GB891934A - Improvements in or relating to semi-conductor devices - Google Patents

Abstract

891,934. Transistors. STANDARD TELEPHONES & CABLES Ltd. Aug. 7, 1959 [Aug. 14, 1958], No. 26120/58. Class 37. In a junction transistor, one of three lead wires, which pass through an electrically insulating member and are connected in low resistance contact to the electrodes of the transistor, has a cross-sectional area substantially greater than that of the other two lead wires, and a heat conductive container enclosing the device is in thermal contact with said member. As shown, Figs. 8 and 9, a transistor comprises a crystal element 61 of e.g. Ge, having alloyed emitter and collector electrodes 64, 65, of e.g. In, and an ohmic base electrode 63 comprising a metal ring and a free extending portion. The electrodes are connected to lead wires 2, 3, 4 which may be of a Cu-coated Ni-Fe alloy or Cu, plated with e.g. Au, and which are sealed through a body 1 of electrically insulating material such as glass or ceramic, the lead wire 3, which is connected to the collector electrode 65, having a substantially greater cross-sectional area than the wires 2, 4, along its whole length or that part of its length which extends from the collector electrode to, or through, the body 1. For instance, wire 3 may have a diameter of 0.040 inch as against a diameter of 0.018 inch for wires 2, 4. The lead wire 2, which may be of either configuration shown or may comprise a single right-angle bend at the level of the emitter electrode 64, is sufficiently resilient to hold the crystal and electrode assembly in position relative to the lead-wires during manufacture. In the embodiment shown in Fig. 10, the lead wire 4 has the greater crosssectional area and.is connected to a base electrode 66 comprising a conductive plate having a central hole (not shown) through which the collector (or, in a modification, the emitter) electrode protrudes. In alternative embodiments, the wire 2, or the wires 2, 3 may be connected to their respective electrodes by means of an intermediate lead wire. The transistor is protected by a cylindrical cover 131, Fig. 14, a flange 132 of which seats on a flange 43 of a metal ferrule surrounding the glass or ceramic body, a skirt 42 of the ferrule being collapsed radially inwards over the flange 132 and the visible joint being soldered at 141. In an alternative embodiment, the ferrule comprises an annular lip in place of the flange 43, on to which lip the cylindrical cover seats. When the latter is metallic, the mating surfaces of cover and ferrule are tinned before engagement, and the visible joint between them is soldered; when the container is non-metallic, the solder is replaced by a hard-setting synthetic resin. Specifications 801,442 and 801,444 are referred to.