Correlated Diffuse X-ray Scattering from Periodically Nano-Structured Surfaces

TL;DR

This paper investigates the origins of correlated diffuse X-ray scattering from nano-structured surfaces, revealing how resonant and dynamic scattering contribute to the observed patterns, supported by finite-element modeling.

Contribution

It provides a detailed analysis of diffuse scattering mechanisms in nanostructured surfaces, enhancing surface geometry reconstruction methods.

Findings

Resonant diffuse scattering creates palm-like intensity sheets.

Dynamic scattering produces Yoneda and higher-order Yoneda bands.

Finite-element modeling supports the scattering origin explanations.

Abstract

Laterally periodic nanostructures were investigated with grazing incidence small angle X-ray scattering. To support an improved reconstruction of nanostructured surface geometries, we investigated the origin of the contributions to the diffuse scattering pattern which is correlated to the surface roughness. Resonant diffuse scattering leads to a palm-like structure of intensity sheets. Dynamic scattering generates the so-called Yoneda band caused by a resonant scatter enhancement at the critical angle of total reflection and higher-order Yoneda bands originating from a subsequent diffraction of the Yoneda enhanced scattering at the grating. Our explanations are supported by modelling using a solver for the time-harmonic Maxwell's equations based on the finite-element method.