GB1289651A - - Google Patents

Abstract

1289651 Image pick-up tubes; semi-conductor arrays TOKYO SHIBAURA ELECTRIC CO Ltd 20 Jan 1970 2721/70 Headings H1D and H1K The target of an image pick-up tube comprises an array of junctions on a semi-conductor layer supported by a monocrystalline insulating transparent substrate. In Fig. 3 a mono crystalline layer 11 of N-type silicon 20 microns thick is formed on a sapphire substrate 10 and covered with an insulating layer 12 of silicon dioxide formed with an array of apertures through which P-type material is diffused to form regions 13 in which N-type regions 16 are formed. A gold coating 15 is deposited round the periphery to form an electrode. In a modification, Fig. 1 (not shown), the regions 16 are omitted and in a modification of this diode arrangement (Fig. 2, not shown) the regions 13 extend right through to the substrate. The N-P-N arrangement shown in Fig. 3 may also be modified by extending the regions 13 and 16 right through to the substrate (Fig. 4, not shown). In another arrangement, Fig. 5F, the sapphire substrate has its upper and lower surfaces selected to be the (0001) faces and a nickel layer 21 of 0.5 micron thickness is formed on the substrate and etched to provide a pattern of apertures 10 microns diameter at a pitch of 15 microns. N-type monocrystalline silicon 3 microns thick is deposited at 22a over the substrate whilst the deposits at 22b over the nickel are polycrystalline. An apertured silicon oxide layer 23 covers the surface and boron is diffused through the apertures to form P-type regions 26 to a depth of 0.5 micron. The layer 21 may be of silicon oxide or chromium oxide or may be omitted. In a modification, Fig. 6 (not shown), islands of silicon are formed on the substrate and surrounded by metal or semiconductor, after which the apertured insulating layer is formed and P-type material diffused through the apertures. In a further arrangement, Fig. 7, metal islands 33 are deposited in the apertures in the insulating layer 32 to form Schottky junctions and are coated with a second metal at 35; the first metal may be gold, platinum, tungsten, nickel, molybdenum, titanium or aluminium and the second metal gold, titanium or tungsten. The substrate may be of spinel, quartz, magnesia or calcium fluoride instead of sapphire and may include an impurity to give selective transmission of light; cobalt improves violet transmission, chromium green, and copper infra-red. The semi-conductor material may be gallium arsenide or phosphide instead of silicon.