| 摘要 |
749,392. Semi-conductor devices. RADIO CORPORATION OF AMERICA. Sept. 24, 1953 [Oct. 22, 1952; Oct. 23, 1952], No. 26378/53. Class 37. A semi-conductor device having alloy junction emitter and collector electrodes comprises a large cooling member connected to the collector electrode to dissipate heat from the collector junction. Fig. 1 shows a junction transistor comprising a germanium wafer 2, and indium-germanium alloy portions 4 and 5 with PN junctions 15 and 16. A wire 10 and a copper cooling member 8 are electrically and thermally connected to the indium portions, by means of a saturated or nearly saturated solution of indium in mercury which is applied by wetting one or both surfaces. Tin chloride may be used as a flux. If the temperature of the device is raised after application, and then cooled, the solution becomes supersaturated and solidifies. The transistor is coated with coil dope 13 and a paint layer 14, and potted in synthetic resin 17. The solution may comprise other metals in place of indium. Aluminium, gallium and zinc are also specified as acceptor impurities. In Fig. 2, which also shows a junction transistor, the indium-germanium alloy portions are connected to copper radiating plates 122, 128, by a bonding material 124 consisting of indium or other acceptor material, or by a low-melting point solder. Copper plate 130 provides the base connection, and the surface regions are coated with a layer 135 of polystyrene. In a modification, the plates 122, 128 are provided with an apertured depressed central portion, and a drop of bonding material is dropped through the hole to bond the indium alloy portion to the plate. Cooling fins may be provided on plates 122 and 128. The base electrode plate 130 may be attached to a heat transmitting insulating sheet on a chassis. Silicon may be used in place of germanium. |
