Roughness measurements by spectroscopic ellipsometry

The surface roughnesses of fifteen well-characterized aluminum roughness standards were studied using spectroscopic ellipsometry in the spectral range from 300 to 650 nm at 70° angle of incidence. It was found that the measured ellipsometric parameters ψ and Δ qualitatively discriminated between the rms roughnesses of the specimens. The rms local surface slopes (tanβ) were also calculated from the measured ellipsometric parameters Δ and ψ using the theory of Ohlidal and Lukes. All the ellipsometric results were compared with those obtained from total integrated scattering measurements. Good qualitative agreement was found.