Samsung Advanced Institute of Technology

This work investigates the effect of an N₂O plasma treatment on the reliability of the p-GaN gate AlGaN/GaN high electron-mobility transistors (HEMTs), especially in the AlGaN drift region. The formation of GaON/AlON compound layer on the AlGaN surface after the N₂O plasma treatment was confirmed by Energy-dispersive X-ray spectroscopy (EDS) mapping and X-ray photoelectron spectroscopy (XPS) analysis. The compound layer not only reduces the number of negatively charged interface traps but also protects the AlGaN surface by hindering the Ga-out diffusion, when a device is under highly stressed conditions. The high temperature reverse bias (HTRB) reliability test demonstrated that N₂O plasma treatment enhanced the reliability of p-GaN gate HEMT by suppressing the degradation of the on-resistance (R_on) from 18.7％ to 9.0％, after being subjected to a high drain bias (V_DS = 700 V) at 200 °C for 1000 s.