X-Ray scattering from surfaces and interfaces

Abstract

The theory of X-ray scattering from surfaces is reviewed. A simple kinematical derivation is given of the surface truncation rods occurring near Bragg reflections and of the specular reflectivity. The dynamical theory is then discussed and it is shown that the 1/θ² tails in the theory arise from kinematic surface scattering, and, furthermore, also have the same origin as the specular reflection for θ > θ_c. The effect of surface roughness is then described. The techniques are then used to analyse X-ray measurements of the photodissolution of silver into As₃₀S₇₀. X-ray measurements are performed of the powder scattering from the thin silver layer, of the reflectivity and of the off-specular scattering at small angles. By combining all of these a detailed picture of the dissolution process is constructed. The process is then used to construct a diffraction grating and this is studied by X-ray reflectivity to study in detail the lithographic process. The extent of the blurring of the steps is determined and a model of the strucure constructed.