Power transistor having good thermal fatigue capabilities

Claim 1

A transistor comprising: a. a wafer of semiconducting material including emitter, base and collector regions; b. said emitter region being of one conductivity type and being disposed adjacent a surface of said wafer, said emitter region being composed of a plurality of separate portions each of which comprises a trunk with pairs of lateral branches extending from a central area of said surface and said branches being of progressively increasing length toward the periphery of said surface; c. a bonding pad at the periphery of each said trunk; d. a base region of opposite conductivity type also adjacent said wafer surface, said base portion including said central surface area and having branches interdigitated with said emitter region branches; e. an emitter contact electrode comprising a metal plate suspended above said wafer surface, said plate being connected only to each of said bonding pads, said plate having a central aperture, and; f. a base contact electrode extending through said aperture connected to said central area base region portion.