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Power Spectral Densities: A Multiple Technique Study of Different Si Wafer Surfaces



Egon Marx, I J. Malik, T Bristow, N Poduje, J C. Stover, Y Strausser, M J. Weber


The power spectral density (PSD) formalism is used to characterize a set of surfaces over a wide range of lateral (in-plane, x?y) as well as vertical (out-of-plane, z) dimensions. Twelve 200?mm-diameter Si wafers were prepared; the surface finish ranged from as-ground wafers to epitaxial wafers. The wafer surfaces were then measured with different methods: atomic force microscope, angle-resolved light scatter, interferometric and stylus profilometries, and capacitance-based wafer thickness gage. The data were converted into one-dimensional PSDs and plotted as functions of spatial frequencies. The data processing methods are presented in detail to show how meaningful results can be obtained. The useful frequency range for each method is outlined and the differences in the calculated PSD values in the overlapping region of two or more methods are discussed.
Journal of Vacuum Science and Technology


atomic force microscope, bidirectional reflectance distribution function, capacitance probe, power spectral density, stylus instrument, surface roughness


Marx, E. , Malik, I. , Bristow, T. , Poduje, N. , Stover, J. , Strausser, Y. and Weber, M. (2002), Power Spectral Densities: A Multiple Technique Study of Different Si Wafer Surfaces, Journal of Vacuum Science and Technology (Accessed April 23, 2024)
Created January 1, 2002, Updated February 19, 2017