SOURCES OF ERROR IN ELLIPSOMETRY

In ellipsometric studies the analysis of an elliptically polarized light beam is accurately performed by reducing the elliptical vibration to a linear one and measuring the azimuth of the latter vibration. The change from an elliptical to a linear vibration is effected by a quarter-wave plate suitably oriented. The azimuth may be detected by electronic methods which require modulation of the light beam. Errors are introduced by (1) incorrect settings of the polarizer, analyzer, and quarter-wave plate, (2) the quarter-wave plate not introducing a phase shift of exactly 90°, (3) parasitic birefringence in the electro-optic components. These errors are discussed together with sensitivity, precision and accuracy when photoelectric detection is used. © 1969.