A method, based upon photo-electrochemical wet etching, was used to investigate defects in laterally overgrown layers by means of scanning electron microscopy. The latter images illustrated that the dislocation density in the homoepitaxial growth region was much higher than that in the laterally overgrown region. It was also possible to distinguish regions, with a high density of defects, from the perfect region. It was confirmed that the quality was greatly improved by using the epitaxial lateral overgrowth technique.

Investigation of Dislocations and Defects in Epitaxial Lateral Overgrown GaN by Photoelectrochemical Wet Etching. F.Wang, R.Zhang, X.Q.Xiu, K.L.Chen, S.L.Gu, B.Shen, Y.D.Zheng, T.F.Kuech: Materials Letters, 2003, 57[8], 1365-8