Effects of surface treatments on isolation currents in AlGaN/GaN high-electron-mobility transistors

Abstract
Interdevice isolation currents in mesa-isolated AlGaN/GaN high-electron-mobility transistors are found to exhibit thermally activated behavior, with an activation energy of ∼1.5 eV. This value is largely independent of surface cleaning processes or the type of passivation film (SiNX, Sc2O3, MgO) used to reduce the current collapse phenomena in the devices. However, the magnitude of the isolation current is a strong function of the surface treatment employed. The lowest isolation currents for conditions under which current collapse is mitigated are obtained using Sc2O3 passivation layers.