Patent ID: 7037798

Claim:
A method for fabricating a bipolar transistor with a raised extrinsic base, an emitter and a collector, the method comprising the steps of: a) providing a structure including an intrinsic base, an emitter cap and an intrinsic base layer adjacent the intrinsic base, a first insulator layer on the emitter cap, a raised extrinsic base layer over the first insulator layer, and a second insulator layer over the raised extrinsic base layer; b) forming an emitter opening by selectively removing portions of the raised extrinsic base layer and the second insulator layer to expose the first insulator layer; c) forming a first spacer along a sidewall of the emitter opening; d) selectively removing the first insulator layer inside the emitter opening only; e) forming a third insulator layer in a lower portion of the emitter opening; f) selectively removing the first insulator layer to form an undercut under the raised extrinsic base layer; g) forming a conductive link layer in the emitter opening that fills the undercut; h) selectively removing the conductive link layer to the third insulator layer within the emitter opening; and i) forming the emitter.