Effect of Drain Bias on Degradation of AlGaN∕GaN High Electron Mobility Transistors under X-Band Operation

Sub-micron gate length AlGaN/GaN high electron mobility transistors were electrically stressed at 10 GHz at various drain bias conditions under 3 dB compression. The output power and drain current degradation was minimal up to drain bias of 20 V. Rapid degradation was observed at a threshold drain bias of 25 V. While most RF and DC device characteristics exhibited negligible change up to 20 V drain bias conditions, the Ni/Au Schottky contact showed considerable degradation at all drain bias conditions with an increase in gate leakage current, threshold voltage and Schottky barrier height.