Reliability studies on GaN HEMTs with sputtered Iridium gate module

A new gate module with Iridium as a degradation resistant Schottky contact is developed. The technology for GaN based HEMT devices comprises sputtering of low stress Iridium contacts and subtractive pattern delineation. Robustness and reliability of the devices were investigated by step-stress-test, IDQ-test, storage test and DC life-test. Leakage currents during robustness tests remain at low and stable level. From storage tests no sign of diffusion in the gate module was detected. Accelerated testing estimates an expected lifetime of 108 h at 175 °C channel temperature.