Spectroscopic ellipsometry characterization of HfxSiyOz films using the Cody–Lorentz parameterized model
| Autor: | T. Rhoad, Alain C. Diebold, P. Y. Hung, Brendan Foran, J. Price |
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| Rok vydání: | 2004 |
| Předmět: |
Kramers–Kronig relations
Materials science Physics and Astronomy (miscellaneous) Transmission electron microscopy Ellipsometry Band gap Analytical chemistry Sensitivity (control systems) Absorption (electromagnetic radiation) Molecular physics Characterization (materials science) Exponential function |
| Zdroj: | Applied Physics Letters. 85:1701-1703 |
| ISSN: | 1077-3118 0003-6951 |
| DOI: | 10.1063/1.1784889 |
| Popis: | A parameterized, Kramers–Kronig consistent, Cody–Lorentz optical model is used to simulate the dielectric response of thin HfxSiyOz films. Optical constants are determined in the range 0.75–8.35eV. The Cody–Lorentz model has three specific differences when compared to the previously employed Tauc–Lorentz model: (1) weak exponential absorption below the band gap, (2) a modified joint density-of-states, and (3) a restriction on the e1(∞) parameter. These three differences allow the Cody–Lorentz model to have an improved fit to experimental data. As a result of a more accurate optical model for HfxSiyOz, we were able to identify an interfacial layer with thickness in close agreement with transmission electron microscopy measurements. Use of the Tauc–Lorentz model when fitting the same experimental data could not identify an interfacial layer. Results are also discussed in which the Cody–Lorentz model shows sensitivity to varying degrees of silicate composition. |
| Databáze: | OpenAIRE |
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