Change of high-voltage conduction mechanism in vertical GaN–on–GaN Schottky diodes at elevated temperatures

Current-voltage-temperature characteristics (0 °C to 150 °C) of SBDs on highly compensated 15 μm and 30 μm n-type GaN drift layer were measured for voltages up to −300 V and up to −800 V, respectively. When the temperature is between 75 °C and 100 °C, both SBDs exhibited a similar change in conduction mechanism from thermionic field emission (TFE) to thermionic emission (TE) due to the activation of N-vacancies (VN) (Ea = −1.67 ± 0.02 eV). However, at high voltages when the temperature is >100 °C, the conduction mechanism changes from TE to TFE due to the de-trapping of electrons from activated carbon-traps (Ea = +0.69 eV) in the grown drift layers.