The morphology of the (001) β-Ga2O3 homoepitaxially grown film on on-axis and 6° off-axis toward 1¯00 substrates by metalorganic vapor phase epitaxy were investigated by adjusting Ga supersaturation via molecular flow rate O2/Ga ratio. The growth conditions were guided by the step-flow growth model previously established for (100) β-Ga2O3 film growth with a 4° off-axis miscut toward 001¯. The intentional miscut in the (001) β-Ga2O3 substrate was found to facilitate the groovy morphologies, but may not preclude the (4¯01) twins, while increasing Ga supersaturation leads to groovy morphologies for the grown film on off-axis (001) substrates and islands formation for the grown film on on-axis (001) substrates at 800 °C; however, only the multistep arrays have been obtained in the grown film on on-axis (001) substrates at 700 °C with the same Ga-supersaturation ranges, indicating an island suppression. An anisotropic kinetic growth model was introduced to explain the observed groove directions. These morphologies may be partially attributed to the (100) twin plane.
Chen et al. (2026) studied this question.