High-Quality (0001) α-Ga2O3 Film Grown by Mist Chemical Vapor Deposition on (0001) α-Cr2O3 Template

A (0001) α-Ga2O3 film was grown by the mist chemical vapor deposition method on a (0001) α-Cr2O3 template (100 μm thick α-Cr2O3 layer formed on an α-Al2O3 substrate). Benefiting from the small a-axis lattice mismatch between α-Ga2O3 and α-Cr2O3, a high-quality α-Ga2O3 film with a small twist distribution, and consequently a low edge dislocation density, was coherently grown on an α-Cr2O3 template. The edge dislocation density of 7 × 107 cm−2, estimated from the full-width at half-maximum value of the X-ray rocking curve (XRC) in X-ray diffraction (XRD), was more than two orders of magnitude lower than that of the film grown on an α-Al2O3 substrate, and was almost consistent with that of the α-Cr2O3 template. The bright-field transmission electron microscopy (TEM) image supports the dislocation density estimated from the XRD measurements. The high-angle annular dark-field scanning TEM and inverse fast Fourier transform images indicate coherent growth, with almost no misfit dislocations generated at the α-Ga2O3/α-Cr2O3 interface.