Self-aligned collector implant for bipolar transistors.

摘要

An improved method of forming bipolar devices and an improved bipolar device. The method provides for formation of an emitter contact on the base of a bipolar transistor followed by a collector implant. The collector implant varies the doping profile of the collector under the emitter contact but not adjacent the emitter contact, providing improved device characteristics. The collector implant penetrates the base of the transistor, preferably having a range deeper than the thickness of the single-poly contact layer.