Abstract

A new polarization modulation ellipsometer has been designed and constructed where both polarizations of the exit beam are detected and analyzed. Light from a monochromator passes through a polarizer and photoelastic modulator (driven ~50 kHz), reflects off the sample, and then passes through a Wollaston prism, which acts as the analyzer. Both exit beams are individually detected with either photodiodes or phototubes and analyzed using digital voltmeters to determine the de component and two lock-in amplifiers to determine the fundamental and first harmonic. By setting the (polarizer-modulator) angle to ±45° and modulator and analyzer angles to ±22.5 or ±67.5°, all the associated ellipsometric parameters (N= cos2ψ; S = sin2 ψ sinΔ) can be measured allowing for determination of the ellipsometric angles ψ and Δ as well as β = N² + S² + C², which is a measure of the surface depolarization.

© 1988 Optical Society of America