Generalized ellipsometry for materials characterization

Abstract Ellipsometry experiments normally measure two to four parameters, which are converted to the ellipsometric parameters ψ and Δ. This is usually sufficient for many samples, but more complicated situations (such as anisotropic or depolarizing samples) require more sophisticated measurements. Over the last 7 years, we have developed the two-modulator generalized ellipsometer (2-MGE), which measures eight elements of the sample Mueller matrix simultaneously either in reflection or transmission. In reflection, the 2-MGE totally characterizes light reflection from anisotropic samples, measuring the normal ellipsometry parameters, as well as the cross-polarization and depolarization effects. Applications include the determination of the spectroscopic optical functions of uniaxial materials (such as TiO2 and ZnO), and the measurement of cross-polarization from diffractive structures. In transmission, the 2-MGE completely characterizes a general linear diattenuator and retarder. Applications include the measurement of the retardation and diattenuation of film polarizers and internal electric fields in LiNbO3 and CdZnTe under bias.