Epitaxial lateral overgrowth of r-plane α-Ga2O3 with stripe masks along <-12-10>

We demonstrated the epitaxial lateral overgrowth of (-1012) (r-plane) α-Ga2O3 using striped mask pattern along <-12-10>. α-Ga2O3 stripes with an asymmetric cross-sectional shape were formed selectively on the windows at the initial growth stage. They grew vertically and laterally to coalesce with each other, and a compact film was achieved. The film surface exhibited wave-like morphology with macro-scale inclined terraces and steps because of the asymmetric cross-sectional stripe shape. Transmission electron microscopy revealed that a domain originated from a window grew toward the inclined c-axis direction so as to cover the adjacent domain after the coalescence. As a result, the dislocations which propagated into the α-Ga2O3 stripe from the seed layer through the window did not reach the top surface because they were buried by the overgrowth of the adjacent domain.