HIGH-PRECISION UV-VISIBLE NEAR-IR STOKES VECTOR SPECTROSCOPY

An ellipsometer utilizing the polarizer-sample-retarder-rotating analyser configuration measures all four elements of the Stokes vector. Consequently the ellipsometric parameters PSI and DELTA as well as the polarization transfer factor D of the sample can be measured simultaneously as a function of the photon energy E. The measurement of all four elements of the Stokes vector is shown to be well suited for the ellipsometric characterization of non-ideal samples, e.g. laterally inhomogeneous or rough samples, and it may be used to improve the precision of high lateral resolution (''microspot'') measurements. Formulae for the error spectra deltaPSI(E), deltaDELTA(E), and deltaD(E) were derived by analysing the influence of the random errors of the measurement. These error spectra provide the weights in minimization procedures for the determination of the geometrical and strutural sample parameters and result, via the analysis of the hessian matrix, in the errors of the sample parameters adjusted to the spectra. The effect of systematic alignment errors is discussed and fast Kramers-Kronig-consistent spectral inversion is shown to be a useful tool for the reduction of systematic model errors.