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Variable Angle of Incidence Spectroscopic Ellipsometric Study of Semiconductor Multilayer Structures

Published online by Cambridge University Press:  25 February 2011

Paul G. Snyder
Affiliation:
University of Nebraska-Lincoln, Lincoln, NE 68588-0511
John A. Woollam
Affiliation:
University of Nebraska-Lincoln, Lincoln, NE 68588-0511
Samuel A. Alterovitz
Affiliation:
NASA Lewis Research Center, Cleveland, OH 44135
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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 for a GaAs-AlxGa1-xAs-GaAs structure shows that maximum sensitivity to layer thicknesses and ternary composition occurs near the wavelength-dependent principal angle. These results are verified by experimental measurements on two MBE-grown samples. Moderately high doping levels in the ternary layers are also found to strongly affect the data at photon energies below the ternary bandgap. Null ellipsometry measurements at only two wavelengths are sufficient to determine layer thicknesses.

Type
Articles
Copyright
Copyright © Materials Research Society 1986

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References

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