Transmission electron microscopy observation was performed for microstructure in epitaxial lateral overgrown GaN layers with attention to the behavior of horizontal dislocations. The epitaxial lateral overgrown GaN layers were grown by metalorganic vapor phase epitaxy. The facet planes of the epitaxial lateral overgrown GaN layer were controlled by the two-step epitaxial lateral overgrown technique. In the specimen with a narrow mask-window of 3μm, horizontal dislocations were generated over the mask-window. In the case of a wider mask-window of 5μm, horizontal dislocations were also generated near to the mask-edge. Plan-view transmission electron microscopic observation showed that horizontal dislocations were formed in the shape of waves. The Burgers vector of the horizontal dislocations was perpendicular to the mask-edge. From the curvature of horizontal dislocations, the internal stress in the region over the mask-window of epitaxial lateral overgrown -GaN was roughly estimated to be 0.01-0.04GPa.

Distribution of Horizontal Dislocations in ELO-GaN. K.Horibuchi, S.Nishimoto, M.Sueyoshi, N.Kuwano, H.Miyake, K.Hiramatsu: Physica Status Solidi A, 2002, 192[2], 360-5