Multiscale roughness in optical multilayers: atomic force microscopy and light scattering

Abstract

We have previously shown that macroscopic roughness spectra measured with light scattering at visible wavelengths were perfectly extrapolated at high spatial frequencies by microscopic roughness spectra measured with atomic force microscopy [Europhys. Lett. 22, 717 (1993); Proc. SPIE 2253, 614 (1994)]. These results have been confirmed by numerous experiments [Proc. SPIE 2253, 614 (1994)] and allow us today to characterize thin films microstructure from a macroscopic to a microscopic scale. In the first step the comparison of light scattering and atomic force microscopy is completed by optical measurements at UV wavelengths that allow us to superimpose (and no longer extrapolate) the spectra measured by the two techniques. In the second step we extract multiscale parameters that describe the action of thin-film coatings on substrate roughness in all bandwidths. The results obviously depend on materials and substrates and deposition techniques. Electron-beam evaporation, ion-assisted deposition, and ion plating are compared, and the conclusions are discussed in regard to the deposition parameters. Finally, special attention is given to the limits and performances of the two characterization techniques (light scattering and atomic force microscopy) that may be sensitive to different phenomena.

Reducing light scattering from surface contaminations by thin film design

“…These theories were experimentally verified to be very accurate [1,[12][13][14], but are limited to smooth surfaces with σ  λ (which, in fact, holds for the vast majority of optical coatings). In contrast to single surface scattering, predicting light scattering from multilayer coatings is more complex as interference effects have to be considered [15][16][17].…”

Micro Roughness Determination Of Periodic Microelectronics Structures Using Optical Far Field Measurements

“…To perform this validation, microscopy techniques (AFM or profilometry for example) can be used to performed multiscale analysis 10 .…”

“…This paper focuses on roughness determination by angle resolved scattering measurement. This choice has been motivated by the expertise of the Fresnel Institute in light scattering analysis [4][5][6][7][8][9][10] .…”

A self-affine geometrical model of dynamic RT-PMMA fractures: implications for fracture energy measurements

“…These fluctuations of G I dc are associated to the surface roughness and, more precisely, to the amount of created surface A r which varies significantly during fracture propagation (Kopp et al 2014a;Fond and Schirrer 2001;Osovski et al 2015;Srivastava et al 2014). Since the estimation of the amount of created fracture surface is typically a scale dependent measurement (Bouchaud 1997;Candela et al 2012), a multi-scale approach has to be considered (Deumié et al 1996) and several models exist to characterize this complex geometry (Mandelbrot et al 1984;Lopez and Schmittbuhl 1998;Ponson et al 1992;Bouchaud et al 1995).…”