Effect of Anode Material on the Sensitivity of GaN Schottky Barrier Diode Temperature Sensor

GaN Schottky barrier diode (SBD) temperature sensors with TiN, Ni, and NiN anodes were fabricated in this study to evaluate the effect of anode material and inhomogeneous interface on the sensitivity. The temperature-dependent current–voltage curves negatively shift with the increasing temperature, presenting a slight inhomogeneous barrier behavior. Compared with the Ni anode, the TiN and NiN anodes suppress the inhomogeneity. The sensitivity obtained from the sub-threshold region follows the same tendency for all the SBDs, which increases with the decreasing current level. Furthermore, the NiN anode temperature sensor shows slightly higher sensitivity and better linearity compared with the Ni and TiN anodes, with the highest sensitivity of 2.54 mV/K. The discrepancy between the measured sensitivity and the theoretical value is ascribed to the inhomogeneous interface barrier.