Patent ID: 7368765

Claim:
A bipolar transistor comprising: a plurality of semiconductor layers comprising a collector layer, a base layer in contact with the collector layer, and an emitter layer in contact with the base layer, the base layer having the opposite doping type of the collector layer and the emitter layer, wherein the plurality of semiconductor layers are formed to comprise: an intrinsic base region adjacent to and in contact with the emitter layer and an extrinsic base region, the extrinsic base region being adapted to make contact with a base electrode and extending laterally from the intrinsic base region; a sub-collector region connected to a main collector region, located laterally from the main collector region, and adapted to make contact with a collector electrode, the sub-collector region being doped heavier than the collector layer; and an emitter formed by the emitter layer, wherein a region of the collector layer adjacent to the extrinsic base region is selectively type converted to have the same doping type as the base layer, wherein the emitter is surrounded in part by a plurality of portions of the sub-collector region and in part by a plurality of portions of the extrinsic base region, and wherein the plurality of portions of the sub-collector region and the plurality of portions of the extrinsic base region are alternatively arranged around the emitter.