Model for degradation of GaAs/AlGaAs HBTs under temperature and current stress

Abstract

The similarities between GaAs/AlGaAs heterojunction bipolar transistors (HBTs) and GaAs-based light-emitting diodes (LEDs) and laser diodes (LDs) under current and temperature stress are demonstrated. Electroluminescence on HBTs with degraded current gain shows a marked decrease in light emission. One device which suffered rapid degradation in current gain also showed a <110> dark line defect (DLD). Finally, an equation used to model light output as a function of time under bias stress in LEDs and LDs was modified to model collector current vs. time for HBTs under bias stress. An excellent fit to the data is shown.