GB1052857A - - Google Patents

Abstract

1,052,857. Semi-conductor devices. STANDARD TELEPHONES & CABLES Ltd. Oct. 15, 1965, No. 43819/65. Heading H1K. In an integrated circuit comprising a plurality of spaced devices formed in a single slice of semi-conductor material, the material between the devices is treated to produce regions with a carrier recombination rate sufficient to provide electrical isolation. The isolating regions may be produced in a silicon slice by diffusing in gold to reduce the carrier lifetime. In an embodiment, Fig. 1 (not shown), an array of photo-voltaic diodes is produced by diffusing phosphorus into a P-type silicon wafer 11 to produce an N-type layer 12, masking using a photo-lithographic technique and etching to produce mesas each containing a junction 13. Gold is plated or evaporated using a mask on to the surface of the regions between the mesas and diffused in to form isolating regions 14. Individual contacts 15a and a common contact 15b are applied to the mesas and the opposite face of the wafer respectively. In a modification, Fig. 2 (not shown), junctions 26 are produced by the planar process using a thermally grown oxide mask, the etching step is omitted, and the gold is diffused into regions 26 between the devices. The gold diffusion may be performed by photo-masking the oxide layer and etching to expose the surface on which gold is vapour deposited or plated using an electroless method before diffusing-in. Alternatively gold may be vapour deposited through a mask on to the surface of the oxide layer and then diffused through the oxide into the body.