Controlled nucleation time for improving aluminum nitride growth

Abstract In this work, aluminum nitride (AlN) nucleation was varied at 30, 60 and 120 s as an attempt to reduce the surface roughness and the dislocation density of the overgrown AlN layer. By increasing the nucleation time up to 60 s, the surface became smoother and the dislocation density decreased. With 60 s of nucleation, the dislocation density can be as low as 8.63 × 108 cm -2. Under this condition, the formation of 3D growth improved. This, in turn, favored more dislocation inclination in the AlN layer. However, the 3D growth disappeared by prolonged nucleation for 120 s. As a result, no further improvement of the AlN layer was observed.