High breakdown AlGaN/GaN MOSHEMT with thermal oxidized Ni/Ti as gate insulator

Direct oxidation of composite Ni/Ti metal film structure for AlGaN/GaN MOSHEMT has been successfully demonstrated. In comparison with normal HEMT with Schottky-gate, transistors fabricated with this novel process exhibit three orders of magnitude reduction in gate leakage current, superior breakdown voltage (Vbr = 471 V vs. 88 V for normal HEMT) and electrical stability (∼0.3% electric field stress induced drain current degradation versus ∼6% for normal HEMT after 25 V drain bias). The drastic improvement in device performance stability, renders the new process highly promising for GaN based, microwave power amplifier applications in communication and radar systems.