Analysis of InP/GaAsSb DHBT failure mechanisms under accelerated aging tests

We report on the reliability of InP/GaAsSb/InP DHBTs dedicated to very high-speed ICs applications. The devices under tests were fabricated by OMMIC [1]. Accelerated aging tests under thermal stress were previously performed on the same technology and the results are detailed in [2]. In this paper, we present the accelerated aging tests under bias stress performed on 15 DHBTs up to 2000 hours. The collector current density was fixed at 400 kA/cm 2 with various collector-emitter voltages V CE (from 1.5 V to 2 V) and various base plate temperature T a (from 30°C to 120°C). The associated junction temperature range is 80-180°C. From the Gummel characteristic, we observe that the major degradation mechanism is the base current decrease for V BE