Self-aligned epitaxial base transistor and method for fabricating same.

摘要

A self-aligned epitaxial base transistor comprising: a semiconductor substrate having shallow and deep trench isolation regions (18, 14, 16) defining a collector region (11, 12) doped with a first conductivity type, an intrinsic base layer (22) of epitaxial semiconductor doped with a second conductivity type formed on said substrate, a thin very heavily doped layer (24) of semiconductor formed on said intrinsic base layer (22), said thin heavily doped layer being heavily doped with said second conductivity type, an extrinsic base layer (26) of polycrystalline semiconductor formed on said thin very heavily doped layer (24), said extrinsic base layer being doped with said second conductivity type; at least one layer (30, 32) of an insulating material formed on said extrinsic base layer (26), an emitter region (46) of polycrystalline semiconductor formed in an opening (34) in said at least one layer (30, 32) of insulating material, said extrinsic base layer (26) and said thin layer (24) of very heavily doped polycrystalline semiconductor, said emitter region (46) contacting said intrinsic base layer (22) through said opening (34).