JPS6017452A - Manufacture of copying machine - Google Patents

Abstract

PURPOSE:To execute at a high speed a transfer plural times by the same charge, by constituting so that a cluster of a semiconductor or a layer of a film is placed between two (half) insulating films, and forming a layer for catching and accumulating a charge. CONSTITUTION:A semiconductor layer 1 consisting of a P type semiconductor 21 and an intrinsic semiconductor 23 is formed on an electric conductor substrate 2, and on this upper face, a (half) insulating film 26 (example: a silicon nitride film) of a thickness which is capable of making a current flow is laminated, and it is formed as a layer of a photoconductive semiconductor or a half insulator. On this upper face, a cluster 50 of a semiconductor is manufactured so as to constitute a well type in respect of energy, and also, on its upper face, the second (half) insulating film 27 is manufactured. A few carriers in electron hole pair generated by an optical irradiation 20 are recoupled to the injected charge. Or a powder 53 is attracted by this electrostatic charge and attracted to the surface of the insulating film 27 in proportion to quantity of the electrostatic charge. Also, it is unnecessary to accumulate the electrostatic charge again at every time of printing, and with respect to a copying machine which executes printing plural times, a desirable result is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for fabricating a semiconductor on a selectively electrostatically charged plate or drum in a copying machine.

The present invention is particularly effective when copying and printing the same pattern many times using an electrostatic copying machine. It is characterized by laminating layers that capture and store charges.

The present invention has a structure in which a semiconductor cluster or film layer is sandwiched between two insulating or semi-insulating films to form a layer for trapping and accumulating charges, and the charges accumulated in such layers adsorb black powder. The adsorbed powder is transferred to the object to be copied. After that, the same charge is used to attract the black powder again and transfer it to the object to be transferred, so that multiple copies can be made at high speed using the same charge.

The present invention is intended to store patterns in a non-volatile manner on a substrate or drum, and to perform copying using this stored information.

The present invention provides a first layer of P or N type semi-quadratures on a conductive substrate, and a second layer of pure or substantially intrinsic semiconductor or semi-insulator is formed on the layer. be. The present invention provides a charge trapping layer formed by sandwiching semiconductor clusters or films sandwiched between insulating or semi-insulating films having a thickness that allows electrostatic charge to flow on such a semiconductor or semi-insulating layer, and charges the layer. It is characterized by recombining static charges and selectively photo-excited charges, and discharging the static charges or photo-excited majority carriers to the conductor on the back surface.

Conventionally, electrostatic copying machines have used intrinsic group II- and VI compound semiconductors in layers that selectively charge static electricity using the photoelectric effect. However, in this method, the material itself is a pollutant, and in addition to being printed with carcinogenic substances, the charge generated by light irradiation increases the contrast with the already charged charge (S/ They were not necessarily satisfied with the idea of increasing the N ratio.

Therefore, the present invention provides I-
It is characterized in that an N junction or an I-P junction is installed to form an internal electric field in the semiconductor, further increasing the S/N ratio, and that silicon or its compound, which is a non-polluting substance, is used.

Examples thereof 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. In FIG. 1(A), a photoconductive semiconductor (1) is provided on a conductive substrate. As shown in FIG. 1(B), static electricity (3) was uniformly distributed thereon. In the drawings, positive charges are emitted from an electrostatic source and deposited on the charge deposited layer of the present invention. Furthermore, after this, as shown in FIG. 1(C), a region (6) where the light (5) is locally adsorbed.

The static electricity of (6'') and (6') is released to the conductor (2).

In addition, in the figure, negative electrons of the electric/pole pairs generated by photoexcitation recombine with this positive static electricity and neutralize it. In this way, it was possible to selectively distribute static electricity on the semiconductor.

FIG. 2 shows the principle of a semiconductor electronic copying machine with a rotating drum structure to which this principle is applied.

That is, the surface portion of the rotating drum has a multilayer structure of a P- or N-type semiconductor and an intrinsic or substantially intrinsic semiconductor, and on top of this is a layer forming a well shape in terms of energy band, as shown in FIG. It is provided.

The static electricity emitted from the static electricity generation source (8) is uniformly distributed within the well-shaped semiconductor cluster or film on the upper part of the drum as shown in (3). Further, a light source (7) emits reflected light (5) from an object (for example, a printed paper surface) (11), which passes through a slit (9) and irradiates the drum.

Then, a photovoltaic force is generated in the semiconductor in the irradiated surface area, and due to the recombination of the negative charges and the release of the positive charges to the substrate conductor, the intensity of the static electricity (4) changes according to the reflected light (5). can.

Furthermore, black powder of carbon powder or a mixture similar to carbon powder (particle size of 1.0 to 100 μm) is distributed on the surface of the rotating drum at the portion (12).

This powder then adheres to the drum surface in proportion to the amount of static electricity. Perform so-called "visualization".

Further, an object to be copied, such as a new piece of paper (13), is moved in contact with the surface of this black powder at the same speed as the rotation of this drum (speed is I~10 seconds/rotation), and this powder is transferred onto the object to be copied. Let it adhere to. Thereafter, this paper (13) undergoes printing and fixing to complete the copy. After the powder remaining on the surface of the drum is completely removed by a brush (14), it reaches the first static electricity generation source (8).

FIG. 3 is an energy band diagram of a conventional non-junction type photoconductive semiconductor (1). In the drawing, static electricity (3),
An m-plane conductor (2) is provided, and electron-ball pairs are formed by light irradiation, but since this semiconductor is a compound semiconductor such as CdS and is intrinsic, the Fermi level (22) exists in the center. There is. Furthermore, an energy band diagram in which static electricity is attracted to the surface of this semiconductor (2) and a stable state is obtained is shown in FIG. 3(B).

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

That is, a drum (4) disposed in a vacuum capable reactor (50)
2) had a diameter of 20 to 40 cm and a length of 25 to 50 cm, and this drum (42) was rotated at a speed of 08I to 1 time/sec. The surface of this drum is made of aluminum or its compound, and the aluminum oxide on the surface is coated with plasma sputtering in a vacuum or with a mixed gas of Ar and 11□ before being coated with silicide gas. The forming surface was cleaned to remove oxides or dirt. Silicide gas, e.g. 5ill+, 5ill
□C1z + S s Cl 4 or SiF4 (4
0). Furthermore, when forming a P-type semiconductor, B2116. At the same time, InCl+ was diluted with helium and the like and introduced. After this, the plasma was heated at a frequency of 1 to 50 MIIz, 1 to 10 GIlz, and a power of 100 W to IKH (high frequency output) was applied.
As shown in FIG. 4(B) where the longitudinal cross-sectional view of FIG. 4(A) is shown.
, drum (42) and electric IM (47) , (47°)
The drum was heated at 200 to 50 ml to cause plasma formation between the drum and the element mainly composed of silicon.
DC plasma CVD was performed while heating to 00°C. Further, the introduction of B2O2 and InCl3 was stopped to form an intrinsic or substantially intrinsic semiconductor.

The inside of the reactor is filled with silicide gas, especially silane, at 3~30χ, He
97 to 10%, and further B 2II or In
When introducing 0.1 to 5x of Cl3, the amount of helium, which is a diluent corresponding to the amount of Cl3, was reduced. Helium is light in all gases, and its thermal conductivity is about three times greater than Ar, etc., making it an extremely preferable diluent gas for equalizing heat in the reactor.

Furthermore, when lle is ionized, the ionization voltage is 21 eV.
This value was extremely large compared to 12 to 15 eν for other gases, and as a result, it made a large contribution to the continuation of the plasma state.

Furthermore, in order to make the formed film a semi-insulator rather than a semiconductor, ammonia was similarly added. Then 5i
3Nn-x (0<X<4) is formed, and nitrogen is
When 50 atoms χ are added, the film has an Eg of 2.0 to 3. O
eV could be made larger than the 1.0 to 1°8 eV of silicon, and in addition, wear resistance was improved. As a result, the electrostatic copying machine of the present invention is not made of the conventionally known simple silicon, but has nitrogen added to Iθ~50 atoms, and in particular, a large amount of nitrogen is added to the surface of this semiconductor where static electricity is attracted or its vicinity. did.

Thus, as shown in Figure 5 (^), the conductor substrate (2)
Second, a semiconductor layer (1) consisting of a P-type semiconductor (21) and an intrinsic or substantially intrinsic semiconductor (23) was formed. Next, an insulating or semi-insulating film (
26) Here, silicon nitride is 10 to 100 people, especially 30 to 5
The layers were successively stacked to form photoconductive semiconductor or semi-insulator layers. A semiconductor cluster (50) was formed on this upper surface in the same reactor so as to form a well-shaped structure in terms of energy. Further, a second insulating or semi-insulating film (27) having a thickness sufficient to allow current to flow was formed on the upper surface thereof by the same method as in (26). The semiconductor clusters (50) are bulk semiconductors having a diameter of 50 to 5μ, and the clusters are electrically insulated from each other. Average film thickness is 50
This cluster with a thickness of ~2000 nm may be deposited with silane alone onto the film (26), or the outer periphery of the cluster may be nitrided with 0.1 to 10 atoms of nitrogen added to the silicon. It may also be a lower nitride. In any case, even if electrostatic charge (1:j) is accumulated in the well (50) that has a lower (narrow) energy hunt than the semiconductor surface, it must have insulating properties to the extent that it will not diffuse in the surface direction. In this sense, it was effective to form the semiconductor into a cluster structure and add enough nitrogen to make the periphery insulating.

Furthermore, in the present invention, an insulator, here silicon nitride (Si3N4), is formed to a thickness of 30 to 100 layers as a barrier layer to allow current to flow on the surface of the semiconductor cluster or film. This silicon nitride has an energy band of 5
．． OeV, which is harder and has better wear resistance than silicon oxide, and can conduct current even if the thickness is 30 to 100 mm thick. Therefore, it has a feature that it has a longer lifespan than a silicon oxide protective film.

In the present invention, the introduction of silane is stopped in the reactor shown in Fig. 4, and only ammonia is turned into plasma by four people, and the surface of this semiconductor or semi-insulator is nitrided by an in-phase-vapor phase reaction to form an insulating film (29 ) may be formed.

This protective film (27) may be made of silicon carbide.

FIG. 5 (8) thus formed shows the case where the minority carriers in the electron-ball pair generated by the light irradiation (20) recombine with the injected charges. Further, FIG. 5(B) shows an energy band diagram when positive electrostatic charges are accumulated and become nonvolatile. In this case, the powder (53) is attracted to this static charge, and the insulating film (2) is proportional to the amount of static charge.
7) Adsorbs to the surface.

In the semiconductor layer having the structure shown in FIGS. 5(8) and 5(B), there is no need to accumulate static charge again each time printing is performed, and favorable results can be obtained for a copying machine that prints multiple times.

FIG. 5(C) shows another embodiment of the present invention. Similar to FIG. 5(B), this drawing shows a semiconductor classif or film (50
), and electrostatic charge is accumulated in this well, but since the films (28) and (29) sandwiching the well were fabricated by plasma CVD, the edge of the energy band (edge) is soft. In this case, adjust the amount of nitrogen added and
Since it can be set to 3 to 4 eV, the coating (28),
Even when (29) was thickened by 30 to 500 people, it still had photosensitivity to light irradiation.

As is clear from the above explanation, the present invention is based on the conventional CdS
Compared to electrostatic copying machines that use compound semiconductors such as , etc., the semiconductor used as the main component is silicon, which is cheaper. Nitrogen was added to the semiconductor, especially at or near its surface, to make it hard and improve its wear resistance, and to prevent electrostatic leakage by making the semiconductor semi-insulating. P near the conductor board or drum
By providing a type semiconductor and creating an I-P junction, an internal electric field is generated and the S/N ratio (surface potential is 100 to 150 V).
and above).

In the embodiments of the present invention, cases where positive static electricity is applied are mainly shown. However, when charging with negative static electricity, it is sufficient to determine the conductivity type of the first semiconductor layer on the conductor whose junction is I-N, and the relationship is of completely opposite sign.

Furthermore, coating of the semiconductor or semi-insulating material on this drum is performed using a reduced pressure C using DC plasma while rotating the drum.
Since the VD method was used, it has the characteristics of reducing loss due to material adhesion to the walls of the reactor, and we believe that it is extremely important industrially.

[Brief explanation of the drawing]

FIG. 1 shows the principle of local electrostatic charging that will become clear in the present invention. FIG. 2 shows the principle of an electrostatic copying machine with two drums. FIG. 3 shows an energy hand diagram of a conventional semiconductor for copying machines. FIG. 4 shows the principle of a manufacturing apparatus using the plasma CVD method for manufacturing the copying machine of the present invention. FIG. 5 shows an energy hand diagram of a semiconductor for an electrostatic copying machine having a well-type energy hand structure according to the present invention. 398- Test 1 (2) cum 2 (2) (A

Claims (1)

[Claims] 1. Forming a photoconductive semiconductor or semi-insulating layer on a conductive substrate or drum, and forming semiconductor clusters or films on the semiconductor layer as a layer for trapping and storing charge. and, after the step, forming a layer having a large energy band 11 on the semiconductor cluster or film so that the cluster or film constitutes an energetic well shape. A method of manufacturing a copying machine. 2. In claim 1, the semiconductor cluster or film of the layer for trapping and accumulating charges is mainly composed of silicon, and an insulating or semi-insulating film of a silicon compound is provided with the layer sandwiched therebetween. A method for manufacturing a copying machine characterized by: 3. In claim 1, the photoconductive semiconductor layer is Si having a non-single crystal structure, S+Jt-x(0<za<
4) +St(:+-*(0<X4) or SiO□-
1. A method for manufacturing a copying machine, characterized in that x (0<X<2) is formed by laminating them by a plasma CVD method.