Nonspecular x-ray-reflectivity study of partially correlated interface roughness of a Mo/Si multilayer

Nonspecular x-ray-reflectivity intensities were measured to characterize the interface morphology of a Mo/Si multilayer. Longitudinal off-specular scans and transverse scans at several multilayer peaks and valleys were carried out. For the analysis of the experimental data, a height cross-correlation function between different interfaces was derived for a model multilayer whose interfaces are partially correlated. The parameters related to the interface morphology were obtained by fitting the measured intensities within the distorted-wave Born approximation. The intermixing widths of the graded interfaces, the correlated interface roughness amplitude, and a vertical correlation length were obtained by analyzing the off-specular intensities. [S0163-1829(98)04615-3].