Improvements in and relating to broad area transistors

Abstract

Abstract 738,216. Semiconductor devices. GENERAL ELECTRIC CO. June 15, 1953 [June 14, 1952], No. 16403/53. Class 37. A broad area transistor comprising a monocrystalline wafer of N-type germanium 1 (Fig. 1), having emitter and collector dot electrodes 4, 5 of acceptor impurities on opposite sides is characterized in that the final thickness of N-type germanium 11 between the electrodes is small by comparison with the diameter of the electrodes, the ratio being one-tenth to one-hundredth. The P-N junctions between the electrodes and the wafer are produced by the controlled time/heat treatment of Specification 728,129. A base electrode 8, e.g. of fernico, is soldered to the germanium wafer preferably using a solder 10 including a donor impurity, and wire terminals 6, 7 are added to the collector and emitter electrodes 4, 5, during the heat treatment. To facilitate cooling at the emitter and collector, sheet metal cups 12 (Fig. 3) may be soldered to each impurity dot 4, 5, which may be other than spherical. In another embodiment (Figs. 6, 7) a large area collector electrode is provided by impurity 16, with a plurality of elongated emitter electrodes 18 on the opposite face of the germanium 17, the base electrode comprising conducting elements 19 joined by a conductor 20, and soldered to the germanium. The collector electrode 16 may be water cooled or have cooling fins attached. The base metal may alternatively be a P-type semiconductor with emitter and collector electrodes of donor impurity. Specification 728,304 also is referred to.

Inventors

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