JP2013193945A - SINTERED BODY OF In-Ga-Zn-O-BASED OXIDE, METHOD FOR PRODUCING THE SAME, SPUTTERING TARGET AND OXIDE SEMICONDUCTOR FILM - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sintered body of an In-Ga-Zn-O-based oxide having improved film-forming speed and applicable to a sputtering target, and a method for producing the sintered body.SOLUTION: There is provided a sintered body of an In-Ga-Zn-O-based oxide containing In, Ga, Zn and O as constituent elements, having a content ratio of Ga to In of ≥1.0 and ≤1.6 in terms of atomic number ratio [Ga]/[In] and having a content ratio of Zn to In of ≥0.01 and ≤1.0 in terms of atomic number ratio [Zn]/[In]. Peak positions (2θ) of (009) plane, (101) plane and (104) plane of InGaZnOphase by X-ray diffraction with CuKα rays are deviated by ≥0.10° on a low angle side or high angle side compared with the corresponding peaks of an InGaZnOstandard peak list of ICDD database, and the sintered body has a specific resistance of ≤1.0×10Ωcm, and an average crystal particle diameter of ≥8.0 μm and ≤15.0 μm.

Description

  The present invention relates to an In—Ga—Zn—O-based oxide sintered body used as a raw material sputtering target and a method for producing the oxide semiconductor film by a film forming method such as a direct current sputtering method, In particular, an In—Ga—Zn—O-based oxide sintered body (sputtering target) in which the film forming speed (film forming rate) is improved during film formation, a manufacturing method thereof, and the sputtering target as a raw material. The present invention relates to the oxide semiconductor film used.

  The transparent conductive film has high conductivity and high transmittance in the visible light region, and is used for surface elements such as solar cells, liquid crystal display elements, organic electroluminescence and inorganic electroluminescence, and electrodes for touch panels. In addition, they are also used as various antifogging transparent heating elements such as automobile windows, heat ray reflective films for buildings, antistatic films, and refrigerated showcases.

The transparent conductive film includes a wide range of tin oxide (SnO ₂ ) containing antimony or fluorine as a dopant, zinc oxide (ZnO) containing aluminum or gallium as a dopant, indium oxide (In ₂ O ₃ ) containing tin as a dopant, and the like. It's being used. In particular, an indium oxide film containing tin as a dopant, that is, an In—Sn—O-based film is called an ITO (Indium tin oxide) film and is widely used because a low-resistance film can be easily obtained.

  A sputtering method is often used as a method for producing these transparent conductive films. The sputtering method is an effective method when film formation of a material having a low vapor pressure or precise film thickness control is required, and is widely used industrially because the operation is very simple.

  In the sputtering method, a target is used as a raw material. In general, a substrate is used as an anode under a gas pressure of about 10 Pa or less, the target is used as a cathode, and a glow discharge is generated between them to generate argon plasma. In this method, the argon cation is collided with the target of the cathode, and particles of the target component repelled by this are deposited on the substrate to form a film.

  Moreover, about manufacturing these oxide transparent conductive films using vapor deposition methods, such as ion plating, is also examined.

  However, an oxide transparent conductive film such as an ITO film or a ZnO-based film formed by a vapor deposition method such as a sputtering method or ion plating is likely to have oxygen defects, and a large number of carrier electrons are likely to be generated, resulting in an increase in electrical conductivity. Since it is a material, it is difficult to reduce the electrical conductivity. For this reason, it has not been used for an application such as a semiconductor film, in which the generation of carriers is required to be reduced to some extent by suppressing the generation of carriers.

  Under such circumstances, in various display devices such as a liquid crystal display device (LCD) and an electroluminescence display device (EL), a transistor having a switching role for driving the display device by applying a driving voltage to the display element is used. Among them, a thin film transistor (TFT) having a film thickness of 100 nm or less is particularly used among them, and as a material having high stability and mobility, an oxide has recently been substituted for an existing silicon-based semiconductor. Oxide semiconductor films using silicon have attracted attention.

  That is, as a material used for the TFT, a silicon-based semiconductor has been widely used for a long time, and a crystalline material and an amorphous material are selectively used depending on applications. For example, crystalline silicon has a high carrier mobility, and is therefore used for a high-frequency amplifying element or an integrated circuit element that requires high-speed operation. However, crystalline silicon has a difficulty in uniformity and the like in increasing the area, and there is a problem that additional costs such as a mask are generated in the uniformity. In addition, since a crystalline silicon-based thin film may be accompanied by a high-temperature process of 800 ° C. or higher when crystallization is performed, it is difficult to form a crystalline silicon thin film on a glass substrate or an organic substrate having no heat resistance. It can be formed only on a substrate having high heat resistance such as quartz. In addition to expensive substrates such as silicon wafers and quartz, there has been a problem that the energy and the number of processes required for production become very large.

  For these reasons, amorphous silicon is used in liquid crystal driving elements that require a large area.

  However, the amorphous silicon semiconductor has an advantage that it can be formed by a relatively low temperature process, but has a lower carrier mobility and a slower switching speed than crystalline silicon. When used as an element such as a liquid crystal, there is a problem that it becomes impossible to follow high-speed screen display.

As a method for solving these problems, in recent years, a method of driving an amorphous oxide semiconductor film containing In ₂ O ₃ , Ga ₂ O ₃ , and ZnO in a TFT has been studied. Since this material can be formed by a sputtering method that is widely used industrially and has excellent mass productivity, an In—Ga—Zn—O sputtering target has been studied.

  For example, an In—Ga—Zn—O sputtering target in which the specific resistance value as a characteristic is defined together with the composition has been proposed (Patent Document 1). However, when the In—Ga—Zn—O-based oxide target described in Patent Document 1 is used, the film formation rate is low even when sputtering film formation is performed under the condition of high power density, so that it is used industrially. There are difficulties in cases.

On the other hand, studies have been made on the effect of not generating a crystal phase such as Ga ₂ O ₃ having a high insulating property, which has a homologous crystal structure represented by InGaO ₃ (ZnO) as a main component (Patent Document 2).

  Furthermore, in order to make oxygen deficiency easy to occur, a method of providing a distribution of a structure having a higher In content than the surrounding and a structure having a higher Ga and Zn content than the surrounding has been proposed (Patent Document 3). .

However, a method for improving a film formation rate (film formation rate) by a sputtering method using an In—Ga—Zn—O-based oxide by controlling a crystal state of an InGaZnO ₄ [InGaO ₃ (ZnO)] crystal phase. In the past, no investigation has been made.

  Thus, there is a demand for a sputtering target in which the film formation rate at the time of film formation is improved, high productivity and good film characteristics are obtained, and fluctuations in film characteristics are suppressed. There is a need for a sintered body.

WO2009 / 084537 JP 2011-105563 A JP 2011-105995 A

  The present invention has been made to solve the above-described problems, and provides a sputtering target having an improved film formation rate (film formation rate), and an In—Ga—Zn—O-based oxidation provided for the sputtering target. An object of the present invention is to provide a sintered product and a method for manufacturing the same, and to provide an oxide semiconductor film using the sputtering target as a raw material.

  In order to solve the above problems, the present inventors conducted extensive research and found that the film formation rate (film formation rate) during film formation was In—Ga—Zn—O-based oxide sintered body (ie, sputtering). The technical discovery that it is closely related to the crystal structure of the target) and its crystal particle size. Furthermore, the crystal structure of the In—Ga—Zn—O-based oxide sintered body that improves the film formation rate (film formation rate) and the crystal particle diameter thereof are determined by the pre-molding and the subsequent steps in the step of obtaining the compact before firing. It has been found that this can be achieved by controlling the crystal orientation in the final molding and further setting the firing temperature of the final molded body to 1350 ° C. or higher and 1600 ° C. or lower. The present invention has been completed through such technical discovery and examination.

That is, the invention according to claim 1
In the In—Ga—Zn—O-based oxide sintered body,
Indium (In), gallium (Ga), zinc (Zn), and oxygen (O) are constituent elements, and the content of gallium with respect to indium is 1.0 or more and 1.6 or less in atomic ratio [Ga] / [In]. And an In—Ga—Zn—O-based oxide sintered body having an atomic ratio [Zn] / [In] of 0.01 to 1.0 in terms of atomic ratio, and a CuKα ray The peak positions (2θ) of the (009) plane, (101) plane, and (104) plane in the InGaZnO ₄ phase by X-ray diffraction using X-ray diffraction are InGaZnO ₄ standard peak lists in the ICDD (International Center for Diffraction Date) database (reference code) : 00-038-1104) is shifted to the low angle side or the high angle side by 0.10 ° or more and the specific resistance value is 1.0 × 10 ⁻¹ Ω · cm or less. The average grain size of the crystal is 8.0 μm or more and 15.0 μm or less.

  In the In—Ga—Zn—O-based oxide sintered body according to the present invention, the constituent elements are substantially composed of indium (In), gallium (Ga), zinc (Zn), and oxygen (O). What is necessary is not to limit mixing of inevitable impurities.

Next, the invention according to claim 2
In the In-Ga-Zn-O-based oxide sintered body according to claim 1,
The deviation from the same peak of the InGaZnO ₄ standard peak list in the ICDD database is 0.10 ° or more and 0.30 ° or less,
The invention according to claim 3
In the In-Ga-Zn-O-based oxide sintered body according to claim 1 or 2,
The average grain size of the crystal is 10.0 μm or more.

The invention according to claim 4
In the method for producing the In-Ga-Zn-O-based oxide sintered body according to any one of claims 1 to 3,
In ₂ O ₃ powder, ZnO powder and Ga ₂ O ₃ powder are mixed with pure water, an organic binder, a dispersant to prepare a slurry, and the slurry is dried and granulated to obtain a granulated powder;
The obtained granulated powder is preformed under a pressure condition of 0.03 MPa or higher using a mold press, and then subjected to a main molding by a hydrostatic pressure method under a pressure condition of 98 MPa or higher to obtain a final molded body. Process,
A step of firing the obtained final molded body at 1350 ° C. to 1600 ° C. to obtain a sintered body,
It is characterized by comprising each step of
The invention according to claim 5
In the manufacturing method of the In-Ga-Zn-O-based oxide sintered body according to claim 4,
The final molded body is fired under an oxygen condition in a firing furnace.

Next, the invention according to claim 6 is:
In sputtering target,
It is obtained by processing the In-Ga-Zn-O-based oxide sintered body according to any one of claims 1 to 3,
The invention according to claim 7
In an oxide semiconductor film formed by a sputtering method,
The sputtering target according to claim 6 is used as a raw material, and indium, gallium, zinc and oxygen are constituent elements, and the content of gallium with respect to indium is 1.0 or more and 1.6 in terms of atomic ratio [Ga] / [In]. Hereinafter, the content of zinc with respect to indium is 0.01 to 1.0 in terms of atomic ratio [Zn] / [In].

The In—Ga—Zn—O-based oxide sintered body according to the present invention is:
The peak positions (2θ) of the (009) plane, (101) plane and (104) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays are the InGaZnO ₄ standard peak list in the ICDD (International Center for Diffraction Date) database ( Reference code: 00-038-1104) has a crystal structure shifted by 0.10 ° or more on the low angle side or high angle side as compared with the same peak, and the average crystal grain size is 8.0 μm or more and 15. 0 μm or less.

  When a sputtering target obtained by processing the In—Ga—Zn—O-based oxide sintered body having the crystal structure and the crystal particle diameter described above is applied to the sputtering method, the film formation speed during film formation Since the (deposition rate) is improved and becomes faster, it is possible to perform an efficient film formation process, and it is possible to form a favorable oxide semiconductor film because fluctuations in film characteristics are also suppressed. Yes.

  Hereinafter, embodiments of the present invention will be specifically described.

  First, the In—Ga—Zn—O-based oxide sintered body according to the present invention has been completed through technical discovery and examination by the present inventors as described above.

  That is, the film formation rate (film formation rate) during sputtering film formation is closely related to the crystal structure and crystal particle diameter of the In—Ga—Zn—O-based oxide sintered body constituting the sputtering target. The present inventors have made a technical discovery. Then, in order to obtain an In—Ga—Zn—O-based oxide sintered body having a crystal structure and a crystal particle diameter capable of increasing the film formation speed (film formation rate) during film formation, a molded body before firing is obtained. In the process, after preforming by uniaxial mold press molding, the crystal orientation is controlled in the process of obtaining the final molded body by performing pressure molding, and further the temperature for firing the final molded body is 1350 ° C or higher and 1600 ° C or lower It has been found that this can be achieved by promoting the grain growth of crystal grains.

(1) In-Ga-Zn-O-based oxide sintered body according to the present invention The In-Ga-Zn-O-based oxide sintered body according to the present invention is applied as a sputtering target, and includes indium (In), An oxide sintered body containing gallium (Ga), zinc (Zn), and oxygen (O) as constituent elements. In the oxide sintered body, the gallium content with respect to indium is 1.0 to 1.6 in terms of atomic ratio [Ga] / In, and the zinc content with respect to indium is atomic ratio [Zn] / In. [In] is 0.01 or more and 1.0 or less. The reason why the contents of indium (In), gallium (Ga) and zinc (Zn) in the oxide sintered body are defined in the above range is that the resistance value of the oxide sintered body obtained when the oxide sintered body is out of this range. This is because not only will the productivity increase during the film formation, but also the characteristics of the resulting film may be deteriorated. In addition, when the content of gallium and zinc is larger than the above range of the atomic number ratio, the crystallinity is deteriorated, grain growth is inhibited, and it is difficult to obtain the particle size required for the oxide sintered body. This is also not preferable.

Further, the In—Ga—Zn—O-based oxide sintered body according to the present invention has peaks in the (009) plane, (101) plane, and (104) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays. The position (2θ) is 0.10 ° or more on the low angle side or high angle side compared to the same peak in the InGaZnO ₄ standard peak list (reference code: 00-038-1104) in the ICDD (International Center for Diffraction Date) database. It is necessary that the average particle size of the crystals constituting the structure of the oxide sintered body is 8.0 μm or more and 15.0 μm or less. When these characteristics are satisfied at the same time, the film formation rate (film formation rate) during film formation can be improved by 10% or more compared to the case where these characteristics are not satisfied.

(2) Manufacturing method of In-Ga-Zn-O-based oxide sintered body according to the present invention Next, a manufacturing process of the In-Ga-Zn-O-based oxide sintered body according to the present invention will be described.

[Granulation process]
Constituent elements such as In ₂ O ₃ (tin oxide) powder, Ga ₂ O ₃ (gallium oxide) powder, and ZnO (zinc oxide) powder have a raw material powder concentration of 50 to 80 wt%, preferably 60 wt%. In addition, it is mixed with pure water, an organic binder, and a dispersant, and wet pulverized until the average particle size becomes 0.5 μm or less. By reducing the average particle size of the mixed powder to 0.5 μm or less, aggregation of ZnO (zinc oxide) powder and In ₂ O ₃ (tin oxide) powder can be reliably removed.

  After wet grinding, a slurry is prepared by mixing and stirring for 10 minutes or more, and the resulting slurry is dried and granulated to obtain a granulated powder.

[Molding process]
Next, the obtained granulated powder is preformed under a pressing condition of 0.03 MPa (0.3 kgf / cm ² ) or more using a uniaxial die press molding machine, and then the pressing condition of 98 MPa or more. The final molding is obtained by performing the main molding. Here, when performing the main forming, it is desirable to use a cold isostatic press (CIP) that can obtain a high pressure.

When the pressure at the time of the above preforming is less than 0.03 MPa, the stress in a specific direction applied to the molded body by the uniaxial die press molding machine becomes insufficient, and the desired orientation control is difficult when the sintered body is formed. It becomes. The shift of the peak position (2θ) of the (009) plane, (101) plane, and (104) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays is the InGaZnO ₄ standard peak list (reference code: 00-038- When the angle is less than 0.10 ° compared to the same peak of 1104), the effect of improving the deposition rate (deposition rate) cannot be obtained. Note that if the shift of the peak position (2θ) is too large, the crystal structure is excessively distorted, which may adversely affect the improvement effect of the film formation rate (film formation rate) due to the decrease in carrier mobility. Therefore, the deviation of the peak position (2θ) is preferably 0.30 ° or less.

  Moreover, when the pressure at the time of this shaping | molding is less than 98 Mpa, it will become difficult to remove the void | hole which exists between the particle | grains of raw material powder, and will bring about the density fall of a sintered compact. In addition, since the strength of the compact is reduced, stable production becomes difficult.

  The upper limit of pressure in both preforming and main molding is not particularly specified, but the higher the pressure during the molding, the better the higher the pressure after firing, and the higher the pressure in the high pressure range. There is no difference in the properties of the body.

[Sintering process]
The In-Ga-Zn-O-based oxide sintered body according to the present invention is obtained by firing the final molded body obtained in the molding step at normal pressure.

  The firing temperature is 1350 ° C to 1600 ° C, preferably 1400 ° C to 1500 ° C. When the sintering temperature is less than 1350 ° C., even if an oxide sintered body having a certain density is obtained, the required grain growth does not occur, so that an improvement effect of improving the film formation rate (film formation rate) is obtained. I can't. In addition, when the sintering temperature exceeds 1600 ° C., ZnO (zinc oxide) and the like are volatilized and easily deviate from a predetermined composition particularly on the surface of the sintered body. In addition, for film formation such as sputtering, the larger the crystal grain size in the sintered body (ie, the target), the higher the film formation rate (film formation rate) can be expected, but the sintering temperature exceeded 1600 ° C. In this case, the crystal grain size exceeds 15 μm, and the strength of the sintered body is significantly reduced. And since the generation | occurrence | production of a crack is caused at the time of sintered compact manufacture by the remarkable fall of a sintered compact strength, and a yield is deteriorated, it is unpreferable.

  Further, during the firing process, the atmosphere in the firing furnace is atmospheric pressure air, preferably oxygen atmosphere. By introducing and activating oxygen gas, the growth of crystal grains in the sintered body is promoted, and high productivity when using an oxide target can be realized. However, even in an oxygen atmosphere, it is difficult to say that sufficient grain growth occurs if the firing temperature is lower than the above-described 1350 ° C., and an effective grain size that improves the deposition rate (deposition rate) cannot be obtained.

  Then, the obtained In—Ga—Zn—O-based oxide sintered body is processed into a predetermined shape and size as necessary. In addition, when used for sputtering, it is bonded to a predetermined backing plate and applied as a sputtering target.

  Examples of the present invention will be specifically described below with reference to comparative examples. However, these examples do not limit the present invention.

[sample test]
(1) The produced sintered body was quantitatively analyzed by ICP emission spectroscopic analysis (manufactured by Seiko Instruments Inc., SPS4000).

(2) The specific resistance value of the produced sintered body was measured by a four-probe method using a resistivity meter Loresta EP (Dia Instruments MCP-T360 type).

(3) The orientation of the produced sintered body is measured by X-ray diffraction measurement (manufactured by PANalytical, X′Pert Pro MPD), and the (009) plane in the InGaZnO ₄ crystal phase constituting the sintered body, (101) How many times the peak position (2θ) of the plane and (104) plane deviates from that of the InGaZnO ₄ standard peak list (reference code: 00-038-1104) in the ICDD (International Center for Diffraction Date) database Evaluated.

  The peak positions in the ICDD database are (2θ) of 30.84 ° on the (009) plane, 31.51 ° on the (101) plane, and 34.28 ° on the (104) plane, respectively.

(4) The crystal grain size of the produced sintered body was measured by measuring the average crystal grain size by observing, by SEM, a sample in which the cut surface was mirror-polished and then thermally corroded to precipitate crystal grain boundaries.

(5) The film formation rate (film formation rate) during film formation was calculated by measuring the film thickness of the film formed and dividing by the film formation time. At this time, the film thickness was measured by the following procedure. Before forming the film, apply oil-based ink to a part of the substrate in advance, wipe the oil-based ink with ethanol after film formation to form a part without film, and make the step between the part with film and the part without film It measured and calculated | required with the measuring device (Alpha-Step IQ by KLA Tencor).

[Example 1]
In ₂ O ₃ powder, Ga ₂ O ₃ powder, and ZnO powder each having an average particle diameter of 1 μm or less are used as raw material powder, and the content of gallium with respect to indium is 1.0 at an atomic ratio [Ga] / [In]. The zinc content is adjusted to 1.0 at an atomic ratio [Zn] / [In] and mixed with pure water, an organic binder, and a dispersant so that the raw material powder concentration is 60 wt%. At the same time, a slurry was prepared in a mixing tank.

Next, using a bead mill apparatus (manufactured by Ashizawa Finetech Co., Ltd., LMZ type) charged with hard ZrO ₂ balls, pulverization and mixing were performed until the average particle size of the raw material powder became 0.5 μm or less. A laser diffraction particle size distribution measuring device (SALD-2200, manufactured by Shimadzu Corporation) was used to measure the average particle size of the raw material powder.

  Next, the obtained slurry was sprayed and dried with a spray dryer (Okawara Kako Co., Ltd., ODL-20 type) to obtain granulated powder.

The obtained granulated powder was cold-pressed (CP: Cold Press) by applying a pressure of 0.06 MPa (0.6 kgf / cm ² ) with a 10MN powder molding machine (manufactured by Kotaki Seiki Co., Ltd., KPS1000-N0769 type). Then, the film was subjected to main molding by applying a pressure of 294 MPa (3 ton / cm ² ) by a cold isostatic press (CIP) to obtain a final molded body having a diameter of about 200 mm.

  Then, in the atmospheric pressure sintering furnace, the final compact was fired for 20 hours at a firing temperature of 1400 ° C., and the In—Ga—Zn—O-based oxide sintered body according to Example 1 was obtained. Obtained.

In the composition of the In—Ga—Zn—O-based oxide sintered body according to Example 1, the gallium content is 1.0 in atomic ratio [Ga] / [In], and the zinc content is atomic ratio. [Zn] / [In] was 1.0, and the specific resistance value was 2.1 × 10 ⁻² Ω · cm.

Further, when the peak positions (2θ) of the (009) plane, the (101) plane, and the (104) plane in the InGaZnO ₄ phase were confirmed by X-ray diffraction using CuKα rays, 2θ was 30.66 °, 31. 27 ° and 34.04 °.

  Furthermore, the average crystal grain size of the In—Ga—Zn—O-based oxide sintered body according to Example 1 was measured and found to be 8.2 μm.

  Next, the In—Ga—Zn—O-based oxide sintered body according to Example 1 obtained was processed to have a diameter of 152.4 mm (6 inches) and a thickness of 5 mm, and a sputtering target was formed. Obtained.

Then, after the obtained sputtering target was mounted on a sputtering apparatus (SPF-530K, manufactured by Tokki), a film was formed by a sputtering method for 10 minutes at an input power of 1.6 W / cm ² , and the film formation speed was determined from the film thickness. (Deposition rate) was confirmed.

The sputtering conditions were such that the distance between the substrate and the target was 46 mm, the ultimate vacuum was 2.0 × 10 ⁻⁴ Pa or less, and the gas pressure was 0.6 Pa.

  As a result, the film formation speed of Example 1 was “79.6 nm / min.”, “Film formation speed: 71.0 nm / min.” Of Comparative Example 1 described below, and “Film formation speed: Comparative Example 2”. 66.3 nm / min. ”.

Thus, the specific resistance value is 2.1 × 10 ⁻² Ω · cm (that is, 1.0 × 10 ⁻¹ Ω · cm or less) and the crystal grain size is 8.2 μm (that is, 8.0 μm or more). Condition) and the peak position (2θ) of the (009) plane, (101) plane, and (104) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays is 0.1 ° or more, respectively. An In—Ga—Zn—O-based oxide sintered body (sputtering target) according to Example 1 that satisfies certain conditions is an oxide sintered body (sputtering target) according to Comparative Example 1 and Comparative Example 2 described below. It was confirmed that the film formation rate (film formation rate) was 10% or more faster than that.

[Comparative Example 1]
A granulated powder was obtained in the same manner as in Example 1, and the resulting granulated powder was subjected to cold isostatic pressing (10) by using a 10MN powder molding machine (Kotaki Seiki Co., Ltd., KPS1000-N0769). CIP: Cold isostatic press) was applied at a pressure of 294 MPa (3 ton / cm ² ) to perform the main molding, and after obtaining a molded body having a diameter of about 200 mm, the same conditions as in Example 1, ie, atmospheric pressure sintering A compact was fired for 20 hours in a normal pressure atmosphere at a firing temperature of 1400 ° C. in an atmospheric pressure atmosphere to obtain an In—Ga—Zn—O-based oxide sintered body according to Comparative Example 1.

As in Example 1, the composition of the In—Ga—Zn—O-based oxide sintered body according to Comparative Example 1 is 1.0 in terms of the atomic ratio [Ga] / [In], and the zinc content is as follows. The content was 1.0 in terms of the atomic ratio [Zn] / [In], and the specific resistance value was 2.4 × 10 ⁻² Ω · cm, different from Example 1.

Further, when the peak positions (2θ) of the (009) plane, the (101) plane, and the (104) plane in the InGaZnO ₄ phase were confirmed by X-ray diffraction using CuKα rays, 2θ was 30.79 °, 31. 48 ° and 34.25 °.

  Furthermore, when the average crystal grain size of the In—Ga—Zn—O-based oxide sintered body according to Comparative Example 1 was measured, it was 8.3 μm.

  And when the film-forming speed | rate of the In-Ga-Zn-O type oxide sintered compact (target) which concerns on the comparative example 1 on the conditions similar to Example 1 was confirmed, as above-mentioned, "film-forming speed | rate: 71 0.0 nm / min. ”.

Thus, the specific resistance value is 2.4 × 10 ⁻² Ω · cm (that is, 1.0 × 10 ⁻¹ Ω · cm or less) and the crystal grain size is 8.3 μm (that is, 8.0 μm or more). Condition), but the deviation of the peak position (2θ) of the (009) plane, (101) plane, and (104) plane in the InGaZnO ₄ phase by the X-ray diffraction is 0.1 ° or more. The In—Ga—Zn—O-based oxide sintered body (sputtering target) according to Comparative Example 1 that is not satisfied is inferior in film formation rate (film formation rate) as compared to Example 1 described above (Example 1). The film formation rate was 79.6 nm / min. The film formation rate of Comparative Example 1 was 71.0 nm / min.).

[Comparative Example 2]
A granulated powder was obtained in the same manner as in Example 1, and the obtained granulated powder was subjected to a pressure of 0.06 MPa (0.6 kgf / cm ² ) with a 10MN powder molding machine (manufactured by Kotaki Seiki Co., Ltd., KPS1000-N0769 type). And then pre-molding with a cold press (CP: Cold Press), followed by main molding with a cold isostatic press (CIP: Cold Isostatic Press) under a pressure of 294 MPa (3 ton / cm ² ). The final molded product was obtained.

  Then, the final molded body was fired for 20 hours at a firing temperature of 1300 ° C. (fire temperature: 1400 ° C. in Example 1) in an atmospheric pressure atmosphere in an atmospheric pressure sintering furnace. A —Zn—O-based oxide sintered body was obtained.

As in Example 1, the composition of the In—Ga—Zn—O-based oxide sintered body according to Comparative Example 2 has a gallium content of 1.0 at an atomic ratio [Ga] / [In] of zinc, The content was 1.0 in terms of the atomic ratio [Zn] / [In], and the specific resistance value was 3.8 × 10 ⁻² Ω · cm, unlike Example 1.

Further, when the peak positions (2θ) of the (009) plane, (101) plane, and (104) plane in the InGaZnO ₄ phase were confirmed by X-ray diffraction using CuKα rays, 2θ was 30.71 ° and 31.31 °, respectively. 31 ° and 34.06 °.

  Furthermore, the average crystal grain size of the In—Ga—Zn—O-based oxide sintered body according to Comparative Example 2 was measured and found to be 3.9 μm.

  And when the film-forming speed | rate of the In-Ga-Zn-O type oxide sintered compact (target) which concerns on the comparative example 2 on the conditions similar to Example 1 was confirmed, as above-mentioned, "film-forming speed | rate: 66 .3 nm / min. "

Thus, the specific resistance value is 3.8 × 10 ⁻² Ω · cm (that is, the condition of 1.0 × 10 ⁻¹ Ω · cm or less), the (009) plane in the InGaZnO ₄ phase by the X-ray diffraction, The deviation of the peak position (2θ) of the (101) plane and the (104) plane is 0.1 ° or more, but the crystal grain size is 3.9 μm and does not satisfy the condition of 8.0 μm or more. The In—Ga—Zn—O-based oxide sintered body (sputtering target) according to Comparative Example 2 is inferior in film formation rate (film formation rate) as compared to Example 1 described above (the composition of Example 1). It was confirmed that the film speed was 79.6 nm / min. The film formation speed of Comparative Example 2 was 66.3 nm / min.).

[Example 2 and Comparative Example 3]
In-Ga-Zn-O-based oxide firing was performed under the same conditions as in Example 1 except that the pressure at the time of preforming with CP was set to 0.03 MPa (Example 2) and 0.01 MPa (Comparative Example 3). A ligation was produced.

  The composition of the obtained In—Ga—Zn—O-based oxide sintered bodies according to Example 2 and Comparative Example 3 was the same as in Example 1 in that the gallium content was atomic ratio [Ga] / [In]. The zinc content was 1.0 at an atomic ratio [Zn] / [In].

Moreover, the specific resistance value of the In-Ga-Zn-O-based oxide sintered body according to Example 2 and Comparative Example 3 obtained, (009) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays, When the deviation of the peak position (2θ) of the (101) plane and the (104) plane and the average crystal grain size were measured in the same manner as in Example 1, the results shown in Table 2 below were obtained.

As a result, in the In—Ga—Zn—O-based oxide sintered body according to Example 2, the specific resistance value (1.0 × 10 ⁻¹ Ω · cm or less), the crystal grain size (8.0 μm) were obtained. The deviation of the peak position (2θ) of the (009) plane, (101) plane and (104) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays is 0.1 ° or more, respectively. While all of the certain conditions were satisfied, in Comparative Example 3, the deviation of the X-ray diffraction peak position was small because the pressure of the CP preforming value was insufficient.

  Next, the obtained In—Ga—Zn—O-based oxide sintered body according to Example 2 and Comparative Example 3 was processed under the same conditions as in Example 1 to obtain a sputtering target. The film formation rate (deposition rate) was confirmed from the film thickness under the same conditions as in Example 1, and the film formation rate (film formation rate) was confirmed. Example 2 was “78.4 nm / min.” And Comparative Example 3 was “70”. .3 nm / min. "

Thus, in the condition of the specific resistance value (1.0 × 10 ⁻¹ Ω · cm or less), the condition of the crystal grain size (8.0 μm or more), and the InGaZnO ₄ phase by X-ray diffraction using CuKα rays ( The In—Ga—Zn—O system according to Example 2 that satisfies all of the conditions that the deviation of the peak position (2θ) of the (009) plane, the (101) plane, and the (104) plane is 0.1 ° or more, respectively. The oxide sintered body (sputtering target) has a film formation rate (deposition rate) of 10% as compared with the oxide sintered bodies (sputtering target) according to Comparative Examples 1 to 3 that do not satisfy all these conditions. It was confirmed that it was faster.

[Example 3 and Comparative Example 4]
In—Ga— was performed in the same manner as in Example 1 except that the atmosphere in the firing furnace was O ₂ and the firing temperature was 1400 ° C. (Example 3) and 1300 ° C. (Comparative Example 4), respectively. A Zn—O-based oxide sintered body was produced.

  As for the composition of the obtained In—Ga—Zn—O-based oxide sintered body according to Example 3 and Comparative Example 4, the gallium content is the atomic ratio [Ga] / [In]. The zinc content was 1.0 at an atomic ratio [Zn] / [In].

Moreover, the specific resistance value of the In-Ga-Zn-O-based oxide sintered body according to Example 3 and Comparative Example 4 obtained, (009) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays, When the deviation of the peak position (2θ) of the (101) plane and the (104) plane and the average crystal grain size were measured in the same manner as in Example 1, the results shown in Table 2 below were obtained.

As a result, in the In—Ga—Zn—O-based oxide sintered body according to Example 3, the specific resistance value (1.0 × 10 ⁻¹ Ω · cm or less), the crystal grain size (8.0 μm) were obtained. The deviation of the peak position (2θ) of the (009) plane, (101) plane and (104) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays is 0.1 ° or more, respectively. While all of the certain conditions were satisfied, in Comparative Example 4, the firing temperature (1300 ° C.) was too low, so that sufficient grain growth did not occur even when firing in an oxygen atmosphere.

  Next, the obtained In—Ga—Zn—O-based oxide sintered body according to Example 3 and Comparative Example 4 was processed under the same conditions as in Example 1 to obtain a sputtering target. The film formation rate (deposition rate) was confirmed from the film thickness under the same conditions as in Example 1, and the film formation rate (film formation rate) was confirmed. Example 3 was “84.5 nm / min.” And Comparative Example 4 was “70”. .8 nm / min ".

Thus, in the condition of the specific resistance value (1.0 × 10 ⁻¹ Ω · cm or less), the condition of the crystal grain size (8.0 μm or more), and the InGaZnO ₄ phase by X-ray diffraction using CuKα rays ( The In—Ga—Zn—O system according to Example 3 that satisfies all of the conditions that the deviation of the peak position (2θ) of the (009) plane, (101) plane, and (104) plane is 0.1 ° or more, respectively. The oxide sintered body (sputtering target) has a film formation rate (film formation rate) of 10% compared to the oxide sintered body (sputtering target) according to Comparative Examples 1 to 4 that does not satisfy all these conditions. It was confirmed that it was faster.

[Comparative Example 5]
An In—Ga—Zn—O-based oxide sintered body was produced in the same manner as in Example 1 except that the firing temperature was 1650 ° C. during firing of the molded body.

  The composition of the obtained In—Ga—Zn—O-based oxide sintered body according to Comparative Example 5 has a gallium content of 1.1 in atomic ratio [Ga] / [In], and a zinc content of The atomic ratio [Zn] / [In] is 0.7, and since the sintering temperature (1650 ° C.) is too high, the volatilization has occurred or the composition has shifted compared to the input composition. It was confirmed that the conditions were not industrially useful.

In addition, the specific resistance value of the obtained In—Ga—Zn—O-based oxide sintered body according to Comparative Example 5, (009) plane, (101) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα ray Further, when the deviation of the peak position (2θ) on the (104) plane and the average crystal grain size value were measured by the same method as in Example 1, the results shown in Table 2 below were obtained.

  Next, the obtained In—Ga—Zn—O-based oxide sintered body according to Comparative Example 5 was processed under the same conditions as in Example 1 to obtain a sputtering target, and the same conditions as in Example 1 were obtained. The film formation rate (deposition rate) was confirmed from the film thickness by sputtering, and the film formation rate (deposition rate) of Comparative Example 5 was “88.4 nm / min.”. It was.

  In Comparative Example 5, although the effect of improving the film formation rate (deposition rate) was confirmed from the effects of grain growth (15.2 μm) and the XRD peak position, the obtained film was a sintered body of Comparative Example 5 Similarly, the obtained sintered body was deviated from the intended composition, and the strength of the sintered body was reduced due to excessive grain growth.

  From these results, it was confirmed that the conditions of Comparative Example 5 were not industrially useful.

[Example 4 and Comparative Examples 6 to 8]
The gallium content is 1.5 (Example 4), 0.9 (Comparative Example 6), and 1.7 (Comparative Example 7) in terms of atomic ratio [Ga] / [In], and the zinc content Is the same as Example 1 except that the atomic ratio [Zn] / [In] is 1.2 (Comparative Example 8). In-Ga-Zn-O according to Example 4 and Comparative Examples 6-8 A system oxide sintered body was produced.

  The compositions of the obtained In—Ga—Zn—O-based oxide sintered bodies according to Example 4 and Comparative Examples 6 to 8 matched the input composition as shown in Table 2.

In addition, specific resistance values of the obtained In-Ga-Zn-O-based oxide sintered bodies according to Example 4 and Comparative Examples 6 to 8, in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays (009) When the surface, (101) plane, (104) plane peak position (2θ) deviation, and average crystal grain size were measured in the same manner as in Example 1, the results shown in Table 2 were obtained.

As a result, in the In—Ga—Zn—O-based oxide sintered body according to Example 4, the specific resistance value (1.0 × 10 ⁻¹ Ω · cm or less), the crystal grain size (8.0 μm) were obtained. The deviation of the peak position (2θ) of the (009) plane, (101) plane and (104) plane in the InGaZnO ₄ phase by X-ray diffraction using CuKα rays is 0.1 ° or more, respectively. While all of the certain conditions are satisfied, in Comparative Example 6, the specific resistance value (1.2 × 10 ⁻¹ Ω · cm) is 1.0 × 10 ⁻¹ Ω · cm due to the small amount of Ga. It was over. In Comparative Example 7 and Comparative Example 8, sintering was not only caused by high specific resistance (1.3 × 10 ⁻¹ Ω · cm) but also due to a decrease in crystallinity because of excessive Ga or Zn, respectively. The particle size in the body was smaller than 8.0 μm (Comparative Example 7 was 7.6 μm, Comparative Example 8 was 7.8 μm).

  Next, the obtained In—Ga—Zn—O-based oxide sintered body according to Example 4 and Comparative Examples 6 to 8 was processed under the same conditions as in Example 1 to obtain a sputtering target, and Film formation by sputtering was performed under the same conditions as in Example 1, and the film formation rate (deposition rate) was confirmed from the film thickness. As a result, Example 4 was “78.3 nm / min.” And Comparative Example 6 was “70.9 nm / min.”, Comparative Example 7 was “69.9 nm / min.”, And Comparative Example 8 was “70.4 nm / min.”.

Thus, in the condition of the specific resistance value (1.0 × 10 ⁻¹ Ω · cm or less), the condition of the crystal grain size (8.0 μm or more), and the InGaZnO ₄ phase by X-ray diffraction using CuKα rays ( The In—Ga—Zn—O system according to Example 4 that satisfies all of the conditions that the deviation of the peak position (2θ) of the (009) plane, the (101) plane, and the (104) plane is 0.1 ° or more, respectively. The oxide sintered body (sputtering target) has a film formation rate (deposition rate) of 10% as compared with the oxide sintered bodies (sputtering target) according to Comparative Examples 1 to 8 that do not satisfy all these conditions. It was confirmed that it was faster.

  Since a sputtering target obtained by processing the In—Ga—Zn—O-based oxide sintered body according to the present invention has a high film formation speed (film formation rate) and is fast, for example, a thin film transistor (TFT) is formed by sputtering. It has industrial applicability applied to sputtering targets when formed as a film.

Claims (7)

Indium (In), gallium (Ga), zinc (Zn), and oxygen (O) are constituent elements, and the content of gallium with respect to indium is 1.0 or more and 1.6 or less in atomic ratio [Ga] / [In]. And an In—Ga—Zn—O-based oxide sintered body having an atomic ratio [Zn] / [In] of 0.01 to 1.0 in terms of atomic ratio, and a CuKα ray The peak positions (2θ) of the (009) plane, (101) plane, and (104) plane in the InGaZnO ₄ phase by X-ray diffraction using X-ray diffraction are InGaZnO ₄ standard peak lists in the ICDD (International Center for Diffraction Date) database (reference code) : 00-038-1104) is shifted to the low angle side or the high angle side by 0.10 ° or more and the specific resistance value is 1.0 × 10 ⁻¹ Ω · cm or less. An In—Ga—Zn—O-based oxide sintered body having an average grain size of 8.0 to 15.0 μm. 2. The In—Ga—Zn—O-based oxide firing according to claim 1, wherein a deviation from the same peak of the InGaZnO ₄ standard peak list in the ICDD database is 0.10 ° or more and 0.30 ° or less. Union.   3. The In—Ga—Zn—O-based oxide sintered body according to claim 1, wherein an average grain size of the crystal is 10.0 μm or more. In the method for producing the In-Ga-Zn-O-based oxide sintered body according to any one of claims 1 to 3,
In ₂ O ₃ powder, ZnO powder and Ga ₂ O ₃ powder are mixed with pure water, an organic binder, a dispersant to prepare a slurry, and the slurry is dried and granulated to obtain a granulated powder;
The obtained granulated powder is preformed under a pressure condition of 0.03 MPa or higher using a mold press, and then subjected to a main molding by a hydrostatic pressure method under a pressure condition of 98 MPa or higher to obtain a final molded body. Process,
A step of firing the obtained final molded body at 1350 ° C. to 1600 ° C. to obtain a sintered body,
The manufacturing method of the In-Ga-Zn-O type oxide sintered compact characterized by comprising each process of these.   The method for producing an In—Ga—Zn—O-based oxide sintered body according to claim 4, wherein the final molded body is fired under an oxygen condition in a firing furnace.   A sputtering target obtained by processing the In—Ga—Zn—O-based oxide sintered body according to claim 1. In an oxide semiconductor film formed by a sputtering method,
The sputtering target according to claim 6 is used as a raw material, and indium, gallium, zinc and oxygen are constituent elements, and the content of gallium with respect to indium is 1.0 or more and 1.6 in terms of atomic ratio [Ga] / [In]. An oxide semiconductor film having a zinc content with respect to indium of 0.01 to 1.0 in terms of atomic ratio [Zn] / [In].