JP2019031477A - Ge-CONTAINING Co FILM FORMING MATERIAL, Ge-CONTAINING Co FILM, AND FILM DEPOSITION METHOD THEREFOR - Google Patents

Abstract

To provide a film forming material and a film deposition process for forming a Ge-containing Co film containing a desired amount of Ge at a lower temperature.SOLUTION: There is provided a film deposition material having one of following formulae: RRRGe-Co(CO), where R, Rand Rare each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated nonaromatic hydrocarbon group, in which the non-aromatic hydrocarbon group excludes a crosslinked non-aromatic hydrocarbon group, and the halogenated nonaromatic hydrocarbon group excludes a crosslinked halogenated nonaromatic hydrocarbon group. Co(CO)RRGe-Co(CO), where Rand Rare each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated nonaromatic hydrocarbon group, in which the non-aromatic hydrocarbon group excludes a crosslinked non-aromatic hydrocarbon group, and the halogenated nonaromatic hydrocarbon group excludes a crosslinked halogenated nonaromatic hydrocarbon group.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a Ge-containing Co film forming material, a Ge-containing Co film, and a method for forming a Ge-containing Co film using the Ge-containing Co film forming material.

  Metal silicide films are widely used as contact materials, gate electrodes, wiring materials, or diffusion barrier layers in the microelectronics field due to their low resistance, thermal stability, and high compatibility with other materials. ing.

  However, as a next-generation channel material, Ge, which has high mobility, is expected instead of Si, which is currently widely used. When Ge is used for the channel material, a metal germanide film (for example, cobalt germanide film) is used as a contact material instead of a conventionally used metal silicide film (for example, cobalt silicide film). is expected.

  On the other hand, in the wiring process, a Si-containing cobalt film is generally used as a diffusion prevention barrier layer for copper wiring. On the other hand, Ge-containing Co films are attracting attention as next-generation diffusion barrier layers because of their high adhesion. As a method for forming a Ge-containing Co film, after forming a Co film and a Ge film, or after forming a Co film on a Ge substrate, annealing is performed to obtain a Ge-containing Co film. The method is known (for example, refer nonpatent literature 1). In addition, a method of obtaining a Ge-containing Co film by a CVD method or an ALD method using a precursor containing Co and Ge is also disclosed (for example, see Patent Document 1).

International Publication No. 2016/172792 JP-T-2006-513086

Materials Chemistry and Physics 134 (2012) 153-157, The composition, structure and optical properties of weakly magnetic Co-containing amorphous Si and Ge films, F.A. Ferri, M.A.Pereira-da-Silvaa, G. A. Domrachev and four others, “THERMAL DECOMPOSITION OF TETRACARBONYL (TRIETHYLGERMYL) COBALT”, Izvestia Akademii Nauk SSSR, Seria Khimicheka, May 8th, 19th. 12, p. 2804-2806 D. J. et al. Patmore, et al., “Organometallic Compounds with Metal-Metal Bonds. VII”, Inorganic Chemistry, May 1967, Vol. 6, no. 5, p. 981-988 ROBERT F.R. GERLACH, two others, "TRNSITION METALCARBONYL DERIVATES OF THE GERMANES PART XI", Journal of Organometallic Chemistry, 1979, 182, p. 285-298 David J.M. Brauer, et al., “Preparation and Properties of Ge (CF3) 3 Products of Transition-Metal Carbonyls”, Organometallics, 1983, Vol. 2, no. 2, p. 263-267

  In the method of obtaining a Ge-containing Co film by annealing, the semiconductor film is greatly damaged due to the annealing being performed at a high temperature. On the other hand, when a Ge-containing Co film is formed by a CVD method or an ALD method using a precursor containing Co and Ge, the resistance value increases, and the stoichiometric ratio of Co and Ge is increased. There are problems that it is difficult to control and the amount of impurities in the film increases.

When a precursor containing Co and Si (for example, Et ₃ Si—Co (CO) ₄ ) is used to form a film at a low temperature of about 200 ° C., a Co film is obtained, and the Si content in the Co film There were very few (patent document 1 and patent document 2). From this result, it is expected that a Co film can be obtained even when a similar precursor containing Co and Ge is used, and it is difficult to obtain a Co film containing a desired amount of Ge. Conceivable.

  Examples of the compound containing Co and Ge include a CoGe compound containing an alkyl group (Non-Patent Document 2) and a CoGe compound containing a halogeno group (Non-Patent Document 3, Non-Patent Document 4 and Non-Patent Document 5). Are known. However, an example in which these compounds are applied to the formation of a Ge-containing Co film is not known.

  From the above, a film forming process for forming a Ge-containing Co film containing a desired amount of Ge at a low temperature is desired.

  Notation and nomenclature, some abbreviations, symbols and terms are used throughout the following specification and claims.

  As used herein, the term “alkyl group” refers to a saturated or unsaturated functional group containing only carbon and hydrogen atoms. Furthermore, the term “alkyl group” refers to a linear, branched or cyclic alkyl group. Examples of straight chain alkyl groups include, but are not limited to, methyl, ethyl, propyl, butyl and the like. An example of a branched alkyl group includes, but is not limited to, t-butyl. Examples of the cyclic alkyl group include, but are not limited to, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, and the like. Examples of the bridging alkyl group include, but are not limited to, a vinyl group coordinated to a single metal atom.

As used herein, the abbreviation “Me” refers to a methyl group, the abbreviation “Et” refers to an ethyl group, the abbreviation “Pr” refers to any propyl group (ie, normal propyl or isopropyl), and the abbreviation “ ^I Pr” refers to an isopropyl group, the abbreviation “Bu” refers to any butyl group (normal butyl, isobutyl, tertiary butyl, secondary butyl), the abbreviation “ ^t Bu” refers to a tertiary butyl group, and the abbreviation “ “ ^s Bu” refers to a secondary butyl group and the abbreviation “ ⁱ Bu” refers to an isobutyl group.

  Common abbreviations for elements from the Periodic Table of Elements are used herein. Elements may be referred to by these abbreviations (eg, Co refers to cobalt, Si refers to silicon, Ge refers to germanium, C refers to carbon, etc.).

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the Ge-containing Co film forming material according to the present invention is:
A material for forming a Ge-containing Co film for manufacturing a semiconductor device,
It is a compound represented by the following general formula (1) or the following general formula (2).
R ¹ R ² R ³ Ge—Co (CO) ₄ (1)
(In the general formula (1), R ¹ , R ² and R ³ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group. Non-aromatic hydrocarbon groups exclude cross-linked non-aromatic hydrocarbon groups, and halogenated non-aromatic hydrocarbon groups exclude cross-linked halogenated non-aromatic hydrocarbon groups.)
Co (CO) ₄ R ⁴ R ⁵ Ge—Co (CO) ₄ (2)
(In the general formula (2), R ⁴ and R ⁵ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group, or a halogenated non-aromatic hydrocarbon group. (The hydrocarbon group excludes a crosslinked non-aromatic hydrocarbon group, and the halogenated non-aromatic hydrocarbon group excludes a crosslinked halogenated non-aromatic hydrocarbon group.)

  According to the Ge-containing Co film forming material of this application example, the Ge-containing Co film containing a desired amount of Ge can be formed on the substrate in the chamber. Since hydrogen bonded to Ge, non-aromatic hydrocarbon group, halogeno group or halogenated non-aromatic hydrocarbon group does not have π electrons and does not have a crosslinked structure, the degree of freedom of rotation of the bond is high. It is easily detached from Ge and removed out of the chamber. Therefore, carbon-based impurities derived from hydrogen, non-aromatic hydrocarbon groups, halogeno groups or halogenated non-aromatic hydrocarbon groups bonded to Ge remain in the Ge-containing Co film formed on the substrate in the chamber. Hard to do. In addition, since non-aromatic hydrocarbon groups and halogenated non-aromatic hydrocarbon groups are eliminated at a relatively low temperature, film formation can be performed at a low temperature of 350 ° C. or lower, for example. From the above, a Ge-containing Co film containing a small amount of carbon-based impurities and containing a desired amount of Ge can be obtained at a low temperature of 350 ° C. or less, for example, without performing annealing.

[Application Example 2]
In applications 1 Ge-containing Co film forming material, the compound represented by the general formula (1) or the general formula (2) ^{_{is, NMe 3, NEt 3, N}} i Pr 3, NMeEt 2, NC 5 H 5 , OC ₄ H ₈ , Me ₂ O, Et ₂ O, Et ₂ S, ⁿ Pr ₂ S and ⁿ Bu ₂ S can further comprise one or two neutral adduct ligands .

  According to this application example, the fluidity of the compound represented by the general formula (1) or the general formula (2) can be increased, and introduction into the chamber can be further facilitated. For example, when the Ge-containing Co film forming material is solid, it can be liquefied by including the neutral adduct ligand. By liquefying, the Ge-containing Co film-forming material can be pumped with a carrier gas or fed with a liquid feed pump. This not only facilitates introduction into the chamber, but also facilitates work when filling the container with the Ge-containing Co film-forming material, and makes it possible to reduce contamination by impurities. Although a method of dissolving in a solvent is also conceivable as a method of liquefaction, according to this application example including a neutral adduct ligand, it becomes possible to handle a Ge-containing Co film forming material at a higher concentration.

[Application Example 3]
The Ge-containing Co film forming material of Application Example 1 or Application Example 2 is a compound represented by the general formula (1), and R ¹ , R ^2, and R ³ each independently have 1 to 4 carbon atoms. The following hydrocarbon groups or halogenated hydrocarbon groups can be used.

  The Ge-containing Co film forming material of this application example has a suitable vapor pressure, and the Ge-containing Co film can be formed at a suitable film formation speed. In addition, the Ge-containing Co film forming material of this application example is easy to handle because it has excellent thermal stability and / or chemical stability.

[Application Example 4]
In the Ge-containing Co film forming material of Application Example 3,
The compound represented by the general formula (1) may be Et ₃ Ge—Co (CO) ₄ .

According to such an application example, Et ₃ Ge—Co (CO) _{4, which} is a Ge-containing Co film forming material, is a liquid at room temperature, so that it can be easily supplied to the chamber. Furthermore, the ethyl group bonded to Ge is particularly easily detached to form gaseous ethylene. For this reason, it is difficult for carbon-based impurities derived from ethyl groups to remain on the Ge-containing Co film, and it becomes possible to obtain a particularly high-purity Ge-containing Co film.

[Application Example 5]
The Ge-containing Co film forming material of Application Example 1 or Application Example 2 is a compound represented by the general formula (2), and R ⁴ and R ⁵ are each independently carbonized having 1 to 4 carbon atoms. It can be a hydrogen group or a halogenated hydrocarbon group.

  According to this application example, the Ge-containing Co film forming material has a suitable vapor pressure, and the Ge-containing Co film can be deposited at a suitable deposition rate. In addition, according to this application example, the Ge-containing Co film forming material has excellent thermal stability and / or chemical stability, and thus is easy to handle. Further, since Ge and Co, which are atoms forming the Ge-containing Co film, exist in a single molecule (one Ge and two Co), a higher deposition rate can be obtained.

[Application Example 6]
In the Ge-containing Co film forming material of Application Example 5,
The compound represented by the general formula (2) may be Co (CO) ₄ Et ₂ Ge—Co (CO) ₄ .

According to this application example, in the molecule of Co (CO) ₄ Et ₂ Ge—Co (CO) ₄ , which is a Ge-containing Co film forming material, the ethyl group bonded to Ge is particularly easily desorbed to form a gaseous state. Form ethylene. For this reason, it is difficult for carbon-based impurities derived from ethyl groups to remain on the Ge-containing Co film, and it becomes possible to obtain a particularly high-purity Ge-containing Co film.

[Application Example 7]
One aspect of the Ge-containing Co film according to the present invention is a Ge-containing Co film formed by depositing the Ge-containing Co film forming material of any one of Application Examples 1 to 6 by a CVD method or an ALD method. It is a membrane.

[Application Example 8]
The Ge-containing Co film of Application Example 7 may have a Ge: Co composition ratio of Ge: Co = 1: 99 to 99: 1.

  The composition ratio of Ge and Co can be arbitrarily changed depending on the characteristics of the functional group bonded to the Ge atom, the temperature at the time of film formation, and the like.

[Application Example 9]
The Ge-containing Co film of Application Example 7 or Application Example 8 may have a thickness of 0.1 nm to 400 nm.

  According to this application example, a Ge-containing Co film having a film thickness of 0.1 nm or more and 400 nm or less can be formed in the recess of the substrate to form a barrier layer. The film thickness of the Ge-containing Co film as the barrier layer can be more preferably 0.1 nm or more and 30 nm or less, and particularly preferably 0.1 nm or more and 10 nm or less.

  Further, a Ge-containing Co film having a film thickness of 0.1 nm or more and 400 nm or less can be formed on a flat portion on the substrate to form a contact layer. The film thickness of the Ge-containing Co film as the contact layer can be more preferably 0.1 nm or more and 50 nm or less, and particularly preferably 0.1 nm or more and 20 nm or less.

[Application Example 10]
The Ge-containing Co film of any one of Application Examples 7 to 9 has a bulk resistance value of preferably 6 μΩ · cm to 300 μΩ · cm, more preferably 10 μΩ · cm to 250 μΩ · cm. In particular, it can be 10 μΩ · cm or more and 60 μΩ · cm or less.

  Since the Ge-containing Co film of this application example has a low bulk resistance value, it is particularly suitable as a barrier layer and / or a contact layer for which a low bulk resistance value is required.

[Application Example 11]
The Ge-containing Co film of any one of Application Examples 7 to 10 may have a surface roughness (RMS) of 0.01 nm or more and 15 nm or less.

  The Ge-containing Co film of this application example has a flat film surface and is suitable as a barrier layer and / or a contact layer.

[Application Example 12]
When the Ge-containing Co film of any one of Application Examples 7 to 11 is formed on a substrate having at least one recess, the inner wall surface of the recess or the film thickness of the surface of the substrate The thickness ratio of the inner bottom surface can be 0.2 or more and 1.1 or less.

One of the indexes for evaluating the uniformity of the deposited film is step coverage. The concept of step coverage in this specification will be described with reference to FIG. FIG. 1 schematically shows a cross section in which a Ge-containing Co film 20 is formed in a substrate 10 and a recess 12 formed in the substrate 10. “Step coverage” refers to the thickness of the Ge-containing Co film formed on the surface of the substrate (x in FIG. 1) for the film formed in the substrate and the recess formed in the substrate. The film thickness of the Ge-containing Co film formed on the inner wall surface of the recess (y in FIG. 1) and / or the film thickness of the Ge-containing Co film formed on the inner bottom surface of the recess (in FIG. Assess by comparing z). The film thickness of the inner wall surface of the recess is obtained by measuring the film thickness of the inner wall surface at a height (1/2 Dep) that is ½ of the depth of the recess (denoted as Dep).
The ratio of the film thickness of the Ge-containing Co film formed inside the recess to the film thickness of the Ge-containing Co film formed on the surface of the substrate is preferably 0.2 or more and 1.1 or less. More preferably, it can be 0.5 or more and 1.1 or less, and particularly preferably 0.9 or more and 1.1 or less.

[Application Example 13]
The Ge-containing Co film of any one of Application Examples 7 to 12 may have a minimum continuous film thickness of 1 nm or more and 5 nm or less.

The “minimum continuous film thickness” in this specification is the resistance value (hereinafter referred to as “R”) of the film to be measured with respect to the film thickness of the film to be measured (hereinafter referred to as “d”). A value (R × d ³ ) obtained by multiplying the cube of the film thickness (d) is plotted, and the film thickness at which the value of R × d ³ is minimized.

  According to such an application example, the obtained Ge-containing Co film has few pinholes, and a device having good electrical characteristics can be obtained.

[Application Example 14]
The Ge-containing Co film of any one of the application examples 7 to 13 may be a low resistance contact layer formed in the source / drain region of the FinFET transistor disposed on the Si or Ge substrate.

[Application Example 15]
The Ge-containing Co film according to any one of Application Examples 7 to 13 can be a barrier layer of a wiring layer.

[Application Example 16]
One aspect of the semiconductor device according to the present invention is a semiconductor device including the Ge-containing Co film of Application Examples 7 to 15.

[Application Example 17]
One embodiment of an electronic device according to the present invention is an electronic device including the semiconductor device of Application Example 16.

  The electronic device is not particularly limited, and can be, for example, an LCD-TFT device, a photovoltaic device, a flat panel display, an organic solar cell, an organic EL element, an organic thin film transistor, an organic light emitting sensor, or the like.

[Application Example 18]
One aspect of the method for forming a Ge-containing Co film according to the present invention is as follows.
A first step of introducing a substrate into the chamber;
A Ge-containing Co film forming material represented by the following general formula (1) or the following general formula (2) is introduced into a chamber in which the substrate is disposed while controlling the amount of the Ge-containing Co film forming material introduced. Two processes,
A third step of depositing at least a part of the Ge-containing Co film forming material on the substrate so as to form the Ge-containing Co film;
including.
R ¹ R ² R ³ Ge—Co (CO) ₄ (1)
(In the general formula (1), R ¹ , R ² and R ³ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group. Non-aromatic hydrocarbon groups exclude cross-linked non-aromatic hydrocarbon groups, and halogenated non-aromatic hydrocarbon groups exclude cross-linked halogenated non-aromatic hydrocarbon groups.)
Co (CO) ₄ R ⁵ R ⁶ Ge—Co (CO) ₄ (2)
(In the general formula (2), R ⁵ and R ⁶ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group, or a halogenated non-aromatic hydrocarbon group. (The hydrocarbon group excludes a crosslinked non-aromatic hydrocarbon group, and the halogenated non-aromatic hydrocarbon group excludes a crosslinked halogenated non-aromatic hydrocarbon group.)

  According to this application example, a Ge-containing Co film containing a desired amount of Ge can be formed on the substrate.

[Application Example 19]
In the method for forming the Ge-containing Co film of Application Example 18,
The third step includes chemical vapor deposition (CVD), atomic layer deposition (ALD), plasma enhanced chemical vapor deposition (PECVD), plasma enhanced atomic layer deposition (PEALD), pulsed chemical vapor deposition (PCVD), low pressure chemical vapor deposition ( LPCVD), low pressure chemical vapor deposition (SACVD), atmospheric pressure chemical vapor deposition (APCVD), spatial ALD, radical assisted deposition, supercritical fluid deposition, and combinations thereof.

[Application Example 20]
In the method of forming the Ge-containing Co film of Application Example 18 or Application Example 19,
And a fourth step of introducing into the chamber an additive gas selected from the group consisting of ammonia, hydrogen, inert gas, alcohol, amino alcohol, amine, GeH ₄ , Ge ₂ H ₆ and combinations thereof. Can do.

  The inert gas may be any gas that does not react in the chamber with the Ge-containing Co film forming material represented by the general formula (1) or the general formula (2), such as argon, helium, nitrogen, and the like. A gas selected from the group consisting of: An amino alcohol is not specifically limited, For example, ethanolamine may be sufficient.

  According to this application example, it is possible to obtain Ge-containing Co films having different Ge: Co ratios by changing the additive gas. In addition, the film formation temperature can be lowered by introducing the additive gas.

[Application Example 21]
In the method for forming a Ge-containing Co film according to any one of Application Example 18 to Application Example 20,
The third step may be performed at a temperature of 0 ° C. or higher and 350 ° C. or lower, preferably 100 ° C. or higher and 250 ° C. or lower, particularly preferably 160 ° C. or higher and 200 ° C. or lower. Can be done at. The temperature at which the third step is performed is a temperature measured in the chamber (for example, the temperature of the substrate holder or the temperature of the inner wall of the chamber).

According to this application example, it is possible to obtain a substantially uniform Ge-containing Co film having a desired Ge and Co stoichiometric ratio at a suitable deposition rate. Specifically, when Et ₃ Ge—Co (CO) ₄ is used as a Ge-containing Co film forming material, a Co-rich Ge-containing Co film is formed when the film is formed at a lower temperature (for example, 0 ° C. to 200 ° C.). When a film is formed at a higher temperature (for example, 300 ° C. to 350 ° C.), a Ge-rich Ge-containing Co film can be obtained. This indicates that the stoichiometric ratio of Ge and Co in the deposited film can be controlled by the deposition temperature.

[Application Example 22]
In the method for forming a Ge-containing Co film according to any one of Application Example 18 to Application Example 21,
The pressure in the chamber may be 0.06 Torr or more and atmospheric pressure or less, more preferably 0.1 Torr or more and 30 Torr or less, and particularly preferably 1 Torr or more and 15 Torr or less.

  According to the Ge-containing Co film forming material according to the present invention, a Ge-containing Co film can be obtained at a low temperature without performing the annealing step. Further, according to the method for forming a Ge-containing Co film according to the present invention, the Ge-containing Co film can be formed at a low temperature by using the Ge-containing Co film forming material.

It is the schematic which shows the step coverage measurement location used by this embodiment. It is a schematic block diagram of the apparatus used suitably by this embodiment. It is a figure which shows the flow of CVD method which concerns on this embodiment. 2 is a thermal analysis result of Et ₃ Ge—Co (CO) ₄ in Example 1. FIG. 2 is a mass spectrum analysis result of Et ₃ Ge—Co (CO) ₄ in Example 1. FIG. 2 is a ¹ H-NMR analysis result of Et ₃ Ge—Co (CO) ₄ in Example 1. FIG. _{3 is} a ¹³ C-NMR analysis result of Et ₃ Ge—Co (CO) ₄ in Example 1. FIG. It is _Et 3 Ge-Co _(CO) vapor pressure measurements of ₄ in Example 1. FIG. 3 is a measurement result of temperature and pressure characteristics of Et ₃ Ge—Co (CO) ₄ in Example 1. FIG. 2 is a measurement result of thermal stability of Et ₃ Ge—Co (CO) ₄ in Example 1. FIG. 10 is an XPS analysis result of a Ge-containing Co film in Example 2. 6 is a SEM analysis result of a Ge-containing Co film in Example 2. 6 is a SEM analysis result of a Ge-containing Co film in Example 2. A _{Et 2 Ge- (Co (CO)} 4) 2 of the thermal analysis results in Example 25. A _{Et 2 Ge- (Co (CO)} 4) 1 H-NMR analysis results of ₂ in Example 25. It is a ¹³ C-NMR analysis result of Et ₂ Ge— (Co (CO) ₄ ) ₂ in Example 25. A _{Et 2 Ge- (Co (CO)} 4) 2 vapor pressure measurement results in Example 25. FIG. 20 is an XPS analysis result of a Ge-containing Co film in Example 26. FIG. 20 is a SEM analysis result of a Ge-containing Co film in Example 26. 20 is a SEM analysis result of a Ge-containing Co film in Example 26. 20 is an XPS analysis result of a Ge-containing Co film in Example 27. 20 is a SEM analysis result of a Ge-containing Co film in Example 27. 20 is a SEM analysis result of a Ge-containing Co film in Example 27. 20 is an XPS analysis result of a Ge-containing Co film in Example 28. 19 is a SEM analysis result of a Ge-containing Co film in Example 28. 19 is a SEM analysis result of a Ge-containing Co film in Example 28.

  Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited to only the embodiments described below, and includes various modifications that are implemented without departing from the scope of the present invention.

1. Ge-containing Co film forming material The Ge-containing Co film forming material according to the present embodiment is a material for forming a Ge-containing Co film for manufacturing a semiconductor device, and is represented by the following general formula (1) or the following general formula (2). It is a compound represented by this.
R ¹ R ² R ³ Ge—Co (CO) ₄ (1)
(In the general formula (1), R ¹ , R ² and R ³ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group. Non-aromatic hydrocarbon groups exclude cross-linked non-aromatic hydrocarbon groups, and halogenated non-aromatic hydrocarbon groups exclude cross-linked halogenated non-aromatic hydrocarbon groups.)
Co (CO) ₄ R ⁴ R ⁵ Ge—Co (CO) ₄ (2)
(In the general formula (2), R ⁴ and R ⁵ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group. (The hydrocarbon group excludes a crosslinked non-aromatic hydrocarbon group, and the halogenated non-aromatic hydrocarbon group excludes a crosslinked halogenated non-aromatic hydrocarbon group.)

Ge-containing Co film forming material represented by the general formula (1) or the general formula (2) ^{_{is, NMe 3, NEt 3, N}} i Pr 3, NMeEt 2, NC 5 H 5, OC 4 H 8, Me One or two neutral adduct ligands selected from the group consisting of ₂ O, Et ₂ O, Et ₂ S, ⁿ Pr ₂ S and ⁿ Bu ₂ S can be further included. More preferably, the neutral adduct ligand is NMe ₃ or NEt ₃ .

In one embodiment, the Ge-containing Co film forming material is a compound represented by the general formula (1), and in the general formula (1), R ¹ , R ^2, and R ³ are each independently hydrogen. A non-aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group.

As the compound represented by the general formula (1), R ¹ , R ² and R ³ are each independently a hydrocarbon group having 1 to 4 carbon atoms or halogenated carbonization having 1 to 4 carbon atoms. A hydrogen group is preferred. Examples of the hydrocarbon group having 1 to 4 carbon atoms include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, butyl group, isobutyl group, and t-butyl group. Examples of the halogenated hydrocarbon group having 1 to 4 carbon atoms include groups in which some or all of the hydrogen atoms of the above-exemplified alkyl groups are substituted with halogeno groups (—F, —Cl, —Br, —I). Can be mentioned.

Specific examples of such a Ge-containing Co film forming material include Me ₃ Ge—Co (CO) ₄ , Et ₃ Ge—Co (CO) ₄ , ⁱ Pr ₃ Ge—Co (CO) ₄ , and ⁿ Pr ₃ Ge. ^{_{-Co (CO) 4, n Bu}} 3 Ge-Co (CO) 4, i Bu 3 Ge-Co (CO) 4, t Bu 3 Ge-Co (CO) 4, Me 2 EtGe-Co (CO) 4, _{MeEt 2 Ge-Co (CO)} 4, Me 2 HGe-Co (CO) 4, Et 2 HGe-Co (CO) 4, i Pr 2 HGe-Co (CO) 4, n Pr 2 HGe-Co (CO) ^{_{4, n Bu 2 HGe-Co}} (CO) 4, i Bu 2 HGe-Co (CO) 4, t Bu 2 HGe-Co (CO) 4, MeEtHGe-Co (CO) 4, F 3 Ge-Co (CO ) _4, Cl _{3 e-Co (CO) 4,} Br 3 Ge-Co (CO) 4, I 3 Ge-Co (CO) 4, F 2 HGe-Co (CO) 4, Cl 2 HGe-Co (CO) 4, Br 2 _{HGe-Co (CO) 4,} I 2 HGe-Co (CO) 4, FH 2 Ge-Co (CO) 4, ClH 2 Ge-Co (CO) 4, BrH 2 Ge-Co (CO) 4, IH 2 Ge—Co (CO) ₄ , (CF ₃ ) ₃ Ge—Co (CO) ₄ , (CCl ₃ ) ₃ Ge—Co (CO) ₄ , (CBr ₃ ) ₃ Ge—Co (CO) ₄ , (CI ₃ ) ) ₃ Ge—Co (CO) ₄ , (C ₂ F ₅ ) ₃ Ge—Co (CO) ₄ , (HC ₂ F ₄ ) ₃ Ge—Co (CO) ₄ , (H ₂ C ₂ F ₃ ) ₃ Ge -Co _{(CO) 4,} or _{(H 3 C 2 F 2)} 3 Ge-Co (C ) ₄ and the like, but not limited thereto. Among _{these, Et 3 Ge-Co (CO} ) 4 is preferred.

In another embodiment, the Ge-containing Co film forming material is a compound represented by the general formula (2), and in the general formula (2), R ⁴ and R ⁵ are each independently hydrogen, non-aromatic. An aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group.

As the compound represented by the general formula (2), R ⁴ and R ⁵ are each independently a hydrocarbon group having 1 to 4 carbon atoms or a halogenated hydrocarbon group having 1 to 4 carbon atoms. Preferably there is. Examples of the hydrocarbon group having 1 to 4 carbon atoms include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, butyl group, isobutyl group, and t-butyl group. Examples of the halogenated hydrocarbon group having 1 to 4 carbon atoms include groups in which part or all of the hydrogen atoms of the above-exemplified alkyl groups are substituted with halogeno groups (—F, —Cl, —Br, —I). It is done.

Specific examples of such a Ge-containing Co film forming material include Co (CO) ₄ Me ₂ Ge—Co (CO) ₄ , Co (CO) ₄ Et ₂ Ge—Co (CO) ₄ , and Co (CO) _{4. ^{i Pr 2 Ge-Co (CO}} ) 4, Co (CO) 4 n Pr 2 Ge-Co (CO) 4, Co (CO) 4 n Bu 2 Ge-Co (CO) 4, Co (CO) 4 i Bu ₂ Ge—Co (CO) ₄ , Co (CO) ₄ ^t Bu ₂ Ge—Co (CO) ₄ , Co (CO) ₄ MeEtGe—Co (CO) ₄ , Co (CO) ₄ F ₂ Ge—Co (CO ) ₄ , Co (CO) ₄ Cl ₂ Ge—Co (CO) ₄ , Co (CO) ₄ Br ₂ Ge—Co (CO) ₄ , Co (CO) ₄ I ₂ Ge—Co (CO) ₄ , Co ( _{CO) 4 FHGe-Co (CO} ) 4, Co (CO) _{4 ClHGe-Co (CO) 4} , Co (CO) 4 BrHGe-Co (CO) 4, Co (CO) 4 IHGe-Co (CO) 4, Co (CO) 4 (CF 3) 2 Ge-Co (CO ) ₄ , Co (CO) ₄ (CCl ₃ ) ₂ Ge—Co (CO) ₄ , Co (CO) ₄ (CBr ₃ ) ₂ Ge—Co (CO) ₄ , Co (CO) ₄ (CI ₃ ) ₂ Ge _{-Co (CO) 4, Co (} CO) 4 (C 2 F 5) 2 Ge-Co (CO) 4, Co (CO) 4 (HC 2 F 4) 2 Ge-Co (CO) 4, Co (CO ) ₄ (H ₂ C ₂ F ₃ ) ₂ Ge—Co (CO) ₄ , or Co (CO) ₄ (H ₃ C ₂ F ₂ ) ₂ Ge—Co (CO) _4, etc. Not. Among these, Co (CO) ₄ Et ₂ Ge—Co (CO) ₄ is preferable.

<Synthesis of Ge-containing Co film forming material>
The Ge-containing Co film forming material represented by the general formula (1) is synthesized by adding a Ge compound represented by the following general formula (3) to a Co (CO) ₄ solution in an inert gas atmosphere. can do. Hydrogen evolution is observed during the reaction. Examples of the inert gas atmosphere include, but are not limited to, a nitrogen atmosphere or an argon atmosphere. Examples of the solvent used when the Co (CO) ₄ and / or Ge compound represented by the following general formula (3) is used as a solution include, but are not limited to, pentane and octane.
R ¹ R ² R ³ GeH (3)
(In the formula (3), R ¹ , R ² and R ³ are each independently hydrogen, non-aromatic hydrocarbon group, halogeno group or halogenated non-aromatic hydrocarbon group, provided that Non-aromatic hydrocarbon groups exclude cross-linked non-aromatic hydrocarbon groups, and halogenated non-aromatic hydrocarbon groups exclude cross-linked halogenated non-aromatic hydrocarbon groups.)

Further, the compound represented by the above general formula (1) is synthesized by dropping the Ge compound represented by the above general formula (3) neat, that is, without dissolving it in a solvent to solid Co (CO) _4. You can also Co (CO) ₄ may exist as dimer Co ₂ (CO) ₈ .

Furthermore, the compound represented by the above general formula (1) can be synthesized by dissolving the Ge compound represented by the above general formula (3) in solid Co (CO) ₄ in a solvent and dropping it. Examples of the solvent when the Ge compound is used as a solution include, but are not limited to, pentane and octane.

The Ge-containing Co film forming material represented by the general formula (2) is synthesized by adding a Ge compound represented by the following general formula (4) to a Co (CO) ₄ solution in an inert gas atmosphere. can do. Hydrogen evolution is observed during the reaction. Examples of the inert gas atmosphere include, but are not limited to, a nitrogen atmosphere or an argon atmosphere. Examples of the solvent for preparing Co (CO) ₄ and / or a Ge compound represented by the following general formula (4) as a solution include pentane and octane, but are not limited thereto.
R ⁵ R ⁶ GeH ₂ (4)
(In the formula (4), R ⁵ and R ⁶ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group. (The hydrocarbon group excludes a crosslinked non-aromatic hydrocarbon group, and the halogenated non-aromatic hydrocarbon group excludes a crosslinked halogenated non-aromatic hydrocarbon group.)

Moreover, the compound represented by the above general formula (2) is synthesized by dropping the Ge compound represented by the above general formula (4) neat, that is, without dissolving it in a solvent to solid Co (CO) _4. You can also

Furthermore, the compound represented by the above general formula (2) can also be synthesized by dissolving the Ge compound represented by the above general formula (4) in solid Co (CO) ₄ in a solvent and dropping it. Examples of the solvent when the Ge compound is used as a solution include, but are not limited to, pentane and octane.

  The reaction product containing the Ge-containing Co film forming material represented by the general formula (1) or the general formula (2) obtained as described above can be purified by refluxing and subsequent distillation. Instead of refluxing and subsequent distillation, purification may be performed by vacuum distillation or sublimation.

2. Film-forming method of Ge-containing Co film The film-forming method of Ge-containing Co film according to this embodiment is represented by the first step of introducing the substrate into the chamber and the general formula (1) or the general formula (2). A second step of introducing the Ge-containing Co film forming material into the chamber in which the substrate is disposed; and at least a part of the Ge-containing Co film forming material so as to form the Ge-containing Co film. And a third step of forming a film on the substrate. Further, the Ge-containing Co film forming method according to the present embodiment includes a group consisting of ammonia, hydrogen, inert gas, alcohol, amino alcohol, amine, GeH ₄ , Ge ₂ H ₆ and combinations thereof in the chamber. A fourth step of introducing an additive gas selected more may be further included as necessary. Specific examples of the inert gas include, but are not limited to, argon, helium, nitrogen, or a combination thereof.

  In the method for forming a Ge-containing Co film according to this embodiment, a CVD (Chemical Vapor Deposition) method or an ALD (Atomic Layer Deposition) method can be used.

  In the CVD method, after the first step, the Ge-containing Co film forming material is introduced into the chamber in the second step, and then the additive gas is introduced in the fourth step, thereby forming the third step. A membrane may be implemented. After the first step, the second step may be performed after the fourth step.

In the ALD method, following the first step, after introducing the Ge-containing Co film forming material into the chamber in the second step, the Ge-containing Co film forming material is purged from the chamber, and then the fourth step. The film forming as the third step may be performed by repeating the pulse of introducing the additive gas and removing the additive gas from the chamber by purging. The fourth step, purge, second step, and purge can be repeated in this order.

  The method for forming a Ge-containing Co film according to this embodiment can be used, for example, for forming a Ge-containing Co film on a substrate. According to the method for forming a Ge-containing Co film according to the present embodiment, the composition ratio of Ge and Co in the Ge-containing Co film to be formed is set to an arbitrary value in the range of Ge: Co = 1: 99 to 99: 1. It can be a composition. The composition ratio of Ge and Co can be arbitrarily changed depending on the characteristics of the functional group bonded to the Ge atom, the temperature at which the film is formed, and the like. The Ge-containing Co film thus formed can be suitably used as, for example, a contact layer or a barrier layer.

  Hereinafter, each step in the method for forming a Ge-containing Co film according to the present embodiment will be described with reference to the drawings. FIG. 2 is a schematic configuration diagram of a CVD apparatus suitably used in the present embodiment. FIG. 3 is a diagram showing a flow of the CVD method according to the present embodiment.

2.1. First Step The first step is a step of introducing the substrate 103 into the chamber 102 mounted in the CVD apparatus 101 as shown in FIG. At least one substrate 103 is introduced and placed in the chamber 102. The chamber 102 is not particularly limited as long as it is a chamber 102 in which film formation is performed, and specifically includes a parallel plate chamber, a cold wall chamber, a hot wall chamber, a single wafer chamber, a multi-wafer chamber, and the like. be able to.

The type of the substrate 103 on which the Ge-containing Co film is formed varies depending on the end use purpose. In some embodiments, the substrate is an oxide used as a dielectric material in MIM, DRAM or FeRam technology (eg, ZrO ₂ based material, HfO ₂ based material, TiO ₂ based material, rare earth oxide based material, ternary oxidation) Material-based materials) or nitride-based layers (eg TaN) used as an oxygen barrier between copper and low-k layers. Other substrates can be used in the manufacture of semiconductor devices, photovoltaic devices, LCD-TFT devices or flat panel devices. Examples of such substrates include solid substrates such as copper and copper alloys such as CuMn, metal nitride-containing substrates (eg, TaN, TiN, WN, TaCN, TiCN, TaSiN, and TiSiN); insulators (eg, SiO ₂ , Si ₃ N ₄ , SiON, HfO ₂ , Ta ₂ O ₅ , ZrO ₂ , TiO ₂ , Al ₂ O _3, and barium strontium titanate); or other substrates including any combination of these materials However, it is not limited to these. The actual substrate utilized will also depend on the specific compound embodiment utilized. However, in many cases, the preferred substrate utilized is selected from Si and SiO ₂ substrates.

  After the substrate 103 is introduced into the chamber 102, the temperature and pressure in the chamber 102 are adjusted as necessary. The temperature in the chamber 102 can be set to 80 ° C. or higher and 350 ° C. or lower. The pressure in the chamber 102 can be 0.1 Torr or more and 50 Torr or less. The pressure in the chamber 102 is set to a predetermined pressure by appropriately adjusting the APC valve 405 connected to the chamber 102.

  The temperature in the chamber 102 can be controlled by controlling the temperature of the substrate holder that holds the substrate 103, controlling the temperature of the wall surface of the chamber 102, or a combination thereof. A known heating device can be used for heating the substrate 103.

Although the first process using the CVD apparatus has been described above, as another embodiment, instead of the CVD apparatus 101, an ALD apparatus, a PECVD apparatus, a PEALD apparatus, a PCVD apparatus, an LPCVD apparatus, an SACVD apparatus, an APCVD apparatus, a space The substrate 103 can be introduced into a chamber mounted on an apparatus selected from the group consisting of a general ALD apparatus, a radical assisted film forming apparatus, a supercritical fluid film forming apparatus, and combinations thereof.

2.2. Second Step and Fourth Step The second step is a step of introducing a Ge-containing Co film forming material into the chamber 102 in which the substrate 103 is disposed. At this time, an additive gas selected from the group consisting of ammonia, hydrogen, inert gas, alcohol, amino alcohol, amine, GeH ₄ , Ge ₂ H ₆ and combinations thereof can be further introduced (fourth step). ). Among these, the inert gas may be any gas that does not react with the Ge-containing Co film forming material represented by the general formula (1) or the general formula (2) in the chamber 102. For example, argon, helium, It may be a gas selected from the group consisting of nitrogen and combinations thereof.

  The flow rate of the Ge-containing Co film forming material introduced into the chamber 102 is controlled by the Ge-containing Co film forming material flow rate adjusting mechanism 204. The Ge-containing Co film forming material flow rate adjusting mechanism 204 is not particularly limited as long as it is a mechanism that controls the flow rate of the Ge-containing Co film forming material, and may be, for example, a mass flow controller (hereinafter also referred to as “MFC”).

  The amount of Ge-containing Co film forming material introduced into the chamber 102 may be measured together with the carrier gas flow rate, and depends on the volume of the chamber 102, the characteristics of the Ge-containing Co film forming material, the surface area of the substrate 103, and the like. For example, the flow rate is in the range of 0.1 SCCM to 2000 SCCM. When the Ge-containing Co film forming material is introduced together with the carrier gas, the Ge-containing Co film forming material concentration in the carrier gas varies depending on the characteristics of the Ge-containing Co film forming material, the temperature of the chamber 102, the pressure, and the like.

  The vapor of the Ge-containing Co film forming material is supplied from the Ge-containing Co film forming material container 304 to the chamber 102. When the Ge-containing Co film forming material is in a liquid state, only the vapor of the Ge-containing Co film forming material can be supplied without accompanying the carrier gas, but the carrier gas is supplied to the Ge-containing Co film forming material container 304. It is also possible to introduce it with the carrier gas. The carrier gas is not particularly limited as long as the carrier gas itself does not cause a reaction with the Ge-containing Co film forming material. For example, a gas selected from the group consisting of ammonia, hydrogen, an inert gas, and combinations thereof It may be. Among these, an inert gas is more preferable. Examples of the inert gas include a gas selected from the group consisting of argon, helium, nitrogen, and combinations thereof. It is also possible to introduce a direct injection method in which a droplet of Ge-containing Co film forming material is dropped on a heater and the generated vapor is introduced.

  When the Ge-containing Co film forming material is in a solid state, the Ge-containing Co film forming material can be sublimated and supplied without accompanying the carrier gas, but the carrier gas is supplied to the Ge-containing Co film forming material container 304. It is also possible to introduce it with the carrier gas. The carrier gas is not particularly limited, and may be a gas selected from the group consisting of ammonia, hydrogen, inert gas, and combinations thereof, for example. Among these, it is more preferable to use an inert gas. Examples of the inert gas include a gas selected from the group consisting of argon, helium, nitrogen, and combinations thereof.

  The Ge-containing Co film-forming material container 304 can be heated by known heating means so that the Ge-containing Co film-forming material has a sufficient vapor pressure, if necessary. The temperature at which the Ge-containing Co film forming material container 304 is maintained is, for example, in the range of 0 ° C. or higher and 100 ° C. or lower, depending on characteristics such as thermal stability and vapor pressure of the Ge-containing Co film forming material. As the Ge-containing Co film forming material container 304, a known bubbling container, sublimation container, or the like can be used.

Ge-containing Co film forming ^{_{material, NMe 3, NEt 3, N}} i Pr 3, NMeEt 2, NC 5
Further comprising one or two neutral adduct ligands selected from the group consisting of H ₅ , OC ₄ H ₈ , Me ₂ O, Et ₂ O, Et ₂ S, ⁿ Pr ₂ S and ⁿ Bu ₂ S Good. When the Ge-containing Co film forming material is solid at the use temperature, supply to the chamber 102 can be facilitated by including a neutral adduct ligand and imparting high fluidity.

  In the fourth step, the additive gas introduced into the chamber 102 may be supplied from the additive gas container 302 to the chamber 102. In this case, the flow rate of the additive gas introduced into the chamber 102 is controlled by the additive gas flow rate adjusting mechanism 205 disposed in the additive gas supply pipe 202.

  In the fourth step, the additive gas may be introduced into the chamber 102 as a carrier gas for the Ge-containing Co film forming material. In this case, the additive gas is supplied from the additive gas container 301 and introduced into the chamber 102 via the Ge-containing Co film forming material container 304. The flow rate of the additive gas may be controlled by the Ge-containing Co film forming material flow rate adjusting mechanism 204, or may be controlled by a flow rate adjusting mechanism (not shown) arranged in the carrier gas supply pipe 401. The additive gas supplied to the Ge-containing Co film forming material container 304 as the carrier gas may be a gas selected from the group consisting of ammonia, hydrogen, an inert gas, and combinations thereof, but is preferably an inert gas. And particularly preferably nitrogen or argon.

  In the fourth step, the additive gas may be supplied from both the additive gas container 301 and the additive gas container 302 to the chamber 102. The gas supplied from the additive gas container 301 and the gas supplied from the additive gas container 302 may be the same or different. In the case of supplying different additive gases, the combination can be arbitrarily determined. For example, nitrogen gas may be supplied from the additive gas container 301 and ammonia gas may be supplied from the additive gas container 302.

2.3. Third Step The third step is a step of forming at least a part of the Ge-containing Co film forming material on the substrate 103 so as to form a Ge-containing Co film. In the third step, any CVD method known to those skilled in the art can be used to form the Ge-containing Co film on the substrate 103. The Ge-containing Co film forming material introduced into the chamber 102 is decomposed in the gas phase and formed on the substrate 103 to form a Ge-containing Co film. The Ge-containing Co film forming material may be introduced into the chamber 102 in a gas state, or may be decomposed in the gas phase after being introduced into the chamber 102 in a liquid state.

  The third step is preferably performed at a temperature of 0 ° C to 350 ° C, more preferably 100 ° C to 250 ° C, and particularly preferably 160 ° C to 200 ° C. The temperature at which the third step is performed is a temperature measured in the chamber (for example, the temperature of the substrate holder or the temperature of the inner wall of the chamber). According to the method for forming a Ge-containing Co film according to the present embodiment, a Ge-containing Co film can be formed at a low temperature, but the term “low temperature” in this specification refers to a temperature of 350 ° C. or lower. .

In addition, according to the method for forming a Ge-containing Co film according to the present embodiment, it is possible to obtain a substantially uniform Ge-containing Co film having a desired stoichiometric ratio of Ge and Co at a suitable film formation rate. It becomes. Specifically, when Et ₃ Ge—Co (CO) ₄ is used as a Ge-containing Co film forming material, a Co-rich Ge-containing Co film is formed when the film is formed at a lower temperature (for example, 0 ° C. to 200 ° C.). When a film is formed at a higher temperature (for example, 300 ° C. to 350 ° C.), a Ge-rich Ge-containing Co film can be obtained. This indicates that the stoichiometric ratio of Ge and Co in the deposited film can be controlled by the deposition temperature.

  In the method for forming a Ge-containing Co film according to this embodiment, the pressure in the chamber is preferably 0.06 Torr to atmospheric pressure, more preferably 0.1 Torr to 30 Torr, and particularly preferably 1 Torr to 15 Torr. be able to. When the pressure in the chamber is within the above range, a state where an appropriate amount of the Ge-containing Co film forming material is present in the chamber is maintained, and the Ge-containing Co film can be formed at a suitable film formation rate.

  The additive gas can be treated with plasma to decompose the additive gas into its radical form. The plasma may be generated or may be present in the chamber 102 itself. The plasma may be located away from the chamber 102, for example in a remotely installed plasma system.

  For example, an additive gas may be introduced into a DC plasma reactor (not shown) that generates plasma installed in the chamber 102 to generate a plasma processing reaction gas in the chamber 102. An exemplary direct current plasma reactor includes the Titan ™ PECVD system from Trion Technologies. The additive gas can be introduced and held in the chamber 102 before the plasma treatment. As another embodiment, the plasma treatment may be performed simultaneously with the introduction of the additive gas. In situ plasma is typically 13.56 MHz RF capacitively coupled plasma generated between the showerhead and the substrate holder. The substrate or showerhead may be a power electrode depending on whether cation collisions occur. Typical applied power in an in situ plasma generator is about 50W to about 1000W. Reaction gas dissociation using in situ plasma is usually not achieved using a remote plasma source with the same power input, and therefore reactive gas dissociation is not as efficient as a remote plasma system and can be damaged by the plasma. This may be useful for forming a Ge-containing Co film on the substrate 103 which is easy to use.

  The Ge-containing Co film deposition material and one or more additive gases can be introduced into the chamber 102 simultaneously (CVD), sequentially (ALD), or other combinations. For example, the Ge-containing Co film forming material can be introduced in one pulse, and the additive gas can be introduced together in separate pulses. The chamber 102 may already contain an additive gas before introducing the Ge-containing Co film forming material.

In the present embodiment, the case where the third process is performed by the CVD method has been described. However, instead of the CVD method, atomic layer deposition (ALD), plasma enhanced chemical vapor deposition (PECVD), plasma enhanced atomic layer deposition (PEALD) ), Pulsed chemical vapor deposition (PCVD), low pressure chemical vapor deposition (LPCVD), low pressure chemical vapor deposition (SACVD), atmospheric pressure chemical vapor deposition (APCVD), spatial ALD, radical assisted deposition, supercritical fluid deposition, and combinations thereof May be selected from the group consisting of
For example, a Ge-containing Co film forming material may be continuously introduced into the chamber 102 and another additive gas may be introduced by pulses (PCVD). The additive gas can be passed through a plasma system localized in the chamber 102 or remote from the chamber 102 and decomposed into radicals. In either case, a purge or evacuation step can be performed following the pulse to remove excess components introduced. In any case, the pulse lasts for a period in the range of about 0.01 seconds to about 30 seconds, alternatively about 0.3 seconds to about 3 seconds, alternatively about 0.5 seconds to about 2 seconds. Can do.
For example, a susceptor that holds several wafers can be rotated while simultaneously spraying a Ge-containing Co film deposition material and one or more additive gases from a showerhead (spatial ALD).

The Ge-containing Co film formed on the substrate 103 may have a Ge: Co composition ratio of Ge: Co = 1: 99 to 99: 1, preferably 1:99 to 70:30. Ge-containing Co
The composition ratio of Ge and Co in the film can be set to a desired composition ratio depending on the type of the Ge-containing Co film forming material to be introduced, the temperature and pressure in the chamber 102. The composition ratio of Ge and Co can be arbitrarily changed depending on the characteristics of the functional group bonded to the Ge atom, the temperature and pressure during film formation, and the like.

  The thickness of the Ge-containing Co film formed on the substrate 103 is preferably 0.1 nm or more and 400 nm or less. For example, when a Ge-containing Co film is formed on a substrate provided with a recess, a barrier layer can be formed by forming a Ge-containing Co film having a desired thickness in the recess of the substrate. When the Ge-containing Co film is used as a barrier layer, the thickness of the Ge-containing Co film is more preferably from 0.1 nm to 30 nm, and particularly preferably from 0.1 nm to 10 nm. When a Ge-containing Co film is formed on the flat portion on the substrate, the Ge-containing Co film can be used as a contact layer. When the Ge-containing Co film is used as the contact layer, the thickness of the Ge-containing Co film is more preferably from 0.1 nm to 50 nm, and particularly preferably from 0.1 nm to 20 nm. In order to obtain a Ge-containing Co film having a desired film thickness, the Ge-containing Co film forming material can be continuously introduced into the chamber 102 until the desired film thickness is obtained. When the Ge-containing Co film forming material is introduced into the chamber 102 by pulses, a desired film thickness can be obtained by changing the number of pulses.

  Further, in order to obtain a Ge-containing Co film having a desired film thickness, the obtained Ge-containing Co film is subjected to thermal annealing, furnace annealing, rapid thermal annealing, UV curing or electron beam curing and / or plasma gas exposure as necessary. It may be subjected to further processing such as. Known systems can be utilized to perform these additional processing steps. For example, a Ge-containing Co film may be subjected to a temperature in the range of approximately 200 ° C. to approximately 1000 ° C. under an inert atmosphere, a hydrogen-containing atmosphere, a nitrogen-containing atmosphere, an oxygen-containing atmosphere, or a combination thereof for approximately 0.1 seconds to approximately The exposure can be for a time in the range of 7200 seconds. Preferably, the temperature is in the range of 350 ° C. to 450 ° C. for 3000 seconds to 4000 seconds in an H-containing atmosphere. Since the resulting film contains fewer impurities, the density can be improved and, as a result, the leakage current can be improved. The annealing step can be performed in the same reaction chamber that performs the deposition process. Alternatively, the substrate may be removed from the reaction chamber and the annealing / flash annealing process performed in a separate device. Any of the above post-treatment methods, particularly thermal annealing, are expected to effectively reduce any carbon and nitrogen contamination of the cobalt-containing film. This is expected to improve the resistivity of the film.

  The bulk resistance value of the Ge-containing Co film is preferably 6 μΩ · cm to 300 μΩ · cm, more preferably 10 μΩ · cm to 250 μΩ · cm, and particularly preferably 10 μΩ · cm to 60 μΩ · cm. is there. When the bulk resistance value of the Ge-containing Co film is in the above range, the bulk resistance value is sufficiently low, which is suitable as a barrier layer or a contact layer that requires a low bulk resistance value.

  The surface roughness (RMS) of the Ge-containing Co film is, for example, not less than 0.01 nm and not more than 15 nm. When the surface roughness of the obtained Ge-containing Co film is within the above range, it can be evaluated that the film surface is flat, and it can be said that the film is suitable as a barrier layer and / or a contact layer. The “surface roughness” in this specification refers to the root mean square roughness (RMS) of the film measured by AFM when the measurement range is 10 μm × 10 μm.

The Ge-containing Co film preferably has a minimum continuous film thickness of 1 nm to 5 nm. The “minimum continuous film thickness” in this specification is the resistance value (hereinafter referred to as “R”) of the film to be measured with respect to the film thickness of the film to be measured (hereinafter referred to as “d”). A value (R × d ³ ) obtained by multiplying the cube of the film thickness (d) is plotted, and the film thickness at which the value of R × d ³ is minimized. When the minimum continuous film thickness of the Ge-containing Co film is in the above range, a Ge-containing Co film with few pinholes is obtained,
A device having good electrical characteristics can be obtained.

  When the Ge-containing Co film is formed on a substrate having at least one recess, the Ge-containing Co film is formed on the surface of the substrate with respect to the film thickness (x in FIG. 1) of the Ge-containing Co film. The film thickness of the Ge-containing Co film formed on the inner wall surface of the recess (y in FIG. 1) and / or the film thickness of the Ge-containing Co film formed on the inner bottom surface of the recess (in FIG. The ratio of z) can be preferably 0.2 or more and 1.1 or less, more preferably 0.5 or more and 1.1 or less, and particularly preferably 0.9 or more and 1.1 or less. In addition, the film thickness of the inner wall surface of the said recessed part is acquired by measuring the film thickness of the inner wall surface in the height (1/2 Dep) of 1/2 of the depth (it is set as Dep) of a recessed part. According to the method for forming a Ge-containing Co film according to the present embodiment, even when the film is formed on a substrate having at least one recess, the uniformity of the film thickness is excellent between the surface of the substrate and the recess. A Ge-containing Co film can be formed. The ratio of the film thickness of the inner wall surface or the inner bottom surface of the recess to the film thickness of the substrate surface is evaluated by the above-described step coverage.

2.4. Final Step After the Ge-containing Co film is formed on the substrate 103, when the Ge-containing Co film forming material and the additive gas are used, the additive gas is removed from the chamber 102 by purging. Further, the pressure in the chamber 102 is returned to atmospheric pressure by the APC valve 405, the temperature in the chamber 102 is returned to room temperature by the temperature adjusting mechanism, and the substrate 103 is taken out.

3. EXAMPLES Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

Example 1 Synthesis of Et ₃ Ge—Co (CO) ₄ Co ₂ (CO) ₈ (16.3 g, 0.048 mol) was introduced into a 250 mL three-necked flask containing a magnetic stirrer. The inside of the three-necked flask is a nitrogen gas atmosphere. The three-necked flask is equipped with a stopcock, a dropping funnel with a capacity of 50 mL, and a thermocouple. Et ₃ GeH (15.33 g, 0.095 mol) was introduced into the dropping funnel using a cannula. The three-necked flask was placed in an ice bath at 0 ° C. In order to completely dissolve Co ₂ (CO) ₈ , 50 mL of pentane was introduced into the three-necked flask using a cannula. Et ₃ GeH was dropped from the dropping funnel into the three-necked flask. Although exothermic reaction accompanied with hydrogen gas generation occurred, the dropping was gradually performed so that hydrogen gas generation and temperature increase did not occur suddenly. After the dropwise addition of Et ₃ GeH, after the generation of hydrogen gas was completed, the mixture was stirred at room temperature for 15 hours. A brown crude product was obtained. The dropping funnel was removed under an inert gas atmosphere, a Vigreux tube and a condenser were attached to the three-necked flask, and the crude product was purified by vacuum distillation. 21.7 g of 97% pure Et ₃ Ge—Co (CO) ₄ was obtained. The isolation yield was 69%. Et ₃ Ge—Co (CO) ₄ is a yellow liquid.

FIG. 4 is a thermal analysis result of Et ₃ Ge—Co (CO) ₄ obtained above. As shown by the solid line in FIG. 4, in thermogravimetric analysis (TGA), the residue under atmospheric pressure (1009 mbar) and open cup conditions was 1.56%. A TGA / DSC 3+ manufactured by METTLER TOLEDO was used as the thermogravimetric analyzer.

FIG. 5 is a mass spectrum analysis result of Et ₃ Ge—Co (CO) ₄ obtained above. As shown in FIG. 5, in mass spectral analysis (MS), molecular ion peak M + 331 (Et ₃ Ge—Co (CO) ₄ ion), CO desorbed fragment 303 (Et ₃ Ge—Co (CO) ₃ ) Ion). The mass spectrum analyzer used was an Agilent 5975 Series MSD, Triple Axis HED-EM detector.

FIG. 6 is a ¹ H-NMR analysis result of Et ₃ Ge—Co (CO) ₄ obtained above. As shown in FIG. 6, in nuclear magnetic resonance (NMR), ¹ H-NMR was measured using C ₆ D ₆ as a heavy solvent and tetramethylsilane as an internal reference. As a result, Et ₃ Ge—Co ( The structure of CO) ₄ was confirmed. ¹ H-NMR (δ, C ₆ D ₆ ): 1.06 ppm (t, 6H, —CH ₃ ), 1.14 ppm (q, 4H, —CH ₂ ).

FIG. 7 shows the results of ¹³ C-NMR analysis of Et ₃ Ge—Co (CO) ₄ obtained above. As shown in FIG. 7, ¹³ C-NMR was measured using tetramethylsilane as an internal standard, using C ₆ D ₆ as a heavy solvent, and the structure of Et ₃ Ge—Co (CO) ₄ was confirmed. It was done. ¹³ C-NMR (δ, C ₆ D ₆ ): 10 ppm (s, —CH ₃ ), 15 ppm (s, CH ₂ ), 200 ppm (brs, —CO). A 400 MHz NMR apparatus manufactured by JEOL was used as the NMR analyzer.

FIG. 8 shows the vapor pressure measurement result of Et ₃ Ge—Co (CO) ₄ obtained above. As shown in FIG. 8, as a result of measuring the vapor pressure with a TGA / DSC 3+ manufactured by METTLER TOLEDO in the thermogravimetric analyzer, the vapor pressure of Et ₃ Ge—Co (CO) ₄ at 60 ° C. is about 1.1 Torr. Met. The measurement conditions were a nitrogen gas flow rate of 220 SCCM, a heating rate of 10 ° C./min, and the vapor pressure was determined by isothermal thermogravimetry.

FIG. 9 shows measurement results of temperature and pressure characteristics of Et ₃ Ge—Co (CO) ₄ obtained above. As shown in FIG. 9, using a quartz pressure sensor _{TSU Et 3 Ge-Co (CO} ) results of temperature and pressure characteristics were measured in _{4, Et 3 Ge-Co (} CO) 4 is thermally to 90 ° C. It was stable and it was confirmed that thermal decomposition occurred at a temperature of 90 ° C. or higher. HEL II manufactured by HEL was used for measurement of temperature and pressure characteristics.

FIG. 10 is a measurement result of the thermal stability of Et ₃ Ge—Co (CO) ₄ obtained above. As shown in FIG. 10, the thermal stability of Et ₃ Ge—Co (CO) ₄ was measured using a quartz pressure sensor TSU. As a result, Et ₃ Ge—Co (CO) ₄ did not increase in pressure at 65 ° C. for 24 hours. Therefore, it was confirmed that Et ₃ Ge—Co (CO) ₄ is thermally stable at 65 ° C. HEL II manufactured by HEL was used for measurement of temperature and pressure characteristics.

Example _{2: Et 3 Ge-Co (} CO) 4 thermal CVD
Et ₃ Ge—Co (CO) ₄ was used as a Ge-containing Co film forming material, and a Ge-containing Co film was formed on the substrate by a thermal CVD method under the following conditions without using an additive gas. The XPS analysis results of the film thus obtained are shown in FIG. 11, and the SEM analysis results are shown in FIGS.
<Film formation conditions>
Apparatus used: An apparatus having the configuration shown in FIG. 2 was used. A shower head for supplying the Ge-containing Co film forming material and the carrier gas introduced into the chamber 102 to the substrate 103 held by the substrate holder in the chamber 102 is attached to the chamber (102) in FIG. ing. The film formation temperature was controlled by controlling the temperature of the substrate holder.
Ge-containing Co film forming material: Et ₃ Ge—Co (CO) ₄
・ Substrate: SiO ₂ (cleaned with HF)
・ Film formation temperature: 200 ℃
-Chamber pressure: 10 Torr
-Ge-containing Co film forming material container temperature: 50 ° C
・ Carrier gas: Nitrogen gas ・ Carrier gas flow rate: 50 SCCM
-Film formation time: 60 minutes-XPS: K-Alpha manufactured by Thermo Scientific
-SEM: S-5200 manufactured by Hitachi, Ltd.
Resistance meter: Keithley source meter 4ZA4
AFM: MFP-3D manufactured by Asylum Research

  FIG. 11 shows the result of XPS analysis of the Ge-containing Co film obtained above. As shown in FIG. 11, from the analysis result by XPS, Co atoms were detected in the bulk of the obtained Ge-containing Co film in an abundance ratio of about 60% and Ge atoms of about 40%. It can be seen that a Co-rich CoGe film, which is a Co film, is formed. The obtained Ge-containing Co film has a carbon content in the bulk of less than 1%, and it can be said that a Ge-containing Co film with few carbon impurities was obtained.

  FIG. 12 shows the SEM analysis result of the Ge-containing Co film obtained above. As shown in FIG. 12, the thickness of the obtained Ge-containing Co film was about 50 nm. Since the film formation time was 60 minutes, the film formation rate was 0.83 nm / min.

  FIG. 13 shows the SEM analysis result of the Ge-containing Co film obtained above. As shown in FIG. 13, the obtained Ge-containing Co film was a uniform and conformal film.

The step coverage of the Ge-containing Co film formed in the trench having the groove width of 2 μm and the aspect ratio (groove width: depth) of 1: 7 was as follows.
The film thickness of the Ge-containing Co film formed on the inner wall surface of the recess (y in FIG. 1) with respect to the film thickness of the Ge-containing Co film formed on the surface of the substrate (x in FIG. 1). ) Ratio was 0.50 (y / x = 0.50).
The film thickness of the Ge-containing Co film formed on the inner bottom surface of the recess (z in FIG. 1) relative to the film thickness of the Ge-containing Co film formed on the surface of the substrate (x in FIG. 1) ) Ratio was 0.29 (z / x = 0.29).

The step coverage of the Ge-containing Co film formed in the trench having an open groove width of 0.25 μm and an aspect ratio (open groove width: depth) of 1:20 was as follows.
The film thickness of the Ge-containing Co film formed on the inner wall surface of the recess (y in FIG. 1) with respect to the film thickness of the Ge-containing Co film formed on the surface of the substrate (x in FIG. 1). ) Ratio was 0.44 (y / x = 0.44).
The film thickness of the Ge-containing Co film formed on the inner bottom surface of the recess (z in FIG. 1) relative to the film thickness of the Ge-containing Co film formed on the surface of the substrate (x in FIG. 1) ) Ratio was 0.36 (z / x = 0.36).

  The bulk resistance value of the obtained Ge-containing Co film was measured by a resistance meter and found to be 204 μΩ · cm.

  The surface roughness (RMS, root mean square roughness) of the obtained Ge-containing Co film was measured by AFM and found to be 0.97 nm (the measurement range was 10 μm × 10 μm).

As another example, the same process as in Example 2 was performed using TiN as a substrate. As a result, the same result as in Example 2 was obtained. That is, a Ge-containing Co film containing about 60% Co and about 40% Ge was obtained by thermal CVD of Et ₃ Ge—Co (CO) ₄ .

Example _{3: Et 3 Ge-Co (} CO) 4 thermal CVD
A Ge-containing Co film was formed on the substrate by a thermal CVD method under the same conditions as in Example 2 except that the pressure in the chamber was 1 Torr. Table 1 shows the results of measurement of the obtained Ge-containing Co film.

Here, description items in Table 1 will be described.
The film thickness is the thickness (nm) of the Ge-containing Co film measured by SEM.
The film formation speed is a value (nm / min) obtained by dividing the obtained film thickness by the film formation time.
The bulk resistance value is a value (μΩ · cm) measured with an ohmmeter.
The Co / Ge ratio is the composition ratio of Co and Ge in the Ge-containing Co film obtained by XPS measurement.
SC _{1: 7} (y / x) refers to the film thickness (x in FIG. 1) of the Ge-containing Co film formed on the surface of the substrate, measured in a trench with an aspect ratio of 1: 7. It is the ratio of the film thickness (y in FIG. 1) of the Ge-containing Co film formed on the inner wall surface of the recess.
SC _{1: 7} (z / x) refers to the film thickness (x in FIG. 1) of the Ge-containing Co film formed on the surface of the substrate measured in a trench having an aspect ratio of 1: 7. It is the ratio of the film thickness (z in FIG. 1) of the Ge-containing Co film formed on the inner bottom surface of the recess.
SC _1:20 (y / x) refers to the thickness of the Ge-containing Co film formed on the surface of the substrate (x in FIG. 1) measured in a trench with an aspect ratio of 1:20. It is the ratio of the film thickness (y in FIG. 1) of the Ge-containing Co film formed on the inner wall surface of the recess.
SC _1:20 (z / x) refers to the film thickness (x in FIG. 1) of the Ge-containing Co film formed on the surface of the substrate, measured in a trench with an aspect ratio of 1:20. It is the ratio of the film thickness (z in FIG. 1) of the Ge-containing Co film formed on the inner bottom surface of the recess.
-Surface roughness is the root mean square roughness (RMS) of the film | membrane measured by AFM when a measurement range is 10 micrometers x 10 micrometers.

Example _{4: Et 3 Ge-Co (} CO) 4 thermal CVD
A Ge-containing Co film was formed on the substrate by a thermal CVD method under the same conditions as in Example 2 except that the pressure in the chamber was 16 Torr. Table 1 shows the results of measurement of the obtained Ge-containing Co film.

Example _{5: Et 3 Ge-Co (} CO) 4 thermal CVD
A Ge-containing Co film was formed on the substrate by thermal CVD under the same conditions as in Example 2 except that the film formation time was 20 minutes and H ₂ was used in addition to the carrier gas (nitrogen gas 50 SCCM) as the additive gas. A film was formed. The amount of H ₂ gas introduced was 10 SCCM. Table 1 shows the results of measurement of the obtained Ge-containing Co film.

Example _{6: Et 3 Ge-Co (} CO) 4 thermal CVD
A Ge-containing Co film was formed on the substrate by thermal CVD under the same conditions as in Example 2 except that the film formation time was 20 minutes and H ₂ was used in addition to the carrier gas (nitrogen gas 50 SCCM) as the additive gas. A film was formed. The amount of H ₂ gas introduced was 500 SCCM. Table 1 shows the results of measurement of the obtained Ge-containing Co film.

It was confirmed that a Co-rich Ge-containing Co film can be obtained when the film formation temperature is 200 ° C. and a relatively low temperature and the pressure in the chamber is in the range of 1 Torr to 16 Torr. When compared with the case where a Co-containing film and a Ge-containing film are separately formed and then annealed to form a Ge-containing Co film, according to Examples 2 to 6, a Ge-containing Co film is formed at an extremely low temperature. I was able to film. It was confirmed that a Co-rich Ge-containing Co film was obtained in the same manner when H ₂ gas was used as the additive gas. The bulk resistance value was 300 μΩ · cm or less under any condition, and good results were obtained. The step coverage was as good as 0.25 or more in the trench having an aspect ratio of 1: 7. In any of Examples 2 to 6, it can be said that the Ge-containing Co film having a small amount of carbon impurities was obtained because the carbon content in the bulk of the obtained Ge-containing Co film was less than 1%. The Ge-containing Co film obtained in Example 2 has a surface roughness of 0.97 nm and can be said to be a very flat film.

Example _{7: Et 3 Ge-Co (} CO) 4 thermal CVD
A Ge-containing Co film was formed on the substrate by thermal CVD under the same conditions as in Example 2 except that the film formation temperature was 300 ° C. and the chamber internal pressure was 1 Torr. Table 2 shows the results of measurement of the obtained Ge-containing Co film.

Example _{8: Et 3 Ge-Co (} CO) 4 thermal CVD
A Ge-containing Co film was formed on the substrate by thermal CVD under the same conditions as in Example 2 except that the film formation time was 20 minutes, the film formation temperature was 300 ° C., and the pressure in the chamber was 1 Torr. . The amount of NH ₃ gas introduced was 10 SCCM. Table 2 shows the results of measurement of the obtained Ge-containing Co film.

Example _{9: Et 3 Ge-Co (} CO) 4 thermal CVD
Same as Example 2 except that the film formation time was 20 minutes, the film formation temperature was 300 ° C., the pressure in the chamber was 1 Torr, and NH ₃ gas was used in addition to the carrier gas (nitrogen gas 50 SCCM) as the additive gas. Under these conditions, a Ge-containing Co film was formed on the substrate by a thermal CVD method. The amount of NH ₃ gas introduced was 500 SCCM. Table 2 shows the results of measurement of the obtained Ge-containing Co film.

Example _{10: Et 3 Ge-Co (} CO) 4 thermal CVD
Same as Example 2 except that the film formation time was 20 minutes, the film formation temperature was 300 ° C., the pressure in the chamber was 1 Torr, and H ₂ gas was used in addition to the carrier gas (nitrogen gas 50 SCCM) as the additive gas. Under these conditions, a Ge-containing Co film was formed on the substrate by a thermal CVD method. The amount of H ₂ gas introduced was 10 SCCM. Table 2 shows the results of measurement of the obtained Ge-containing Co film.

Example _{11: Et 3 Ge-Co (} CO) 4 thermal CVD
Same as Example 2 except that the film formation time was 20 minutes, the film formation temperature was 300 ° C., the pressure in the chamber was 1 Torr, and H ₂ gas was used in addition to the carrier gas (nitrogen gas 50 SCCM) as the additive gas. Under these conditions, a Ge-containing Co film was formed on the substrate by a thermal CVD method. The amount of H ₂ gas introduced was 500 SCCM. Table 2 shows the results of measurement of the obtained Ge-containing Co film.

Example _{12: Et 3 Ge-Co (} CO) 4 thermal CVD
A Ge-containing Co film was formed on the substrate by a thermal CVD method under the same conditions as in Example 2 except that the film formation temperature was 300 ° C. Table 2 shows the results of measurement of the obtained Ge-containing Co film.

Example _{13: Et 3 Ge-Co (} CO) 4 thermal CVD
A film formation time of 20 minutes, a film formation temperature of 300 ° C., and a carrier gas (nitrogen gas 50 SCCM) as an additive gas was used on the substrate under the same conditions as in Example 2 except that H ₂ gas was used. A Ge-containing Co film was formed by thermal CVD. The amount of H ₂ gas introduced was 10 SCCM. Table 2 shows the results of measurement of the obtained Ge-containing Co film.

Example _{14: Et 3 Ge-Co (} CO) 4 thermal CVD
A film formation time of 20 minutes, a film formation temperature of 300 ° C., and a carrier gas (nitrogen gas 50 SCCM) as an additive gas was used on the substrate under the same conditions as in Example 2 except that H ₂ gas was used. A Ge-containing Co film was formed by thermal CVD. The amount of H ₂ gas introduced was 500 SCCM. Table 2 shows the results of measurement of the obtained Ge-containing Co film.

From the results shown in Table 2, it was confirmed that a Ge-rich Ge-containing Co film was obtained when the pressure in the chamber was in the range of 1 Torr to 10 Torr under the relatively high temperature condition of 300 ° C. Compared with the case where a Co-containing film and a Ge-containing film are separately formed and then annealed to form a Ge-containing Co film, according to this example, a Ge-containing Co film is formed at a low temperature. I was able to. Further, when a Co-rich film is desired, the film is formed at a relatively low temperature of about 200 ° C., and when a Ge-rich film is desired, the film is formed at a relatively high temperature of about 300 ° C. It was confirmed that the / Ge composition ratio can be controlled. It was confirmed that a Ge-rich Ge-containing Co film was obtained in the same manner when NH ₃ gas and H ₂ gas were used as additive gases. The bulk resistance value was 100 μΩ · cm or less under any condition, and a very good result was obtained. The step coverage was as good as 0.2 or more in the trench having an aspect ratio of 1: 7. In any of Examples 7 to 14, the carbon content in the bulk of the obtained Ge-containing Co film was less than 1%, and it can be said that a Ge-containing Co film with few carbon impurities was obtained. Further, the Ge-containing Co film obtained in Example 7 has a surface roughness of 6.1 nm, and the Ge-containing Co film obtained in Example 10 has a surface roughness of 3.7 nm. Any film can be said to be a flat film.

  In general, a film forming method capable of obtaining a film having a high film forming speed and a small bulk resistance value is desired. In Example 10, the film forming speed was very high at 5.20 nm / min. Good results were obtained in which the bulk resistance of the film was very low at 55.1 μΩ · cm. Further, under the conditions of Example 7, the film formation rate was very fast as 4.60 nm / min, and the bulk resistance value of the obtained film was as extremely low as 37.5 μΩ · cm, and further satisfactory results were obtained.

Example 15: Synthesis of Et ₃ GeCo (CO) ₄ · 2NEt ₃ Et ₃ GeCo (CO) ₄ is added to a 100 mL flask with toluene or dichloromethane. Cool the solution at −15 ° C. and slowly add liquid triethylamine. After the amine is added, the mixture is allowed to warm to room temperature with continued stirring to complete the reaction. After overnight reaction, excess triethylamine is removed under vacuum. The resulting product can be purified by distillation or sublimation under vacuum. In this way, Et ₃ GeCo (CO) ₄ · 2NEt ₃ can be synthesized.

Example 16: Synthesis of (CO) ₄ CoGe (Et) Me ₂ Co ₂ (CO) ₈ is added to a 100 mL flask. GeHEtMe ₂ is slowly added dropwise to the flask at 0 ° C. The mixture is allowed to warm to room temperature with continued stirring to complete the reaction. Hydrogen gas evolves after 5 minutes of stirring. Excess GeHEtMe ₂ is removed as a gas at room temperature under vacuum after 1 hour of stirring. The resulting product can be purified by vacuum distillation. In this way, (CO) ₄ CoGe (Et) Me ₂ can be synthesized. The compound has a structure in which two of the ethyl groups of Et ₃ Ge—Co (CO) ₄ are substituted with methyl groups, and its physical and chemical properties are similar to those of Et ₃ Ge—Co (CO) ₄ . Since it is thought that it is similar, it is estimated that the same result is obtained by using (CO) ₄ CoGe (Et) Me ₂ instead of Et ₃ Ge—Co (CO) ₄ in Examples 2 to 6.

Example 17: Synthesis of (CO) ₄ CoGeEt ₂ Co (CO) ₄ Co ₂ (CO) ₈ is added to a 100 mL flask. GeHEt ₂ is slowly added dropwise to the flask at 0 ° C. The mixture is allowed to warm to room temperature with continued stirring to complete the reaction. Hydrogen gas evolves after 5 minutes of stirring. Excess GeHEt ₂ is removed as a gas at room temperature under vacuum after 1 hour of stirring. The resulting product can be purified by vacuum distillation. In this way, (CO) ₄ CoGeEt ₂ Co (CO) ₄ can be synthesized.

Example 18: Thermal CVD of (CO) ₄ CoGeEt ₂ Co (CO) ₄
Applicants use (CO) ₄ CoGeEt ₂ Co (CO) ₄ as the Ge-containing Co film forming material, and form a Ge-containing Co film on the substrate by thermal CVD as in Example 2. I think you can. (CO) ₄ CoGeEt ₂ Co (CO) ₄ is expected to be able to perform thermal CVD as well because its vapor pressure and chemical properties are thought to approximate that of CoGeEt ₃ Co (CO) ₄ .

Example ^19: Prophetic ALD of ^{R 1 R 2 R 3 Ge-} Co (CO) 4
By using any of R ¹ R ² R ³ Ge—Co (CO) ₄ disclosed as a Ge-containing Co film forming material, the applicants added hydrogen using an ALD method known in the art. It is considered that a Ge-containing Co film can be formed using a gas. The group of compounds is similar in that it does not have an aromatic group as a ligand for Ge, and its vapor pressure and chemical properties are considered to be close to those of CoGeEt ₃ Co (CO) ₄ . It is predicted that a Ge-containing Co film can be formed by the reaction.

Example ^20: Another predictive ALD of ^{R 1 R 2 R 3 Ge-} Co (CO) 4
Applicants use any of the R ¹ R ² R ³ Ge—Co (CO) ₄ disclosed as Ge-containing Co film forming materials to add ammonia using an ALD method known in the art. It is considered that a Ge-containing Co film can be formed using a gas. Ammonia can react with R ¹ R ² R ³ Ge—Co (CO) ₄ similarly to hydrogen shown in Example 11 to form a Ge-containing Co film.

Example ^21: Another predictive ALD of ^{R 1 R 2 R 3 Ge-} Co (CO) 4
By using any of R ¹ R ² R ³ Ge—Co (CO) ₄ disclosed as a Ge-containing Co film forming material, the applicants can use hydrogen and ammonia using an ALD method known in the art. It is considered that a Ge-containing Co film (GeCoN film) containing N can be formed by using as an additive gas. The compound group represented by R ¹ R ² R ³ Ge—Co (CO) ₄ is considered to have a physical and chemical property approximate to that of GeEt ₃ Co (CO) _4. Is expected to be obtained.

Example _{^{22: Co (CO) 4 R}} 4 R 5 predictive ALD of Ge-Co _{(CO) 4}
By using any of Co (CO) ₄ R ⁴ R ⁵ Ge—Co (CO) ₄ disclosed as a Ge-containing Co film forming material, the applicants use an ALD method known in the art, It is considered that a Ge-containing Co film can be formed using hydrogen as an additive gas. Since it is considered that (CO) ₄ CoGeEt ₂ Co (CO) ₄ is similar in vapor pressure and chemical properties to CoGeEt ₃ Co (CO) _4, it is predicted that ALD can be carried out in the same manner as in Example 11. The

Example _{^{23: Co (CO) 4 R}} 4 R 5 Ge-Co (CO) Another predictive ALD of ₄
By using any of Co (CO) ₄ R ⁴ R ⁵ Ge—Co (CO) ₄ disclosed as a Ge-containing Co film forming material, the applicants use an ALD method known in the art, It is considered that a Ge-containing Co film can be formed using ammonia as an additive gas. The Ge-containing Co film according to this example can be formed in the same manner as in Example 12, and the Ge-containing Co film is expected to contain nitrogen. Since Co (CO) ₄ R ⁴ R ⁵ Ge—Co (CO) ₄ is considered to have physical and chemical properties similar to R ¹ R ² R ³ Ge—Co (CO) ₄ , Example 12 It is expected that a film similar to will be obtained.

Example _{^{24: Co (CO) 4 R}} 4 R 5 Ge-Co (CO) Another predictive ALD of ₄
By using any of Co (CO) ₄ R ⁴ R ⁵ Ge—Co (CO) ₄ disclosed as a Ge-containing Co film forming material, the applicants use an ALD method known in the art, It is considered that a Ge-containing Co film can be formed using hydrogen and ammonia as additive gases. This is because the physical and chemical properties of the compound group represented by Co (CO) ₄ R ⁴ R ⁵ Ge—Co (CO) ₄ are considered to approximate that of GeEt ₃ Co (CO) ₄ .

Example _{25: Et 2 Ge- (Co (} CO) 4) 2 Synthesis _{Co 2 (CO) 8 (16.3g} , 0.048mol) was introduced into a three-necked flask 250mL containing the magnetic stirrer. The inside of the three-necked flask is a nitrogen gas atmosphere. The three-necked flask is equipped with a stopcock, a dropping funnel with a capacity of 50 mL, and a thermocouple. Et ₂ GeH ₂ (7 g, 0.053 mol) was introduced into the dropping funnel using a cannula. The three-necked flask was placed in an ice bath at 0 ° C. In order to completely dissolve Co ₂ (CO) ₈ , 50 mL of pentane (n-hexane may be used in place of pentane) was introduced into the three-necked flask using a cannula. Et ₂ GeH ₂ was dropped from the dropping funnel into the three-necked flask. Although exothermic reaction accompanied with hydrogen gas generation occurred, the dropping was gradually performed so that hydrogen gas generation and temperature increase did not occur suddenly. After dropwise addition of Et ₂ GeH ₂ , after the generation of hydrogen gas was completed, the mixture was stirred at room temperature for 15 hours. A brown crude product was obtained. The dropping funnel was removed under an inert gas atmosphere, a Vigreux tube and a condenser were attached to the three-necked flask, and the crude product was purified by vacuum distillation at a pressure of 50 mTorr. Et ₂ GeH ₂ and the solvent after the initial boiling mainly containing, three-necked _Et temperature of 98% purity is a liquid colored brown when it is about 95 ° C. of the flask 2 Ge- (Co _{(CO) 4} 14 g of ₂ was obtained. The isolation yield was 60%.

FIG. 14 shows the thermal analysis result of Et ₂ Ge— (Co (CO) ₄ ) ₂ obtained above. As indicated by the solid line in FIG. 14, in thermogravimetric analysis (TGA), the residue under open cup conditions was 2.95% under reduced pressure (20 mbar). A TGA / DSC 3+ manufactured by METTLER TOLEDO was used as the thermogravimetric analyzer.

FIG. 15 is a ¹ H-NMR analysis result of Et ₂ Ge— (Co (CO) ₄ ) ₂ obtained above. As shown in FIG. 15, in nuclear magnetic resonance (NMR), ¹ H-NMR was measured using C ₆ D ₆ as a heavy solvent and tetramethylsilane as an internal standard. As a result, Et ₂ Ge— (Co The structure of (CO) ₄ ) ₂ was confirmed. ¹ H-NMR (δ, C ₆ D ₆ ): 0.95 ppm (t, 6H, —CH ₃ ), 1.4 ppm (q, 4H, —CH ₂ ).

FIG. 16 is a ¹³ C-NMR analysis result of Et ₂ Ge— (Co (CO) ₄ ) ₂ obtained above. As shown in FIG. 16, similarly, C ₆ D ₆ was used as a heavy solvent and ¹³ C-NMR was measured using tetramethylsilane as an internal standard. As a result, Et ₂ Ge— (Co (CO) ₄ ) ₂ The structure was confirmed. ¹³ C-NMR (δ, C ₆ D ₆ ): 10.42 ppm (s, —CH ₃ ), 19.13 ppm (s, CH ₂ ), 205.08 ppm (s, —CO). A 400 MHz NMR apparatus manufactured by JEOL was used as the NMR analyzer.

FIG. 17 shows the vapor pressure measurement results of Et ₂ Ge— (Co (CO) ₄ ) ₂ obtained above. As shown in FIG. 17, in the thermogravimetric analyzer, the vapor pressure was measured by TGA / DSC 3+ manufactured by METTLER TOLEDO. As a result, the vapor pressure of Et ₂ Ge— (Co (CO) ₄ ) ₂ at 90 ° C. was about 1.1 Torr. The measurement conditions were a nitrogen gas flow rate of 220 SCCM, a heating rate of 10 ° C./min, and the vapor pressure was determined by isothermal thermogravimetry.

Example _{26: Et 2 Ge- (Co (} CO) 4) 2 thermal CVD
Et ₂ Ge— (Co (CO) ₄ ) ₂ was used as the Ge-containing Co film forming material, and a Ge-containing Co film was formed on the substrate by a thermal CVD method under the following conditions without using an additive gas. The analysis result by XPS of the film thus obtained is shown in FIG. 18, and the analysis result by SEM is shown in FIG. 19 and FIG.
<Film formation conditions>
Apparatus used: An apparatus having the configuration shown in FIG. 2 was used. A shower head for supplying the Ge-containing Co film forming material and the carrier gas introduced into the chamber 102 to the substrate 103 held by the substrate holder in the chamber 102 is attached to the chamber (102) in FIG. ing. The film formation temperature was controlled by controlling the temperature of the substrate holder.
Ge-containing Co film forming material: Et ₂ Ge— (Co (CO) ₄ ) ₂
・ Substrate: SiO ₂ (cleaned with HF)
-Film formation temperature: 160 ° C
・ In-chamber pressure: 1 Torr
-Ge-containing Co film forming material container temperature: 63 ° C
-Carrier gas: Argon gas-Carrier gas flow rate: 10 SCCM
-Film formation time: 60 minutes-XPS: K-Alpha manufactured by Thermo Scientific
-SEM: S-5200 manufactured by Hitachi, Ltd.
Resistance meter: Keithley source meter 4ZA4
AFM: MFP-3D manufactured by Asylum Research

FIG. 18 shows the result of XPS analysis of the Ge-containing Co film obtained above. As shown in FIG. 18, from the analysis result by XPS, Co atoms were detected in the bulk of the obtained Ge-containing Co film at a ratio of about 45% and Ge atoms were about 55%. It can be seen that a Ge-rich CoGe film, which is a Co film, is formed. It can be said that a Ge-containing Co film with less carbon impurities was obtained because the carbon content in the bulk of the Ge-containing Co film obtained with Et ₂ Ge— (Co (CO) ₄ ) ₂ was less than 1%.

  FIG. 19 shows the SEM analysis result of the Ge-containing Co film obtained above. As shown in FIG. 19, the average film thickness of the obtained Ge-containing Co film was about 17.4 nm. Since the film formation time was 60 minutes, the film formation rate was 0.29 nm / min. The resulting Ge-containing Co film had a bulk resistance value of 232.5 μΩ · cm.

  FIG. 20 is an SEM analysis result (enlarged view) of the Ge-containing Co film obtained above. As shown in FIG. 20, the obtained Ge-containing Co film was a uniform and conformal film.

Example _{27: Et 2 Ge- (Co (} CO) 4) 2 thermal CVD
Et ₂ Ge— (Co (CO) ₄ ) ₂ was used as the Ge-containing Co film forming material, and a Ge-containing Co film was formed on the substrate by a thermal CVD method under the following conditions without using an additive gas. The experimental conditions are the same as in Example 26 except that the film formation temperature is 200 ° C. The results of XPS analysis of the film thus obtained are shown in FIG. 21, and the results of SEM analysis are shown in FIG. 22 and FIG.

FIG. 21 shows the XPS analysis result of the Ge-containing Co film obtained above. As shown in FIG. 21, from the analysis result by XPS, Co atoms were detected in the bulk of the obtained Ge-containing Co film at a ratio of about 50% and Ge atoms were about 50%. It can be seen that a Co film is formed. It can be said that a Ge-containing Co film with less carbon impurities was obtained because the carbon content in the bulk of the Ge-containing Co film obtained with Et ₂ Ge— (Co (CO) ₄ ) ₂ was less than 1%.

FIG. 22 shows the SEM analysis result of the Ge-containing Co film obtained above. As shown in FIG. 22, the average film thickness of the obtained Ge-containing Co film was about 50.3 nm. Since the film formation time was 60 minutes, the film formation rate was 0.84 nm / min. The resulting Ge-containing Co film had a bulk resistance value of 243.58 μΩ · cm.

  FIG. 23 is an SEM analysis result (enlarged view) of the Ge-containing Co film obtained above. As shown in FIG. 23, the obtained Ge-containing Co film was a uniform and conformal film.

Example _{28: Et 2 Ge- (Co (} CO) 4) 2 thermal CVD
Et ₂ Ge— (Co (CO) ₄ ) ₂ was used as the Ge-containing Co film forming material, and a Ge-containing Co film was formed on the substrate by a thermal CVD method under the following conditions without using an additive gas. The experimental conditions are the same as in Example 26 except that the film formation temperature is 220 ° C. The results of XPS analysis of the film thus obtained are shown in FIG. 24, and the results of SEM analysis are shown in FIGS.

FIG. 24 shows the XPS analysis result of the Ge-containing Co film obtained above. As shown in FIG. 24, from the analysis result by XPS, Co atoms were detected in the bulk of the obtained Ge-containing Co film in an abundance ratio of about 50% and Ge atoms about 50%. It can be seen that a Co film is formed. It can be said that a Ge-containing Co film with less carbon impurities was obtained because the carbon content in the bulk of the Ge-containing Co film obtained with Et ₂ Ge— (Co (CO) ₄ ) ₂ was less than 1%.

  FIG. 25 shows the SEM analysis result of the Ge-containing Co film obtained above. As shown in FIG. 25, the average film thickness of the obtained Ge-containing Co film was about 18.3 nm. Since the film formation time was 60 minutes, the film formation rate was 0.31 nm / min. The resulting Ge-containing Co film had a bulk resistance value of 141.8 μΩ · cm.

  FIG. 26 is an SEM analysis result (enlarged view) of the Ge-containing Co film obtained above. As shown in FIG. 26, the obtained Ge-containing Co film was a uniform and conformal film.

As described above, as shown in Examples 26, 27, and 28, a Ge-containing Co film could be formed using Et ₂ Ge— (Co (CO) ₄ ) ₂ as a film forming material. The content ratio of Ge atoms and Co atoms in the formed Ge-containing Co film was 40% or more and less than 60%.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 10 ... Substrate, 12 ... Recess, 20 ... Ge-containing Co film, 101 ... CVD apparatus, 102 ... Chamber, 103 ... Substrate, 201 ... Ge-containing Co film forming material supply pipe, 202 ... Additive gas supply pipe, 204 ... Ge-containing Co film forming material flow rate adjusting mechanism, 205 ... added gas flow rate adjusting mechanism, 301, 302 ... added gas container, 304 ... Ge-containing Co film forming material container, 401 ... carrier gas supply pipe, 405 ... APC valve

Claims (22)

A material for forming a Ge-containing Co film for manufacturing a semiconductor device,
A Ge-containing Co film-forming material, which is a compound represented by the following general formula (1) or the following general formula (2).
R ¹ R ² R ³ Ge—Co (CO) ₄ (1)
(In the general formula (1), R ¹ , R ² and R ³ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group. Non-aromatic hydrocarbon groups exclude cross-linked non-aromatic hydrocarbon groups, and halogenated non-aromatic hydrocarbon groups exclude cross-linked halogenated non-aromatic hydrocarbon groups.)
Co (CO) ₄ R ⁴ R ⁵ Ge—Co (CO) ₄ (2)
(In the general formula (2), R ⁴ and R ⁵ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group. (The hydrocarbon group excludes a crosslinked non-aromatic hydrocarbon group, and the halogenated non-aromatic hydrocarbon group excludes a crosslinked halogenated non-aromatic hydrocarbon group.) Compound represented by the general formula (1) or the general formula (2) _{^{is, NMe 3, NEt 3, N}} i Pr 3, NMeEt 2, NC 5 H 5, OC 4 H 8, Me 2 O, Et 2 The Ge-containing Co film-forming material according to claim 1, further comprising one or two neutral adduct ligands selected from the group consisting of O, Et ₂ S, ⁿ Pr ₂ S, and ⁿ Bu ₂ S. The compound represented by the general formula (1), wherein R ¹ , R ² and R ³ are each independently a hydrocarbon group or a halogenated hydrocarbon group having 1 to 4 carbon atoms. The Ge-containing Co film forming material according to claim 1 or 2. The compound represented by the general formula (1) _{is Et 3 Ge-Co (CO)} 4, Ge -containing Co film forming material according to claim 3. The compound represented by the general formula (2), wherein R ⁴ and R ⁵ are each independently a hydrocarbon group or a halogenated hydrocarbon group having 1 to 4 carbon atoms. Item 3. A Ge-containing Co film forming material according to Item 2. The Ge-containing Co film forming material according to claim 5, wherein the compound represented by the general formula (2) is Co (CO) ₄ Et ₂ Ge—Co (CO) ₄ .   A Ge-containing Co film formed by depositing the Ge-containing Co film forming material according to any one of claims 1 to 6 by a CVD method or an ALD method.   The Ge-containing Co film according to claim 7, wherein a composition ratio of Ge and Co is Ge: Co = 1: 99 to 99: 1.   The Ge-containing Co film according to claim 7 or 8, wherein the film thickness is 0.1 nm or more and 400 nm or less.   10. The Ge-containing Co film according to claim 7, wherein the bulk resistance value is 6 μΩ · cm or more and 300 μΩ · cm or less.   The Ge-containing Co film according to any one of claims 7 to 10, wherein the surface roughness (RMS) is 0.01 nm or more and 15 nm or less.   When the film is formed on a substrate having at least one recess, the ratio of the film thickness of the inner wall surface or the inner bottom surface of the recess to the film thickness of the surface of the substrate is 0.2 or more and 1.1 or less. The Ge-containing Co film according to any one of claims 7 to 11.   The Ge-containing Co film according to any one of claims 7 to 12, wherein a minimum continuous film thickness is 1 nm or more and 5 nm or less.   The Ge-containing Co film according to any one of claims 7 to 13, which is a low resistance contact layer formed in a source / drain region of a FinFET transistor disposed on a Si or Ge substrate.   The Ge-containing Co film according to any one of claims 7 to 13, which is a barrier layer of a wiring layer.   A semiconductor device comprising the Ge-containing Co film according to any one of claims 7 to 15.   An electronic apparatus comprising the semiconductor device according to claim 15. A method of forming a Ge-containing Co film,
A first step of introducing a substrate into the chamber;
A Ge-containing Co film forming material represented by the following general formula (1) or the following general formula (2) is introduced into a chamber in which the substrate is disposed while controlling the amount of the Ge-containing Co film forming material introduced. Two processes,
A third step of depositing at least a part of the Ge-containing Co film forming material on the substrate so as to form the Ge-containing Co film;
Method for forming a Ge-containing Co film containing
R ¹ R ² R ³ Ge—Co (CO) ₄ (1)
(In the general formula (1), R ¹ , R ² and R ³ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group or a halogenated non-aromatic hydrocarbon group. Non-aromatic hydrocarbon groups exclude cross-linked non-aromatic hydrocarbon groups, and halogenated non-aromatic hydrocarbon groups exclude cross-linked halogenated non-aromatic hydrocarbon groups.)
Co (CO) ₄ R ⁵ R ⁶ Ge—Co (CO) ₄ (2)
(In the general formula (2), R ⁵ and R ⁶ are each independently hydrogen, a non-aromatic hydrocarbon group, a halogeno group, or a halogenated non-aromatic hydrocarbon group. (The hydrocarbon group excludes a crosslinked non-aromatic hydrocarbon group, and the halogenated non-aromatic hydrocarbon group excludes a crosslinked halogenated non-aromatic hydrocarbon group.)   The third step is chemical vapor deposition (CVD), atomic layer deposition (ALD), plasma enhanced chemical vapor deposition (PECVD), plasma enhanced atomic layer deposition (PEALD), pulsed chemical vapor deposition (PCVD), low pressure chemical vapor deposition ( 19. The method of claim 18, selected from the group consisting of LPCVD), low pressure chemical vapor deposition (SACVD), atmospheric pressure chemical vapor deposition (APCVD), spatial ALD, radical assisted deposition, supercritical fluid deposition, and combinations thereof. A method for forming a Ge-containing Co film. Fourth step of introducing at least one additive gas selected from the group consisting of ammonia, hydrogen, inert gas, alcohol, amino alcohol, amine, GeH ₄ , Ge ₂ H ₆ and combinations thereof into the chamber. The method for forming a Ge-containing Co film according to claim 18 or 19, further comprising: 21. The method of forming a Ge-containing Co film according to claim 18, wherein the third step is performed at a temperature of 0 ° C. or higher and 350 ° C. or lower.   The method for forming a Ge-containing Co film according to any one of claims 18 to 21, wherein the pressure in the chamber is 0.06 Torr or more and atmospheric pressure or less.