JPS6190422A - Device for photochemical vapor deposition - Google Patents

Abstract

PURPOSE:To contrive the improvement in a depositing velocity and yield of the deposited films by providing a means for making the density of a material gas in the vicinity of the position for supporting a substrate in a reactor higher than that in other positions. CONSTITUTION:A device for photochemical vapor deposition for depositing a film on a substrate supported in the reactor by utilizing a photochemical reaction which is provided with a reactor, a means for introducing a material gas into the reactor, and a means for irradiating the material gas with a high- energy beam wherein a gas is introduced into a reactor 11 from a small hole 23 of an introducing pipe 22 while cooling a material supporting means 25 by circulating a cooling medium, e.g., water in a cavity 26 and heating the reactor 11 by a heating means 21. Consequently, a temperature in the vicinity of the substrate (A) becomes lower than that in the vicinity of the container 11 so that a density of the material gas in the container 11 becomes higher than the vicinity of the substrate (A). Accordingly, a photochemical reaction is carried out mainly right above the substrate (A) by irradiation with a beam B and a deposition on the substrate (A) is made effectively, thereby improving a yield of the deposited films.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical CVD apparatus, and more particularly to an optical CVD apparatus having means for increasing the deposition rate.

[Conventional technology]

In recent years, amorphous silicon films have come to be used in various applications, such as optical sensors using amorphous silicon films. Batteries or electrophotographic photoreceptors are widely used as they have good performance. Amorphous silicon film is conventionally plasma CV
It was formed by the D method, the reactive S-Archie method, the Kling method, etc. By the way, in these methods, a film is formed by reacting raw material gas with discharge energy, but since it is difficult to accurately control the discharge energy, it is difficult to form a film with stable performance with good reproducibility. The problem was that it was not possible.

Therefore, photo-CVD, which is relatively easy to control reaction energy,
A law is proposed.

Figure 4 shows a photo-CVD process for film formation using the photo-CVD method.
It is a schematic sectional view of an example of what has been conventionally proposed as a D device. In FIG. 4, reference numeral 11 denotes a reaction vessel, and within the reaction vessel 11 there is provided means 12 for supporting a substrate to which a film is to be applied. Means 13 for heating are provided. A window 14 is formed in the reaction container 11 at a position facing the substrate support means 12 for irradiating high-energy light from the outside into the reaction container 11 . A raw material gas introduction pipe 15 and an exhaust pipe 16 are also connected to the reaction vessel 11 . A raw material gas source (not shown) is connected to the raw material gas inlet pipe 15 through a nozzle valve (not shown), while a raw material gas source (not shown) is connected to the exhaust pipe 16 through a nozzle valve (not shown). A reduced pressure source (not shown), such as a vacuum pump, is connected.

On the other hand, a light source 17 of high energy light is arranged outside the reaction vessel 11.

When forming the film, the substrate A7'C is placed on the substrate support means 12.
For example, a material such as glass or ceramic is fixedly supported, and a material gas such as silane (Si
n4) Introducing gas or disilane (St2H6) gas or the like. Then, while heating the substrate support means 12 and the substrate body by the heating means 13, the light source 17, for example, an excimerade (Exclmer La8or) light source? High-energy light B is irradiated from a fulvon laser light source or a light source in the ultraviolet region such as a mercury lamp or a xenon lamp,
By guiding the light B into the reaction vessel 11 through the window 14 (for example, made of a quartz glass plate that is an ultraviolet-transparent material), the raw materials undergo a photochemical reaction and are formed as a silicon hydride film directly on the substrate. .

The film formation directly on the substrate based on the photochemical reaction described above is expressed, for example, by the following reaction formula.

(184mm) Sin4 SiH4Si+2 H2S1
-→ (deposited as amorphous silicon on the surface of the substrate) [Object of the invention] However, in the photo-CVD apparatus as described above, the raw material gas introduction pipe 15 is opened at the wall surface of the reaction vessel 11.
Further, the substrate support means 12 is located approximately at the center within the reaction vessel 11. Therefore, the raw material gas flow inside the reaction vessel 11 is as shown by the arrow in FIG.
It is roughly averaged over the entire area. The above reaction takes place in the area irradiated with light B above substrate A.
<2. The raw material gas at a position far away from the substrate A is carried by the gas flow to the unreacted 1 or even after the reaction is carried out to the exhaust pipe 1.
It tends to be exhausted from 6. Therefore, the conventional light C
■It is not possible to obtain a sufficient deposition rate with the equipment,
Another problem was that the yield of the deposited film relative to the source gas was low.

The present invention aims to solve the above-mentioned problems@ [Summary of the Invention] According to the present invention, in order to solve the above-mentioned problems of the prior art, An optical CVD apparatus is provided, which is characterized by having means for increasing the raw material gas density compared to the raw material gas density at other positions.

〔Example〕

Hereinafter, specific embodiments of the optical CVD apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing a first embodiment of a photo-CVD apparatus according to the present invention. In FIG. 1, 11 is a reaction vessel, 13 is a heating means, 14 is a window, and 17
is a light source, and these are almost the same as those in the conventional optical CVD apparatus described above.

Reference numeral 18 denotes a substrate support means, and the support means 18 constitutes the bottom surface of the region in the reaction vessel 11 through which the raw material gas flows. 19
is a raw material gas introduction pipe; the tip of the introduction pipe 19 extends into the reaction vessel 11 and opens toward the center of the support means 18 directly above the substrate support means 18; Further, 20 is an exhaust pipe, and the exhaust pipe 20 is connected to the reaction vessel 11 directly above the substrate support means 18.

Preferably, the exhaust pipe 20 is thicker than the inlet pipe 19.

In the apparatus of this embodiment, the raw material gas flow within the reaction vessel 11 is mainly formed on the surface of the gas support means 18, as indicated by the arrow in FIG.

In this way, a photochemical reaction is carried out directly above the substrate A due to the thermal radiation of the light B, and deposition is efficiently carried out on the substrate A.

FIG. 2 is a schematic sectional view showing a second embodiment of the optical CV'D apparatus according to the present invention, and FIG. 3 is a sectional view taken along line 70. In the figures, similar members to those in FIG. 1 are given the same reference numerals.

In this embodiment, the heating means 2 is attached to the side wall of the reaction vessel 11.
For example, a heating resistor is provided.

Reference numeral 22 denotes a raw material gas introduction pipe, and the introduction pipe 22 extends into the reaction vessel 11 and goes around the lower wall surface of the reaction vessel 11 approximately once. Introductory tube 220 reaction vessel l
A plurality of small holes 23 facing upward are obstructed at approximately equal intervals in the inner portion.

24 is an exhaust pipe, which is connected to the bottom of the reaction vessel 11. Reference numeral 25 denotes a base support means, and the base support means 25
A cavity 26 is formed therein for refrigerant circulation, and the support means 25 is supported by an extension 27 located concentrically within the exhaust pipe 24, through which the refrigerant is supplied. It looks like this.

In the device of this embodiment, the base support means 25 is connected to the cavity 26.
The reaction vessel 11 is cooled by circulating a refrigerant, such as water, inside the reaction vessel 11.
The raw material gas is introduced into the reaction vessel 11 through the small hole 23 of the introduction pipe 22 while being heated by the heating means 21 . As a result, the temperature near the substrate A becomes lower than that near the container 11, so that the density of the raw material gas in the container 11 decreases.
It is more flattened in the vicinity. In this way, the irradiation of light B causes a photochemical reaction to occur directly above the substrate A, resulting in efficient deposition on the substrate A.

〔Effect of the invention〕

According to the photo-CVD apparatus of the present invention as described above, the photochemical reaction of the source gas and the deposition can be carried out efficiently, and the deposition rate and yield of the deposited film can be improved.

[Brief explanation of the drawing]

1 and 2 are schematic cross-sectional views of a photo-CVD apparatus of the present invention. FIG. 3 is a sectional view taken along line I-1 in FIG. 2. FIG. 4 is a schematic cross-sectional view of a conventional optical CVD apparatus. 11: Reaction container, 13.21: Heating means, 14: Window, 1
8, 25: Substrate support means, 19.22: Raw material gas introduction pipe, 20.24: Exhaust pipe. Figure 1 Figure 2

Claims (3)

[Claims] (1) Comprising a reaction vessel, a means for introducing a raw material gas into the reaction vessel, and a means for irradiating the raw material gas with high-energy light; 1. A photo-CVD apparatus for depositing a film on a substrate that is attached to a substrate, the photo-CVD apparatus comprising means for increasing the density of a source gas near a substrate support position in a reaction vessel compared to the source gas density at other positions. . (2) The light according to claim 1, wherein the means for increasing the raw material gas density near the substrate supporting position is by discharging gas from the raw material gas introducing means toward the vicinity of the substrate supporting means. CVD equipment. (3) The optical CVD apparatus according to claim 1, wherein the means for increasing the raw material gas density in the vicinity of the substrate support position is by cooling the substrate support means.