GB997184A - Improvements in or relating to methods of manufacturing semiconductor devices - Google Patents

Abstract

997,184. Semi-conductor devices. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. April 6, 1962 [April 10, 1961], No. 13346/62. Drawings to Specification Heading H1K. In a method of manufacturing a semiconductor device such as a thermoelectric assembly or a temperature-sensitive resistor, a metal part having at least its contact surface of copper, silver, or of an alloy of copper and/or silver is brought into contact with a semiconductor mass of bismuth telluride, or with a mass of mixed crystal material containing bismuth telluride, at a temperature lower than the melting temperature of the contact surface of the metal part but sufficiently high that at least the part of the semi-conductor mass adjacent the contact surface becomes liquid and reacts with the metal part to form on cooling a mechanical and electrical connection between the part and the body formed by the mass In the semi-conductor material bismuth may be partly replaced by antimony, and tellurium by sulphur and/or selenium. The metal part may consist wholly of one of the above mentioned materials or those materials may be present as a surface layer (produced for example electrolytically, or by rolling) on bodies consisting of materials such as ion, aluminium, or aluminium alloys The method may be carried out in an inert or reducing atmosphere and additionally or alternatively oxide-dissolving fluxes such as borax or acid sodium ammonium phosphate may be applied to the contact surfaces. To join the metal part to the mass either the mass is cast in a mould in contact with the part so that connection is established simultaneously with the casting operation, or the heated metal part is held against a preformed semi-conductor body so that a thin layer of the latter adjacent the contact surface melts, after which the assembly is cooled. In the particular embodiments a heated strip of copper or of a copper-nickel-zinc alloy is coated with a borax flux and held against adjacent preformed bismuth telluride elements which are separated by a mica spacer. An N-type element consists of 80% wt. bismuth telluride and 20% wt. bismuth selenide, and a P-type element consists of 40% wt. of bismuth telluride and 60% wt. antimony telluride. A plurality of pre-formed elements may be connected simultaneously by placing them in a jig together with the necessary metal parts, and then heating the latter by placing one or more heated structures against them.