High-resolution diffuse x-ray scattering from threading dislocations in heteroepitaxial layers

Diffuse x-ray scattering from epitaxial layers with screw dislocations perpendicular to the surface is calculated assuming correlated dislocation positions. The resulting intensity distribution was compared with a reciprocal-space map measured in a symmetric diffraction from a hexagonal GaN(0001) layer, and a good correspondence was achieved. From the fit, both the dislocation density and their correlation length were determined.