JPH029673B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field of the Invention> The present invention relates to an improvement in an apparatus for manufacturing an amorphous silicon photoreceptor.

<Technical background of the invention and its problems> Conventionally, plasma has been used as an apparatus for manufacturing amorphous silicon (hereinafter aSi) photoreceptors.
A CVD (hereinafter P-CVD) device is used as the most suitable device. In this device, one or more photoreceptor substrates are installed in a vacuum reaction tank, which is grounded, and an electrode, which is generally shaped to surround the substrate, is installed, and high-frequency power is applied to this to react in a vacuum. A raw material gas such as monosilane (SiH ₄ ) gas introduced into the tank is turned into a plasma state by electric discharge, and the effective radicals (groups) generated in this plasma are generated on the substrate.
This device is designed to form an aSi film.

Conventional aSi photoreceptor manufacturing equipment consists of one or more capacitively coupled cylindrical P-CVD equipment arranged in a circle or in series, and each substrate rotates on its own axis to produce a uniform film thickness. Efforts have been made to obtain an aSi film. The raw material gas is generally introduced from the top. It has also been proposed that a raw material gas jetting pipe with many holes is introduced into the reaction tank, and the raw material gas is introduced through the many holes so that the gas concentration is homogeneous in the tank. In most devices, the reaction tank is evacuated from the bottom of the reaction tank.

However, in such a conventional device, the gas path flowing through the reaction tank is short, and therefore the efficiency with which the raw material gas is converted into the aSi film on the substrate is low, and the efficiency is usually about ten-odd percent at most. Furthermore, when depositing films on multiple substrates using conventional equipment, although each substrate rotates on its own axis, it is extremely difficult to deposit a uniform aSi film on all the substrates in the reaction tank. It was hot.

<Object of the Invention> The present invention has been made for the purpose of solving the above-mentioned drawbacks of the prior art and providing an apparatus for efficiently manufacturing a uniform and homogeneous aSi photoreceptor.

<Configuration of the Invention> In order to achieve the above object, an apparatus for manufacturing an amorphous silicon photoconductor of the present invention uses plasma CVD.
The reaction tank of the apparatus is cylindrical with circular outer and inner walls, and a plurality of photoreceptor substrates made of cylindrical conductors are placed in the cylindrical reaction tank at positions approximately equidistant from the outer and inner walls. The cylindrical conductors are arranged at equal intervals on the same circumference so that their axial directions are parallel to the central axis of the cylindrical reaction tank, and high-frequency power for plasma generation is applied to the photoreceptor substrate. The present invention is characterized in that plasma is generated between the above-mentioned outer wall and inner wall, which are set at a ground potential, and the above-mentioned photoreceptor base.

<Embodiment of the Invention> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the schematic configuration of the embodiment device, and FIG.
The figure is a horizontal cross-sectional view showing an example of the structure of the reaction tank of the embodiment apparatus, and FIG. 3 is a cross-sectional view taken along the line A-A' in FIG.

In Fig. 1, 1 is a raw material gas cylinder, 2 is a gas flow rate controller, 3 is a reaction tank, 4, 4, ... are cylindrical conductors placed in the reaction tank 3, 5 is a mechanical booster pump system, and 6 is an exhaust gas. A processing section, 7 is a high frequency power supply, 8 is a matching box, and a reaction tank 3.
In contrast, raw material gas is introduced from a raw material gas cylinder 1 through a gas flow rate control section 2 . Exhaust gas passes through a mechanical booster pump system 5 to an exhaust gas treatment section 6
and processed. Further, high frequency power is applied from a high frequency power source 7 via a matching box 8 to each cylindrical conductor 4, 4,... in the reaction tank 3 as described later, and arranged in a circular shape within the reaction tank 3. The inner and outer electrode parts are grounded. As shown in FIG. 2, the reaction tank 3 is formed into a double cylindrical shape with a circular center. An outer electrode 21 is formed on or adjacent to the inner surface of the outer peripheral wall 11, and an inner electrode 22 is formed on or adjacent to the outer surface of the inner peripheral wall 12. Therefore, the outer electrode 21 and the inner electrode 22 also constitute a double cylindrical electrode with a circular center in relation to the reaction vessel 10. Further, the inner circumferential wall 12 provided with the inner electrode 22 is fixed to an upper lid 23 provided so as to be openable and closable as shown in FIG.
An electrically conductive rotating shaft 24 connected to a drive source (not shown) is mounted on the bottom of the reaction tank 3, and an insulating member 2 is connected to the center of the bottom of the reaction tank 3.
5, and is rotatably inserted through the rotating shaft 24.
A conductive gear 26 is fixed, and this conductive gear 2
A plurality of rotating gears 28, 28, .
are arranged, and the rotating shafts 29, 29,...
1 and 22 are arranged at equal intervals on the same circumference and equidistant from each other. Each photoreceptor base 4 made of a cylindrical conductor,
By aligning the central axes of the rotating gears 28, 28, 29, 29, . . . with the central axes of the rotating gears 28, 28, .
Photoreceptor substrates 4, 4, . . . made of cylindrical conductors are arranged at equal intervals on the same circumference equidistant from electrodes 1 and 22, with their axial directions parallel to the central axes of electrodes 21 and 22. A plurality of them will be arranged in the reaction tank 3. Each photoreceptor base 4, 4, . . . is connected to a drive source (not shown) and a gear mechanism 26, 2 shown in FIG.
8, etc., each photoreceptor substrate 4, 4, . . . revolves around the circumference on which it is placed while rotating. Second
The figure shows a case where it rotates in the direction of the Q arrow and revolves in the direction of the P arrow. An inlet 40 for introducing raw material gas into the reaction tank 3 and an outlet 50 for exiting the reaction tank 3 are provided on the outer circumferential wall 11 of the reaction tank 3 at a relative position of 180° to each other.

In the above configuration, the high frequency power supplied from the high frequency power supply 7 is transmitted to the rotation shaft 24 and the gear mechanism 2.
6, 28, etc., to each photoreceptor substrate 4, 4, ... which is insulated from the reaction tank 3 body, and plasma is applied to the space between the circular inner wall 12 and outer wall 11, which are at ground potential. occurs, and on the substrate 4, 4,...
An aSi film is deposited.

In addition, the path through which the raw material gas 1 flows is long, and the gas 1 passes around several substrates 4, 4,..., so that the raw material gas is effectively used before being exhausted, greatly increasing its utilization efficiency. This will be improved.

Further, since the substrates 4 simultaneously rotate and revolve within the reaction tank 3, a homogeneous aSi film is formed on all the substrates 4 in the reaction tank 3.

Furthermore, by connecting the base 4 to the high frequency side and setting the outer and inner walls facing the base 4 to the ground potential, the positive column of the plasma comes close to the base 4, increasing the film formation rate. become.

Next, to describe an embodiment of the present invention by citing actual specific values, for example, 10cm
8 Al cylinder bases 4 with the same diameter, and inner and outer electrodes 21, 2
2, and the rotation speed of the bases 4, 4, ... is set between 4 and 2.
It was designed to perform 10 revolutions/min, with a revolution speed of 1 to 2.5 revolutions/min. Then, a high frequency power of about 400 W at 13.56 MHz is transmitted to the 8
Plasma discharge was performed at a gas pressure in the tank of 0.3 Torr using only monosilane (SiH ₄ ) gas as a raw material gas, with the inner and outer walls of the reaction tank 3 grounded, and with a gas pressure in the tank of 0.3 Torr. . At this time, the substrates 4, 4, . . . are heated to about 250°C.

The aSi on all the substrates 4, 4, . . . obtained under these conditions was homogeneous and had a uniform thickness. Estimating the conversion efficiency of gas to aSi from the film thickness, it is approximately 30%, which is approximately three times the efficiency of conventional equipment. The film deposition speed was improved by approximately 40%.

<Effects of the Invention> As described above, according to the present invention, the positive column of plasma is connected to the substrate by connecting the substrate to the high frequency side and setting the outer and inner walls of the reaction tank facing the substrate to the ground potential. As a result, the film formation rate can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a schematic configuration of an apparatus according to an embodiment of the present invention, FIG. 2 is a horizontal sectional view showing an example of the configuration of a reaction tank of an apparatus according to an embodiment of the present invention, and FIG. 3 is an A in FIG. 2. It is a diagram showing a −A′ cross section. 3... Reaction tank, 4... Photoreceptor base, 7... High frequency power supply, 11... Outer circumferential wall, 12... Inner circumferential wall, 21... Outer electrode, 22... Inner electrode.

Claims (1)

[Scope of Claims] 1. The reaction tank of the plasma CVD apparatus is cylindrical with concentric outer and inner walls, and a plurality of photoreceptor substrates made of cylindrical conductors are disposed within the cylindrical reaction tank from the outer and inner walls. The cylindrical conductors are arranged at equal intervals on the same circumference at positions approximately equidistant from each other so that their axial directions are parallel to the central axis of the cylindrical reaction tank, and the outer and inner walls are set to ground potential. and applying high-frequency power for plasma generation to the photoreceptor base to generate plasma between the outer and inner walls set at ground potential and the photoreceptor base. Equipment for manufacturing asilicon photoreceptors. 2. Claims characterized in that the inlet of the raw material gas into the reaction tank and the outlet from the reaction tank are provided at a relative position of 180° on the outer wall side circumferential surface of the cylindrical reaction tank. 2. The apparatus for manufacturing an amorphous silicon photoreceptor according to item 1.