Speckle in coherent x-ray reflectivity from Si(111) wafers

Reconstruction of surface morphology from coherent x-ray reflectivity

“…The experimental geometry for surface CXD employed a coherent x-ray beam at grazing-incidence angle and examined the resulting distribution of intensity near to the specular direction. 7 This geometry was very similar to that used previously for studying the multilayers, again with the result that the CXD pattern was one dimensional. The restriction to Bragg diffraction no longer applies in the specular reflectivity case and so the perpendicular momentum transfer, q z , can be varied in a continuous manner.…”

“…7 While incoherent x-ray reflectivity from a rough surface would give rise to a superposition of pure specular and diffuse components, 8 the equivalent CXD experiment yields a speckle pattern that intermixes both of these components: the specular component becomes broadened by the finite size of the illuminated sample area while the diffuse component adopts a finely speckled structure. The experimental geometry for surface CXD employed a coherent x-ray beam at grazing-incidence angle and examined the resulting distribution of intensity near to the specular direction.…”

Probing surface and interface morphology with Grazing Incidence Small Angle X-Ray Scattering

“…The first observations of coherent scattering from surface roughness [224][225][226][227] were performed in the reflectivity geometry. Due to this arrangement, the footprint of the beam on the sample is highly elongated such that its speckle pattern becomes one dimensional.…”

Effects of partial coherence on correlation functions measured by x-ray photon correlation spectroscopy

“…The scattered intensity distribution of such an x-ray beam coming from a rough surface provides a speckle pattern due to destructive and constructive interference. 12,13 At liquid or soft matter surfaces the roughness is generated by thermally excited capillary waves, and the related speckle distribution changes on the same time scale as the surface fluctuation. The measurements of the temporal intensity autocorrelation function of these speckles contain information about the dynamic properties of these surfaces.…”