Influence of Lateral Growth on the Surface Pit Formation of GaN Heteroepitaxial Film Grown by MOCVD

  • Zhiyuan GAO
  • Xiaowei XUE
  • Huimin LI
  • Jiangjiang LI
  • Li MA
  • Wenrong WU
  • Deshu ZOU
Keywords: a-plane GaN, c-plane GaN, (11-22) semipolar GaN, surface pit, lateral growth


This study made an attempt to understand and control the heteroepitaxial growth of GaN from the view of the essential behaviors of crystal growth. Through a comparison of the nonpolar, polar and semipolar GaN epitaxial film, the influence of lateral growth on the surface pit formation mechanism has been investigated. For a-plane GaN, the lateral growth velocities of the less inclined {20-21} and {11-22} facets are approaching to the velocity of {10-11} facet under high temperature, so that the surface pit was transformed from a triangular shape to a pentagonal one. For c-plane GaN, the size of the surface pit produced by screw dislocation is determined by the lateral growth of the pit facets. A slow lateral growth rate of the inclined facets {10-11} compared with the vertical growth rate of (0001) facet under low V/III ratio would enlarge the pit size. For (11-22) semipolar GaN, surface pit is rarely observed, because the vertical growth velocity of {11-22} plane is slow compared with the lateral growth rate of the inclined facets, such as {11-20} and (0001).