GB878100A - Improvements in or relating to semi-conductor rectifiers of the p-n junction type - Google Patents

Abstract

878,100. Semi-conductor rectifying devices. SIEMENS-SCHUCKERTWERKE A.G. July 31, 1958 [July 31, 1957; July 23, 1958], No. 24738/58. Class 37. The silicon or germanium element of a junction rectifier is disposed on the base of a cupshaped portion of a metal holder and the second terminal connecting member of the rectifier is a rigid pin which is mounted on the electrode of the semi-conductor element and is connected at its surrounding surface to the holder by welded connections through an insulated bushing. Fig. 1 shows frusto-conical holder member 1 of copper with a cup-shaped recess to the bottom of which a molybdenum plate 4 has been fixed, a ring 2 of weldable material such as iron or nickel is fitted to the lip 1a of the cup-shaped portion. An aluminium plate 5 is laid on the molybdenum; a silicon semi-conductor element 6 is laid on the aluminium and this in turn is covered with an electrode body 7 for example of gold-antimony. A tungsten plate 8 is then placed on the electrode and a rigid pin 9 having good thermal conductivity is then mounted at its lower face on the tungsten electrode. The PN junction is then formed by heating and etching. A separate ring 13 consisting of weldable material is mounted on a shoulder on the outer face of the pin and the pin is hollow in order that it may eventually be used for evacuating the space around the semi-conductor device. The insulating member 14, consists of a glass ring and an inner metal ring 15 and an outer metal ring 16 shaped so that they may engage rings 13 and 2 respectively to which they are welded by a process of resistance welding known as " hump welding. The conical member 1 engages a larger member 17 and is wedged in place by a threaded plug 18. A stud 19 on member 1 facilitates withdrawal. A cap 11 is applied after evacuation. Pin 9 may engage cooling fins and may form part of a plug coupling, Figs. 3-7 (not shown).