Semiconductor electric signal translating devices and methods of making them

摘要

759,012. Heat-treating semi-conductor material; coating by vapour deposition. WESTERN ELECTRIC CO., Inc. Sept. 14, 1951 [Sept. 14, 1950; Sept. 14, 1950], No. 21634/51. Classes 72 and 82(2). [Also in Group XXXVI] A signal translating device comprises a metallic electrode which is embedded in, or bonded to a germanium or silicon body, and the region of the body in the vicinity of the electrode has its significant impurity content modified. In one example, an electric current is passed through an unpointed gold wire 25 applied to the surface of an N-type germanium wafer 22 until the germanium fuses. The gold alloys with the germanium and Fig. 2 shows the resulting physical bond; a thin region P is converted to P-type conductivity by diffusion of the gold. The arrangement provides an improvised rectifying contact. The wire may be pressed into the fused body so that it is embedded in the germanium. Two adjoining electrodes of this type may be provided to form a transistor. Various embodiments are described. The electrode may include a significant impurity which is introduced into the semi-conductor body either during the embedding or bonding operation or by subsequent heat treatment. Alternatively, conductivity inversion or modification may be carried out by thermal treatment during, or after, bonding without introduction of impurity. Heating may be effected by passing current through the electrode or by an electric arc, and may be carried out in vacuo-inert gas or air. The electrode can also consist of an iron-nickel alloy, platinum, tantalum, or tungsten. Coating of the electrode with acceptor or donor material may be effected by heating a wire in a vapour, of for example antimony or phosphorus. It improves transistor properties if the emitter used on N-type material and/or the collector used on P-type material comprise a major portion of acceptor material and a minor portion of donor material so that the structure finally has an NPN formation. The conductivity types and acceptors and donors may be interchanged to achieve the same result. Silicon or germanium may be used as semiconductor material. Copper is included as an example of an acceptor impurity. Specifications 632,942, 632,980, 694,021, 700,231, 700,232 [Group XXXVI], and 721,671 are referred to.