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) μm
²
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
P
_OUT,SAT
= 14.5 dBm with a corresponding power density 10.4 mW/μm
²
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
BV
_CEO
and
BV
_CBO
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
P
_OUT,SAT
= 10.6 dBm and 4.3 mW/μm
²
. 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.