Development of metamorphic InP/InGaAs double heterojunction bipolar transistors (HBTs) on GaAs substrate for microwave applications

The device performance of InP/InGaAs double HBTs, including DC and microwave characteristics, have been carefully investigated. The MHBTs exhibit high current gain and common-emitter breakdown voltage with low junction leakages. An f_T and an f_max higher than 90 GHz were obtained for the devices with 1.6×5 μm² emitter area. Both microwave noise and power performances for the MHBTs are comparable to the conventional InP HBTs. More importantly, the issues which could be important for practical device application such as device thermal resistance, 1/f noise and device stability under high temperature and high current stress were carefully investigated. The results suggest a great potential of MHBTs for microwave applications.