A Monte Carlo technique for calculating the x-ray diffraction profiles from films with arbitrarily correlated dislocation distributions was presented. Both spatial integration and the integration over several dislocation ensembles were performed simultaneously. Explicitly consideration was given to the coexistence of misfit and threading dislocation ensembles with arbitrary correlations. Using these techniques, it was possible to reproduce quantitatively the experimental line-shapes for both thin (less than 100nm) and thick (more than 1000nm) GaN epitaxial films on SiC. The calculations explained the ubiquitous line-shape observed for thin highly-mismatched films, with a central coherent peak accompanied by exponentially decaying diffuse scattering.

X-Ray Diffraction of Epitaxial Films with Arbitrarily Correlated Dislocations: Monte Carlo Calculation and Experiment. V.M.Kaganer, O.Brandt, H.Riechert, K.K.Sabelfeld: Physical Review B, 2009, 80[3], 033306