GaN HEMT reliability at 125 °C for 1000 hours

With the growing popularity of GaN HEMTs, the reliability of the transistors after prolonged exposure and use at high temperatures is of increasing importance. Previous work has shown that GaN FETs can operate at temperatures higher greater than 500°C for short amounts of time, but need to be tested at rated operating temperatures. In order to determine whether commercial GaN HEMTs can be reliable at a more typical operating temperature, three EPC parts were tested. The EPC2001, EPC2014, and EPC2015 parts were characterized before temperature testing with a curve tracer. The parts were tested at and above their rated voltage for 1000 hours at a constant 125°C. After the 1000 hours of testing, each EPC part was characterized again on the curve tracer. No failures were observed during the 1000 hours of testing, but during the posttest characterization the R_DS(ON) of all the parts increased, parts failed at their rated maximum of 6 V to the gate, and some of the EPC2014s failed at all voltages.