The influence of punch-through in lowly doped collector on base for npn SiGe base HBTs with high f/sub T/

Abstract

In this paper, we have presented quantitative expressions of the collector space-charge-region (SCR) width of SiGe base HBTs with a lowly doped punch-through collector. Calculated results show a discontinuity occurs at the critical point between no punch-through and punch-through. The influence of the discontinuity on base and frequency performance has been discussed, Conclusions from our work may be also applicable to Si-BJTs.