EP0114652B1 - Cible de tube de prise de vues - Google Patents

Cible de tube de prise de vues Download PDF

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Publication number
EP0114652B1
EP0114652B1 EP19840100470 EP84100470A EP0114652B1 EP 0114652 B1 EP0114652 B1 EP 0114652B1 EP 19840100470 EP19840100470 EP 19840100470 EP 84100470 A EP84100470 A EP 84100470A EP 0114652 B1 EP0114652 B1 EP 0114652B1
Authority
EP
European Patent Office
Prior art keywords
layer
amorphous semiconductor
image pickup
pickup tube
tube target
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19840100470
Other languages
German (de)
English (en)
Other versions
EP0114652A3 (en
EP0114652A2 (fr
Inventor
Eisuke Inoue
Yasuhiko Nonaka
Masanao Yamamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Publication of EP0114652A2 publication Critical patent/EP0114652A2/fr
Publication of EP0114652A3 publication Critical patent/EP0114652A3/en
Application granted granted Critical
Publication of EP0114652B1 publication Critical patent/EP0114652B1/fr
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/39—Charge-storage screens
    • H01J29/45—Charge-storage screens exhibiting internal electric effects caused by electromagnetic radiation, e.g. photoconductive screen, photodielectric screen, photovoltaic screen
    • H01J29/451—Charge-storage screens exhibiting internal electric effects caused by electromagnetic radiation, e.g. photoconductive screen, photodielectric screen, photovoltaic screen with photosensitive junctions
    • H01J29/456—Charge-storage screens exhibiting internal electric effects caused by electromagnetic radiation, e.g. photoconductive screen, photodielectric screen, photovoltaic screen with photosensitive junctions exhibiting no discontinuities, e.g. consisting of uniform layers

Definitions

  • the present invention relates to an image pick up tube target and, more particularly, to a structure of a Se-As-Te type chalcogen photoconductive film (Saticon (trade mark) film) with improved sticking characteristics.
  • Fig. 1 shows a section of a main part of a conventional image pickup tube target and a concentration distribution of selenium, arsenic and tellurium as major constituents of a photoconductive film.
  • a transparent conductive film 2 containing Sn0 2 or ln 2 0 3 as a major constituent is formed on the rear major surface of a disc-like glass substrate 1.
  • a very thin N-type transparent Ce0 2 conductive film 3 serving as a blocking layer is formed on the rear major surface of the transparent conductive film 2.
  • a P-type photoconductive film 4 comprising a P-type Se-As-Te amorphous semiconductor film is formed on the rear major surface of the N-type transparent conductive film 3.
  • a P-type Sb 2 S 3 photoconductive film 5 serving as a beam landing layer is formed on the rear major surface of the P-type photoconductive film 4.
  • the P-type photoconductive film 4 consists of first, second and third P-type photoconductive layers 4a, 4b and 4c.
  • the first P-type photoconductive layer 4a comprises a P-type Se-As amorphous semiconductor film having an Se concentration of 97 to 98 wt% and an As concentration of 3 to 12 wt% and is formed on the rear major surface of the N-type transparent conductive film 3 to have a thickness of 30 to 60 nm.
  • the second P-type photoconductive layer 4b comprises a P-type Se-As-Te amorphous semiconductor film having an Se concentration of about 67 wt%, an As concentration of 3 wt%, and a Te concentration of about 30 wt% and is formed on the rear major surface of the first P-type photoconductive layer 4a to have a thickness of about 60 nm.
  • the third P-type photoconductive layer 4c is formed on the rear major surface of the second P-type photoconductive layer 4b such that a total thickness of the multilayer film 4 is set to be about 3900 nm, for example.
  • the third P-type photoconductive layer 4c comprises a P-type Se-As amorphous semiconductor film wherein in the Se-As concentration distribution, the As concentration continuously changes from 20 to 30 wt% to 3 ⁇ 2 wt% over a thickness of 45 ⁇ 20 nm which starts from the interface between the second and third P-type photoconductive layers 4b and 4c.
  • the 3 ⁇ 2 wt% As concentration remains unchanged as the thickness increases.
  • the P-type photoconductive film 5 is formed on the rear major surface of the multilayer film 4.
  • a light beam 6 is incident on the front major surface of the glass substrate 1, and a scanning electron beam 7 is supplied to the P-type photoconductive film 5.
  • the gradient As concentration layer as part of the third P-type photoconductive layer 4c serves as a carrier extraction layer for effectively and stably extracting carriers generated in the Te layer of the second P-type photoconductive film 4b.
  • the gradient As concentration layer also serves to prevent the Te layer from being diffused, thereby preventing degradation of the voltage-photocurrent characteristic (V-I characteristic) forming part of evaluation criterion.
  • the uniform 3 ⁇ 2 wt% As concentration layer contiguous to the gradient As concentration layer serves as a capacitive layer for storage of the carriers.
  • the P-type photoconductive layer 4c including the gradient As concentration layer and the uniform As concentration layer is the most important layer to determine quality of the electrical characteristics of the target in use.
  • the sticking phenomenon largely depends on the content of highly concentrated arsenic in the third P-type photoconductive layer 4c. With the content of arsenic decreased, the sticking can be suppressed but sufficient extraction of the carriers from the Te layer cannot be sustained. As a result, a practically sufficient signal current cannot be obtained.
  • EP-A-0 067 015 describes an image pickup tube target in which the multilayer photoconductive film has a first amorphous semiconductor layer mainly made of Se and As, a second amorphous semiconductor layer mainly made of Se, Te and As, a third amorphous semiconductor layer mainly made of Se, As and on the fourth layer side doped with In 2 0 3 , and a fourth amorphous semiconductor layer mainly made of Se and As with an average concentration of As being lower than that in the third layer. So a layer doped with a dopant (in 2 O 3 ) having negative space charges in selenium is formed as a sublayer of the third amorphous semiconductor layer in contact with the fourth amorphous semiconductor layer and not in contact with the second amorphous semiconductor layer.
  • a dopant in 2 O 3
  • an object of the present invention to provide an image pickup tube target capable of suppressing the sticking phenomenon by optimizing the doped layer position and compensating for a decrease in carrier extraction effect due to a decrease in arsenic content of the high arsenic concentration layer.
  • an image pickup tube target comprising: a transparent substrate; a first transparent conductive film formed on a rear major surface of said transparent substrate; a second transparent conductive film serving as a blocking layer and formed on a rear major surface of said first transparent conductive film; a multilayer photoconductive film which has a first amorphous semiconductor layer mainly made of Se and As, a second amorphous semiconductor layer mainly made of Se, Te, and As, a third amorphous semiconductor layer mainly made of Se and As, and a fourth amorphous semiconductor layer mainly made of Se and As with an average concentration of As being lower than that in the third layer, in the order named, including a sublayer doped with a dopant having negative space charges in selenium in contact with the fourth amorphous semiconductor layer and not in contact with the second amorphous semiconductor layer, which multilayer photoconductive film is formed on a rear major surface of said second transparent conductive film to have a predetermined thickness; and a single
  • Fig. 2 shows a section of a main part of an image pickup tube target according to an embodiment of the present invention, and a diagram of a Se-As-Te concentration distribution.
  • Figs. 1 and 2 the same reference numerals are used to denote the same parts, a detailed description of which will be omitted.
  • a third P-type photoconductive layer 4d as a carrier extraction layer is formed on the rear major surface of a second P-type photoconductive layer 4b as a carrier generating layer to have a thickness of 12 ⁇ 6 nm.
  • the layer 4d comprises a P-type Se-As amorphous semiconductor film having a concentration distribution such that the Se concentration is 75 ⁇ 5 wt% and the As concentration is 25 ⁇ 5 wt%.
  • a fourth P-type photoconductive layer 4e serving as a capacitive layer is formed on the rear major surface of the third P-type photoconductive layer 4d to have a thickness such that a multilayer film 4' has a total thickness of, for example, about 3900 nm.
  • the fourth P-type photoconductive layer 4e comprises a P-type Se-As amorphous semiconductor film having a concentration such that the Se concentration is 97 ⁇ 2 wt% and the As concentration is 3 ⁇ 2 wt%.
  • In 2 0 3 having negative space charges in selenium is doped to a thickness of 3 to 30 nm at a concentration of 100 to 3,000 wtppm across an interface between the third and fourth P-type photoconductive layers 4d and 4e, so that an In 2 0 3 -doped layer 4f is formed not to contact the Te layer of the second P-type photoconductive layer 4b.
  • the layer 4f is illustrated as doped with ln 2 0 3 , other dopants such as Mo0 2 or a mixture of In 2 0 3 and Mo0 2 which have negative space charges in selenium may also be used.
  • the arsenic content (concentrationxthickness) in the third P-type photoconductive layer 4d as the carrier extraction layer is decreased to 1/3 to 1/6 of that of the conventional image pickup tube target.
  • the doped layer 4f of In z 0 3 , Mo0 2 or mixture thereof which has negative space charges in selenium and which has carrier extraction capability is formed across the interface between the third and fourth P-type photoconductive layers 4d and 4e, so that the carrier extraction efficiency is greatly improved and the sticking phenomenon can be greatly decreased.
  • the arsenic content of the carrier extraction layer is decreased to about 1/6 or lower, the effect for preventing tellurium from being diffused from the second P-type photoconductive layer 4b is impaired. Therefore, the arsenic content in a rectangular concentration distribution cannot be decreased to about 1/6 or lower.
  • Fig. 3 shows the relation between the position of the indium-doped layer 4f and the sticking contrast for various In 2 0 3 doping contents (wtppm . nm) as defined by concentration y (wtppm)xthickness x (nm).
  • Curves 1 to 4 correspond to doping contents of 90000 wtppm - nm (3000 wtppmx30 nm), 15000 wtppm . nm (1000 wtppmx15 nm), 8000 wtppm ⁇ nm (750 wtppmx12 nm) and 300 wtppm - nm (100 wtppmx3 nm), respectively.
  • Points P1, P2 and P3 correspond to positions of the indium-doped layer as shown in Figs. 4a, 4b and 4c, respectively. It will then be appreciated that when the indium-doped layer is formed across the interface X, preferably, substantially centered to the interface X, all the characteristic curves 1 to 4 representative of 100 to 3000 wtppm ln 2 0 3 doping concentrations and 3 to 30 nm indium-doped layer thicknesses fall in an allowable sticking contrast range as hatched.
  • the ln 2 0 3 layer is formed in a thickness region having as a center the interface or boundary X where the arsenic content (25 ⁇ 5 wt%) of the third P-type photoconductive layer 4d is abruptly decreased to the arsenic content (3 ⁇ 2 wt%) of the fourth P-type photoconductive layer 4e.
  • the arsenic content gradually decreases as shown at solid line or dotted line in Fig. 5.
  • the In 2 0 3 layer may be formed in a thickness region having as a center a point where the arsenic concentration of the third P-type photoconductive layer 4d is decreased to 10% of an arsenic concentration difference between the third and fourth P-type photoconductive layers 4d and 4e.
  • the total thickness of P-type photoconductive layer 4' is not limited to 3900 nm and the effects of the present invention can be attained irrespective of the total thickness.
  • the total thickness may be 5900 nm with the photoconductive layer 5 ending at 6000 nm.
  • Mo0 2 or a mixture thereof is doped in a highlight sticking prevention Saticon Film (Japanese Patent Application No. 55-157084) doped with Li-F across an interface between the first and second P-type photoconductive layers 4a and 4b as shown at dotted line in Fig. 2, to form a doped layer 4f.
  • a highlight sticking prevention Saticon Film Japanese Patent Application No. 55-157084
  • Li-F across an interface between the first and second P-type photoconductive layers 4a and 4b as shown at dotted line in Fig. 2
  • the sticking phenomenon can be prevented in the same manner as in the above embodiment.
  • the sticking phenomenon which results from picking up of a highly luminous object can also be suppressed.
  • the sticking phenomenon due to highly luminous incident light can be greatly decreased to obtain a high-quality image.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)

Claims (7)

1. Cible pour tube capteur d'images comprenant:
un substrat transparent (1);
un premier film conducteur transparent (2) formé sur une surface majeure arrière dudit substrat transparent (1);
un second film conducteur transparent (3) servant de couche de blocage et formé sur une surface majeure arrière dudit premier film conducteur transparent (2);
un film photoconducteur multicouche (4') qui a une première couche semi-conductrice amorphe (4a) principalement faite de Se et As, une seconde couche semi-conductrice amorphe (4b) principalement faite de Se, Te et As, une troisième couche semi-conductrice amorphe (4d) principalement faite de Se et As, et une quatrième couche semi-conductrice amorphe (4e) principalement faite de Se et As avec une concentration moyenne de As plus faible que celle de la troisième couche (4d), dans l'ordre nommé, comprenant une sous-couche (4f) dopée d'un dopant ayant des charges spatiales négatives dans le sélénium en contact avec la quatrième couche semi-conductrice amorphe (4e) et non en contact avec la seconde couche semi-conductrice amorphe (4b), lequel film photoconducteur multicouche (4') est formé sur une surface majeure arrière dudit second film conducteur transparent (3) pour avoir une épaisseur prédéterminée; et
un seul film photoconducteur (5) formé sur une surface majeure arrière de ladite quatrième couche semi-conductrice amorphe (4e) dudit film photoconducteur multicouche (4'), caractérisée en ce que
ladite sous-couche (4f) est formée à travers l'interface entre lesdites troisième et quatrième couches semi-conductrices amorphes (4d, 4e) dudit film photoconducteur multicouche (4') et en ce que ladite interface est définie en tant que limite où la concentration en arsenic est dimi- nuèe d'environ 90% de la différence de concentration en arsenic entre lesdites troisième et quatrième couches semi-conductrices amorphes (4d, 4e).
2. Cible pour tube capteur d'images selon la revendication 1, où le dopant est Inz03.
3. Cible pour tube capteur d'images selon la revendication 1, où la dopant est Mo02.
4. Cible pour tube capteur d'images selon la revendication 1, où le dopant est un mélange de ln203 et Mo02.
5. Cible pour tube capteur d'images selon l'une des revendications 1 à 4, où ladite sous-couche dopée (4f) est centrée sur ladite interface.
6. Cible pour tube capteur d'images selon l'une quelconque des revendications 1 à 5, où ladite sous-couche dopée est formée de manière que le l'oxyde d'indium soit dopé à une concentration de 100 à 3000 ppm en poids sur une épaisseur comprise entre 3 et 30 nm.
7. Cible pour tube capteur d'images selon l'une quelconque des revendications 1 à 6, comprenant de plus une sous-couche de Li-F formée à travers une interface entre lesdites première et seconde couches semi-conductrices amorphes.
EP19840100470 1983-01-19 1984-01-18 Cible de tube de prise de vues Expired EP0114652B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP591583A JPS59132541A (ja) 1983-01-19 1983-01-19 撮像管タ−ゲツト
JP5915/83 1983-01-19

Publications (3)

Publication Number Publication Date
EP0114652A2 EP0114652A2 (fr) 1984-08-01
EP0114652A3 EP0114652A3 (en) 1984-08-08
EP0114652B1 true EP0114652B1 (fr) 1987-09-09

Family

ID=11624188

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840100470 Expired EP0114652B1 (fr) 1983-01-19 1984-01-18 Cible de tube de prise de vues

Country Status (3)

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EP (1) EP0114652B1 (fr)
JP (1) JPS59132541A (fr)
DE (1) DE3466130D1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0648616B2 (ja) * 1984-05-21 1994-06-22 株式会社日立製作所 光導電膜
JPS61193337A (ja) * 1985-02-20 1986-08-27 Hitachi Ltd 撮像管タ−ゲツト
JPS61193335A (ja) * 1985-02-20 1986-08-27 Hitachi Ltd 撮像管タ−ゲツト
JPS63299035A (ja) * 1987-05-29 1988-12-06 Sony Corp 非晶質セレンを主体とする光導電膜

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5832454B2 (ja) * 1979-06-07 1983-07-13 日本放送協会 光導電性タ−ゲツト
JPS57197876A (en) * 1981-05-29 1982-12-04 Nippon Hoso Kyokai <Nhk> Photoconductive film

Also Published As

Publication number Publication date
EP0114652A3 (en) 1984-08-08
JPS59132541A (ja) 1984-07-30
EP0114652A2 (fr) 1984-08-01
JPH0522328B2 (fr) 1993-03-29
DE3466130D1 (en) 1987-10-15

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