InGaP/GaAs Drift HBTs with High fT and /g=b/

InGaP/GaAs heterojunction bipolar transistors (HBTs) with an f_t = 126 GHz and a β = 162 have been demonstrated, and to the best of our knowledge this is the highest reported f_t, for an InGaP/GaAs HBT not employing a ballistic collection transistor design. The excellent dc and high frequency characteristics were achieved using a 300 Å thick graded base and a 2000 Å thick collector. These data show that InGaP/GaAs HBTs can simultaneously achieve both excellent dc and high frequency characteristics and that InGaP/GaAs HBTs are potentially useful in many high-speed circuit applications.