Modeling of trap-assisted tunneling in AlGaN/GaN heterostructure field effect transistors with different Al mole fractions

Although significant progress has been achieved in GaN based high power/high frequency electronic devices, surface-related problems still need an immediate solution. In particular, leakage currents through Schottky contacts not only impede device reliability but also degrade power efficiency and noise performance in such devices. This article discusses the mechanism of leakage currents through GaN Schottky and AlGaN/GaN Schottky interfaces for both forward and reverse biases. A theoretical model for the calculation of currents based on trap-assisted tunneling is discussed. In the calculation the trap energy has been assumed as a fitting parameter which is about 0.48 eV for different Al mole fractions. The comparison of the results obtained with the existing experimental data in the literature shows a good agreement.