Thermal and electrical stability assessment of AlGaN/GaN Metal-Oxide-Semiconductor High Electron Mobility Transistors (MOS-HEMT) with HfO2 gate dielectric.

Abstract

AlGaN/GaN HEMTs and MOS-HEMTs using HfO2 as gate dielectric have been analyzed at room temperature, after STA and TC test, during off-state electrical step stress, HTRB and PBTI tests. Results showed that the leakage current in as-fabricated MOS-HEMTs decreased by 106 and the on/off ratio increased by over 104 than the HEMTs. Moreover, it was even higher after a STA test, up to 108, in the MOS-HEMTs, and the surface trapping effects were mitigated, especially if a KOH cleaning was used before HfO2 deposition. The MOS-HEMTs also showed higher electrical stability after off-state step electrical stress, HTRB and PBTI tests.