Influence of dislocation clusters on homoepitaxial layers grown by halide vapor phase epitaxy (001) β-Ga2O3 investigated by synchrotron x-ray topography and scanning transmission electron microscopy

Abstract

Pit formation on the as-grown halide vapor phase epitaxy (001) β-Ga2O3 surface was primarily attributed to dislocation clusters in the substrate. Cross-sectional x-ray topography showed that these clusters penetrate to a minimum measured depths of roughly 210 μm below the (001) surface. Etch pit formation of the dislocation cluster revealed a distinctive type of etch pits, where the main etch pits are accompanied by smaller etch pits aligned at angles of approximately ±38° relative to the [010] direction near the head of primary etch pit. Further analysis by cross-sectional scanning electron microscopy observation confirmed that these smaller pits arise from (10¯2¯5) and (10¯25) stacking faults, which are speculated to serve as propagation paths for the dislocation clusters.