Positive and negative charge trapping GaN HEMTs: Interplay between thermal emission and transport-limited processes

This paper investigates the kinetics of buffer trapping in GaN-based normally-off high-voltage transistors. The analysis was carried out on transfer-length method (TLM) structures. By means a custom setup, (i) we investigated and de-trapping processes induced by large vertical bias identified different mechanisms, responsible for storage negative positive charge buffer. (ii) temperature-dependent to evaluate time constants associated build-up. Remarkably, results indicate that activation energy is ~0.3 eV, which much lower than ionization carbon acceptors (0.8–0.9 eV). result explained considering are not dominated thermal (thermal emission from acceptors), but transport limit transfer trap states. (iii) recovery experiments, after low stress dominates. After high bias, also effect generation detected, related evaluated. presented within this clearly GaN HEMTs interplay transport-limited conduction processes, (Ea ~ 0.3 eV), compared CN acceptors.