JPH05182913A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a method for manufacturing a semiconductor device in which mixture of C, O, etc., in an amorphous silicon film can be eliminated, crystallinity of an obtained polycrystalline silicon film is improved, and a resistance can be reduced. CONSTITUTION:The method for manufacturing a semiconductor device comprises the steps of forming a hydrogen-containing amorphous silicon film by reacting silane series gas with impurity-containing gas with hydrogen gas as base gas by a chemical vapor growing method, and then forming a polycrystalline silicon film by crystallizing the amorphous silicon film by heat treating it in an inert gas atmosphere.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and can be applied to a method for manufacturing a bipolar transistor, a dynamic random memory, a TFT, etc.
In particular, the present invention relates to a semiconductor device manufacturing method capable of improving the crystallinity of a polycrystalline silicon film formed by crystallizing an amorphous silicon film.

In recent years, device manufacturing requires thinning, low temperature, and cost reduction. With this demand, a method of doping impurities into polysilicon can be achieved without thermal diffusion or ion implantation. There is a demand for ways that can be done. In particular, there is a demand for a method of manufacturing a semiconductor device that can improve the crystallinity of a polycrystalline silicon film formed by crystallizing an amorphous silicon film.

[0003]

2. Description of the Related Art Regarding the conventional method for forming a polycrystalline silicon film, first, a hydrogen gas and a silane-based gas are reacted in an inert gas atmosphere by a CVD method to form an amorphous silicon film, and then an inert gas is formed. The amorphous silicon film is crystallized by heat treatment in an atmosphere to form a polycrystalline silicon film. Thus, when deposited in an amorphous state, undecomposed hydrogen of the silicon source gas is taken into the film, and when the taken amorphous silicon film is annealed, hydrogen in the film is released and crystallization occurs.

[0004]

The above-mentioned conventional method for manufacturing a semiconductor device has the advantage that it is superior in terms of thinning, lowering of temperature and cost compared to the case of using thermal diffusion or ion implantation. When a hydrogen gas and a silane-based gas are reacted in an inert gas atmosphere by a CVD method to form an amorphous silicon film, C, O, etc. in the chamber are mixed in the amorphous silicon film as shown in FIG. easy. Then, when the amorphous silicon film is crystallized by heat treatment in an inert gas atmosphere to form a polycrystalline silicon film, as shown in FIG. 2B, even if heat treatment is performed, C and O mixed in the film are mixed. Etc. could not be skipped and removed. Therefore, the crystallinity of the obtained polycrystalline silicon film is poor, and there is a problem in terms of resistance reduction.

Therefore, in the present invention, it is possible to prevent C, O, etc. from being mixed into the amorphous silicon film,
It is an object of the present invention to provide a method for manufacturing a semiconductor device, which can improve the crystallinity of the obtained polycrystalline silicon film and reduce the resistance.

[0006]

In order to achieve the above object, a method of manufacturing a semiconductor device according to a first aspect of the present invention comprises reacting a silane-based gas with an impurity-containing gas using hydrogen gas as a base gas by chemical vapor deposition. And forming a hydrogen-containing amorphous silicon film by heat treatment in an inert gas atmosphere to crystallize the hydrogen-containing amorphous silicon film to form a polycrystalline silicon film.

The silane-based gas according to the first aspect of the invention includes monosilane gas, disilane gas, trisilane gas and the like, and the impurity-containing gas includes gases containing P, B, As and the like. The preferable substrate temperature for depositing the hydrogen-containing amorphous silicon film is 550 ° C. or lower, and in this case, the amorphous silicon film can be deposited. It should be noted that, when the temperature exceeds 550 ° C, the state becomes the transition region, and when the temperature exceeds 590 ° C, the state becomes polycrystalline.

In the invention of claim 1, the polycrystalline silicon film can be preferably applied to an emitter electrode of a bipolar transistor or a capacitor electrode or wiring of a DRAM. In the invention of claims 1 and 2, the deposition pressure when forming the hydrogen-containing amorphous silicon film is preferably 50 Torr or more, and in this case, the coverage can be formed with better coverage than when it is less than 50 Torr.

In the invention of claims 1 to 3, the manufacturing apparatus for forming the hydrogen-containing amorphous silicon film is a single-wafer chemical vapor deposition apparatus, and a reactor of the single-wafer chemical vapor deposition apparatus. The inside is preferably surface-treated with graphite or silicon carbide coated with silicon carbide, and in this case, the inside of the chamber is S
It is possible to make particles less likely to be generated than when exposed by US or quartz.

In order to achieve the above object, a method for manufacturing a semiconductor device according to a fifth aspect of the present invention is a step of forming a hydrogen-containing amorphous silicon film by reacting a silane-based gas with hydrogen gas as a base gas by a chemical vapor deposition method. And then heat-treating in an inert gas atmosphere to crystallize the hydrogen-containing amorphous silicon film to form a polycrystalline silicon film.

The invention according to claim 5 can be preferably applied when forming a TFT.

[0012]

FIG. 1 is a diagram for explaining the principle of the present invention. In this example
Is H₂Impurity with silane-based gas using gas as base gas
Since the substance-containing gas was reacted, C and O in the chamber
Base gas H₂O + H by gas₂→ H₂O, C +
2H₂→ CH_FourLike H ₂O gas, CH_FourRemove as gas
Amorphous silicon film that can be removed
A natural oxide film (SiO) containing C that is likely to occur on the surface₂Membrane)
H, a base gas with strong originality₂Gas removal
You can Therefore, as shown in FIG.
The long bond can be terminated with H. That
In this state, heat treatment for crystallization is performed.
Therefore, as shown in FIG. 1 (b), hydrogen-containing amorphous silicon
H can be desorbed from the mixture, and C, O, etc. are mixed in.
Good crystallinity and good surface morphology
An excellent polycrystalline silicon film can be obtained.

[0013]

EXAMPLES Examples of the present invention will be described below. Here, a method for forming a polycrystalline silicon film forming an emitter electrode of a bipolar transistor will be specifically described. First, using a single-wafer CVD apparatus, H
Film thickness by reacting ₂ gas, Si ₂ H ₆ gas and PH ₃ gas
A hydrogen containing amorphous silicon film of about 100 nm is formed. The growth conditions at this time are Si ₂ H ₆ gas 100 sccm, PH
₃ gas 20% / H ₂ gas 100sccm, H ₂ gas 10sccm, pressure
100 Torr, substrate temperature is 500 ℃.

Then, the hydrogen-containing amorphous silicon film is crystallized by performing a heat treatment at 750 ° C. for about 30 minutes in an Ar gas atmosphere to form a polycrystalline silicon film to be an emitter electrode. As described above, in this embodiment, since H ₂ gas was used as the base gas to react the Si ₂ H ₆ gas and the PH ₃ gas, C and O in the chamber were O + H ₂ → H ₂ by the H ₂ gas of the base gas. O, C + 2H ₂ → H as CH _4
2 O gas or CH ₄ gas can be removed, and a natural oxide film (SiO ₂ film) containing C, which easily occurs on the surface of an amorphous silicon film, can be removed by H ₂ gas, which is a highly reducing base gas. it can. For this reason, as shown in FIG.
Can be terminated with. Since heat treatment for crystallization is performed in this state, as shown in FIG. 1B, H can be desorbed from the hydrogen-containing amorphous silicon, and a crystal in which C, O, etc. are not mixed. It is possible to obtain a polycrystalline silicon film having good properties and good surface morphology.

Further, the obtained polycrystalline silicon film is
Configured by using it as the emitter electrode of the Ipolar transistor,
When the characteristics of the bipolar transistor were measured, h_FE 1
00, V_EB7.0 V, V_CB39V, V_CE 5.0V and good without problems
Good transistor characteristics could be obtained. The above
In the embodiment, the base gas is H₂When using gas
However, in the present invention, H₂In addition to gas
Strongly reducing Si₃H₈When introducing a small amount of gas
It may be. In this case Si₃H₈Do not deposit gas
The natural oxide film, C, O, etc. are effective by flowing a small amount
It is preferable because it can be removed selectively. Also, in the above embodiment
Is the source gas of Si₂H₆Gas was used, but Si₃H ₈
Gas may also be used, in which case the surface treatment during deposition
The amount of gas may be adjusted appropriately at any time.

[0016]

According to the present invention, it is possible to prevent C, O, etc. from being mixed into the amorphous silicon film and to improve the crystallinity of the obtained polycrystalline silicon film. is there.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram illustrating a problem of a conventional example.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location H01L 29/784 // H01L 21/28 301 A 7738-4M 21/3205

Claims (6)

[Claims] 1. A step of forming a hydrogen-containing amorphous silicon film by reacting a silane-based gas with an impurity-containing gas using hydrogen gas as a base gas by a chemical vapor deposition method, and then performing heat treatment in an inert gas atmosphere. And a step of crystallizing the hydrogen-containing amorphous silicon film to form a polycrystalline silicon film. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the polycrystalline silicon film is an emitter electrode of a bipolar transistor or a capacitor electrode or wiring of a dynamic random access memory. 3. The method for manufacturing a semiconductor device according to claim 1, wherein a deposition pressure when forming the hydrogen-containing amorphous silicon film is 50 Torr or more. 4. The manufacturing apparatus for forming the hydrogen-containing amorphous silicon film is a single-wafer chemical vapor deposition apparatus, and the inside of the reactor of the single-wafer chemical vapor deposition apparatus is graphite coated with silicon carbide or 2. The surface-treated with silicon carbide.
4. A method for manufacturing a semiconductor device according to any one of 3 to 3. 5. A step of forming a hydrogen-containing amorphous silicon film by reacting a silane-based gas with hydrogen gas as a base gas by a chemical vapor deposition method, and then heat-treating the same in an inert gas atmosphere. A method of manufacturing a semiconductor device, comprising the step of crystallizing an amorphous silicon film to form a polycrystalline silicon film. 6. A TFT using the polycrystalline silicon film
(Thin Film Transistor) is formed, The manufacturing method of the semiconductor device of Claim 5 characterized by the above-mentioned.