Soft X-ray Reflection Spectroscopy for Nano-Scaled Layered Structure Materials

We introduce a novel approach that addresses the probing of interfacial structural phenomena in layered nano-structured films. The approach combines resonant soft x-ray reflection spectroscopy at grazing incidence near the "critical angle" with angular dependent reflection at energies around the respective absorption edges. Dynamic scattering is considered to determine the effective electron density and hence chemically resolved atomic profile across the structure based on simultaneous data analysis. We demonstrate application of the developed technique on the layered model structure C (20 Å)/B (40 Å)/Si (300 Å)/W (10 Å)/substrate. We precisely quantify atomic migration across the interfaces, a few percent of chemical changes of materials and the presence of impurities from top to the buried interfaces. The results obtained reveal the sensitivity of the approach towards resolving the compositional differences up to a few atomic percent. The developed approach enables the reconstruction of a highly spatio-chemically resolved interfacial map of complex nano-scaled interfaces with technical relevance to many emerging applied research fields.