Systematic-Errors in Rotating-Compensator Ellipsometry

Systematic error sources for the rotating-compensator ellipsometer are discussed. Starting from a general formalism, we derive explicit first-order expressions for the errors deltaPSI and deltaDELTA caused by azimuthal errors and residual ellipticity introduced by imperfect polarizers or compensators and windows. Comparison is made with measurement results. It is shown that all azimuthal-angle errors can be eliminated by a two-zone measurement and that the natural optical rotation of the rotating quartz compensator has no effect on the measurements.