Thickness determination for Cu and Ni nanolayers: Comparison of completely reference-free fundamental parameter-based X-ray fluorescence analysis and X-ray reflectometry

The layer thickness determined by both methods agreed within their combined uncertainties. In view of the limits of X-ray reflectometry for very thin layers, laterally inhomogeneous samples, and multi-elemental layer compositions, reference-free X-ray fluorescence analysis offers the potential for the thickness determination of such samples.