Sintered body, sputtering target, and method for producing sintered body

Abstract

The present disclosure addresses the problem of providing: a sintered body and a sputtering target that contain indium, zinc, and oxygen and have high hardness; and a method for producing a sintered body. Provided is an IZO sintered body containing indium, zinc, and oxygen, wherein: the sintered body contains an In2O3 phase and a Zn5In2O8 phase; and I1 / I2 is 0.5 or greater, where I1 is the X-ray diffraction peak intensity at 34.1° ≤ 2θ ≤ 35.1° of the Zn5In2O8 phase, and I2 is the sum of X-ray diffraction peak intensities at 34.1° ≤ 2θ ≤ 35.1° of a Zn3In2 O6 phase and a Zn4In2O7 phase.

Description

Sintered body, sputtering target, and method for producing sintered body

[0001] The present disclosure relates to a sintered body, a sputtering target, and a method for producing a sintered body.

[0002] Thin films of oxides whose main component is indium oxide, such as indium oxide-tin oxide (referred to as "ITO") and indium oxide-zinc oxide (referred to as "IZO"), have high conductivity and transparency in the visible light region, and are therefore used as electrode materials for various flat panel displays. IZO in particular has properties such as low resistance and high transmittance when formed at room temperature, the formation of stable amorphous films, good etching properties, and high film flatness. IZO also has properties as an oxide semiconductor, and its use as a channel layer for TFTs, etc., is also being considered.

[0003] As a method for forming an IZO film, a sputtering method using an IZO sputtering target manufactured from an IZO sintered body is widely used. ２ O ３ and Zn ｋ In ２ O ｋ＋３ (k=one or more of 3, 4, and 5), the target has a relative density of 98.4% or more, the number of micropores of 50 to 300 nm present in the target is 10 or less, and the atomic ratio of Zn to In, Zn / (In+Zn), is in the range of 0.1 to 0.2.

[0004] Patent No. 6078189

[0005] In an IZO sputtering target containing indium, zinc, and oxygen, a problem of cracks and fractures occurring in the sputtering target has arisen. In view of the above problem, an object of the present disclosure is to provide a sintered body and sputtering target containing indium, zinc, and oxygen and having high hardness, as well as a method for manufacturing the sintered body.

[0006] The gist of the present disclosure is as follows: [1] An IZO sintered body containing indium, zinc, and oxygen, comprising In ２ O ３ phase and Zn ５ In ２ O ８ phase, Zn ５ In ２ O ８ The X-ray diffraction peak intensity of the Zn phase at 34.1°≦2θ≦35.1° is designated as I1. ３ In ２ O ６ phase and Zn ４ In ２ O ７ A sintered body having an I1 / I2 ratio of 0.5 or more, where I2 is the sum of X-ray diffraction peak intensities of the phase at 34.1°≦2θ≦35.1°. [2] A sintered body according to [1], having a relative density of 90% or more. [3] A sintered body according to [1] or [2], having a volume resistivity of 10 mΩ cm or less. [4] A sintered body according to any one of [1] to [3], having a Zn content of 1 mass % or more and 37 mass % or less, calculated as ZnO. [5] A sintered body according to any one of [1] to [4], having an average crystal grain size of 5 μm or less. [6] A sputtering target produced from the sintered body according to any one of [1] to [5]. [7] In ２ O ３ The resulting mixed powder was heated in a vacuum or inert gas atmosphere at 1000°C or higher but lower than 1200°C under a pressure of 150 kgf / cm. ２ [8] The method for producing a sintered body according to [7], wherein the mixed powder is calcined at a temperature of 1000°C or higher but lower than 1200°C, and the calcined powder is calcined under pressure.

[0007] According to the present disclosure, it is possible to provide a sintered body and a sputtering target containing indium, zinc, and oxygen and having high hardness, as well as a method for producing the sintered body.

[0008] 1 shows an X-ray diffraction pattern (10°≦2θ≦80°) of the sintered body of Example 4. FIG. 2 shows an X-ray diffraction pattern (34.1°≦2θ≦35.1°) of the sintered body of Example 4.

[0009] Below, the present disclosure will be described with reference to specific embodiments, but each configuration and their combinations in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of configurations are possible as appropriate within the scope that does not deviate from the gist of the present disclosure.

[0010] A sintered body according to an embodiment of the present disclosure (hereinafter referred to as the present embodiment) contains indium, zinc, and oxygen. A sintered body having such a composition is called an IZO sintered body. IZO is an abbreviation derived from the initials of the constituent elements indium (In), zinc (Zn), and oxygen (O). IZO thin films can be used as transparent conductive films or oxide semiconductors.

[0011] An IZO thin film can usually be formed by sputtering. A sputtering target made from an IZO sintered body (referred to as an IZO sputtering target) is placed in a vacuum chamber, and argon ions generated by glow discharge are made to collide with the sputtering target at high speed, causing the ejected atoms to be deposited on an opposing glass substrate or the like, thereby forming a thin film with approximately the same composition as the sputtering target.

[0012] The sintered body according to this embodiment is made of In ２ O ３ phase and Zn ５ In ２ O ８ phase, Zn ５ In ２ O ８ The X-ray diffraction peak intensity of the Zn phase at 34.1°≦2θ≦35.1° is designated as I1. ３ In ２ O ６ phase and Zn ４ In ２ O ７ When the sum of the X-ray diffraction peak intensities of the indium and zinc composite oxide phase at 34.1°≦2θ≦35.1° is I2, I1 / I2 is 0.5 or more. ５ In ２ O ８ It can be determined that the indium-zinc composite oxide contains Zn.５ In ２ O ８ In addition to the phase, Zn ３ In ２ O ６ Phase, Zn ４ In ２ O ７ Among these complex oxide phases, Zn ５ In ２ O ８ By controlling the crystal phase so that the phase becomes the main phase, the hardness of the IZO sputtering target can be improved. A sputtering target with high hardness can suppress particle generation during sputtering.

[0013] The sintered body according to this embodiment preferably has a relative density of 90% or more. High density sputtering targets made from IZO sintered bodies can contribute to improving the hardness of the sintered body. This can suppress particle generation during sputtering. Since IZO sintered bodies require a fine crystal structure, they are preferably sintered at low temperatures, which can suppress grain growth. However, it is difficult to obtain high-density sintered bodies with low-temperature sintering. However, according to the manufacturing method of the present disclosure, which will be described in detail later, it is possible to obtain high-density sintered bodies while suppressing grain growth. A more preferred relative density is 95% or more, and an especially preferred relative density is 97% or more.

[0014] The sintered body according to this embodiment preferably has a volume resistivity of 10 mΩ·cm or less. If the volume resistivity is high, arcing occurs during sputtering, which can cause particles, so it is preferable that the volume resistivity be as low as possible. If oxygen deficiency occurs in the sintered body, the volume resistivity decreases, so the sintering conditions are adjusted to generate oxygen deficiency. The volume resistivity is preferably 6 mΩ·cm or less, and more preferably 3 mΩ·cm or less.

[0015] The sintered body according to this embodiment contains indium (In), zinc (Zn), and oxygen (O), and the content of each element is not particularly limited. However, since the Zn content affects the conductivity of the target film, it is preferably 1% by mass or more and 37% by mass or less, calculated as ZnO. The lower limit of the Zn content is more preferably 2.5% by mass or more, calculated as ZnO, and particularly preferably 7.0% by mass or more. The upper limit of the Zn content is preferably 25% by mass or less, calculated as ZnO, and particularly preferably 15% by mass or less.

[0016] The sintered body according to this embodiment preferably has an average crystal grain size of 2 μm or less. It is more preferably 1.5 μm or less, and even more preferably 1 μm or less. If the average crystal grain size of the sintered body is coarse, the flexural strength decreases, and cracks and fractures may occur during sputtering. Cracks and fractures cause the generation of particles and nodules during sputtering. Therefore, to prevent cracks and fractures, it is preferable to refine the structure of the IZO sintered body (IZO sputtering target). The crystal grain size depends on the particle size of the powder used as the sintering raw material and various sintering conditions, and therefore these must be appropriately controlled.

[0017] The sintered body of this embodiment can be used as a PVD (physical vapor deposition) material, and can be used, for example, as a sputtering target, a vacuum deposition material, an ion plating material, etc. When used as a sputtering target, it can be formed into a disk-shaped plate, a rectangular plate, or a cylindrical shape, and can be bonded to a backing plate with a bonding material. When used as a sputtering target, its thickness can be 20 mm or less, preferably 3.0 to 15 mm, and more preferably 3.0 to 12 mm. The area of ​​the sputtered surface (sputtering surface) is 44 cm ２ It is preferable that the diameter is 75 mm or more.

[0018] A method for manufacturing a sintered body and a sputtering target according to this embodiment will now be described. However, the manufacturing conditions and the like below are not limited to the disclosed range, and it is clear that some omissions and modifications may be made. In addition, detailed descriptions of well-known manufacturing steps and processing operations will be omitted to avoid unnecessarily obscuring the disclosed manufacturing method.

[0019] (1. Raw Material Powder) As the raw material powder, indium oxide (In ２ O ３ ) powder and zinc oxide (ZnO) powder are prepared. ２ O ３ The powder has a median diameter d ５０ :0.5-3.0μm, specific surface area: 4.0-10m ２ The ZnO powder preferably has a median diameter d ５０ The particle size is preferably 0.1 to 2.0 μm. The raw material powder preferably has a purity of 99.9% by mass or more.

[0020] (2. Mixing Step) The raw material powders are weighed to have the desired composition ratio (content ratio of the sintered body), and then mixed. It is preferable to mix as uniformly as possible, and either wet mixing or dry mixing may be used. If the mixing is uneven, the sintered body may not have the desired crystal phase in the calcination step described later. Therefore, the mixing step is carried out while thoroughly checking that the raw material powders are mixed uniformly.

[0021] (3. Sieving step: optional) When wet mixing is performed, the slurry may be dried and further sieved using a sieve to break up agglomerations during drying. If the mesh size of the sieve is 500 μm or less, it is possible to break up agglomerations. The smaller the mesh size, the more agglomerations can be broken up, and by setting the mesh size to 250 μm or less, or even 150 μm or less, it is possible to break up agglomerations even more. On the other hand, if the mesh size is too small, the work may become complicated.

[0022] (4. Calcination Step: Optional) Next, the mixed powder can be calcined at 1000° C. or higher and lower than 1200° C. By performing the calcination, Zn can be removed before sintering. ５ In ２ O ８If the calcination temperature is 1200°C or higher, the sintered body will have the desired crystalline phase, Zn. ５ In ２ O ８ phase, but Zn ４ In ２ O ７ If the calcination temperature is too high, the sintering will be too hard, which may make the crushing process in the subsequent step complicated. ５ In ２ O ８ The calcination time is preferably 1 to 10 hours. If the calcination time is too short, the desired crystalline phase will not be formed, whereas if the calcination time is too long, the calcination will be too hard, which may complicate the subsequent crushing process. There are no particular restrictions on the rate of temperature increase or decrease. For example, the temperature can be increased to the desired temperature at a rate of 1°C / min to 10°C / min, and after the temperature has been maintained, the temperature can be decreased by furnace cooling. The calcination step may be omitted, in which case it is preferable to carry out the crushing step described below after weighing.

[0023] (5. Crushing step: optional) The calcined powder obtained by the above calcination is preferably crushed using a sieve. If the mesh size of the sieve is 500 μm or less, the densification can be removed. The smaller the mesh size, the more the densification can be removed, and by setting the mesh size to 250 μm or even 150 μm, the densification can be further removed. On the other hand, if the mesh size is too large, the crushing operation in the next step may become complicated.

[0024] (6. Pulverization step: optional) Next, pulverization can be carried out as necessary. There are various pulverization methods depending on the desired particle size and the material to be pulverized, and wet or dry ball mills, vibration mills, bead mills, etc. can be used. In order to obtain uniform and fine crystal particles, a wet bead mill mixing method is preferred, which has high efficiency in crushing agglomerates in a short time and also provides a good dispersion state of additives. The median diameter d after pulverization ５０ is preferably 0.1 to 1.0 μm.

[0025] (7. Sintering Step) Next, sintering is performed. Conventionally, sintering has been performed in air or an oxygen gas atmosphere at approximately 1400°C to 1600°C (so-called atmospheric sintering, atmospheric sintering). However, as the sintering temperature increases, grain growth occurs, resulting in a decrease in hardness. In addition, the volume resistivity increases, and particles are generated during sputtering, making stable sputtering difficult. In particular, as sputtering targets become larger and uniform film deposition is attempted using high-power sputtering, stabilizing sputtering is important.

[0026] (7-1. Sintering Method) In the manufacturing method of the present disclosure, pressure sintering is performed from the viewpoint of increasing the relative density at a relatively low temperature. For pressure sintering, hot press (HP) sintering or SPS (spark plasma sintering) can be used. The atmosphere during sintering is preferably an inert gas atmosphere rather than a vacuum. Furthermore, when sintering is performed in an inert gas atmosphere without pressure (atmospheric pressure), In ２ O ３ However, this may reduce the Zn content, hindering the increase in density of the sintered body and contaminating the inside of the device. Therefore, pressure sintering is preferred from the viewpoint of being able to suppress reduction to some extent, and hot press sintering is particularly preferred from the viewpoint of productivity. The sintering temperature is preferably 1000°C or higher and lower than 1200°C. If the sintering temperature is lower than 1000°C, the density of the sintered body will not increase sufficiently, while if the sintering temperature is 1200°C or higher, the Zn content will not increase, which is the desired crystal phase of the sintered body. ５ In ２ O ８ phase, but Zn ４ In ２ O ７ Phases emerge.

[0027] (7-2. Pressing pressure) The pressing pressure during pressure sintering is 150 kgf / cm ２ It is preferable that the pressing pressure is 150 kgf / cm or more. ２ If the pressure is less than this, the density of the sintered body may decrease. Although there is no particular upper limit, it is set to 400 kgf / cm2 in view of the strength of the members used in pressure sintering. ２ It is preferable to have the following:

[0028] (7-3. Sintering Holding Time) The holding time at the maximum sintering temperature is preferably 3 hours or more and 10 hours or less. A shorter holding time is preferable because it increases productivity, but if the holding time is too short, it becomes difficult to obtain a high-density sintered body. As described above, the manufacturing method of the present disclosure enables sintering at a relatively high temperature, and therefore the holding time can be shortened accordingly, making it possible to significantly improve productivity.

[0029] (7-4. HIP Treatment: Optional) After pressure sintering, the obtained sintered body may be subjected to HIP (hot isostatic pressing). The HIP treatment is preferably carried out at a temperature of 900°C or higher and lower than 1200°C. The pressure is preferably 1000 kgf / cm. ２ More than 1800kgf / cm ２ The treatment time is preferably 1 hour or more and 10 hours or less.

[0030] (8. Finishing) The sintered body obtained through the above sintering step can be processed into a desired shape using a processing machine such as a surface grinder, a cylindrical grinder, or a machining machine, and the surface can be polished to form a sputtering target. There are no particular restrictions on the shape of the sputtering target, and it can be a flat disk, a rectangle, a cylinder, or the like. Furthermore, the sputtering target can be bonded to a backing plate for use, if necessary.

[0031] The following description will be given based on examples and comparative examples. Note that these examples are merely examples and are not intended to limit the scope of the present invention. That is, the present invention is limited only by the scope of the claims, and includes various modifications other than the examples included in this disclosure.

[0032] The evaluation methods used in the examples and comparative examples are as follows. Sputtering targets are produced by subjecting sintered bodies to processing such as grinding and polishing, and therefore the properties of the sintered bodies can be considered equivalent to the properties of sputtering targets. Furthermore, in this disclosure, various evaluations are performed on samples representative of sintered bodies, and if the various physical properties of the representative samples fall within the scope of this disclosure, the sintered bodies are encompassed by the present invention. In other words, measuring a unique, exceptional, or partial sample that is not representative of a sintered body does not mean that the sample falls outside the scope of this disclosure.

[0033] (Composition Analysis) The composition of the sintered body was analyzed using the following device: Device: SPS3500DD manufactured by SII Method: ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy)

[0034] (Analysis of Crystalline Phase) A sample (15 mm x 15 mm x 10 mm) was cut out from the sintered body, and the surface of the cut out sample (the surface corresponding to the sputtered surface) was mirror-polished using a slurry abrasive (COMPOL120, manufactured by Fujimi Incorporated). Then, the crystal phase of the sintered body was analyzed using the following equipment. Principle: X-ray diffraction method Equipment: Ultima IV manufactured by Rigaku Corporation Tube: Cu-Kα ray Tube voltage: 40 kV Current: 30 mA Measurement method: 2θ-θ reflection method Scan speed: 40° / min Sampling interval: 0.01° Measurement range (2θ): 10° to 120° Divergence slit: 1° Divergence vertical limiting slit: 10 mm Scattering slit: 8 mm Receiving slit: open state Goniometer: horizontal type for sample Sample measurement location: sputtered cross-section side

[0035] Zn ５ In ２ O ８ The X-ray diffraction peak intensity in the range of 34.1°≦2θ≦35.1° attributed to the Zn phase is designated as I1. ３ In ２ O ６ phase and Zn ４ In ２ O ７The sum of the X-ray diffraction peak intensities of the Zn phase at 34.1°≦θ≦35.1° was taken as I2, and I1 / I2 was calculated. ５ In ２ O ８ The X-ray diffraction peak intensity attributable to the Zn phase (ICDD card number, 01-089-8974) was taken as the maximum peak intensity at 34.74°±0.05°. ３ In ２ O ６ The phase (ICDD card number, 00-020-1439) was determined as the maximum peak intensity at 34.23°±0.05°. ４ In ２ O ７ The phase (ICDD card number, 01-077-8496) was taken as the maximum peak intensity at 34.97°±0.05°.

[0036] (Regarding relative density) The relative density was calculated using the following formula: Relative density (%) = Archimedes density / Calculated density × 100 Archimedes density: A sample (15 mm × 15 mm × 10 mm) was prepared by grinding the sintered body to remove the affected layers on the top, bottom, and outer peripheral surfaces, and the Archimedes density was calculated using the Archimedes method. When the relative density is 94% or less, it is preferable to calculate it using the dimensional density. Calculated density: The sintered body was subjected to a component analysis, and the oxide mass ratio (mass%) of In and Zn was calculated by converting the atomic ratio (at%) of each of the constituent elements In and Zn to a total of 100 at%. ２ O ３ The calculated density was calculated using the following theoretical density of ZnO: Calculated density (g / cm ３ )=(W1+W2) / (W1 / d1+W2 / d2) W1:In ２ O ３ W2: Mass ratio of ZnO (mass%) Theoretical density: d1: 7.18 g / cm ３ (In ２ O ３ Theoretical density) d2: 5.61 g / cm ３ (Theoretical density of ZnO)

[0037] (Regarding the average crystal grain size) A sample (15 mm x 15 mm x 10 mm) was cut from the sintered body, the cut sample surface was polished, and a microstructure photograph of the mirror-polished sample surface (a cross section perpendicular to the surface corresponding to the sputtered surface) was taken using a scanning electron microscope (SEM) at a magnification of 5000 times in six fields. Next, on the photographed image, three or fewer lines (referred to as lines 1, 2, and 3) were drawn so that the number of crystal grains crossed by each line was 10 or more, and the length of each line and the number of crystal grains crossed by each line were determined. At this time, crystal grains whose ends were inside the line were counted as 0.5. Based on the measured length of the lines and the number of crystal grains crossed by each line, the crystal grain size in one field of view was calculated using the following formula. Crystal grain size in one field of view = (length of line 1 / number of crystal grains crossed by line 1 + length of line 2 / number of crystal grains crossed by line 2 + length of line 3 / number of crystal grains crossed by line 3) ÷ 3 Then, for each of the six fields of view, the crystal grain size was calculated using the above formula, and the arithmetic average value of the six fields of view was taken as the average crystal grain size. However, if the number of crystal grains crossed by each line in the field of view is less than 10, a magnification of 2000x or 1000x may be used. The equipment used and measurement conditions were as follows. Equipment used: JXA-8500F (manufactured by JEOL Ltd.) Acceleration voltage: 15.0 kV Beam current: 5.0 x 10 －８ A

[0038] (Volume Resistivity) The surface of the sintered body was polished, and the volume resistivity was measured at any five points on the polished surface spaced at least 1.5 cm apart, and the arithmetic mean value and standard deviation of the five points were calculated. The following equipment was used for the measurement. Equipment: Resistivity Meter Σ-5+ manufactured by NPS Co., Ltd. Method: Constant current application method Method: DC four-probe method Measurement temperature: Room temperature (20 to 25°C)

[0039] (Regarding Vickers Hardness) A sample (15 mm x 15 mm x 10 mm) was cut out from the sintered body, the surface of the cut sample was polished, and the Vickers hardness of the polished surface was measured in accordance with JIS R 1610: 2003. Test method: Vickers hardness test Apparatus: Micro Vickers hardness tester (Mitutoyo HM-200D) Test force: 4.903 N Test temperature: 10 to 35°C Load time: 4 seconds Hold time: 15 seconds Unload time: 4 seconds Approach speed: 60 μm / sec Distance between indentations: At least 4 times the average diagonal length of the indentations The number of tests was 5, and the average value was calculated.

[0040] (Example 1) In ２ O ３ The ZnO powder and the ZnO powder were prepared, weighed and mixed so that the Zn content in the sintered body was 10.7 wt % in terms of ZnO, and then calcined at 1100°C. ５０ After pulverization, the resulting powder was filled into a carbon die and sintered in an argon atmosphere at a maximum temperature of 1150°C under a pressure of 300 kgf / cm. ２ A sintered body (diameter: 210 mm) was produced by hot pressing (HP) sintering under the conditions of 10.7 wt % ZnO, 10.7 wt % ZnO, and 10.7 wt % ZnO. The X-ray diffraction peak intensity ratio I1 / I2 was 0.76. ５ In ２ O ８ The average crystal grain size was 0.77 μm, the relative density was 100.0%, and the volume resistivity was 1.01 mΩ·cm. The Vickers hardness Hv was 699, which showed good hardness.

[0041] (Example 2) In ２ O ３ The ZnO powder and the ZnO powder were prepared, and were weighed and mixed so that the Zn content in terms of ZnO in the sintered body was 10.7 wt %. ５０ The powder was then crushed in a wet bead mill to a particle size of 0.28 μm. After crushing, the resulting powder was filled into a carbon die and sintered in an argon atmosphere at a maximum temperature of 1000° C. under a pressure of 300 kgf / cm.２ A sintered body (diameter: 210 mm) was produced by hot pressing (HP) sintering under the conditions of 10.7 wt % ZnO, 10.7 wt % ZnO, and 10.7 wt % ZnO. The X-ray diffraction peak intensity ratio I1 / I2 was 0.61. ５ In ２ O ８ The average crystal grain size was 0.83 μm, the relative density was 97.5%, and the volume resistivity was 2.12 mΩ·cm. The Vickers hardness Hv was 692, which showed good hardness.

[0042] (Example 3) In ２ O ３ The ZnO powder and the ZnO powder were prepared, weighed and mixed so that the Zn content in the sintered body was 2.5 wt % in terms of ZnO, and then calcined at 1100°C. ５０ After pulverization, the resulting powder was filled into a carbon die and sintered in an argon atmosphere at a maximum sintering temperature of 1150°C and a press pressure of 250 kgf / cm. ２ A sintered body (diameter: 160 mm) was produced by hot pressing (HP) sintering under the conditions of 3 hours of holding time. The physical properties of the sintered body obtained in Example 2 were measured, and the Zn content was 2.5 wt % in terms of ZnO, the X-ray diffraction peak intensity ratio I1 / I2 was 0.53, and the Zn ５ In ２ O ８ The average crystal grain size was 1.30 μm, the relative density was 99.1%, and the volume resistivity was 2.39 mΩ·cm. The Vickers hardness Hv was 714, which showed good hardness.

[0043] (Example 4) In ２ O ３ The ZnO powder and the ZnO powder were prepared, weighed and mixed so that the Zn content in the sintered body was 37 wt % in terms of ZnO, and then calcined at 1100°C. ５０ After pulverization, the resulting powder was filled into a carbon die and sintered in an argon atmosphere at a maximum sintering temperature of 1150°C and a press pressure of 250 kgf / cm.２ A sintered body (diameter: 160 mm) was produced by hot pressing (HP) sintering under the conditions of 1000 kJ / 2000 kcal / min, and 3 hours of holding time. The physical properties of the sintered body obtained in Example 4 were measured, and the Zn content was 37.0 wt % in terms of ZnO, the X-ray diffraction peak intensity ratio I1 / I2 was 1.09, and the Zn ５ In ２ O ８ The phase was the main phase. For reference, the X-ray diffraction patterns of Example 4 are shown in Figures 1 and 2. The average crystal grain size was 0.92 µm, the relative density was 99.0%, and the volume resistivity was 1.17 mΩ cm. The Vickers hardness Hv was 567, which indicated good hardness. The results of Examples 1 to 4 are shown in Table 1.

[0044]

[0045] (Comparative Example 1) In Comparative Example 1, a sintered body was produced under the same conditions as in Example 1, except that the calcination temperature was adjusted to 1210°C. As a result of measuring the physical properties of the sintered body obtained in Comparative Example 1, the Zn content was 10.7 wt% in terms of ZnO, the X-ray diffraction peak intensity ratio I2 / I1 was 0.44, and the Zn ４ In ２ O ７ The Vickers hardness Hv was 653, which was inferior in strength to Example 1 having the same composition.

[0046] (Comparative Example 2) In Comparative Example 2, a sintered body was produced under the same conditions as in Example 2, except that the calcination temperature was adjusted to 1210°C. Measurement of the physical properties of the sintered body obtained in Comparative Example 2 revealed that the Zn content was 2.5 wt% in terms of ZnO, the X-ray diffraction peak intensity ratio I2 / I1 was 0.46, and the Zn ４ In ２ O ７ The Vickers hardness Hv was 690, which was inferior in strength to Example 2 having the same composition.

[0047] (Comparative Example 3) In Comparative Example 3, a sintered body was produced under the same conditions as in Example 3, except that the calcination temperature was adjusted to 1210°C. As a result of measuring the physical properties of the sintered body obtained in Comparative Example 2, the Zn content was 37.0 wt% in terms of ZnO, the X-ray diffraction peak intensity ratio I2 / I1 was 0.37, and the Zn ４ In ２ O ７ The Vickers hardness Hv was 532, which was inferior in strength to Example 3 having the same composition.

[0048] (Comparative Example 4) In ２ O ３ The ZnO powder and the ZnO powder were prepared and weighed so that the Zn content in the sintered body was 10.7 wt % in terms of ZnO. ５０ The slurry was then granulated using a wet bead mill to a particle size of 0.37 μm. The granulated powder was then filled into a die and pressed at a pressure of 785 kfg / cm. ２ , holding time: 1 minute, uniaxial molding, then pressing pressure: 1795 kgf / cm ２ The compact was then subjected to CIP molding at a maximum sintering temperature of 1400°C and a holding time of 1 minute to produce a compact. The compact was then subjected to atmospheric sintering in an air atmosphere at a maximum sintering temperature of 1400°C and a holding time of 10 hours to produce a sintered body. The physical properties of the sintered body obtained in Comparative Example 4 were measured and found to have a Zn content of 10.7 wt% in terms of ZnO, an X-ray diffraction peak intensity ratio I1 / I2 of 0.11, and a Zn content of 10.7 wt% in terms of ZnO. ３ In ２ O ６ The Vickers hardness Hv was 603, which was clearly inferior in strength to Example 1 having the same composition. The results of Comparative Examples 1 to 4 are shown in Table 2.

[0049]

[0050] This disclosure is expected to suppress particles during sputtering, potentially improving product yield. Improving product yield will lead to a stable supply of products and reduced loss of metal raw materials, which are limited resources. Therefore, this disclosure may contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster technological innovation," and Goal 12, "Ensure sustainable consumption and production patterns."

[0051] According to the present disclosure, it is possible to provide a sintered body and a sputtering target containing indium, zinc, and oxygen and having high hardness, as well as a method for producing the sintered body. The sintered body and the sputtering target according to the present disclosure are useful for forming an IZO thin film as a transparent conductive film or an oxide semiconductor film.

Claims

1. An IZO sintered body containing indium, zinc, and oxygen, ２ O ３ phase and Zn ５ In ２ O ８ phase, Zn ５ In ２ O ８ The X-ray diffraction peak intensity of the Zn phase at 34°≦2θ≦35° is designated as I1. ３ In ２ O ６ phase and Zn ４ In ２ O ７ A sintered body having an I1 / I2 ratio of 0.5 or more, where I2 is the sum of the X-ray diffraction peak intensities of the phase at 34.1°≦2θ≦35.1°.

2. The sintered body according to claim 1, wherein the average crystal grain size is 2 μm or less.

3. The sintered body according to claim 1, which has a relative density of 90% or more.

4. The sintered body according to claim 1, which has a volume resistivity of 10 mΩ·cm or less.

5. The sintered body according to claim 1, wherein the Zn content is 1% by mass or more and 37% by mass or less in terms of ZnO.

6. An IZO sputtering target comprising the sintered body according to any one of claims 1 to 5.

7. In ２ O ３ The resulting mixed powder was heated in a vacuum or inert gas atmosphere at 1000°C or higher but lower than 1200°C under a pressure of 150 kgf / cm. ２ A method for producing a sintered body by pressure sintering under the above conditions.

8. The method for producing a sintered body according to claim 7, wherein the mixed powder is calcined at a temperature of 1000° C. or higher but lower than 1200° C., and the calcined powder is pressure sintered.

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