JPS60223114A - Production apparatus for semiconductor film - Google Patents

Abstract

PURPOSE:To reduce the generation of defects due to plasma ion bombardment, and to obtain a uniform semiconductor film having excellent quality by using multiple-split type plasma electrodes in a CVD method by plasma. CONSTITUTION:There are a heater 2 for heating a substrate, a substrate susceptor 3 and multiple-split type cathode electrodes 5 and anode electrodes 6 for generating plasma in a vacuum vessel 1, and the cathode electrodes 5 and the anode electrodes 6 are mounted in the same plane. The electrodes 5, 6 for generating plasma are disposed so as to approximately run parallel with the surfaces of the substrates 4. Accordingly, since the cathode electrodes and the anode electrodes are split multitudinously and distances among both electrodes are shortened and the plasma electrodes are constituted in the same plane, the generation of plasma is started smoothly, and stable plasma is acquired, thus preventing defects generated in the surfaces of semiconductor films and films on the substrates due to plasma ion bombardment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a semiconductor film manufacturing apparatus, and particularly to a CVD (CVD)
(chemical vapor deposition)
This invention relates to an electrode structure in a semiconductor voice-making device manufactured by a method.

[Background of the invention]

When a semiconductor film is formed on a substrate by a method (CVD method) in which crystals or amorphous materials are deposited on a substrate from a gas phase through a chemical reaction using plasma, the substrate is deposited by plasma ion bombardment. In order to prevent defects occurring on the surface and inside of the upper semiconductor film, the conventional technology (1
) A method in which a mesh electrode is provided between the cathode electrode and the anode electrode, and a DC voltage is applied to this to prevent ion bombardment.
rs P, 290. M.

Edited by H. Brodsky, Spring-VerZa
(1979), or (2) a method using a reactor using a cross electric field method (Applied Physics 50 P, 346 (1981)). However, in the method (1) in which a mesh electrode is provided between both electrodes and a DC bias voltage is applied to prevent ion bombardment, the deposition rate of the semiconductor layer is significantly reduced, productivity cannot be improved, and the bias voltage Therefore, there is a problem that the plasma is disturbed and it is not possible to obtain a uniform and high quality semiconductor film.In addition, in the case of a reactor using the cross electric field method (2), the distance between the cathode electrode and the anode electrode is large. However, there is a problem that a difference occurs in the plasma ion concentration (the concentration is higher on the anode side), which causes unevenness in the deposition rate of l\ on the substrate, making it difficult to obtain a semiconductor layer with a uniform thickness.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor film manufacturing apparatus that eliminates the above-mentioned drawbacks of the prior art and can form a semiconductor film of uniform thickness and high quality at high speed using a plasma CVD method. shall be.

[Summary of the invention]

In short, the present invention provides the following advantages in the CVD method using plasma:
A cathode electrode and an anode electrode, which are electrodes for generating plasma to decompose a reactive gas, are divided into various parts and provided in the same plane, and the substrate surface on which a semiconductor film is to be formed is set relative to the plane of the divided plasma electrode. This is a semiconductor film manufacturing apparatus that forms thin films by arranging them so that they are substantially parallel to each other.

In the present invention, the cathode electrode and the anode electrode are divided into various parts to shorten the distance between the two electrodes, and the plasma electrodes are arranged in the same plane, so that the plasma generation starts smoothly and the plasma becomes stable. This makes it possible to prevent defects occurring on the surface and inside of the semiconductor film on the substrate due to plasma ion bombardment, and because the distance between the cathode and anode is small, the difference in plasma ion concentration between the two electrodes can be prevented. There is almost no occurrence, and a semiconductor film with a uniform thickness can be manufactured.

Further, in the present invention, since there is no need to apply a DC bias voltage to prevent ion bombardment, the deposition rate of the semiconductor layer is increased and productivity can be improved.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a schematic structure of a semiconductor film manufacturing apparatus according to the present invention. As is clear from the figure, vacuum container 1
Inside, there are a heater 2 for heating the substrate, a substrate holding table 3, and a multi-divided cathode electrode 5 and an anode electrode 6 for generating plasma.The cathode electrode 5 and the anode electrode 6 are arranged in the same plane. is set up. This plasma generation electrode 5.6 is arranged so as to be substantially parallel to the surface of the substrate 4. The substrate 4 on which the semiconductor layer was deposited was placed facing downward. A pipe for introducing a reaction gas is provided at the bottom of the vacuum container 1, and a pipe for a vacuum exhaust system is connected to the top.

(Example 1) FIG. 2 is a plan view showing the structure of an electrode for generating plasma. As shown in the figure, the cathode electrode 7 and the anode electrode 8 of the multi-branched split type are arranged so that the shortest distance between adjacent multi-branch electrodes is constant. In order to generate plasma by glow discharge at a reaction gas pressure within the range of several tens of Torr to several Torr, the shortest distance between the cathode and anode electrodes is suitably 10 mm to 200 mn. In this example, the shortest distance between the electrodes was set to 50 mm. A power source with a plasma excitation frequency of 13.56 MHz was connected to the cathode electrode 7 and the anode electrode 8 to generate plasma. Monosilane (SiH,) is introduced into the vacuum container 1 as a reaction gas,
The degree of vacuum in the container is maintained at 0.5 Torr, and plasma is generated to decompose SiH4 and convert amorphous silicon into substrate 4.
deposited on the surface of Note that the substrate is heated to an appropriate temperature in order to increase surface diffusion of the atoms that have arrived, improve film quality, and improve adhesion to the substrate. Doping gases include diporane (B, HG) and phosphine (1).
A PIN-type amorphous silicon photoelectric conversion device was fabricated using P Ha ).

The uniformity of the thickness of the deposited amorphous silicon is 250 mm.
The film thickness uniformity was ±5% for the X 400no substrate, which was a significant improvement compared to the film thickness uniformity of ±30% obtained by the conventional cross electric field method. Furthermore, the deposition rate of amorphous silicon is also about 34% faster than that of the conventional parallel plate type plasma generation electrode. When this photoelectric conversion element with a uniform film thickness was applied to a solar cell, the energy conversion efficiency could be improved by about 11% compared to the conventional technology.

(Embodiment 2) FIG. 3 is a plan view showing the structure of an electrode according to another embodiment of the present invention for generating plasma. As shown in the figure, a multi-split cathode electrode 9 and anode 1 to electrode 1
The respective electrodes are arranged so that the shortest F1 distance of the manifold electrodes that are in contact with each other by liJ changes continuously and periodically. In the case of this embodiment, the shortest distance between the two electrodes of 1o continuously changes from 20 books to 60 books. The plasma excitation frequency, the type of reaction gas, and the method of depositing the amorphous silicon film are exactly the same as in Example 1.

In this example, the uniformity of the film thickness was ±5%, which is the same as in Example 1, and the deposition rate of amorphous silicon was approximately 33% compared to that of the conventional parallel plate type plasma electrode. It got faster. In this example, the plasma started smoothly, stable plasma was obtained, ion bombardment against the substrate surface was prevented, and a high quality and uniform semiconductor film was formed. In this case, the energy conversion efficiency was significantly improved to about 15%.

〔Effect of the invention〕

As explained in detail above, when manufacturing a semiconductor film using the multi-split plasma electrode according to the present invention, there are few defects caused by plasma ion bombardment, and the plasma ion concentration acts uniformly on the substrate. A uniform and high-quality semiconductor pattern can be obtained. Therefore, when this is applied to solar cells, energy conversion efficiency can be significantly improved.

Further, according to the present invention, since there is no need to apply a DC bias voltage to prevent plasma ion bombardment, the semiconductor layer can be deposited more than 4 times, thereby improving productivity.
The practical effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a schematic structure of a semiconductor film manufacturing apparatus according to the present invention, and FIGS. 2 and 3 are plan views showing the structure of an electrode for generating plasma according to the present invention. 1... Vacuum container 2... Heater for heating the substrate 3...
Substrate holding stand 4...Substrate 5.7.9...Cathode electrode 6.8, lO...Anode electrode Attorney Junnosuke Nakamura 1 Figure ↑ and A Migasai 2 Figure

Claims (1)

[Scope of Claims] 1. A split-type plasma electrode in which a cathode electrode and an anode electrode, which are electrodes for generating plasma for decomposing a reactive gas, are divided into various parts, The type plasma electrode is installed in the same plane as an arbitrary plane in the reaction chamber, and the substrate surface on which the semiconductor film is to be formed is arranged so as to be substantially parallel to the plane of the divided type plasma electrode. 1. A semiconductor film manufacturing apparatus, characterized in that a thin film is formed using a semiconductor film. 2. Claim 1, characterized in that the split cathode electrode and anode electrode are constructed of metal strips, wires, or rods, or a combination thereof.
An apparatus for manufacturing a semiconductor film as described in 1. In the J0 split type cathode electrode and anode electrode, the shortest distance between the two electrodes is from 10nwn to 200I.
3. The semiconductor film manufacturing apparatus according to claim 2, wherein the semiconductor film manufacturing apparatus is arranged at a constant distance within a range of . 4. Claim No. 4, characterized in that the split cathode electrode and anode electrode are arranged so that the shortest distance between them varies continuously in a certain pattern within a range of 10 mm to 200 m. 2. The semiconductor film manufacturing apparatus according to item 2.