A nonrecessed-base, self-aligned bipolar structure with selectively deposited polysilicon emitter

A self-aligned bipolar structure, which features a nonrecessed base and a selectively deposited polysilicon emitter, is proposed. The in situ surface cleaning process prior to the selective-polysilicon deposition minimizes the residual native oxide in the emitter window. Both high-quality selective-polysilicon film and well-behaved submicrometer bipolar device characteristics have been obtained for bipolar or BiCMOS VLSI applications. The effects of the nonrecessed-base device structure on the bipolar device parameter distribution and bipolar hot-carrier immunity are also discussed.<
>