Patent ID: 7199447

Claim:
A transistor formed in a semiconductor substrate, the substrate including a surface and a region doped with an impurity which promotes one of either holes or electrons as a first majority carrier, the transistor comprising: a collector region having an impurity therein which promotes the other of holes or electrons as a second majority carrier, the collector region extending from the surface of the substrate; a base region having an impurity therein which promotes the first majority carrier, the base region comprising an intrinsic base region and a surrounding extrinsic base region, the intrinsic base region extending from the surface of the substrate into contact with a portion of the collector region; an emitter region on the base region, the emitter region having a surface area smaller than a surface area of the intrinsic base region; a first implant region interposed between the collector region and the base region, the implant region having an increased doping of an implant impurity and having an effective surface area grater than the surface area of the emitter region contiguous to the base region and less than the area of the intrinsic base region contiguous to the collector region; and a second implant region formed in the collector region.