An error evaluation technique for the angle of incidence in a rotating element ellipsometer using a quartz crystal

The error in the angle of incidence for a rotating element ellipsometer is evaluated using a uniaxial quartz crystal. At a fixed angle of incidence with respect to the surface of reflection, the ratio of reflectance in the parallel to that in the perpendicular electromagnetic field is measured by rotating the quartz crystal through a full cycle. We determine the deviation in the angle of incidence by comparing the experimentally measured reflectance ratio to its calculated value.