Pre-poly emitter implant

摘要

A process of forming an emitter of a bipolar transistor is described. Dopants of a first conductivity type is implanted in the substrate to form the base. Dopants of a second conductivity type is then implanted into the base region to form a substrate emitter region. A polysilicon layer is then deposited over the substrate emitter and doped to form the doped polysilicon layer. An outdiffusion step follows to link the doped polysilicon layer to the substrate emitter.