Study on extremely thin base SiGe:C HBTs featuring sub 5-ps ECL gate delay

A thin and heavily-boron-doped SiGe:C base was selectively grown by low pressure chemical vapour deposition (LPCVD). To achieve high-speed performance, we performed carbon doping in the base region and studied as-grown intrinsic base width scaled-down toward a thickness of 1 nm with high SiGe-epi process stability and high transistor yield. We achieved f/sub T//f/sub MAX/ of 170/204 GHz maximum clock frequency of 16:1 MUX in this HBT.