode material layer made of Pt containing 5 to 50% of Rh is formed on the Pt target containing 5 to 50% by weight of Rh or a binary sputtering method using a Pt target and a Rh target. A film having a thickness of 0.2 to 0.4 μm was formed. After that, the upper electrode material layer, the high and ferroelectric film material layers and the lower electrode material layer are sequentially formed into a predetermined shape by using ion milling or RIE, and the upper electrode 56, the high and ferroelectric film 5 are formed.
5, the lower electrode 54 was formed, and the dielectric thin film element was produced.

SEM observation of the surface of the lower electrode 54 of Example 2 revealed that the crystal grains were small and uniform at about 50 nm, and when the surface was scratched with a diamond indenter having a radius of curvature of 10 μm, the ductility of conventional Pt was low. Because of this, scratches were generated under a load of 10 mN or less, whereas the electrode of Example 2 was a hard film without scratches even at 50 mN. Therefore, when heat treatment is performed at 600 to 800 ° C. after forming the lower electrode 54, the conventional Pt
While many hillocks having a height of 0.1 μm or more were generated on the surface, no abnormal deposits such as hillocks were generated on the electrode of Example 2, and there was no change on the electrode surface before and after the heat treatment. Further, also at the interface between the upper electrode 56 and the high ferroelectric film 55, no abnormal deposit such as hillock was generated after the final heat treatment.

Therefore, for example, in the conventional element using PZT having a film thickness of 0.2 μm formed by the spin coating method, the electric field is concentrated on the hillock when the voltage is applied between the upper electrode and the lower electrode. The withstand voltage was about 15V, whereas the dielectric thin film element of Example 2 had a voltage of 20V.
The above dielectric strength is shown. In the conventional element, the withstand voltage depends on the element area, and the higher the element area, the lower the withstand voltage. However, in the element of Example 2, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleus generation during the heat treatment of PZT is uniform and good nucleus growth without defects is performed.

Further, as a result of evaluating the state of reduction of remanent polarization when an AC rectangular wave is continuously applied to the upper electrode and the lower electrode, which is generally performed as a fatigue characteristic test for high and ferroelectric films, the result is as follows. In the device of No. 2, the residual polarization becomes 1/2 of the initial value in about 10 ⁶ cycles, whereas in the device of Example 2, it was 10 ⁷ cycles or more, and the fatigue resistance was improved by one digit or more.

Further, the dielectric constant is about 1000 in the conventional element, while it is 11 in the element of the second embodiment.
It is more than 00 and is improved by 10% or more.

(Embodiment 3) A third embodiment of the present invention will be described with reference to the sectional structural view of FIG. However, the same members as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted, and only the main parts will be described. The third embodiment is higher than the first embodiment in that the ferroelectric film 55 and the upper electrode are high.
The configuration of 56 is the same, only the lower electrode 54 is different. The lower electrode 54 includes a first layer 54a made of Pt and having a thickness of 0.2 to 0.4 μm, and a second layer 54b made of Pt containing 5 to 50% of Rh and having a thickness of 0.2 to 0.4 μm. Composed.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then Pt is sputtered to form a first layer of a lower electrode with a thickness of 0.2 to
A Pt target or Pt containing a 0.4 μm material layer and further containing 5 to 50% by weight of Rh.
A two-dimensional sputtering method using a target and a Rh target was used to deposit a material layer of Pt containing 5 to 50% of Rh and having a thickness of 0.2 to 0.4 μm to be the second layer of the lower electrode. Next, after forming a high and ferroelectric film material layer by spin coating, CVD or the like to a thickness of 0.2 to 0.5 μm,
Heat treatment was performed at 00 to 800 ° C. Continuing, an upper electrode material layer of Pt is formed thereon by sputtering to 0.2-
A film having a thickness of 0.4 μm was formed. After that, by using ion milling or RIE, the upper electrode material layer, the high and ferroelectric film material layers and the lower electrode material layer are sequentially formed into a predetermined shape, and the upper electrode 56, the high and ferroelectric film 55, First layer 54a and second layer 54b
A lower electrode 54 composed of was formed, and a dielectric thin film element was manufactured.

SEM observation of the surface of the second layer 54b of the lower electrode 54 of Example 3 showed that the crystal grains were small and uniform, about 50 nm, and that when scratched with a diamond indenter having a radius of curvature of 10 μm, Since Pt had ductility, scratches were generated under a load of 10 mN or less, whereas the electrode of Example 3 was a hard film without scratches even at 50 mN. Therefore, when heat treatment is performed at 600 to 800 ° C. after forming the lower electrode,
In the conventional Pt, many hillocks having a height of 0.1 μm or more were generated on the surface, whereas in the electrode of Example 3, abnormal deposits such as hillocks were not generated at all, and there was no change in the electrode surface before and after the heat treatment. It was

Therefore, for example, in the conventional element using PZT having a film thickness of 0.2 μm formed by the spin coating method, the electric field is concentrated on the hillocks when the voltage is applied between the upper electrode and the lower electrode, and thus the insulation is achieved. The withstand voltage was about 15 V, whereas the dielectric thin film element of Example 3 had a withstand voltage of 20 V.
The above dielectric strength is shown. Further, in the conventional element, the withstand voltage depends on the element area, and the larger the element area, the lower the withstand voltage. However, in the element of Example 3, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleus generation during the heat treatment of PZT is uniform and good nucleus growth without defects is performed.

In addition, as a result of evaluating the state of reduction of remanent polarization when an AC rectangular wave is continuously applied to the upper electrode and the lower electrode, which is generally performed as a fatigue characteristic test for high and ferroelectric films, the result is as follows. In the device of No. 3, the residual polarization becomes half of the initial value in about 10 ⁶ cycles, whereas in the device of Example 3, it was 10 ⁷ cycles or more, and the fatigue resistance was improved by one digit or more.

Further, the dielectric constant is about 1000 in the conventional device, while it is 11 in the device of the third embodiment.
It is more than 00 and is improved by 10% or more.

Further, the Pt electrode containing at least one element of Rh, Ru, Ir, and Os tends to have a higher electric resistance than the Pt electrode, but Pt as the first layer of the lower electrode. By backing with electrodes, the same electric resistance as that of the electrodes of the conventional device was obtained.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to the sectional structural view of FIG. However, the same members as those in FIGS. 5 and 6 are denoted by the same reference numerals, and the description thereof will be omitted, and only the main parts will be described.
The upper electrode 56 includes a first layer 56a made of Pt containing 5 to 50% of Rh and having a thickness of 0.2 to 0.4 μm, and the first layer 56a.
formed on a and having a thickness of 0.2 to 0.4 μm made of Pt
Of the second layer 56b.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then Pt is sputtered to form a first layer of a lower electrode having a thickness of 0.2 to
A Pt target or Pt containing a 0.4 μm material layer and further containing 5 to 50% by weight of Rh.
A material layer to be the second layer of the lower electrode made of Pt containing Rh in an amount of 5 to 50% was formed to a thickness of 0.2 to 0.4 μm by a binary sputtering method using a target and an Rh target. Next, spin coating a high and ferroelectric film 55, C
After forming a film of 0.2 to 0.5 μm by VD or the like, 600 to 8
Heat treatment was performed at 00 ° C. Continuing, a Pt target or P containing Rh in an amount of 5 to 50% by weight is further added.
By a two-way sputtering method using a t target and a Rh target, a material layer to be the first layer of the upper electrode made of Pt containing 5 to 50% of Rh is formed to a thickness of 0.2 to 0.4 μm, and further thereon. Then, a material layer made of Pt to be the second layer of the upper electrode was formed to a thickness of 0.2 to 0.4 μm by sputtering. Then, ion milling or RIE is used to sequentially form each material layer of the upper electrode, the high and ferroelectric material layers, and the material layer of the lower electrode into a predetermined shape, and finally 600 to 800.
Then, a heat treatment at ℃ is applied to form an upper electrode 56 composed of the first layer 56a and the second layer 56b, a high ferroelectric film 55 and a lower electrode 54 composed of the first layer 54a and the second layer 54b. A thin film element was produced.

SEM observation of the surface of the second layer 54b of the lower electrode 54 of Example 4 revealed that the crystal grains were small and uniform at about 50 nm, and the surface was scratched with a diamond indenter having a radius of curvature of 10 μm. Since Pt had ductility, scratches were generated under a load of 10 mN or less, whereas the electrode of Example 4 was a hard film without scratches even at 50 mN. Therefore, when heat treatment is performed at 600 to 800 ° C. after forming the lower electrode,
In the conventional Pt, a large number of hillocks having a height of 0.1 μm or more were generated on the surface, whereas in the electrode of Example 4, abnormal deposits such as hillocks were not generated at all, and there was no change in the electrode surface before and after the heat treatment. It was Furthermore, the upper electrode 56 and high and ferroelectric films
Even at the 55 interface, no abnormal precipitate such as hillock was generated after the final heat treatment.

Therefore, for example, in the conventional element using PZT having a film thickness of 0.2 μm formed by the spin coating method, the electric field is concentrated on the hillock when the voltage is applied between the upper electrode and the lower electrode. The withstand voltage was about 15V, whereas the dielectric thin film element of Example 4 had a withstand voltage of 20V.
The above dielectric strength is shown. In the conventional element, the withstand voltage depends on the element area, and the larger the element area, the lower the withstand voltage. However, in the element of Example 4, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleus generation during the heat treatment of PZT is uniform and good nucleus growth without defects is performed.

In addition, as a result of evaluating the state of reduction of remanent polarization when an AC rectangular wave is continuously applied to the upper electrode and the lower electrode, which is generally performed as a fatigue characteristic test of a ferroelectric film, the conventional device is evaluated. In contrast, the remanent polarization becomes half of the initial value in about 10 ⁶ cycles, whereas in the element of Example 4, it was 10 ⁷ cycles or more, and the fatigue resistance was improved by one digit or more.

Further, the dielectric constant is about 1000 in the conventional element, while it is 110 in the embodiment.
It became 0 or more and improved by 10% or more.

In Example 4, similar results were obtained even if Pt containing at least one element of Rh, Ru, Ir, and Os was used in place of Rh as the first layer of the upper electrode. With the composition containing 10% in particular, the dielectric thin film element having the best characteristics was obtained. This point is not limited to Embodiment 4 described above, and is the same for other embodiments using the above material such as Rh as the first layer of the upper electrode.

The Pt electrode containing at least one element of Rh, Ru, Ir, and Os tends to have higher electric resistance than the Pt electrode, but the first layer of the lower electrode and the upper electrode. By lining with a Pt electrode as the second layer of, the same electric resistance as the electrode of the conventional element was obtained.

(Embodiment 5) Embodiment 5 of the present invention will be described with reference to the sectional structural view of FIG. However, the same members as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted, and only the main parts will be described. The fifth embodiment has a higher ferroelectric film 55 and upper electrode than the third embodiment.
56 has the same configuration, but only the configuration of the lower electrode 54 is different. The lower electrode 54 has a thickness of 0.05 to 0.4 μm and a first layer 54a made of ITO as a conductive oxide, and a Pt containing 5 to 50% of Rh formed on the first layer 54a. .2
.About.0.4 .mu.m of the second layer 54b. Upper electrode 56
Is the same as in the third embodiment.

The dielectric thin film element thus constructed is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then ITO is formed.
Is formed into a first layer of the lower electrode by sputtering with a thickness of 0.0
A material layer of 5 to 0.4 μm is formed, and Rh is formed on the material layer.
By Pt target containing 5 to 50% by weight or a binary sputtering method using a Pt target and a Rh target, and Pt containing 5 to 50% of Rh. A material layer having a thickness of 2 to 0.4 μm was formed. Next, a high ferroelectric film material layer was formed to a thickness of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Subsequently, an upper electrode material layer of Pt was formed thereon by sputtering to a thickness of 0.2 to 0.4 μm. After that, the upper electrode material layer, the high and ferroelectric film material layers and the lower electrode material layers are sequentially formed into a predetermined shape by using ion milling or RIE, and the upper electrode 56, the high and ferroelectric film 55 are formed. A lower electrode 54 composed of the first layer 54a and the second layer 54b was formed to manufacture a dielectric thin film element.

SEM observation of the surface of the second layer 54b of the lower electrode 54 of Example 5 revealed that it was 50 mN as in Example 3.
However, it was a hard film without scratches. Therefore,
In the electrode of Example 5, no abnormal deposit such as hillock was generated, and the electrode surface was not changed before and after the heat treatment.

Therefore, in the dielectric thin film element of Example 5, 2
It showed a withstand voltage of 0 V or higher. Further, since the withstand voltage of the element of Example 5 did not depend on the element area and showed a constant value, the nucleus generation during PZT heat treatment was uniform, and good nucleus growth without defects was performed. Can be said. Further, in the device of Example 5, when the fatigue property test of the ferroelectric film was performed, it was 10 ⁷ cycles or more as in Example 3, and the fatigue resistance property was improved by one digit or more. Furthermore, Example 5
In the element of 1), it is 1100 or more, which is an improvement of 10% or more.

Further, by using ITO as the first layer of the lower electrode, the adhesiveness with the lower layer is improved, and the peeling of the film, which is a problem in the conventional element, can be prevented.
Higher constituent elements (such as Si) in the lower layer, diffusion into the ferroelectric film,
Further, it has become possible to prevent the diffusion of the constituent elements of the high ferroelectric film to the lower layer.

Although ITO is used as the first layer of the lower electrode in the above embodiment, other conductive oxides such as SnO ₂ , In ₂ O ₃ , RuO ₂ and RhO are used instead of ITO.
Similar results were obtained using an electrode containing at least one of ₂ , ReO ₂ , OsO ₂ , and IrO ₂ . This also applies to other examples using a conductive oxide as the first layer of the lower electrode.

(Sixth Embodiment) A sixth embodiment of the present invention will be described with reference to the sectional structural view of FIG. However, the same members as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted, and only the main parts will be described. The sixth embodiment is different from the fifth embodiment in that the lower electrode 54 and the high ferroelectric material 55 are used.
Has the same configuration as that of the fifth embodiment, but only the configuration of the upper electrode 56 is different. The upper electrode 56 is composed of Pt containing 5 to 50% of Rh.

The ferroelectric thin film element having such a structure is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then IT
O is used as a first layer of the lower electrode by sputtering to a thickness of 0.
A material layer having a thickness of 05 to 0.4 μm is formed, and R is further formed thereon.
A Pt target containing 5 to 50% of h by weight or a binary sputtering method using a Pt target and a Rh target, which is made of Pt containing 5 to 50% of Rh and forms a second layer of the lower electrode having a thickness of 0. A material layer having a thickness of 0.2 to 0.4 μm was formed. Next, a high ferroelectric film material layer was formed to a thickness of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Subsequently, an upper electrode material layer made of Pt containing 5 to 50% of Rh is sputtered thereon by a Pt target containing 5 to 50% by weight of Rh or a binary sputtering method using a Pt target and a Rh target. With 0.
A film having a thickness of 2 to 0.4 μm was formed. Then, the upper electrode material layer, the high and ferroelectric film material layers, and the lower electrode material layers are sequentially formed into a predetermined shape by using ion milling or RIE, and finally heat-treated at 600 to 800 ° C. Then, the lower electrode 54 including the upper electrode 56, the high ferroelectric film 55, the first layer 54a and the second layer 54b was formed to manufacture a dielectric thin film element.

SEM observation of the surface of the second layer 54b of the lower electrode 54 of Example 6 revealed that it was 50 mN as in Example 3.
However, it was a hard film without scratches. Therefore,
In the electrode of Example 6, no abnormal deposit such as hillock was generated, and the electrode surface was not changed before and after the heat treatment.

No abnormal deposits such as hillocks were generated at the interface between the upper electrode 56 and the high ferroelectric film 55 after the final heat treatment. Furthermore, as a result of XPS elemental analysis in the depth direction, the lower electrode was
In this case, the element of the thermally-oxidized SiO ₂ film 53, which was high and caused the deterioration of the characteristics of the ferroelectric film, was diffused to the Pt surface, whereas the structure of Example 6 was used. It was found that ITO acts as a diffusion barrier and prevents the diffusion of Si.

Therefore, in the dielectric thin film element of Example 6,
Similar to Example 3, it showed a withstand voltage of 20 V or higher. Further, in the element of Example 6, the withstand voltage showed a constant value independent of the element area, so that the nucleus generation during PZT heat treatment was uniform and good nucleus growth without defects was performed. Can be said. Furthermore, in the device of Example 5, an order of magnitude or more is 10 ⁷ cycles or more, fatigue resistance is improved. Furthermore, in the device of Example 5, when the fatigue property test of the ferroelectric film was performed, it was 1100 or more as in Example 3, and
It has improved by 10% or more. In addition, ITO is used as the lower electrode.
By using, it is possible to prevent film peeling, and to increase the amount of constituent elements (Si, etc.) in the lower layer to the ferroelectric film and to diffuse the constituent elements of the high and ferroelectric film to the lower layer. Can be prevented.

Similar results can be obtained by using Pt containing at least one main element of Rh, Ru, Ir, and Os instead of Rh as the second layer of the lower electrode and the upper electrode. With the composition containing 10%, the dielectric thin film element having the best characteristics was obtained. This also applies to the other embodiments.

(Embodiment 7) Embodiment 7 of the present invention will be described with reference to the sectional structural view of FIG. However, the same members as those in FIGS. 5 and 7 are designated by the same reference numerals and the description thereof will be omitted. The high ferroelectric film 55 and the upper electrode 56 are the same as in the fourth embodiment. The lower electrode 54 is I
First layer 54a made of TO and having a thickness of 0.05 to 0.4 μm
And a second layer 54b made of Pt and having a thickness of 0.2 to 0.4 μm.
And a thickness of Pt containing Rh of 5 to 50% of 0.2
.About.0.4 .mu.m third layer 54c.

The dielectric thin film element thus constructed is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then ITO is formed.
Is formed into a first layer of the lower electrode by sputtering with a thickness of 0.0
A material layer having a thickness of 5 to 0.4 μm is formed, and Pt to be the second layer of the lower electrode is formed thereon by sputtering to 0.2 to 0.4 μm.
By forming a film and further forming a Pt target containing 5 to 50% by weight of Rh on the Pt target or a binary sputtering method using a Pt target and a Rh target, Rh is set to 5 to 5
A material layer to be the third layer of the lower electrode made of Pt containing 0% was formed to a thickness of 0.2 to 0.4 μm. Next, a high and ferroelectric film material layer is formed by spin coating, CVD, etc.
After forming a film having a thickness of 0.5 μm, a heat treatment at 600 to 800 ° C. was performed. Continue to add Rh on top of it in a weight ratio of 5 to 50
% Pt target or Pt target and R
The upper electrode material layer made of Pt containing 5 to 50% of Rh was formed into Pt by the binary sputtering method using the h target.
Of 0.2 to 0.4 μm was formed by sputtering. Then, the upper electrode material layer, the high and ferroelectric film material layers, and the lower electrode material layers are sequentially formed into a predetermined shape by using ion milling or RIE, and finally heat-treated at 600 to 800 ° C. An upper electrode 56 comprising a first layer 56a and a second layer 56b, a high ferroelectric film 55, a first layer 54a, a second layer 54b.
Then, the lower electrode 54 composed of the third layer 54c and the third layer 54c was formed to manufacture a dielectric thin film element.

SEM observation of the surface of the third layer 54c of the lower electrode 54 of Example 7 revealed that it was 50 mN as in Example 3.
However, it was a hard film without scratches. Therefore,
In the electrode of Example 6, no abnormal deposit such as hillock was generated, and the electrode surface was not changed before and after the heat treatment.

Further, also at the interface between the upper electrode 56 and the high ferroelectric film 55, no abnormal precipitate such as hillock was generated after the final heat treatment. Further, as a result of performing an elemental analysis in the depth direction by XPS, it is found that ITO, which is the material of the first layer 54a of the lower electrode 54, functions as a diffusion barrier and prevents the diffusion of Si, as in Example 7. all right.

Therefore, in the dielectric thin film element of Example 7,
Similar to Example 3, it showed a withstand voltage of 20 V or higher. Further, in the element of Example 7, the withstand voltage showed a constant value without depending on the element area, so that the nucleus generation during PZT heat treatment was uniform and good nucleus growth without defects was performed. Can be said. Furthermore, in the device of Example 7 1 order of magnitude or more is 10 ⁷ cycles or more, fatigue resistance is improved. Furthermore, the device of Example 7 has a value of 1100 or more, which is an improvement of 10% or more. In addition, ITO is used as the first layer of the lower electrode.
By using, it is possible to prevent film peeling, and to increase the amount of constituent elements (Si, etc.) in the lower layer to the ferroelectric film and to diffuse the constituent elements of the high and ferroelectric film to the lower layer. Can be prevented.

Although the Pt electrode containing at least one element of Rh, Ru, Ir, and Os tends to have a higher electric resistance than the Pt electrode, the second layer of the lower electrode and the upper electrode. By lining with a Pt electrode as the second layer of, the same electric resistance as the electrode of the conventional element was obtained.

(Embodiment 8) An embodiment 8 of the present invention will be described with reference to the sectional structural view of FIG. However, the same members as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Example 8 is the same as Example 1.
The upper electrode 56 has the same configuration as that of the lower electrode 54
And the structure of the high and ferroelectric films 55 is different. The lower electrode 54 is B
It is composed of Pt containing 5 to 80% of i and has a thickness of 0.2 to 0.4 μm. Also, high, ferroelectric film 55
Is a Bi layered ferroelectric film having a thickness of 0.2 to 0.4 μm.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then Bi
A lower electrode material layer made of Pt containing 5 to 80% of Bi by a binary sputtering method using a Pt target containing 5 to 80% by atomic ratio or a Pt target and a Bi target of 0.2 to 0.4 μm. A film was formed. Subsequently, a Bi layered ferroelectric film material layer was formed thereon by spin coating, CVD or the like to have a film thickness of 0.2 to 0.5 μm, and then heat treatment was performed at 600 to 800 ° C. Further, Pt is used as the upper electrode material layer by sputtering to form 0.2 to
A film having a thickness of 0.4 μm was formed. Then, using ion milling or RIE, an upper electrode material layer, a Bi layered ferroelectric film material layer, and a lower electrode material layer are sequentially formed into a predetermined shape,
An upper electrode 56, a Bi layered ferroelectric film 55 and a lower electrode 54 were formed to manufacture a dielectric thin film element.

As a result of performing elemental analysis in the depth direction by XPS on the conventional element having only Pt as the lower electrode and the element of Example 8, B of the Bi layered ferroelectric film was found in the conventional element.
While i diffused into Pt of the lower electrode, no such diffusion was observed in the element of Example 8, and the composition change at the interface of the lower electrode 54 of the Bi layered ferroelectric film 55 occurred. There wasn't. The lower electrode 54 had a composition such as Bi ₂ Pt or BiPt. Therefore, when a voltage is applied between the upper and lower electrodes, the conventional element has a withstand voltage of 5V.
In contrast to this, the device of Example 8 showed a withstand voltage of 10 V or higher. Further, the dielectric constant of the conventional device is about 250, while the dielectric constant of the device of the example is 300 or more, which is improved by 20% or more.

When the Bi layered ferroelectric film 55 contains Sr, similar results were obtained by using Pt containing Bi and Sr as the lower electrode. Furthermore B
In Pt containing i, the atomic ratio of Bi: Pt = 2:
With the composition of 1 or 1: 1, the dielectric thin film element having the best characteristics was obtained. This also applies to the other embodiments.

(Ninth Embodiment) A ninth embodiment of the present invention will be described with reference to the sectional structural view of FIG. However, the same members as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Example 9 is the same as Example 1.
Compared with the lower electrode 54 and high, the ferroelectric film 55 and the upper electrode
56 configurations are different. That is, the lower electrode 54 contains Bi of 5 to 80
% Of Pt, and its thickness is 0.2-0.
It is 4 μm. The high, ferroelectric film 55 has a thickness of 0.2-0.
It is a 5 μm Bi layered ferroelectric film. The upper electrode 56 is Bi
Is composed of 5 to 80% of Pt and has a thickness of 0.2
Is about 0.4 μm.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then Bi
A lower electrode material layer made of Pt containing 5 to 80% of Bi by a binary sputtering method using a Pt target containing 5 to 80% by atomic ratio or a Pt target and a Bi target of 0.2 to 0.4 μm. A film was formed. Subsequently, a high ferroelectric film material layer is formed thereon by spin coating, CVD or the like to a thickness of 0.2 to 0.5 μm, and then 6
Heat treatment was performed at 00 to 800 ° C. On top of that, B
The upper electrode material layer made of Pt containing 5 to 80% of Bi is used to form an upper electrode material layer of 0.2 to 0.2% by a binary sputtering method using a Pt target containing 5 to 80% of i in atomic ratio or a Pt target and a Bi target. A film having a thickness of 4 μm was formed. After that, the upper electrode material layer, the high and ferroelectric film material layers and the lower electrode material layer are sequentially formed into a predetermined shape by using ion milling or RIE, and the upper electrode 56, the high and ferroelectric film 55 are formed.
Then, the lower electrode 54 was formed, and the dielectric thin film element was manufactured.

According to the ninth embodiment, as in the eighth embodiment, XP
As a result of elemental analysis in the depth direction by S, Bi in the Bi layered ferroelectric film did not diffuse to Pt of the lower electrode, and the composition change at the interface of the lower electrode 54 of the high ferroelectric film 55 was confirmed. It didn't happen. The lower electrode 54 had a composition such as Bi ₂ Pt or BiPt. Therefore, Example 9
In the element No. 3, as in the case of Example 8, the withstand voltage of 10 V or higher is exhibited, and the dielectric constant is also 300 or higher, which is improved by 20% or more as compared with the conventional one.

When the high ferroelectric film 55 contains Sr, Bi and Sr are used as the upper electrode and the lower electrode.
Similar results were obtained by using Pt containing.
Furthermore, in Pt containing Bi, the atomic ratio of Bi:
With the composition of Pt = 2: 1 or 1: 1, the dielectric thin film element with the best characteristics was obtained.

(Embodiment 10) FIG. 6 shows Embodiment 10 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIG. In comparison with the third embodiment, the tenth embodiment has the same configuration of the upper electrode 56, and has a high ferroelectric film.
The configurations of 55 and the lower electrode 54 are different. The high and ferroelectric film 55 is composed of a Bi layered ferroelectric film having a thickness of 0.2 to 0.5 μm, and the lower electrode 54 is made of Pt and has a thickness of 0.2 to 0.4 μm.
m of the first layer 54a and Bi formed on the first layer 54a of 5 to 80%
It is composed of the second layer 54b containing Pt.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then Pt is used as a first layer material layer of a lower electrode to form 0.2 to 0. 4μm film is formed, and Bi is further formed on it.
By a binary sputtering method using a Pt target containing 5 to 80% by atomic ratio or a Pt target and a Bi target as a material layer of the second layer of the lower electrode made of Pt containing 5 to 80% Bi. A film having a thickness of 2 to 0.4 μm was formed. Subsequently, a high ferroelectric film material layer was formed into a film of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Further, an upper electrode material layer made of Pt is further formed thereon by a sputtering method with a thickness of 0.2.
A film having a thickness of 0.4 μm was formed. After that, the upper electrode material layer, the high and ferroelectric film material layers and the lower electrode material layers are sequentially formed into a predetermined shape by using ion milling or RIE, and the upper electrode 56, the high and ferroelectric film 55 are formed. Then, the lower electrode 54 composed of the first layer 54a and the second layer 54b was formed to manufacture a dielectric thin film element.

According to the tenth embodiment, as in the eighth embodiment, X
As a result of performing an elemental analysis in the depth direction by PS, Bi in the Bi layered ferroelectric film did not diffuse into Pt of the lower electrode, and the composition change at the interface of the lower electrode 54 of the high ferroelectric film 55 was confirmed. It didn't happen. The lower electrode 54 had a composition such as Bi ₂ Pt or BiPt. Therefore, Example 1
The element of No. 0 also showed a withstand voltage of 10 V or higher, and the dielectric constant was 300 or higher, which was improved by 20% or more as compared with the conventional example, as in Example 8.

Although the Pt electrode containing Bi or Bi and Sr tends to have a higher electric resistance than the Pt electrode, by lining it with the Pt electrode as the first layer of the lower electrode, An electric resistance similar to that of the electrode of the conventional device was obtained.

(Embodiment 11) FIG. 7 shows Embodiment 11 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIG. The eleventh embodiment is different from the fourth embodiment in that the lower electrode 54, the high ferroelectric film 55 and the upper electrode.
56 configurations are different. That is, the lower electrode 54 includes a first layer 54a made of Pt and having a thickness of 0.2 to 0.4 μm, and Bi of 5 to 8
The second layer 54b is composed of 0% Pt and has a thickness of 0.2 to 0.4 μm. Also, high and ferroelectric films
55 is composed of a Bi layered ferroelectric film having a thickness of 0.2 to 0.5 μm. Further, the upper electrode 56 contains Bi of 5 to 80%.
First layer of Pt containing 0.2 to 0.4 μm in thickness
56a and a second layer of Pt having a thickness of 0.2 to 0.4 μm
56b and.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then Pt is used as a first layer material layer of a lower electrode to form 0.2 to 0. 4μm film is formed, and Bi is further formed on it.
By a binary sputtering method using a Pt target containing 5 to 80% by atomic ratio or a Pt target and a Bi target as a material layer of the second layer of the lower electrode made of Pt containing 5 to 80% Bi. A film having a thickness of 2 to 0.4 μm was formed. Subsequently, a high ferroelectric film material layer was formed into a film of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Furthermore, a Pt target containing Bi in an atomic ratio of 5 to 80% or a binary sputtering method using a Pt target and a Bi target was used to form a first layer of an upper electrode made of Pt containing Bi in an amount of 5 to 80%. A material layer was formed in a thickness of 0.2 to 0.4 μm, and Pt was formed thereon as a second material layer of the upper electrode by sputtering to a thickness of 0.2 to 0.4 μm. afterwards,
By using ion milling or RIE, an upper electrode material layer, a high and a ferroelectric film material layer and a lower electrode material layer are sequentially formed into a predetermined shape, and finally heat treatment is performed at 600 to 800 ° C. to form an upper electrode 56, A high dielectric film 55 and a lower electrode 54 were formed to manufacture a dielectric thin film element.

According to the eleventh embodiment, the conventional upper electrode, the element having only Pt as the lower electrode, and the element of the embodiment are XP
As a result of elemental analysis in the depth direction by S, in the conventional element, high Bi in the ferroelectric film diffused into Pt of the upper electrode and the lower electrode, whereas in the element of Example 11, No such diffusion was observed, and there was no change in composition at the interface of the upper and lower electrodes 56 and 54 of the ferroelectric film 55. The upper electrode 56 and the lower electrode 54 have a composition such as Bi ₂ Pt or BiPt.

Therefore, also in the element of the eleventh embodiment, similar to the eighth embodiment, the withstand voltage of 10 V or more is exhibited, and the dielectric constant is 300 or more, which is improved by 20% or more as compared with the conventional one.

When the high ferroelectric film contains Sr, similar results were obtained by using Pt containing Bi and Sr as the upper electrode and the lower electrode. Further, in Pt containing Bi, the atomic ratio of Bi: Pt is
= 2: 1 or 1: 1 composition with the best high characteristics,
A ferroelectric device was obtained.

Further, the Pt electrode containing Bi or Bi and Sr tends to have a higher electric resistance than the Pt electrode, but the Pt electrode is used as the first layer of the lower electrode and the second layer of the upper electrode. By lining with
An electric resistance similar to that of the electrode of the conventional device was obtained, which is the same in other examples.

(Embodiment 12) FIG. 6 shows Embodiment 12 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIG. The twelfth embodiment has the same structure as the ferroelectric film 55 and the upper electrode 56, but the lower electrode 54 has a different structure, as compared with the tenth embodiment. Bottom electrode 54
Is a first layer of ITO having a thickness of 0.05 to 0.4 μm
54a and a second layer 54b made of Pt containing 5 to 80% of Bi and having a thickness of 0.2 to 0.4 μm.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then ITO is used as the first material layer 1 of the lower electrode to form 0.05 to 0 by sputtering. .4 μm film was formed on the Pt target containing Bi in an atomic ratio of 5 to 80%, or a lower part of Pt containing Bi in an amount of 5 to 80% by a binary sputtering method using a Pt target and a Bi target. The material layer of the second layer of the electrode was formed to have a thickness of 0.2 to 0.4 μm. Subsequently, a high ferroelectric film material layer was formed into a film of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Furthermore, an upper electrode material layer made of Pt is formed thereon by sputtering.
A film having a thickness of 2 to 0.4 μm was formed. Then, using ion milling or RIE, the upper electrode material layer, the high and ferroelectric film material layers, and the lower electrode material layer are sequentially formed into a predetermined shape,
Upper electrode 56, high, ferroelectric film 55 and first layer 54a, second layer
A lower electrode 54 composed of 54b was formed to manufacture a dielectric thin film element.

According to the twelfth embodiment, as in the eighth embodiment, X
As a result of performing an elemental analysis in the depth direction by PS, the composition change at the interface of the high and ferroelectric films 55 without lowering Bi in the high and ferroelectric films 55 to Pt of the lower electrodes. Did not occur. The lower electrode 54 had a composition such as Bi ₂ Pt or BiPt. Therefore, Example 1
The element of No. 2 also showed a withstand voltage of 10 V or higher, and the dielectric constant was 300 or higher, which was improved by 20% or more as compared with the conventional device, as in Example 8.

When the high ferroelectric film 55 contains Sr, Bi and Sr are used as the second layer 54b of the lower electrode 54.
Similar results were obtained by using Pt containing.
Furthermore, in Pt containing Bi, the atomic ratio of Bi:
With the composition of Pt = 2: 1 or 1: 1, the dielectric thin film element with the best characteristics was obtained.

Further, by using ITO as the first layer of the lower electrode, the adhesiveness with the lower layer is improved, and the peeling of the film, which was a problem in the conventional element, can be prevented.
Higher constituent elements (such as Si) in the lower layer, diffusion into the ferroelectric film,
And, it has become possible to prevent the diffusion of the constituent elements of the high and ferroelectric films to the lower layers.

Furthermore, ITO is used as the first layer of the lower electrode.
Instead of SnO ₂ , In ₂ O ₃ , RuO ₂ , Rh
Similar results were obtained by using an electrode containing at least one of O ₂ , ReO ₂ , OsO ₂ , and IrO ₂ as a main component. This also applies to the other embodiments.

(Embodiment 13) FIG. 6 shows Embodiment 13 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIG. The thirteenth embodiment has the same configuration of the lower electrode 54 and the high ferroelectric film 55 as compared with the twelfth embodiment, but the configuration of the upper electrode 54 is different. That is, the upper electrode 55 is composed of Pt containing 5 to 80% of Bi.

The dielectric thin film element having such a structure is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then ITO is used as a first layer material layer of a lower electrode by sputtering to form 0.05 to 0. A lower electrode made of Pt containing 5 to 80% of Bi by a Pt target containing 5 to 80% of Bi in atomic ratio or a binary sputtering method using a Pt target and Bi target. A second material layer of 0.2 to 0.5 μm was formed. Subsequently, a high ferroelectric film material layer was formed into a film of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Further, an upper electrode material layer made of Pt containing 5 to 80% of Bi was sputtered thereon by a Pt target containing 5 to 80% of Bi in atomic ratio or a binary sputtering method using a Pt target and a Bi target. 0.2 to 0.
A film having a thickness of 4 μm was formed. After that, ion milling or RI
Using E, an upper electrode material layer, a high and a ferroelectric film material layer, and a lower electrode material layer are sequentially formed into a predetermined shape, and finally 6
A heat treatment at a temperature of 00 to 800 ° C. is applied to form a lower electrode composed of an upper electrode 56, a high ferroelectric film 55, and a first layer 54a and a second layer 54b.
54 was formed, and a dielectric thin film element was manufactured.

According to the thirteenth embodiment, like the eleventh embodiment,
As a result of performing elemental analysis in the depth direction by XPS for the conventional upper electrode, the device including only Pt as the lower electrode, and the device of the example, in the conventional device, Bi in the ferroelectric film was high, and In the element of Example 13, no such diffusion was observed, while the diffusion to Pt of the electrode was observed, and a high composition change occurred at the interface between the upper electrode 56 and the lower electrode 54 of the ferroelectric film 55. Didn't. Further, the upper electrode 56 and the lower electrode 54 had a composition such as Bi ₂ Pt or BiPt.

Therefore, also in the element of the thirteenth embodiment, similarly to the eighth embodiment, the withstand voltage of 10 V or more is exhibited, and the dielectric constant is 300 or more, which is improved by 20% or more as compared with the conventional one.

When the high ferroelectric film 55 contains Sr, Bi is used as the second layer of the upper electrode and the lower electrode.
Similar results were obtained by using Pt containing and Sr. In addition, in Pt containing Bi, the atomic ratio of B is
With the composition of i: Pt = 2: 1 or 1: 1, the dielectric thin film element with the best characteristics was obtained.

Further, by using ITO as the first layer of the lower electrode, the adhesiveness with the lower layer is improved, and it becomes possible to prevent the peeling of the film, which is a problem in the conventional element.
Higher constituent elements (such as Si) in the lower layer, diffusion into the ferroelectric film,
And, it has become possible to prevent the diffusion of the constituent elements of the high and ferroelectric films to the lower layers.

(Embodiment 14) FIG. 8 shows Embodiment 14 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIGS. 5 and 7 are designated by the same reference numerals and the description thereof will be omitted. Example 14 is
Compared to the seventh embodiment, the lower electrode 54 and the upper electrode 56 are the same in that they have three layers and two layers, respectively.
The configurations of the ferroelectric film 55 and the upper electrode 56 are different from each other. That is, the lower electrode 54 is made of ITO and has a thickness of 0.05-0.
4 μm of the first layer 54a and a thickness of 0.2 to 0.
4 μm second layer 54b and Pt containing 5-80% Bi
And a third layer 54c having a thickness of 0.2 to 0.4 μm. Further, the high and ferroelectric film 55 has a thickness of 0.2 to
It is a 0.5 μm Bi layered ferroelectric film, and the upper electrode 56 is made of Pt containing 5 to 80% of Bi and has a thickness of 0.2 to
The first layer 56a has a thickness of 0.4 μm, and the second layer 56b made of Pt and having a thickness of 0.2 to 0.4 μm is formed on the first layer 56a.

The dielectric thin film element thus constructed is manufactured as follows. First, a thermally oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then ITO is formed.
Is formed into a first layer of the lower electrode by sputtering with a thickness of 0.0
A material layer having a thickness of 5 to 0.4 μm is formed, and Pt is sputtered thereon to form a second layer of the lower electrode having a thickness of 0.2 to 0.4.
A Pt target containing 5 to 50% by weight of Rh, or a binary sputtering method using a Pt target and a Rh target, was used to form Pt containing 5 to 50% of Bi. And a material layer to be the third layer of the lower electrode was formed to a thickness of 0.2 to 0.4 μm. Next, spin coating of high and ferroelectric material layers, CV
After forming a film of 0.2 to 0.5 μm with D or the like, 600 to 80
Heat treatment was performed at 0 ° C. Subsequently, a Pt target or P containing Bi in an atomic ratio of 5 to 80%
By a binary sputtering method using a t target and a Bi target, a material layer having a thickness of 0.2 to 0.4 μm, which is a first layer of an upper electrode made of Pt containing 5 to 80% of Bi, is formed, Further thereon, a material layer having a thickness of 0.2 to 0.4 μm, which is a second layer of the upper electrode made of Pt, was formed by sputtering. Then, each material layer of the upper electrode material layer, high and ferroelectric film material layers and each material layer of the lower electrode are sequentially formed into a predetermined shape by using ion milling or RIE, and finally at 600 to 800 ° C. Heat treated, first layer
An upper electrode 56 composed of 56a and a second layer 56b, a high ferroelectric film 55, and a lower electrode 54 composed of a first layer 54a, a second layer 54b and a third layer 54c were formed to manufacture a dielectric thin film element. .

According to the fourteenth embodiment, like the eleventh embodiment,
As a result of performing elemental analysis in the depth direction by XPS for the conventional upper electrode, the device including only Pt as the lower electrode, and the device of the example, in the conventional device, Bi in the ferroelectric film was high, and Whereas in the element of Example 14, such diffusion was not observed, while the diffusion to Pt of the electrode was observed, and a composition change occurred at the interface between the upper electrode 56 and the lower electrode 54 of the high ferroelectric film 55. Didn't. Further, the upper electrode 56 and the lower electrode 54 had a composition such as Bi ₂ Pt or BiPt.

Therefore, also in the element of the fourteenth embodiment, similarly to the eighth embodiment, the withstand voltage of 10 V or more is exhibited, and the dielectric constant is 300 or more, which is improved by 20% or more as compared with the conventional one.

When the high ferroelectric film 55 contains Sr, Pt containing Bi and Sr should be used as the third layer 54c of the lower electrode 54 and the first layer 56a of the upper electrode 56. With similar results. In addition, Pt containing Bi
In the atomic ratio, Bi: Pt = 2: 1 or 1: 1
With the above composition, a ferroelectric thin film element having the best characteristics was obtained. This also applies to the other embodiments.

(Embodiment 15) FIG. 5 shows Embodiment 15 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In the fifteenth embodiment, as compared with the first embodiment, the upper electrode 56 has the same structure and the lower electrode
54 and the high and ferroelectric films 55 have different configurations. That is, the lower electrode 54 is an electrode made of Pt containing 5 to 50% of Rh and 5 to 80% of Bi and having a thickness of 0.2 to 0.4 .mu.m. Bi of 2 to 0.5 μm
It is a layered ferroelectric film.

The dielectric thin film element thus constructed is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and Rh is added thereto in a weight ratio of 5 to 50% and Bi in an atomic ratio of 5 to 50%.
By a ternary sputtering method using a Pt target containing 80% or a Pt target, a Rh target, and a Bi target, Rh is 5 to 50% and Bi is 5 to 8%.
A lower electrode material layer made of Pt containing 0% of 0.2 to
A film having a thickness of 0.4 μm was formed. Subsequently, a high and ferroelectric film material layer is applied by spin coating, CVD, etc.
After the film formation, a heat treatment at 600 to 800 ° C. was performed.
Subsequently, an upper electrode material layer made of Pt was formed thereon by sputtering to a thickness of 0.2 to 0.4 μm. afterwards,
By using ion milling or RIE, the upper electrode material layer, the high and ferroelectric film material layers and the lower electrode material layer are sequentially formed into a predetermined shape to form an upper electrode 56, a high and ferroelectric film 55, and a lower electrode 54. Then, a dielectric thin film element was manufactured.

According to the fifteenth embodiment, when the surface of the lower electrode 54 is observed by SEM, the crystal grains are small and uniform at about 50 nm, and when scratched with a diamond indenter having a radius of curvature of 10 μm, the conventional Pt In contrast, since the film had ductility, scratches were generated under a load of 10 mN or less, whereas the electrode of Example 15 was a hard film without scratches even at 50 mN. Therefore, when heat treatment was performed at 600 to 800 ° C. after forming the lower electrode material layer, many hillocks having a height of 0.1 μm or more were generated on the surface of the conventional Pt, while the hillocks of the electrode of Example 15 were formed. No abnormal precipitates such as the above were generated, and there was no change on the electrode surface before and after the heat treatment.

Further, elemental analysis in the depth direction by XPS was performed on the conventional Pt-only element as the lower electrode and the element of Example 15 as a result.
Bi diffused into Pt of the lower electrode 54, whereas no such diffusion was observed in the element of Example 15,
High, no composition change occurred at the interface of the lower electrode 54 of the ferroelectric film 55. Further, the lower electrode 54 had a composition such as Bi ₂ Pt or BiPt.

Therefore, in the conventional Bi layered ferroelectric thin film element, when a voltage is applied between the upper electrode and the lower electrode,
The dielectric breakdown voltage was about 5 V because the electric field was concentrated on the hillocks, whereas it was 10 in the dielectric thin film element of Example 15.
It showed a withstand voltage of V or more. Further, in the conventional element, the withstand voltage depends on the element area, and the higher the element area, the lower the withstand voltage. However, in the element of Example 15, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleus generation is uniform during the heat treatment of the high ferroelectric film, and good nucleus growth without defects is performed.

Further, the dielectric constant of the conventional element is about 250, whereas the dielectric constant of the element of the embodiment is 300 or more, which is an improvement of 20% or more.

As the lower electrode, instead of Rh, R
At least one element selected from h, Ru, Ir, and Os may be contained, and when the Bi layered ferroelectric film contains Sr, the same result was obtained even if Sr was contained.

(Embodiment 16) FIG. 5 shows Embodiment 16 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Example 16 differs from Example 1 in the configurations of the lower electrode 54, the high ferroelectric film 55, and the upper electrode 56. That is, the lower electrode 54 has Rh of 5 to 5
An electrode having a thickness of 0.2 to 0.4 μm and made of Pt containing 50% and 5 to 80% Bi, and the high ferroelectric film 55 is a Bi layered ferroelectric having a thickness of 0.2 to 0.5 μm. Is the body membrane,
The upper electrode 56 is an electrode made of Pt containing 5 to 50% of Rh and 5 to 80% of Bi and having a thickness of 0.2 to 0.4 μm.

The dielectric thin film element having the above structure is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and Rh is added thereto in a weight ratio of 5 to 50% and Bi in an atomic ratio of 5 to 50%.
By a ternary sputtering method using a Pt target containing 80% or a Pt target, a Rh target, and a Bi target, Rh is 5 to 50% and Bi is 5 to 8%.
A lower electrode material layer made of Pt containing 0% of 0.2 to
A film having a thickness of 0.4 μm was formed. Subsequently, a high and ferroelectric film material layer is applied by spin coating, CVD, etc.
After the film formation, a heat treatment at 600 to 800 ° C. was performed.
Subsequently, Rh of 5 to 5% is formed by a Pt target containing 5 to 50% by weight of Rh and 5 to 80% of Bi in atomic ratio, or a ternary sputtering method using a Pt target, a Rh target, and a Bi target. An upper electrode material layer made of Pt containing 50% and Bi of 5 to 80% was formed to a thickness of 0.2 to 0.4 μm. Then, using ion milling or RIE, the upper electrode material layer, high,
A ferroelectric film material layer and a lower electrode material layer are sequentially formed into a predetermined shape, and finally heat-treated at 600 to 800 ° C. to form an upper electrode 56, a high ferroelectric film 55, and a lower electrode 54, Dielectric thin film element was manufactured.

According to the sixteenth embodiment, as in the fifteenth embodiment,
SEM observation of the surface of the lower electrode 54 revealed that the crystal grains were 5
It is as small as 0 nm and uniform, and has a radius of curvature of 10
When scratching the surface with a diamond indenter of μm,
The conventional Pt had a ductility and therefore scratches were generated under a load of 10 mN or less, whereas the electrode of Example 15 was a hard film without scratches even at 50 mN. Therefore, after forming the lower electrode 103, 600 to 800
When heat treatment was performed at ℃, conventional Pt generated many hillocks with a height of 0.1 μm or more on the surface.
In the electrode of Example 15, no abnormal deposit such as hillock was generated, and there was no change in the electrode surface before and after the heat treatment. Further, also at the interface between the upper electrode 56 and the high ferroelectric film 54, no abnormal deposit such as hillock was generated after the final heat treatment. Further, as a result of performing elemental analysis in the depth direction by XPS on the conventional Pt-only element and the element of the example as the upper and lower electrodes, in the conventional element, Bi in the Bi-layered ferroelectric film is the upper and lower electrodes. While diffused in Pt, no such diffusion is observed in the device of the example,
High, no composition change occurred at the interface between the upper electrode 56 and the lower electrode 54 of the ferroelectric film 54. Further, the upper electrode 56 and the lower electrode 54 had a composition such as Bi ₂ Pt or BiPt.

Therefore, in the conventional element, when the voltage was applied between the upper and lower electrodes and the lower electrode, the withstand voltage was about 5 V because the electric field was concentrated on the hillocks, whereas the dielectric thin film of Example 16 was used. The device showed a withstand voltage of 10 V or higher. Further, in the conventional element, the withstand voltage depends on the element area, and the larger the element area, the lower the withstand voltage. However, in the element of Example 16, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleus generation during the heat treatment of the Bi layered ferroelectric film is uniform and good nucleus growth without defects is performed.

The dielectric constant of the conventional element is about 25.
While the value is 0, the element of Example 16 has a value of 300 or more, which is an improvement of 20% or more.

(Embodiment 17) FIG. 6 shows Embodiment 17 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIG. In Example 17, as compared with Example 3, the upper electrode 56 has the same structure, but the lower electrode 54
And the structure of the high and ferroelectric films 54 is different. That is, the lower electrode
54 is a first layer 54 made of Pt and having a thickness of 0.2 to 0.4 μm.
and a second layer 54b made of Pt containing 5 to 50% of Rh and 5 to 80% of Bi. Also,
The high ferroelectric film 54 is a Bi layered ferroelectric film having a thickness of 0.2 to 0.5 μm.

The dielectric thin film element thus constructed is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then a material layer to be a first layer of a lower electrode is formed by sputtering Pt.
Pt having a film thickness of 2 to 0.4 μm and further containing Rh in an amount of 5 to 50% by weight and Bi in an amount of 5 to 80% by atomic ratio
Target or Pt target, Rh target,
Rh by the ternary sputtering method using a Bi target
5 to 50% of Bi and 5 to 80% of Bi, and a material layer to be the second layer of the lower electrode made of Pt is 0.2 to 0.4 μm.
A film was formed. Subsequently, a high ferroelectric film material layer was formed to a thickness of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Subsequently, an upper electrode material layer made of Pt was formed to a thickness of 0.2 to 0.4 μm by sputtering. After that, the upper electrode material layer, the high and ferroelectric film material layers and the lower electrode material layer are sequentially formed into a predetermined shape by using ion milling or RIE, and the upper electrode 56, the high and ferroelectric film 55 and the lower portion are formed. The electrode 54 was formed, and the dielectric thin film element was manufactured.

When the surface of the second layer 54b of the lower electrode 54 of Example 17 was observed by SEM, the crystal grains were small and uniform at about 50 nm, and when the surface was scratched with a diamond indenter having a radius of curvature of 10 μm, Since Pt had ductility, scratches were generated under a load of 10 mN or less, whereas the electrode of the example was a hard film without scratches even at 50 mN. Therefore, after performing the heat treatment at 600 to 800 ° C. after forming the lower electrode,
In the conventional Pt, many hillocks having a height of 0.1 μm or more were generated on the surface, whereas in the electrode of Example 17, no abnormal deposits such as hillocks were generated and the electrode surface did not change before and after the heat treatment. It was

In addition, as a result of elemental analysis in the depth direction by XPS for the conventional Pt-only element as the lower electrode and the element of Example 17, as a result of the conventional element, Bi in the Bi layered ferroelectric film is lower than the lower electrode. While diffused in Pt of the electrode, no such diffusion was observed in the element of Example 17,
High, no composition change occurred at the interface of the second electrode 54b of the lower electrode 54 of the ferroelectric film 55. Further, the lower electrode 54 is made of Bi ₂
A composition such as Pt or BiPt was shown.

Therefore, in the conventional device, when the voltage is applied between the upper and lower electrodes, the withstand voltage was about 5 V because the electric field was concentrated on the hillocks, whereas in the dielectric thin film device of Example 17, it was 10 V. The above dielectric strength is shown. In the conventional element, the withstand voltage depends on the element area, and the higher the element area, the lower the withstand voltage. However, in the element of Example 17, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleus generation during the heat treatment of the Bi layered ferroelectric film is uniform and good nucleus growth without defects is performed.

The dielectric constant of the conventional device is about 250, while that of the embodiment! 3 in 17 elements
It is more than 00 and improved by 20% or more.

As the second layer of the lower electrode, at least one element selected from Rh, Ru, Ir and Os may be contained instead of Rh.
When Sr was contained, similar results were obtained even when Sr was contained.

Furthermore, the Pt electrode containing at least one element of Rh, Ru, Ir, and Os and Bi or Bi and Sr tends to have higher electric resistance than the Pt electrode, but the lower electrode By lining with a Pt electrode as the first layer of, the same electric resistance as the electrode of the conventional device was obtained. This also applies to the other embodiments.

(Embodiment 18) FIG. 7 shows Embodiment 18 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIG. Example 18 is different from Example 4 in that the lower electrode 54, the high ferroelectric film 55, and the upper electrode.
56 configurations are different. That is, the lower electrode 54 comprises a Pt first layer 54a having a thickness of 0.2 to 0.4 μm and Rh of 5 to 5 μm.
Second layer consisting of Pt containing 0% and 5-80% Bi
It is composed of 54b. In addition, the high, ferroelectric film 55 is
It is a Bi layered ferroelectric film having a thickness of 0.2 to 0.5 μm.
Further, the upper electrode 56 has Rh of 5 to 50% and Bi of 5 to 5%.
It is composed of a first layer 56a made of Pt containing 80% and having a thickness of 0.2 to 0.4 μm, and a second layer 56b made of Pt and having a thickness of 0.2 to 0.4 μm formed thereon. ing.

The dielectric thin film element having the above structure is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then a material layer to be a first layer of a lower electrode is formed by sputtering Pt.
Pt having a film thickness of 2 to 0.4 μm and further containing Rh in an amount of 5 to 50% by weight and Bi in an amount of 5 to 80% by atomic ratio
Target or Pt target, Rh target,
Rh by the ternary sputtering method using a Bi target
5 to 50% of Bi and 5 to 80% of Bi, and a material layer to be the second layer of the lower electrode made of Pt is 0.2 to 0.4 μm.
A film was formed. Subsequently, a high ferroelectric film material layer was formed to a thickness of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Continuing, a Pt target containing 5 to 50% by weight of Rh and 5 to 80% of Bi in atomic ratio was used, or a Pt target, a Rh target, and a Bi target were used.
By the original sputtering method, a material layer to be the first layer of the upper electrode made of Pt containing Rh in an amount of 5 to 50% and Bi in an amount of 5 to 80% was formed in a thickness of 0.2 to 0.4 μm, and Pt was formed thereon. The material layer to be the second layer of the upper electrode is formed to a thickness of 0.2 to 0.4 μm by sputtering. Then, using ion milling or RIE, the upper electrode material layer, the high and ferroelectric film material layers, and the lower electrode material layer are sequentially formed into a predetermined shape, and finally heat-treated at 600 to 800 ° C. to form the upper electrode. 56, a high ferroelectric film 55 and a lower electrode 54 were formed to manufacture a dielectric thin film element.

SEM observation of the surface of the second layer 54b of the lower electrode 54 of Example 18 revealed that the crystal grains were as small as 50 nm and were uniform, and that when scratched with a diamond indenter having a radius of curvature of 10 μm, Since Pt had ductility, scratches were generated under a load of 10 mN or less, whereas the electrode of the example was a hard film without scratches even at 50 mN. Therefore, when heat treatment is performed at 600 to 800 ° C. after forming the lower electrode,
In the conventional Pt, a large number of hillocks having a height of 0.1 μm or more were generated on the surface, whereas in the electrode of Example 18, no abnormal deposits such as hillocks were generated and the electrode surface did not change before and after the heat treatment. It was Further, also at the interface between the upper electrode 56 and the high ferroelectric film 55, no abnormal precipitate such as hillock was generated after the final heat treatment.

Also, as conventional upper and lower electrodes, P
As a result of performing an elemental analysis in the depth direction by XPS on the element having only t and the element of Example 18, Bi in the Bi layered ferroelectric film was diffused into Pt of the upper electrode and the lower electrode in the conventional element. On the other hand, in the device of Example 18, no such diffusion was observed, and no change in composition occurred at the interface between the upper and lower electrodes 56 and 54 of the ferroelectric film 55. Further, the first layer 56a of the upper electrode 56 and the second layer 54 of the lower electrode 54
b has a composition such as Bi ₂ Pt or BiPt.

Therefore, in the conventional element, when the voltage is applied to the upper electrode and the lower electrode, the withstand voltage is about 5 V because the electric field is concentrated on the hillock, whereas the Bi ferroelectric material of Example 18 is used. The device showed a withstand voltage of 10 V or higher. Further, in the conventional element, the withstand voltage depends on the element area, and the higher the element area, the lower the withstand voltage. However, in the element of Example 18, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleation of the Bi layered ferroelectric film during the heat treatment is uniform and good nucleation without defects is performed.

The dielectric constant of the conventional device is about 250, while that of the device of Example 18 is 30.
It became 0 or more and improved by 20% or more.

As the second layer of the lower electrode and the first layer of the upper electrode, at least one element selected from Rh, Ru, Ir and Os may be contained instead of Rh. When the film contained Sr, similar results were obtained even when Sr was contained. This also applies to the other embodiments.

Example 19 FIG. 2 shows Example 19 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIG. Example 19 differs from Example 3 in the configurations of the lower electrode 54 and the high and ferroelectric film 55. That is, the lower electrode 54 is made of ITO and has a thickness of 0.0
It is composed of a first layer 54a having a thickness of 5 to 0.4 μm and a second layer 54b made of Pt containing 5 to 50% of Rh and 5 to 80% of Bi. The high and ferroelectric film 55 has a thickness of 0.
It is a Bi-layered ferroelectric film having a thickness of 2 to 0.5 μm.

The dielectric thin film element having the above structure is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then a material layer serving as a first layer of a lower electrode is formed to have a thickness of 0.2 to 0.4 μm by using ITO. By a Pt target containing Rh in an amount of 5 to 50% by weight and Bi in an amount of 5 to 80% in an atomic ratio, a ternary sputtering method using a Pt target, a Pt target, a Rh target, and a Bi target is performed.
The material layer to be the second layer of the lower electrode made of Pt containing 5 to 50% of Rh and 5 to 80% of Bi is 0.2 to 0.4.
A μm film was formed. Subsequently, a high ferroelectric film material layer was formed to a thickness of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Subsequently, an upper electrode material layer of Pt was sputtered thereon to form a film of 0.2 to 0.4 μm. Then, using ion milling or RIE, the upper electrode material layer, high,
A ferroelectric film material layer and a lower electrode material layer are sequentially formed in a predetermined shape to form an upper electrode 56, a high ferroelectric film 55, and a lower electrode.
54 was formed, and a dielectric thin film element was manufactured.

SEM observation of the surface of the second layer 54b of the lower electrode 54 of Example 19 revealed that the crystal grains were small and uniform, about 50 nm, and the surface was scratched with a diamond indenter having a radius of curvature of 10 μm. Since Pt had ductility, scratches were generated under a load of 10 mN or less, whereas the electrode of Example 19 was a hard film without scratches even at 50 mN. Therefore, when heat treatment was performed at 600 to 800 ° C. after forming the lower electrode, many hillocks having a height of 0.1 μm or more were generated on the surface of the conventional Pt, whereas hillocks and the like of the electrode of Example 19 were generated. No abnormal precipitate was generated, and there was no change on the electrode surface before and after the heat treatment.

Further, as a result of elemental analysis in the depth direction by XPS of the conventional Pt-only device as the lower electrode and the device of Example 19, as a result of the conventional device, Bi in the Bi-layered ferroelectric film is at the lower part. While diffused in Pt of the electrode, no such diffusion was observed in the element of Example 19,
High, no composition change occurred at the interface of the lower electrode 54 of the ferroelectric film 55. Further, in the case where the lower electrode 54 is only conventional Pt, Si, which is the element of the thermally oxidized SiO ₂ film 53 and causes the deterioration of the characteristics of the ferroelectric film, has diffused to the Pt surface. It was found that in the structures of the examples, ITO acts as a diffusion barrier and prevents the diffusion of Si.

Therefore, in the conventional element, when the voltage was applied between the upper electrode and the lower electrode, the withstand voltage was about 5 V because the electric field was concentrated on the hillocks, whereas the dielectric thin film of Example 19 was used. The device showed a withstand voltage of 10 V or higher. Further, in the conventional element, the withstand voltage depends on the element area, and the higher the element area, the lower the withstand voltage. However, in the element of Example 19, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleation of the Bi layered ferroelectric film during the heat treatment is uniform and good nucleation without defects is performed.

The dielectric constant of the conventional device is about 250, while that of the device of Example 19 is 30.
It became 0 or more and improved by 20% or more.

Furthermore, by using ITO as the first layer of the lower electrode, the adhesiveness with the lower layer is improved, and the peeling of the film, which is a problem in the conventional element, can be prevented.
Higher constituent elements (such as Si) in the lower layer, diffusion into the ferroelectric film,
Further, it has become possible to prevent the diffusion of the constituent elements of the high ferroelectric film to the lower layer.

(Embodiment 20) FIG. 6 shows Embodiment 20 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIG. Example 20 is different from Example 3 in the configurations of the lower electrode 54, the high, ferroelectric film 55, and the upper electrode. That is, the lower electrode 54 comprises a first layer 54a made of ITO and having a thickness of 0.05 to 0.4 μm, and Rh of 5 to 5.
The second layer 54b is composed of Pt containing 50% and Bi of 5 to 80%. Also, high, ferroelectric film 55
Is a Bi layered ferroelectric film having a thickness of 0.2 to 0.5 μm. Further, the upper electrode 56 is an electrode made of Pt containing 5 to 50% of Rh and 5 to 80% of Bi.

The dielectric thin film element thus constructed is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then a material layer serving as a first layer of a lower electrode is formed to have a thickness of 0.2 to 0.4 μm by using ITO. By a Pt target containing Rh in an amount of 5 to 50% by weight and Bi in an amount of 5 to 80% in an atomic ratio, a ternary sputtering method using a Pt target, a Pt target, a Rh target, and a Bi target is performed.
The material layer to be the second layer of the lower electrode made of Pt containing 5 to 50% of Rh and 5 to 80% of Bi is 0.2 to 0.4.
A μm film was formed. Subsequently, a high ferroelectric film material layer was formed to a thickness of 0.2 to 0.5 μm by spin coating, CVD or the like, and then heat treatment was performed at 600 to 800 ° C. Continuing, a Pt target or P containing Rh in an amount of 5 to 50% by weight and Bi in an amount of 5 to 80% in atomic ratio.
By the ternary sputtering method using a t target, a Rh target and a Bi target, Rh is 5 to 50% and B
An upper electrode material layer made of Pt containing 5 to 80% of i was formed to a thickness of 0.2 to 0.4 μm. Then, using ion milling or RIE, the upper electrode material layer, the high and ferroelectric film material layers, and the lower electrode material layer are sequentially formed into a predetermined shape, and finally heat-treated at 600 to 800 ° C. to form the upper electrode.
56, a high ferroelectric film 55 and a lower electrode 54 were formed to manufacture a dielectric thin film element.

SEM observation of the surface of the second layer 54b of the lower electrode 54 of Example 20 revealed that the crystal grains were as small as 50 nm and were uniform, and that when the surface was scratched with a diamond indenter having a radius of curvature of 10 μm, Since Pt had ductility, scratches were generated under a load of 10 mN or less, whereas the electrode of Example 20 was a hard film without scratches even at 50 mN. Therefore, when heat treatment was performed at 600 to 800 ° C. after forming the lower electrode 54, many hillocks having a height of 0.1 μm or more were generated on the surface of the conventional Pt, whereas hillocks and the like were generated in the electrode of Example 20. No abnormal precipitates were generated, and there was no change on the electrode surface before and after the heat treatment. Further, also at the interface between the upper electrode 56 and the high ferroelectric film 55, no abnormal deposit such as hillock was generated after the final heat treatment.

Further, as conventional upper and lower electrodes, P
As a result of performing elemental analysis in the depth direction by XPS on the element having only t and the element of Example 20, in the conventional element, Bi in the Bi layered ferroelectric film was diffused into Pt of the upper electrode and the lower electrode. On the other hand, in the device of Example 20, such diffusion was not observed, and the composition change at the interface between the upper and lower electrodes 56 and 54 of the ferroelectric film 55 did not occur. Furthermore, when the lower electrode is only conventional Pt, thermal oxidation S
In the structure of the example, ITO acts as a diffusion barrier, and Si, which is an element of the iO ₂ film 53, has been diffused to the surface of Pt, which causes deterioration of the characteristics of the ferroelectric film. It turns out that it is preventing.

Therefore, in the conventional element, when the voltage was applied between the upper electrode and the lower electrode, the withstand voltage was about 5 V because the electric field was concentrated on the hillock, whereas the dielectric thin film of Example 20 was used. The device showed a withstand voltage of 10 V or higher. In the conventional element, the withstand voltage depends on the element area, and the larger the element area, the lower the withstand voltage. However, in the element of Example 20, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleation of the Bi layered ferroelectric film during the heat treatment is uniform and good nucleation without defects is performed.

Further, the dielectric constant of the conventional element is about 250, whereas the dielectric constant of the element of the embodiment is 300 or more, which is improved by 20% or more.

Furthermore, by using ITO as the first layer of the lower electrode, the adhesiveness with the lower layer is improved, and the peeling of the film, which was a problem in the conventional element, can be prevented.
Higher constituent elements (such as Si) in the lower layer, diffusion into the ferroelectric film,
Further, it has become possible to prevent the diffusion of the constituent elements of the high ferroelectric film to the lower layer.

(Embodiment 21) FIG. 8 shows Embodiment 21 of the present invention.
This will be described with reference to the sectional structure diagram of FIG. However, the same members as those in FIG. Example 21 is different from Example 7 in that the lower electrode 54, the high ferroelectric film 55, and the upper electrode.
56 configurations are different. That is, the lower electrode 54 includes a first layer 54a made of ITO and having a thickness of 0.05 to 0.4 μm, a second layer 54b made of Pt and having a thickness of 0.2 to 0.4 μm, and Rh of 5
The third layer 54c is composed of Pt containing 50% to 50% of Bi and 5% to 80% of Bi. Also, high, ferroelectric film 55
Is a Bi layered ferroelectric film having a thickness of 0.2 to 0.5 μm. Further, the upper electrode 56 is composed of a first layer 56a made of Pt containing 5 to 50% of Rh and 5 to 80% of Bi, and a second layer 56b made of Pt and having a thickness of 0.2 to 0.4 μm. To be done.

The dielectric thin film element thus constructed is manufactured as follows. First, a thermally-oxidized SiO ₂ film 53 is formed as a lower layer of a dielectric thin film element on a Si substrate 53, and then a material layer to be a first layer of a lower electrode is sputtered with ITO to form a first layer.
2 to 0.4 μm is formed, a material layer to be the second layer of the lower electrode is formed thereon by sputtering to a thickness of 0.2 to 0.4 μm, and Rh is further formed thereon in a weight ratio of 5 to 50 μm. % And Bi in an atomic ratio of 5 to 80%, or a Pt target, a Pt target, a Rh target, and a ternary sputtering method using a Bi target, from Pt containing 5 to 50% of Rh and 5 to 80% of Bi. A material layer to be the third layer of the lower electrode is formed to a thickness of 0.2 to 0.4 μm. Next, spin coating high and ferroelectric film material layers,
After forming a film of 0.2 to 0.5 μm by CVD, etc., 600 to
A heat treatment at 800 ° C. was performed. Continue to R on it
h is 5 to 50% by weight and Bi is 5 to 80 by atomic ratio.
% Pt target or Pt target, R
By a three-way sputtering method using an h target and a Bi target, a material layer serving as the first layer of the upper electrode made of Pt containing Rh in an amount of 5 to 50% and Bi in an amount of 5 to 80% is 0.2 to 0.4 μm. A film is formed, and a material layer to be the second layer of the upper electrode made of Pt is further formed thereon by sputtering.
A film having a thickness of 2 to 0.4 μm was formed. Then, using ion milling or RIE, the upper electrode material layer, the high and ferroelectric film material layers, and the lower electrode material layer are sequentially formed into a predetermined shape,
Finally, heat treatment at 600 to 800 ° C. is performed to form an upper electrode 56 composed of a first layer 56a and a second layer 56b, a high ferroelectric film 55,
A lower electrode 54 composed of a first layer 54a, a second layer 54b and a third layer 54c was formed to manufacture a ferroelectric thin film element.

SEM observation of the surface of the third layer 54c of the lower electrode 54 of Example 21 revealed that the crystal grains were small and uniform, about 50 nm, and that when scratched with a diamond indenter having a radius of curvature of 10 μm, In Pt, because of ductility, scratches were generated under a load of 10 mN or less, whereas in the electrode of Example 21, scratches were not generated even at 50 mN and the film was a hard film. Therefore, when heat treatment was performed at 600 to 800 ° C. after forming the lower electrode 54, many hillocks having a height of 0.1 μm or more were generated on the surface of the conventional Pt, whereas hillocks and the like were generated in the electrode of Example 21. No abnormal precipitates were generated, and there was no change on the electrode surface before and after the heat treatment. Further, also at the interface between the upper electrode 56 and the high ferroelectric film 55, no abnormal deposit such as hillock was generated after the final heat treatment.

Further, as conventional upper and lower electrodes, P
As a result of performing elemental analysis in the depth direction by XPS on the device having only t and the device of Example 21, in the conventional device, Bi in the Bi layered ferroelectric film was diffused into Pt of the upper electrode and the lower electrode. On the other hand, in the device of Example 21, such diffusion was not observed, and the composition change at the interface between the upper and lower electrodes 56 and 54 of the ferroelectric film 55 did not occur. Furthermore, when the lower electrode is only conventional Pt, thermal oxidation S
In the element of the iO ₂ film 53, Si which causes the deterioration of the characteristics of the ferroelectric film was diffused to the Pt surface, whereas in the structure of Example 21, ITO acts as a diffusion barrier and the diffusion of Si. It turned out that it is preventing.

Therefore, in the conventional element, when the voltage is applied between the upper electrode and the lower electrode, the withstand voltage is about 5 V because the electric field is concentrated on the hillock, whereas the dielectric thin film of Example 21 is used. The device showed a withstand voltage of 10 V or higher. Further, in the conventional element, the withstand voltage depends on the element area, and the larger the element area, the lower the withstand voltage. However, in the element of Example 21, the withstand voltage does not depend on the element area and is constant. Since the values are shown, it can be said that the nucleus generation is uniform during the heat treatment of the high ferroelectric film, and good nucleus growth without defects is performed.

Further, the dielectric constant of the conventional element is about 250, whereas that of the element of the embodiment is 300 or more, which is an improvement of 20% or more.

Further, by using ITO as the first layer of the lower electrode, the adhesiveness with the lower layer is improved, and the peeling of the film, which is a problem in the conventional element, can be prevented, and the constituent elements of the lower layer ( It has become possible to prevent the diffusion of (Si, etc.) into the ferroelectric film and the diffusion of the constituent elements of the ferroelectric film into the lower layer.

As the second layer of the lower electrode and the first layer of the upper electrode, at least one element selected from Rh, Ru, Ir, and Os may be contained instead of Rh. When the film contained Sr, similar results were obtained even when Sr was contained.

The above description is based on the embodiment.
The present invention includes the following inventions.

1. In a dielectric thin film element having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film, Lower electrode is Rh, Ru, Os, Ir
A dielectric thin film element comprising Pt containing at least one element of Pt.

[Structure] The present invention corresponds to the first embodiment. In the first embodiment, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline silicon (Si) layer, or a semiconductor diffusion region, and Rh, Ru, and O as lower electrodes 54 are formed on the lower layer 53.
Pt containing at least one element of s and Ir is formed, a high ferroelectric film 55 is formed thereon, and Pt is formed thereon as an upper electrode 56. .

[Operation] As the lower electrode 54, Rh, Ru,
Pt containing at least one element of Os and Ir
By using Pt, the ductility of Pt is reduced to increase the rigidity, and the crystal grain size is reduced to reduce the variation in the crystal grain size. As a result, hillocks are not generated on the surface of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or more, the flatness is maintained, and the nucleus growth during the heat treatment of the high ferroelectric film 55 is performed well. Therefore, the occurrence of defects is suppressed.

[Effects] Since no abnormal deposits such as hillocks are present on the surface of the lower electrode 54, the upper electrode 56, the lower electrode
Since it is possible to prevent the electric field concentration that occurs when a voltage is applied between 54, it is possible to improve the dielectric strength and fatigue resistance. Further, since the crystal grain size of the lower electrode 54 is small and has little variation, and there is no hillock, it is possible to obtain a high ferroelectric film.
Since nuclei are uniformly generated during the heat treatment of 55 and favorable nuclei growth is performed, a high-defect and high-strength ferroelectric film 55 can be formed. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength, fatigue resistance, and dielectric constant.

2. The lower electrode and the upper electrode are Rh, R
1. It is composed of Pt containing at least one element of u, Os and Ir. The dielectric thin film element described.

[Structure] The present invention corresponds to the second embodiment. In the second embodiment, the lower layer 52 of the dielectric thin film element is formed on the substrate 51. This lower layer 52 is an insulating film, polycrystalline S
The i-layer or the semiconductor diffusion region corresponds to the lower layer 52
A Pt containing at least one element of Rh, Ru, Os, and Ir is formed on the lower electrode 54, a high ferroelectric film 55 is formed on the Pt, and Rh is formed on the upper electrode 55 as the upper electrode 55. , Ru, Os, Ir, Pt containing at least one element is formed.

[Operation] As the lower electrode 54, Rh, Ru,
Pt containing at least one element of Os and Ir
By using Pt, the ductility of Pt is reduced to increase the rigidity, and the crystal grain size is reduced to reduce the variation in the crystal grain size. As a result, hillocks are not generated on the surface of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or more, the flatness is maintained, and the nucleus growth during the heat treatment of the high ferroelectric film 55 is performed well. Therefore, the occurrence of defects is suppressed. Furthermore, by using Pt containing at least one element of Rh, Ru, Os, and Ir also for the upper electrode 56, even if a heat treatment at 600 ° C. or higher is performed after the formation of the upper electrode 56, a high ferroelectric substance can be obtained. It is possible to prevent abnormal deposits such as hillocks from being generated at the interface between the film 55 and the lower electrode 54 and the upper electrode 56.

[Effects] High, ferroelectric film 55 and lower electrode 54
Since no abnormal deposits such as hillocks are present at the interface between the upper electrode 56 and the upper electrode 56, it is possible to prevent electric field concentration that occurs when a voltage is applied between the upper electrode 56 and the lower electrode 54, so that the dielectric strength and fatigue resistance can be improved. be able to. Furthermore, since the crystal grain size of the lower electrode 54 is small and the variation is small, and there is no hillock, the nucleus generation during the heat treatment of the ferroelectric film 55 is high, and good nucleus growth is performed. Not high, the ferroelectric film 55 can be formed. Therefore, a dielectric thin film element having improved dielectric strength, fatigue resistance, and dielectric constant can be obtained.

[0169] 3. In a dielectric thin film element having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film, The lower electrode comprises a first layer formed on the substrate and a second layer formed on the first layer and in contact with the high and ferroelectric films, and the first layer of the lower electrode is made of Pt. The second layer of the electrode is Ph, Ru, Os, I
A dielectric thin film element comprising Pt containing at least one element of r.

[Structure] The present invention corresponds to the third embodiment. In the third embodiment, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. This lower layer 52 is an insulating film, polycrystalline S
The i-layer or the semiconductor diffusion region corresponds to the lower layer 52
Pt is formed on the lower electrode 54 as a first layer 54a, and Rh, Ru, and O are formed on the Pt as a second layer 54b of the lower electrode 54.
Pt containing at least one element of s and Ir is formed, a high ferroelectric film 55 is formed thereon, and Pt is formed thereon as an upper electrode 56. .

[Operation] By using Pt containing at least one element of Rh, Ru, Os, and Ir as the second layer 54b of the lower electrode 54, the ductility of Pt is reduced, the rigidity is increased, and the crystallinity is increased. The grain size becomes smaller and the variation in crystal grain size becomes smaller. As a result, hillocks are not generated on the surface of the second layer 54b of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, and the flatness is maintained. Since the growth is performed favorably, the occurrence of defects is suppressed. Furthermore, Rh, Ru, O
An increase in the lower electrode resistance caused by using Pt containing at least one element of s and Ir can be prevented by using Pt as the first layer 54a of the lower electrode 54.

[Effect] Since there is no abnormal deposit such as hillock on the surface of the second layer 54b of the lower electrode 54, the upper electrode
Since it is possible to prevent electric field concentration that occurs when a voltage is applied between the lower electrode 56 and the lower electrode 54, it is possible to improve the withstand voltage and fatigue resistance. Furthermore, since the crystal grain size of the second layer 54b of the lower electrode 54 is small and has little variation, and there is no hillock, high nucleation during the heat treatment of the ferroelectric film 55 is uniform and good nucleation is achieved. As a result, the high ferroelectric film 55 without defects can be formed. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength, fatigue resistance, and dielectric constant. In addition, since the resistance is prevented from being increased by using Pt as the first layer 54a of the lower electrode 54, the electrode resistance of the conventional dielectric thin film element can be maintained.

4. In a dielectric thin film element having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film, The lower electrode comprises a first layer formed on the substrate and a second layer formed on the first layer and in contact with the high and ferroelectric films, and the first layer of the lower electrode is made of Pt. The second layer of the electrode is Rh, Ru, Os, I
The upper electrode is composed of Pt containing at least one element of r, and the upper electrode is composed of a first layer formed on the high ferroelectric film and a second layer formed on the first layer. A dielectric thin film element, wherein the first layer of the electrode is made of Pt containing at least one element of Rh, Ru, Os and Ir, and the second layer of the upper electrode is made of Pt.

[Structure] The present invention corresponds to the fourth embodiment. In Example 4, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. This lower layer 53 is an insulating film, polycrystalline S
The i-layer or the semiconductor diffusion region corresponds to the lower layer 53
Pt is formed on the lower electrode 54 as a first layer 54a, and Rh, Ru, and O are formed on the Pt as a second layer 54b of the lower electrode 54.
Pt containing at least one element of s and Ir is formed, and a high ferroelectric film 55 is formed thereon. Furthermore, the first layer of the upper electrode 56 on the high ferroelectric film 55.
As 56a, Pt containing at least one element of Rh, Ru, Os, and Ir is formed, and the upper electrode is formed thereon.
Pt is formed as the second layer 56b of 56.

[Operation] By using Pt containing at least one element of Rh, Ru, Os, and Ir as the second layer 54b of the lower electrode 54, the ductility of Pt is reduced, the rigidity is increased, and the crystal is formed. The grain size becomes smaller and the variation in crystal grain size becomes smaller. As a result, hillocks are not generated on the surface of the second layer 54b of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, and the flatness is maintained. Since the growth is performed favorably, the occurrence of defects is suppressed. Furthermore, by using Pt containing at least one element of Rh, Ru, Os, and Ir also in the first layer 56a of the upper electrode 56, even if heat treatment at 600 ° C. or higher is performed after the upper electrode is formed, It is possible to prevent abnormal deposits such as hillocks from occurring at the interface between the ferroelectric film 55 and the second layer 54b of the lower electrode 54 and the first layer 56a of the upper electrode 56. Further, the increase of the upper and lower electrode resistance due to the use of Pt containing at least one element of Rh, Ru, Os, and Ir is increased by Pt as the first layer 54a of the lower electrode 54 and the second layer 56a of the upper electrode 56. Can be prevented by using.

[Effects] High, ferroelectric film 55 and lower electrode 54
Since no abnormal deposits such as hillocks are present at the interface between the upper electrode 56 and the upper electrode 56, it is possible to prevent electric field concentration that occurs when a voltage is applied between the upper electrode 56 and the lower electrode 54, so that the dielectric strength and fatigue resistance can be improved. be able to. Furthermore, since the crystal grain size of the second layer 54b of the lower electrode 54 is small and the variation is small, and there is no hillock, the high ferroelectric film 55 is obtained.
Since the nuclei are uniformly generated during the heat treatment and good nucleation is performed, a high-definition ferroelectric film 55 having no defects can be formed.
Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength, fatigue resistance, and dielectric constant. Further, by preventing the resistance from increasing by using Pt as the first layer 54a of the lower electrode 54 and the second layer 56b of the upper electrode 56, it is possible to maintain the electrode resistance of the conventional high ferroelectric thin film element.

5. In a dielectric thin film element having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film, The lower electrode is composed of a first layer formed on a substrate and a second layer formed thereon and in contact with the high and ferroelectric films, wherein the first layer of the lower electrode is a conductive oxide and The second layer of the lower electrode is Rh, Ru, Os, I
A dielectric thin film element comprising a Pt material containing at least one element of r.

[Structure] The present invention corresponds to the fifth embodiment. In the fifth embodiment, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. This lower layer 53 is an insulating film, polycrystalline S
The i-layer or the semiconductor diffusion region corresponds to the lower layer 53
A conductive oxide is formed as a first layer 54a of the lower electrode 54 on the upper surface, and Rh, R as a second layer 54b of the lower electrode 54 are formed thereon.
The structure is such that Pt containing at least one element of u, Os and Ir is formed, a high ferroelectric film 55 is formed thereon, and Pt is further formed thereon as an upper electrode 56. ing.

[Operation] By using Pt containing at least one element of Rh, Ru, Os, and Ir as the second layer 54b of the lower electrode 54, the ductility of Pt is reduced, the rigidity is increased, and the crystallinity is increased. The grain size becomes smaller and the variation in crystal grain size becomes smaller. As a result, hillocks are not generated on the surface of the second layer 54b of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, and the flatness is maintained. Since the growth is performed favorably, the occurrence of defects is suppressed. Furthermore, by using a conductive oxide as the first layer 54a of the lower electrode 54, the adhesiveness between the lower electrode 54 and the lower layer 53 is improved and the lower layer 53
It is possible to prevent the diffusion of high Si etc. into the ferroelectric film 55.

[Effect] Since there is no abnormal deposit such as hillock on the surface of the second layer 54b of the lower electrode 54,
Since it is possible to prevent electric field concentration that occurs when a voltage is applied between the lower electrode 56 and the lower electrode 54, it is possible to improve the withstand voltage and fatigue resistance. Furthermore, since the crystal grain size of the second layer 54b of the lower electrode 54 is small and has little variation, and there is no hillock, high nucleation during the heat treatment of the ferroelectric film 55 is uniform and good nucleation is achieved. As a result, the high ferroelectric film 55 without defects can be formed. In addition, the adhesion between the lower electrode 54 and the lower layer 53 is good, and the Si in the ferroelectric film 55 is high.
It is possible to obtain a dielectric thin film element in which film peeling does not occur and dielectric strength, fatigue resistance, and dielectric constant are improved because the diffusion of the like can be suppressed.

6. 4. The second layer of the lower electrode and the upper electrode are composed of a Pt material containing at least one element of Rh, Ru, Os, and Ir. The dielectric thin film element described.

[Structure] The present invention corresponds to the sixth embodiment. In Example 6, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region.
A conductive oxide is formed on the 53 as the first layer 54a of the lower electrode 54, and Rh is formed thereon as the second layer 54b of the lower electrode 54.
Pt containing at least one element of Ru, Os, and Ir is formed, a high ferroelectric film 55 is formed thereon, and Rh, Ru, O as an upper electrode 56 are further formed thereon.
It has a structure in which Pt containing at least one element of s and Ir is formed.

[Operation] As the second layer 54b of the lower electrode 54, R
By using Pt containing at least one element of h, Ru, Os, and Ir, the ductility of Pt is reduced and the rigidity is increased, and the crystal grain size is reduced to reduce the variation of the crystal grain size. As a result, hillocks are not generated on the surface of the second layer 54b of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, and the flatness is maintained. Since the growth is performed favorably, the occurrence of defects is suppressed. In addition, Rh,
By using Pt containing at least one element of Ru, Os, and Ir, the second layer 54b of the high / ferroelectric film 55 lower electrode 54 can be formed even if a heat treatment at 600 ° C. or higher is performed after the upper electrode is formed. Also, it is possible to prevent abnormal deposits such as hillocks from being generated at the interface of the upper electrode 56. In addition, the lower electrode 54
By using a conductive oxide as the first layer 54a of
Adhesion between the lower electrode 54 and the lower layer 53 is improved, and diffusion of Si or the like in the lower layer 53 to the high-strength ferroelectric film 55 can be prevented.

[Effects] High, ferroelectric film 55 and lower electrode 54
Since no abnormal deposits such as hillocks exist at the interface between the second layer 54b and the upper electrode 56, it is possible to prevent electric field concentration that occurs when a voltage is applied between the upper electrode 56 and the lower electrode 54.
The withstand voltage and fatigue resistance can be improved.
Furthermore, since the crystal grain size of the second layer 54b of the lower electrode 54 is small and has little variation, and there is no hillock, it is high.
Since nuclei are uniformly generated during the heat treatment of the ferroelectric film 55 and favorable nuclei growth is performed, a high-definition ferroelectric film 55 having no defects can be formed. Further, the adhesion between the lower electrode 54 and the lower layer 53 is good, and high, since it is possible to suppress the diffusion of Si and the like into the ferroelectric film 55, no film peeling occurs, dielectric strength, fatigue resistance characteristics A dielectric thin film element having an improved dielectric constant can be obtained.

7. In a dielectric thin film element having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film, The lower electrode is a first layer formed on an insulating film, a polycrystalline Si layer or a semiconductor diffusion region, a second layer formed on the first layer, and a third layer formed on the first layer and in contact with the high and ferroelectric films. And the first layer of the lower electrode is a conductive oxide, the second layer is Pt and the third layer is Rh,
It is Pt containing at least one element of Ru, Os and Ir, and the upper electrode is composed of a first layer formed on the high ferroelectric film and a second layer formed thereon. And the first layer of the upper electrode is Rh, Ru, O
A dielectric thin film element comprising Pt containing at least one element of s and Ir, and wherein the second layer of the upper electrode is composed of Pt.

[Structure] The present invention corresponds to the seventh embodiment. In Example 7, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. This lower layer 53 is an insulating film, polycrystalline S
The i-layer or the semiconductor diffusion region corresponds to the lower layer 53
A conductive oxide is formed as the first layer 54a of the lower electrode 54, Pt is formed thereon as the second layer 54b of the lower electrode 54, and Rh, Ru as the third layer 54c is further formed thereon.
Pt containing at least one element of Os and Ir
Is formed, and a high ferroelectric film 55 is formed thereon. Furthermore, the first layer of the upper electrode 56 on the high ferroelectric film 55.
As 56a, Pt containing at least one element of Rh, Ru, Os, and Ir is formed, and the upper electrode is formed thereon.
Pt is formed as the second layer 56b of 56.

[Operation] By using Pt containing at least one element of Rh, Ru, Os, and Ir as the third layer 54c of the lower electrode 54, the ductility of Pt is reduced, the rigidity is increased, and the crystallinity is increased. The grain size becomes smaller and the variation in crystal grain size becomes smaller. As a result, hillocks are not generated on the surface of the third layer 54c of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, and the flatness is maintained. Since the growth is performed favorably, the occurrence of defects is suppressed. Furthermore, by using Pt containing at least one element of Rh, Ru, Os, and Ir also in the first layer 54a of the upper electrode 54, even if heat treatment at 600 ° C. or higher is performed after the upper electrode is formed, Ferroelectric film 55, third layer 54c of lower electrode 54 and first layer of upper electrode 56
It is possible to prevent the occurrence of abnormal deposits such as hillocks at the interface of 56a. Further, the resistance of the upper and lower electrodes 56 and the lower electrode 54 is increased by using Pt containing at least one element of Rh, Ru, Os, and Ir. This can be prevented by using Pt as the layer 56b. In addition, the first layer 54a of the lower electrode 54
By using a conductive oxide as the material, the adhesion between the lower electrode 54 and the lower layer 53 is improved, and the Si in the lower layer 53 is improved.
It is possible to prevent the diffusion to the ferroelectric film 55.

[Effect] High ferroelectric film 55 and lower electrode 54
Since no abnormal deposits such as hillocks are present at the interface between the third layer 54c and the first layer 56a of the upper electrode 56, it is possible to prevent the electric field concentration that occurs when a voltage is applied between the upper electrode 56 and the lower electrode 54. The withstand voltage and fatigue resistance can be improved. Furthermore, since the crystal grain size of the third layer 54c of the lower electrode 54 is small and has little variation, and there is no hillock, high nucleation during the heat treatment of the ferroelectric film 55 is uniform and good nucleation is achieved. As a result, the high ferroelectric film 55 without defects can be formed. Further, the adhesion between the lower electrode 54 and the lower layer 53 is good, high, since it is possible to suppress the diffusion of Si and the like into the ferroelectric film 55, the film peeling does not occur, the dielectric strength,
It is possible to obtain a high ferroelectric thin film element having improved fatigue resistance and dielectric constant. Further, the second layer 54b of the lower electrode 54
Also, by preventing Pt from being used as the second layer 56b of the upper electrode 56, it is possible to maintain the electrode resistance of the conventional dielectric thin film element.

8. In an electrode made of Pt containing at least one element of Rh, Ru, Os and Ir,
At least one element selected from the group consisting of Rh, Ru, Os, and Ir is contained in an amount of 10% by weight. To the above 7. The dielectric thin film element described.

[Structure] The present invention corresponds to Embodiments 1 to 7.

[Operation] By using Pt containing 10% of at least one of Rh, Ru, Os, and Ir as the lower electrode 54 in contact with the ferroelectric film 55, the ductility of Pt becomes small. The rigidity is increased, the crystal grain size is reduced, and the variation of the crystal grain size is reduced. As a result, even if heat treatment at 600 ° C or higher is performed, the lower electrode
No hillocks are generated on the surface of the high and ferroelectric film 55, flatness is maintained, and nuclei are grown well during the heat treatment of the high and ferroelectric film 55, so that no defect is generated. Suppressed. Higher upper electrode in contact with the ferroelectric film 55
By using Pt containing 10% of at least one element out of Rh, Ru, Os, and Ir also for 56, even if the lower electrode 54 is heat-treated at 600 ° C. or higher after the upper electrode is formed.
Also, it is possible to prevent abnormal deposits such as hillocks from being generated at the interface between the high electrode 56 and the ferroelectric film 55.

[Effects] Abnormal precipitates such as hillocks do not exist at the interfaces of the lower electrode 54 and the upper electrode 56 which are in contact with the ferroelectric film 55. Therefore, when a voltage is applied between the upper electrode 56 and the lower electrode 54, Since it is possible to prevent the generated electric field concentration, it is possible to improve the dielectric strength and fatigue resistance. Furthermore, since the crystal grain size on the surface of the lower electrode in contact with the high ferroelectric film 55 is small and the variation is small and there is no hillock, the generation of nuclei during the heat treatment of the high ferroelectric film 55 is uniform and good. Since the nuclei are grown, a high-definition ferroelectric film 55 having no defects can be formed. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength, fatigue resistance, and dielectric constant.

9. A lower electrode formed on the substrate; a Bi layered ferroelectric film formed on the lower electrode;
In a dielectric thin film element having an upper electrode formed on an i-layered ferroelectric film, the lower electrode is Bi or B
A dielectric thin film element comprising Pt containing i and Sr.

[Structure] The present invention corresponds to the eighth embodiment. In the eighth embodiment, the lower layer 53 of the high ferroelectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region. On the lower layer 53, Bi or Pt containing Bi and Sr is formed as a lower electrode 54, and a Bi layered ferroelectric substance is formed thereon. A film (high, ferroelectric film) 55 is formed, and Pt as an upper electrode 56 is further formed thereon.

[Operation] As the lower electrode 54, Bi or Pt containing Bi and Sr is used, and the Bi layered ferroelectric film is used.
By alloying Bi ₂ Pt, BiPt, Pt ₃ Sr ₇ etc. before formation of 55, even if a Bi layered ferroelectric film 55 containing Sr is subjected to a heat treatment at 600 ° C. or higher during formation, It is possible to prevent diffusion of Bi or Sr, which is an element of the Bi layered ferroelectric film 55, into the lower electrode 54.

[Effect] Since the elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54, the Bi layered ferroelectric film is formed.
The composition of 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength and dielectric constant.

10. 8. The lower electrode and the upper electrode are composed of Bi or Pt containing Bi and Sr. The dielectric thin film element described.

[Structure] This invention corresponds to the ninth embodiment. In Example 9, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. This lower layer 53 is an insulating film, polycrystalline S
The i-layer or the semiconductor diffusion region corresponds to the lower layer 53
Pt containing Bi or Bi and Sr is formed thereon as a lower electrode 54, a Bi layered ferroelectric film 55 is formed thereon, and Pt containing Bi or Bi and Sr is formed as an upper electrode 56 thereon. The structure is formed.

[Operation] By using Pt containing Bi or Bi and Sr as the lower electrode 54 and the upper electrode 56, by alloying Bi ₂ Pt, BiPt, Pt ₃ Sr ₇ etc. during electrode formation , B containing Sr, for example
Even if a heat treatment of 600 ° C. or more is performed during the formation of the i-layered ferroelectric film 55 or after the formation of the upper electrode, the lower electrode 54
Further, it is possible to prevent diffusion of Bi or Sr, which is an element of the Bi layered ferroelectric film 55, into the upper electrode 56.

[Effect] The elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54 and the upper electrode 56, and
The composition of the layered ferroelectric film 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength and dielectric constant.

11. A dielectric thin film element having a lower electrode formed on a substrate, a Bi layered ferroelectric film formed on the lower electrode, and an upper electrode formed on the Bi layered ferroelectric film, wherein: The lower electrode is composed of a first layer formed on a substrate and a second layer formed thereon and in contact with the Bi layered ferroelectric film, wherein the first layer of the lower electrode is Pt and the lower electrode is The second layer is Bi or B
A dielectric thin film element comprising Pt containing i and Sr.

[Structure] The present invention corresponds to the tenth embodiment. In the tenth embodiment, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region.
Pt is formed on the 53 as the first layer 54a of the lower electrode 54,
On top of that, Bi or B is used as the second layer 54b of the lower electrode 54.
The structure is such that Pt containing i and Sr is formed, a Bi layered ferroelectric film 55 is formed thereon, and Pt is further formed thereon as an upper electrode 56.

[Operation] Bi or Pt containing Bi and Sr is used as the second layer 54b of the lower electrode 54, and Bi ₂ Pt, BiPt, Pt ₃ S is formed before forming the Bi layered ferroelectric film.
By alloying r ₇ etc., the Bi layered ferroelectric film 55 for the lower electrode 54 can be formed even if a heat treatment of 600 ° C. or more is performed when the Bi layered ferroelectric film 55 containing Sr is formed. It is possible to prevent the diffusion of Bi or Sr, which is the element. Further, an increase in the lower electrode resistance due to the use of Pt containing Bi or Bi and Sr can be prevented by using Pt as the first layer 54a of the lower electrode 54.

[Effect] The elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54, so that the Bi layered ferroelectric film is formed.
The composition of 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength and dielectric constant. Also, the lower electrode 54
Since Pt is used as the first layer 54a to prevent the resistance from increasing, the electrode resistance of the conventional dielectric thin film element can be maintained.

12. A dielectric thin film element having a lower electrode formed on a substrate, a Bi layered ferroelectric film formed on the lower electrode, and an upper electrode formed on the Bi layered ferroelectric film, wherein: The lower electrode is composed of a first layer formed on a substrate and a second layer formed thereon and in contact with the Bi layered ferroelectric film, wherein the first layer of the lower electrode is Pt and the lower electrode is The second layer is Bi or B
Pt containing i and Sr, wherein the upper electrode is composed of a first layer formed on the Bi layered ferroelectric film and a second layer formed on the first layer. A dielectric thin film element, wherein one layer is Pt containing Bi or Bi and Sr and the second layer of the upper electrode is composed of Pt.

[Structure] The present invention corresponds to the eleventh embodiment. In Example 11, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region.
Pt is formed on the 53 as the first layer 54a of the lower electrode 54,
On top of that, Bi or B is used as the second layer 54b of the lower electrode 54.
Pt containing i and Sr is formed, and a Bi layered ferroelectric film 55 is formed thereon. Further, Pt containing Bi or Bi and Sr is formed as the first layer 56a of the upper electrode 56 on the Bi layered ferroelectric film 55, and Pt is formed thereon as the second layer 56b of the upper electrode 56. There is.

[Operation] Bi or Pt containing Bi and Sr is used as the second layer 54b of the lower electrode 54 and the first layer 54a of the upper electrode 54, and Bi ₂ Pt,
By alloying BiPt, Pt ₃ Sr _7, etc., the lower electrode can be formed even if a heat treatment at 600 ° C. or more is performed at the time of forming the Bi layered ferroelectric film 55 containing Sr or after forming the upper electrode. It is possible to prevent diffusion of Bi or Sr, which is an element of the Bi layered ferroelectric film 55, into the 54 and the upper electrode 56. Furthermore, the increase of the resistance of the upper electrode 56 and the lower electrode 54 by using Pt containing Bi or Bi and Sr can be improved by using Pt as the first layer 54a of the lower electrode 54 and the second layer 56b of the upper electrode 56. It can be prevented.

[Effect] The elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54 and the upper electrode 56, and
The composition of the layered ferroelectric film 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength and dielectric constant. In addition, the first layer 54 a of the lower electrode 54 and the second layer 56 of the upper electrode 56.
By preventing the resistance from increasing by using Pt as b, the electrode resistance of the conventional dielectric thin film element can be maintained.

13. A dielectric thin film element having a lower electrode formed on a substrate, a Bi layered ferroelectric film formed on the lower electrode, and an upper electrode formed on the Bi layered ferroelectric film, wherein: The lower electrode is composed of a first layer formed on a substrate and a second layer formed thereon and in contact with the Bi layered ferroelectric film, wherein the first layer of the lower electrode is a conductive oxide and 2. A dielectric thin film element, wherein the second layer of the lower electrode is composed of Bi or a Pt material containing Bi and Sr.

[Structure] The present invention corresponds to the twelfth embodiment. In Example 12, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region. A conductive oxide is formed on the lower layer 53 as the first layer 54a of the lower electrode 54, and the conductive oxide of the lower electrode 54 is formed thereon. Bi as the two layers 54b
Alternatively, the structure is such that Pt containing Bi and Sr is formed, the Bi layered ferroelectric film 55 is formed thereon, and Pt is further formed thereon as the upper electrode 56.

[Operation] Bi or Pt containing Bi and Sr is used as the second layer 54b of the lower electrode 54, and Bi ₂ Pt, BiPt, Pt ₃ S is formed before the formation of the Bi layered ferroelectric film.
By alloying r ₇ etc., the Bi layered ferroelectric film 55 for the lower electrode 54 can be formed even if a heat treatment of 600 ° C. or more is performed when the Bi layered ferroelectric film 55 containing Sr is formed. It is possible to prevent the diffusion of Bi or Sr, which is the element. Furthermore, by using a conductive oxide as the first layer 54a of the lower electrode 54, the adhesion between the lower electrode 54 and the lower layer 53 is improved, and the Bi layered ferroelectric film 55 such as Si in the lower layer 53 is formed. It is possible to prevent the diffusion inside.

[Effect] The elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54, so that the Bi layered ferroelectric film is formed.
The composition of 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. In addition, since the adhesion between the lower electrode 54 and the lower layer 53 is good and the diffusion of Si or the like into the Bi layered ferroelectric film 55 can be suppressed, film peeling does not occur and the dielectric strength and dielectric constant are improved. The dielectric thin film element can be obtained.

14. 13. The second layer of the lower electrode and the upper electrode are made of Bi or a Pt material containing Bi and Sr. The dielectric thin film element described.

[Structure] The present invention corresponds to the thirteenth embodiment. In Example 13, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. This lower layer 53 is an insulating film, polycrystalline S
The i-layer or the semiconductor diffusion region corresponds to the lower layer 53
A conductive oxide is formed as the first layer 54a of the lower electrode 54, and Bi or Pt containing Bi and Sr is formed as the second layer 54b of the lower electrode 54 on the conductive oxide.
An i-layered ferroelectric film 55 is formed, and Bi or Pt containing Bi and Sr is formed as an upper electrode 56 on the i-layered ferroelectric film 55.

[Operation] As the second layer 54b of the lower electrode 54 and the upper electrode 56, Pt containing Bi or Bi and Sr
Is used to form Bi ₂ Pt, BiPt, P
By alloying with t ₃ Sr ₇ or the like, for example, even when the Bi layered ferroelectric film 55 containing Sr is formed or after heat treatment at 600 ° C. or more is performed after the formation of the upper electrode, the upper electrode 56, Bi layered ferroelectric film 55 on the lower electrode 54
It is possible to prevent the diffusion of Bi or Sr, which is the element. Furthermore, by using a conductive oxide as the first layer 54a of the lower electrode 54, the adhesion between the lower electrode 54 and the lower layer 53 is improved, and the Bi layered ferroelectric film such as Si in the lower layer 53 is formed.
It is possible to prevent the diffusion to 55.

[Effect] Since the elements in the Bi layered ferroelectric film 55 do not diffuse to the upper electrode 56 and the lower electrode 54, the composition of the Bi layered ferroelectric film 55 does not change, and a good Bi layered ferroelectric film is obtained. The body membrane 55 can be formed. Also, the lower electrode 54 and the lower layer
Adhesiveness to 53 is good and S in Bi layered ferroelectric film 55
Since the diffusion of i etc. can be suppressed, film peeling does not occur,
It is possible to obtain a dielectric thin film element having improved dielectric strength and dielectric constant.

15. A lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, the high electrode,
In a dielectric thin film element having an upper electrode formed on a ferroelectric film, the lower electrode is formed on a first layer formed on the substrate, a second layer formed thereon and a second layer formed thereon. And a third layer in contact with the ferroelectric film,
The first layer of the lower electrode is a conductive oxide, the second layer is Pt and the third layer is Pt containing Bi or Bi and Sr, and the upper electrode is on the high ferroelectric film. It is composed of a first layer formed and a second layer formed thereon, and the first layer of the upper electrode is Bi or Bi and Sr.
2. A dielectric thin film element comprising Pt and containing Pt as a second layer of the upper electrode.

[Structure] The present invention corresponds to the fourteenth embodiment. In Example 14, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region.
Conductive oxidation is formed as the first layer 54a of the lower electrode 54 on 53, Pt is formed thereon as the second layer 54b of the lower electrode 54, and Bi or Bi and Sr as the third layer 54c is further formed thereon. Is formed, and a Bi layered ferroelectric film 55 is formed thereon. Further, Pt containing Bi or Bi and Sr is formed as the first layer 56a of the upper electrode 56 on the Bi layered ferroelectric film 55, and Pt is formed thereon as the second layer 56b of the upper electrode 56. There is.

[Operation] Bi or Pt containing Bi and Sr is used as the third layer 56c of the lower electrode 56 and the first layer 56a of the upper electrode 56, and Bi ₂ Pt,
By alloying BiPt, Pt ₃ Sr _7, etc., the lower electrode can be formed even if a heat treatment at 600 ° C. or more is performed at the time of forming the Bi layered ferroelectric film 55 containing Sr or after forming the upper electrode. It is possible to prevent diffusion of Bi or Sr, which is an element of the Bi layered ferroelectric film 55, into the 54 and the upper electrode 56. Furthermore, the increase of the resistance of the upper electrode 56 and the lower electrode 54 by using Pt containing Bi or Bi and Sr is improved by using Pt as the second layer 54b of the lower electrode 54 and the second layer 56b of the upper electrode 56. It can be prevented. Further, by using a conductive oxide as the first layer 54a of the lower electrode 54, the adhesion between the lower electrode 54 and the lower layer 53 is improved, and the Bi layered ferroelectric film 55 such as Si in the lower layer 53 is formed.
Can be prevented from spreading.

[Effect] The element in the Bi layered ferroelectric film 55 does not diffuse to the lower electrode 54 and the upper electrode 56, and
The composition of the layered ferroelectric film 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. In addition, since the adhesion between the lower electrode 54 and the lower layer 53 is good and the diffusion of Si or the like into the Bi layered ferroelectric film 55 can be suppressed, film peeling does not occur and the dielectric strength and dielectric constant are An improved dielectric thin film element can be obtained. Furthermore, by preventing Pt from being used as the second layer 54b of the lower electrode 5 and the second layer 56b of the upper electrode 56, it is possible to maintain the electrode resistance of the conventional dielectric thin film element.

16. 9. An electrode made of a Pt material containing Bi, wherein the atomic ratio is Bi: Pt = 2: 1 or 1: 1. To the above 15. The dielectric thin film element described.

[Structure] The present invention corresponds to Embodiments 8 to 14.

[Operation] Pt having an atomic ratio of Bi: Pt = 2: 1 or 1: 1 is used as the lower electrode 54 in contact with the Bi layered ferroelectric film 55, and B is formed before the formation of the Bi layered ferroelectric film.
By alloying i ₂ Pt, BiPt, or the like, even if a heat treatment at 600 ° C. or higher is performed at the time of forming the Bi layered ferroelectric film 55, the Bi layered ferroelectric film 55 is formed on the lower electrode 54. It is possible to prevent the diffusion of the element Bi. further,
As the upper electrode 56 in contact with the Bi layered ferroelectric film 55, Pt having an atomic ratio of Bi: Pt = 2: 1 or 1: 1 is used,
By alloying Bi ₂ Pt, BiPt, or the like at the time of forming the electrode, it is possible to prevent the diffusion of Bi into the upper electrode 56 even if a heat treatment at 600 ° C. or higher is performed after the upper electrode is formed.

[Effect] Since the elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54 and the upper electrode 56, Bi
The composition of the layered ferroelectric film 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength, fatigue resistance, and dielectric constant.

17. A dielectric thin film element having a lower electrode formed on a substrate, a Bi layered ferroelectric film formed on the lower electrode, and an upper electrode formed on the Bi layered ferroelectric film, wherein: The lower electrode is Rh, Ru,
A dielectric thin film element comprising at least one element of Os and Ir and Pt containing Bi or Bi and Sr.

[Structure] The present invention corresponds to the fifteenth embodiment. In the fifteenth embodiment, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region.
A Pt containing at least one element of Ru, Rh, Os, and Ir or Bi or Bi and Sr is formed as a lower electrode 54 on the 53, and a Bi layered ferroelectric film 55 is formed thereon.
Is formed, and Pt is further formed thereon as the upper electrode 56.

[Operation] R in Pt as the lower electrode 54
By containing at least one element of u, Rh, Os, and Ir, the ductility of Pt is reduced and the rigidity is increased, and the crystal grain size is reduced to reduce the variation of the crystal grain size. As a result, hillocks are not generated on the surface of the lower electrode 103 even if the heat treatment is performed at 600 ° C. or more, the flatness is maintained, and the nucleus growth during the heat treatment of the Bi layered ferroelectric film 55 is performed well. Therefore, the occurrence of defects is suppressed. Further, Bi or Bi and S are added to the lower electrode 54.
By using Pt containing r and alloying Bi ₂ Pt, BiPt, Pt ₃ Sr ₇ etc. before forming the Bi layered ferroelectric film, for example, the Bi layered ferroelectric film 55 containing Sr is formed. Even when heat treatment is performed at 600 ° C. or higher during formation, diffusion of Bi or Sr, which is an element of the Bi layered ferroelectric film 55, into the lower electrode 54 can be prevented.

[Effect] Since no abnormal deposits such as hillocks are present on the surface of the lower electrode 54, the upper electrode 56, the lower electrode
Since it is possible to prevent the electric field concentration that occurs when a voltage is applied between 54, it is possible to improve the dielectric strength and fatigue resistance. In addition, since the crystal grain size of the lower electrode 54 is small and the variation is small, and there is no hillock, nuclei are uniformly generated during heat treatment of the Bi layered ferroelectric film 55 and good nucleation is performed, so that there is no defect. The Bi layered ferroelectric film 55 can be formed. Furthermore, since the elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54, the composition of the Bi layered ferroelectric film 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. Become. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength and dielectric constant.

18. The lower electrode and the upper electrode are Rh,
At least one element of Ru, Os, and Ir, and B
17. Pt containing i or Bi and Sr. The dielectric thin film element described.

[Structure] The present invention corresponds to the sixteenth embodiment. In Example 16, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region.
A Pt containing at least one element of Ru, Rh, Os, and Ir and Bi or Bi and Sr is formed as a lower electrode 54 on 53, and a Bi layered ferroelectric film is formed thereon.
55 is formed, and Ru, Rh, and
It has a structure in which Pt containing at least one element of Os and Ir and Bi or Bi and Sr is formed.

[Function] R in Pt as the lower electrode 54
By containing at least one element of u, Rh, Os, and Ir, the ductility of Pt is reduced and the rigidity is increased, and the crystal grain size is reduced to reduce the variation of the crystal grain size. As a result, hillocks are not generated on the surface of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, the flatness is maintained, and the nucleus growth during the heat treatment of the Bi layered ferroelectric film 55 is performed well. Therefore, the occurrence of defects is suppressed. Further, by using Pt containing at least one element of Rh, Ru, Os, and Ir also for the upper electrode 56, even if a heat treatment at 600 ° C. or higher is performed after the formation of the upper electrode, the Bi layered ferroelectric film is formed. 55, lower electrode 54 and upper electrode 56
It is possible to prevent abnormal deposits such as hillocks from being generated at the interface of. Furthermore, B is used as the lower electrode 54 and the upper electrode 56.
By using Pt containing i or Bi and Sr and alloying Bi ₂ Pt, BiPt, Pt ₃ Sr ₇ etc. at the time of forming the electrode, for example, a Bi layered ferroelectric film 55 containing Sr is formed. Even when a heat treatment of 600 ° C. or higher is performed at any time or after the formation of the upper electrode 56, the lower electrode 10
It is possible to prevent diffusion of Bi or Sr, which is an element of the Bi layered ferroelectric film 55, into the 3 and the upper electrode 56.

[Effects] Abnormal deposits such as hillocks do not exist at the interface between the Bi layered ferroelectric film 55 and the lower electrode 54 and the upper electrode 56, so that a voltage is generated between the upper electrode 56 and the lower electrode 54 Since it is possible to prevent the electric field concentration from occurring, it is possible to improve the dielectric strength and fatigue resistance. In addition, since the crystal grain size of the lower electrode 54 is small and the variation is small, and there is no hillock, nuclei are uniformly generated during heat treatment of the Bi layered ferroelectric film 55 and good nucleation is performed, so that there is no defect. The Bi layered ferroelectric film 55 can be formed. Furthermore, since the elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54 and the upper electrode 56, the Bi layered ferroelectric film 55 is formed.
The composition of 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. Therefore, it is possible to obtain a dielectric thin film element having improved dielectric strength and dielectric constant.

19. A ferroelectric thin film element having a lower electrode formed on a substrate, a Bi layered ferroelectric film formed on the lower electrode, and an upper electrode formed on the Bi layered ferroelectric film, The lower electrode is composed of a first layer formed on the substrate and a second layer formed on the first layer and in contact with the Bi layered ferroelectric film, and the first layer of the lower electrode is Pt and the lower layer. The second layer of the electrode is Rh, R
at least one element selected from u, Os, and Ir, and Bi
Alternatively, the dielectric thin film element is composed of Pt containing Bi and Sr.

[Structure] The present invention corresponds to the seventeenth embodiment. In Example 17, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region. Pt is formed as the first layer 54a of the lower electrode 54 on the lower layer 53, and the second layer 54b of the lower electrode 54 is formed thereon. As Ru, R
at least one element of h, Os, and Ir and Bi
Alternatively, the structure is such that Pt containing Bi and Sr is formed, the Bi layered ferroelectric film 55 is formed thereon, and Pt is further formed thereon as the upper electrode 56.

[Function] Since Pt contains at least one element selected from Ru, Rh, Os, and Ir as the second layer 54b of the lower electrode 54, ductility of Pt is reduced and rigidity is increased. In addition, the crystal grain size becomes small and the variation in the crystal grain size becomes small. As a result, hillocks are not generated on the surface of the second layer 54b of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, the flatness is maintained, and the nucleus growth of the Bi layered ferroelectric film 55 during the heat treatment is performed. Is carried out satisfactorily, so that the occurrence of defects is suppressed. Also, the second layer of the lower electrode 54
Bi or Pt containing Bi and Sr is used as 54b, and Bi ₂ Pt, BiP is formed before forming the Bi layered ferroelectric film.
By alloying t, Pt ₃ Sr _7, etc.,
For example, when the Bi layered ferroelectric film 55 containing Sr is formed by heat treatment at 600 ° C. or higher, the B
It is possible to prevent diffusion of Bi or Sr, which is an element of the i-layered ferroelectric film 55. Furthermore, at least one element of Ru, Rh, Os, and Ir and Bi or Bi and S
An increase in the lower electrode resistance due to the use of Pt containing r can be prevented by using Pt as the first layer 54a of the lower electrode 54.

[Effect] Since there is no abnormal deposit such as hillock on the surface of the second layer 54b of the lower electrode 54,
Since it is possible to prevent electric field concentration that occurs when a voltage is applied between the lower electrode 54 and the lower electrode 54, it is possible to improve the dielectric strength voltage and fatigue resistance. Further, since the crystal grain size of the second layer 54b of the lower electrode 54 is small and has little variation, and there is no hillock, nucleation is uniform during heat treatment of the Bi layered ferroelectric film 55, and good nucleation is performed. Therefore, the defect-free Bi layered ferroelectric film 55 can be formed. Furthermore, since the elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode,
The composition of the Bi layered ferroelectric film 55 does not change and good Bi
The layered ferroelectric film 55 can be formed. Therefore, it is possible to obtain a high-strength, ferroelectric thin film element having improved dielectric strength and dielectric constant. In addition, since the resistance is prevented from being increased by using Pt as the first layer 54a of the lower electrode 54, the electrode resistance of the conventional dielectric thin film element can be maintained.

20. A dielectric element having a lower electrode formed on a substrate, a Bi layered ferroelectric film formed on the lower electrode, and an upper electrode formed on the Bi layered ferroelectric film, wherein The electrode is composed of a first layer formed on the substrate and a second layer formed thereon and in contact with the Bi layered ferroelectric film, wherein the first layer of the lower electrode is Pt and the first layer of the lower electrode is The second layer is Rh, Ru, O
At least one element of s and Ir and Pt containing Bi or Bi and Sr, and the upper electrode is formed on the first layer formed on the Bi layered ferroelectric film and the first layer. A second layer, and the first layer of the upper electrode has P containing at least one element selected from Rh, Ru, Os, and Ir, and Bi or Bi and Sr.
A dielectric thin film element, wherein the second layer of the upper electrode is made of Pt.

[Structure] The present invention corresponds to the eighteenth embodiment. In Example 18, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region. Pt is formed as the first layer 54a of the lower electrode 54 on the lower layer 53, and the second layer 54b of the lower electrode 54 is formed thereon. As Ru, R
at least one element of h, Os, and Ir and Bi
Alternatively, Pt containing Bi and Sr is formed, and the Bi layered ferroelectric film 55 is formed thereon. Further, B
On the i-layered ferroelectric film 55, Pt containing at least one element of Ru, Rh, Os, and Ir and Bi or Bi and Sr is formed as the first layer 56a of the upper electrode 56, and the upper electrode is formed thereon. Pt is formed as the second layer 56b of 56.

[Function] Since Pt contains at least one element selected from Ru, Rh, Os, and Ir as the second layer 54b of the lower electrode 54, the ductility of Pt decreases and the rigidity increases, In addition, the crystal grain size becomes small and the variation in the crystal grain size becomes small. As a result, hillocks are not generated on the surface of the second layer 54b of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, the flatness is maintained, and the nucleus growth of the Bi layered ferroelectric film 55 during the heat treatment is performed. Is carried out satisfactorily, so that the occurrence of defects is suppressed. Also, the first layer of the upper electrode 56
By using Pt containing at least one element of Rh, Ru, Os, and Ir also for 56a, even if a heat treatment at 600 ° C. or higher is performed after the formation of the upper electrode, the Bi layered ferroelectric film 55 and the lower electrode are formed. It is possible to prevent abnormal deposits such as hillocks from being generated at the interface between the second layer 54b of 54 and the first layer 56a of the upper electrode 56. Further, Pt containing Bi or Bi and Sr is used as the second layer 54b of the lower electrode 54 and the first layer 56a of the upper electrode 56, and Bi ₂ Pt, B
By alloying iPt, Pt ₃ Sr _7, etc., the lower electrode can be formed even if a heat treatment at 600 ° C. or more is performed when the Bi layered ferroelectric film 55 containing Sr is formed or after the upper electrode is formed. It is possible to prevent diffusion of Bi or Sr, which is an element of the Bi layered ferroelectric film 55, into the 54 and the upper electrode 56. Furthermore, an increase in upper and lower electrode resistance due to the use of Pt containing at least one element of Ru, Rh, Os, and Ir and Bi or Bi and Sr,
This can be prevented by using Pt as the first layer 54a of the lower electrode 54 and the second layer 56b of the upper electrode 56.

[Effects] Abnormal precipitates such as hillocks do not exist at the interfaces of the Bi layered ferroelectric film 55, the second layer 54b of the lower electrode 54, and the first layer 56a of the upper electrode 56.
6. Since the electric field concentration that occurs when a voltage is applied between the lower electrodes 54 can be prevented, the dielectric strength and fatigue resistance can be improved. Further, since the crystal grain size of the second layer 54b of the lower electrode 54 is small and has little variation, and there is no hillock, nucleation is uniform during heat treatment of the Bi layered ferroelectric film 55, and good nucleation is performed. Therefore, the defect-free Bi layered ferroelectric film 55 can be formed. Furthermore, since the elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54 and the upper electrode 56, the composition of the Bi layered ferroelectric film 55 does not change, and a good Bi layered ferroelectric film 55 is formed. Can be formed.
Therefore, it is possible to obtain a high-strength, ferroelectric thin film element having improved dielectric strength and dielectric constant. Furthermore, by preventing Pt from being used as the first layer 54a of the lower electrode 54 and the second layer 56b of the upper electrode 56, it is possible to maintain the electrode resistance of the conventional dielectric thin film element.

21. A dielectric element having a lower electrode formed on a substrate, a Bi layered ferroelectric film formed on the lower electrode, and an upper electrode formed on the Bi layered ferroelectric film, wherein The electrode is composed of a first layer formed on the substrate and a second layer formed on the first layer and in contact with the Bi layered ferroelectric film, and the first layer of the lower electrode is a conductive oxide and The second layer of the lower electrode is Rh,
A dielectric thin film element comprising a Pt material containing at least one element selected from Ru, Os, and Ir, and Bi or Bi and Sr.

[Structure] The present invention corresponds to the nineteenth embodiment. In Example 19, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region, and a conductive oxide is formed as the first layer 54a of the lower electrode 54 on the lower layer 53, and a conductive oxide of the lower electrode 54 is formed thereon. R as two layers 54b
Pt containing at least one element of u, Rh, Os and Ir and Bi or Bi and Sr is formed,
A Bi layered ferroelectric film 55 is formed on top of this, and Pt is formed thereon as an upper electrode 56.

[Function] Since Pt contains at least one element selected from Ru, Rh, Os, and Ir as the second layer 54b of the lower electrode 54, ductility of Pt is reduced and rigidity is increased. In addition, the crystal grain size becomes small and the variation in the crystal grain size becomes small. As a result, hillocks are not generated on the surface of the second layer 54b of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, the flatness is maintained, and the nucleus growth of the Bi layered ferroelectric film 55 during the heat treatment is performed. Is carried out satisfactorily, so that the occurrence of defects is suppressed. Also, the second layer of the lower electrode 54
Bi or Pt containing Bi and Sr is used as 54b, and Bi ₂ Pt, BiP is formed before forming the Bi layered ferroelectric film 55.
By alloying t, Pt ₃ Sr _7, etc.,
For example, when the Bi layered ferroelectric film 55 containing Sr is formed by heat treatment at 600 ° C. or higher, the B
It is possible to prevent diffusion of Bi or Sr, which is an element of the i-layered ferroelectric film 55. Furthermore, by using a conductive oxide as the first layer 54a of the lower electrode 54,
Adhesion with 53 is improved, and diffusion of Si or the like in the lower layer 53 to the Bi layered ferroelectric film 55 can be prevented.

[Effect] Since no abnormal deposits such as hillocks are present on the surface of the second layer 54b2 of the lower electrode 54, it is possible to prevent the electric field concentration generated when a voltage is applied between the upper and lower electrodes, so that the dielectric strength and fatigue resistance are improved. The characteristics can be improved. In addition, since the crystal grain size of the second layer 54b of the lower electrode 54 is small and has little variation, and there is no hillock, B
Since nuclei are uniformly generated during the heat treatment of the i-layered ferroelectric film 55 and good nucleation is performed, the defect-free Bi-layered ferroelectric film 55 can be formed. Further, since the elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54, the composition of the Bi layered ferroelectric film 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. . Furthermore, since the adhesion between the lower electrode 54 and the lower layer 53 is good and the diffusion of Si or the like into the Bi layered ferroelectric film 55 can be suppressed, film peeling does not occur and the dielectric strength and dielectric constant are An improved dielectric thin film element can be obtained.

22. 21. The second layer of the lower electrode and the upper electrode are composed of at least one element of Rh, Ru, Os, and Ir, and Pt material containing Bi or Bi and Sr. The dielectric thin film element described.

[Structure] The present invention corresponds to the twentieth embodiment. In Example 20, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region, and a conductive oxide is formed as the first layer 54a of the lower electrode 54 on the lower layer 53, and a conductive oxide of the lower electrode 54 is formed thereon. R as two layers 54b
Pt containing at least one element of u, Rh, Os and Ir and Bi or Bi and Sr is formed,
A Bi layered ferroelectric film 55 is formed thereon, and further, an upper electrode 56 is formed with at least one element of Ru, Rh, Os and Ir and Pt containing Bi or Bi and Sr. It is structured.

[Operation] Since Pt contains at least one element selected from Ru, Rh, Os, and Ir as the second layer 54b of the lower electrode 54, ductility of Pt is decreased and rigidity is increased. In addition, the crystal grain size becomes small and the variation in the crystal grain size becomes small. As a result, hillocks are not generated on the surface of the second layer 54b of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or higher, the flatness is maintained, and the nucleus growth of the Bi layered ferroelectric film 55 during the heat treatment is performed. Is carried out satisfactorily, so that the occurrence of defects is suppressed. Also, the upper electrode 56 is R
By using Pt containing at least one element of h, Ru, Os and Ir, 600 ° C. after forming the upper electrode
Even if the above heat treatment is performed, it is possible to prevent abnormal deposits such as hillocks from being generated at the interface between the ferroelectric film 56, the second layer 54b of the lower electrode 54 and the upper electrode 56. The second layer 54b of the lower electrode 54 and Bi or Bi and S are used as the upper electrode 56.
Using Pt containing r, Bi ₂ P
By alloying t, BiPt, Pt ₃ Sr _7, etc., even if a heat treatment at 600 ° C. or more is performed when the Bi layered ferroelectric film 55 containing Sr is formed or after the upper electrode 56 is formed. , Bi to upper electrode 56, lower electrode 54
It is possible to prevent diffusion of Bi or Sr which is an element of the layered ferroelectric film 55. Further, by using a conductive oxide as the first layer 54a of the lower electrode 54, the lower electrode 54 and the lower layer 54
Adhesiveness with B becomes good and B such as Si in the lower layer 53
It is possible to prevent diffusion into the i-layered ferroelectric film 55.

[Effects] Abnormal precipitates such as hillocks do not exist at the interfaces between the Bi layered ferroelectric film 55, the second layer 54b of the lower electrode 54, and the upper electrode 56. Since it is possible to prevent electric field concentration that occurs when a voltage is applied, it is possible to improve the dielectric strength voltage and fatigue resistance. In addition, since the crystal grain size of the second layer 54b of the lower electrode 54 is small and has little variation, and there is no hillock, nucleation during the heat treatment of the Bi layered ferroelectric film 104 is uniform and good nucleation is performed. So no defect B
The i-layered ferroelectric film 55 can be formed. Furthermore, since the elements in the Bi layered ferroelectric film 55 do not diffuse to the upper electrode 56 and the lower electrode 54, the composition change of the Bi layered ferroelectric film 55 does not occur, and a good Bi layered ferroelectric film 55 is formed. Can be formed. Furthermore, the adhesion between the lower electrode 54 and the lower layer 53 is good, and Bi
Since diffusion of Si or the like into the layered ferroelectric film 55 can be suppressed, film peeling does not occur, and a dielectric thin film element with improved dielectric strength and dielectric constant can be obtained.

23. A lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, the high electrode,
In a dielectric thin film element having an upper electrode formed on a ferroelectric film, the lower electrode includes a first layer formed on the substrate, a second layer formed on the first layer, and the second layer formed on the first layer. And a third layer in contact with the ferroelectric film, the first layer of the lower electrode is a conductive oxide, the second layer is Pt, and the third layer is at least Rh, Ru, Os, or Ir. P containing one element and Bi or Bi and Sr
t, and the upper electrode is composed of a first layer formed on the high ferroelectric film and a second layer formed thereon, and the first layer of the upper electrode is Rh, Ru. , Os,
A dielectric thin film element comprising Pt containing at least one element of Ir and Bi or Bi and Sr, and the second layer of the upper electrode) made of Pt.

[Structure] The present invention corresponds to the twenty-first embodiment. In Example 21, the lower layer 53 of the dielectric thin film element is formed on the substrate 52. The lower layer 53 corresponds to an insulating film, a polycrystalline Si layer, or a semiconductor diffusion region. A conductive oxide is formed on the lower layer 53 as the first layer 54a of the lower electrode 54, and the conductive oxide of the lower electrode 54 is formed thereon. Pt as the two layers 54b
Is formed, and on top of that, Ru and R are formed as a third layer 54c.
at least one element of h, Os, and Ir and Bi
Alternatively, Pt containing Bi and Sr is formed, and the Bi layered ferroelectric film 55 is formed thereon. Further, B
On the i-layered ferroelectric film 55, Pt containing at least one element of Ru, Rh, Os, and Ir and Bi or Bi and Sr is formed as the first layer 56a of the upper electrode 56, and the upper electrode is formed thereon. Pt is formed as the second layer 56b of 56.

[Operation] Since at least one element selected from Ru, Rh, Os, and Ir is contained in Pt as the third layer 54c of the lower electrode 54, ductility of Pt is reduced and rigidity is increased. In addition, the crystal grain size becomes small and the variation in the crystal grain size becomes small. As a result, hillocks are not generated on the surface of the third layer 54c of the lower electrode 54 even if the heat treatment is performed at 600 ° C. or more, the flatness is maintained, and the nucleus growth of the Bi layered ferroelectric film 55 during the heat treatment is performed. Is carried out satisfactorily, so that the occurrence of defects is suppressed. Also, the first layer of the upper electrode 56
By using Pt containing at least one element of Rh, Ru, Os, and Ir also for 56c, even if a heat treatment at 600 ° C. or higher is performed after the formation of the upper electrode, the Bi layered ferroelectric film 55 and the lower electrode are formed. It is possible to prevent the occurrence of abnormal deposits such as hillocks at the interface between the third layer 54c of 54 and the first layer 56a of the upper electrode 56. Further, Bi or Pt containing Bi and Sr is used as the third layer 54c of the lower electrode 54 and the first layer 56a of the upper electrode 56, and Bi ₂ Pt, Bi
By alloying Pt, Pt ₃ Sr ₇ or the like in advance, even if a heat treatment at 600 ° C. or higher is performed at the time of forming the Bi layered ferroelectric film 55 containing Sr or after forming the upper electrode, the lower electrode It is possible to prevent diffusion of Bi or Sr, which is an element of the Bi layered ferroelectric film 55, into the 54 and the upper electrode 56. Further, by using Pt containing at least one element of Rh, Ru, Os, and Ir and Bi or Bi and Sr, the resistance of the upper electrode 56 and the lower electrode 54 can be increased by the second layer 54b of the lower electrode 54 and This can be prevented by using Pt as the second layer 56b of the upper electrode 56. Further, by using a conductive oxide as the first layer 54a of the lower electrode 54, the adhesion between the lower electrode 54 and the lower layer 53 is improved, and the Bi layered ferroelectric film 55 such as Si in the lower layer 53 is formed. Can be prevented from spreading.

[Effects] Abnormal precipitates such as hillocks do not exist at the interfaces of the Bi layered ferroelectric film 55, the third layer 54c of the lower electrode 54, and the first layer 56a of the upper electrode 56. Since it is possible to prevent electric field concentration that occurs when a voltage is applied between the lower electrodes 54, it is possible to improve dielectric strength and fatigue resistance. Also, the third layer of the lower electrode 54
Since the crystal grain size of 54c is small and the variation is small and there is no hillock, the nucleation of the Bi layered ferroelectric film 55 during the heat treatment is uniform and good nucleation is performed. Body film 55 can be formed. further,
Since the elements in the Bi layered ferroelectric film 55 do not diffuse to the lower electrode 54 and the upper electrode 56, the composition of the Bi layered ferroelectric film 55 does not change, and a good Bi layered ferroelectric film 55 can be formed. Becomes In addition, since the adhesion between the lower electrode 54 and the lower layer 53 is good and the diffusion of Si or the like into the Bi layered ferroelectric film 55 can be suppressed, film peeling does not occur and the dielectric strength and dielectric constant are An improved dielectric thin film element can be obtained. Furthermore, the second layer 54b of the lower electrode 54 and the second layer 56 of the upper electrode 56.
By preventing the resistance from increasing by using Pt as b, the electrode resistance of the conventional dielectric thin film element can be maintained.

24. The conductive oxide of the first layer of the lower electrode is ITO, SnO ₂ , In ₂ O ₃ , RuO ₂ , RhO.
_2, ReO _2, OsO _2, wherein the 5, characterized in that its primary component at least one of the IrO _2. To the above 7. 13. To the above 15. 21. From 2
3. The dielectric thin film element described.

[Structure] The present invention is as follows:
2, 14, 19-21.

[Function] As a conductive oxide on the lower layer 53, ITO, SnO ₂ , In ₂ O ₃ , RuO ₂ , RhO ₂ ,
By using at least one of ReO ₂ , OsO ₂ , and IrO ₂ as a main component, the adhesiveness between the lower electrode 54 and the lower layer 53 is improved, and at the same time, the high and ferroelectric films such as Si in the lower layer 53 are formed. It is possible to prevent the diffusion to 55.

[Effect] Adhesiveness between the lower electrode 54 and the lower layer 53 is good, and high, since diffusion of Si or the like into the ferroelectric film 55 can be suppressed, film peeling does not occur, and high, ferroelectric It is possible to form an excellent ferroelectric film 55 having a high composition in which the composition of the body film 55 does not change. Therefore, a dielectric thin film element having improved dielectric strength and dielectric constant can be obtained.

[0257]

As described above in detail, according to the present invention, it is possible to provide a dielectric thin film element capable of improving withstand voltage, fatigue resistance and dielectric constant.

[Brief description of drawings]

FIG. 1 is an example of a dielectric thin film element according to the present invention, in which a substrate is composed of a Si substrate and an insulating film thereon.

FIG. 2 is an example of a dielectric thin film element according to the present invention, in which a substrate is composed of a Si substrate having a semiconductor diffusion region formed on the surface and an insulating film, and a lower electrode is directly connected to the semiconductor diffusion region.

FIG. 3 is an example of a dielectric thin film element according to the present invention, in which a substrate is composed of a Si substrate having a semiconductor diffusion region formed on the surface thereof, an insulating film, and a polycrystalline Si layer, and a lower electrode indirectly connected to the semiconductor diffusion region. What connects to.

FIG. 4 is an example of a dielectric thin film element according to the present invention, in which a substrate is composed of a Si substrate having a semiconductor diffusion region formed on the surface thereof, an insulating film and a polycrystalline Si layer, and a lower electrode indirectly connected to the semiconductor diffusion region. Modification when connecting to.

FIG. 5 is a schematic sectional view of a dielectric thin film element according to an embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of a dielectric thin film element showing one embodiment of the present invention, in which the lower electrode has a two-layer structure.

FIG. 7 is a schematic cross-sectional view of a dielectric thin film element showing one embodiment of the present invention, in which an upper electrode and a lower electrode each have a two-layer structure.

FIG. 8 is a schematic cross-sectional view of a dielectric thin film element showing one embodiment of the present invention, in which the upper electrode has a two-layer structure and the lower electrode has a three-layer structure.

FIG. 9 is a schematic cross-sectional view of a conventional dielectric thin film element.

[Explanation of symbols]

 1, 21, 31, 41, 51 ... Substrate, 4, 54 ... Lower electrode, 5, 55 ... High, ferroelectric film, 6, 56 ... Upper electrode, 7 ... Interlayer insulating film, 8 ... Wiring electrode, 54a, 56a ... first layer, 54b, 56b ... second layer, 54c ... third layer.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H01L 29/792

Claims (3)

[Claims] 1. A dielectric having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film. A thin film element, wherein the lower electrode is made of Pt containing at least one element of Rh, Ru, Os, and Ir. 2. A dielectric having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film. In the thin film element, the lower electrode is composed of a first layer formed on the substrate and a second layer formed thereon and in contact with the high and ferroelectric films, and the first layer of the lower electrode is Pt. And the second layer of the lower electrode is made of Ph, Ru, Os, Ir
A dielectric thin film element comprising Pt containing at least one element of Pt. 3. A dielectric having a lower electrode formed on a substrate, a high ferroelectric film formed on the lower electrode, and an upper electrode formed on the high ferroelectric film. In the thin film element, the lower electrode is composed of a first layer formed on the substrate and a second layer formed thereon and in contact with the high and ferroelectric films, and the first layer of the lower electrode is Pt. And the second layer of the lower electrode is made of Pt containing at least one element of Rh, Ru, Os and Ir, and the upper electrode is a first layer formed on the high ferroelectric film. And a second layer formed thereon, wherein the first layer of the upper electrode is Pt containing at least one element of Rh, Ru, Os and Ir, and the second layer of the upper electrode Is a Pt dielectric film element.