It was noted that epitaxial lateral overgrowth had proved to be an efficient technology for sharply decreasing the density of extended defects in the 107/cm2 range. In a so-called 2-step epitaxial lateral overgrowth process presented here, only the coalescence boundaries were defective. In this 2-step epitaxial lateral overgrowth modification, the tilt-angle between the 2 laterally overgrowing wings was found to be negligible. The thickness dependence of the crystal quality of an epitaxial lateral overgrowth GaN/sapphire was investigated by using a 50 x 0.5µm X-ray focused beam from a synchrotron storage ring. Micro-diffraction permitted monitoring of the mechanism of reduction of the density of extended defects. It was shown that no tilt occurred during the 2-step epitaxial lateral overgrowth process.

Structural Evaluation of GaN/Sapphire Grown by Epitaxial Lateral Overgrowth by X-Ray Microdiffraction. M.Drakopoulos, M.Laügt, T.Riemann, B.Beaumont, P.Gibart: Physica Status Solidi B, 2006, 243[7], 1545-50