Influence of the lattice parameter of the AlN buffer layer on the stress state of GaN film grown on (111) Si

GaN films grown on (111) Si substrate with different lattice parameters of the AlN buffer layer by metal–organic chemical vapor deposition are studied. The stress states obtained by different test methods are compared and it is found that the lattice parameter of the AlN buffer layer may have a significant effect on the stress state in the initial stage of subsequent GaN film growth. A larger compressive stress is beneficial to improved surface morphology and crystal quality of GaN film. The results of further orthogonal experiments show that an important factor affecting the lattice parameter is the growth rate of the AlN buffer layer. This work may be helpful for realizing simple GaN-on-Si structures and thus reducing the costs of growth processes.