High Breakdown Voltage AlGaN/GaN Metal–Insulator–Semiconductor High-Electron-Mobility Transistor with TiO2/SiN Gate Insulator

We report the fabrication of an AlGaN/GaN high-electron-mobility transistor (HEMT) with a high breakdown voltage by employing a metal–insulator–semiconductor (MIS) gate structure using TiO 2 /SiN insulators. We employed the TiO 2 /SiN gate insulator for the first time in a multilayered insulator structure MIS-HEMT. The gate leakage current was significantly reduced by employing the MIS structure, and the breakdown voltage characteristics of the fabricated MIS-HEMTs were 1.1 kV with an on-resistance of 15 mΩ cm 2 for a gate-drain length of L gd = 28 µm. The current collapse in the TiO 2 /SiN MIS-HEMT has been improved by employing a thin SiN film under the TiO 2 insulator. AlGaN/GaN MIS-HEMTs are promising not only for high-speed applications but also for high-power switching applications.