Bending of dislocations in GaN during epitaxial lateral overgrowth was experimentally studied by using transmission electron microscopy. The orientational dependence of the dislocation energy factor was calculated on the basis of anisotropic elasticity theory for different types of perfect dislocation in GaN. Image forces acted on dislocations during growth, and dislocations bent in order to achieve a minimum energy. The bending behavior depended upon dislocation type, and it was shown that the measured bending angles corresponded to the calculated energy minima. The results permitted quantitative deduction of the most advantageous epitaxial lateral overgrowth GaN mask direction to give the largest dislocation density reduction.

Bending of Dislocations in GaN during Epitaxial Lateral Overgrowth. S.Gradečak, P.Stadelmann, V.Wagner, M.Ilegems: Applied Physics Letters, 2004, 85[20], 4648-50