WO2012039351A1 - Oxide sintered compact and sputtering target - Google Patents

Oxide sintered compact and sputtering target Download PDF

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WO2012039351A1
WO2012039351A1 PCT/JP2011/071195 JP2011071195W WO2012039351A1 WO 2012039351 A1 WO2012039351 A1 WO 2012039351A1 JP 2011071195 W JP2011071195 W JP 2011071195W WO 2012039351 A1 WO2012039351 A1 WO 2012039351A1
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sintered body
metal
oxide
oxide sintered
experimental example
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PCT/JP2011/071195
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French (fr)
Japanese (ja)
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後藤　裕史
祐紀 岩崎
中井　淳一
陽一郎 米田
得平　雅也
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株式会社コベルコ科研
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/453—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
    • C04B35/457—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates based on tin oxides or stannates
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    • C04B35/453—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
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    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
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    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
    • C23C14/3414—Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
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    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3286—Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
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    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/02631—Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation

Definitions

  • the present invention relates to an oxide sintered body and a sputtering target used when an oxide semiconductor thin film of a thin film transistor (TFT) used in a display device such as a liquid crystal display or an organic EL display is formed by a sputtering method.
  • TFT thin film transistor
  • 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 deposited 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.
  • 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.
  • an In-containing amorphous oxide semiconductor (In—Ga—Zn—O, In—Zn—O, etc.) can be cited, but the rare metal In is used. Therefore, there is a concern that material costs will increase in mass production processes. Therefore, a ZTO-based oxide semiconductor that has been made amorphous by adding Sn to Zn has been proposed as an oxide semiconductor that does not contain expensive In and can reduce material costs and is suitable for mass production.
  • No. 4 discloses an oxide sintered body and a sputtering target useful for producing the ZTO-based oxide semiconductor film.
  • Patent Document 1 proposes a method of suppressing the occurrence of abnormal discharge and cracking during sputtering by performing long-time baking and controlling the structure so as not to contain a tin oxide phase.
  • Patent Document 2 also suppresses abnormal discharge during sputtering by increasing the density of the ZTO-based sintered body by performing a two-step process of a low-temperature calcined powder manufacturing process at 900 to 1300 ° C. and a main baking process.
  • a method has been proposed.
  • Patent Document 3 proposes a method of improving the conductivity and increasing the density by including a spinel-type AB 2 O 4 compound.
  • Patent Document 4 proposes a method of obtaining a dense ZTO-based sintered body by performing two steps of a low-temperature calcined powder manufacturing process at 900 to 1100 ° C. and a main baking process.
  • 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.
  • a sputtering target that can be manufactured not by a high frequency (RF) sputtering method but by a direct current sputtering method that facilitates high-speed film formation.
  • Patent Document 1 described above has not been studied from the viewpoint of increasing the density, and is insufficient to stably and continuously perform DC discharge.
  • Patent Document 2 has not been studied from the viewpoint of improving the conductivity of the oxide sintered body, and is still insufficient for stable and continuous DC discharge.
  • Patent Document 3 described above has been studied from the viewpoints of higher density and higher conductivity, but contains a highly insulating Ga 2 O 3 phase in the sputtering target, and the semiconductor characteristics of the thin film. Therefore, it was insufficient to ensure homogeneity and film quality stability within the sputtering target plane.
  • Patent Document 4 is premised on an RF sputtering method that is inferior in productivity, and is difficult to apply to mass production on a large glass substrate.
  • 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 has solved the above problems is at least one selected from the group consisting of zinc oxide; tin oxide; Al, Hf, Ta, Ti, Nb, Mg, Ga, and rare earth elements And an oxide sintered body obtained by mixing and sintering the metal (M metal) oxide powder, and when the oxide sintered body is X-ray diffracted, a Zn 2 SnO 4 compound Is detected, but the ZnM X O y phase and M X O y phase (x and y are arbitrary integers) are not detected.
  • the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [ The ratio of [Zn] to Sn] + [M metal] is 0.35 or more and 0.75 or less.
  • the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [M metal] is 0.01 or more and 0.30 or less.
  • the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [M metal] is 0.01 or more and 0.30 or less.
  • the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [M metal] is not less than 0.01 and not more than 0.30, and the ratio of [M metal] to [Zn] + [Sn] + [M metal] is It is 0.01 or more and 0.30 or less.
  • the oxide sintered body according to any one of the above has a relative density of 90% or more and a specific resistance of 1 ⁇ cm or less.
  • the sputtering target of the present invention that has solved the above problems is a sputtering target obtained using the oxide sintered body according to any of the above, and has a relative density of 90% or more and a specific resistance of 1 ⁇ cm or less. It has a gist at some point.
  • an oxide sintered body and a sputtering target that are excellent in conductivity and have a high relative density can be obtained. Further, according to the present invention, a sputtering target having excellent direct current discharge stability, excellent in-plane uniformity and film quality stability can be obtained.
  • an oxide semiconductor film can be formed at low cost by a direct current sputtering method that facilitates high-speed film formation, so that 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.
  • the present inventors have disclosed at least one metal (M metal) selected from the group consisting of zinc oxide (ZnO); tin oxide (SnO); Al, Hf, Ta, Ti, Nb, Mg, Ga and rare earth elements.
  • M metal selected from the group consisting of zinc oxide (ZnO); tin oxide (SnO); Al, Hf, Ta, Ti, Nb, Mg, Ga and rare earth elements.
  • Oxide oxide (M metal oxide) and an oxide sintered body obtained by mixing and sintering hereinafter sometimes abbreviated as M metal-containing ZTO oxide sintered body.
  • M metal exists as a ZnM X O y phase and M X O y phase (x and y are arbitrary integers) which are spinel type compounds.
  • M metal is contained in Zn 2 SnO 4 (in addition, when one or both of SnO 2 and ZnO are present, they are contained in Zn 2 SnO 4 or in SnO 2 and in ZnO.
  • the M metal-containing ZTO-based oxide sintered body of the present invention will be described in detail.
  • a Zn 2 SnO 4 compound is detected, but a ZnM X O y phase and a M X O y phase (x , Y is an arbitrary integer), and is characterized in that it is an oxide sintered body having such a structure that it is 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 (K ⁇ ) Target output: 40kV-200mA (Continuous firing measurement) ⁇ / 2 ⁇ 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 (2 ⁇ ): 5 to 90 °
  • the Zn 2 SnO 4 compound (phase) is formed by bonding ZnO and SnO 2 constituting 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.
  • SnO 2 or ZnO may be included slightly.
  • the composition ratio of Zn and Sn there is a case where SnO 2 or ZnO as well Zn 2 SnO 4 compound is detected, the above SnO 2 or ZnO is a DC discharge stability of the sputtering if trace amount This is because there is no adverse effect.
  • the ZnM X O y phase and the M X O y phase are spinels that can be formed by combining M metal constituting the oxide sintered body of the present invention with oxygen (O).
  • O oxygen
  • the present invention is characterized in that these compounds are not detected when the X-ray diffraction is performed. Since these compounds (for example, Ta 2 O 5 and Al 2 O 3 ) have high insulation properties, if an oxide of M metal is contained in an oxide sintered body or sputtering target, Al that protrudes in a cluster shape.
  • oxides and Ta oxides are mixed into the film, so that the semiconductor characteristics of the thin film are deteriorated and the carrier mobility is lowered.
  • an oxide phase of M element is prevented from being formed in the oxide sintered body under the sintering conditions described later, and the M element is dissolved in the Zn 2 SnO 4 phase, etc. The characteristics can be stabilized and a decrease in carrier mobility can be prevented.
  • M metal is at least one metal selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga and rare earth elements, as will be described later.
  • M metal is Al
  • ZnAl 2 O 4 and Al 2 O 3 are not detected. “Not detected” means below the detection limit when the above-mentioned X-ray diffraction conditions are performed. It has been confirmed that all or most of the added M metal is dissolved in the Zn 2 SnO 4 compound. The remaining M metal that is not dissolved in the Zn 2 SnO 4 compound is presumed to be dissolved in SnO 2 or ZnO that can be generated by the composition of the oxide sintered body or segregated at the grain boundaries.
  • the oxide sintered body of the present invention comprises zinc oxide, tin oxide, and at least one metal (M metal) selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga, and rare earth elements. It is obtained by mixing and sintering each powder of oxide.
  • M metal metal selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga, and rare earth elements. It is obtained by mixing and sintering each powder of oxide.
  • oxides of ZnO and SnO are compounds that form a semiconductor by controlling the carrier concentration, and change the properties from insulating to semiconductor and conductive depending on the oxygen content in the oxide. Can do. 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 a ZTO-based oxide in the present invention.
  • M metal is selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga and rare earth elements and may be used alone or in combination of two or more.
  • the “rare earth element” is an element group in which Sc (scandium) and Y (yttrium) are added to a lanthanoid element (a total of 15 elements from La of atomic number 57 to Lu of atomic number 71 in the periodic table).
  • one or more rare earth elements can be used.
  • the rare earth elements Gd, Nd, La, and Y are preferable from the viewpoint of semiconductor characteristics, and La and Y are more preferable.
  • Al, Nb, Ti, La, and Mg are preferable from the viewpoint of semiconductor characteristics, and Al, Nb, and La are more preferable.
  • Zn ratio when the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [Sn] + [ [Zn] to [M metal] ratio [[Zn] / ([Zn] + [Sn] + [M metal]), hereinafter may be abbreviated as Zn ratio.
  • Zn ratio Is preferably 0.35 or more and 0.75 or less.
  • the Zn ratio is less than 0.35, fine processing (processing with high accuracy) of a thin film formed by sputtering is difficult, and etching residues are likely to occur.
  • the Zn ratio exceeds 0.75, the carrier mobility of the thin film decreases and falls below the desired level of 5 cm 2 / Vs. More preferably, it is 0.5 or more and 0.7 or less.
  • 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 1 ⁇ cm or less.
  • 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.
  • a ZTO-based oxide it is preferable that it is composed only of a Zn 2 SnO 4 single phase from the viewpoint of increasing the density of the sintered body, and by adding an M metal oxide powder, a ZnM X O y phase
  • a ZnM X O y phase it is known that when a plurality of phases other than Zn 2 SnO 4 are formed by forming an M x O y phase or the like, the relative density tends to decrease.
  • 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 exists as a single phase in which all or most of the M metal is dissolved in Zn 2 SnO 4 , and may contain ZnO or SnO 2 to some extent. However, such a phase structure does not hinder densification of the oxide sintered body and does not adversely affect the properties of the thin film.
  • the oxide sintered body of the present invention has a small specific resistance, preferably 1 ⁇ cm or less, more preferably 0.1 ⁇ cm 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.
  • the oxide sintered body of the present invention comprises zinc oxide, tin oxide, and at least one metal (M metal) selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga, and rare earth elements.
  • FIG. 1 shows a basic process from a raw material powder to a sputtering target, which is an oxide sintered body obtained by mixing and sintering oxide powders.
  • oxide powder is mixed and pulverized, dried and granulated, molded, subjected to atmospheric pressure sintering, heat-treated, and then the oxide sintered body is processed and bonded to obtain a sputtering target.
  • the basic process is shown.
  • the present invention is characterized in that the sintering conditions and the subsequent heat treatment conditions are appropriately controlled as described in detail below, and the other steps are not particularly limited, and the normally used steps are appropriately selected. You can choose.
  • this invention is not the meaning limited to this.
  • zinc oxide powder, tin 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 performed by 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.
  • the mixed powder obtained in the above step is dried and granulated, and then molded.
  • 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.
  • CIP cold isostatic pressing
  • the molded body thus obtained is fired at normal pressure.
  • the firing temperature is about 1450 ° C. to 1600 ° C.
  • 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.
  • heat treatment is performed on the sintered body to obtain the oxide sintered body of the present invention.
  • the heat treatment temperature about 1000 ° C. or more and the holding time: about 8 hours or more in order to enable plasma discharge with a DC power source.
  • the specific resistance of the sintered body is generally improved from 100 ⁇ cm to 0.1 ⁇ cm.
  • the firing temperature is about 1100 ° C. or more, and the holding time is about 10 hours or more.
  • the firing temperature exceeds 1300 ° C., Zn evaporates and component fluctuations occur, so it is preferable to set it to 1300 ° C. or lower.
  • the holding time is preferably controlled to be approximately 30 hours or less in consideration of cost reduction and the like.
  • the heat treatment atmosphere is preferably a reducing atmosphere.
  • the sputtering target of the present invention can be 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, like the oxide sintered body, and the preferable relative density is approximately 90% or more, and the preferable specific resistance is approximately 1 ⁇ cm or less. It is.
  • Zinc oxide powder JIS 1 type, purity 99.99%
  • granulating a mixed powder obtained in the above step was preformed molding pressure 0.5tonf / cm 2 at a die press, were present molding at a molding pressure of 3tonf / cm 2 at CIP .
  • the molded body thus obtained was sintered by holding at 1500 ° C. for 7 hours at normal pressure.
  • Oxygen gas was introduced into the sintering furnace and sintered in an oxygen atmosphere.
  • it was introduced into a heat treatment furnace and heat treated at 1200 ° C. for 10 hours.
  • Nitrogen gas was introduced into the heat treatment furnace and heat treatment was performed in a reducing atmosphere.
  • FIG. 2 and Table 1 show the results of analyzing the oxide sintered body (Ta—ZTO sintered body) thus obtained by X-ray diffraction analysis under the conditions described above. As shown in FIG. 2, although the oxide sintered body contains Zn 2 SnO 4 , no Ta oxide (Ta 2 O 5 or the like) was detected.
  • the sintered body was processed into a shape of 4 inches ⁇ 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.
  • the relative density of the sputtering target thus obtained was measured by Archimedes method and found to be 90% or more. Moreover, when the specific resistance of the said sputtering target was measured by the four probe method, it was 1 ohm-cm or less, and all obtained the favorable result.
  • the oxide sintered body contained Zn 2 SnO 4, but no Al oxide (Al 2 O 3 or the like) was detected.
  • the oxide sintered body contains Zn 2 SnO 4, but no Ga oxide (Ga 2 O 3 or the like) was detected.
  • the oxide sintered body contained Zn 2 SnO 4, but no oxide of Hf (such as HfO 2 ) was detected.
  • the oxide sintered body contained Zn 2 SnO 4, but no Ti oxide (TiO 2 or the like) was detected.
  • the oxide sintered body contained Zn 2 SnO 4, but no Mg oxide (such as MgO) was detected.
  • the oxide sintered body contained Zn 2 SnO 4, but no Ga oxide (Ga 2 O 3 or the like) was detected.
  • the oxide sintered body contained Zn 2 SnO 4, but no La oxide (such as La 2 O 3 ) was detected.
  • the oxide sintered body contained Zn 2 SnO 4 .
  • the columns of “M metal oxide”, “ZnM X O y ”, and “M X O y phase” in Table 1 are “-(none)”.
  • the ZTO 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 did not form. 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.

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Abstract

Provided is an oxide sintered compact that has both high conductivity and relative density and is ideal for the forming of an oxide semiconductor film for a display device. The oxide sintered compact of the present invention is obtained by mixing and sintering, each in powder form, zinc oxide, tin oxide, and an oxide of at least one metal (M metal) selected from the group comprising Al, Hf, Ta, Ti, Nb, Mg, Ga and rare earth elements, wherein, when the oxide sintered compact is subjected to X-ray diffraction, a Zn2SnO4 compound is detected but spinel compounds in the form of a ZnMxOy phase or an MxO­y phase (where x and y are arbitrary integers) are not detected.

Description

酸化物焼結体およびスパッタリングターゲットOxide sintered body and sputtering target
　本発明は、液晶ディスプレイや有機ＥＬディスプレイなどの表示装置に用いられる薄膜トランジスタ（ＴＦＴ）の酸化物半導体薄膜をスパッタリング法で成膜するときに用いられる酸化物焼結体およびスパッタリングターゲットに関するものである。 The present invention relates to an oxide sintered body and a sputtering target used when an oxide semiconductor thin film of a thin film transistor (TFT) used in a display device such as a liquid crystal display or an organic EL display is formed by a sputtering method.
　ＴＦＴに用いられるアモルファス（非晶質）酸化物半導体は、汎用のアモルファスシリコン（ａ－Ｓｉ）に比べて高いキャリア移動度を有し、光学バンドギャップが大きく、低温で成膜できるため、大型・高解像度・高速駆動が要求される次世代ディスプレイや、耐熱性の低い樹脂基板などへの適用が期待されている。上記酸化物半導体（膜）の形成に当たっては、当該膜と同じ材料のスパッタリングターゲットをスパッタリングするスパッタリング法が好適に用いられている。スパッタリング法で形成された薄膜は、イオンプレーティング法や真空蒸着法、電子ビーム蒸着法で形成された薄膜に比べ、膜面方向（膜面内）における成分組成や膜厚などの面内均一性に優れており、スパッタリングターゲットと同じ成分組成の薄膜を形成できるという長所を有しているからである。スパッタリングターゲットは、通常、酸化物粉末を混合、焼結し、機械加工を経て形成されている。 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 deposited 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.
　表示装置に用いられる酸化物半導体の組成として、例えばＩｎ含有の非晶質酸化物半導体（Ｉｎ－Ｇａ－Ｚｎ－Ｏ、Ｉｎ－Ｚｎ－Ｏなど）が挙げられるが、希少金属であるＩｎを使用しており、大量生産プロセスでは材料コストの上昇が懸念される。そこで、高価なＩｎを含まず材料コストを低減でき、大量生産に適した酸化物半導体として、ＺｎにＳｎを添加してアモルファス化したＺＴＯ系の酸化物半導体が提案されており、特許文献１～４には、当該ＺＴＯ系酸化物半導体膜の製造に有用な酸化物焼結体およびスパッタリングターゲットが開示されている。 As the composition of the oxide semiconductor used for the display device, for example, an In-containing amorphous oxide semiconductor (In—Ga—Zn—O, In—Zn—O, etc.) can be cited, but the rare metal In is used. Therefore, there is a concern that material costs will increase in mass production processes. Therefore, a ZTO-based oxide semiconductor that has been made amorphous by adding Sn to Zn has been proposed as an oxide semiconductor that does not contain expensive In and can reduce material costs and is suitable for mass production. No. 4 discloses an oxide sintered body and a sputtering target useful for producing the ZTO-based oxide semiconductor film.
　このうち特許文献１には、長時間の焼成を行なって酸化スズ相を含有しないように組織を制御することにより、スパッタリング中の異常放電や割れの発生を抑制する方法が提案されている。また特許文献２には、９００～１３００℃の低温の仮焼粉末製造工程と本焼成工程の２段階工程を行なってＺＴＯ系焼結体を高密度化することにより、スパッタリング中の異常放電を抑制する方法が提案されている。特許文献３は、スピネル型のＡＢ2Ｏ4化合物を含有させることによって導電性を向上させ、かつ高密度化する方法が提案されている。また、特許文献４には、９００～１１００℃の低温の仮焼粉末製造工程と本焼成工程の２段階の工程を行なって緻密なＺＴＯ系焼結体を得る方法が提案されている。 Among these, Patent Document 1 proposes a method of suppressing the occurrence of abnormal discharge and cracking during sputtering by performing long-time baking and controlling the structure so as not to contain a tin oxide phase. Patent Document 2 also suppresses abnormal discharge during sputtering by increasing the density of the ZTO-based sintered body by performing a two-step process of a low-temperature calcined powder manufacturing process at 900 to 1300 ° C. and a main baking process. A method has been proposed. Patent Document 3 proposes a method of improving the conductivity and increasing the density by including a spinel-type AB 2 O 4 compound. Patent Document 4 proposes a method of obtaining a dense ZTO-based sintered body by performing two steps of a low-temperature calcined powder manufacturing process at 900 to 1100 ° C. and a main baking process.
特開２００７－２７７０７５号公報JP 2007-277075 A 特開２００８－６３２１４号公報JP 2008-63214 A 特開２０１０－１８４５７号公報JP 2010-18457 A 特開２０１０－３７１６１号公報JP 2010-37161 A
　表示装置用酸化物半導体膜の製造に用いられるスパッタリングターゲットおよびその素材である酸化物焼結体は、導電性に優れ、且つ高い相対密度を有していることが望まれる。また生産性や製造コストなどを考慮すると、高周波(ＲＦ)スパッタリング法でなく、高速成膜が容易な直流スパッタリング法で製造可能なスパッタリングターゲットの提供が望まれている。 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 productivity, manufacturing cost, and the like, it is desired to provide a sputtering target that can be manufactured not by a high frequency (RF) sputtering method but by a direct current sputtering method that facilitates high-speed film formation.
　しかしながら、前述した特許文献１は高密度化という観点から検討されたものではなく、直流放電を安定・継続して実施するには不十分であった。また特許文献２は、酸化物焼結体の導電性を向上するという観点から検討されたものではなく、やはり、直流放電を安定・継続して実施するには不十分であった。 However, Patent Document 1 described above has not been studied from the viewpoint of increasing the density, and is insufficient to stably and continuously perform DC discharge. Further, Patent Document 2 has not been studied from the viewpoint of improving the conductivity of the oxide sintered body, and is still insufficient for stable and continuous DC discharge.
　一方、前述した特許文献３は、高密度化および高導電性の観点から検討されたものであるが、絶縁性の高いＧａ2Ｏ3相をスパッタリングターゲット中に含有しており、薄膜の半導体特性が損なわれるため、スパッタリングターゲット面内での均質性、および膜質安定性を確保するには不十分であった。また、特許文献４は、生産性に劣るＲＦスパッタリング法を前提としたものであり、大型ガラス基板上などの大量生産への適用は困難である。 On the other hand, Patent Document 3 described above has been studied from the viewpoints of higher density and higher conductivity, but contains a highly insulating Ga 2 O 3 phase in the sputtering target, and the semiconductor characteristics of the thin film. Therefore, it was insufficient to ensure homogeneity and film quality stability within the sputtering target plane. Patent Document 4 is premised on an RF sputtering method that is inferior in productivity, and is difficult to apply to mass production on a large glass substrate.
　本発明は上記事情に鑑みてなされたものであり、その目的は、表示装置用酸化物半導体膜の製造に好適に用いられる酸化物焼結体およびスパッタリングターゲットであって、高い導電性と相対密度を兼ね備えた酸化物焼結体およびスパッタリングターゲットを提供することにある。 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.
　上記課題を解決し得た本発明の酸化物焼結体は、酸化亜鉛と；酸化スズと；Ａｌ、Ｈｆ、Ｔａ、Ｔｉ、Ｎｂ、Ｍｇ、Ｇａおよび希土類元素よりなる群から選択される少なくとも一種の金属（Ｍ金属）の酸化物の各粉末と、を混合および焼結して得られる酸化物焼結体であって、前記酸化物焼結体をＸ線回折したとき、Ｚｎ2ＳｎＯ4化合物は検出されるが、ＺｎＭXＯy相およびＭXＯy相（ｘ、ｙは任意の整数である）は検出されないものであるところに要旨を有するものである。 The oxide sintered body of the present invention that has solved the above problems is at least one selected from the group consisting of zinc oxide; tin oxide; Al, Hf, Ta, Ti, Nb, Mg, Ga, and rare earth elements And an oxide sintered body obtained by mixing and sintering the metal (M metal) oxide powder, and when the oxide sintered body is X-ray diffracted, a Zn 2 SnO 4 compound Is detected, but the ZnM X O y phase and M X O y phase (x and y are arbitrary integers) are not detected.
　本発明の好ましい実施形態において、前記酸化物焼結体に含まれる金属元素の含有量（原子％）をそれぞれ、［Ｚｎ］、［Ｓｎ］、［Ｍ金属］としたとき、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｚｎ］の比は、０．３５以上０．７５以下である。 In a preferred embodiment of the present invention, when the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [ The ratio of [Zn] to Sn] + [M metal] is 0.35 or more and 0.75 or less.
　本発明の好ましい実施形態において、前記酸化物焼結体に含まれる金属元素の含有量（原子％）をそれぞれ、［Ｚｎ］、［Ｓｎ］、［Ｍ金属］としたとき、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｍ金属］の比は、０．０１以上０．３０以下である。 In a preferred embodiment of the present invention, when the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [ The ratio of [M metal] to [Sn] + [M metal] is 0.01 or more and 0.30 or less.
　本発明の好ましい実施形態において、前記酸化物焼結体に含まれる金属元素の含有量（原子％）をそれぞれ、［Ｚｎ］、［Ｓｎ］、［Ｍ金属］としたとき、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｍ金属］の比は、０．０１以上０．３０以下である。 In a preferred embodiment of the present invention, when the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [ The ratio of [M metal] to [Sn] + [M metal] is 0.01 or more and 0.30 or less.
　本発明の好ましい実施形態において、前記酸化物焼結体に含まれる金属元素の含有量（原子％）をそれぞれ、［Ｚｎ］、［Ｓｎ］、［Ｍ金属］としたとき、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｍ金属］の比は、０．０１以上０．３０以下であり、且つ、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｍ金属］の比は、０．０１以上０．３０以下である。 In a preferred embodiment of the present invention, when the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [ The ratio of [M metal] to [Sn] + [M metal] is not less than 0.01 and not more than 0.30, and the ratio of [M metal] to [Zn] + [Sn] + [M metal] is It is 0.01 or more and 0.30 or less.
　本発明の好ましい実施形態において、上記のいずれかに記載の酸化物焼結体の相対密度は９０％以上であり、比抵抗は１Ωｃｍ以下である。 In a preferred embodiment of the present invention, the oxide sintered body according to any one of the above has a relative density of 90% or more and a specific resistance of 1 Ωcm or less.
　また、上記課題を解決し得た本発明のスパッタリングターゲットは、上記のいずれかに記載の酸化物焼結体を用いて得られるスパッタリングターゲットであって、相対密度９０％以上、比抵抗１Ωｃｍ以下であるところに要旨を有するものである。 Moreover, the sputtering target of the present invention that has solved the above problems is a sputtering target obtained using the oxide sintered body according to any of the above, and has a relative density of 90% or more and a specific resistance of 1 Ωcm or less. It has a gist at some point.
　本発明によれば、導電性に優れ、且つ高い相対密度を有する酸化物焼結体およびスパッタリングターゲットが得られる。また、本発明によれば、直流放電安定性に優れ、面内の均質性および膜質安定性に優れたスパッタリングターゲットが得られる。本発明のスパッタリングターゲットを用いれば、高速成膜が容易な直流スパッタリング法により酸化物半導体膜を安価に成膜できるため、生産性が向上する。 According to the present invention, an oxide sintered body and a sputtering target that are excellent in conductivity and have a high relative density can be obtained. Further, according to the present invention, a sputtering target having excellent direct current discharge stability, 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 formed at low cost by a direct current sputtering method that facilitates high-speed film formation, so that productivity is improved.
図１は、本発明の酸化物焼結体およびスパッタリングターゲットを製造するための基本的な工程を示す図である。FIG. 1 is a diagram showing a basic process for producing an oxide sintered body and a sputtering target of the present invention. 図２は、実験例１における本発明例の酸化物焼結体（Ｔａ含有ＺＴＯ、Ｔａ比＝０．０３）のＸ線回折結果を示すグラフである。FIG. 2 is a graph showing an X-ray diffraction result of the oxide sintered body (Ta-containing ZTO, Ta ratio = 0.03) of the example of the present invention in Experimental Example 1. 図３は、実験例２における本発明例の酸化物焼結体（Ａｌ含有ＺＴＯ、Ａｌ比＝０．０５）のＸ線回折結果を示すグラフである。FIG. 3 is a graph showing an X-ray diffraction result of an oxide sintered body (Al-containing ZTO, Al ratio = 0.05) of an example of the present invention in Experimental Example 2. 図４は、実験例３における本発明例の酸化物焼結体（Ｇａ含有ＺＴＯ、Ｇａ比＝０．１）のＸ線回折結果を示すグラフである。FIG. 4 is a graph showing an X-ray diffraction result of the oxide sintered body (Ga-containing ZTO, Ga ratio = 0.1) of Example of the present invention in Experimental Example 3. 図５は、実験例４における比較例の酸化物焼結体（Ａｌ含有ＺＴＯ、Ａｌ比＝０．３５）のＸ線回折結果を示すグラフである。FIG. 5 is a graph showing an X-ray diffraction result of a comparative oxide sintered body (Al-containing ZTO, Al ratio = 0.35) in Experimental Example 4.
　本発明者らは、酸化亜鉛（ＺｎＯ）と；酸化スズ（ＳｎＯ）と；Ａｌ、Ｈｆ、Ｔａ、Ｔｉ、Ｎｂ、Ｍｇ、Ｇａおよび希土類元素よりなる群から選択される少なくとも一種の金属（Ｍ金属）の酸化物（Ｍ金属酸化物）の各粉末と、を混合および焼結して得られる酸化物焼結体（以下、Ｍ金属含有ＺＴＯ系酸化物焼結体と略記する場合がある。）について、高い導電性と高い相対密度を有しており、直流スパッタリング法を適用可能なスパッタリングターゲット用酸化物焼結体を提供するため、検討を重ねてきた。その結果、上記Ｍ金属含有ＺＴＯ系酸化物焼結体をＸ線回折したとき、Ｚｎ2ＳｎＯ4化合物は検出されるが、スピネル型化合物であるＺｎＭXＯy相およびＭXＯy相（ｘ、ｙは任意の整数である）は検出されないような構成としたときに所期の目的が達成されることを見出した。 The present inventors have disclosed at least one metal (M metal) selected from the group consisting of zinc oxide (ZnO); tin oxide (SnO); Al, Hf, Ta, Ti, Nb, Mg, Ga and rare earth elements. ) Oxide oxide (M metal oxide) and an oxide sintered body obtained by mixing and sintering (hereinafter sometimes abbreviated as M metal-containing ZTO oxide sintered body). In order to provide an oxide sintered body for a sputtering target, which has high conductivity and high relative density and can be applied with a direct current sputtering method, has been studied repeatedly. As a result, when the M metal-containing ZTO-based oxide sintered body is X-ray diffracted, Zn 2 SnO 4 compound is detected, but the ZnM X O y phase and M X O y phase (x , Y is an arbitrary integer), and it was found that the intended purpose is achieved when the configuration is such that it is not detected.
　詳細には、上記Ｍ金属含有ＺＴＯ系酸化物焼結体をＸ線回折したときの相構成について、（ア）ＺｎＯとＳｎＯは、これらが結合してＺｎ2ＳｎＯ4化合物として存在し、更にＳｎＯ2とまたはＺｎＯとして存在しても良く、（イ）一方、Ｍ金属は、スピネル型化合物であるＺｎＭXＯy相およびＭXＯy相（ｘ、ｙは任意の整数である）として存在せず、Ｍ金属の全部または少なくとも一部は、Ｚｎ2ＳｎＯ4中（更に、ＳｎＯ2、ＺｎＯのいずれか一方または両方が存在するときは、Ｚｎ2ＳｎＯ4中、またはＳｎＯ2中、ＺｎＯ中のいずれか一方または両方）に固溶した状態で存在する場合に上記目的を達成し得ること、
（ウ）そして、このような相構成を有する本発明のＭ金属含有ＺＴＯ系酸化物焼結体を得るためには、所定の焼結条件（好ましくは非還元性雰囲気下にて、１３５０～１６５０℃の温度で５時間以上焼成する）を行なえば良いこと、を突き止めた。更に、直流電源によるプラズマ放電などの、直流スパッタリング法の適用を可能にするためには、（エ）上記焼結後の熱処理条件を、例えば還元性雰囲気下にて、１０００℃以上で８時間以上に制御して行なうことが好ましく、これにより、酸化物焼結体の導電性が一層向上することも見出し、本発明を完成した。 Specifically, with respect to the phase structure when the M metal-containing ZTO-based oxide sintered body is subjected to X-ray diffraction, (a) ZnO and SnO are bonded together to exist as a Zn 2 SnO 4 compound, and SnO 2 or ZnO, (b) On the other hand, M metal exists as a ZnM X O y phase and M X O y phase (x and y are arbitrary integers) which are spinel type compounds. In addition, all or at least a part of the M metal is contained in Zn 2 SnO 4 (in addition, when one or both of SnO 2 and ZnO are present, they are contained in Zn 2 SnO 4 or in SnO 2 and in ZnO. The above-mentioned purpose can be achieved when it exists in a solid solution state in either one or both),
(C) In order to obtain the M metal-containing ZTO-based oxide sintered body of the present invention having such a phase structure, 1350 to 1650 under predetermined sintering conditions (preferably in a non-reducing atmosphere). It has been found that it may be carried out at a temperature of ° C. for 5 hours or more. Furthermore, in order to make it possible to apply a direct current sputtering method such as plasma discharge with a direct current power source, (d) the heat treatment conditions after sintering are, for example, 1000 ° C. or higher and 8 hours or longer in a reducing atmosphere. It has been found that the conductivity of the oxide sintered body is further improved, and the present invention has been completed.
　まず、本発明のＭ金属含有ＺＴＯ系酸化物焼結体について詳しく説明する。上述したように本発明は、上記酸化物焼結体をＸ線回折したとき、Ｚｎ2ＳｎＯ4化合物は検出されるが、スピネル型化合物であるＺｎＭXＯy相およびＭXＯy相（ｘ、ｙは任意の整数である）は検出されないような構成の酸化物焼結体としたところに特徴がある。 First, the M metal-containing ZTO-based oxide sintered body of the present invention will be described in detail. As described above, according to the present invention, when the oxide sintered body is X-ray diffracted, a Zn 2 SnO 4 compound is detected, but a ZnM X O y phase and a M X O y phase (x , Y is an arbitrary integer), and is characterized in that it is an oxide sintered body having such a structure that it is not detected.
　本発明におけるＸ線回折条件は、以下のとおりである。
　分析装置：理学電機製「Ｘ線回折装置ＲＩＮＴ－１５００」
　分析条件
　　ターゲット：Ｃｕ
　　単色化：モノクロメートを使用（Ｋα）
　　ターゲット出力：４０ｋＶ－２００ｍＡ
　　（連続焼測定）θ／２θ走査
　　スリット：発散１／２°、散乱１／２°、受光０．１５ｍｍ
　　モノクロメータ受光スリット：０．６ｍｍ
　　走査速度：２°／ｍｉｎ
　　サンプリング幅：０．０２°
　　測定角度（２θ）：５～９０° 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 °
　次に上記Ｘ線回折によって検出される化合物、または検出されない化合物について詳しく説明する。 Next, the compound detected by the X-ray diffraction or the compound not detected will be described in detail.
　（Ｚｎ2ＳｎＯ4化合物について）
　Ｚｎ2ＳｎＯ4化合物（相）は、本発明の酸化物焼結体を構成するＺｎＯとＳｎＯ2が結合して形成されるものである。この化合物は所謂スピネル型化合物であり、電子材料として物性に富み、結晶構造の変化に伴って物性が変化するといった特徴を持つ。 (About Zn 2 SnO 4 compound)
The Zn 2 SnO 4 compound (phase) is formed by bonding ZnO and SnO 2 constituting 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.
　本発明では、Ｚｎ2ＳｎＯ4化合物（相）のほか、ＳｎＯ2やＺｎＯが若干含まれていても良い。ＺｎとＳｎの組成比によっては、Ｚｎ2ＳｎＯ4化合物だけでなくＳｎＯ2やＺｎＯが検出される場合もあるが、上記のＳｎＯ2やＺｎＯは、微量であればスパッタリングの直流放電安定性には悪影響を及ぼさないからである。例えば、２×［Ｚｎ］＝［Ｓｎ］の場合、全てのＺｎとＳｎが複合化合物を形成すれば、Ｚｎ2ＳｎＯ4化合物相のみ検出されるが、２×［Ｚｎ］＞［Ｓｎ］の場合は、上記化合物の形成に寄与しなかった微量のＺｎＯが検出され、一方、２×［Ｚｎ］＜［Ｓｎ］の場合は微量のＳｎＯ2が検出される場合がある。 In the present invention, in addition to the Zn 2 SnO 4 compound (phase), SnO 2 or ZnO may be included slightly. The composition ratio of Zn and Sn, there is a case where SnO 2 or ZnO as well Zn 2 SnO 4 compound is detected, the above SnO 2 or ZnO is a DC discharge stability of the sputtering if trace amount This is because there is no adverse effect. For example, when 2 × [Zn] = [Sn], if all Zn and Sn form a composite compound, only the Zn 2 SnO 4 compound phase is detected, but when 2 × [Zn]> [Sn] Detects a trace amount of ZnO that did not contribute to the formation of the above compound, whereas a trace amount of SnO 2 may be detected when 2 × [Zn] <[Sn].
　（ＺｎＭXＯy相およびＭXＯy相）
　ＺｎＭXＯy相およびＭXＯy相（ｘ、ｙは任意の整数である）は、本発明の酸化物焼結体を構成するＭ金属が酸素（Ｏ）と結合して形成し得るスピネル型化合物であるが、本発明では、上記のＸ線回折を行なったとき、これらの化合物が検出されないところに特徴がある。これらの化合物（例えばＴａ2Ｏ5やＡｌ2Ｏ3など）は絶縁性が高いため、Ｍ金属の酸化物が酸化物焼結体やスパッタリングターゲットに含まれていると、クラスター状に飛び出したＡｌ酸化物やＴａ酸化物が膜に混入して、薄膜の半導体特性が劣化し、キャリア移動度が低下するからである。本発明では、後記する焼結条件によって酸化物焼結体中にＭ元素の酸化物相が形成するのを防止し、Ｚｎ2ＳｎＯ4相などにＭ元素を固溶させることにより、薄膜の膜特性を安定させ、キャリア移動度の低下を防ぐことができる。 (ZnM X O y phase and M X O y phase)
The ZnM X O y phase and the M X O y phase (x and y are arbitrary integers) are spinels that can be formed by combining M metal constituting the oxide sintered body of the present invention with oxygen (O). Although it is a type compound, the present invention is characterized in that these compounds are not detected when the X-ray diffraction is performed. Since these compounds (for example, Ta 2 O 5 and Al 2 O 3 ) have high insulation properties, if an oxide of M metal is contained in an oxide sintered body or sputtering target, Al that protrudes in a cluster shape. This is because oxides and Ta oxides are mixed into the film, so that the semiconductor characteristics of the thin film are deteriorated and the carrier mobility is lowered. In the present invention, an oxide phase of M element is prevented from being formed in the oxide sintered body under the sintering conditions described later, and the M element is dissolved in the Zn 2 SnO 4 phase, etc. The characteristics can be stabilized and a decrease in carrier mobility can be prevented.
　本発明において、Ｍ金属とは後記するように、Ａｌ、Ｈｆ、Ｔａ、Ｔｉ、Ｎｂ、Ｍｇ、Ｇａおよび希土類元素よりなる群から選択される少なくとも一種の金属であり、例えばＭ金属がＡｌの場合、ＺｎＡｌ2Ｏ4やＡｌ2Ｏ3の化合物が検出されないことを意味する。なお、「検出されない」とは、上記のＸ線回折条件を行なったときに検出限界以下であることを意味する。添加されたＭ金属の全部またはその大部分は、Ｚｎ2ＳｎＯ4化合物中に固溶していることを確認している。なお、Ｚｎ2ＳｎＯ4化合物中に固溶していない残りのＭ金属は、酸化物焼結体の組成によって生成し得るＳｎＯ2やＺｎＯに固溶、もしくは粒界に偏析していると推察される。 In the present invention, M metal is at least one metal selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga and rare earth elements, as will be described later. For example, when M metal is Al , ZnAl 2 O 4 and Al 2 O 3 are not detected. “Not detected” means below the detection limit when the above-mentioned X-ray diffraction conditions are performed. It has been confirmed that all or most of the added M metal is dissolved in the Zn 2 SnO 4 compound. The remaining M metal that is not dissolved in the Zn 2 SnO 4 compound is presumed to be dissolved in SnO 2 or ZnO that can be generated by the composition of the oxide sintered body or segregated at the grain boundaries. The
　次に、本発明の酸化物焼結体を構成する元素について詳しく説明する。本発明の酸化物焼結体は、酸化亜鉛と；酸化スズと；Ａｌ、Ｈｆ、Ｔａ、Ｔｉ、Ｎｂ、Ｍｇ、Ｇａおよび希土類元素よりなる群から選択される少なくとも一種の金属（Ｍ金属）の酸化物の各粉末と、を混合および焼結して得られるものである。 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 comprises zinc oxide, tin oxide, and at least one metal (M metal) selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga, and rare earth elements. It is obtained by mixing and sintering each powder of oxide.
　このうちＺｎＯおよびＳｎＯの酸化物は、キャリア濃度を制御することによって半導体を形成する化合物であり、酸化物中の酸素含有量に応じて絶縁性から半導体、そして導電性へと性質を変化させることができる。これは、酸化物のなかに酸素欠損を故意に生じさせることによって余った電子がキャリアとなり、キャリアが比較的少数の場合は半導体に、キャリアが多量になれば縮退して導体化することが知られている。 Among these, oxides of ZnO and SnO are compounds that form a semiconductor by controlling the carrier concentration, and change the properties from insulating to semiconductor and conductive depending on the oxygen content in the oxide. Can do. 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.
　本発明に用いられるＭ金属は、スパッタリングによって形成した膜特性の向上に有用な元素であり、本発明でＺＴＯ系酸化物に適用した。Ｍ金属の添加により、例えば、キャリア移動度の向上、膜欠陥に起因すると考えられる内部準位の低減化が図られると考えられる。Ｍ金属は、Ａｌ、Ｈｆ、Ｔａ、Ｔｉ、Ｎｂ、Ｍｇ、Ｇａおよび希土類元素よりなる群から選択され、単独で用いても良いし、２種以上を併用しても良い。ここで「希土類元素」とは、ランタノイド元素（周期表において、原子番号５７のＬａから原子番号７１のＬｕまでの合計１５元素）に、Ｓｃ（スカンジウム）とＹ（イットリウム）とを加えた元素群を意味し、希土類元素は１種または２種以上を用いることができる。上記希土類元素のうち、半導体特性の観点から好ましいのはＧｄ、Ｎｄ、Ｌａ、Ｙであり、より好ましくはＬａ、Ｙである。 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 a ZTO-based oxide in the present invention. By adding M metal, it is considered that, for example, the carrier mobility is improved and the internal level, which is considered to be caused by film defects, can be reduced. The M metal is selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga and rare earth elements and may be used alone or in combination of two or more. Here, the “rare earth element” is an element group in which Sc (scandium) and Y (yttrium) are added to a lanthanoid element (a total of 15 elements from La of atomic number 57 to Lu of atomic number 71 in the periodic table). And one or more rare earth elements can be used. Among the rare earth elements, Gd, Nd, La, and Y are preferable from the viewpoint of semiconductor characteristics, and La and Y are more preferable.
　また、上記Ｍ金属全般について、半導体特性の観点などから好ましいのは、Ａｌ、Ｎｂ、Ｔｉ、Ｌａ、Ｍｇであり、より好ましくはＡｌ、Ｎｂ、Ｌａである。 Further, with respect to the above M metals in general, Al, Nb, Ti, La, and Mg are preferable from the viewpoint of semiconductor characteristics, and Al, Nb, and La are more preferable.
　本発明において、上記酸化物焼結体に含まれる金属元素の含有量（原子％）をそれぞれ、［Ｚｎ］、［Ｓｎ］、［Ｍ金属］としたとき、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｚｎ］の比[［Ｚｎ］／（［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］）、以下、Ｚｎ比と略記する場合がある。]は、０．３５以上０．７５以下であることが好ましい。上記Ｚｎ比が０．３５未満の場合、スパッタリングによって形成された薄膜の微細加工（精度良く加工すること）が難しく、エッチング残渣が生じ易い。一方、上記Ｚｎ比が０．７５を超える場合は、薄膜のキャリア移動度が低下して所望レベルの５ｃｍ2／Ｖｓを下回る。より好ましくは０．５以上０．７以下である。 In the present invention, when the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [Sn] + [ [Zn] to [M metal] ratio [[Zn] / ([Zn] + [Sn] + [M metal]), hereinafter may be abbreviated as Zn ratio. ] Is preferably 0.35 or more and 0.75 or less. When the Zn ratio is less than 0.35, fine processing (processing with high accuracy) of a thin film formed by sputtering is difficult, and etching residues are likely to occur. On the other hand, when the Zn ratio exceeds 0.75, the carrier mobility of the thin film decreases and falls below the desired level of 5 cm 2 / Vs. More preferably, it is 0.5 or more and 0.7 or less.
　また本発明において、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｍ金属］の比［［Ｍ金属］／（［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］）、以下、Ｍ金属比と略記する場合がある。］は、０．０１以上０．３０以下であることが好ましい。上記Ｍ金属比が０．０１未満の場合、添加の効果が得られない。一方、上記Ｍ金属比が０．３０を超える場合は、焼結性が悪化して製造が困難になり、直流放電安定性が不安定になる。より好ましくは０．０３以上０．１０以下である。後記する実施例では、Ｍ金属の種類に応じて、例えばＭ金属＝Ｔａの場合は、Ｔａ比と略記する場合がある。 In the present invention, the ratio of [M metal] to [Zn] + [Sn] + [M metal] [[M metal] / ([Zn] + [Sn] + [M metal]), hereinafter, the M metal ratio May be abbreviated. ] Is preferably 0.01 or more and 0.30 or less. When the M metal ratio is less than 0.01, the effect of addition cannot be obtained. On the other hand, when the M metal ratio exceeds 0.30, the sinterability deteriorates, making the production difficult, and the DC discharge stability becomes unstable. More preferably, it is 0.03 or more and 0.10 or less. In the examples described later, depending on the type of M metal, for example, when M metal = Ta, the Ta ratio may be abbreviated.
　本発明の酸化物焼結体、更には当該酸化物焼結体を用いて得られるスパッタリングターゲットは、相対密度９０％以上、比抵抗１Ωｃｍ以下であるところに特徴がある。 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 1 Ωcm or less.
　（相対密度９０％以上）
　本発明の酸化物焼結体は、相対密度が非常に高く、好ましくは９０％以上であり、より好ましくは９５％以上である。高い相対密度は、スパッタリング中での割れやノジュールの発生を防止し得るだけでなく、安定した放電をターゲットライフまで連続して維持するなどの利点をもたらす。 (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.
　なお、一般にＺＴＯ系酸化物の場合、Ｚｎ2ＳｎＯ4単相のみで構成されている方が焼結体の高密度化の観点からは好ましく、Ｍ金属酸化物粉末の添加によってＺｎＭXＯy相やＭXＯy相などが形成されてＺｎ2ＳｎＯ4以外の複数の相を形成すると相対密度の低下が生じ易くなることが知られている。これに対し本発明では、これらのＺｎＭXＯy相やＭXＯy相は含まれないため、相対密度の低下は見られず、所望レベルの９０％以上を確保することができる。また本発明の酸化物焼結体は、Ｍ金属の全部またはその大部分がＺｎ2ＳｎＯ4に固溶した単相として存在しており、多少ではあるがＺｎＯやＳｎＯ2も含み得るものであるが、このような相構成は、酸化物焼結体の緻密化を阻害するものではなく、薄膜の特性にも悪影響を及ぼすものでもない。 In general, in the case of a ZTO-based oxide, it is preferable that it is composed only of a Zn 2 SnO 4 single phase from the viewpoint of increasing the density of the sintered body, and by adding an M metal oxide powder, a ZnM X O y phase It is known that when a plurality of phases other than Zn 2 SnO 4 are formed by forming an M x O y phase or the like, the relative density tends to decrease. 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 exists as a single phase in which all or most of the M metal is dissolved in Zn 2 SnO 4 , and may contain ZnO or SnO 2 to some extent. However, such a phase structure does not hinder densification of the oxide sintered body and does not adversely affect the properties of the thin film.
　（比抵抗１Ωｃｍ以下）
　本発明の酸化物焼結体は、比抵抗が小さく、１Ωｃｍ以下であることが好ましく、より好ましくは０．１Ωｃｍ以下である。これにより、直流電源を用いたプラズマ放電などによる直流スパッタリング法による成膜が可能となり、スパッタリングターゲットを用いた物理蒸着（スパッタリング法）を表示装置の生産ラインで効率よく行うことができる。 (Specific resistance 1Ωcm or less)
The oxide sintered body of the present invention has a small specific resistance, preferably 1 Ωcm or less, more preferably 0.1 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.
　次に、本発明の酸化物焼結体を製造する方法について説明する。 Next, a method for producing the oxide sintered body of the present invention will be described.
　本発明の酸化物焼結体は、酸化亜鉛と；酸化スズと；Ａｌ、Ｈｆ、Ｔａ、Ｔｉ、Ｎｂ、Ｍｇ、Ｇａおよび希土類元素よりなる群から選択される少なくとも一種の金属（Ｍ金属）の酸化物の各粉末と、を混合および焼結して得られる酸化物焼結体であり、原料粉末からスパッタリングターゲットまでの基本工程を図１に示す。図１には、酸化物の粉末を混合・粉砕→乾燥・造粒→成形→常圧焼結→熱処理して得られた酸化物焼結体を、加工→ボンディグしてスパッタリングターゲットを得るまでの基本工程を示している。上記工程のうち本発明では、以下に詳述するように焼結条件およびその後の熱処理条件を適切に制御したところに特徴があり、それ以外の工程は特に限定されず、通常用いられる工程を適宜選択することができる。以下、各工程を説明するが、本発明はこれに限定する趣旨ではない。 The oxide sintered body of the present invention comprises zinc oxide, tin oxide, and at least one metal (M metal) selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga, and rare earth elements. FIG. 1 shows a basic process from a raw material powder to a sputtering target, which is an oxide sintered body obtained by mixing and sintering oxide powders. In FIG. 1, oxide powder is mixed and pulverized, dried and granulated, molded, subjected to atmospheric pressure sintering, heat-treated, and then the oxide sintered body is processed and bonded to obtain a sputtering target. The basic process is shown. Among the above steps, the present invention is characterized in that the sintering conditions and the subsequent heat treatment conditions are appropriately controlled as described in detail below, and the other steps are not particularly limited, and the normally used steps are appropriately selected. You can choose. Hereinafter, although each process is demonstrated, this invention is not the meaning limited to this.
　まず、酸化亜鉛粉末、酸化スズ粉末、およびＭ金属の酸化物粉末を所定の割合に配合し、混合・粉砕する。用いられる各原料粉末の純度はそれぞれ、約９９．９９％以上が好ましい。微量の不純物元素が存在すると、酸化物半導体膜の半導体特性を損なう恐れがあるためである。各原料粉末の配合割合は、ＺｎおよびＭ金属の比率が前述した範囲内となるように制御することが好ましい。 First, zinc oxide powder, tin 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.
　混合および粉砕はポットミルを使い、原料粉末を水と共に投入して行うことが好ましい。これらの工程に用いられるボールやビーズは、例えばナイロン、アルミナ、ジルコニアなどの材質のものが好ましく用いられる。 Mixing and pulverization are preferably performed by 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.
　次に、上記工程で得られた混合粉末を乾燥し造粒した後、成形する。成形に当たっては、乾燥・造粒後の粉末を所定寸法の金型に充填し、金型プレスで予備成形した後、ＣＩＰ（冷間静水圧プレス）などによって成形することが好ましい。焼結体の相対密度を上昇させるためには、予備成形の成形圧力を約０．２ｔｏｎｆ／ｃｍ2以上に制御することが好ましく、成形時の圧力は約１．２ｔｏｎｆ／ｃｍ2以上に制御することが好ましい。 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.
　次に、このようにして得られた成形体に対し、常圧にて焼成を行う。本発明では、所望の化合物相構成とし、相対密度を高めるためには、焼成温度：約１３５０℃～１６５０℃、保持時間：約５時間以上で焼結を行なうことが好ましい。焼成温度が高いほど焼結体の相対密度が向上し易く、かつ短時間で処理できるため好ましいが、温度が高くなり過ぎると焼結体が分解し易くなるため、焼成条件は上記の範囲とするのが好ましい。より好ましくは、焼成温度：約１４５０℃～１６００℃、保持時間：約８時間以上である。なお、焼成雰囲気は非還元性雰囲気が好ましく、例えば炉内に酸素ガスを導入することによって雰囲気を調整することが好ましい。 Next, the molded body thus obtained is fired at normal pressure. In the present invention, it is preferable to perform sintering at a firing temperature of about 1350 ° C. to 1650 ° C. and a holding time of about 5 hours or more in order to obtain a desired compound phase structure and increase the relative density. 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 1450 ° C. to 1600 ° 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.
　次に、焼結体に対して熱処理を行い、本発明の酸化物焼結体を得る。本発明では、直流電源によるプラズマ放電を可能にするため、熱処理温度：約１０００℃以上、保持時間：約８時間以上に制御することが好ましい。これにより、焼結体の比抵抗が、おおむね１００Ωｃｍから０．１Ωｃｍまで向上するようになる。より好ましくは、焼成温度：約１１００℃以上、保持時間：約１０時間以上である。一方、上記焼成温度が１３００℃を超えると、Ｚｎが蒸発し、成分変動が発生するため、１３００℃以下に設定することが好ましい。また、上記保持時間は、コスト低減などを考慮すると、おおむね、３０時間以下に制御することが好ましい。熱処理雰囲気は還元性雰囲気が好ましく、例えば炉内に窒素ガスを導入することによって雰囲気を調整することが好ましい。具体的には、Ｍ金属の種類などによって適切に制御することが好ましい。 Next, heat treatment is performed on the sintered body to obtain the oxide sintered body of the present invention. In the present invention, it is preferable to control the heat treatment temperature: about 1000 ° C. or more and the holding time: about 8 hours or more in order to enable plasma discharge with a DC power source. Thereby, the specific resistance of the sintered body is generally improved from 100 Ωcm to 0.1 Ωcm. More preferably, the firing temperature is about 1100 ° C. or more, and the holding time is about 10 hours or more. On the other hand, if the firing temperature exceeds 1300 ° C., Zn evaporates and component fluctuations occur, so it is preferable to set it to 1300 ° C. or lower. The holding time is preferably controlled to be approximately 30 hours or less in consideration of cost reduction and the like. The heat treatment atmosphere is preferably a reducing atmosphere. For example, it is preferable to adjust the atmosphere by introducing nitrogen gas into the furnace. Specifically, it is preferable to appropriately control depending on the type of M metal.
　上記のようにして所望の酸化物焼結体を得た後、常法により、加工→ボンディングを行なうと本発明のスパッタリングターゲットが得られる。このようにして得られるスパッタリングターゲットの相対密度および比抵抗も、酸化物焼結体と同様、非常に良好なものであり、好ましい相対密度はおおむね９０％以上であり、好ましい比抵抗はおおむね１Ωｃｍ以下である。 After obtaining the desired oxide sintered body as described above, the sputtering target of the present invention can be 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, like the oxide sintered body, and the preferable relative density is approximately 90% or more, and the preferable specific resistance is approximately 1 Ωcm or less. It is.
　以下、実施例を挙げて本発明をより具体的に説明するが、本発明は、下記実施例に限定されず、本発明の趣旨に適合し得る範囲で適切に変更を加えて実施することも可能であり、それらはいずれも本発明の技術的範囲に含まれる。 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.
　（実験例１）
　本実験例１では、Ｍ金属としてＴａを含むＴａ－ＺＴＯ焼結体（Ｔａ比＝０．０３）を以下の方法により製造した。 (Experimental example 1)
In Experimental Example 1, a Ta—ZTO sintered body (Ta ratio = 0.03) containing Ta as an M metal was manufactured by the following method.
　酸化亜鉛粉末（ＪＩＳ１種、純度９９．９９％）、純度９９．９９％の酸化スズ粉末、および純度９９．９９％の酸化タンタル粉末を［Ｚｎ］：［Ｓｎ］：［Ｔａ］＝６４．７：３２．３：３．０の比率で配合し、ナイロンボールミルで２０時間混合した。次に、上記工程で得られた混合粉末を造粒し、金型プレスにて成形圧力０．５ｔｏｎｆ／ｃｍ2で予備成形した後、ＣＩＰにて成形圧力３ｔｏｎｆ／ｃｍ2で本成形を行った。 Zinc oxide powder (JIS 1 type, purity 99.99%), tin oxide powder of purity 99.99%, and tantalum oxide powder of purity 99.99% were [Zn]: [Sn]: [Ta] = 64.7. : 32.3: 3.0 and blended with a nylon ball mill for 20 hours. Next, granulating a mixed powder obtained in the above step was preformed molding pressure 0.5tonf / cm 2 at a die press, were present molding at a molding pressure of 3tonf / cm 2 at CIP .
　このようにして得られた成形体を、常圧にて１５００℃で７時間保持して焼結を行なった。焼結炉内には酸素ガスを導入し、酸素雰囲気下で焼結した。次いで熱処理炉内に導入し、１２００℃で１０時間熱処理した。熱処理炉内には窒素ガスを導入し、還元性雰囲気で熱処理した。 The molded body thus obtained was sintered by holding at 1500 ° C. for 7 hours at normal pressure. Oxygen gas was introduced into the sintering furnace and sintered in an oxygen atmosphere. Next, it was introduced into a heat treatment furnace and heat treated at 1200 ° C. for 10 hours. Nitrogen gas was introduced into the heat treatment furnace and heat treatment was performed in a reducing atmosphere.
　このようにして得られた酸化物焼結体（Ｔａ－ＺＴＯ焼結体）を、前述した条件でＸ線回折による解析を行った結果を図２および表１に示す。図２に示すように、上記酸化物焼結体にはＺｎ2ＳｎＯ4が含まれているが、Ｔａの酸化物（Ｔａ2Ｏ5など）は検出されなかった。 FIG. 2 and Table 1 show the results of analyzing the oxide sintered body (Ta—ZTO sintered body) thus obtained by X-ray diffraction analysis under the conditions described above. As shown in FIG. 2, although the oxide sintered body contains Zn 2 SnO 4 , no Ta oxide (Ta 2 O 5 or the like) was detected.
　更に、上記の焼結体を４インチφ、５ｍｍｔの形状に加工し、バッキングプレートにボンディングしてスパッタリングターゲットを得た。このようにして得られたスパッタリングターゲットをスパッタリング装置に取り付け、ＤＣ（直流）マグネトロンスパッタリングを行なった。スパッタリング条件は、ＤＣスパッタリングパワー１５０Ｗ、Ａｒ／０．１体積％Ｏ2雰囲気、圧力０．８ｍＴｏｒｒとした。その結果、異常放電（アーキング）の発生は見られず、安定して放電することが確認された。 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.
　また、このようにして得られたスパッタリングターゲットの相対密度をアルキメデス法で測定したところ９０％以上であった。また上記スパッタリングターゲットの比抵抗を四端子法によって測定したところ、１Ωｃｍ以下であり、いずれも良好な結果が得られた。 Further, the relative density of the sputtering target thus obtained was measured by Archimedes method and found to be 90% or more. Moreover, when the specific resistance of the said sputtering target was measured by the four probe method, it was 1 ohm-cm or less, and all obtained the favorable result.
　（実験例２）
　本実験例２では、Ｍ金属としてＡｌ含むＡｌ－ＺＴＯ焼結体（Ａｌ比＝０．０５）を以下の方法により製造した。 (Experimental example 2)
In Experimental Example 2, an Al—ZTO sintered body containing Al as the M metal (Al ratio = 0.05) was produced by the following method.
　まず、前述した実験例１と同じ酸化亜鉛粉末および酸化スズ粉末と、純度９９．９９％の酸化アルミニウム粉末とを［Ｚｎ］：［Ｓｎ］：［Ａｌ］＝６３．３：３１．７：５．０の比率で配合し、成形体を１５５０℃で５時間保持して焼結した後、１１５０℃で１４時間熱処理したこと以外は、上記実験例１と同様にしてＡｌ－ＺＴＯ焼結体を得た。 First, the same zinc oxide powder and tin oxide powder as in Experimental Example 1 described above and an aluminum oxide powder with a purity of 99.99% were [Zn]: [Sn]: [Al] = 63.3: 31.7: 5. The Al—ZTO sintered body was prepared in the same manner as in Experimental Example 1 except that the mixture was blended at a ratio of 0.0 and sintered at 1550 ° C. for 5 hours and then heat-treated at 1150 ° C. for 14 hours. Obtained.
　これらの結果を図３および表１に示す。図３に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4が含まれているが、Ａｌの酸化物（Ａｌ2Ｏ3など）は検出されなかった。 These results are shown in FIG. As shown in FIG. 3, the oxide sintered body contained Zn 2 SnO 4, but no Al oxide (Al 2 O 3 or the like) was detected.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　更に上記の焼結体を、上記実験例１と同様にしてスパッタリングを行なったところ、安定して放電することが確認された。また、このようにして得られたスパッタリングターゲットの相対密度および比抵抗を、上記実験例１と同様にして測定したところ、相対密度９０％以上、比抵抗１Ωｃｍ以下であり、良好な結果が得られた。 Further, when the above sintered body was sputtered in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, when the relative density and specific resistance of the sputtering target thus obtained were measured in the same manner as in Experimental Example 1, the relative density was 90% or more and the specific resistance was 1 Ωcm or less, and good results were obtained. It was.
　（実験例３）
　本実験例３では、Ｍ金属としてＧａ含むＧａ－ＺＴＯ焼結体（Ｇａ比＝０．１）を以下の方法により製造した。 (Experimental example 3)
In Experimental Example 3, a Ga—ZTO sintered body containing Ga as an M metal (Ga ratio = 0.1) was produced by the following method.
　まず、前述した実験例１と同じ酸化亜鉛粉末および酸化スズ粉末と、純度９９．９９％の酸化ガリウム粉末を［Ｚｎ］：［Ｓｎ］：［Ｇａ］＝６０．０：３０．０：１０．０の比率で配合し、成形体を１６００℃で８時間保持して焼結した後、１２００℃で１６時間熱処理したこと以外は、上記実験例１と同様にしてＧａ－ＺＴＯ焼結体を得た。 First, the same zinc oxide powder and tin oxide powder as those of Experimental Example 1 described above and a gallium oxide powder having a purity of 99.99% were [Zn]: [Sn]: [Ga] = 60.0: 30.0: 10. A Ga—ZTO sintered body was obtained in the same manner as in Experimental Example 1 except that the mixture was blended at a ratio of 0 and sintered at 1600 ° C. for 8 hours and then heat treated at 1200 ° C. for 16 hours. It was.
　これらの結果を図４および表１に示す。図４に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4が含まれているが、Ｇａの酸化物（Ｇａ2Ｏ3など）は検出されなかった。 These results are shown in FIG. As shown in FIG. 4, the oxide sintered body contains Zn 2 SnO 4, but no Ga oxide (Ga 2 O 3 or the like) was detected.
更に上記の焼結体を、上記実験例１と同様にしてスパッタリングを行なったところ、安定して放電することが確認された。また、このようにして得られたスパッタリングターゲットの相対密度および比抵抗を、上記実験例１と同様にして測定したところ、相対密度９３％、比抵抗３．６×１０-2Ωｃｍであり、良好な結果が得られた。 Further, when the sintered body was sputtered in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, when the relative density and specific resistance of the sputtering target thus obtained were measured in the same manner as in Experimental Example 1, the relative density was 93% and the specific resistance was 3.6 × 10 −2 Ωcm, which was good. Results were obtained.
　（実験例４）
　本実験例４では、Ｍ金属としてＨｆを含むＨｆ－ＺＴＯ焼結体（Ｈｆ比＝０．０８）を以下の方法により製造した。 (Experimental example 4)
In Experimental Example 4, an Hf—ZTO sintered body (Hf ratio = 0.08) containing Hf as the M metal was manufactured by the following method.
　まず、前述した実験例１と同じ酸化亜鉛粉末および酸化スズ粉末と、純度９９．９９％の酸化ハフニウム粉末を［Ｚｎ］：［Ｓｎ］：［Ｈｆ］＝６１．３：３０．７：８．０の比率で配合し、成形体を１５００℃で７時間保持して焼結した後、１２００℃で１０時間熱処理したこと以外は、上記実験例１と同様にしてＨｆ－ＺＴＯ焼結体を得た。 First, the same zinc oxide powder and tin oxide powder as in Experimental Example 1 described above and hafnium oxide powder with a purity of 99.99% were [Zn]: [Sn]: [Hf] = 61.3: 30.7: 8. The Hf-ZTO sintered body was obtained in the same manner as in Experimental Example 1 except that the mixture was blended at a ratio of 0 and sintered at 1500 ° C. for 7 hours and then heat treated at 1200 ° C. for 10 hours. It was.
　これらの結果を表１に示す。表１に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4が含まれているが、Ｈｆの酸化物（ＨｆＯ2など）は検出されなかった。 These results are shown in Table 1. As shown in Table 1, the oxide sintered body contained Zn 2 SnO 4, but no oxide of Hf (such as HfO 2 ) was detected.
　更に上記の焼結体を、上記実験例１と同様にしてスパッタリングを行なったところ、安定して放電することが確認された。また、このようにして得られたスパッタリングターゲットの相対密度および比抵抗を、上記実験例１と同様にして測定したところ、相対密度９０％以上、比抵抗１Ωｃｍ以下であり、良好な結果が得られた。 Further, when the above sintered body was sputtered in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, when the relative density and specific resistance of the sputtering target thus obtained were measured in the same manner as in Experimental Example 1, the relative density was 90% or more and the specific resistance was 1 Ωcm or less, and good results were obtained. It was.
　（実験例５）
　本実験例５では、Ｍ金属としてＴｉを含むＴｉ－ＺＴＯ焼結体（Ｔｉ比＝０．１）を以下の方法により製造した。 (Experimental example 5)
In Experimental Example 5, a Ti—ZTO sintered body (Ti ratio = 0.1) containing Ti as an M metal was manufactured by the following method.
　まず、前述した実験例１と同じ酸化亜鉛粉末および酸化スズ粉末と、純度９９．９９％の酸化チタン粉末を［Ｚｎ］：［Ｓｎ］：［Ｔｉ］＝６０．０：３０．０：１０．０の比率で配合し、成形体を１５００℃で７時間保持して焼結した後、１２００℃で１０時間熱処理したこと以外は、上記実験例１と同様にしてＴｉ－ＺＴＯ焼結体を得た。 First, the same zinc oxide powder and tin oxide powder as those of Experimental Example 1 described above and titanium oxide powder with a purity of 99.99% were [Zn]: [Sn]: [Ti] = 60.0: 30.0: 10. A Ti—ZTO sintered body was obtained in the same manner as in Experimental Example 1 except that the mixture was blended at a ratio of 0 and sintered at 1500 ° C. for 7 hours and then heat treated at 1200 ° C. for 10 hours. It was.
　これらの結果を表１に示す。表１に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4が含まれているが、Ｔｉの酸化物（ＴｉＯ2など）は検出されなかった。 These results are shown in Table 1. As shown in Table 1, the oxide sintered body contained Zn 2 SnO 4, but no Ti oxide (TiO 2 or the like) was detected.
　更に上記の焼結体を、上記実験例１と同様にしてスパッタリングを行なったところ、安定して放電することが確認された。また、このようにして得られたスパッタリングターゲットの相対密度および比抵抗を、上記実験例１と同様にして測定したところ、相対密度９０％以上、比抵抗１Ωｃｍ以下であり、良好な結果が得られた。 Further, when the above sintered body was sputtered in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, when the relative density and specific resistance of the sputtering target thus obtained were measured in the same manner as in Experimental Example 1, the relative density was 90% or more and the specific resistance was 1 Ωcm or less, and good results were obtained. It was.
　（実験例６）
　本実験例６では、Ｍ金属としてＮｂを含むＮｂ－ＺＴＯ焼結体（Ｎｂ比＝０．０５）を以下の方法により製造した。 (Experimental example 6)
In Experimental Example 6, an Nb—ZTO sintered body (Nb ratio = 0.05) containing Nb as the M metal was manufactured by the following method.
　まず、前述した実験例１と同じ酸化亜鉛粉末および酸化スズ粉末と、純度９９．９９％の酸化ニオブ粉末を［Ｚｎ］：［Ｓｎ］：［Ｎｂ］＝６３．３：３１．７：５．０の比率で配合し、成形体を１５００℃で７時間保持して焼結した後、１２００℃で１０時間熱処理したこと以外は、上記実験例１と同様にしてＮｂ－ＺＴＯ焼結体を得た。 First, the same zinc oxide powder and tin oxide powder as in Experimental Example 1 described above and niobium oxide powder with a purity of 99.99% were [Zn]: [Sn]: [Nb] = 63.3: 31.7: 5. The Nb-ZTO sintered body was obtained in the same manner as in Experimental Example 1 except that the mixture was blended at a ratio of 0 and sintered at 1500 ° C. for 7 hours and then heat treated at 1200 ° C. for 10 hours. It was.
　これらの結果を表１に示す。表１に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4が含まれているが、Ｎｂの酸化物（Ｎｂ2Ｏ5など）は検出されなかった。 These results are shown in Table 1. As shown in Table 1, the oxide sintered body contained Zn 2 SnO 4, but Nb oxide (Nb 2 O 5 or the like) was not detected.
　更に上記の焼結体を、上記実験例１と同様にしてスパッタリングを行なったところ、安定して放電することが確認された。また、このようにして得られたスパッタリングターゲットの相対密度および比抵抗を、上記実験例１と同様にして測定したところ、相対密度９０％以上、比抵抗１Ωｃｍ以下であり、良好な結果が得られた。 Further, when the above sintered body was sputtered in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, when the relative density and specific resistance of the sputtering target thus obtained were measured in the same manner as in Experimental Example 1, the relative density was 90% or more and the specific resistance was 1 Ωcm or less, and good results were obtained. It was.
　（実験例７）
　本実験例７では、Ｍ金属としてＭｇを含むＭｇ－ＺＴＯ焼結体（Ｍｇ比＝０．０５）を以下の方法により製造した。 (Experimental example 7)
In Experimental Example 7, a Mg—ZTO sintered body (Mg ratio = 0.05) containing Mg as the M metal was manufactured by the following method.
　まず、前述した実験例１と同じ酸化亜鉛粉末および酸化スズ粉末と、純度９９．９９％の酸化マグネシウム粉末を［Ｚｎ］：［Ｓｎ］：［Ｍｇ］＝６３．３：３１．７：５．０の比率で配合し、成形体を１５００℃で７時間保持して焼結した後、１５００℃で１０時間熱処理したこと以外は、上記実験例１と同様にしてＭｇ－ＺＴＯ焼結体を得た。 First, the same zinc oxide powder and tin oxide powder as in Experimental Example 1 described above and a magnesium oxide powder with a purity of 99.99% [Zn]: [Sn]: [Mg] = 63.3: 31.7: 5. An Mg—ZTO sintered body was obtained in the same manner as in Experimental Example 1 except that the mixture was blended at a ratio of 0 and sintered at 1500 ° C. for 7 hours and sintered and then heat-treated at 1500 ° C. for 10 hours. It was.
　これらの結果を表１に示す。表１に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4が含まれているが、Ｍｇの酸化物（ＭｇＯなど）は検出されなかった。 These results are shown in Table 1. As shown in Table 1, the oxide sintered body contained Zn 2 SnO 4, but no Mg oxide (such as MgO) was detected.
　更に上記の焼結体を、上記実験例１と同様にしてスパッタリングを行なったところ、安定して放電することが確認された。また、このようにして得られたスパッタリングターゲットの相対密度および比抵抗を、上記実験例１と同様にして測定したところ、相対密度９０％以上、比抵抗１Ωｃｍ以下であり、良好な結果が得られた。 Further, when the above sintered body was sputtered in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, when the relative density and specific resistance of the sputtering target thus obtained were measured in the same manner as in Experimental Example 1, the relative density was 90% or more and the specific resistance was 1 Ωcm or less, and good results were obtained. It was.
　（実験例８）
　本実験例８では、Ｍ金属としてＧａを含むＧａ－ＺＴＯ焼結体（Ｇａ比＝０．２０）を以下の方法により製造した。 (Experimental example 8)
In Experimental Example 8, a Ga—ZTO sintered body (Ga ratio = 0.20) containing Ga as an M metal was manufactured by the following method.
　まず、前述した実験例１と同じ酸化亜鉛粉末および酸化スズ粉末と、純度９９．９９％の酸化ガリウム粉末を［Ｚｎ］：［Ｓｎ］：［Ｇａ］＝４０．０：４０．０：２０．０の比率で配合し、成形体を１５００℃で７時間保持して焼結した後、１５００℃で１０時間熱処理したこと以外は、上記実験例１と同様にしてＧａ－ＺＴＯ焼結体を得た。 First, the same zinc oxide powder and tin oxide powder as those of Experimental Example 1 described above and a gallium oxide powder having a purity of 99.99% [Zn]: [Sn]: [Ga] = 40.0: 40.0: 20. A Ga—ZTO sintered body was obtained in the same manner as in Experimental Example 1 except that the mixture was blended at a ratio of 0 and sintered at 1500 ° C. for 7 hours and then heat treated at 1500 ° C. for 10 hours. It was.
　これらの結果を表１に示す。表１に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4が含まれているが、Ｇａの酸化物（Ｇａ2Ｏ3など）は検出されなかった。 These results are shown in Table 1. As shown in Table 1, the oxide sintered body contained Zn 2 SnO 4, but no Ga oxide (Ga 2 O 3 or the like) was detected.
　（実験例９）
　本実験例９では、Ｍ金属としてＬａを含むＬａ－ＺＴＯ焼結体（Ｌａ比＝０．０５）を以下の方法により製造した。 (Experimental example 9)
In Experimental Example 9, a La—ZTO sintered body containing La as an M metal (La ratio = 0.05) was produced by the following method.
　まず、前述した実験例１と同じ酸化亜鉛粉末および酸化スズ粉末と、純度９９．９９％の酸化ランタン粉末を［Ｚｎ］：［Ｓｎ］：［Ｌａ］＝６３．３：３１．７：５．０の比率で配合し、成形体を１５００℃で７時間保持して焼結した後、１５００℃で１０時間熱処理したこと以外は、上記実験例１と同様にしてＬａ－ＺＴＯ焼結体を得た。 First, the same zinc oxide powder and tin oxide powder as those of Experimental Example 1 described above and a lanthanum oxide powder having a purity of 99.99% were [Zn]: [Sn]: [La] = 63.3: 31.7: 5. A La-ZTO sintered body was obtained in the same manner as in Experimental Example 1 except that the mixture was blended at a ratio of 0 and sintered at 1500 ° C. for 7 hours and then heat-treated at 1500 ° C. for 10 hours. It was.
　これらの結果を表１に示す。表１に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4が含まれているが、Ｌａの酸化物（Ｌａ2Ｏ3など）は検出されなかった。 These results are shown in Table 1. As shown in Table 1, the oxide sintered body contained Zn 2 SnO 4, but no La oxide (such as La 2 O 3 ) was detected.
　（比較例１）
　本比較例１では、Ｍ金属としてＡｌ含むＡｌ－ＺＴＯ焼結体（Ａｌ比＝０．３５）を以下の方法により製造した。 (Comparative Example 1)
In this comparative example 1, an Al—ZTO sintered body (Al ratio = 0.35) containing Al as M metal was produced by the following method.
　まず、前述した実験例２と同じ酸化亜鉛粉末と酸化スズ粉末と酸化アルミニウム粉末とを、［Ｚｎ］：［Ｓｎ］：［Ａｌ］＝４３．３：２１．７：３５．０の比率で配合し、炉ＺｎＭXＯy相およびＭXＯy相を内に成形体を１３００℃で５時間保持して焼結し、１２００℃で１０時間熱処理したこと以外は、上記実験例１と同様にしてＡｌ－ＺＴＯ焼結体を得た。 First, the same zinc oxide powder, tin oxide powder and aluminum oxide powder as those of Experimental Example 2 described above were blended at a ratio of [Zn]: [Sn]: [Al] = 43.3: 21.7: 35.0. Then, in the same manner as in Experimental Example 1 except that the molded body was sintered at 1300 ° C. for 5 hours and heat treated at 1200 ° C. for 10 hours with the furnace ZnM X O y phase and M X O y phase inside. Thus, an Al—ZTO sintered body was obtained.
　これらの結果を図５に示す。図５に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4とＺｎＯのほかに、Ａｌの酸化物であるＺｎＡｌ2Ｏ4が検出された。 These results are shown in FIG. As shown in FIG. 5, ZnAl 2 O 4 that is an oxide of Al was detected in the oxide sintered body in addition to Zn 2 SnO 4 and ZnO.
　更に上記の焼結体を、上記実験例１と同様にしてスパッタリングを行なったところ、スパッタリング中に異常放電が発生した。また、このようにして得られたスパッタリングターゲットの相対密度および比抵抗を、上記実験例１と同様にして測定したところ、相対密度は６７％と低く、比抵抗は１００Ωｃｍであった。 Further, when the sintered body was sputtered in the same manner as in Experimental Example 1, abnormal discharge occurred during sputtering. Moreover, when the relative density and specific resistance of the sputtering target thus obtained were measured in the same manner as in Experimental Example 1, the relative density was as low as 67% and the specific resistance was 100 Ωcm.
　（参考例）
　本参考例では、Ｍ金属を含まないＺＴＯ焼結体を以下の方法により製造した。 (Reference example)
In this reference example, a ZTO sintered body containing no M metal was produced by the following method.
　まず、前述した実験例１と同じ酸化亜鉛粉末および酸化スズ粉末を、［Ｚｎ］：［Ｓｎ］＝６６．７：３３．３の比率で配合し、成形体を１５００℃で７時間保持して焼結した後、１２００℃で１０時間熱処理したこと以外は、上記実験例１と同様にしてＺＴＯ焼結体を得た。 First, the same zinc oxide powder and tin oxide powder as those of Experimental Example 1 described above were blended at a ratio of [Zn]: [Sn] = 66.7: 33.3, and the compact was held at 1500 ° C. for 7 hours. After sintering, a ZTO sintered body was obtained in the same manner as in Experimental Example 1 except that heat treatment was performed at 1200 ° C. for 10 hours.
　これらの結果を表１に示す。表１に示すように、上記酸化物焼結体には、Ｚｎ2ＳｎＯ4が含まれていた。上記参考例ではＭ金属を添加していないため、表１中、「Ｍ金属酸化物」、「ＺｎＭXＯy」および「ＭXＯy相」の欄は「－（なし）」となる。 These results are shown in Table 1. As shown in Table 1, the oxide sintered body contained Zn 2 SnO 4 . In the above reference example, since M metal is not added, the columns of “M metal oxide”, “ZnM X O y ”, and “M X O y phase” in Table 1 are “-(none)”.
　更に上記の焼結体を、上記実験例１と同様にしてスパッタリングを行なったところ、安定して放電することが確認された。また、このようにして得られたスパッタリングターゲットの相対密度および比抵抗を、上記実験例１と同様にして測定したところ、相対密度９０％以上、比抵抗１Ωｃｍ以下であり、良好な結果が得られた。 Further, when the above sintered body was sputtered in the same manner as in Experimental Example 1, it was confirmed that the discharge was stably performed. Moreover, when the relative density and specific resistance of the sputtering target thus obtained were measured in the same manner as in Experimental Example 1, the relative density was 90% or more and the specific resistance was 1 Ωcm or less, and good results were obtained. It was.
　以上の実験結果より、本発明に用いられるＭ金属を含むＺＴＯ系酸化物焼結体は、Ｘ線回折の結果、Ｍ金属の酸化物であるＺｎＭXＯy相およびＭXＯy相を分離形成しないことが確認された。その結果、本発明の酸化物焼結体および当該焼結体を用いて得られるスパッタリングターゲットは、高い相対密度および低い比抵抗を有しており、極めて良好な特性を有することが分かった。 From the above experimental results, the ZTO 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 did not form. 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 (6)

  1. 　酸化亜鉛と；酸化スズと；Ａｌ、Ｈｆ、Ｔａ、Ｔｉ、Ｎｂ、Ｍｇ、Ｇａおよび希土類元素よりなる群から選択される少なくとも一種の金属（Ｍ金属）の酸化物の各粉末と、を混合および焼結して得られる酸化物焼結体であって、
    　前記酸化物焼結体をＸ線回折したとき、Ｚｎ2ＳｎＯ4化合物は検出されるが、ＺｎＭXＯy相およびＭXＯy相（ｘ、ｙは任意の整数である）は検出されないものであることを特徴とする酸化物焼結体。     Zinc oxide; tin oxide; and powders of oxides of at least one metal (M metal) selected from the group consisting of Al, Hf, Ta, Ti, Nb, Mg, Ga and rare earth elements and An oxide sintered body obtained by sintering,
    When the oxide sintered body is subjected to X-ray diffraction, Zn 2 SnO 4 compound is detected, but ZnM X O y phase and M X O y phase (x and y are arbitrary integers) are not detected An oxide sintered body characterized by being:
  2. 　前記酸化物焼結体に含まれる金属元素の含有量（原子％）をそれぞれ、［Ｚｎ］、［Ｓｎ］、［Ｍ金属］としたとき、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｚｎ］の比は、０．３５以上０．７５以下である請求項１に記載の酸化物焼結体。 When the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [Sn] + [M metal] 2. The oxide sintered body according to claim 1, wherein a ratio of [Zn] is 0.35 or more and 0.75 or less.
  3. 　前記酸化物焼結体に含まれる金属元素の含有量（原子％）をそれぞれ、［Ｚｎ］、［Ｓｎ］、［Ｍ金属］としたとき、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｍ金属］の比は、０．０１以上０．３０以下である請求項１に記載の酸化物焼結体。 When the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [Sn] + [M metal] 2. The oxide sintered body according to claim 1, wherein a ratio of [M metal] is 0.01 or more and 0.30 or less.
  4. 　前記酸化物焼結体に含まれる金属元素の含有量（原子％）をそれぞれ、［Ｚｎ］、［Ｓｎ］、［Ｍ金属］としたとき、［Ｚｎ］＋［Ｓｎ］＋［Ｍ金属］に対する［Ｍ金属］の比は、０．０１以上０．３０以下である請求項２に記載の酸化物焼結体。 When the content (atomic%) of the metal element contained in the oxide sintered body is [Zn], [Sn], and [M metal], respectively, [Zn] + [Sn] + [M metal] The oxide sintered body according to claim 2, wherein the ratio of [M metal] is 0.01 or more and 0.30 or less.
  5. 　相対密度９０％以上、比抵抗１Ωｃｍ以下である請求項１～４のいずれかに記載の酸化物焼結体。 The oxide sintered body according to any one of claims 1 to 4, which has a relative density of 90% or more and a specific resistance of 1 Ωcm or less.
  6. 　請求項１～４のいずれかに記載の酸化物焼結体を用いて得られるスパッタリングターゲットであって、相対密度９０％以上、比抵抗１Ωｃｍ以下であることを特徴とするスパッタリングターゲット。
     
          A sputtering target obtained by using the oxide sintered body according to any one of claims 1 to 4, wherein the relative density is 90% or more and the specific resistance is 1 Ωcm or less.

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