JPS60128457A - Photoconductive member - Google Patents

Abstract

PURPOSE:To electrify both positive and negative polarities to a photoconductive member by providing semiconductor regions of alternately different conduction types along the interface near the boundary between the body of the photoconductive part consisting of an amorphous silicon layer provided on a base and the base. CONSTITUTION:A photoconductive member body 2 is laminated on a conductive base 1. The body 2 is formed of a photoconductive layer 3 consisting of a-Si provided to the base 1 and a surface coating layer 4 consisting of a-Si provided thereon. Semiconductor regions 6 of different conduction types are alternately formed along the interface direction near the boundary between the layer 3 and the base 1 by providing a-Si regions 5 of P type contg. the impurity of the IIIa group at prescribed intervals along the interface direction near the boundary between the layer 3 and the base 1. Positive electrification is made possible in the regions 5 and negative electrification is made possible except in the regions 5. The member having excellent electrifying power of both positive and negative polarities, high sensitivity up to the long wavelength region and a long life is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a photoconductive member that is sensitive to light (electromagnetic waves such as ultraviolet to visible, infrared, X-rays, and gamma rays).

[Technical background of the invention and its problems]

Photoconductive materials constituting photoconductive layers in solid-state imaging devices, electrophotographic photoreceptors, etc. have a high specific resistance in the dark (usually 10Ω or more) due to the purpose of their use and the purpose of the soil, and they have a high specific resistance when irradiated with light. It must have the property of reducing resistance.

Using electrophotography as an example, the principle and conditions necessary for a photoreceptor will be briefly explained. In electrophotography, when the surface of a photoreceptor is irradiated with light, pairs of electrons and holes are created, and one of these pairs neutralizes the surface charge. For example, when it is positively charged, it is neutralized by the electrons in the pair created by light irradiation. This is done by attracting black powder called toner, which is charged with a polarity different from that on the surface of the photoreceptor, from a developing device to the surface of the photoreceptor using Coulomb force. At this time, in order to prevent the toner from being attracted to the photoreceptor due to the charge of the toner even if there is no charge on the surface of the photoreceptor, an electric field is created between the photoreceptor and the developer in the opposite direction to the electric field due to the charge. A process of increasing the potential of the developing device is performed. The above is the principle, but next we will discuss the conditions necessary for a photoreceptor: firstly, the charge charged by corona discharge is retained until light irradiation, and secondly, the electrons and holes generated by light irradiation One example of this is that the -man neutralizes the surface charge without the pair recombining, and the other -man instantly reaches the photoreceptor support.

Conventionally used materials include amorphous chalcogenide. Amorphous chalcogenide is a material that can be easily made into a large area and has excellent photoconductivity, but its light absorption edge is from the visible to near the ultraviolet range, and its sensitivity to light in the visible range is low for practical purposes. In addition, it has low hardness and has a short life when applied to electrophotographic photoreceptors. It is also harmful to the human body. Further, there are problems such as a low softening point. Based on this, amorphous silicon (hereinafter referred to as a-8i) is a photoconductive material that has recently attracted attention.

This a-S i has a wide absorption wavelength range <, , punch
romatic and high sensitivity. Furthermore, it has high hardness, and when applied as an electrophotographic photoreceptor, it is expected to have a lifespan ten times longer than conventional ones. Furthermore, it is harmless to the human body, and when compared with single-crystal Si, it is an excellent material that has many advantages such as being inexpensive and easily obtained in a large area. Another feature of this a-81 is that p-n control can be easily achieved by adding impurities from Groups 1a and 1a of the periodic table. Therefore, when applied as a photoconductive member, either negative charging, positive charging, or both positive and negative charging is possible. First, when using it for negative charging, a-
8i is fine as is.

Because the hole mobility and I, ife Ti
This is because me is small and the conduction type is somewhat n-type. In addition, ■a-Si doped with group a impurities
If a layer consisting of A is provided between the photoconductive layer and the support, holes from the support to the photoconductive layer will be blocked, and the charging ability will be improved by adding A containing a group Ia impurity. -S
Positive charging is made possible by, for example, providing a layer consisting of i between the photoconductive layer and the support. Furthermore, it is conceivable to charge both positive and negative charges for purposes such as two-color copying and dual use as a printer and copying device. In that case, an insulating layer may be provided between the photoconductive layer and the support. However, if this layer is thick, carriers flowing from the photosensitive layer toward the support during light irradiation are also blocked, resulting in a high residual potential and, therefore, deterioration in repeatability.

Conversely, if the film thickness is made thinner, dielectric breakdown will occur during development.

For this reason, there is currently no material for both positive and negative charging that has good characteristics.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its objectives are to have excellent charging ability in both positive and negative charging, low residual potential, high sensitivity to long wavelength range, and long-term use. The above characteristics do not deteriorate even when used with
Therefore, it is an object of the present invention to provide a photoconductive member that has a long life and can be charged both positively and negatively.

[Summary of the invention]

In order to achieve the above object, the present invention includes a single support,
A photoconductive member main body having a photoconductive layer made of amorphous silicon provided on the support body and a metal fitting are provided, and the vicinity of the boundary between the photoconductive layer and the support body in the wooden body of the photoconductive member The structure is characterized in that semiconductor regions of different conductivity types are provided alternately along the interface direction, so that positive to negative charging is possible.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. Reference numeral 1 in FIG. 1 denotes a conductive support, on which a photoconductive member main body 2 is laminated. This photoconductive member body 2
consists of a photoconductive layer 3 made of a-Si provided on the support 1, and a surface coating layer 4 made of a-81 provided thereon. In addition, near the boundary between the photoconductive layer 3 and the support 1, there is a P-type a-8i containing group 1a impurities.
Regions 5 are provided at predetermined intervals in the interface direction,
As a result, in the vicinity of the boundary between the photoconductive layer 3 and the support 1, semiconductor regions 6 of different conductivity types are alternately present in the direction of the interface.

Considering the case where a charge is applied by corona discharge to a photoconductive member having the above layered structure, firstly, when a positive charge is applied, the support 1 in the P-type a-St region 5
Electrons are prevented from flowing into the photoconductive layer 3 from the side, allowing positive charging in this portion. However, in the region where Group 1a impurities are not present near the boundary between the photoconductive layer 3 and the support 1, the inflow of electrons is not blocked.
This part is not positively charged.

In addition, when a negative charge is applied, the hole mobility and LifeTime are small in the region near the boundary of the photoconductive layer 3 with the support and does not contain group 1ea impurities, and the conductivity type is somewhat n. Since it is shaped like a mold, holes are prevented from flowing into the photoconductive layer 3 from the support 1, and this portion can be negatively charged. However, since the inflow of holes is not blocked in the P-type a-3i region 5, this portion is not negatively charged. As described above, when the corona discharge is of positive polarity, this photoconductive member contains P containing Group 11a impurities.
When the type A-81 region 5 has negative polarity, the regions in which group 1a impurities are not present near the boundary with the support 1 of the photoconductive layer 3 are the regions of the support 1 of the photoconductive layer 3, respectively. Since carriers are prevented from flowing into the photoconductive layer 3 from the support 1 side near the boundary, both positive and negative charging is possible.

In order to improve the negative charging ability, as shown in FIG. Va
The n-type a-Si region 7 may be formed by adding impurities of the group A-Si.

Next, the outline of the film forming apparatus will be explained. 11 in Figure 3
is a vacuum reaction chamber, and an electrode 1 is placed inside this reaction chamber 11.
2, a support fixing device 13, a support 1, a heater 15 for keeping the temperature of the support constant, and an ion source 16 are accommodated.

17 is a gas supply device, and the gas to be used is introduced into the reaction chamber 11 from this gas supply device 17 through a pipe 18, and is exhausted by an exhaust device 19. In addition, 13.56 MHz high frequency power is applied to the electrode 12 from the RF power source 2O, thereby causing the electrode 12 in the reaction chamber 11 to
Plasma is generated between the fixing device 13 and the fixing device 13, and a film can be formed on the support l.

Next, a film forming method will be explained. First, the conductive support 1 is attached to the fixing device 13 in the reaction chamber 11, and the inside of the reaction chamber 11 is evacuated to 10 to 10 Torr using the exhaust device 19. At the same time, the temperature of the support 1 is increased to 100°C to 400°C.

First, the photoconductive layer 3 is prepared.

The gas used is a gas containing Si atoms, such as S.
iH, (silane), 5j2Ha (disilane), Si
A gas containing C (carbon) as a gas additive such as F, (silicon tetrafluoride), etc. A gas containing N (nitrogen) such as 0M4 (meth), C2H6 (ethane), C5Ha (butane), etc. NHs (ammonia) etc., 0 (oxygen)
As a gas containing 0. , N, 0 (nitrogen oxide), etc. In addition, gases containing Group 1a, such as B2H2 (digarane)
, BFs (boron trichloride), BCAa (boron trichloride), etc. are used to lightly dope the photoconductive layer with Group 1a (
Dope). The inside of the reaction chamber 11 is 0.1 to 1'
The exhaust speed of the exhaust system is adjusted so that the pressure is approximately 1'orr, and after waiting until a steady state is reached, a high frequency power of 13.56 MH2 is applied between the electrodes in the reaction chamber 11 to form a film.

Next, the application of electric power is stopped, the support 1 is taken out from the reaction chamber 11, a uniform mask t with a constant hole diameter and pitch is placed on the formed photoconductive layer 3, and the support body 1 is fixed again in the reaction chamber 11. It is fixed to the device 13.

Then, the inside of the reaction chamber 11 is evacuated by the exhaust device 19 to 10 to 10
After reducing the pressure to Torr, the 1i[a
Group ions are implanted into the photoconductive layer 3 near the boundary with the conductive support 1 . As a result, the P type a-8i region 5 shown in FIG. 1 is formed.

After that, after taking out the support 1 from the reaction chamber 11 and shifting the mask, the Va.
Group ions may be implanted, which results in the n
A type a-8i region 7 is formed, and the negative charging ability is improved.

Further, after forming the photoconductive layer 3 to a thickness of 10 to several μm, regions of different conductivity types are formed in the interface direction near the boundary between the photoconductive layer 3 and the support 1 using the same method as above. After the photoconductive layers 3 are made to exist alternately, the mask may be removed and the photoconductive layer 3 made of a-8i may be laminated again.

Furthermore, when ions are implanted in the above case, the same effect as with a mask can be obtained by scanning and continuing the ion source without using a mask.

Furthermore, it is also possible to produce photoconductive members without using an ion source. In that case, a mask is placed on the support 1 in advance, and high frequency power is applied to the region 5 consisting of a-81 containing the Ha group shown in FIG.
After that, the mask may be removed and a photoconductive layer 3 made of a-81 may be formed. In this case, even if the mask is shifted and a region (n-type a-3i region 7 shown in FIG. 2) consisting of a-8i containing group Ⅰa is deposited before forming the photoconductive layer 3, good.

By doing so, the negative charging ability is improved.

Next, the photoconductive member produced in this way is fixed in the reaction chamber 11, and a gas containing Sl atoms, for example, SiH, 5t2
A gas such as H6, SiF4, etc. and a gas containing C as an additive, such as CH4, CzHe, CsHa, etc., or a gas containing N, such as N2. Gas such as NH, or O
A gas containing, for example, 02. Introducing a gas such as N, 0, etc.
．． The exhaust speed of the exhaust system is adjusted to a pressure of 1 to 1.5'l'orr, and after a steady state is reached, the surface coating layer 4 is provided by applying high frequency power. This improves the characteristics. Note that this surface coating layer 4 may not be provided.

Next, an experimental example will be explained.

(Experiment Example 1) Support 1 heated to 300°C
Add the photoconductive layer 3 to SiH4 at a flow rate of 30 SCCM.

A film was formed for 10 minutes under the conditions of a reaction pressure of 0.2 Torr and a high frequency power of 50 W. Next, make a hole diameter of 20μ on support 1.
A mask with a pitch of 27 μm was applied, and B+ ions were injected from the ion source for 20 minutes.

Thereafter, the mask was removed, the temperature of the support 1 was raised to 300° C., and a photoconductive layer 3 was formed again under the conditions of a flow rate of 5 lH 4 at 80 SCCM, a reaction pressure of 0.4 Torr, and a high-frequency power of 100 W for 1 hour. Furthermore, the surface coating layer 4 was formed for 5 minutes under the following conditions: a flow rate of SiH4 of 50 SCCM%, a flow rate of CH4 of 250 SCCM, a reaction pressure of 0.5 Torr, and a high frequency power of 50 W. The total film thickness was 15 μm. The photoconductive member produced in this manner has a current flowing into the charger support 1 (drum) due to corona discharge of ±0.45 μc.
/cd, the positive charging capacity is 600V or more,
The negative chargeability was 400 V or more, and the potential retention rate after 15 seconds was 60% or more in the positive case and 5-0% or more in the negative case. Further, as a result of repeated use 10,000 times, there was no deterioration in characteristics such as charging ability and retention rate in both positive and negative charging, no increase in residual potential, and no surface deterioration. Furthermore, when continuous copies were made 30,000 times using this photoconductive member, good images were obtained in both positive and negative charging.

(Experimental Example 2) In Experimental Example 1, after implanting 1B ions, the mask was shifted and 2 P ions were implanted from the ion source.
After injecting for 5 minutes, a photoconductive layer 3 similar to that in Experimental Example 1 was formed. The produced photoconductive member had a negative chargeability of 600 V or more and a retention rate of 60% or more under the condition of an inflow current of -0.45 μC/-. As a result of image display, a clear image was obtained as in Experimental Example 1.

〔Effect of the invention〕

As explained above, according to the present invention, the photoconductive member body includes a support and a photoconductive layer made of amorphous silicon provided on the support, and the photoconductive member body has a photoconductive layer formed on the support. Semiconductor regions of different conductivity types are provided alternately along the interface direction in the vicinity of the boundary between the conductive layer and the support, resulting in a structure capable of being charged in both positive and negative polarities. It is also possible to provide a photoconductive member that has a low residual potential, has high sensitivity up to a long wavelength range, and does not deteriorate the above characteristics even after long-term use, and has a long life and can be charged both positively and negatively. It has excellent effects such as:

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention. FIG. 2 is a sectional view showing another embodiment of the invention, and FIG. 3 is a configuration diagram showing a film forming apparatus. DESCRIPTION OF SYMBOLS 1... Support body, 2... Photoconductive member main body, 3... Photoconductive layer, 4... Surface coating layer, 5... P type a-S
i region, 6...semiconductor 1 body region, 7...n type a-S
i area.

Claims (1)

[Scope of Claims] (11) A photoconductive member main body having a support and a photoconductive layer made of amorphous silicon provided on the support; A photoconductive member characterized in that semiconductor regions of different conductivity types are provided alternately along the interface direction in the vicinity of the boundary with the support body, so that the photoconductive member can be charged with both positive and negative polarities. (2) The photoconductive member according to claim 1, wherein the photoconductive member main body is constructed by providing a surface coating layer made of amorphous silicon on the surface of the photoconductive layer opposite to the base body. 3) The photoconductive member according to claim 1 or $2, characterized in that the photoconductive layer contains elements of Group 1a and Group Ⅰa of the periodic table. ) The photoconductive layer according to any one of claims 1 to 3, wherein the photoconductive layer contains at least one of the following elements: carbon, nitrogen, and oxygen. Member. (5) The photoconductive member according to claim 2, wherein the surface coating layer contains at least one of the following elements: carbon, nitrogen, and oxygen.