Optical characterization of HfO2 thin films

Franta, Daniel; Ohlı́dal, Ivan; Nečas, David; Vižd'a, František; Caha, Ondřej; Hasoň, Martin; Pokorný, Pavel

doi:10.1016/j.tsf.2011.03.128

Cited by 35 publications

(23 citation statements)

References 36 publications

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“…[40,77] where this specific shape absorption has been incorrectly associated with the exponential Urbach tail (as it was also previously noted by Franta et al [68]). Moreover, our results show a correlation between not only the energy band gap but also the bounded oscillators positions (E 0j ), obtained from the TLLG model, to other important material properties such as composition, phase structure, doping, stress, etc.…”

Section: Sub-bandgap Absorption Features In Hafnium Dioxide (Hfo 2 ) mentioning

confidence: 71%

“…However, the absorption below the band gap often does not correspond to the Urbach tail and the simple combination of Eq. (6) with the TL oscillator(s) is insufficient near E g [67,68]. In our approach, the imaginary part of dielectric function ε 2 includes not only the TL oscillator(s) with E 0j N E g (the band-gap parameter E g is set to be the same for all TL oscillators) but also an ensemble of free/unbounded Lorentz and/or Gaussian oscillators.…”

Section: Tauc-lorentz-lorentz-gaussian (Tllg) Modelmentioning

confidence: 99%

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Modified Tauc–Lorentz dispersion model leading to a more accurate representation of absorption features below the bandgap

2015

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Section: Sub-bandgap Absorption Features In Hafnium Dioxide (Hfo 2 ) mentioning

confidence: 71%

Section: Tauc-lorentz-lorentz-gaussian (Tllg) Modelmentioning

confidence: 99%

Modified Tauc–Lorentz dispersion model leading to a more accurate representation of absorption features below the bandgap

2015

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“…The optical constants of the overlayer were modeled again using a PJDOS model consisting only of a single interband contribution with corresponding dispersion parameters. The PJDOS dispersion model was chosen because it is mathematically simpler than, for instance, the widely used Tauc–Lorentz model, its parameters have clear physical meaning and it can describe well the dielectric response of amorphous materials …”

Section: Modeling and Data Processingmentioning

confidence: 99%

Ellipsometric characterization of inhomogeneous non‐stoichiometric silicon nitride films

Nečas

Franta

Ohlı́dal

et al. 2013

Surface & Interface Analysis

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Variable-angle spectroscopic ellipsometry is employed for the optical characterization of non-stoichiometric silicon nitride thin films exhibiting inhomogeneity formed by refractive index and extinction index changes through the film thickness. For all the film samples, the best fit of the experimental data is achieved if, in addition to the inhomogeneity, an overlayer or roughness of the upper boundary is included. However, distinguishing of these two defects is found not to be possible. The influence of working gas ratio, deposition temperature and on/off time on the film properties is studied. The refractive index and extinction coefficient is found to increase with increasing working gas ratio and less significantly with decreasing deposition temperature. It is also found that the inhomogeneity increases with decreasing deposition temperature, and the deposition rate of the films decreases with increasing working gas ratio. The influence of the on/off time on the film properties is practically unimportant.

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“…Various optical applications of HfO 2 thin films have been pursued such as, for example, chirped mirrors and band pass filters, UV mirrors with a high damage threshold, and heat mirrors for energy efficient windows. As a result of the high transparency, hafnia thin films can be used as antireflective coatings for night vision devices, IR optical devices, and in cameras used for space applications [3][4][5][6]13,14]. The band gap of HfO 2 is ca.…”

Section: Introductionmentioning

confidence: 99%

Characterization of HfO2 Optical Coatings Deposited by MF Magnetron Sputtering

et al. 2019

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The aim of this work is to determine the influence of medium frequency magnetron sputtering powers on the various properties of hafnium dioxide (HfO2) thin films. Microstructure observations show that an increase in the sputtering power has a significant influence on HfO2 films’ microstructure. As-deposited hafnia thin films exhibit nanocrystalline structure with a monoclinic phase, however thr rise of the sputtering power results in an increase of crystallite sizes. Atomic force microscopy investigations show that the surface of the deposited films is smooth, crack-free, and composed of visible grains. The surface roughness and the value of the water contact angle increase with the increase of the sputtering power. Measurements of the optical properties show that HfO2 coatings are transparent in the visible wavelength range. A higher sputtering power causes a decrease of an average transmittance level and a simultaneous increase of the real part of the refractive index. Nanoindentation measurements reveal that the thin film hardness and Young’s elastic modulus increase with an increase in the sputtering power. Moreover, the results of plasticity index H/E and plastic resistance parameter H3/E2 are discussed. Based on the obtained results, a correlation between the sputtering power and the structural, surface, and optical properties, as well as the hardness and Young’s elastic modulus, were determined.

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Optical characterization of HfO2 thin films

Cited by 35 publications

References 36 publications

Modified Tauc–Lorentz dispersion model leading to a more accurate representation of absorption features below the bandgap

Modified Tauc–Lorentz dispersion model leading to a more accurate representation of absorption features below the bandgap

Ellipsometric characterization of inhomogeneous non‐stoichiometric silicon nitride films

Characterization of HfO2 Optical Coatings Deposited by MF Magnetron Sputtering

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