Presentation Information
[10p-A21-9]High-Temperature Operation of N-polar GaN/AlGaN/AlN HEMTs with SiO2 Passivation
〇Amane Hayashiuchi1, Aina Hiyama Zazuli1, Nobuteru Hirata1, Yuuya Kitamura1, Satoshi Kurai1, Masanobu Hiroki2, Kazuyuki Hirama2, Yoshitaka Taniyasu2, Narihito Okada1 (1.Yamaguchi Univ., 2.NTT BRL.)
Keywords:
N-polar AlN,HEMTs
This work studies high-temperature operation of SiO2-passivated N-polar GaN/AlGaN/AlN HEMTs compared with unpassivated devices. The N-polar AlN layer enhances carrier confinement, reduces buffer leakage, and enables high-current operation. The structures were grown by MOVPE, and SiO2 was formed by PECVD. ID–VDS characteristics were measured in vacuum from room temperature to high temperature. In unpassivated device, drain current increased at low-to-middle temperatures but dropped rapidly at high temperature. This is attributed to competition between carrier supply from oxygen-related donors and degradation caused by phonon scattering and GaN surface instability. In contrast, the SiO2-passivated device suppressed current degradation and operated even at 900 °C. Leakage behavior suggests that oxygen-related donors, mobility reduction, electrodes, and surface states affect high-temperature operation. Overall, SiO2 passivation improves the thermal stability of N-polar GaN/AlGaN/AlN HEMTs.