Application of a cluster tool for control of bipolar polysilicon emitter transistor characteristics

摘要

Abstract: A cluster tool technique featuring a vapor HF cleanfollowed by controlled growth of a thin interfacialoxide prior to polysilicon deposition is described. Thetool is used in the fabrication of polysilicon emittercontact bipolar transistors. Parametric data show thatbase current and beta vary systematically with oxidethickness but other device parameters remain unchanged.An initial assessment of run-to-run-processreproducibility is also described. The tool hassignificant potential for future BiCMOS processes whichwill require precision control of the interfacial layerand low- temperature processing.!9