JPH0350264B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an electrophotographic device used in an electronic copying machine, an electronic printer, or the like.

(Prior Art) Amorphous silicon (a-Si) is being used mainly in semiconductor application technology such as solar cells, but in recent years there have been proposals to apply this type of amorphous silicon to electrophotography technology.

This type of amorphous silicon has been recognized to be useful as a material for electrophotographic photoreceptors, which are electrostatic latent image carriers in copiers, non-impact printers, etc., due to its wear resistance and sensitivity to long wavelength light. Depends on what is being done.

(Problem to be Solved by the Invention) By the way, an electrophotographic photoreceptor using amorphous silicon also forms an amorphous silicon (a-Si) film on a conductive substrate by glow discharge decomposition of SiH ₄ gas. It becomes. However, a hydrogenated amorphous silicon (a-Si:H) film formed using pure _SiH4 gas has a specific resistance of 10 ¹¹ Ω in the dark.
Because of its small size (cm), it is not possible to maintain a sufficient surface potential even when DC corona charging is performed during the electrophotographic process.

Therefore, it has been considered to dope oxygen to increase the dark resistance of the amorphous silicon film. In other words, in a hydrogenated amorphous silicon oxide film (a-Si:O:H film) formed using a mixed gas of SiH ₄ gas and O ₂ gas, the resistance in the dark can be reduced by controlling the O ₂ concentration. 10 ¹¹
It can be made more than Ωcm. However, at the same time, the resistance during light irradiation became more than 10 ¹¹ Ωcm.
Since sufficient photosensitivity cannot be obtained, it cannot be used as an electrophotographic photoreceptor.

The present invention has been made based on the above circumstances, and an object thereof is to provide an electrophotographic photoreceptor having excellent charging characteristics, dark decay characteristics, and photosensitivity characteristics.

[Structure of the Invention] (Means for Solving the Problems) The electrophotographic photoreceptor of the present invention includes a conductive substrate, a first hydrogenated amorphous silicon oxide film formed on the conductive substrate, and a first hydrogenated amorphous silicon oxide film formed on the conductive substrate. A hydrogenated amorphous silicon oxide film formed on the first hydrogenated amorphous silicon oxide film, and a second hydrogenated amorphous silicon oxide film formed on the hydrogenated amorphous silicon oxide film, The first and second hydrogenated amorphous silicon oxide films are coated with a silicon-containing gas at a flow rate ratio to this gas.
The hydrogenated amorphous silicon film is formed using a glow discharge of a gas mixed with 0.5% or more of oxygen, and the hydrogenated amorphous silicon film is characterized in that it is formed using a glow discharge of a gas containing silicon but not containing oxygen.

(Function) When a hydrogenated amorphous silicon film is formed in the presence of oxygen gas, a hydrogenated amorphous silicon oxide film is formed, and Si=O bonds are formed in the Si-Si bonds, which localize electrons. , resulting in a decrease in photoconductivity.

In contrast, hydrogenated amorphous silicon
A three-dimensional structure centered on Si-Si bonds is formed, and dangling bonds are compensated for by Si-H bonds, making it possible to maintain high photoconductivity with less electron localization.

Therefore, in the electrophotographic photoreceptor of the present invention, a hydrogenated amorphous silicon oxide film that does not contain oxygen is sandwiched between first and second hydrogenated amorphous silicon oxide films that contain oxygen. The dark resistance is improved by the first and second hydrogenated amorphous silicon oxide films, and the photosensitivity is improved by the hydrogenated amorphous silicon film which does not contain oxygen.

(Example) An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows an apparatus for manufacturing an electrophotographic photoreceptor according to the present invention. In the figure, reference numeral 1 indicates a base of the apparatus main body, and a vacuum chamber 2 is provided on this base 1. . A counter electrode is provided within the vacuum chamber 2, and a gas passage 4 is provided within the counter electrode 3. In addition, the counter electrode 3
A jet hole 5 communicating with the gas passage 4 is provided on the circumferential surface of the
A large number of gas passages 4 are drilled therein, and a gas introduction pipe 6 is connected to the gas passage 4. A valve 7 is disposed in the gas introduction pipe 6, and on the upstream side of the valve 7, a gas cylinder 8 containing silane (SiH ₄ ) and a gas cylinder 9 containing oxygen (O ₂ ) are installed at the respective valves. They are connected via 10 and 11. By adjusting the opening degrees of these valves 10 and 11, only one gas or both gases can be supplied to the valve 7 at the required flow rate.
It can be introduced into the chamber 2 through the.

Further, at the bottom of the chamber 2, there is a turntable 12 driven by a motor (not shown).
An Al drum substrate 13 as a conductive substrate is disposed on the turntable 12, and a heater 14 is fixedly installed inside the Al drum substrate 13. In addition, the above base 1
A discharge pipe 15 communicating with the inside of the chamber 2 is connected to the discharge pipe 15, and a diffusion pump 16 is connected to the discharge pipe 15.
and a rotary pump 17 are provided.

Next, a procedure for manufacturing an electrophotographic photoreceptor using the manufacturing apparatus configured as described above will be described.

First, the Al drum substrate 13 set in the chamber 2 is heated by the heater 14 and maintained at 250°C, and oxygen (O ₂ ) gas and pure silane gas, which is a gas containing silicon, are heated through the introduction pipe 6. A mixed gas was introduced into chamber 2. At this time, the mixed gas contained oxygen at a flow rate ratio of 0.5% or more to the silane gas, and the flow rate of the silane gas was 50 SCCM.

Next, when the pressure inside the chamber 2 is reduced to 0.1 Torr, the RF power supply 19 is activated, and the counter electrode 3 is
A high frequency power of 10 W was applied to bring the gas in the chamber 2 into a plasma state due to glow discharge, and film formation was performed for 15 minutes. As a result, as shown in Figure 2,
A first hydrogenated amorphous silicon oxide film 19 was formed on the Al drum substrate 13 to a thickness of about 0.1 μm.

Next, the inflow of only oxygen (O ₂ ) gas was stopped, and high frequency power of 100 W was applied at the same pressure to generate a glow discharge, and the gas in the chamber 2 was brought into a plasma state. This state was maintained for 5 hours, and a hydrogenated amorphous silicon film 20 was formed on the first hydrogenated amorphous silicon oxide film 19 to a thickness of 15 μm.

Next, film formation is performed for 15 minutes under the same conditions as the beginning, that is, oxygen is mixed in addition to silane gas, and the high frequency power is 10 W, to form a second hydrogenated amorphous silicon oxide film 21 on the hydrogenated amorphous silicon film 20. was formed.

The electrophotographic photoreceptor manufactured in this way is
The first and second hydrogenated amorphous silicon oxide films 19 and 21 prevent charge injection from the conductive substrate 13 and prevent surface charge from flowing out, increasing dark resistance and increasing charge retention ability. The hydrogenated amorphous silicon film 20 generates a charge upon receiving light and has a charge generation function that acts as a photoconductor, so it has excellent charging characteristics, dark decay characteristics, and photosensitivity characteristics. Indicated.

The changes in the surface potential when a +8kV corona discharge was applied to this photoreceptor and the exposure residual potential after 100 lux irradiation were measured during the formation of the first and second hydrogenated amorphous silicon oxide films 19 and 21. Oxygen ( _O2 )
The graph in FIG. 3 is plotted against the flow rate ratio. As is clear from FIG. 3, the surface potential increases as the oxygen flow rate ratio increases, and therefore the charge retention ability increases. on the other hand,
The residual potential is uniformly low, independent of the oxygen flow rate ratio.

Next, oxygen is added to the silane gas when forming the hydrogenated amorphous silicon film 20 without changing the amount of oxygen during the formation of the first and second hydrogenated amorphous silicon oxide films 19 and 21. A photoreceptor was similarly produced under the same conditions as described above, except that the amount was changed. +8kV to these photoreceptors
The changes in the surface potential during corona discharge and the exposure residual potential after 100 lux irradiation were determined, and the results shown in FIG. 4 were obtained.

From the graph in Figure 4, it can be seen that when the film 20 is formed by adding oxygen to the silane gas, the residual potential increases rapidly and the photoconductivity decreases, compared to the case where oxygen is not included (Figure 3). It can be seen that

[Effects of the Invention] As explained above, according to the present invention, a first hydrogenated amorphous silicon oxide film is formed on a conductive substrate using glow discharge of a mixed gas of a gas containing oxygen and silicon. A hydrogenated amorphous silicon film is formed on this first hydrogenated amorphous silicon oxide film using glow discharge of a gas that contains at least silicon and does not contain oxygen, and on this hydrogenated amorphous silicon film. By forming the second hydrogenated amorphous silicon oxide film in the same manner as the first hydrogenated amorphous silicon oxide film, excellent charging characteristics, dark decay characteristics, and photosensitivity characteristics can be obtained. It has excellent effects.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of an apparatus for manufacturing an electrophotographic photoreceptor according to the present invention, FIG. 2 is a sectional view showing an electrophotographic photoreceptor of the invention manufactured by the same apparatus, and FIG. Regarding SiO ₄ gas during formation of the first and second hydrogenated amorphous silicon oxide films
A graph showing the relationship between O ₂ gas flow rate ratio, charging potential, and residual potential, and _{FIG .}
FIG. 2 is a graph diagram showing the relationship between gas flow rate ratio, charging potential, and residual potential. 13... Conductive substrate (Al drum substrate), 19...
...first hydrogenated amorphous silicon oxide film, 2
0... Hydrogenated amorphous silicon film, 21...
Second hydrogenated amorphous silicon oxide film.

Claims (1)

[Claims] 1 a conductive substrate, a first hydrogenated amorphous silicon oxide film formed on the conductive substrate,
A hydrogenated amorphous silicon film formed on the first hydrogenated amorphous silicon oxide film,
a second hydrogenated amorphous silicon oxide film formed on the hydrogenated amorphous silicon film, and the first and second hydrogenated amorphous silicon oxide films contain a gas containing silicon; The hydrogenated amorphous silicon film is formed using a glow discharge of a gas mixed with oxygen at a flow rate ratio of 0.5% or more to the gas, and the hydrogenated amorphous silicon film is formed using a glow discharge of a gas containing silicon but not containing oxygen. An electrophotographic photoreceptor characterized by: