Thermodynamic stability of Ga2O3(Gd2O3)∕GaAs interface

Ga2O3(Gd2O3)∕GaAs heterostructures have been annealed up to ∼780°C. Studies using x-ray reflectivity and high-resolution transmission electron microscopy have shown that the samples annealed under ultrahigh vacuum have maintained smooth and abrupt interfaces with the interfacial roughness being less than 0.2nm. The oxide remains amorphous, an important parameter for device consideration. Current–voltage and capacitance–voltage measurements have shown low leakage currents (10−8–10−9A∕cm2), a high dielectric constant of 15, and a low interfacial density of states (Dit) between gate dielectrics and GaAs. The attainment of a smooth interface between the gate dielectric and GaAs, even after high temperature annealing for activating implanted dopant, is a must to ensure the low (Dit) and to maintain a high carrier mobility in the channel of the metal–oxide–semiconductor field-effect transistor.