Quasistatic and high frequency capacitance–voltage characterization of Ga2O3–GaAs structures fabricated by in situ molecular beam epitaxy

Interface properties of Ga2O3–GaAs structures fabricated using in situ multiple‐chamber molecular beam epitaxy have been investigated. The oxide films were deposited on clean, atomically ordered (100) GaAs surfaces at ≂600 °C by electron‐beam evaporation using a Gd3Ga5O12 single‐crystal source. Metal–insulator–semiconductor structures have been fabricated in order to characterize the Ga2O3–GaAs interface by capacitance–voltage measurements in quasistatic mode and at frequencies between 100 Hz and 1 MHz. The formation of inversion layers in both n and p‐type GaAs has been clearly established. Using the quasistatic/high frequency technique, the interface state density has been derived as a function of band gap energy and a midgap interface state density in the mid 1010 cm−2 eV−1 range has been inferred. Charge trapping in the oxide has been revealed as the dominant trapping mechanism.