Patent ID: 7473610
Filing Date: 2009-01-06
Classification: H01L

Abstract:
1. A method of forming a heterojunction bipolar transistor (HBT) device, the method comprising: forming an intrinsic base layer over a collector layer; forming a sacrificial block structure over the intrinsic base layer; forming a sacrificial spacer layer surrounding top and side surfaces of the sacrificial block structure; forming an extrinsic base layer over the intrinsic base layer and adjacent the sacrificial spacer layer; forming a protective layer over the extrinsic base layer; removing the sacrificial spacer layer and implanting a ring shaped dopant profile within an upper portion of the collector layer, wherein the ring shaped collector implant structure corresponds to a pattern of the removed sacrificial spacer layer; removing the sacrificial block structure so as to expose an emitter opening; forming sidewall spacers within the emitter opening; and forming an emitter within the emitter opening, wherein the ring shaped dopant profile is disposed so as to be aligned beneath a perimeter portion of the emitter.