Non-Specular X-ray Scattering from Multilayer Structures

X-ray multilayer structures derive their utility primarily from the specular reflectance at the first order multilayer Bragg peak. Ideal x-ray multilayer structures would have composition modulation only along the direction of the sample normal (z direction) and would be homogeneous in the x-y plane. Ideal structures would thus exhibit only specular reflectance in the region of low scattering vector near the multilayer Bragg peaks. Structural inhomogeneities in the x-y plane within the multilayer (possibly arrising from the substrate) would give rise to diffuse non-specular scattered intensity in this region.