Comparative study of AlGaN/GaN heterostructures grown on different sapphire substrates

Abstract AlGaN/GaN heterostructures were grown on the conventional planar sapphire substrate (CSS), nano-scale patterned sapphire substrate (NPSS) and micro-scale patterned sapphire substrates (MPSS) by metal organic chemical vapor deposition respectively. The heterostructure grown on the MPSS has significantly lower threading dislocation density (TDD) than those grown on the NPSS and CSS. The bending and quenching of threading dislocations induced by lateral growth are the main factors for the reduction of TDD. Correspondingly, the carrier mobility of heterostructure grown on the MPSS is also the highest.