Selective-area and lateral epitaxial overgrowth of III-N materials by metalorganic chemical vapor deposition

We describe the characteristics of single-crystal GaN regions obtained by selective-art a and subsequent lateral epitaxial overgrowth using metalorganic chemical vapor deposition. For a range of deposition conditions, the surface kinetics of the metalorganic chemical vapor deposition process results in an initial stage of selective-area growth, subsequently followed by the lateral growth of single-crystal GaN over the SiO2 mask. The lateral-to-vertical relative growth rate depends upon the orientation of stripe openings with respect to the GaN crystal planes, the ratio of the "open" stripe width to the "masked" stripe width, and the specific growth conditions (e.g., temperature and V/III ratio). The crystalline orientations of the growth facets on the sidewalls of the laterally growing stripes are also dependent upon the growth conditions. The results of cathodoluminescence and transmission-electron microscopy studies of the GaN films indicate that materials with improved quality are grown over the oxide mask. (C) 1998 Elsevier Science B.V. All rights reserved.