JP6825085B2 - Manufacturing method of resistance changing element and resistance changing element - Google Patents

Description

The present invention relates to a method for manufacturing a resistance changing element and a resistance changing element.

Semiconductor memory includes volatile memory such as DRAM (Dynamic Random Access Memory) and non-volatile memory such as flash memory. NAND flash memory is the mainstream as a non-volatile memory, but the design rule after 20 nm sets the limit of miniaturization, and ReRAM (Resistance RAM) is attracting attention as a device capable of further miniaturization.

The conventional ReRAM has a structure in which a metal oxide layer having a desired resistance value is sandwiched between upper and lower platinum (Pt) electrode layers, and a voltage is applied to the upper electrode layer to change the resistance of the metal oxide layer. Therefore, memory switching is performed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-207130

However, since Pt used as a material for the electrode layer is an expensive metal, it is necessary to develop an electrode material having excellent electrical characteristics at low cost in order to reduce the cost of the resistance changing element and improve the productivity. ing.

In view of the above circumstances, an object of the present invention is to provide a method for manufacturing a resistance changing element having excellent electrical characteristics at low cost and a resistance changing element.

In order to achieve the above object, the method for manufacturing a resistance changing element according to an embodiment of the present invention includes forming a first titanium nitride electrode layer on a substrate. A first metal oxide layer having a first resistivity is formed on the first titanium nitride electrode layer. A second metal oxide layer having a second resistivity different from the first resistivity is formed on the first metal oxide layer. A second titanium nitride electrode layer is formed on the second metal oxide layer by a sputtering method while applying a bias voltage to the substrate.
According to the method for manufacturing such a resistance changing element, a high-density second titanium nitride electrode layer is formed on the second metal oxide layer while applying a bias voltage to the substrate, so that the cost is low. A resistance changing element having excellent electrical characteristics is formed.

In the manufacturing method of the variable resistance element, the step of forming the second titanium nitride electrode layer may include applying a bias power of 0.03 W / cm ² or more 0.62 W / cm ² or less on the substrate It may be.
According to the manufacturing method of the variable resistance element, while applying a 0.03 W / cm ² or more 0.62 W / cm ² or less of the bias voltage to the substrate, a high density on the second metal oxide layer Since the second titanium nitride electrode layer of the above is formed, a resistance changing element having excellent electrical characteristics is formed at low cost.

The method for manufacturing the resistance changing element may include a step of forming the second metal oxide layer with a film thickness of 3 nm or more and 11 nm or less.
According to such a method for manufacturing a resistance changing element, the second metal oxide layer is formed with a film thickness of 3 nm or more and 11 nm or less, so that a resistance changing element having excellent electrical characteristics is formed at low cost.

In the method for manufacturing the resistance changing element, the step of forming the second titanium nitride electrode layer uses a mixed gas of a rare gas and a nitrogen gas as the sputtering gas, and the nitrogen gas is used with respect to the total flow rate of the mixed gas. The flow rate may include being 10% or more and 100% or less.
According to the method for manufacturing such a resistance changing element, the flow rate of the nitrogen gas with respect to the total flow rate of the mixed gas is adjusted to 10% or more and 100% or less while applying a bias voltage to the substrate, and the second metal Since the high-density second titanium nitride electrode layer is formed on the oxide layer, a resistance changing element having excellent electrical characteristics is formed at low cost.

In the method for manufacturing the resistance changing element, the step of forming the second titanium nitride electrode layer may include adjusting the temperature of the substrate to 20 ° C. or higher and 320 ° C. or lower.
According to the method for manufacturing such a resistance changing element, the temperature of the substrate is adjusted to 20 ° C. or higher and 320 ° C. or lower while applying a bias voltage to the substrate, so that the temperature of the substrate is adjusted to 20 ° C. or higher and 320 ° C. or lower. Since the second titanium nitride electrode layer having a high density is formed, a resistance changing element having excellent electrical characteristics is formed at low cost.

In the method for manufacturing the resistance changing element, the pressure of the mixed gas may be adjusted to 0.1 Pa or more and 1 Pa or less.
According to the method for manufacturing such a resistance changing element, the pressure of the mixed gas is adjusted to 0.1 Pa or more and 1 Pa or less while applying a bias voltage to the substrate, and is high on the second metal oxide layer. Since the second titanium nitride electrode layer having a high density is formed, a resistance changing element having excellent electrical characteristics is formed at low cost.

In order to achieve the above object, the resistance changing element according to one embodiment of the present invention includes a first titanium nitride electrode layer, a second titanium nitride electrode layer, and an oxide semiconductor layer. The oxide semiconductor layer is provided between the first titanium nitride electrode layer and the second titanium nitride electrode layer. The oxide semiconductor layer has a first metal oxide layer having a first resistivity and a second metal oxide layer having a second resistivity different from the first resistivity. The second metal oxide layer is provided between the first metal oxide layer and the second titanium nitride electrode layer. The second titanium nitride electrode layer has a density of 4.8 g / cm ³ or more and 5.5 g / cm ³ or less.
According to such a method for manufacturing a resistance changing element, a high-density second titanium nitride electrode layer is formed on the second metal oxide layer, so that a resistance changing element having excellent electrical characteristics at low cost can be obtained. It is formed.

As described above, according to the present invention, there is provided a method for manufacturing a resistance changing element having excellent electrical characteristics at low cost and a resistance changing element.

It is the schematic sectional drawing which shows the structure of the resistance change element which concerns on this embodiment. It is a graph of the current-voltage characteristic when TiN is used for the upper electrode layer and the lower electrode layer in the resistance change element which concerns on a comparative example. It is a graph of the current-voltage characteristic of the resistance change element which concerns on this embodiment. It is a graph which shows the relationship between the RF bias power and the density of a titanium nitride electrode layer. It is a graph which shows the relationship between the ratio of the nitrogen gas flow rate with respect to the mixed gas flow rate, and the density of a titanium nitride electrode layer. It is a graph which shows the relationship between the substrate temperature and the density of a titanium nitride electrode layer. It is a figure which shows the correlation of the electric property with the film thickness of the 2nd metal oxide layer, and the RF bias electric power when forming TiN as an upper electrode layer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. XYZ axis coordinates may be introduced in each drawing.

FIG. 1 is a schematic cross-sectional view showing the configuration of the resistance changing element according to the present embodiment.

The resistance changing element 1 shown in FIG. 1 includes a substrate 2, a lower electrode layer 3 (first titanium nitride electrode layer), an oxide semiconductor layer 4, and an upper electrode layer 5 (second titanium nitride electrode layer). To do.

As the substrate 2, a semiconductor substrate such as a silicon wafer is typically used, but the substrate 2 is not limited to this, and an insulating ceramic substrate such as a glass substrate may be used.

The oxide semiconductor layer 4 is provided between the lower electrode layer 3 and the upper electrode layer 5. The oxide semiconductor layer 4 has a first metal oxide layer 41 and a second metal oxide layer 42. The first metal oxide layer 41 and the second metal oxide layer 42 are each made of the same kind of material, but may be made of different materials. The resistivity of the first metal oxide layer 41 (first resistivity) is different from the resistivity of the second metal oxide layer 42 (second resistivity).

Of the first metal oxide layer 41 and the second metal oxide layer 42, one is composed of an oxide material having a stoichiometric composition (hereinafter, also referred to as “stoichiometric composition material”), and the other is composed of an oxide material having a stoichiometric composition. It is composed of an oxide material containing a large number of oxygen deficiencies (hereinafter, also referred to as "oxygen deficient material"). In the present embodiment, the first metal oxide layer 41 is composed of an oxygen-deficient material, and the second metal oxide layer 42 is composed of a stoichiometric composition material.

The first metal oxide layer 41 is formed on the lower electrode layer 3 and contains tantalum (Ta) and oxygen (O). For example, the first metal oxide layer 41 is formed of tantalum oxide (TaO _x ) in this embodiment. The tantalum pentoxide used for the first metal oxide layer 41 has a lower degree of oxidation than the tantalum oxide forming the second metal oxide layer 42, and its resistivity is larger than, for example, 1 Ω · cm, and is 1 × 10 ^6. It is Ω · cm or less.

The material constituting the first metal oxide layer 41 is not limited to the above, and for example, zirconium oxide (ZrO _x ), hafnium oxide (HfO _x ), yttrium oxide (YO _x ), titanium oxide (TiO _x ), aluminum oxide ( AlO _x ), silicon oxide (SiO _x ), iron oxide (FeO _x ), nickel oxide (NiO _x ), cobalt oxide (CoO _x ), manganese oxide (MnO _x ), tin oxide (SnO _x ), zinc oxide (ZnO) _x ), vanadium oxide (VO _x ), tungsten oxide (WO _x ), copper oxide (CuO _x ), Pr (Ca, Mn) O ₃ , LaAlO ₃ , SrTIO ₃ , La (Sr, Mn) O _3, etc. A primordial or ternary or higher oxide material is used.

The second metal oxide layer 42 is formed on the first metal oxide layer 41 and contains tantalum (Ta) and oxygen (O). For example, in this embodiment, the second metal oxide layer 42 is formed of tantalum oxide (Ta ₂ O ₅ ). The tantalum oxide used in the second metal oxide layer 42 has a stoichiometric composition or a composition close to it, and has a resistivity larger than, for example, 1 × 10 ⁶ (1E + 06) Ω · cm. The material constituting the second metal oxide layer 42 is not limited to this, and a binary system or a ternary system or higher oxide material as described above can be applied.

The first metal oxide layer 41 and the second metal oxide layer 42 can be formed, for example, by a reactive sputtering method with oxygen. In the present embodiment, the metal (Ta) target is sputtered in a vacuum chamber into which oxygen has been introduced to sequentially form metal oxide layers 41 and 42 made of tantalum oxide on the substrate 2 (lower electrode layer 3). The degree of oxidation of each of the metal oxide layers 41 and 42 is controlled by the flow rate (partial pressure) of oxygen introduced into the vacuum chamber.

Since the second metal oxide layer 42 has a higher degree of oxidation than the first metal oxide layer 41, the resistivity of the second metal oxide layer 42 is higher than the resistivity of the first metal oxide layer 41. Here, when a negative voltage is applied to the upper electrode layer 5 and a positive voltage is applied to the lower electrode layer 3, oxygen ions (O ^2- ) in the second metal oxide layer 42 having high resistance (high oxygen density) have low resistance. It diffuses into the first metal oxide layer 41, and the resistance of the second metal oxide layer 42 decreases. This state is a low resistance state.

On the other hand, when the voltage applied to the lower electrode layer 3 and the upper electrode layer 5 is inverted from the low resistance state and a negative voltage is applied to the lower electrode layer 3 and a positive voltage is applied to the upper electrode layer 5, the first metal oxide is applied. Oxygen ions diffuse from the layer 41 to the second metal oxide layer 42, the degree of oxidation of the second metal oxide layer 42 increases again, and the resistance increases. This state is a high resistance state.

As described above, the oxide semiconductor layer 4 reversibly switches between the low resistance state and the high resistance state by controlling the voltage between the lower electrode layer 3 and the upper electrode layer 5. Further, since the low resistance state and the high resistance state are maintained even when no voltage is applied, the resistance changing element 1 is non-volatile, such as writing data in the high resistance state and reading data in the low resistance state. It can be used as a memory element.

A noble metal such as Pt may be used as a material for the upper electrode layer and the lower electrode layer of the resistance changing element because they have high corrosion resistance and good conductivity. However, precious metals such as Pt are expensive, and microfabrication such as etching is difficult, so that they are not suitable for mass production. Therefore, in order to reduce the cost of the resistance changing element and improve the productivity, an electrode layer having a low cost and good electrical characteristics is required.

On the other hand, TiN is cheaper than precious metals such as Pt. Further, TiN can be finely processed such as etching, and is suitable for mass production. However, since the oxide semiconductor layer 4 contains oxygen, when a metal other than the noble metal is used as the electrode layer, the oxygen of the oxide semiconductor layer 4 may diffuse into the electrode layer.

FIG. 2 is a graph of current-voltage characteristics when TiN is used for the upper electrode layer and the lower electrode layer in the resistance changing element according to the comparative example. FIG. 2 shows a current-voltage curve when writing and erasing the resistance changing element.

Here, the horizontal axis of FIG. 2 shows the voltage applied to the upper electrode layer 5, and the vertical axis shows the current value flowing between the upper electrode layer 5 and the lower electrode layer 3. A low current value means that the oxide semiconductor layer is in a high resistance state, and a high current value means that the oxide semiconductor layer is in a low resistance state.

When a film was formed using TiN as an upper electrode layer by a sputtering method, it is known that a highly insulating film (TiNO film) is formed at the interface between the TiN upper electrode layer and the oxide semiconductor layer by nitrogen plasma. It is considered that one of the factors for forming such a highly insulating film is that oxygen diffusion is likely to occur at the grain boundaries of the TiN upper electrode layer when the density of the TiN upper electrode layer is not sufficiently high. Be done. Here, in the comparative example, the TiN upper electrode layer is formed without applying a bias voltage to the substrate 2 during sputtering.

When such a highly insulating film is formed, in order to use it as a resistance changing element, a high switching operating voltage is applied to the oxide semiconductor layer to cause an element initialization process (which causes a phenomenon similar to dielectric breakdown). Forming) is required. It is considered that the switch operation of the oxide semiconductor layer is expressed by generating a current path called a filament in the oxide semiconductor layer by forming.

However, when a film having high insulating properties is formed in the oxide semiconductor layer, the size and position of the filament cannot be appropriately controlled by forming, so that the forming voltage may increase. Further, the filament formed by the high forming voltage tends to be thick, and after the forming operation, the resistance of the oxide semiconductor layer becomes low, and the on / off ratio of the resistance changing element may not be good. For example, in the example of FIG. 2, the forming voltage when forming the oxide semiconductor layer in the initial state (high resistance state) is about 2.5V.

On the other hand, if the density of the TiN upper electrode layer is increased, the grain boundaries of the TiN upper electrode layer are reduced or the grain boundaries are narrowed, and it is considered that oxygen diffusion from the oxide semiconductor layer to the TiN upper electrode layer is less likely to occur. Therefore, the present inventors have found an upper electrode layer 5 in which oxygen in the oxide semiconductor layer is less likely to diffuse into the TiN upper electrode layer by controlling the density of the TiN upper electrode layer.

Examples of the method of forming the high-density TiN upper electrode layer include a method of forming by an RF sputtering method or a pulse DC sputtering method while applying a bias voltage to the substrate 2. A titanium (Ti) target is used as the target in each sputtering method, and a TiN upper electrode layer is formed on the second metal oxide layer 42 by the reactive sputtering method. Examples of the reaction gas include nitrogen (N ₂ ) or a mixed gas of nitrogen (N ₂ ) and argon (Ar). The details of the method of forming the TiN upper electrode layer will be described together with the method of manufacturing the resistance changing element 1 described later.

The density of the TiN upper electrode layer formed by the above method is relatively high, 4.8 g / cm ³ or more and 5.5 g / cm ³ or less. For example, when the density of the TiN upper electrode layer is smaller than 4.8 g / cm ³ , oxygen is easily diffused from the second metal oxide layer 42 to the grain boundaries of the TiN upper electrode layer, and the TiN upper electrode layer and the oxide A highly insulating film (TiNO film) is formed at the interface with the semiconductor layer, which is not preferable.

FIG. 3 is a graph of the current-voltage characteristics of the resistance changing element according to the present embodiment.

As shown in FIG. 3, in the resistance changing element 1 according to the present embodiment, the forming voltage is suppressed as compared with the comparative example, and is about 1.5V. Further, in the resistance changing element according to the present embodiment, the on / off ratio is also better than that of the comparative example.

As described above, according to the resistance changing element 1 according to the present embodiment, since the upper electrode layer 5 is made of TiN, the cost is compared with the case where the upper electrode layer is made of a precious metal material such as Pt. Can be reduced. Further, the density of the TiN upper electrode layer, which is the upper electrode layer 5, is high, and it becomes difficult for the upper electrode layer 5 to permeate and absorb oxygen in the oxide semiconductor layer 4, and the extraction of oxygen in the oxide semiconductor layer 4 is suppressed. Will be done. This makes it possible to prevent the oxide semiconductor layer 4 from having a low resistance. As a result, the switching characteristics of the resistance changing element are improved.

A method of manufacturing the resistance changing element 1 will be described.

First, the lower electrode layer 3 (first titanium nitride electrode layer) is formed on the wafer-shaped substrate 2. The lower electrode layer 3 is formed under the same conditions as the upper electrode layer 5 (second titanium nitride electrode layer) described later. The density of the lower electrode layer 3 is, for example, the same as the density of the upper electrode layer 5. As a result, TiNO is less likely to be formed at the interface between the lower electrode layer 3 and the oxide semiconductor layer 4, and good electrical characteristics can be obtained. The thickness of the upper electrode layer 5 is not particularly limited, and is, for example, 50 nm.

In the lower electrode layer 3, the grain boundaries are controlled and it is preferable that the lower electrode layer 3 is flat. As a result, the upper layer of the lower electrode layer 3 becomes flatter. To form the lower electrode layer 3 more flatly, for example, the lower electrode layer 3 is formed while controlling the temperature of the substrate 2 to room temperature or a temperature close to room temperature.

Next, the oxide semiconductor layer 4 is formed on the lower electrode layer 3.

First, as the first metal oxide layer 41, a tantalum oxide layer having a smaller amount of oxygen than the stoichiometric composition is formed by, for example, a vacuum deposition method, a sputtering method, a CVD method, an ALD method, or the like. The thickness of the oxide semiconductor layer 4 is not particularly limited, and is, for example, 20 nm. In the present embodiment, the first metal oxide layer 41 is formed by reactive sputtering with oxygen.

Subsequently, the second metal oxide layer 42 is formed on the first metal oxide layer 41. In the present embodiment, as the second metal oxide layer 42, a tantalum oxide layer having a stoichiometric composition or an oxygen composition ratio close to that is formed. The thickness of the second metal oxide layer 42 is not particularly limited, and is, for example, 3 nm or more and 11 nm or less. The film forming method is not particularly limited, and is produced by, for example, a vacuum deposition method, a sputtering method, a CVD method, an ALD method, or the like. In this embodiment, the second metal oxide layer 42 is formed by reactive sputtering with oxygen.

Next, the upper electrode layer 5 is formed on the oxide semiconductor layer 4. In the present embodiment, the TiN upper electrode layer is formed as the upper electrode layer 5 by RF sputtering or pulse DC sputtering. The thickness of the TiN upper electrode layer is not particularly limited, and is, for example, 50 nm.

The conditions for RF sputtering are not particularly limited, and are carried out under the following conditions, for example.
Gas flow rate: 50 [sccm]
Titanium target input power: 2 [W / cm ² ]
RF frequency: 13.56 [MHz]

The conditions for pulse DC sputtering are not particularly limited, and are carried out under the following conditions, for example.
Gas flow rate: 50 [sccm]
Titanium target input power: 2 [W / cm ² ]
Pulse DC frequency: 20 [kHz]

In each sputtering, as the substrate 2, a silicon wafer having a diameter of 300 mm, the RF bias power 0.03 W / cm ² or more 0.62 W / cm ² or less, the ratio of the nitrogen gas flow rate to the flow rate of the mixed gas of 10% or more By controlling the substrate temperature to 100% or less, the substrate temperature to 20 ° C. or more and 320 ° C. or less, and the film formation pressure to 0.1 Pa or more and 1 Pa or less, the density of the TiN upper electrode layer is 4.8 g / cm ³ or more and 5.5 g / cm ³ It is adjusted as follows. As a result, the resistance changing element 1 having good switching characteristics is manufactured.

For example, FIG. 4 is a graph showing the relationship between the RF bias power and the density of the titanium nitride electrode layer. Here, the ratio of the nitrogen gas flow rate to the mixed gas flow rate is 26%, the substrate temperature is 20 ° C., and the film formation pressure is 0.27 Pa.

In the example of FIG. 4, when 20 W (0.03 W / cm ² ) is applied as the RF bias power, the density of the titanium nitride electrode layer becomes 4.8 g / cm ³ or more. Then, when the RF bias power is further increased, the density of the titanium nitride electrode layer gradually increases, and the density becomes about 5.4 g / cm ³ . Thus, RF bias power is preferably controlled by the 0.03 W / cm ² or more 0.62 W / cm ² or less in the range, it is preferable that the second metal oxide layer is set to 11nm or less in the range of 3nm ..

Further, FIG. 5 is a graph showing the relationship between the ratio of the nitrogen gas flow rate to the mixed gas flow rate and the density of the titanium nitride electrode layer. Here, the substrate temperature is 20 ° C., and the film formation pressure is 0.27 Pa.

In the example of FIG. 5, by controlling the ratio of the nitrogen gas flow rate to the mixed gas flow rate at 10% or more and 100% or less, the density of the titanium nitride electrode layer is 4.8 g / cm ³ or more and 5.5 g / cm ³ or less. It has been adjusted. As a result, the ratio of the nitrogen gas flow rate to the mixed gas flow rate is preferably controlled to be 10% or more and 100% or less. In particular, the ratio of the nitrogen gas flow rate to the mixed gas flow rate is 26%, and the density of the titanium nitride electrode layer is maximized.

Further, FIG. 6 is a graph showing the relationship between the substrate temperature and the density of the titanium nitride electrode layer. Here, the ratio of the nitrogen gas flow rate to the mixed gas flow rate is 26%, and the film formation pressure is 0.27 Pa.

In the example of FIG. 6, by controlling the substrate temperature to 20 ° C. or higher 320 ° C. or less, the density of the titanium nitride electrode layer is adjusted to 4.8 g / cm ³ or more 5.5 g / cm ³ or less. Thereby, the substrate temperature is preferably controlled to 20 ° C. or higher and 320 ° C. or lower. However, when the substrate temperature exceeds 275 ° C., the surface of the titanium nitride electrode layer tends to be rough, and the substrate temperature is preferably 20 ° C. or higher and 275 ° C. or lower.

FIG. 7 is a chart showing the correlation between the thickness of the second metal oxide layer and the electrical characteristics of the RF bias power when forming TiN as the upper electrode layer.

Here, ⊚ indicates that switching was good and the forming voltage was almost unnecessary, ◯ indicates that both switching and forming voltage were good, Δ indicates that switching was good, and × indicates that switching was defective. Shows what was.

That is, when the thickness of the second metal oxide layer 42 was 3nm or more 11nm or less, if 0.03 W / cm ² or more 0.62 W / cm ² or less is the substrate bias value, switching and forming voltage both Good characteristics could be obtained. Further, when the film thickness of the second metal oxide layer 42 is 5 nm or more and 11 nm or less and the substrate bias value is 0.43 W / cm ² or more and 0.62 W / cm ² or less, almost no forming is required. We were able to.

This is because when the density of the TiN upper electrode layer is increased, the grain boundary of the TiN upper electrode layer is reduced or the grain boundary is narrowed, and oxygen diffusion from the oxide semiconductor layer to the TiN upper electrode layer is less likely to occur. It is presumed that filaments were formed by the defects generated in the second metal oxide layer 42 by the ion bomberment due to the predetermined substrate bias, and the forming became unnecessary.

The resistance changing element 1 formed on the wafer-shaped substrate 2 is formed to have a predetermined element size. Lithography and dry etching techniques may be used for patterning of each layer, lithography and wet etching techniques may be used, and each layer may be formed via a resist mask or the like. When the etching technique is used, the resistance changing element 1 may be built in the interlayer insulating film between the lower wiring layer and the upper wiring layer. Further, since the upper electrode layer 5 is formed at a high density, the upper electrode layer 5 can also be applied to a mask in the manufacturing process of the resistance changing element.

According to the above manufacturing method, since a highly insulating film is not formed at the interface between the upper electrode layer 5 and the second metal oxide layer 42, the voltage required for forming can be lowered, or forming is unnecessary. Become. This makes it possible to prevent an increase in the operating current of the element. Further, since the upper electrode layer 5 is difficult to permeate and absorb oxygen, the extraction of oxygen in the oxide semiconductor layer 4 is suppressed, and the resistance of the oxide semiconductor layer 4 can be prevented from being lowered. Therefore, the cost is low as compared with the case where a noble metal is used for the electrode layer, and it is possible to manufacture a resistance changing element having good switching characteristics.

There is a method of using DLC (diamond-like carbon) as the material of the upper electrode layer 5. In the present embodiment, by using TiN as the upper electrode layer 5, dust generation is suppressed as compared with DLC, and a lower resistance upper electrode layer is formed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made.

1 ... Resistance changing element 2 ... Substrate 3 ... Lower electrode layer 4 ... Oxide semiconductor layer 41 ... First metal oxide layer 42 ... Second metal oxide layer 5 ... Upper electrode

Claims (6)

A first titanium nitride electrode layer is formed on the substrate,
A first metal oxide layer having a first resistivity is formed on the first titanium nitride electrode layer.
A second metal oxide layer having a second resistivity different from the first resistivity is formed on the first metal oxide layer.
While applying a 0.43 W / cm ² or more 0.62 W / cm ² or less bias power to the substrate, the resistance change of forming by sputtering the second titanium nitride electrode layer over the second metal oxide layer Method of manufacturing the element. The method for manufacturing a resistance changing element according to claim 1 .
The step of forming the second metal oxide layer includes a step of forming the second metal oxide layer with tantalum oxide and forming the second metal oxide layer with a film thickness of 5 nm or more and 11 nm or less. Manufacturing method of changing element. The method for manufacturing a resistance changing element according to claim 1 or 2 .
In the step of forming the second titanium nitride electrode layer, a mixed gas of a rare gas and a nitrogen gas is used as the sputtering gas, and the flow rate of the nitrogen gas with respect to the total flow rate of the mixed gas is 10% or more and 100% or less. A method of manufacturing a resistance changing element including the above. The method for manufacturing a resistance changing element according to any one of claims 1 to 3 .
The step of forming the second titanium nitride electrode layer is a method for manufacturing a resistance changing element, which comprises adjusting the temperature of the substrate to 20 ° C. or higher and 320 ° C. or lower. The method for manufacturing a resistance changing element according to claim 3 .
A method for manufacturing a resistance changing element, which comprises adjusting the pressure of the mixed gas to 0.1 Pa or more and 1 Pa or less. The first titanium nitride electrode layer and
The second titanium nitride electrode layer and
A first metal oxide layer provided between the first titanium nitride electrode layer and the second titanium nitride electrode layer and having a first resistivity, the first metal oxide layer and the second titanium nitride electrode. It is provided with an oxide semiconductor layer provided between the layers and having a second metal oxide layer having a second resistivity different from the first resistivity.
The second metal oxide layer is tantalum oxide having a film thickness of 5 nm or more and 11 nm or less.
The second titanium nitride electrode layer is a resistance changing element having a density of 4.8 g / cm ³ or more and 5.5 g / cm ³ or less.