Growth of GaN free from cracks on a (111)Si substrate by selective metalorganic vapor-phase epitaxy

The selective metalorganic vapor-phase epitaxy of wurtzite GaN was performed on a (111) silicon substrate using SiO2 grid mask pattern. Within window regions of (0.2–0.5) mm×(0.2–0.5) mm, GaN films free from cracks were achieved. The full width at half maximum of the (0004) X-ray rocking curve was as narrow as 388 arcs and that of the band edge emission was 18.6 meV at 77 K. The band edge emission peak energy was redshifted. The redshift is reduced slightly in a sample grown on small windows. This suggests that the biaxial strain due to the thermal expansion coefficient mismatch is partly relaxed on small windows.