CONTROL OF ANOMALOUS BORON-DIFFUSION IN THE BASE OF SI SIGE/SI HETEROJUNCTION BIPOLAR-TRANSISTORS USING PTSI/

In Si/SiGe/Si heterojunction bipolar transistor structures, very shall ow arsenic implant on the emitter has been found to cause anomalous bo ron diffusion in the base. This phenomenon imposes stringent constrain ts on the device fabrication processes. We discovered that by using pl atinum silicide, which also served as a self-aligned low resistance co ntact material to the emitter and base, the anomalous diffusion in the base was significantly reduced. In this letter, we report the experim ent results, and propose possible explanations.