Regensburg 2016 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 35: Thin Film Characterisation: Structure Analysis and Composition II

DS 35.5: Vortrag

Mittwoch, 9. März 2016, 16:00–16:15, H8

Analysis of interface properties of multilayer mirrors with sub-nanometer layer thicknesses — •Anton Haase¹, Saša Bajt², Victor Soltwisch¹, Philipp Hönicke¹, Christian Laubis¹, and Frank Scholze¹ — ¹Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin — ²Photon Science, DESY, Notkestr. 85, 22607 Hamburg

The spectral range from 2.2 nm to 4.4 nm, also known as the water window, has a high relevance in the investigation of biological samples in a wet environment due to the low absorbance of these particular wavelengths in water. Multilayers composed out of Cr and Sc provide enough optical contrast to serve as mirrors for this wavelength range, while maintaining low absorption. However, a respective choice of layer thicknesses down to the sub-nanometer regime directly related to the desired peak reflectivity at a certain wavelength and angle of incidence are required. Disturbances of interfaces with respect to the ideal multilayer such as interdiffusion and roughness diminish the theoretically achievable maximum reflectivity. Experimental reflectivities show values below 20%, i.e. less than half of the theoretically achievable maximum. We show how the combination of several complementary experiments, such as EUV and X-ray reflectivity, resonant EUV reflectivity at the L-edge and X-ray standing wave analysis are necessary to obtain a consistent model. Based on this results a analysis of the diffuse scattering is performed to asses the interface roughness and determine a effective power spectral density.