Investigation of the use of rotating linearly polarized light for characterizing SiO2 thin-film on Si substrate

This research is based on the Fresnel´s equations and the ellipsometric technique that investigate the sample of SiO₂ thin-film on Si substrate. The investigation is made by a probing beam which is in the form of a rotating linearly polarized light generated by the polarizing Mach-Zehnder interferometer (pMZi). The detection of the changed polarization states of the incident light due to reflection on the sample surfaces led to a set of unique characteristics describing a thin-film substrate system in terms of ellipsometric parameters ψ and Δ. SiO₂ thin-films were chosen to study because of their well known characteristics. The accuracy of measurements was confirmed by comparisons to calculated values derived from Fresnel´s equations and a standard instrument. The results clearly reveal a feasibility of using the rotating linearly polarized light produced by pMZi for a non-destructive characterization of the thin-film system.