Selective area growth (SAG) and epitaxial lateral overgrowth (ELO) of wurtzite GaN on (111) Si substrate by metalorganic vapor phase epitaxy

Selective area growth (SAG) of GaN on a (111) Si substrate using AlGaN as an intermediate layer by Metalorganic Vapor Phase Epitaxy (MOVPE) was studied. By optimizing the growth conditions, truncated hexagonal pyramids of GaN were obtained, and GaN polycrystals could not be observed on SiO₂ masks. Cathodoluminescence (CL) spectra at 148 K showed that the near-band-edge emission peak shifts towards low energy side in comparison with that of a GaN layer grown on a (0001) sapphire substrate. This suggests that the tensile strain due to the heteroepitaxy is given in the GaN pyramid on the Si substrate in contrast to the compressive strain of the GaN layer on the sapphire substrate.