ASSIGNMENT
Laboratory X-ray characterization tools and algorithms for thin films, multilayer structures and nano-patterns
Contact: Dr. ir. Igor Makhotkin (i.makhotkin@utwente.nl)
Level: BSc or MSc
Project nature: experimental, simulations and data analysis
X-ray based techniques are extensively used in many fields of industrial and academic research. Many years of research and development made some of the X-ray-based techniques automated for specific tasks. For example, a hand-held X-ray fluorescence scanner can determine the chemical composition of rocks during geological studies, automated X-ray diffraction is used for quality control in the pharmaceutical industry, and a thin film X-ray reflectivity is used in various semiconductor R&D fabs. Next to automated solutions there are extended set of laboratory X-ray based techniques capable of solving many complex characterization and metrology tasks when used by experienced researchers. The main challenge in such X-ray analysis is typically the reconstruction of the information from the measurements, that depending on the object illuminated by the X-rays can be solved either specifically or for generic cases. The reconstruction of a thin-film structure from measured data requires a complex approach of fitting calculated reflectivity from a model of thin-film to measured data, varying the parameters of the model fit.
At the XUV Optics group we extensively use and develop X-ray characterization techniques for thin films and nanostructures, such as X-ray diffraction (XRD), grazing incidence small-angle X-ray scattering (GI-SAXS), X-ray reflectivity (XRR), X-ray fluorescence (XRF) and X-ray standing waves (XSW). These techniques have the following benefits: they are non-destructive, compatible with ambient or gas atmosphere environment and capable of operando/in-situ measurements of thin-film processes (think of heat-induced diffusion for example).
Within this research, depending on your preferences, education and background, we can specify a Bachelor or Master’s research program in the field of X-ray metrology. For example, if you are interested in working with complex algorithms and data analysis strategies, you can work on the further development of state-of-the-art assumption-independent algorithms for thin-film characterization from XRR and XSW. If you are interested in an extension of your expertise in the chemical analytics you can work on enabling quantitative XRF for nm-thin films on our laboratory equipment.
The beauty of such projects is that the skills developed during the research in X-ray metrology will be useful for a large variety of research fields where thin films are applied, e.g. in photovoltaics, thin-film batteries research, and even in a life science research on lipid membranes.