From light scattering to the microstructure of thin-film multilayers

Abstract

It is shown how light scattering provides a powerful tool for thin-film characterization. The introduction of a roughness isotropy degree permits the extraction of structural parameters of the stacks. Replication functions and residual roughnesses are given for TiO(2), SiO(2), and Ta(2)O(5) materials produced by ion-assisted deposition and ion plating. Additional confirmation is given by measurements of scattering versus wavelength. The sensitivity of design to material and substrate effects is studied. At low-loss levels, surface and bulk phenomena are discussed together. Microstructure is characterized in the frequency bandwidth given by experiment.