JP2012144410A - Oxide sintered compact, and sputtering target - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxide sintered compact which is used appropriately for producing an oxide semiconductor film for a display; and a sputtering target having both high conductivity and high relative density.SOLUTION: The oxide sintered compact is obtained by mixing and sintering indium oxide powder, gallium oxide powder, zinc oxide powder, and the powder of at least one kind of metal (metal M) selected from the group consisting of Si, Ni and Hf. When the oxide sintered compact is subjected to X-ray diffraction, (1) InGaZnOis made a main phase, and at least part of the metal M is solid-dissolved in the InGaZnO, and (2) a ZnMOphase and an MOphase (x and y are an optional integer) are not detected.

Description

  The present invention relates to an oxide sintered body and a sputtering target used when a thin film transistor (TFT) oxide semiconductor thin film used in a display device such as a liquid crystal display or an organic EL display is formed by a sputtering method.

  Amorphous (amorphous) oxide semiconductors used for TFTs have higher carrier mobility than general-purpose amorphous silicon (a-Si), a large optical band gap, and can be formed at low temperatures. It is expected to be applied to next-generation displays that require high resolution and high-speed driving, and resin substrates with low heat resistance. In forming the oxide semiconductor (film), a sputtering method is preferably used in which a sputtering target made of the same material as the film is sputtered. In-plane uniformity of component composition and film thickness in the film surface direction (in the film surface) is smaller in the thin film formed by sputtering compared to thin films formed by ion plating, vacuum evaporation, and electron beam evaporation. This is because it has the advantage that a thin film having the same composition as the sputtering target can be formed. The sputtering target is usually formed by mixing and sintering oxide powder and machining.

  The most advanced composition of oxide semiconductors used in display devices is In-containing In—Ga—Zn—O (IGZO) amorphous oxide semiconductors, which are used for next-generation display devices. In order to form a high-quality and stable thin film and improve the reliability of TFT characteristics, high-quality IGZO-based oxide semiconductors have been proposed (for example, Patent Documents 1 to 3).

JP 2008-214697 A JP 2008-163441 A JP 2008-163442 A

  It is desired that a sputtering target used for manufacturing an oxide semiconductor film for a display device and an oxide sintered body that is a material thereof have excellent conductivity and a high relative density. In consideration of mass production and manufacturing cost on a large substrate, it is desired to provide a sputtering target that can be stably manufactured not by the high frequency (RF) sputtering method but by the direct current (DC) sputtering method that facilitates high-speed film formation. It is rare.

  The present invention has been made in view of the above circumstances, and an object thereof is an oxide sintered body and a sputtering target that are suitably used for manufacturing an oxide semiconductor film for a display device, and have high conductivity and relative density. The object is to provide an oxide sintered body and a sputtering target having both of the above.

The oxide sintered body of the present invention that can solve the above-mentioned problems is at least one metal (M metal) selected from the group consisting of indium oxide, gallium oxide, zinc oxide, Si, Ni, and Hf. When the oxide sintered body is subjected to X-ray diffraction, (1) InGaZnO ₄ as a main phase, At least a part of the metal is dissolved in the InGaZnO ₄ and (2) ZnM _x O _y phase and M _x O _y phase (x and y are arbitrary integers) are not detected. It has a gist.

  In a preferred embodiment of the present invention, the content (atomic%) of the metal element contained in the oxide sintered body is set to [In], [Ga], [Zn], [M metal] ([M metal], respectively). Is the total amount of metal elements contained in the oxide sintered body), the ratio of [M metal] to [In] + [Ga] + [Zn] + [M metal] is 0.01. It is more than 0.05.

  In a preferred embodiment of the present invention, the contents (atomic%) of the metal elements contained in the oxide sintered body are [In], [Ga], and [Zn], respectively, and [In] + [Ga] + [In] ratio: [Ga] ratio: [Zn] where the ratio of [In], [Ga], and [Zn] to [Zn] is [In] ratio, [Ga] ratio, and [Zn] ratio, respectively. The ratio is controlled in the range of 0.32 to 0.34: 0.32 to 0.34: 0.32 to 0.34.

  In a preferred embodiment of the present invention, the oxide sintered body has a relative density of 90% or more and a specific resistance of 0.1 Ωcm or less.

  Moreover, the sputtering target of the present invention that has solved the above-mentioned problems is a sputtering target obtained using the above oxide sintered body, and has a relative density of 90% or more and a specific resistance of 0.1 Ωcm or less. It is what has.

  ADVANTAGE OF THE INVENTION According to this invention, the oxide sintered compact and sputtering target which are excellent in electroconductivity and have a high relative density are obtained. Moreover, according to the present invention, a sputtering target having excellent direct current discharge stability, less abnormal discharge during film formation, and excellent in-plane uniformity and film quality stability can be obtained. When the sputtering target of the present invention is used, an oxide semiconductor film can be stably formed at low cost by a direct current sputtering method that facilitates high-speed film formation, and thus productivity is improved.

FIG. 1 is a diagram showing a basic process for producing an oxide sintered body and a sputtering target of the present invention. FIG. 2 is a graph showing the X-ray diffraction result of the oxide sintered body (Si ratio = 0.01) of the example of the present invention in Experimental Example 1. FIG. 3 is a graph showing an X-ray diffraction result of an oxide sintered body (Si ratio = 0.031) of an example of the present invention in Experimental Example 4. FIG. 4 is a graph showing an X-ray diffraction result of the oxide sintered body (Si ratio = 0.05) of Comparative Example in Experimental Example 7.

  The present inventors have disclosed an oxide for a sputtering target that has high conductivity and high relative density and can be applied to a direct current sputtering method for an oxide (IGZO) semiconductor containing In, Ga, and Zn. In order to provide a sintered body, investigation has been repeated.

As a result, (a) each of oxides of metal elements (In, Ga, Zn) constituting IGZO and oxides of at least one metal (M metal) selected from the group consisting of Si, Ni, and Hf If an M metal-containing IGZO sintered body obtained by mixing and sintering powder is particularly excellent in direct current plasma discharge stability during physical vapor deposition, there is little abnormal discharge during film formation, and the density is high A high-quality oxide sintered body for a sputtering target is obtained. (A) Specifically, when the oxide sintered body is subjected to X-ray diffraction, (1) InGaZnO ₄ is used as a main phase, and at least M metal A part is dissolved in the InGaZnO ₄ , and (2) the ZnM _x O _y phase and the M _x O _y phase (x and y are arbitrary integers) that are spinel compounds are not detected. When you have the right structure (C) And, in order to obtain the M metal-containing IGZO sintered body of the present invention having such a phase structure, the ratio of the total amount of M metal in all metal elements is set within a predetermined range. The present inventors have found that the controlled mixed powder may be subjected to predetermined sintering conditions (preferably calcining at a temperature of 1250 to 1600 ° C. for 5 hours or more in a non-reducing atmosphere), thereby completing the present invention. .

First, the M metal containing IGZO sintered body of the present invention will be described in detail. As described above, the present invention, when the oxide sintered body is X-ray diffracted,
(1) InGaZnO ₄ as a main phase, at least a part of the M metal is dissolved in the InGaZnO ₄ , and
(2) It is characterized in that it is an oxide sintered body having a structure in which the ZnM _x O _y phase and M _x O _y phase (x and y are arbitrary integers), which are spinel compounds, are not detected. .

The X-ray diffraction conditions in the present invention are as follows.
Analysis device: “X-ray diffractometer RINT-1500” manufactured by Rigaku Corporation
Analysis conditions Target: Cu
Monochromatic: Uses a monochrome mate (Kα)
Target output: 40kV-200mA
(Continuous firing measurement) θ / 2θ scanning Slit: Divergence 1/2 °, Scattering 1/2 °, Received light 0.15 mm
Monochromator light receiving slit: 0.6mm
Scanning speed: 2 ° / min
Sampling width: 0.02 °
Measurement angle (2θ): 5 to 90 °

  Next, the compound (1) detected by the X-ray diffraction or the compound (2) not detected will be described in detail.

(1) InGaZnO ₄ for InGaZnO ₄ compound (phase) is an oxide In, Ga, and Zn is formed by bonding of the oxide sintered body of the present invention. This compound is a so-called spinel-type compound, which is rich in physical properties as an electronic material and has the characteristics that the physical properties change as the crystal structure changes. In the IGZO-based oxide as in the present invention, the above compound greatly contributes to the improvement of the relative density of the oxide sintered body.

In the present invention, the InGaZnO ₄ compound is included as a main phase. Here, the “main phase” means a compound having the highest ratio among all the compounds detected by the X-ray diffraction.

At least a part of the M metal added in the present invention is dissolved in the InGaZnO ₄ compound. Preferred embodiments are those in which all of the M metal is dissolved in the InGaZnO ₄ compound, oxide sintered body only the InGaZnO ₄ compound is present in a single phase, relative density higher resistance Is also very useful.

In the present invention, as long as it does not inhibit the effects of the present invention (high relative density and low resistance), the part of the M metal _{(In A Ga B Zn C M} D) O 2 (A, B, C, D May be any integer). As will be described later, since the M metal oxide (M oxide) is a non-conductive phase, it should be as small as possible. However, as long as the effects of the present invention are not hindered (In _A Ga _B Zn _C M _D Anything containing a small amount of O ₂ is included within the scope of the present invention.

(2) ZnM _x O _y phase and M _x O _y phase (x and y are arbitrary integers) ZnM _x O _y phase and M _x O _y phase (x and y are arbitrary integers) Although the M metal constituting the oxide sintered body of the present invention is a spinel compound that can be formed by combining with oxygen (O), in the present invention, when the above X-ray diffraction is performed, these compounds are There is a feature that is not detected. The above oxide formed by oxidation of M metal (for example, ZnM _x O _y phase or M _x O _y phase such as SiO ₂ ) has high insulation and high resistance. If it is contained in a sintered body or a sputtering target, the resistance becomes high, or the resistance becomes locally high, causing arcing during plasma discharge. In addition, the oxide protruding in a cluster shape is mixed into the film, so that the semiconductor characteristics of the thin film are deteriorated and the carrier mobility is lowered. For this reason, in the present invention, the oxide phase of the M metal element is prevented from forming in the oxide sintered body by controlling the sintering conditions described later, and most of the M element is converted to In _A Ga _B. By dissolving in a Zn _C phase or the like, the film characteristics of the thin film can be stabilized and the decrease in carrier mobility can be prevented.

In the present invention, the M metal is at least one metal selected from the group consisting of Si, Ni, and Hf, as will be described later. For example, when the M metal is Si, a compound such as ZnSiO ₂ or SiO ₂ is used. Means not detected. “Not detected” means below the detection limit when the above-mentioned X-ray diffraction conditions are performed. All or most of of added M metal is confirmed that the solid solution in the In _A Ga _B Zn _C compound. Incidentally, the remaining M metal that is not dissolved in the In _A Ga _B Zn _C compound is presumed to be segregated in the solid solution or the grain boundaries such as ZnO which may be produced by the composition of the oxide sintered body .

  Next, the elements constituting the oxide sintered body of the present invention will be described in detail. The oxide sintered body of the present invention includes indium oxide, gallium oxide, zinc oxide, and powders of at least one metal (M metal) oxide selected from the group consisting of Si, Ni, and Hf. Are obtained by mixing and sintering.

  Here, the oxides of In, Ga, and Zn are compounds that form a semiconductor by controlling the carrier concentration, and the properties change from insulating to semiconductor and conductive depending on the oxygen content in the oxide. Can be changed. This is because it is known that oxygen vacancies are intentionally generated in the oxide, and the surplus electrons become carriers, and when there are a relatively small number of carriers, it becomes a semiconductor, and when there are a large number of carriers, it degenerates and becomes a conductor. It has been.

  M metal used in the present invention is an element useful for improving the characteristics of a film formed by sputtering, and was applied to an IGZO-based oxide. The M metal is selected from the group consisting of Si, Ni, and Hf, and may be used alone or in combination of two or more.

  In the present invention, [In], [Ga], [Zn], [M metal] ([M metal] is the oxide content of the metal element contained in the oxide sintered body (atomic%), respectively. (M metal) to [In] + [Ga] + [Zn] + [M metal] (hereinafter abbreviated as M metal ratio). In some cases) is preferably 0.01 or more and less than 0.05. When the M metal ratio is less than 0.01, the effect of adding the M metal cannot be obtained, and the reliability of the TFT when a thin film is formed is lowered. On the other hand, when the M metal ratio is 0.05 or more, the density of the sintered body cannot be increased to 90% or more, and the specific resistance also increases, so the DC plasma discharge is not stable and abnormal discharge occurs It becomes easy to do. A more preferable M metal ratio is 0.035 or less. In the examples described later, depending on the type of M metal, for example, when M metal = Si, the Si ratio may be abbreviated.

In the present invention, the content (atomic%) of the metal element contained in the oxide sintered body is [In], [Ga], and [Zn], respectively, and [In] ratio, [Ga] ratio, and [Zn]. ] Ratio, [In] ratio: [Ga] ratio: [Zn] ratio = 0.32 to 0.34: 0.32 to 0.34: 0.32 to 0.34. Preferably it is. That is, it is preferable that these ratios are substantially equally added at a ratio of 1: 1: 1 within an allowable range of ± 0.01. Thereby, the carrier mobility when a thin film is formed becomes high, and a high mobility of, for example, 8 cm ² / Vs or more can be obtained.

  The oxide sintered body of the present invention and the sputtering target obtained using the oxide sintered body are characterized in that the relative density is 90% or more and the specific resistance is 0.1 Ωcm or less.

(Relative density 90% or more)
The oxide sintered body of the present invention has a very high relative density, preferably 90% or more, and more preferably 95% or more. A high relative density not only can prevent the generation of cracks and nodules during sputtering, but also provides advantages such as maintaining a stable discharge continuously to the target life.

In general when the IGZO-based oxide, preferably from the viewpoint of high density of it is a sintered body that consists of only InGaZnO ₄ single phase as mentioned above, ZnM _x O by the addition of M metal oxide powder It is known that when a plurality of phases other than InGaZnO ₄ are formed by forming a _y phase, a M _x O _y phase, or the like, a relative density is likely to be lowered. On the other hand, in the present invention, since these ZnM _x O _y phases and M _x O _y phases are not included, the relative density is not lowered and 90% or more of the desired level can be secured. The oxide sintered body of the present invention contains most of M metal as a solid solution in an InGaZnO ₄ compound, and includes oxides such as (In _A Ga _B Zn _C M _D ) O _{2 to} some extent. Although obtained, such a phase structure does not inhibit the densification of the oxide sintered body and does not adversely affect the properties of the thin film.

(Specific resistance 0.1Ωcm or less)
The oxide sintered body of the present invention has a very small specific resistance, preferably 0.1 Ωcm or less, more preferably 0.05 Ωcm or less. Accordingly, film formation by a direct current sputtering method using plasma discharge using a direct current power source is possible, and physical vapor deposition (sputtering method) using a sputtering target can be efficiently performed on the production line of the display device.

  Next, a method for producing the oxide sintered body of the present invention will be described.

  The oxide sintered body of the present invention includes indium oxide, gallium oxide, zinc oxide, and powders of at least one metal (M metal) oxide selected from the group consisting of Si, Ni, and Hf. FIG. 1 shows a basic process from raw material powder to a sputtering target. Fig. 1 shows the basic steps from mixing and crushing oxide powder to drying and granulating → forming → atmospheric pressure sintering, and then processing → bonding to obtain a sputtering target. Is shown. Among the above steps, the present invention is characterized in that the sintering conditions are appropriately controlled as will be described in detail below, and the other steps are not particularly limited, and usually used steps can be appropriately selected. . Hereinafter, although each process is demonstrated, this invention is not the meaning limited to this.

  First, indium oxide powder, gallium oxide powder, zinc oxide powder, and M metal oxide powder are mixed in a predetermined ratio, mixed and pulverized. The purity of each raw material powder used is preferably about 99.99% or more. This is because the presence of a trace amount of impurity elements may impair the semiconductor characteristics of the oxide semiconductor film. The blending ratio of each raw material powder is preferably controlled so that the ratio of Zn and M metal falls within the above-described range.

  Mixing and pulverization are preferably carried out using a pot mill and adding the raw material powder together with water. The balls and beads used in these steps are preferably made of materials such as nylon, alumina, zirconia, and the like.

Next, the mixed powder obtained in the above step is dried and granulated, and then molded. In the molding, it is preferable that the powder after drying and granulation is filled in a metal mold of a predetermined size, pre-molded by a mold press, and then molded by CIP (cold isostatic pressing) or the like. In order to increase the relative density of the sintered body, it is preferable to control the molding pressure for preforming to about 0.2 tonf / cm ² or more, and the pressure at the time of molding to about 1.2 tonf / cm ² or more. It is preferable.

Next, the molded body thus obtained is fired at normal pressure. In the present invention, sintering is performed at a firing temperature of about 1250 ° C. to 1600 ° C. and a holding time of about 5 hours or more in order to obtain a desired compound phase structure (phase mainly composed of InGaZnO ₄ ) and increase the relative density. preferable. The higher the firing temperature is, the easier it is to improve the relative density of the sintered body, and it can be processed in a short time, but it is preferable because the sintered body is easily decomposed when the temperature is too high. Is preferred. More preferably, the firing temperature is about 1300 ° C. to 1550 ° C., and the holding time is about 8 hours or more. The firing atmosphere is preferably a non-reducing atmosphere. For example, it is preferable to adjust the atmosphere by introducing oxygen gas into the furnace.

  After the desired oxide sintered body is obtained as described above, the sputtering target of the present invention is obtained by processing and bonding according to a conventional method. The relative density and specific resistance of the sputtering target thus obtained are also very good as in the case of the oxide sintered body, the preferable relative density is generally 90% or more, and the preferable specific resistance is generally about 0. 0. 1 Ωcm or less.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples, and may be implemented with appropriate modifications within a scope that can meet the gist of the present invention. These are all possible and are within the scope of the present invention.

(Experimental example 1)
In Experimental Example 1 and Experimental Examples 2 and 3 to be described later, an Si-IGZO sintered body containing Si as the M metal and having an Si ratio of 0.01 was manufactured by the following method.

Indium oxide powder having a purity of 99.99%, gallium oxide powder having a purity of 99.99%, zinc oxide powder (JIS 1 type, purity 99.99%), and silica powder having a purity of 99.99% [In]: [Ga ]: [Zn]: [Si] = 33.0: 33.0: 33.0: 1.0 was mixed at an atomic ratio and mixed for 20 hours with a nylon ball mill. Next, the mixed powder obtained in the above process is dried and granulated, pre-molded with a mold press at a molding pressure of 0.5 tonf / cm ² , and then molded with CIP at a molding pressure of 3 tonf / cm ^2. Went.

  The molded body thus obtained was sintered at 1450 ° C. for 5 hours at normal pressure.

FIG. 2 shows the results of analyzing the oxide sintered body (Si-IGZO sintered body) thus obtained by X-ray diffraction under the conditions described above. As shown in FIG. 2, the oxide sintered body contains InGaZnO ₄ as a main phase and contains a small amount of (In _0.5 Ga _0.2 Zn _0.2 Si _0.1 ) O ₂ phase, but ZnSi _x O _y and SiO _2. Was not detected. Moreover, it was 91.6% when the relative density of the oxide sintered compact obtained in this way was measured by the Archimedes method. Further, when the specific resistance of the oxide sintered body was measured by a four-terminal method, it was 2.7 × 10 ⁻² Ωcm, and both the relative density and the specific resistance had good characteristics.

  Table 1 summarizes the results of relative density and specific resistance of the oxide sintered body containing Si as the M metal. Table 2 summarizes the X-ray diffraction results of the oxide sintered bodies.

Further, the sintered body was processed into a shape of 4 inches φ and 5 mmt and bonded to a backing plate to obtain a sputtering target. The sputtering target thus obtained was attached to a sputtering apparatus, and DC (direct current) magnetron sputtering was performed. The sputtering conditions were a DC sputtering power of 150 W, an Ar / 0.1 volume% O ₂ atmosphere, and a pressure of 0.8 mTorr. As a result, no abnormal discharge (arcing) was observed, and it was confirmed that the discharge was stable.

  Moreover, the relative density and specific resistance of the sputtering target thus obtained are the same as the values of the oxide sintered body, and the conditions specified in the present invention (relative density of 90% or more, specific resistance of 0.1 Ωcm) The following was satisfied.

(Experimental example 2)
In Example 1 described above, an oxide sintered body was obtained by performing an experiment in the same manner as in Example 1 except that sintering was performed at 1400 ° C. for 8 hours. Analysis by diffraction revealed that InGaZnO ₄ was contained as the main phase and a small amount of (In _0.5 Ga _0.2 Zn _0.2 Si _0.1 ) O ₂ phase was contained, but ZnSi _x O _y and SiO ₂ were not detected ( (See Table 2).

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the relative density = 93.7% and the specific resistance = 4.0 × 10 ^−2. It was Ωcm and had good characteristics in both relative density and specific resistance (see Table 1).

  Furthermore, when the above sintered body was used and sputtering was performed in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, the relative density and specific resistance of the sputtering target thus obtained are the same as the values of the oxide sintered body, and the conditions specified in the present invention (relative density of 90% or more, specific resistance of 0.1 Ωcm) The following was satisfied.

(Experimental example 3)
In Example 1 described above, except that sintering was performed at 1500 ° C. for 5 hours, an experiment was performed in the same manner as in Example 1 above to obtain an oxide sintered body. Analysis by diffraction revealed that InGaZnO ₄ was contained as the main phase and a small amount of (In _0.5 Ga _0.2 Zn _0.2 Si _0.1 ) O ₂ phase was contained, but ZnSi _x O _y and SiO ₂ were not detected ( (See Table 2).

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the relative density = 92.3% and the specific resistance = 3.3 × 10 ^−2. It was Ωcm and had good characteristics in both relative density and specific resistance (see Table 1).

  Furthermore, when the above sintered body was used and sputtering was performed in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, the relative density and specific resistance of the sputtering target thus obtained are the same as the values of the oxide sintered body, and the conditions specified in the present invention (relative density of 90% or more, specific resistance of 0.1 Ωcm) The following was satisfied.

(Experimental example 4)
In Experimental Example 4 and Experimental Examples 5 and 6 to be described later, an Si-IGZO sintered body containing Si as the M metal and having an Si ratio of 0.031 was manufactured by the following method.

Specifically, in Experimental Example 1 described above, [In]: [Ga]: [Zn]: [Si] = 32.3: 32.3: 32.3: 3.1 are blended at an atomic ratio, and An oxide sintered body was obtained by conducting an experiment in the same manner as in Experimental Example 1 except that sintering was performed at 1350 ° C. for 8 hours, and then analysis by X-ray diffraction was performed under the conditions described above. . The result is shown in FIG. As shown in FIG. 3, the oxide sintered body contains InGaZnO ₄ as a main phase and contains a small amount of (In _0.5 Ga _0.2 Zn _0.2 Si _0.1 ) O ₂ phase, but ZnSi _x O _y and SiO _2. Was not detected (see Table 2).

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the relative density = 91.1% and the specific resistance = 5.6 × 10 ^−2. It was Ωcm and had good characteristics in both relative density and specific resistance (see Table 1).

  Furthermore, when the above sintered body was used and sputtering was performed in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, the relative density and specific resistance of the sputtering target thus obtained are the same as the values of the oxide sintered body, and the conditions specified in the present invention (relative density of 90% or more, specific resistance of 0.1 Ωcm) The following was satisfied.

(Experimental example 5)
In Example 4 described above, an oxide sintered body was obtained by performing an experiment in the same manner as in Example 4 except that sintering was performed at 1450 ° C. for 5 hours. When analysis by diffraction was performed, InGaZnO ₄ was contained as a main phase and a small amount of (In _0.5 Ga _0.2 Zn _0.2 Si _0.1 ) O ₂ phase was contained, but ZnSi _x O _y and SiO ₂ were not detected. (See Table 2).

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the relative density = 90.8% and the specific resistance = 6.1 × 10 ^−2. It was Ωcm and had good characteristics in both relative density and specific resistance (see Table 1).

  Furthermore, when the above sintered body was used and sputtering was performed in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, the relative density and specific resistance of the sputtering target thus obtained are the same as the values of the oxide sintered body, and the conditions specified in the present invention (relative density of 90% or more, specific resistance of 0.1 Ωcm) The following was satisfied.

(Experimental example 6)
In Example 4 described above, an oxide sintered body was obtained by performing an experiment in the same manner as in Example 1 except that sintering was performed at 1550 ° C. for 5 hours. When analysis by diffraction was performed, InGaZnO ₄ was contained as a main phase and a small amount of (In _0.5 Ga _0.2 Zn _0.2 Si _0.1 ) O ₂ phase was contained, but ZnSi _x O _y and SiO ₂ were not detected. (See Table 2).

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the relative density = 90.2% and the specific resistance = 4.1 × 10 ^−2. It was Ωcm and had good characteristics in both relative density and specific resistance (see Table 1).

  Furthermore, when the above sintered body was used and sputtering was performed in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, the relative density and specific resistance of the sputtering target thus obtained are the same as the values of the oxide sintered body, and the conditions specified in the present invention (relative density of 90% or more, specific resistance of 0.1 Ωcm) The following was satisfied.

(Experimental example 7)
In Experimental Example 7 and Experimental Examples 8 and 9 to be described later, an Si-IGZO sintered body containing Si as the M metal and having an Si ratio of 0.05 was manufactured by the following method.

Specifically, in Experimental Example 1 described above, [In]: [Ga]: [Zn]: [Si] = 31.7: 31.7: 31.6: 4.9 is blended at an atomic ratio, and Except that sintering was performed at 1200 ° C. for 5 hours, an experiment was performed in the same manner as in Experimental Example 1 to obtain an oxide sintered body, and then analysis by X-ray diffraction was performed under the conditions described above. . The result is shown in FIG. As shown in FIG. 4, the oxide sintered body contained InGaZnO ₄ as a main phase, and also contained a small amount of (In _0.5 Ga _0.2 Zn _0.2 Si _0.1 ) O ₂ phase and a small amount of ZnSi _x O _y . (See Table 2).

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the relative density was as low as 77.4%, and the specific resistance was 1.9 × 10. ^It was as high as ^-1 Ωcm (see Table 1).

  Further, when the above sintered body was used and sputtering was performed in the same manner as in Experimental Example 1, discharge occurred due to arcing during sputtering. Moreover, the relative density and specific resistance of the sputtering target thus obtained are the same as the values of the oxide sintered body, and the conditions specified in the present invention (relative density of 90% or more, specific resistance of 0.1 Ωcm) Below).

(Experimental example 8)
In Example 7 described above, an oxide sintered body was obtained by performing an experiment in the same manner as in Example 7 except that sintering was performed at 1350 ° C. for 8 hours. As a result of analysis by diffraction, as in Experimental Example 7, the oxide sintered body contains InGaZnO ₄ as a main phase, a small amount of (In _0.5 Ga _0.2 Zn _0.2 Si _0.1 ) O ₂ phase, and a small amount of ZnSi. _x O _y was also included (see Table 2).

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the specific resistance was as good as 6.5 × 10 ⁻² Ωcm. The relative density was as low as 85.7% (see Table 1).

  Furthermore, when sputtering was performed using the above sintered body in the same manner as in Experimental Example 1, abnormal discharge due to arcing occurred during sputtering. Moreover, the relative density and specific resistance of the sputtering target thus obtained were the same as the values of the oxide sintered body, and the relative density was outside the range defined in the present invention.

(Experimental example 9)
In Example 7 described above, an oxide sintered body was obtained by performing an experiment in the same manner as in Example 7 except that sintering was performed at 1450 ° C. for 5 hours. Analysis by diffraction revealed that the oxide sintered body contained InGaZnO ₄ as a main phase and also contained a trace amount of ZnSi _x O _y (see Table 2).

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the specific resistance was as good as 8.9 × 10 ⁻² Ωcm. The relative density was as low as 79.8% (see Table 1).

  Furthermore, when sputtering was performed using the above sintered body in the same manner as in Experimental Example 1, abnormal discharge due to arcing occurred during sputtering. Moreover, the relative density and specific resistance of the sputtering target thus obtained were the same as the values of the oxide sintered body, and the relative density was outside the range defined in the present invention.

(Experimental example 10)
In Experimental Example 10, a Ni-IGZO sintered body (Ni ratio = 0.031) containing Ni as the M metal was manufactured by the following method.

Specifically, in Experimental Example 4 described above, the same as Experimental Example 4 except that Ni oxide powder having a purity of 99.99% was used as the M metal and sintering was performed at 1500 ° C. for 8 hours. After conducting an experiment to obtain an oxide sintered body, analysis by X-ray diffraction was performed under the above-described conditions. As a result, it contained InGaZnO ₄ as a main phase and contained a small amount of (In _0.5 Ga _0.2 Zn _0.2 Ni _0.1 ). Although an O ₂ phase was contained, ZnNi _x O _y and NiO ₂ were not detected.

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the relative density = 91.0% and the specific resistance = 5.2 × 10 ^−2. It was Ωcm, and both the relative density and specific resistance had good characteristics.

  Furthermore, when the above sintered body was used and sputtering was performed in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, the relative density and specific resistance of the sputtering target thus obtained are the same as the values of the oxide sintered body, and the conditions specified in the present invention (relative density of 90% or more, specific resistance of 0.1 Ωcm) The following was satisfied.

(Experimental example 11)
In Experimental Example 11, a Hf-IGZO sintered body (Hf ratio = 0.031) containing Hf as M metal was manufactured by the following method.

Specifically, an oxide sintered body was obtained by performing an experiment in the same manner as in Experimental Example 6 except that in Example 6 described above, oxidized Hf powder having a purity of 99.99% was used as the M metal. Later, when analysis by X-ray diffraction was performed under the above-described conditions, it contained InGaZnO ₄ as the main phase and contained a small amount of (In _0.5 Ga _0.2 Zn _0.2 Hf _0.1 ) O ₂ phase, but ZnHf _x O _y. And HfO were not detected.

Further, when the relative density and specific resistance of the oxide sintered body thus obtained were measured in the same manner as in Experimental Example 1, the relative density = 90.6% and the specific resistance = 6.9 × 10 ^−2. It was Ωcm, and both the relative density and specific resistance had good characteristics.

  Furthermore, when the above sintered body was used and sputtering was performed in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, the relative density and specific resistance of the sputtering target thus obtained are the same as the values of the oxide sintered body, and the conditions specified in the present invention (relative density of 90% or more, specific resistance of 0.1 Ωcm) The following was satisfied.

From the above experimental results, the IGZO oxide sintered body containing M metal used in the present invention, as a result of X-ray diffraction, separated the Mn metal oxide ZnM _x O _y phase and M _x O _y phase. It was confirmed that it was not formed and contained InGaZnO ₄ as a main phase. As a result, it was found that the oxide sintered body of the present invention and the sputtering target obtained using the sintered body have a high relative density and a low specific resistance, and have extremely good characteristics.

Claims (5)

Obtained by mixing and sintering indium oxide; gallium oxide; zinc oxide; and powders of at least one metal (M metal) oxide selected from the group consisting of Si, Ni, and Hf An oxide sintered body,
When X-ray diffraction of the oxide sintered body,
(1) InGaZnO ₄ as a main phase, at least a part of the M metal is dissolved in the InGaZnO ₄ , and
(2) An oxide sintered body characterized in that a ZnM _x O _y phase and an M _x O _y phase (x and y are arbitrary integers) are not detected.   [In], [Ga], [Zn], and [M metal] ([M metal] are contained in the oxide sintered body, respectively. The ratio of [M metal] to [In] + [Ga] + [Zn] + [M metal] is 0.01 or more and less than 0.05. Item 2. The oxide sintered body according to Item 1.   The contents (atomic%) of metal elements contained in the oxide sintered body are [In], [Ga], and [Zn], respectively, and [In] with respect to [In] + [Ga] + [Zn], When the ratios of [Ga] and [Zn] are [In] ratio, [Ga] ratio, and [Zn] ratio, [In] ratio: [Ga] ratio: [Zn] ratio = 0.32-0. 34: 0.32-0.34: The oxide sintered compact of Claim 1 or 2 currently controlled by the range of 0.32-0.34.   The oxide sintered body according to any one of claims 1 to 3, which has a relative density of 90% or more and a specific resistance of 0.1 Ωcm or less.   A sputtering target obtained by using the oxide sintered body according to claim 1, wherein the sputtering target has a relative density of 90% or more and a specific resistance of 0.1 Ωcm or less.