Thickness Calculations for a Transparent Film from Ellipsometric Measurements*

Plotting of ellipsometric functions can be avoided when the index of refraction of the film is known and when only thickness is to be determined. The ellipsometric equations can be simplified by assuming an angle of incidence equal to Brewster’s angle for the air-film interface. The simplification leads to a precise expression for thickness in terms of Δ and ψ and some parameters, which depend on the index and can be collected in computed tables.