Homo-epitaxial growth on the N-face of GaN single crystals: the influence of the misorientation on the surface morphology

GaN single crystals are used as substrates for homo-epitaxial growth by MOCVD. Prior to growth, the N-face, or (000 1) plane, of the substrate crystals is polished to obtain off-angle orientations of 0, 2, and 4- towards the [1 1 (2) over bar 0] direction. The hillock density of the homo-epitaxial films grown on the misoriented substrates is decreased as compared with the layers grown on the exact N-face. However, in addition to the hillocks, triangular-shaped pits are formed on the films grown on the misoriented substrates. The formation of the triangular-shaped pits is described by the blocking of the anisotropic step-flow growth. (C) 2002 Elsevier Science B.V. All rights reserved.