Utilization of conventional PXRD apparatus for characterization of thin-films using reconsidered equations for XRR

Abstract

Conventional powder X-ray diffraction (PXRD) device in Bragg-Brentano configuration was utilized to derive X-ray reflectivity (XRR) measurements of a thin-film without technical specifications provided by the supplier. XRR was reviewed as one of the methods for fast thin-film characterization on behalf of modified equations for quantification of thin-film parameters. We evaluated the feasibility of a conventional PXRD device for an acceptable description of thin-films using the equations for assessment of density, thickness and roughness, modified in manner to address incomplete angular data. We correlated approximations to relative errors. The PXRD-obtained thickness for the sample was 27 nm. The PXRD results were compared with the results obtained using methods that presume some knowledge on the thin-film composition. Ellipsometry considers the thin-film as 61 nm thick metallic-metallic oxide bilayer. Scanning electron microscopy (FESEM) pointed out to homogeneous Ni,Cr-based thin-film sample with a thickness of about 50 nm. Ambiguous FESEM results were corrected with atomic force microscopy (AFM), suggesting a monolayer thickness of 28 nm. Finally, synchrotron XRR allowed the best possible geometry and signal acquisition quality confirming the monolayer with thickness of 27 nm. In conclusion, we find the PXRD setup to be an equally precise method. However, the method shows limitations for complex multilayer thin-film configurations having similar refraction properties. The method can be recommended for thin-film characterization, however, it is not completely self-standing.