TW202000951A - Oxide sintered body and sputtering target - Google Patents

Abstract

The oxide sintered body according to one aspect of the embodiment is an oxide sintered body which comprises indium, gallium and zinc, wherein it contains a homologous structural compound represented by InGaZnO4 or InGaZn2O5 and a spinel structural compound represented by ZnGa2O4, and its bending strength is 180 MPa or more.

Description

Oxide sintered body and sputtering target

The embodiment disclosed in the present invention relates to an oxide sintered body and a sputtering target.

Conventionally, sputtering targets for forming oxide semiconductor thin films such as IGZO (Indium Gallium Zinc Oxide) are known. The oxide sintering system used in this sputtering target contains a homologous structure compound represented by InGaO ₃ (ZnO) _m (m is an integer of 1 to 20), and a spinel represented by ZnGa ₂ O ₄ ( spinel) structure compound (for example, refer to Patent Document 1).

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2008-163441

However, because the bending strength of the oxide sintered body previously used in the sputtering target is about 50 MPa, when the sputtering target is manufactured using this oxide sintered body, and when the sputtering target is used for sputtering When plating, there is a problem that the oxide sintered body is easily damaged.

An aspect of the embodiment of the present invention is carried out in view of the above circumstances, and an object thereof is to provide an oxide sintered body and a sputtering target capable of suppressing damage.

An exemplary oxide sintered body of an embodiment of the present invention is an oxide sintered body containing indium, gallium, and zinc, which contains a homologous structure compound represented by InGaZnO ₄ or InGaZn ₂ O _{5 and} represented by ZnGa ₂ O ₄ Spinel structure compound, and the bending strength is more than 180MPa.

According to one aspect of the embodiment of the present invention, damage to the oxide sintered body can be suppressed.

Figure 1 is an SEM image of the oxide sintered body of Example 1.

Hereinafter, embodiments of the oxide sintered body and the sputtering target disclosed in this case will be described with reference to the drawings. In addition, the present invention is not limited to the embodiments shown below.

The oxide sintering system of the embodiment includes indium (In), gallium (Ga), and zinc (Zn). For example, the oxide sintering system of the embodiment is composed of indium, gallium, zinc, and oxygen (O), and can be used as a sputtering target.

Furthermore, the compound of the homologous structure represented by the oxide sintering system InGaO ₃ (ZnO) _m (m is an integer) of the embodiment contains InGaZnO ₄ (that is, m=1) or InGaZn ₂ O ₅ (that is, m= 2) The homologous structural compound represented and the spinel structural compound represented by ZnGa ₂ O _{4 have} a bending strength of 180 MPa or more.

Thereby, when the sputtering target is manufactured using such an oxide sintered body, and when sputtering is performed using such a sputtering target, damage to the oxide sintered body can be suppressed.

Furthermore, the oxide sintered body of the embodiment is preferably InGaZnO ₄ (that is, m=1) or InGaZn ₂ O ₅ (that is, in the homologous structure compound represented by InGaO ₃ (ZnO) _m (m is an integer) , M=2) represents the homologous structure compound and the spinel structure compound represented by ZnGa ₂ O ₄ , and the bending strength is 180 MPa or more.

In addition, among the homologous structural compounds represented by InGaO ₃ (ZnO) _m (m is an integer), when the compound contains a homologous structural compound represented by m of 3 or more (for example, InGaZn ₃ O ₆ ), the average area of the homologous structural compound is equivalent The diameter of the circle becomes larger and the bending strength tends to be lower. Therefore, among the homologous structural compounds represented by InGaO ₃ (ZnO) _m (m is an integer), it is preferable that the homologous structural compounds represented by those having m of 3 or more are not contained.

In addition, the bending strength of the oxide sintered body of the embodiment is preferably 190 MPa or more, and more preferably 200 MPa or more. The upper limit of flexural strength is not specified, but it is usually 500 MPa or less.

Furthermore, the oxide sintering system of the embodiment preferably satisfies the following formula (1) to formula (3) in the atomic ratio of each element.

0.08<In/(In+Ga+Zn)<0.31‥(1)

0.35<Ga/(In+Ga+Zn)<0.58‥(2)

0.23<Zn/(In+Ga+Zn)<0.46‥(3)

This can reduce the specific resistance of the oxide sintered body. Therefore, according to the embodiment, when such an oxide sintered body is used as a sputtering target, it is possible to use a low-cost DC power source for sputtering, and the film forming rate can be improved.

Furthermore, the oxide sintering system of the embodiment is preferably such that the atomic ratio of each element satisfies the following formula (4) to formula (6), 0.08<In/(In+Ga+Zn)≦0.20‥(4)

0.40≦Ga/(In+Ga+Zn)<0.58‥(5)

0.25≦Zn/(In+Ga+Zn)<0.46‥(6)

It is better if the atomic ratio of each element satisfies the following formulas (7) to (9), 0.13<In/(In+Ga+Zn)≦0.19‥(7)

0.40≦Ga/(In+Ga+Zn)≦0.55‥(8)

0.27≦Zn/(In+Ga+Zn)<0.46‥(9)

The atomic ratio of each element is better to satisfy the following formula (10) to formula (12), 0.14≦In/(In+Ga+Zn)≦0.19‥(10)

0.41≦Ga/(In+Ga+Zn)≦0.53‥(11)

0.30≦Zn/(In+Ga+Zn)≦0.45‥(12)

The atomic ratio of each element satisfies the following formula (13) to formula (15) is even more preferable.

0.14<In/(In+Ga+Zn)≦0.18‥(13)

0.41≦Ga/(In+Ga+Zn)≦0.52‥(14)

0.31≦Zn/(In+Ga+Zn)≦0.45‥(15)

Therefore, when such an oxide sintered body is used as a sputtering target, the generation of arcing can be reduced.

In addition, the oxide sintered body of the embodiment can contain unavoidable impurities derived from raw materials and the like. The unavoidable impurities in the oxide sintered body of the embodiment include Fe, Cr, Ni, Si, W, Cu, Al, and the like, and the content of these impurities is usually 100 ppm or less.

Further, in the oxide sintering system of the embodiment, in the cross-sectional observation of the sintered body, the average area equivalent circle diameter of the homologous structure compound is preferably 10 μm or less, and the average aspect ratio of the homologous structure compound is preferably 2.0 or less. Thereby, since the crystal structure in the oxide sintered body can be made fine, the bending strength of the oxide sintered body can be improved.

In the oxide sintering system of the embodiment, the average area equivalent circle diameter of the homologous structure compound is preferably 8.0 μm or less, more preferably 7.0 μm or less, still more preferably 6.0 μm or less, and 5.0 μm or less. Better. The lower limit of the equivalent area diameter of the average area of compounds of the same structure is not specifically defined, but it is usually 2.0 μm or more.

Furthermore, the average aspect ratio of the homologous structure compound of the oxide sintered body of the embodiment is preferably 1.9 or less, more preferably 1.8 or less, and still more preferably 1.75 or less. The lower limit value of the average aspect ratio of the homologous structure compound is not specifically defined, but it is usually 1.0 or more.

In the oxide sintering system of the embodiment, in the cross-sectional observation of the sintered body, the average area equivalent spin diameter of the spinel structure compound is preferably 5.0 μm or less, and the average aspect ratio of the spinel structure compound is 2.0 The following is better. Thereby, since the crystal structure in the oxide sintered body can be made fine, the bending strength of the oxide sintered body can be improved.

Furthermore, the oxide sintering system of the embodiment preferably has a spinel structure compound having an average area equivalent circle diameter of 4.5 m or less, more preferably 4.0 m or less, and even more preferably 3.8 m or less. The lower limit value of the average area equivalent circle diameter of the spinel structure compound is not particularly specified, but it is usually 2.0 μm or more.

In addition, in the oxide sintering system of the embodiment, the average aspect ratio of the spinel structure compound is preferably 1.8 or less, more preferably 1.7 or less, and even more preferably 1.6 or less. The lower limit value of the average aspect ratio of the spinel structure compound is not specifically defined, but it is usually 1.0 or more.

Furthermore, the oxide sintering system of the embodiment is preferably such that the area ratio of the spinel structure compound is 15% or more in the cross-sectional observation of the sintered body. As a result, the relative density of the oxide sintered body becomes higher, and the bending strength can be improved.

Moreover, in the oxide sintering system of the embodiment, the area ratio of the spinel structure compound is preferably 25% or more, more preferably 35% or more, more preferably 40% or more, and still more preferably 45% or more .

Furthermore, the oxide sintering system of the embodiment is preferably such that the area ratio of the spinel structure compound is 80% or less. With this, the specific resistance of the oxide sintered body can be reduced.

In addition, the area ratio of the spinel structure compound of the oxide sintered body of the embodiment is preferably 70% or less, more preferably 65% or less, 60% or less is still better, and 55% or less is still better .

Furthermore, the oxide sintering system of the embodiment preferably has a relative density of 99.5% or more. Accordingly, when such an oxide sintered body is used as a sputtering target, the discharge state of DC sputtering can be stabilized.

When the relative density is 99.5% or more, when such an oxide sintered body is used as a sputtering target, the sputtering target can have fewer voids, and it is easy to prevent ingestion of gas components in the atmosphere. Moreover, abnormal sputtering and cracking of the sputtering target, etc., starting from the void are unlikely to occur during sputtering.

Further, the relative density of the oxide sintered body of the embodiment is preferably 99.8% or more, more preferably 100.0% or more, still more preferably 100.5% or more, and still more preferably 101.0% or more. The upper limit of relative density is not specified, but it is usually 105%.

Furthermore, the oxide sintering system of the embodiment preferably has a specific resistance of 5.0×10 ⁻¹ Ω·cm or less. Therefore, when such an oxide sintered body is used as a sputtering target, it is possible to use a low-cost DC power source for sputtering, and the film forming rate can be increased.

In addition, the oxide sintered embodiment system at a specific resistance of 5.0 × 10 ^-2 Ω‧cm is less preferred, the line resistance than 4.0 × 10 ^-2 Ω. cm or less is better, and 3.5×10 ^-2 Ω‧cm or less is even better. The lower limit of the specific resistance is not specified, but it is usually 1.0×10 ^-4 Ω‧cm or more. The specific resistance of the oxide sintered body of the embodiment can be measured in accordance with JIS K 7194.

<Each manufacturing step of oxide sputtering target>

The oxide sputtering target of the embodiment can be produced by, for example, the following method. First, the raw material powders are mixed. The raw material powder is usually In ₂ O ₃ powder, Ga ₂ O ₃ powder and ZnO powder.

The mixing ratio of each raw material powder can be appropriately determined so that the oxide sintered body becomes the required constituent element ratio.

Each raw material powder can also be dry mixed beforehand. The method of this dry mixing is not particularly limited. For example, a ball mill can be used for mixing, and each raw material powder and zirconia balls are added to a pot and mixed. As a method of manufacturing a molded body from the mixed powder thus mixed, for example, a slip casting method (slip casting method), CIP (Cold Isostatic Pressing) and the like can be cited. Next, two methods that are specific examples of the forming method will be described separately.

(Grouting method)

In the grouting molding method described here, molding is performed by preparing a slurry containing mixed powder and an organic additive with a dispersion medium, flowing the slurry into a mold, and removing the dispersion medium. The organic additives that can be used here are well-known binders, dispersants, and the like.

In addition, the dispersion medium used when preparing the slurry is not particularly limited, and can be appropriately selected and used from water, alcohols, etc. according to the purpose. In addition, the method of preparing the slurry is not particularly limited. For example, a ball mill can be used in which a mixed powder, an organic additive, and a dispersion medium are added to a tank and mixed. The slurry obtained in this way flows into a mold, and the dispersion medium is removed to produce a molded body. The molds that can be used here include metal molds, gypsum molds, and resin molds that remove the dispersion medium under pressure.

(CIP method)

The CIP method described here is to prepare a slurry containing a mixed powder and an organic additive with a dispersion medium, and spray-dry the slurry obtained by such slurry into a mold to perform pressure molding. The organic additives that can be used here are well-known binders, dispersants, and the like.

In addition, the dispersion medium used when preparing the slurry is not particularly limited, and can be appropriately selected and used from water, alcohols, etc. according to the purpose. In addition, the method of preparing the slurry is not particularly limited. For example, a ball mill in which a mixed powder, an organic additive, and a dispersion medium are placed in a tank and mixed can be used.

The slurry thus obtained was spray-dried to produce dry powder having a moisture content of 1% or less, and the dry powder was filled into a mold and subjected to pressure molding by the CIP method to produce a molded body.

Next, the obtained molded body is calcined to produce a sintered body. The calcination furnace for manufacturing such a sintered body is not particularly limited, and a calcination furnace that can be used for the production of a ceramic sintered body can be used. Such calcination system may be carried out in the presence of oxygen.

In the present invention, the calcination temperature must be 1450°C or higher, preferably 1480°C or higher. By setting the calcination temperature to 1450° C. or higher, the high-density and high-strength sintered body of the present invention can be obtained. On the other hand, the calcination temperature is preferably 1600°C or lower, and more preferably 1550°C or lower from the viewpoint of suppressing the enlargement of the structure of the sintered body and preventing cracking.

Next, the obtained sintered body is cut. Such cutting processing is performed using a flat grinding disk or the like. Furthermore, the surface roughness Ra after cutting can be appropriately controlled by selecting the size of the abrasive grains of the grinding stone used for cutting.

The sputtered target is manufactured by joining the sintered body after cutting to the base material. The material system of the base material can be appropriately selected from stainless steel, copper, and titanium. Low-melting-point solder such as indium can be used as the bonding material.

[Example]

[Example 1]

The average particle diameter In 0.6μm ₂ O ₃ powder of an average particle size of 1.5μm Ga ₂ O ₃ powder and ZnO powder of an average particle size of 0.8μm dry-mixed by a ball mill for zirconia balls in the groove, and Prepare mixed powder.

The average particle size of the raw material powder was measured using a particle size distribution measuring device HRA manufactured by Nikkiso Co., Ltd. In this measurement, water was used as the solvent system, and the refractive index of the measurement substance was measured at 2.20. In addition, the average particle diameter of the raw material powder described below was also set to the same measurement condition. In addition, the average particle diameter of the raw material powder is the volume cumulative particle diameter D _{50 of 50} % by volume of the cumulative volume by the laser diffraction scattering particle size distribution measurement method.

In addition, in preparation of such mixed powders, each raw material powder is prepared so that the atomic ratio of all metal elements contained in the raw material powder becomes In:Ga:Zn=0.17:0.50:0.33.

Next, add 0.2% by mass of binder to the mixed powder, 0.6% by mass of the dispersant to the mixed powder, and 20% by mass of water to the mixed powder as the dispersion medium in the tank after preparing the mixed powder , And mixed with a ball mill to prepare the slurry.

Next, the prepared slurry was poured into a metal mold sandwiched with a filter, and drained to obtain a molded body. Next, the molded body is calcined to produce a sintered body. The calcination is performed in a gas environment with an oxygen concentration of 20% under the conditions of a calcination temperature of 1500°C, a calcination time of 8 hours, a temperature increase rate of 50°C/hour, and a temperature decrease rate of 50°C/hour.

Next, the obtained sintered body was subjected to cutting processing to obtain an oxide sintered body having a surface roughness Ra of 1.0 μm, a width of 210 mm, a length of 710 mm, and a thickness of 6 mm. In addition, this type of cutting system uses #170 grinding stone.

[Examples 2 and 3]

The oxide sintered body was obtained by the same method as Example 1. In addition, in Examples 2 and 3, when preparing the mixed powder, each raw material powder was prepared so that the atomic ratio of the metal elements contained in all the raw material powders became the atomic ratio described in Table 1.

[Comparative Examples 1 to 4]

The oxide sintered body was obtained by the same method as Example 1. In Comparative Examples 1 to 4, when preparing the mixed powder, each raw material powder was prepared so that the atomic ratio of the metal elements contained in all the raw material powders became the atomic ratio described in Table 1.

In addition, in Examples 1 to 3 and Comparative Examples 1 to 4, each element measured when preparing each raw material powder was measured by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy) The ratio is equal to the ratio of the elements in the obtained oxide sintered body.

Next, the relative density of the oxide sintered bodies of Examples 1 to 3 and Comparative Examples 1 to 4 obtained above was measured. The relative density is determined based on the Archimedes method.

Specifically, the air mass of the oxide sintered body is divided by the volume (water mass of the sintered body/specific gravity of water at the metering temperature), and is calculated relative to the theoretical density ρ(g/cm ³ ) As the relative density (unit: %).

In addition, the theoretical density ρ(g/cm ³ ) is calculated from the mass% and density of the raw material powder used for manufacturing the oxide sintered body. Specifically, it is calculated according to the following formula (7).

ρ={(C ₁ /100)/ρ ₁ +(C ₂ /100)/ρ ₂ +(C ₃ /100)/ρ ₃ } ^-1 ‥(7)

In addition, C ₁ to C ₃ and ρ ₁ to ρ ₃ in the above formula each represent the following values.

‧C ₁ : mass% of In ₂ O ₃ powder used in the production of oxide sintered body

‧Ρ ₁ : In ₂ O ₃ density (7.18g/cm ³ )

‧C ₂ : mass% of Ga ₂ O ₃ powder used for manufacturing oxide sintered body

‧Ρ ₂ : Density of Ga ₂ O ₃ (5.95g/cm ³ )

‧C ₃ : mass% of ZnO powder used for manufacturing oxide sintered body

‧Ρ ₃ : Density of ZnO (5.60g/cm ³ )

Next, the oxide sintered bodies for sputtering targets of Examples 1 to 3 and Comparative Examples 1 to 4 obtained above were each measured for specific resistance (bulk resistance).

Specifically, it uses Loresta (registered trademark) HP MCP-T410 (type 4 probe probe TYPE ESP) manufactured by Mitsubishi Chemical Corporation to contact the probe to the surface of the processed oxide sintered body, and The measurement is performed in the AUTO RANGE mode. The measurement points were set at a total of 5 points in the vicinity of the center and the four corners of the oxide sintered body, and the average value of the measured values was taken as the bulk resistance value of the sintered body.

Next, the oxide sintered bodies for sputtering targets of Examples 1 to 3 and Comparative Examples 1 to 4 obtained above were respectively measured for the bending strength. This bending strength system uses a sample piece (length 36 mm or more, width 4.0 mm, thickness 3.0 mm) cut from an oxide sintered body by wire-cut electrical discharge machining, and is based on JIS-R-1601 (fine ceramic The bending strength test method) was measured by the three-point bending strength measurement method.

Next, X-ray diffraction (X-Ray Diffraction: XRD) measurement was performed on the oxide sintered bodies of Examples 1 to 3 and Comparative Examples 1 to 4 obtained above to obtain X-ray diffraction charts. Furthermore, the constituent phase contained in the oxide sintered body was identified from the obtained X-ray diffraction chart.

In addition, specific measurement conditions for such X-ray diffraction measurement are as follows.

‧Installation: SmartLab (Rigaku Corporation, registered trademark)

‧Line source: CuKα line

‧Tube voltage: 40kV

‧Tube current: 30mA

‧Scanning speed: 5deg/min

‧Displacement: 0.02deg

‧Scanning range: 2θ=20° to 80°

Next, the surface of the oxide sintered body for the sputtering target of Examples 1 to 3 and Comparative Examples 1 to 4 obtained above was observed using a scanning electron microscope (SEM: Scanning Electron Microscope), and the constituent phases and crystals of the crystals were simultaneously crystallized. Evaluation of shape.

Specifically, the oxide sintered body is cut to obtain a cross section, and the cross section is polished in stages using sandpaper #180, #400, #800, #1000, #2000, and finally polished and polished for finishing Become a mirror.

After that, at 40°C, the etching solution [nitric acid (60 to 61% aqueous solution, manufactured by Kanto Chemical Co., Ltd.), hydrochloric acid [35.0 to 37.0% aqueous solution, manufactured by Kanto Chemical Co., Ltd.], and pure water at a volume ratio of HCl: H ₂ O: HNO ₃ =1:1:0.08, mixed in the mixture) and immersed for 2 minutes to etch.

Then, the exposed surface was observed using a scanning electron microscope (SU3500, manufactured by Hitachi HIGHTECHNOLOGIES Co., Ltd.). In addition, the evaluation of the crystal shape was carried out by randomly capturing BSE-COMP images with a magnification of 500 times and a range of 175 μm×250 μm in 10 fields of view, and SEM images of the structure shown in FIG. 1 were obtained.

Figure 1 is an SEM image of the oxide sintered body of Example 1. In addition, in FIG. 1, the lighter-colored crystals are homologous structural compounds, and the darker-colored crystals are spinel structural compounds.

For particle analysis, the image processing software ImageJ 1.51k (http://imageJ.nih.gov/ij/) provided by the National Institutes of Health (NIH) is used.

First, the BSE-COMP image obtained above is drawn along the grain boundaries of the homologous structure compound. After all the drawing is completed, image correction (Image→Adjust→Threshold) is performed to remove the spinel structure compound. The noise remaining after image correction is removed as needed (Process→Noise→Despeckle).

After that, particle analysis (Analyze→Analyze Particles) is performed to obtain the area and aspect ratio of each particle. After that, the area equivalent circle diameter is calculated from the obtained area of each particle. The average values of all the particles calculated in 10 fields of view were defined as the average area equivalent circle diameter and average aspect ratio of the homologous structure compound of the present invention (also described as the IGZO phase in Table 1).

Next, the BSE-COMP image obtained above was drawn along the grain boundaries of the spinel structure compound, and after all the drawing was completed, image correction (Image→Adjust→Threshold) was performed to remove the homologous structure compound. The noise remaining after image correction is removed as necessary (Process→Noise→Despeckle).

After that, particle analysis (Analyze→Analyze Particles) is performed to obtain the area and aspect ratio of each particle. After that, the area equivalent circle diameter is calculated from the obtained area of each particle. The average values of all the particles calculated in 10 fields of view are the average area equivalent circle diameter and average aspect ratio of the spinel structure compound of the present invention (also described as the GZO phase in Table 1).

Here, for the above Examples 1 to 3 and Comparative Examples 1 to 4, the atomic ratio of each element contained in the powder mixture, the relative density of the oxide sintered body, the specific resistance (bulk resistance), the bending strength, the structure The measurement results of the average area equivalent circle diameter and average aspect ratio of the phase, homologous structure compound (IGZO phase) and spinel structure compound (GZO phase) and the area ratio of the spinel structure compound (GZO phase) are shown in Table 1. .

[Table 1]

It can be seen that the relative densities of the oxide sintered bodies of Examples 1 to 3 are all 99.5% or more. Therefore, according to the embodiment, when such an oxide sintered body is used as a sputtering target, the discharge state of DC sputtering can be stabilized.

In addition, it can be seen that the specific resistance of the oxide sintered bodies of Examples 1 to 3 is 5.0×10 ⁻¹ Ωcm or less. Therefore, according to the embodiment, when such an oxide sintered body is used as a sputtering target, sputtering can be performed using a low-cost DC power supply, and the film forming rate can be improved.

Furthermore, it can be seen that the bending strengths of the oxide sintered bodies of Examples 1 to 3 are all 180 MPa or more. Therefore, according to the embodiment, when the sputtering target is manufactured using such an oxide sintered body and when sputtering is performed using such a sputtering target, damage to the oxide sintered body can be suppressed.

In addition, it can be seen that the oxide sintering systems of Examples 1 to 3 contain a homologous structure compound represented by InGaZnO ₄ or InGaZn ₂ O ₅ and a spinel structure compound represented by ZnGa ₂ O ₄ . Therefore, according to the embodiment, an IGZO oxide sintered body with high bending strength can be realized.

Furthermore, from the comparison of Examples 1 to 3 with Comparative Examples 2 and 3, it can be seen that among the homologous compounds represented by InGaO ₃ (ZnO) _m (m is an integer), the homologous compounds represented by m of 3 or more As a result, the bending strength is reduced.

In addition, Examples 1 to 3 containing In, Ga, and Zn in the range shown in the above formulas (1) to (3) at the same time as the compounds of the same structure represented by containing InGaZnO ₄ or InGaZn ₂ O ₅ and not containing In in this range In comparison with Comparative Example 4 of Ga, Zn, it is understood that by containing In, Ga, and Zn in such a range, the specific resistance is reduced to 5.0×10 ⁻¹ Ωcm or less.

Furthermore, comparing Examples 1 to 3 with an area ratio of the spinel structure compound of 80% or less and Comparative Example 4 with an area ratio of the spinel structure compound of more than 80%, it can be seen that by combining the spinel structure compound The area ratio is set to 80% or less, the specific resistance will be reduced.

In addition, it can be seen that the average area equivalent circle diameters of the homologous structure compounds of the oxide sintered systems of Examples 1 to 3 are all 10 μm or less, and the average aspect ratio of the homologous structure compounds is 2.0 or less. Thereby, since the crystal structure in the oxide sintered body can be made fine, the bending strength of the oxide sintered body can be improved.

In addition, it can be seen that the average area equivalent circle diameter of the spinel structure compounds of the oxide sintered systems of Examples 1 to 3 is 5 μm or less, and the average aspect ratio of the spinel structure compounds is 2.0 or less. By this, since the crystal structure in the oxide sintered body can be made fine, the bending strength of the oxide sintered body can be improved.

In addition, it can be seen that the area ratios of the oxide sintered system spinel structure compounds of Examples 1 to 3 are all 15% or more. As a result, the bending strength of the oxide sintered body can be improved.

Next, 10 pieces of the oxide sintered bodies of Examples 1 to 3 and Comparative Examples 1 to 4 were bonded to the substrate using In solder. As a result, no cracks were observed in the oxide sintered bodies of Examples 1 to 3 and Comparative Example 1. On the other hand, in the oxide sintered bodies of Comparative Examples 2 to 4, cracks were observed in 3 pieces, 4 pieces, and 2 pieces, respectively.

Next, the oxide sintered bodies of Examples 1 to 3 and Comparative Examples 2 and 3 were used for sputtering, and the target was evaluated from the amount of arc generation. In addition, the oxide sintering system of Comparative Examples 1 and 4 has a high specific resistance and DC sputtering cannot be performed.

(Sputtering conditions)

Device: DC magnetron sputtering (magnetron sputtering) device, exhaust cryopump, rotary pump

Vacuum reached: 3×10 ^-6 Pa

Sputtering pressure: 0.4Pa

Oxygen partial pressure: 1×10 ^-3 Pa

Power input time: 2W/cm ²

Time: 10 hours

(Arc Counter)

Type: μArc Moniter MAM Genesis MAM Data Collector Ver.2.02 (manufactured by LANDMARK TECHNOLOGY)

(Arc Assessment)

A: 20 times or less

B: 21 to 50 times

C: 51 to 100 times

D: more than 101 times

In addition, after sputtering, the cracking of the oxide sintered body was also confirmed. The above evaluation results are shown in Table 2.

It can be seen that the atomic ratios of the elements are Examples 1 and 2 satisfying formulas (7) to (9). Compared to the atomic ratios of the elements, the atomic ratios are Comparative Examples 2 and 3 that do not satisfy formulas (7) to (9). , By the atomic ratio of each element satisfying formulas (7) to (9) to reduce the occurrence of arc and oxide sintered body cracks.

In addition, it can be seen that the atomic ratio of each element is that Example 1 that satisfies formulas (13) to (15) is compared to Example 2 where the atomic ratio of each element does not satisfy formulas (13) to (15). The atomic ratio satisfies equations (13) to (15) to further reduce the generation of arcs.

The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and various changes can be made as long as they do not depart from the gist of the present invention. For example, the embodiment discloses an example of manufacturing a sputtering target using a plate-shaped oxide sintered body, but the shape of the oxide sintered body is not limited to a plate shape, and may be any shape such as a cylindrical shape.

Those with ordinary knowledge in the technical field can easily derive further effects and modifications. Therefore, the broader aspect of the present invention is not limited to the specific detailed and representative embodiments shown and described above. Therefore, various changes can be made without departing from the spirit or scope of the omnipresent invention concept defined in the scope of the attached patent application and its equivalents.

Claims (16)

An oxide sintered body, which is an oxide sintered body containing indium, gallium, and zinc; wherein it contains a homologous structure compound represented by InGaZnO ₄ or InGaZn ₂ O ₅ and a spinel structure compound represented by ZnGa ₂ O ₄ ; The bending strength is above 180MPa. The oxide sintered body as described in item 1 of the patent application, wherein the atomic ratio of each element satisfies the following formula; 0.08<In/(In+Ga+Zn)<0.31 0.35<Ga/(In+Ga+ Zn)<0.58 0.23<Zn/(In+Ga+Zn)<0.46. The oxide sintered body as described in item 1 or 2 of the patent application, wherein the atomic ratio of each element satisfies the following formula; 0.08<In/(In+Ga+Zn)≦0.20 0.40≦Ga/(In+ Ga+Zn)<0.58 0.25≦Zn/(In+Ga+Zn)<0.46. The oxide sintered body as described in item 1 or 2 of the patent application, wherein the atomic ratio of each element satisfies the following formula: 0.13<In/(In+Ga+Zn)≦0.19 0.40≦Ga/(In+ Ga+Zn)≦0.55 0.27≦Zn/(In+Ga+Zn)<0.46. The oxide sintered body as described in item 1 or 2 of the patent application, wherein the atomic ratio of each element satisfies the following formula: 0.14≦In/(In+Ga+Zn)≦0.19 0.41≦Ga/(In+ Ga+Zn)≦0.53 0.30≦Zn/(In+Ga+Zn)≦0.45. The oxide sintered body as described in item 1 or 2 of the patent application, wherein the atomic ratio of each element satisfies the following formula: 0.14<In/(In+Ga+Zn)≦0.18 0.41≦Ga/(In+ Ga+Zn)≦0.52 0.31≦Zn/(In+Ga+Zn)≦0.45. The oxide sintered body as described in item 1 or 2 of the patent application range, wherein the average area equivalent circle diameter of the homologous structure compound is 10 μm or less. The oxide sintered body according to item 1 or 2 of the patent application range, wherein the average aspect ratio of the homologous structure compound is 2.0 or less. The oxide sintered body as described in item 1 or 2 of the patent application range, wherein the average area equivalent circle diameter of the spinel structure compound is 5 μm or less. The oxide sintered body as described in item 1 or 2 of the patent application, wherein the average aspect ratio of the spinel structure compound is 2.0 or less. The oxide sintered body as described in item 1 or 2 of the patent application, wherein the area ratio of the spinel structure compound is 15% or more. The oxide sintered body as described in item 1 or 2 of the patent application, wherein the area ratio of the spinel structure compound is 80% or less. The oxide sintered body as described in item 1 or 2 of the scope of patent application, wherein the relative density is 99.5% or more. The oxide sintered body as described in item 1 or 2 of the patent application, wherein the specific resistance is 5.0×10 ^-1 Ωcm or less. The oxide sintered body as described in item 1 or 2 of the patent application scope is composed of a homologous structure compound represented by InGaZnO ₄ or InGaZn ₂ O ₅ and a spinel structure compound represented by ZnGa ₂ O ₄ . A sputtering target uses the oxide sintered body according to any one of patent application items 1 to 15 as a target material.

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