TWI608111B - Oxide sintered body, oxide sputtering target, high refractive index conductive oxide film, and oxide sintered body manufacturing method - Google Patents

Description

Oxide sintered body, oxide sputtering target, conductive film of high refractive index, and method for producing oxide sintered body

The present invention relates to an oxide sintered body, an oxide sputtering target, a high refractive index conductive oxide film, and a method for producing an oxide sintered body, and more particularly to a sintered body having a low volume resistance and capable of DC sputtering. A plating target and a high refractive index film produced using the same.

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 in the entire region of the visible light region, it is particularly desirable to have high transmittance. Further, in various optical devices, there is a case where light loss due to a refractive index difference is formed at an interface with a film material or a substrate which is formed, and a method for improving the light loss is introduced to adjust a refractive index or an optical film. Thick optical adjustment film method. The refractive index required for the optical adjustment film varies depending on the configuration of the various devices, and therefore a wide range of refractive indices is required. Also, there is a need for electrical conductivity depending on the location in which it is used.

Generally, as a transparent and electrically conductive material, ITO (indium oxide-tin oxide), IZO (indium oxide-zinc oxide), GZO (gallium oxide-zinc oxide), AZO (alumina-zinc oxide), and the like are known ( Patent Documents 1 to 3). However, these materials are used in a range of 1.95 to 2.05 with a refractive index at a wavelength of 550 nm, and cannot be used as a high refractive index material (n>2.05) or a low refractive index material (n<1.95) for optical adjustment. . Further, in order to increase the transmittance, the ITO must be heated at the time of film formation or annealed after film formation, so that it is difficult to use until Problems such as the use of plastic substrates or organic EL devices that cannot be heated. Moreover, since IZO has absorption on the short-wavelength side, there is a problem that it becomes a yellow film.

Patent Document 1: Japanese Special Open 2007-008780

Patent Document 2: Japanese Special Open 2009-184876

Patent Document 3: Japanese Special Open 2007-238375

The object of the present invention is to provide a high penetration of visible light. A sintered body of a conductive film having a high refractive index. Since this film has a high transmittance and a high refractive index, it is useful as a film for an optical device such as a display or a touch panel, particularly as a film for optical adjustment. Further, an object of the present invention is to provide a sputtering target which has a relatively high relative density and a low bulk resistance and can perform DC sputtering. It is an object of the present invention to improve the characteristics of an optical device, reduce the cost of equipment, and greatly improve the characteristics of film formation.

In order to solve the above problems, the inventors of the present invention have diligently studied and found the following. Insight: By using the material system disclosed later, a conductive film having high transmittance and high refractive index can be obtained, and good optical characteristics can be ensured, and further, film formation can be stably performed by DC sputtering, and can be improved. The characteristics of the optical device using the film are improved and productivity is improved.

The present invention provides the following invention based on the above findings:

1) A sintered body comprising indium (In), titanium (Ti) or chromium (Cr), zinc (Zn), tin (Sn), and oxygen (O), and contains 2 in terms of In ₂ O ₃ ~65 mol% of In contains 2 to 65 mol% of Ti or Cr in terms of TiO ₂ or Cr ₂ O ₃ , and the atomic ratio of In is A (at%), and the atomic ratio of Ti or Cr is B (at When the atomic ratio of %), Zn or Sn is C (at%), 0.5 ≦ A/B ≦ 5, and 0 < C / (A + B) < 10.

2) As described above 1) sintered body according to claim 28, wherein to In ₂ O ₃ in terms of containing 2 ~ 30mol% of In, respectively, calculated as TiO ₂ or Cr ₂ O ₃ in terms of containing 3 ~ 30mol% of Ti or Cr, 40 mol% or more of Zn or Sn is contained in terms of ZnO or SnO ₂ , respectively.

3) The sintered body according to the above 1) or 2), wherein 0 < C / (A + B) < 5.

The sintered body according to any one of the above 1) to 3, wherein the sintered body has a relative density of 90% or more.

5) The sintered body according to any one of the above 1) to 4, wherein the sintered body has a volume resistance of 10 Ω. Below cm.

6) A film comprising indium (In), titanium (Ti) or chromium (Cr), zinc (Zn), tin (Sn), and oxygen (O), and contains 2~ in terms of In ₂ O ₃ 65 mol% of In contains 2 to 65 mol% of Ti or Cr in terms of TiO ₂ or Cr ₂ O ₃ , and the atomic ratio of In is A (at%), and the atomic ratio of Ti or Cr is B (at%). When the atomic ratio of Zn or Sn is C (at%), 0.5 ≦ A/B ≦ 5, and 0 < C / (A + B) < 10.

7) The film according to the above 6), wherein the refractive index at a wavelength of 550 nm is 2.05 or more.

8) The film according to the above 6) or 7), wherein the extinction coefficient at a wavelength of 450 nm is 0.05 or less.

9) The film according to any one of the above 6), wherein the specific resistance is 1 MΩcm or less.

(10) A method for producing a sintered body according to any one of the above items 1 to 5, wherein the raw material powder is added at 900 ° C or more and 1500 ° C or less in an inert gas or a vacuum atmosphere. After the pressure sintering or the raw material powder is press-formed, 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, a material system as described above is employed, whereby high wear can be obtained A conductive film having a high transmittance and a high refractive index, and ensuring desired optical characteristics. Further, the present invention has an excellent effect of improving the characteristics of various optical devices, reducing the cost of equipment, and improving the productivity of the film forming speed.

The present invention is characterized in that it consists of indium (In), titanium (Ti) or chromium (Cr), zinc (Zn), tin (Sn), and oxygen (O), and contains 2 in terms of In ₂ O ₃ . ~65 mol% of In contains 2 to 65 mol% of Ti or Cr in terms of TiO ₂ or Cr ₂ O ₃ , and the atomic ratio of In is A (at%), and the atomic ratio of Ti or Cr is B (at When the atomic ratio of %), Zn or Sn is C (at%), 0.5 ≦ A/B ≦ 5, and 0 < C / (A + B) < 10. Thereby, a conductive film having a high transmittance and a high refractive index can be obtained.

Further, in the present invention, indium (In), titanium (Ti) or chromium (Cr), and zinc (Zn), tin (Sn), and oxygen (O) are used as constituent elements, but in the material, Contains unavoidable impurities.

The material system of the present invention comprises the formula: M ¹ M ² O ₃ (M ³ O) _m (M ¹ : first component, M ² : second component, M ³ : third component, m is 1 or more natural The homologous compound represented by the number of the homologous compound is a material having a homologous structure and is a high refractive index material, and the first component is In or Fe, and the second component is Ti, Cr, In, Fe or Sn. The three components are Zn, Sn, Cu, Mn, Fe or Co. However, Fe, Cu, Mn, and Co are less likely to cause absorption in the visible light region due to a smaller band gap.

Therefore, it was decided to use In as the first component. Further, the third component determines the use of Zn or Sn. Further, in order to increase the refractive index and to use In or Sn as the second component, it was decided to use Ti. Or Cr as the second component.

In the present invention, the content of In is set to 2 to 65 mol% in terms of In ₂ O ₃ . Further, it is preferably 2 to 30 mol%. Further, the content of Ti or Cr is set to 3 to 65 mol% in terms of TiO ₂ conversion or Cr ₂ O ₃ conversion. Further, it is preferably 3 to 30 mol%. The content of Zn or Sn which is the third component can be derived from the atomic ratio of In and Ti or Cr and the above-mentioned C/(A+B), but it is preferably set to 40 mol in terms of ZnO or SnO. %the above. Thereby, a conductive film having a desired high transmittance and a high refractive index can be realized.

In the present invention, the atomic ratio of A/B is set to 0.5 ≦A/B ≦5. If this is exceeded The range is not good enough to obtain the desired optical properties. In particular, when A/B is 5 or more, there is a problem that the content of the high refractive index material (Ti or Cr) is decreased and the refractive index is lowered. Further, in the present invention, the atomic ratio of C/(A+B) is set to 0 < C / (A + B) < 10, and further preferably set to 0 < C / (A + B) < 5. If it exceeds this range, the content of the high refractive index material is reduced as described above, and the problem of the desired high refractive index cannot be obtained.

When the sintered body of the present invention is used as a sputtering target, it is preferably set to be relatively dense. More than 90%. The increase in density has an effect of improving the uniformity of the sputtering film and suppressing the generation of particles at the time of sputtering. The relative density of 90% or more can be achieved by the method for producing a sintered body of the present invention described below.

Moreover, when the sintered body of the present invention is used as a sputtering target, it is preferably set to have a bulk resistance of 10 Ω. Below cm. By the drop in bulk resistance, film formation can be performed by DC sputtering. Compared with RF (radio frequency) sputtering, DC sputtering has a faster deposition rate and excellent sputtering efficiency, which can increase the output. Further, depending on the manufacturing conditions, there is also a case where RF sputtering is performed, and in this case, the film formation speed can also be increased.

The film produced by the sputtering of the present invention can be folded at a wavelength of 550 nm. The rate of incidence is 2.05 or more. Further, the film of the present invention can have an extinction coefficient of 0.05 or less at a wavelength of 450 nm. Further, the film of the present invention can achieve a specific resistance of 1 MΩ. Below cm. As a film for optical adjustment, such a conductive film having a high refractive index and a high transmittance is useful for an optical device such as a display or a touch panel. In particular, the present invention can be obtained as a film having an extinction coefficient of a wavelength of 450 nm of 0.01 or less and a high refractive index which is hardly absorbed in a short-wavelength region, and thus can be said to be an excellent material system for obtaining desired optical characteristics.

In the above composition range, the film of the present invention exists as a crystallized film and Become an amorphous film. Further, there is also a state in which the partially crystallized film coexists in both. In the present invention, the crystallinity of such a film is not particularly limited, and the composition can be adjusted depending on the desired crystallinity. Further, the crystallinity (crystallized film, amorphous film, or partially crystallized film) of the film can be evaluated by the presence or absence of the diffraction peak of the X-ray diffraction method.

The sintered body of the present invention can be obtained by an inert gas atmosphere or a vacuum atmosphere The raw material powder composed of the oxide powder of each constituent metal is subjected to pressure sintering (hot pressing) or by press molding the raw material powder, and then the molded body is produced by normal pressure sintering. At this time, the sintering temperature is preferably set to 900 ° C or more and 1500 ° C or less. If it is less than 900 ° C, a sintered body having a high density cannot be obtained. On the other hand, if it exceeds 1500 ° C, a composition variation or a decrease in density due to evaporation of the material may occur, which is not preferable.

Example

Hereinafter, description will be made based on examples and comparative examples. Furthermore, this embodiment is an example after all, 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 invention.

The evaluation methods and the like in the examples and comparative examples are as follows.

(for composition)

Device: SPS3500DD manufactured by SII

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

(for relative density)

The size of the sintered body was measured by a vernier caliper, and the density of the sintered body was calculated from the volume and the measured weight.

As shown below, the theoretical density was obtained by multiplying the monomer density of the oxide of the raw material by the mixing mass ratio and summing the obtained values. Further, the density of the oxide sintered body was divided by the theoretical density and multiplied by 100 to determine the relative density.

Theoretical density = Σ { (cell density of each oxide × mixed mass ratio) + (monomer density of each oxide × mixed mass ratio +...)

Relative density = {(density of sintered body) / (theoretical density)} × 100

(for body resistance [specific resistance, sheet resistance])

Device: manufactured by NPS Co., Ltd. Resistivity meter Σ-5+

Method: DC 4 probe method

(for refractive index, extinction coefficient)

Device: manufactured by SHIMADZU, spectrophotometer UV-2450

Method: Calculate self-transmission rate and surface reflectance

(for film formation methods and conditions)

Device: ANELVA SPL-500

Substrate: φ 4inch

Substrate temperature: room temperature

(Example 1)

In ₂ O ₃ powder, TiO ₂ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, this mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1,150 ° C and a pressure of 250 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape.

Then, sputtering was performed using the above-mentioned finished 6-inch diameter target. The sputtering conditions were as follows: DC sputtering, sputtering power of 500 W, and Ar gas pressure of 0 to 2 vol% of oxygen, 0.5 Pa, and film formation to a film thickness of 5000 Å. Further, the substrate is not heated or the annealing after sputtering is performed.

The results are shown in Table 1. As shown in Table 1, the sputtering target system has a relative density of 98.9% and a bulk resistance of 2.9×10 ^-3 Ω. Cm, achieving stable DC sputtering. Further, the film deposited by sputtering has a refractive index of 2.10 (wavelength 550 nm), an extinction coefficient of 0.01 (wavelength: 450 nm), and a resistance value of 2.3 × 10 ^-2 Ω. Above cm, a conductive film having a high refractive index and a high transmittance is obtained. Further, regarding the resistance value, the amount of oxygen at the time of sputtering may vary slightly, and the resistance value may increase as the amount of oxygen increases. Therefore, the lower limit value is described.

(Example 2)

In ₂ O ₃ powder, TiO ₂ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, this mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1,150 ° C and a pressure of 250 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. The result is that the sputtering target reaches a relative density of 100.3% and a bulk resistance of 8.7×10 ^-3 Ω. Cm, achieving stable DC sputtering. Moreover, the refractive index of the film formed by sputtering is 2.15 (wavelength 550 nm), the extinction coefficient is less than 0.01 (wavelength 450 nm), and the resistance value is 1.8×10 ⁺² Ω. Above cm, a conductive film having a high refractive index and a high transmittance is obtained.

(Example 3)

In ₂ O ₃ powder, TiO ₂ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, this mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1,100 ° C and a pressure of 250 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. The result is that the sputtering target reaches a relative density of 99.5% and a bulk resistance of 3.5×10 ^-3 Ω. Cm, achieving stable DC sputtering. Moreover, the refractive index of the film formed by sputtering is 2.22 (wavelength 550 nm), the extinction coefficient is less than 0.01 (wavelength 450 nm), and the resistance value is 1.2×10 ⁺² Ω. Above cm, a conductive film having a high refractive index and a high transmittance is obtained.

(Example 4)

In ₂ O ₃ powder, Cr ₂ O ₃ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, this mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1,100 ° C and a pressure of 350 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. The result is that the sputtering target system reaches a relative density of 100.2% and a bulk resistance of 8.0×10 ^-4 Ω. Cm, achieving stable DC sputtering. Further, the film deposited by sputtering has a refractive index of 2.10 (wavelength 550 nm), an extinction coefficient of 0.02 (wavelength: 450 nm), and a resistance value of 2.8 × 10 ^-2 Ω. Above cm, a conductive film having a high refractive index and a high transmittance is obtained.

(Example 5)

In ₂ O ₃ powder, TiO ₂ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, this mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1,150 ° C and a pressure of 250 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. The result is that the sputtering target reaches a relative density of 100.1% and a bulk resistance of 9.6×10 ^-4 Ω. Cm, achieving stable DC sputtering. Moreover, the film deposited by sputtering has a refractive index of 2.12 (wavelength 550 nm), an extinction coefficient of less than 0.01 (wavelength of 450 nm), and a resistance value of 8.7×10 ^-3 Ω. Above cm, a conductive film having a high refractive index and a high transmittance is obtained.

(Example 6)

In ₂ O ₃ powder, TiO ₂ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, this mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1,100 ° C and a pressure of 250 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. The result is that the sputtering target reaches a relative density of 99.8% and a bulk resistance of 8.4×10 ^-4 Ω. Cm, achieving stable DC sputtering. Moreover, the refractive index of the film formed by sputtering is 2.05 (wavelength 550 nm), the extinction coefficient is less than 0.01 (wavelength 450 nm), and the resistance value is 9.3×10 ^-3 Ω. Above cm, a conductive film having a high refractive index and a high transmittance is obtained.

(Example 7)

In ₂ O ₃ powder, Cr ₂ O ₃ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, the mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1,150 ° C and a pressure of 350 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. The result is that the sputtering target reaches a relative density of 98.2% and a bulk resistance of 5.2×10 ^-3 Ω. Cm, achieving stable DC sputtering. Further, the film formed by sputtering has a refractive index of 2.07 (wavelength 550 nm), an extinction coefficient of 0.03 (wavelength: 450 nm), and a resistance value of 3.6 × 10 ^-2 Ω. Above cm, a conductive film having a high refractive index and a high transmittance is obtained.

(Example 8)

In ₂ O ₃ powder, TiO ₂ powder, and SnO ₂ powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, after the mixed powder was press-formed, the formed body was sintered at room temperature under an argon atmosphere at a temperature of 1300 °C. Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. The result is that the sputtering target reaches a relative density of 97.8% and a bulk resistance of 8.7×10 ^-2 Ω. Cm, achieving stable DC sputtering. Further, the film formed by sputtering has a refractive index of 2.08 (wavelength 550 nm), an extinction coefficient of 0.01 (wavelength: 450 nm), and a resistance value of 3.1 × 10 ¹ Ω. Above cm, a conductive film having a high refractive index and a high transmittance is obtained.

(Comparative Example 1)

In ₂ O ₃ powder, Fe ₂ O ₃ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, the mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1050 ° C and a pressure of 350 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. As a result, the film having a sputtered film had an extinction coefficient of 0.16 (wavelength: 450 nm), and absorption of light was generated in a low-wavelength region, and a desired high transmittance film could not be obtained.

(Comparative Example 2)

In ₂ O ₃ powder, TiO ₂ powder, and CuO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. Then, the mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1050 ° C and a pressure of 350 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. As a result, the extinction coefficient of the film formed by sputtering is 0.2 or more (wavelength: 450 nm), and light absorption occurs in a low-wavelength region, and a desired high-transmittance film cannot be obtained.

(Comparative Example 3)

In ₂ O ₃ powder, TiO ₂ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. At this time, the atomic ratio of In/Ti was increased to 8.0. Then, this mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1,150 ° C and a pressure of 250 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. As a result, the refractive index of the film formed by sputtering was 2.01 (wavelength: 550 nm), and the refractive index was lowered, and the desired high refractive index film could not be obtained.

(Comparative Example 4)

In ₂ O ₃ powder, TiO ₂ powder, and ZnO powder were prepared, and the powders were blended and mixed in the blending ratios shown in Table 1. At this time, the atomic ratio of Zn/(In+Ti) was increased to 15. Then, the mixed powder was subjected to hot press sintering under the conditions of an argon atmosphere at a temperature of 1050 ° C and a pressure of 250 kgf / cm ² . Thereafter, the sintered body is machined and finished into a target shape. Then, sputtering was carried out under the same conditions as in Example 1 using the above-mentioned finished 6-inch diameter target. As a result, the refractive index of the film formed by sputtering was 2.02 (wavelength: 550 nm), and the refractive index was lowered, and the desired high transmittance film could not be obtained.

Industrial use

The film formed by the sputtering of the present invention forms part of the structure of the optical adjustment film or the optical disk in the display or the touch panel, and has extremely excellent characteristics in transmittance, refractive index, and electrical conductivity. effect.

Further, since the sputtering target system composed of the sintered body of the present invention has a low resistance value and a high density, stable DC sputtering can be performed. Further, it has a remarkable effect that the sputtering control property of the DC sputtering is easy, the film formation speed is increased, and the sputtering efficiency can be improved. Moreover, the particles generated at the time of sputtering at the time of film formation can be reduced, and the quality of the film can be improved.

Claims (13)

A sintered body composed of indium (In), titanium (Ti) or chromium (Cr), zinc (Zn), tin (Sn), and oxygen (O), and contains 2 to 65 mol in terms of In ₂ O ₃ . % of In contains 2 to 65 mol% of Ti or Cr in terms of TiO ₂ or Cr ₂ O ₃ , and the atomic ratio of In is A (at%), and the atomic ratio of Ti or Cr is B (at%). When the atomic ratio of Zn or Sn is C (at%), 0.5 ≦ A/B ≦ 5, and 0 < C / (A + B) < 10. The patent application range of the sintered body, Paragraph 1, wherein, in order to In ₂ O ₃ in terms of containing 2 ~ 30mol% of In, respectively, calculated as TiO ₂ or Cr ₂ O ₃ in terms of containing 3 ~ 30mol% of Ti or Cr, 40 mol% or more of Zn or Sn is contained in terms of ZnO or SnO ₂ , respectively. The sintered body of claim 1, wherein 0 < C / (A + B) < 5. The sintered body of claim 2, wherein 0 < C / (A + B) < 5. The sintered body according to any one of claims 1 to 4, which has a relative density of 90% or more. The sintered body of any one of claims 1 to 4 has a volume resistance of 10 Ω. Below cm. For example, the sintered body of claim 5 has a volume resistance of 10 Ω. Below cm. A film comprising indium (In), titanium (Ti) or chromium (Cr), and zinc (Zn) or tin (Sn), and oxygen (O), and contains 2 to 65 mol% in terms of In ₂ O ₃ In, each of Ti contains 2 to 65 mol% of Ti or Cr in terms of TiO ₂ or Cr ₂ O ₃ , and the atomic ratio of In is A (at%), and the atomic ratio of Ti or Cr is B (at%). When the atomic ratio of Zn or Sn is C (at%), 0.5 ≦ A / B ≦ 5, and 0 < C / (A + B) < 10. For example, the film of claim 8 is a refractive index of 2.05 at a wavelength of 550 nm. the above. The film of claim 8 or 9, wherein the extinction coefficient at a wavelength of 450 nm is 0.05 or less. The film of claim 8 or 9 has a specific resistance of 1 MΩcm or less. The film of claim 10, which has a specific resistance of 1 M?cm or less. A method for producing a sintered body, which is a method for producing a sintered body according to any one of claims 1 to 7, wherein the raw material powder is pressurized at 900 ° C or higher and 1500 ° C or lower in an inert gas or a vacuum atmosphere. After the sintering or the raw material powder is press-formed, 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.