Variable angle of incidence spectroscopic ellipsometry: Application to GaAs-AlxGa1−xAs multiple heterostructures

Abstract

The sensitivity of spectroscopic ellipsometry data to multilayer model parameters is shown to be a strong function of the angle of incidence. A quantitative study of sensitivity versus angle of incidence is performed for a GaAs‐Al_xGa_1−xAs‐GaAs substrate structure, showing that maximum sensitivity to layer thicknesses and AlGaAs composition occurs near the wavelength‐dependent principal angle. These results are verified by experimental measurements on two molecular‐beam epitaxy grown samples. New spectral features, not found in previous ellipsometry studies of similar structures, are also reported.