Patent ID: 7803685

Claim:
A method for forming a semiconductor device, comprising: providing a semiconductor substrate; forming emitter, base and collector regions in or on the substrate; providing an extrinsic base contact region ohmically coupled to the base region; forming an emitter contact region ohmically coupled to the emitter region, wherein a portion of the emitter contact region overhangs a portion of the extrinsic base contact region; forming a cavity of predetermined lateral depth and vertical height between the overhanging portion of the emitter contact region and the underlying portion of the extrinsic base contact region; and exposing the emitter contact region and the extrinsic base contact region to metal atoms so as to form a first conductive semiconductor-metal alloy on an upper surface of the emitter contact region, and a second conductive semiconductor-metal alloy on an upper surface of the extrinsic base contact region wherein the second conductive semiconductor-metal alloy extends into the cavity under the overhanging portion of the emitter contact region.