The possibilities of multi-angle spectrophotometry for determining the parameters of films on single-layer structures

Single-layer Ta-Si-C-N films on fused quartz substrates were made by direct current magnetron sputtering. The structural perfection of the film was investigated by X-ray diffraction analysis, scanning electron microscopy and optical emission spectroscopy of glow discharge. The optical parameters of the films were determined by the method of multi-angle spectrophotometry. Spectral dependences of the transmission coefficients of substrates and structures at normal light incidence in the wavelength range of 200—2500 nm are obtained. It is shown that the transmission spectrum of the sample has an oscillating character, which is caused by interference phenomena characteristic of layered structures. Spectral dependences of the reflection coefficients of films and substrates in the wavelength range of 200—2500 nm at small angles of incidence of light are obtained. By the magnitude of the difference between the reflection coefficient at the maximum of the interference of the film and the corresponding reflection coefficient of the substrate at the same wavelength, it is shown that the absorption in the film is low. A formula is obtained for determining the absorption coefficient of a film from the measured parameters. Based on the experimental data obtained, spectral dependences of the absorption coefficients of the substrate, structure and film are constructed. The method of reflection at two angles of incidence, based on the determination of the position of the interference extremes on the spectral dependences of the reflection coefficients, calculated discrete values of the refractive coefficients in the wavelength range 400—1200 nm. The obtained values are approximated by the Cauchy equation. The film thickness was calculated, which was d = 1046 nm ± 13%. Spectral dependences of the film attenuation indices with and without reflection are constructed. A summary table is presented with the obtained values of the refractive coefficients and absorption indices with and without reflection.

1. Kondrashin V.I. Determination of SnO2 thin optically transparent films’ thickness by the envelope method. University Proceedings. Volga Region. Engineering Sciences. 2016; 38(2): 93—101. (In Russ.). https://izvuz_tn.pnzgu.ru/tn8216

2. Usanov D.A., Skripal Al.V., Skripal An.V., Abramov A.V., Bogolyubov A.S., Bakui A. Measurement of parameters of nanometer films by optical and radio wave methods. Izvestiya vysshikh uchebnykh zavedeniy. Elektronika = Proceedings of Universities. Electronics. 2010; 83(3(83)): 44—50. (In Russ.). https://elibrary.ru/mngzfd

3. Kiselev D.A., Zhukov R.N., Bykov A.S., Malinkovich M.D., Parkhomenko Yu.N., Vygovskaya E.A. Initiation of polarized state in lithium niobate thin films synthesized on isolated silicon substrates. Izvestiya vysshikh uchebnykh zavedenii. Materialy elektronnoi tekhniki = Materials of Electronics Engineering. 2012; (2): 25—29. (In Russ.). https://doi.org/10.17073/1609-3577-2012-2-25-29

4. Zhuravleva P.L., Shchur P.A., Melnikov A.A. Study of the structural parameters of thin films by analytical methods. Trudy VIAM. 2019; 78(6): 104—113. https://dx.doi.org/10.18577/2307-6046-2019-0-6-104-113

5. Shayapov V.R. An integrated approach to the determination of the physical properties of thin films. In: Third interdisciplinary youth scientific forum with international participation “New Materials”. Moscow; 2017. 386 p. (In Russ). https://elibrary.ru/xnvfyt

6. Brus V.V., Kovalyuk Z.D., Maryanchuk P.D. Optical properties of TiO2–MnO2 thin films fabricated by electron-beam evaporation. Zhurnal tekhnicheskoy fiziki. 2012; 82(8): 110—113. (In Russ). https://journals.ioffe.ru/articles/viewPDF/10683

7. Bobrovnikov Yu.A., Kozar’ A.V., Popov K.V., Tikhonov A.N., Tikhonravov A.V., Trubetskov M.K. Investigation of the inhomogeneity of thin films by spectrophotometric methods. Vestnik Moskovskogo universiteta. Seriya 3. Fizika, Astronomiya. 1997; (4): 24—27. (In Russ.). http://vmu.phys.msu.ru/file/1997/4/97-4-24.pdf

8. Sokolov V.I., Marusin N.V., Panchenko V.Ya., Savelyev A.G., Seminogov V.N., Khaidukov E.V. Determination of refractive index, extinction coefficient and thickness of thin films by the method of waveguide mode excitation. Kvantovaya elektronika. 2013; 43(12): 1149—1153. (In Russ.). http://www.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=qe&paperid=15272&option_lang=eng

9. Vanyukhin K.D., Zakharchenko R.V., Kargin N.I., Seidman L.A. Peculiarity of forming transparent conducting films on basis of oxides indium-tin for contacts on GaN-based light emitting diodes. Izvestiya vysshikh uchebnykh zavedenii. Materialy elektronnoi tekhniki = Materials of Electronics Engineering. 2013; (2): 60—64. (In Russ.). https://doi.org/10.17073/1609-3577-2013-2-60-64

10. Abgaryan K.K., Bazhanov D.I., Mutigullin I.V. Theoretical investigation of electronic and structural properties of AlN thin films. Izvestiya vysshikh uchebnykh zavedenii. Materialy elektronnoi tekhniki = Materials of Electronics Engineering. 2015; 18(1): 48—51. (In Russ.). https://doi.org/10.17073/1609-3577-2015-1-48-51

11. Khomchenko A.V., Sotsky A.B., Romanenko A.A., Glazunov E.V., Shulga A.V. Waveguide method for measuring the parameters of thin films. Zhurnal tekhnicheskoy fiziki. 2005; 75(6): 98—106. (In Russ.). https://journals.ioffe.ru/articles/viewPDF/8584

12. Sakhbiev T.R. Two-frequency methods for determining the thickness and dielectric parameters of thin films. Novoye slovo v nauke: perspektivy razvitiya. 2015; 4(6): 171–172. (In Russ.). https://elibrary.ru/xxxsbv

13. Tikhonravov A.V., Trubetskov M.K., Amotchkina T.V., DeBell G., Pervak V., Krasilnikova-Sytchkova A., Grilli M.L., Ristau D. Optical parameters of oxide films typically used in optical coating production. Applied Optics. 2011; 50(9): C75—C85. https://doi.org/10.1364/AO.50.000C75

14. Tikhonravov A.V., Amotchkina T.V., Trubetskov M.K., Francis R.J., Janicki V., Sancho-Parramon J., Zorc H., Pervak V. Optical characterization and reverse engineering based on multiangle spectroscopy. Applied Optics. 2012; 51(2): 245—254. https://doi.org/10.1364/AO.51.000245

15. Ayupov B.M., Zarubin I.A., Labusov V.A., Sulyaeva V.S., Shayapov V.R. Searching for the starting approximation when solving inverse problems in ellipsometry and spectrophotometry. Journal of Optical Technology. 2011; 78(6): 350—354. https://doi.org/10.1364/jot.78.000350

16. Shmidt V. Optical spectroscopy for chemists and biologists. Moscow: Tekhnosfera; 2007. 362 p. (In Russ.)

17. Klark E.R., Eberkhardt K.N. Microscopic methods for studying materials. Moscow: Tekhnosfera; 2007. 376 p. (In Russ.)

18. Bokker U. Spectroscopy. Moscow: Tekhnosfera; 2009. 528 p. (In Russ.)

19. Landsberg G.S. Optics: textbook for universities. Moscow: Fizmalit; 2006. 848 p. (In Russ.)

20. Konstantinova A.F., Grechushnikov B.N., Bokut B.V., Valyashko E.G. Optical properties of crystals. Minsk: Navuka i tekhnika; 1995. 303 p. (In Russ.)

21. Tolmachev G.N., Kovtun A.P., Pavlenko A.V., Zakharchenko I.N., Aliev I.M., Reznichenko L.A., Verbenko I.A. Synthesis, structure, and optical characteristics of barium-strontium niobate thin films. Physics of the Solid State. 2015; 57(10): 2106—2111. https://doi.org/10.1134/S1063783415100339

22. Ayupov B.M., Rumyantsev Yu.M., Shayapov V.R. Particular features of determination of the thickness of dielectric films obtained in researches. Poverkhnost’. rentgenovskiye, sinkhrotronnyye i neytronnyye issledovaniy. 2010; (5): 100—105. (In Russ.). https://elibrary.ru/msqeaj

23. Manifacier J.C., Gasiot J., Fillard J.P. А simple method for the determination of the optical constants n, h and the thickness of a weakly absorbing thin film. Journal of Physics E: Scientific Instruments. 1976; 9(11): 1002—1004. https://doi.org/10.1088/0022-3735/9/11/032

24. Swanepoel R. Determination of the thickness and optical constants of amorphous silicon. Journal of Physics E: Scientific Instruments. 1983; 16(12): 1214—1223. https://doi.org/10.1088/0022-3735/16/12/023

25. Kiryukhantsev-Korneev Ph.V., Sytchenko A.D., Sviridov T.A., Sidorenko D.A., Andreev N.V., Klechkovskay V.V., Polčak J., Levashov E.A. Effects of doping with Zr and Hf on the structure and properties of Mo-Si-B coatings obtained by magnetron sputtering of composite targets. Surface and Coatings Technology. 2022: 128141. https://doi.org/10.1016/j.surfcoat.2022.128141

26. Born M., Vol’f E. Fundamentals of optics. Moscow: Nauka; 1970. 855 p. (In Russ.)

27. Karamaliyev R.A., Qajar C.O. Optical properties of composite thin films containing silver nanoparticles. Journal of Applied Spectroscopy. 2012; 79(3): 404—409. https://doi.org/10.1007/s10812-012-9615-1

28. Shalimova K.V. Physics of semiconductors. Moscow: Energiya; 1971. 400 p. (In Russ.)

29. Efimov A.M. Optical properties of materials and mechanisms of their formation: textbook. Saint Petersburg: SPbGUITMO; 2008. 103 p. (In Russ.)

30. Bohren C.F., Huffman D.R. Absorption and scattering of light by small particles. John Wiley & Sons, Inc.; 1983. 545 p.