WO2020241227A1 - Oxide sintered body and sputtering target - Google Patents

Oxide sintered body and sputtering target Download PDF

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WO2020241227A1
WO2020241227A1 PCT/JP2020/018873 JP2020018873W WO2020241227A1 WO 2020241227 A1 WO2020241227 A1 WO 2020241227A1 JP 2020018873 W JP2020018873 W JP 2020018873W WO 2020241227 A1 WO2020241227 A1 WO 2020241227A1
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oxide
crystal grains
sintered body
znin
crystal
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PCT/JP2020/018873
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French (fr)
Japanese (ja)
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浩一 宮田
達昭 篠田
幸樹 田尾
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株式会社コベルコ科研
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • 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
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • 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
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • 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

Definitions

  • the present invention relates to an oxide sintered body and a sputtering target.
  • Amorphous oxide semiconductors have higher carrier mobility when thin film transistors (TFTs) are formed than, for example, amorphous silicon semiconductors.
  • amorphous oxide semiconductors have a large optical bandgap and high visible light transmission.
  • the thin film of the amorphous oxide semiconductor can be formed at a lower temperature than the amorphous silicon semiconductor. Taking advantage of these characteristics, the thin film of amorphous oxide semiconductor can be applied to next-generation large displays that can be driven at high speed with high resolution and flexible displays that use resin substrates that require film formation at low temperatures. It is expected.
  • an amorphous oxide semiconductor containing indium As the amorphous oxide semiconductor, an amorphous oxide semiconductor containing indium has been proposed, and an In-Ga-Zn-O (IGZO) amorphous oxide semiconductor containing indium, gallium, zinc and oxygen, indium and gallium.
  • In-Ga-Zn-Sn-O (IGZTO) amorphous oxide semiconductors containing zinc, tin and oxygen are attracting attention.
  • the thin film of the amorphous oxide semiconductor is formed by a sputtering method using a sputtering target having the same composition as this amorphous oxide semiconductor.
  • this sputtering method if an abnormal discharge occurs during sputtering, the sputtering target may crack. Therefore, in order to suppress cracking of the sputtering target, it has been studied to adjust the content of the crystal phase in the sputtering target (see JP-A-2014-58415).
  • the present invention has been made based on such circumstances, and an object of the present invention is to provide an oxide sintered body and a sputtering target capable of suppressing the occurrence of cracks.
  • the oxide sintered body according to one aspect of the present invention made to solve the above problems is an oxide sintered body containing In, Zn and Fe, and substantially contains crystal grains of zinc oxide (ZnO). In 2 O 3 crystal single-phase structure having In oxide crystal grains and ZnIn oxide crystal grains, and the In oxide crystal grains substantially containing no Fe, as described above.
  • the grains of ZnIn oxide contain Fe.
  • the oxide sintered body can be obtained so as to have substantially no zinc oxide crystal grains and having ZnIn oxide crystal grains.
  • the oxide sintered body has substantially no zinc oxide crystal grains, has In oxide crystal grains and ZnIn oxide crystal grains, and the In oxide crystal grains substantially contain Fe.
  • the occurrence of cracks can be suppressed by having an In 2 O 3 crystal single-phase structure that does not contain the target.
  • the crystal grains of the ZnIn oxide do not have a Zn 2 In 2 O 5 crystal single-phase structure.
  • the strength can be easily increased.
  • the occurrence of cracks can be suppressed more reliably.
  • the crystal grains of the ZnIn oxide have at least one of the crystal structures of Zn 3 In 2 O 6 , Zn 4 In 2 O 7, and Zn 5 In 2 O 8 .
  • the crystal grains of the ZnIn oxide have at least one of the crystal structures of Zn 3 In 2 O 6 , Zn 4 In 2 O 7, and Zn 5 In 2 O 8 to increase the bulk resistance. It is easy to increase the strength while suppressing it.
  • the oxide sintered body does not have substantially no crystal grains of ZnInFe oxide. As a result, it is possible to easily obtain the above-mentioned configuration having substantially no zinc oxide crystal grains and having ZnIn oxide crystal grains while suppressing the Fe content ratio.
  • the oxide sintered body has an In atom number of 45 atm% or more and 80 atm% or less, a Zn atom number of 20 atm% or more and 55 atm% or less, and an Fe atom number of 0 with respect to the total atomic number of In, Zn and Fe. It is preferable that it is 1 atm% or more and 1.5 atm% or less. As a result, it is easy to increase the strength while suppressing the bulk resistance. As a result, the occurrence of cracks can be suppressed more reliably.
  • the bulk resistance of the oxide sintered body is preferably 1 ⁇ 10 -2 ⁇ cm or less. As described above, when the bulk resistance is not more than the above upper limit, the destabilization of the discharge during sputtering can be suppressed, and the occurrence of cracks in the oxide sintered body due to the abnormal discharge is sufficiently suppressed. be able to.
  • the relative density of the oxide sintered body is preferably 96% or more. As described above, when the relative density is at least the above lower limit, the occurrence of cracks can be sufficiently suppressed by increasing the strength.
  • the sputtering target according to another aspect of the present invention made to solve the above problems is a sputtering target containing In, Zn and Fe, and has substantially no crystal grains of zinc oxide (ZnO). , and a grain of the crystal grains and ZnIn oxides of in oxide, the crystal grains of the in oxide is in 2 O 3 crystal single phase structure is substantially free of Fe, the ZnIn oxide The crystal grains contain Fe.
  • the sputtering target can suppress the occurrence of cracks.
  • the "crystal grain” refers to a region surrounded by grain boundary phases in a reflected electron image observed at a magnification of 1000 by a scanning electron microscope (SEM).
  • crystal grains contain Fe means that Fe is detected in the crystal grains at 0.1 atm% or more when elemental analysis of the crystal grains is performed by energy dispersive X-ray spectroscopy (EDX). That is, “the crystal grains do not substantially contain Fe” means that Fe is not detected in the crystal grains in an amount of 0.1 atm% or more.
  • “Substantially free of crystal grains” means that the region surrounded by the grain boundary phase is not visible in the reflected electron image observed at 1000 times by a scanning electron microscope (SEM).
  • “Bulk resistance” refers to the volumetric resistance measured by the 4-probe method.
  • the “relative density” means a value calculated by (measured density / true density) x 100 [%].
  • the "measured density” means a value obtained by the Archimedes method.
  • the oxide sintered body and the sputtering target according to the present invention can suppress the occurrence of cracks.
  • FIG. 1 is a schematic cross-sectional view showing an oxide sintered body according to an embodiment of the present invention.
  • FIG. 2 shows No. It is a reflected electron image of the oxide sintered body of 3.
  • FIG. 3 shows No. It is a reflected electron image of the oxide sintered body of 4.
  • FIG. 4 shows No. It is a reflected electron image of the oxide sintered body of 5.
  • FIG. 5 shows No. It is a reflected electron image of the oxide sintered body of 6.
  • FIG. 6 shows No. It is a reflected electron image of the oxide sintered body of 7.
  • FIG. 7 shows No. It is a reflected electron image of the oxide sintered body of 1.
  • FIG. 8 shows No. 9 is a backscattered electron image of the oxide sintered body of 9.
  • FIG. 9 shows No.
  • FIG. 10 shows No. It is a reflected electron image of 12 oxide sintered bodies.
  • FIG. 11 shows No. It is an analysis result of the X-ray diffraction spectrum of the oxide sintered body of 9.
  • FIG. 12 shows No. It is an analysis result of the X-ray diffraction spectrum of 10 oxide sintered bodies.
  • FIG. 13 shows No. It is the analysis result of the X-ray diffraction spectrum of the oxide sintered body of 13.
  • FIG. 14 shows No. It is the analysis result of the X-ray diffraction spectrum of 14 oxide sintered bodies.
  • the oxide sintered body 1 of FIG. 1 contains In (indium), Zn (zinc) and Fe (iron).
  • the oxide sintered body 1 has In oxide crystal grains and ZnIn oxide crystal grains.
  • the oxide sintered body 1 has substantially no zinc oxide crystal grains (that is, has substantially no oxide crystal grains that do not substantially contain metal elements other than Zn).
  • the crystal grains of the ZnIn oxide contain Fe.
  • the crystal grains of the In oxide have an In 2 O 3 crystal single-phase structure that does not substantially contain Fe.
  • the crystal structure of the In oxide crystal grains and the crystal structure of the ZnIn oxide crystal grains can be obtained by analyzing the X-ray diffraction spectrum of each crystal grain.
  • the oxide sintered body 1 may contain In, Zn and Fe and unavoidable impurities as metal elements. In other words, it is preferable that the oxide sintered body 1 does not substantially contain metal elements other than In, Zn and Fe.
  • the oxide sintered body 1 is used, for example, as a sputtering target capable of forming a thin film of an amorphous oxide semiconductor. In contributes to the improvement of carrier mobility of the thin film. Further, Zn contributes to the stabilization of the amorphous structure of the thin film.
  • the oxide sintered body 1 has ZnIn oxide crystal grains that substantially do not contain metal elements other than Zn and In, and Fe is contained in the crystal structure of the ZnIn oxide crystal grains. Is solidly dissolved.
  • Fe is dissolved in the crystal structure of the crystal grains of ZnIn oxide, and by adding a small amount of Fe, a compound of zinc oxide and In oxide (specifically, The growth of the ZnIn oxide, which is a compound of In 2 O 3 and Zn O), can be significantly promoted. That is, the oxide sintered body 1 can eliminate the crystal grains of zinc oxide and significantly increase the volume fraction of the ZnIn oxide by adding a small amount of Fe. As a result, it is considered that the oxide sintered body 1 can easily improve the uniform dispersibility of Zn.
  • the crystal grains of the ZnIn oxide do not have a Zn 2 In 2 O 5 crystal single-phase structure.
  • the proportion of Zn 2 In 2 O 5 as the crystal grains of the Zn In oxide increases.
  • the crystal grains of the ZnIn oxide have a Zn 2 In 2 O 5 crystal single-phase structure, the pore area in the crystal becomes large, and minute cracks are likely to be formed.
  • the crystal grains of the ZnIn oxide do not have a Zn 2 In 2 O 5 crystal single-phase structure, so that the strength is increased and the occurrence of cracks is more reliably suppressed. Can be done.
  • the amount of Fe added can be suppressed and the bulk resistance can be easily controlled to be small.
  • the crystal grains of the ZnIn oxide have at least one of the crystal structures of Zn 3 In 2 O 6 , Zn 4 In 2 O 7, and Zn 5 In 2 O 8 .
  • the oxide sintered body 1 tends to suppress bulk resistance and increase its strength.
  • the crystal grains of the ZnIn oxide do not have the crystal structure of Zn 2 In 2 O 5 .
  • the oxide sintered body 1 does not substantially have crystal grains of ZnInFe oxide.
  • the above-mentioned configuration can be easily obtained in the oxide sintered body 1 having substantially no zinc oxide crystal grains and having ZnIn oxide crystal grains while suppressing the Fe content ratio. .. That is, as described above, the oxide sintered body 1 selectively dissolves Fe in the crystal structure of the crystal grains of ZnIn oxide, thereby suppressing the content ratio of Fe and the zinc oxide crystal. It is possible to eliminate grains and efficiently grow ZnIn oxide crystal grains.
  • the upper limit of the number of atoms is preferably 80 atm%, more preferably 75 atm%, and even more preferably 70 atm%. If the number of atoms is less than the above lower limit, the carrier mobility of the thin film of the amorphous oxide semiconductor formed by using the oxide sintered body 1 may be insufficient. On the contrary, when the number of atoms exceeds the upper limit, the leak current of the thin film increases or the threshold voltage shifts to the negative side, so that the thin film may become a conductor.
  • the lower limit of the number of atoms of Zn with respect to the total number of atoms of In, Zn and Fe 20 atm% is preferable, 25 atm% is more preferable, and 30 atm% is further preferable.
  • the upper limit of the number of atoms 55 atm% is preferable, and 50 atm% is more preferable. If the number of atoms is less than the above lower limit, the number of other metal atoms becomes relatively large, which may cause the thin film to become a conductor. On the contrary, when the number of atoms exceeds the above upper limit, the carrier concentration may be suppressed and the carrier mobility of the thin film may be insufficient.
  • the lower limit of the number of atoms of Fe with respect to the total number of atoms of In, Zn and Fe 0.1 atm% is preferable, and 0.3 atm% is more preferable.
  • the upper limit of the number of atoms is preferably 1.5 atm%, more preferably 1.0 atm%. If the number of atoms is less than the above lower limit, the growth of ZnIn oxide crystal grains may not be sufficiently promoted. On the other hand, if the number of atoms exceeds the above upper limit, the bulk resistance of the oxide sintered body 1 may increase, or the relative density of the oxide sintered body 1 may become insufficient.
  • the oxide sintered body 1 has an In atom number of 45 atm% or more and 80 atm% or less, a Zn atom number of 20 atm% or more and 55 atm% or less, and a Fe atom number with respect to the total atomic number of In, Zn and Fe. It is preferably 0.1 atm% or more and 1.5 atm% or less, the number of In atoms is 50 atm% or more and 70 atm% or less, the number of Zn atoms is 30 atm% or more and 50 atm% or less, and the number of Fe atoms is 0.1 atm% or more. It is more preferably 1.0 atom% or less. By adjusting the number of atoms of In, Zn and Fe within the above range, the oxide sintered body 1 can easily increase its strength while suppressing the bulk resistance. As a result, the occurrence of cracks can be suppressed more reliably.
  • the upper limit of the bulk resistance of the oxide sintered body 1 1 ⁇ 10 ⁇ 2 ⁇ cm is preferable, 5 ⁇ 10 -3 ⁇ cm is more preferable, and 4 ⁇ 10 -3 ⁇ cm is further preferable. If the bulk resistance exceeds the upper limit, the discharge may become unstable during sputtering, and the oxide sintered body 1 may be cracked due to the abnormal discharge.
  • the lower limit of the bulk resistance is not particularly limited, but may be, for example, 1 ⁇ 10 -4 ⁇ cm.
  • the lower limit of the relative density of the oxide sintered body 1 is preferably 96%, more preferably 97%. If the relative density does not reach the lower limit, the strength becomes insufficient and cracks may occur.
  • the relative density is preferably large, and the upper limit thereof can be, for example, 100%.
  • the oxide sintered body 1 can be easily obtained to have a structure in which it has substantially no zinc oxide crystal grains and has ZnIn oxide crystal grains. ..
  • the oxide sintered body 1 has substantially no zinc oxide crystal grains, has In oxide crystal grains and ZnIn oxide crystal grains, and the In oxide crystal grains contain Fe.
  • the occurrence of cracks can be suppressed by having an In 2 O 3 crystal single-phase structure that is substantially free of.
  • the sputtering target is a sputtering target containing In, Zn, and Fe, which has substantially no zinc oxide crystal grains and has In oxide crystal grains and ZnIn oxide crystal grains.
  • the crystal grains of the In oxide have an In 2 O 3 crystal single-phase structure that does not substantially contain Fe, and the crystal grains of the ZnIn oxide contain Fe.
  • the sputtering target has the oxide sintered body 1 of FIG.
  • the specific configuration of the sputtering target is the same as that of the oxide sintered body 1.
  • the sputtering target can suppress the occurrence of cracks in the same manner as the oxide sintered body 1.
  • the oxide sintered body and the sputtering target may contain, for example, Sn (tin) as another metal element.
  • Zinc oxide powder with a purity of 99.99% (ZnO), indium oxide powder with a purity of 99.99% (In 2 O 3 ), and iron oxide powder with a purity of 99.4% (Fe 2 O 3 ) are shown in Table 1.
  • Raw material powder was obtained by blending in several ratios. Water was added to this raw material powder, and the mixture was mixed and pulverized for 18 hours in a ball mill using a nylon pod and zirconia balls as a medium. Next, the obtained mixed powder was dried and granulated. The mixed powder after granulation was set in a graphite mold and hot-pressed under the conditions shown in Table 1. In this hot press, N 2 gas was introduced into the furnace and sintered in an N 2 atmosphere.
  • the X-ray diffraction spectrum of the obtained oxide sintered body was analyzed, and the crystal structure and content ratio of the crystal grains of In oxide, zinc oxide and ZnIn oxide were determined. The results are shown in Table 2.
  • ZnIn oxide Zn 5 In 2 O 8
  • Zn 5 In 2 O 8 is a compound of In 2 O 3 and Zn O
  • the atoms shown in Table 3 are zinc oxide powder (ZnO) with a purity of 99.99%, indium oxide powder with a purity of 99.99% (In 2 O 3 ), and iron oxide powder with a purity of 99.4% (Fe 2 O 3 ).
  • Raw material powder was obtained by blending in several ratios. Water, a binder containing polyvinyl alcohol as a main component, and a dispersant containing an acrylic polymer as a main component were added, and the mixture was mixed and pulverized in a ball mill using a nylon pod and zirconia balls as a medium for 3 hours. Next, the obtained mixed powder was dried and granulated.
  • the mixed powder after granulation was placed in a molding die and pressed at 3 ton / cm 2 with a cold hydrostatic press to obtain a molded product.
  • This molded product was heated to 1550 ° C. under normal pressure and atmospheric atmosphere, held for 2 hours, naturally lowered to a temperature, and sintered. 3 to No.
  • An oxide sintered body of 8 was obtained.
  • No. 3 to No. The reflected electron images of No. 7 observed at 1000 times by a scanning electron microscope (SEM) are shown in FIGS. 2 to 6.
  • No. 3 to No. 7 The X-ray diffraction spectrum of No. 8 was analyzed to determine the crystal structure of the crystal grains of In oxide, zinc oxide and ZnIn oxide. As shown in FIGS. 2 to 6, No. 3 to No. 7 has In oxide crystal grains (In 2 O 3 crystal single-phase structure) X and Zn In oxide crystal grains Y, but does not substantially have zinc oxide crystal grains. Further, as a result of the analysis of the X-ray diffraction spectrum, the amount of Fe added was 0.9 atm% or less. 3, No. 4 and No. In No. 7, the crystal grains of ZnIn oxide had a crystal single-phase structure of Zn 3 In 2 O 6 , whereas the amount of Fe added was increased to 1.5 atm%.
  • the crystal grains of the ZnIn oxide have Zn 3 In 2 O 6 and Zn 2 In 2 O 5, and a striped structure appears in Zn 3 In 2 O 6 .
  • the striped structure has disappeared, and the crystal grains of the ZnIn oxide have a crystal single-phase structure of Zn 2 In 2 O 5 .
  • the relative density of the oxide sintered body decreases as the amount of Fe added increases, and when the amount of Fe added reaches 5.0 atm%, the relative density decreases to about 87%. There is.
  • the bulk resistance can be controlled to 3.7 ⁇ 10 -3 ⁇ cm or less, but the amount of Fe added is 5.0 atm. When it increases to%, the bulk resistance increases to 8 ⁇ 10 -3 or more and becomes unstable.
  • Zinc oxide powder (ZnO) with a purity of 99.99%, indium oxide powder with a purity of 99.99% (In 2 O 3 ), and iron oxide powder with a purity of 99.4% (Fe 2 O 3 ) are shown in Table 6.
  • Raw material powder was obtained by blending in several ratios. Water, a binder containing polyvinyl alcohol as a main component, and a dispersant containing an acrylic polymer as a main component were added, and the mixture was mixed and pulverized with a nylon pod and a ball mill using zirconia balls as a medium for 3 hours. Next, the obtained mixed powder was dried and granulated.
  • the mixed powder after granulation was placed in a molding die and pressed at 3 ton / cm 2 with a cold hydrostatic press to obtain a molded product.
  • This molded product was heated to 1550 ° C. under normal pressure and atmospheric atmosphere, held for 2 hours, naturally lowered to a temperature, and sintered. 9-No. 14 oxide sintered bodies were obtained. No. 9, No. 10 and No.
  • the reflected electron images of No. 12 observed by a scanning electron microscope (SEM) at a magnification of 5000 are shown in FIGS. 8 to 10.
  • No. No. 9 was composed of three phases of In 2 O 3 crystal grains, Zn 3 In 2 O 6 crystal grains, and Zn 2 In 2 O 5 crystal grains, and it was confirmed that Zn O crystal grains did not exist.
  • No. No. 10 was composed of two phases of In 2 O 3 crystal grains and Zn 3 In 2 O 6 crystal grains, and it was confirmed that Zn O crystal grains did not exist.
  • the ratio of the number of Zn atoms (Zn / In) to the number of In atoms is as small as 0.10.
  • FIG. 13 in No.
  • the oxide sintered body according to one aspect of the present invention can suppress the occurrence of cracks, and is therefore preferably used as a sputtering target.

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Abstract

The present invention addresses the problem of providing an oxide sintered body which can be prevented from the occurrence of cracking. The oxide sintered body according to one embodiment of the present invention is an oxide sintered body containing In, Zn and Fe, does not contain zinc oxide crystal grains substantially, and contains In oxide crystal grains and ZnIn oxide crystal grains, wherein each of the In oxide crystal grains has an In2O3 crystal single-phase structure that does not contain Fe substantially, and each of the ZnIn oxide crystal grains contains Fe.

Description

酸化物焼結体及びスパッタリングターゲットOxide sintered body and sputtering target
　本発明は、酸化物焼結体及びスパッタリングターゲットに関する。 The present invention relates to an oxide sintered body and a sputtering target.
　アモルファス酸化物半導体は、例えばアモルファスシリコン半導体に比べて薄膜トランジスタ（Ｔｈｉｎ　Ｆｉｌｍ　Ｔｒａｎｓｉｓｔｏｒ：ＴＦＴ）を形成した際のキャリア移動度が高い。また、アモルファス酸化物半導体は光学バンドギャップが大きく、可視光の透過性が高い。さらに、アモルファス酸化物半導体の薄膜は、アモルファスシリコン半導体よりも低温で成膜することができる。これらの特徴を活かして、アモルファス酸化物半導体の薄膜は、高解像度で高速駆動できる次世代の大型ディスプレイや、低温での成膜が要求される樹脂基板を用いた可撓性ディスプレイへの応用が期待されている。 Amorphous oxide semiconductors have higher carrier mobility when thin film transistors (TFTs) are formed than, for example, amorphous silicon semiconductors. In addition, amorphous oxide semiconductors have a large optical bandgap and high visible light transmission. Further, the thin film of the amorphous oxide semiconductor can be formed at a lower temperature than the amorphous silicon semiconductor. Taking advantage of these characteristics, the thin film of amorphous oxide semiconductor can be applied to next-generation large displays that can be driven at high speed with high resolution and flexible displays that use resin substrates that require film formation at low temperatures. It is expected.
　アモルファス酸化物半導体としては、インジウムを含む非晶質酸化物半導体が提案されており、インジウム、ガリウム、亜鉛及び酸素を含むＩｎ－Ｇａ－Ｚｎ－Ｏ（ＩＧＺＯ）アモルファス酸化物半導体や、インジウム、ガリウム、亜鉛、スズ及び酸素を含むＩｎ－Ｇａ－Ｚｎ－Ｓｎ－Ｏ（ＩＧＺＴＯ）アモルファス酸化物半導体が注目されている。 As the amorphous oxide semiconductor, an amorphous oxide semiconductor containing indium has been proposed, and an In-Ga-Zn-O (IGZO) amorphous oxide semiconductor containing indium, gallium, zinc and oxygen, indium and gallium. In-Ga-Zn-Sn-O (IGZTO) amorphous oxide semiconductors containing zinc, tin and oxygen are attracting attention.
　アモルファス酸化物半導体の薄膜は、このアモルファス酸化物半導体と同じ組成を有するスパッタリングターゲットを用いたスパッタリング法によって形成される。このスパッタリング法では、スパッタリング中に異常放電が生じると、スパッタリングターゲットが割れることがある。そのため、スパッタリングターゲットの割れを抑制するため、スパッタリングターゲット中の結晶相の含有量を調節することが検討されている（特開２０１４－５８４１５号公報参照）。 The thin film of the amorphous oxide semiconductor is formed by a sputtering method using a sputtering target having the same composition as this amorphous oxide semiconductor. In this sputtering method, if an abnormal discharge occurs during sputtering, the sputtering target may crack. Therefore, in order to suppress cracking of the sputtering target, it has been studied to adjust the content of the crystal phase in the sputtering target (see JP-A-2014-58415).
特開２０１４－５８４１５号公報Japanese Unexamined Patent Publication No. 2014-58415
　上記公報には、インジウム、ガリウム、亜鉛、スズ及び酸素を含むスパッタリングターゲットにおいて、スパッタリング中におけるスパッタリングターゲットの割れを抑制すべく、ＩｎＧａＺｎ２Ｏ５相の体積割合を３％以下に抑えることが記載されている。 The above publication describes that in a sputtering target containing indium, gallium, zinc, tin and oxygen, the volume ratio of InGaZn 2 O 5 phase is suppressed to 3% or less in order to suppress cracking of the sputtering target during sputtering. ing.
　しかしながら、本発明者等が鋭意検討したところ、ＩｎＧａＺｎ２Ｏ５等の結晶相の体積割合を制御するのみではスパッタリング中におけるスパッタリングターゲットの割れを十分に抑制することができない場合があることが分かった。 However, as a result of diligent studies by the present inventors, it has been found that cracking of the sputtering target during sputtering may not be sufficiently suppressed only by controlling the volume ratio of the crystal phase such as InGaZn 2 O 5 . ..
　本発明は、このような事情に基づいてなされたもので、割れの発生を抑制可能な酸化物焼結体及びスパッタリングターゲットを提供することを課題とする。 The present invention has been made based on such circumstances, and an object of the present invention is to provide an oxide sintered body and a sputtering target capable of suppressing the occurrence of cracks.
　上記課題を解決するためになされた本発明の一態様に係る酸化物焼結体は、Ｉｎ、Ｚｎ及びＦｅを含む酸化物焼結体であって、酸化亜鉛（ＺｎＯ）の結晶粒を実質的に有さず、Ｉｎ酸化物の結晶粒とＺｎＩｎ酸化物の結晶粒とを有し、上記Ｉｎ酸化物の結晶粒がＦｅを実質的に含まないＩｎ２Ｏ３結晶単相構造であり、上記ＺｎＩｎ酸化物の結晶粒がＦｅを含む。 The oxide sintered body according to one aspect of the present invention made to solve the above problems is an oxide sintered body containing In, Zn and Fe, and substantially contains crystal grains of zinc oxide (ZnO). In 2 O 3 crystal single-phase structure having In oxide crystal grains and ZnIn oxide crystal grains, and the In oxide crystal grains substantially containing no Fe, as described above. The grains of ZnIn oxide contain Fe.
　当該酸化物焼結体は、ＺｎＩｎ酸化物の結晶粒がＦｅを含むことで、酸化亜鉛の結晶粒を実質的に有さず、かつＺｎＩｎ酸化物の結晶粒を有する構成を得られる。当該酸化物焼結体は、酸化亜鉛の結晶粒を実質的に有さず、Ｉｎ酸化物の結晶粒とＺｎＩｎ酸化物の結晶粒とを有し、上記Ｉｎ酸化物の結晶粒がＦｅを実質的に含まないＩｎ２Ｏ３結晶単相構造であることで、割れの発生を抑制することができる。 Since the ZnIn oxide crystal grains contain Fe, the oxide sintered body can be obtained so as to have substantially no zinc oxide crystal grains and having ZnIn oxide crystal grains. The oxide sintered body has substantially no zinc oxide crystal grains, has In oxide crystal grains and ZnIn oxide crystal grains, and the In oxide crystal grains substantially contain Fe. The occurrence of cracks can be suppressed by having an In 2 O 3 crystal single-phase structure that does not contain the target.
　上記ＺｎＩｎ酸化物の結晶粒が、Ｚｎ２Ｉｎ２Ｏ５結晶単相構造ではないことが好ましい。このように、上記ＺｎＩｎ酸化物の結晶粒が、Ｚｎ２Ｉｎ２Ｏ５結晶単相構造ではないことで、強度を大きくしやすい。その結果、割れの発生をより確実に抑制することができる。 It is preferable that the crystal grains of the ZnIn oxide do not have a Zn 2 In 2 O 5 crystal single-phase structure. As described above, since the crystal grains of the ZnIn oxide do not have a Zn 2 In 2 O 5 crystal single-phase structure, the strength can be easily increased. As a result, the occurrence of cracks can be suppressed more reliably.
　上記ＺｎＩｎ酸化物の結晶粒が、Ｚｎ３Ｉｎ２Ｏ６、Ｚｎ４Ｉｎ２Ｏ７及びＺｎ５Ｉｎ２Ｏ８の結晶構造の少なくともいずれか１つを有するとよい。このように、上記ＺｎＩｎ酸化物の結晶粒が、Ｚｎ３Ｉｎ２Ｏ６、Ｚｎ４Ｉｎ２Ｏ７及びＺｎ５Ｉｎ２Ｏ８の結晶構造の少なくともいずれか１つを有することによって、バルク抵抗を抑えつつ、強度を大きくしやすい。 It is preferable that the crystal grains of the ZnIn oxide have at least one of the crystal structures of Zn 3 In 2 O 6 , Zn 4 In 2 O 7, and Zn 5 In 2 O 8 . As described above, the crystal grains of the ZnIn oxide have at least one of the crystal structures of Zn 3 In 2 O 6 , Zn 4 In 2 O 7, and Zn 5 In 2 O 8 to increase the bulk resistance. It is easy to increase the strength while suppressing it.
　当該酸化物焼結体は、ＺｎＩｎＦｅ酸化物の結晶粒を実質的に有しないことが好ましい。これにより、Ｆｅの含有割合を抑えつつ、酸化亜鉛の結晶粒を実質的に有さず、かつＺｎＩｎ酸化物の結晶粒を有する上述の構成を容易に得られる。 It is preferable that the oxide sintered body does not have substantially no crystal grains of ZnInFe oxide. As a result, it is possible to easily obtain the above-mentioned configuration having substantially no zinc oxide crystal grains and having ZnIn oxide crystal grains while suppressing the Fe content ratio.
　当該酸化物焼結体は、Ｉｎ、Ｚｎ及びＦｅの合計原子数に対し、Ｉｎの原子数が４５ａｔｍ％以上８０ａｔｍ％以下、Ｚｎの原子数が２０ａｔｍ％以上５５ａｔｍ％以下、Ｆｅの原子数が０．１ａｔｍ％以上１．５ａｔｍ％以下であるとよい。これにより、バルク抵抗を抑えつつ強度を大きくしやすい。その結果、割れの発生をより確実に抑制することができる。 The oxide sintered body has an In atom number of 45 atm% or more and 80 atm% or less, a Zn atom number of 20 atm% or more and 55 atm% or less, and an Fe atom number of 0 with respect to the total atomic number of In, Zn and Fe. It is preferable that it is 1 atm% or more and 1.5 atm% or less. As a result, it is easy to increase the strength while suppressing the bulk resistance. As a result, the occurrence of cracks can be suppressed more reliably.
　当該酸化物焼結体のバルク抵抗としては１×１０－２Ωｃｍ以下が好ましい。このように、バルク抵抗が上記上限以下であることによって、スパッタリング中における放電の不安定化を抑制することができ、異常放電に起因する当該酸化物焼結体の割れの発生を十分に抑制することができる。 The bulk resistance of the oxide sintered body is preferably 1 × 10 -2 Ωcm or less. As described above, when the bulk resistance is not more than the above upper limit, the destabilization of the discharge during sputtering can be suppressed, and the occurrence of cracks in the oxide sintered body due to the abnormal discharge is sufficiently suppressed. be able to.
　当該酸化物焼結体の相対密度としては９６％以上が好ましい。このように、相対密度が上記下限以上であることによって、強度を大きくすることで割れの発生を十分に抑制することができる。 The relative density of the oxide sintered body is preferably 96% or more. As described above, when the relative density is at least the above lower limit, the occurrence of cracks can be sufficiently suppressed by increasing the strength.
　上記課題を解決するためになされた本発明の他の一態様に係るスパッタリングターゲットは、Ｉｎ、Ｚｎ及びＦｅを含むスパッタリングターゲットであって、酸化亜鉛（ＺｎＯ）の結晶粒を実質的に有さず、Ｉｎ酸化物の結晶粒とＺｎＩｎ酸化物の結晶粒とを有し、上記Ｉｎ酸化物の結晶粒がＦｅを実質的に含まないＩｎ２Ｏ３結晶単相構造であり、上記ＺｎＩｎ酸化物の結晶粒がＦｅを含む。 The sputtering target according to another aspect of the present invention made to solve the above problems is a sputtering target containing In, Zn and Fe, and has substantially no crystal grains of zinc oxide (ZnO). , and a grain of the crystal grains and ZnIn oxides of in oxide, the crystal grains of the in oxide is in 2 O 3 crystal single phase structure is substantially free of Fe, the ZnIn oxide The crystal grains contain Fe.
　当該スパッタリングターゲットは割れの発生を抑制することができる。 The sputtering target can suppress the occurrence of cracks.
　なお、本発明において、「結晶粒」とは、走査型電子顕微鏡（ＳＥＭ）によって１０００倍で観察した反射電子像における粒界相に囲まれた領域をいう。また、「結晶粒がＦｅを含む」とは、エネルギー分散型Ｘ線分光（ＥＤＸ）によって結晶粒の元素分析を行った場合にＦｅがその結晶粒中に０．１ａｔｍ％以上検出されることをいい、「結晶粒がＦｅを実質的に含まない」とは、Ｆｅがその結晶粒中に０．１ａｔｍ％以上検出されないことをいう。「結晶粒を実質的に有しない」とは、走査型電子顕微鏡（ＳＥＭ）によって１０００倍で観察した反射電子像において粒界相に囲まれる領域が視認されないことをいう。「バルク抵抗」とは、４探針法で測定される体積抵抗をいう。「相対密度」とは、（実測密度／真密度）×１００［％］で算出される値をいう。また、「実測密度」とは、アルキメデス法によって求められる値をいう。 In the present invention, the "crystal grain" refers to a region surrounded by grain boundary phases in a reflected electron image observed at a magnification of 1000 by a scanning electron microscope (SEM). Further, "crystal grains contain Fe" means that Fe is detected in the crystal grains at 0.1 atm% or more when elemental analysis of the crystal grains is performed by energy dispersive X-ray spectroscopy (EDX). That is, "the crystal grains do not substantially contain Fe" means that Fe is not detected in the crystal grains in an amount of 0.1 atm% or more. "Substantially free of crystal grains" means that the region surrounded by the grain boundary phase is not visible in the reflected electron image observed at 1000 times by a scanning electron microscope (SEM). "Bulk resistance" refers to the volumetric resistance measured by the 4-probe method. The "relative density" means a value calculated by (measured density / true density) x 100 [%]. The "measured density" means a value obtained by the Archimedes method.
　以上説明したように、本発明に係る酸化物焼結体及びスパッタリングターゲットは、割れの発生を抑制することができる。 As described above, the oxide sintered body and the sputtering target according to the present invention can suppress the occurrence of cracks.
図１は、本発明の一実施形態に係る酸化物焼結体を示す模式的断面図である。FIG. 1 is a schematic cross-sectional view showing an oxide sintered body according to an embodiment of the present invention. 図２は、Ｎｏ．３の酸化物焼結体の反射電子像である。FIG. 2 shows No. It is a reflected electron image of the oxide sintered body of 3. 図３は、Ｎｏ．４の酸化物焼結体の反射電子像である。FIG. 3 shows No. It is a reflected electron image of the oxide sintered body of 4. 図４は、Ｎｏ．５の酸化物焼結体の反射電子像である。FIG. 4 shows No. It is a reflected electron image of the oxide sintered body of 5. 図５は、Ｎｏ．６の酸化物焼結体の反射電子像である。FIG. 5 shows No. It is a reflected electron image of the oxide sintered body of 6. 図６は、Ｎｏ．７の酸化物焼結体の反射電子像である。FIG. 6 shows No. It is a reflected electron image of the oxide sintered body of 7. 図７は、Ｎｏ．１の酸化物焼結体の反射電子像である。FIG. 7 shows No. It is a reflected electron image of the oxide sintered body of 1. 図８は、Ｎｏ．９の酸化物焼結体の反射電子像である。FIG. 8 shows No. 9 is a backscattered electron image of the oxide sintered body of 9. 図９は、Ｎｏ．１０の酸化物焼結体の反射電子像である。FIG. 9 shows No. It is a reflected electron image of 10 oxide sintered body. 図１０は、Ｎｏ．１２の酸化物焼結体の反射電子像である。FIG. 10 shows No. It is a reflected electron image of 12 oxide sintered bodies. 図１１は、Ｎｏ．９の酸化物焼結体のＸ線回折スペクトルの解析結果である。FIG. 11 shows No. It is an analysis result of the X-ray diffraction spectrum of the oxide sintered body of 9. 図１２は、Ｎｏ．１０の酸化物焼結体のＸ線回折スペクトルの解析結果である。FIG. 12 shows No. It is an analysis result of the X-ray diffraction spectrum of 10 oxide sintered bodies. 図１３は、Ｎｏ．１３の酸化物焼結体のＸ線回折スペクトルの解析結果である。FIG. 13 shows No. It is the analysis result of the X-ray diffraction spectrum of the oxide sintered body of 13. 図１４は、Ｎｏ．１４の酸化物焼結体のＸ線回折スペクトルの解析結果である。FIG. 14 shows No. It is the analysis result of the X-ray diffraction spectrum of 14 oxide sintered bodies.
　以下、図面を参照しつつ、本発明の実施の形態を詳説する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
［酸化物焼結体］
　図１の酸化物焼結体１は、Ｉｎ（インジウム）、Ｚｎ（亜鉛）及びＦｅ（鉄）を含む。当該酸化物焼結体１は、Ｉｎ酸化物の結晶粒と、ＺｎＩｎ酸化物の結晶粒とを有する。当該酸化物焼結体１は、酸化亜鉛の結晶粒を実質的に有しない（すなわち、Ｚｎ以外の金属元素を実質的に含まない酸化物の結晶粒を実質的に有しない）。上記ＺｎＩｎ酸化物の結晶粒はＦｅを含む。上記Ｉｎ酸化物の結晶粒は、Ｆｅを実質的に含まないＩｎ２Ｏ３結晶単相構造である。なお、Ｉｎ酸化物の結晶粒の結晶構造及びＺｎＩｎ酸化物の結晶粒の結晶構造は、各結晶粒のＸ線回折スペクトルを解析して求めることができる。 [Oxide sintered body]
The oxide sintered body 1 of FIG. 1 contains In (indium), Zn (zinc) and Fe (iron). The oxide sintered body 1 has In oxide crystal grains and ZnIn oxide crystal grains. The oxide sintered body 1 has substantially no zinc oxide crystal grains (that is, has substantially no oxide crystal grains that do not substantially contain metal elements other than Zn). The crystal grains of the ZnIn oxide contain Fe. The crystal grains of the In oxide have an In 2 O 3 crystal single-phase structure that does not substantially contain Fe. The crystal structure of the In oxide crystal grains and the crystal structure of the ZnIn oxide crystal grains can be obtained by analyzing the X-ray diffraction spectrum of each crystal grain.
　当該酸化物焼結体１は、金属元素として、Ｉｎ、Ｚｎ及びＦｅと不可避的不純物とを含んでいてもよい。換言すると、当該酸化物焼結体１は、Ｉｎ、Ｚｎ及びＦｅ以外の金属元素を実質的に含まないことが好ましい。 The oxide sintered body 1 may contain In, Zn and Fe and unavoidable impurities as metal elements. In other words, it is preferable that the oxide sintered body 1 does not substantially contain metal elements other than In, Zn and Fe.
　当該酸化物焼結体１は、例えばアモルファス酸化物半導体の薄膜を形成可能なスパッタリングターゲットに用いられる。Ｉｎは、上記薄膜のキャリア移動度の向上に寄与する。また、Ｚｎは、上記薄膜のアモルファス構造の安定化に寄与する。 The oxide sintered body 1 is used, for example, as a sputtering target capable of forming a thin film of an amorphous oxide semiconductor. In contributes to the improvement of carrier mobility of the thin film. Further, Zn contributes to the stabilization of the amorphous structure of the thin film.
　上述のように、Ｆｅは、上記ＺｎＩｎ酸化物の結晶粒に含まれる。詳しくは、当該酸化物焼結体１は、Ｚｎ及びＩｎ以外の金属元素を実質的に含まないＺｎＩｎ酸化物の結晶粒を有しており、このＺｎＩｎ酸化物の結晶粒の結晶構造中にＦｅが固溶している。当該酸化物焼結体１は、ＦｅをＺｎＩｎ酸化物の結晶粒の結晶構造中に固溶させることで、Ｆｅの微量の添加によって、酸化亜鉛とＩｎ酸化物との化合物（具体的には、Ｉｎ２Ｏ３とＺｎＯとの化合物）である上記ＺｎＩｎ酸化物の成長を大幅に促すことができる。すなわち、当該酸化物焼結体１は、Ｆｅの微量の添加によって、酸化亜鉛の結晶粒をなくすと共に、上記ＺｎＩｎ酸化物の体積率を大幅に高めることができる。これにより、当該酸化物焼結体１は、Ｚｎの均一分散性を高めやすいと考えられる。 As described above, Fe is contained in the crystal grains of the ZnIn oxide. Specifically, the oxide sintered body 1 has ZnIn oxide crystal grains that substantially do not contain metal elements other than Zn and In, and Fe is contained in the crystal structure of the ZnIn oxide crystal grains. Is solidly dissolved. In the oxide sintered body 1, Fe is dissolved in the crystal structure of the crystal grains of ZnIn oxide, and by adding a small amount of Fe, a compound of zinc oxide and In oxide (specifically, The growth of the ZnIn oxide, which is a compound of In 2 O 3 and Zn O), can be significantly promoted. That is, the oxide sintered body 1 can eliminate the crystal grains of zinc oxide and significantly increase the volume fraction of the ZnIn oxide by adding a small amount of Fe. As a result, it is considered that the oxide sintered body 1 can easily improve the uniform dispersibility of Zn.
　上記ＺｎＩｎ酸化物の結晶粒は、Ｚｎ２Ｉｎ２Ｏ５結晶単相構造ではないことが好ましい。当該酸化物焼結体１は、Ｆｅの添加量が増加すると、上記ＺｎＩｎ酸化物の結晶粒としてＺｎ２Ｉｎ２Ｏ５の割合が大きくなる。また、例えばＦｅの添加量が大きくなり過ぎると、上記ＺｎＩｎ酸化物の結晶粒がＺｎ２Ｉｎ２Ｏ５結晶単相構造となり、結晶内の空孔面積が大きくなるとともに微小なクラックが形成されやすくなる。そのため、当該酸化物焼結体１は、上記ＺｎＩｎ酸化物の結晶粒が、Ｚｎ２Ｉｎ２Ｏ５結晶単相構造ではないことで、強度を大きくし、割れの発生をより確実に抑制することができる。また、当該酸化物焼結体１は、上記ＺｎＩｎ酸化物の結晶粒が、Ｚｎ２Ｉｎ２Ｏ５結晶単相構造ではないことで、Ｆｅの添加量を抑え、バルク抵抗を小さく制御しやすい。 It is preferable that the crystal grains of the ZnIn oxide do not have a Zn 2 In 2 O 5 crystal single-phase structure. In the oxide sintered body 1, as the amount of Fe added increases, the proportion of Zn 2 In 2 O 5 as the crystal grains of the Zn In oxide increases. Further, for example, when the amount of Fe added becomes too large, the crystal grains of the ZnIn oxide have a Zn 2 In 2 O 5 crystal single-phase structure, the pore area in the crystal becomes large, and minute cracks are likely to be formed. Become. Therefore, in the oxide sintered body 1, the crystal grains of the ZnIn oxide do not have a Zn 2 In 2 O 5 crystal single-phase structure, so that the strength is increased and the occurrence of cracks is more reliably suppressed. Can be done. Further, in the oxide sintered body 1, since the crystal grains of the ZnIn oxide do not have a Zn 2 In 2 O 5 crystal single-phase structure, the amount of Fe added can be suppressed and the bulk resistance can be easily controlled to be small.
　上記ＺｎＩｎ酸化物の結晶粒が、Ｚｎ３Ｉｎ２Ｏ６、Ｚｎ４Ｉｎ２Ｏ７及びＺｎ５Ｉｎ２Ｏ８の結晶構造の少なくともいずれか１つを有することが好ましい。これにより、当該酸化物焼結体１は、バルク抵抗を抑えると共に強度を大きくしやすい。この場合、上記ＺｎＩｎ酸化物の結晶粒は、Ｚｎ２Ｉｎ２Ｏ５の結晶構造を有しないことが好ましい。 It is preferable that the crystal grains of the ZnIn oxide have at least one of the crystal structures of Zn 3 In 2 O 6 , Zn 4 In 2 O 7, and Zn 5 In 2 O 8 . As a result, the oxide sintered body 1 tends to suppress bulk resistance and increase its strength. In this case, it is preferable that the crystal grains of the ZnIn oxide do not have the crystal structure of Zn 2 In 2 O 5 .
　当該酸化物焼結体１は、ＺｎＩｎＦｅ酸化物の結晶粒を実質的に有しないことが好ましい。これにより、当該酸化物焼結体１は、Ｆｅの含有割合を抑えつつ、酸化亜鉛の結晶粒を実質的に有さず、かつＺｎＩｎ酸化物の結晶粒を有する上述の構成を容易に得られる。つまり、当該酸化物焼結体１は、上述のように、ＦｅをＺｎＩｎ酸化物の結晶粒の結晶構造中に選択的に固溶させることで、Ｆｅの含有割合を抑えつつ、酸化亜鉛の結晶粒をなくすと共に、ＺｎＩｎ酸化物の結晶粒を効率的に成長させることができる。 It is preferable that the oxide sintered body 1 does not substantially have crystal grains of ZnInFe oxide. As a result, the above-mentioned configuration can be easily obtained in the oxide sintered body 1 having substantially no zinc oxide crystal grains and having ZnIn oxide crystal grains while suppressing the Fe content ratio. .. That is, as described above, the oxide sintered body 1 selectively dissolves Fe in the crystal structure of the crystal grains of ZnIn oxide, thereby suppressing the content ratio of Fe and the zinc oxide crystal. It is possible to eliminate grains and efficiently grow ZnIn oxide crystal grains.
　Ｉｎ、Ｚｎ及びＦｅの合計原子数に対するＩｎの原子数の下限としては、４５ａｔｍ％が好ましく、５０ａｔｍ％がより好ましい。一方、上記原子数の上限としては、８０ａｔｍ％が好ましく、７５ａｔｍ％がより好ましく、７０ａｔｍ％がさらに好ましい。上記原子数が上記下限に満たないと、当該酸化物焼結体１を用いて形成されるアモルファス酸化物半導体の薄膜のキャリア移動度が不十分になるおそれがある。逆に、上記原子数が上記上限を超えると、上記薄膜のリーク電流が増大したり、閾値電圧が負側にシフトしたりするため、上記薄膜が導体化するおそれがある。 As the lower limit of the number of atoms of In with respect to the total number of atoms of In, Zn and Fe, 45 atm% is preferable, and 50 atm% is more preferable. On the other hand, the upper limit of the number of atoms is preferably 80 atm%, more preferably 75 atm%, and even more preferably 70 atm%. If the number of atoms is less than the above lower limit, the carrier mobility of the thin film of the amorphous oxide semiconductor formed by using the oxide sintered body 1 may be insufficient. On the contrary, when the number of atoms exceeds the upper limit, the leak current of the thin film increases or the threshold voltage shifts to the negative side, so that the thin film may become a conductor.
　Ｉｎ、Ｚｎ及びＦｅの合計原子数に対するＺｎの原子数の下限としては、２０ａｔｍ％が好ましく、２５ａｔｍ％がより好ましく、３０ａｔｍ％がさらに好ましい。一方、上記原子数の上限としては、５５ａｔｍ％が好ましく、５０ａｔｍ％がより好ましい。上記原子数が上記下限に満たないと、他の金属原子数が相対的に大きくなることで、上記薄膜が導体化するおそれがある。逆に、上記原子数が上記上限を超えると、キャリア濃度が抑制され、上記薄膜のキャリア移動度が不十分となるおそれがある。 As the lower limit of the number of atoms of Zn with respect to the total number of atoms of In, Zn and Fe, 20 atm% is preferable, 25 atm% is more preferable, and 30 atm% is further preferable. On the other hand, as the upper limit of the number of atoms, 55 atm% is preferable, and 50 atm% is more preferable. If the number of atoms is less than the above lower limit, the number of other metal atoms becomes relatively large, which may cause the thin film to become a conductor. On the contrary, when the number of atoms exceeds the above upper limit, the carrier concentration may be suppressed and the carrier mobility of the thin film may be insufficient.
　Ｉｎ、Ｚｎ及びＦｅの合計原子数に対するＦｅの原子数の下限としては、０．１ａｔｍ％が好ましく、０．３ａｔｍ％がより好ましい。一方、上記原子数の上限としては、１．５ａｔｍ％が好ましく、１．０ａｔｍ％がより好ましい。上記原子数が上記下限に満たないと、ＺｎＩｎ酸化物の結晶粒の成長を十分に促進することができないおそれがある。一方、上記原子数が上記上限を超えると、当該酸化物焼結体１のバルク抵抗が大きくなるおそれや、当該酸化物焼結体１の相対密度が不十分となるおそれがある。 As the lower limit of the number of atoms of Fe with respect to the total number of atoms of In, Zn and Fe, 0.1 atm% is preferable, and 0.3 atm% is more preferable. On the other hand, the upper limit of the number of atoms is preferably 1.5 atm%, more preferably 1.0 atm%. If the number of atoms is less than the above lower limit, the growth of ZnIn oxide crystal grains may not be sufficiently promoted. On the other hand, if the number of atoms exceeds the above upper limit, the bulk resistance of the oxide sintered body 1 may increase, or the relative density of the oxide sintered body 1 may become insufficient.
　当該酸化物焼結体１は、Ｉｎ、Ｚｎ及びＦｅの合計原子数に対し、Ｉｎの原子数が４５ａｔｍ％以上８０ａｔｍ％以下、Ｚｎの原子数が２０ａｔｍ％以上５５ａｔｍ％以下、Ｆｅの原子数が０．１ａｔｍ％以上１．５ａｔｍ％以下であることが好ましく、Ｉｎの原子数が５０ａｔｍ％以上７０ａｔｍ％以下、Ｚｎの原子数が３０ａｔｍ％以上５０ａｔｍ％以下、Ｆｅの原子数が０．１ａｔｍ％以上１．０ａｔｍ％以下であることがより好ましい。当該酸化物焼結体１は、Ｉｎ、Ｚｎ及びＦｅの原子数を上記範囲内に調節することで、バルク抵抗を抑えつつ強度を大きくしやすい。その結果、割れの発生をより確実に抑制することができる。 The oxide sintered body 1 has an In atom number of 45 atm% or more and 80 atm% or less, a Zn atom number of 20 atm% or more and 55 atm% or less, and a Fe atom number with respect to the total atomic number of In, Zn and Fe. It is preferably 0.1 atm% or more and 1.5 atm% or less, the number of In atoms is 50 atm% or more and 70 atm% or less, the number of Zn atoms is 30 atm% or more and 50 atm% or less, and the number of Fe atoms is 0.1 atm% or more. It is more preferably 1.0 atom% or less. By adjusting the number of atoms of In, Zn and Fe within the above range, the oxide sintered body 1 can easily increase its strength while suppressing the bulk resistance. As a result, the occurrence of cracks can be suppressed more reliably.
　当該酸化物焼結体１のバルク抵抗の上限としては、１×１０－２Ωｃｍが好ましく、５×１０－３Ωｃｍがより好ましく、４×１０－３Ωｃｍがさらに好ましい。上記バルク抵抗が上記上限を超えると、スパッタリング中に放電の不安定化を招来するおそれがあり、異常放電に起因して当該酸化物焼結体１に割れが生じるおそれがある。なお、上記バルク抵抗の下限としては、特に限定されるものではないが、例えば１×１０－４Ωｃｍとすることができる。 As the upper limit of the bulk resistance of the oxide sintered body 1, 1 × 10 −2 Ωcm is preferable, 5 × 10 -3 Ωcm is more preferable, and 4 × 10 -3 Ωcm is further preferable. If the bulk resistance exceeds the upper limit, the discharge may become unstable during sputtering, and the oxide sintered body 1 may be cracked due to the abnormal discharge. The lower limit of the bulk resistance is not particularly limited, but may be, for example, 1 × 10 -4 Ωcm.
　当該酸化物焼結体１の相対密度の下限としては、９６％が好ましく、９７％がより好ましい。上記相対密度が上記下限に満たないと、強度が不十分となり割れを生じるおそれがある。なお、上記相対密度は大きい方が好ましく、その上限としては、例えば１００％とすることができる。 The lower limit of the relative density of the oxide sintered body 1 is preferably 96%, more preferably 97%. If the relative density does not reach the lower limit, the strength becomes insufficient and cracks may occur. The relative density is preferably large, and the upper limit thereof can be, for example, 100%.
＜利点＞
　当該酸化物焼結体１は、ＺｎＩｎ酸化物の結晶粒がＦｅを含むことで、酸化亜鉛の結晶粒を実質的に有さず、かつＺｎＩｎ酸化物の結晶粒を有する構成を容易に得られる。当該酸化物焼結体１は、酸化亜鉛の結晶粒を実質的に有さず、Ｉｎ酸化物の結晶粒とＺｎＩｎ酸化物の結晶粒とを有し、上記Ｉｎ酸化物の結晶粒がＦｅを実質的に含まないＩｎ２Ｏ３結晶単相構造であることで、割れの発生を抑制することができる。 <Advantage>
Since the ZnIn oxide crystal grains contain Fe, the oxide sintered body 1 can be easily obtained to have a structure in which it has substantially no zinc oxide crystal grains and has ZnIn oxide crystal grains. .. The oxide sintered body 1 has substantially no zinc oxide crystal grains, has In oxide crystal grains and ZnIn oxide crystal grains, and the In oxide crystal grains contain Fe. The occurrence of cracks can be suppressed by having an In 2 O 3 crystal single-phase structure that is substantially free of.
［スパッタリングターゲット］
　次に、本発明の他の一態様であるスパッタリングターゲットについて説明する。当該スパッタリングターゲットは、Ｉｎ、Ｚｎ及びＦｅを含むスパッタリングターゲットであって、酸化亜鉛の結晶粒を実質的に有さず、Ｉｎ酸化物の結晶粒とＺｎＩｎ酸化物の結晶粒とを有し、上記Ｉｎ酸化物の結晶粒がＦｅを実質的に含まないＩｎ２Ｏ３結晶単相構造であり、上記ＺｎＩｎ酸化物の結晶粒がＦｅを含む。当該スパッタリングターゲットは、図１の酸化物焼結体１を有する。当該スパッタリングターゲットの具体的構成は、当該酸化物焼結体１と同じである。 [Sputtering target]
Next, a sputtering target, which is another aspect of the present invention, will be described. The sputtering target is a sputtering target containing In, Zn, and Fe, which has substantially no zinc oxide crystal grains and has In oxide crystal grains and ZnIn oxide crystal grains. The crystal grains of the In oxide have an In 2 O 3 crystal single-phase structure that does not substantially contain Fe, and the crystal grains of the ZnIn oxide contain Fe. The sputtering target has the oxide sintered body 1 of FIG. The specific configuration of the sputtering target is the same as that of the oxide sintered body 1.
＜利点＞
　当該スパッタリングターゲットは、当該酸化物焼結体１と同様に割れの発生を抑制することができる。 <Advantage>
The sputtering target can suppress the occurrence of cracks in the same manner as the oxide sintered body 1.
［その他の実施形態］
　上記実施形態は、本発明の構成を限定するものではない。従って、上記実施形態は、本明細書の記載及び技術常識に基づいて上記実施形態各部の構成要素の省略、置換又は追加が可能であり、それらは全て本発明の範囲に属するものと解釈されるべきである。 [Other Embodiments]
The above embodiment does not limit the configuration of the present invention. Therefore, in the above-described embodiment, the components of each part of the above-described embodiment can be omitted, replaced or added based on the description of the present specification and common general technical knowledge, and all of them are construed as belonging to the scope of the present invention. Should be.
　例えば、当該酸化物焼結体及びスパッタリングターゲットは、他の金属元素として、例えばＳｎ（錫）を含んでいてもよい。 For example, the oxide sintered body and the sputtering target may contain, for example, Sn (tin) as another metal element.
　以下、実施例に基づき本発明を詳述するが、この実施例の記載に基づいて本発明が限定的に解釈されるものではない。 Hereinafter, the present invention will be described in detail based on Examples, but the present invention is not limitedly interpreted based on the description of this Example.
（ホットプレスによる酸化物焼結体の作製）
〔Ｎｏ．１、Ｎｏ．２〕
　純度９９．９９％の酸化亜鉛粉末（ＺｎＯ）、純度９９．９９％の酸化インジウム粉末（Ｉｎ２Ｏ３）、純度９９．４％の酸化鉄粉末（Ｆｅ２Ｏ３）を表１に示す原子数比率で配合して原料粉末を得た。この原料粉末に水を加えて、ナイロンポッド及びメディアとしてジルコニアボールを使用したボールミルで１８時間混合及び粉砕した。次に、得られた混合粉末を乾燥して造粒を行った。造粒後の混合粉末を黒鉛型にセットし、表１の条件でホットプレスを行った。このホットプレスでは、炉内にはＮ２ガスを導入し、Ｎ２雰囲気下で焼結した。 (Preparation of oxide sintered body by hot pressing)
[No. 1, No. 2]
Zinc oxide powder with a purity of 99.99% (ZnO), indium oxide powder with a purity of 99.99% (In 2 O 3 ), and iron oxide powder with a purity of 99.4% (Fe 2 O 3 ) are shown in Table 1. Raw material powder was obtained by blending in several ratios. Water was added to this raw material powder, and the mixture was mixed and pulverized for 18 hours in a ball mill using a nylon pod and zirconia balls as a medium. Next, the obtained mixed powder was dried and granulated. The mixed powder after granulation was set in a graphite mold and hot-pressed under the conditions shown in Table 1. In this hot press, N 2 gas was introduced into the furnace and sintered in an N 2 atmosphere.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　得られた酸化物焼結体のＸ線回折スペクトルを解析し、Ｉｎ酸化物、酸化亜鉛及びＺｎＩｎ酸化物の結晶粒の結晶構造及び含有割合を求めた。その結果を表２に示す。 The X-ray diffraction spectrum of the obtained oxide sintered body was analyzed, and the crystal structure and content ratio of the crystal grains of In oxide, zinc oxide and ZnIn oxide were determined. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１及び表２に示すように、Ｆｅの微量の添加によって、Ｉｎ２Ｏ３とＺｎＯとの化合物であるＺｎＩｎ酸化物（Ｚｎ５Ｉｎ２Ｏ８）の成長が大幅に促進されていることが分かる。 As shown in Tables 1 and 2, the growth of ZnIn oxide (Zn 5 In 2 O 8 ), which is a compound of In 2 O 3 and Zn O, is significantly promoted by the addition of a small amount of Fe. I understand.
（常圧焼結による酸化物焼結体の作製）
〔Ｎｏ．３～Ｎｏ．８〕
　純度９９．９９％の酸化亜鉛粉末（ＺｎＯ）、純度９９．９９％の酸化インジウム粉末（Ｉｎ２Ｏ３）、純度９９．４％の酸化鉄粉末（Ｆｅ２Ｏ３）を表３に示す原子数比率で配合して原料粉末を得た。水と、ポリビニルアルコールを主成分とするバインダーと、アクリル系重合体を主成分とする分散剤とを加えて、ナイロンポッド及びメディアとしてジルコニアボールを使用したボールミルで３時間混合及び粉砕した。次に、得られた混合粉末を乾燥して造粒を行った。造粒後の混合粉末を成形型に入れ、冷間静水圧プレスで３ｔｏｎ／ｃｍ２で加圧して成形体を得た。この成形体を、常圧、大気雰囲気下で１５５０℃まで昇温し、２時間保持後、自然降温して焼結し、Ｎｏ．３～Ｎｏ．８の酸化物焼結体を得た。Ｎｏ．３～Ｎｏ．７について、走査型電子顕微鏡（ＳＥＭ）によって１０００倍で観察した反射電子像を図２～図６に示す。 (Preparation of oxide sintered body by atmospheric pressure sintering)
[No. 3 to No. 8]
The atoms shown in Table 3 are zinc oxide powder (ZnO) with a purity of 99.99%, indium oxide powder with a purity of 99.99% (In 2 O 3 ), and iron oxide powder with a purity of 99.4% (Fe 2 O 3 ). Raw material powder was obtained by blending in several ratios. Water, a binder containing polyvinyl alcohol as a main component, and a dispersant containing an acrylic polymer as a main component were added, and the mixture was mixed and pulverized in a ball mill using a nylon pod and zirconia balls as a medium for 3 hours. Next, the obtained mixed powder was dried and granulated. The mixed powder after granulation was placed in a molding die and pressed at 3 ton / cm 2 with a cold hydrostatic press to obtain a molded product. This molded product was heated to 1550 ° C. under normal pressure and atmospheric atmosphere, held for 2 hours, naturally lowered to a temperature, and sintered. 3 to No. An oxide sintered body of 8 was obtained. No. 3 to No. The reflected electron images of No. 7 observed at 1000 times by a scanning electron microscope (SEM) are shown in FIGS. 2 to 6.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
〔結晶構造〕
　Ｎｏ．３～Ｎｏ．８について、Ｘ線回折スペクトルを解析し、Ｉｎ酸化物、酸化亜鉛及びＺｎＩｎ酸化物の結晶粒の結晶構造を求めた。図２～図６に示すように、Ｎｏ．３～Ｎｏ．７は、Ｉｎ酸化物の結晶粒（Ｉｎ２Ｏ３結晶単相構造）Ｘ及びＺｎＩｎ酸化物の結晶粒Ｙを有する一方、酸化亜鉛の結晶粒を実質的に有していない。また、Ｘ線回折スペクトルの解析の結果、Ｆｅの添加量が０．９ａｔｍ％以下であるＮｏ．３、Ｎｏ．４及びＮｏ．７では、ＺｎＩｎ酸化物の結晶粒がＺｎ３Ｉｎ２Ｏ６の結晶単相構造であるのに対し、Ｆｅの添加量を１．５ａｔｍ％に増やしたＮｏ．５では、ＺｎＩｎ酸化物の結晶粒がＺｎ３Ｉｎ２Ｏ６とＺｎ２Ｉｎ２Ｏ５とを有しており、Ｚｎ３Ｉｎ２Ｏ６内に縞状組織が現れている。また、Ｆｅの添加量を５．０ａｔｍ％まで増加させたＮｏ．６では、上記縞状組織はなくなっており、ＺｎＩｎ酸化物の結晶粒は、Ｚｎ２Ｉｎ２Ｏ５の結晶単相構造となっている。 〔Crystal structure〕
No. 3 to No. The X-ray diffraction spectrum of No. 8 was analyzed to determine the crystal structure of the crystal grains of In oxide, zinc oxide and ZnIn oxide. As shown in FIGS. 2 to 6, No. 3 to No. 7 has In oxide crystal grains (In 2 O 3 crystal single-phase structure) X and Zn In oxide crystal grains Y, but does not substantially have zinc oxide crystal grains. Further, as a result of the analysis of the X-ray diffraction spectrum, the amount of Fe added was 0.9 atm% or less. 3, No. 4 and No. In No. 7, the crystal grains of ZnIn oxide had a crystal single-phase structure of Zn 3 In 2 O 6 , whereas the amount of Fe added was increased to 1.5 atm%. In No. 5, the crystal grains of the ZnIn oxide have Zn 3 In 2 O 6 and Zn 2 In 2 O 5, and a striped structure appears in Zn 3 In 2 O 6 . In addition, No. 1 in which the amount of Fe added was increased to 5.0 atm%. In No. 6, the striped structure has disappeared, and the crystal grains of the ZnIn oxide have a crystal single-phase structure of Zn 2 In 2 O 5 .
　図２、図３及び図６から分かるように、Ｆｅの添加量を０．９ａｔｍ％まで増加させていくことで、Ｉｎ酸化物の結晶粒（Ｉｎ２Ｏ３）の面積が低下すると共に、ＺｎＩｎ酸化物の結晶粒（Ｚｎ３Ｉｎ２Ｏ６）の面積が増大している。また、図２～図６から分かるように、Ｆｅの添加量が多くなるに伴って、結晶粒内の空孔Ｚの面積が大きくなっている。加えて、図５から分かるように、Ｆｅの添加量を５．０ａｔｍ％まで増加させたＮｏ．６では、微小なクラックが形成されている。 As can be seen from FIGS. 2, 3 and 6, by increasing the amount of Fe added to 0.9 atm%, the area of In oxide crystal grains (In 2 O 3 ) is reduced and ZnIn is increased. The area of oxide crystal grains (Zn 3 In 2 O 6 ) is increasing. Further, as can be seen from FIGS. 2 to 6, the area of the pores Z in the crystal grains increases as the amount of Fe added increases. In addition, as can be seen from FIG. 5, the amount of Fe added was increased to 5.0 atm%. In No. 6, minute cracks are formed.
〔相対密度〕
　Ｎｏ．３～Ｎｏ．８について、アルキメデス法で計測した相対密度を表４に示す。 [Relative density]
No. 3 to No. Table 4 shows the relative densities measured by the Archimedes method for item 8.
〔バルク抵抗〕
　Ｎｏ．３～Ｎｏ．８について、４探針法で測定したバルク密度を表４に示す。 [Bulk resistance]
No. 3 to No. Table 4 shows the bulk densities measured by the 4-probe method for No. 8.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表４から分かるように、Ｆｅの添加量が多くなるにつれて酸化物焼結体の相対密度が小さくなっており、Ｆｅの添加量が５．０ａｔｍ％になると相対密度は８７％程度まで小さくなっている。 As can be seen from Table 4, the relative density of the oxide sintered body decreases as the amount of Fe added increases, and when the amount of Fe added reaches 5.0 atm%, the relative density decreases to about 87%. There is.
　また、表４から分かるように、Ｆｅの添加量が１．５ａｔｍ％以下の場合にはバルク抵抗は３．７×１０－３Ωｃｍ以下に制御できているが、Ｆｅの添加量が５．０ａｔｍ％まで増加するとバルク抵抗は８×１０－３以上に増加すると共に不安定化している。 Further, as can be seen from Table 4, when the amount of Fe added is 1.5 atm% or less, the bulk resistance can be controlled to 3.7 × 10 -3 Ωcm or less, but the amount of Fe added is 5.0 atm. When it increases to%, the bulk resistance increases to 8 × 10 -3 or more and becomes unstable.
〔Ｆｅの存在場所〕
　ホットプレス法で作製したＮｏ．１の酸化物焼結体の反射電子像を図７に示す。表２にも示すように、この酸化物焼結体のＸ線回折スペクトルを解析したところ、Ｉｎ２Ｏ３、ＺｎＯ及びＺｎ５Ｉｎ２Ｏ８以外の結晶粒は観察されなかった。この酸化物焼結体におけるＩｎ酸化物の結晶粒（Ｉｎ２Ｏ３結晶単相構造）Ｘ、ＺｎＩｎ酸化物の結晶粒（Ｚｎ５Ｉｎ２Ｏ８結晶単相構造）Ｙ、及び酸化亜鉛の結晶粒（ＺｎＯ結晶単相構造）Ｐに対し、エネルギー分散型Ｘ線分光（ＥＤＸ）によって元素分析を行った結果を表５に示す。 [Location of Fe]
No. produced by the hot press method. The reflected electron image of the oxide sintered body of No. 1 is shown in FIG. As shown in Table 2, when the X-ray diffraction spectrum of this oxide sintered body was analyzed, no crystal grains other than In 2 O 3 , Zn O and Zn 5 In 2 O 8 were observed. In oxide crystal grains (In 2 O 3 crystal single-phase structure) X, Zn In oxide crystal grains (Zn 5 In 2 O 8 crystal single-phase structure) Y, and zinc oxide crystals in this oxide sintered body. Table 5 shows the results of elemental analysis of grains (ZnO crystal single-phase structure) P by energy dispersion type X-ray spectroscopy (EDX).
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　上述のように、Ｘ線回折スペクトルの解析の結果、Ｎｏ．１の酸化物焼結体からはＺｎＩｎＦｅ酸化物の結晶粒は観察されなかった。一方、エネルギー分散型Ｘ線分光（ＥＤＸ）による元素分析では、表５に示すように、ＦｅはＺｎＩｎ酸化物の結晶粒にのみ含まれることが分かった。このことから、Ｆｅは、ＺｎＩｎ酸化物の結晶粒の結晶構造中に選択的に固溶していると考えられる。 As described above, as a result of the analysis of the X-ray diffraction spectrum, No. No crystal grains of ZnInFe oxide were observed from the oxide sintered body of No. 1. On the other hand, elemental analysis by energy dispersive X-ray spectroscopy (EDX) revealed that Fe was contained only in the crystal grains of the ZnIn oxide, as shown in Table 5. From this, it is considered that Fe is selectively dissolved in the crystal structure of the crystal grains of the ZnIn oxide.
（常圧焼結による酸化物焼結体の作製）
〔Ｎｏ．９～Ｎｏ．Ｎｏ．１４〕
　純度９９．９９％の酸化亜鉛粉末（ＺｎＯ）、純度９９．９９％の酸化インジウム粉末（Ｉｎ２Ｏ３）、純度９９．４％の酸化鉄粉末（Ｆｅ２Ｏ３）を表６に示す原子数比率で配合して原料粉末を得た。水と、ポリビニルアルコールを主成分とするバインダーと、アクリル系重合体を主成分とする分散剤とを加えて、ナイロンポッド及びメディアとしてジルコニアボールを使用したボールミルで３時間混合及び粉砕した。次に、得られた混合粉末を乾燥して造粒を行った。造粒後の混合粉末を成形型に入れ、冷間静水圧プレスで３ｔｏｎ／ｃｍ２で加圧して成形体を得た。この成形体を、常圧、大気雰囲気下で１５５０℃まで昇温し、２時間保持後、自然降温して焼結し、Ｎｏ．９～Ｎｏ．１４の酸化物焼結体を得た。Ｎｏ．９、Ｎｏ．１０及びＮｏ．１２について、走査型電子顕微鏡（ＳＥＭ）によって５０００倍で観察した反射電子像を図８～図１０に示す。 (Preparation of oxide sintered body by atmospheric pressure sintering)
[No. 9-No. No. 14]
Zinc oxide powder (ZnO) with a purity of 99.99%, indium oxide powder with a purity of 99.99% (In 2 O 3 ), and iron oxide powder with a purity of 99.4% (Fe 2 O 3 ) are shown in Table 6. Raw material powder was obtained by blending in several ratios. Water, a binder containing polyvinyl alcohol as a main component, and a dispersant containing an acrylic polymer as a main component were added, and the mixture was mixed and pulverized with a nylon pod and a ball mill using zirconia balls as a medium for 3 hours. Next, the obtained mixed powder was dried and granulated. The mixed powder after granulation was placed in a molding die and pressed at 3 ton / cm 2 with a cold hydrostatic press to obtain a molded product. This molded product was heated to 1550 ° C. under normal pressure and atmospheric atmosphere, held for 2 hours, naturally lowered to a temperature, and sintered. 9-No. 14 oxide sintered bodies were obtained. No. 9, No. 10 and No. The reflected electron images of No. 12 observed by a scanning electron microscope (SEM) at a magnification of 5000 are shown in FIGS. 8 to 10.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
〔結晶構造〕
　Ｎｏ．９、Ｎｏ．１０、Ｎｏ．１３及びＮｏ．１４について、Ｘ線回折スペクトルを解析し、結晶性評価を行った。Ｎｏ．９、Ｎｏ．１０、Ｎｏ．１３及びＮｏ．１４のＸ線回折スペクトルの解析結果を図１１～図１４に示す。なお、結晶性評価は、Ｘ線回折スペクトルのピークを各結晶粒の特定の結晶面に帰属させることで行った。 〔Crystal structure〕
No. 9, No. 10, No. 13 and No. The X-ray diffraction spectrum of No. 14 was analyzed and the crystallinity was evaluated. No. 9, No. 10, No. 13 and No. The analysis results of the X-ray diffraction spectrum of No. 14 are shown in FIGS. 11 to 14. The crystallinity evaluation was performed by assigning the peak of the X-ray diffraction spectrum to a specific crystal plane of each crystal grain.
　図１１に示すように、Ｎｏ．９は、Ｉｎ２Ｏ３結晶粒、Ｚｎ３Ｉｎ２Ｏ６結晶粒、Ｚｎ２Ｉｎ２Ｏ５結晶粒の３相から構成され、ＺｎＯ結晶粒は存在しないことが確認された。図１２に示すように、Ｎｏ．１０は、Ｉｎ２Ｏ３結晶粒及びＺｎ３Ｉｎ２Ｏ６結晶粒の２相から構成され、ＺｎＯ結晶粒は存在しないことが確認された。一方、Ｉｎの原子数に対するＺｎの原子数の比（Ｚｎ／Ｉｎ）が０．１０と小さいＮｏ．１３は、図１３に示すように、Ｉｎ２Ｏ３結晶粒及びＺｎ２Ｉｎ２Ｏ５結晶粒の２つの結晶粒が確認されており、ＺｎＩｎ酸化物の結晶粒がＺｎ２Ｉｎ２Ｏ５の結晶単相構造であることが分かった。また、Ｉｎの原子数に対するＺｎの原子数の比（Ｚｎ／Ｉｎ）が８．８１と大きいＮｏ．１４は、図１４に示すように、ＺｎＩｎ酸化物及びＩｎ２Ｏ３結晶粒を含まないＩｎ２Ｏ３（ＺｎＯ）１７という単相構造の結晶相から構成されていることが確認された。 As shown in FIG. 11, No. No. 9 was composed of three phases of In 2 O 3 crystal grains, Zn 3 In 2 O 6 crystal grains, and Zn 2 In 2 O 5 crystal grains, and it was confirmed that Zn O crystal grains did not exist. As shown in FIG. 12, No. No. 10 was composed of two phases of In 2 O 3 crystal grains and Zn 3 In 2 O 6 crystal grains, and it was confirmed that Zn O crystal grains did not exist. On the other hand, the ratio of the number of Zn atoms (Zn / In) to the number of In atoms is as small as 0.10. As shown in FIG. 13, in No. 13, two crystal grains of In 2 O 3 crystal grain and Zn 2 In 2 O 5 crystal grain were confirmed, and the crystal grain of Zn In oxide was Zn 2 In 2 O 5 . It was found to have a crystal single-phase structure. In addition, the ratio of the number of Zn atoms (Zn / In) to the number of In atoms is as large as 8.81. As shown in FIG. 14, it was confirmed that No. 14 was composed of a crystal phase having a single-phase structure of In 2 O 3 (ZnO) 17 containing no Zn In oxide and In 2 O 3 crystal grains.
〔Ｆｅの存在場所〕
　Ｎｏ．９、Ｎｏ．１０及びＮｏ．１２について、Ｉｎ酸化物の結晶粒（Ｉｎ２Ｏ３結晶単相構造）Ｘ、並びにＺｎＩｎ酸化物の結晶粒（Ｚｎ２Ｉｎ２Ｏ５結晶粒Ｙ１及びＺｎ３Ｉｎ２Ｏ６結晶粒Ｙ２）に対し、エネルギー分散型Ｘ線分光（ＥＤＸ）によって元素分析を行った。この分析結果を表７に示す。 [Location of Fe]
No. 9, No. 10 and No. For No. 12, the In oxide crystal grains (In 2 O 3 crystal single-phase structure) X and the Zn In oxide crystal grains (Zn 2 In 2 O 5 crystal grains Y1 and Zn 3 In 2 O 6 crystal grains Y2) On the other hand, elemental analysis was performed by energy dispersive X-ray spectroscopy (EDX). The results of this analysis are shown in Table 7.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　Ｘ線回折スペクトルの解析の結果、Ｎｏ．９、Ｎｏ．１０及びＮｏ．１２の酸化物焼結体からはＺｎＩｎＦｅ酸化物の結晶粒は観察されなかった。一方、エネルギー分散型Ｘ線分光（ＥＤＸ）による元素分析では、表７に示すように、ＦｅはＺｎＩｎ酸化物の結晶粒にのみ含まれることが分かった。このことから、Ｆｅは、ＺｎＩｎ酸化物の結晶粒の結晶構造中に選択的に固溶していると考えられる。 As a result of analysis of the X-ray diffraction spectrum, No. 9, No. 10 and No. No crystal grains of ZnInFe oxide were observed from the oxide sintered body of No. 12. On the other hand, elemental analysis by energy dispersive X-ray spectroscopy (EDX) revealed that Fe was contained only in the crystal grains of the ZnIn oxide, as shown in Table 7. From this, it is considered that Fe is selectively dissolved in the crystal structure of the crystal grains of the ZnIn oxide.
　なお、Ｎｏ．１１についても、Ｘ線回折スペクトルを解析し、Ｉｎ酸化物、酸化亜鉛及びＺｎＩｎ酸化物の結晶粒の結晶構造を求めたところ、Ｉｎ酸化物の結晶粒（Ｉｎ２Ｏ３結晶単相構造）及びＺｎＩｎ酸化物の結晶粒（Ｚｎ３Ｉｎ２Ｏ６結晶単相構造）の２相から構成され、ＺｎＯ結晶粒は存在しないことが確認された。Ｎｏ．１１についてエネルギー分散型Ｘ線分光（ＥＤＸ）によって元素分析を行った結果、ＦｅはＩｎ酸化物の結晶粒からは検出されない一方、積算時間を長くすることでＺｎＩｎ酸化物の結晶粒からは検出された。 In addition, No. As for No. 11, the X-ray diffraction spectrum was analyzed to determine the crystal structure of the crystal grains of In oxide, zinc oxide and ZnIn oxide. As a result, the crystal grains of In oxide (In 2 O 3 crystal single phase structure) and It was confirmed that it was composed of two phases of ZnIn oxide crystal grains (Zn 3 In 2 O 6 crystal single phase structure) and that ZnO crystal grains did not exist. No. As a result of elemental analysis of No. 11 by energy dispersive X-ray spectroscopy (EDX), Fe was not detected in the grain of In oxide, but was detected in the grain of ZnIn oxide by increasing the integration time. It was.
　以上説明したように、本発明の一態様に係る酸化物焼結体は、割れの発生を抑制できるので、スパッタリングターゲットとして好適に用いられる。 As described above, the oxide sintered body according to one aspect of the present invention can suppress the occurrence of cracks, and is therefore preferably used as a sputtering target.
１　酸化物焼結体
Ｘ　Ｉｎ酸化物の結晶粒
Ｙ、Ｙ１、Ｙ２　ＺｎＩｎ酸化物の結晶粒
Ｚ　空孔
Ｐ　酸化亜鉛の結晶粒 1 Oxide sintered body X In oxide crystal grains Y, Y1, Y2 ZnIn oxide crystal grains Z Pore P Zinc oxide crystal grains

Claims (9)

  1. 　Ｉｎ、Ｚｎ及びＦｅを含む酸化物焼結体であって、
    　酸化亜鉛（ＺｎＯ）の結晶粒を実質的に有さず、
    　Ｉｎ酸化物の結晶粒とＺｎＩｎ酸化物の結晶粒とを有し、
    　上記Ｉｎ酸化物の結晶粒がＦｅを実質的に含まないＩｎ２Ｏ３結晶単相構造であり、
    　上記ＺｎＩｎ酸化物の結晶粒がＦｅを含む酸化物焼結体。     An oxide sintered body containing In, Zn and Fe.
    It has virtually no zinc oxide (ZnO) crystal grains,
    It has In oxide crystal grains and ZnIn oxide crystal grains.
    The crystal grains of the In oxide have an In 2 O 3 crystal single-phase structure that does not substantially contain Fe.
    An oxide sintered body in which the crystal grains of the ZnIn oxide contain Fe.
  2. 　上記ＺｎＩｎ酸化物の結晶粒が、Ｚｎ２Ｉｎ２Ｏ５結晶単相構造ではない請求項１に記載の酸化物焼結体。 The oxide sintered body according to claim 1, wherein the crystal grains of the ZnIn oxide do not have a Zn 2 In 2 O 5 crystal single-phase structure.
  3. 　上記ＺｎＩｎ酸化物の結晶粒が、Ｚｎ３Ｉｎ２Ｏ６、Ｚｎ４Ｉｎ２Ｏ７及びＺｎ５Ｉｎ２Ｏ８の結晶構造の少なくともいずれか１つを有する請求項１に記載の酸化物焼結体。 The oxide sintering according to claim 1, wherein the crystal grains of the ZnIn oxide have at least one of the crystal structures of Zn 3 In 2 O 6 , Zn 4 In 2 O 7, and Zn 5 In 2 O 8. body.
  4. 　ＺｎＩｎＦｅ酸化物の結晶粒を実質的に有しない請求項１に記載の酸化物焼結体。 The oxide sintered body according to claim 1, which does not substantially have crystal grains of ZnInFe oxide.
  5. 　Ｉｎ、Ｚｎ及びＦｅの合計原子数に対し、
    　Ｉｎの原子数が４５ａｔｍ％以上８０ａｔｍ％以下、
    　Ｚｎの原子数が２０ａｔｍ％以上５５ａｔｍ％以下、
    　Ｆｅの原子数が０．１ａｔｍ％以上１．５ａｔｍ％以下
    　である請求項１に記載の酸化物焼結体。     For the total number of atoms of In, Zn and Fe
    The number of In atoms is 45 atm% or more and 80 atm% or less,
    The number of Zn atoms is 20 atm% or more and 55 atm% or less,
    The oxide sintered body according to claim 1, wherein the number of atoms of Fe is 0.1 atm% or more and 1.5 atm% or less.
  6. 　バルク抵抗が１×１０－２Ωｃｍ以下である請求項１に記載の酸化物焼結体。 The oxide sintered body according to claim 1, wherein the bulk resistance is 1 × 10 −2 Ωcm or less.
  7. 　相対密度が９６％以上である請求項１に記載の酸化物焼結体。 The oxide sintered body according to claim 1, which has a relative density of 96% or more.
  8. 　請求項１から請求項７のいずれか１項に記載の酸化物焼結体を有するスパッタリングターゲット。 A sputtering target having the oxide sintered body according to any one of claims 1 to 7.
  9. 　Ｉｎ、Ｚｎ及びＦｅを含むスパッタリングターゲットであって、
    　酸化亜鉛（ＺｎＯ）の結晶粒を実質的に有さず、
    　Ｉｎ酸化物の結晶粒とＺｎＩｎ酸化物の結晶粒とを有し、
    　上記Ｉｎ酸化物の結晶粒がＦｅを実質的に含まないＩｎ２Ｏ３結晶単相構造であり、
    　上記ＺｎＩｎ酸化物の結晶粒がＦｅを含むスパッタリングターゲット。     A sputtering target containing In, Zn and Fe.
    It has virtually no zinc oxide (ZnO) crystal grains,
    It has In oxide crystal grains and ZnIn oxide crystal grains.
    The crystal grains of the In oxide have an In 2 O 3 crystal single-phase structure that does not substantially contain Fe.
    A sputtering target in which the crystal grains of the ZnIn oxide contain Fe.
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Publication number Priority date Publication date Assignee Title
JPH0211209B2 (en) * 1982-01-29 1990-03-13 Yamada Kikai Kogyo Kk
WO2009081885A1 (en) * 2007-12-25 2009-07-02 Idemitsu Kosan Co., Ltd. Oxide semiconductor field effect transistor and method for manufacturing the same
WO2014112368A1 (en) * 2013-01-15 2014-07-24 出光興産株式会社 Sputtering target, oxide semiconductor thin film, and production methods for both
WO2017168906A1 (en) * 2016-03-28 2017-10-05 三井金属鉱業株式会社 Sputtering target material, manufacturing method therefor, and sputtering target
JP2018016495A (en) * 2016-07-25 2018-02-01 住友電気工業株式会社 Oxide sintered compact manufacturing method therefor, sputtering target and method for manufacturing semiconductor device
JP2019102793A (en) * 2017-11-29 2019-06-24 株式会社神戸製鋼所 Oxide semiconductor thin film, thin-film transistor and sputtering target

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Publication number Priority date Publication date Assignee Title
JPH0211209B2 (en) * 1982-01-29 1990-03-13 Yamada Kikai Kogyo Kk
WO2009081885A1 (en) * 2007-12-25 2009-07-02 Idemitsu Kosan Co., Ltd. Oxide semiconductor field effect transistor and method for manufacturing the same
WO2014112368A1 (en) * 2013-01-15 2014-07-24 出光興産株式会社 Sputtering target, oxide semiconductor thin film, and production methods for both
WO2017168906A1 (en) * 2016-03-28 2017-10-05 三井金属鉱業株式会社 Sputtering target material, manufacturing method therefor, and sputtering target
JP2018016495A (en) * 2016-07-25 2018-02-01 住友電気工業株式会社 Oxide sintered compact manufacturing method therefor, sputtering target and method for manufacturing semiconductor device
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