Determination of the Height-Height Correlation Function of Rough Surfaces from Diffuse X-Ray Scattering

We show that the height-height correlation function of a rough surface can be determined from the diffuse X-ray scattering intensity by an explicit back-transformation without any model assumptions. This is in contrast to the conventional fitting procedure of the data with parameterized correlation functions. The method is illustrated by the example of an amorphous Zr-35 Co-65 film evaporated on a silicon substrate with native oxide. The height-height correlation function obtained from the diffuse-scattering data is compared to the result of in situ STM measurements.