Study of the SiGe HBT based on the self-alignment and air-bridge

By using base-emitter self-alignment and air-bridge technology, the base resistance of SiGe heterojunction bipolar transistors(HBT) together with the capacitance between collector and base is reduced; in addition, the maximum oscillation frequency (f_(max)) is improved. In this paper, SiGe HBT f_(max) of (124.2GHz)has been obtained based on MBE SiGe materials.