GB896316A - Improvements in or relating to semi-conductor devices - Google Patents

Abstract

896,316. Transistors. SIEMENS & HALSKE A. G. June 10, 1960 [June 12, 1959], No. 20462/60. Addition to 886,561. Class 37. A method of producing a semi-conductor device includes the steps of alloying a piece of significant impurity metal to a body of semiconductor material, thereafter maintaining that part of the metal outside the alloy zone in a molten state at a temperature lower than that required for alloying, removing a large proportion of the said molten metal by means of suction, and attaching a member of good heat conductivity to that surface from which the molten metal has been removed. Thus the metal body of good heat conductivity may have an aperture and be connected to the remaining metal by the method described in the parent Specification. Fig. 2 shows a plate 1 of ntype germanium having an annular base contact 2, and indium emitter and collector electrodes 3, 4, alloyed to the plate 1 at about 500‹ C. The device is subjected to streams of nitrogen at about 250‹ C., and the molten indium forming the collector electrode is sucked away via a glass pipe 7. A small piece of solder, e.g. 60/40 Sn/Pb with flux core, is then melted on the collector area and a disc-shaped contact member 9, Fig. 3, of good heat conductivity material, e.g. copper, is placed on the solder layer and thereby attached to the alloy zone, in an atmosphere of nitrogen. The disc 9 may then be soldered to a larger plate of good heat conductivity. The suction step may take place in a reducing atmosphere.