TWI761664B - Oxide sputtering target, manufacturing method thereof, and oxide thin film formed using the oxide sputtering target - Google Patents

Abstract

An oxide sputtering target containing MoO ₂ and In ₂ O ₃ , the Mo content satisfies 0.1≦Mo/(In+Mo)≦0.8 in atomic ratio, and the relative density is 80% or more. A method for manufacturing an oxide sputtering target is characterized in that: indium oxide powder and molybdenum oxide powder are hot-pressed and sintered in a reducing gas environment or an inactive environment. An object of the present invention is to provide a high-density oxide sputtering target and a method for producing the same.

Description

Oxide sputtering target, manufacturing method thereof, and oxide thin film formed using the oxide sputtering target

The present invention relates to an oxide sputtering target suitable for forming transparent electrodes in light-emitting elements such as organic electroluminescent elements, a method for producing the same, and an oxide thin film formed using the oxide sputtering target.

As a transparent electrode (anode) in light-emitting elements such as organic electroluminescent elements, ITO (indium-tin oxide) is used. The positive holes injected by applying a voltage to the anode are combined with electrons in the light-emitting layer through the positive hole transport layer. In recent years, in order to improve the efficiency of charge injection into the positive hole transport layer, the use of oxides having a higher work function than ITO has been studied. For example, in Patent Document 1, it is disclosed to use an oxide (In—Mo—O) containing indium (In) and molybdenum (Mo).

The In-Mo-O film as a transparent electrode is usually formed by a vacuum evaporation method. For example, Patent Document 1 discloses film formation by arc discharge ion plating. Moreover, in Patent Documents 2 and 3, it is described that a film is formed using an electron beam vapor deposition method, a high-density plasma-assisted vapor deposition method, or the like. At this time, film formation was performed using a plate composed of an oxide sintered body produced by sintering indium oxide powder and molybdenum oxide powder as a vapor deposition source (cited documents 1 to 3). prior art literature Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2002-231054 Patent Document 2: Japanese Patent No. 2017-206746 Patent Document 3: Japanese Patent No. 2017-214227

[The problem to be solved by the invention]

As described above, the In-Mo-O film has been formed by the vacuum deposition method. The vacuum vapor deposition method is a method of heating the vapor deposition source in a vacuum to vaporize and sublime it, and deposit the vapor deposition source that becomes a gas on a substrate to form a film. The strength is weak, and the composition changes during evaporation. Furthermore, depending on the arrangement of the substrates, there are cases where the film thickness distribution is not suitable for forming a film on a large-area substrate. As a means for eliminating such a disadvantage, a sputtering method can be mentioned.

However, in the sputtering method, since Ar ions have high energy during sputtering and collide with the sintered body, there is a problem that the sintered body is broken if the strength of the sintered body is weak. In order to prevent splashing (bumping, bumping), the density of the sintered body plate for vacuum evaporation is deliberately reduced, and the low-density plate with low strength cannot be directly used as a sputtering target. In view of such a problem, it is an object of the present invention to provide a sputtering target composed of an oxide of In-Mo-O having a high relative density, a method for producing the same, and an oxide thin film formed using the oxide sputtering target. . [Technical means to solve the problem]

One aspect of the present invention is 1) an oxide sputtering target, which contains MoO ₂ and In ₂ O ₃ , the content of Mo satisfies 0.1≦Mo/(In+Mo)≦0.8 in terms of atomic ratio, and the relative density is more than 80%. 2) The oxide sputtering target according to 1) above, wherein the XRD peak intensity of the (-111) plane belonging to the MoO ₂ phase is set to I _{MoO 2} and the (-111) plane belonging to the MoO ₃ phase is When the XRD peak intensity of the 021) plane is set to I _MoO3 , the XRD peak intensity ratio I _MoO2 /I _MoO3 is 3 or more. Further, 3) The oxide sputtering target according to 1) or 2) above, which has a volume resistivity of 10 mΩ·cm or less.

One aspect of the present invention is 4) a method for producing an oxide sputtering target, which is the method for producing an oxide sputtering target according to any one of the above 1) to 3), characterized in that indium oxide is The powder and the molybdenum oxide powder are mixed, and the mixed powder is hot-pressed and sintered at a temperature of 950° C. or higher and 1100° C. or lower. Further, 5) The method for producing an oxide sputtering target according to 4) above, wherein MoO ₂ powder is used as the molybdenum oxide powder. [Effect of invention]

According to the present invention, a high-density In-Mo-O oxide sputtering target can be produced, whereby the oxide thin film can be formed by a sputtering method. In addition, the oxide thin film formed using this oxide sputtering target exhibits excellent weather resistance.

The oxide sputtering target of the embodiment of the present invention contains MoO ₂ and In ₂ O ₃ , and the content of Mo satisfies 0.1≦Mo/(In+Mo)≦0.8 in terms of atomic ratio. Its components are substantially composed of indium (In), molybdenum (Mo) and oxygen (O), but it may also contain inevitable impurities contained in the raw materials within the range that does not significantly change the characteristics of the target. Inevitable impurities, sintering aids, etc. mixed with the crushing medium.

Mo content (atomic ratio) Mo/(In+Mo) is 0.1 or more and 0.8 or less. By setting the Mo content to 0.1 or more, excessive reduction of In ₂ O ₃ can be suppressed in the sintering step, and by setting the Mo content to 0.8 or less, it becomes easy to produce a high-density sintered body. The Mo content (atomic ratio) Mo/(In+Mo) is preferably 0.3 or more and 0.5 or less. By setting it as 0.3 or more, a desired sputtered film with a high work function can be obtained, and by setting it as 0.5 or less, the weather resistance of the sputtered film can be improved.

In the embodiment of the present invention, the relative density of the oxide sputtering target is 80% or more. Molybdenum oxides include MoO ₂ and MoO ₃ , but since MoO ₂ has a higher true density than MoO ₃ , even with the same In/Mo ratio, the dimensional density at the same volume is higher than that of MoO ₂ . In the embodiment of the present invention, the high density of the sputtering target is intended to be achieved by making molybdenum oxide mainly exist in the form of MoO ₂ .

The relative density (%) is calculated from size density/theoretical density×100, and the theoretical density varies depending on the ratio of In to Mo. Therefore, higher or lower densities are preferred for comparison of the same composition and higher, rather than comparison of different compositions and higher. Therefore, in the present invention, the theoretical density is obtained in consideration of the ratio of In and Mo, and the evaluation is performed based on the relative density obtained from the theoretical density. Thus, the densities of targets of different compositions can be compared.

In addition, the theoretical density also differs depending on the phases of the oxides (MoO ₂ , MoO ₃ ), there are cases where the raw material phases are different, or the phases change during the firing process, and the relative densities are different even if they are compared with the same composition Condition. Therefore, in the embodiment of the present invention, the theoretical density is calculated using the theoretical density based on MoO ₂ . In the embodiment of the present invention, the relative density is 80% or more, preferably 85% or more, and more preferably 90% or more. If the relative density is 80% or more, it can be said that it has sufficient density to be used as a sputtering target.

Moreover, in the embodiment of the present invention, in the X-ray diffraction analysis (XRD) of the oxide sputtering target, the XRD peak intensity attributable to the (-111) plane of the MoO ₂ phase is preferably set to I _MoO2 , and the XRD peak intensity I _MoO3 attributed to the (021) plane of the MoO3 phase, the XRD peak intensity ratio I _MoO2 /I _MoO3 is ₃ or more. As described above, the MoO ₂ phase has higher density and higher electrical conductivity than MoO ₃ , so it is preferable to exist in the form of MoO ₂ as much as possible.

The following defines the XRD peak intensity I _MoO2 ascribed to the ₍ -111) plane of the MoO2 phase. I _MoO2 =I _MoO2' /I _{MoO2 - BG} I _MoO2' : XRD peak intensity in the range of 25.5°≦2θ≦26.5° I _{MoO2 - BG} : 25°≦2θ≦25.5° and 26.5°≦2θ≦27° XRD average intensity in the range. The following defines the XRD peak intensity I _{MoO 3} ascribed to the (021) plane of the MoO ₃ phase. I _MoO3 =I _MoO3' /I _{MoO3 - BG} I _MoO3' : XRD peak intensity in the range of 27°≦2θ≦28° I _{MoO3 - BG} : 26.5°≦2θ<27° and 28°<2θ≦28.5° XRD average intensity in the range _The following defines the XRD peak intensity _IIn2Mo3O12 attributable to the ₍ 422) plane _of the _{In2Mo3O12 phase} . I _In2Mo3O12 =I _In2Mo3O12' /I _{In2Mo3O12 - BG} I _In2Mo3O12' : XRD peak intensity in the range of 32.5°≦2θ≦33.5° I _{In2Mo3O12 - BG} : between 32.0°≦2θ≦32.5° and 33.5°≦2θ≦34.0° XRD average intensity in the range Furthermore, the In ₂ Mo ₃ O ₁₂ phase is a phase formed by the reaction of MoO ₃ and In ₂ O ₃ .

Furthermore, the oxide sputtering target of the embodiment of the present invention preferably has a volume resistivity of 10 mΩ·cm or less. More preferably, it is 5 mΩ·cm or less, and still more preferably 1 mΩ·cm or less. Thereby, DC sputtering capable of high-speed film formation can be performed stably. As described above, in this oxide sputtering target, molybdenum oxide becomes MoO ₂ , and MoO ₂ is deficient in oxygen compared with MoO ₃ , so that the bulk resistance value can be lowered. In addition, the bulk resistance value fluctuates according to the content rate of Mo, and when the content rate of Mo increases, the resistance value tends to decrease.

Next, the manufacturing method of the oxide sputtering target which concerns on embodiment of this invention is demonstrated. Indium oxide (In ₂ O ₃ ) powder and molybdenum oxide (MoO ₂ ) powder were prepared as raw material powders, and these raw material powders were weighed so as to have a desired composition ratio, and a ball mill (grinding medium: ZrO ₂ , Al ₂ O ₃ , TiO ₂ , etc.) are pulverized and mixed. Next, the obtained mixed powder is hot-pressed sintered in a vacuum or in an atmosphere of a reducing gas (N ₂ , etc.), an inert gas (Ar, etc.) (sintering at the same time as molding, uniaxial pressure sintering), and a sintered body is produced. . Furthermore, when the raw material powders are MoO ₂ and In ₂ O ₃ , they continue to exist as MoO ₂ and In ₂ O ₃ without reacting after heat treatment and hot pressing. On the other hand, when the raw material powders are MoO ₃ and In ₂ O ₃ , a reaction occurs to generate In ₂ Mo ₃ O ₁₂ . Mo in the In ₂ Mo ₃ O ₁₂ is MoO ₃ and does not cause oxygen deficiency to MoO ₂ . The sintering temperature is preferably 950°C or higher and 1100°C or lower. If it is less than 950°C, a high-density sintered body cannot be obtained. On the other hand, if it exceeds 1100°C, it is unfavorable because of a variation in composition due to reduction, a decrease in density, and damage to a pressing member. In addition, the higher the ratio of Mo, the higher the sintering temperature needs to be. The pressing force is preferably set to 50 to 500 kgf/cm ² . Furthermore, the hot-pressing sintering system uses a carbon material that can withstand high-temperature pressurization, etc. for the pressurized member, so it cannot be implemented in the presence of oxygen. Thereafter, the obtained sintered body can be cut, ground, or the like into a target shape to produce a sputtering target.

For vacuum deposition, MoO ₃ (melting point: 795° C.) having a low melting point is more advantageous than MoO ₂ (melting point: 1100° C.) in order to evaporate the material. On the other hand, in order to use as a sputtering target, it is necessary to increase the density as described above, but In ₂ O ₃ cannot be sintered at a sintering temperature below the melting point of MoO ₃ , and it is difficult to increase the density. Therefore, by using MoO ₂ as the raw material powder, sintering in a vacuum, or in a reducing gas or inert gas environment can achieve an increase in density. Furthermore, in the case of using MoO ₃ as the raw material powder, MoO ₃ can be reduced to MoO ₂ for high temperature sintering by sintering in a vacuum, reducing gas, or in an inert gas environment, so it does not hinder the use of MoO ₃ as the raw material powder. . On the other hand, even when MoO ₂ is used as the raw material powder, even if the preformed compact is sintered in atmospheric conditions (normal pressure sintering), MoO ₂ is oxidized and melted into MoO ₃ , so that high Density of sintered bodies.

In the embodiment of the present invention, Examples and Comparative Examples are included, and the measurement method and the like can be set as shown below. [Composition analysis of sputtering target] Device: SPS3500DD manufactured by SII Company Method: ICP-OES (High Frequency Inductively Coupled Plasma Luminescence Analysis) [Measurement of volume resistivity] Method: constant current application method Device: Resistivity meter ∑-5+ manufactured by NPS Corporation Method: DC 4-probe method

[Determination of relative density] Relative density (%) = dimensional density/theoretical density × 100 Dimensional density: cut a part of the sputtering target, measure the size of the small piece to obtain the volume, and calculate from the weight and volume of the small piece. Theoretical density: Calculate the atomic ratio of each metal element by elemental analysis. From the atomic ratio, the In ₂ O ₃ conversion weight of In is set as a (wt%), and the MoO ₂ conversion weight of Mo is set as b (wt%), When the theoretical density of In ₂ O ₃ and MoO ₂ is d _In2 O 3 and d _MoO 2 , the theoretical density (g/cm ³ )=100/(a/d _In2 O 3 +b/d _MoO 2 ). In addition, the following values were used for the theoretical density of In ₂ O ₃ and MoO ₂ . d _{In 2 O 3} =7.18 g/cm ³ , d _MoO2 =6.44 g/cm ³

[X-ray diffraction analysis] Installation: SmartLab by Rigaku Tube: Cu-Kα ray Tube voltage: 40 kV Current: 30 mA Measurement method: 2θ-θ reflection method Scanning speed: 20.0°/min Sampling interval: 0.01° Example

Hereinafter, it demonstrates based on an Example and a comparative example. Furthermore, this embodiment is only an example, and is not limited by this example. That is, the present invention is limited only by the scope of the claims, and includes various changes other than the embodiments included in the present invention.

(Example 1) In ₂ O ₃ powder and MoO ₂ powder with a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=9:1 (atomic ratio) amount and mix. Next, the mixed powder was hot-pressed and sintered in an Ar (argon) atmosphere at a sintering temperature of 1050° C. and a surface pressure of 250 kgf/cm ² . After that, the sintered body is machined and finished into a sputtering target shape. The results obtained by measuring the density and volume resistivity of the obtained sputtering target are shown in Table 1. The relative density reached 97.5% and the volume resistivity was 0.23 mΩ·cm. Furthermore, as a result of analyzing the structure of the sputtering target using X-ray diffraction (XRD), the XRD peak intensity ratio I _MoO2 /I _MoO3 was 5.3. When sputtering was performed using this sputtering target, cracks and the like did not occur.

(Example 2) In ₂ O ₃ powder and MoO ₂ powder with a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=7:3 (atomic ratio) amount and mix. Next, the mixed powder was hot-pressed and sintered in an Ar (argon) atmosphere at a sintering temperature of 1000° C. and a surface pressure of 250 kgf/cm ² . After that, the sintered body was machined and finished into a sputtering target shape. The results obtained by measuring the density and volume resistivity of the obtained sputtering target are shown in Table 1. The relative density reached 87.1%, and the volume resistivity was 0.28 mΩ·cm. Furthermore, as a result of analyzing the structure of the sputtering target using X-ray diffraction (XRD), the XRD peak intensity ratio I _MoO2 /I _MoO3 was 10.1. When sputtering was performed using this sputtering target, cracks and the like did not occur.

(Example 3) In ₂ O ₃ powder and MoO ₂ powder with a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=7:3 (atomic ratio) amount and mix. Next, the mixed powder was hot-pressed and sintered in an Ar (argon) atmosphere at a sintering temperature of 1050° C. and a surface pressure of 250 kgf/cm ² . After that, the sintered body was machined and finished into a sputtering target shape. The results obtained by measuring the density and volume resistivity of the obtained sputtering target are shown in Table 1. The relative density reached 98.5% and the volume resistivity was 0.16 mΩ·cm. In addition, as a result of analyzing the structure of the sputtering target using X-ray diffraction (XRD), the XRD peak intensity ratio I _MoO2 /I _MoO3 was 11.3. When sputtering was performed using this sputtering target, cracks and the like did not occur.

(Example 4) In ₂ O ₃ powder and MoO ₂ powder with a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=5:5 (atomic ratio) amount and mix. Next, the mixed powder was hot-pressed and sintered in an Ar (argon) atmosphere at a sintering temperature of 1050° C. and a surface pressure of 250 kgf/cm ² . After that, the sintered body was machined and finished into a sputtering target shape. The results obtained by measuring the density and volume resistivity of the obtained sputtering target are shown in Table 1. The relative density reached 86.4%, and the volume resistivity was 0.15 mΩ·cm. Furthermore, as a result of analyzing the structure of the sputtering target using X-ray diffraction (XRD), the XRD peak intensity ratio I _MoO2 /I _MoO3 was 22.6. As a result of sputtering using a sputtering target, cracks and the like did not occur.

(Example 5) In ₂ O ₃ powder and MoO ₂ powder with a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=2:8 (atomic ratio) amount and mix. Next, the mixed powder was hot-pressed and sintered in an Ar (argon) atmosphere at a sintering temperature of 1100° C. and a surface pressure of 250 kgf/cm ² . After that, the sintered body was machined and finished into a sputtering target shape. The results obtained by measuring the density and volume resistivity of the obtained sputtering target are shown in Table 1. The relative density reached 81.7%, and the volume resistivity was 0.10 mΩ·cm. Furthermore, as a result of analyzing the structure of the sputtering target using X-ray diffraction (XRD), the XRD peak intensity ratio I _{MoO 2} /I _{MoO 3} was 55.6. As a result of sputtering using a sputtering target, cracks and the like did not occur.

(Comparative Example 1) In ₂ O ₃ powder and MoO ₂ powder having a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=7:3 (atomic ratio) amount and mix. Next, the mixed powder was hot-pressed and sintered in an Ar (argon) atmosphere at a sintering temperature of 900° C. and a surface pressure of 250 kgf/cm ² . After that, the sintered body was machined and finished into a sputtering target shape. The results obtained by measuring the density and volume resistivity of the obtained sputtering target are shown in Table 1. The relative density reached 67.6% and the volume resistivity was 57.22 mΩ·cm, which could not obtain the desired characteristics. In the case of such a low density, it is considered to be cracked at the time of sputtering.

(Comparative Example 2) In ₂ O ₃ powder and MoO ₃ powder having a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=7:3 (atomic ratio) amount and mix. Next, granulation was performed by adding polyvinyl alcohol (PVA) as a binder to obtain granulated powder. The granulated powder was filled in a mold and press-molded at 30 MPa to obtain a molded body. The compact was sintered at atmospheric pressure at a sintering temperature of 750°C (a temperature close to the melting point of MoO ₃ ) in the atmosphere. As a result, as shown in Table 1, the relative density was as low as 48.3%, and the processing of the sputtering target and the measurement of the volume resistivity could not be performed. When normal pressure sintering is performed in this way, it is difficult to increase the density. In addition, as a result of analyzing the structure of the sintered body (powder) using X-ray diffraction (XRD), the XRD peak intensity ratio I _MoO2 /I _MoO3 was 0.4, I _In2Mo3O12 was 6.4, and almost no MoO ₂ was formed. It was confirmed that _{I n2Mo3O12 was} generated.

(Comparative Example 3) In ₂ O ₃ powder and MoO ₃ powder with a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=7:3 (atomic ratio) amount and mix. Next, granulation was performed by adding polyvinyl alcohol (PVA) as a binder to obtain granulated powder. The granulated powder was filled in a mold and press-molded at 30 MPa to obtain a molded body. The compact was sintered at atmospheric pressure at a sintering temperature of 1150°C (close to the melting point of In ₂ Mo ₃ O ₁₂ ) in the atmosphere. As shown in Table 1, In ₂ Mo ₃ O _{1 2} was decomposed, MoO ₃ was evaporated, and the relative density was very low at 34.5%, making it impossible to process the sputtering target and measure the volume resistivity. In the case of performing normal pressure sintering at a high temperature in this way, it is also difficult to increase the density. In addition, as a result of analyzing the structure of the obtained sintered body (powder) by X-ray diffraction (XRD), the XRD peak intensity ratio I _{MoO 2} /I _MoO3 was 0.9, and almost no MoO ₂ was formed.

(Comparative Example 4) In ₂ O ₃ powder and MoO ₂ powder with a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=95:5 (atomic ratio) amount and mix. Next, the mixed powder was hot-pressed and sintered in an Ar (argon) atmosphere at a sintering temperature of 1000° C. and a surface pressure of 250 kgf/cm ² . As a result, the reduction of In ₂ O ₃ was rapid, and it was difficult to measure the density.

(Comparative Example 5) In ₂ O ₃ powder and MoO ₂ powder having a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=2:8 (atomic ratio) amount and mix. Next, the mixed powder was hot-pressed and sintered in an Ar (argon) atmosphere at a sintering temperature of 1050° C. and a surface pressure of 250 kgf/cm ² . After that, the sintered body was machined and finished into a sputtering target shape. The results obtained by measuring the density and volume resistivity of the obtained sputtering target are shown in Table 1. The relative density was 75.3%, and a high density could not be obtained. The higher the Mo content, the more it is necessary to increase the sintering temperature. As a result, it is considered that the reason for this is that the sintering temperature is insufficient relative to the Mo content of 80%.

(Comparative Example 6) In ₂ O ₃ powder and MoO ₂ powder with a purity of 3 N or more and a particle size of 0.5 to 10 μm were prepared, and these powders were weighed so that In:Mo=1:9 (atomic ratio) amount and mix. Next, the mixed powder was hot-pressed and sintered in an Ar (argon) atmosphere at a sintering temperature of 1100° C. and a surface pressure of 250 kgf/cm ² . After that, the sintered body was machined and finished into a sputtering target shape. The results obtained by measuring the density and volume resistivity of the obtained sputtering target are shown in Table 1. The relative density was 78.5%, and the desired density could not be obtained. In the case of such a low density, it is considered to be cracked at the time of sputtering.

[About constant temperature and humidity test] For each of the sputtering targets shown in the examples and comparative examples, sputtering was performed to form an oxide film on the substrate, and the formed film was placed in a constant temperature maintained at a temperature of 40°C and a humidity of 90%. In the humidifier, the change rates of transmittance and reflectance after 96 hours and 500 hours were investigated. The calculation of the change rate is as follows. Change rate of penetration rate = (penetration rate after test - penetration rate before test) / penetration rate before test × 100 Change rate of reflectance = (reflectivity after test - reflectivity before test) / reflectivity before test × 100 The results are shown in Table 2. As shown in Table 2, in Examples 1, 2, 4, and 5, the rate of change of transmittance and reflection were all below 30%. In addition, in the comparative example, since the relative density of the target was low, it was difficult to form a film by sputtering, so the film formation was not performed. For reference, the work function of each oxide film to be formed on the substrate is also shown in Table 2.

[Table 1]

產業上之可利用性[Table 2]

industrial availability

Since the oxide sputtering target of the embodiment of the present invention has a high density, the target does not crack (crack) during sputtering, and can be used at a practical and commercial level. The oxide sputtering target according to the embodiment of the present invention is particularly useful for forming transparent electrodes in light-emitting elements such as organic electroluminescent elements.

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Claims (6)

An oxide sputtering target, which contains MoO ₂ and In ₂ O ₃ , the Mo content satisfies 0.1≦Mo/(In+Mo)≦0.8 in terms of atomic ratio, and the relative density is 80% or more, and it belongs to When the XRD peak intensity of the (-111) plane of the MoO ₂ phase is set as I _MoO2 , and the XRD peak intensity of the (021) plane of the MoO ₃ phase is set as I _MoO3 , the XRD peak intensity ratio I _MoO2 /I _MoO3 is 3 or more; relative density (%)=size density/theoretical density×100. The oxide sputtering target as claimed in item 1 has a volume resistivity of 10mΩ. cm below. A method for producing an oxide sputtering target, which is the method for producing an oxide sputtering target according to claim 1 or 2, characterized in that: mixing indium oxide powder and molybdenum oxide powder, and mixing the mixed powder at 950 Hot press sintering is performed at a temperature of ℃ or more and 1100 ℃ or less. The method for producing an oxide sputtering target according to claim 3, wherein MoO ₂ powder is used as the molybdenum oxide powder. An oxide film, which is an oxide film formed by sputtering using the oxide sputtering target described in claim 1 or 2, characterized in that the visible light region (wavelength: 380-780nm) before and after constant temperature and humidity test The rate of change in the average reflectance is 30% or less. An oxide film, which is an oxide film formed by sputtering using the oxide sputtering target described in claim 1 or 2, characterized in that the visible light region (wavelength: 380-780nm) before and after constant temperature and humidity test The rate of change of the average penetration rate is less than 30%.