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 congruent to 600 degrees 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 10(10) cm(-2) eV(-1) range has been inferred. Charge trapping in the oxide has been revealed as the dominant trapping mechanism. (C) 1996 American Institute of Physics.