Spectroscopic Polarimetry of Light scattered by Surface Roughness and Textured Films in Nanotechnologies.
The Effective Medium Approximation, (EMA), theory validate the thin films optical metrology in most cases when considering surface roughness. A scaling condition exist between the light wavelengths as compared to thin films roughness. In earlier papers, D. Ramsey1 and later P.I.Rovira and R.W.Collins2 ,S.F. Nee3, had shown however that poly crystaline and textured films could induce light scattering, affecting deeply the SE results. Exhaustives studies in the literature, detail the Mueller matrices properties through optical entropy and depolarization.It has been applied in rather different fields. The mathematical basis, describing depolarizing systems, developped by S.R. Cloude, are an important issue. In the visible range optics, complementary applications exist for thin grating films, surface scatterometry and biological turbid media The optical entropy provides a very powerful analysis technique yielding important surface parameters such as depolarization and roughness, differentiating roughness character, enabling even scatterer’s classification. As first results presented here, in thin films characterization for nanotechnologies materials, spectroscopic polarimetry specifies surface properties and films textures through an entropy concept. An ultraviolet extended range of present polarimeters set up for imaging and quality control, should be a promising enhancement compare to the present bidirectionals reflectance distribution function (BRDF) and haze ultraviolet wafer analysis of wafer in conventional processes.
Keywords: polarimetry, Müeller matrix, light scattering, optical entropy, nanotechnology material optical characterization