Effect of epilayer microstructure on shape of X-Ray diffraction peaks

The X-Ray diffraction (XRD) reflections from epitaxial layers with various microstructures have been measured in the Bragg and Laue geometries. The shapes of XRD peaks measured in the theta and theta-2 theta scan modes have been analyzed using the approximation by the Voigt function. It is shown that, for the structures with more regular dislocation systems, the Gaussian component predominates, whereas a more chaotic distribution of dislocations leads to an increase in the Lorentzian component. Far on the wings of XRD peaks, the rate of intensity decrease exceeds that predicted by the Voigt function.