REFLECTION-TRANSMISSION PHOTOELLIPSOMETRY - THEORY AND EXPERIMENTS

We propose a method that uses reflection and transmission photoellipsometry to analyze samples consisting of thin films combined with semitransparent thick layers or substrates in the form of multilayer structures. A thick film or substrate is defined as a layer for which no interference effects can be observed for a given wavelength resolution, and contributions from multiple reflections in the substrate are taken into account in the theoretical treatment. An automatic reflection-transmission spectroscopic ellipsometer was built to test the theory, and satisfactory results have been obtained. Examples corresponding to a strongly absorbing film deposited on a glass substrate and a highly transmitting film also deposited on glass are shown. In both cases a good fit between theory and experiment is found. The photoellipsometric method presented is particularly suited to the analysis of actual samples of energy-efficient coatings for windows.