Application of off-specular X-ray reflectivity for surface characterization

A scheme based on the distorted wave Born approximation has been developed to model the off-specular x-ray reflectivity from flat surfaces with compositional and topographic fluctuations.(1) To verify this theoretical work, silicon wafers coated with evenly spaced aluminum lines were chosen as the test samples. Good agreement is found between the calculationed and the experimental results. In addition, a gross difference in the off-specular spectra was observed from two test samples different only in their surface roughness; this observation demonstrates the potential of using off-specular x-ray reflectivity for quality control measurements.