Sputtered-gate-SiO2/AiGaN/GaN MOSHEMT for high breakdown voltage achievement

By using RF magnetron sputtering with oxygen compensation, high-quality SiO₂-on-GaN with a breakdown field of 9.6 MV /cm was achieved. A post-annealing treatment was then developed to remove the sputtering-induced epilayer damage, which not only recovered, but also improved the electron concentration and mobility of the 2-D electron gas by 21.7% and 5.5%, respectively. A high-performance SiO₂ / AlGaN / GaN MOSHEMT was thus fabricated, which exhibited a maximum drain current of 594 mA/mm and a breakdown voltage of 205 V at the gate-drain distance of 2 μm. This breakdown voltage performance of the device is among the best of GaN-based MOSHEMTs reported to date, thus is ideally suited for high-power applications.