Abstract

The conventional formula for the ellipsometric ratio ρ = r_p/r_s diverges in the limit when the dielectric constants on either side of an inhomogeneous layer become equal, ∊₁ = ∊₂. The general case, including ∊₁ = ∊₂, necessitates going to second order in the layer thickness. A formula is derived that includes the ∊₁ = ∊₂ case without divergence; the predicted maximum in the imaginary part of ρ when ∊₁ ≈ ∊₂ indicates that index matching (of the bounding media) can significantly increase the ellipsometric signal.

© 1988 Optical Society of America

Ellipsometry of surface films on a uniform layer

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