Temperature dependent degradation modes in AlGaN/GaN HEMTs

This work is a study of the degradation of AlGaN/GaN HEMTs generated by different ageing tests. The methodology is based on cross-characterisation analyses. The life tests (HTO 175°C, HTO 250°C, HTO 275°C and HTO 320°C) have mainly caused a strong decrease of the drain current at the very beginning of the test, then its partial recovery and finally its collapse. No evident degradation of the Schottky contact is observed after stress at different temperatures. Moreover, pulsed I-V measurements show an important evolution of gate lag and drain lag rates after ageing. Low frequency drain current noise increases after the life test and the highest the life test temperature, the highest the noise level increase.