X-Ray diffraction and reflectivity

Abstract

A concise review of X-ray diffraction (XRD) and reflectivity (XRR) analytical methods is presented. Basic concepts required for proper data acquisition and interpretation are introduced with several graphs and diagrams: X-ray scattering and diffraction processes, the concept of atomic interspacing d, Bragg’s law, reciprocal space and Ewald sphere. The key features from conventional XRD results are discussed, in combination with a review of modern instrument configurations, proper choice of optics and types of sample and detector scans. Powder diffraction analysis methods are presented by using a walk-through practical example: search/match phase analysis, preferred orientation, crystallite/grain size estimation, structure determination and Rietveld refinement method. Extensive discussion of thin film analysis by XRD and XRR is presented with focus on texture, lattice mismatch, strain relaxation and defects. High resolution reciprocal lattice mapping is presented in detail including discussion of a complex layered structure. Finally, XRR methods are presented with focus on thin film, density and roughness determination. Strength and limitations of each method are presented in comparison with competing analytical techniques.