Deep traps in unpassivated and Sc2O3-passivated AlGaN/GaN high electron mobility transistors

Sc 2 O 3 thin-film layers deposited by rf plasma-assisted molecular-beam epitaxy were found to significantly reduce the concentration of prominent surface traps with activation energies of 1 and 0.9 eV on AlGaN/GaN high electron mobility transistors (HEMTs). The surface passivation is accompanied by effective mitigation of the current collapse observed under rf conditions in HEMTs without Sc2O3. The passivation is stable to post-deposition annealing temperatures of 400 °C and device degradation at higher temperatures is due to reaction of the gate metal with the AlGaN.