JP2011213847A - Silicon-containing sealing film, solar battery element and organic el element using the same, and manufacturing method for silicon-containing sealing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicon-containing sealing film having a high steam barrier property as compared with the conventional technology.SOLUTION: The silicon-containing sealing film includes a modified region formed by carrying out plasma irradiation on the principal surface of a polysilazane film. The modified region contains a silicon atom and a nitrogen atom, or a silicon atom, a nitrogen atom and an oxygen atom. The atomic composition is gradually varied in the modified region.

Description

  The present invention relates to a silicon-containing sealing film, a solar cell element using the silicon-containing sealing film, an organic EL element, and a method for producing a silicon-containing sealing film.

  Various semiconductor devices such as solar cells and organic EL elements are likely to be adversely affected by moisture and oxygen in the air. In order to operate these devices in a good state for a long time, it is widely performed to seal these elements with a sealing film. A silicon-containing compound film is preferably used as such a sealing film.

  In order to form a silicon-containing compound film, it has been proposed to form a polysilazane film on an object to be sealed and to heat it at a high temperature of 600 ° C. to 800 ° C. (see, for example, Patent Document 1). . In addition, the polysilazane film formed on the substrate is subjected to steam oxidation, and then heat-treated to form a silica film. It has also been proposed to use this silica film as a protective member (see, for example, Patent Document 2).

  However, in the former case, since a heat treatment at a very high temperature is required, there is a problem that applicable devices are limited. In the latter case, since a simple silica film is formed, its gas barrier property and water vapor barrier property are not always sufficient. For this reason, it has been difficult to provide a barrier film suitable for operating a device that easily deteriorates due to moisture, oxygen, or the like in a good state.

Japanese Patent Laying-Open No. 2005-033063 JP 2001-111076 A

"Thin Solid Films, 515, 3480-3487, Author: F. Rebib et al. (2007)

  In view of the above situation, an object of the present invention is to provide a silicon-containing sealing film exhibiting water vapor barrier properties.

The present invention is shown below.
[1] A modified region formed by performing plasma irradiation on the main surface of the polysilazane film,
The modified region includes a silicon atom and a nitrogen atom, or includes a silicon atom, a nitrogen atom, and an oxygen atom,
A silicon-containing sealing film in which an atomic composition is gradually changed in the modified region.
[2] The silicon-containing sealing film according to [1], wherein a maximum value of a composition ratio represented by the following formula (1) is 0.1 or more and 1 or less in the modified region.
Formula (1): Composition ratio of the nitrogen atom / (composition ratio of the oxygen atom plus composition ratio of the nitrogen atom)
[3] The silicon-containing sealing film according to [1] or [2], having a region where the composition ratio of the nitrogen atoms gradually increases from a surface of the modified region to a predetermined depth.
[4] The silicon-containing sealing film according to any one of [1] to [3], wherein at least one gas selected from an inert gas, a rare gas, and a reducing gas is used in the plasma irradiation.
[5] A solar cell element comprising the silicon-containing sealing film according to any one of [1] to [4].
[6] An organic EL device comprising the silicon-containing sealing film according to any one of [1] to [4].
[7] A step of performing plasma irradiation on the main surface of the polysilazane film to form a silicon-containing sealing film having a modified region,
The modified region includes a silicon atom and a nitrogen atom, or includes a silicon atom, a nitrogen atom, and an oxygen atom,
A method for producing a silicon-containing sealing film, wherein the atomic composition gradually changes in the modified region.
[8] The method for producing a silicon-containing sealing film according to [7], wherein in the plasma irradiation, at least one gas selected from an inert gas, a rare gas, and a reducing gas is used.

  ADVANTAGE OF THE INVENTION According to this invention, the silicon containing sealing film which shows water vapor | steam barrier property can be provided.

It is process sectional drawing which shows the manufacturing method of the silicon containing sealing film of this Embodiment. It is a chart which shows the result of having measured the composition in the depth direction by the X-ray photoelectron spectroscopy (XPS) method about the silicon containing sealing film obtained in Example 1. FIG. It is a chart which shows the result of having measured the composition of the polysilazane film | membrane obtained in the comparative example 1 in the depth direction by the X-ray photoelectron spectroscopy (XPS) method. It is a chart which shows the result of having measured the composition to the depth direction by the X ray photoelectron spectroscopy (XPS) method of the heat processing polysilazane film | membrane obtained in the comparative example 2. FIG. It is a chart which shows the result of having carried out the FT-IR measurement of the film | membrane obtained in Example 2 and Comparative Examples 3 and 4. FIG. It is a chart which shows the result of having measured the composition for the silicon containing sealing film obtained in Example 3 to the depth direction by the X-ray photoelectron spectroscopy (XPS) method. In addition, (a) is the result measured immediately after processing, and (b) is the result measured after 2 days. It is sectional drawing which shows typically the solar cell which concerns on this Embodiment.

FIG. 1 is a process cross-sectional view of the method for manufacturing a silicon-containing sealing film of the present embodiment.
(Silicon-containing sealing film 16)
The silicon-containing sealing film 16 is obtained by processing the polysilazane film 14. The silicon-containing sealing film 16 is obtained by performing energy ray irradiation 10 on the main surface of the polysilazane film 14 on the substrate 12. By this energy beam irradiation 10, a denatured region 18 is formed on the upper surface of the silicon-containing sealing film 16 (from the surface to a predetermined depth). On the other hand, in the silicon-containing sealing film 16, a slightly modified region 20 is formed below the modified region 18, that is, between the modified region 18 and the substrate 12. Further, the atomic composition may gradually change in the portion of the silicon-containing sealing film 16 in contact with the substrate 12 below the slightly modified region 20.

(Denatured region 18)
The modified region 18 includes silicon atoms and nitrogen atoms, or includes silicon atoms, nitrogen atoms, and oxygen atoms. The modified region 18 is composed of Si ₃ N ₄ , SiO _x N _y, or the like. That is, in the modified region 18, the nitrogen of the polysilazane film 14 remains as a constituent component such as Si ₃ N ₄ or SiO _x N _y without being released. In the modified region 18, the atomic composition gradually changes. Here, the atomic composition is a composition of silicon atoms and nitrogen atoms, or a composition of silicon atoms, nitrogen atoms and oxygen atoms.

(Slightly modified region 20)
On the other hand, the slightly modified region 20 has a region in which the change in atomic composition is smaller than that of the modified region 18. In the slightly denatured region 20, the variation of the atomic composition in the 10 nm film thickness is preferably within 5%.

Here, the atomic composition is measured under the following conditions.
The composition ratio of the constituent elements in the depth direction of the film is measured using an X-ray photoelectron spectroscopy (XPS) apparatus (“ESCALAB220iXL”, manufactured by VG). Note that AL-Kα is used as the X-ray source, and etching in the depth direction is performed by argon sputtering. The etching rate is a Si0 ₂ in terms of 0.05 nm / sec. In addition, the composition ratio of elements after 2 days from the energy beam irradiation treatment is measured.

The composition change of nitrogen atoms in the modified region 18 depends on the gas barrier performance of the substrate 12 sealed with the silicon-containing sealing film 16. Hereinafter, the composition change in the depth direction of nitrogen atoms measured by the depth direction analysis using X-ray photoelectron spectroscopy will be described.
The composition change in the depth direction of the nitrogen atoms in the modified region 18 may show a convex shape when the gas barrier performance of the substrate 12 is low, and monotonously when the gas barrier performance of the substrate 12 is sufficiently high. Shows an increasing trend. In the silicon-containing sealing film 16 immediately after the polysilazane film 14 is subjected to the energy beam treatment, the composition change in the depth direction of the nitrogen atoms in the modified region 18 tends to increase monotonously regardless of the gas barrier performance of the substrate 12. When the gas barrier performance of the substrate 12 is low, the oxidation reaction proceeds in a region on the lower surface side of the modified region 18 in the silicon-containing sealing film 16 with time, and the polysilazane has a very low nitrogen concentration. It changes to the composition mainly composed of silicon oxide. Therefore, when the gas barrier performance of the base material 12 is low, the composition change in the depth direction of the nitrogen atoms in the modified region 18 becomes a convex type.

In the modified region 18, the maximum value of the composition ratio (composition ratio of nitrogen atoms measured by X-ray photoelectron spectroscopy) represented by the following formula (1) is preferably 0.1 or more and 1 or less, more preferably It is 0.14 or more and 1 or less.
Composition ratio of nitrogen atom / (composition ratio of oxygen atom + composition ratio of nitrogen atom) (1)

By setting the maximum value of the composition ratio represented by the above formula (1) within the above range, the water vapor barrier property can be improved.
In order to modify the polysilazane film 14 and leave more nitrogen atoms in the modified region 18, for example, the plasma density can be increased or the processing time can be increased.

  In addition, the maximum value of the composition ratio of nitrogen atoms to all atoms in the modified region 18 is preferably 1 to 57 atom%, more preferably 10 to 57 atom%. The composition ratio of oxygen atoms to all atoms in the modified region 18 is preferably 0 to 65 atomic%, although it depends on the composition ratio of nitrogen atoms.

The silicon-containing sealing film 16 has a region where the composition ratio of nitrogen atoms gradually increases from the surface of the modified region 18 over a predetermined depth.
The initial composition ratio of nitrogen atoms on the surface of the modified region 18 can be, for example, 2 or more and 5 or less with respect to the maximum composition ratio of nitrogen atoms in the modified region 18. Thereby, water vapor | steam barrier property can be improved.

  The silicon-containing sealing film 16 having the modified region 18 having such a composition distribution is excellent in water vapor barrier properties. The silicon-containing sealing film 16 is particularly excellent in gas barrier properties such as oxygen barrier properties and mechanical properties such as scratch resistance. Further, by gradually changing the atomic composition on the lower surface side of the silicon-containing sealing film 16 (below the slightly denatured region 20), it is possible to improve the barrier property or improve the mechanical characteristics.

(Film thickness)
The film thickness (SiO ₂ equivalent film thickness) of the silicon-containing sealing film 16 is preferably 20 nm to 2 μm, more preferably 100 nm to 1 μm. The modified region 18 may be formed on a part of the upper surface of the silicon-containing sealing film 16. Further, the modified region 18 may be formed over the entire silicon-containing sealing film 16. In this case, the composition of the silicon-containing sealing film 16 is the same as that of the modified region 18.
Here, the film thickness (SiO ₂ equivalent film thickness) of the modified region 18 is, for example, (1/10) T to T, preferably (1), where T is the film thickness of the silicon-containing sealing film 16. / 5) T to (1/3) T. For example, when the thickness of the silicon-containing sealing film 16 is 150 nm to 500 nm, the thickness of the modified region 18 is a region having a depth of 50 nm from the upper surface of the modified region 18, preferably a depth from the upper surface to the lower direction. The region is 30 nm.

(Energy beam irradiation treatment)
Examples of the energy beam irradiation treatment include plasma treatment and ultraviolet treatment, but plasma treatment is preferred for the following reasons.

(A) In the ultraviolet treatment, there is a possibility that the ultraviolet rays transmitted through the polysilazane film 14 may damage the substrate 12. In the case of plasma treatment, the modified region 18 can be formed without damaging the base material 12 by selecting an appropriate gas type.
(B) The plasma treatment can form the denatured region 18 thinner than the ultraviolet treatment. Therefore, the modified region 18 having good barrier properties can be formed by plasma treatment even if the silicon-containing sealing film 16 is thin.
(C) In the plasma treatment, the thickness of the modified region 18 is thin, so that the amount of irradiation of energy rays forming the modified region 18 can be smaller than that in the ultraviolet treatment. Therefore, plasma processing is suitable for high-speed processing compared to ultraviolet processing. Further, in the plasma treatment, the formation rate of the modified region 18 can be increased by increasing the plasma density.
(D) In the plasma treatment, plasma that is a source of energy rays is formed in a space near the polysilazane film 14. Compared with the ultraviolet treatment in which the polysilazane film 14 is irradiated through the ultraviolet extraction window, the source of energy rays is very close to the polysilazane film 14. Therefore, the energy rays generated from the plasma are more isotropically irradiated onto the polysilazane film 14, and the polysilazane film 14 at the step portion also forms a modified region 18 having a high barrier property similar to the flat portion. Therefore, it is easier to obtain good barrier properties in the plasma treatment even if the substrate 12 has irregularities. Further, the plasma near atmospheric pressure has a thinner boundary region called a sheath formed on the polysilazane film 14 than the vacuum plasma, and therefore the source of energy rays is closer to the polysilazane film 14. Even if the substrate 12 has irregularities, plasma near atmospheric pressure is more preferable than vacuum plasma in the sense that good barrier properties are easily obtained.
(E) In the plasma treatment, by using a gas to which hydrogen, ammonia or the like is added as a treatment gas, it is possible to irradiate the polysilazane film 14 with reducing active species generated by plasma. Thereby, the oxidation reaction from the surface can be prevented, the modified region 18 having a higher nitrogen atom ratio can be formed, and good barrier properties can be easily obtained. In the ultraviolet treatment, it is difficult to efficiently generate reducing active species.
(F) Compared with the ultraviolet treatment, the plasma treatment provides a good water vapor barrier property with good reproducibility not only at a low pressure but also at an atmospheric pressure.
(G) In the plasma treatment, the distribution of the composition ratio of nitrogen atoms and oxygen atoms becomes sharp. On the other hand, in the ultraviolet treatment, the distribution of the composition ratio of nitrogen atoms and oxygen atoms becomes broad.

<Method for Producing Silicon-Containing Sealing Film 16>
The manufacturing method of the silicon-containing sealing film 16 of the present embodiment includes the following steps.
(A) a step of applying a polysilazane-containing liquid on the substrate 12 to form a coating film;
(B) a step of drying the coating film in a low oxygen / low moisture concentration atmosphere to form a polysilazane film 14;
(C) A step of performing energy ray irradiation 10 on the polysilazane film 14 to form a silicon-containing sealing film 16 including a modified region 18 formed on the upper surface.

[Step (a)]
In the step (a), a coating film containing polysilazane is formed on the substrate 12.
Although it does not specifically limit as a method of forming a coating film, It is preferable to form by a wet method, and the method of apply | coating a polysilazane containing liquid is specifically mentioned.

(Polysilazane)
As polysilazane, 1 type, or 2 or more types selected from perhydropolysilazane, organopolysilazane, and these derivatives can be used. Examples of the derivative include perhydropolysilazane or organopolysilazane in which part or all of hydrogen is substituted with an organic group such as an alkyl group or an oxygen atom.

In this embodiment, it is preferable to use perhydropolysilazane represented by H ₃ Si (NHSiH ₂ ) nNHSiH ₃ , but organopolysilazane in which part or all of hydrogen is substituted with an organic group such as an alkyl group may be used. Moreover, you may use by a single composition and may mix and use two or more components.

  A wet coating method can be used as a method for forming a polysilazane film. In this wet coating method, the step coverage of the object to be sealed is higher than dry coating methods such as vapor deposition. For this reason, it is thought that polysilazane is suitable as a raw material of a sealing material.

(catalyst)
The polysilazane-containing liquid may contain a metal carboxylate as a catalyst for converting polysilazane into a ceramic. The metal carboxylate is a compound represented by the following general formula.

(RCOO) _n M
[In the formula, R is preferably an aliphatic group or alicyclic group having 1 to 22 carbon atoms, M represents at least one metal selected from the following metal group, and n represents a metal M. It is a valence. ]

  M is selected from the group of nickel, titanium, platinum, rhodium, cobalt, iron, ruthenium, osmium, palladium, iridium, and aluminum, and is particularly preferably palladium (Pd). The metal carboxylate may be an anhydride or a hydrate. The metal carboxylate / polysilazane weight ratio is preferably 0.001-1, more preferably 0.01-0.5.

Moreover, an acetylacetonato complex is mentioned as another catalyst. The acetylacetonato complex containing a metal is a complex in which an anion acac- generated by acid dissociation from acetylacetone (2,4-pentadione) is coordinated to a metal atom, and is represented by the following general formula.
(CH ₃ COCHCOCH ₃ ) _n M
[Wherein, M represents an n-valent metal. ]

  M is selected from the group of nickel, titanium, platinum, rhodium, cobalt, iron, ruthenium, osmium, palladium, iridium, and aluminum, and is particularly preferably palladium (Pd). The weight ratio of acetylacetonato complex / polysilazane is preferably 0.001-1, more preferably 0.01-0.5.

Furthermore, as another catalyst, an acid compound such as an amine compound, pyridines, DBU, DBN, and / or an organic acid or an inorganic acid can be given.
Representative examples of amine compounds include those represented by the following general formula.
R ⁴ R ⁵ R ⁶ N

In the formula, R ^{4 to} R ⁶ each represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkylsilyl group, an alkylamino group, or an alkoxy group. Specific examples of the amine compound include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, butylamine, dibutylamine, tributylamine, pentylamine, dipentylamine, tripentylamine, Examples include hexylamine, dihexylamine, trihexylamine, heptylamine, diheptylamine, triheptylamine, octylamine, dioctylamine, trioctylamine, phenylamine, diphenylamine, and triphenylamine. The hydrocarbon chain contained in these amine compounds may be a straight chain or a branched chain. Particularly preferred amine compounds are triethylamine, tripentylamine, tributylamine, trihexylamine, triheptylamine and trioctylamine.

  Specific examples of pyridines include pyridine, α-picoline, β-picoline, γ-picoline, piperidine, lutidine, pyrimidine, pyridazine, and the like. Furthermore, DBU (1,8-diazabicyclo [5.4.0] -7-undecene), DBN (1,5-diazabicyclo [4.3.0] -5-nonene), and the like can also be used.

  Specific examples of the acid compound include organic acids such as acetic acid, propionic acid, butyric acid, valeric acid, maleic acid and stearic acid, and inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and hydrogen peroxide. Particularly preferred acid compounds are propionic acid, hydrochloric acid and hydrogen peroxide.

  The amount of the amine compound, pyridines, DBU, DBN, etc. and / or the acid compound such as organic acid or inorganic acid added to the polysilazane may be, for example, 0.1 ppm or more with respect to the weight of the polysilazane. Is 10 ppm to 10 wt%.

(Contains metal fine particles)
The polysilazane-containing liquid can contain metal fine particles. A preferred metal is Ag. The particle size of the metal fine particles is preferably smaller than 0.5 μm, more preferably 0.1 μm or less, and further preferably smaller than 0.05 μm. In particular, it is preferable to disperse independently dispersed ultrafine particles having a particle diameter of 0.005 to 0.01 μm in high boiling alcohol. The addition amount of the metal fine particles is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of polysilazane.

(solvent)
In the polysilazane-containing liquid, polysilazane and, if necessary, a catalyst and metal fine particles are dissolved or dispersed in a solvent.

  Examples of the solvent include aromatic compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, and triethylbenzene; n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, and i-heptane. , N-octane, i-octane, n-nonane, i-nonane, n-decane, i-decane and other saturated hydrocarbon compounds; ethylcyclohexane, methylcyclohexane, cyclohexane, cyclohexene, p-menthane, decahydronaphthalene, dipentene Ethers such as dipropyl ether, dibutyl ether, MTBE (methyl tertiary butyl ether) and tetrahydroxyfuran; ketones such as MIBK (methyl isobutyl ketone), methylene chloride, carbon tetrachloride and the like. May be mixed it may be used in.

(Application method)
As a coating method of the polysilazane-containing liquid, a known coating method can be applied and is not particularly limited. For example, a bar coating method, a roll coating method, a gravure coating method, a spray coating method, an air knife coating method, a spin coating method. Method, dip coating method and the like.

(Substrate 12)
As the base material 12 to which the silicon-containing sealing film 16 of the present invention is applied, in addition to a metal substrate such as silicon, a glass substrate, a ceramic substrate, a resin substrate, a resin film, etc., a substrate in which a thin film is laminated, or a thin film deposition A substrate on which elements are formed by performing fine processing is used. Moreover, as the base material 12, a photovoltaic cell or an organic EL substrate is preferably used.

  Before applying the polysilazane-containing liquid, the surface of the substrate 12 can be subjected to various surface treatments such as ultraviolet ozone treatment, corona treatment, arc treatment, or plasma treatment. These surface treatments may improve the adhesion between the polysilazane film 14 and the substrate 12.

[Step (b)]
In the step (b), the polysilazane-containing coating film formed in the step (a) is dried in a low oxygen / low moisture concentration atmosphere to form a polysilazane film 14.

  The drying treatment in step (b) is preferably performed in a low oxygen / low moisture concentration atmosphere. That is, the oxygen concentration is preferably in the range of 20% or less, more preferably 2000 ppm or less, and even more preferably 500 ppm or less. On the other hand, the moisture concentration is preferably 20% or less, more preferably 2000 ppm or less, and even more preferably 500 ppm or less. Note that the numerical range of the oxygen concentration and the numerical range of the moisture concentration can be combined as appropriate.

  By performing the drying process in such a low oxygen / low moisture concentration atmosphere, it is possible to more effectively suppress the polysilazane film 14 from being changed to silicon oxide (silica).

  The conditions for the drying treatment in the step (b) vary depending on the thickness of the polysilazane film 14, but in the present embodiment, for example, the temperature is about 120 ° C. for about 10 minutes. Moreover, you may perform the drying process of a process (b) in oven filled with inert gas, such as nitrogen and argon gas.

  When the drying process is performed in a low oxygen / low moisture concentration atmosphere, a necessary amount of oxygen atoms is introduced into the silicon-containing sealing film 16 by dissolved oxygen and water in the solvent. In order to prevent the silicon-containing sealing film 16 from containing oxygen atoms as much as possible, it is necessary to remove dissolved oxygen and moisture in the solvent.

[Step (c)]
In the step (c), the polysilazane film 14 is irradiated with energy rays 10 to form a silicon-containing sealing film 16. Examples of energy beam irradiation include plasma treatment and ultraviolet treatment, but plasma treatment is preferred.

(Plasma treatment)
The plasma treatment can be performed by a known method, and examples thereof include atmospheric pressure plasma or vacuum plasma.
Here, the “atmospheric pressure” of the atmospheric pressure plasma includes a pressure in the vicinity of the atmospheric pressure. In other words, it means that it can be used open to the atmosphere, it can be used in a closed container, and can be used in a slightly reduced pressure or slightly pressurized state compared to atmospheric pressure. . The pressure near atmospheric pressure refers to a pressure of 0.01 MPa to 0.11 MPa, for example. The atmospheric pressure plasma treatment can be easily incorporated as part of a series of manufacturing processes in an in-line process if it is used under atmospheric pressure without using a decompression device. On the other hand, if a closed container and a simple decompression device are used, for example, by using a slight decompression of about 0.01 MPa to 0.09 MPa, the amount of gas used for the treatment can be reduced, and an inhibitory component such as oxygen or water can be used. The amount can be reduced. Depending on the conditions, the denatured region 18 can be formed in a short time.
Moreover, in vacuum plasma, the processing operation can be performed under reduced pressure, that is, the processing operation can be performed at a pressure of, for example, less than 10,000 Pa. The operating pressure of the vacuum plasma treatment is preferably 1 Pa to 1000 Pa, more preferably 1 Pa to 500 Pa. By setting the amount within the above range, the amount of inhibitory components such as oxygen and water can be reduced. In addition, the denatured region 18 can be formed in a short time.

  As the gas species used for the plasma treatment, from the viewpoint of forming a modified region 18 having a high nitrogen concentration near the upper surface, nitrogen gas as an inert gas, argon gas as a rare gas, helium gas, neon gas, krypton gas, xenon Hydrogen gas, ammonia gas, and the like, which are gases that easily form reducing active species such as gas, are preferably used. More preferably, argon gas, helium gas, nitrogen gas, hydrogen gas, or a mixed gas thereof is used.

  Further, as the atmosphere used for the plasma treatment, it is preferable not only to use the above gas species but also to contain as little oxygen and water vapor as possible. For example, plasma treatment under normal pressure may be performed in an atmosphere having a low oxygen / low water concentration with an oxygen concentration of 50 ppm or less and a water concentration of 50 ppm or less.

  When the plasma treatment is performed in an atmosphere that satisfies the above conditions, the nitrogen concentration in the modified region 18 of this embodiment is high, and silicon oxide (silica) and silanol groups are unlikely to be generated, so that a sufficient water vapor barrier property can be obtained.

  As atmospheric pressure plasma, a gas is passed through between two electrodes to form a plasma and then irradiated onto the upper surface of the polysilazane film (remote method), or a substrate 12 with a polysilazane film 14 is disposed between the two electrodes, and gas is supplied there. There is a method of converting to plasma through a direct method. The direct method is preferable, in which the active species generated by plasma on the polysilazane film 14 can be irradiated without much deactivation. In order to lower the oxygen / water vapor gas concentration in the processing atmosphere, the atmospheric pressure plasma gas flow rate is preferably as high as possible, preferably 0.01 to 1000 L / min, more preferably 0.1 to 500 L / min. .

In the atmospheric pressure plasma treatment, the applied power (W), the unit area of the electrode (cm ²⁾ per preferably ^{0.0001W / cm 2 ~100W / cm 2} , more preferably 0.001W ^/ cm 2 ~50W ^/ cm ² . The moving speed of the base material 12 with the polysilazane film 14 in the atmospheric pressure plasma treatment is preferably 0.001 to 1000 m / min, and more preferably 0.001 to 500 m / min. The treatment temperature is room temperature to 200 ° C. The time of the atmospheric pressure plasma treatment is preferably 1 second to 60 minutes, more preferably 1 second to 20 minutes.

On the other hand, in vacuum plasma, a known electrode or waveguide is placed in a vacuum sealed system, and power such as direct current, alternating current, radio wave or microwave is applied through the electrode or waveguide. Arbitrary plasma can be generated. Power applied to the plasma treatment (W), the unit area of the electrode (cm ²⁾ per preferably ^{0.0001W / cm 2 ~100W / cm 2} , more preferably 0.001W ^/ cm ² ~50W ^/ cm 2 is there. The temperature of the vacuum plasma treatment is preferably room temperature to 500 ° C, and more preferably room temperature to 200 ° C in view of the influence on the substrate. The time for the vacuum plasma treatment is preferably 1 second to 60 minutes, more preferably 1 second to 20 minutes.

(UV treatment)
The ultraviolet treatment can be performed under atmospheric pressure or vacuum by a known method. Specifically, under a vacuum that does not contain oxygen and water vapor, in a low oxygen / low water concentration atmosphere (normal pressure) with an oxygen concentration of 50 ppm or less and a water concentration of 50 ppm or less, or in an inert gas, rare gas or reducing gas atmosphere ( Normal pressure).

  When the ultraviolet treatment is performed in an atmosphere that satisfies the above conditions, the nitrogen concentration in the modified region 18 of this embodiment is high, and silicon oxide (silica) and silanol groups are unlikely to be generated, so that a sufficient water vapor barrier property can be obtained.

  Examples of the method for generating ultraviolet rays include metal halide lamps, high-pressure mercury lamps, low-pressure mercury lamps, xenon arc lamps, carbon arc lamps, excimer lamps, and UV light lasers.

  By performing the above steps, the silicon-containing sealing film of this embodiment can be manufactured.

(Post-processing)
In the present embodiment, the following processing may be further performed on the silicon-containing sealing film 16.

  By subjecting the silicon-containing sealing film 16 whose upper surface has been modified by plasma treatment or ultraviolet treatment to irradiation or heating treatment of active energy rays, the modified region 18 in the silicon-containing sealing film 16 can be increased. it can.

  Examples of the active energy rays include microwaves, infrared rays, ultraviolet rays, and electron beams, and infrared rays, ultraviolet rays, and electron beams are preferable.

  Examples of the method for generating ultraviolet rays include metal halide lamps, high-pressure mercury lamps, low-pressure mercury lamps, xenon arc lamps, carbon arc lamps, excimer lamps, and UV light lasers.

  Examples of the method for generating infrared rays include a method using an infrared radiator or an infrared ceramic heater. Also, when using an infrared radiator, depending on the wavelength used for infrared rays, a near-infrared radiator having an intensity peak at a wavelength of 1.3 μm, a mid-infrared radiator having an intensity peak at a wavelength of 2.5 μm, and a wavelength of 4.5 μm A far-infrared radiator having an intensity peak can be used.

Further, it is preferable to use an infrared laser having a single spectrum. Specific examples of infrared lasers include gas chemical lasers such as HF, DF, HCl, DCl, HBr, and DBr, CO ₂ gas lasers, N ₂ O gas lasers, CO ₂ gas laser excited far infrared lasers (NH ₃ , CF ₄ , etc.), Pb (Cd) S, PbS (Se), Pb (Sn) Te, Pb (Sn) Se, and other compound semiconductor lasers (for example, an irradiation wavelength of 2.5 μm to 20 μm).

Next, the solar cell 100 according to the present invention will be described.
FIG. 7 is a cross-sectional view schematically showing the solar cell 100.
A solar cell 100 according to the present invention includes a substrate 104 (a solar cell substrate) and a solar cell element formed on at least a part of the substrate 104. This solar cell includes, for example, a transparent conductive layer 106, a photoelectric conversion layer 118, and a back electrode 116. The silicon-containing sealing film 102 of the present invention is formed so as to cover the solar cell element on the substrate 104, for example. In the solar cell 100 according to the present invention, the silicon-containing sealing film 102 of the present invention is formed on the back electrode 116. Such a solar cell 100 (thin film solar cell) performs photoelectric conversion using incident light 200 from the surface layer of the substrate 104.

  In the solar cell 100, the reflective layer 114 may be provided between the photoelectric conversion layer 118 and the back electrode 116. Further, if necessary, an impact absorbing layer (not shown) or a protective layer (back sheet) may be further formed on the silicon-containing sealing film 102 of the present invention (on the surface opposite to the substrate 104). As the shock absorbing layer, for example, Solar Eva (manufactured by Mitsui Chemicals Fabro) can be used. Various layers can be used as the protective layer from the viewpoints of barrier properties, mechanical properties, design properties, and the like.

  The substrate 104 (substrate for solar cell) is not particularly limited as long as it supports and reinforces the entire solar cell. For example, glass, polyimide, PET, PEN, PES, Teflon (registered trademark), etc. Heat resistant polymer films, metals such as stainless steel (SUS) and aluminum, ceramics, and the like can be used. These may be used alone or in a laminate.

  The film thickness of the substrate 104 can be, for example, about 0.1 mm to 30 mm. In addition, the substrate 104 may have irregularities formed on the surface. Further, the substrate 104 may be stacked with an insulating film, a conductive film, a buffer layer, and the like.

As the transparent conductive layer 106, a transparent conductive material such as ZnO, SnO ₂ , In ₂ O ₃ , or ITO can be used. These may be used alone or in a laminate.

  The film thickness of the transparent conductive layer 106 can be, for example, about 0.1 nm to 2.0 μm. The transparent conductive layer 106 can be formed by a sputtering method, a vacuum evaporation method, an EB evaporation method, an atmospheric pressure CVD method, a reduced pressure CVD method, a sol-gel method, an electrodeposition method, or the like.

  The photoelectric conversion layer 118 has a pin junction structure including a p-type microcrystalline silicon layer 108, an i-type microcrystalline silicon layer 110, and an n-type microcrystalline silicon layer 112. The photoelectric conversion layer 118 may have a plurality of pin junction structures. The p-type microcrystalline silicon layer 108, the i-type microcrystalline silicon layer 110, and the n-type microcrystalline silicon layer 112 may be formed of only microcrystalline silicon over the entire layer, or from the viewpoint of photoelectric conversion efficiency and the like, A layer containing crystalline silicon and a layer containing amorphous silicon may be mixed.

The p-type microcrystalline silicon layer 108 is a layer containing p-type impurities such as boron, aluminum, germanium, indium, and titanium. The p-type impurity concentration can be, for example, about 0.01 atomic% to 8 atomic%. The film thickness of the p-type microcrystalline silicon layer 108 can be, for example, about 1 nm to 200 nm. The p-type microcrystalline silicon layer 108 may be a single layer or may be formed of a composite layer including a plurality of layers having different or gradually changing p-type impurity concentrations.
The p-type microcrystalline silicon layer 108 can be formed by atmospheric pressure CVD, low pressure CVD, plasma CVD, ECR plasma CVD, high temperature CVD, low temperature CVD, microwave CVD, catalytic CVD, sputtering, or the like.

The i-type microcrystalline silicon layer 110 is an intrinsic semiconductor that does not exhibit p-type and n-type conductivity, but exhibits a very weak p-type or n-type conductivity as long as the photoelectric conversion function is not impaired. May be. The film thickness of the i-type microcrystalline silicon layer 110 can be, for example, about 0.1 μm to 10 μm.
The i-type microcrystalline silicon layer 110 can be formed in the same manner as the p-type microcrystalline silicon layer 108 except that a gas containing p-type impurities is not used.

The n-type microcrystalline silicon layer 112 is a layer containing n-type impurities such as phosphorus, arsenic, and antimony. The n-type impurity concentration can be, for example, about 10 ¹⁸ cm ⁻³ to 10 ²⁰ cm ⁻³ . The film thickness of the n-type microcrystalline silicon layer 112 can be, for example, about 10 nm to 100 nm. The n-type microcrystalline silicon layer 112 can be formed in the same manner as the p-type microcrystalline silicon layer 108 except that, for example, a gas containing an n-type impurity is used as the dopant gas.

The reflective layer 114 can be a transparent conductive film made of SnO ₂ , In ₂ O ₃ , ZnO, ITO, or the like. The film thickness of the reflective layer 114 can be, for example, about 50 nm. The reflective layer 114 can be formed by, for example, a magnetron sputtering method.

  As the back electrode 116, materials such as Ag, Al, Cu, Au, Ni, Cr, W, Ti, Pt, Fe, and Mo can be used. These may be used alone or in a laminate. The film thickness of the back electrode 116 can be, for example, about 100 nm to 1 μm. The back electrode 116 can be formed by, for example, a sputtering method or a vacuum deposition method.

  For example, the silicon-containing sealing film 102 of the present invention is formed on the back electrode 116 so as to cover the entire solar cell element. The silicon-containing sealing film 102 of the present invention is formed according to the above manufacturing method.

  As described above, after the laminated structure is formed, it is divided into individual elements. And the electrode 120 is each pulled out from the transparent conductive layer 106 and the back surface electrode 116, and the solar cell 100 can be obtained.

  The solar cell 100 according to the present invention can convert the incident light 200 into electric energy by using the light confinement effect in the photoelectric conversion layer 118. And in the solar cell 100 which concerns on this invention, it seals with the silicon-containing sealing film 102 so that the board | substrate 104 may be covered. For this reason, an adverse effect can be reduced by moisture in the air or the like. Therefore, the solar cell 100 according to the present invention can operate for a long time in a good state.

  As described above, the silicon-containing sealing film of the present invention is preferably used for sealing various semiconductor devices such as solar cell elements and organic EL elements. The silicon-containing sealing film of the present invention can be directly formed on the surface of various semiconductor devices. In addition, the silicon-containing sealing film of the present invention can be formed by a process that does not require a high temperature, and has a higher water vapor gas barrier property than the prior art. For this reason, it can utilize suitably as a sealing film of a solar cell substrate or an organic EL substrate. Therefore, the industrial applicability of the present invention is high.

  The present invention is not limited to the above-described embodiments and specific examples, and can be appropriately changed without departing from the object of the present invention.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

The evaluation methods of Examples and Comparative Examples are as follows.
(Composition analysis in the depth direction of the film)
The composition ratio of the constituent elements in the depth direction of the film was measured using an X-ray photoelectron spectroscopy (XPS) apparatus (“ESCALAB220iXL”, manufactured by VG). Note that AL-Kα was used as the X-ray source, and etching in the depth direction was performed by argon sputtering. The etching rate is a Si0 ₂ in terms of 0.05 nm / sec.
In addition, from the measurement results of the above composition ratio, it was determined whether (a) the atomic composition continuously changed greatly in the vicinity of the upper surface (SiO ₂ equivalent film thickness: 0 (upper surface) to 30 nm depth).
(B) The maximum value of the composition ratio of nitrogen atoms was determined according to the definition of the following formula.
Formula: composition ratio of nitrogen atom / (composition ratio of oxygen atom + composition ratio of nitrogen atom)

(Membrane structure analysis)
Using an infrared visible spectroscopy (FT-IR) apparatus (“FT / IR-300E”, manufactured by JASCO Corporation), an FT-IR spectrum was measured to evaluate the bonding state of atoms in the film.
In the above FT-IR spectrum, the peak top attributed to O-Si-O or O-Si-N in Non-Patent Document 1 is higher than the peak peak attributed to O-Si-0 or O-Si-N. With reference to a graph showing the relationship between the wave number and the O / (O + N) ratio (FIG. 6 in the literature), the ratio [N / (O + N)] of nitrogen atoms to oxygen atoms is set to [N / (O + N)] = 1. -Calculated from [O / (O + N)].

(Water vapor transmission rate measurement)
It measured using the water vapor transmission rate measuring apparatus ("PERMATRAN3 / 31", the MOCON company make) using the isobaric method one infrared sensor method in 40 degreeC90% RH atmosphere. The lower limit of detection of this device is 0.01 g / m ² / day.

<Example 1>
A silicon substrate (thickness: 530 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) is spin-coated (10 s, 3000 rpm) with a 20 wt% xylene (dehydrated) solution of polysilazane (NL110A, manufactured by AZ Electronic Materials Co., Ltd.), and 120 in a nitrogen atmosphere. A polysilazane film having a thickness of 160 nm was prepared by drying at a temperature of 10 ° C. for 10 minutes. Drying was performed in an atmosphere having an oxygen concentration of about 500 ppm and a water vapor concentration of about 500 ppm.
This polysilazane film was subjected to vacuum plasma treatment under the following conditions.
Then, the film composition was measured by depth direction analysis using X-ray photoelectron spectroscopy.
Vacuum plasma processing equipment: Utec Co., Ltd. Gas: Ar
Gas flow rate: 50 mL / min
Pressure: 19Pa
Temperature: Room temperature Applied power per side of electrode unit surface: 1.3 W / cm ²
Frequency: 13.56MHz
Processing time: 5 min

<Comparative Example 1>
A silicon substrate (thickness: 530 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) is spin-coated (10 s, 3000 rpm) with a 20 wt% xylene (dehydrated) solution of polysilazane (NL110A, manufactured by AZ Electronic Materials Co., Ltd.), and 120 in a nitrogen atmosphere. A polysilazane film having a thickness of 160 nm was prepared by drying at a temperature of 10 ° C. for 10 minutes. Drying was performed in an atmosphere having an oxygen concentration of about 500 ppm and a water vapor concentration of about 500 ppm.
Then, the film composition was measured by depth direction analysis using X-ray photoelectron spectroscopy.

<Comparative example 2>
A polysilazane film was formed on a silicon substrate by the same operation as in Comparative Example 1. Subsequently, the polysilazane film was subjected to heat treatment at 250 ° C. for 1.5 hours in an air atmosphere.
Then, the film composition was measured by depth direction analysis using X-ray photoelectron spectroscopy.

(Contrast of Examples and Comparative Examples)
Changes in the film composition in the depth direction of Example 1 and Comparative Examples 1 and 2 measured by X-ray photoelectron spectroscopy are shown in FIGS. 2 to 4 show the summary of the film composition in the vicinity of the upper surface.
In Example 1 in which plasma treatment was performed, the atomic composition continuously changed greatly, whereas in Comparative Example 1 of the untreated polysilazane film and Comparative Example 2 in which heat treatment was performed, the change in the film composition in the vicinity of the upper surface was observed. It is hardly seen. The O / Si ratio of the heat-treated comparative example 2 is about 2, and it is estimated that the entire film is mainly changed to silica.
Further, the maximum value of the composition ratio of nitrogen atoms in the vicinity of the upper surface of Example 1 is as large as 0.43.

<Example 2>
A silicon substrate (thickness: 530 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) is spin-coated (10 s, 3000 rpm) with a 2 wt% xylene (dehydrated) solution of polysilazane (NL110A, manufactured by AZ Electronic Materials Co., Ltd.), and 120 under a nitrogen atmosphere. A polysilazane film having a thickness of 25 nm was produced by drying at a temperature of 10 ° C. for 10 minutes. Drying was performed in an atmosphere having an oxygen concentration of about 500 ppm and a water vapor concentration of about 500 ppm.
This polysilazane film was subjected to vacuum plasma treatment under the same conditions as in Example 1.
Then, the bonding state of atoms inside the prepared film was evaluated by FT-IR analysis.

<Comparative Example 3>
A silicon substrate (thickness: 530 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) is spin-coated (10 s, 3000 rpm) with a 2 wt% xylene (dehydrated) solution of polysilazane (NL110A, manufactured by AZ Electronic Materials Co., Ltd.), and 120 under a nitrogen atmosphere. A polysilazane film having a thickness of 25 nm was produced by drying at a temperature of 10 ° C. for 10 minutes. Drying was performed in an atmosphere having an oxygen concentration of about 500 ppm and a water vapor concentration of about 500 ppm.
Then, the bonding state of atoms inside the prepared film was evaluated by FT-IR analysis.

<Comparative example 4>
A polysilazane film was formed on a silicon substrate by the same operation as in Comparative Example 1. Subsequently, the polysilazane film was subjected to heat treatment at 250 ° C. for 1.5 hours in an air atmosphere.
Then, the bonding state of atoms inside the prepared film was evaluated by FT-IR analysis.

(Contrast of Examples and Comparative Examples)
FIG. 5 shows the FT-IR spectra of the thin films of Example 2 and Comparative Examples 3 and 4, each having a thickness of 25 nm. The results of analyzing the spectrum of FIG. 5 are summarized in Table 2.
In Example 2, ^Si-N derived from silicon oxynitride (SiON) (850cm -1), whereas the peak of ^{O-Si-N (980cm -1} ) were observed, treatment as Comparative Example 3 In the non-polysilazane film, only the peak of Si—N (830 cm ⁻¹ ) derived from the raw material polysilazane can be seen. Furthermore, in the heat-treated film as in Comparative Example 4, the peak of O—Si—O (1050 cm ⁻¹ ) derived from silica is large, and unlike in Example 1, the heat treatment mainly forms a silica layer. You can see that
Therefore, it is estimated that the modified layer formed in the vicinity of the upper surface of Example 1 is also made of silicon oxynitride (SiON), as in Example 2.

<Example 3>
A polyimide film (thickness 20 μm, “Kapton 80EN”, manufactured by Toray DuPont Co., Ltd.) was bar-coated with a 5 wt% xylene (dehydrated) solution of polysilazane (NL110A, manufactured by AZ Electronic Materials Co., Ltd.). A polysilazane film having a thickness of 0.5 μm was produced by drying under the above conditions.
Subsequently, vacuum plasma treatment was performed under the same conditions as in Example 1.
And the film | membrane composition was measured by the depth direction analysis using the X ray photoelectron spectroscopy about the film | membrane immediately after a process and 2 days after. Moreover, the water vapor transmission rate was measured for the membrane immediately after the treatment and after 2 days.

<Comparative Example 5>
As Comparative Example 5, the water vapor transmission rate of the base material polyimide film (thickness 20 μm, “Kapton 80EN”, manufactured by Toray DuPont Co., Ltd.) used in Example 3 was measured.

<Comparative Example 6>
In the same manner as in Example 3, a 0.5 μm polysilazane film was formed on a polyimide film (thickness 20 μm, “Kapton 80EN”, manufactured by Toray DuPont Co., Ltd.).
And the film | membrane composition was measured by the depth direction analysis using the X ray photoelectron spectroscopy about the film | membrane immediately after a process. Moreover, the water vapor transmission rate was measured about the film | membrane immediately after a process.

<Comparative Example 7>
In the same manner as in Example 6, a 0.5 μm polysilazane film was formed on a polyimide film (thickness 20 μm, “Kapton 80EN”, manufactured by Toray DuPont Co., Ltd.).
Subsequently, the polysilazane film was subjected to heat treatment at 250 ° C. for 1.5 hours in an air atmosphere.
And about the film | membrane after a process, the film | membrane composition was measured by the depth direction analysis using the X ray photoelectron spectroscopy. Moreover, the water vapor transmission rate was measured about the film | membrane after a process.

(Contrast of Examples and Comparative Examples)
In order to evaluate the barrier performance of the silicon-based sealing film, a water vapor transmission rate was measured using a polymer film (polyimide film) having a low Gallia performance as a base material. The film composition was measured by depth direction analysis using X-ray photoelectron spectroscopy. Since it was found that the film composition in the depth direction after the plasma treatment changes with the elapsed time after the treatment, the measurement of the film composition and the water vapor transmission rate in the depth direction is performed immediately after the plasma treatment and two days after the plasma treatment. This was done on the film. The change in the film composition in the depth direction of Example 3 is shown in FIG. Table 3 shows a summary of the film composition in the vicinity of the upper surface from the XPS measurement results of Example 3 and Comparative Examples 6 and 7. Table 3 also shows the measurement results of the water vapor transmission rate of Example 3 and Comparative Examples 5 to 7.
As can be seen from Comparative Examples 5 and 6, the water vapor permeability of the polysilazane film formed on the polyimide film and that of the polyimide film itself are equivalent, and the water vapor barrier property of the polysilazane film is almost absent.
As can be seen from the results of Example 3, the composition in the depth direction of the film is almost unchanged at 30 nm from the upper surface immediately after the treatment and after 2 days, but greatly changes in a region having a depth of 30 nm or more. . However, the water vapor transmission rate is below the detection limit (<0.01 g / m ² / day) both immediately after the treatment and after 2 days. For this reason, it is considered that a very good water vapor barrier property is borne by the modified region in the vicinity of the surface formed by the plasma treatment.
In addition, the change in the film composition in the depth direction seen in Example 3 is a phenomenon caused by using a polymer film (polyimide film) having a low barrier performance as a base material in comparison with Example 1. . When the gas barrier performance of the substrate is low, the oxidation reaction proceeds in the region on the lower surface side from the modified region near the upper surface due to gas permeation from the substrate side as time passes. For this reason, it is considered that in the region on the lower surface side from the modified region, the polysilazane that has not been modified by the plasma treatment changes to a composition mainly composed of silicon oxide having a very low nitrogen concentration. It can be seen that the film composition in the depth direction immediately after the treatment is partially oxidized in the region on the lower surface side in contact with the modified region, and the oxidation reaction starts to proceed. Therefore, when the gas barrier performance of the base material is low, the composition change in the depth direction of the nitrogen atoms in the modified region near the upper surface becomes convex. The maximum value of the composition ratio of nitrogen atoms in the vicinity of the upper surface shows a large value of 0.5 or more.
On the other hand, since the silicon substrate used in Example 1 is excellent in gas barrier properties, it is considered that the region on the lower surface side from the modified region near the upper surface is not oxidized and remains polysilazane.
Further, as can be seen from the result of the heat-treated comparative example 7, the water vapor transmission rate when the entire film is mainly changed to silica is 0.7 g / m ² / day, which is one digit or more larger than that of the example 3. . On the other hand, from Comparative Example 6, the water vapor barrier property of the polysilazane film is almost absent. Therefore, also from comparison with Comparative Examples 6 and 7, it is considered that the very good water vapor barrier property of Example 3 is borne by the modified region in the vicinity of the surface formed by the plasma treatment.
Therefore, the modified layer in the vicinity of the upper surface having a very good water vapor barrier property needs to have a large composition change continuously in the vicinity of the upper surface, and the N / (N + O) ratio in the vicinity of the upper surface needs to have a large value.

（＊１） Ｏ−ＳｉＯまたはＯ−Ｓｉ−Ｎ由来のピークトップ波数

(* 1) Peak top wavenumber derived from O-SiO or O-Si-N

DESCRIPTION OF SYMBOLS 10 Energy beam irradiation 12 Base material 14 Polysilazane film 16 Silicon-containing sealing film 18 Denatured region 20 Slightly modified region 100 Solar cell 102 Silicon-containing sealing film 104 Substrate 106 Transparent conductive layer 108 p-type microcrystalline silicon layer 110 i-type microcrystal Silicon layer 112 n-type microcrystalline silicon layer 114 Reflective layer 116 Back electrode 118 Photoelectric conversion layer 120 Electrode 200 Incident light

Claims (8)

A modified region formed by performing plasma irradiation on the main surface of the polysilazane film,
The modified region includes a silicon atom and a nitrogen atom, or includes a silicon atom, a nitrogen atom, and an oxygen atom,
A silicon-containing sealing film in which an atomic composition is gradually changed in the modified region. 2. The silicon-containing sealing film according to claim 1, wherein a maximum value of a composition ratio represented by the following formula (1) is 0.1 or more and 1 or less in the modified region.
Formula (1): Composition ratio of the nitrogen atom / (composition ratio of the oxygen atom plus composition ratio of the nitrogen atom)   3. The silicon-containing sealing film according to claim 1, wherein the silicon-containing sealing film has a region where the composition ratio of the nitrogen atoms gradually increases from a surface of the modified region to a predetermined depth.   The silicon-containing sealing film according to claim 1, wherein at least one gas selected from an inert gas, a rare gas, and a reducing gas is used in the plasma irradiation.   The solar cell element provided with the silicon containing sealing film of any one of Claim 1 to 4.   An organic EL device comprising the silicon-containing sealing film according to claim 1. Performing a plasma irradiation on the main surface of the polysilazane film, and forming a silicon-containing sealing film having a modified region,
The modified region includes a silicon atom and a nitrogen atom, or includes a silicon atom, a nitrogen atom, and an oxygen atom,
A method for producing a silicon-containing sealing film, wherein the atomic composition gradually changes in the modified region.   The method for producing a silicon-containing sealing film according to claim 7, wherein in the plasma irradiation, at least one gas selected from an inert gas, a rare gas, and a reducing gas is used.

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