HVPE growth of corundum-structured α-Ga2O3 on sapphire substrates with α-Cr2O3 buffer layer

Gallium oxide films were grown by HVPE on (0001) sapphire substrates with and without α-Cr₂O₃ buffer produced by RF magnetron sputtering. Deposition on bare sapphire substrates resulted in a mixture of α-Ga₂O₃ and ε-Ga₂O₃ phases with a dislocation density of about 2∙10¹⁰ cm^-2. The insertion of α-Cr2O3 buffer layers resulted in phase-pure α-Ga₂O₃ films and a fourfold reduction of the dislocation density to 5∙10⁹ cm^-2.