Novel Wide-Angle Ellipsometric Arrangement for Thin Film Thickness Measurement

A parabolic mirror is used for the first time in a wide-angle ellipsometric system to determine the parameters psi and Delta and the thickness of SiO2 layer naturally grown on Si crystal substrate. Collimated illuminating beam of diameter 20 mm incident on a parabolic mirror is reflected at the Si-SiO2 system to provide wide angle of incidence. The polarization states of points in the illuminated area are determined and the data is analyzed for real-time thickness maps over the measured area of the surface. The thickness of SiO2 layer is found as 3.02 nm with Standard deviation +/- 0.12 nm. Null ellipsometer is also used at different angles of incidence to check our result and nearly the same thickness value was obtained.