QUANTITATIVE MICROROUGHNESS ANALYSIS DOWN TO THE NANOMETER-SCALE

Cross characterizations of surface roughness of glassy materials have been performed using Atomic-Force Microscopy (AFM) and optical scatter ing techniques. The AFM measurements provide images of the surface hei ght contours from the micrometer down to the nanometer scale. From a t wo-dimensional (2D) Fourier analysis of the images, the roughness powe r spectrum is measured for a range of spatial frequencies from 0.04 mu m-1 up to 400 mum-1. An excellent agreement is obtained with parallel light scattering measurements of the surface roughness over the spatia l frequencies ranging from 0.05 mum-1 to 1.54 mum-1, corresponding to the overlap bandwidth reached by the two techniques. From the power la w dependence of the roughness spectrum vs. spatial frequency found on the whole range of AFM analysis, fractal properties of this self-affin e surface are discussed.