TWI537404B - Oxide sintered body, oxide sputtering target, and method for producing conductive oxide film and oxide sintered body - Google Patents

Description

Oxide sintered body, oxide sputtering target, conductive oxide film, and method for producing oxide sintered body

The present invention relates to an oxide sintered body, an oxide sputtering target, a conductive oxide film, and a method for producing an oxide sintered body, and more particularly to an amorphous conductive oxidation suitable for forming a high transmittance and a high refractive index. An oxide sintered body sputtering target of the film.

In the case where visible light is used in various optical devices such as a display or a touch panel, the material used must be transparent, and it is particularly preferable to have high transmittance in the entire visible light region. Further, in various optical devices, light loss may occur due to a difference in refractive index between the formed film material or the interface with the substrate, and as a method for improving such optical loss, introduction is performed to adjust the refractive index or optical film thickness. A method of optically adjusting a film. Since the refractive index obtained by the optical adjustment film differs depending on the structure of various devices, it is necessary to have a wide refractive index. In addition, conductivity may be required depending on the place where it is used.

In addition, the characteristics required for the optical adjustment film are mainly refractive index or extinction coefficient (high transmittance), but in recent years, in addition to refractive index or extinction coefficient (high transmittance), in order to further improve the performance, Coexistence of a plurality of characteristics such as conductivity, etching property (etchable), water resistance, and amorphous film is also required. In order to coexist such a plurality of characteristics, it is difficult to achieve a single oxide film, and it is necessary to form a composite oxide film in which a plurality of oxides are mixed. Particularly, it is effective as a composite oxide film in which an oxide of a ternary system or more is mixed.

As a material which is generally transparent and electrically conductive, ITO (indium oxide-tin oxide), IZO (indium oxide-zinc oxide), GZO (gallium oxide-zinc oxide), AZO (alumina-zinc oxide), etc. are known. . However, the refractive index of these materials at a wavelength of 550 nm is in the range of about 1.95 to 2.05, and cannot be used as a high refractive index material for optical adjustment (n > 2.05). Further, in order to increase the transmittance, ITO must be heated at the time of film formation or after annealing, so that it is difficult to use a plastic substrate that cannot be heated or used for an organic EL device. Further, since IZO absorbs on the short-wavelength side, there is a problem that it becomes a yellow film.

In order to solve such a problem, the present inventors have succeeded in forming a conductive amorphous thin film having a high transmittance and a high refractive index by using an adjusted oxide sintered body sputtering target (Patent Document 1). However, after continuous research, it has been found that the film containing the obtained composition in the composition range becomes a composition range of the crystallized film, and when it is used as a flexible device or must be protected from moisture, such crystallization The film sometimes does not fit. Further, depending on the use of the film, a crystallized film may be preferred. In Patent Document 2, in the case of a thin film transistor, it is considered that the amorphous film cannot obtain a stable film. In the past, even if it is known that the transparent conductive film has a wide composition range (for example, Patent Document 3), the crystallinity of the film is not particularly recognized.

Patent Document 1: Japan's Special Wish 2013-220805

Patent Document 2: International Publication WO2012/153507

Patent Document 3: Japanese Patent No. 4940068

Patent Document 4: International Publication WO2010/058533

An object of the present invention is to provide a sintered body which can be obtained A conductive film having high transmittance and high refractive index of visible light. Since this film has a high transmittance and a high refractive index, it is suitable as a film for an optical device such as a display or a touch panel, in particular, a film for optical adjustment. Further, an object of the present invention is to provide a sputtering target which has a high relative density and a low volume resistivity, and can perform DC sputtering. The object of the present invention is to improve the characteristics of the optical device, reduce the cost of the device, and greatly improve the film forming properties.

In order to solve the problem, the inventors of the present invention have earned the following findings: by using the material system shown below, a conductive film having high transmittance and high refractive index can be obtained, and good results can be ensured. The optical characteristics and stable film formation by DC sputtering can improve the characteristics of the optical device using the film and improve productivity.

The inventors have provided the following invention based on this finding.

1) An oxide sintered body composed of indium (In), titanium (Ti), zinc (Zn), tin (Sn), and oxygen (O), and satisfies the following relationship: In the case of the content of In relative to Ti, the number of atoms The ratio is 3.0 ≦In/Ti≦5.0, and the content of Zn and Sn relative to In and Ti is 0.2 ≦(Zn+Sn)/(In+Ti)≦1.5 in terms of atomic ratio, and the content of Zn relative to Sn is The atomic ratio is 0.5 ≦ Zn / Sn ≦ 7.0.

2) The oxide sintered body according to the above 1), which has a relative density of 90% or more.

3) The oxide sintered body according to the above 1) or 2), which has a volume resistivity of 10 Ωcm or less.

4) A film comprising indium (In), titanium (Ti), zinc (Zn), tin (Sn), and oxygen (O) satisfying the following relationship: the content of In relative to Ti is in atomic ratio 3.0≦In/Ti≦5.0, the content of Zn and Sn relative to In and Ti is 0.2≦(Zn+Sn)/(In+Ti)≦1.5 in atomic ratio, and the atomic ratio of Zn to Sn is relative to Sn. Calculated as 0.5 ≦ Zn / Sn ≦ 7.0.

5) The film according to the above 4), which has a refractive index at a wavelength of 550 nm of 2.05 or more.

6) The film according to the above 4) or 5), which has an extinction coefficient of 0.05 or less at a wavelength of 405 nm.

The film according to any one of the above 4) to 6), which has a volume resistivity of 1 M?cm or less.

The film according to any one of the above 4), which is amorphous.

(9) A method for producing an oxide sintered body, which is the method for producing the oxide sintered body according to any one of the above items 1) to 3), wherein the raw material is used in an inert gas or a vacuum atmosphere at 900 ° C or higher and 1300 ° C or lower. After the powder is subjected to pressure sintering or pressure-molding of the raw material powder, the formed body is subjected to normal pressure sintering at 1000 ° C or more and 1500 ° C or less in an inert gas or a vacuum atmosphere.

According to the present invention, by using the material system described above, a conductive film (especially an amorphous film) having high transmittance and high refractive index can be obtained, ensuring desired optical characteristics, and ensuring good etching property. And high temperature and high humidity resistance. Further, the present invention has an excellent effect of improving the characteristics of various optical devices, reducing the equipment cost, and greatly improving the productivity by increasing the film formation speed.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a graph showing the X-ray diffraction spectrum of a film formed by sputtering of the present invention.

The oxide sintered body of the present invention is characterized in that it is composed of indium (In), titanium (Ti), zinc (Zn), tin (Sn), and oxygen (O), and satisfies the following relationship: In content relative to Ti The atomic ratio is 3.0 ≦In/Ti≦5.0, and the content of Zn and Sn relative to In and Ti is 0.2 ≦(Zn+Sn)/(In+Ti)≦1.5 in terms of atomic ratio, and Zn is relative to Sn. The content is 0.5 ≦ Zn / Sn ≦ 7.0 in terms of atomic ratio.

By using a sputtering target composed of the oxide sintered body, an amorphous conductive oxide film having high transmittance and high refractive index can be obtained. Further, the material of the present invention contains indium (In), titanium (Ti), zinc (Zn), tin (Sn), and oxygen (O) as constituent elements, but also contains unavoidable impurities in the material.

A film of In-Ti-Zn-O (indium oxide-titanium oxide-zinc oxide) has a problem in that it is easily crystallized in a composition region having good conductivity and, in the case of sputtering, oxygen is introduced. The characteristics of high transmittance and low resistance are opposite, and it is difficult to adjust characteristics. When the content of ZnO is large, conductivity is mainly caused by oxygen deficiency of ZnO, but this oxygen deficiency exhibits conductivity (low resistance) and light absorption (low transmittance) occurs. reason. However, by adding a predetermined ratio of tin (Sn) to the system, it is desirable to form a homologous structure (crystallization) of IZTO, but it does not crystallize under the rapid cooling film formation by sputtering, and can be amorphized. Further, since such tin addition can simultaneously achieve high transmittance and low resistance, it is easy to adjust characteristics. This is considered to be because the above-described conductivity mechanism is changed by the addition of tin.

Further, the addition of a predetermined proportion of tin has a secondary effect of imparting good etching properties or high temperature and high humidity resistance.

In the present invention, the content of In with respect to Ti satisfies the relationship of 3.0 ≦In/Ti≦5.0 in atomic ratio. If it exceeds this range, the desired optical characteristics and electrical characteristics cannot be obtained. In particular, if the atomic ratio is less than 3.0, the high electrical resistance is obtained. On the other hand, if the atomic ratio is more than 5.0, There is a problem that the light absorption becomes large and a high refractive index cannot be obtained. However, even in the case where it exceeds the above range, if the content of In with respect to Ti is 2.5 Å in/Ti ≦ 7.0 in terms of atomic ratio, relatively good optical characteristics and electrical characteristics can be obtained.

Further, in the present invention, the total content of Zn and Sn is made relative to In and Ti. The total content satisfies the relationship of 0.1 ≦(Zn+Sn)/(In+Ti)≦3.0 in atomic ratio. If it exceeds this range, it is not preferable because the desired optical characteristics and electrical characteristics cannot be obtained. In particular, if the atomic ratio (Zn + Sn) / (In + Ti) is less than 0.1, there is a problem of high resistance. On the other hand, if the atomic ratio (Zn + Sn) / (In + Ti) exceeds 3.0 There is a problem that the film will crystallize and the light absorption will become large. However, even if it exceeds the above range, if the total content of Zn and Sn is 0.1 ≦(Zn+Sn)/(In+Ti) ≦3.5 in terms of the atomic ratio of the total content of In and Ti, Relatively good optical and electrical properties are obtained.

Further, in the present invention, the content of Zn with respect to Sn satisfies the relationship of 0.5 ≦ Zn / Sn ≦ 7.0 in atomic ratio. If it exceeds this range, it is not preferable because the desired optical characteristics and electrical characteristics cannot be obtained. In particular, if the atomic ratio Zn/Sn is less than 0.5, the resistance is high. On the other hand, if the atomic ratio Zn/Sn exceeds 7.0, there is a problem that the film crystallizes and the light absorption occurs. Become bigger. However, even when it exceeds the above range, if the content of Zn relative to Sn is 0.1 ≦ Zn/Sn ≦ 10.0 in atomic ratio, relatively good optical characteristics and electrical characteristics can be obtained.

The sintered body of the present invention is characterized in that indium (In), titanium (Ti), zinc (Zn) and tin (Sn) satisfy the above atomic ratio, but the content of each component is preferably In content of In ₂ O ₃ The conversion is 5 to 50 mol%, the Ti content is 4 to 40 mol% in terms of TiO ₂ , the Zn content is 4 to 60 mol% in terms of ZnO, and the Sn content is 5 to 40 mol% in terms of SnO. A sintered body target having such a composition range is effective for a conductive film which is excellent in optical characteristics or electrical characteristics. Further, in the above, the content of each metal in the sintered body is described in terms of oxide. This is because the blending of the raw materials can be easily adjusted with an oxide. Further, in the usual analysis apparatus, the content of the oxide cannot be specified, but the content (% by weight) of each metal element can be specified. Therefore, when it is desired to specify the respective compositions of the target, the content of each metal element may be specified by assuming the respective oxides and then converted (mol%).

When the sintered body of the present invention is used as a sputtering target, the relative density is preferably 90% or more. The lifting density has the effect of improving the uniformity of the sputter film and suppressing generation of particles during sputtering. The relative density of 90% or more can be achieved by the method for producing a sintered body of the present invention to be described later.

Further, in the case of using the sintered body of the present invention as a sputtering target, the volume resistivity is preferably 10 Ωcm or less. Film formation can be achieved by DC sputtering by reducing the volume resistivity. Compared to RF sputtering, DC sputtering provides faster film formation, excellent sputtering efficiency, and increased throughput. In addition, RF sputtering is sometimes performed depending on the manufacturing conditions, and even in this case, the film formation speed is increased.

The film produced by the sputtering of the present invention is characterized by being amorphous. The amorphous film is particularly suitable as a material for a flexible device or a material having a low water permeability (protecting moisture). Further, the film of the present invention can have a refractive index of 2.05 or more at a wavelength of 550 nm. Further, in the film of the present invention, the extinction coefficient at a wavelength of 405 nm can be made 0.05 or less. Further, the film of the present invention can have a volume resistivity of 1 M?cm or less. Such a conductive film having a high refractive index and a high transmittance is useful as an optical device for a display or a touch panel as a film for optical adjustment. In particular, the present invention can be said to be a material system which is highly suitable for obtaining desired optical characteristics because a high refractive index film having an extinction coefficient at a wavelength of 405 nm of 0.05 or less and a short wavelength region in the visible light region can be obtained.

In the sintered body of the present invention, it is preferable to press-sinter the raw material powder composed of the oxide powder of each constituent metal at 900 ° C or higher and 1300 ° C or lower in an inert gas atmosphere or a vacuum atmosphere, or press-form the raw material powder. The formed body is subjected to normal pressure sintering at 1000 ° C or more and 1500 ° C or less in an inert gas or a vacuum atmosphere. If the pressure sintering is less than 900 ° C and the sintering at normal pressure is less than 1000 ° C, a sintered body having a high density cannot be obtained. On the other hand, if the pressure sintering exceeds 1300 ° C and the normal pressure sintering exceeds 1500 ° C, It is not good because the composition is deviated or the density is lowered due to evaporation of the material. Moreover, if pressure sintering is performed at more than 1300 ° C, it may react with a carbon mold. The pressurizing pressure is preferably from 150 to 500 kgf/cm ² . Further, in Patent Document 4, in order to precipitate the In ₂ O ₃ phase in which both Zn and Sn are solid-solved, the second-stage sintering is performed to lower the volume resistivity, but in the present invention, due to oxygen deficiency Since the conductivity is imparted, such two-stage sintering is not performed.

In order to further increase the density, the raw material powder is weighed and mixed, and the mixed powder is pre-fired (synthesized), and then finely pulverized, and it is effective to use the finely pulverized powder as a powder for sintering. By performing pre-synthesis and fine pulverization in this manner, a uniform fine raw material powder can be obtained, and a dense sintered body can be produced. The particle diameter after the fine pulverization is an average particle diameter of 5 μm or less, and preferably an average particle diameter of 2 μm or less. Further, the calcination temperature is preferably 800 ° C or more and 1200 ° C or less. By setting such a range, sinterability can be improved and density can be further increased.

The evaluation methods and the like in the present invention (including the examples and comparative examples) are as follows.

(about composition)

Device: SII company manufactures SPS3500DD

Method: ICP-OES (high frequency inductively coupled plasma luminescence analysis method)

(about density measurement)

Inch measurement (caliper), weight measurement

(about relative density)

Calculated using the theoretical density described below.

Relative density (%) = inch density / theoretical density × 100

The theoretical density is calculated by converting the blend ratio of the oxides of the respective metal elements.

The weight in terms of In ₂ O ₃ of In is a (wt%), and the weight in terms of TiO _{2 of} Ti is b (wt%).

The weight in terms of Zn ZnO is c (wt%), and when the weight in terms of Sn Sn ₂ is d (wt%), the theoretical density is 100/(a/7.18+b/4.26+c/5.61+d/7.0)

Moreover, the following values were used for the oxide conversion density of each metal element.

In ₂ O ₃ : 7.18 g/cm ³ , TiO ₂ : 4.26 g/cm ³ , ZnO: 5.61 g/cm ³ , SnO ₂ : 7.0 g/cm ³ ,

(About volume resistivity, surface resistivity)

Device: manufactured by NPS Resistivity meter Σ-5+

Method: DC 4 probe method

Further, the surface resistivity of the film was measured, and the volume resistivity was calculated by the following formula.

Volume resistivity (Ωcm) = surface resistivity (Ω/sq) × film thickness (cm)

(about refractive index, extinction coefficient)

Device: manufactured by Shimadzu Corporation, spectrophotometer UV-2450

Method: Calculate from transmittance and surface reflectance

(About film formation method and conditions)

Device: ANELVA SPL-500

Substrate: 4inch

Substrate temperature: room temperature

(about crystallinity evaluation)

A sample of 500 to 1000 nm is formed on a glass substrate by X-ray diffraction (device: Ultima IV, Cu-K α ray, tube voltage: 40 kV, current: 30 mA, 2 θ-θ reflection method, Scanning speed: 8.0 ^° / min, sampling interval: 0.02 ^° ) for analysis. The crystallinity was evaluated by the ratio of the maximum peak intensity I _MAX detected by 2 θ = 10 ^° to 60 ^° with respect to the background intensity I _BG ratio I _MAX /I _BG . In addition, regarding the background intensity, the average intensity of the region where the peaks on the low-angle side and the high-angle side of I _{MAX are} not observed (range: 2 θ = 1 ^° ~ 10 ^° ). For example, I _BG = {(an average intensity of 10 ^° ~ 20 ^° ) + (an average intensity of 50 ^° ~ 60 ^° )}/2 is obtained. The determination of the amorphous film is a case where I _MAX /I _BG ≦10 is determined as an amorphous film.

(about etching property)

The film formation sample was judged to be ○ by etching with an etching liquid (various acids), and it was judged to be × when it was impossible to etch or excessively dissolve.

(About high temperature and high humidity)

After 48 hours of storage at a temperature of 800 ° C and a humidity of 80%, optical constants and resistance measurements were carried out, and when the difference in characteristics was less than 10%, it was judged as ○, and when it was 10% or more, it was judged as ×. .

[Examples]

Hereinafter, it demonstrates based on an Example and a comparative example. In addition, this embodiment is merely an example and is not limited by this illustration. 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 invention.

(Example 1)

In ₂ O ₃ powder, TiO ₂ powder, ZnO powder, and SnO ₂ powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. Next, the mixed powder was calcined in the air at a temperature of 1050 ° C, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, and after drying, sieved with a mesh of 150 μm. . Then, the finely pulverized powder was subjected to hot press sintering under the conditions of a temperature of 1100 ° C and a pressure of 250 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape. Further, the results of analyzing the composition of the sputtering target were confirmed to be the same as the blending ratio of the raw material powder.

Next, sputtering was performed using the above-mentioned finished target having a diameter of 6 Å. The sputtering conditions were a DC sputtering, a sputtering power of 500 W, an Ar gas pressure of 2 vol% of oxygen, and a film thickness of 5000 Å. In addition, substrate heating and sputtering after sputtering are not performed.

The above results are shown in Table 1. As shown in Table 1, the sputtering target had a relative density of 97.5% and a volume resistivity of 6.3 m Ω cm, and stable DC sputtering was possible. Then, the film deposited by sputtering has a refractive index of 2.11 (wavelength: 550 nm), an extinction coefficient of 0.03 (wavelength: 405 nm), and a volume resistivity of 4.9 × 10 ^-1 Ωcm, thereby obtaining a high refractive index and high transmittance conductivity. Sex film. Further, as a result of the crystallization evaluation, as shown in Fig. 1, it was confirmed that I _MAX /I _BG = 4 and it was an amorphous film.

(Example 2)

In ₂ O ₃ powder, TiO ₂ powder, ZnO powder, and SnO ₂ powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. Next, the mixed powder was calcined in the air at a temperature of 1050 ° C, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, and after drying, sieved with a mesh of 150 μm. . Then, the finely pulverized powder was subjected to hot press sintering under the conditions of a temperature of 1150 ° C and a pressure of 250 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape. Next, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished target having a diameter of 6 Å.

The above results are shown in Table 1. As shown in Table 1, the sputtering target had a relative density of 97.7% and a volume resistivity of 4.4 m Ω cm, enabling stable DC sputtering. Then, the film which was sputtered and formed into a film had a refractive index of 2.11 (wavelength: 550 nm), an extinction coefficient of 0.02 (wavelength: 405 nm), and a volume resistivity of 9.8 Ωcm, whereby a conductive film having a high refractive index and a high transmittance was obtained. Further, as a result of the crystallization evaluation, as shown in Fig. 1, it was confirmed that I _MAX /I _BG = 4 and it was an amorphous film.

(Example 3)

In ₂ O ₃ powder, TiO ₂ powder, ZnO powder, and SnO ₂ powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. Next, the mixed powder was calcined in the air at a temperature of 1050 ° C, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, and after drying, sieved with a mesh of 150 μm. . Then, the finely pulverized powder was subjected to hot press sintering under the conditions of a temperature of 1150 ° C and a pressure of 250 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape. Next, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished target having a diameter of 6 Å.

The above results are shown in Table 1. As shown in Table 1, the sputtering target has a relative density of 99.5% and a volume resistivity of 3.7 m Ω cm, and stable DC sputtering can be performed. Then, the film deposited by sputtering has a refractive index of 2.10 (wavelength: 550 nm), an extinction coefficient of 0.02 (wavelength: 405 nm), and a volume resistivity of 3.8 × 10 ² Ωcm, thereby obtaining high refractive index and high transmittance conductivity. membrane. Further, as a result of crystallization evaluation, it was confirmed that I _MAX /I _BG =4, which is an amorphous film.

(Example 4)

In ₂ O ₃ powder, TiO ₂ powder, ZnO powder, and SnO ₂ powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. Next, the mixed powder was calcined in the air at a temperature of 1050 ° C, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, and after drying, sieved with a mesh of 150 μm. . Then, the finely pulverized powder was subjected to hot press sintering under the conditions of a temperature of 1150 ° C and a pressure of 250 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape. Next, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished target having a diameter of 6 Å.

The above results are shown in Table 1. As shown in Table 1, the sputtering target has a relative density of 100.9% and a volume resistivity of 1.5 m?cm, and stable DC sputtering can be performed. Then, the film deposited by sputtering has a refractive index of 2.11 (wavelength: 550 nm), an extinction coefficient of 0.02 (wavelength: 405 nm), and a volume resistivity of 1.6 × 10 ³ Ωcm, thereby obtaining high refractive index and high transmittance conductivity. membrane. Further, as a result of crystallization evaluation, it was confirmed that I _MAX /I _BG =4, which is an amorphous film.

(Example 5)

In ₂ O ₃ powder, TiO ₂ powder, ZnO powder, and SnO ₂ powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. Next, the mixed powder was calcined in the air at a temperature of 1050 ° C, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, and after drying, sieved with a mesh of 150 μm. . Then, the finely pulverized powder was subjected to hot press sintering under the conditions of a temperature of 1150 ° C and a pressure of 250 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape. Next, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished target having a diameter of 6 Å.

The above results are shown in Table 1. As shown in Table 1, the sputtering target had a relative density of 100.3% and a volume resistivity of 1.7 m?cm, and stable DC sputtering was possible. Then, the film deposited by sputtering has a refractive index of 2.11 (wavelength: 550 nm), an extinction coefficient of 0.02 (wavelength: 405 nm), and a volume resistivity of 3.6 × 10 ³ Ωcm, thereby obtaining high refractive index and high transmittance conductivity. membrane. Further, as a result of crystallization evaluation, it was confirmed that I _MAX /I _BG =4, which is an amorphous film.

(Comparative Example 1)

In ₂ O ₃ powder, TiO ₂ powder, and SnO ₂ powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. In addition, no ZnO powder was added. Next, the mixed powder was subjected to hot press sintering under the conditions of a temperature of 1050 ° C and a pressure of 350 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape.

Next, sputtering was performed using the above-mentioned finished target having a diameter of 6 Å. However, the volume resistivity of the target (sintered body) of Comparative Example 1 was as high as more than 500 kΩcm, and DC sputtering could not be performed. Therefore, sputtering is performed using RF sputtering. The conditions such as power are the same as those for DC sputtering. As a result, the volume resistivity of the film formed by sputtering was more than 1 MΩcm, which was high resistance, and a desired conductive film was not obtained.

(Comparative Example 2)

In ₂ O ₃ powder, TiO ₂ powder, and ZnO powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. In addition, no SnO ₂ powder was added. Next, the mixed powder was subjected to hot press sintering under the conditions of a temperature of 1050 ° C and a pressure of 350 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape. Next, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished target having a diameter of 6 Å. As a result, the thin film formed by sputtering, as shown in FIG. 1, I _MAX /I _BG =101, does not become an amorphous film, and the extinction coefficient exceeds 0.05 (wavelength 405 nm), and light is generated in a low-wavelength region. Absorbed, the desired high transmittance film was not obtained.

(Comparative Example 3)

In ₂ O ₃ powder, TiO ₂ powder, and ZnO powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. In addition, no SnO ₂ powder was added. Next, the mixed powder was subjected to hot press sintering under the conditions of a temperature of 1150 ° C and a pressure of 250 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape. Next, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished target having a diameter of 6 Å. As a result, the volume resistivity of the film formed by sputtering was more than 1 MΩcm, which was high resistance, and a desired conductive film was not obtained. Further, as a result of the evaluation of crystallization, it was confirmed to be an amorphous film.

(Comparative Example 4)

In ₂ O ₃ powder, TiO ₂ powder, ZnO powder, and SnO ₂ powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. In addition, the content of the doped synthetic In relative to Ti is more than specified. Next, the mixed powder was subjected to hot press sintering under the conditions of a temperature of 1050 ° C and a pressure of 350 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape. Next, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished target having a diameter of 6 Å. As a result, the extinction coefficient of the film formed by sputtering was more than 0.05 (wavelength 405 nm), and a film having a desired transmittance was not obtained.

(Comparative Example 5)

In ₂ O ₃ powder, TiO ₂ powder, ZnO powder, and SnO ₂ powder were prepared, and the powders were blended at the blending ratios shown in Table 1, and mixed. In addition, the total content of Zn and Sn doped with respect to In and Ti is more than specified. Next, the mixed powder was subjected to hot press sintering under the conditions of a temperature of 1050 ° C and a pressure of 350 kgf / cm ² in an argon atmosphere. Then, the sintered body is machined and finished into a target shape. Next, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished target having a diameter of 6 Å. As a result, the film formed by sputtering was not an amorphous film, and the extinction coefficient exceeded 0.05 (wavelength: 405 nm), and light absorption was caused in a low-wavelength region, and a desired high-transmittance film was not obtained.

[Industrial availability]

The film formed by sputtering according to the present invention has the following effects: forming a part of the structure of the optical adjustment film or the optical disk in the display or the touch panel, in terms of transmittance, refractive index, and electrical conductivity, Has excellent characteristics.

Further, since the sputtering target composed of the sintered body of the present invention has a low volume resistivity value and a high density, stable DC sputtering can be performed. Further, it has a remarkable effect that the sputtering controllability as a feature of the DC sputtering can be made easy, the film formation speed can be improved, and the sputtering efficiency can be improved. Moreover, when the film is formed, the particles generated during the sputtering can be reduced, and the quality of the film can be improved.

Claims (11)

An oxide sintered body for forming an optical adjustment film, which is composed of indium (In), titanium (Ti), zinc (Zn), tin (Sn), and oxygen (O), and satisfies the following relationship: In content relative to Ti The atomic ratio is 3.0 ≦In/Ti≦5.0, and the content of Zn and Sn relative to In and Ti is 0.5 ≦(Zn+Sn)/(In+Ti)≦1.5 in terms of atomic ratio, and Zn is relative to Sn. The content is 0.5 ≦ Zn / Sn ≦ 7.0 in terms of atomic ratio. The oxide sintered body for forming an optical adjustment film according to the first aspect of the invention is characterized in that the relative density is 90% or more. The oxide sintered body for forming an optical adjustment film according to claim 1 or 2, which has a volume resistivity of 10 Ωcm or less. An optical adjustment film composed of indium (In), titanium (Ti), zinc (Zn), tin (Sn), and oxygen (O), and satisfies the following relationship: In the case of the content of In relative to Ti, the atomic ratio is 3.0≦In/Ti≦5.0, the content of Zn and Sn relative to In and Ti is 0.5≦(Zn+Sn)/(In+Ti)≦1.5 in atomic ratio, and the atomic ratio of Zn to Sn Calculated as 0.5 ≦ Zn / Sn ≦ 7.0. The optical adjustment film of claim 4, which has a refractive index at a wavelength of 550 nm of 2.05 or more. The optical adjustment film of claim 4, wherein the extinction coefficient at a wavelength of 405 nm is 0.05 or less. The optical adjustment film of claim 5, wherein the extinction coefficient at a wavelength of 405 nm is 0.05 or less. The optical adjustment film according to any one of claims 4 to 7, which has a volume resistivity of 1 M?cm or less. The optical adjustment film of any one of claims 4 to 7 which is amorphous. The optical adjustment film of claim 8 is amorphous. A method for producing an oxide sintered body, which is a method for producing a sintered body according to any one of claims 1 to 3, wherein the raw material powder is added at 900 ° C or more and 1300 ° C or less in an inert gas or a vacuum atmosphere. After press-sintering or press-forming the raw material powder, the formed body is subjected to normal pressure sintering at 1000 ° C or more and 1500 ° C or less in an inert gas or a vacuum atmosphere.