KR102380914B1 - Oxide sintered body, sputtering target and manufacturing method of oxide thin film - Google Patents

Abstract

The oxide sintered compact which concerns on one aspect of embodiment is an oxide sintered compact which contains indium, gallium, and zinc in the ratio which satisfy|fills the following formula|equation (1) - (3), It is comprised from a single-phase crystal phase, The average particle diameter of a crystal phase This is 15.0 µm or less.

Description

Oxide sintered body, sputtering target and manufacturing method of oxide thin film

The disclosed embodiment relates to an oxide sintered body, a sputtering target, and a method for manufacturing an oxide thin film.

The sputtering method, which is a method of forming a thin film using a sputtering target, is very effective as a manufacturing method for forming a thin film with a large area and with high precision, and the sputtering method is widely used in display devices such as liquid crystal displays. In recent years, in the field of semiconductor layer technology such as thin film transistors (hereinafter also referred to as "TFT"), oxide semiconductors represented by In-Ga-Zn composite oxides (hereinafter also referred to as "IGZO") are attracting attention instead of amorphous silicon. , the sputtering method is utilized also about formation of an IGZO thin film (for example, refer patent document 1).

In such a sputtering method, when abnormal discharge etc. generate|occur|produce, problems, such as quality abnormality of the thin film formed and generation|occurrence|production of the crack of the sputtering target during sputtering, may arise. As one of the methods for avoiding such problems, there is a method of increasing the density of the sputtering target.

Moreover, even in a high-density target, abnormal discharge may generate|occur|produce. For example, if the crystalline phase constituting the target is multiphase, and there is a difference in resistance between the different crystalline phases, there is a risk of abnormal discharge occurring.

When using an IGZO thin film for the semiconductor layer of TFT, according to the ratio of In, Ga, and Zn, the semiconductor characteristic changes greatly, and various ratio is examined. For example, in patent document 2, the ratio from which the ratio of each metal element becomes In<Ga<Zn is examined. The ratio of In, Ga, and Zn of the IGZO sputtering target can be suitably adjusted so that predetermined semiconductor characteristics may be obtained. For example, as an IGZO sputtering target, _the target which shows _the homologous crystal structure represented by _InGaZnO4 or _In2Ga2ZnO7 is examined.

On the other hand, in the IGZO sputtering target containing much Zn, the target which consists of a _double phase of a homologus crystal structure and the spinel structure of _Ga2ZnO4 is also examined (for example, refer patent document 3).

However, since Ga ₂ ZnO ₄ has a higher resistance compared to a homologous crystal structure and the like, there is a high risk of abnormal discharge occurring. Therefore, as a sputtering target, it is preferable that it is a single phase of a homologus crystal structure.

On the other hand, the high-density sputtering target composed of a single phase tends to have an enlarged crystal grain size as compared with a sputtering target composed of multiple phases. And when a crystal grain size enlarges, the mechanical strength of a sputtering target will fall, and a crack may generate|occur|produce during sputtering.

It is also important that the sputtering target has a uniform distribution of the properties in the sputtering surface. When distribution of a density, etc. is non-uniform|heterogenous in a surface, generation|occurrence|production of an abnormal discharge, a crack during sputtering, etc. may generate|occur|produce. In the case of an IGZO sputtering target, the nonuniformity of the characteristic distribution of a sputtering surface may appear as light and shade of a color difference.

Japanese Patent Laid-Open No. 2007-73312 Japanese Patent Laid-Open No. 2017-145510 Japanese Patent Laid-Open No. 2008-163441

One aspect of embodiment is made in view of the above, and it aims at providing the sputtering target which can perform sputtering stably, and the oxide sintered compact for manufacturing the same.

The oxide sintered compact which concerns on one aspect of embodiment is an oxide sintered compact which contains indium, gallium, and zinc in the ratio which satisfy|fills the following formula|equation (1) - (3), It is comprised in a single-phase crystal phase, The average particle diameter of the said crystal phase This is 15.0 µm or less.

According to one aspect of the embodiment, sputtering can be stably performed.

BRIEF DESCRIPTION OF THE DRAWINGS It is an SEM image (50 times) of the oxide sintered compact in Example 1. FIG.
2 is an SEM image (500 times) of the oxide sintered body in Example 1. FIG.
3 is an SEM image (500 times) of the oxide sintered body in Comparative Example 2. FIG.
4 is an X-ray diffraction chart of the oxide sintered body in Example 1. FIG.
FIG. 5 is a diagram comparing the peak positions in the X-ray diffraction chart of the oxide sintered body in Example 1 and the X-ray diffraction chart of InGaZnO ₄ , In ₂ Ga ₂ ZnO ₇ and Ga ₂ ZnO ₄ .

EMBODIMENT OF THE INVENTION Hereinafter, with reference to an accompanying drawing, embodiment of the manufacturing method of the oxide sintered compact which this application discloses, a sputtering target, and an oxide thin film is described. In addition, this invention is not limited by embodiment demonstrated below.

The oxide sintered compact of embodiment is an oxide sintered compact containing indium (In), gallium (Ga), and zinc (Zn), and can be used as a sputtering target.

The oxide sintered compact of embodiment is comprised from a single-phase crystal phase, and the average particle diameter of the said crystal phase is 15.0 micrometers or less. Thereby, the flexural strength of such an oxide sintered compact can be raised. Moreover, when grinding such an oxide sintered compact, it is easy to obtain a smooth surface at the point which can suppress that the surface becomes rough by peeling of the enlarged particle|grains on the surface.

Moreover, as for the oxide sintered compact of embodiment, it is preferable that an average particle diameter is 10.0 micrometers or less, It is more preferable that it is 8.0 micrometers or less, It is still more preferable that it is 6.0 micrometers or less, It is still more preferable that it is 5.0 micrometers or less. In addition, although the lower limit in particular of an average particle diameter is not set, it is 1.0 micrometer or more normally.

Moreover, since such an oxide sintered compact is comprised by the single-phase crystal phase, distribution of each element in an oxide sintered compact can be made uniform. Therefore, according to embodiment, distribution of each element in the film|membrane of the sputtering film-formed oxide semiconductor thin film can be made uniform.

Moreover, in the oxide sintered compact of embodiment, the atomic ratio of each element satisfy|fills the following formula|equation (1) - (3).

Thereby, when it uses for TFT, the suitable semiconductor layer is obtained.

Further, in the oxide sintered body of the embodiment, it is preferable that the atomic ratio of each element satisfies the following formulas (4) to (6),

It is more preferable that the atomic ratio of each element satisfy|fills the following formula|equation (7) - (9).

In addition, the oxide sintered compact of embodiment may contain the unavoidable impurity derived from a raw material etc. Fe, Cr, Ni, Si, W, Cu, Al, etc. are mentioned as an unavoidable impurity in the oxide sintered compact of embodiment, Their content is 100 ppm or less respectively normally, respectively.

Moreover, in the chart obtained by X-ray diffraction measurement (CuKα ray) of the single-phase crystalline phase constituting the oxide sintered body of the embodiment, it is preferable that diffraction peaks are observed in the following regions A to P.

A. 24.5° to 26.0°

B. 31.0° to 32.5°

C. 32.5° to 33.2°

D. 33.2° to 34.0°

E. 34.5° to 35.7°

F. 35.7° to 37.0°

G. 38.0° to 39.2°

H. 39.2° to 40.5°

I. 43.0° to 45.0°

J. 46.5° to 48.5°

K. 55.5° to 57.8°

L. 57.8° to 59.5°

M. 59.5° to 61.5°

N. 65.5° to 68.0°

O. 68.0° to 69.0°

P. 69.0° to 70.0°

Thereby, when such an oxide sintered compact is used for a sputtering target, it can suppress that abnormal discharge generate|occur|produces. Therefore, according to the embodiment, the production yield of the TFT can be improved in that the generation of particles due to such abnormal discharge can be suppressed.

Moreover, as for the oxide sintered compact of embodiment, it is preferable that a relative density is 97.0 % or more. Thereby, when such an oxide sintered compact is used as a sputtering target, the discharge state of DC sputtering can be stabilized. Moreover, as for the oxide sintered compact of embodiment, it is more preferable that a relative density is 98.0 % or more, and it is still more preferable that a relative density is 99.0 % or more.

If the relative density is 97.0% or more, when such an oxide sintered compact is used as a sputtering target, voids can be decreased in the sputtering target, and introduction of a gas component in the air is easily prevented. Moreover, it becomes difficult to generate|occur|produce the abnormal discharge using such a space|gap as a starting point, cracking of a sputtering target, etc. during sputtering.

Moreover, it is preferable that the flexural strength of the oxide sintered compact of embodiment is 40 Mpa or more. Thereby, when manufacturing a sputtering target using such an oxide sintered compact, or sputtering with such a sputtering target, it can suppress that an oxide sintered compact is damaged.

Moreover, as for the oxide sintered compact of embodiment, it is more preferable that flexural strength is 50 MPa or more, It is still more preferable that it is 60 MPa or more, It is still more preferable that it is 70 MPa or more. In addition, although the upper limit in particular of flexural strength is not set, it is 300 Mpa or less normally.

Moreover, it is preferable that the maximum height Ry of surface roughness of the oxide sintered compact used for the sputtering target of embodiment is 15.0 micrometers or less. Thereby, when sputtering using such a sputtering target, it can suppress that a nodule generate|occur|produces on the target surface.

Moreover, as for the oxide sintered compact used for the sputtering target of embodiment, it is more preferable that maximum height Ry is 11.0 micrometer or less, It is more preferable that it is 10.0 micrometer or less. In addition, although the lower limit in particular of the maximum height Ry is not set, it is 0.1 micrometer or more normally.

Moreover, as for the oxide sintered compact of embodiment, it is preferable that a specific resistance is 40 mohm*cm or less. Thereby, when such an oxide sintered compact is used as a sputtering target, sputtering using an inexpensive DC power supply becomes possible, and a film-forming rate can be improved. Moreover, by this, generation|occurrence|production of an abnormal discharge can be suppressed.

Moreover, as for the oxide sintered compact of embodiment, it is more preferable that specific resistance is 35 mΩ*cm or less, It is more preferable that specific resistance is 30 mΩ*cm or less. In addition, although the lower limit of a specific resistance is not specifically defined, Usually, it is 0.1 mohm*cm or more.

Moreover, as for the sputtering target of embodiment, it is preferable that color difference (DELTA)E ^* of the sputtering target surface is 10 or less. Moreover, it is preferable that ΔE ^* of the color difference in the depth direction of the sputtering target is 10 or less. When this numerical value satisfy|fills the said condition, since there is no bias in a crystal grain size or a composition, it is suitable as a sputtering target.

Moreover, as for the sputtering target of embodiment, it is more preferable that color difference (DELTA)E ^* of the whole surface and the depth direction is 9 or less, It is more preferable that color difference (DELTA)E ^* is 8 or less.

<Each manufacturing process of an oxide sputtering target>

The oxide sputtering target of embodiment can be manufactured by the method demonstrated below, for example. First, the raw material powder is mixed. _As raw material powder, they are In2O3 powder, _Ga2O3 powder, _and ZnO powder normally _.

The mixing ratio of each raw material powder is suitably determined so that it may become a desired structural element ratio in an oxide sintered compact.

It is preferable to dry-mix each raw material powder beforehand. There is no particular limitation on the dry mixing method, and various mixers such as a container rotary mixer and a container fixed mixer can be used for mixing. Among them, it is preferable to mix with, for example, a high-speed mixer manufactured by Earth Technica Co., Ltd. from the viewpoint that high-speed dispersion and mixing can be performed by applying shear force and impact force to the raw material powder. When the raw material powder is uniformly dispersed and mixed by performing the dry mixing treatment in this way, it is preferable to obtain a sintered body having a single-phase structure and the color difference is within the above-mentioned range.

As a method of manufacturing a molded object from the mixed powder mixed in this way, a slip casting method, CIP (Cold Isostatic Pressing: Cold isostatic pressing method), etc. are mentioned, for example. Then, as a specific example of a shaping|molding method, two types of methods are demonstrated, respectively.

(Slip cast method)

In the slip casting method described herein, a slurry containing mixed powder and an organic additive is prepared using a dispersion medium, the slurry is poured into a mold, and the dispersion medium is removed to perform molding. The organic additive which can be used here is a well-known binder, a dispersing agent, etc.

In addition, there is no restriction|limiting in particular in the dispersion medium used when preparing a slurry, According to the objective, it can select suitably from water, alcohol, etc. and can use it. In addition, there is no restriction|limiting in particular also in the method of preparing a slurry, For example, the ball mill mixing which puts mixed powder, an organic additive, and a dispersion medium into a pot and mixes can be used. Thus, the obtained slurry is poured into a mold, a dispersion medium is removed, and a molded object is produced. The molds usable here are metal molds, gypsum molds, resin molds in which the dispersion medium is removed by pressurization, and the like.

(CIP method)

In the CIP method described here, a slurry containing a mixed powder and an organic additive is prepared using a dispersion medium, and the dry powder obtained by spray-drying the slurry is filled in a mold, and press-molding is performed. The organic additive which can be used here is a well-known binder, a dispersing agent, etc.

In addition, there is no restriction|limiting in particular in the dispersion medium used when preparing a slurry, According to the objective, it can select suitably from water, alcohol, etc. and can use it. In addition, there is no restriction|limiting in particular also in the method of preparing a slurry, For example, ball mill mixing in which mixed powder, organic additive, and a dispersion medium are put into a pot and mixed can be used.

The slurry thus obtained is spray-dried to produce a dry powder having a moisture content of 1% or less, and this dry powder is filled in a die and press-molded by the CIP method to produce a molded article.

Next, the obtained molded object is baked, and a sintered compact is produced. There is no particular limitation on the sintering furnace for producing such a sintered body, and any kiln usable for manufacturing the ceramic sintered body can be used.

The calcination temperature is 1350°C to 1580°C, preferably 1400°C to 1550°C, and more preferably 1450°C to 1550°C. The higher the firing temperature, the higher the density of the sintered body is obtained, while it is preferable to control the temperature below the above temperature from the viewpoint of suppressing the enlargement of the structure of the sintered body and preventing cracking. Moreover, since it becomes difficult to form a single-phase crystal phase that a calcination temperature is less than 1350 degreeC, it is unpreferable.

Next, the obtained sintered compact is cut. Such cutting is performed using a surface grinding machine or the like. In addition, the maximum height Ry of the surface roughness after cutting can be appropriately controlled by selecting the size of the abrasive grains of the grindstone used for cutting. is getting bigger

A sputtering target is produced by joining the cut-processed sintered compact to a base material. As the material of the base material, stainless steel, copper, titanium, or the like can be appropriately selected. A low-melting-point solder such as indium can be used for the bonding material.

Example

[Example 1]

Dry mixing of In ₂ O ₃ powder having an average particle diameter of 0.6 μm, Ga ₂ O ₃ powder having an average particle diameter of 1.5 μm, and ZnO powder having an average particle diameter of 0.8 μm using a high-speed mixer manufactured by Earth Technica Co., Ltd. A mixed powder was prepared.

In addition, the average particle diameter of raw material powder was measured using the particle size distribution analyzer (HRA) by the Nikkiso Corporation. In this measurement, water was used as a solvent, and the measurement material was measured with a refractive index of 2.20. In addition, it was set as the same measurement conditions also about the average particle diameter of the raw material powder described below. In addition, the average particle diameter of raw material powder is volume cumulative particle diameter D50 in ₅₀ volume% of cumulative volumes by the laser diffraction scattering type particle size distribution measuring method.

In addition, when preparing such a mixed powder, the atomic ratios of the metal elements contained in all raw material powders are In/(In+Ga+Zn)=0.1, Ga/(In+Ga+Zn)=0.3, Zn/(In+) Each raw material powder was mix|blended so that Ga+Zn)=0.6.

Next, to the pot in which the mixed powder was prepared, 0.2 mass % of a binder with respect to the mixed powder, a 0.6 mass % of a dispersing agent with respect to the mixed powder, and 20 mass % of water with respect to the mixed powder are added, and the mixture is ball milled and mixed. A slurry was prepared.

Next, the prepared slurry was poured into a metal mold fitted with a filter, and drained to obtain a molded product. Next, this compact was fired to produce a sintered compact. This firing was performed at a firing temperature of 1500°C, a firing time of 10 hours, a temperature increase rate of 100°C/h, and a temperature decrease rate of 100°C/h.

Next, the obtained sintered compact was cut and the sputtering target of width 210mm x length 710mm x thickness 6mm was obtained. In addition, #170 grindstone was used for this cutting process.

[Examples 2 to 3]

A sputtering target was obtained using the method similar to Example 1. In Examples 2 to 3, each raw material powder was blended so that the atomic ratios of the metal elements contained in all the raw material powders were the atomic ratios shown in Table 1 at the time of preparing the mixed powder.

[Comparative Examples 1 to 3]

In Comparative Examples 1 to 3, in the preparation of the mixed powder, the atomic ratio of the metal elements contained in all the raw powders is In/(In+Ga+Zn)=0.1, Ga/(In+Ga+Zn)=0.3, Zn/ Each raw material powder was mix|blended so that it might become (In+Ga+Zn)=0.6. In addition, the firing temperature was made to be the temperature shown in Table 1, and in Comparative Example 2, dry mixing was not performed. Other than that, the sputtering target was obtained using the method similar to Example 1.

In addition, in Examples 1 to 3 and Comparative Examples 1 to 3, it was confirmed that the atomic ratio of each metal element measured when manufacturing each raw material powder was the same as the atomic ratio of each metal element in the obtained oxide sintered body. . The atomic ratio of each metal element in the oxide sintered body can be measured, for example, by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy: Inductively Coupled Plasma Atomic Emission Spectroscopy).

Then, about the sputtering target of Examples 1-3 and Comparative Examples 1-3 obtained above, the measurement of the relative density was performed. This relative density was measured based on the Archimedes method.

Specifically, the air mass of the sputtering target was divided by the volume (mass in water of the sintered body / specific gravity of water at the measured temperature), and the value of the percentage with respect to the theoretical density ρ (g/cm 3 ) was taken as the relative density (unit: %) .

In addition, this theoretical density (rho) (g/cm<3>) was computed from the mass % and density of the raw material powder used for manufacture of an oxide sintered compact. Specifically, it computed by following formula (10).

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

·C ₁ : Mass % of In ₂ O ₃ powder used for production of oxide sintered body

·ρ ₁ : Density of In ₂ O ₃ (7.18 g/cm 3 )

_-C2 : mass % _{of Ga2O3} powder used for manufacture of an oxide sintered compact

·ρ ₂ : Ga ₂ O ₃ Density (5.95 g/cm 3 )

C ₃ : Mass % of the ZnO powder used for the production of the oxide sintered body

ρ ₃ : Density of ZnO (5.60 g/cm 3 )

Then, the specific resistance (bulk resistance) was measured about the sputtering target of Examples 1-3 and Comparative Examples 1-3 obtained above, respectively.

Specifically, using a Mitsubishi Chemical Co., Ltd. Loresta (registered trademark) HP MCP-T410 (series 4 probe probe TYPE ESP), the probe was placed on the surface of the processed oxide sintered body, and measurement was performed in AUTO RANGE mode. . The measurement locations were made into a total of 5 locations near the center and four corners of the oxide sintered body, and the average value of each measurement value was taken as the bulk resistance value of the sintered body.

Then, about the sputtering target of Examples 1-3 and Comparative Examples 1-3 obtained above, the flexural strength was measured, respectively. Such flexural strength was measured using a sample piece cut out from an oxide sintered body by wire electric discharge machining (over 36 mm in total length, 4.0 mm in width, and 3.0 mm in thickness) according to JIS-R-1601 (Bending strength test method for fine ceramics). It measured according to the measuring method of three-point bending strength.

Here, with respect to Examples 1 to 3 and Comparative Examples 1 to 3 described above, the atomic ratio of each element contained in the mixed powder, the presence or absence of dry mixing at the time of manufacturing the oxide sintered body, the firing temperature, the relative density of the oxide sintered body, Table 1 shows the measurement results of specific resistance (bulk resistance) and flexural strength.

It turns out that all of the oxide sintered compacts of Examples 1-3 have a relative density of 97.0 % or more. Therefore, according to embodiment, when such an oxide sintered compact is used as a sputtering target, the discharge state of DC sputtering can be stabilized.

In addition, it can be seen that the oxide sintered compacts of Examples 1 to 3 have a specific resistance of 40 mΩ·cm or less. Therefore, according to embodiment, when an oxide sintered compact is used as a sputtering target, sputtering using an inexpensive DC power supply becomes possible, and a film-forming rate can be improved.

Moreover, it turns out that the flexural strength of all of the oxide sintered compacts of Examples 1-3 is 40 MPa or more. Therefore, according to embodiment, when manufacturing a sputtering target using such an oxide sintered compact, or sputtering with such a sputtering target, it can suppress that an oxide sintered compact is damaged.

Then, while observing the surfaces of the sputtering targets of Examples 1-3 and Comparative Examples 1-3 obtained above using a scanning electron microscope (SEM: Scanning Electron Microscope), measurement of the average particle diameter of crystals was done.

Specifically, the cut surface obtained by cutting the oxide sintered body was polished step by step using emery paper #180, #400, #800, #1000, #2000, and finally buffed to finish the mirror surface.

Then, 40 ° C. 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 in a volume ratio of HCl:H ₂ It was etched by immersion in ₀ :HNO3=mixed in a ratio of 1:1:0.08) for 2 minutes.

And the exposed surface was observed using the scanning electron microscope (SU3500, Hitachi High-Technologies Co., Ltd. product). In the measurement of the average particle diameter, BSE-COMP images with a magnification of 500 times and a range of 175 µm × 250 µm were randomly taken in 10 fields to obtain an SEM image of the tissue.

In addition, the image processing software Image J 1.51k (http://imageJ.nih.gov/ij/) provided by the US National Institutes of Health (NIH) was used for particle analysis.

First, drawing was performed along the grain boundary, and after all drawing was completed, image correction (Image→Adjust→Threshold) was performed, and noise remaining after image correction was removed (Process→Noise→Despeckle) as needed.

Thereafter, particle analysis was performed (Analyze → Analyze Particles) to obtain the area in each particle, and then the area equivalent to a circle diameter was calculated. The average value of the diameters per area circle of all the particles calculated in 10 fields of view was taken as the average particle diameter in the present invention.

1 and 2 are SEM images of the oxide sintered body in Example 1. FIG. In addition, in FIG. 1 and FIG. 2, the part shown in black is the chipping part by surface polishing. 1 and 2, it turns out that the oxide sintered compact of Example 1 is comprised by the single-phase crystal phase.

3 is an SEM image of the oxide sintered body in Comparative Example 2. FIG. In addition, in FIG. 3, the part seen in black is the phase (In poor phase) in which indium is small. As shown in FIG. 3, it turns out that the oxide sintered compact of Comparative Example 2 is comprised by the crystalline phase of multiple phases.

Then, about the oxide sintered compact of Examples 1-3 and Comparative Examples 1-3 obtained above, X-ray diffraction (XRD) measurement was performed, respectively, and the X-ray-diffraction chart was obtained.

In addition, the specific measurement conditions of this X-ray diffraction measurement were as follows.

・Device: SmartLab (manufactured by Rigaku Co., Ltd., registered trademark)

・Source: CuKα radiation

·Tube voltage: 40kV

·Tube current: 30mA

Scan speed: 5deg/min

·Step: 0.02deg

Scanning range: 2θ = 20 degrees to 70 degrees

4 is an X-ray diffraction chart of the oxide sintered body in Example 1. FIG. As shown in FIG. 4 , in the X-ray diffraction chart of Example 1, diffraction peaks are observed in the following regions A to P in the range where the diffraction angle 2θ is 20° to 70°.

A. 24.5° to 26.0°

B. 31.0° to 32.5°

C. 32.5° to 33.2°

D. 33.2° to 34.0°

E. 34.5° to 35.7°

F. 35.7° to 37.0°

G. 38.0° to 39.2°

H. 39.2° to 40.5°

I. 43.0° to 45.0°

J. 46.5° to 48.5°

K. 55.5° to 57.8°

L. 57.8° to 59.5°

M. 59.5° to 61.5°

N. 65.5° to 68.0°

O. 68.0° to 69.0°

P. 69.0° to 70.0°

As described above, since the oxide sintered body of Example 1 is composed of a single-phase crystal phase, it can be seen that the diffraction peaks observed in the regions A to P are attributed to such a single-phase crystal phase. In other words, the single-phase crystal phase constituting the oxide sintered body of Example 1 can be identified from the chart obtained by this X-ray diffraction measurement.

5 : is a figure which compares the X-ray diffraction chart of the oxide sintered compact in Example ₁ , and the peak position _in the X _- ray diffraction chart _{of InGaZnO4} , In2Ga2ZnO7, and _Ga2ZnO4 .

As shown in FIG. 5 , the single-phase crystal phase constituting the oxide sintered body of Example 1 has a diffraction peak at a different peak position from the known crystal phases (here, InGaZnO ₄ , In ₂ Ga ₂ ZnO ₇ and Ga ₂ ZnO ₄ ). It can be seen that is observed. Here, the "known crystalline phase" means "a crystalline phase in which the peak position of the X-ray diffraction chart is registered in the JCPDS (Joint Committee of Powder Diffraction Standards) card".

That is, it can be seen that the single-phase crystalline phase constituting the oxide sintered body of Example 1 is a hitherto unknown crystalline phase.

Then, about the sputtering target of Examples 1-3 and Comparative Examples 1-3 obtained above, the maximum height Ry of surface roughness was measured, respectively. Specifically, the maximum height Ry of the sputtering surface was measured using a surface roughness meter (SJ-210/manufactured by Mitsutoyo Corporation). Ten places of the sputtering surface were measured, and the maximum value was made into the maximum height Ry of the sputtering target. A measurement result is shown in Table 2.

Then, in the sputtering targets of Examples 1-3 and Comparative Examples 1-3 obtained above, the color difference ΔE ^* in the surface and the color difference ΔE ^* in the depth direction were measured, respectively. In addition, "color difference ΔE ^* " is an index that quantifies the difference between two colors.

The maximum color difference ΔE ^* within this surface is measured by using a colorimeter (Konica Minolta Co., Ltd., Chromatic Colorimeter CP-300) at intervals of 50 mm in the x-axis and y-axis directions of the surface of the sputtering target that has been cut. The L value, a value, and b value of each point were evaluated in the CIE1976 space. Then, from the differences ΔL, Δa, and Δb between the L values, a values, and b values of two points among the measured points, the color difference ΔE ^* is obtained from the following equation (11) by combining all the two points, and the obtained plurality of color differences ΔE The maximum value of ^* was made into the maximum color difference ΔE ^* within the surface.

In addition, the maximum color difference ΔE ^* in the depth direction is cut by 0.5 mm at an arbitrary location of the cut sputtering target, and measured using a colorimeter at each depth up to the center of the sputtering target, and each point measured The L value, a value, and b value of were evaluated in the CIE1976 space. Then, the color difference ΔE ^* is obtained from the differences ΔL, Δa, and Δb between the L value, a value, and b value of two points among the measured points by combining all two points, and the maximum value of the obtained plurality of color differences ΔE ^* is the maximum value in the depth direction. It was set as color difference (DELTA)E ^* .

Here, in order to evaluate the target from the amount of arcing (abnormal discharge) generated, the sputtering targets obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were applied to a copper substrate using indium, a low melting point solder, as a bonding material. was joined.

Then, sputtering was performed using the sputtering target of Examples 1-3 and Comparative Examples 1-3, and the target was evaluated from the generation amount of arcing (abnormal discharge). Table 2 shows the evaluation results.

(arcing evaluation)

A: Very few.

B: A lot.

C: A lot.

Here, with respect to Examples 1 to 3 and Comparative Examples 1 to 3 described above, the atomic ratio of each element contained in the mixed powder, and the maximum height Ry of the crystal phase, average particle size, and surface roughness of the oxide sintered body used in the sputtering target , the maximum color difference ΔE ^* in the in-plane direction, the maximum color difference ΔE ^* in the depth direction, and the measurement results of the arcing evaluation are shown in Table 2.

It can be seen that in the oxide sintered compacts of Examples 1 to 3, all of the crystal phases were composed of a single phase. Therefore, according to embodiment, when such an oxide sintered compact is used for a sputtering target so that the result of arcing evaluation may show, sputtering can be performed stably.

In addition, it can be seen that all of the oxide sintered bodies of Examples 1 to 3 had an average particle diameter of 15.0 µm or less. Therefore, according to embodiment, when grinding this oxide sintered compact, large crystal grains peel from the surface, and it can suppress that the surface becomes rough.

Moreover, it turns out that all of the sputtering targets of Examples 1-3 have the maximum height Ry of the surface roughness of an oxide sintered body 15.0 micrometers or less. Therefore, according to embodiment, when sputtering, it can suppress that a nodule generate|occur|produces on the target surface.

It turns out that the sputtering targets of Examples 1-3 have the maximum color difference ΔE ^* in the in-plane direction and the depth direction of 10 or less. Therefore, according to an embodiment, since there is no dispersion|variation in a crystal grain size or a composition, it is suitable as a sputtering target.

As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, Unless it deviates from the meaning, various changes are possible. For example, in embodiment, although the example in which the sputtering target was produced using a plate-shaped oxide sintered compact was demonstrated, the shape of an oxide sintered compact is not limited to a plate shape, A cylindrical shape etc. may be sufficient.

Other effects and modifications can be easily derived by those skilled in the art. For this reason, the broader aspect of this invention is not limited to the specific detail and typical embodiment which were described, demonstrating as mentioned above. Accordingly, various modifications can be made without departing from the spirit or scope of the overall inventive concept as defined by the appended claims and their equivalents.

Claims (11)

It is an oxide sintered body containing indium, gallium and zinc in an atomic ratio satisfying the following formulas (1) to (3),
Consists of single-phase crystalline phases,
The crystalline phase is an oxide sintered body in which diffraction peaks are observed in the following regions A to P in the chart obtained by X-ray diffraction measurement (CuKα ray).

A. 24.5° to 26.0°
B. 31.0° to 32.5°
C. 32.5° to 33.2°
D. 33.2° to 34.0°
E. 34.5° to 35.7°
F. 35.7° to 37.0°
G. 38.0° to 39.2°
H. 39.2° to 40.5°
I. 43.0° to 45.0°
J. 46.5° to 48.5°
K. 55.5° to 57.8°
L. 57.8° to 59.5°
M. 59.5° to 61.5°
N. 65.5° to 68.0°
O. 68.0° to 69.0°
P. 69.0° to 70.0° The method of claim 1,
The oxide sintered compact which contains indium, gallium, and zinc in the atomic ratio which satisfy|fills the following formula|equation (4) - (6).

3. The method of claim 1 or 2,
An oxide sintered body containing indium, gallium and zinc in an atomic ratio satisfying the following formulas (7) to (9).

3. The method of claim 1 or 2,
An oxide sintered body having an average particle diameter of the crystal phase of 15.0 μm or less. 3. The method of claim 1 or 2,
An oxide sintered body having a relative density of 97.0% or more. 3. The method of claim 1 or 2,
An oxide sintered body having a flexural strength of 40 MPa or more. 3. The method of claim 1 or 2,
An oxide sintered body having a specific resistance of 40 mΩ·cm or less. A sputtering target comprising the oxide sintered body according to claim 1 or 2 . 9. The method of claim 8,
The sputtering target whose maximum height Ry of surface roughness is 15.0 micrometers or less. 9. The method of claim 8,
A sputtering target having a color difference ΔE ^* of 10 or less. The manufacturing method of the oxide thin film which sputters and forms the sputtering target of Claim 8 into a film.

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