Dissociation of [formula omitted] misfit dislocation at the interface of α-Ga2O3 thin film deposited on m-plane sapphire

Abstract

In this study, α-Ga2O3 films of thickness about 1 μm were epitaxially deposited on m-plane sapphire substrate by halide vapor phase epitaxy. The lattice mismatch between α-Ga2O3 and sapphire substrate is about 3.5 % along c-axis and 4.8 % along a-axis, resulting in the formation of misfit dislocations. High-angle annular dark-field scanning transmission electron microscopy was employed to study the misfit dislocations at the α-Ga2O3/sapphire interface. The study was carried out along the [112‾0] zone axis and focused on the dislocations responsible for a misfit strain relaxation along c-axis. The resulting magnitude of the projected Burgers vector onto (112‾0) plane has been compared with the estimated values for 13<1‾101> and 13<2‾021> dislocations. It has been revealed, that misfit dislocations tend to dissociate into partial dislocations at the interface.