Gate Reliability Investigation in Normally-Off p-Type-GaN Cap/AlGaN/GaN HEMTs Under Forward Bias Stress

Gate reliability of normally-off p-type-GaN/AlGaN/GaN high-electron mobility transistors grown on Si substrate subjected to forward bias stress at different gate voltages and temperatures was analyzed. Stress-induced gate current degradation was found to be consistent with the percolation process. Obtained time-to-breakdown data were interpreted using the Weibull statistics, and the maximum allowed gate operating voltage was estimated. The gate degradation was found to be weakly dependent on temperature with an activation energy of 0.1 eV.