600-V Normally Off ${\rm SiN}_{x}$ /AlGaN/GaN MIS-HEMT With Large Gate Swing and Low Current Collapse

In this letter, 600-V normally-OFF SiN_x/AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistor (MIS-HEMT) is reported. Normally-OFF operation and low OFF-state gate leakage are obtained by using fluorine plasma ion implantation in conjunction with the adoption of a 17-nm SiN_x thin film grown by plasma-enhanced chemical vapor deposition as the gate insulator. The normally-OFF MIS-HEMT exhibits a threshold voltage of +3.6 V, a drive current of 430 mA/mm at a gate bias of 14 V, a specific ON-resistance of 2.1 mΩ·cm² and an OFF-state breakdown voltage of 604 V at a drain leakage current of 1 μA/mm with V_GS=0 V, and the substrate grounded. Effective current collapse suppression is obtained by AlN/SiN_x passivation as proved by high-speed pulsed I-V and low-speed high-voltage switching measurement results.