High-Temperature TDDB Investigation on High Performance-Centered Hybrid HZO/HfON/Al₂O₃, Ferro-Electric Charge-Trap (FEG) GaN-HEMT

This article investigates a hybrid ferroelectric charge trap (HFCT)-based HfZrO₄/HfOXNY/ Al₂O₃/AlGaN/GaN gate-stack under constant positive gate voltage stress over time and temperature variability. The experimentally characterized breakdown (BD) analysis implies a thermally assisted tunneling (TAT) BD owing to the negative temperature coefficient of BD voltage. Moreover, the step gate stress depicts a relatively lower BD voltage of 20 V compared to the linear gate stress voltage of 21.85 V attributed to performance degradation due to stress. In addition, the Weibull distribution, which validates the intrinsic degradation of the gate-stack, is used to estimate its lifetime. An operating voltage of 7.41 V exhibits a ten-year lifetime at 150 °C extrapolated over multiple stress conditions. Furthermore, the activation energy from 0.63 to 0.67 eV validates deep-level E3 traps within the GaN barrier layer and the trapping of electrons during degradation, thus, revealing the point-level defect generation leading to the time-dependent gate dielectric BD (TDDB). The robustness and superior reliability of the HFCT gate-stack are recognized, and the single degradation mechanism contributes to the final device failure in the TDDB test.