The temperature-dependent electrical characteristics of Schottky rectifiers fabricated with a SiO2 field plate on a freestanding n(-) gallium nitride (GaN) substrate were reported in the temperature range of 298-473 K. The Schottky barrier heights evaluated from forward current-voltage measurement revealed an increase of Schottky barrier height and series resistance but a decrease of ideality factor (n) with increasing temperature. However, the Schottky barrier heights evaluated from capacitance-voltage measurement remained almost the same throughout the temperature range measured. The Richardson constant extrapolated from ln(J(0)/T-2) vs 1/T plot was found to be 0.029 A cm(-2) K-2. A modified Richardson plot with ln(J(0)/T-2) vs 1/nT showed better linearity, and the corresponding effective Richardson constant was 35 A cm(-2) K-2. The device showed a high reverse breakdown voltage of 560 V at room temperature. The negative temperature coefficients were found for reverse breakdown voltage, which is indicative of a defect-assisted breakdown. (c) 2007 American Institute of Physics.
Temperature-dependent electrical characteristics of bulk GaN Schottky rectifier