X-RAY-DIFFRACTION MEASUREMENT OF PARTIALLY CORRELATED INTERFACIAL ROUGHNESS IN MULTILAYERS

The existence of partially correlated roughness in multilayer thin films is demonstrated using x-ray diffraction diffuse-intensity distribution measurements. The method is generally applicable and produces, in addition to values of magnitudes of interfacial roughness and its lateral correlation length, a measure of the cross correlation between interfaces separated by intermediate ones. A simple phenomenological model can describe roughness in W/C multilayers prepared under standard conditions. A cumulative roughness function is used to show that the wavelength range in which the interfacial roughness predominates in these layers lies between 50 angstrom and 2000 angstrom and that the long-wavelength roughness replicates better than the short-wavelength roughness.