Epitaxial growth of crack-free GaN on patterned Si(111) substrate

High-quality GaN epilayers were grown on patterned Si(111) substrates by metalorganic chemical vapor deposition. Crack-free GaN epilayers were obtained by growing the GaN on the plateau of the patterned Si(111) substrate. A high-temperature AlN buffer layer improved the crystalline quality of the GaN epilayer. When the growth temperature of the AlN buffer layer was 1000°C, the GaN epitaxial layer showed a smooth surface and high crystalline quality. The dislocation density of the subsequently grown GaN layer was 2 × 10⁹ cm^-2, which is comparable to those of conventional GaN epilayers grown on sapphire substrate.