The role of gate leakage on surface-related current collapse in AlGaN/GaN HEMTs

The parasitic gate tunnelling of electrons into surface traps is shown to be responsible for the current collapse in GaN high electron mobility transistors. Simulations with and without surface traps are compared to pulsed output and gate leakage measurements and showed that the detrimental effect of surface traps is evident at positive gate voltages. Moreover, an apparent relationship between 2-dimensional electron density and Schottky reverse gate current is revealed in the presence of surface traps.