High power and high cutoff frequencies of SiGe HBT

Si/SiGe heterojunction bipolar transistors (HBT's) have been fabricated by growing the complete layer structure with high vacuum CVD. The main device process is shown in this paper. Experimental results show that the device output power reached 0.5 watts and the cutoff frequency reached 18 GHz. The devices are propitious to high power and high frequency RF circuits.