Bildumsetzer

摘要

1,241,379. Image pick-up tubes; semiconductor target. WESTERN ELECTRIC CO. Inc. 21 May,1969 [27 May, 1968], No. 25936/69. Headings H1D and H1K. A target electrode for a vidicon-type tube comprises a substrate 10 adapted to produce hole-electron pairs on exposure to radiation, and a plurality of charge-storage regions 12 separated by insulating material 11, the materials of areas 11 and 12 being such that the quotient of the thickness and the dielectric constant is greater for areas 11 than for areas 12. The substrate may be N-type silicon 5 to 30 microns thick for use with visible light, gallium arsenide for infra-red, or gold for use with X-rays. The regions 12 are preferably of a material wherein the current is proportional to a power of the voltage, such as silicon nitride, boron nitride, Al 2 O 3 , Ta 2 O 5 or SiO x , where x is less than 2, and may be 500 Š thick; the areas 11 may be of silicon nitride or silicon dioxide 5000 Š thick. The two materials need not be different or entirely separate. In one modification, Fig. 3 (not shown), holes corresponding to areas 12 are formed in a continuous insulating layer on the substrate, and a second insulating material is then deposited over the entire surface of the target. In another modification, Fig. 4 (not shown), two insulating layers are deposited over the entire surface of the target, and holes are formed in the outer layer to expose areas of the inner layer. A thin phosphorus n+ layer may be diffused into the surface of the target exposed to the image to provide ohmic contact, low surface recombination velocity for holes, and impurity gettering to increase bulk lifetime. The surface of the isolating insulator 11 can be covered with a metal or semi-insulating film to dissipate unwanted charge accumulation.