TWI700382B - Oxide thin film and oxide sintered body for sputtering target for manufacturing the thin film - Google Patents

Abstract

The present invention is an oxide thin film composed of Nb, Mo, and O, and is characterized in that the content ratio (atomic ratio) of Nb and Mo is 0.1≦Nb/(Nb+Mo)≦0.8, and O and metal ( The content ratio (atomic ratio) of Nb+Mo) is 1.5<O/(Nb+Mo)<2.0. In addition, the present invention is an oxide sintered body composed of Nb, Mo, and O, and is characterized in that the content ratio (atomic ratio) of Nb to Mo is 0.1≦Nb/(Nb+Mo)≦0.8, and O and The content ratio (atomic ratio) of metal (Nb+Mo) is 1.5<O/(Nb+Mo)<2.1, and the relationship between the XRD peak intensity I _MoO2 and the background intensity I _BG of the MoO ₂ phase attributable to the (-111) plane satisfies I _MoO2 /I _BG ＞3. The subject of the present invention is to provide an oxide thin film and an oxide sintered body for sputtering target suitable for the formation of the thin film. The oxide thin film has the following excellent characteristics: low reflectivity and transmittance, and excellent The light absorption ability is further dissolved in the etching solution, and it is easy to process. On the other hand, it has high weather resistance and is not easy to change with time.

Description

Oxide thin film and oxide sintered body for sputtering target for manufacturing the thin film

The present invention relates to an oxide thin film with light absorption capability and an oxide sintered body for sputtering target used to manufacture the thin film.

In liquid crystal displays, plasma displays, organic EL displays, touch panels, solar cells, etc., a transparent conductive film made of ITO (Indium Tin Oxide) is used as a wiring member. ITO has excellent permeability to visible light. Among oxides, because of its low resistivity, it is an excellent material as a wiring member. However, in the case of increasing the area of the display or the panel, the resistance becomes high and the problem of the increase of the area cannot be dealt with.

Based on the above situation, it has been studied to use a metal thin film with a lower resistivity instead of the ITO film as a wiring member. However, when it is used as a wiring member, the metal thin film reflects visible light, which reduces the visibility of the display or panel. In this regard, it is studied to form a film capable of absorbing reflected light in the vicinity of a metal thin film to suppress the reflection of light generated by the metal thin film and to improve visibility.

Regarding a film that reduces light reflection, for example, Patent Document 1 discloses the use of an oxide film containing any one of Cu and Fe, and any one of Ni and Mn as a film that reduces the metallic luster of the wiring pattern of the touch panel screen . In addition, Patent Document 2 discloses that a blackened layer containing oxygen, copper, nickel, and molybdenum is formed together with a wiring layer composed of copper foil or the like.

In Patent Documents 3 to 5, regarding the light absorbing layer used in the solar light absorbing layer or the black matrix layer of the liquid crystal display for utilizing solar heat, it is disclosed that there are two reasons for dispersing the metal as the absorbing component in the oxide matrix. Light absorbing layer composed of layers. In addition, it is stated that the thickness of the entire layer is in the range of 180-455 nm, and the visual transmittance of less than 1% and the visual reflectivity of less than 6% in the wavelength region of 380 to 780 nm.

In addition, as applications requiring light transmittance, reflectance, and film thickness, a phase shift type photomask is known. The phase shift type photomask is used for the purpose of improving the resolution by light interference. For the phase shift type mask film, according to the laser wavelength used, a specific film thickness, specific transmittance (about several %), and low reflectivity are required. Furthermore, in decorative applications, a film that reduces light reflection is also required.

Furthermore, Patent Document 6 describes a black matrix film with a Nb content of 1 to 35% by weight and the remainder is substantially Mo, and part or all of the film is composed of oxides, nitrides, and carbides. Any one or two or more of the compounds exist. However, in Patent Document 6, there is no specific disclosure regarding the content ratio of oxygen and the like, and it is completely unclear what degree of reflectance or transmittance can be obtained. Prior art literature Patent literature

Patent Document 1: Japanese Patent Application Publication No. 2016-160448 Patent Document 2: Japanese Patent Application Publication No. 2017-41115 Patent Document 3: Japanese Special Form No. 2016-504484 Patent Document 4: Japanese Special Publication No. 2016-502592 Patent Document 5: Japanese Special Form No. 2016-522317 Patent Document 6: Japanese Patent Laid-Open No. 2000-214308

[The problem to be solved by the invention]

The subject of the present invention is to provide an oxide film suitable for preventing light reflection and having both good etching processability and weather resistance and having light absorption ability, and an oxide sintering for sputtering target suitable for forming the above oxide film body. [Technical means to solve the problem]

The oxide film of the embodiment of the present invention has the following gist: it is composed of Nb, Mo, and O (oxygen), and the content ratio (atomic ratio) of Nb to Mo is 0.1≦Nb/(Nb+Mo)≦0.8, The content ratio (atomic ratio) of O to metal (Nb+Mo) is 1.5<O/(Nb+Mo)<2.0. In addition, the oxide sintered body of the embodiment of the present invention has the following gist: it is composed of Nb, Mo, and O (oxygen), and the content ratio (atomic ratio) of Nb to Mo is 0.1≦Nb/(Nb+Mo)≦0.8 , The content ratio (atomic ratio) of O to metal (Nb+Mo) is 1.5＜O/(Nb＋Mo)＜2.1, and the relationship between the XRD peak intensity I _MoO2 and the background intensity I _BG of the MoO ₂ phase attributable to the (-111) plane Satisfy I _MoO2 /I _BG ＞3. [Effects of Invention]

According to the present invention, it is possible to obtain an oxide film with light absorbing ability that has both good etching processability and weather resistance and is suitable for preventing light reflection. In addition, an oxide sintered body for sputtering target suitable for forming the above-mentioned oxide thin film can be obtained.

It is also considered to use a metal film as the light absorption film. However, in this case, the light absorption is relatively high and the transmittance can be reduced, but metal-specific metal reflection occurs, and it is difficult to reduce the reflectance. In addition, it is also considered to form an oxide film on the metal film, but the manufacturing process increases, which reduces the production efficiency. On the other hand, it is considered to use an oxide film as the light absorption film. In this case, since metal reflection does not occur, surface reflection is suppressed, but the light absorption is lower than that of the metal film, so the transmittance is increased, and the reflected light from the lower metal electrode is obvious, which makes the visibility Deteriorating situation.

In this respect, it is believed that among oxides, NbO ₂ or MoO ₂ based materials have relatively low transmittance of visible light and relatively low reflectivity, which are useful as light-absorbing films. However, in the case of the NbO ₂ film alone, the change over time is small and the weather resistance is excellent, but on the other hand, it is difficult to dissolve in etching solutions other than hydrogen fluoride (HF), and it is difficult to perform processing by etching. On the other hand, in the case of a single MoO ₂ film, even if it is a hydrogen peroxide (H ₂ O ₂ )-based etching solution for metal wiring, processing by etching can be realized, but there is a problem of poor weather resistance.

Based on the above, the oxide film of the embodiment of the present invention contains NbO ₂ , which has good weather resistance but is difficult to process by etching, and MoO ₂ , which can be processed by etching but has poor weather resistance, in a specific ratio. That is, the oxide thin film of the embodiment of the present invention is characterized in that it is composed of Nb, Mo, and O (oxygen), the content ratio (atomic ratio) of Nb and Mo is 0.1≦Nb/(Nb+Mo)≦0.8, and O and The content ratio (atomic ratio) of metal (Nb+Mo) is 1.5<O/(Nb+Mo)<2.0.

The oxide thin film of the embodiment of the present invention that satisfies the composition range of 0.1≦Nb/(Nb+Mo)≦0.8 has required optical properties, film resistance, and amorphousness. On the other hand, if Nb/(Nb+Mo) is less than 0.1, the required weather resistance cannot be obtained, and if Nb/(Nb+Mo) exceeds 0.8, the required etching processability cannot be obtained. Preferably, the content ratio of Nb to Mo is 0.1<Nb/(Nb+Mo)<0.5. In addition, if the content ratio O/(Nb+Mo) of O to metal (Nb+Mo) is 1.5 or less, the reflectance will increase, and if it is 2.0 or more, the transmittance will increase and the desired optical characteristics cannot be obtained. Therefore, it is set as the above-mentioned composition range.

In addition, the oxide film of the embodiment of the present invention preferably has an average reflectance of 30 for incident light in the visible light region (wavelength: 380~780 nm) when a film with a thickness of 100±10 nm is formed on a glass substrate. %the following. Here, the "average" reflectance refers to the reflectance measured every 5 nm in the above-mentioned wavelength region, and the average value is calculated. The reflectance includes the reflectance of light incident from the film side as shown in Fig. 1 (film side reflectance) and the reflectance of light incident from the glass substrate side as shown in Fig. 2 (substrate side reflectance). In the present invention, the reflectance only means the reflectance on the film side. In addition, the reflected light includes specular reflection light and diffuse reflection light, but in the present invention, it means the relative total light reflectivity of combining specular reflection light and diffuse reflection light.

In addition, the oxide film of the embodiment of the present invention is also preferably the average transmittance of incident light in the visible light region (wavelength: 380~780 nm) when a film with a thickness of 100±10 nm is formed on a glass substrate Less than 20%. Here, the so-called "average" transmittance refers to the value obtained by measuring the transmittance every 5 nm in the above-mentioned wavelength region and calculating the average value. If it is the reflectance and transmittance of this level, the light reflected from the metal wiring (copper foil, etc.) inside the display or panel can be fully absorbed, and the decrease in visibility can be suppressed. Furthermore, the low reflectance required for use as a phase shift photomask can be satisfied.

In addition, the above-mentioned transmittance is related to the film thickness of the oxide film. Generally, as the film thickness increases, the transmittance decreases. As described above, in the embodiment of the present invention, the transmittance when the thickness of the oxide film is 100 nm ± 10 nm or more is specified, and it is set to ± 10 nm because it is difficult to accurately form the film in reality. At 100 nm, even if the film thickness varies by ±10 nm (ie, 90 to 110 nm), the theoretical transmittance variation range is within ±1.3%. Even if the oxide film of the embodiment of the present invention considers the fluctuation range of the transmittance, the average transmittance satisfies 20% or less.

In addition, the surface resistivity of the oxide thin film in the embodiment of the present invention is preferably 1.0×10 ⁵ Ω/sq or less. In order to suppress the light reflection caused by the metal wiring, an oxide film that functions as a light absorption film is laminated adjacent to the metal wiring. However, when the resistivity of the oxide film is high, sufficient current cannot flow through the metal wiring. . Therefore, the surface resistivity of the oxide thin film is preferably set within the above range.

In addition, the oxide film of the embodiment of the present invention is preferably excellent in weather resistance, and the change rate of the average transmittance and average reflectance in the visible light region (wavelength: 380~780 nm) before and after the constant temperature and humidity test is 30% or less . In addition, the change rate of the surface resistivity before and after the constant temperature and humidity test is preferably 30% or less. Here, in the constant temperature and humidity test of the present invention, the oxide film sample formed on the substrate is placed in room A (temperature 40°C-humidity 90%) and room B (temperature 85°C-humidity 85%). After 120 hours, 500 hours, and 1000 hours, the transmittance, reflectance, and surface resistivity were compared with the measured values immediately after film formation, and the rate of change was studied.

Furthermore, in the embodiment of the present invention, the thickness of the oxide thin film is preferably 20 to 2000 nm. If the film thickness is less than 20 nm, the light absorption capacity may decrease. On the other hand, if the film thickness exceeds 2000 nm, the film formation takes longer than necessary, which is not good. However, the film thickness is ultimately determined by the device design, so as long as the light absorption capability is ensured, it is not limited to this film thickness.

In addition, the oxide thin film of the embodiment of the present invention is preferably amorphous (amorphous). Amorphous films have lower film stress than crystalline films, so film peeling or cracking during lamination is less likely to occur. Therefore, it is particularly suitable for flexible devices.

Next, the oxide sintered body of the embodiment of the present invention will be described in detail. The oxide sintered body of the embodiment of the present invention is characterized in that it is composed of Nb, Mo, and O (oxygen), the content ratio of Nb to Mo (atomic ratio) is 0.1≦Nb/(Nb+Mo)≦0.8, and O and metal The content ratio (atomic ratio) of (Nb+Mo) is 1.5<O/(Nb+Mo)<2.1, and the relationship between the XRD peak intensity I _MoO2 and the background intensity I _BG of the MoO ₂ phase attributable to the (-111) plane satisfies I _MoO2 / I _BG ＞3. The oxide sintered body having such characteristics can be used as a sputtering target.

The oxide sintered body of the embodiment of the present invention that satisfies the composition range of 0.1≦Nb/(Nb+Mo)≦0.8 and 1.5<O/(Nb+Mo)<2.1. The thin film obtained by sputtering film formation has the required optical properties , Film resistance, amorphous. In the above-mentioned oxide sintered body, when the content ratio of O to metal (Nb+Mo) is 1.5<O/(Nb+Mo)<2.1, regarding the thin film sputtered using the oxide sintered body (sputtering target), Even when oxygen is not introduced during sputtering, the content ratio of O to metal (Nb+Mo) is within the range of 1.5<O/(Nb+Mo)<2.0, and the desired film characteristics can be obtained.

The relationship between the XRD peak intensity I _MoO2 and the background intensity I _BG attributable to the (-111) plane of the MoO ₂ phase of the oxide sintered system of the embodiment of the present invention satisfies I _MoO2 /I _BG > 3. If the above XRD peak intensity ratio If I _MoO2 /I _BG ＞3 is satisfied, most of the molybdenum (Mo) in the sintered body is in the form of MoO _2. When this oxide sintered body is used, in the thin film formed by sputtering, Obtain the required optical properties.

In addition, the relative density of the oxide sintered body of the embodiment of the present invention is preferably 80% or more. If the relative density is more than 80%, it can be used as a sputtering target to withstand practicality. More preferably, it is 85% or more. Furthermore, the volume resistivity of the oxide sintered body of the embodiment of the present invention is preferably 100 mΩ·cm or less. By reducing the volume resistivity, film formation by DC sputtering can be realized. Compared with RF sputtering, DC sputtering has a faster film forming speed, excellent sputtering efficiency, and can increase productivity. Furthermore, depending on the manufacturing conditions, RF sputtering may be performed. In this case, the film formation speed is also increased.

The oxide sintered body of the embodiment of the present invention can be produced as follows, for example. The raw material powders of NbO ₂ powder and MoO ₂ powder are weighed and mixed so as to have the desired composition. The raw material powder preferably has a purity of 99.9% or more and a particle size (D50) of 0.5-10 μm. As a mixing method, it is preferable to pulverize and mix using a ball mill or the like. As the raw material powder, it is also considered to use Nb ₂ O ₅ powder and Mo powder, but since the sintering temperature of Nb ₂ O ₅ and Mo are very different, it is difficult to increase the density. Next, the mixed powder is hot pressed (uniaxial pressure sintering) for 5-10 hours under the conditions of 1100°C or more and 1200°C or more and a pressure of 250 MPa or more in an Ar environment. Thereby, an oxide sintered body composed of Nb, Mo, and O with a relative density of over 80% can be obtained. In addition, the obtained oxide sintered body can be processed into a sputtering target by cutting, grinding, etc.

The oxide thin film of the embodiment of the present invention can be produced in the following manner, for example. The NbO ₂ sputtering target and MoO ₂ sputtering target are set in the sputtering device, and sputtering is performed at the same time, and a mixed film of NbO ₂ and MoO ₂ is formed on the substrate. At this time, the film composition can be changed by changing the respective sputtering power during sputtering. Alternatively, the sputtering target produced by the above method is set in a sputtering device, and sputtering is performed, and a mixed film of NbO ₂ and MoO ₂ is formed on the substrate. At this time, the composition of the sputtering target is not exactly the same as the composition of the film, but becomes a composition close to it. Since the composition of the target and the composition of the film are related, the conditions can be determined to grasp the composition of the target that can obtain the desired film composition. In addition, the amount of oxygen in the film can also be adjusted by adjusting the oxygen flow rate introduced during sputtering. <Film formation conditions> Sputtering device: ANELVA SPL-500 Substrate temperature: Room temperature (substrate is not heated) Film formation environment: Ar or Ar+O ₂ Air pressure: 0.2~2.0 Pa Gas flow rate: 50~100 sccm Power: 100~1000 W (DC, RF) Substrate: EagleXG manufactured by Corning (ϕ4 mm×0.7 mm)

The evaluation method of the oxide thin film and the oxide sintered body of the embodiment of the present invention includes examples and comparative examples, and is described below. (About transmittance and reflectance) Device: manufactured by SHIMADZU, spectrophotometer UV-2450 Measurement sample: Samples formed with a film thickness of 100±10 nm on a glass substrate with a thickness of 0.7 mm, and an unfilmed glass substrate test methods: (Reflectivity) Use the relative total light reflectivity of the integrating sphere (reference sample; mirror mirror). The reflectance of light incident from the film side (film side reflectance) includes not only the reflectance from the film surface, but also the reflectance from the glass substrate (surface) at the interface with the film, and the reflectance from the back of the glass substrate . The reflectance of light incident from the glass substrate side (substrate side reflectance) includes the reflectance from the surface of the glass substrate and the reflectance from the film at the interface with the glass substrate. (Transmittance) The relative transmittance using the glass substrate as the reference sample.

(About the composition of the film) Device: JXA-8500F manufactured by JEOL Method: EPMA (Electron Probe Micro Analyzer) Accelerating voltage: 5~10 keV Irradiation current: 1.0×10 ^-8 ～1.0～10 ^-9 A to probe With a needle diameter of 10 μm, select 5 points of the smooth film-forming part that has no dirt attached and cannot be seen on the substrate surface for point analysis, and calculate the average composition.

(About the surface resistance of the film) Device: resistivity tester manufactured by NPS Company Σ-5+ Method: DC four probe method

(Regarding the non-crystalline nature of the film) Determine the presence or absence of the diffraction peak generated by the X-ray diffraction of the film-forming sample. When the diffraction peak due to the film material is not observed in the measurement under the following conditions, it is judged to be an amorphous film. Here, the absence of diffraction peaks means that when the maximum peak intensity of 2θ=10°~60° is set to I _max , and the average peak intensity of 2θ=20°~25° is set to I _BG , I _max /I _BG ＜5. In addition, in the table, as a criterion for determining the amorphous property, the case that satisfies I _max /I _BG <5 is set as ○, and the case that is not satisfied is ×. Device: Smart Lab manufactured by Rigaku Company Tube ball: Cu-Kα tube Voltage: 40 kV Current: 30 mA Measurement method: 2θ-θ reflection method Scanning speed: 20°/min Sampling interval: 0.02° Measuring range: 10°~ 60° test sample: film-forming sample on glass substrate (EagleXG) (film thickness above 100 nm)

(About film thickness measurement) Stylus Step Gauge Dektak8 made by Veeco Method: Determine the film thickness from the step difference between the film-forming surface and the non-film-forming surface of the glass substrate after film formation.

(Regarding the etching processability of the film) The etching liquid is a hydrogen peroxide (H ₂ O ₂ ) chemical liquid. In the etching judgment, the case where the etching rate is fast is set as ○, the case where the etching rate is slow is set as △, and the case where the etching rate is almost insoluble is set as ×.

(About the composition of the sintered body) Device: SPS3500DD manufactured by SII Company Method: ICP-OES (High Frequency Inductively Coupled Plasma Luminescence Analysis Method)

(About the relative density of the sintered body) Measure the size (using calipers) and weight of the sintered body and calculate the size density. From the size density and the theoretical density of the sintered body, calculate the relative density (%) = size density/theoretical density × 100. The theoretical density is calculated from the blending ratio of each oxide and the theoretical density of each. When the weight of NbO ₂ is set to a (wt%) and the weight of MoO ₂ is set to b (wt%), the theoretical density = 100/(a/5.90 + b/6.44) The theoretical density of NbO ₂ : 5.90 g/cm ³ 、Theoretical density of MoO ₂ : 6.44 g/cm ³

(About XRD analysis of sintered body) Device: Smart Lab manufactured by Rigaku Company Tube ball: Cu-Kα tube Voltage: 40 kV Current: 30 mA Measuring method: 2θ-θ reflection method Scanning speed: 20°/min Sampling interval: 0.02° Measurement range: 10°~60° Sample measurement position: Sputtering surface Furthermore, the following defines the XRD peak I _MoO2 of the MoO ₂ phase attributable to the (-111) surface. I _MoO2 = I _MoO2' /I _{MoO2 - BG} I _MoO2' : XRD peak intensity in the range of 25.5°≦2θ≦26.5° I _{MoO2 -BG} : XRD average intensity in the range of 19.5°≦2θ<20.5°.

(About the volume resistivity of the sintered body) Device: resistivity tester manufactured by NPS Company Σ-5+ Method: DC four probe method Example

Hereinafter, description will be made based on Examples and Comparative Examples. 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 patent application, and includes various modifications other than the embodiments included in the present invention.

(Examples 1-1 to 1-6, Comparative Examples 1-1 to 1-2) The NbO ₂ target (ϕ6 inch) and MoO ₂ target (ϕ6 inch) were set in the sputtering device (ANELVA SPL-500), and By simultaneous sputtering, a mixed film of NbO ₂ and MoO ₂ is formed on the glass substrate (EagleXG, ϕ4 inch). The film forming conditions were as described above, and as shown in Table 1, the power of each target during sputtering was changed to produce a film with the composition described in Table 1. Further, Comparative Examples 1-1 only based sputtering target MoO ₂ and MoO ₂ film by forming, only Comparative Example 1-2 based sputtering target and NbO ₂ NbO ₂ film by deposition. Then, for each oxide thin film obtained by changing the composition, the transmittance, front reflectance/back reflectance, and surface resistivity immediately after film formation (room temperature) were measured, and the etching properties were further studied. The results are shown in Table 1.

[Table 1]

As shown in Table 1, the average transmittance and average reflectance of oxide films (Examples 1-1 to 1-6) with the content ratio (atomic ratio) of Nb and Mo satisfying 0.1≦Nb/(Nb+Mo)≦0.8 All are low, showing excellent light absorption ability, in addition, low film resistance, excellent etching processability, and amorphous. Examples 1-1 to 1-5 have particularly fast etching rates.

Secondly, in order to investigate the weather resistance, the oxide films formed on the substrate were placed in room A (temperature 40°C-humidity 90%) and room B (temperature 85°C-humidity 85%) under various conditions. The changes in transmittance, front reflectance/back reflectance, and surface resistance after hours, 500 hours and 1000 hours are studied. The results are shown in Table 2.

[Table 2]

As shown in Table 2, the transmittance, reflectance and surface resistance of the oxide film (Examples 1-2~1-5) are all less than 30% with time (rate of change), which is excellent in weather resistance. membrane. On the other hand, the oxide film containing only Mo (Comparative Example 1-1) has poor weather resistance, and the transmittance etc. increase significantly over time. In addition, the oxide thin film containing only Nb (Comparative Example 1-3) is almost insoluble in the etching solution.

(Examples 2-1 to 2-4, Comparative Example 2-1) As raw material powders, NbO ₂ powder and MoO ₂ powder with a purity of 99.9% or more and a particle size of 0.5 to 10 μm were prepared so as to be specified as described in Table 3. The powders are weighed based on the ratio, and mixed and crushed using a ball mill. Next, the obtained mixed powder was subjected to hot press sintering in an argon atmosphere at a sintering temperature of 1200°C and a surface pressure of 250 kgf/cm ² to produce an oxide sintered body. Furthermore, only the weighing ratio was adjusted, and other than that, mixing, pulverization, and sintering were performed under the same conditions. Table 3 shows the evaluation results of the obtained oxide sintered body. As shown in Table 3, the relationship between the XRD peak intensity I _MoO2 of the MoO ₂ phase attributable to the (-111) plane and the background intensity I _BG of all the examples satisfies I _MoO2 /I _BG ＞3, and the relative density is 80 % Or more, and the volume resistivity is 100 mΩ·cm or less. On the other hand, in Comparative Example 2-1, the XRD peak intensity ratio of the MoO ₂ phase was 1.7, and MoO ₂ disappeared. Next, the oxide sintered bodies obtained in Examples and Comparative Examples were processed into sputtering targets, and sputtering films were formed using the targets. Table 3 shows the optical properties of the sputtered film obtained. The average transmittance and average reflectance of the film obtained by sputtering the oxide sintered body obtained in the examples are low, and show excellent light absorption ability.

[產業上之可利用性][table 3]

[Industrial availability]

The oxide film of the embodiment of the present invention has the following excellent characteristics: low transmittance and reflectivity, excellent light absorption ability, and can be processed by etching, have high weather resistance, and are not easy to change with time. Furthermore, since the oxide sintered body of the embodiment of the present invention has a relatively high density, it can be used as a sputtering target. The oxide film of the embodiment of the present invention is very useful as a light absorbing film used for liquid crystal displays, plasma displays, organic EL displays, touch panels, solar cells, etc., to prevent the reflection of light generated by metal wiring, and It is very useful as a mask material and decorative purposes.

no

Figure 1 is an explanatory diagram of the reflectance of light incident from the film side (film side reflectance). Fig. 2 is an explanatory diagram of the reflectance of light incident from the glass substrate side (substrate side reflectance).

Claims (13)

An oxide film composed of Nb, Mo, and O, characterized in that the content ratio (atomic ratio) of Nb and Mo is 0.1≦Nb/(Nb+Mo)≦0.8, and O and metal (Nb The content ratio (atomic ratio) of +Mo) is 1.5<O/(Nb+Mo)<2.0. The oxide film described in claim 1 has an average reflectance of 30% or less in the visible light region (wavelength: 380 to 780 nm). The oxide film described in claim 1 has an average transmittance of 20% or less in the visible light region (wavelength: 380 to 780 nm). The oxide film described in claim 2 has an average transmittance of 20% or less in the visible light region (wavelength: 380 to 780 nm). The oxide thin film according to any one of claims 1 to 4 has a surface resistivity of 1.0×10 ⁵ Ω/sq or less. The oxide film according to any one of claims 1 to 4, wherein the change rate of the average reflectance in the visible light region (wavelength: 380 to 780 nm) before and after the constant temperature and humidity test is 30% or less. The oxide film according to any one of claims 1 to 4, wherein the rate of change in the average transmittance of the visible light region (wavelength: 380 to 780 nm) before and after the constant temperature and humidity test is 30% or less. The oxide film according to any one of claims 1 to 4, wherein the change rate of the surface resistivity before and after the constant temperature and humidity test is 30% or less. The oxide thin film according to any one of claims 1 to 4, which has a film thickness of 20 to 2000 nm. The oxide thin film according to any one of claims 1 to 4, which is amorphous. An oxide sintered body composed of Nb, Mo, and O, characterized in that the content ratio (atomic ratio) of Nb and Mo is 0.1≦Nb/(Nb+Mo)≦0.8, and O and metal (Nb The content ratio (atomic ratio) of +Mo) is 1.5<O/(Nb+Mo)<2.1, and the XRD peak intensity of the MoO ₂ phase attributable to the (-111) plane I The relationship between _MoO2 and the background intensity I _BG satisfies I _MoO2 /I _BG >3. The oxide sintered body described in claim 11 has a relative density of 80% or more. The oxide sintered body described in claim 11 or 12 has a volume resistivity of 100 mΩ. cm below.

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