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

Current-voltage-temperature characteristics (0oC to 150oC) of SBDs on highly compensated 15µm and 30µm n-type GaN drift layer were measured for voltages up to -300V and up to -800V, respectively. When the temperature is between 75oC and 100oC, 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=-1.67eV). However, at high voltages when the temperature is >100oC, the conduction mechanism changes from TE to TFE due to the de-trapping of electrons from the activated carbon-traps (Ea=+0.69eV) in the grown DLs.