High Power InP/Ga(In)AsSb DHBTs for Millimeter-Wave PAs: 14.5 dBm Output Power and 10.4 mw/μm² Power Density at 94 GHz

We report the 94 GHz large-signal load-pull performance of (0.3 × 9) μm2 InP/Ga(In)AsSb double heterojunction bipolar transistors (DHBTs) in the common-emitter (CE) and common-base (CB) configurations. Both configurations were implemented side-by-side on either 20-nm-thick graded GaAsSb- or GaInAsSb-base layers. A measured record saturated output power POUT,SAT = 14.5 dBm with a corresponding power density 10.4 mW/μm2 were achieved in the GaInAsSb-base CB configuration. The performance follows from i) the higher power gain in the CB topology and, ii) the superior BVCEO and BVCBO breakdown voltages obtained with the quaternary base which allow degradation-free operation at higher voltages. Load-pull contours show a combination of high output power and power gain in the proximity of 50 Ω for a wide range of load impedances. In contrast, CB InP/GaAsSb DHBTs deliver POUT,SAT = 10.6 dBm and 4.3 mW/μm2. For all devices considered here, CB operation improves transistor robustness against high-power device degradation. The present work provides the first report on the power performance of quaternary InP/GaInAsSb DHBTs in CE/CB topologies, with comparison to ternary InP/GaAsSb DHBTs.