The morphological change of epitaxial lateral overgrowth (ELO) GaN during the hydride vapor phase epitaxy process has been investigated from the viewpoint of the effect of carrier-gas species. The lateral growth rates for using the carrier gas of only N-2 are higher than those for using the H-2 + N-2 mixed carrier gas. In the case of SiO2 stripe masks along the <1 (1) over bar 00> direction of the underlying GaN, {11 (2) over bar2} and {33 (6) over bar2} facets are observed in the sidewalls of ELO GaN for using the H-2 + N-2 mixed carrier gas. Results of cathodoluminescence and X-ray diffraction measurements suggest the crystal quality of the ELO GaN grown in the H-2 + N-2 mixed carrier gas is better than that in the N-2 carrier gas. (C) 2002 Elsevier Science B.V. All rights reserved.