JPH0723962B2 - Drum type photoconductor manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to laminating a photosensitive semiconductor layer on a drum.

In the conventional plasma discharge method, the photoconductor used in the electrostatic copying machine is provided on a flat substrate. However, in the case of providing a semiconductor layer with a large thickness like a photoconductor, a flat substrate is not satisfactory in terms of forming the same film with a constant thickness.

Therefore, it is an object of the present invention to provide a method of forming a semiconductor layer of a photoreceptor with a uniform thickness.

Therefore, in the method for producing a drum-shaped photoreceptor of the present invention, a conductive substrate is produced from a cylindrical aluminum or its compound, and the cylindrical conductive substrate is formed in a plasma generation region in a cylindrical reaction furnace. A step of introducing a gas containing a silicide and a gas containing boron or indium into the plasma on the surface of the cylindrical conductive substrate while rotating the substrate to form a first semiconductor layer on the conductive substrate. Introducing a gas containing a silicide to form an intrinsic or substantially intrinsic second semiconductor layer over the entire circumference of the first semiconductor layer; the gas containing a silicide and the nitride gas or the carbide gas; And the step of forming a charge-transmissive insulator layer on the second semiconductor layer by introducing the above method, the coating film is provided on the conductive substrate.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the elements of an electrostatic copying machine to which the present invention is applied. That is, in FIG. 1A, a photoconductive semiconductor (1) is provided on a conductive substrate. After this, as shown in FIG. 1 (C), static electricity in the regions (6), (6 ') and (6 ") locally absorbed by the light (5) is discharged to the conductor (2). In addition, in the drawing, the negative electrons of the electric-hole pairs generated by photoexcitation recombine with the positive static electricity and neutralize it, thus allowing the static electricity to be selectively distributed on the semiconductor.

FIG. 2 shows the principle of an electronic copying machine provided with a photoconductive semiconductor layer using a rotating drum type semiconductor to which this principle is applied.

That is, the surface portion of the rotary drum is provided with a multi-layered structure of a P or N type semiconductor and an intrinsic or substantially intrinsic semiconductor as in FIG.

Further, the static electricity emitted from the static electricity generation source (8) is evenly distributed as shown in (3) in the energy band well-like semiconductor cluster or film on the upper surface of the drum. In addition, the light source (7) is used to produce objects (eg, printed paper surface).
The reflected light (5) from (11) passes through the slit (9) and illuminates the drum. Then, a photoelectromotive force is generated in the semiconductor in the irradiated surface region, and due to the recombination of the negative charges and the emission of the positive charges to the substrate conductor, the intensity of static electricity (4) is changed according to the reflected light (5). it can.

Further, on the surface of this rotating drum, black powder of carbon powder or a mixture thereof (particle size of 1.0 to 100 μ)) is distributed on the drum surface at the portion (12). Then, this powder adheres to the drum surface in proportion to the amount of static electricity. So-called "visualization" is performed.

Further rotation of this drum (speed is 1-10 seconds / revolution)
At the same speed as the above, the copy object, for example, a new paper (13) is moved in contact with the surface of the black powder to adhere the powder onto the copy object. After this, this paper (13) is printed and fixed to complete copying. The powder remaining on the surface of the drum is completely removed by the brush (14) and then reaches the first static electricity generation source.

FIG. 3 is an energy band diagram of a conventional non-junction type photoconductive semiconductor (1). In the drawing, static electricity (3) and conductor (2) on the back surface are provided, and electrons and holes are formed for light irradiation. However, since this semiconductor is a compound semiconductor such as CdS and is intrinsic, the Fermi level (22) is It exists in the center. Further, FIG. 3 (B) shows an energy band diagram in which static electricity is adsorbed on the surface of the semiconductor (1) to be in a stable state.

FIG. 4 shows a manufacturing apparatus using the plasma CVD method for manufacturing the drum of the present invention.

That is, the drum (42) arranged in the cylindrical reactor (50) capable of vacuuming has a diameter of 20 to 40 cm and a length of 25 to 50 cm. Rotated at speed. The surface of the drum is made of aluminum or its compound. Before the surface of the aluminum oxide is coated with a silicide gas, it is plasma sputtered in vacuum with Ar or Ar.
The surface on which the drum surface was formed was cleaned with a mixed gas of H ₂ and H ₂ to remove oxides or dirt. After this,
SiH ₄ is a silicide gas, the SiH ₂ Cl _2, SiCl ₄ or SiF ₄ is introduced from (40). Further, when forming a P-type semiconductor, B ₂ H ₆ and InCl ₃ which are trivalent impurities are simultaneously diluted and introduced with helium or the like. After this, plasma 1 ~
50MHz at high frequency or microwave frequency of 1-10GHz
A power (high-frequency output) of 100 W to 1 KW is applied, and as shown in FIG. 4 (B), between the drum (42) and the electrodes (47) and (47 ') which are arcuate to match the cylindrical shape of the drum. DC plasma CVD was performed while heating the drum to 200 to 400 ° C. so that an element containing silicon as a main component was deposited on the drum to generate plasma. Electrodes 47 and 47 'are in the reactor 50
Since it faces away from the inner wall of the drum 42 toward the drum 42, glow discharge is generated only near the surface of the conductive substrate on the drum 42. Therefore, the deposition of the silicide on the inner wall of the reaction furnace 50 is small, which is 1/10 or less as compared with the method using the simple glow discharge method, and the effective use of the material and the cost reduction can be achieved.
Furthermore, the introduction of B ₂ H ₆ and InCl ₃ was stopped, and an intrinsic or substantially intrinsic semiconductor layer was formed.

The reaction furnace contains 3 to 30% silicide gas, especially silane, and He 97 to 70%.
%, And when 0.1 to 5% of B ₂ H ₆ or InCl ₃ was introduced, the amount of helium as a diluent corresponding to that amount was reduced. Helium was the lightest of all gases, and had a thermal conductivity about three times higher than that of Ar, etc., and was a very preferable dilution gas for soaking in the reaction furnace.

Furthermore, He has an ionization voltage of 21 eV when it is ionized,
It was much larger than that of other gases, 12 to 15 eV, and as a result, it made a large contribution to sustaining the plasma state.

Further, in order to make the formed film not a semiconductor but a semi-insulator, ammonia was similarly added. Then Si ₃ N
_{When 4-} x (0 <x <4) is formed and nitrogen is added 10 to 50 atomic%, the film has Eg of 2.0 to 3.0 eV and silicon of 1.0 to 1.8 eV.
Can be made larger and the abrasion resistance is also improved. As a result, the electrostatic copying machine of the present invention is added with 10 to 50 atomic% of nitrogen, not with the conventionally known simple silicon, and the amount of nitrogen added is particularly large on or near the surface of the semiconductor where the static electricity is adsorbed. And

Thus, as shown in FIG. 5, a P-type semiconductor (21), an intrinsic or substantially intrinsic semiconductor (23) is formed on the conductor substrate (2).
To form a semiconductor layer (1). An insulating or semi-insulating film (26) with a thickness that allows a current to flow on this upper surface (26) Here, silicon nitride is gradually laminated in the range of 10 to 100 A (angstrom), particularly 30 to 50 A (angstrom), and a photoconductive semiconductor or semi-insulator is formed. Layered. The semiconductor cluster (5
0) was produced in the same reaction furnace so as to form an energy well type. Further, a second insulating or semi-insulating film (27) having a thickness allowing an electric current to flow is formed on the upper surface thereof by the same manufacturing method as in (26). 50 semiconductor clusters (50)
It is a lump-shaped semiconductor having a diameter of A (angstrom) to 5 μm, and the respective clusters are electrically insulated from each other. Average film thickness 50-2000A (angstrom)
This cluster, having a thickness of, may deposit only silane on the film (26), or 0.1-10
It may be a lower nitride obtained by nitriding the outer periphery of the cluster to which atomic% of nitrogen is added. In any case, even if electrostatic charges are once stored in the well (50) having the energy band lower (narrower) than the semiconductor surface, it is necessary to have an insulating property so as not to diffuse in the plane direction. In this sense, it was effective to make the semiconductor a cluster structure and to add nitrogen to make its periphery insulating.

Further, in the present invention, an insulator having a thickness capable of passing a current on the surface of the cluster or film of the semiconductor, here, silicon nitride (Si ₃ N ₄ ) is used as the barrier layer (27) to have a thickness of 30 to 100 A (angstrom). Formed. This silicon nitride has an energy band width of 5.0 eV, which is harder and more abrasion resistant than silicon oxide, and has a thickness of 30 to 10
Even if it is as thick as 0 A (angstrom), current can flow. Therefore, it has a feature that it has a longer life than a silicon oxide protective film.

In the present invention, the introduction of silane is stopped in the reaction furnace of FIG. 4 and only ammonia is introduced to form a plasma, and the surface of this semiconductor or semi-insulator is nitrided by a solid phase-gas phase reaction to form an insulating film (27 ) May be formed. This protective film (27)
May be silicon carbide. In the case of silicon carbide, a carbide gas such as methane, ethane or propane is introduced.

According to the present invention, the semiconductor layer can be provided thickly and uniformly on the substrate. Furthermore, since the semiconductor or semi-insulating film on this drum was formed by the low pressure CVD method using DC plasma while rotating the drum, the loss due to the adhesion of the material to the wall of the reaction furnace was reduced. It has characteristics and is extremely important industrially. Furthermore, if a conductive substrate of aluminum or its compound is used as the power supply electrode,
Plasma sputtering occurs on the conductive substrate, and the surface of the conductive substrate can be cleaned by plasma sputtering.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the principle of localized electrostatic charging according to the present invention. FIG. 2 is a schematic diagram showing the principle of a drum type electrostatic copying machine. FIG. 3 is an energy band diagram of a conventional semiconductor for a copying machine. FIG. 4 is a schematic diagram showing the principle of a manufacturing apparatus using the plasma CVD method for producing the photoconductor of the present invention. FIG. 5 is a diagram showing the energy band structure of the photoconductor of the present invention.

Claims (1)

[Claims] 1. A conductive substrate is made of cylindrical aluminum or a compound thereof so as to serve as one electrode for generating plasma in a reaction furnace, and conductive is provided on the side of the conductive substrate with respect to the inner wall of the reaction furnace. An electrode is arranged opposite to the surface of the conductive substrate, plasma is generated between the conductive substrate and the electrode,
Forming a first semiconductor layer on the conductive substrate by introducing a gas containing a silicide and a gas containing boron or indium into the plasma while rotating the conductive substrate; and including a silicide. Introducing a gas to form an intrinsic or substantially intrinsic second semiconductor layer on the first semiconductor layer;
A process for producing a drum type photosensitive member, comprising the steps of introducing a gas containing a silicide and a carbide gas to form a charge permeable insulator layer on the second semiconductor layer.