Improved Off-State Stress Critical Voltage on AlGaN/GaN High Electron Mobility Transistors Utilizing Pt/Ti/Au Based Gate Metallization

The critical voltage for degradation of AlGaN/GaN high electron mobility transistors (HEMTs) employed with the Pt/Ti/Au gate metallization instead of the commonly used Ni/Au was significantly increased during the off-state stress. The typical critical voltage for HEMTs with Ni/Au gate metallization was around -60V. By sharp contrast, no critical voltage was observed for the HEMTs with Pt/Ti/Au gate metallization, even up to -100V, which was the instrumental limitation in this experiment. Both Schottky forward and reverse gate characteristics of the Ni/Au degraded once the gate voltage passed the critical voltage of around -60V. There was no degradation exhibited for the HEMTs with Pt-gated HEMTs.