Optimization of vertical profiles of SiGe HBT/BiCMOS by promoting emitter diffusion process

A new concept, promoting emitter diffusion (PED) process, by using high-temperature annealing, is proposed for fabricating high-performance SiGe HBTs. Both the cut-off frequency and maximum oscillation frequency exceeded 200 GHz when the annealing temperature was increased from 885/spl deg/C to 1000/spl deg/C. This PED process concept is based on the fact that the increased phosphorus diffusion can more than compensate for increased boron diffusion and decreased base thickness.