Abstract

When the film thickness is considered as a parameter, a system composed of a transparent film on an absorbing substrate (in a transparent ambient) is characterized by a range of principal angle ${\overline{\varphi }}_{min}⩽\overline{\varphi }⩽{\overline{\varphi }}_{max}$ over which the associated principal azimuth $\overline{\psi }$ varies between 0° and 90° (i.e., $0°⩽\overline{\psi }⩽90°$) and the reflection phase difference Δ assumes either one of the two values: +π/2 or −π/2. We determine the principal angle $\overline{\varphi }(d)$ and principal azimuth $\overline{\psi }(d)$ as functions of film thickness d for the vacuum-SiO₂-Si system at several wavelengths as a concrete example. When the film thickness exceeds a certain minimum value, more than one principal angle becomes possible, as can be predicted by a simple graphical construction. We apply the results to principal-angle ellipsometry (PAE) of film-substrate systems; the relationship between $\overline{\varphi }$ and $\overline{\psi }$ during film growth is particularly interesting.

© 1977 Optical Society of America

Ellipsometric function of a film–substrate system: Applications to the design of reflection-type optical devices and to ellipsometry*

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Polarizer–surface-analyzer null ellipsometry for film–substrate systems*

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Linear-to-circular polarization transformation upon reflection by a transparent thin film on a transparent substrate: analytical determination of principal angles and principal azimuths

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Contours of constant principal angle and constant principal azimuth in the complex ∊ plane

R. M. A. Azzam
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