Gallium-oxide films obtained by thermal evaporation

The current-voltage (I–V), capacitance-voltage (C–V), and conductance-voltage (G–V) characteristics of metal/Ga _x O _y /GaAs/metal structures are investigated. Gallium-oxide films with a thickness of 150–170 nm are deposited by the thermal evaporation of Ga₂O₃ powder onto n-type GaAs substrates with the donor concentration N _d = 2 × 10¹⁶ cm^?3. Treatment of the Ga _x O _y films in oxygen plasma causes a decrease in both the forward and reverse currents and a shift of the C–V and G–V curves to higher positive voltages. The Fermi level at the insulator/semiconductor interface in the structures under study is unpinned. The density of states at the Ga _x O _y /GaAs interface is N _t = (2–6) × 10¹² eV^?1 cm^?2.