KR20090090222A - Novel precursors for deposition of tellurium thin film and deposition method using the same - Google Patents

Abstract

A precursor compound for deposition of tellurium thin film is provided to ensure volatility, thermal stability and deposition performance which are suitable as a precursor compound for manufacturing a tellurium thin film. A precursor compound for deposition of tellurium thin film has a structure represented by chemical formula 1. In chemical formula 1, R1 and R2 are independently hydrogen or linear or branched (C1-C7) alkyl, however, R1 and R2 are not hydrogen at the same time. A method for manufacturing the tellurium thin film comprises the steps of: introducing a reaction substrate inside a chamber; injecting the precursor compound for deposition of tellurium thin film and absorbing it on the substrate; purging the precursor compound for deposition of tellurium thin film remaining in the chamber and by-products; forming the tellurium thin film by supplying the activating gas to the chamber; and purging residual reactive gas and reaction by-products within the chamber.

Description

Novel precursors for deposition of tellurium thin film and deposition method using the same

The present invention relates to a novel precursor compound for tellurium thin film deposition and a method for depositing tellurium thin film using the same, and using the novel organometallic precursor compound represented by the following Chemical Formula 1 and the precursor compound, the step coverage is excellent and the thin film It relates to a method for producing a tellurium thin film free of impurities.

[Formula 1]

[Wherein, R ₁ and R ₂ are each independently hydrogen or straight or branched chain (C ₁ -C 7) alkyl, provided that R ₁ and R ₂ are not simultaneously hydrogen.]

The semiconductor memory device may be classified into a volatile memory device and a nonvolatile memory device according to whether data is stored after the power is turned off. In general, nonvolatile memory devices, which are stored in a state where the stored information is not erased even when the power is cut off, are showing rapid technological developments along with increasing demand for portable personal terminals. Phase change memory devices are being researched as next generation memory devices that can replace flash memory devices as nonvolatile memory devices. The phase change memory device includes a phase change material maintained in one of a crystalline state and an amorphous state. The phase change material may change to another state by heating and cooling. Phase change materials have low resistance in the crystalline state and high resistance in the amorphous state.

Tellurium (Te) is used as a main component of the GST (germanium) -Sb (antimony) -Te (tellurium) alloy which is used as a phase change material of phase change memory and an optical recording medium. Metal tellurium is important in the semiconductor art, for example, in the manufacture of infrared detector cadmium mercury telluride (CMT) and in photosensitive switches, respectively. Frequently, these metals or, in particular, these compounds, such as CMT, are volatile compounds of the component metals, which include the vapor phase co-degradation of the volatile compounds of the component metals (in the case of tellurium, which is the most common dialkyl compound). Deposited on the substrate by a process of Metal-Organic Vapor Phase Epitaxy (MOVPE). Dialkyl compounds, in addition to volatiles, have the advantage that they can be easily purified by forming adducts which can be readily degraded to form pure dialkyl compounds as described in the literature. See GB-A-850955 and PCT / GB88 / 01062]. Dialkyl ditellides are not only useful as precursors of MOVPE enrichment but can also be used to prepare asymmetric dialkyl compounds (GB 8913799. 6).

In the past, sputtering was used to manufacture a tellurium thin film. Sputtering is a method of colliding accelerated particles with a solid surface to attach atoms protruding into space by exchanging momentum to a substrate. Therefore, the above method is difficult to apply to the trench structure of the highly integrated semiconductor device having a complicated three-dimensional structure due to its characteristics. Therefore, the chemical vapor deposition method is also a step according to the aspect ratio of the substrate structure or pattern for depositing the thin film by vaporizing the compound to be deposited into the reaction chamber to obtain a thin film of the desired material using the chemical reaction It is a deposition method that is used to obtain a high degree of integration with Atomic layer deposition (ALD) due to its excellent step coverage. The atomic layer deposition method is a method of depositing an atomic layer on a semiconductor substrate by sequentially repeating a process of injecting a reactant into a chamber and removing residual reactants and by-products. The atomic layer deposition method is a deposition method using a chemical reaction like the CVD method, but the CVD method is injected in a chamber by injecting each gas at the same time, while the ALD method is injected in the form of pulses by one type of gas, Are distinguished.

In detail, a method of manufacturing a tellurium thin film using a chemical vapor deposition method or an atomic layer deposition method is conventionally used as a tellurium raw material Te ( ⁱ Pr) ₂ , Te ( ^t Bu) ₂ and the like.

However, Te ( ⁱ Pr) ₂ and Te ( ^t Bu) ₂ have a slow deposition rate of tellurium when atomic layer deposition is used, and some incompletely decomposed compounds are difficult to exist independently due to breakage of chemical bonds. There was a problem that a lot of impurities remain in the rulium thin film.

The present invention is to solve the above problems, to provide a novel precursor compound for tellurium thin film deposition, a method for producing a tellurium thin film having excellent step coverage and no impurities in the thin film using the precursor compound. The purpose is to provide.

The present invention relates to a novel tellurium thin film precursor compound represented by the following Chemical Formula 1, which is designed to fully cover the advantages of the existing precursors for depositing the tellurium thin film and to make up the most disadvantages, and also the precursor compound. The present invention relates to a method for producing a tellurium thin film having excellent step coverage and no impurities in a thin film.

[Formula 1]

[Wherein, R ₁ and R ₂ are each independently hydrogen or straight or branched chain (C ₁ -C 7) alkyl, provided that R ₁ and R ₂ are not simultaneously hydrogen.]

R ₁ and R ₂ of the compound of Formula 1 are independently of each other hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, i-pentyl, n -Hexyl or n-heptyl.

The diamino tellurium derivative according to the present invention may be specifically exemplified as a compound selected from the following Chemical Formulas 2 to 5, but the following compounds are not intended to limit the present invention.

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

Starting material for preparing the precursor compound is a known compound, tellurium tetrachloride (Tellurium tetrachloride, TeCl ₄ ) is used.

After reacting the organometallic reagent with the dialkylamine derivative in a nitrogen atmosphere, tellurium tetrachloride is added thereto, followed by stirring and vacuum purification to prepare a tellurium thin film precursor compound according to the present invention. Examples of the organometallic reagent include n -butyllithium, sec -butyllithium, and tert -butyllithium. Of these, n -butyllithium is preferable.

In addition, the present invention provides a method for producing a tellurium thin film using the precursor compound for tellurium thin film deposition. In preparing a tellurium thin film using the tellurium thin film precursor compound, an inert gas such as argon or helium is used as a transport gas.

A method of manufacturing a tellurium thin film from a precursor compound for tellurium thin film deposition by using an atomic layer deposition method (ALD) includes the following steps.

(a) introducing a reaction substrate into the chamber;

(b) injecting the precursor compound for tellurium thin film deposition according to the present invention into the chamber and adsorbing it on a substrate;

(c) purging the precursor compound and by-products for depositing the tellurium thin film remaining in the chamber;

(d) supplying an activation gas to the chamber to form a tellurium thin film;

(e) purging the residual reaction gas and reaction byproducts in the chamber.

The manufacturing method according to the present invention includes adsorbing the tellurium precursor compound on the reaction substrate as an atomic layer deposition method, and supplying an activation gas to form a tellurium mono-layer (d). In addition, the purge step (c, e) in the middle for the complete atomic layer deposition is characterized by a uniform deposition. The activation gas may be supplied by a method of injecting hydrogen gas or ammonia into the chamber and applying a high frequency (RF) directly to the chamber to form a hydrogen (H ₂ ) plasma or ammonia (NH ₃ ) plasma in the chamber. It may also be supplied by a remote plasma which forms a plasma externally and guides it into the chamber. The activation gas may react with and remove an organic component of the adsorbed tellurium precursor compound to deposit a pure tellurium thin film on the substrate. In addition, the steps (b) to (e) are referred to as one cycle, and after the step (e), the steps (b) to (e) are repeated one or more times to repeat the tellurium monolayer. A deposited multilayer tellurium thin film is prepared.

The method for producing a tellurium thin film from a precursor compound for tellurium thin film deposition by using chemical vapor deposition (CVD) is characterized in that it comprises the following steps.

(f) introducing a reaction substrate into the chamber;

(g) injecting the tellurium thin film deposition precursor compound and a transfer gas into the chamber by adsorbing and depositing the same on a substrate.

(h) purging residual byproducts and gases in the chamber.

The manufacturing method according to the present invention is a chemical vapor deposition method in which the tellurium precursor compound is injected into a chamber by a transfer gas on a reaction substrate to cause a chemical reaction on the surface of the substrate, and the compound formed on the substrate is adsorbed onto the substrate by diffusion. (g) and the purge step (h) of the residual gas and by-products, it is characterized in that the uniform deposition. In addition, the (g) ~ (h) step is made at the same time to produce a thin film by forming and growing a tellurium thin film. In order to form and grow the tellurium thin film, it is preferable to continuously perform the above steps (g) to (h) for 10 minutes or more.

As described above, the novel precursor compound for tellurium thin film deposition according to the present invention has suitable volatility, thermal stability and deposition performance as a precursor compound for producing a tellurium thin film, and is formed by using the precursor compound The rulium thin film can be said to be widely used in the manufacture of highly integrated semiconductor devices and related industries by solving the impurities and step coverage problems of the conventional tellurium precursor compound.

Hereinafter, embodiments of the present invention will be described in more detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, only the embodiments are to make the disclosure of the present invention complete, complete the scope of the invention to those skilled in the art It is provided to inform you.

Hereinafter, the preparation method of the precursor compound and the ligand for synthesizing the precursor compound of the present invention will be described in more detail with reference to the following preparation examples.

[ Production Example  One] Diethylmethylaminotellurium  [Te (N ( C ₂ H ₅ ) ( CH ₃ )) ₂ ] Manufacture

[화학식 2]

[Formula 2]

Slowly add 42.3 ml of ethylmethylamine to 128.6 ml of n-BuLi (1.6 M in Hexane) cooled under nitrogen atmosphere and stir for 5 hours to form LiNEtMe solution, and slowly add TeCl ₄ (33.15g) to 5 hours at room temperature After stirring, LiCl as a by-product was filtered and the solvent was removed using a vacuum. After the solvent was removed, the remaining dark brown liquid was first purified by distillation at 28 ° C. while maintaining a vacuum (260 mTorr) state, and the product obtained by the first purification was distilled again while maintaining a vacuum (300 mTorr) state at 25 ° C. Secondary purification was performed to obtain 6 g (20%) of Te (N (C ₂ H ₅ ) (CH ₃ )) ₂ [Chemical Formula 2] with high purity as the title compound. The results of ¹ H-NMR and FTIR are as follows.

¹ H-NMR (400 MHz C ₆ D ₆ ): δ (ppm) = 3.41 (Te- CH ₃ ), 3.31 (Te- CH ₂ -CH ₃ ), 1.02 (Te-CH ₂ -CH ₃ ).

FTIR (cm ^-1 ): 2964.08 (m), 2834.49 (m), 2782.58 (m), 1440.31 (m), 1409.22 (m), 1369.50 (m), 1345.11 (m), 1259.65 (w), 1196.46 (m) ), 1171.77 (s), 1050.19 (s), 1018.07 (s), 981.10 (vs), 862.68 (vs), 797.95 (m)

[ Example  1] using chemical vapor deposition Tellurium  Manufacture of thin film

The method of preparing a tellurium thin film using the precursor compound Te (N (C ₂ H ₅ ) (CH ₃ )) ₂ prepared in Preparation Example 1 of the present invention will be described in more detail.

A silicon wafer, which is a reactor plate, is introduced into the chamber, the substrate temperature is 250 ° C, and the temperature of Te (N (C ₂ H ₅ ) (CH ₃ )) _{2 in} the stainless steel bubbler vessel is 30 ° C. Shall be. Then, Te (EMA) ₂ is adsorbed and decomposed with Te (N (C ₂ H ₅ ) (CH ₃ )) ₂ into thermal energy on the injection substrate into the reaction chamber using argon gas as a transport gas. Residual by-products and gases are purged using argon gas and vacuum pump to remove residual gas or non-adsorbed Te (N (C ₂ H ₅ ) (CH ₃ )) ₂ from the chamber. A rulium thin film is prepared. The process was carried out for 10 minutes to confirm that a tellurium thin film was formed. The thickness of the formed tellurium thin film may be adjusted by forming the thin film over time according to a desired characteristic of the process.

The resulting tellurium thin film had almost no impurity generation and had excellent step coverage characteristics.

[ Example  2] Atomic layer  Using vapor deposition Tellurium  Manufacture of thin film

The method of preparing a tellurium thin film using the precursor compound Te (N (C ₂ H ₅ ) (CH ₃ )) ₂ prepared in Preparation Example 1 of the present invention will be described in more detail.

A silicon wafer serving as a reactor plate was introduced into the chamber, the substrate temperature was set to 180 ° C, and the temperature of Te (N (C ₂ H ₅ ) (CH ₃ )) _{2 in} the stainless steel bubbler container was set to 30 ° C. Shall be. Thereafter, Te (N (C ₂ H ₅ ) (CH ₃ )) ₂ is injected into the reaction chamber using argon gas as a transport gas to adsorb the tellurium compound to the substrate. Then, purge with argon gas and vacuum pump for 6 seconds to remove residual gas or non-adsorbed Te (N (C ₂ H ₅ ) (CH ₃ )) ₂ inside the chamber. Thereafter, a hydrogen plasma is supplied for 4 seconds to react with the precursor adsorbed on the silicon wafer to form a tellurium thin film. In addition, by using the argon gas and vacuum pump for 6 seconds to purge the decomposed residue once again to produce a tellurium thin film. Through this process, a tellurium mono-layer thin film having a thickness of 0.6 mW per cycle was formed. The thickness of the formed tellurium thin film may be adjusted by repeatedly performing the cycle according to desired characteristics to form a multilayer film.

The resulting tellurium thin film had almost no impurity generation and had excellent step coverage characteristics.

1 is a schematic view of an atomic layer deposition reaction apparatus according to the present invention,

2 is a flowchart of an atomic layer deposition process according to the present invention,

3 is a schematic view of a chemical vapor deposition reaction apparatus according to the present invention,

4 is a chemical vapor deposition process flow chart according to the present invention,

<Explanation of symbols for the main parts of the drawings>

10 reactor 20 heater 30 substrate

40: RF Power 50: Bubbler 55: gas injection tube

60: transfer gas cylinder 70: reaction gas cylinder 80: pump

110: reactor 120: heater 130: substrate

140: bubbler 145: raw material injection pipe 150: transfer gas cylinder

160: pump

Claims (7)

A precursor compound for tellurium thin film deposition represented by the following formula (1). [Formula 1]

[Wherein, R ₁ and R ₂ are each independently hydrogen or straight or branched chain (C ₁ -C 7) alkyl, provided that R ₁ and R ₂ are not simultaneously hydrogen.] The method of claim 1, R ₁ to R ₄ are each independently hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, i-pentyl, n-hexyl or n- Diamino tellurium derivative, characterized in that heptyl. The method of claim 2, Diamino tellurium derivatives, characterized in that selected from the formula (2) to (5). [Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

(a) introducing a reaction substrate into the chamber; (b) injecting the precursor compound for depositing tellurium thin film according to any one of claims 1 to 3 into the chamber and adsorbing it on a substrate; (c) purging the precursor compound and by-products for depositing the tellurium thin film remaining in the chamber; (d) supplying an activation gas to the chamber to form a tellurium thin film; And (e) purging the residual reaction gas and reaction by-products in the chamber. The method of claim 4, wherein After the step (e), repeating steps (b) to (e) one or more times to form a tellurium thin film, characterized in that to form a multi-layer tellurium film. The method of claim 4, wherein The activation gas is a method of producing a tellurium thin film, characterized in that supplied by hydrogen plasma or ammonia plasma. (f) introducing a reaction substrate into the chamber; (g) injecting the precursor compound for tellurium thin film deposition according to any one of claims 1 to 3 and a transport gas into the chamber to be adsorbed onto the substrate and deposited; And (h) purging the residual by-products and gases in the chamber.

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