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 scattering techniques. The AFM measurements provide images of the surface height contours from the micrometer down to the nanometer scale. From a two-dimensional (2D) Fourier analysis of the images, the roughness power spectrum is measured for a range of spatial frequencies from 0.04 mum-1 up to 400 mum-1. An excellent agreement is obtained with parallel light scattering measurements of the surface roughness over the spatial 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 law dependence of the roughness spectrum vs. spatial frequency found on the whole range of AFM analysis, fractal properties of this self-affine surface are discussed.