Single-crystal atomic layer deposited Y2O3 on GaAs(0 0 1) - Growth, structural, and electrical characterization

Abstract

In situ atomic layer deposited (ALD) Y2O3 films 1-5 nm thick on GaAs(0 0 1)-4×6 reconstructed substrates were found to be single crystalline. The epitaxial growth between the oxide films and GaAs was first observed using reflective high energy electron diffraction (RHEED) and later studied using high-resolution synchrotron radiation X-ray diffraction. The Y2O3 films are of cubic phase and have (1 1 0) as the film normal; the orientation relationship between the Y2O3 films and the GaAs substrates was determined to be Y2O3(1 1 0)[0 0 1][1¯10]//GaAs(0 0 1)[1 1 0][11¯0]. The frequency dispersion of the measured capacitance-voltage (C-V) curves of the single crystal ALD-Y2O3/GaAs(0 0 1)-4×6 is ∼7% for p-GaAs and ∼14% for n-GaAs (1 M Hz to 100 Hz), lowest ever achieved in the ALD-oxides on GaAs(0 0 1).