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 Ga 2 O 3 powder onto n -type GaAs substrates with the donor concentration N d = 2 × 10 16 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) × 10 12 eV −1 cm −2 .