Transmission electron microscopic observations were made of the microstructures of epitaxial laterally overgrown GaN layers. Particular attention was paid to the behavior of horizontal dislocations. The epitaxial laterally overgrown layers were grown by means of metalorganic vapor-phase epitaxy. The facet planes of the layer were controlled by using the 2-step epitaxial lateral overgrowth technique. In the case of specimens 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 observations 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 the horizontal dislocations, the internal stress in the region over the mask-window of epitaxial laterally overgrown GaN was estimated to range from 0.01 to 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