JPS6055352A - Manufacture of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To lower residual potential by introducing a gas specified in B/Si ratio into a glow discharge chamber to form an intermediate layer, at the time of forming the intermediate layer made of amorphous silicon as an electrophotographic sensitive body and electrostatic charge barrier layers on both or one of its surface and the interface with a conductive substrate. CONSTITUTION:In forming an electrophotographic sensitive body made of amorphous silicon (a-Si) and charge barrier layers on its surface and its interface with a conductive substrate, this a-Si layer is doped with an extremely small amt. of B. The requirements of this a-Si layer are as follows: An amt. of thermal carriers to be produced is small when it is not exposed to light and dark decay time is long, and when exposed to light, photocarriers produced must be transferred rapidly. Residual potential can be reduced without lowering initial surface potential by introducing a gas controlled to a B/Si ratio of 0.2-2ppm into a glow discharge chamber and doping the a-Si film with an optimum amt. of B corresponding to it to fulfill said requirements.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method for manufacturing an amorphous silicon photoreceptor having a low residual potential and high charging ability.

(Prior Art) Glow discharge decomposition of SIH4 is commonly used to fabricate electrophotographic photoreceptors from amorphous silicon a-8i.

In this case, the resistivity of A-8I, which is not used as an example, is usually 10.
Since the resistance is 10Ω or less, it is not possible to hold charges on the surface. Therefore, there is a method of doping oxygen or nitrogen to increase the resistance of the film, or adding a-SiC or a-8iN to the surface of the a-8i layer or the interface with the substrate.

An n-type or p-type a-3i layer is provided using a high-resistance material such as a-8iOx, or depending on the positive or negative surface charge.
The necessary charging ability is obtained by using a method that prevents charge injection from the surface or substrate. This charge blocking layer has a thickness of several 100×-1 μm depending on the material, manufacturing method, and purpose.

On the other hand, the conditions required for the intermediate a-3i layer are the first
If no light is applied, the generation of thermal carriers is small and the dark decay time is long, and secondly, if light is applied, the generated photocarriers are quickly transported to the interface without being captured on the way. required to do so. However, when producing the a-3i film by plasma CVD' (glow discharge method),
The first requirement and the second requirement are contradictory conditions. When using a-8i as an electrophotographic photoreceptor, a film thickness of about 20 μm or more is usually required to obtain sufficient charging ability, so it is produced by high-speed growth (about 10/- or more). Then, the a-8t used for solar cells, optical sensors, etc.
There are various defects (5iH
There are many levels created by n (n = 2, 3), dangling bonds, micro voids, etc.). As a result, even if the first requirement is almost satisfied, the second requirement is not. In particular, in the case of positive charging, if there is a deep trapping level for holes in the a-8i layer, the holes trapped there are difficult to be excited again by heat, which is considered to be the cause of residual potential.

(Objective of the Invention) The present invention solves the above-mentioned drawbacks by doping a trace amount of boron into the a-3i layer, and will be described in detail below.

(Structure of the invention) This will be specifically explained below using examples.

FIG. 1 shows an example of a charge blocking type A-8T photoreceptor for positive charging. The first layer is a p-type a-8i layer doped with about 1100 pp of noborane (B2H6) and has a thickness of about 0.5 μm to prevent injection of electrons from the substrate. Also, the third layer is a
-The SiC layer has a thickness of about 0.1 μm and functions to prevent injection of holes from the surface and stabilize the surface.

The second intermediate layer is an a-8i layer, and this intermediate layer is formed to a thickness of about 20 μm by introducing noborane and silane into the glow discharge chamber, and the introduced gas ratio (B 2
H6/S'H4) is about 0.4 ppm, so the ratio of poron to St is about 0.8 ppm. The initial surface potential of the electrophotographic photoreceptor thus prepared was approximately 300 volts (
However, the corona discharge voltage is +7 volts), which is not much lower than the initial surface potential without the addition of poron (approximately 330 volts), and the residual potential is approximately 20 volts (however, the incident wavelength is 650 nm). ), the residual potential is significantly lower than that without boron addition (approximately 100 volts).

FIG. 2 shows the tendency of the initial surface potential V8o and the residual potential Vr with respect to the gas introduction ratio of B2H6 and SiH4. lppm~1ppm
(Ratio of yjeron to silicon Uo, 2ppm~2
ppm), the initial surface potential does not decrease excessively and the residual potential can be significantly reduced.If the variation in growth conditions is taken into account, the range is 0.2 ppm to 0.5 ppm (
(ratio of boron to silicon, 0.4 ppm to lppm)
is optimal.

(Effects of the Invention) According to the present invention, by finding the optimum amount of boron depending on the film quality of a-8T and doping it, the residual potential can be reduced without lowering the initial surface potential.

[Brief explanation of drawings]

FIG. 1 is a simplified cross-sectional view showing the structure of a charge-blocking type A-8i photoreceptor, and FIG. 2 is a characteristic diagram showing the dependence of the initial surface potential (Vso) and residual potential (Vr) on the amount of boron dope. . Patent Applicant Oki Electric Industry Co., Ltd. 422- Figure 1 Figure 2 Procedural Amendment (Mutsu) ], Case Description 1981 Patent Application No. 163174 2 Title of Invention Method of Manufacturing Electrophotographic Photoreceptor 3 Amendment Relationship with the patent applicant case Address (〒105) 1-7-12 Toranomon, Minato-ku, Tokyo
No. 4, Agent address (105) 1-7-12 Toranomon, Minato-ku, Tokyo
No. 6, Contents of the amendment (1) From line 17 to line 18 of page 2 of the specification, the phrase “What is the first condition and the second requirement?” has been changed to “the first condition and the second condition.” What are the conditions?'' (2) On page 3, line 6 of the same 1, amend "the first requirement is" to "the first condition is." (3) On page 3, line 6 of the Ministry of Health, “The second requirement is”
``The second condition is'' is corrected. (4) Amend the drawing “Figure 2” as attached.

Claims (1)

[Claims] In a method for manufacturing an electrophotographic photoreceptor having a charge blocking layer on both or one of the surface and the interface of a conductive substrate and the intermediate layer being amorphous silicon, the ratio of boron to silicon is 0.2 ppm. A method for manufacturing an electrophotographic photoreceptor, characterized in that the intermediate layer is formed by introducing gas at a concentration of ~2 ppm into a glow discharge chamber.