V. A. Shvets
Russian Academy of Sciences
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Featured researches published by V. A. Shvets.
Optics and Spectroscopy | 2004
V. A. Shvets; E. V. Spesivtsev; S. V. Rykhlitskii
The specific features of the operation of a static photometric scheme of an ellipsometer are considered. Different configurations (combinations of the azimuths of optical elements) are analyzed; formulas for the calculation of the ellipsometric parameters are obtained; and, for each configuration under consideration, ranges of the unambiguous determination of these parameters are ascertained. The effect of different imperfections on the measurement accuracy of the parameters Ψ and Δ is analyzed and the possibility of a correct consideration of these imperfections is demonstrated. Methods for determining the parameters of the phase-shifting elements of the optical path are proposed. The measurement errors of the ellipsometric parameters due to inaccurate specification of the phase shifts of the compensator and the turning prism, as well as the adjustment errors of the optical elements, are determined.
Optics and Spectroscopy | 2009
V. V. Atuchin; V. N. Kruchinin; A. V. Kalinkin; V. Sh. Aliev; S. V. Rykhlitskiĭ; V. A. Shvets; E. V. Spesivtsev
Optical characteristics of the HfO2 − xNx and TiO2 − xNx films obtained by reactive ion beam sputtering have been investigated by spectral ellipsometry. The chemical composition of the films was determined using X-ray photoelectron spectroscopy. The nitrogen content in the oxynitride films (determined by the N2/O2 ratio in the gas mixture during synthesis) reached ≈9 at % for TiO2 − xNx and ≈ 6 at % for HfO2 − xNx. It is found that the dispersion relations n(λ) and k(λ) for the TiO2 − xNx films change from those characteristic of titanium dioxide to those typical of titanium nitride with an increase in the nitrogen content from 0 to ≈9 at %. The optical parameters of the HfO2 − xNx films depend weakly on the nitrogen content in the range 0–6 at %.
Optics and Spectroscopy | 2017
V. A. Shvets; V. N. Kruchinin; V. A. Gritsenko
A brief review of the optical properties of oxide materials that are used at present as dielectrics in modern microelectronics is presented. Using spectral ellipsometry, dispersion dependencies for different materials are measured. A brief comparative analysis of different dielectric coatings is carried out. The results of our research will be useful in further studies of the properties of dielectrics, as well as in technologies that are employed in the development of new semiconductor instruments and devices.
Optics and Spectroscopy | 2009
V. A. Shvets
The determination accuracy of the parameters of multilayer structures during their in situ ellipsometric monitoring is analyzed. A qualitative criterion is proposed that makes it possible to evaluate the validity of replacement of the multilayer structure by a certain medium with effective optical constants. According to this criterion, this replacement is possible if the complex reflection coefficients Rp, s of the structure satisfy the relation (Rp/Rs + cos2φ)/(Rs + Rpcos2φ) = 1, where φ is the angle of incidence of light. It is shown that, for structures consisting of layers with a high refractive index, this condition is implemented with a high accuracy. This proves that, upon the successive solution of the ellipsometry problem for layers of this structure, errors are not accumulated. In particular, this inference can be applied to structures based on a cadmium-mercury-tellurium ternary compound.
Optics and Spectroscopy | 2009
V. V. Atuchin; V. N. Kruchinin; A. V. Kalinkin; V. Sh. Aliev; S. V. Rykhlitskiĭ; V. A. Shvets; E. V. Spesivtsev
Optical characteristics of the HfO2 − xNx and TiO2 − xNx films obtained by reactive ion beam sputtering have been investigated by spectral ellipsometry. The chemical composition of the films was determined using X-ray photoelectron spectroscopy. The nitrogen content in the oxynitride films (determined by the N2/O2 ratio in the gas mixture during synthesis) reached ≈9 at % for TiO2 − xNx and ≈ 6 at % for HfO2 − xNx. It is found that the dispersion relations n(λ) and k(λ) for the TiO2 − xNx films change from those characteristic of titanium dioxide to those typical of titanium nitride with an increase in the nitrogen content from 0 to ≈9 at %. The optical parameters of the HfO2 − xNx films depend weakly on the nitrogen content in the range 0–6 at %.
Optics and Spectroscopy | 2010
V. A. Shvets
The problem of analysis and processing of data of in situ ellipsometric measurements obtained in the process of growth of layers on multilayer optically inhomogeneous structures is considered. It is shown that the experimental data allow one to determine, for an arbitrary structure, all its reflective properties described by the complex reflection coefficients Rp and Rs or, alternatively, by a pair of other complex quantities, namely, by the ellipsometric parameter ρ and parameter ϕ characterizing uniformity of the structure. A numerical algorithm is proposed that is applicable to an arbitrary number of experimental points, which allows one to reduce the problem of optimization to a search for a single complex quantity. Numerical simulation performed using this algorithm demonstrates good convergence and stability to both random errors of the measurements and systematic errors.
Optics and Spectroscopy | 2017
V. A. Shvets
A method for measuring the phase of the reflection coefficient in the optical wavelength range is proposed. The method is simple in experimental implementation and is based on measuring the energyreflection coefficients of a sample in two media with different refractive indices. Analytical and numerical estimates show that the measurement accuracy of the phase is on the order of 1°. The possibilities of using the results of the phase measurement in practice for a more complete characterization of materials and structures under investigation are considered.
Optics and Spectroscopy | 2016
V. A. Shvets
Differential equations that describe the reflection of polarized light from an optically inhomogeneous medium are considered. In the approximation of small variations of the refractive index, analytical expressions for the reflection coefficients are obtained for both types of polarization for the exponential and harmonic profiles of the optical constants. The accuracy of the obtained expressions is estimated by numerical simulation. It is found that analytical formulas describe well the behavior of the ellipsometric parameters of periodic structures based on Hg1–xCdxTe with a sinusoidal profile of the refractive index.
Optics and Spectroscopy | 2015
V. A. Shvets; V. N. Kruchinin; S. V. Rykhlitskii; V. Yu. Prokop’ev; N. F. Uvarov
An ellipsometric in situ study of the growth of porous aluminum anodic oxide films on aluminum substrate has been performed. Theoretical calculations have been carried out to interpret the experimental dependences of ellipsometric parameters; they made it possible to identify the most characteristic details of anodic oxidation. It is shown that the ellipsometric method allows one to control in situ in real time a number of important layer parameters: growth rate, porosity, depth uniformity, and the state of interface. The ellipsometric measurements have also revealed high sensitivity to the presence of metal nanoparticles both in the bulk of a layer and on its surface.
Optics and Spectroscopy | 2009
Victor V. Atuchin; V. N. Kruchinin; A. V. Kalinkin; V. Sh. Aliev; S. V. Rykhlitskiĭ; V. A. Shvets; E. V. Spesivtsev
Optical characteristics of the HfO2 − xNx and TiO2 − xNx films obtained by reactive ion beam sputtering have been investigated by spectral ellipsometry. The chemical composition of the films was determined using X-ray photoelectron spectroscopy. The nitrogen content in the oxynitride films (determined by the N2/O2 ratio in the gas mixture during synthesis) reached ≈9 at % for TiO2 − xNx and ≈ 6 at % for HfO2 − xNx. It is found that the dispersion relations n(λ) and k(λ) for the TiO2 − xNx films change from those characteristic of titanium dioxide to those typical of titanium nitride with an increase in the nitrogen content from 0 to ≈9 at %. The optical parameters of the HfO2 − xNx films depend weakly on the nitrogen content in the range 0–6 at %.