JP2013185175A - Transparent oxide film, method for manufacturing the same, and oxide sputtering target - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zinc oxide-based transparent oxide film having a low refractive index and a good gas barrier property, a method for producing the same, and an oxide sputtering target.
A transparent oxide film has a total amount of one or two of Ga and In of 0.5 to 12 at%, Si of 15 to 54 at%, and Mg of 5 to 5 with respect to the total amount of metal components. It is an oxide having a component composition containing 36 at% and the balance being Zn and inevitable impurities. Moreover, the sputtering target for producing this transparent oxide film has a total of one or two of Ga and In of 0.3 to 5 at% and Si of 11 to 30 at with respect to the total amount of metal components. %, Mg is contained in an amount of 5 to 20 at%, and the balance is composed of an oxide sintered body having a component composition composed of Zn and inevitable impurities.
[Selection] Figure 1

Description

  The present invention relates to a gas barrier layer used for electronic paper such as a liquid crystal display element, an electroluminescence display element, an electrophoretic display element, and a toner display element, a film type solar cell, and the like, and a transparent electrode layer of a thin film solar cell using a compound semiconductor The present invention relates to a zinc oxide-based transparent oxide film having excellent gas barrier properties, a method for producing the same, and an oxide sputtering target.

  Conventionally, a gas barrier layer used for electronic paper such as a liquid crystal display element, an electroluminescence display element, an electrophoretic display element, a toner display element, a film type solar cell, and the like, and a thin film solar cell using a compound semiconductor (for example, CIGS (Cu-- As a gas barrier layer on a transparent electrode layer of an (In-Ga-Se) solar cell), a technique for producing a transparent oxide film by a sputtering method is known.

  For example, Patent Document 1 contains tin oxide and at least one additive element selected from the group consisting of Si, Ge, and Al. The additive element is based on the total content of the additive element and Sn. It is contained at a ratio of 15 atomic% to 63 atomic%, and the composition of the crystal phase includes at least one of a metal phase of the additive element, an oxide phase of the additive element, and a composite oxide phase of the additive element and Sn. An oxide sintered body in which an oxide phase of the additive element and a composite oxide phase of the additive element and Sn are dispersed with an average particle size of 50 μm or less is used as a sputtering target, and direct current A method of forming a transparent oxide film on the surface of a resin film substrate by a sputtering method using a pulsing method has been proposed.

  The transparent oxide film obtained by this method is a transparent oxide film containing tin oxide and at least one additional element selected from the group consisting of Si, Ge, and Al. It is contained at a ratio of 15 atomic% to 63 atomic% with respect to the total of the additive element and Sn, is an amorphous film, and has a refractive index of 1.90 or less at a wavelength of 633 nm.

Patent Document 2 discloses that at least one mixed thin film layer mainly composed of a mixture of ZnS and SiO ₂ is formed on one or both surfaces of a polymer film substrate, and a resin is formed on the mixed thin film layer. A gas barrier film in which at least one layer is laminated is described. This mixed thin film layer is formed by sputtering with a high frequency applied using a sputtering target which is a mixed sintered material formed of ZnS and SiO ₂ .

JP 2007-290916 A JP 2010-208072 A

The following problems remain in the conventional technology.
That is, in the target described in Patent Document 1, a large amount of nodules is generated at the time of sputtering, and it takes time to clean the apparatus. Therefore, a transparent oxide film having excellent gas barrier properties other than tin oxide is desired. Has been.
In addition, the gas barrier film described in Patent Document 2 is manufactured by sputtering with a high frequency applied. However, in order to form a film at a higher speed, the gas barrier film needs to be a film that can be formed by DC sputtering.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a zinc oxide-based transparent oxide film having a low refractive index and good gas barrier properties, a method for producing the same, and an oxide sputtering target. To do.

The inventors of the present invention applied SiO ₂ or MgO to a GZO (Ga-Zn-O: Gallium doped Zinc Oxide), IZO (In-Zn-O: Indium doped Zinc Oxide) film. Since it has been found that when it is contained, the film becomes amorphous and the gas barrier property is improved, as a transparent oxide film, a ZnO—SiO ₂ —MgO—Ga ₂ O ₃ system or ZnO—SiO ₂ —MgO—In _{2 is used.} Research was conducted to form an O ₃ -based film by sputtering. In this research, it was found that a transparent film having a low refractive index and a high gas barrier performance can be obtained by setting the atmosphere during sputtering film formation or the temperature of the substrate to a specific condition.

Therefore, the present invention has been obtained from the above findings, and the following configuration has been adopted in order to solve the above problems. That is, in the transparent oxide film according to the first invention, the total of one or two of Ga and In is 0.5 to 12 at%, Si is 15 to 54 at% with respect to the total metal component amount, Mg is contained in an amount of 5 to 36 at%, and the balance is an oxide having a component composition consisting of Zn and inevitable impurities. The refractive index average value in the visible light region with a wavelength of 400 to 750 nm is 1.9 or less, The transmittance average value in the visible light region is 90% or more and is amorphous.
That is, in this transparent oxide film, the total of one or two of Ga and In is 0.5 to 12 at%, Si is 15 to 54 at%, and Mg is 5 to 36 at% with respect to the total metal component amount. %, And the balance is an oxide having a component composition consisting of Zn and inevitable impurities, has a low refractive index and a high transmittance in the visible light region, and is amorphous, and thus has a high gas barrier property (for example, water vapor It has a barrier property.

The transparent oxide film according to the second invention is characterized in that, in the first invention, the water vapor transmission rate is 0.03 g / (m ² · day) or less.
That is, in this transparent oxide film, since the water vapor transmission rate is 0.03 g / (m ² · day) or less, the water vapor barrier property is high. Therefore, the transparent oxide film is laminated on the resin film substrate used for electronic paper and solar cells It is suitable for a gas barrier layer.

The transparent oxide film according to the third invention is characterized in that in the first or second invention, the transparent oxide film has a component composition in which a part of Ga and In is replaced with Al.
That is, in this transparent oxide film, a lower cost film can be obtained by substituting a part of Ga and In for an inexpensive material Al.

The transparent oxide film according to the fourth invention is characterized in that, in the third invention, the ratio of Al / (Ga + In + Al) is 0.05 to 0.95 in atomic ratio.
That is, in this transparent oxide film, since the ratio of Al / (Ga + In + Al) is 0.05 to 0.95 in atomic ratio, abnormal discharge and particles during sputtering are caused by the co-doping effect of Ga and In and Al. Generation can be reduced.

An oxide sputtering target according to a fifth invention is a sputtering target for producing the transparent oxide film according to any one of the first and second inventions, and includes Ga and In with respect to the total amount of metal components. Oxide sintering having a component composition of 0.3 to 5 at% of the total of one or two of them, 11 to 30 at% of Si, 5 to 20 at% of Mg, and the balance consisting of Zn and inevitable impurities It consists of a body.
That is, in this oxide sputtering target, the total of one or two of Ga and In is 0.3 to 5 at%, Si is 11 to 30 at%, and Mg is 5 to 20 at based on the total amount of metal components. %, And the balance is composed of an oxide sintered body having a component composition consisting of Zn and inevitable impurities, so that the transparent oxide film of the present invention can be stably formed by DC sputtering with high conductivity. .

An oxide sputtering target according to a sixth invention is a sputtering target for producing the transparent oxide film of the third or fourth invention, and includes Ga, In and Al with respect to the total metal component amount. Sintered oxide having a composition of 0.3 to 5 at% in total including two or more Al, 11 to 30 at% Si, 5 to 20 at% Mg, and the balance consisting of Zn and inevitable impurities It consists of a body.
That is, since this oxide sputtering target contains 0.3 to 5 at% in total of two or more kinds including Al in Ga, In and Al, Ga and In are inexpensive materials and are used as targets. By substituting Al for conductivity, a lower cost target can be obtained.

A method for producing a transparent oxide film according to a seventh invention is a method for producing a transparent oxide film according to any one of the first to fourth inventions, and the oxide sputtering target according to the fifth or sixth invention. The sputtering is performed by applying a direct current in an atmosphere of an inert gas containing oxygen and at least one of an environment in which the substrate is heated.
That is, in this method for producing a transparent oxide film, sputtering is performed in an inert gas atmosphere containing oxygen and at least one environment in which the substrate is heated. Improves and the refractive index decreases. In addition, since the film is formed at a high speed by DC sputtering, it is denser and has better barrier properties than the film formed by RF sputtering.

Here, the reason for limiting the content ratio of the metal component elements in the transparent oxide film and the oxide sputtering target of the present invention as described above is as follows.
Ga, In:
Ga and In are added to the sputtering target as a dopant to ZnO to enable DC sputtering, and are contained in the film as a result of sputtering film formation. If Ga and In are less than the above content range, the conductivity of the target is insufficient and DC sputtering cannot be performed. Moreover, when there are more Ga and In than the said content range, the crystallinity of a film | membrane will become high and gas barrier property will fall.

Si:
Si, together with Mg, has the effect of improving the gas barrier properties by reducing the crystallinity of the film and reducing the path of water vapor and gas. When Si is less than the above content range, the crystallinity of the film is increased, the gas barrier property is lowered, and the refractive index is increased. Further, if Si is more than the above content range, a complex oxide is formed with Zn, the crystallinity is increased, the gas barrier property is lowered, and it is necessary for sputtering a film having a desired composition. Therefore, the amount of Si in the target is increased, the conductivity is lowered, and DC sputtering cannot be performed.

Mg:
Mg, together with Si, has the effect of improving the gas barrier properties by reducing the crystallinity of the film and reducing the path of water vapor and gas. When Mg is less than the above content range, the crystallinity of the film is increased, and the gas barrier property is lowered. On the other hand, if Mg is more than the above content range, a complex oxide is formed with Al and Zn, the crystallinity is increased, the gas barrier property is lowered, and a film having a desired composition is formed by sputtering. As a result, the amount of Mg required for the target increases, the conductivity becomes low, and DC sputtering cannot be performed.

In the fourth invention, the range of the composition ratio of Ga, In and Al is set because the ratio of Al / (Ga + In + Al) is in the range of 0.05 to 0.95 in terms of atomic ratio, This is because if it is not contained, the abnormal discharge and particle suppression effect during sputtering by co-doping with Ga, In and Al cannot be obtained.
Al:
Al is added to the sputtering target as a dopant to ZnO in order to reduce cost and enable stable DC sputtering, and is contained in the film as a result of sputtering film formation. If the ratio of Al / (Ga + In + Al) is in the range of 0.05 to 0.95 in terms of atomic ratio and Al is not contained, abnormal discharge and particle suppression during sputtering by co-doping with Ga, In and Al The effect is not obtained.

The present invention has the following effects.
That is, according to the transparent oxide film of the present invention, one or two of Ga and In, Si and Mg are contained within the above range with respect to the total amount of metal components, with the balance being Zn and inevitable. An oxide having a component composition composed of impurities, having a low refractive index and a high transmittance in the visible light region, and being amorphous, it has a high gas barrier property.
Further, according to the oxide sputtering target according to the present invention, one or two of Ga and In, Si and Mg are contained within the above range with respect to the total amount of metal components, and the balance is Zn and inevitable. Since it consists of oxide sinter which has the component composition which consists of an impurity, it has high electroconductivity and can form stably the transparent oxide film of the said invention by DC sputtering.
Furthermore, according to the method for producing a transparent oxide film according to the present invention, DC sputtering can be performed using the oxide sputtering target, and at least in an inert gas atmosphere containing oxygen and a state in which the substrate is heated. Since sputtering is performed by applying a direct current under one environment, a transparent oxide film having the above composition with high transparency can be formed.
Therefore, by adopting the transparent oxide film of the present invention for gas barrier layers such as electronic paper and solar cells, the required high transparency, low refractive index and high gas barrier properties can be obtained, and it has high reliability and is visible. High-performance electronic paper, solar cells with good conversion efficiency, and the like can be manufactured.

It is a flowchart which shows the manufacturing process of the sputtering target to be used in one Embodiment of the transparent oxide film which concerns on this invention, its manufacturing method, and a sputtering target.

  Hereinafter, an embodiment of a transparent oxide film, a manufacturing method thereof, and a sputtering target according to the present invention will be described with reference to FIG.

The transparent oxide film of the present embodiment is a film used as a gas barrier layer for the above-described applications, and is one of Ga and In with respect to the total metal component amount or the total metal component amount or It is an oxide having a component composition containing 0.5 to 12 at% of the total of two types, 15 to 54 at% of Si, 5 to 36 at% of Mg, and the balance of Zn and inevitable impurities. Moreover, this transparent oxide film may contain 0.5-12 at% of the total of 2 or more types including Al in Ga, In, and Al. Furthermore, it is preferable that the content of Ga, In, Al is 0.05 to 0.95 in terms of the atomic ratio of Al / (Ga + In + Al).
Further, this transparent oxide film has a refractive index average value in a visible light region of a wavelength of 400 to 750 nm of 1.9 or less, a transmittance average value in the visible light region of 90% or more, It is crystalline. The transparent oxide film preferably has a water vapor transmission rate of 0.03 g / (m ² · day) or less.
The water vapor transmission rate is measured by the Mocon method in accordance with JIS standard K7129 method.

Moreover, the oxide sputtering target for producing the transparent oxide film of the present embodiment has a total of one or two of Ga and In of 0.3 to 5 at%, based on the total metal component amount. It consists of an oxide sintered body containing 11 to 30 at% of Si, 5 to 20 at% of Mg, and the balance being composed of Zn and inevitable impurities.
In addition, this oxide sputtering target may contain 0.3-5 at% of the sum total of 2 or more types containing Al in Ga, In, and Al. Furthermore, it is preferable that the content of Ga, In, Al is 0.05 to 0.95 in terms of the atomic ratio of Al / (Ga + In + Al).
Furthermore, the method for producing a transparent oxide film of the present embodiment uses the above-described oxide sputtering target to generate a direct current in an inert gas atmosphere containing oxygen and in at least one environment where the substrate is heated. Input and sputtering (DC sputtering).

  At this time, the resin film base material is used as the substrate, and the heating temperature of the substrate is set in the range of 100 to 200 ° C. Further, the partial pressure of oxygen with respect to the whole atmosphere gas of oxygen and inert gas is set to 0.05 or more and 0.2 or less.

The method of producing the oxide sputtering target includes a step of weighing at least one of Ga ₂ O ₃ powder and In ₂ O ₃ powder, MgO powder, SiO ₂ powder, and ZnO powder and mixing them to obtain a mixed powder; And a step of sintering the mixed powder. This sintering can be realized by using a normal pressure sintering method, HP, or HIP method.
Further, instead of at least one of Ga ₂ O ₃ powder and In ₂ O ₃ powder, Al ₂ O ₃ powder may be weighed so as to have the above-mentioned atomic ratio and mixed with each of the above powders to obtain a mixed powder. .

An example of the above production method will be described in detail. For example, as shown in FIG. 1, first, at least one of Ga ₂ O ₃ powder and In ₂ O ₃ powder having a purity of 99.9% or more (when Al is added, Al ₂ O ₃ powder is also included) and a MgO powder and SiO ₂ powder and ZnO powder were weighed so that the content range, the powder obtained was placed and a zirconia ball in a plastic container (polyethylene pot) Wet-mix for a predetermined time with a ball mill device to obtain a mixed powder. For example, alcohol is used as the solvent.

Next, after drying the obtained mixed powder, it is hot-pressed in a vacuum at a pressure of 200 kgf / cm ² at, for example, 1200 ° C. for 5 hours to obtain a sintered body. The hot press temperature is preferably in the range of 1100 to 1250 ° C., the time is preferably in the range of 1 to 10 hours, and the pressure is preferably in the range of 100 to 400 kgf / cm ² .
The hot-pressed sintered body is usually machined to a target shape using electrical discharge machining, cutting or grinding, and the processed target is In or soldered to Cu or SUS (stainless steel) or others. Bonding to a backing plate made of metal (for example, Mo) and subjecting to sputtering.

In order to DC-sputter the transparent oxide film of this embodiment using this sputtering target, the sputtering target is set in a magnetron sputtering apparatus, the input power density is 0.8 to 12 W / cm ² , and the ultimate vacuum is set. 5 × 10 ⁻⁴ Pa or less, sputtering pressure is 0.3 to 20 Pa, sputtering gas partial pressure is in the range of O ₂ / (Ar + O ₂ ) of 0.05 to 0.2, and substrate heating temperature is 100 to 200 ° C. Under certain conditions, a film is formed on a resin film substrate.

Thus, in the transparent oxide film of this embodiment, the total of one or two of Ga and In is 0.5 to 12 at%, Si is 15 to 54 at%, and Mg is based on the total metal component amount. Is an oxide having a component composition consisting of Zn and inevitable impurities, and has a low refractive index and a high transmittance in the visible light region, and is amorphous, so it has a high gas barrier property. Have.
In particular, the refractive index average value in the visible light region is 1.9 or less, the transmittance average value is 90% or more, the water vapor transmittance is 0.03 g / (m ² · day) or less at a thickness of 100 nm. Therefore, since it has a low refractive index, a high transmittance, and a high water vapor barrier property, it is suitable for a gas barrier layer or the like laminated on a resin film substrate used for electronic paper or solar cells.
Furthermore, in this transparent oxide film, Ga and In can be replaced with Al which is an inexpensive material by containing 0.5 to 12 at% of the total of two or more kinds including Ga, In and Al. Therefore, a lower cost film can be obtained. More preferably, the content of Ga, In, and Al is 0.05 to 0.95 in terms of the ratio of the atomic number ratio of Al / (Ga + In + Al), thereby exhibiting abnormal discharge and particle reduction effects during sputtering. Can do.

  Moreover, in the oxide sputtering target for producing this transparent oxide film, the total of one or two of Ga and In is 0.3 to 5 at% and Si is 11 with respect to the total amount of metal components. The transparent oxide film of the present invention having high conductivity by DC sputtering because it is made of an oxide sintered body having a component composition containing Zn and unavoidable impurities, and containing 30 to 30 at%, Mg 5 to 20 at% Can be formed stably.

  Further, by containing 0.3 to 5 at% of the total of two or more of Ga, In and Al containing Al, Ga and In can be replaced with Al which is an inexpensive material and brings conductivity to the target. Thus, the target can be made at a lower cost. Further, by simultaneously doping at least one of Ga and In and Al into ZnO, abnormal discharge and particle generation during sputtering can be suppressed.

  In the method for producing the transparent oxide film, a direct current is applied in the inert gas atmosphere containing oxygen and at least one environment where the substrate is heated using the oxide sputtering target. Since sputtering is performed, the transparency of the formed transparent oxide film is improved.

In addition, since the heating temperature of the substrate is set in the range of 100 to 200 ° C., it is sufficiently transparent as a gas barrier layer employed in electronic paper and solar cells while suppressing the thermal effect on the resin film substrate to be formed. And a transparent oxide film having a low refractive index.
Furthermore, since the partial pressure of oxygen with respect to the whole atmospheric gas of oxygen and inert gas is set to 0.05 or more, sufficient transparency and a low refractive index as a gas barrier layer employed in electronic paper and solar cells A transparent oxide film having

  The result evaluated about the Example of the transparent oxide film and oxide sputtering target which were produced based on the said this embodiment is demonstrated below.

Manufacture of the Example of this invention was performed on condition of the following.
First, at least one of Ga ₂ O ₃ powder (4N, D ₅₀ = 1.7 μm) and In ₂ O ₃ powder (4N, D ₅₀ = 1 μm) (when Al is added so as to have the composition ratio shown in Table 1. Includes Al ₂ O ₃ powder (4N, D ₅₀ = 0.2 μm), MgO powder (3N, D ₅₀ = 0.4 μm), SiO ₂ powder (3N, D ₅₀ = 5 μm) and ZnO powder (4N , D ₅₀ = 1 μm), and the obtained powder and 4 times the amount (weight ratio) of zirconia balls (balls with a diameter of 5 mm) are put in a 10 L plastic container (polyethylene pot) and placed in a ball mill apparatus. For 48 hours to obtain a mixed powder. In addition, alcohol was used for the solvent.
Here, for example, D ₅₀ = 1 μm indicates that the particle size of 50% of the particles in the powder is 1 μm or less.

Next, the obtained mixed powder was dried and then vacuum hot pressed at 1200 ° C. for 5 hours at a pressure of 200 kgf / cm ^{2 to} obtain a sintered body.
The sintered body thus hot pressed is machined into a target shape (diameter 125 mm, thickness 10 mm), and the processed one is bonded to a backing plate made of oxygen-free copper. A sputtering target was produced.

Furthermore, these sputtering targets were set in a magnetron sputtering apparatus, and the power source: DC, input power: 500 W, ultimate vacuum: 1 × 10 ⁻⁴ Pa, sputtering gas partial pressure (of oxygen and inert gas (Ar) Refractive index under the condition that the partial pressure of oxygen with respect to the whole atmospheric gas: O ₂ / (Ar + O ₂ )) is 0.05 or more and 0.2 or less, the sputtering pressure is 0.67 Pa, and the substrate heating is 100 ° C. to 200 ° C. In addition, a film thickness of 100 nm is formed on a glass substrate (Corning # 1737 length: 20 mm × width: 20 mm, thickness: 0.7 mm) for transmittance measurement, and a PET film (length: 100 mm for water vapor transmittance measurement). X side: 100 mm, thickness: 120 μm) A transparent film having a thickness of 100 nm was tried.

  In addition, as a sputtering target and a transparent oxide film of a comparative example, on the conditions shown in Table 1, what set the target composition and the film composition out of the scope of the present invention (Comparative Examples 1 to 8) was the same as the above example. Produced. That is, as the transparent oxide film of the comparative example, the composition of the sputtering target was adjusted, and the composition of Ga in the transparent oxide film was outside the range of 0.5 to 12 at% (Comparative Examples 1 and 2), The composition of Si in the transparent oxide film was outside the range of 15 to 54 at% (Comparative Examples 3 and 4), and the composition of Mg in the transparent oxide film was out of the range of 5 to 36 at% ( Comparative Examples 5 and 6), those in which the composition of Ga and Al in the transparent oxide film was outside the range of 0.5 to 12 at% (Comparative Example 7), and the film formation conditions were set outside the range of the present invention. (Comparative Example 8) was prepared in the same manner as in the above example.

When the film compositions of the transparent oxide films of Examples and Comparative Examples of the present invention thus prepared were measured by ICP emission analysis, each metal component relative to all metal components was as shown in Table 2. When the film was analyzed by EPMA, it was confirmed that oxygen was uniformly distributed throughout the entire structure and each metal element was present as an oxide in the film.
Table 2 shows the results of X-ray diffraction (XRD) analysis of the transparent oxide films of Examples and Comparative Examples of the present invention and the presence or absence of crystal peaks.

The refractive index of each transparent oxide film obtained was measured with a spectroscopic ellipsometer (UVISEL NIR manufactured by HORIBA Jobin Yvon), and the transmittance was measured with a spectrophotometer (V-550 manufactured by JASCO Corporation). The measured results are shown in Table 2.
Furthermore, the water vapor transmission rate (water vapor barrier property) was measured based on JIS standard K7129 method using the Mocon method and using PERMATRAN-WMODEL 3/33 manufactured by mocon. The measured results are shown in Table 2.

As a result of these evaluations, in Comparative Example 1, the electric resistance value of the target was too high and DC sputtering could not be performed.
In Comparative Example 2, a complex oxide (ZnGa ₂ O ₄ , ZnIn ₂ O ₄ ) structure was formed on the target, abnormal discharge occurred frequently, and DC sputtering could not be performed. Therefore, when RF sputtering was performed, a complex oxide phase was formed on the film. Precipitation occurred and the water vapor barrier property was poor.

In Comparative Example 3, the amount of Si added is small and the refractive index is high. Moreover, since the coarse crystal precipitated and the amorphous structure collapsed, the water vapor barrier property was poor.
In Comparative Example 4, a complex oxide (ZnGa ₂ O ₄ , ZnIn ₂ O ₄ ) structure was formed on the target, abnormal discharge occurred frequently, and DC sputtering could not be performed. Therefore, when RF sputtering was performed, the complex oxide (Zn ₂ SiO ₄ ) Was deposited, and the water vapor barrier property was poor.
In Comparative Example 5, since the amount of Mg added is small, the crystallinity of the film is high, coarse particles are precipitated, and the water vapor barrier property is lowered.
In Comparative Example 6, since the electric resistance value of the target was too high and DC sputtering could not be performed, when RF sputtering was performed, a composite oxide phase was deposited on the film, and the water vapor barrier property was poor.
In Comparative Example 7, since the electric resistance value of the target was too high and DC sputtering could not be performed, when RF sputtering was performed, the composite oxide phase was deposited on the film, so that the water vapor barrier property was poor.
In Comparative Example 8, the sputtering film forming conditions of the present invention are not satisfied. Even when the sputtering target of the present invention is used, oxygen vacancies remain in the film unless substrate heating and oxygen addition are performed, so that the refractive index in the visible light region is high and the visible light transmittance is low.

On the other hand, in all Examples of the present invention, no crystal peak was observed by XRD, and the water vapor transmission rate was 0.03 g / (m ² · day) or less, and the water vapor barrier property was high. ing. In any of the examples, the refractive index in the visible light region having a wavelength of 400 to 750 nm is 1.9 or less and the transmittance in the visible light region is as high as 90% or more, and has a low refractive index and a high transmittance. The film which has is obtained.
Examples 28, 29, 31, and 32 contain Ga, In, and Al so that the atomic ratio of Al / (Ga + In + Al) is in the range of 0.05 to 0.95. As shown in FIG. 3, the number of abnormal discharges during continuous sputtering was reduced and particles were also reduced.

In order to use the oxide sputtering target of the present invention, relative density: 90% or more, surface roughness: Ra value 2 μm or less, Rz value 15 μm or less, particle size: 3 μm or less, electric resistance: 1.0 × It is preferable that 10 ¹ Ω · cm or less, metal impurity concentration: 0.1 atomic% or less, and bending strength: 120 MPa or more. Each of the above-described embodiments satisfies these conditions.
The technical scope of the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention.

Claims (7)

  The total amount of one or two of Ga and In is 0.5 to 12 at%, Si is 15 to 54 at%, Mg is 5 to 36 at%, and the balance is Zn and inevitable with respect to the total amount of metal components. An oxide film having a component composition composed of impurities, having an average refractive index in the visible light region of a wavelength of 400 to 750 nm of 1.9 or less, and an average transmittance of 90% in the visible light region. A transparent oxide film characterized by being amorphous as described above. The transparent oxide film according to claim 1,
A transparent oxide film having a water vapor transmission rate of 0.03 g / (m ² · day) or less. The transparent oxide film according to claim 1 or 2,
A transparent oxide film having a component composition in which a part of Ga and In is replaced with Al. The transparent oxide film according to claim 3,
A transparent oxide film having an atomic weight ratio of Al / (Ga + In + Al) of 0.05 to 0.95. A sputtering target for producing the transparent oxide film according to claim 1 or 2,
The total amount of one or two of Ga and In is 0.3 to 5 at%, Si is 11 to 30 at%, Mg is 5 to 20 at% with respect to the total metal component amount, and the balance is Zn and inevitable An oxide sputtering target comprising an oxide sintered body having a component composition comprising impurities. A sputtering target for producing the transparent oxide film according to claim 3 or 4,
The total amount of two or more types including Al in Ga, In and Al is 0.3 to 5 at%, Si is 11 to 30 at%, Mg is 5 to 20 at% with respect to the total metal component amount, and the balance is An oxide sputtering target comprising an oxide sintered body having a component composition comprising Zn and inevitable impurities. A method for producing the transparent oxide film according to any one of claims 1 to 4,
Sputtering using an oxide sputtering target according to claim 5 or 6 by applying a direct current in at least one of an inert gas atmosphere containing oxygen and a state in which the substrate is heated. A method for producing a transparent oxide film.

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