The dislocation structures of thick hydride vapour phase epitaxial GaN layers, grown onto sapphire, were studied by analyzing the micro-distortion tensor components. Symmetrical reflections (including those from planes which formed large angles with the basal plane), using 2 scanning modes and 2 geometries (Bragg, Laue), were used to obtain the tensor components. The connections between tensor components and major dislocation types were considered. Various types of dislocation distribution were identified in thick GaN films which were grown on sapphire, with and without undoped and Si-doped metalorganic chemical vapour-deposited templates.

Determination of Microdistortion Components and their Application to Structural Characterization of HVPE GaN Epitaxial Layers. V.V.Ratnikov, R.N.Kyutt, T.V.Shubina, T.Paskova, B.Monemar: Journal of Physics D, 2001, 34[10A], 30-4