JPH0696688A - Image pickup tube and operation method therefor - Google Patents

Abstract

PURPOSE:To provide an image pickup tube having high sensitivity, generating less afterimage and small dark current, and further having sensitivity even for incident light of long wavelength. CONSTITUTION:A photo-conductive film having a blocking type contact is constituted of a light carrier generation layer 86 for absorbing incident light and generating most of light carriers, and an electric charge multiplying layer 84 consisting of an amorphous semiconductor and having the capability of multiplying the generated light carriers. Also, this tube is operated in an electrical field zone where electrical charge is multiplied in the amorphous semiconductor.

Description

Detailed Description of the Invention

[0001]

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 an image pickup tube made of a photoconductive film having a blocking contact whose sensitivity is remarkably enhanced while maintaining good photoresponse characteristics. Regarding the operation method.

[0002]

2. Description of the Related Art As is already known, a target used in a photoconductive type image pickup tube is a so-called blocking type target (for example, a blocking type target) having a structure in which charge injection from a signal electrode side and an electron beam scanning side is blocked. (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-type 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, and the single crystal of np structure is already available. A high-sensitivity imaging tube using a semiconductor target plate (Japanese Patent No. 571503) and an electron injection recombination layer for injecting scanning electrons and recombination of scanning electrons and holes are provided on the beam scanning side of the photoconductive layer. A high-sensitivity image pickup tube target (Japanese Patent Application No. 60-140288) has been proposed.

[0004]

However, in all of the above-mentioned prior arts in which the sensitivity of the photoconductive type image pickup tube target is increased to a gain greater than 1, a part of scanning electrons is injected into the image pickup tube target. Therefore, in principle, there is a problem that the effective storage capacity of the target increases and the afterimage increases.

Further, in the image pickup tube having the "semiconductor target plate" described in the above-mentioned Japanese Patent No. 571503, the scanning electrons reaching the p-type single crystal semiconductor layer pass through the n-type single crystal semiconductor layer to form a signal electrode. The average running time to reach T
When the average life time of electrons in the t, p-type single crystal semiconductor layer is Tn, and the scanning time of one pixel of the scanning electron beam is Te, there are restrictions such as the requirement of Tt <Tn < Te. In addition to the difficulty of obtaining the single crystal semiconductor substrate, the single resistance of the substrate is low when Si single crystal is used as the single crystal substrate. Had to be separated into a mosaic shape, which was not preferable for improving the resolution of the image pickup tube.

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

[0007]

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

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

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 block diagram of the target portion of the image pickup tube according to the present invention. Transparent substrate 21, transparent electrode 2
2, the amorphous semiconductor layer 24 and the electron injection blocking layer 25 are shown.

When sufficient rectifying contact cannot be obtained between the transparent electrode 22 and the photoconductive film 24, the rectifying contact auxiliary layer 2
It is also effective to interpose 3 to enhance the function of rectifying contact.

By utilizing the phenomenon that a charge multiplication action occurs in the amorphous semiconductor layer when a strong electric field is applied to the amorphous semiconductor layer, a target structure is made to effectively generate such an operation. This makes it possible to obtain an image pickup tube having a high sensitivity with a gain of greater than 1 without increasing the afterimage.

In particular, 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, 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 comprises a transparent substrate 1, a transparent electrode 2,
The electron beam 6 is used by using the target portion made of the photoconductive film 3.
It is produced by vacuum-sealing the electrode groups 4, 9 and 10 for emitting, accelerating and deflecting and focusing the light in the glass casing 5.

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 to become the electron beam 6 and become the surface of the photoconductive film 3. To scan. 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. Light 11 in this state
When the light is emitted, 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 usually 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,
As described above, the potential difference across the charged photoconductive film 3 is reduced.

Next, when the electron beam 6 scans, 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. 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 light of the same intensity,
Along with this, the current flowing in the process of recharging increases. 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 multiplication effect inside, the function of rectifying contact, that is, hole injection blocking becomes insufficient, or
There are drawbacks that white defects are likely to occur, or the function of blocking electron injection from the scanning beam is insufficient, dark current increases, and image quality deteriorates. 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 of all, the present inventors have found that at least a part of the amorphous semiconductor layer mainly composed of Se is used for the purpose of enhancing the hole injection blocking function and suppressing the generation of scratches. It has been found that it is effective to include a substance that forms a hole trap level in the layer. Further, as a substance that forms a hole trap level in such an amorphous semiconductor layer, Li, N
At least one selected from the group consisting of a, K, Mg, Ca, Ba, Tl and their fluorides, and fluorides of Al, Cr, Mn, Co, Pb and Ce is extremely effective. Of these, for fluoride, LiF, Na
F, MgF ₂ , CaF ₂ , BaF ₂ , AlF ₃ , CrF ₃ ,
It may have a stoichiometric composition such as MnF ₂ , CoF ₂ , PbF ₂ , CaF 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. No, 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, it relaxes the electric field near the electrode interface without impairing the charge multiplication function. Therefore, it was revealed that the effect is remarkable.

What is important is a substance having a blocking structure, which forms a hole trap level in at least a part of the amorphous semiconductor layer forming the photoconductive film in the amorphous semiconductor layer. Of at least one of them.

FIG. 5 shows the occurrence of scratches in a target in which 2000 wt ppm of LiF is contained in a part of an amorphous semiconductor layer mainly composed of Se, in comparison with the case of a target in which LiF is not added. It is a thing. 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 if the added amount is small, and if the added amount is too large, the amorphous semiconductor layer is added. The electric field in the inside may fluctuate easily, which may cause seizure. Therefore, it is desirable that the local concentration of the additive substance in the film thickness direction in the amorphous semiconductor layer is 20 ppm by weight or more and 10% by weight or less.

Furthermore, in the case of applying a strong electric field to the amorphous semiconductor layer mainly composed of Se so as to cause a charge multiplying effect inside, the inventors of the present invention enhance the blocking function against the scanning electron beam. It has been found that it is effective to make at least part of the amorphous 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.

Examples of the substance that forms an electron trap level in the amorphous semiconductor layer are copper oxide, indium oxide, selenium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, gallium fluoride and indium fluoride. ，
It has been found that at least one selected from the group consisting of Zn, Ga, In, Cl, I and Br is extremely effective.

Regarding oxides and fluorides, Cu
O, In ₂ O ₃ , SeO ₂ , V ₂ O ₅ , MoO ₃ , WO ₃ , G
It may have a stoichiometric composition such as aF 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 impair the charge multiplication function when such a substance forming an electron trap level in the amorphous semiconductor layer is added near the electron beam scanning side. Since the electric field in the vicinity of the electron beam scanning side can be relaxed without any problem, the effect is remarkable, and the added substance is always distributed at a uniform concentration in the film thickness direction of the photoconductive layer. It was found that it is not necessary and that it is acceptable to have a change in concentration. The effect of the present invention is not sufficient when the concentration of the substance forming the electron trap level added to at least a part of the amorphous semiconductor layer mainly composed of Se in the film thickness direction is low, and If the amount is too large, baking may occur easily.

Therefore, the local concentration in the film 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. desirable.

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, it is apparent that the effect can be further enhanced by adding a substance that forms the electron trap level and forming a layer in which at least one of As and Ge is added at least in a part near the electron beam scanning side. Became.

[0030]

[Table 1]

Table 1 shows a target portion (I) containing 2000 wt ppm of indium oxide and 38.8 wt% of As in 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. 4) shows a comparison between the dark current characteristic in () and the dark current characteristic of the 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 the substance forming the hole trap level in the amorphous semiconductor layer and the means for adding the substance forming the electron trap level may be used in combination.

Further, FIG. 6 shows a target applied to obtain 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 figure which shows the voltage and the relationship of dark current at the time of the said target voltage application, and film thickness. From the figure, when the film thickness of the amorphous semiconductor layer becomes 0.5 μm or less,
It can be seen that the dark current increases rapidly. Therefore, the thickness of this amorphous semiconductor layer is preferably 0.5 μm or more.

On the other hand, as the film thickness becomes thicker, the target applied voltage required to obtain a gain larger than 1 becomes high, and a rippled pattern around the screen (hereinafter referred to as "ripple phenomenon").
Is likely to occur. As described above, the abnormal phenomenon is likely to occur when the applied voltage is 700 V or higher. Therefore, from the figure, it is understood that the thickness of the amorphous semiconductor layer is preferably 10 μm or less in practical use.

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 may have a structure in which two or more different types of amorphous semiconductor layers having a charge multiplication function are deposited. Alternatively, 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 containing Se is used for the amorphous semiconductor layer, a long wavelength of the incident light capable of absorbing the incident light and generating photocarriers, that is, electron-hole pairs is obtained. The side limit is limited by the energy gap of amorphous Se. Further, the 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 and disappears before becoming a signal current. This phenomenon is 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 action 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 inventors of the present invention, Te, Sb, at least a part of the amorphous semiconductor layer mainly composed of Se,
It has been clarified that when at least one of Cd and Bi is added, the charge multiplication effect is maintained and high sensitivity can be easily obtained even for long wavelength light. At this time, Se
The concentration of the element added to the amorphous semiconductor layer mainly composed of does not have to be constant in the film thickness direction, and may have a concentration distribution. FIG. 7 shows an example of the relationship between the sensitivity to long-wavelength light and the average Te doping concentration obtained under the same operating conditions. As is clear from the figure, the sensitivity to long-wavelength light increases as the Te concentration increases, and it is clear that the addition of Te is extremely effective. It is necessary to add at least one of Te, Sb, Cd and Bi. The concentration of the substance to be added should be selected according to the use of the image pickup tube, but the average value is preferably 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 value of the concentration of the added substance is 5
It should be 0% by weight or less. Further, in order to obtain stable rectification 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 photoconductive film 3 is formed on the light incident side electrode interface. It is desirable not to add the above substances.

As a second means for solving the above problems, the amorphous semiconductor layer itself is not provided with both functions of charge generation and charge multiplication, but is different from the amorphous semiconductor layer. There is a means of providing a photocarrier generation layer adjacent to the amorphous semiconductor layer in the photoconductive film. This photo carrier generation layer absorbs incident light to generate most of the photo carriers,
If this is guided to the amorphous semiconductor layer and multiplied in the amorphous semiconductor layer, the disappearance due to direct recombination of free electrons and free holes in the amorphous semiconductor layer is extremely small. It is possible to solve the 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 easily form a uniform thin film on an arbitrary photocarrier generation layer by a vacuum deposition method, and therefore has a photoconductive film using amorphous Se as a charge multiplication layer. Is extremely effective as a target portion of the image pickup tube.

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

FIG. 8 is a principle block diagram showing a target portion when the image pickup tube according to the present invention is implemented. Translucent substrate 8
1, a transparent electrode 82, a photocarrier generation layer 86 that absorbs light to generate charges, an amorphous semiconductor layer 84 that functions as a charge multiplication layer, and an electron injection blocking layer 85 are shown. Translucent electrode 8
2 and the photocarrier generation layer 86, the transparent electrode 82
In the case where sufficient rectifying contact for preventing hole injection from the photocarrier generating layer 86 to the photocarrier generating layer 86 cannot be obtained, it is also effective to interpose the rectifying contact auxiliary layer 83 to enhance the function of the rectifying contact. Is.

Needless to say, the material constituting the photocarrier generating layer has a large light absorption coefficient and a large photoelectric conversion efficiency, but it is not necessarily required to be an amorphous material, and a crystalline material is required. The material does not matter. 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, a compound having a composition different from that of the photocarrier generation layer is provided between the photocarrier generation layer and the charge multiplication layer. It is also effective to insert an intermediate layer made of a material to improve the carrier running property. As the intermediate layer, for example, an amorphous semiconductor layer mainly composed of Se, bismuth, cadmium or their chalcogenides, tellurium, tin, etc., which change the band gap, arsenic, germanium, antimony, indium, gallium or those Chalcogenide, sulfur, chlorine, iodine,
Distribution of electric field intensity in the photoconductive film by adding a substance that forms a negative space charge such as bromine, copper oxide, indium oxide, selenium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, gallium fluoride, indium fluoride It is effective to use a layer that changes.

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

FIG. 9 is a diagram showing the principle of the structure of the target portion when implementing the image pickup tube according to the present invention. Translucent substrate 9
1, a 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, and an electron injection blocking layer 95 are shown. The transparent electrode 9 is formed on the interface between the light-generating layer 96 and the photocarrier generation layer 96.
When sufficient rectifying contact for preventing hole injection from 2 to the photocarrier generating layer 96 cannot be obtained, the function of the rectifying contact may be enhanced by interposing the rectifying contact auxiliary layer 93. Effectiveness is the same as that described in the description of FIG. In FIG. 9, the position of the intermediate layer 97 described above is shown in principle.

Regarding this intermediate layer, for the purpose of changing the electric field strength in the film, it is also effective to add a trace amount of a substance capable of modulating the conduction type such as group III or group V to the amorphous semiconductor layer made of a tetrahedral material. Met.

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

First, at least one element from the first group consisting of Zn, Cd, Hg and Pb, and O,
If a carrier-forming layer is mainly composed of a combination of at least one element of the second group consisting of S, Se and Te, the carrier-generating layer can obtain a high photoelectric conversion efficiency. The optical bandgap width can be adjusted by the combination of elements and the composition ratio, and the spectral sensitivity can be controlled. Therefore, the material is extremely excellent as a material for the photocarrier generation layer.

Examples of the material of this photocarrier generation layer are ZnS, CdS, ZnSe, CdSe, ZnT.
A material mainly containing at least one of e, CdTe, HgCdTe, PbO and PbS is preferable.

Further, for example, CdSe is formed in the photocarrier generation layer.
Also, targets using CdS, ZnCdTe, CdTe, etc. are suitable for imaging in the visible light and near-infrared light regions, and 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 an X-ray image.

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

Further, as a result of a study conducted by the present inventor, a layer of the photoconductive film which absorbs incident light and generates most of photocarriers is mainly composed of an amorphous tetrahedral material, and F,
By replacing it with an amorphous semiconductor containing at least one of H and Cl and combining it with a charge multiplication layer, the problem of efficiency decrease due to photocarrier recombination inside the amorphous semiconductor layer is improved. It was found that an image pickup tube having extremely high sensitivity 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 can obtain high photoelectric conversion efficiency because the internal defects can be suppressed to a very low level. Moreover, 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 including 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 contains reactive sputtering of a tetrahedral material in an atmosphere containing halogen such as fluorine or chlorine or hydrogen, or hydride, fluoride or chloride of the tetrahedral element. It can be formed by decomposition of gas. For example, amorphous silicon containing hydrogen is deposited at 100 to 300 ° C.
And a method of reactively sputtering silicon in a mixed atmosphere of an inert gas and hydrogen, a gas containing silicon such as monosilane and disilane, plasma discharge,
It can be formed by a method of decomposing by applying energy such as light, electromagnetic field or heat.

Furthermore, by sputtering a mixture of silicon and germanium, or a mixture of silicon and carbon, or by mixing and introducing monosilane, germane containing germanium, methane containing carbon, acetylene, etc., and decomposing, the energy gap is amorphous. It is also possible to obtain an amorphous silicon-germanium compound that is narrower than amorphous silicon and an amorphous silicon-carbon compound that has an energy gap that is wider than amorphous silicon, and it is possible to adjust the spectral sensitivity characteristics of the image pickup tube.

At this time, from the amorphous silicon layer to the amorphous semiconductor layer, an intermediate layer having an energy band structure or an electric field strength changed is interposed between the amorphous silicon layer and the amorphous semiconductor layer to change the amorphous silicon layer to the amorphous semiconductor layer. It was the same as the above-mentioned case that the present invention exerts a further effect by smoothing the delivery of the optical carrier.

As the intermediate layer, a layer formed by adding a specific substance to the above-mentioned amorphous semiconductor layer mainly composed of Se, or an amorphous tetrahedral material can be modulated in conduction type such as group III or group V. Substance, germanium, carbon, nitrogen,
It was also effective to use a layer in which tin or the like is mixed to control the band gap and space charge or a combination thereof.

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

FIG. 10 shows a structural example of a monochrome camera using the image pickup tube according to the present invention. As shown in the figure, the camera amplifies an optical system 101 for forming an optical image, a deflection of an electron beam, a coil assembly 102 including a focusing coil and an image pickup tube, and a video signal current obtained from the coil assembly 102. Circuit part 10 for processing as a video signal
3. A circuit portion 104 including a deflection amplification circuit for generating a synchronizing signal and deflecting an electron beam, and a power supply portion 10.
It consists of 5.

In the case of a three-tube type color camera, as is well known, the configuration of 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 thereto. To be done. By applying the image pickup tube according to the present invention to a camera having the basic configuration shown in FIG. 10, for example, not only high-definition television images can be realized but also a wide range of image new media can be opened up. Is.

[0062]

The charge multiplication function in the amorphous semiconductor layer of the image pickup tube according to the present invention will be described with reference to FIG. In FIG. 3, a transparent N-type electrode, an amorphous Se layer, and
Is a graph showing the relationship between the output signal current and the target voltage in the target portion of the image pickup tube deposited sb ₂ S ₃ layer. The figure shows the optical signal current and applied voltage when light is applied from the transparent glass substrate side while voltage is 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 translucent N-type electrode and the amorphous Se layer, there is a rectifying action to prevent injection of holes, and S
Since the b ₂ S ₃ layer has a function of preventing scanning electrons from flowing into the amorphous Se layer, the present image pickup tube target operates as a so-called blocking 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.

The operation area C in FIG. 3 is the 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 of FIG.
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, the holes reach the electron injection blocking layer 25, and are read by the scanning electron beam. To be
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 amorphous semiconductor layer 24 does not exceed the number of incident photons, and the electric field of the amorphous semiconductor layer 24 is not sufficiently strong. The target gain is 1 because the recombination of
It is the following. 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 is required to separate most of the electron-hole pairs generated by the incident photons and allow them to run toward the transparent electrode 22 and the electron injection blocking layer 25 without recombining them. When the strength is increased, 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 amorphous semiconductor layer 24
Since the number of electron-hole pairs generated in 1 does not exceed the number of incident photons, 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, the area C in FIG. 3 which is the operation area of the image pickup tube according to the present invention will be described. When the present inventors further strengthen the target electric field from the above-mentioned region B,
In the amorphous semiconductor layer 24 of FIG. 2, a charge multiplication effect occurs,
It has been found that the effect that the signal current rapidly increases and the gain becomes 1 or more can be obtained. The present invention aims to increase the sensitivity of the photoconductive film used in the target portion of the image pickup tube by utilizing the effect of charge multiplication that occurs in the region C of the above operation.

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, no increase in the afterimage is recognized in the region C of the present invention in which the gain is 1 or more as compared with the region B, and among the regions C Since the increase in dark current is small except for the electric field region where the gain is extremely high, the charge multiplication action in the image pickup tube according to the present invention is not the amplification action due to the charge injection described in the section of the prior art. It is clear that this is an amplification effect which has not been heretofore known, which 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 Problems]. When light is irradiated from the glass substrate side of the image pickup tube target in this state, most of the incident light is absorbed mainly by 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.

Such a charge multiplication effect when a high electric field is applied is already known as an avalanche amplification phenomenon in a crystalline semiconductor, but microplasma is generated in the crystalline semiconductor, and a dark current is 10 ⁻⁹ A /. There is no example that has been practically used as a two-dimensional photoelectric conversion device such as an image pickup tube due to the problem that the dark current cannot be suppressed to a low level when the device has a large area of mm ² and a large cross-sectional area. 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, and in fact, there has been no disclosure example of the amplification phenomenon in the amorphous semiconductor. However, as a result of a detailed study by the present inventors, it was discovered that the amorphous semiconductor has a charge multiplication effect, and the dark current is 1/100 or less of that of the crystalline semiconductor despite its large area. .

Further, according to a detailed examination by the inventors, the charge multiplication effect in the amorphous semiconductor is very remarkable for the holes, while it is small for the electrons. I knew it was. 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 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.

[0073]

EXAMPLES The present invention will be described in detail below with reference to examples. The image pickup tube according to the present invention is configured as shown in FIG.

Example 1 A transparent electrode mainly composed of tin oxide was formed on a glass substrate, and amorphous Se was formed on the transparent electrode to a thickness of 0.1 to 6 μm. Vacuum deposition is performed to form an amorphous semiconductor layer. Sb ₂ S ₃ was deposited as an electron injection blocking layer on amorphous Se to a thickness of 1000 Å in an inert gas atmosphere of 2 × 10 ^-1 Torr to form a target portion of a photoconductive image pickup tube having a blocking structure. To get

(Embodiment 2) A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and Se and As or Se and Ge having a film thickness of 0.1 are formed on the transparent electrode. An amorphous semiconductor layer having a thickness of 1 to 6 μm is formed by a vacuum evaporation method. In forming a film, Se and As ₂ Se ₃ or Se and Ge are simultaneously evaporated from different boats and deposited on a substrate so that the concentration of As or Ge is 2% by weight on average. Sb ₂ S ₃ as an electron injection blocking layer is further formed thereon in an inert gas atmosphere of 1 × 10 ^-1 Torr.
It is vapor-deposited to a thickness of 00Å 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 Se was formed on the transparent electrode.
And an amorphous semiconductor layer made of As and Ge and having a film thickness of 0.5 to 6 μm is formed. For film formation, Se, As ₂ S
e ₃ and GeSe are simultaneously evaporated from different boats and deposited on the substrate, and the total amount of As and Ge is 3% by weight on average.
So that Further, Sb ₂ S ₃ as an electron injection blocking layer is vapor-deposited thereon to a thickness of 800Å 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.

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. 8 x 1 for the obtained image pickup tube
When operated with a target electric field of 0 ⁷ V / m or more, signal amplification occurs in the amorphous semiconductor layer, and for example, 1.2 × 10 ⁸
An output with a gain of about 10 is obtained at V / m.

In Examples 1, 2 and 3, a rectified contact auxiliary layer, for example, a cerium oxide vacuum-deposited film having a film thickness of 300 Å is interposed between the transparent electrode and the amorphous semiconductor layer. You can also In this case, since the function of blocking the injection of holes from the transparent electrode is improved, the device can be operated in a higher electric field and the sensitivity of the charge multiplication factor of 10 or more can be obtained.

(Example 4) A transparent electrode composed mainly of tin oxide was formed on a glass substrate, and an amorphous Se layer having a thickness of 1 to 3 μm was formed on the transparent electrode by an evaporation method. To form an amorphous semiconductor layer. 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 image pickup tube having a blocking structure. .

Example 5 A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and CeO ₂ is vapor-deposited to a thickness of 0.03 μm on the transparent electrode. An amorphous Se layer having a thickness of 0.5 to 2 μm is formed thereon by a vacuum evaporation method to form an amorphous semiconductor layer. Sb ₂ S ₃ as an electron injection blocking layer is further formed thereon with 1 × 10 ⁻¹ Torr.
To a thickness of 0.1 μm in an inert gas atmosphere to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

(Example 6) A transparent electrode containing tin oxide as a main component is formed on a glass substrate. 0.015 μm of GeO ₂ and 0.015 of CeO ₂ were sequentially deposited on the transparent electrode.
Evaporate to a thickness of μm. Then, by vacuum deposition,
An amorphous Se layer having a thickness of 02 to 0.06 μm is also formed.
Next, Se and LiF are evaporated from separate boats to form an amorphous layer having a thickness of 0.02 to 0.06 μm.
At this time, the concentration of LiF is set to 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 to have a total film thickness of 1 to 8 μm. 2 × 10 of Sb ₂ S ₃ was formed as an electron injection blocking layer on the amorphous Se layer.
^By vapor deposition to a thickness of 0.1 μm in an inert gas atmosphere of ⁻¹ Torr, a target portion of a photoconductive type image pickup tube having a blocking structure is obtained.

Example 7 A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and CeO is formed thereon.
₂ is vapor-deposited to a thickness of 0.03 μm. Further on it S
e, As and LiF film thickness 0.02 to 0.04 μm
The amorphous semiconductor layer of is formed by a vacuum evaporation method. In forming a film, Se, As ₂ Se ₃ and LiF are simultaneously evaporated from different boats to be vapor-deposited, and the concentration of As is 3 to 6% by weight and the concentration of LiF is 3000 to 60 on average.
It should be 00 ppm by weight. On top of that, Se, As
And an amorphous semiconductor layer made of LiF and having a film thickness of 0.03 to 0.045 μm is formed by a vacuum evaporation method. At this time
The concentration is 2 to 5 wt%, and the LiF concentration is 15000 wt ppm on average. An amorphous semiconductor layer made of Se and As is formed thereon by a vacuum vapor deposition method and the total film thickness is 1 to 4 μm.
m. At this time, the As concentration is 1 to 3% by weight. Sb ₂ S ₃ was added as an electron injection blocking layer on top of this with 1 × 10 ⁻¹ To
Vapor deposition is performed in an inert gas atmosphere of rr to a thickness of 0.1 μm to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

(Embodiment 8) A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and Se is deposited on the transparent electrode.
And an amorphous semiconductor layer made of LiF and having a film thickness of 0.02 to 0.03 μm is formed by a vacuum evaporation method. When forming a film, Se and LiF are simultaneously evaporated from different boats to be vapor-deposited, and the concentration of LiF is 2000 wt.
pm. 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 vapor deposition method. The concentration of LiF at this time was 80 on average.
It is set to 00 to 15000 weight ppm. Further Se and Te
From each separate boat to a film thickness of 0.02
An amorphous semiconductor layer having a thickness of 0.04 μm is formed. At this time, T
The e concentration is 5 to 15% by weight. Next, such amorphous S
The e layer is formed by the vacuum deposition method and the total film thickness is 1 to 4 μm.
The thickness of. Further, Sb ₂ S ₃ as an electron injection blocking layer was vapor-deposited to a thickness of 0.08 μm in an inert gas atmosphere of 2 × 10 ⁻¹ Torr to form a target portion of the photoconductive type imaging tube having the blocking type structure. obtain.

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. The obtained image pickup tube is 7
When operated in an electric field of × 10 ⁷ V / m or more, signal amplification occurs in the amorphous photoconductive layer. For example, in the case of a target having a film thickness of 2 μm, the gain is 10 or more at 1.2 × 10 ⁸ V / m. Output was obtained.

(Embodiment 9) A transparent electrode containing tin oxide as a main component is formed on a glass substrate, and Se and Te are further provided on the transparent electrode by 1-2 μ from separate boats.
Vacuum deposition is performed to a thickness of m. At this time, the Te concentration is set to 0.01% by weight and is uniformly distributed in the film thickness direction. An Sb layer serving as an electron injection blocking layer is formed on the amorphous semiconductor layer mainly composed of Se.
0.1 in an inert gas atmosphere of ₂ S ₃ 2 × 10 ^-1 Torr
By vapor deposition to a thickness of μm, a target portion of a photoconductive type image pickup tube having a blocking structure is obtained.

(Embodiment 10) A transparent electrode containing tin oxide as a main component is formed on a glass substrate. Se and Te are deposited on the translucent electrode from separate boats from 1 to 3 μm.
Vacuum deposition to the thickness of. At this time, the Te concentration is 0 wt% at the time of starting the vapor deposition, and is gradually increased as the vapor deposition progresses so that the average concentration of the entire film becomes 0.1 wt%. Sb as an electron injection blocking layer is formed on the photoconductive layer.
₂ S ₃ was added at 0. 2 in an inert gas atmosphere of 2 × 10 ^-1 Torr.
It is vapor-deposited to a thickness of 1 μm to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

(Embodiment 11) A light-transmitting electrode mainly containing indium oxide is formed on a glass substrate. A layer of Se and As or Se and Ge having a film thickness of 0.01 to 1 μm is formed on the translucent electrode by a vacuum evaporation method. For film formation, Se and As ₂ S ₃ or Se and Ge
Are evaporated and vaporized simultaneously from different boats,
The concentration of As or Ge should be 3% by weight on average. Next, Se and Te or Sb, and As or Ge
And a layer having a thickness of 0.01 to 0.06 μm is formed by a vacuum evaporation method. In forming a film, Se, Te or Sb, and As ₂ Se ₃ or Ge are simultaneously evaporated from different boats to be vapor-deposited, and the concentration of Te or Sb is 10 to 15 wt% on average. Make the concentration average 2% by weight. Further, a layer made of Se and As 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, S
e and As ₂ Se ₃ or Se and Ge are simultaneously evaporated from separate boats to be vapor-deposited so that the concentration of As or Ge is 2% by weight on average. 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 0.08 μm to obtain a target portion of a photoconductive type imaging tube having a blocking type structure. .

(Embodiment 12) A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and Se is deposited thereon.
And a layer of As and Ge having a film thickness of 0.5 to 1 μm is formed. When forming a film, Se, As ₂ Se ₃ , and Ge are simultaneously evaporated from different boats and vaporized to form an As film.
And the total concentration of Ge should be 3% by weight on average. This is the first layer. Next, S as the second layer on the first layer
A layer having a film thickness of 0.01 to 0.06 μm, which is composed of e, As, and at least one of Te, Sb, Cd, and Bi, is formed by a vacuum evaporation method. For film formation, Se, As ₂
At least one of Se _3, Te, Sb, Cd, and Bi is vaporized and vaporized simultaneously 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 Te, Sb, C
The total concentration of one or more of d and Bi is 1 on average in the second layer.
It should be 5 to 45% by weight. 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. For film formation, Se
And As ₂ Se ₃ or Ge are vaporized simultaneously from different boats respectively, and the concentration of As or Ge is 2 on average.
Make sure to use the weight percent. Further, Sb ₂ S ₃ as an electron injection blocking layer was vapor-deposited to a thickness of 0.08 μm in an inert gas atmosphere of 2 × 10 ⁻¹ Torr to form a target portion of the photoconductive type imaging tube having the blocking type structure. obtain.

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 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.
An output with a quantum efficiency of 10 or more is obtained at 10 ⁸ V / m.

In Examples 9, 10, 11, and 12, a vacuum deposition film of cerium oxide having a thickness of 0.03 μm, for example, was formed as a rectifying contact auxiliary layer between the transparent electrode and the amorphous semiconductor layer. You can also intervene. 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 containing tin oxide as a main component was formed on a glass substrate, and Se and LiF were evaporated from separate boats on the transparent electrode to 1 to 6 μm. Vacuum deposition to the thickness of. At this time, LiF
Is 500 ppm by weight and is uniformly distributed in the film thickness direction. An Sb ₂ S ₃ layer of 2 × 1 is formed on this layer as an electron injection blocking layer.
Evaporation is performed to a thickness of 0.1 μm 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 14) A light-transmissive electrode mainly composed of indium oxide was formed on a glass substrate, and a film thickness of 0.01 to 0.01 consisting of Se and CaF ₂ was formed on the light-transmissive electrode.
A layer of 0.045 μm is formed by a vacuum evaporation method. When forming a film, Se and CaF ₂ are simultaneously evaporated from different boats and deposited on a substrate so that the concentration of CaF ₂ is 3000 ppm by weight on average. S on it
e is vapor-deposited to a total film thickness of 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 translucent electrode mainly containing tin oxide is formed on a glass substrate. Se is vapor-deposited on the translucent 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. An Se layer is formed thereon by a vacuum vapor deposition method to make the total film thickness 1 to 3 μm. Sb ₂ S ₃ was deposited as an electron injection blocking layer on the Se layer in an inert gas atmosphere of 2 × 10 ⁻¹ Torr to a thickness of 0.1 μm, and the target portion of a photoconductive image pickup tube having a blocking structure was deposited. To get

(Example 16) A translucent electrode mainly composed of indium oxide was formed on a glass substrate, and a film thickness of Se, As and LiF of 0.0 was formed on the translucent electrode.
A layer of 1 to 0.045 μm is formed by a vacuum vapor deposition method.
When forming a film, Se, As ₂ Se ₃ and LiF are simultaneously vaporized from different boats to be vapor-deposited.
The concentration of s is 3 to 6% by weight, and the concentration of LiF is 2000 on average.
˜6000 ppm by weight. S on it
e, film thickness of As and LiF 0.03 to 0.045 μ
The layer of m 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 ppm by weight on average. 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
Up to 3% by weight. On top of that, Sb is used as an electron injection blocking layer.
₂ S ₃ was added at 0. ¹ in an inert gas atmosphere of 1 × 10 ^-1 Torr.
It is vapor-deposited to a thickness of 1 μm to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

(Example 17) A transparent electrode mainly composed of indium oxide was formed on a glass substrate, and S was formed on the transparent electrode.
A layer made of e and LiF and having a film thickness of 0.01 to 0.015 μm is formed by a vacuum vapor deposition method. When forming a film, S
e and LiF are simultaneously vaporized from different boats for vapor deposition, so that the concentration of LiF is 3000 ppm by weight on average. On top of that, a film thickness of Se and LiF of 0.
A layer of 03 to 0.045 μm is formed by a vacuum vapor deposition method. At this time, the concentration of LiF is 8000 to 15000 on average.
Weight ppm. 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. Furthermore, Sb as an electron injection blocking layer is further formed thereon.
₂ S ₃ was added at 0. 2 in an inert gas atmosphere of 2 × 10 ^-1 Torr.
It is vapor-deposited to a thickness of 08 μm to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

Examples 13, 14, 15, 16, 17 described above
The image pickup tube target portion obtained by the above 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 photoconductor layer, and for example, 1.2 × 10 7
An output with a quantum efficiency of 10 or more was obtained at ⁸ V / m. Further, in Examples 13, 14, 15, 16 and 17, a rectified contact auxiliary layer, for example, a cerium oxide vacuum vapor-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 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.

(Embodiment 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 vaporized from separate boats thereon and vacuum-deposited to a thickness of 0.02 to 0.06 μm. At this time, the concentration of SeO ₂ is 2500
It is set to ppm and 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. On top of this, 2 × 10 of Sb ₂ S ₃ was formed as an electron injection blocking layer.
^By vapor deposition to a thickness of 0.1 μm in an inert gas atmosphere of ⁻¹ Torr, a target portion of a photoconductive type image pickup tube having a blocking structure is obtained.

Example 19 A translucent electrode mainly containing tin oxide 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 distributed 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.
Sb ₂ S ₃ was added as an electron injection blocking layer on top of this with 2 × 10 ^-1 T
It vapor-deposits to a thickness of 0.1 μm in an inert gas atmosphere of orr to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

(Embodiment 20) A transparent electrode mainly containing indium oxide is formed on a glass substrate. Thickness made of Se and CaF ₂ on the transparent electrode 0.01 to 0.
A layer of 05 μm is formed by a vacuum evaporation method. When forming a film, Se and CaF ₂ were vaporized simultaneously by vaporization from separate boats, respectively, and the CaF ₂ concentration was 600 on average.
It should be 0 ppm. An amorphous Se layer is formed thereon by a vacuum evaporation method, and then As ₂ Se ₃ is evaporated from a boat and vacuum evaporated to a thickness of 0.03 to 0.06 μm.
Further, Se and GaF ₃ are vaporized from separate boats thereon and vacuum deposited to a thickness of 0.02 to 0.06 μm. At this time, the concentration of GaF ₃ is set to 4000 ppm and is distributed 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. 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 0.08 μm to obtain a target portion of a photoconductive type imaging tube having a blocking type structure. .

(Example 21) A translucent electrode mainly composed of indium oxide was formed on a glass substrate, and a normal thickness of Se, As and LiF of 0.0 was formed on the translucent electrode.
A layer having a thickness of 1 to 0.06 μm is formed by a vacuum evaporation method. When forming a film, Se, As ₂ Se ₃ and LiF are simultaneously evaporated from different boats to be vapor deposited, and As,
The concentration of LiF is 3 to 6% by weight, and the concentration of LiF is 3000 to an average.
It should be 6000 ppm. On top of that, Se, As
And a layer of LiF having a thickness of 0.03 to 0.05 μm are formed by a vacuum evaporation method. At this time, the As concentration is 2-3.5.
The weight% and LiF concentrations are 15000 ppm on average.
Then, Se and As ₂ Se ₃ are simultaneously vapor-deposited from different boats to form an amorphous semiconductor layer having an As concentration of 1 to 3 wt%. 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 700 pp
It is set to m and is uniformly distributed in the film thickness direction. On top of that, Se and A
s ₂ Se ₃ is simultaneously evaporated from different boats and deposited 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 as an electron injection blocking layer is vapor-deposited thereon in an inert gas atmosphere of 1 × 10 ^-1 Torr to a thickness of 0.08 μm to obtain a target portion of a photoconductive image pickup tube having a blocking structure. .

(Embodiment 22) A transparent electrode mainly composed of indium oxide is formed on a glass substrate, and S is formed thereon.
A layer made of e and LiF and having a thickness of 0.03 to 0.06 μm is formed by a vacuum evaporation method. When forming a film, Se and LiF are simultaneously evaporated and vaporized from different boats so that the LiF concentration becomes 4000 ppm on average. On top of that, a film thickness of Se and LiF of 0.03 to 0.0.
A layer of 05 μm is formed by a vacuum evaporation method. L at this time
The concentration of iF 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, T
The e concentration is 5 to 15% by weight. An amorphous Se layer is formed thereon by a vacuum vapor deposition method. On top of that, As ₂ Se ₃ , I
n ₂ O ₃ was evaporated from separate boats and 0.03〜
Vacuum deposit to a thickness of 0.09 μm. At this time, In ₂ O ₃
Has a concentration of 500 ppm and is uniformly distributed in the film thickness direction.
Next, Se and In ₂ O ₃ are evaporated from separate boats and vacuum deposited to a thickness of 0.02 to 0.2 μm. At this time,
The concentration of In ₂ O ₃ is set to 1000 ppm and is distributed 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. Further, Sb ₂ S ₃ as an electron injection blocking layer was vapor-deposited thereon in a thickness of 0.1 μm in an inert gas atmosphere of 2 × 10 ^-1 Torr to form a target portion of a photoconductive type image pickup tube having a blocking type structure. obtain.

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, and for example, 1.2 × 10 ⁸ V / m
When m, an output with a quantum efficiency of 10 or more was obtained.

In addition, Examples 18, 19, 20, 21, and 21
In 2, the vacuum vapor deposition film of cerium oxide having a film thickness of 0.03 μm may be interposed 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 transparent electrode is further improved, it is possible to operate in a higher electric field and further increase the charge multiplication factor.

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

(Example 24) A transparent electrode containing indium oxide as a main component was formed on a glass substrate, and the same photocarrier generation layer as in Example 23 was provided on the transparent electrode. An amorphous semiconductor layer of Se and As or Se and Ge having a film thickness of 0.5 to 6 μm is vacuum-deposited. Sb ₂ S ₃ as an electron-injection blocking layer was formed thereon with 2 × 10 ^-1 Torr.
Vapor deposition to a thickness of 1000Å in an inert gas atmosphere of
A target portion of a photoconductive image pickup tube having a blocking structure is obtained.

The target portion of the image pickup tube obtained in each of Examples 23 and 24 is incorporated into an image pickup tube housing containing an electron gun to obtain a photoconductive type image pickup tube. The obtained image pickup tube is 8 × 1
When operated in an electric field of 0 ^{7 to} 2 × 10 ⁸ V / m, signal amplification occurs in the amorphous semiconductor layer, and for example, 1.2 × 10 ⁸ V / m.
, 1 when all incident light is converted to signal current
An output of 0 times was obtained.

In Examples 23 and 24, a rectifying contact auxiliary layer, for example, a cerium oxide vacuum-evaporated film having a film thickness of 300 Å may be interposed between the transparent electrode and the amorphous semiconductor layer. . 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 composed mainly of indium oxide was formed on a glass substrate, and a thin layer of amorphous silicon nitride containing hydrogen was further formed thereon as a hole injection blocking layer. Accumulate 100 to 1000Å. Next, amorphous silicon containing hydrogen is deposited to 0.5 to 3 μm by glow discharge decomposition of monosilane while the substrate is kept at 200 to 300 ° C. Further thereon, as an intermediate layer, Se containing 20% arsenic is vapor-deposited in an amount of 300Å, and subsequently Se containing 2% arsenic is vacuum-deposited to a thickness of 0.5 to 6 μm. Sb as an electron injection blocking layer on the amorphous Se layer
100 with ₂ S ₃ in an inert gas atmosphere of 2 × 10 ^-1 Torr.
Evaporation is performed to a thickness of 0Å to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

(Example 26) A transparent electrode mainly composed of indium oxide was formed on a glass substrate, and a thin layer of amorphous silicon nitride containing hydrogen was formed thereon as a hole injection blocking layer. ~ 1000Å Accumulate. Next, 200 substrates
While maintaining the temperature at ˜300 ° C., the mixed gas of monosilane and diborane is decomposed by glow discharge to remove boron to 5
Amorphous silicon containing ppm is deposited to 0.5 to 3 μm. Subsequently, as the 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 laminated.
Furthermore, Se containing 2% of arsenic is 0.5 to 6 μm.
Vacuum deposition to the thickness of. 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 1000 Å, and was used as a target of a photoconductive image pickup tube having a blocking type structure. Get the part.

The target portion of the image pickup tube obtained in each of Examples 25 and 26 was 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 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 was 1.2 × 10 ⁸ V / m, a high sensitivity with a gain of about 10 was obtained.

(Example 27) A transparent electrode containing indium oxide as a main component was formed on a transparent substrate, and CdSe as a photocarrier generating layer was formed on the transparent electrode to a film thickness of 0.1. Vacuum deposition is performed to a thickness of 01 to 1 μm. After heat-treating this glass face plate at a temperature of 200 to 400 ° C. in an oxygen atmosphere, 0.5 to 6 μm of amorphous Se is further formed thereon.
Vacuum deposition to the thickness of. Sb ₂ S ₃ was deposited as an electron injection blocking layer on the amorphous Se layer in an inert gas atmosphere of 2 × 10 ^-1 Torr to a thickness of 1000 Å to form a target for a photoconductive image pickup tube having a blocking type structure. Get the part.

(Example 28) A light-transmissive electrode mainly containing indium oxide was formed on a light-transmissive substrate, and the same photocarrier generation layer as in Example 27 was provided on the light-transmissive electrode. An amorphous semiconductor layer made of crystalline 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 as an electron-injection blocking layer was formed thereon with 2 × 10 ^-1 Torr.
Vapor deposition to a thickness of 1000Å in an inert gas atmosphere of
A target portion of a photoconductive image pickup tube having a blocking structure is obtained.

(Example 29) A light-transmissive electrode mainly containing indium oxide was formed on a light-transmissive substrate, and ZnSe having a film thickness of 0.01 as a photocarrier generation layer was further formed on the light-transmissive electrode. .About.0.1 .mu.m, and a ZnCdTe compound of 0.1 .mu.m.
Vacuum deposition is performed to a thickness of 1 to 1 μm. This glass face plate,
After heat treatment at a temperature of 200 to 600 ° C. in an oxygen atmosphere,
Further, amorphous Se is vacuum-deposited thereon to a thickness of 0.5 to 6 μm. Sb ₂ S ₃ as an electron injection blocking layer is formed on the amorphous Se layer in an inert gas atmosphere of 2 × 10 ^-1 Torr.
It is vapor-deposited to a thickness of 000Å to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

(Example 30) A light-transmissive electrode mainly containing indium oxide was formed on a signal light-transmissive substrate, and a layer made of PbS and PbO having a film thickness of 0.1 was formed on the light-transmissive electrode.
Vacuum deposition is performed to a thickness of 01 to 1 μm. Further, amorphous Se is vacuum-deposited thereon to a thickness of 0.5 to 6 μm.

Sb ₂ S ₃ was used as an electron injection blocking layer on the amorphous Se layer in an inert gas atmosphere of 2 × 10 ^-1 Torr.
It is vapor-deposited to a thickness of 000Å to obtain a target portion of a photoconductive type image pickup tube having a blocking structure.

(Example 31) A light-transmissive electrode made of a light-transmissive metal thin film was formed on a signal light-transmissive substrate, and HgCdTe was formed as a photocarrier generation layer on the light-transmissive electrode.
The compound is deposited to a film thickness of 0.01 to 0.1 μm. Further, amorphous Se is vacuum-deposited thereon to a thickness of 0.5 to 6 μm. Sb ₂ S ₃ as an electron injection blocking layer on the amorphous Se layer
1000 Å 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.

Examples 27, 28, 29, 30 and 31
The image pickup tube target portion obtained by the above 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 subjected to an electric field of 8 × 10 ⁷ to 2 × 1 applied to the charge multiplication layer.
When a voltage is applied to operate at 0 ⁸ V / m, signal amplification occurs in the charge multiplication layer made of an amorphous semiconductor,
For example, when the electric field applied to the charge multiplication layer is 1.2 × 10 ⁸ V / m, 10
Double output was obtained.

(Example 32) A glass substrate having a transparent electrode mainly composed of indium oxide provided on the surface thereof was placed in a sputtering apparatus, and a SiO ₂ thin film as a hole injection blocking layer was formed on this transparent electrode. 100-1000Å is deposited.
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 reduced to 0. Deposit 5 to 3 μm. Further, amorphous Se is vacuum-deposited thereon to a thickness of 0.5 to 6 μm. 2x Sb ₂ S ₃ as an electron injection blocking layer on the amorphous Se layer
The target portion of the photoconductive type image pickup tube having the blocking type structure is obtained by vapor deposition to a thickness of 1000 Å in an inert gas atmosphere of 10 ^-1 Torr.

(Example 33) A light-transmitting electrode mainly composed of indium oxide was formed on a glass substrate, and a photocarrier generating layer made of the same amorphous silicon as that of Example 32 was provided on the transparent electrode. Amorphous Se and As, or Se on top
And an amorphous semiconductor layer made of Ge and having a thickness of 0.5 to 6 μm is vacuum-deposited. On top of that, Sb ₂ S _{3 is formed} as an electron injection blocking layer.
1000 Å 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.

The target portion of the image pickup tube obtained in each of Examples 32 and 33 was incorporated into an image pickup tube housing containing an electron gun.
Obtain a photoconductive 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 was 1.2 × 10 ⁸ V / m, a high sensitivity with a gain of about 10 was obtained.

(Example 34) A transparent electrode containing tin oxide as a main component was formed on a glass substrate, and further, GeO ₂ of 200 Å and CeO ₂ of 200 Å were formed in a thickness of 3 × 10 as a rectifying contact auxiliary layer. -Deposit in a vacuum of ^-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 the As concentration is uniformly distributed in the film thickness direction. The amorphous semiconductor layer is deposited 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.
Evaporation is performed to a thickness of 800 Å in an argon atmosphere of × 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 8 × 10 ⁷ V / m to 2 × 10 ⁸ V / m which causes a charge multiplication effect.

(Example 35) A light-transmitting electrode mainly containing indium oxide is formed on a glass substrate. CeO ₂ as a rectifying contact auxiliary layer of 300 Å is formed on the transparent electrode.
To a thickness of 3 × 10 ⁻⁶ Torr in vacuum. Se is deposited thereon as an amorphous semiconductor layer to a thickness of 2 μm and 2 × 10 ^−6.
Deposition in a Torr vacuum. 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 action of 8 × 1.
It is operated in an electric field of 0 ⁷ V / m to 2 × 10 ⁸ V / m.

(Example 36) A transparent electrode containing indium oxide as a main component was formed on a glass substrate, and GeO ₂ was added as 200 Å and CeO ₂ as 200 as a rectifying contact auxiliary layer.
Evaporate to a thickness of Å. This vapor deposition is performed in a vacuum of 2 × 10 ^-6 Torr. Subsequently, an amorphous semiconductor layer is deposited. For the amorphous semiconductor layer, Se and As ₂ Se ₃ are first vapor-deposited to a thickness of 300 Å from separate vapor deposition boats. In this case, the As concentration is 3% by weight, and the As concentration is uniformly distributed in the film thickness direction. Then S
e, As ₂ Se ₃ , and LiF are vapor-deposited to a 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 so that the LiF concentration is evenly distributed in the film thickness direction. On top of that, Se, A
s ₂ Se ₃ is vapor-deposited to a thickness of 1.4 μm in a separate vapor deposition boat. In this case, 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. 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 the amorphous semiconductor layer thereof is subjected to a charge multiplication action of 7 × 1.
It is operated in an electric field of 0 ⁷ V / m to 2 × 10 ⁸ V / m.

(Example 37) A transparent electrode mainly composed of indium oxide was formed on a glass substrate, and further CeO ₂ was formed as a rectifying contact auxiliary layer in a thickness of 300 × 3 × 10 3.
-Deposit in a vacuum of ^-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 the As concentration is uniformly distributed in the film thickness direction. Subsequently, Se, As ₂ Se ₃ , and In ₂ O ₃ were added from separate vapor deposition boats in an amount of 1
Evaporate to a thickness of 000Å. At this time, the As concentration is 3% by weight and In ₂ O ₃ is 500 ppm by weight, and the As concentration 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. On the amorphous semiconductor layer, Sb ₂ S ₃ was used as an electron injection blocking layer in an argon atmosphere of 3 × 10 ^-1 Torr for 900 times.
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 thereof has a charge multiplication effect of 7 × 10 ⁷ V / m to 2 × 10 ⁸ V / m.
It is operated in an electric field of m.

(Example 38) A transparent electrode containing tin oxide as a main component was formed on a glass substrate, and further, GeO ₂ of 200 Å and CeO ₂ of 200 Å were formed in a thickness of 3 × 10 as a rectifying contact auxiliary layer. -Deposit in a vacuum of ^-6 Torr. An amorphous semiconductor layer is vapor-deposited thereon. First, the amorphous semiconductor layer is Se and A.
s ₂ Se ₃ is vapor-deposited to a thickness of 300 Å using separate vapor deposition boats. At this time, the As concentration is 6% by weight, and the As concentration is uniformly distributed in the film thickness direction. Then Se, As ₂ S
e ₃ and LiF are 600 by separate vapor deposition boats.
Evaporate to a thickness of Å. In this case, the As concentration is 2 by weight.
%, And the LiF concentration is 4000 ppm in weight ratio, and is uniformly distributed in the film thickness direction. Next, Se and As ₂ Se ₃ are vapor-deposited to a thickness of 1.5 μm from separate vapor deposition boats. In this case, the As concentration is 2% by weight, and the As concentration is uniformly distributed in the film thickness direction. Se, As ₂ Se ₃ , and In ₂ O ₃ are vapor-deposited on them by separate vapor deposition boats to a thickness of 2000 Å. 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. Further, Se and As ₂ Se ₃ are vapor-deposited on them by separate vapor deposition boats to a thickness of 2000 Å. In this case, 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 3 × 10 ⁻⁶ Torr. 2 × 1 of Sb ₂ S ₃ as an electron injection blocking layer is formed on the amorphous semiconductor layer.
Evaporate to a thickness of 1000Å in an argon atmosphere of 0 ^-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 7 × 10 ⁷ V / m to 2 × 10 ⁸ V / m which causes a charge multiplication effect.

(Example 39) A light-transmitting electrode mainly composed of indium oxide was formed on a glass substrate, and further CeO ₂ was formed as a rectifying contact auxiliary layer in a thickness of 200 × 3 × 10 3.
-Deposit in a vacuum of ^-6 Torr. An amorphous semiconductor layer is vapor-deposited thereon. For the amorphous semiconductor layer, first, Se and As ₂ Se ₃ are vapor-deposited from separate vapor deposition boats to a thickness of 5000 Å. At this time, the As concentration is 3% by weight, and the As concentration is uniformly distributed in the film thickness direction. Subsequently, Se and As ₂ Se ₃ are vapor-deposited in a thickness of 300 Å from separate vapor deposition boats. In this case, the As concentration is 20% by weight, and the As concentration is uniformly distributed in the film thickness direction. Next, Se and As ₂ Se ₃ are vapor-deposited in a thickness of 5000 Å from separate vapor deposition boats. In this case, the As concentration is 3% by weight, and the As concentration is uniformly distributed in the film thickness direction. On top of that, Se, As ₂
Se ₃ is vapor-deposited from separate vapor deposition boats to a thickness of 300Å. At this time, the As concentration is 20% by weight, and the As concentration is uniformly distributed in the film thickness direction. Further, Se and As ₂ Se ₃ are vapor-deposited thereon from separate vapor deposition boats to a thickness of 5000Å. In this case, the As concentration is 10% 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 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 vapor-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 the amorphous semiconductor layer thereof is subjected to a charge multiplication action of 5 × 1.
It is operated in an electric field of 0 ⁷ V / m to 2 × 10 ⁸ V / m.

(Example 40) A transparent electrode containing tin oxide as a main component was formed on a glass substrate, and further, GeO ₂ of 150 Å and CeO ₂ of 150 Å were formed in a thickness of 2 × 10 as a rectifying contact auxiliary layer. -Deposit in a vacuum of ^-6 Torr. An amorphous semiconductor layer is vapor-deposited thereon. First, the amorphous semiconductor layer is Se, A
s ₂ Se ₃ is vapor-deposited from separate vapor deposition boats to a thickness of 600Å. At this time, the As concentration is 3% by weight, and the As concentration 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. As in this case
The concentration is 10% by weight, and the concentration is evenly distributed in the film thickness direction. Then _{Se, Te, As 2 Se 3} , by respective separate vapor deposition boat, LiF is deposited to a thickness of 900 Å. In this case, the Te concentration is 15% by weight, the As concentration is 2% by weight, and the LiF concentration is 4000 ppm by weight, which are uniformly distributed in the film thickness direction. On top of that, Se, As ₂ Se ₃ , I
n ₂ O ₃ is vapor-deposited in a thickness of 150 Å by separate vapor deposition boats. At this time, the As concentration is 25% by weight, I
The n ₂ O ₃ concentration is set to 500 ppm in weight ratio and is uniformly distributed in the film thickness direction. Further, Se and As ₂ Se ₃ are vapor-deposited thereon from separate vapor deposition boats to a thickness of 1.8 μm. In this case, 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. Next, 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 1000 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 /
It is operated in an electric field of m to 2 × 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 formed as a rectifying contact auxiliary layer in a thickness of 200 × 3 × 10 ⁻⁶ T.
Evaporate in orr vacuum. An amorphous semiconductor layer is vapor-deposited thereon. For the amorphous semiconductor layer, Se and As ₂ Se ₃ are first vapor-deposited to a thickness of 2000 Å from separate vapor deposition boats. At this time, the As concentration is 3% by weight, and the As concentration 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. In this case, the As concentration is 1% by weight and the LiF concentration is 20% by weight.
It is set to 00 ppm and is uniformly distributed in the film thickness direction. Then S
e, As ₂ Se ₃ , and Te are vapor-deposited in a thickness of 1 μm from separate vapor deposition boats. In this case, the As concentration is 1% by weight, and the As concentration is uniformly distributed 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. Subsequently, Se and As ₂ Se ₃ are vapor-deposited to a thickness of 150 Å by separate vapor deposition boats. In this case, the As concentration is 20% by weight, and the As concentration is uniformly distributed in the film thickness direction. Then, Se and As ₂ Se ₃ are vapor-deposited to a thickness of 2500Å from separate vapor deposition boats. 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 amorphous semiconductor layer is 2
Performed in a vacuum of × 10 ^-6 Torr. On the amorphous semiconductor layer, Sb ₂ S ₃ is deposited 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 thereof is subjected to a charge multiplication action of 6 × 1.
It is operated in an electric field of 0 ⁷ V / m to 2 × 10 ⁸ V / m.

(Example 42) A transparent electrode composed mainly of tin oxide was formed on a glass substrate, and a hydrogenated amorphous silicon nitride film was formed as a 200 Å film by a glow discharge method as a rectifying contact auxiliary layer. It is formed thick. A hydrogenated amorphous silicon film is formed to a thickness of 2000 liters by a glow discharge method. Se and As ₂ Se ₃ are vapor-deposited thereon by separate vapor deposition boats to a thickness of 150Å. In this case, the As concentration is 30% by weight, and the As concentration is uniformly distributed in the film thickness direction. Further, Se and As ₂ Se ₃ are vapor-deposited thereon by separate vapor deposition boats to a thickness of 1.8 μm. At this time, the As concentration is 2% by weight, and the As concentration is uniformly distributed in the film thickness direction. The deposition of Se and As ₂ Se _{3 on} the amorphous semiconductor layer is performed in a vacuum of 3 × 10 ^-6 Torr. Subsequently, an electron injection blocking layer is deposited. For the electron injection blocking layer, Sb ₂ S ₃ is deposited to a thickness of 1000 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 6 × 10 ⁷ V / m.
It operates in an electric field of up to 2 × 10 ⁸ V / m.

(Example 43) A transparent electrode containing tin oxide as a main component is formed on a glass substrate. Next, an amorphous semiconductor layer is deposited. For the amorphous semiconductor layer, first, Se is 1000 Å
Evaporated to a thickness of. Then, Se and LiF are vapor-deposited from separate vapor deposition boats to a thickness of 1000 Å. The LiF concentration at this time is 3000 ppm by weight, and the LiF concentration 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.
For the electron injection blocking layer, Sb ₂ S ₃ is deposited to a thickness of 1000 Å 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 7 × 10 ⁷
It is operated in an electric field of V / m to 2 × 10 ⁸ V / m.

[0132]

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 characteristics.

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

[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 a principle configuration of a target portion of an image pickup tube according to the present invention.

FIG. 3 is a diagram showing characteristics of a target portion of an image pickup tube according to the present invention.

FIG. 4 is a diagram showing characteristics of a target portion of an image pickup tube according to the present invention.

FIG. 5 is a diagram showing characteristics of a target portion of the image pickup tube according to the present invention.

FIG. 6 is a diagram showing characteristics of a target portion of an image pickup tube according to the present invention.

FIG. 7 is a diagram showing characteristics of a target portion of an image pickup tube according to the present invention.

FIG. 8 is a diagram showing an example of a principle configuration of a target portion of an image pickup tube according to the present invention.

FIG. 9 is a diagram showing an example of a principle configuration of a target portion of an image pickup tube according to the present invention.

FIG. 10 is a diagram showing a basic configuration of a camera configured using the image pickup tube according to the present invention.

[Explanation of symbols]

1, 21, 81, 91 ... Translucent substrate, 2, 22, 82,
92, ... Translucent electrode, 3 ... Photoconductive film, 24, 84, 94
... Amorphous semiconductor layer, 86, 96 ... Photo carrier generation layer, 9
7 ... Middle layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuro Kawamura 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Junichi Yamazaki 1-10-11 Kinuta, Setagaya-ku, Tokyo Issue Japan Broadcasting Corporation Broadcasting Technology Research Institute (72) Inventor ▲ Day Eku Eku 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting System Broadcasting Technology Research Institute (72) Inventor Kazuhisa Taketoshi Setagaya-ku, Tokyo Kinuta 1-1011, Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Shiro Suzuki 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Takashi Yamashita Tokyo 1-10-11 Kinuta, Setagaya-ku, Japan Broadcasting Corporation Broadcasting Technology Research Institute (72) Inventor Mitsuo Kosugi 1-10-11 Kinuta, Setagaya-ku, Tokyo Broadcasting Association of Japan Research Institute (72) Inventor Kizumi Ikeda 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcast Technology Laboratory (72) Inventor Masaaki Aiba 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Association Broadcast Technology Laboratory (72) Inventor Tadaaki Hirai 1-280 Higashi Koikeku, Kokubunji City, Tokyo Hitachi, Ltd. Central Research Laboratory (72) Inventor Yukio Takasaki 1-280 Higashi Koikeku, Kokubunji, Tokyo Hitachi Ltd. Inside the Central Research Laboratory (72) Inventor Yoshio Ishioka 1-280 Higashi Koikekubo, Kokubunji, Tokyo Inside Hitachi Central Research Center (72) Inventor Tatsuo Makishima 1-280 Higashi Koikeku Ku, Tokyo Kokubunji City Inside Hitachi Research Center Co., Ltd. ( 72) Inventor Kenji Samejima 1-280 Higashi Koikekubo, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Inventor Takeshi Uda 1-280 Higashi Koikeku, Kokubunji, Tokyo Hitachi Research Laboratory (72) Inventor Naohiro Goto 3300 Hayano, Mobara-shi, Chiba Hitachi Mobara Plant, Inc. (72) Inventor Ikumi Nonaka 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Mobara Plant (72) Inoue Eigen 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Mobara factory

Claims (28)

[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 emitting an electron beam for scanning the target portion. An electron beam control unit for accelerating, deflecting, and focusing, wherein the photoconductive film has a blocking contact, and the photoconductive film absorbs incident light to generate light. It comprises a photocarrier generation layer for generating most of the carriers, and a charge multiplication layer for multiplying the generated photocarriers, which is composed of an amorphous semiconductor layer having at least a part of charge multiplication ability. An image pickup tube characterized by the above. 2. The image pickup tube according to claim 1, wherein the amorphous semiconductor layer is made of an amorphous semiconductor mainly containing Se. 3. The image pickup tube according to claim 2, wherein the film thickness of the amorphous semiconductor layer is 0.5 μm or more and 10 μm or less. 4. The image pickup tube according to claim 2 or 3, wherein the amorphous semiconductor layer contains one or both of As and Ge. 5. The image pickup tube according to claim 2, 3 or 4, wherein the amorphous semiconductor layer is selected from Te, Sb, Cd and Bi in at least a part of its thickness direction. An image pickup tube characterized by containing at least one person. 6. The image pickup tube according to claim 5, wherein the region is provided in the amorphous semiconductor layer away from the transparent electrode. 7. The image pickup tube according to claim 5 or 6, wherein Te, Sb, Cd, Bi contained in the region.
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. 8. The image pickup tube according to claim 2, 3, 4, 5, 6 or 7, wherein the amorphous semiconductor layer forms a hole trap level in at least part of its thickness direction. An image pickup tube comprising a substance that 9. The image pickup tube according to claim 8, wherein the substance forming the hole trap level is Li, Na, K, Mg, C.
a, Ba, Tl and their fluorides, and Al, C
An imaging tube characterized by being at least one selected from the group consisting of fluorides of r, Mn, Co, Pb, and Ce. 10. The image pickup tube according to claim 8 or 9, wherein the substance that forms the hole trap level is contained in a part of the amorphous semiconductor layer on the light incident side. Camera tube. 11. The image pickup tube according to claim 8, 9 or 10, wherein a local concentration of the substance forming the hole trap level in the amorphous semiconductor layer is 20 p.
An image pickup tube characterized by being pm or more and 10% by weight or less. 12. The image pickup tube according to claim 2, wherein the amorphous semiconductor layer contains a substance that forms an electron trap level in at least part of its thickness direction. An image pickup tube characterized by the above. 13. The image pickup tube according to claim 12, wherein the substance forming the electron trap level is copper oxide, indium oxide, selenium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, gallium fluoride, indium fluoride,
An image pickup tube characterized by being at least one member selected from the group consisting of Zn, Ga, In, Cl, I and Br. 14. The image pickup tube according to claim 12, wherein the substance that forms the electron trap level is contained in a part of the amorphous semiconductor layer near the electron beam scanning side. An image pickup tube. 15. The image pickup tube according to claim 12, 13 or 14, wherein the local concentration of the substance forming the electron trap level in the amorphous semiconductor layer is 20 ppm by weight or more and 10% by weight or more. An image pickup tube characterized by the following. 16. The image pickup tube according to claim 1, wherein the photocarrier generation layer is provided on the light incident side of the photoconductive film with respect to the charge multiplication layer. 17. The image pickup tube according to claim 1 or 16, wherein the photoconductive film is between the photocarrier generation layer and the charge multiplication layer and has an intermediate band gap or spatial electric field strength. An image pickup tube having a layer. 18. The image pickup tube according to claim 17, wherein the intermediate layer has a material containing a first other substance in an amorphous body mainly containing Se. 19. The image pickup tube according to claim 18, wherein the first other substance is bismuth, cadmium, and chalcogenides thereof, tellurium, tin, arsenic, germanium, antimony, indium, gallium, and chalcogens thereof. Compound, sulfur, chlorine, iodine, bromine, copper oxide, indium oxide, selenium oxide, vanadium pentoxide,
An image pickup tube characterized by being at least one of molybdenum oxide, tungsten oxide, gallium fluoride, and indium fluoride. 20. The image pickup tube according to claim 17, wherein the intermediate layer contains at least a material containing a second other substance in an amorphous body mainly containing Si. 21. The image pickup tube according to claim 20, wherein the second other substance is a first group element made of germanium, carbon, nitrogen and tin, or a second group element made of group III and group V elements. An image pickup tube characterized by being at least one of them. 22. The image pickup tube according to claim 1, wherein the photocarrier generation layer is Zn, C.
Mainly composed of a first material which is a combination of at least one element of the third group consisting of d, Hg and Pb and at least one element of the fourth group consisting of O, S, Se and Te. An image pickup tube characterized by the above. 23. The image pickup tube according to claim 22, wherein the first material is ZnS, CdS, ZnSe, CdSe, Z.
An image pickup tube characterized by being at least one of nTe, CdTe, HgCdTe, PbO, and PbS. 24. The image pickup tube according to claim 1, wherein the photocarrier generation layer is mainly composed of a tetrahedral amorphous material containing halogen or hydrogen. tube. 25. The image pickup tube according to claim 24, wherein the halogen is at least one of fluorine and chlorine. 26. The image pickup tube according to claim 1, wherein the photocarrier generation layer is amorphous S.
An image pickup tube comprising a material mainly containing i. 27. A photoconductive film having a photocarrier generation layer that absorbs incident light to generate most of the photocarriers, and a charge multiplication layer that multiplies the generated photocarriers, and has a blocking type. A method of operating an image pickup tube having a structured target portion, wherein the charge multiplication layer comprises an amorphous semiconductor layer having a charge multiplication ability, and the photoconductive film is formed inside the amorphous semiconductor layer. A method of operating an image pickup tube, which is operated in an electric field region that exhibits a charge multiplying ability. 28. The method of operating an image pickup tube according to claim 27, wherein the amorphous semiconductor layer is made of a material containing Se as a main component, and the electric field region is 5 × 10 ⁷ V / m to 2 × 1.
A method of operating an image pickup tube, which is in the range of 0 ⁸ V / m.