rodriguez_de_marcos_2016
========================

L\. V\. Rodríguez\-de Marcos, J\. I\. Larruquert, J\. A\. Méndez and J\. A\. Aznárez, "Self\-consistent optical constants of SiO2 and Ta2O5 films", Opt\. Mater\. Express 6, 3622 \(2016\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/rodriguez_de_marcos_2016.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1364/ome\.6\.003622 <https://doi.org/10.1364/ome.6.003622>`__

**Source kind:** measurement

**Recorded technique:** Films by reactive electron\-beam evaporation in O2 \(1e\-2 Pa; base pressure 8e\-7 Pa for SiO2 after a ~420 K bake\) onto substrates heated to 573 K, cooled at ~1 K/min\: SiO2 56 nm \(0\.43 nm/s; on c\-cut MgF2 for transmittance, on Si for ellipsometry\) and 125 nm \(1\.71 nm/s; on a Si wafer, for EUV reflectance\); Ta2O5 53 nm \(0\.44 nm/s\)\. Transmittance \(FUV\) and near\-normal \(5 deg\) reflectance \(FUV\-EUV\) with a grazing\-incidence toroidal\-grating monochromator and a windowless discharge lamp, 12\.5\-200 nm; a Lambda\-9 spectrophotometer, 190\-1500 nm; SOPRALAB GES5E ellipsometry, 190\-950 nm, at 76 and 77 deg \(SiO2\) and 63 deg \(Ta2O5\), fitted with one \(SiO2\) or three \(Ta2O5\) Lorentz oscillators\. The optical constants follow from an iterative double Kramers\-Kronig analysis \(reflectance\-phase and k\-n\), extended with CXRO \(Henke\) and Chantler data at short wavelengths and the Lorentz oscillators at long\. Density from the critical angle of grazing\-incidence X\-ray reflectometry \(Cu K\-alpha, 0\.154 nm\) \(pp\. 3624\-3625, 3632\)\.

**Materials in structured entries:** None recorded.

**Dataset quantities:** None recorded.

**Contents:** 0 datasets; 0 formulas.

Curation notes
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Journal pages 3622\-3637 are pdf pages 1\-16\. Identity checked against the first page\. The optical constants are in figures only \(Fig\. 5 SiO2, Fig\. 6 Ta2O5, n and k against wavelength on linear and log axes; Figs\. 7\-10 the measurements recomputed from them\)\: 'The optical constants are available upon request' \(p\. 3636\)\. No datasets\. The paper states the substrate temperature as 523 K in the abstract \(p\. 3622\) and 573 K in the text and conclusions \(pp\. 3623\-3624, 3636\)\: a discrepancy, kept as printed\.

DATA SOURCES BY RANGE \(text pp\. 3627\-3628 and Table 1, p\. 3629, read from the table image; the library's cells are garbled\)\: lambda \< 30 nm, reflectance and k of an opaque film from the CXRO \(Henke\) database, k extended to ~4e5 eV with Chantler et al\.'s data in the last iteration, using the X\-ray densities; 30\-115\.2 nm, measured reflectance \(reflectance\-phase KK\), k from iteration 1 then 3; 115\.2\-190 nm, k from transmittance \(Beer\-Lambert neglecting reflectance, then exact calculations; for Ta2O5 averaged with the KK k\), reflectance measured, then \(SiO2\) calculated from iteration 2; 190\-950 nm, the Lorentz\-oscillator fit to ellipsometry; lambda \> 950 nm, the oscillators extrapolated\. Four KK integrations in all \(R\-phi, k\-n, R\-phi, k\-n\), giving {n\_final, k\_final}\.

TEXT VALUES \(pp\. 3632\-3636\), for the record; the vocabulary has no quantity for mass density or sum\-rule numbers, so they are notes only\: \- Density from the X\-ray critical angle\: SiO2 2\.28 g/cm3, '85\.4% of its bulk density'; Ta2O5 7\.72 g/cm3, 93\.2 % of bulk\. \- f\-sum rule \(Eq\. 4\)\: high\-energy limit of n\_eff 30 \(SiO2\) and 186 \(Ta2O5\) electrons per molecule, 29\.96 and 184\.32 with the relativistic correction; the integral of the present k gives 29\.65 \(SiO2\) and 187\.19 \(Ta2O5\)\: deviations ~1\.0 % and \-1\.6 %\. \- Inertial sum rule \(Eqs\. 5\-6\)\: zeta = 6\.5e\-4 \(SiO2\) and 1\.4e\-5 \(Ta2O5\), against Shiles et al\.'s satisfactory limit 0\.005\. \- Windowed sum rules \(Eqs\. 7\-16; Figs\. 11\-12\)\: zeta within Shiles's limits over the spectrum scanned, except the E^2\-weighted rule \(Eq\. 14\) at high\-energy windows; n\_eff\(inf\) of the windowed f\-sum rule deviates by up to ~1\.1 % \(SiO2\) and 1\.9 % \(Ta2O5\) from 29\.96 and 184\.32, diverging at high energies \(attributed to the Chantler and power\-law extrapolations\)\. The Ta2O5 k in the transparent range is larger than expected \(p\. 3630\); its ellipsometry and transmittance could not be fitted by one model \(p\. 3631\)\.

MATERIALS\. SiO2 and Ta2O5 films \(Ta2O5 registered in this extraction\); MgF2 and Si are substrates only\.

**Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets
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No datasets are recorded.

Formulas
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No formulas are recorded.

Corrections
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No dataset errata are recorded in this source record.

Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register </register>` for the checks and decisions.