SU1758085A1 - Method of vacuum deposition of thin dielectric films - Google Patents

Abstract

Usage: the invention can be used in the plenary technology for the production of semiconductor devices for obtaining passivating coatings in integrated circuits, dielectric films of thin-film electroluminescent structures, etc. SUBSTANCE: invention allows as a result of introducing oxygen into an argon-nitrogen gas mixture of high-frequency magnetron discharge when sputtering a silicon target with maintaining the gas ratio, respectively, AgN, 02 equal to 40: 53: 7, to obtain high-quality silicon oxynitride coatings by ensuring optimal combination of dielectric and mechanical properties of the resulting film. Improving the quality of the films is provided by increasing the breakdown voltage (up to 5.5.10 V / cm), reducing the dielectric loss (-l 008) with a dielectric constant of not less than 6-7, and also the method according to the invention improves the stability of these properties, reduces the mechanical stresses, increases adhesion. 4 il. cl

Description

The invention relates to the field of film microelectronics and can be used in a planar technology for producing semiconductor devices for producing passivating coatings in integrated circuits, dielectric films of thin-film electroluminescent structures, films for multi-component compositions, used as structural elements of integrated optics.

As a prototype, a method was chosen dedicated to obtaining a dielectric film of oxides, nitrides, carbides, sputtering targets made of aluminum and silicon. In various reactive media, in particular, the preparation of a film of silicon nitride (Si3N4) in a mixture of argon-nitrogen, nitride films is mentioned. The silicon obtained in this way has good dielectric and optical properties, but due to high mechanical stresses, poor adhesion to various materials, and also due to the effect of degradation of dielectric properties in the process kspluatatsii these films have not found use in display devices based on thin-film electroluminescence.

The purpose of the invention is the expansion of technological capabilities by producing a high-quality electroluminescent coating of silicon oxynitride

X SL 00 O 00 SL

The invention provides an increase in the quality of films by increasing the breakdown voltage (up to 5.5.106 V / cm), reducing dielectric losses (igd -0.008) with a dielectric constant of at least 6-7, increasing the stability of these properties, reducing mechanical stresses, increasing adhesion.

The goal is achieved by replacing the argon-nitrogen mixture with the argon-nitrogen-oxygen mixture and by selecting the gas ratios that provide the optimal combination of the dielectric optical and mechanical properties of the resulting film. The introduction of oxygen into the dielectric film and the optimization of the ratio of the partial pressures of the gas components makes it possible to increase the adhesion, sharply reduce the internal stresses in the film and obtain the optimal combination of the dielectric and optical properties of the resulting film.

Fig. 1 shows the dependence of the absorption coefficient of a dielectric film on the nitrogen content of an argon-nitrogen mixture. The dependence has a clear minimum corresponding to 60% nitrogen (40% Ar). A sharp increase in the absorption coefficient with a decrease in the nitrogen content (with an increase in the argon content) is apparently associated with the appearance of nonstoichiometric silicon in the film. With a nitrogen content of more than 60%, the absorption coefficient also increases, although not so dramatically, which is apparently associated with an excess of nitrogen in the film. Thus, the optimal ratio of argon-reactive gas is 40%: 60%.

Fig. 2 shows the dependence of the absorption coefficient on the content of 40% Ar- (60-x)% Na-x% Oa oxygen in the mixture. When the oxygen content is less than 6%, the absorption coefficient begins to increase sharply, with an increase in oxygen of more than 7%, the increase is insignificant, but the refractive index drops sharply (Fig. 3) and the dielectric film degenerates into silica with e 3.8-4.0.

Figure 4 shows the dielectric properties of the silicon oxynitride film as a function of the oxygen content in the mixture. When the oxygen content in the mixture is 7%, we have a maximum in electrical strength (5.5.106 V / cm) and a minimum in losses (dd 0.01), with e 6.5-6.8.

Thus, the optimization of dielectric and optical properties gives the following ratio of components in the gas mixture: 40% Ar, 53% №, 7% 02

Let us give an example of the implementation of the proposed method for the preparation of oxynitride

films. The film is sprayed with a silicon target 200 mm in diameter and 8 mm thick onto a rotating glass substrate 170x140 mm in size coated with

a transparent conductive film based on a mixture of indium and tin oxides. It uses an RF magnetron device with a 200 mm magnetic system, made on the basis of samarium – cobalt magnets. The frequency of the RF field is 13.56 MHz, the magnitude of the magnetic field above the target surface is 0.08 T, the automatic displacement on the target is 700-800 V. The distance of the target substrate is 200 mm, the temperature of the substrate during the deposition process is maintained at 200 ° C. silicon target is produced in an argon-nitrogen-oxygen mixture with a ratio of partial pressures

Ag / № / 02 40/53/7 and the total pressure of 3.10 mm Hg The deposition rate of the deposited films is 400-500 A / min, the thickness of the deposited films is 0.1-0.3 microns. The installation contained an optical control device that allows to obtain films of a given thickness.

The use of the method allows to obtain oxynitride films on substrates of a relatively large area, which have the following advantages over films obtained by existing methods (direct nitriding, chemical and plasma chemical deposition, RF magnetron sputtering

ceramic target): optimal electrophysical characteristics (maximum electrical strength, dielectric loss close to minimal, dielectric constant is quite high) with high optical transparency; high uniformity of characteristics on the area of the substrate; high performance and good reproducibility of parameters; low mechanical stresses and good adhesion to a wide class of dielectric and semiconductor materials.

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Claims (1)

Invention Formula The method of vacuum deposition of a thin dielectric film, including the sputtering of a silicon target in a high-frequency magnetron discharge plasma 5 with ions of a gas mixture containing argon and nitrogen, and the deposition of a sputtered material on a substrate, in order to expand technological capabilities by obtaining a high-quality dielectric coating of silicon oxynitride, the gas mixture is added at the ratio of gases At N2 (b. ian, oxygen is introduced in addition, and the precipitation is n. 40:53 7, respectively % 7-6 54 J 21-i i i t-i-g 1-g 15 50 55 60 65 70 75 80 85 90 ft 1 % ten 9 8 7 6 5- ii- 1y 10123 4 5 6 7 to 9 10 ft. Oxygen content,% FIG. 2 t-i-g 1-g  ft 4g + ng % l l t, 9 16V-6- t, 51 2 J 4 56 7 8 9 S 1112 Table of Contents xucsopoffa, & Figz Ohno fyW in / cm four 4f7 6-5-4 JT 2 one Ohno