Influence of MgO and Sc2O3 passivation on AlGaN/GaN high-electron-mobility transistors

Unpassivated AlGaN/GaN high-electron-mobility transistors show significant gate lag effects due to the presence of surface states in the region between the gate and drain contact. Low-temperature (100 °C) layers of MgO or ${\mathrm{Sc}}_2{\mathrm{O}}_3$ deposited by plasma-assisted molecular-beam epitaxy are shown to effectively mitigate the collapse in drain current through passivation of the surface traps. These dielectrics may have advantages over the more conventional ${\mathrm{SiN}}_X$ passivation in terms of long-term device stability.