Diffuse X-ray scattering from local chemical inhomogeneities in InGaN layers

Diffuse X-ray scattering from random chemical inhomogeneities in epitaxial layers of InGaN/GaN was simulated using linear elasticity theory and kinematical X-ray diffraction. The simulation results show the possibility of determining the r.m.s. deviations of the local In content and its lateral correlation length from reciprocal-space maps of the scattered intensity. The reciprocal-space distribution of the intensity scattered from inhomogeneities is typical and it can be distinguished from other sources of diffuse scattering such as threading or misfit dislocations.