<div>
	Influence of nano-sized horizontal inhomogeneities on surface profiling by means of XPS</div>

Denis S. Lukyantsev, Alexander V. Lubenchenko, Dmitriy A. Ivanov, Olga I. Lubenchenko, Alexandr Alexandr Fedotov

2022 , VOLUME 22, NUMBER 6 ( november-december )

ISSN 2226-1494 (print), ISSN 2500-0373 (online)

Publications

Editor-in-Chief

Nikiforov
Vladimir O.
D.Sc., Prof.

Partners

doi: 10.17586/2226-1494-2022-22-6-1104-1111

Influence of nano-sized horizontal inhomogeneities on surface profiling by means of XPS

D. S. Lukyantsev, A. V. Lubenchenko, D. A. Ivanov, O. I. Lubenchenko, A. A. Fedotov

Read the full article

Article in Russian

For citation:

Lukyantsev D.S., Lubenchenko A.V., Ivanov D.A., Lubenchenko O.I., Fedotov A.S. Influence of nano-sized horizontal inhomogeneities on surface profiling by means of XPS. Scientific and Technical Journal of Information Technologies, Mechanics and Optics, 2022, vol. 22, no. 6, pp. 1104–1111 (in Russian). doi: 10.17586/2226-1494-2022-22-6-1104-1111

Abstract

Quantitative analysis of thin films surface is performed by means of X-ray electron spectroscopy (XPS) according to a calculation model assuming surface layers of the target to be homogeneous and parallel. However, almost every surface of an ultra-thin film is rough. A study of such surface using the plane-parallel layer model will lead to incorrect results. This work proposes to use the model of inhomogeneous stochastic nano-structured surface layer for ultra-thin film profiling. Surface stochastic nano-structured inhomogeneities are described by the normal Gauss distribution function. To determine these inhomogeneities, three parameters are specified: dispersion (spread of thicknesses by the layer), mean and maximal thickness of the surface layer. For the first time, the type of X-ray photoelectron spectrum of an inhomogeneous stochastic nano-structured surface is found that is determined by functions of photoelectron production and transmission through that surface layer. The designed model is based on the following assumptions: photoelectrons are produced in substance and travel straight-forward (Straight Line Approximation) along the surface, photoelectron flux density decreases in the layer according to the Bouguer–Lambert law, photoelectrons of different energies lose energy differently, photoelectron energy losses in bulk and on surface differ. Modeling of X-ray photoelectron spectra of an oxidized metal film is performed using different models: homogeneous plane-parallel layers, an island nano-structured surface layer and an inhomogeneous stochastic nano-structured surface layer. Ranges of applicability of plane-parallel layer models and simple periodical nano-structured island surface layer for inhomogeneous stochastic nano-structured surface profiling are determined. The model of homogeneous plane-parallel layers shows satisfactory profiling results by some values of parameters of an inhomogeneous stochastic surface layer. It is shown that the model of a simple periodically nano-structured island layer leads to inadequate results by profiling of an inhomogeneous stochastic surface. The investigation shows that for more accurate profiling of an inhomogeneous ultra-thin film, it is necessary to consider inhomogeneity of a real surface, otherwise the calculated results would not match the true profile.

Keywords: phase profiling, horizontal inhomogeneities, surface roughness, nano-sized films, XPS

References

Tougaard S. Improved XPS analysis by visual inspection of the survey spectrum. Surface and Interface Analysis, 2018, vol. 50, no. 6, pp. 657–666. https://doi.org/10.1002/sia.6456
Lubenchenko A.V., Batrakov A.A., Pavolotsky A.B., Lubenchenko O.I., Ivanov D.A. XPS study of multilayer multicomponent films. Applied Surface Science, 2018, vol. 427, pp. 711–721. https://doi.org/10.1016/j.apsusc.2017.07.256
Lukiantsev D.S., Lubenchenko A.V., Ivanov D.A., Lubenchenko O.I., Pavolotsky A.B., Iachuk V.A., Pavlov O.N. The Formation of nanosuboxide layers in the oxide of niobium in low-power ion beam of argon. Proc. of the 3^rd International Youth Conference on Radio Electronics, Electrical and Power Engineering (REEPE), 2021, pp. 1–4. https://doi.org/10.1109/REEPE51337.2021.9388002
Lubenchenko A.V., Batrakov A.A., Shurkaeva I.V., Pavolotsky A.B., Krause S., Ivanov D.A., Lubenchenko O.I. XPS study of niobium and niobium-nitride nanofilms.Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques, 2018, vol. 12, no. 4, pp. 692–700. https://doi.org/10.1134/S1027451018040134
Lubenchenko A.V., Ivanov D.A., Lubenchenko O.I., Pavolotsky A.B., Lukiantsev D.S., Iachuk V.A., Pavlov O.N. Formation of inhomogeneous oxide and suboxide layers on an ultra-thin metal film by multiple oxidation and ion sputtering. Zhurnal tehnicheskoj fiziki, 2022, vol. 92, no. 8, pp. 1172–1178. (in Russian). https://doi.org/10.21883/JTF.2022.08.52779.68-22
Martín‐Concepción A.I., Yubero F., Espinós J.P., Tougaard S. Surface roughness and island formation effects in ARXPS quantification. Surface and Interface Analysis, 2004, vol. 36, no. 8, pp. 788–792. https://doi.org/10.1002/sia.1765
Varsányi G., Rée K., Mink G., Mohai M.Consideration of two dimensional surface roughnesses in quantitative XPS analysis. Periodica Polytechnica Chemical Engineering, 1987, vol. 31, no. 1-2, pp. 3–17.
Fadley C.S., Baird R.J., Siekhaus W., Novakov T., Bergström S.Å.L. Surface analysis and angular distributions in X-ray photoelectron spectroscopy. Journal of Electron Spectroscopy and Related Phenomena, 1974, vol. 4, no. 2, pp. 93–137. https://doi.org/10.1016/0368-2048(74)90001-2
Zemek J. Electron spectroscopy of corrugated solid surfaces. Analytical Sciences, 2010, vol. 26, no. 2, pp. 177–186. https://doi.org/10.2116/analsci.26.177
Kataev E., Wechsler D., Williams F.J., Köbl J., Tsud N., Franchi S., Steinrück H.-P., Lytken O. probing the roughness of porphyrin thin films with X‐ray photoelectron spectroscopy. ChemPhysChem, 2020, vol. 21, no. 20, pp. 2293–2300. https://doi.org/10.1002/cphc.202000568
Mohai M. XPS MultiQuant: multimodel XPS quantification software. Surface and Interface Analysis, 2004, vol. 36, no. 8, pp. 828–832. https://doi.org/10.1002/sia.1775
Mohai M. Calculation of layer thickness on rough surfaces by polyhedral model. Surface and Interface Analysis, 2008, vol. 40, no. 3‐4, pp. 710–713. https://doi.org/10.1002/sia.2751
Olejnik K., Zemek J., Werner W.S.M. Angular-resolved photoelectron spectroscopy of corrugated surfaces. Surface Science, 2005, vol. 595, no. 1-3, pp. 212–222. https://doi.org/10.1016/j.susc.2005.08.014
Leprince-Wang Y., Yu-Zhang K. Study of the growth morphology of TiO2 thin films by AFM and TEM. Surface and Coatings Technology, 2001, vol. 140, no. 2, pp. 155–160. https://doi.org/10.1016/S0257-8972(01)01029-5
Wu O.K.T., Peterson G.G., LaRocca W.J., Butler E.M. ESCA signal intensity dependence on surface area (roughness). Applications of Surface Science, 1982, vol. 11-12, pp. 118–130. https://doi.org/10.1016/0378-5963(82)90058-7
Lubenchenko A.V., Ivanov D.A., Lubenchenko O.I., Ivanova I.V. Formation of inelastic scattered background photoelectrons, X-ray photoelectron spectroscopy from multilayer inhomogeneous surface. Journal of Physics: Conference Series, 2019, vol. 1370, no. 1, pp. 012049. https://doi.org/10.1088/1742-6596/1370/1/012049
Lubenchenko A.V., Ivanov D.A., Lubenchenko O.I., Yachuk V.A., Pavlov O.N., Lashkov I.A., Lukyantsev D.S. Non-destructive chemical and phase layer profiling of multicomponent multilayer thin ultrathin films. Journal of Physics: Conference Series, 2019, vol. 1370, no. 1, pp. 012048. https://doi.org/10.1088/1742-6596/1370/1/012048

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License