Structural characterization of lamellar multilayer gratings by x-ray reflectivity and scanning electron microscopy

Structural characterization of a fully etched amorphous W/Si multilayer grating with lateral periodicity 800 nm is performed by x-ray reflectivity. Grating truncation rod profiles have been calculated using a matrix modal eigenvalue approach of the dynamical theory of reflectivity by gratings which generalizes the Fresnel transmission and reflection coefficients for lateral diffraction. The interface roughness in rough gratings has been taken into account by a coherent amplitude approach which damps the generalized Fresnel coefficients. Scanning electron microscopy pictures complete the study.