A Comprehensive Study on the Reliability of GaN Transistors Under High Humidity, High Temperature, and Reverse Bias Conditions

The paper presents a detailed study of the reliability of GaN high-electron mobility transistors (HEMTs) under high-humidity, high-temperature, and reverse-bias (H³TRB) conditions. Despite growing interest, the number of studies addressing the reliability of GaN HEMTs remains limited. This work differs from previously published studies in its comprehensive approach; for example, the H³TRB test is conducted beyond standard specifications (i.e., at 95 % relative humidity) and at two different reverse-bias voltages (the maximum rated value and 80 % of that value). The drain–source leakage current was monitored during a 1000-h H³TRB test conducted on 11 GaN HEMTs in PowerFLAT 5×6 packages at a temperature of 85 °C. Key electrical characteristics were also measured before the stress test and at multiple time points after its completion (1 h, and for selected parameters also after 168 h) to assess the level of degradation and to investigate possible recovery phenomena. The results indicate that GaN HEMTs in PowerFLAT 5×6 packages exhibit high reliability under H3TRB stress for durations of at least 1000 h, with no catastrophic failures and no significant degradation in electrical characteristics, even under conditions of 95 % relative humidity and maximum drain–source voltage.