Patent ID: 7049240

Claim:
A formation method of SiGe HBT, comprising: providing a semiconductor structure, which has a p-type epi-silicon surface and first polysilicon surface; forming a base layer upon said p-type epi-silicon surface and said first polysilicon surface; forming a first emitter layer upon said base layer; forming a first dielectric layer upon said first emitter layer; forming a spacer structure upon a side wall of said first emitter layer and said first dielectric layer, wherein said base layer is covered partially by said spacer structure; covering a second polysilicon layer upon said base layer, wherein said second polysilicon layer is next to said spacer structure and contact with partially; forming a second dielectric layer upon said second polysilicon layer; planarizing said second dielectric layer until said first dielectric layer and said spacer structure are exposed partially; removing said first dielectric layer in order to expose said first emitter layer; and forming a second emitter layer upon said first emitter layer.