JPH0212260A - Electrophotographic sensitive body and production of same - Google Patents

Abstract

PURPOSE:To enhance electric conductivity and potential stability of an amorphous silicon photosensitive body by specifying a ratio of the integrated intensity of infrared spectra of a photoconductive layer at about 880cm<-1> to that at about 840cm<-1>. CONSTITUTION:The photoconductive layer is made of the amorphous silicon (a-Si) type material, and the ratio of the integrated intensity of its infrared spectra at about 880cm<-1> I1 to that at about 840cm<-1> I2 is regulated to 0.2<I2/I1<0.6, thus permitting heating of a substrate to be made unnecessary for such a photosensitive body by using the electron cyclotron resonance method, said intensity ratio to be controlled in a proper range, and accordingly, the conductivity and potential stability of the a-Si photosensitive body to be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION ta+ Industrial Field of Application This invention provides a photoconductive layer made of amorphous silicon (hereinafter referred to as
The present invention relates to an electrophotographic photoreceptor made of a)-based material referred to as a-5i, and a method for manufacturing the same.

B) Conventional technology An electrophotographic photoreceptor (hereinafter referred to as an a-Si photoreceptor) whose photoconductive layer is made of an a-Si-based (containing H, etc.) material is non-polluting,
High light sensitivity, high hardness (Hv: 1500-2000kg
Because it has many excellent properties such as / fin 2), it is being developed as an ideal photosensitive material.

The a-Si photoreceptor is generally produced using the plasma CVD method.

It is manufactured by a method such as a sputtering method. In the plasma CVD method, a raw material gas such as monosilane or disilane is introduced into a vacuum chamber equipped with a photoreceptor substrate such as aluminum, and the raw material gas is decomposed by a glow discharge caused by the application of high-frequency power. The sputtering method uses a Si wafer as a target, and sputters the target by introducing H2 and rare gases such as ^r and e, and applying high frequency power to perform glow discharge. Then, an a-Si layer containing H is deposited.

(C,) Problems to be Solved by the Invention However, when an a-Si5 photoreceptor is formed by the method described above, ■ In order for the a-Si photoreceptor to have sufficient photosensitivity, the photoreceptor substrate must be heated. Therefore, a-Si
The H content of the layer increases, and the electrical conductivity decreases to 10-
” The charge retention rate becomes large as it becomes about s/cm.The electric conductivity is increased by adding B (raw material gas: 8ilt).
, etc.), it will improve to some extent, but it will still only be about IQ-11 to 10-125/cs at most.

In addition to the problem of photoreceptor characteristics such as a-
In the 5i photosensitive manufacturing process, (1) the film formation rate is slow;

■ Inefficient use of raw material gas.

(2) A large amount of powdered 5i-H polymer is produced as a by-product and adheres to the photoreceptor substrate surface during deposition, causing deposition defects.

There are problems such as high cost and low yield.

In view of the above problems, an object of the present invention is to provide an electrophotographic photoreceptor with a good charge retention rate by limiting the composition of the a-Si photoreceptor, and also to provide a method for manufacturing the photoreceptor.

(Means for Solving the d1 Problems) The a-3i ill-sensitivity light of this invention has an integrated intensity of approximately 880 cm-' in the infrared spectrum of the photoconductive layer, and approximately a
The integrated intensity of 4oem-' ■The ratio of 2 is approximately 0.2 <(
Iz/II) <0.6, and is characterized in that the photoconductive layer of the a-Si photoreceptor is formed by electron cyclotron resonance method.

(In the e1 action infrared spectrum, a peak of 5i-H bond appears around 2000 cm-',
A peak of 5ilt appears near C1ll-'. In addition, in SiH2, absorption is observed only around 880c @ 5iI (!) when it exists alone, and approximately 880c when it exists in the form of a polymer ((Si11g)n).
Absorption is seen both around 0 cm-' and around 840C11-'.

In the case of an a-Si photoreceptor, 5iHz and (SiHz)n coexist, and it has been said that the photoreceptor characteristics such as electrical conductivity are influenced by the ratio of the two.

This ratio is 880 (Jl-
', the ratio of the integrated intensity (Jα(w)/wd呵) of 840a*-1 (intensity approximately around 840a*-')/r+(
The intensity around 880 cm-' can be used as an index, and this ratio can be calculated as approximately 0.2 < (It/It) < 0
．． By setting it to 6, the electrical conductivity etc.
Photoreceptor characteristics can be improved.

Figure 1 shows the integrated intensity ratio (lx/It) and electrical conductivity,
This is a diagram showing the relationship between bright conductivity and bright conductivity.
-bcIA/v, which is a good value.

In addition, when forming an a-Si photoreceptor, if electron cyclotron resonance method (hereinafter referred to as ECR method) is used, there is no need to heat the substrate, and the integrated intensity ratio can be within a good range.
-It becomes possible to form a Si photoreceptor.

(f) Embodiment FIG. 3 is a schematic diagram of an ECR deposition apparatus for forming an a-Si photoreceptor of the present invention.

The device includes a plasma chamber 1 that generates hydrogen plasma, and a-
It has a deposition chamber 2 in which the 3i layer is deposited. The plasma chamber 1 and the deposition chamber 2 communicate with each other through a plasma extraction window, and are evacuated by an oil diffusion pump and an oil rotary pump (not shown).

The plasma chamber 1 has a cavity resonator configuration, and the waveguides 4 to 2
．． A microwave of 45 (Jz) is introduced. The microwave introduction window 5 is made of a quartz glass plate through which the microwave can pass. H2 gas is introduced into the plasma chamber 1.

A magnetic coil 6.7 is arranged around the plasma chamber 1. The magnetic coil 6 generates a plasma generation magnetic field (875G), and the magnetic coil 7 generates a divergent magnetic field for drawing out the plasma generated in the plasma chamber 1 to the deposition chamber 2.

In order to form an a-3i photosensitive image using such an apparatus, the photoreceptor base 8 is first set approximately in the center of the deposition chamber 2. The photoreceptor base 8 is a drum-shaped member made of, for example, aluminum. Then, the plasma chamber 1. Deposition chamber 2 is evacuated, Hz gas is supplied to plasma chamber 1, and source gas (SiHt, C1, etc.) is supplied to deposition chamber 2.
Further, microwaves are introduced into the plasma chamber 1, and a magnetic field is generated by the magnetic coils 6.7. Then, the 11□ gas becomes plasma in the plasma chamber 1, and this plasma is drawn out from the plasma extraction window 3 to the deposition chamber 2, and the raw material gas such as SiH4 is turned into plasma. As a result, plasma of the source gas is deposited on the photoreceptor substrate 8. Since the photoreceptor substrate 8 is rotated by the support, a uniform a-3i layer is formed on the surface. Note that the photoreceptor base 8 is not heated.

A normal a-3t photosensitive photo is one in which three a-3i layers, a blocking layer and a surface layer of a photoconductive layer 9, are formed on a substrate. -3i
A layer is formed. FIG. 3 is a diagram showing the conditions for forming the a-5i layer, and under each condition shown in the figure, the blocking layer,
By this ECR method a photoconductive N2 surface layer is deposited.
- If a Si layer is formed, ■ Relatively low pressure (10-
A stable plasma can be generated at 10-'torr), suppressing secondary reactions of reactive species, suppressing the generation of powdery 5i-H polymer, etc., and forming a good a-Si layer. be able to.

■ The energy of the electrons is high, and the decomposition, excitation, and ionization of the introduced gas are significantly improved compared to conventional plasma CVD methods, increasing the film formation rate (approximately 23 μm/hr) and improving the utilization efficiency of the introduced gas. (about 49%).

■ A high-quality a-3i layer with high photosensitivity can be formed without heating the photoreceptor substrate 8 due to high-speed ion bombardment.
z) n I can be suppressed.

There is an advantage.

Note that control of the a-Si conductivity type is performed using conventional plasma CVD.
Similarly to the method, in the case of p-type, it is sufficient to introduce a source gas containing a group Ⅰ element such as B2H4, and in the case of n-type, a source gas containing a group Ⅰ element such as PII+ is introduced. For example, the a-Si photoreceptor formed under the conditions shown in FIG. 3 is of the p-type.

Next, the characteristics of the formed a-Si photoreceptor will be explained.

Figure 1 shows S+H1 and (SiHi
) is a diagram showing other characteristics of four points A to D having different absorption intensity ratios in the infrared spectroscopy spectrum, which is an index for showing the ratio with n. Absorption intensity ratio (Iz/b) is 0.2
B and C in the range of ~0.6 have good sensitivity and a charge retention rate that is higher than that of a formed by conventional plasma CVD equipment.
This is an improvement over the -5i illuminant, and when an image was formed using this a-5i5 photon, a high quality image without fogging etc. could be obtained. Also, from this figure, 0.2
It can be seen that in A and D outside the range of ~0.6, although the charge retention rate is improved, the sensitivity and residual potential are poor, making them undesirable for use.

A quantitative analysis of the amount of hydrogen in the a-Si layer with an absorption intensity ratio in the range of 0.2 to 0.3 revealed that it was 40 to 50 aL%. By controlling the amount of hydrogen within this range, the dark resistivity and bright conductivity of the photoreceptor can be made to have good values.

Furthermore, this method of forming an a-Si layer can be applied not only to electrophotographic photoreceptors but also to devices such as solar cells and image sensors.

(g1 Effect of the invention The electrophotographic photoreceptor of this invention has Sil+□ and (Sit(
Since the ratio with z)n is in a good state, the electrical conductivity and charge retention rate of the a-Si photoreceptor can be improved, and high-quality images can be formed. When an a-Si layer is formed using an ECR method, there is no need to heat the photoreceptor substrate, so the integrated intensity ratio (Iz/l+) can be kept at approximately 0.
2. 0.4, and a good photoreceptor as described above can be formed. In addition, the ECR method can improve the film formation speed and raw material gas utilization efficiency, and does not generate powdered 5t-H polymer, which reduces manufacturing costs and improves the yield of photoreceptors. can be done.

[Brief explanation of the drawing]

Figure 2 is a diagram showing the characteristics of photoreceptors with different integrated intensity ratios, and Figure 3 is a diagram showing the characteristics of a-Si using the ECR method.
FIG. 4, which is a schematic diagram of the deposition apparatus, is a diagram showing the conditions for forming the a-Si layer. a plasma chamber, a deposition chamber, a plasma extraction window, a four-wave tube, a microwave introduction window, and a light guide substrate.

Claims (2)

[Claims] (1) An electrophotographic photoreceptor in which the photoconductive layer is made of an amorphous silicon-based material, and the infrared spectrum of the photoconductive layer is approximately 880c.
The integrated intensity I_1 of m^-^1 is approximately 840 cm^-^
An electrophotographic photoreceptor in which the ratio of integrated intensity I_2 of 1 is approximately 0.2<(I_2/I_1)<0.6. (2) A method for manufacturing an electrophotographic photoreceptor, in which the photoconductive layer is deposited by an electron cyclotron resonance method.