Estimation of Thin Film Thickness Using the Williamson–Hall Decomposition

The strict orientation and the independence of thickness and microstrain of epitaxial thin films justify the implementation of the Williamson–Hall approach for decomposition of sources of broadening of the XRD peaks. The substitution of the dependence on the diffraction angle with the dependence on deposition time—the t-WH technique—makes possible a reliable estimation of the deposition rate for the established deposition process and, as a consequence, evaluation of the film thickness. Application of the t-WH technique for two or more XRD peaks improves the accuracy of the deposition rate estimation, but also allows direct determination of the instrumental broadening and estimation of the microstrain generated in the film grown with the established deposition process. Utilization of the t-WH technique is especially useful when the instrumental broadening is high and cannot be found in a simple way, like in the case of asymmetric geometry of XRD measurement. The t-WH technique provides information on thicknesses of bottom layers in the heterostructures when application of X-ray reflectivity is hampered by high attenuation of the X-rays in the top layer.