Abstract
We develop, and solve, the equations of multiple wavelength ellipsometry
for thin uniaxial non-absorbing films . We show that the values of the
thickness and the real refractive indices ( parallel and perpendicular to
the optical axis ) of the thin film, can be obtained by three measurements,
at three different wavelengths, of the phase difference (between the filmed
and bare substrate phase changes caused by reflection), provided that the
refractive indices of both the incident medium as well as the substrate are
significatively dispersive. We also show, in the case of a dispersive thin
film, how to determine the indices of refraction in terms of wavelength, up
to any desired accuracy, by making the appropriate number of measurements
of the phase difference at different wavelengths.
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