Crystal structure analysis of stacking faults through scanning transmission electron microscopy of beta-Ga2O3 (001) layer grown via halide vapor phase epitaxy

A crystal structure analysis of stacking faults (SFs) in a beta-Ga2O3 (001) layer grown by halide vapor phase epitaxy (HVPE) was performed using scanning transmission electron microscopy. Etch pits were formed on the surface using alkaline molten salt etching and were used as a fiduciary mark during the analysis. The results revealed three types of defects. These defects were generated in the HVPE-grown layer (propagation from the defects of the beta-Ga2O3 substrate grown using the edge-defined film-fed growth method played no role in the generation of these defects). The first type of defect involved SFs on the (-310) plane and resulted from the vacancy of gallium (Ga) atom sites of the GaO4 tetrahedral unit and the GaO6 octahedral unit. The second type involved SFs on the (1-11) plane and resulted from displacement of the GaO6 octahedral unit. The third type was presumed as a ribbon-folded defect with repeated SFs on the (111) and (7-27) planes or the (1-11) and (727) planes.