Fabrication of a-Ga2O3:Sn/a-Cr2O3/a-Al2O3 heterostructure by mist CVD and HVPE

Corundum-structured chromium oxide (a-Cr2O3), exhibiting p-type conductivity, is a highly attractive candidate for forming high-quality p-n heterojunctions with a-Ga2O3. Two CVD growth techniques were employed in the fabrication of the heterostructure. A ~ 0.2-micron a-Cr2O3 layer was grown on a (0001) sapphire substrate using mist CVD at 800 °C. It possesses high morphological homogeneity and low roughness, which is acceptable for further epitaxial processes. Subsequently, Sn-doped a-Ga2O3 with a thickness of ~ 1.5 µm was grown on the a-Cr2O3 layer using HVPE at 500 °C. The feasibility of fabricating this heterostructure with the specified layer thickness and acceptable surface morphology using CVD techniques has been demonstrated