Leakage current mechanisms of groove-type tungsten-anode GaN SBDs with ultra low turn-ON voltage and low reverse current

In this work, we report a high-performance lateral GaN Schottky barrier diode (SBD) with a low turn-on voltage (VON) of 0.39 V and low reverse current. Meanwhile we have proposed a model to comprehend the leakage current mechanism in this GaN SBDs. The reverse current transport mechanism was analyzed by temperature-dependent current-voltage (T-I-V) measurements. The results indicate that reverse current is dominated by thermionic emission (TE), Frenkel-Poole (FP) emission and trap assisted tunneling (TAT) near zero bias, at low and high reverse bias, respectively. The thermionic field emission (TFE) is found to be the main mechanism near the breakdown voltage (BV). The comparison shows Al2O3 passivation layer can effectively reduce leakage current.