JPS62142314A - Plasma cvd apparatus - Google Patents

Abstract

PURPOSE:To enable stable glow discharge to be obtained with good reproducibility by burying an insulating material in the gap between the power supply side electrode and the earth shield. CONSTITUTION:After introducing a material gas into a reaction chamber 19, power is supplied fro a high-frequency power supply 18 through a matching circuit 17 to an electrode 12, glow discharge is generated between an earth electrode 14, and plasma decomposition products, amorphous silicon and the like are deposited on a substrate 16 heated by a heater 15. By burying an insulating material 21 such as fluoroplastic or ceramics in a gap 20 between the electrode to be supplied with power and an earth shield 13, discharge in the gap between the electrode 12 to be supplied with power and the earth shield 13, a prior problem, is dissolved, and there will be no blocking of the gap by the decomposition products. With this, the number of the maintenance times can substantially be reduced, thereby improving the operating efficiency of the plasma CVD apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a plasma CVD apparatus used for manufacturing thin films such as amorphous silicon films.

2. Description of the Related Art Conventionally, this type of plasma CVD apparatus has had a structure as shown in FIG.

That is, in FIG. 2, a raw material gas, for example, silica/(5zH4)rge/I/man(GeH4) is introduced into the reaction chamber 8.
After introducing the gas, the pressure is maintained at several Torr, the high frequency power source 7 is twisted, a glow discharge is generated between the opposing earth electrodes 3, the raw material gas is plasma decomposed, and amorphous silicon and non-crystalline silicon are deposited on the substrate 5. A thin film of crystalline germanium or the like is deposited. Around the electrode 1 to which power is supplied, an earth shield 2 is usually provided with a constant gap 9 of about 2 fl.
This prevents glow discharge from occurring outside the space between the ground electrode 3 and the ground electrode 3.

Problems to be Solved by the Invention However, with such a conventional structure, a strong electric discharge occurs in the upper part of the gap between the electrode 1 to which power is supplied and the earth shield 2, and the raw material gas is e.g. silane gas (5ZH4). In this case, there was a problem in that amorphous silicon, which is a decomposition product 10, formed into seven lakes and was deposited in many places, blocking the gaps.

As shown in FIG. 3, when the electrodes are square, this is particularly likely to occur at the four corners 11 where the discharge is strongly concentrated. In this way, when the gaps are blocked by the decomposition products 1o deposited in many bands, the number of maintenance operations to remove them increases, and if the decomposition products are conductive substances, This results in a loss of input power,
If discharge is no longer possible, the discharge conditions themselves will be different.

Therefore, the present invention solves these problems and prevents a large amount of discharge products from accumulating.

Means for solving the problem The technical means of the present invention for solving the problem are:
An insulator is buried in the gap between the electrode to which power is supplied and the earth shield.

Function: With this structure, an insulator is buried in the gap between the electrode to which power is supplied and the earth shield, making it impossible for electrical discharge to occur.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic diagram of a plasma CVD apparatus according to an embodiment of the present invention. In FIG. 1, 12 is an electrode to which power is supplied, 13 is an earth shield placed around the electrode with a certain gap 20, 14 is a ground electrode, and 15 is a heater that heats the substrate. , 16 is a substrate,
17 is a match 77 circuit, 18 is a high-frequency power source, and 19 is a reaction chamber. These have the same configuration as the conventional example. After introducing raw material gas into the reaction chamber 19, the high-frequency power source 18 is connected. Power is supplied to the electrode 12 through the matching circuit 17.
The plasma decomposition products, amorphous silicon, etc. are deposited on the substrate 16 which is heated by the heater 15.

The structural difference from the conventional example shown in FIG. 2 is that an insulator 21 such as fluororesin or ceramic is embedded in the gap 20 between the electrode 12 to which power is supplied and the earth shield 13. By doing this, the conventional problem of electrical discharge in the gap between the electrode 12 to which power is supplied and the earth shield 13 is eliminated, and there is no possibility that the gap will be blocked by decomposition products. became. Therefore, the frequency of maintenance can be significantly reduced, and the operating rate of the plasma CVD apparatus can be improved.

Furthermore, it has become possible to obtain reproducible and highly reliable glow discharge.

Effects of the Invention As described above, according to the present invention, stable glow discharge can be obtained with good reproducibility. Also plasma CV
It is therefore possible to provide a plasma CVD apparatus which can greatly improve the operating rate of the D apparatus and which has a very large practical effect.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a plasma CVD apparatus in an embodiment of the present invention, FIG. 2 is a schematic diagram of a conventional plasma CVD apparatus,
FIG. 3 is a perspective view of an electrode and a ground shield of a conventional plasma CVD apparatus. 12... Electrode to which power is supplied, 13...
...Earth shield, 14...Earth electrode, I
B... Heater, 16... Board, 2
o・・・Electrode and earth sea Figure 2

Claims (1)

[Claims] 1. A plasma CVD apparatus having a counter electrode, characterized in that an insulator is embedded in a gap between a power supply side electrode and an earth shield.