Exploring physical mechanisms for sudden beta degradation in GaAs-based HBTs

Sudden beta degradation typically characterizes device failures in state-of-the-art GaAs-based HBTs under elevated temperature and current stress. Recombination enhanced defect reaction (REDR) processes may be responsible for this degradation. In this work, we review key experimental observations and possible physical mechanisms governing beta degradation which have been suggested in the literature. A simple REDR model for quantifying increases in the base-emitter depletion region trap density is first refined and then extended to model some types of premature failures.