Low stress, low defect density GaN was successfully grown on circle array patterned Si (111) substrate using AlN as the buffer followed by two steps growth of the GaN film. Raman measurement shows a reduction of in plane biaxial stress for the GaN film grown on patterned substrate. The slight blueshifL of PL peaks further provides evidence that the tensile stress in the GaN film was relaxed, It is believed that the grain boundaries of the polycrystalline AlN buffer layer and the dislocations in the GaN film grown helped to relieve the stress induced by the lattice and the thermal coefficient mismatches during growth. (C) 2014 Elsevier By. All rights reserved.