RU2343118C1 - Composition for obtaining thin film based on system of double zirconium and germanium oxides - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: composition for obtaining thin film based on system of double zirconium and germanium oxides includes following components, wt %: crystallohydrate of zirconium oxochloride ZrOCl₂-8H₂O - 3.8-9.0; germanium tetrachloride - 3.0-7.1; 96% ethyl alcohol - remaining part.

EFFECT: thin films with formatin ofgermanium zirconate, stability of structure and physico-chemical properties in wide range of concentrations and high refraction index.

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Description

The invention relates to a technology for producing thin-film materials based on a double oxide system used in rapidly developing fields of electronic engineering and lighting industry, the construction industry, including integrated circuit technologies; as corrosion-resistant, decorative, filtering and redistributing radiation coatings.

A known composition for producing a film of zirconium dioxide (application for invention No. 93014629/33, 6 С04В 41/65, С04В 35/48, publ. 1995.06.09), used for coating glass. The composition for obtaining a film of zirconium dioxide includes crystalline zirconium oxychloride and contains 0.1 ... 1 wt.% Cobalt nitrate. The invention allows to reduce energy consumption and increase the productivity of the process of coating the base with a coating thickness of more than 100 nm.

The disadvantages of the known composition include the instability of the properties of the proposed films over time, due to structural transformations of polymorphic modifications of zirconium dioxide.

A known composition for the formation of thin-film materials based on zirconium and cobalt oxides as light distribution, protective and decorative coatings [V.V. Kozik, E. B. Chernov, L. P. Borilo, O. V. Turetskova, AM Shulpekov. The study of physical and chemical processes in film-forming ethanol solutions of zirconium salts, cobalt and the properties of thin films obtained on their basis. // Journal of Applied Chemistry. 2004. T 77. Issue 2, S.188-192]. Thin films of zirconium and cobalt double oxides are obtained by precipitation from a film-forming solution based on 99% ethyl alcohol, zirconium oxochloride ZrOCl ₂ · 8H ₂ O and cobalt salts CoCl ₂ · 6Н ₂ О or Co (NO ₃ ) ₂ · 6Н ₂ O с subsequent heat treatment. The total concentration of oxides in the obtained films is from 0 to 80 mol.% Cobalt oxide.

The disadvantages of the known composition include the lack of a stable range of properties within the concentration range from 0 to 80 mol% of cobalt oxide in the film due to the formation of mechanical mixtures in the system of double zirconium and cobalt oxides.

A known composition for producing a thin film based on zirconium and silicon oxides [R.V. Gryaznov, L.P. Borilo, V.V. Kozik, AMShulpekov. Thin films based on SiO ₂ and ZrO ₂ obtained from solutions. // Inorganic materials. 2001.V. 37. No. 7, S.828-831], selected as a prototype. Film-forming solutions are prepared from tetraethoxysilane, ethyl alcohol and zirconium oxochloride crystalline hydrate and applied to the substrates by centrifugation followed by heat treatment to the corresponding oxides in the concentration range from 0 to 100 wt.% Zirconia. The disadvantages of the known composition are low values of refractive indices, which degrades the properties of light-distributing coatings, as well as strictly specified concentrations of silicon and zirconium oxides, which provide the formation of a chemical compound in the system (67 wt.% Zirconium dioxide), complicate the reproducibility of the process.

The objective of the invention is to develop a composition for producing a thin film based on a system of double zirconium and germanium oxides, leading to the formation of a chemical compound (germanium zirconate), which ensures stability of the structure, physico-chemical and target properties in a wide range of concentrations, as well as achieving high values refractive index when used as redistributing radiation coatings.

The problem is solved in that the composition for producing a thin film based on the double oxide system includes the preparation of a film-forming solution containing ethyl alcohol, previously distilled and dried to 96 wt.% And zirconium oxochloride crystal hydrate, followed by centrifugation of this solution on a substrate and stepwise heat treatment , but unlike the prototype, germanium tetrachloride is additionally added to the composition in the following ratio of components, wt.%:

Zirconium oxochloride - 3.8-9.0;

Germany tetrachloride - 3.0-7.1;

Ethyl alcohol - the rest.

Among thin-film materials, films based on zirconium dioxide obtained by deposition from film-forming solutions (POR) are widely used, but the use of films of pure zirconium dioxide is limited. This is due to polymorphic transformations of the main crystalline modifications. To prevent bulk inversions, zirconia is stabilized by the introduction of germanium oxide structurally close to it, which leads to the formation in the film of a chemical compound of germanium zirconate (ZrGeO ₄ ) with scheelite structure. The presence of germanium zirconate makes it possible to maintain high and stable values of the refractive index in films based on the ZrO ₂ -GeO ₂ binary oxide system in the concentration range from 30 to 70 mol% GeO ₂ for a long time.

To obtain thin films based on the system of double zirconium and germanium oxides (ZrO ₂ -GeO ₂ ), a film-forming solution is prepared using 96 wt% ethyl alcohol preliminarily distilled and zirconium oxochloride is added in the form of ZrOCl ₂ · 8H ₂ O crystalline hydrate At room temperature, ZrOCl ₂ · 8H ₂ O is dissolved in ethanol with periodic stirring for 1-3 hours, depending on the concentration of zirconium oxochloride. Then, germanium tetrachloride (GeCl ₄ ) is added to the film-forming solution. After maturing the film-forming solution for 1-2 days, depending on the concentration of zirconium oxochloride, it is applied by centrifugation on an MPW-340 centrifuge at a speed of 3000-5000 rpm on glass, quartz and single-crystal silicon plates, then stepwise heat treatment is carried out before the formation of oxides in a thin film.

The most acceptable temperature for the storage of POR should be considered a temperature in the range of 22-25 ° C, for 6-10 months, depending on the concentration of zirconium oxochloride.

For the preparation of solutions, utensils of the second accuracy class are used.

The following are examples illustrating the invention.

Example 1

To prepare 100 ml of a film-forming solution, it is necessary to take 9.01 g of zirconium oxochloride crystalline hydrate and dissolve it in 70 ml of 96 wt.% Ethyl alcohol, then add 2.62 ml of germanium tetrachloride and bring to a volume of 100 ml with ethyl alcohol. After the solution has matured for 24 hours, POR is applied to the silicon substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 800 ° C for 1 hour, and a thin film of 30 mol% GeO ₂ is obtained and 70 mol.% ZrO ₂ 77 nm thick.

Example 2

To prepare 100 ml of a film-forming solution, it is necessary to take 7.72 g of zirconium oxochloride crystalline hydrate and dissolve it in 70 ml of 96 wt.% Ethyl alcohol, then add 3.49 ml of germanium tetrachloride and bring to a volume of 100 ml with ethyl alcohol. After the solution has matured for 24 hours, POR is applied to the silicon substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 800 ° C for 1 hour, and a thin film of 40 mol% GeO ₂ is obtained and 60 mol.% ZrO ₂ 78 nm thick.

Example 3

To prepare 100 ml of a film-forming solution, it is necessary to take 6.44 g of zirconium oxochloride crystalline hydrate and dissolve it in 70 ml of 96 wt.% Ethanol, then add 4.37 ml of germanium tetrachloride and bring to a volume of 100 ml ethanol. After the solution has matured for 24 hours, POR is applied to the silicon substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 800 ° C for 1 hour, and a thin film of 50 mol% GeO ₂ is obtained and 50 mol.% ZrO ₂ 78 nm thick.

Example 4

To prepare 100 ml of a film-forming solution, it is necessary to take 5.15 g of zirconium oxochloride crystalline hydrate and dissolve it in 70 ml of 96 wt.% Ethyl alcohol, then add 5.24 ml of germanium tetrachloride and bring to a volume of 100 ml with ethyl alcohol. After the solution has matured for 24 hours, POR is applied to the silicon substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 800 ° C for 1 hour, and a thin film of 60 mol% GeO ₂ is obtained and 40 mol.% ZrO ₂ 78 nm thick.

Example 5

To prepare 100 ml of a film-forming solution, it is necessary to take 3.86 g of zirconium oxochloride crystalline hydrate and dissolve it in 70 ml of 96 wt.% Ethanol, then add 6.11 ml of germanium tetrachloride and bring to a volume of 100 ml with ethyl alcohol. After the solution has matured for 24 hours, POR is applied to the silicon substrate by centrifugation and subjected to stepwise heat treatment at 60 ° C for 20 min and at 800 ° C for 1 hour, and a thin film of 70 mol% CeO ₂ is obtained and 30 mol.% ZrO ₂ 78 nm thick.

The table shows the physicochemical properties of the ZrO ₂ -GeO _{2 system} , depending on the composition of the starting components. It can be seen from the obtained data that films with a composition of 30 to 70 wt.% GeO ₂ have stable properties due to the formation of a chemical compound (zirconium germanate) in a thin film compared to compositions containing 20 and 80 wt.% GeO ₂ . High refractive indices in the obtained films allow their use in light-distributing, heat-reflecting coatings, as well as interference filters in projection equipment to prevent harmful thermal effects.

Physico-chemical properties of the films of the ZrO ₂ -GeO _{2 system} , depending on the composition of the starting components. Parameter Film composition The content of GeO ₂ in the film ZrO ₂ -GeO ₂ , mol.% twenty thirty 40 fifty 60 70 80 Film thickness, nm 65 77 78 78 78 78 95 Refractive index n 2.06 1.97 1.97 1.97 1.97 1.97 1.97 Adhesion F, MPa 1.85 1.65 1.65 1,64 1,63 1,63 1,08 Dielectric constant ε 10.12 7.22 7.21 7.21 7.20 7.20 5.65

Claims (1)

Composition for producing a thin film based on a double oxide system, comprising the following components, wt.%:
Zirconium oxochloride crystalline hydrate ZrOCl ₂ · 8H ₂ O 3.8-9.0 Germany tetrachloride 3.0-7.1 96% ethyl alcohol Rest