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

The heteroepitaxial beta-Ga2O3 films were grown on the (0 0 0 1) sapphire substrates with various off-angles toward < 1 1 (2) over bar 0 > by halide vapor phase epitaxy (HVPE). The effects of off-angled substrates on the surface morphologies and crystal quality of as-grown beta-Ga2O3 films were systematically investigated. The results indicated that the surface morphologies and crystal quality of beta-Ga2O3 films grown on the off-angled sapphire substrates were effectively improved, compared with that of the films grown on (0 0 01 ) sapphire. The quadrilateral domains growth mode was observed by scanning electron microscope and X-ray diffraction phi-scans of as-grown beta-Ga2O3 films. When the off-angle of (0 0 0 1) sapphire substrate was similar to 7 degrees, beta-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. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, the effects of off-angled sapphire substrates on the surface morphologies and crystal quality of heteroepitaxial beta-Ga2O3 films were systematically investigated. The results showed that the films grown on substrates with an off-angle of around 7 degrees exhibited a flatter surface morphology and better crystal quality, compared to films grown on (0 0 0 1) sapphire. These findings could be beneficial for the heteroepitaxy of high-quality Ga2O3 films with smooth surfaces.