Atomic Structure Based Simulation of X-Ray Scattering from Strained Superlattices

Abstract

The X-ray scattering from strained superlattices is simulated using the positions of all individual atoms, determined by minimizing the strain energy of the structure, and the kinematic approximation (atomistic kinematic theory, AKT). For thin epilayers the agreement with dynamical diffraction theory (DT) is very close in the vicinity of a reciprocal lattice point, even in the case of large strain. Serious flaws in two of the five tested, widely used commercial DT simulation programs are revealed. DT in the two-beam approximation yields incomplete large angle diffraction scans since the solution is developed around only one reciprocal lattice vector, while in AKT all possible scattering vectors are (implicitly) considered.