Micron-size V defects were found on the hydride vapor phase epitaxy grown GaN films. When the film thickness increased, the diameter of V defects increased, but the density of the defects decreased. The defect has six {1 1 0 1} facets, which encircle to form a concave hexagonal pyramid. Its shape is similar to that of epitaxial lateral overgrowth (ELO) GaN crystal grown on a dot-patterned GaN underlying layer. Through the analysis of the growth mechanism of ELO GaN, the growth mechanism of the V defects was investigated. (C) 2003 Elsevier Science B.V. All rights reserved.