X-ray scattering from etched and coated multilayer gratings

Abstract

Etched and coated multilayer gratings and simple multilayers are investigated by means of x-ray scattering (XRS) and grazing x-ray reflectivity (XRR). Two types of gratings are studied: one lamellar grating coated by a La/B4C stack and two lamellar gratings etched in a Mo/B4C multilayer structure with different cyclic ratios. XRS measurements are presented as reciprocal space mappings or Q-mapping and the origin of the different structures observed in the Q-mapping are discussed in terms of typical coherent and diffuse scattering processes (Bragg spots, grating-Bragg spots, Bragg sheets, grating diffuse sheets, Yoneda wings, etc). From the XRS and XRR measurements, some structural parameters of the mirrors and gratings such as periods and roughness characteristics are estimated.