Self aligned poly emitter bipolar technology using damascene technique

摘要

A polysilicon emitter of a bipolar device is formed utilizing a self- aligned Damascene technique. An oxide mask is patterned over epitaxial silicon implanted to form the intrinsic base. The oxide mask is then etched to form a window. Polysilicon is uniformly deposited over the oxide mask and into the window. The polysilicon is then polished to remove polysilicon outside of the window. Etching of the oxide mask follows, with good selectivity of oxide over silicon. This selectivity produces a polysilicon emitter atop an intrinsic base, the base flush with the silicon surface rather than recessed because of overetching associated with conventional processes.