AlGaN-GaN Metal-Insulator-Semiconductor High-Electron-Mobility Transistors With Very High-k Oxynitride TaOxNy Gate Dielectric

We investigated AlGaN-GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) with high-permittivity (high-k) oxynitride TaOxNy gate dielectric (k similar to 24) obtained by sputtering deposition. The MIS-HEMTs show excellent pulsed current-voltage characteristics, small off-leakage currents (<10(-10) A/mm), high on/off current ratios (> 10(10)), and favorable threshold voltage stabilities. From comparisons with MIS-HEMTs with TaOx gate dielectric, we conclude that N incorporation in gate dielectric can suppress current collapse and deep-level states.