Patent ID: 7875908

Claim:
A bipolar transistor, comprising: a P-type collector in a silicon substrate; an intrinsic base on said collector, said intrinsic base including a first N-type dopant species, germanium and carbon; an N-type extrinsic base over a first region and a second region of said intrinsic base, said first region over said collector and said second region over a dielectric adjacent to said collector, said N-type extrinsic base including a second N-type dopant species; a P-type emitter on said first region of said intrinsic base; and said intrinsic base includes: a first intrinsic silicon layer on said collector; a first silicon-germanium (SiGe) layer on said first intrinsic silicon layer, said first SiGe layer doped with carbon; an N-type doped SiGe layer on said first SiGe layer, said N-type doped SiGe layer doped with said N-type dopant species and carbon; a second SiGe layer on said first intrinsic silicon layer, said second SiGe layer doped with carbon; and a second intrinsic silicon layer on said second SiGe layer.