JPS62174383A - Thin film deposition device - Google Patents

Abstract

PURPOSE:To improve the efficiency of gaseous raw materials and to deposit thin films having no defects such as pinholes by pairing the adjacent substrates of substrates and impressing an AC voltage to the plural substrate pairs. CONSTITUTION:The inside of a vacuum reaction vessel 1 is evacuated ad the gaseous raw material contg. silicon is introduced into the vessel through a gaseous raw material introducing port 6. After the evacuation speed is adjusted, the AC voltage is impressed to the pair of the substrates 2, 3 and the pair of 8, 9 to generate a glow discharge. The exfoliated flake, etc. arising from the electrodes are thereby eliminated and the amorphous silicon films having no defects such as pinholes and recesses are formed. Since AC is impressed to the electrodes, the paired substrates 2, 3 and 8, 9 are made electrically equiv. to each other and the films having the uniform quality are formed. This device is effective particularly for the prepn. of the drum of an electrophotographic sensitive body.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a thin film deposition apparatus, and more particularly to a thin film deposition apparatus suitable for forming an amorphous silicon film by an OVD method.

<Prior Art> Generally, good characteristics can be obtained by forming an amorphous silicon film by a plasma CVD method. plasma CVD
The method uses raw material gas (5in4, 81nH2n+ such as GeH4)
This is a method of depositing an amorphous silicon film on a substrate by glow discharge decomposition of G8n"2n+2, etc.). Glow lightning is generated by applying high frequency to an electrode placed inside or outside a vacuum reaction chamber. Alternatively, there is a capacitive coupling type in which generation is performed by applying a DC voltage, an inductive coupling type in which high frequency power is supplied to a coil placed outside the reaction tank, and a microwave plasma CVD method using microwaves.

<Problems to be Solved by the Invention> Particularly in a capacitively coupled plasma CVD device where the electrode is located inside the reaction tank, if an amorphous silicon film is deposited on the substrate, non-crystalline silicon will be deposited on the surface of the substrate other than the substrate. There is a problem in that the crystalline silicon film or silicon powder is deposited and eventually peels off or falls off and adheres to the substrate, causing film defects such as dents and pinholes.

<Means for Solving the Problems> The present inventors have conducted various studies for the purpose of developing a thin film deposition method that overcomes these difficulties, and have arrived at the present invention. That is, the gist of the present invention is to provide an apparatus in which a plurality of substrates are installed in a vacuum reaction tank equipped with voltage application means, and a thin film is deposited on the substrates by decomposing a gaseous substance by glow discharge. The thin film deposition apparatus is characterized in that adjacent substrates are formed into pairs and an alternating current voltage is applied to the plurality of pairs of substrates.

<Structure of the invention> The present invention will be explained in detail below.

FIG. 1 and FIG. 2 show plasma CVD when producing an electrophotographic photoreceptor using the thin film deposition apparatus according to the present invention.
An example of a device is shown. (Example of several substrates.) Vacuum reaction vessel (
1) A cylindrical substrate (2) for an electrophotographic photoreceptor is placed on a support jig.

This substrate can be heated with a heater (4) in the range of room temperature to about 60θ℃, and is usually made of aluminum, copper, etc.
Selected from metals such as nickel, tantalum, and stainless steel. After evacuating the inside of this vacuum reaction vessel with a vacuum pump through the exhaust port (5), a raw material gas containing silicon (5 in 4, etc.) is introduced through the raw material gas inlet (6), and the pressure is 10 ~
/(After adjusting the pumping speed to about 7 TOrr, the pair of substrate (2) and substrate (3) and the pair of substrate (8) and substrate (
9), an AC voltage is applied by the power supply (7) to generate a glow family t''k.The AC voltage at this time may be a sine wave or a rectangular wave, and the repetition frequency is j Hz to SO
MHz, preferably! OH2-9t OMHz is selected.

Further, the power source may be a single power source or a plurality of power sources corresponding to six pairs.

In this glow discharge decomposition, for example, boron, nitrogen, sulfur, oxygen, etc. can be doped in an amount of usually several ppm to several nitrides.

As carrier gas, H2, H2S, Ar%N! Any commonly used gas may be used. The thickness of the photoconductive layer is usually selected from about 7 to 50 μm, preferably about /Q to 30 μm. When forming the above thin film, 5inH
2H+z, BinX! 50 as the concentration of gas such as n+4
4 or more (volume ratio), voltage 200v to 3 ■, current density fl
0.0/~J mA/cr11 The pressure in the vacuum chamber is in the range of approximately 0.7~j'rorr.

An insulating layer such as aluminum oxide or amorphous silicon oxide may be provided between the substrate and the photoconductive layer, and a surface protective layer such as amorphous silicon carbide or amorphous silicon oxide may be provided on the photoconductive layer by a conventional method. can be provided.

According to the method of the present invention, in a conventionally used plasma CVD apparatus using a capacitive coupling method, the electrodes are of a parallel plate type inside a vacuum chamber (there is a counter electrode parallel to the substrate).

), coaxial cylindrical type (there are concentric opposing cylindrical electrodes around the substrate), etc., this has a great advantage over other types. That is, when it+ is present in the vacuum chamber, there is one point where the amorphous silicon film adheres not only to the substrate but also to the counter electrode, as described above. For example, when forming an amorphous silicon film on a drum-shaped substrate to produce an electrophotographic photoreceptor, if the film is formed for a long time, the amorphous silicon film or amorphous silicon powder attached to the electrode will gradually peel off or come off. When detached and adhered to the substrate, fox pinholes cause film defects. However, according to the method of the present invention, which eliminates the opposing electrode and generates glow discharge by applying an alternating current voltage to the paired substrates, peeling flakes and the like originating from the electrodes are eliminated, so film defects such as pinholes and dents are eliminated. It is possible to form a high-quality amorphous silicon film. Furthermore, since alternating current is applied, the paired substrates are electrically completely equivalent, so a homogeneous film can be formed. On the other hand, by making the substrate rotatable, the uniformity of the film can be further improved.

Furthermore, from an industrial production point of view, according to the conventional method, the amorphous silicon film deposited on the top of the opposing type other than the substrate is not utilized, but according to the present invention, the amorphous silicon film is deposited entirely on the substrate. Since it is formed into a film, there is also the advantage that the raw material gas efficiency that contributes to film formation is significantly increased.

<Effects of the Invention> According to the thin film deposition apparatus according to the present invention, the raw material gas efficiency can be increased and a film with fewer defects such as pinhole lumi film defects can be obtained on the surface. Useful.

[Brief explanation of drawings]

1 and 2 are schematic diagrams representing embodiments of thin film deposition quantities according to the present invention. (1): Vacuum reaction vessel, (2), (3) Two cylindrical substrates, (4): Heater, (6): Raw material gas inlet, (
7); Power supply, (8), (9): Cylindrical substrate Applicant Mitsubishi Chemical Industries, Ltd. Agent Patent attorney Hase - 7 others present

Claims (1)

[Claims] (1) In an apparatus in which a plurality of substrates are installed in a vacuum reaction tank equipped with voltage application means, and a thin film is deposited on the substrates by decomposing a gaseous substance by glow discharge, adjacent substrates A thin film deposition apparatus characterized by applying an alternating current voltage to a plurality of pairs of substrates.