engleski

Lateral inhomogeneities in W/C multilayer mirrors

To obtain considerable reflectivity of hard X- rays by tungsten/carbon (W/C) multilayers for angles of grazing incidence > 2∘ requires a bilayer period of less than 2.5 nm and a high quality of the multilayer structure. In this work, a series of W/C multilayered stacks, with different C and W layer thickness and different power applied on the W target, have been prepared by sequential RF/DC magnetron sputtering. Information on the lateral W-layer homogeneity has been retrieved from grazing incidence small angle X-ray scattering (GISAXS) measurements. X-ray reflectivity (XRR) measurements have supplied additional information on the multilayer quality. W-layers thinner than 0.9 nm comprise isolated islands, while beyond a thickness of 1.4 nm homogeneous and continuous W-layers were formed. The evolution of the inter-island separation with the thickness of the W-layers follows a power law with an exponent of ∼ 0.37 ± 0.04. The growth of C-layers tends to smooth out the relatively high roughness of the island-like morphology of the preceding W-layers.

Tungsten-carbonThin films ; Multilayer ; Grazing incidence small angle X-ray scattering ; X-Ray reflectivity ; Film discontinuity

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