FROM LIGHT-SCATTERING TO THE MICROSTRUCTURE OF THIN-FILM MULTILAYERS

It is shown how light scattering provides a powerful tool for thin-fil m characterization. The introduction of a roughness isotropy degree pe rmits the extraction of structural parameters of the stacks. Replicati on functions and residual roughnesses are given for TiO2, SiO2, and Ta 2O5 materials produced by ion-assisted deposition and ion plating. Add itional confirmation is given by measurements of scattering versus wav elength. The sensitivity of design to material and substrate effects i s studied. At low-loss levels, surface and bulk phenomena are discusse d together. Microstructure is characterized in the frequency bandwidth given by experiment.