Orientation control of GaN {112¯2} and {101¯3¯} grown on (101¯0) sapphire by metal-organic vapor phase epitaxy

The growth of semipolar GaN on (101¯0) (m-plane) sapphire was investigated by metal-organic vapor phase epitaxy (MOVPE). Most of the layers were polycrystalline with {112¯2}, {101¯3¯} and {101¯0} as the dominant surface orientations. For incomplete nitridation and recrystallization the {101¯3¯} orientation was dominant. However, the {101¯3¯} surface is rough due to twinned crystallites. Growth at lower temperatures and with reduced gas flow velocity results in predominantly {112¯2} oriented smooth layers. The orientation was also found to be influenced by the nitridation and recrystallization process.