GB694041A - Electric signal translating devices utilizing semiconductive bodies - Google Patents

Abstract

694,041. Semi-conductor amplifiers. WESTERN ELECTRIC CO., Inc. June 6, 1950 [June 9, 1949], No. 14082/50. Class 40 (iv). [Also in Group XL (b)] An electric signal translating device of the transistor type comprises a semi-conductor body having a grain boundary or thin layer of one conductivity type between two zones of opposite conductivity type, and connections to each of the two zones and to the layer or boundary. Semi-conductor material of predetermined conductivity type may be prepared as described in Specifications 632,942, [Group XL (b)], and 632,980, [Group XL (c)], which relate to germanium or as in Specifications 592,260, 592,303, [both in Group XL], or 669,399, [Group XL (b)], which relate to silicon, and it has been found that crystal boundaries consisting of a thin layer of one conductivity type between two zones of opposite conductivity type may exist in bodies of such material.' These boundaries may be located by microscopic examination, or by passing a lights spot along the surface and observing reversals in the direction of photo current measured between opposite end regions of the body. Fig. 4 shows a semi-conductor block 10 of N-type material having a thin layer 19 of conductivity type which extends to and is in electrical contact with the base electrode 13. Emitter and collector electrodes 11 and 12 are positioned on opposite sides of the layer, and are spaced 2 or 3 mils apart. If two closely adjacent layers 19 exist in the body both extending through to the base electrode 13, the central portion may be connected to one emitter or collector electrode, while the outer zones may be connected to two collector or emitter electrodes. The invention results in reduced base impedance in the transistor circuit, and avoids the resulting feed-back which may be undesirable in certain amplifiers. Specification 694,021 also is referred to.