Transit times of SiGe:C HBTs using nonselective base epitaxy

摘要

This paper reports an extensive investigation of high frequency figures of merit versus temperature carried out on SiGe:C bipolar transistors with several base doping and activation annealing conditions. The best f_T's are 188 and 278 GHz at 300 and 75 K, respectively. Contributions to total emitter collector delay are discussed and an original method based on collector capacitance measurement is proposed to calculate the collector transit time.