Impact of gamma-ray irradiation on capacitance–voltage characteristics of Al2O3/GaN MOS diodes with and without post-metallization annealing

Abstract Atomic layer deposited Al 2 O 3 /GaN metal-oxide-semiconductor (MOS) diodes with and without post-metallization annealing (PMA) were irradiated with gamma-rays. Capacitance–voltage measurements were made before and after irradiation to investigate trap formation in Al 2 O 3 films and interface states between Al 2 O 3 and GaN. Negative flat-band voltage shifts were observed. The flat-band voltage shift depends on the Al 2 O 3 thickness, showing different distributions of gamma-ray-induced positive charges for samples with and without PMA. The interface state density of the PMA sample slightly increased after irradiation, but was lower than that of the sample without PMA before irradiation.