Heterojunction bipolar transistor having a germanium extrinsic base utilizing a sacrificial emitter post

摘要

Disclosed is a method for fabricating a heterojunction bipolar transistor (“HBT”), and the resulting structure. The method includes forming a germanium layer over a SiGe layer, the SiGe layer including an intrinsic base. Thereafter, an emitter sacrificial post and a raised germanium extrinsic base are formed by etching away portions of the germanium layer. Then, a conformal dielectric layer is deposited over the raised germanium extrinsic base. The process continues by removing the emitter sacrificial post and forming an emitter over the intrinsic base within an emitter opening defined by the previous removal of the emitter sacrificial post. The resulting structure has a raised germanium extrinsic base with a reduced parasitic base-collector capacitance.

主权项

1. A method for fabricating a heterojunction bipolar transistor (“HBT”) comprising:
forming a germanium layer over a SiGe layer, said SiGe layer including an intrinsic base; forming an emitter sacrificial post and a raised germanium extrinsic base by etching away portions of said germanium layer, said emitter sacrificial post in direct contact with said SiGe layer; depositing a conformal dielectric layer over said raised germanium extrinsic base; removing said emitter sacrificial post; forming an emitter over said intrinsic base within an emitter opening defined by said removing said emitter sacrificial post.