Structural characteristics of α-Ga2O3 films grown on sapphire by halide vapor phase epitaxy

While the importance of α-Ga2O3 crystals is increasingly gaining much interest, the structural behavior of halide vapor phase epitaxy (HVPE) α-Ga2O3 crystals in wet chemical etching has not been explored yet. In this study, we investigate the structural characterization of HVPE α-Ga2O3 materials via alkali KOH solution etching. Further, the activation energy of the etch rate for the materials, etch pit, and surface roughness after wet chemical treatment have been examined. The cross-sectional TEM analysis demonstrates that the triangular-shaped etch pits with (11 2‾ 6) plane are caused by the propagation of threading dislocations in the HVPE α-Ga2O3 crystals.