Optical models for ultrathin oxides on Si- and C-terminated faces of thermally oxidized SiC

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Abstract

The thickness, refractive index, density, and interface properties of thin thermal oxides on both Si- and C-terminated 4H-SiC faces were investigated by ellipsometry using optical models of increasing complexity. We used different parametrizations of the dielectric function, a transition layer, and also investigated the multisample approach. The thickness of the transition layer increases with decreasing oxide thickness below the layer thickness of about 30 nm, it correlates with the surface roughness measured by atomic force microscopy, and it was found to be significantly larger for the C-terminated than that for the Si-terminated face. For oxide layer thicknesses larger than 30 nm, the refractive index of the bulk oxide layer is the same as that of thermal SiO2 on Si. We found an apparent decrease in mass density (as well as optical density) with decreasing oxide thickness using a combination of ellipsometry and backscattering spectrometry, which can be explained by the surface roughness, depending on the layer thickness revealed by atomic force microscopy.

Original languageEnglish
Article number123506
JournalJournal of Applied Physics
Volume106
Issue number12
DOIs
Publication statusPublished - 2009

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oxides
transition layers
ellipsometry
surface roughness
atomic force microscopy
refractivity
optical density
backscattering
spectroscopy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

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title = "Optical models for ultrathin oxides on Si- and C-terminated faces of thermally oxidized SiC",
abstract = "The thickness, refractive index, density, and interface properties of thin thermal oxides on both Si- and C-terminated 4H-SiC faces were investigated by ellipsometry using optical models of increasing complexity. We used different parametrizations of the dielectric function, a transition layer, and also investigated the multisample approach. The thickness of the transition layer increases with decreasing oxide thickness below the layer thickness of about 30 nm, it correlates with the surface roughness measured by atomic force microscopy, and it was found to be significantly larger for the C-terminated than that for the Si-terminated face. For oxide layer thicknesses larger than 30 nm, the refractive index of the bulk oxide layer is the same as that of thermal SiO2 on Si. We found an apparent decrease in mass density (as well as optical density) with decreasing oxide thickness using a combination of ellipsometry and backscattering spectrometry, which can be explained by the surface roughness, depending on the layer thickness revealed by atomic force microscopy.",
author = "P. Petrik and E. Szil{\'a}gyi and T. Lohner and G. Battistig and M. Fried and Gergely Dobrik and L. B{\'i}r{\'o}",
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T1 - Optical models for ultrathin oxides on Si- and C-terminated faces of thermally oxidized SiC

AU - Petrik, P.

AU - Szilágyi, E.

AU - Lohner, T.

AU - Battistig, G.

AU - Fried, M.

AU - Dobrik, Gergely

AU - Bíró, L.

PY - 2009

Y1 - 2009

N2 - The thickness, refractive index, density, and interface properties of thin thermal oxides on both Si- and C-terminated 4H-SiC faces were investigated by ellipsometry using optical models of increasing complexity. We used different parametrizations of the dielectric function, a transition layer, and also investigated the multisample approach. The thickness of the transition layer increases with decreasing oxide thickness below the layer thickness of about 30 nm, it correlates with the surface roughness measured by atomic force microscopy, and it was found to be significantly larger for the C-terminated than that for the Si-terminated face. For oxide layer thicknesses larger than 30 nm, the refractive index of the bulk oxide layer is the same as that of thermal SiO2 on Si. We found an apparent decrease in mass density (as well as optical density) with decreasing oxide thickness using a combination of ellipsometry and backscattering spectrometry, which can be explained by the surface roughness, depending on the layer thickness revealed by atomic force microscopy.

AB - The thickness, refractive index, density, and interface properties of thin thermal oxides on both Si- and C-terminated 4H-SiC faces were investigated by ellipsometry using optical models of increasing complexity. We used different parametrizations of the dielectric function, a transition layer, and also investigated the multisample approach. The thickness of the transition layer increases with decreasing oxide thickness below the layer thickness of about 30 nm, it correlates with the surface roughness measured by atomic force microscopy, and it was found to be significantly larger for the C-terminated than that for the Si-terminated face. For oxide layer thicknesses larger than 30 nm, the refractive index of the bulk oxide layer is the same as that of thermal SiO2 on Si. We found an apparent decrease in mass density (as well as optical density) with decreasing oxide thickness using a combination of ellipsometry and backscattering spectrometry, which can be explained by the surface roughness, depending on the layer thickness revealed by atomic force microscopy.

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