【Epitaxy Papers】Thermal annealing effects on β-Ga₂O₃/diamond (111) heteroepitaxial structures fabricated by radio frequency magnetron sputtering

      Researchers from the Kyushu University have published a dissertation titled "Thermal annealing effects on β-Ga₂O₃/diamond (111) heteroepitaxial structures fabricated by radio frequency magnetron sputtering" in Materials Letters.

Abstract

      Heteroepitaxial integration of β-Ga₂O₃ on diamond (111) has been achieved using radio frequency magnetron sputtering. The β-Ga₂O₃ epilayer exhibited a high level of in-plane stacking with {-201} parallel to diamond {111}, as confirmed by X-ray diffraction analyses. Pole figure stereographic projections effectively concluded the inoccupancy of (101) texture in the β-Ga₂O₃ film. The heterojunction preserved its mechanical integration, crystallinity, and heteroepitaxial characteristics up to 900 °C thermal annealing for 40 min. However, annealing at 1000 °C led to structural degradation, attributed to thermal graphitization at the C–O interface. Notably, post-fabrication thermal annealing at 900 °C significantly reduced the oxygen vacancy density in the β-Ga₂O₃ epilayer from 24.15 % to 15.07 %.

DOI：

https://doi.org/10.1016/j.matlet.2025.138753