Low Cost, 50 GHz Fmax Si/SiGe Heterojunction Bipolar Transistor Technology with Epi-Free Collector Wells

We present a SiiSiGe heterojunction bipolar transistor (HBT) technology, designed to achieve high performance with minimum technological expense. For the HBTs, polysilicon was used only as emitter contact layer. The collector wells were formed by implantation, giving up the epitaxial construction with highly doped subcollectors commonly used for bipolar devices. Nevertheless, we demonstrate HBT peak l/ fmax values in excess of 40/ 50 GHz, ring oscillator delays down to 22 ps, and noise figures of less than 2 dB @ 2 GHz and 3 dB @ 10 GHz.