Epitaxial lateral overgrowth of <i>c</i>-plane <b> <i>α</i> </b>-Ga2O3 using a stripe mask with ultra-narrow windows

We demonstrated the epitaxial lateral overgrowth of α-Ga2O3 by halide vapor phase epitaxy using a stripe mask with an ultra-narrow window width of 50 − 750 nm. α-Ga2O3 stripes were formed only on the windows without unintentional nucleation on the mask, even on the mask with the narrowest window. Etch pit observations and cross-sectional transmission electron microscopy revealed that the propagation of dislocations into the regrown α-Ga2O3 was dramatically reduced by narrowing the window. The overall dislocation density in the coalesced film, including the window region and coalesced boundaries, was as low as 4 × 107 cm−2 in the case of the 50-nm window mask. We believe these results strongly contribute to the realization of α-Ga2O3-based high-performance future power devices.