| 摘要 |
1,249,714. Image pick-up tubes; semiconductor targets. WESTERN ELECTRIC CO. Inc. 22 July, 1969 [26 July, 1968], No. 36720/69. Headings H1D and H1K. [Also in Division C7] In a method of making a target structure for an image pick-up tube, the structure comprising a semi-conductive substrate 20 of one conductivity type having adjacent one surface thereof an array of charge storage regions 21 which are preferably of opposite conductivity type, and a layer 22 of insulating material covering the surface except for at least part of the regions and adapted to shield the surface from a scanning electron beam; an array of conductive metal deposits 23 are formed on the regions 21 by electroless or electrolytic deposition. The deposits 23 may extend outwardly of the surface of the layer 22 thereby partly shielding the layer and increasing the beam landing area, or may alternatively be flush with the surface. The regions 21 may be partly etched out before the metal areas 23 are deposited so that these areas are anchored within the substrate and the space charge regions are brought closer to the bottom of the target and the resolution is improved (Fig. 3, not shown). In one example a silicon target having a 10 ohm-cm. N-type base region and a hexagonal array of diodes formed by boron diffused regions 8 microns in circumference on 15 micron centres defined by a SiO 2 insulating film is cleaned in HF and immersed in a gold cyanide bath. The bath consists of 21.3 g./l. KAu(CN) 2 and 50 g./l. (NH 4 ) 2 HC 6 H 5 O 7 at 65‹ C. and the target is cathodic with a current density of 4 ma./cm.<SP>2</SP> of exposed silicon. After plating for one hour a gold layer 6-8 microns thick covers each diode region. Alternative metals for electroplating are nickel, cobalt, palladium, platinum or the platinum group, silver, or copper; for electroless deposition the metals nickel, cobalt and platinum are suitable. A minimum thickness of 300 Š is adequate. The storage areas need not be PN junctions but may be M1S diodes or rectifying barriers constituted by metal-semiconductor contacts as in Schottkybarrier devices. |
