113-GHz f/sub T/ graded-base SiGe HBT's

A novel low-thermal cycle process was used to fabricate epitaxial SiGe-base heterojunction bipolar transistors (HBTs) with record unity current gain cutoff frequencies. The process includes an in situ phosphorus-doped polysilicon emitter which requires only a 800 degrees C-10-s anneal. A peak f/sub T/ of 113 GHz at V/sub CB/ of 1 V was obtained for an intrinsic base sheet resistance of 7 k Omega / Square Operator .