TEM investigation of microstructure of semipolar GaN layers grown on nano-patterned Si(001) substrates

The synthesis of III-nitride binary compounds on commercial standard (001) silicon wafers by vapour-phase epitaxy is one of the promising directions for III-nitride technology development. However, the difference between crystal symmetry of Si(001) and wurzite (0001) surface structures is challenge that hinders the development. A use of silicon substrates with nano-patterned surface is one of the solutions to the problem. In this paper we present a transmission electron microscopy study of polar and semipolar GaN layers grown by halide vapour-phase epitaxy and metalorganic vapour-phase epitaxy on nano-patterned silicon (001) substrate. Crystallographic orientation relationships between the silicon substrate and GaN layers is identified. For GaN layers grown by metalorganic vapour-phase epitaxy an effect of SiC buffer layer synthesized by original growth method on their microstructure and surface morphology is under consideration.