Characterisation of high-k containing nanolayers by reference-free X-ray fluorescence analysis with synchrotron radiation

Using reference-free X-ray fluorescence analysis (XRF) in different geometries carried out in the laboratory of the Physikalisch-Technische Bundesanstalt at the electron storage ring BESSY II in Berlin various nanolayered systems have been investigated. As an example the investigation of Hf containing thin oxide layers is shown. For comparison reasons these samples have been also measured by X-ray reflectometry (XRR) in the PTB laboratory and by other partners within the ANNA project, which confirmed the thickness of the Hf containing top layers determined by XRF within their respective uncertainties. The XRF spectra were deconvolved employing the detector response functions to deduce the intensity of the corresponding Hf L3 fluorescence lines. The investigation of nanolayered systems especially in the lower energy range shows advantages, like different absorption conditions which allow for better dynamics and the suppression of the silicon fluorescence signal from the substrate, but needs more effort in determining the respective fundamental parameters.