Reliability Investigations on 650 V Schottky p-GaN Power Gallium Nitride HEMTs

Abstract:
A series of different lifetime tests has been performed on 650 V GaN HEMTs with Schottky p-GaN gate structure. The investigation includes: (i) high humidity, high temperature reverse bias (HV - H3TRB) test at 80 % of nominal voltage, 85% relative humidity and a temperature of 85deg C (ii) high temperature gate bias (HTGB) test with positive gate voltages (iii) power cycling test (PCT) to evaluate IG as temperature sensitive parameter (TSEP). The investigation was carried out respecting existing standards, but considering the Schottky p-GaN gate structure of the devices. At HV-H3TRB, package and device weak spots were found. During forward biased HTGB no failure, but increased drain and gate leakage currents occurred. The gate current IG was successfully applied as TSEP. Moreover, the investigated devices exhibit a high power cycling capability.