Patent ID: 6876060

Claim:
A semiconductor device comprising: a vertical NPN bipolar transistor and a vertical PNP bipolar transistor each having a collector layer, a base layer, and an emitter layer formed on a common silicon substrate, wherein each of said vertical NPN bipolar transistor and said vertical PNP bipolar transistor comprises a first epitaxial layer formed on the surface of said silicon substrate, an isolation insulating film disposed on the surface of said first epitaxial layer, a first portion of said collector layer formed on the surface of said first epitaxial layer and surrounded by said isolation insulating film, and a second epitaxial layer extending on said first epitaxial layer and said isolation insulating film; and wherein said second epitaxial layer comprises a silicon layer as a second portion of said collector layer, a silicon germanium layer as said base layer, and a silicon layer as said emitter layer in the order from the bottom.