TWI525060B - An oxide sintered body, a sputtering target, a thin film, and an oxide sintered body - Google Patents

Description

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

The present invention relates to an oxide sintered body, an oxide sputtering target, a thin film, and a method for producing an oxide sintered body, and more particularly to an oxide sputtering target capable of performing DC sputtering and a film having desired characteristics.

When various optical devices such as organic ELs, liquid crystal displays, and touch panels utilize visible light, the materials used must be transparent, and it is particularly desirable to have high transmittance in the entire region of the 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 between the substrates. There is such a method of introducing an optical adjustment layer (film) for high transmittance, reduction of light loss, and prevention of reflection.

In the past, in addition to the refractive index and the extinction coefficient (high transmittance), in addition to the refractive index and the extinction coefficient (high transmittance), the refractive index and the extinction coefficient (high transmittance) are mainly required for the optical adjustment layer. Coexistence of complex properties such as (etchable), water resistance, and amorphous film. In order to coexist such a complex characteristic, it is difficult to use a single oxide film, and a composite oxide film in which a plurality of oxides are mixed is required. In particular, a composite oxide film in which an oxide of a ternary system or more is mixed is effective.

In general, as a transparent and electrically conductive material, ITO (indium oxide-tin oxide), IZO (indium oxide-zinc oxide), GZO (gallium oxide-zinc oxide), AZO (aluminum oxide-zinc oxide) are known. ) (Patent Documents 1 to 3). However, these materials are absorbed in the short wavelength region, easily crystallized and not The law adequately controls the characteristics of the aforementioned complex numbers.

Patent Document 4 describes that the mobility of the film and the carrier density are increased by further adding other elements to IZO. Further, Patent Document 5 discloses that IGZO (indium oxide-gallium oxide-zinc oxide) containing a bixbyite structure and a spinel structure has low electrical resistivity and excellent film formation stability. However, either of them mainly attempts to improve the conductivity, rather than controlling the above complex characteristics at the same time.

Further, Patent Document 6 discloses a technique for producing dense AZO and GZO by a manufacturing method, and Patent Document 7 is completed by the inventors, and discloses that it is useful to obtain oxidation of a transparent conductive film having good transmittance and conductivity. Sintered body. However, in any of the techniques, it is difficult to adjust the characteristics of the plural at the same time.

In addition, the above-mentioned techniques are used as a transparent conductive film (electrode), and are different from the use of a film (optical adjustment film, protective film, etc.) which is disposed adjacent to the electrode for controlling optical characteristics and the like.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-008780

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-184876

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2007-238375

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2013-001919

[Patent Document 5] International Publication WO2011/040028

[Patent Document 6] International Publication WO2008/018402

[Patent Document 7] Japanese Patent No. 5550768

It is an object of the present invention to provide that it is possible to obtain desired optical and electrical properties. A sintered body of a conductive oxide film. The film has a high transmittance, a desired refractive index, and a good electrical conductivity, and is useful as a film for an optical device such as an organic EL, a liquid crystal display, or a touch panel, and particularly for an optical adjustment film. Further, an object of the present invention is to provide a sputtering target which has low bulk resistance and can be subjected to DC sputtering. The object of the present invention is to improve the characteristics of an optical device, reduce production costs, and greatly improve film formation properties.

In order to solve the above problems, the inventors of the present invention have diligently studied the results of obtaining a film having desired optical characteristics and electrical characteristics by using the following materials, and can be stabilized by DC sputtering. The film can improve the characteristics of the optical device using the film and improve productivity.

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

1) An oxide sintered body composed of zinc (Zn), indium (In), titanium (Ti), gallium (Ga), germanium (Ge), and oxygen (O), and has a Zn content of 70 in terms of ZnO. ~90 mol%, in terms of In ₂ O ₃ , the In content is 2 to 15 mol%, and the Ti content is 1 to 10 mol% in terms of TiO ₂ , and the Ga content is 0.5 to 10 mol% in terms of Ga ₂ O ₃ to GeO ₂ The conversion has a Ge content of 0.5 to 10 mol%.

(2) The oxide sintered body according to the above 1), which satisfies the following relationship: an In content of Ti is 2.0 ≦In/Ti≦4.0 in terms of atomic ratio, and an atomic ratio with respect to Ga content of Ge The ratio is 1.5 ≦ Ga / Ge ≦ 2.5, and the Zn content of In and Ti and Ga and Ge is 2.0 ≦ Zn / (In + Ti + Ga + Ge) ≦ 5.0 in terms of atomic ratio.

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

(4) The oxide sintered body according to any one of the above 1), wherein the volume resistivity is 10 Ω‧ cm or less.

5) A sputtering target using the oxide sintered body according to any one of the above 1) to 4).

6) A film comprising zinc (Zn), indium (In), titanium (Ti), gallium (Ga), germanium (Ge), and oxygen (O), in terms of ZnO, having a Zn content of 70 to 90 mol% In the case of In ₂ O ₃ , the In content is 2 to 15 mol%, and the Ti content is 1 to 10 mol% in terms of TiO ₂ , and the Ga content is 0.5 to 10 mol% in terms of Ga ₂ O ₃ , Ge in terms of GeO ₂ . The content is 0.5 to 10 mol%.

7) The film according to the above 6), which satisfies the following relationship: the In content relative to Ti is 2.0 Å in / Ti ≦ 4.0 in terms of atomic ratio, and the atomic ratio in terms of the Ga content of Ge is 1.5 ≦ Ga / Ge ≦ 2.5, with respect to the Zn content of In and Ti and Ga and Ge, is an atomic ratio of 2.0 ≦ Zn / (In + Ti + Ga + Ge) ≦ 5.0.

8) The film according to the above 6) or 7), which has a refractive index at a wavelength of 550 nm of 1.95 to 2.10.

9) The film according to any one of the above 6), wherein the extinction coefficient at a wavelength of 405 nm is 0.05 or less.

10) The film according to any one of the above 6) to 9), which has a volume resistivity of 1 kΩ·cm or less.

According to the present invention, by using the material system described above, the resistivity and the refractive index can be adjusted, and good optical characteristics and electrical conductivity can be ensured while ensuring good etching characteristics and water resistance. Further, the present invention can form a film stably by DC sputtering, thereby improving productivity.

The present invention is characterized in that it is composed of zinc (Zn), indium (In), titanium (Ti), gallium (Ga), germanium (Ge), and oxygen (O), and the Zn content is 70 to 90 mol% in terms of ZnO. In the case of In ₂ O ₃ , the In content is 2 to 15 mol%, and the Ti content is 1 to 10 mol% in terms of TiO ₂ , and the Ga content is 0.5 to 10 mol% in terms of Ga ₂ O ₃ , and Ge content in terms of GeO ₂ conversion. It is 0.5 to 10 mol%. By using the oxide sintered body sputtering target composed of such a composition, a conductive oxide thin film having desired optical characteristics (refractive index, transmittance) and electrical characteristics can be formed.

In the present invention, zinc (Zn), indium (In), titanium (Ti), gallium (Ga), germanium (Ge), and oxygen (O) are used as constituent elements, and the material also contains unavoidable impurities. Further, some or all of the metals in the sintered body exist in the form of a composite oxide. In the present invention, the content of each metal in the sintered body is defined in terms of oxide, but this is because the blending of the raw materials is adjusted with an oxide to explain the range and technical significance. Further, in a general analysis device, the content (% by weight) of each metal element can be specified instead of the oxide. Therefore, when it is desired to specify the respective compositions of the target, it can be specified by assuming that each oxide is then converted to the amount (mol%) of each metal element content.

In the present invention, the Zn content is 70 to 90 mol% in terms of ZnO. If it exceeds this range, it is not preferable because the desired optical characteristics and electrical characteristics are not obtained. In particular, when the Zn content is less than 70 mol% in terms of ZnO, the resistance of the film is increased to impair the performance as a conductive film, which is not preferable. On the other hand, when it exceeds 90 mol%, it is difficult to control the optical characteristics such as the refractive index, and the etching property and the water resistance are lowered, which is not preferable.

In the present invention, the content of In is 2 to 15 mol% in terms of In ₂ O ₃ . If it exceeds this range, it is not preferable because the desired optical characteristics and electrical characteristics are not obtained. In particular, when the In content is less than 2 mol%, the addition effect for the purpose of imparting conductivity (that is, it is preferable because it becomes high resistance) is not obtained, and on the other hand, if it exceeds 15 mol%, it is short in visible light. The light absorption in the wavelength region becomes large, so it is not good. Further, although In is a trivalent metal element, if it is substituted with another metal of the same price (for example, Al or B), the electric resistance is increased and the water resistance is lowered, which is not preferable.

In the present invention, the Ti content is set to 1 to 10 mol% in terms of TiO ₂ . If it exceeds this range, it is not preferable because the desired optical characteristics and electrical characteristics are not obtained. In particular, if the Ti content is less than 1 mol%, the effect of addition for the purpose of optical adjustment cannot be obtained. On the other hand, when it exceeds 10 mol%, since the electric resistance of a film becomes high and the performance as a conductive film is impaired, it is unpreferable. Further, Ti oxide is known as a high refractive index material, but it is not preferable because it is substituted with another metal having the same effect (for example, Bi, Fe, Co, or the like), which is absorbed in a short-wavelength region of visible light.

In the present invention, the Ga content is set to 0.5 to 10 mol% in terms of Ga ₂ O ₃ . If it exceeds this range, it is not preferable because the desired optical characteristics and electrical characteristics are not obtained. In particular, when the Ga content is less than 0.5 mol%, the effect of adding optical properties and imparting conductivity is not obtained. On the other hand, when it exceeds 10 mol%, the electric resistance of the sintered body and the film becomes high, which is not preferable. Further, although Ga is a trivalent element, substitution with other metals of the same valence (for example, Al or B) causes an increase in electric resistance and a decrease in water resistance, which is not preferable.

In the present invention, the Ge content is set to 0.5 to 10 mol% in terms of GeO ₂ . If it exceeds this range, it is not preferable because the desired optical characteristics and electrical characteristics are not obtained. In particular, when the Ge content is less than 0.5 mol%, the effect of addition for the purpose of optical adjustment cannot be obtained. On the other hand, when it exceeds 10 mol%, the electric resistance of the sintered body and the film becomes high, which is not preferable. Further, Ge is a metal having a low refractive index and constituting a glass forming oxide. However, it is not preferable because it is replaced with another metal (for example, Si or B) constituting the glass forming oxide, which causes an increase in electric resistance and a decrease in water resistance.

In the present invention, it is preferable to satisfy the following relationship: the In content with respect to Ti is 2.0 Å in / Ti ≦ 4.0 in terms of atomic ratio, and the Ga content relative to Ge is 1.5 ≦ Ga in atomic ratio. /Ge≦2.5. If it exceeds this range, it is difficult to combine the desired optical characteristics and electrical characteristics. Further, it is preferable to satisfy the following relational expression: a relationship of 2.0 ≦ Zn / (In + Ti + Ga + Ge) ≦ 5.0 with respect to the Zn content of In and Ti and Ga and Ge in terms of atomic ratio. If it exceeds this range, It is difficult to achieve both desired optical characteristics and electrical characteristics, and if it exceeds 5.0, the addition effect of In, Ti, Ga, and Ge may not be obtained, and water resistance and etching property may be impaired. Further, if it is less than 2.0, the desired conductivity may not be obtained, and the function as a conductive film may be impaired.

When the sintered body of the present invention is used as a sputtering target, the relative density is preferably set to 90% or more. The density is increased to improve the uniformity of the sputter film and to suppress the generation of particles during sputtering. The relative density of 90% or more can be achieved by the following method for producing a sintered body of the present invention.

Further, when the sintered body of the present invention is used as a sputtering target, the volume resistivity is preferably 10 Ω‧ cm or less. Film formation can be performed by DC sputtering by lowering the volume resistivity. Compared to RF sputterling, DC sputtering provides faster film formation and better sputtering efficiency, which increases throughput. Furthermore, depending on the manufacturing conditions, although there is also a case of performing RF sputtering, the film formation speed is also improved in this case.

In general, in order to prevent reflection and reduce light loss, a material having a specific refractive index is required, but the necessary refractive index differs depending on the device configuration (the refractive index of the peripheral layer of the optical adjustment film). In the present invention, the refractive index n of the film at a wavelength of 550 nm can be controlled within the range of 1.95 ≦ n ≦ 2.10. Further, the optical adjustment film itself preferably has a high refractive index (small extinction coefficient). In the present invention, when the extinction coefficient at a wavelength of 405 nm is 0.05 or less, a film which is hardly absorbed in a short-wavelength region of visible light can be obtained. Further, in order to assist the adjacent electrode layers, the optical adjustment layer requires an appropriate conductivity. In the present invention, the volume resistivity of the film can be controlled to 1 kΩ·cm or less. Further, the film of the present invention is characterized by having excellent etching characteristics and excellent high temperature and high humidity resistance.

The sintered body of the present invention can be produced by weighing and mixing a raw material powder composed of oxide powders of respective constituent metals, and then subjecting the mixed powder to hot press in an inert gas atmosphere or a vacuum atmosphere. After the raw material powder is press-formed, the formed body is subjected to normal pressure sintering. At this time, the sintering temperature is preferably 900 ° C or more and 1500 ° C or less. If it is less than 900 ° C, a high-density sintered body cannot be obtained. On the other hand, if it exceeds 1500 ° C, the composition deviation and the decrease in density due to evaporation of the material may occur, which is not preferable. Further, the pressurizing pressure is preferably from 150 to 500 kgf/cm ² .

Further, in order to increase the density, the mixed powder is subjected to calcination (synthesis) after weighing and mixing the raw material powder, and thereafter, it is effective to use the finely pulverized material as a powder for sintering. By performing the synthesis and fine pulverization in advance 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 has an average particle diameter of 5 μm or less, and preferably has an average particle diameter of 2 μm or less. Further, the calcination temperature is preferably set to 800 ° C or more and 1200 ° C or less. By setting it as such a range, sinterability becomes favorable, and it can further increase density.

[Examples]

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 invention.

The evaluation methods of the examples and comparative examples are as follows.

(about composition)

Device: SPS3500DD manufactured by SII

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

(about density measurement)

Dimensional measurement (caliper), weight measurement

(about relative density)

The following calculation is performed using the theoretical density.

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

The theoretical density is calculated based on the oxide ratio conversion ratio of each metal element.

The ZnO conversion weight of Zn is set to a% (wt%), the In ₂ O ₃ equivalent weight of In is set to b% (wt%), and the Ti TiO ₂ conversion weight is set to c% (wt%). The Ga ₂ O ₃ converted weight of Ga is set to d% (wt%), and when the GeO ₂ converted weight of Ge is set to e% (wt%), the theoretical density = 100 / (a/5.61 + b / 7.18 + c / 4.26+d/5.95+e/4.70)

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

ZnO: 5.61 g/cm ³ , In ₂ O ₃ : 7.18 g/cm ³

TiO ₂ : 4.26 g/cm ³ , Ga ₂ O ₃ : 5.95 g/cm ³

GeO ₂ : 4.70g/cm ³

(About body resistivity, volume resistivity)

Device: Resistivity meter manufactured by NPS Σ-5+

Method: DC four-probe method

(About film formation method and conditions)

Device: ANELVA SPL-500

target: 6inch×5mmt

Substrate: 4inch

Substrate temperature: room temperature

(about refractive index, extinction coefficient)

Device: Spectrophotometer UV-2450 manufactured by SHIMADZU

Method: Calculated by transmittance, reflectance of inside and outside

(Example 1)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1, and mixed. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore size of 150 μm. Thereafter, the finely pulverized powder was subjected to hot press sintering under the conditions of a temperature of 1,100 ° C and a pressure of 250 kgf / cm ² in a vacuum. Thereafter, the sintered body is machined into a sputtering target shape by machining. As a result of measuring the volume resistivity and the relative density of the obtained target, as shown in Table 1, the relative density was 98.4%, and the volume resistivity was 0.04 Ω ‧ cm, and stable DC sputtering was possible. Further, the results of analyzing the composition of the sputtering target were confirmed to be the same as the blending ratio with the raw material powder.

Sputtering is performed using the above-described finished target. The sputtering conditions were DC sputtering, sputtering power of 500 W, and Ar gas pressure of 0.8 vol% of oxygen was set to 0.5 Pa, and film formation was performed to a film thickness of 5000 to 7000 Å. The refractive index (wavelength 550 nm), extinction coefficient (405 nm), and volume resistivity of the film-forming sample were measured. As shown in Table 1, the refractive index of the film formed by sputtering was 1.97, the extinction coefficient was less than 0.01, and the volume resistivity was 1 × 10 ³ Ω ‧ cm or less, and desired optical characteristics and conductivity were obtained.

(Example 2)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1, and mixed. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ particles) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore diameter of 150 μm. Thereafter, this finely pulverized powder was subjected to hot press sintering in the same manner as in Example 1. Thereafter, the sintered body is machined to be finished into a sputtering target shape. As a result of measuring the volume resistivity and relative density of the target obtained, as shown in Table 1, the relative density was 98.0%, and the volume resistivity was 0.03 Ω ‧ cm, and stable DC sputtering was possible.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Example 1. The measurement results of the refractive index (wavelength 550 nm), extinction coefficient (wavelength 405 nm), and volume resistivity of the film-forming sample are shown in Table 1. If the film formed by sputtering has a refractive index of 2.05, an extinction coefficient of 0.03, and a volume. When the specific resistance is 1 × 10 ³ Ω ‧ cm or less, desired optical characteristics and conductivity can be obtained.

(Example 3)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1, and mixed. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ particles) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore diameter of 150 μm. Thereafter, this finely pulverized powder was subjected to hot press sintering in the same manner as in Example 1. Thereafter, the sintered body is machined to be finished into a sputtering target shape. The results of measuring the volume resistivity and the relative density of the obtained target are shown in Table 1. The relative density was 98.0%, and the volume resistivity was 0.03 Ω ‧ cm, and stable DC sputtering was possible.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Example 1. The measurement results of the refractive index (wavelength 550 nm), extinction coefficient (wavelength 405 nm), and volume resistivity of the film-forming sample are shown in Table 1. If the film formed by sputtering has a refractive index of 2.05, an extinction coefficient of 0.03, and a volume. When the specific resistance is 1 × 10 ³ Ω ‧ cm or less, desired optical characteristics and conductivity can be obtained.

(Example 4)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1 and mixed. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ particles) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore diameter of 150 μm. Thereafter, this finely pulverized powder was subjected to hot press sintering in the same manner as in Example 1. Thereafter, the sintered body is machined to be finished into a sputtering target shape. The results of measuring the volume resistivity and the relative density of the target obtained are shown in Table 1. The relative density was 98.5%, and the volume resistivity was 0.01 Ω ‧ cm, which was stable DC sputtering.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Example 1. The measurement results of the refractive index (wavelength 550 nm), extinction coefficient (wavelength 405 nm), and volume resistivity of the film-forming sample are shown in Table 1. If the film formed by sputtering has a refractive index of 2.04, an extinction coefficient of 0.04, and a volume. When the specific resistance is 1 × 10 ³ Ω ‧ cm or less, desired optical characteristics and conductivity can be obtained.

(Example 5)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1 and mixed. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ particles) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore diameter of 150 μm. Thereafter, this finely pulverized powder was subjected to hot press sintering in the same manner as in Example 1. Thereafter, the sintered body is machined to be finished into a sputtering target shape. The results of measuring the volume resistivity and the relative density of the obtained target are shown in Table 1. The relative density was 98.4%, and the volume resistivity was 0.01 Ω ‧ cm, which was stable DC sputtering.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Example 1. The measurement results of the refractive index (wavelength 550 nm), extinction coefficient (wavelength 405 nm), and volume resistivity of the film-forming sample are shown in Table 1. If the film formed by sputtering has a refractive index of 1.99, an extinction coefficient of 0.01, and a volume. When the specific resistance is 1 × 10 ³ Ω ‧ cm or less, desired optical characteristics and conductivity can be obtained.

(Example 6)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1 and mixed. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ particles) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore size of 150 μm. Thereafter, this finely pulverized powder was subjected to hot press sintering in the same manner as in Example 1. Thereafter, the sintered body is machined to be finished into a sputtering target shape. The results of measuring the volume resistivity and the relative density of the target obtained are shown in Table 1. The relative density was 97.7%, and the volume resistivity was 0.06 Ω ‧ cm, enabling stable DC sputtering.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Example 1. The measurement results of the refractive index (wavelength 550 nm), extinction coefficient (wavelength 405 nm), and volume resistivity of the film-forming sample are shown in Table 1. If the film formed by sputtering has a refractive index of 1.96, an extinction coefficient of 0.01, and a volume. When the specific resistance is 1 × 10 ³ Ω ‧ cm or less, desired optical characteristics and conductivity can be obtained.

(Example 7)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1 and mixed. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ particles) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore diameter of 150 μm. Thereafter, this finely pulverized powder was subjected to hot press sintering in the same manner as in Example 1. Thereafter, the sintered body is machined to be finished into a sputtering target shape. The results of measuring the volume resistivity and relative density of the target obtained are shown in Table 1. The relative density was 99.2%, and the volume resistivity was 0.01 Ω ‧ cm, which was stable DC sputtering.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Example 1. The refractive index (wavelength 550 nm), extinction coefficient (wavelength 405 nm), and volume resistivity of the film-forming sample are shown in Table 1. If the film formed by sputtering has a refractive index of 2.02 and an extinction coefficient of 0.02, the volume is 0.02. When the specific resistance is 1 × 10 ³ Ω ‧ cm or less, desired optical characteristics and conductivity can be obtained.

(Comparative Example 1)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1, and mixed. At this time, the amount of In ₂ O ₃ is made larger than the predetermined amount, and the amount of ZnO is smaller than the predetermined amount. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore size of 150 μm. Thereafter, the finely pulverized powder was subjected to hot press sintering under the same conditions as in Example 1. Thereafter, the sintered body is finished by machining into a sputtering target shape.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Example 1. As a result of measuring the extinction coefficient (wavelength 405 nm) of the film-forming sample, as shown in Table 1, the extinction coefficient of the film formed by sputtering exceeded 0.05, and light absorption occurred in the low-wavelength region, and the desired transmittance could not be obtained. .

(Comparative Example 2)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1, and mixed. At this time, the amount of TiO ₂ is made larger than a predetermined amount, and the amount of ZnO is smaller than a predetermined amount. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore size of 150 μm. Thereafter, the finely pulverized powder was subjected to hot press sintering under the same conditions as in Example 1. Thereafter, the sintered body is finished by machining into a sputtering target shape. As a result of measuring the volume resistivity of the target obtained, etc., as shown in Table 1, the volume resistivity was 15 Ω ‧ cm, and it was difficult to perform stable DC sputtering.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Example 1. As a result of measuring the volume resistivity of the film-forming sample, etc., as shown in Table 1, the volume resistivity of the film formed by sputtering was 1 × 10 ³ Ω ‧ cm or more, and the desired conductivity could not be obtained.

(Comparative Example 3)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1, and mixed. At this time, the amount of Ga ₂ O ₃ is made larger than the predetermined amount, and the amount of ZnO is made smaller than the predetermined amount. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore size of 150 μm. Thereafter, the finely pulverized powder was subjected to hot press sintering under the same conditions as in Example 1. Thereafter, the sintered body is finished by machining into a sputtering target shape. As a result of measuring the volume resistivity of the target obtained, etc., as shown in Table 1, the volume resistivity was 500 kΩ·cm or more, and it was difficult to perform stable DC sputtering.

Then, the finished target is used for sputtering. The sputtering conditions were RF sputtering, sputtering power of 500 W, and Ar gas pressure of 0.8 vol% containing oxygen atoms was set to 0.5 Pa, and film formation was performed to a film thickness of 5000 to 7000 Å. As a result of measuring the volume resistivity and the like of the film-forming sample, as shown in Table 1, the volume resistivity of the film formed by sputtering was 1 × 10 ³ Ω ‧ cm or more, and the desired conductivity could not be obtained.

(Comparative Example 4)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1, and mixed. At this time, the amount of GeO ₂ is made larger than the predetermined amount, and the amount of ZnO is smaller than the predetermined amount. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore size of 150 μm. Thereafter, the finely pulverized powder was subjected to hot press sintering under the same conditions as in Example 1. Thereafter, the sintered body is finished by machining into a sputtering target shape. As a result of measuring the volume resistivity of the target obtained, etc., as shown in Table 1, the volume resistivity was 500 kΩ·cm or more, and it was difficult to perform stable DC sputtering.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Comparative Example 3. As a result of measuring the volume resistivity and the like of the film-forming sample, as shown in Table 1, the volume resistivity of the film formed by sputtering was 1 × 10 ³ Ω ‧ cm or more, and the desired conductivity could not be obtained.

(Comparative Example 5)

ZnO powder, In ₂ O ₃ powder, TiO ₂ powder, Ga ₂ O ₃ powder, and GeO ₂ powder were prepared, and the powders were blended into the blend ratios shown in Table 1, and mixed. At this time, the amount of ZnO is made larger than a predetermined amount, and the amounts of In ₂ O ₃ , TiO ₂ , Ga ₂ O ₃ , and GeO ₂ are smaller than a predetermined amount. Subsequently, the mixed powder was calcined at a temperature of 1050 ° C in the air, and then pulverized by wet fine pulverization (using ZrO ₂ beads) to an average particle diameter of 2 μm or less, dried, and sieved with a sieve having a pore size of 150 μm. Thereafter, the finely pulverized powder was subjected to hot press sintering under the same conditions as in Example 1. Thereafter, the sintered body is finished by machining into a sputtering target shape.

Then, the finished target is used for sputtering. The sputtering conditions were the same as in Example 1. The measurement results of the refractive index (wavelength 550 nm), extinction coefficient (wavelength 405 nm), and volume resistivity of the film-forming sample are as shown in Table 1, and desired optical characteristics and conductivity can be obtained. Thereafter, this film-forming sample is subjected to Etching resistance test (determined by etching with various acids, ○ can not be etched or over-dissolved), and high-temperature and high-humidity test (keeping at a temperature of 80 ° C and a humidity of 80%) After 48 hours, the optical constant and the electric resistance measurement were carried out so that the difference in the characteristics before and after the high-temperature and high-humidity test was less than 10%, and the result was judged by the fact that the difference was less than 10%, and the ZnO was more in the composition. In the case, the etching characteristics are poor (over-dissolving), and the high-temperature and high-humidity characteristics are poor, and a film having desired characteristics cannot be obtained.

The sintered body of the present invention can be used as a sputtering target and a film formed by using a sputtering target, and has the following effects: a transparent conductive film for various display devices, a protective film for a optical disk, and a film for optical adjustment, in transmittance and refractive index. Excellent in electrical conductivity.

Further, since the sputtering target of the present invention has a low bulk resistivity and a high density of 90% or more, stable DC sputtering can be performed. Moreover, it has the remarkable effect that the sputtering control property for the characteristics of the DC sputtering can be made easy, the film formation speed can be improved, and the sputtering efficiency can be improved. RF sputtering is performed as necessary, but in this case, an increase in film formation speed can be observed. Further, it is possible to reduce particles (dust) or nodule which occur at the time of sputtering at the time of film formation, and the quality is inconsistent, and the mass productivity can be improved.

Claims (13)

An oxide sintered body composed of zinc (Zn), indium (In), titanium (Ti), gallium (Ga), germanium (Ge), and oxygen (O), and has a Zn content of 70 to 90 mol in terms of ZnO. %, in terms of In ₂ O ₃ , the In content is 2 to 15 mol%, and the Ti content is 1 to 10 mol% in terms of TiO ₂ , and the Ga content is 0.5 to 10 mol% in terms of Ga ₂ O ₃ , in terms of GeO ₂ conversion. The Ge content is 0.5 to 10 mol%. The oxide sintered body according to claim 1, which satisfies the following relationship: the In content with respect to Ti is 2.0 ≦In/Ti ≦ 4.0 in terms of atomic ratio, and the atomic ratio with respect to the Ga content of Ge is 1.5 ≦ Ga / Ge ≦ 2.5 is 2.0 ≦ Zn / (In + Ti + Ga + Ge) ≦ 5.0 with respect to the Zn content of In and Ti and Ga and Ge in atomic ratio. The oxide sintered body according to claim 1 has a relative density of 90% or more. The oxide sintered body according to Patent Application No. 2 has a relative density of 90% or more. The oxide sintered body according to any one of claims 1 to 4, which has a volume resistivity of 10 Ω ‧ or less. A sputtering target using the oxide sintered body according to any one of claims 1 to 5. A thin film composed of zinc (Zn), indium (In), titanium (Ti), gallium (Ga), germanium (Ge), and oxygen (O), and has a Zn content of 70 to 90 mol% in terms of ZnO. In ₂ O ₃ conversion, the In content is 2 to 15 mol%, and the Ti content is 1 to 10 mol% in terms of TiO ₂ , and the Ga content is 0.5 to 10 mol% in terms of Ga ₂ O ₃ , and the Ge content is in terms of GeO ₂ conversion. 0.5 to 10 mol%. The film according to claim 7, which satisfies the following relationship: the In content relative to Ti is 2.0 ≦In/Ti≦4.0 in terms of atomic ratio, and the Ga content in Ge is 1.5 in atomic ratio. ≦Ga/Ge≦2.5 is 2.0≦Zn/(In+Ti+Ga+Ge)≦5.0 with respect to the Zn content of In and Ti and Ga and Ge in atomic ratio. The film of the invention of claim 7 has a refractive index of 1.95 to 2.10 at a wavelength of 550 nm. The film of the invention of claim 8 has a refractive index of 1.95 to 2.10 at a wavelength of 550 nm. The film according to any one of claims 7 to 10, wherein the extinction coefficient at a wavelength of 405 nm is 0.05 or less. The film according to any one of claims 7 to 10, which has a volume resistivity of 1 kΩ·cm or less. The film according to any one of claims 11 is having a volume resistivity of 1 kΩ·cm or less.