JPH0687404B2 - Image pickup tube and its operating method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup tube and a method of operating the same, and more particularly to a photoconductive material having a blocking contact with significantly improved sensitivity while maintaining good photoresponse characteristics. The present invention relates to an imaging tube made of a film and a method of operating the same.

[Conventional technology]

As already known, the target used in the photoconductive image pickup tube has a structure in which injection of charges from the signal electrode side and the electron beam scanning side is blocked, that is, a so-called blocking target (for example, Japanese Patent No. 902189). There is a so-called injection type target having a structure in which electric charges are injected from both the signal electrode side and the electron beam scanning side or one of them.
Among them, the blocking target has a feature that the afterimage can be made small, but a gain having a sensitivity higher than 1 has not been obtained so far because it has no amplifying action in the photoconductive film.

On the other hand, in the injection target, since more electrons than the number of incident photons can be taken out to the external circuit in principle, there is a possibility that the gain is higher than 1 and the sensitivity is increased. High-sensitivity image pickup tube (Patent No.
No. 571503) or a high-sensitivity image pickup tube target provided with an electron injection recombination layer for injecting scanning electrons and recombination of scanning electrons and holes on the beam scanning side of the photoconductive layer (Japanese Patent Application No. 60-
No. 140288) has been proposed.

[Problems to be solved by the invention]

However, in all of the above-mentioned conventional techniques in which the sensitivity of the photoconductive type image pickup tube target is increased to a gain larger than 1, all of the scanning electrons are injected into the image pickup tube target.
In principle, there was a problem that the effective storage capacity of the target increased and the afterimage increased.

Further, in the image pickup tube having the "semiconductor target plate" described in the above-mentioned Japanese Patent No. 571503, the average of scanning electrons reaching the p-type single crystal semiconductor layer reaches the signal electrode through the n-type single crystal semiconductor layer. The transit time is Tt, the average lifetime of electrons in the p-type single crystal semiconductor layer is Tn, and the scanning electron beam is 1
When the pixel scanning time is Te, there are restrictions such as the requirement of Tt <TnTe. Furthermore, it is difficult to obtain a good quality single crystal semiconductor substrate, and Si single crystal is used as a single crystal substrate. When it is used, since the specific resistance of the substrate is low, the np structure has to be separated into a mosaic shape as described in the above-mentioned patent publication, which is not preferable for improving the resolution of the image pickup tube.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate these conventional problems, and provide an image pickup tube having a low afterimage, high resolution, and significantly improved sensitivity, and an operating method thereof.

[Means for solving problems]

The above object is achieved by using an amorphous semiconductor layer having a charge multiplication function in a photoconductive target portion having a blocking structure.

Further, it is achieved by applying an electric field which causes a charge multiplication effect in the amorphous semiconductor layer to the target portion to operate the image pickup tube.

The present inventors have discovered that when a strong electric field is applied to an amorphous semiconductor layer mainly composed of Se, a charge multiplication action occurs inside the amorphous semiconductor layer. The confirmation of such a multiplication phenomenon in an amorphous semiconductor was made for the first time by the present inventors.

FIG. 2 is a principle configuration diagram of the target portion of the image pickup tube according to the present invention. A transparent substrate 21, a transparent electrode 22, a photoconductive film 24 made of an amorphous semiconductor layer, and an electron injection blocking layer 25 are shown.

When sufficient rectifying contact cannot be obtained between the transparent electrode 22 and the photoconductive film 24, it is also effective to interpose the rectifying contact auxiliary layer 23 to enhance the function of the rectifying contact.

By utilizing the phenomenon that a charge multiplication effect occurs in the amorphous semiconductor layer when a strong electric field is applied to the amorphous semiconductor layer, and by making the target structure to effectively generate such an operation, Gain is 1 without increasing afterimage
An image pickup tube having a higher sensitivity can be obtained.

Particularly, when the photoconductive film is formed of an amorphous semiconductor layer containing selenium as a main component, the electric field region in which the charge multiplication effect occurs is at least 5 × 10 ⁷ V / m to 2 × 10 ⁸ V / m. In the range of m, it is possible to obtain a charge multiplication effect suitable for the image pickup tube.

FIG. 1 shows an example of the principle configuration of an image pickup tube according to the present invention.

The image pickup tube uses a target portion composed of a transparent substrate 1, a transparent electrode 2, and a photoconductive film 3, and a group of electrodes 4, 9 and 10 for emitting, accelerating and deflecting and focusing an electron beam 6 are placed in a glass casing 5. It is created by vacuum-sealing.

The electrons emitted from the cathode 4 are accelerated by the voltage applied to the accelerating electrode 9 and are deflected and focused by the voltage applied to the deflection focusing electrode 10, and become the electron beam 6 to scan the surface of the photoconductive film 3. . In the portion scanned by the electron beam, a closed circuit is formed with the external resistance 7 and the external power source 8 via the electron beam and the transparent electrode 2, and the photoconductive film 3 has a negative potential on the electron beam scanning side. It is charged in the direction to the external voltage. When the light 11 is irradiated in this state, the light transmitted through the transparent substrate 1 is absorbed by the photoconductive film 3 to generate photocarriers. The photocarriers are separated by the electric field in the photoconductive film 3 determined by the external power supply 8 and travel in the photoconductive film 3. Since the image pickup tube is normally used in the electric field arrangement shown in the figure, holes of the photocarriers travel to the electron beam scanning side and electrons travel to the transparent electrode 2 side, and the photoconductive film 3 is charged as described above. The potential difference between the both ends of is reduced.

When the electron beam 6 is scanned next, the photoconductive film 3 is charged again so as to compensate for the decrease in the potential difference, and the current flowing through the external resistor 7 at this time is taken out as a signal.

In the above process, if the electric field applied from the outside is sufficiently high, the photocarriers traveling in the photoconductive film 3 are strongly accelerated to obtain high energy and generate a new photocarrier pair by the energy. And the number of this optical carrier increases avalanche. Therefore, in this case, as compared with the case where the number of photocarriers is not multiplied, the decrease in the potential difference due to the above process becomes larger even for the light of the same intensity, and accordingly the current flowing in the process of recharging becomes larger. That is, it means that the signal sensitivity is increased.

By the way, when a strong electric field is applied to the amorphous semiconductor layer to cause a charge multiplying effect inside, the function of rectifying contact, that is, the hole injection blocking becomes insufficient, or white scratches easily occur. Alternatively, there is a drawback that the electron injection blocking function from the scanning beam becomes insufficient and the dark current increases to deteriorate the image quality. These drawbacks can be solved by adding a specific substance into the amorphous semiconductor layer to control the electric field distribution in the amorphous semiconductor layer as described below.

First, the present inventors have found that in order to enhance the hole injection blocking function and suppress the generation of scratches, at least a part of the amorphous semiconductor layer containing Se as a main component is positive in the amorphous semiconductor layer. It has been found that it is effective to include a substance that forms a hole trap level. Further, as a substance that forms a hole trap level in such an amorphous semiconductor layer, Li, Na, K, Mg, Ca, Ba, Tl
And at least one selected from the group consisting of fluorides thereof and fluorides of Al, Cr, Mn, Co, Pb and Ce is extremely effective. Of these, for fluoride, LiF, NaF, Mg
F ₂ , CaF ₂ , BaF ₂ , AlF ₃ , CrF ₃ , MnF ₂ , CoF ₂ , PbF ₂ , Ce
It may have a stoichiometric composition such as F ₂ , TlF or KF, or may have a composition ratio deviating from them. As a result of further detailed examination, it is not necessary that the substance that forms the hole trap level in such an amorphous semiconductor layer be distributed at a uniform concentration in the film thickness direction of the photoconductive film. However, it may have a change in concentration, or it may be contained only in a part of it, especially when added to the light incident side,
Since the electric field near the electrode interface can be relaxed without impairing the charge multiplication function, it was revealed that the effect is remarkable.

What is important is a blocking structure, and at least a part of the amorphous semiconductor layer forming the photoconductive film, which forms a hole trap level in the amorphous semiconductor layer, at least. To include one.

Fig. 5 shows that LiF is added to a part of the amorphous semiconductor layer mainly composed of Se.
FIG. 3 shows the occurrence of scratches in the target containing 000 ppm by weight in comparison with the target in which LiF was not added. As is clear from the figure, by including LiF in at least a part of the amorphous semiconductor layer, the electric field in the photoconductive film is controlled without impairing the charge multiplication effect, and the occurrence rate of scratches is significantly increased. It is clear that it can be reduced.

The effect of adding the substance that forms the hole trap level in the amorphous semiconductor layer is not sufficient when the added amount is small, and the electric field in the amorphous semiconductor layer when the added amount is too large. Fluctuates easily and may cause seizure. Therefore, the local concentration of the above additive in the film thickness direction in the amorphous semiconductor layer is
It is desirable that the content is 20 ppm by weight or more and 10% by weight or less.

Furthermore, when an electric field strong enough to cause a charge multiplication effect inside is applied to an amorphous semiconductor layer containing Se as a main component, the inventors of the present invention used an amorphous material in order to enhance a blocking function against a scanning electron beam. It has been found that it is effective to make at least part of the semiconductor layer contain a substance that forms an electron trap level in the amorphous semiconductor layer. According to this method, the film thickness of the scanning electron beam side blocking layer can be increased to reduce the current, it is not necessary to strengthen the blocking function for the scanning electron beam, and the afterimage can be increased to deteriorate the image quality. Absent. In addition, good dark current characteristics could be obtained without impairing the charge multiplication effect.

Such substances that form an electron trap level in the amorphous semiconductor layer include copper oxide, indium oxide, selenium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, gallium fluoride, indium fluoride, Zn, Ga, In, Cl,
It was revealed that at least one selected from the group consisting of I and Br was extremely effective.

Here, regarding oxides and fluorides, CuO, In ₂ O ₃ , Se
It may have a stoichiometric composition such as O ₂ , V ₂ O ₅ , MoO ₃ , WO ₃ , GaF ₃ or InF ₃ or may have a composition ratio deviating from them. .

As a result of further detailed investigation, the inventors of the present invention have found that adding a substance that forms an electron trap level in such an amorphous semiconductor layer in the vicinity of the electron beam scanning side does not impair the charge multiplication function. Since the electric field near the electron beam scanning side can be relaxed, its effect is remarkable, and the added substance does not necessarily have to be distributed at a uniform concentration in the film thickness direction of the photoconductive layer. , It became clear that it does not matter if there is a change in concentration. When the concentration of the substance forming the electron trap level added to at least part of the thickness direction of the amorphous semiconductor layer mainly containing Se is low, the effect of the present invention is not sufficient, and If it is too large, seizure may occur easily.

Therefore, it is desirable that the local concentration in the thickness direction of the amorphous semiconductor layer of the substance forming the electron trap level added to the amorphous semiconductor layer is 20 wt% or more and 10 wt% or less.

The value of the addition concentration is the total value of the addition amounts of the respective addition substances when the substances to be added are plural kinds. Furthermore, at the same time when the substance that forms the electron trap level is added, at least a portion near the electron beam scanning side is
It was clarified that the effect can be further enhanced by forming a layer containing at least one of As and Ge.

Table 1 shows that 2000 parts by weight of indium oxide is applied to a part of the amorphous semiconductor layer mainly composed of Se to which the present invention is applied and which is near the scanning side.
FIG. 3 shows the dark current characteristics of a target portion (I) containing 38.8% by weight of m and As and the dark current characteristics of a target portion (II) to which the present invention is not applied.
Hereinafter, in the present invention, the concentrations of the substances added to the amorphous semiconductor layer are all represented by weight ratio. As is clear from the table, when the present invention is applied, it is clear that the electric field in the target portion can be controlled and the dark current can be greatly reduced without impairing the charge multiplication effect.

The above-described means for adding a substance that forms a hole trap level in the amorphous semiconductor layer and means for adding a substance that forms an electron trap level can be used in combination.

Further, FIG. 6 shows a target applied voltage for obtaining a gain of 1 or 10 in a target portion of an image pickup tube using an amorphous semiconductor layer mainly composed of Se having different film thicknesses in a photoconductive film, It is a diagram showing the relationship between the dark current and the film thickness when the target voltage is applied. From the figure, it can be seen that when the film thickness of the amorphous semiconductor layer becomes 0.5 μm or less, the dark current sharply increases. Therefore, the film thickness of this amorphous semiconductor layer is preferably 0.5 μm or more.

On the other hand, as the film thickness increases, the target applied voltage required to obtain a gain greater than 1 becomes high, and a ripple pattern (hereinafter referred to as “ripple phenomenon”) is likely to occur around the periphery of the screen. As described above, since the abnormal phenomenon is likely to occur when the applied voltage is 700 V or more, it is understood from practical use that the thickness of this amorphous semiconductor layer is 10 μm or less.

In addition, a method of reducing the incidence of scratches by incorporating a substance that forms a hole trap level and / or a substance that forms an electron trap level in the amorphous semiconductor layer may be combined. Furthermore, the photoconductive film does not necessarily have to be a single layer of an amorphous semiconductor layer, and it is different from that having a charge multiplication function.
The amorphous semiconductor layer of at least one kind may be deposited, or the crystalline semiconductor layer and the amorphous semiconductor layer may be deposited. What is needed is a whole film of an amorphous layer mainly composed of Se in an image pickup tube which is used by causing a multiplication of charges inside a photoconductive film containing at least an amorphous semiconductor layer mainly composed of Se. The thickness is to be 0.5 μm or more and 10 μm or less.

By the way, when an amorphous semiconductor material mainly composed of Se is used for the amorphous semiconductor layer, a long wavelength side limit of incident light capable of absorbing incident light to generate photocarriers, that is, electron-hole pairs Is limited by the energy gap of amorphous Se.
Further, amorphous Se has a property that a part of electron-hole pairs generated by absorbing incident light is separated by an electric field and recombined before disappearing before becoming a signal current. This phenomenon becomes more remarkable as the incident light has a longer wavelength, and this tendency still remains even in a strong electric field region where a charge multiplication effect occurs in the amorphous Se film.

It has been found that the following two means are effective for solving these problems.

First of all, according to the present inventors, when at least one of Te, Sb, Cd, and Bi is added to at least a part of an amorphous semiconductor layer mainly composed of Se, the charge multiplication It has been clarified that the action is maintained and high sensitivity can be easily obtained even for long-wavelength light. At this time, the concentration of the element added to the amorphous semiconductor layer containing Se as a main component does not have to be constant in the film thickness direction, and may have a concentration distribution. Figure 7 shows the sensitivity to long-wavelength light obtained under the same operating conditions.
It shows an example of the relationship of the average addition concentration of Te. As is clear from the figure, the sensitivity to long-wavelength light increases as the concentration of Te added increases, and it can be seen that the addition of Te is extremely effective. All you need is Te, Sb, Cd, B
At least one of i is added. The concentration of the substance to be added should be selected according to the use of the image pickup tube, but it is desirable that the average value is 0.01% by weight or more. However, if the amount of addition is too large, the electric field at the blocking contact portion becomes strong and the dark current increases, so that good characteristics cannot be obtained as an image pickup tube. Desirably, the average concentration of the added substance should be 50% by weight or less. Further, in order to obtain stable rectifying characteristics, for example, when the photoconductive film 3 shown in FIG. 1 is composed only of an amorphous semiconductor layer mainly composed of Se, the light incident side electrode interface portion thereof It is desirable not to add the above substances to the.

As a second means for solving the above-mentioned problems, rather than making the amorphous semiconductor layer itself have both the function of generating charges and the function of multiplying charges, a new generation of photocarriers different from that of the amorphous semiconductor layer is generated. There is a means of providing the layer in the photoconductive film adjacent to the amorphous semiconductor layer. In this photocarrier generation layer, most of the photocarriers are generated by absorbing incident light, and the photocarriers are guided to the amorphous semiconductor layer and multiplied in the amorphous semiconductor layer. Since the annihilation by free recombination of free electrons and free holes in the above is extremely small, it is possible to solve the above-mentioned problem of efficiency decrease due to photocarrier recombination inside the amorphous semiconductor layer. According to this means, by selecting the material of the photocarrier generation layer according to the purpose, it is possible to set the spectral sensitivity characteristic suitable for the use of the image pickup tube.

For example, amorphous Se can be easily formed into a uniform thin film on any photocarrier generation layer by the vacuum deposition method. Therefore, the one that has a photoconductive film using amorphous Se for the charge multiplication layer is an image pickup tube. Is extremely effective as a target part of

At this time, if the photocarrier generation layer is provided at a position closer to the transparent electrode than the amorphous Se charge multiplication layer, the charges that flow into the amorphous Se are mostly holes, so that the photogenerated electrons Since it is not necessary to consider the noise component due to running, it is more convenient for low noise amplification.

FIG. 8 is a principle configurational diagram showing a target portion in the case of implementing the image pickup tube according to the present invention. Light-transmissive substrate 81, light-transmissive electrode 82, photocarrier generation layer 86 that absorbs light to generate charges, amorphous semiconductor layer 84 serving as a charge multiplication layer, electron injection blocking layer 8
5 is shown. In the case where sufficient rectifying contact for preventing hole injection from the transparent electrode 82 to the photocarrier generating layer 86 cannot be obtained at the interface between the translucent electrode 82 and the photocarrier generating layer 86, It is also effective to intervene the rectifying contact auxiliary layer 83 to enhance the function of rectifying contact.

Needless to say, the material forming the photocarrier generation layer has a large light absorption coefficient and a high photoelectric conversion efficiency, but it is not necessarily an amorphous material and may be a crystalline material. Long. Specifically, for example, a chalcogenide-based amorphous semiconductor, a tetrahedral-based amorphous semiconductor, a III-V group compound semiconductor, a II-VI group compound semiconductor, or a compound thereof can be used. In this case, the inflow of holes from the transparent electrode to the photocarrier generation layer is blocked under a high electric field, but the inflow of holes from the photocarrier generation layer to the amorphous semiconductor layer must be easy. It is important not to be.

When the carriers do not travel smoothly from the photocarrier generation layer to the charge multiplication layer, the photocarrier generation layer and the charge multiplication layer are made of a compound material having a different composition from the photocarrier generation layer. It is also effective to insert an intermediate layer to improve the carrier running property. As this intermediate layer, for example, Se
Amorphous semiconductor layers mainly composed of bismuth, cadmium or their chalcogenides, tellurium, tin, and other substances that change the band gap, arsenic, germanium,
Negative space charges of antimony, indium, gallium or their chalcogenides, sulfur, chlorine, iodine, bromine, copper oxide, indium oxide, selenium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, gallium fluoride, indium fluoride, etc. It is effective to use a layer that changes the distribution of the electric field strength in the photoconductive film by adding a substance that forms the.

In any case, the purpose of the intermediate layer is to facilitate the inflow of electrons from the charge multiplication layer to the photocarrier generation layer and the inflow of holes from the photocarrier generation layer to the amorphous semiconductor layer under a high electric field. However, the material forming the intermediate layer is not necessarily limited to the above-mentioned elements and additives.

FIG. 9 is a principle configuration diagram of a target portion when the image pickup tube according to the present invention is implemented. Transparent substrate 91, transparent electrode
92, a photocarrier generation layer 96 that absorbs light to generate charges, an amorphous semiconductor layer 94 that functions as a charge multiplication layer, an electron injection blocking layer
95 is shown, and the transparent electrode 92 and the photocarrier generation layer 96 are shown.
If sufficient rectifying contact to prevent hole injection from the translucent electrode 92 to the photocarrier generating layer 96 cannot be obtained at the interface with the rectifying contact auxiliary layer 93, rectification is performed. The fact that strengthening the function of sexual contact is effective is the same as described in the explanation of FIG. In FIG. 9, the position of the intermediate layer 97 described above is shown in principle.

Regarding this intermediate layer, in order to change the electric field strength in the film, an amorphous semiconductor layer made of a tetrahedral material is used.
It was also effective to add a trace amount of substances that can modulate the conduction type such as group I and group V.

The inventors further studied the photocarrier generation layer and found that the following two are preferable.

First, a combination of at least one element from the first group consisting of Zn, Cd, Hg and Pb with at least one element from the second group consisting of O, S, Se and Te When a material is mainly used for the carrier generation layer, high photoelectric conversion efficiency can be obtained by this carrier generation layer. And
Since the optical bandgap width can be adjusted and the spectral sensitivity can be controlled by the combination of elements and the composition ratio, it is extremely excellent as a material for the above-mentioned photocarrier generation layer.

Examples of the material for the photocarrier generation layer include ZnS and Cd.
A material mainly containing at least one of S, ZnSe, CdSe, ZnTe, CdTe, HgCdTe, PbO and PbS is preferable.

Also, for example, CdSe, CdS, ZnCdTe, C in the photocarrier generation layer.
Targets using dTe and the like are suitable for imaging in the visible and near-infrared light regions, while targets using PbS, HgCdTe, etc. are suitable for infrared imaging. A target using PbO or the like for the photocarrier generation layer is suitable for X-ray images.

The photocarrier generation layer according to the present invention can be formed by vacuum vapor deposition while heating the base substrate, sputtering in the presence of an inert gas such as argon, or a reaction gas containing a component element. Further, after forming the photocarrier generation layer, heat treatment can be performed in a gas atmosphere of O ₂ , S, Se, Te or the like.

Furthermore, as a result of a study conducted by the present inventor, a layer of the photoconductive film that absorbs incident light and generates most of the photocarriers is mainly composed of an amorphous tetrahedral material, F, H, and Cl. By replacing it with an amorphous semiconductor containing at least one of them and combining it with a charge multiplication layer, an extremely high sensitivity is obtained which has solved the problem of efficiency decrease due to photocarrier recombination inside the amorphous semiconductor layer. It has been found that an image pickup tube having the above can be realized.

Most of the incident light is absorbed inside the photocarrier generation layer made of an amorphous tetrahedral material to generate electron-hole pairs. Amorphous tetrahedral materials containing halogen or hydrogen such as fluorine and chlorine have extremely low internal defects, so high photoelectric conversion efficiency can be obtained. In addition, film formation conditions, halogen or hydrogen content, and multiple tetrahedral materials can be used. Since the optical bandgap width can be adjusted by the mixed crystal of (1), the signal light can be efficiently absorbed with a thin film thickness. Among them, amorphous silicon containing hydrogen has a high absorptivity for light in the visible region, and unlike amorphous Se, almost all photons absorbed in the layer are separated into free electrons and free holes. Therefore, it is extremely excellent as a material for the above photocarrier generation layer.

In this case, the photocarrier generation layer is formed by reactive sputtering of a tetrahedral material in an atmosphere containing halogen or hydrogen such as fluorine or chlorine, or decomposition of a gas containing a hydride, fluoride, or chloride of the tetrahedral element. It can be formed by

For example, for amorphous silicon containing hydrogen, the deposition base substrate is kept at 100 to 300 ° C. and reactive sputtering of silicon is performed in a mixed atmosphere of an inert gas and hydrogen, or silicon such as monosilane or disilane is contained. The generated gas can be formed by a method of decomposing by applying energy such as plasma discharge, light, electromagnetic field or heat.

Further, sputtering of a mixture of silicon and germanium or a mixture of silicon and carbon, germanium containing germanium and methane containing carbon at the same time as monosilane,
By mixing and introducing acetylene etc. to decompose,
It is also possible to obtain an amorphous silicon germanium compound having an energy gap narrower than that of amorphous silicon or an amorphous silicon carbon compound having an energy gap wider than that of amorphous silicon, and it is possible to adjust the spectral sensitivity characteristic of the image pickup tube. .

At this time, between the amorphous silicon layer and the amorphous semiconductor layer,
The present invention exerts a further effect by facilitating the transfer of photocarriers from the amorphous silicon layer to the amorphous semiconductor layer through the interposition of the intermediate layer whose energy band structure or electrolytic strength is changed. This was the same as the case described above.

As the intermediate layer, a layer in which a specific substance is added to the above-described amorphous semiconductor layer mainly composed of Se, or a substance capable of modulating the conduction type such as group III or group V to an amorphous tetrahedral material, germanium It was also effective to use a layer that controls the band gap and space charge by mixing carbon, nitrogen, tin, etc., or a combination thereof.

The image pickup tube according to the present invention has been described above along with various aspects of the improved invention, but it goes without saying that the image pickup tube can be implemented by combining the above aspects, and further, such an image pickup tube is provided by the present invention. It goes without saying that the operation can be performed by the operation method of the image pickup tube.

Here, FIG. 10 shows a configuration example of a monochrome camera using the image pickup tube according to the present invention. As shown in the figure, the camera is an optical system 101 for forming an optical image, a coil assembly 102 including a deflection coil for an electron beam, a focusing coil and an image pickup tube, and a video signal current obtained from the coil assembly. It is composed of a circuit portion 103 for processing into a video signal, a circuit portion 104 including a deflection amplification circuit for generating a synchronizing signal and deflecting an electron beam, and a power supply portion 105.

In the case of a three-tube color camera, as is well known, the configuration shown in FIG. 10 is parallel to three systems corresponding to R, G, B and three colors, and a circuit portion for processing color signals is added to it. . The image pickup tube according to the present invention can be applied not only to a high-definition television image but also to a wide range of image new media by being applied to a camera having a basic configuration shown in FIG. 10, for example. It is a thing.

[Action]

The charge multiplication action in the amorphous semiconductor layer of the image pickup tube according to the present invention will be described with reference to FIG. FIG. 3 shows a translucent N-type electrode, an amorphous Se layer, and Sb ₂ S ₃ on a translucent glass substrate in this order.
It is the figure which showed the relationship between the output signal current and the target voltage in the target part of the pick-up tube which accumulated the layer. The figure shows the optical signal current and applied voltage when light is radiated from the transparent glass substrate side with voltage applied so that the transparent N-type electrode has a positive potential with respect to the Sb ₂ S ₃ layer. The target voltage is indicated by the electric field strength.

At the interface between the transparent N-type electrode and the amorphous Se layer, there is a rectifying action to prevent injection of holes, and in the Sb ₂ S ₃ layer, scanning electrons flow into the amorphous Se layer. Therefore, the present image pickup tube target operates as a so-called blocking type target. As is clear from the figure, the relationship between the signal current and the applied voltage consists of three regions A, B, and C.

An operation area C in FIG. 3 is an operation area of the image pickup tube according to the present invention. Prior to the description of the operation area C, other operation areas A and B will be described.

First, the operation of the area A in FIG. 3 will be described. For example, incident photons transmitted through the transparent substrate 21, the transparent electrode 22, and the rectifying contact auxiliary layer 23 shown in FIG. 2 are photoconductive films 24 made of an amorphous semiconductor layer.
To generate electron-hole pairs. When the target electric field is increased from zero, some of the generated electron-hole pairs are separated, the electrons are directed to the transparent electrode 22, and the holes are the electron injection blocking layer.
It reaches 25 and is read by the scanning electron beam. Therefore, the signal current increases as the target electric field becomes stronger. The above is the operation of the area A in FIG. In the operation of the region A, the number of electron-hole pairs generated in the photoconductive film 24 made of the amorphous semiconductor layer does not exceed the number of incident photons, and the photoconductive film 24 made of the amorphous semiconductor layer is not generated. The electric field is not strong enough and recombination of electrons and holes is actively performed, so that the gain of the target is 1 or less. Naturally, in this case, there is no amplification effect in the target.

Next, the operation of the area B in FIG. 3 will be described. The electric field in the target portion has a strength required to separate most of the electron-hole pairs generated by the incident photons and to drive them toward the transparent electrode 22 and the electron injection blocking layer 25 without recombining them. Then, the signal current starts to be saturated, and even if the electric field is further increased, a large increase in the signal current cannot be obtained. The above is the operation of the region B in FIG. In the operation of the region B, recombination is reduced as compared with the operation of the region A described above, but the number of electron-hole pairs generated in the photoconductive film 24 made of the amorphous semiconductor layer does not exceed the number of incident photons. Therefore, the gain of the target is 1 even at the maximum. That is, also in the case of the region B, there is no amplification effect on the target. The blocking target described in the above (Prior Art) section is operated in the range of the region B described here.

Next, a region C in FIG. 3 which is an operation region of the image pickup tube according to the present invention will be described. The inventors of the present invention described the above area B
When the target electric field is further increased from above, a charge multiplication action occurs in the photoconductive film 24 made of the amorphous semiconductor layer shown in FIG. 2, and the signal current sharply increases, and the gain becomes 1 or more. Found that you can get. The present invention is intended to increase the sensitivity of the photoconductive film used in the target portion of the image pickup tube, which utilizes the effect of charge multiplication that occurs in the region C described above.

The physical interpretation of the charge multiplication effect generated by the operating electric field in the region C of FIG. 3 has not been sufficiently clarified. However, in the relationship between the target electric field, the dark current and the afterimage of the present embodiment shown in FIG. 4, the region C of the present invention in which the gain is 1 or more as compared with the region B is shown.
No increase in afterimage is observed at all, and the dark current increase is small except in the electric field region where the gain is extremely high in the region C. Therefore, the charge multiplication effect in the image pickup tube according to the present invention is as described above. It is obvious that it is not the amplifying effect by the charge injection described in the section of the related art, which is a previously unknown amplifying effect that occurs when a strong electric field is applied to a blocking target using an amorphous semiconductor.

An electric field corresponding to the region C is applied to the image pickup tube target having the structure shown in FIG. 2 in the direction described in the section [Means for solving the problem]. When light is emitted from the glass substrate side of the image pickup tube target in this state, most of the incident light is
It is absorbed mainly on the transparent electrode side of the amorphous semiconductor layer to generate electron-hole pairs. Of these, electrons flow to the transparent electrode side, but holes travel in the amorphous semiconductor layer toward the electron injection blocking layer. Therefore, when the holes travel in the amorphous semiconductor layer under a high electric field to cause a charge multiplication effect, and the amorphous semiconductor layer is made thick enough to obtain desired characteristics, the charge multiplication effect is increased. As a result, high sensitivity with a gain of more than 1 can be obtained while maintaining the low afterimage property of the blocking target.

This charge multiplication effect when a high electric field is applied is already known as an avalanche amplification phenomenon in crystalline semiconductors, but microplasma is generated in crystalline semiconductors, and dark current is 10 ^-9 A / mm ² . If the element is large and the cross-sectional area of the element is large, the dark current cannot be suppressed to a low level. Therefore, there has been no practical application as a two-dimensional photoelectric conversion device such as an image pickup tube. On the other hand, it is generally considered that such a phenomenon does not occur in an amorphous semiconductor because there are many internal defects.
In fact, there has been no disclosure example of the amplification phenomenon in an amorphous semiconductor. However, as a result of detailed study by the present inventors, there is a charge multiplication effect in the amorphous semiconductor,
Moreover, even though it has a large area, the dark current is 100
It was found to be less than one-third.

Further, according to a detailed investigation by the inventors, it is found that the charge multiplication effect in the amorphous semiconductor is very remarkable for the holes, while it is slight for the electrons. all right. A normal photoconductive type image pickup tube is an operation type device in which holes travel in the photoconductive film. Therefore, if the above phenomenon in the amorphous semiconductor is used for the photoconductive type image pickup tube, it is possible to efficiently amplify the electric charges with low noise. Furthermore, an amorphous semiconductor is easy to form a thin film having a large area, and a target portion of the image pickup tube can be formed by a simple process. The operation method is extremely effective.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples. The image pickup tube according to the present invention is constructed as shown in FIG.

Example 1. A transparent electrode mainly composed of tin oxide is formed on a glass substrate, and amorphous Se is further added to the transparent electrode in an amount of 0.1-6.
Vacuum deposition is performed to a thickness of μm to obtain an amorphous semiconductor layer. 2x10 ^-1 Torr of Sb ₂ S ₃ as an electron injection blocking layer on amorphous Se
To obtain a target part of a photoconductive type image pickup tube with a blocking structure by vapor deposition to a thickness of 1000Å in an inert gas atmosphere.

Example 2 A transparent electrode mainly composed of indium oxide was formed on a glass substrate, and Se / As or Se / Ge having a thickness of 0.1 to 6 μm was formed on the transparent electrode. The crystalline semiconductor layer is formed by a vacuum evaporation method. When forming a film, Se
And As ₂ Se ₃ or Se and Ge are simultaneously evaporated from different boats and deposited on the substrate so that the concentration of As or Ge becomes 2% by weight on average. Then, Sb ₂ S ₃ as an electron injection blocking layer is vapor-deposited in an inert gas atmosphere of 1 × 10 ^-1 Torr to a thickness of 800 Å to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

Example 3. A transparent electrode mainly composed of indium oxide was formed on a glass substrate, and a 0.5-nm thick film of Se, As, and Ge was formed on the transparent electrode.
An amorphous semiconductor layer having a thickness of ˜6 μm is formed. In forming the film, Se, As ₂ Se ₃ , and GeSe are simultaneously evaporated from different boats and deposited on the substrate so that the total amount of As and Ge becomes 3% by weight on average. On top of that, Sb ₂ S ₃ was deposited as an electron injection blocking layer in an inert gas atmosphere of 2 × 10 ^-1 Torr at 800 Å
To obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

The target portion of the image pickup tube obtained in each of Examples 1, 2 and 3 is incorporated into an image pickup tube housing containing an electron gun to obtain a photoconductive type image pickup tube. When the obtained image pickup tube is operated with a target electric field of 8 × 10 ⁷ V / m or more, signal amplification occurs in the amorphous semiconductor layer. For example, when 1.2 × 10 ⁸ V / m, an output with a gain of about 10 is obtained. To be

Further, in Examples 1, 2 and 3, it is also possible to interpose a vacuum deposition film of cerium oxide having a film thickness of 300Å, for example, as a rectifying contact auxiliary layer between the transparent electrode and the amorphous semiconductor layer. . In this case, since the hole injection blocking function from the translucent electrode is improved, it is possible to operate in a higher electric field and obtain a sensitivity of 10 or more in charge multiplication factor.

Example 4 A transparent electrode composed mainly of tin oxide is formed on a glass substrate, and an amorphous film is formed on the transparent electrode by an evaporation method.
The Se layer is formed to a thickness of 1 to 3 μm to form an amorphous semiconductor layer. Sb ₂ S ₃ was used as an electron injection blocking layer on this with 2 × 10 ^-1 Tor
Evaporation is performed to a thickness of 0.1 μm in an inert gas atmosphere of r to obtain a target portion of a photoconductive image pickup tube having a blocking structure.

Example 5 A transparent electrode mainly composed of indium oxide was formed on a glass substrate, and CeO ₂ was further added on the transparent electrode by 0.03 μm.
Evaporate to a thickness of m. An amorphous Se layer having a thickness of 0.5 to 2 μm is formed thereon by a vacuum vapor deposition method to form an amorphous semiconductor layer. On top of that, Sb ₂ S ₃ is added as 1 × 10 ^-1 T as an electron injection blocking layer.
Evaporation is performed to a thickness of 0.1 μm in an inert gas atmosphere of orr to obtain a target portion of a photoconductive image pickup tube having a blocking structure.

Example 6 A transparent electrode mainly containing tin oxide is formed on a glass substrate. GeO ₂ 0.015μm, C on top of this transparent electrode
eO ₂ is evaporated to a thickness of 0.015 μm. An amorphous Se layer having a thickness of 0.02 to 0.06 μm is also formed thereon by a vacuum evaporation method.
Next, Se and LiF are evaporated from separate boats and 0.02
Form an amorphous layer with a thickness of ˜0.06 μm. At this time, LiF
Concentration is 4000 ppm by weight, and is uniformly distributed in the film thickness direction. An amorphous Se layer is formed thereon by a vacuum vapor deposition method so that the total film thickness is 1 to 8 μm. Sb ₂ S ₃ was deposited as an electron injection blocking layer on the amorphous Se layer to a thickness of 0.1 μm in an inert gas atmosphere of 2 × 10 ^-1 Torr to form a blocking type photoconductive image pickup tube. Get the target part.

Example 7 A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and CeO ₂ is vapor-deposited thereon to a thickness of 0.03 μm. On top of that, a film thickness of Se, As and LiF of 0.02 to 0.04
A μm amorphous semiconductor layer is formed by a vacuum evaporation method. When forming a film, Se, As ₂ Se ₃ and LiF are simultaneously evaporated from different boats and evaporated, and the As concentration is 3 to
6% by weight, and the concentration of LiF should be 3000 to 6000 ppm by weight on average. On top of that, the film thickness of Se, As and LiF is 0.03 to 0.04.
A 5 μm amorphous semiconductor layer is formed by a vacuum evaporation method.
At this time, the As concentration is 2 to 5% by weight, and the LiF concentration is 15,000 on average.
Weight ppm An amorphous semiconductor layer made of Se and As is formed thereon by a vacuum vapor deposition method to have a total film thickness of 1 to 4 μm. At this time, the As concentration is 1 to 3% by weight. Sb ₂ S ₃ as an electron injection blocking layer is vapor-deposited thereon in an inert gas atmosphere of 1 × 10 ^-1 Torr to a thickness of 0.1 μm to obtain a target portion of a photoconductive type image pickup tube having a blocking type structure.

Example 8. A light-transmissive electrode mainly composed of indium oxide is formed on a glass substrate, and a transparent electrode having a film thickness of 0.02 to about 2 consisting of Se and LiF is formed thereon.
An amorphous semiconductor layer having a thickness of 0.03 μm is formed by a vacuum evaporation method. When forming a film, Se and LiF are simultaneously vaporized from separate boats, and the average LiF concentration is 200.
Make it 0 ppm by weight. An amorphous semiconductor layer made of Se and LiF and having a film thickness of 0.03 to 0.04 μm is formed thereon by a vacuum deposition method. The concentration of LiF at this time is 8,000 to 15,000 on average.
ppm. Further, Se and Te are evaporated from separate boats to form an amorphous semiconductor layer having a film thickness of 0.02 to 0.04 μm. At this time, the Te concentration is 5 to 15% by weight. Next, such an amorphous Se layer is formed by the vacuum evaporation method, and the total film thickness is 1
The thickness should be about 4 μm. Further, Sb ₂ S ₃ as an electron injection blocking layer is vapor-deposited to a thickness of 0.08 μm in an inert gas atmosphere of 2 × 10 ^-1 Torr to obtain a target portion of a photoconductive type image pickup tube having a blocking type structure. .

The target portion of the image pickup tube obtained in each of Examples 4, 5, 6, 7 and 8 is incorporated into an image pickup tube casing containing an electron gun to obtain a photoconductive type image pickup tube. When the obtained image pickup tube is operated at an electric field of 7 × 10 ⁷ V / m or more, signal amplification occurs in the amorphous photoconductive layer,
For example, 1.2 × 10 ⁸ V / m for a target with a film thickness of 2 μm
At that time, an output with a gain of 10 or more was obtained.

Example 9 A transparent electrode composed mainly of tin oxide was formed on a glass substrate, and Se and Te were vacuum-deposited on the transparent electrode from separate boats to a thickness of 1 to 2 μm. To do. At this time, the Te concentration is set to 0.01% by weight and is uniformly distributed in the film thickness direction. Sb ₂ S ₃ as an electron injection blocking layer was vapor-deposited in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 0.1 μm on the amorphous semiconductor layer mainly composed of Se to form a blocking structure. Obtain the target portion of the photoconductive image pickup tube.

Example 10. A translucent electrode mainly containing tin oxide is formed on a glass substrate. Se and Te are vacuum-deposited on the translucent electrode from separate boats to a thickness of 1 to 3 μm. At this time Te
The concentration is 0% by weight at the start of vapor deposition, and is gradually increased as the vapor deposition progresses.
Make sure to use the weight percent. On this photoconductive layer, Sb ₂ S ₃ was deposited as an electron injection blocking layer in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 0.1 μm, and the target of the photoconductive type image pickup tube with the blocking type structure was deposited. Get the part.

Example 11. A translucent electrode mainly composed of indium oxide is formed on a glass substrate. Se and As or Se on top of this transparent electrode
And a layer of 0.01 to 1 μm in thickness made of Ge are formed by a vacuum evaporation method. For film formation, Se and As ₂ S ₃ or Se
And Ge are simultaneously vaporized from different boats so that the concentration of As or Ge becomes 3 wt% on average. Next, a layer of Se and Te or Sb, and As or Ge having a film thickness of 0.01 to 0.06 μm is formed by a vacuum evaporation method.
For the film formation, Se, Te or Sb, and As ₂ Se ₃ or Ge are evaporated from different boards at the same time and vapor-deposited, and the concentration of Te or Sb is 10 to 15 wt% on average, As or Ge.
The average concentration of 2% by weight. Furthermore Se and A
A layer made of s or Se and Ge is formed by a vacuum vapor deposition method to have a total film thickness of 2 to 3 μm. When forming a film,
Se and As ₂ Se ₃ , or Se and Ge are simultaneously evaporated from different boats and vapor-deposited so that the concentration of As or Ge becomes 2% by weight on average. On top of that, as an electron injection blocking layer
Sb ₂ S ₃ 0.08 μm in an inert gas atmosphere of 1 × 10 ^-1 Torr
To obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

Example 12. A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and a film thickness of 0.5 to 1 composed of Se, As, and Ge is formed on the transparent electrode.
Form a μm layer. For the film formation, Se and As ₂ S
e ₃ and Ge are evaporated and vaporized simultaneously from different boats so that the total concentration of As and Ge becomes 3 wt% on average. This is the first layer. Next, a layer having a film thickness of 0.01 to 0.06 μm, which is made of Se, As and at least one of Te, Sb, Cd and Bi, is formed as a second layer on the first layer by a vacuum evaporation method.
In forming the film, at least one of Se, As ₂ Se ₃ and Te, Sb, Cd, Bi is vaporized simultaneously by vaporization from separate boats. The concentrations of Te, Sb, Cd and Bi in the second layer are changed in the film thickness direction. The concentration of the second layer at the start of vapor deposition is set to 0% by weight, and the concentration is gradually increased as the vapor deposition progresses so that the concentration at the intermediate point of the vapor deposition of the second layer becomes a maximum value. After that, the concentration is gradually decreased so that the concentration becomes 0 wt% again at the end of the vapor deposition of the second layer. Second time at this time
The average As concentration in the layer is 2% by weight, and the total concentration of one or more of Te, Sb, Cd and Bi is 15 to 45% by weight in the second layer. This completes the vapor deposition of the second layer. A layer made of Se and As or Se and Ge is formed as a third layer on the second layer by a vacuum vapor deposition method to have a total film thickness of 2 to 3 μm.
In forming the film, Se and As ₂ Se ₃ or Ge are simultaneously evaporated from different boats to be vapor-deposited so that the concentration of As or Ge becomes 2% by weight on average. Further, Sb ₂ S ₃ as an electron injection blocking layer is vapor-deposited to a thickness of 0.08 μm in an inert gas atmosphere of 2 × 10 ^-1 Torr to obtain a target portion of a photoconductive type image pickup tube having a blocking type structure. .

The target portion of the image pickup tube obtained in each of Examples 9, 10, 11 and 12 is incorporated into an image pickup tube casing having an electron gun built therein to obtain a photoconductive type image pickup tube. When the obtained image pickup tube is operated in a target electric field of 8 × 10 ⁷ V / m or more, signal amplification occurs in the amorphous semiconductor layer. For example, when 1.2 × 10 ⁸ V / m, an output with a quantum efficiency of 10 or more is obtained. To be

In Examples 9, 10, 11 and 12 described above, the film thickness of the rectifying contact auxiliary layer between the transparent electrode and the amorphous semiconductor layer is, for example,
It is also possible to interpose a vacuum deposited film of 0.03 μm cerium oxide. In this case, the function of preventing hole injection from the translucent electrode is improved, so that operation in a higher electric field can be performed and higher sensitivity can be realized.

Example 13 A transparent electrode composed mainly of tin oxide was formed on a glass substrate, and Se and LiF were evaporated from separate boats on the transparent electrode to a thickness of 1 to 6 μm. Vacuum deposition. At this time, the concentration of LiF is set to 500 ppm by weight and is uniformly distributed in the film thickness direction. Sb ₂ S _{3 is formed} on top of this as an electron injection blocking layer.
Is vapor-deposited in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 0.1 μm to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

Example 14 A transparent electrode mainly composed of indium oxide was formed on a glass substrate, and a layer of Se and CaF _{2 having a} thickness of 0.01 to 0.045 μm was formed on the transparent electrode by a vacuum deposition method. Formed by. When forming a film, Se and CaF ₂ are simultaneously evaporated from different boats and vapor-deposited on a substrate so that the concentration of CaF ₂ is 3000 ppm by weight on average. Se is vapor-deposited thereon to make the total film thickness 1 to 6 μm. Sb ₂ S ₃ as an electron injection blocking layer is vapor-deposited thereon in an inert gas atmosphere of 1 × 10 ^-1 Torr to a thickness of 0.1 μm to obtain a target portion of a photoconductive type image pickup tube having a blocking type structure.

Example 15. A transparent electrode mainly containing tin oxide is formed on a glass substrate. Se is vapor-deposited on the transparent electrode to a thickness of 0.02 to 0.06 μm. Next, Se and KF are evaporated from separate boats and vacuum-deposited to a thickness of 0.02 to 0.06 μm. At this time, the concentration of KF is set to 500 ppm by weight and is uniformly distributed in the film thickness direction. A Se layer is formed thereon by a vacuum vapor deposition method to have a total film thickness of 1 to 3 μm. Sb ₂ S ₃ as an electron injection blocking layer on the Se layer was 0.1 μm in an inert gas atmosphere of 2 × 10 ^-1 Torr.
To obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

Example 16. A transparent electrode mainly composed of indium oxide was formed on a glass substrate, and a layer of Se, As and LiF having a film thickness of 0.01 to 0.045 μm was vacuum-deposited on the transparent electrode. It is formed by the method. When forming a film, Se, As ₂ Se ₃ and LiF are simultaneously evaporated from different boats to be deposited, and the As concentration is 3 to 6 wt% and the LiF concentration is 2000 to 6000 wt p on average.
Try to be pm. On top of that, the film thickness consisting of Se, As and LiF
A layer of 0.03 to 0.045 μm is formed by a vacuum evaporation method. At this time, the As concentration is 2 to 3.5% by weight, and the LiF concentration is 10000 on average.
Weight ppm Se and As are vapor-deposited thereon in vacuum to make the total film thickness 1 to 4 μm. At this time, the As concentration is 1 to 3% by weight. Sb ₂ S ₃ is deposited on top of this as an electron injection blocking layer.
By vapor deposition to a thickness of 0.1 μm in an inert gas atmosphere of × 10 ^-1 Torr, a target portion of a photoconductive image pickup tube having a blocking structure is obtained.

Example 17. A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and a film thickness of 0.01 to 0.0 composed of Se and LiF is formed on the transparent electrode.
A 15 μm layer is formed by the vacuum evaporation method. In forming a film, Se and LiF are simultaneously evaporated from separate boats to be vapor-deposited so that the LiF concentration becomes 3000 ppm by weight on average. On top of that, a film thickness of Se and LiF 0.03 to 0.045μ
The layer of m is formed by a vacuum evaporation method. The LiF concentration at this time is 8000 to 15000 ppm by weight on average. Further, Se and Te are evaporated from separate boats to form a layer having a film thickness of 0.02 to 0.05 μm. At this time, the Te concentration is 5 to 15% by weight.
Next, Se is vapor-deposited so that the total film thickness becomes 1 to 4 μm. On top of that, Sb ₂ S _{3 is formed} as an electron injection blocking layer.
Is vapor-deposited in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 0.08 μm to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

The image pickup tube target portion obtained in each of Examples 13, 14, 15, 16 and 17 is incorporated into an image pickup tube casing having an electron gun built therein to obtain a photoconductive type image pickup tube. When the obtained image pickup tube is operated in an electric field of 8 × 10 ⁷ V / m or more, signal amplification occurs in the amorphous photoconductor layer,
For example, an output with a quantum efficiency of 10 or higher was obtained at 1.2 × 10 ⁸ V / m.

In Examples 13, 14, 15, 16 and 17, the film thickness of the rectifying contact auxiliary layer between the transparent electrode and the amorphous semiconductor layer is, for example,
It is also possible to interpose a vacuum deposited film of 0.03 μm cerium oxide. In this case, the function of preventing hole injection from the transparent electrode is further improved, so that operation in a higher electric field can be performed and higher sensitivity can be realized.

Example 18. A transparent electrode containing tin oxide as a main component is formed on a glass substrate. An amorphous Se semiconductor layer is formed on this translucent electrode by a vacuum evaporation method.

Further, Se and SeO ₂ are evaporated from separate boats on this and vacuum deposited to a thickness of 0.02 to 0.06 μm. At this time,
The SeO ₂ concentration is 2500 ppm, and the SeO ₂ is uniformly distributed in the film thickness direction.
Se is vapor-deposited thereon to a thickness of 0.05 to 0.06 μm, and the thickness of the entire amorphous semiconductor layer mainly composed of Se is set to 1 to 6 μm. Sb ₂ S ₃ was used as an electron injection blocking layer on this with 2 × 10 ^-1 Tor
Evaporation is performed to a thickness of 0.1 μm in an inert gas atmosphere of r to obtain a target portion of a photoconductive image pickup tube having a blocking structure.

Example 19. A transparent electrode containing tin oxide as a main component is formed on a glass substrate. An amorphous Se semiconductor layer is formed on this translucent electrode by a vacuum evaporation method. On top of that, As ₂ Se ₃ and GaF ₃ are evaporated from separate boats and vacuum deposited to a thickness of 0.03 to 0.06 μm. At this time, the concentration of GaF ₃ is set to 2000 ppm and is uniformly distributed in the film thickness direction. The thickness of the entire amorphous semiconductor layer mainly composed of Se is set to 1 to 6 μm. Sb ₂ S ₃ as an electron injection blocking layer is vapor-deposited thereon in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 0.1 μm to obtain a target portion of a photoconductive type imaging tube having a blocking structure.

Example 20. A translucent electrode mainly composed of indium oxide is formed on a glass substrate. A layer of Se and CaF _{2 having} a film thickness of 0.01 to 0.05 μm is formed on the translucent electrode by a vacuum vapor deposition method.
When forming a film, Se and CaF ₂ were vaporized by simultaneous vaporization from separate boats, and the CaF ₂ concentration was 6000 pp on average.
Make it m. Amorphous Se layer is formed on it by vacuum evaporation method, then As ₂ Se ₃ is evaporated from the boat to 0.03 ~
Vacuum-deposit to a thickness of 0.06 μm. On top of that, Se and Ca
Evaporating F ₂ from separate boats 0.02 to 0.06 μm
Vacuum deposition to the thickness of. At this time, the concentration of GaF ₃ is 4000ppm
And distribute uniformly in the film thickness direction. The thickness of the entire amorphous semiconductor layer mainly composed of Se is set to 1 to 6 μm. Then, Sb ₂ S ₃ as an electron injection blocking layer is vapor-deposited in an inert gas atmosphere of 1 × 10 ^-1 Torr to a thickness of 0.08 μm to obtain a target portion of a photoconductive type image pickup tube having a blocking type structure.

Example 21. A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and a layer of Se, As and LiF having a film thickness of 0.01 to 0.06 μm is vacuum-deposited on the transparent electrode. It is formed by the method. When forming a film, Se, As ₂ Se ₃ and LiF are simultaneously vaporized from separate boats so that the As concentration is 3 to 6 wt% and the LiF concentration is 3000 to 6000 ppm on average. To do. On top of that, the film thickness of Se, As and LiF 0.03〜
A 0.05 μm layer is formed by the vacuum evaporation method. At this time
The concentration is 2 to 3.5% by weight, and the LiF concentration is 15000 ppm on average. Then, Se and As ₂ Se ₃ are simultaneously evaporated from different boats to form an amorphous semiconductor layer having an As concentration of 1 to 3% by weight. On top of that, As ₂ Se ₃ and In ₂ O ₃ are evaporated from separate boats and vacuum-deposited to a thickness of 0.01 to 0.1 μm. At this time, the concentration of In ₂ O ₃ is set to 700 ppm and is distributed uniformly in the film thickness direction. Then, Se and As ₂ Se ₃ are simultaneously evaporated from different boats and evaporated to a thickness of 0.01 to 0.06 μm. At this time, the As concentration is 1 to 3% by weight. The thickness of the entire amorphous semiconductor layer mainly composed of Se is set to 1 to 6 μm. Sb ₂ S ₃ was added as an electron injection blocking layer on top of it at 1 × 10 ^-1 Torr.
By vapor-depositing to a thickness of 0.08 μm in an atmosphere of an inert gas of r, a target portion of a photoconductive type image pickup tube having a blocking structure is obtained.

Example 22. A light-transmissive electrode mainly composed of indium oxide is formed on a glass substrate, and a film thickness of Se and LiF of 0.03 to 0.0 is formed thereon.
A 6 μm layer is formed by vacuum evaporation. When forming a film, Se and LiF are simultaneously evaporated from separate boats to be vapor-deposited so that the LiF concentration becomes 4000 ppm on average. A layer of Se and LiF having a thickness of 0.03 to 0.05 μm is formed thereon by a vacuum evaporation method. At this time, the concentration of LiF is 8000 to 10000 ppm on average. Further, Se and Te are evaporated from separate boats to form a layer having a film thickness of 0.02 to 0.06 μm. At this time, the Te concentration is 5 to 15% by weight. An amorphous Se layer is formed on it by a vacuum evaporation method. On top of that As ₂ S
e ₃ and In ₂ O ₃ are evaporated from separate boats, respectively
Vacuum deposit to a thickness of 0.09 μm. At this time, the concentration of In ₂ O ₃ is set to 500 ppm and is distributed uniformly in the film thickness direction. Then Se and In
Evaporating ₂ O ₃ from separate boats 0.02 to 0.2 μm
Vacuum-deposit to thickness. At this time, the concentration of In ₂ O ₃ is set to 1000 ppm and is uniformly distributed in the film thickness direction. The thickness of the entire amorphous semiconductor layer mainly composed of Se is set to 1 to 6 μm. Further, Sb ₂ S ₃ as an electron injection blocking layer is vapor-deposited to a thickness of 0.1 μm in an inert gas atmosphere of 2 × 10 ^-1 Torr to obtain a target portion of a blocking type photoconductive image pickup tube. .

The image pickup tube target portion obtained in each of Examples 18, 19, 20, 21, and 22 is incorporated into an image pickup tube casing containing an electron gun to obtain a photoconductive type image pickup tube. When the obtained image pickup tube is operated in an electric field of 8 × 10 ⁷ V / m or more, signal amplification occurs in the amorphous semiconductor layer. For example, at 1.2 × 10 ⁸ V / m, an output with a quantum efficiency of 10 or more is obtained. Was given.

Further, in Examples 18, 19, 20, 21, and 22 above, a rectified contact auxiliary layer, for example, a cerium oxide vacuum-deposited film having a thickness of 0.03 μm was interposed between the transparent electrode and the amorphous semiconductor layer. You can also stain. In this case, the function of blocking the injection of holes from the translucent electrode is further improved, so that it is possible to operate in a higher electric field and further increase the charge multiplication factor.

Example 23. A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and a chalcogenide amorphous semiconductor or tetrahedral system having a film thickness of 0.01 to 1 μm is formed as a photocarrier generation layer on the transparent electrode. Amorphous semiconductor or III-V
A group compound semiconductor or a II-VI group compound semiconductor layer is formed. Further, amorphous Se is vacuum-deposited thereon to a thickness of 0.5 to 6 μm. As an electron injection blocking layer on the amorphous Se layer
Sb ₂ S ₃ is vapor-deposited in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 1000Å to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

Example 24. On a glass substrate, a transparent electrode mainly composed of indium oxide was formed, and the same photocarrier generation layer as in Example 23 was further provided thereon, and amorphous Se and As were further provided thereon. Or Se
And an amorphous semiconductor layer made of Ge and having a thickness of 0.5 to 6 μm is vacuum-deposited. Sb ₂ S ₃ 2x1 as an electron injection blocking layer
Evaporation is performed to a thickness of 1000Å in an inert gas atmosphere of 0 ^-1 Torr to obtain a target portion of a photoconductive type image pickup tube having a blocking type structure.

The target portion of the image pickup tube obtained in each of Examples 23 and 24 is incorporated into an image pickup tube casing containing an electron gun to obtain a photoconductive type image pickup tube. When the obtained image pickup tube is operated in an electric field of 8 × 10 ⁷ to 2 × 10 ⁸ V / m, signal amplification occurs in the amorphous photoconductor layer. For example, when 1.2 × 10 ⁸ V / m The output was 10 times that when all the light was converted into the signal current.

In Examples 23 and 24, a rectifying contact auxiliary layer having a film thickness of 300 Å is provided between the transparent electrode and the amorphous semiconductor layer.
It is also possible to interpose a vacuum deposited film of cerium oxide, etc. In this case, the function of preventing hole injection from the translucent electrode is improved, so that operation in a higher electric field can be performed and sensitivity with a charge multiplication factor of 10 or more can be obtained.

Example 25. A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and a thin layer of amorphous silicon nitride containing hydrogen is further deposited thereon as a hole injection blocking layer by 100 to 1000Å. To do. Next, while keeping the substrate at 200 to 300 ° C., monosilane is decomposed by glow discharge to deposit 0.5 to 3 μm of amorphous silicon containing hydrogen. Further thereon, as an intermediate layer, Se containing 20% of arsenic is vapor-deposited in an amount of 300 liters, and then Se containing 2% of arsenic is vacuum-deposited to a thickness of 0.5 to 6 μm. Sb ₂ S ₃ as an electron injection blocking layer on the amorphous Se layer
Is vapor-deposited to a thickness of 1000Å in an inert gas atmosphere of 2 × 10 ^-1 Torr to obtain a target portion of a photoconductive type image pickup tube having a blocking type structure.

Example 26. A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and a thin layer of amorphous silicon nitride containing hydrogen is deposited thereon as a hole injection blocking layer by 100 to 1000Å. .
Next, while holding the substrate at 200 to 300 ° C., a mixed gas of monosilane and diborane was decomposed by glow discharge to give 0.5 to 3 μm of amorphous silicon containing 5 ppm of boron.
accumulate. Subsequently, as an intermediate layer, 200 Å of amorphous Se containing 30% tellurium and 500 Å of amorphous Se having a composition distribution in which the arsenic concentration gradually decreases from 20% to 2% are stacked, and further 2% of arsenic is further contained. Vacuum deposit Se to a thickness of 0.5 to 6 μm. Sb as an electron injection blocking layer on the amorphous Se layer
₂ S ₃ is vapor-deposited in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 1000 Å to obtain a target portion of a photoconductive image pickup tube having a blocking structure.

The target portion of the image pickup tube obtained in each of Examples 25 and 26 is incorporated into an image pickup tube casing containing an electron gun to obtain a photoconductive type image pickup tube. When the obtained image pickup tube is operated by applying a voltage so that the electric field strength applied to the charge multiplication layer becomes 8 × 10 ⁷ to 2 × 10 ⁸ V / m, signal amplification occurs in the amorphous semiconductor layer. , For example, when the electric field strength applied to the charge multiplication layer is 1.2 × 10 ⁸ V / m,
High sensitivity with a gain of about 10 was obtained.

Example 27. A translucent electrode mainly composed of indium oxide is formed on a translucent substrate, and CdSe as a photocarrier generation layer is formed on the translucent electrode in a thickness of 0.01 to 1 μm. Vacuum deposition. After heat-treating this glass face plate at a temperature of 200 to 400 ° C. in an oxygen atmosphere, 0.5 to 0.5 of amorphous Se is further deposited thereon.
Vacuum deposit to a thickness of 6 μm. Sb ₂ S ₃ was deposited on the amorphous Se layer as an electron injection blocking layer in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 1000Å, and was used as the target of a photoconductive image pickup tube with a blocking structure. Get the part.

Example 28. A light-transmitting electrode mainly containing indium oxide is formed on a light-transmitting substrate, the same photocarrier generation layer as in Example 27 is further formed on the light-transmitting electrode, and amorphous Se is further formed thereon. As or Se
And an amorphous semiconductor layer made of Ge and having a thickness of 0.5 to 6 μm is vacuum-deposited. Sb ₂ S ₃ 2x1 as an electron injection blocking layer
Evaporation is performed to a thickness of 1000Å in an inert gas atmosphere of 0 ^-1 Torr to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

Example 29. A translucent electrode mainly composed of indium oxide is formed on a translucent substrate, and ZnSe film having a thickness of 0.01 to 0.1 μm is further formed as a photocarrier generation layer on the translucent electrode. The compound is vacuum deposited to a thickness of 0.1-1 μm. After heat-treating this glass face plate in an oxygen atmosphere at a temperature of 200 to 600 ° C., amorphous Se is vacuum-deposited thereon to a thickness of 0.5 to 6 μm. Sb as an electron injection blocking layer on the amorphous Se layer
₂ S ₃ is vapor-deposited in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 1000 Å to obtain a target portion of a photoconductive image pickup tube having a blocking structure.

Example 30. A translucent electrode mainly composed of indium oxide was formed on a signal light transmissive substrate, and a layer made of PbS and PbO was formed on the translucent electrode to a thickness of 0.01 to 1 μm. Vacuum deposition. Further, amorphous Se is vacuum-deposited thereon to a thickness of 0.5 to 6 μm. Sb ₂ S ₃ was deposited on the amorphous Se layer as an electron injection blocking layer in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 1000Å, and was used as the target of a photoconductive image pickup tube with a blocking structure. Get the part.

Example 31. A light-transmissive electrode made of a light-transmissive metal thin film was formed on a signal light-transmissive substrate, and a HgCdTe compound as a photocarrier generation layer was formed on the light-transmissive electrode in a thickness of 0.01 to 0.1 μm. accumulate. Further, amorphous Se is vacuum-deposited thereon to a thickness of 0.5 to 6 μm. Sb as an electron injection blocking layer on the amorphous Se layer
₂ S ₃ is vapor-deposited in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 1000 Å to obtain a target portion of a photoconductive image pickup tube having a blocking structure.

The image pickup tube target portion obtained in each of Examples 27, 28, 29, 30, and 31 is incorporated into an image pickup tube casing containing an electron gun to obtain a photoconductive type image pickup tube. The obtained image pickup tube was operated by applying a voltage so that the electric field applied to the charge multiplication layer was 8 × 10 ⁷ to 2 × 10 ⁸ V / m. Signal amplification occurs at, for example, the electric field applied to the charge multiplication layer
At 1.2 × 10 ⁸ V / m, the output was 10 times that when all incident light was converted to signal current.

Example 32 A glass substrate provided with a light-transmissive electrode mainly composed of indium oxide on the surface was placed in a sputtering apparatus, and a SiO ₂ thin layer as a hole injection blocking layer was formed on the light-transmissive electrode in a thickness of 100-. 100
0Å Accumulate. Next, while the substrate was kept at 200 to 300 ° C., a mixed gas of hydrogen and argon was introduced, high frequency power was applied to the polycrystalline silicon placed on the electrode, and the amorphous silicon containing hydrogen was 0.5 to 0.5 on the substrate. Deposit 3 μm. Further, amorphous Se is vacuum-deposited thereon to a thickness of 0.5 to 6 μm.
2 × 10 Sb ₂ S ₃ was used as an electron injection blocking layer on the amorphous Se layer.
-Evaporate to a thickness of 1000Å in an inert gas atmosphere of ^-1 Torr,
A target portion of a photoconductive image pickup tube having a blocking structure is obtained.

Example 33. A light-transmissive electrode mainly containing indium oxide was formed on a glass substrate, and a photocarrier generation layer made of the same amorphous silicon as in Example 32 was provided thereon, and an amorphous film was further formed thereon. quality
An amorphous semiconductor layer made of Se and As or Se and Ge and having a film thickness of 0.5 to 6 μm is vacuum-deposited. Sb ₂ S ₃ was deposited on top of it as an electron injection blocking layer in an inert gas atmosphere of 2 × 10 ^-1 Torr.
Evaporate to a thickness of Å to obtain the target part of the photoconductive image pickup tube with the blocking structure.

The target portion of the image pickup tube obtained in each of Examples 32 and 33 is incorporated into an image pickup tube casing containing an electron gun to obtain a photoconductive type image pickup tube. When the obtained image pickup tube is operated by applying a voltage so that the electric field strength applied to the charge multiplication layer becomes 8 × 10 ⁷ to 2 × 10 ⁸ V / m, signal amplification in the amorphous semiconductor layer occurs. Occurs, for example, when the electric field strength applied to the charge multiplication layer is 1.2 × 10 ⁸ V / m,
High sensitivity with a gain of about 10 was obtained.

Example 34. A transparent electrode mainly composed of tin oxide was formed on a glass substrate, and GeO ₂ was added as 200 Å as a rectifying contact auxiliary layer and CeO.
Evaporate ₂ to a thickness of 200Å in a vacuum of 3 × 10 ^-6 Torr. Se and As ₂ Se ₃ as an amorphous semiconductor layer are vapor-deposited thereon from separate vapor deposition boats to a thickness of 1 μm. In this case, the As concentration is 2% by weight, and is distributed uniformly in the film thickness direction. The amorphous semiconductor layer is deposited in a vacuum of 2 × 10 ^-6 Torr. 3 × 10 ₃ of Sb ₂ S ₃ was formed as an electron injection blocking layer on the amorphous semiconductor layer.
-Deposit to a thickness of 800Å in an argon atmosphere of ^-1 Torr.
An image pickup tube incorporating the target portion formed as described above is formed, and the amorphous semiconductor layer is operated in an electric field of 8 × 10 ⁷ V / m to 2 × 10 ⁸ V / m which causes a charge multiplication effect.

Example 35. A transparent electrode mainly containing indium oxide is formed on a glass substrate. CeO ₂ is vapor-deposited as a rectifying contact auxiliary layer on the transparent electrode to a thickness of 300 Å in a vacuum of 3 × 10 ^-6 Torr. Se is deposited thereon as an amorphous semiconductor layer to a thickness of 2 μm in a vacuum of 2 × 10 ⁻⁶ Torr. On this amorphous semiconductor layer, Sb ₂ S ₃ is deposited as an electron injection blocking layer to a thickness of 1000Å in an argon atmosphere of 2 × 10 ^-1 Torr. An image pickup tube incorporating the target portion formed as described above is formed, and its amorphous semiconductor layer is subjected to a charge multiplication effect of 8 × 10.
Operate in an electric field of ⁷ V / m to 2 × 10 ⁸ V / m.

Example 36. A light-transmitting electrode mainly composed of indium oxide was formed on a glass substrate, and further GeO ₂ was used as a rectifying contact auxiliary layer.
Å, CeO ₂ is evaporated to a thickness of 200Å. This vapor deposition is 2 × 10
-Perform in a vacuum of ^-6 Torr. Subsequently, an amorphous semiconductor layer is deposited. For the amorphous semiconductor layer, Se and As ₂ Se ₃ are first vapor-deposited from separate vapor deposition boats to a thickness of 300 Å. In this case, the As concentration is 3% by weight, and is distributed uniformly in the film thickness direction. Then Se, A
s ₂ Se ₃ and LiF are vapor-deposited to the thickness of 600 Å by separate vapor deposition boats. At this time, the As concentration is 2% by weight and the LiF concentration is 2000 ppm by weight, and the components are uniformly distributed in the film thickness direction. Furthermore, Se and As ₂ Se ₃ were deposited on top of them in different evaporation boats for 1.4.
Evaporate to a thickness of μm. In this case, the As concentration is 2 by weight.
%, And is uniformly distributed in the film thickness direction. This completes the vapor deposition of the amorphous semiconductor layer. Deposition of amorphous semiconductor layer is 2 × 10 ^-6
Perform in a Torr vacuum. An electron injection blocking layer is deposited on the amorphous semiconductor layer. For the electron injection blocking layer, Sb ₂ S ₃ is deposited to a thickness of 900Å in an argon atmosphere of 3 × 10 ^-1 Torr. An imaging tube incorporating the target portion formed as described above is formed, and its amorphous semiconductor layer is subjected to a charge multiplication effect of 7 × 10.
Operate in an electric field of ⁷ V / m to 2 × 10 ⁸ V / m.

Example 37. A light-transmitting electrode mainly composed of indium oxide was formed on a glass substrate, and CeO ₂ was used as a rectifying contact-assisting layer in an amount of 300
Evaporate to a thickness of Å in a vacuum of 3 × 10 ^-6 Torr. First, as an amorphous semiconductor layer, Se and As ₂ Se ₃ are vapor-deposited to a thickness of 1.4 μm by separate vapor deposition boats. In this case, the As concentration is 3% by weight, and is distributed uniformly in the film thickness direction. Subsequently, Se, As ₂ Se ₃ , and In ₂ O ₃ are vapor-deposited to a thickness of 1000Å from separate vapor deposition boats. At this time, the As concentration is 3% by weight and In
_The weight ratio of ₂ O ₃ is set to 500 ppm and is uniformly distributed in the film thickness direction. This completes the vapor deposition of the amorphous semiconductor layer. Deposition of the amorphous semiconductor layer is performed in a vacuum of 2 × 10 ^-6 Torr. Sb ₂ S ₃ is deposited as an electron injection blocking layer on the amorphous semiconductor layer to a thickness of 900Å in an argon atmosphere of 3 × 10 ^-1 Torr. An imaging tube incorporating the target portion formed as described above is formed, and its amorphous semiconductor layer is subjected to a charge multiplication effect of 7 × 10.
Operate in an electric field of ⁷ V / m to 2 × 10 ⁸ V / m.

Example 38. On a glass substrate, a transparent electrode containing tin oxide as a main component was formed, and GeO ₂ was added as 200 Å as a rectifying contact auxiliary layer, CeO ₂ .
Evaporate ₂ to a thickness of 200Å in a vacuum of 3 × 10 ^-6 Torr. An amorphous semiconductor layer is vapor-deposited thereon. For the amorphous semiconductor layer, first, Se and As ₂ Se ₃ were each heated to 300 Å by separate vapor deposition boats.
Evaporated to a thickness of. At this time, the As concentration is set to 6% by weight and is uniformly distributed in the film thickness direction. Subsequently, Se, As ₂ Se ₃ , and LiF are vapor-deposited to a thickness of 600 Å by separate vapor deposition boats. In this case, the As concentration is 2% by weight and the LiF concentration is 4000 ppm by weight, and the LiF is uniformly distributed in the film thickness direction. Then Se,
As ₂ Se ₃ is vapor-deposited to a thickness of 1.5 μm from each vapor deposition boat. In this case, the As concentration is 2% by weight, and is distributed uniformly in the film thickness direction. Se, As ₂ Se ₃ , and In ₂ O ₃ are vapor-deposited on each of them from separate vapor deposition boats to a thickness of 2000Å. At this time, the As concentration is 3% by weight and the In ₂ O ₃ concentration is 700 ppm by weight so that the As concentration is evenly distributed in the film thickness direction. On top of that, Se and As ₂ Se ₃ were each 2,000
Evaporate to a thickness of Å. In this case, the As concentration is 2% by weight.
And uniformly distribute in the film thickness direction. This completes the vapor deposition of the amorphous semiconductor layer. Deposition of amorphous semiconductor layer is 3 × 10 ^-6 Torr
In vacuum. Sb ₂ S ₃ is used as an electron injection blocking layer on the amorphous semiconductor layer in an argon atmosphere of 2 × 10 ^-1 Torr.
Evaporate to a thickness of Å. An image pickup tube incorporating the target portion formed as described above is formed, and the amorphous semiconductor layer is operated in an electric field of 7 × 10 ⁷ V / m to 2 × 10 ⁸ V / m which causes a charge multiplication effect.

Example 39. A light-transmitting electrode mainly containing indium oxide was formed on a glass substrate, and further CeO ₂ was used as a rectifying contact auxiliary layer in an amount of 200
Evaporate to a thickness of Å in a vacuum of 3 × 10 ^-6 Torr. An amorphous semiconductor layer is vapor-deposited thereon. First, the amorphous semiconductor layer is Se, A
Deposit s ₂ Se ₃ from separate vapor deposition boats to a thickness of 5000Å. At this time, the As concentration is set to 3% by weight and is uniformly distributed in the film thickness direction. Then, Se and As ₂ Se ₃ are vapor-deposited from separate vapor deposition boats to a thickness of 300Å. In this case, the As concentration is 20% by weight, and is distributed uniformly in the film thickness direction. Next, Se, As ₂ Se
Evaporate ₃ from separate evaporation boats to a thickness of 5000Å. In this case, the As concentration is 3% by weight, and is distributed uniformly in the film thickness direction. Se, As ₂ Se ₃ on top of it from separate evaporation boats 3
Evaporate to a thickness of 00Å. At this time, the As concentration is 20% by weight.
And uniformly distribute in the film thickness direction. On top of that, Se, A
Deposit s ₂ Se ₃ from separate vapor deposition boats to a thickness of 5000Å. In this case, the As concentration is set to 10% by weight and is uniformly distributed in the film thickness direction. This completes the vapor deposition of the amorphous semiconductor layer.
Deposition of the amorphous semiconductor layer is performed in a vacuum of 3 × 10 ^-6 Torr.
An electron injection blocking layer is deposited on the amorphous semiconductor layer. For the electron injection blocking layer, Sb ₂ S ₃ is deposited to a thickness of 900 Å in an argon atmosphere of 3 × 10 ^-1 Torr. An image pickup tube incorporating the target portion formed as described above is formed, and its amorphous semiconductor layer is subjected to a charge multiplication effect of 5 × 10 ⁷ V / m to 2 × 10 ⁸ V / m.
Operate in the electric field of.

Example 40. A transparent electrode composed mainly of tin oxide was formed on a glass substrate, and GeO ₂ was added as a rectifying contact auxiliary layer to 150Å, CeO ₂ .
Evaporate ₂ to a thickness of 150Å in a vacuum of 2 × 10 ^-6 Torr. An amorphous semiconductor layer is vapor-deposited thereon. For the amorphous semiconductor layer, Se and As ₂ Se ₃ are first vapor-deposited in a thickness of 600 Å from separate vapor deposition boats. At this time, the As concentration is set to 3% by weight and is uniformly distributed in the film thickness direction. Subsequently, Se and As ₂ Se ₃ are vapor-deposited to a thickness of 150 Å from separate vapor deposition boats. In this case, the As concentration is set to 10% by weight and is uniformly distributed in the film thickness direction. Then Se, Te,
As ₂ Se ₃ and LiF are vapor-deposited to a thickness of 900Å by separate vapor deposition boats. In this case, Te concentration is 15% by weight, As
The concentration is 2% by weight and the LiF concentration is 4000 ppm by weight, and the components are evenly distributed in the film thickness direction. On top of that, Se, As ₂ Se ₃ , In ₂ O ₃
Is vapor-deposited to a thickness of 150 Å using separate vapor deposition boats. At this time, the As concentration is 25% by weight and the In ₂ O ₃ concentration is 500 ppm by weight, and the As is uniformly distributed in the film thickness direction. Further, Se and As ₂ Se ₃ are vapor-deposited thereon with a thickness of 1.8 μm from separate vapor deposition boats. In this case, the As concentration is 2% by weight, and is distributed uniformly in the film thickness direction. This completes the vapor deposition of the amorphous semiconductor layer. Deposition of the amorphous semiconductor layer is performed in a vacuum of 2 × 10 ^-6 Torr. Next, an electron injection blocking layer is deposited on the amorphous semiconductor layer. The electron injection blocking layer is formed by depositing Sb ₂ S ₃ to a thickness of 1000Å in an argon atmosphere of 3 × 10 ^-1 Torr. An imaging tube incorporating the target section formed as described above is formed,
The amorphous semiconductor layer has a charge multiplication effect of 5 × 10 ⁷ V / m
Operate in an electric field of ~ 2 x 10 ⁸ V / m.

Example 41. A transparent electrode mainly composed of indium oxide was formed on a glass substrate, and further CeO ₂ was used as a rectifying contact auxiliary layer in an amount of 200
Evaporate to a thickness of Å in a vacuum of 3 × 10 ^-6 Torr. An amorphous semiconductor layer is vapor-deposited thereon. First, the amorphous semiconductor layer is Se, A
Evaporate s ₂ Se ₃ from separate evaporation boats to a thickness of 2000Å. At this time, the As concentration is set to 3% by weight and is uniformly distributed in the film thickness direction. Subsequently, Se, As ₂ Se ₃ , and LiF are vapor-deposited to the thickness of 500 Å from separate vapor deposition boats. As in this case
The concentration is 1% by weight and the LiF concentration is 2000 ppm by weight, and the components are evenly distributed in the film thickness direction. Next, Se, As ₂ Se ₃ , and Te are vapor-deposited from separate vapor deposition boats to a thickness of 1 μm. In this case, the As concentration is 1% by weight, and is distributed uniformly in the film thickness direction. Further, the Te concentration is increased with a uniform gradient over the film thickness of 1 μm so that the concentration at the start of Te vapor deposition is 1% by weight and the concentration at the end of Te vapor deposition is 15% by weight. Then Se, As ₂ Se ₃
To a thickness of 150Å in separate evaporation boats. In this case, the As concentration is 20% by weight, and is distributed uniformly in the film thickness direction. On top of that, Se, As ₂ Se ₃ 2500 from separate evaporation boats.
Evaporate to a thickness of Å. At this time, the As concentration is 2% by weight, and the As concentration is uniformly distributed in the film thickness direction. This completes the vapor deposition of the amorphous semiconductor layer. Deposition of the amorphous semiconductor layer is performed in a vacuum of 2 × 10 ^-6 Torr. Sb ₂ S ₃ is deposited on the amorphous semiconductor layer as an electron injection blocking layer to a thickness of 900Å in an argon atmosphere of 2 × 10 ^-1 Torr. An image pickup tube incorporating the target portion formed as described above is formed, and the amorphous semiconductor layer is operated in an electric field of 6 × 10 ⁷ V / m to 2 × 10 ⁸ V / m which causes a charge multiplication effect.

Example 42. A transparent electrode mainly composed of tin oxide is formed on a glass substrate, and a hydrogenated amorphous silicon nitride film is formed to a thickness of 200 Å by a glow discharge method as a rectifying contact auxiliary layer. . Se and As ₂ Se ₃ were deposited on top of them by separate evaporation boats at 150Å
Evaporated to a thickness of. In this case, the As concentration is set to 30% by weight and is uniformly distributed in the film thickness direction. On top of that, Se, As ₂
Se ₃ is vapor-deposited to a thickness of 1.8 μm by a separate vapor deposition boat. At this time, the As concentration is 2% by weight, and the As concentration is uniformly distributed in the film thickness direction. Deposition of Se, As ₂ Se _{3 on} the amorphous semiconductor layer is 3
Performed in a vacuum of × 10 ^-6 Torr. Subsequently, an electron injection blocking layer is deposited. The electron injection blocking layer is formed by depositing Sb ₂ S ₃ to a thickness of 1000Å in an argon atmosphere of 3 × 10 ^-1 Torr. An image pickup tube incorporating the target portion formed as described above is formed, and the amorphous semiconductor layer thereof has a charge multiplication effect of 6 × 10 ⁷ V / m
It is operated with an electric field of 2 × 10 ⁸ V / m.

Example 43. A transparent electrode mainly containing tin oxide is formed on a glass substrate. Next, an amorphous semiconductor layer is deposited. For the amorphous semiconductor layer, Se is first deposited to a thickness of 1000Å. Then, Se and LiF are vapor-deposited to a thickness of 1000 Å from separate vapor deposition boats. At this time, the LiF concentration is 3000 ppm in weight ratio, and is uniformly distributed in the film thickness direction. Further, Se is vapor-deposited thereon to a thickness of 1.8 μm. This completes the vapor deposition of the amorphous semiconductor layer. Deposition of the amorphous semiconductor layer is performed in a vacuum of 2 × 10 ^-6 Torr. An electron injection blocking layer is deposited on the amorphous semiconductor layer. The electron injection blocking layer is Sb ₂ S ₃ 100 in an argon atmosphere of 3 × 10 ^-1 Torr.
Evaporate to a thickness of 0Å. An image pickup tube incorporating the target portion formed as described above is formed, and the amorphous semiconductor layer is operated in an electric field of 7 × 10 ⁷ V / m to 2 × 10 ⁸ V / m which causes a charge multiplication effect.

〔The invention's effect〕

As is apparent from the above, according to the present invention, it is possible to obtain a high-sensitivity image pickup tube having a gain of more than 1 and its operating method without degrading the afterimage characteristic.

Although the present invention has been made with respect to an image pickup tube,
It goes without saying that the present invention can be applied to a light receiving element using a method of reading a signal charge by an electronic switch or the like or a light receiving element for optical communication.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a principle configuration of an image pickup tube according to the present invention,
FIG. 2 is a diagram showing an example of the principle configuration of a target portion of an image pickup tube according to the present invention, and FIGS. 3, 4, 5, 6, and 7 are targets of the image pickup tube according to the present invention. Showing characteristics of parts, FIGS. 8 and 9 are diagrams showing an example of a principle structure of a target part of an image pickup tube according to the present invention, and FIG. 10 is a camera formed by using the image pickup tube according to the present invention. It is a figure which shows the basic composition of. Explanation of symbols 1,21,81,91 …… Transparent substrate, 2,22,82,92 …… Transparent electrode, 3 …… Photoconductive film, 24,84,94
…… Amorphous semiconductor layer, 86,96 …… Photo carrier generation layer, 97 …… Intermediate layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (31) Priority claim number Japanese Patent Application No. Sho 62-4856 (32) Priority date Sho 62 (1987) January 14 (33) Priority claim country Japan (JP) (31) Priority Claim No. Japanese Patent Application No. 62-4871 (32) Priority Date Sho 62 (1987) January 14 (33) Country of priority claim Japan (JP) (31) Priority claim number Japanese Patent Application No. 62-4872 (32) Priority Japan Sho 62 (1987) January 14 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. Sho 62-4873 (32) Priority date Sho 62 (1987) January 14 (33) ) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. Sho 62-4875 (32) Priority date Sho 62 (1987) January 14 (33) Priority claiming country Japan (JP) Accelerated examination Application (72) Inventor Tatsuro Kawamura 1-101-1 Kinuta, Setagaya-ku, Tokyo Inside the Broadcasting Technology Laboratory, Japan Broadcasting Corporation (72) Inventor Junichi Yamazaki Setagaya, Tokyo 1-10-1 Kukina, Broadcasting Technology Research Institute of Japan Broadcasting Corporation (72) Inventor Eihisa Shinma 1-10-1 Kinota, Setagaya-ku, Tokyo Broadcasting Research Institute of Japan Broadcasting Association (72) Inventor Kazuhisa Taketoshi 1-10-1 Kinuta, Setagaya-ku, Tokyo Within the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Shiro Suzuki 1-10-1 Kinuta, Setagaya-ku, Tokyo Within the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Takashi Yamashita 1-101-1 Kinuta, Setagaya-ku, Tokyo Within the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Mitsuo Kosugi 1-10-1 Kinuta, Setagaya-ku, Tokyo Within the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Yoshizumi Ikeda 1-10-1, Kinuta, Setagaya-ku, Tokyo Inside Broadcasting Technology Research Institute, Japan Broadcasting Corporation (72) Inventor Masaaki Aiba 1-1-10 Kinuta, Setagaya-ku, Tokyo Broadcasting technology research In-house (72) Inventor Tadaaki Hirai 1-280 Higashi Koigakubo, Kokubunji City, Tokyo Hitachi Co., Ltd. Central Research Laboratory (72) Inventor Yukio Takasaki 1-280 Higashi Koigakubo, Kokubunji, Tokyo Hitachi Central Research Laboratory (72) Inventor Yoshio Ishioka 1-280 Higashi Koigakubo, Kokubunji, Tokyo Hitachi Central Research Laboratory ( 72) Inventor Tatsuo Makishima 1-280, Higashi Koigakubo, Kokubunji, Tokyo, Central Research Laboratory, Hitachi, Ltd. (72) Inventor Kenji Samejima 1-280, Higashi Koigakubo, Kokubunji, Tokyo (72) Inventor, Central Research Laboratory (72) Takeshi Uda 1-280, Higashi Koigakubo, Kokubunji, Tokyo Inside the Basic Research Laboratory, Hitachi, Ltd. (72) Inventor Naohiro Goto 3300 Hayano, Mobara, Chiba Prefecture Inside the Mobara Plant, Hitachi, Ltd. (72) Inventor Nonaka Ikumitsu, Mobara, Chiba 3300 Hayano, Shimohara, Hitachi, Ltd. (72) Inventor, Eisuke Inoue 3300, Hayano, Mobara, Chiba, Hitachi, Ltd., Mobara, Ltd. (56) References JP-A-61-2223 83 (JP, A) JP 62-2435 (JP, A) JP 63-19738 (JP, A)

Claims (16)

[Claims] 1. A target portion formed by forming a transparent electrode and a photoconductive film for photoelectrically converting incident light on a transparent substrate, and an electron beam generating portion for scanning the target portion. An image pickup tube having a rectifying contact for preventing injection of holes from the transparent electrode into the photoconductive film under an electric field in which avalanche multiplication occurs in the photoconductive film, In addition, the photoconductive film has an amorphous semiconductor layer containing selenium as a main component, and the translucent electrode reads the avalanche-multiplied charge generated in the amorphous semiconductor layer by incident light. An image pickup tube characterized in that 2. The image pickup tube according to claim 1, wherein the amorphous semiconductor layer has a film thickness of 0.5 μm or more and 10 μm or less. 3. The image pickup tube according to claim 1 or 2, wherein the amorphous semiconductor layer contains one or both of As and Ge. 4. The imaging tube according to claim 1, 2, or 3, wherein the amorphous semiconductor layer is formed of Te, Sb, Cd in at least a part of its thickness direction. , Bi containing at least one selected from Bi. 5. The image pickup tube according to claim 4, wherein the region is provided in the amorphous semiconductor layer away from the transparent electrode. 6. The image pickup tube according to claim 4 or 5, wherein Te, Sb, Cd, Bi contained in the region.
An image pickup tube characterized in that the content of at least one selected from the above in the amorphous semiconductor layer is 0.01% by weight or more and 50% by weight or less on average. 7. Claims 1st, 2nd, 3rd,
In the image pickup tube according to item 4, item 5 or item 6,
An image pickup tube, wherein the amorphous semiconductor layer contains a substance that forms a hole trap level in at least a part of its thickness direction. 8. The imaging tube according to claim 7, wherein the substance that forms the hole trap level is Li, Na, K, Mg, Ca,
An image pickup tube characterized by being at least one selected from the group consisting of Ba, Tl and their fluorides, and fluorides of Al, Cr, Mn, Co, Pb, Ce. 9. The image pickup tube according to claim 7, wherein the substance that forms the hole trap level is contained in a part of the amorphous semiconductor layer on the light incident side. An image pickup tube characterized by. 10. The imaging tube according to claim 7, 8, or 9, wherein the local concentration of the substance that forms the hole trap level in the amorphous semiconductor layer is An image pickup tube characterized in that the content is 20 ppm by weight or more and 10% by weight or less. 11. The imaging tube according to any one of claims 1 to 10, wherein the amorphous semiconductor layer forms an electron trap level in at least part of its thickness direction. An image pickup tube characterized by containing a substance. 12. The imaging tube according to claim 11, wherein the substance forming the electron trap level is copper oxide, indium oxide, selenium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, gallium fluoride, An image pickup tube characterized by being at least one selected from the group consisting of indium fluoride, Zn, Ga, In, Cl, I and Br. 13. The imaging tube according to claim 11 or 12, wherein the substance forming the electron trap level is contained in a part of the amorphous semiconductor layer in the vicinity of the electron beam scanning side. An image pickup tube characterized by the above. 14. The imaging tube according to claim 11, 12, or 13, wherein the local concentration of the substance forming the electron trap level in the amorphous semiconductor layer is 20. An image pickup tube characterized by being in the range of ppm to 10% by weight. 15. A target portion having an amorphous semiconductor layer containing selenium as a main component in at least a part of a photoconductive film, and the photoconductive film having rectifying contact in an electric field region where avalanche multiplication occurs. A method of operating an image pickup tube having the same, wherein the photoconductive film is operated in an electric field region that exhibits the charge multiplication capability inside the amorphous semiconductor layer. 16. The method of operating an image pickup tube according to claim 15, wherein the electric field region is from 5 × 10 ⁷ V / m to 2 × 10 7.
^A method of operating an image pickup tube, which is in the range of ⁸ V / m.