Study of β-Ga2O3 films hetero-epitaxially grown on off-angled sapphire substrates by halide vapor phase epitaxy

Abstract

The heteroepitaxial β-Ga2O3 films were grown on the (0001) sapphire substrates with various off-angles toward 〈112-0〉 by halide vapor phase epitaxy (HVPE). The effects of off-angled substrates on the surface morphologies and crystal quality of as-grown β-Ga2O3 films were systematically investigated. The results indicated that the surface morphologies and crystal quality of β-Ga2O3 films grown on the off-angled sapphire substrates were effectively improved, compared with that of the films grown on (0001) sapphire. The quadrilateral domains growth mode was observed by scanning electron microscope and X-ray diffraction φ-scans of as-grown β-Ga2O3 films. When the off-angle of (0001) sapphire substrate was ~7°, β-Ga2O3 films exhibited the flatter surface morphology and the better crystal quality. The results would be helpful for the hetero-epitaxy of high-quality Ga2O3 films with smooth surface.