| 摘要 |
847,524. PN junction rectifiers. GENERAL ELECTRIC CO. Ltd. March 13, 1958 [March 15, 1957], No. 81714/57. Class 37. A rectifier assembly comprises a PN junction rectifier formed by alloying an activator metal mass to a semiconductor body, mounted within an envelope made of two metal parts sealed together. The rectifier is mounted on one of the parts and a connecting member the crosssectional area of which is nowhere less than 5 % of the PN junction area extends through but is insulated from said part to make contact with the metal mass. In the manufacture of one embodiment (Fig. 4) superposed discs 37, 36, 35, 34 of N type germanium, solder, iron-nickelcobalt alloy and solder respectively are clamped by a split cylinder 42 between two halves of a graphite mould 38 on an offset boss 29 extending from the base of a flanged copper cup 28. The end of a J-shaped copper connector sealed through a glass bead in the base of the cup is disposed adjacent to the germanium disc. The assembly is mounted on a trolley 6 (Fig. 1) in an elongated quartz chamber 1 provided with heating coil 3 and cooling duct 4 which at equilibrium produce a temperature which gradually increases from 300 ‹C. at one end of the chamber to 500 ‹C. at the centre and then falls rapidly in the cooled region. The trolley is gradually moved to the centre of the chamber where its presence photoelectrically actuates a dispenser 14 to discharge a metered amount of molten indium at 400 ‹C. into the mould 38. The indium dissolves some of the germanium and when the assembly passes into the cooled end of the chamber the germanium recrystallises to form a PN junction, the residual indium solidifies to bond connector 32 to the germanium body and the solder to bond the germanium to boss 29 via disc 35. After removal of the assembly from the chamber and dismantling of the mould the enlarged flange of a second flanged copper cup otherwise externally similar to cup 27 is cold welded in dry nitrogen to the flange of cup 27 to form a sealed casing for the device. The device may be air cooled or, if the boss is formed with a water passage by flow of fluid therethrough. Specifications 787,389, 817,362, 831,085 and 831,086 are referred to. |
