KR20080038713A - Method of manufacturing capacitor using atomic layer deposition - Google Patents

Abstract

A method for manufacturing a capacitor using an atomic layer deposition method is provided to simplify a manufacturing process and to reduce thermal stress by removing a heat treatment process. A lower electrode(128) is formed on a substrate(100). A perovskite seed dielectric layer(130) is crystallized on the lower electrode by using an atomic layer deposition method. A bulk dielectric layer(131) is crystallized on the perovskite seed dielectric layer by using the atomic layer deposition method. An upper electrode(132) is formed on the bulk dielectric layer. The perovskite seed dielectric layer includes a strontium titanium oxide or a calcium titanium oxide.

Description

Method of manufacturing capacitor using atomic layer deposition

1 to 5 are cross-sectional views illustrating a capacitor manufacturing method according to an embodiment of the present invention.

6 is a graph showing the results of X-ray diffraction analysis of a composite dielectric film formed according to an embodiment of the present invention and a dielectric film formed according to the related art.

Explanation of symbols on the main parts of the drawings

100 semiconductor substrate 102 device isolation region

104: gate insulating film 106: polysilicon film

108 metal silicide film 110 gate electrode

112: capping insulating film 114: spacer

116a and 116b: source / drain regions 118: first insulating film

120: contact hole 122: contact plug

124: second insulating film 126: opening

128: lower electrode 130: seed dielectric film

131: bulk dielectric film 132: upper electrode

C: Capacitor

The present invention relates to a method of forming a capacitor of a semiconductor device using an atomic layer deposition (ALD) process. More particularly, the present invention relates to a method for forming a capacitor of a semiconductor device including a dielectric film made of a high dielectric constant material formed using an atomic layer deposition process.

In general, a decrease in cell capacitance due to the reduction of the memory cell area serves as a factor of inhibiting an increase in the degree of integration of a semiconductor memory device. The reduction in cell capacitance degrades the data readability of the semiconductor memory device and increases the soft error rate, making it difficult for the semiconductor memory device to operate at low voltages.

As an example of an effort to increase the cell capacitance, a method of thinning a dielectric film of a capacitor in order to increase the capacitance within a limited cell region, or forming a capacitor lower electrode having a structure such as a cylinder or a fin to form an effective area of the capacitor Increasing methods have been proposed. However, in dynamic random access memory (DRAM) of 1 gigabit or more, it is difficult to obtain a capacitance high enough to operate a memory device with these methods.

In order to solve this problem, in the manufacture of a dielectric film of a capacitor of a highly integrated semiconductor memory device having a design rule of 1 μm or less, a conventional nitride film, tantalum oxide (Ta ₂ O ₅ ) or alumina (Al ₂ O ₃ ) A dielectric film made of a material having a relatively higher dielectric constant such as an yttrium oxide film (Y ₂ O ₃ film), a hafnium oxide film (HfO ₂ film), a zirconium oxide film (ZrO ₂ film), and a niobium oxide film (Nb ₂ O ₅ film ), A method of using a strontium titanium oxide film (SrTiO ₃ film), a barium titanium oxide film (BaTiO ₃ film), or a barium strontium titanium oxide film ((Ba, Sr) TiO ₃ film) as a dielectric film of a capacitor has been actively studied.

In particular, the SrTiO ₃ film (hereinafter referred to as "STO film"), the BaTiO ₃ film (hereinafter referred to as "BTO film"), the (Ba, Sr) TiO ₃ film (hereinafter referred to as "BST film") Likewise, various attempts have been made to apply a material having a peroveskite crystal structure and a relatively high permittivity to a dielectric film of a capacitor. However, when the high dielectric constant material film having the perovskite crystal structure is in an amorphous state, a desired high dielectric constant cannot be obtained, so crystallization of the high dielectric constant material film is required.

The high dielectric constant perovskite material film may be formed using a sputtering method, a chemical vapor deposition method, or an atomic layer deposition method. In the case of using the sputtering method, a crystallized high permittivity perovskite material film may be formed, but since the step coverage is poor, it is not easy to apply to the lower electrode of a capacitor having a three-dimensional solid shape recently.

In addition, in the case of using the chemical vapor deposition method, a high process temperature is required to obtain a crystallized high dielectric constant perovskite material film, and uniform concentration of components in each position in the three-dimensional solid structure formed by the chemical vapor deposition. The disadvantage is that it can't be done. For example, in the case of the STO film or the BTO film, the concentration ratio of titanium to strontium or barium is preferably about 1, and in the case of the BST film, the concentration ratio between barium and strontium is about 1: 1. The concentration ratio of titanium to barium and strontium is preferably about 1. However, in the case of the high dielectric constant material film formed by chemical vapor deposition, there is a disadvantage in that the concentration ratio between the components constituting the film cannot be uniform.

In the case of using atomic layer deposition, the dielectric film crystallized at a relatively low temperature can be obtained in the case of the STO film or the CTO film (CaTiO ₃ film), but most of the perovskite crystal structure such as the BTO film or the BST film In the case of the dielectric film having N, it does not crystallize in a low temperature process. Therefore, when the BTO film or the BST film is formed, a separate heat treatment is required to crystallize it. However, the heat treatment may increase the thermal stress of the underlying film, and the productivity of the semiconductor device may be reduced by the additional heat treatment.

An object of the present invention for solving the above problems is to provide a method of manufacturing a capacitor comprising a perovskite dielectric film crystallized at a relatively low temperature.

According to an aspect of the present invention, there is provided a method of manufacturing a capacitor, including forming a lower electrode on a substrate, and using a perovskite seed dielectric layer crystallized using atomic layer deposition on the lower electrode. forming a perovskite seed dielectric layer, forming a crystallized perovskite bulk dielectric layer using atomic layer deposition on the seed dielectric layer, and forming an upper electrode on the bulk dielectric layer It may include the step.

According to one embodiment of the invention, the L perovskite oxide dielectric layer may comprise a strontium titanium oxide (SrTiO _3), or calcium titanium oxide (CaTiO _3).

According to an embodiment of the present disclosure, the forming of the seed dielectric layer may include supplying a first reactant including a strontium precursor on the lower electrode to form a strontium precursor layer on the lower electrode, and forming the strontium precursor. Supplying a second reactant including a titanium precursor on the film to form a titanium precursor film, and supplying an oxidant on the titanium precursor film to form a crystallized strontium titanium oxide film.

According to an embodiment of the present disclosure, the forming of the seed dielectric layer may include supplying a first reactant including a strontium precursor on the lower electrode to form a strontium precursor layer on the lower electrode, and forming the strontium precursor. Supplying an oxidant on the film to form a strontium oxide film, supplying a second reactant including a titanium precursor on the strontium oxide film to form a titanium precursor film, and supplying an oxidant on the titanium precursor film to crystallize It may comprise the step of forming a strontium titanium oxide film.

According to one embodiment of the invention, the bulk dielectric is barium titanium oxide (BaTiO _3), barium strontium titanium oxide _{((Ba, Sr) TiO 3} ), strontium titanium oxide (SrTiO _3), calcium titanium oxide (CaTiO ₃₎ , Barium strontium zirconium titanium oxide ((Ba, Sr) (Zr, Ti) O ₃ ), barium zirconium oxide (BaZrO ₃ ), and the like. These may be used alone or in the form of mixtures.

According to an embodiment of the present invention, the forming of the bulk dielectric layer may include supplying a first reactant including a barium precursor on the seed dielectric layer to form a barium precursor layer on the seed dielectric layer, and the barium precursor. The method may include supplying a second reactant including a titanium precursor on the film to form a titanium precursor film, and supplying an oxidant on the titanium precursor film to form a crystallized barium titanium oxide film.

According to an embodiment of the present invention, the forming of the bulk dielectric layer may include supplying a first reactant including a barium precursor on the seed dielectric layer to form a barium precursor layer on the seed dielectric layer, and the barium precursor. Supplying an oxidant on the film to form a barium oxide film, supplying a second reactant including a titanium precursor on the barium oxide film to form a titanium precursor film, and supplying an oxidant on the titanium precursor film Forming a crystallized barium titanium oxide film may be included.

According to an embodiment of the present invention, the forming of the bulk dielectric layer may include supplying a first reactant including a barium precursor on the seed dielectric layer to form a barium precursor layer on the seed dielectric layer, and the barium precursor. Supplying a second reactant including a strontium precursor onto a film to form a strontium precursor film on the barium precursor film, and supplying a third reactant including a titanium precursor onto the strontium precursor film to form a titanium precursor film And supplying an oxidant on the titanium precursor film to form a crystallized barium strontium titanium oxide film.

According to an embodiment of the present invention, the forming of the bulk dielectric layer may include supplying a first reactant including a barium precursor on the seed dielectric layer to form a barium precursor layer on the seed dielectric layer, and the barium precursor. Supplying an oxidant on the film to form a barium oxide film, supplying a second reactant including a strontium precursor on the barium oxide film to form a strontium precursor film on the barium oxide film, and on the strontium precursor film Supplying an oxidant to form a strontium oxide film, supplying a third reactant including a titanium precursor to the strontium oxide film to form a titanium precursor film, and supplying an oxidant to the titanium precursor film to crystallize barium strontium It may include forming a titanium oxide film.

According to an embodiment of the present invention, the forming of the bulk dielectric layer may include forming a barium strontium precursor layer on the seed dielectric layer by supplying a first reactant including a barium precursor and a strontium precursor on the seed dielectric layer; And supplying a second reactant including a titanium precursor on the barium strontium precursor film to form a titanium precursor film, and supplying an oxidant on the titanium precursor film to form a crystallized barium strontium titanium oxide film. Can be.

According to an embodiment of the present invention, the forming of the bulk dielectric layer may include forming a barium strontium precursor layer on the seed dielectric layer by supplying a first reactant including a barium precursor and a strontium precursor on the seed dielectric layer; Supplying an oxidant on the barium strontium precursor film to form a barium strontium oxide film, and supplying a second reactant including a titanium precursor to the barium strontium oxide film to form a titanium precursor film, and the titanium precursor film Supplying an oxidant to the phase may include forming a crystallized barium strontium titanium oxide film.

According to an embodiment of the present invention, the seed dielectric layer and the bulk dielectric layer may be formed at 300 to 400 ° C. The forming of the seed dielectric layer and the forming of the bulk dielectric layer may be performed in one process chamber. It can be formed in a tue manner.

According to the embodiments of the present invention as described above, the seed dielectric film is formed by atomic layer deposition can be crystallized during the deposition process, the bulk dielectric film is the seed dielectric film by atomic layer deposition on the crystallized seed dielectric film It is formed along the crystal lattice of and may be crystallized during the deposition process. Therefore, the heat treatment for crystallization of the seed dielectric film and the bulk dielectric film can be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments and may be implemented in other forms. The embodiments introduced herein are provided to make the disclosure more complete and to fully convey the spirit and features of the invention to those skilled in the art. In the drawings, the thickness of each device or film (layer) and regions has been exaggerated for clarity of the invention, and each device may have a variety of additional devices not described herein. When (layer) is mentioned as being located on another film (layer) or substrate, an additional film (layer) may be formed directly on or between the other film (layer) or substrate.

1 to 5 are cross-sectional views illustrating a capacitor manufacturing method according to an embodiment of the present invention.

Referring to FIG. 1, a gate insulating layer 104, a gate electrode 110, and source / drain regions 116a and 116b are formed on a semiconductor substrate 100 in which an active region 101 is defined by an isolation region 102. To form transistors comprising:

As the gate insulating layer 104, a silicon oxide film (SiO ₂ ), a silicon oxynitride film (SiON), a metal oxide film, or the like may be used. The gate insulating film 104 may be formed by about 10 kPa to 70 kPa by a conventional chemical vapor deposition process or an atomic layer deposition process. Can be. The metal oxide layer may be formed through an atomic layer deposition (ALD) process using a metal precursor and an oxidant such as oxygen (O ₂ ), ozone (O ₃ ), oxygen plasma, or the like.

The gate electrode 110 may have a polyside structure in which an impurity doped polysilicon layer 106 and a metal silicide layer 108 are sequentially stacked. Capping insulating layers 112 and spacers 114 made of silicon oxide or silicon nitride are formed on the top and sidewalls of the gate electrode 110, respectively. In addition, according to another embodiment of the present invention, the gate electrode 110 may include a metal nitride film and a metal film.

Referring to FIG. 2, after the first insulating layer 118 made of oxide is formed on the entire surface of the semiconductor substrate 100 on which the transistors are formed, the first insulating layer 118 is etched by a general photolithography process to form the source. A contact hole 120 is formed to partially expose the region 116a.

Subsequently, after depositing a first conductive layer (eg, an impurity doped polysilicon layer) on the contact hole 120 and the first insulating layer 118, the surface of the first insulating layer 118 is formed. The first conductive layer is removed by an etch back process or a chemical mechanical polishing (CMP) process so as to expose the contact plugs 122 in the contact hole 120.

Referring to FIG. 3, an etch stop layer 123 is formed on the contact plug 122 and the first insulating layer 118. The etch stop layer 123 may be formed of a material having a high etching selectivity with respect to the first insulating layer 118, for example, silicon nitride or silicon oxynitride.

After forming the second insulating layer 124 made of oxide on the etch stop layer 123, the opening 126 exposing the contact plug 122 is formed by etching the second insulating layer 124. Specifically, the second insulating layer 124 is partially etched until the etch stop layer 123 is exposed, and then excessively etched for a predetermined time to form an opening 126 that partially exposes the contact plug 122. do.

Subsequently, a second conductive layer 127 is formed on the side and bottom surfaces of the opening 126 and the second insulating layer 124. The second conductive layer 127 may be a rare metal such as impurity doped polysilicon, ruthenium (Ru), platinum (Pt), iridium (Ir), or an alloy thereof, titanium nitride (TiN), tantalum nitride (TaN), or tungsten. It may be formed using a conductive metal nitride such as nitride (WN).

Referring to FIG. 4, after a sacrificial layer (not shown) is formed on the second conductive layer 127, the sacrificial layer is formed on the second insulating layer 124 so that the surface of the second insulating layer 124 is exposed. The upper portion of the second conductive layer 127 and the upper portion of the sacrificial layer are removed by an etch back process or a chemical mechanical polishing process to form the lower electrode 128 of the capacitor having a three-dimensional structure.

The sacrificial layer and the second insulating layer 124 are removed by an isotropic or anisotropic etching process to expose the lower electrode 128 of the capacitor.

A perovskite seed dielectric layer 130 is formed on the lower electrode 128 to crystallize the bulk dielectric layer 131 such as a BTO thin film or a BST thin film to be subsequently formed. For example, using atomic layer deposition to form an STO (SrTiO ₃₎ thin film or a CTO (CaTiO ₃₎ the thin film can be crystallized at a low temperature with relatively.

Hereinafter, a method of forming the STO thin film will be described in detail.

First, the substrate 100 on which the lower electrode 128 is formed is positioned inside a chamber for atomic layer deposition, and the substrate 100 is processed at a process temperature of about 300 to 400 ° C., for example, about 350 ° C. Heated to a temperature of. When the temperature of the substrate is lower than 300 ° C, the STO thin film may not be crystallized. When the temperature of the substrate 100 is higher than 400 ° C, the thickness control of the STO thin film is not easy, and thus the STO The step coverage of the thin film may be poor. In addition, it is not easy to control the composition ratio between strontium and titanium in the STO thin film. In particular, it is difficult to adjust the composition ratio for each position on the lower electrode 128 of the three-dimensional structure.

Subsequently, a first reactant including a strontium precursor is supplied onto the substrate 100 on which the lower electrode 128 is formed to form a strontium precursor film on the lower electrode 128. The first reactant includes a gaseous or liquid strontium precursor, and the gaseous strontium precursor may be carried into the chamber by an inert gas such as argon or nitrogen. In addition, the liquid first reactant may be provided into the chamber through a liquid delivery system (LDS) and a vaporizer. At this time, the strontium precursor vaporized in the vaporization system may be carried into the chamber by an inert gas.

Examples of the strontium precursor include Sr (C ₅ ⁱ Pr ₃ H ₂ ) ₂ , SrS, Sr (thd) ₂ (thd = 2, 2, 6, 6-tetramethyl-3, 5-heptanedione), Sr (acac) ₂ , Sr (hfac) ₂ , Sr (tfac) ₂ , Sr (TMFD) ₂ , [Sr (TMHD) ₂ ] L (L: lewis base), Sr (tmhd) ₂ (tetraglyme), Sr (tmhd) ₂ (pmdeta ), [Sr (acac) ₂ ] L (L: lewis base), Sr (dmp) ₂ , Sr (metmhd) ₂ , Sr (tmhd) ₂ (trine) n and the like. On the other hand, an organic solvent such as tetrahydrofuran (THF) may be used to transport the liquid or solid strontium precursor to the vaporization system.

A portion of the first reactant may be chemically adsorbed onto the upper electrode 128, and the remainder of the first reactant may be physically adsorbed onto or suspended in the chamber on the chemically adsorbed first reactant. can do.

After the supply of the first reactant is stopped, the chamber is evacuated while supplying a purge gas into the chamber, thereby removing the physically adsorbed first reactant and the first reactant suspended in the chamber. Accordingly, a strontium precursor film may be formed on the lower electrode 128. As the purge gas, an inert gas such as nitrogen or argon may be used.

Subsequently, a second reactant including a titanium precursor is supplied onto the substrate 100 on which the strontium precursor film is formed to form a titanium precursor film on the strontium precursor film.

The second reactant may comprise a gaseous titanium precursor and may be carried by an inert gas such as nitrogen or argon. The vapor phase titanium precursor gas may also be provided through a bubbling system or a liquid delivery system and a vaporization system.

Examples of the titanium precursor include Ti (O ⁱ Pr) ₄ , Ti (TMHD) ₂ (O ⁱ Pr) ₂ , Ti (acac) ₄ , Ti (thac) ₂ (O ⁱ Pr) ₂ , Ti (hfac) ₂ ( O ⁱ Pr) ₂ , Ti (TMHD) ₂ (O ⁿ Bu) ₂ , Ti (acac) ₂ (O ⁿ Bu) ₂ , Ti (tfac) ₂ (O ⁿ Bu) ₂ , Ti (hfac) ₂ (O ⁿ Bu) ₂ , Ti (TMHD) ₂ (NMe ₂ ) ₂ , Ti (TMHD) ₂ (dmae), Ti (Nme ₂ ) ₄ , Ti (NEt ₂ ) ₄ , Ti (dmea) ₄ , Ti (dmea) ₂ ( ⁱ PrO) ₂ , Ti (hfac) ₂ (nBuO) ₂ , Ti (tfac) ₂ (nBuO) ₂ , Ti (acac) ₂ (nBuO) ₂ , Ti (TMHD) ₂ (nBuO) ₂ , Ti (TMHD) ₂ (iPrO) ₂ , Ti (hfac) ₂ ( ⁱ PrO) ₂ , Ti (tfac) ₂ ( ⁱ PrO) ₂ , Ti (acac) ₂ ( ⁱ PrO) ₂ , Ti (tmhd) ₂ (mpd), and the like. have.

A portion of the second reactant may be chemically adsorbed on the strontium precursor film, and the remainder of the second reactant may be physically adsorbed on or suspended in the chamber on the chemically adsorbed second reactant. have.

After the supply of the second reactant is stopped, the chamber is evacuated while supplying a purge gas into the chamber to remove the physically adsorbed second reactant and the second reactant suspended in the chamber. Accordingly, a titanium precursor film may be formed on the strontium precursor film. As the purge gas, an inert gas such as nitrogen or argon may be used.

The ratio between the first cycle of supplying the first reactant and the purge gas to form the strontium precursor film and the second cycle of supplying the second reactant and the purge gas to form the titanium precursor film is from 1: 10 to 10. : Can be adjusted to 1 degree. In particular, the cycle ratio may be adjusted so that the concentration ratio of strontium and titanium is about 1: 1.

Subsequently, an oxidant is supplied onto the substrate 100 on which the strontium precursor film and the titanium precursor film are formed to form an STO thin film (strontium titanium oxide film) by an oxidation reaction between the strontium precursor film, the titanium precursor film and the oxidant. In particular, since the STO thin film may have a perovskite crystal structure by the oxidation reaction, a separate heat treatment for crystallizing the STO thin film is not required.

Subsequently, a purge gas for removing the reaction by-products and residual oxidant by the oxidation reaction is provided, and the reaction by-products and residual oxidant may be evacuated together with the purge gas. Meanwhile, oxygen (O ₂ ), ozone (O ₃ ), oxygen plasma, or the like may be used as the oxidant.

As described above, the steps for forming the STO thin film used as the seed dielectric layer 130 may be repeatedly performed until a desired thickness, for example, a thickness of about 45 to 55 mm 3 is realized.

According to another embodiment of the present invention, the STO thin film may be formed through the following steps.

First, a strontium precursor film is formed on the substrate 100 by using a first reactant including a strontium precursor. Further details of the method of forming the strontium precursor film are substantially the same as described above, and thus will be omitted.

An oxidant is supplied onto the strontium precursor film to form a strontium oxide film on the lower electrode 128.

A titanium precursor film is formed on the strontium oxide film using a second reactant including a titanium precursor. Further details of the method of forming the titanium precursor film are omitted since they are substantially the same as described above.

An oxidant is supplied onto the titanium precursor film to form an STO thin film by an oxidation reaction between the strontium oxide film, the titanium precursor film, and the oxidant. Since the STO thin film may have a perovskite crystal structure by the oxidation reaction, a separate heat treatment for crystallizing the STO thin film is not required.

A perovskite bulk dielectric film 131 such as a BTO thin film or a BST thin film is formed on the crystallized STO thin film, that is, the seed dielectric film 130 by atomic layer deposition. In accordance with another embodiment of the invention, the bulk dielectric layer 131 is strontium titanium oxide (SrTiO _3), calcium titanium oxide (CaTiO _3), barium strontium zirconium titanium oxide ((Ba, Sr) (Zr, Ti) O ₃ ), Barium zirconium oxide (BaZrO ₃ ), and the like. These may be used alone or in the form of mixtures.

Hereinafter, the method of forming the BTO thin film will be described in detail.

A third reactant including a barium precursor is supplied onto the substrate 100 on which the crystalline STO thin film is formed to form a barium precursor film on the STO thin film. The third reactant includes a gaseous barium precursor and may be carried by an inert gas such as argon or nitrogen. Meanwhile, the liquid third reactant may be provided through a liquid delivery system and a vaporizer.

Examples of the barium precursor include Ba (DPM) ₂ , Ba (O ₂ C ₂ H (C ₂ H ₅ ) —C ₄ H ₉ ) ₂ , Ba (C ₅ Me ₅ ) ₂ , Ba (acac) ₂ , Ba ( tfac) ₂ , Ba (hfac) ₂ , Ba (tmhd) ₂ (tmhd = 2, 2, 6, 6-tetramethyl-3, 5-heptanedione), Ba (TMHD) ₂ (tetraglyme), Ba (tmhd) ₂ ( pmdeta), Ba (tmhd) ₂ (tetraen), Ba (metmhd) ₂ , Ba (tmhd) ₂ (trine) _n , Ba (TMHD) ₂ L (L: lewis base), Ba (acac) ₂ L and the like. Can be. On the other hand, an organic solvent such as tetrahydrofuran (THF) may be used to easily transport the liquid or solid barium precursor to the vaporization system.

A portion of the third reactant may be chemically adsorbed on the STO thin film, and the remainder of the third reactant may be physically adsorbed on the portion of the chemically adsorbed third reactant or suspended in the chamber. .

After the supply of the third reactant is stopped, the chamber is evacuated while supplying a purge gas into the chamber to remove the physically adsorbed third reactant and the third reactant suspended in the chamber. Accordingly, a barium precursor film may be formed on the STO thin film. As the purge gas, an inert gas such as nitrogen or argon may be used.

Subsequently, a fourth reactant including a titanium precursor is supplied onto the substrate on which the barium precursor film is formed to form a titanium precursor film on the barium precursor film.

The fourth reactant may comprise a gaseous titanium precursor and may be carried by an inert gas such as nitrogen or argon. The vapor phase titanium precursor gas may also be provided through a bubbling system or a liquid delivery system and a vaporization system.

Examples of the titanium precursor include Ti (O ⁱ Pr) ₄ , Ti (TMHD) ₂ (O ⁱ Pr) ₂ , Ti (acac) ₄ , Ti (thac) ₂ (O ⁱ Pr) ₂ , Ti (hfac) ₂ ( O ⁱ Pr) ₂ , Ti (TMHD) ₂ (O ⁿ Bu) ₂ , Ti (acac) ₂ (O ⁿ Bu) ₂ , Ti (tfac) ₂ (O ⁿ Bu) ₂ , Ti (hfac) ₂ (O ⁿ Bu) ₂ , Ti (TMHD) ₂ (NMe ₂ ) ₂ , Ti (TMHD) ₂ (dmae), Ti (Nme ₂ ) ₄ , Ti (NEt ₂ ) ₄ , Ti (dmea) ₄ , Ti (dmea) ₂ ( ⁱ PrO) ₂ , Ti (hfac) ₂ (nBuO) ₂ , Ti (tfac) ₂ (nBuO) ₂ , Ti (acac) ₂ (nBuO) ₂ , Ti (TMHD) ₂ (nBuO) ₂ , Ti (TMHD) ₂ (iPrO) ₂ , Ti (hfac) ₂ ( ⁱ PrO) ₂ , Ti (tfac) ₂ ( ⁱ PrO) ₂ , Ti (acac) ₂ ( ⁱ PrO) ₂ , Ti (tmhd) ₂ (mpd), and the like. have.

A portion of the fourth reactant may be chemically adsorbed onto the barium precursor film and the remainder of the fourth reactant may be physically adsorbed onto or suspended in the chamber on the chemically adsorbed fourth reactant. have.

After the supply of the fourth reactant is stopped, the chamber is evacuated while supplying a purge gas into the chamber to remove the physically adsorbed fourth reactant and the fourth reactant suspended in the chamber. Accordingly, a titanium precursor film may be formed on the barium precursor film. As the purge gas, an inert gas such as nitrogen or argon may be used.

The ratio between the third cycle of supplying the third reactant and the purge gas to form the barium precursor film and the fourth cycle of supplying the fourth reactant and the purge gas to form the titanium precursor film is from 1: 1 to 10. : Can be adjusted to 1 degree. In particular, the cycle ratio may be adjusted such that the concentration ratio of barium and titanium is about 1: 1.

Subsequently, an oxidant is supplied onto the substrate 100 on which the barium precursor film and the titanium precursor film are formed to form a BTO thin film (barium titanium oxide film) by an oxidation reaction between the barium precursor film, the titanium precursor film, and the oxidant. In particular, since the BTO thin film is formed using atomic layer deposition on the crystallized STO thin film, it may be crystallized according to the crystal structure of the STO thin film during the steps. Therefore, a separate heat treatment for crystallizing the BTO thin film is not required.

Subsequently, a purge gas for removing the reaction by-products and residual oxidant by the oxidation reaction is provided, and the reaction by-products and residual oxidant may be evacuated together with the purge gas. Meanwhile, oxygen (O ₂ ), ozone (O ₃ ), oxygen plasma, or the like may be used as the oxidant.

The steps for forming the BTO thin film as described above may be repeatedly performed until a desired thickness, for example, a thickness of about 145 to 250 mm 3 is achieved.

According to another embodiment of the present invention, the BTO thin film may be formed through the following steps.

First, a barium precursor film is formed on the substrate 100 by using a third reactant including a barium precursor. Further details of the method of forming the barium precursor film are omitted since they are substantially the same as described above.

An oxidant is supplied onto the barium precursor film to form a barium oxide film on the STO thin film.

A titanium precursor film is formed on the barium oxide film using a fourth reactant including a titanium precursor. Further details of the method of forming the titanium precursor film are omitted since they are substantially the same as described above.

An oxidant is supplied onto the titanium precursor film to form a BTO thin film by an oxidation reaction between the barium oxide film, the titanium precursor film, and the oxidant. Since the BTO thin film is formed using atomic layer deposition on the crystallized STO thin film, the BTO thin film may have the same crystal structure as the STO thin film. Therefore, a separate heat treatment for crystallizing the BTO thin film is not required.

According to another embodiment of the present invention, a BST thin film may be formed on the STO thin film. Hereinafter, a method of forming the BST thin film will be described in detail.

A barium precursor film is formed on the STO thin film by supplying a fifth reactant including a barium precursor onto the substrate 100 on which the STO thin film is formed. The fifth reactant includes a gaseous barium precursor and may be carried by an inert gas such as argon or nitrogen. In addition, the liquid fifth reactant may be provided through a liquid delivery system and a vaporization system.

Examples of the barium precursor include Ba (DPM) ₂ , Ba (O ₂ C ₂ H (C ₂ H ₅ ) —C ₄ H ₉ ) ₂ , Ba (C ₅ Me ₅ ) ₂ , Ba (acac) ₂ , Ba ( tfac) ₂ , Ba (hfac) ₂ , Ba (tmhd) ₂ (tmhd = 2, 2, 6, 6-tetramethyl-3, 5-heptanedione), Ba (TMHD) ₂ (tetraglyme), Ba (tmhd) ₂ ( pmdeta), Ba (tmhd) ₂ (tetraen), Ba (metmhd) ₂ , Ba (tmhd) ₂ (trine) _n , Ba (TMHD) ₂ L (L: lewis base), Ba (acac) ₂ L and the like. Can be.

A portion of the fifth reactant may be chemically adsorbed onto the STO thin film, and the remainder of the fifth reactant may be physically adsorbed onto or suspended in the chamber on the chemically adsorbed fifth reactant. .

After stopping the supply of the fifth reactant, the chamber is evacuated while supplying a purge gas into the chamber to remove the physically adsorbed fifth reactant and the fifth reactant suspended in the chamber. Accordingly, a barium precursor film may be formed on the STO thin film. As the purge gas, an inert gas such as nitrogen or argon may be used.

The sixth reactant including the strontium precursor is supplied onto the substrate on which the barium precursor film is formed to form a strontium precursor film on the barium precursor film. The sixth reactant includes a gaseous strontium precursor and may be carried by an inert gas such as argon or nitrogen. In addition, the liquid sixth reactant may be provided through a liquid delivery system and a vaporization system.

Examples of the strontium precursor include Sr (C ₅ ⁱ Pr ₃ H ₂ ) ₂ , SrS, Sr (thd) ₂ (thd = 2, 2, 6, 6-tetramethyl-3, 5-heptanedione), Sr (acac) ₂ , Sr (hfac) ₂ , Sr (tfac) ₂ , Sr (TMFD) ₂ , [Sr (TMHD) ₂ ] L (L: lewis base), Sr (tmhd) ₂ (tetraglyme), Sr (tmhd) ₂ (pmdeta ), [Sr (acac) ₂ ] L (L: lewis base), Sr (dmp) ₂ , Sr (metmhd) ₂ , Sr (tmhd) ₂ (trine) n and the like.

A portion of the sixth reactant may be chemically adsorbed onto the barium precursor film and the remainder of the sixth reactant may be physically adsorbed onto or suspended in the chamber on the chemically adsorbed sixth reactant. have.

After the supply of the sixth reactant is stopped, the chamber is evacuated while supplying a purge gas into the chamber, thereby removing the physically adsorbed sixth reactant and the sixth reactant suspended in the chamber. Accordingly, a strontium precursor film may be formed on the barium precursor film. As the purge gas, an inert gas such as nitrogen or argon may be used.

According to another embodiment of the present invention, a mixed reactant (or cocktail source) comprising a barium precursor and a strontium precursor may be used. That is, the mixed reactant may be provided on the STO thin film to form a barium strontium precursor film.

Subsequently, a seventh reactant including a titanium precursor is supplied onto the substrate 100 on which the barium precursor film and the strontium precursor film are formed to form a titanium precursor film on the strontium precursor film.

The seventh reactant may comprise a gaseous titanium precursor and may be carried by an inert gas such as nitrogen or argon. The vapor phase titanium precursor gas may also be provided through a bubbling system or a liquid delivery system and a vaporization system.

Examples of the titanium precursor include Ti (O ⁱ Pr) ₄ , Ti (TMHD) ₂ (O ⁱ Pr) ₂ , Ti (acac) ₄ , Ti (thac) ₂ (O ⁱ Pr) ₂ , Ti (hfac) ₂ ( O ⁱ Pr) ₂ , Ti (TMHD) ₂ (O ⁿ Bu) ₂ , Ti (acac) ₂ (O ⁿ Bu) ₂ , Ti (tfac) ₂ (O ⁿ Bu) ₂ , Ti (hfac) ₂ (O ⁿ Bu) ₂ , Ti (TMHD) ₂ (NMe ₂ ) ₂ , Ti (TMHD) ₂ (dmae), Ti (Nme ₂ ) ₄ , Ti (NEt ₂ ) ₄ , Ti (dmea) ₄ , Ti (dmea) ₂ ( ⁱ PrO) ₂ , Ti (hfac) ₂ (nBuO) ₂ , Ti (tfac) ₂ (nBuO) ₂ , Ti (acac) ₂ (nBuO) ₂ , Ti (TMHD) ₂ (nBuO) ₂ , Ti (TMHD) ₂ (iPrO) ₂ , Ti (hfac) ₂ ( ⁱ PrO) ₂ , Ti (tfac) ₂ ( ⁱ PrO) ₂ , Ti (acac) ₂ ( ⁱ PrO) ₂ , Ti (tmhd) ₂ (mpd), and the like. have.

A portion of the seventh reactant may be chemically adsorbed onto the strontium precursor membrane and the remainder of the seventh reactant may be physically adsorbed onto or suspended in the chamber on the chemically adsorbed seventh reactant. have.

After the supply of the seventh reactant is stopped, the chamber is evacuated while supplying a purge gas into the chamber to remove the physically adsorbed seventh reactant and the seventh reactant suspended in the chamber. Accordingly, a titanium precursor film may be formed on the strontium precursor film. As the purge gas, an inert gas such as nitrogen or argon may be used.

The fifth cycle of supplying the fifth reactant and the purge gas to form the barium precursor film and the sixth cycle of supplying the sixth reactant and the purge gas to form the strontium precursor film and the titanium precursor film to form the titanium precursor film The ratio between the seventh reactant and the seventh cycle of supplying the purge gas may be adjusted such that the concentration ratio of barium, strontium and titanium is about 1: 1: 1.

Subsequently, an oxidant is supplied onto the substrate 100 on which the barium precursor film, the strontium precursor film, and the titanium precursor film are formed, thereby forming a BST thin film (barium strontium) by an oxidation reaction between the barium precursor film, the strontium precursor film, the titanium precursor film, and the oxidant. Titanium oxide film). In particular, since the BST thin film is formed using atomic layer deposition on the crystallized STO thin film, it may be crystallized according to the crystal structure of the STO thin film during the steps. Therefore, a separate heat treatment for crystallizing the BST thin film is not required.

Subsequently, a purge gas for removing the reaction by-products and residual oxidant by the oxidation reaction is provided, and the reaction by-products and residual oxidant may be evacuated together with the purge gas. Meanwhile, oxygen (O ₂ ), ozone (O ₃ ), oxygen plasma, or the like may be used as the oxidant.

The steps for forming the BST thin film as described above may be repeatedly performed until a desired thickness, for example, a thickness of about 145 to 250 mm 3 is realized.

According to another embodiment of the present invention, the BST thin film may be formed through the following steps.

First, a barium precursor film is formed on a substrate using a fifth reactant including a barium precursor. Further details of the method of forming the barium precursor film are omitted since they are substantially the same as described above.

An oxidant is supplied onto the barium precursor film to form a barium oxide film on the STO thin film.

A strontium precursor film is formed on the substrate on which the barium precursor is formed by using the sixth reactant including the strontium precursor. Further details of the method of forming the strontium precursor film are substantially the same as described above, and thus will be omitted.

An oxidant is supplied onto the strontium precursor film to form a strontium oxide film on the barium oxide film.

A titanium precursor film is formed on the strontium oxide film using a seventh reactant including a titanium precursor. Further details of the method of forming the titanium precursor film are omitted since they are substantially the same as described above.

An oxidant is supplied onto the titanium precursor film to form a BST thin film by an oxidation reaction between the barium oxide film, the strontium oxide film, the titanium precursor film, and the oxidant. Since the BST thin film is formed by atomic layer deposition on the crystallized STO thin film, the BST thin film may have the same crystal structure as the STO thin film. Therefore, a separate heat treatment for crystallizing the BST thin film is not required.

According to another embodiment of the present invention, the BST thin film may be formed through the following steps.

First, a barium strontium precursor film is formed on the substrate 100 by using a mixed reactant including a barium precursor and a strontium precursor. Further details of the method of forming the barium strontium precursor film are similar to those described above and thus will be omitted.

An oxidant is supplied onto the barium strontium precursor film to form a barium strontium oxide film on the STO thin film.

A titanium precursor film is formed on the barium strontium oxide film using a seventh reactant including a titanium precursor. Further details of the method of forming the titanium precursor film are omitted since they are substantially the same as described above.

An oxidant is supplied onto the titanium precursor film to form a BST thin film by an oxidation reaction between the barium strontium oxide film, the titanium precursor film, and the oxidant. Since the BST thin film is formed by atomic layer deposition on the crystallized STO thin film, the BST thin film may have the same crystal structure as the STO thin film. Therefore, a separate heat treatment for crystallizing the BST thin film is not required.

Meanwhile, according to an embodiment of the present invention, the seed dielectric layer 130 and the bulk dielectric layer 131 may be formed in-situ in the same process chamber. In detail, the temperature of the substrate 100 may be maintained at about 300 to about 400 ° C. while forming the bulk dielectric layer 131. When the temperature of the substrate is higher than 400 ° C., it is not easy to control the thickness of the bulk dielectric layer 131, and thus, the step coverage of the bulk dielectric layer 131 may be poor. In addition, it is not easy to control the composition ratio between the components in the bulk dielectric layer 131. In particular, it is difficult to adjust the composition ratio for each position on the lower electrode 128 of the three-dimensional structure.

Referring to FIG. 5, the upper electrode 132 of the capacitor C is formed on the bulk dielectric layer 131 to form the lower electrode 128, the seed dielectric layer 130, the bulk dielectric layer 131, and the upper electrode 132. To form a capacitor (C) comprising a). In this case, the upper electrode 132 may be a semiconductor material such as polysilicon, a rare metal such as ruthenium (Ru), platinum (Pt) or iridium (Ir), or an alloy thereof, titanium nitride (TiN), or tantalum nitride (TaN). And conductive metal nitride such as tungsten nitride (WN) or the like. The upper electrode 132 may have a single layer or a multilayer structure.

As shown, although the lower electrode 128 has a cylindrical shape, embodiments of the present invention may be applied to the lower electrode having a three-dimensional structure of various shapes.

X-ray Diffraction Analysis on Bulk Dielectric Films

6 is a graph showing the results of X-ray diffraction analysis of a composite dielectric film formed according to an embodiment of the present invention and a dielectric film formed according to the related art.

First, an STO thin film and a BTO thin film were formed according to an embodiment of the present invention. Specifically, the STO thin film was formed on the substrate to about 50 kPa by atomic layer deposition using Sr (metmhd) and Ti (tmhd) ₂ (mpd). At this time, the substrate was heated to a temperature of about 350 ℃, the pressure inside the atomic layer deposition chamber in which the substrate is located was maintained about 1 torr.

Subsequently, the first BTO thin film was formed to a thickness of about 150 kPa through atomic layer deposition using Ba (metmhd) and Ti (tmhd) ₂ (mpd) on the STO thin film in the same chamber. At this time, the temperature of the substrate was maintained about 350 ℃, the pressure inside the chamber was maintained about 1 torr.

In addition, according to the prior art, a second BTO thin film was formed on the substrate using a thickness of about 200 kPa using Ba (metmhd) and Ti (tmhd) ₂ (mpd). At this time, the temperature of the substrate was maintained about 350 ℃, the pressure inside the chamber was maintained about 1 torr.

Referring to FIG. 6, in the composite dielectric film including the STO thin film and the first BTO thin film, it was confirmed that the first BTO thin film was crystallized, but crystallization was not confirmed in the second BTO thin film.

According to the embodiments of the present invention as described above, the BTO thin film or BST thin film can be crystallized in the deposition step by forming the BTO thin film or BST thin film on the STO thin film crystallized by atomic layer deposition through atomic layer deposition. have. Therefore, the heat treatment for crystallization of the STO thin film and the heat treatment for crystallization of the BTO thin film or BST thin film can be omitted. Therefore, the manufacturing process of the semiconductor device can be simplified, and the thermal stress of the semiconductor device can be reduced.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (13)

Forming a lower electrode on the substrate; Forming a perovskite seed dielectric layer crystallized using atomic layer deposition on the lower electrode; Forming a crystallized perovskite bulk dielectric layer using atomic layer deposition on the seed dielectric layer; And Forming an upper electrode on the bulk dielectric layer. The method of claim 1, wherein the oxide dielectric layer capacitor manufacturing method comprising the strontium titanium oxide (SrTiO _3), or calcium titanium oxide (CaTiO _3). The method of claim 2, wherein the forming of the seed dielectric layer comprises: Supplying a first reactant including a strontium precursor on the lower electrode to form a strontium precursor film on the lower electrode; Supplying a second reactant including a titanium precursor on the strontium precursor film to form a titanium precursor film; And Supplying an oxidant on the titanium precursor film to form a crystallized strontium titanium oxide film. The method of claim 2, wherein the forming of the seed dielectric layer comprises: Supplying a first reactant including a strontium precursor on the lower electrode to form a strontium precursor film on the lower electrode; Supplying an oxidant on the strontium precursor film to form a strontium oxide film; Supplying a second reactant including a titanium precursor onto the strontium oxide film to form a titanium precursor film; And Supplying an oxidant on the titanium precursor film to form a crystallized strontium titanium oxide film. The method of claim 1, wherein the bulk dielectric is barium titanium oxide (BaTiO _3), barium strontium titanium oxide _{((Ba, Sr) TiO 3} ), strontium titanium oxide (SrTiO _3), calcium titanium oxide (CaTiO _3), barium strontium Zirconium titanium oxide ((Ba, Sr) (Zr, Ti) O ₃ ) and barium zirconium oxide (BaZrO ₃ ) at least one selected from the group consisting of a capacitor manufacturing method. The method of claim 5, wherein the forming of the bulk dielectric layer comprises: Supplying a first reactant including a barium precursor on the seed dielectric layer to form a barium precursor layer on the seed dielectric layer; Supplying a second reactant including a titanium precursor onto the barium precursor film to form a titanium precursor film; And Supplying an oxidant on the titanium precursor film to form a crystallized barium titanium oxide film. The method of claim 5, wherein the forming of the bulk dielectric layer comprises: Supplying a first reactant including a barium precursor on the seed dielectric layer to form a barium precursor layer on the seed dielectric layer; Supplying an oxidant on the barium precursor film to form a barium oxide film; Supplying a second reactant including a titanium precursor on the barium oxide film to form a titanium precursor film; And Supplying an oxidant on the titanium precursor film to form a crystallized barium titanium oxide film. The method of claim 5, wherein the forming of the bulk dielectric layer comprises: Supplying a first reactant including a barium precursor on the seed dielectric layer to form a barium precursor layer on the seed dielectric layer; Supplying a second reactant including a strontium precursor on the barium precursor film to form a strontium precursor film on the barium precursor film; Supplying a third reactant including a titanium precursor to the strontium precursor film to form a titanium precursor film; And Supplying an oxidant on said titanium precursor film to form a crystallized barium strontium titanium oxide film. The method of claim 5, wherein the forming of the bulk dielectric layer comprises: Supplying a first reactant including a barium precursor on the seed dielectric layer to form a barium precursor layer on the seed dielectric layer; Supplying an oxidant on the barium precursor film to form a barium oxide film; Supplying a second reactant including a strontium precursor on the barium oxide film to form a strontium precursor film on the barium oxide film; Supplying an oxidant on the strontium precursor film to form a strontium oxide film; Supplying a third reactant including a titanium precursor to the strontium oxide film to form a titanium precursor film; And Supplying an oxidant on said titanium precursor film to form a crystallized barium strontium titanium oxide film. The method of claim 5, wherein the forming of the bulk dielectric layer comprises: Supplying a first reactant including a barium precursor and a strontium precursor on the seed dielectric layer to form a barium strontium precursor layer on the seed dielectric layer; Supplying a second reactant including a titanium precursor onto the barium strontium precursor film to form a titanium precursor film; And Supplying an oxidant on said titanium precursor film to form a crystallized barium strontium titanium oxide film. The method of claim 5, wherein the forming of the bulk dielectric layer comprises: Supplying a first reactant including a barium precursor and a strontium precursor on the seed dielectric layer to form a barium strontium precursor layer on the seed dielectric layer; Supplying an oxidant on the barium strontium precursor film to form a barium strontium oxide film; Supplying a second reactant including a titanium precursor on the barium strontium oxide film to form a titanium precursor film; And Supplying an oxidant on said titanium precursor film to form a crystallized barium strontium titanium oxide film. The method of claim 1, wherein the seed dielectric layer and the bulk dielectric layer are formed at 300 to 400 ° C. 3. The method of claim 1, wherein forming the seed dielectric layer and forming the bulk dielectric layer are formed in-situ in a process chamber.

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