Increased Current Gain and Reduced Emitter Resistance in Sige HBTs by Fluorine Or Chlorine Implantation into a Polysilicon Emitter Contact

This paper shows that fluorine implantation can be used to reduce the emitter resistance in a polysilicon emitter contact using a thermal budget that is compatible with SiGe technology. The influence of fluorine and chlorine on the base current is also investigated and it is shown that suppression by a factor of ~7 can be obtained in some circumstances.