US20160293412A1 - Sputtering target, oxide semiconductor thin film, and method for producing these - Google Patents

Sputtering target, oxide semiconductor thin film, and method for producing these Download PDF

Info

Publication number
US20160293412A1
US20160293412A1 US14/442,686 US201314442686A US2016293412A1 US 20160293412 A1 US20160293412 A1 US 20160293412A1 US 201314442686 A US201314442686 A US 201314442686A US 2016293412 A1 US2016293412 A1 US 2016293412A1
Authority
US
United States
Prior art keywords
thin film
sputtering
oxide semiconductor
oxide
sputtering target
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US14/442,686
Other languages
English (en)
Inventor
Kazuaki Ebata
Nozomi Tajima
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Idemitsu Kosan Co Ltd
Original Assignee
Idemitsu Kosan Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Idemitsu Kosan Co Ltd filed Critical Idemitsu Kosan Co Ltd
Assigned to IDEMITSU KOSAN CO., LTD. reassignment IDEMITSU KOSAN CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: EBATA, KAZUAKI, TAJIMA, Nozomi
Publication of US20160293412A1 publication Critical patent/US20160293412A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02551—Group 12/16 materials
    • H01L21/02554—Oxides
    • 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
    • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
    • 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
    • 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
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C23C14/08—Oxides
    • 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
    • C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
    • C23C14/3414—Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
    • 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
    • C23C14/35—Sputtering by application of a magnetic field, e.g. magnetron sputtering
    • C23C14/352—Sputtering by application of a magnetic field, e.g. magnetron sputtering using more than one target
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02565—Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/02631—Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/22—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only AIIBVI compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409—Unipolar field-effect transistors
    • H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/66742—Thin film unipolar transistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66969—Multistep manufacturing processes of devices having semiconductor bodies not comprising group 14 or group 13/15 materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/786—Thin film transistors, i.e. transistors with a channel being at least partly a thin film
    • H01L29/7869—Thin film transistors, i.e. transistors with a channel being at least partly a thin film having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3284—Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • 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
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3293—Tin oxides, stannates or oxide forming salts thereof, e.g. indium tin oxide [ITO]
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5445—Particle size related information expressed by the size of the particles or aggregates thereof submicron sized, i.e. from 0,1 to 1 micron
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
    • C04B2235/6562—Heating rate
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
    • C04B2235/6565—Cooling rate
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
    • C04B2235/6567—Treatment time
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/77—Density
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/80—Phases present in the sintered or melt-cast ceramic products other than the main phase

Definitions

  • the invention relates to a sputtering target, a thin film prepared by using the target and a thin film transistor that comprises the thin film.
  • Field effect transistors such as a thin film transistor (TFT) are widely used as the unit electronic device of a semiconductor memory integrated circuit, a high frequency signal amplification device, a device for driving a liquid crystal, or the like, and they are electronic devices which are currently most widely put into practical use.
  • TFT thin film transistor
  • LCD liquid crystal display
  • EL electroluminescence display
  • FED field emission display
  • a silicon semiconductor compound As a material of a semiconductor layer (channel layer) which is a main element of a field effect transistor, a silicon semiconductor compound is used most widely. Generally, a silicon single crystal is used for a high frequency amplification device, a device for integrated circuits or the like which need high-speed operation. On the other hand, an amorphous silicon semiconductor (amorphous silicon) is used for a device for driving a liquid crystal or the like in order to satisfy the demand for realizing a large-area display.
  • a thin film of amorphous silicon can be formed at relatively low temperatures.
  • the switching speed thereof is slow as compared with that of a crystalline thin film. Therefore, when it is used as a switching device that drives a display, it may be unable to follow the display of a high-speed animation.
  • amorphous silicon having a mobility of 0.5 to 1 cm 2 Ns could be used in a liquid crystal television of which the resolution is VGA.
  • the resolution is equal to or more than SXGA, UXGA and QXGA, a mobility of 2 cm 2 Ns or more is required.
  • the driving frequency is increased in order to improve the image quality, a further higher mobility is required.
  • a crystalline silicon-based thin film although it has a high mobility, there are problems that a large amount of energy and a large number of steps are required for the production, and that large-area film formation is difficult.
  • a silicon-based thin film is crystallized, a high temperature of 800° C. or more or laser annealing which needs expensive equipment is required.
  • the device configuration of a TFT is normally restricted to a top-gate configuration, and hence, reduction in production cost such as decrease in number of masks is difficult.
  • an oxide semiconductor thin film is formed by sputtering using a target (sputtering target) composed of an oxide sintered body.
  • Patent Documents 1, 2 and 3 a target formed of a compound showing a homologous crystal structure such as that represented by a general formulas In 2 Ga 2 ZnO 7 and InGaZnO 4 is known (Patent Documents 1, 2 and 3).
  • sintering density relative density
  • it is required to conduct sintering in an oxidizing atmosphere.
  • a reduction treatment at a high temperature is required to be conducted after sintering.
  • Patent Document 4 a thin film transistor that is obtained by using an amorphous oxide semiconductor film that does not contain gallium and is composed of indium oxide and zinc oxide has been proposed (Patent Document 4).
  • this thin film transistor has a problem that a normally-off operation of a TFT cannot be realized if the oxygen partial pressure at the time of film formation is not increased.
  • Patent Documents 5 and 6 studies have been made on a sputtering target for forming a protective layer of an optical information recording medium, that is obtained by adding an additive element such as Ta, Y, Si or the like to an In 2 O 3 —SnO 2 —ZnO-based oxide composed mainly of tin oxide.
  • these targets are not used for forming an oxide semiconductor and they have problems that an agglomerate of an insulating material is likely to be formed easily, whereby the resistance is increased or abnormal discharge tends to occur easily.
  • Patent Document 1 JP-A-H08-245220
  • Patent Document 2 JP-A-2007-73312
  • Patent Document 3 WO2009/084537
  • Patent Document 4 WO2005/088726
  • Patent Document 5 WO2005/078152
  • Patent Document 6 WO2005/078153
  • An object of the invention is to provide a high-density and low-resistant sputtering target.
  • Another object of the invention is to provide a thin film transistor having a high field effect mobility and high reliability.
  • a sputtering target comprising an oxide that contains an indium (In) element, a tin (Sn) element, a zinc (Zn) element and an aluminum (Al) element and comprising a homologous structure compound represented by InAlO 3 (ZnO) m (m is 0.1 to 10) and a bixbyite structure represented by In 2 O 3 has a high relative density and has a low resistance.
  • a TFT using a thin film obtained by using this target in a channel layer has a high field effect mobility and has a high reliability. The invention has been completed based on these findings.
  • the following sputtering target or the like are provided.
  • a sputtering target comprising an oxide that comprises an indium (In) element, a tin (Sn) element, a zinc (Zn) element and an aluminum (Al) element, wherein the oxide comprises a homologous structure compound represented by InAlO 3 (ZnO) m (m is 0.1 to 10) and a bixbyite structure compound represented by In 2 O 3 .
  • the sputtering target according to 1, wherein the homologous structure compound is one or more selected from homologous structure compounds represented by InAlZn 4 O 7 , InAlZn 3 O 6 , InAlZn 2 O 5 and InAlZnO 2 .
  • a method for producing an oxide semiconductor thin film wherein the film is formed by a sputtering method with the use of the sputtering target according to any one of 1 to 6 in an atmosphere of a mixed gas that comprises: one or more selected from water vapor, an oxygen gas and a nitrous oxide gas; and a rare gas.
  • a mixed gas that comprises: one or more selected from water vapor, an oxygen gas and a nitrous oxide gas; and a rare gas.
  • a thin film transistor comprising, as a channel layer, the oxide semiconductor thin film formed by the method for producing an oxide semiconductor thin film according to any one of 8 to 13.
  • FIG. 1 is a view showing a sputtering apparatus used in one embodiment of the invention
  • FIG. 2 is a view showing an X-ray diffraction chart of a sintered body obtained in Example 1;
  • FIG. 3 is a view showing an X-ray diffraction chart of a sintered body obtained in Example 2;
  • FIG. 4 is a view showing an X-ray diffraction chart of a sintered body obtained in Example 3;
  • FIG. 5 is a view showing an X-ray diffraction chart of a sintered body obtained in Example 4.
  • FIG. 6 is a view showing an X-ray diffraction chart of a sintered body obtained in Example 5.
  • FIG. 7 is a view showing an X-ray diffraction chart of a sintered body obtained in Example 6.
  • the sputtering target of the invention comprises an oxide that contains an indium (In) element, a tin (Sn) element, a zinc (Zn) element and an aluminum (Al) element, and is characterized in that it comprises a homologous structure compound represented by InAlO 3 (ZnO) m (m is 0.1 to 10) and a bixbyite structure represented by In 2 O 3 .
  • the target due to the presence of the homologous structure compound and the bixbyite structure compound mentioned above, the target has a high relative density and a low bulk resistance. Therefore, occurrence of abnormal discharge can be suppressed when sputtering is conducted using the target of the invention. Further, the target of the invention can form a high-quality oxide semiconductor thin film efficiently, at a low cost and with a small energy.
  • the homologous structure compound represented by InAlO 3 (ZnO) m (m is 0.1 to 10) can be confirmed by the fact that a peak derived from the homologous structure compound can be observed as a result of an X-ray diffraction analysis of the target (oxide sintered body).
  • m is 0.1 to 10
  • m is 0.1 to 10, preferably 0.5 to 8, and further preferably 1 to 7.
  • m is preferably an integer.
  • the homologous structure compound represented by InAlO 3 (ZnO) m is preferably one or more selected from homologous structure compounds represented by InAlZn 4 O 7 , InAlZn 3 O 6 , InAlZn 2 O 5 and InAlZnO 2 .
  • the homologous crystal structure is a crystal structure formed of a long-period “natural superlattice” structure in which crystal layers of different substances are stacked. If the crystal period or the thickness of each thin film layer is on an about nanometer level, a homologous structure compound can exhibit inherent characteristics that differ from the characteristics of a single substance or a mixed crystal in which the layers are uniformly mixed depending on combination of the chemical composition or the thickness of each layer.
  • the crystal structure of the homologous phase can be confirmed by a fact that an X-ray diffraction pattern measured from powder obtained by pulverizing the target coincident with an X-ray diffraction pattern of the crystal structure of the homologous phase assumed from the composition ratio. Specifically, it can be confirmed that the pattern is coincident with the crystal structure X-ray diffraction pattern of the homologous phase obtained from the JCPDS (Joint Committee of Powder Diffraction Standards) card or the ICSD (The Inorganic Crystal Structure Database).
  • JCPDS Joint Committee of Powder Diffraction Standards
  • ICSD The Inorganic Crystal Structure Database
  • RAO 3 (MO) m As the oxide crystal having a homologous crystal structure, an oxide crystal represented by RAO 3 (MO) m can be mentioned.
  • R and A are each a positive trivalent metal element, and as examples thereof, In, Ga, Al, Fe, B or the like can be mentioned, for example.
  • A is a positive trivalent metal element that is different from R, and as examples thereof, Ga, Al, Fe or the like can be mentioned, for example.
  • M is a positive divalent metal element, and as examples thereof, Zn, Mg or the like can be mentioned, for example.
  • InAlO 3 (ZnO) m (m is 0.1 to 10) of the invention R is In, A is Al and M is Zn.
  • the homologous structure represented by InAlZnO 2 shows a peak pattern of No. 40-0258 of JCPDS database or a similar (shifted) pattern.
  • the homologous structure represented by InAlZn 2 O 5 shows a peak pattern of No. 40-0259 of JCPDS database or a similar (shifted) pattern.
  • the homologous structure represented by InAlZn 3 O 6 shows a peak pattern of No. 40-0260 of JCPDS database or a similar (shifted) pattern.
  • the homologous structure represented by InAlZn 4 O 7 shows a peak pattern of 40-0261 of JCPDS database or a similar (shifted) pattern.
  • the bixbyite structure compound represented by In 2 O 3 can be confirmed by a fact that the peak derived from the bixbyite structure compound is observed by an X-ray diffraction analysis of the target.
  • the bixbyite structure compound represented by In 2 O 3 shows a peak pattern of No. 06-0416 of JCPDS database or a similar (shifted) pattern.
  • the bixbyite is also referred to as a C-type rare-earth oxide or Mn 2 O 3 (I) type oxide.
  • Mn 2 O 3 (I) type oxide As stated in the “Technology of Transparent Conductive Film” (published by Ohmsha Ltd., edited by Japan Society for the Promotion of Science, transparent oxide/photoelectron material 166 committee, 1999) or the like, this compound has a chemical stoichiometric ratio of M 2 X 3 (M is a cation and X is an anion, which is normally an oxygen ion), and one unit cell is formed of 16 M 2 X 3 molecules and 80 atoms in total (the number of M is 32 and the number of X is 48).
  • the bixbyite structure compound includes a substitutional solid solution in which part of atoms or ions in a crystal structure are replaced by other atoms and an interstitial solid solution in which other atoms are added to a position between lattices.
  • the sputtering target of the invention preferably does not comprise a spinel structure compound represented by Zn 2 SnO 4 .
  • the spinel structure compound represented by Zn 2 SnO 4 shows a peak pattern of No. 24-1470 of JCPDS database or a similar (shifted) pattern in an X-ray diffraction.
  • the spinel structure normally means AB 2 X 4 type or A 2 BX 4 type structure, and a compound having such a crystal structure is referred to as a spinel structure compound.
  • cations normally, oxygen
  • anions are present in part of the tetrahedral interstitial site or the octahedral interstitial site thereof.
  • a substitutional solid solution in which a part of atoms or ions in a crystal structure are replaced by other atoms and an interstitial solid solution in which other atoms are added to a position between lattices are included in a spinel structure compound.
  • the target comprises a spinel structure compound represented by Zn 2 SnO 4 in addition to the homologous structure compound represented by InAlO 3 (ZnO) m (m is 0.1 to 10) and a bixbyite structure compound represented by In 2 O 3 , the sputtering speed varies depending on the crystal phase since a large amount of different phases are present in the oxide sintered body constituting the target, and hence, parts remaining unremoved may be formed.
  • an indium element, a tin element, a zinc element and an aluminum element satisfy the following formulas (1) to (4):
  • the atomic ratio of In if the atomic ratio of In is 0.10 or more, the bulk resistance of the sputtering target does not increase too high, whereby DC sputtering can be conducted without problems.
  • the atomic ratio of In if the atomic ratio of In is 0.75 or less, the homologous structure compound represented by InAlO 3 (ZnO) m (m is 0.1 to 10) and the bixbyite structure compound represented by In 2 O 3 tend to be formed easily in the target. If both of the homologous structure compound represented by InAlO 3 (ZnO) m (m is 0.1 to 10) and the bixbyite structure compound represented by In 2 O 3 are formed, abnormal grain growth of crystals in the oxide and abnormal discharge caused by the abnormal grain growth can be prevented.
  • the atomic ratio of the In element [In/(In+Sn+Zn+Al)] be 0.10 to 0.75, more preferably 0.20 to 0.70, and further preferably 0.25 to 0.70.
  • the atomic ratio of the Sn element is 0.01 or more, the density of the oxide sintered body that constitutes the target sufficiently increases, whereby the bulk resistance of the target is lowered.
  • the atomic ratio of the Sn element is 0.30 or less, SnO 2 that causes abnormal discharge to occur is suppressed, whereby abnormal discharge can be prevented.
  • the atomic ratio of the Sn element is preferably 0.01 to 0.30, more preferably 0.03 to 0.25, and further preferably 0.05 to 0.15.
  • the atomic ratio of the Zn element is preferably 0.10 to 0.70, more preferably 0.20 to 0.65, and further preferably 0.25 to 0.60.
  • the atomic ratio of the Al element is preferably 0.01 to 0.40, more preferably 0.02 to 0.30, and further preferably 0.05 to 0.25.
  • the atomic ratio of elements contained in the sintered body can be obtained by quantitatively analyzing the elements contained with Induction Coupled Plasma Atomic Emission Spectrometry (ICP-AES).
  • ICP-AES Induction Coupled Plasma Atomic Emission Spectrometry
  • each element contained in the sample absorbs thermal energy, and is excited, and the orbital electrons migrate from the ground state to the orbital at a high energy level.
  • the orbital electrons then migrate to the orbital at a lower energy level when about 10 ⁇ 7 to about 10 ⁇ 8 seconds have elapsed.
  • the difference in energy is emitted as light. Since the emitted light has an element-specific wavelength (spectral line), the presence or absence of each element can be determined based on the presence or absence of the spectral line (qualitative analysis).
  • the element concentration in the sample can be determined by comparison with a standard solution having a known concentration (quantitative analysis).
  • the content of each element is determined by quantitative analysis, and the atomic ratio of each element is calculated from the results.
  • the sputtering target of the invention may comprise other metal elements than In, Sn, Zn and Al as long as the effects of the invention are not impaired.
  • the sputtering target may consist essentially of In, Sn, Zn and Al or may consist of In, Sn, Zn and Al.
  • the “essentially” means that 95 mass % or more and 100 mass % or less (preferably 98 mass % or more and 100 mass % or less) of the metal element of the sputtering target is In, Sn, Zn and Al.
  • the sputtering target of the invention may contain impurities that are inevitably mixed in addition to In, Sn, Zn and Al in a range that does not impair the advantageous effects of the invention.
  • the sputtering target of the invention have a relative density of 98% or more.
  • the relative density be 98% or more.
  • the relative density is a density which is relatively calculated for the theoretical density which is calculated from the weighted average.
  • the density calculated from the weighted average of the density of each raw material is a theoretical density, which is assumed to be 100%.
  • the relative density is 98% or more, stable sputtering state is maintained.
  • the film is formed by increasing the sputtering power on a large substrate, if the sputtering target has a relative density 98% or more, the target surface is not be blackened easily or abnormal discharge does not occur easily.
  • the relative density is preferably 98.5% or more, with 99% or more being more preferable.
  • the relative density of the target can be measured by the Archimedian method.
  • the relative density is preferably 100% or less. If the relative density is 100% or less, metal particles are not be generated easily in a sintered body, and formation of a lower oxide is suppressed. Therefore, it is not required to control the oxygen supply amount during film-formation strictly.
  • the density can be adjusted by a post treatment or the like such as a heat treatment in the reductive atmosphere after sintering.
  • a post treatment or the like such as a heat treatment in the reductive atmosphere after sintering.
  • an atmosphere such as argon, nitrogen and hydrogen, or an atmosphere of a mixture of these gases can be used.
  • the maximum particle size of the crystal in the oxide constituting the sputtering target be 8 ⁇ m or less. Due to the crystal particle size of 8 ⁇ m or less, formation of nodules can be suppressed.
  • the grinding speed differs depending on the direction of the crystal, whereby unevenness is generated on the target surface.
  • the size of this unevenness varies depending on the particle size of the crystal present in the sintered body. It is assumed that, in the target formed of a sintered body having a large crystal particle size, a greater scale of unevenness occurs, and nodules are generated from this convex part.
  • the maximum particle size of the crystal of the sputtering target is obtained as follows. If the sputtering target has a circular shape, at five locations in total, i.e. the central point (one) and the points (four) which are on two central lines crossing orthogonally at this central point and are middle between the central point and the peripheral part, or if the sputtering target has a square shape, at five locations in total, i.e. the central point (one) and middle points (four) between the central point and the corners of the diagonal lines of the square, the maximum diameter is measured for the biggest particle observed within a 100- ⁇ m square. The maximum particle size is the average value of the maximum diameters of the biggest particle present in each of the frames defined by the five locations. As for the particle size, the longer diameter of the crystal particle is measured. The crystal particles can be observed by the scanning electron microscopy (SEM).
  • the bulk specific resistance is preferably 10 m ⁇ cm or less, more preferably 8 m ⁇ cm or less, with 5 m ⁇ cm or less being particularly preferable.
  • the bulk specific resistance can be measured by the method described in the Examples.
  • the relative density of the target can be 98% or more and the bulk resistance can be 10 m ⁇ cm or less by adjusting the content of the indium (In) element, the tin (Sn) element, the zinc (Zn) element and the aluminum (Al) element to be in the above-mentioned ranges (1) to (4).
  • the method for producing a sputtering target of the invention comprises the following two steps, for example:
  • the raw material compounds may be a simple substance or a compound of In, Sn, Zn and Al. It is preferable to use a simple substance or a compound such that the sintered body can have an atomic ratio shown in the following formulas (1) to (4):
  • a combination of indium oxide, tin oxide, zinc oxide and aluminum metal, a combination of indium oxide, tin oxide, zinc oxide and aluminum oxide or the like can be mentioned. It is preferred that the raw material be powder. It is preferred that the raw material be a mixed powder of indium oxide, tin oxide, zinc oxide and aluminum oxide.
  • metal particles of aluminum may be present in the resulting sintered body.
  • metal particles on the target surface may be molten during film formation and hence may not be emitted from the target, resulting in a great difference between the composition of the film and the composition of the sintered body.
  • the average particle diameter of the raw material powder is preferably 0.1 ⁇ m to 1.2 ⁇ m, more preferably 0.1 ⁇ m to 1.0 ⁇ m.
  • the average particle diameter of the raw material powder can be measured by a laser diffraction particle size distribution measuring apparatus or the like.
  • In 2 O 3 powder having an average particle diameter of 0.1 ⁇ m to 1.2 ⁇ m, SnO 2 powder having an average particle diameter of 0.1 ⁇ m to 1.2 ⁇ m, ZnO powder having an average particle diameter of 0.1 ⁇ m to 1.2 ⁇ m and Al 2 O 3 powder having an average particle diameter of 0.1 ⁇ m to 1.2 ⁇ m are used as the raw material powder. They are mixed in an amount ratio that satisfies the above-mentioned formulas (1) to (4).
  • the method for forming is not particularly restricted, and a known method can be used.
  • a water-based solvent is added to raw material powders including indium oxide powder, tin oxide powder, zinc oxide powder and aluminum oxide powder, and the resulting slurry is mixed for 12 hours or more. Then, the mixture is subjected to solid-liquid separation, dried and granulated, and the granulated product is then put in a mold and formed.
  • a wet or dry ball mill, a vibration mill, a beads mill or the like can be used.
  • the most preferable method is a beads mill mixing method since it can pulverize the aggregate efficiently for a short period of time and can realize a favorable dispersed state of additives.
  • the mixing time is preferably 15 hours or longer, more preferably 19 hours or longer. If the mixing time is 15 hours or longer, a high-resistant compound such as Al 2 O 3 may not be generated easily in the oxide sintered body finally obtained.
  • the mixing time varies depending on the size of the apparatus used and the amount of slurry to be treated. However, the mixing time is controlled appropriately such that the particle distribution in the slurry becomes uniform, i.e. all of the particles have a particle size of 1 ⁇ m or less.
  • binder polyvinyl alcohol, vinyl acetate or the like can be used.
  • granulated powder is obtained from a raw material powder slurry.
  • quick dry granulation it is preferable to use quick dry granulation.
  • a spray dryer is widely used as the apparatus for quick dry granulation. Specific drying conditions are determined according to conditions such as the concentration of slurry to be dried, the temperature of hot air used for drying and the amount of wind. For actually conducting the quick dry granulation, it is required to obtain optimum conditions in advance.
  • a homogenous granulated powder can be obtained. That is, separation of In 2 O 3 powder, SnO 2 powder, ZnO powder and Al 2 O 3 powder due to difference in speed of sedimentation caused by the difference in specific gravity of the raw material powder can be prevented. If a sintered body is made by using uniform granulated powder, abnormal discharge during sputtering due to the presence of Al 2 O 3 or the like within the sintered body can be prevented.
  • the granulated powder can normally be formed into a formed body by pressing at a pressure of 1.2 ton/cm 2 or more, for example, by means of a mold press or cold isostatic pressing (CIP).
  • a pressure of 1.2 ton/cm 2 or more for example, by means of a mold press or cold isostatic pressing (CIP).
  • the resulting formed body is sintered at 1200 to 1650° C. for 10 to 50 hours to obtain a sintered body.
  • the sintering temperature is preferably 1350 to 1600° C., more preferably 1400 to 1600° C., and further preferably 1450 to 1600° C.
  • the sintering time is preferably 12 to 40 hours, more preferably 13 to 30 hours.
  • the sintering temperature is 1200° C. or more and the sintering time is 10 hours or longer, formation of Al 2 O 3 or the like within the target can be suppressed, whereby abnormal discharge can preferably be prevented.
  • the calcination temperature is 1650° C. or lower or the calcination time is 50 hours or shorter, an increase in average crystal diameter due to significant crystal particle growth can be prevented.
  • generation of large voids can be suppressed, lowering in strength of a sintered body or occurrence of abnormal discharge can preferably be prevented.
  • a pressure sintering method such as hot pressing, oxygen pressurization and hot isostatic pressing or the like can be used.
  • a pressure sintering method such as hot pressing, oxygen pressurization and hot isostatic pressing or the like.
  • a formed body is sintered in the air or the oxidizing gas atmosphere.
  • a formed body is sintered in the oxidizing gas atmosphere.
  • the oxidizing gas atmosphere is preferably an oxygen gas atmosphere. It is preferred that the oxygen gas atmosphere be an atmosphere having an oxygen concentration of 10 to 100 vol %, for example.
  • the density of the sintered body can be further increased by introducing an oxygen gas atmosphere during the temperature-elevating step.
  • the temperature-elevating rate at the time of sintering it is preferred that the temperature-elevating rate be 0.1 to 2.5° C./min in a temperature range of from 800° C. to a sintering temperature (1200 to 1650° C.).
  • a temperature range of from 800° C. and higher is a range where sintering proceeds most quickly. If the temperature-elevating rate in this temperature range is 0.1° C./min or more, excessive growth of crystal particles can be prevented, whereby an increase in density can be attained. On the other hand, if the temperature-elevating rate is 2.5° C./min or less, deposition of Al 2 O 3 or the like within the target can preferably be prevented.
  • the temperature-elevating rate from 800° C. to a sintering temperature is preferably 0.1 to 2.0° C./min, more preferably 0.1 to 1.5° C./min.
  • the temperature-decreasing rate (cooling rate) during calcination is normally 10° C./min or less, preferably 9° C./min or less, more preferably 8° C./min or less, further preferably 7° C./min or less, and particularly preferably 5° C./min or less. If the temperature-decreasing rate is 10° C./min or less, the crystal form of the invention can be obtained easily. In addition, cracks hardly occur during temperature decreasing.
  • a reduction step may be further provided, if necessary.
  • a reduction treatment by a reductive gas a reduction treatment by vacuum calcination, a reduction treatment by an inert gas or the like can be given, for example.
  • the temperature at the time of the above-mentioned reduction treatment is normally 100 to 800° C., preferably 200 to 800° C.
  • the reduction treatment is conducted normally for 0.01 to 10 hours, preferably 0.05 to 5 hours.
  • a water-based solvent is compounded with raw material powders containing mixed powder of indium oxide power, zinc oxide powder and aluminum oxide powder to obtain a slurry.
  • the obtained slurry is then mixed for 12 hours or longer, and is subjected to solid-liquid separation, dried and granulated.
  • the granulated product is put in a mold and formed.
  • the resulting formed body is sintered at 1200 to 1650° C. for 10 to 50 hours with a temperature-elevating rate in a temperature range of from 800° C.
  • the sintered body of the invention can be obtained.
  • the sputtering target of the invention can be obtained. Specifically, by grinding the sintered body into a shape suited to be mounted in a sputtering apparatus, a sputtering target (target material) is obtained. If necessary, the sputtering target material may be bonded to a backing plate to obtain a sputtering target.
  • the sintered body is ground by means of a surface grinder to allow the surface roughness Ra to be 0.5 ⁇ m or less. Further, the sputtering surface of the target material may be subjected to mirror finishing, thereby allowing the average surface roughness thereof Ra to be 1000 ⁇ or less.
  • polishing techniques such as mechanical polishing, chemical polishing, mechano-chemical polishing (combination of mechanical polishing and chemical polishing) or the like may be used.
  • it can be obtained by polishing by means of a fixed abrasive polisher (polishing liquid: water) to attain a roughness of #2000 or more, or can be obtained by a process in which, after lapping by a free abrasive lap (polisher: SiC paste or the like), lapping is conducted by using diamond paste as a polisher instead of the SiC paste.
  • polishing liquid polisher
  • SiC paste free abrasive lap
  • the surface roughness Ra of the target material be 0.5 ⁇ m or less and that the grinding surface have no directivity. If Ra is 0.5 ⁇ m or less and the grinding surface has no directivity, occurrence of abnormal discharge or generation of particles can preferably be prevented.
  • the thus processed target material is subjected to a cleaning treatment.
  • a cleaning treatment For cleaning, air blowing, washing with running water or the like can be used.
  • foreign matters When foreign matters are removed by air blowing, foreign matters can be removed more effectively by air intake by means of a dust collector from the side opposite from the nozzle.
  • ultrasonic cleaning or the like can also be conducted.
  • ultrasonic cleaning it is effective to conduct multiplex oscillation within a frequency range of 25 to 300 KHz.
  • the thickness of the target material is normally 2 to 20 mm, preferably 3 to 12 mm, and particularly preferably 4 to 6 mm.
  • a sputtering target By bonding the target material obtained in the manner as mentioned above to a backing plate, a sputtering target can be obtained.
  • a plurality of target materials may be provided in a single backing plate to be used as a substantially single target.
  • the oxide semiconductor thin film of the invention can be obtained.
  • the oxide semiconductor thin film of the invention is composed of indium, tin, zinc, aluminum and oxygen and preferably satisfies the following atomic ratios (1) to (4):
  • the atomic ratio of the In element is 0.10 or more, the degree of overlapping of the In 5s orbital can be kept large, and as a result, the field effect mobility may be 10 cm 2 Ns or more easily.
  • the atomic ratio of the In element 0.75 or less good reliability can be obtained if the formed film is applied to a channel layer of a TFT
  • the atomic ratio of the Sn element if the atomic ratio of the Sn element is 0.01 or more, an increase in target resistance can be suppressed, and film formation can be stabilized easily since abnormal discharge hardly occurs during sputtering. On the other hand, if the atomic ratio of the Sn element is 0.30 or less, lowering in solubility of the resulting thin film in a wet etchant can be prevented, whereby wet etching can be conducted without problems.
  • the resulting film can be stable as an amorphous film.
  • the amount of the Zn element is 0.70 or less, since the dissolution speed of the resulting thin film in a wet etchant is not too high, resulting in smooth wet etching.
  • the atomic ratio of the Al element is 0.01 or more, an increase in the oxygen partial pressure during film formation can be prevented. Since the Al element is bonded to oxygen strongly, it can lower the oxygen partial pressure during film formation. Further, when a channel layer is formed and applied to a TFT, good reliability cab be obtained. On the other hand, if the atomic ratio of the Al element is 0.40 or less, occurrence of abnormal discharge due to formation of Al 2 O 3 at the time of film formation by sputtering can be prevented, leading to stable film formation.
  • the carrier concentration of the oxide semiconductor thin film is normally 10 19 /cm 3 or less, preferably 10 13 to 10 18 /cm 3 , further preferably 10 14 to 10 18 /cm 3 , and particularly preferably 10 15 to 10 18 /cm 3 .
  • the carrier concentration of the oxide layer is 10 19 cm 3 or less, it is possible to prevent current leakage, normally-on, lowering in on-off ratio when a device such as a thin film transistor is fabricated. As a result, good transistor performance can be exhibited. Further, if the carrier concentration is 10 13 cm 3 or more, the device can be driven as a TFT without causing problems.
  • the carrier concentration of the oxide semiconductor thin film can be measured by the Hall effect measurement. Specifically, it can be measured by the methods described in the Examples.
  • a DC sputtering method having a high film-forming speed can be applied to the sputtering target of the invention.
  • the RF sputtering method, the AC sputtering method and the pulse DC sputtering method can be applied to the sputtering target of the invention, and sputtering free from abnormal discharge can be conducted.
  • the oxide semiconductor thin film can also be formed by using the above-mentioned sintered body by the deposition method, the ion-plating method, the pulse laser deposition method or the like in addition to the sputtering method.
  • a mixed gas of a rare gas such as argon and an oxidizing gas can be used.
  • the oxidizing gas include O 2 , CO 2 , O 3 , H 2 O and N 2 O.
  • a mixed gas containing a rare gas, and one or more gases selected from water vapor, an oxygen gas and a nitrous oxide gas is preferable.
  • a mixed gas containing a rare gas and at least water vapor is more preferable.
  • the oxygen partial pressure ratio at the time of film formation by sputtering is preferably 0% or more and less than 40%.
  • a thin film formed under the conditions in which the oxygen partial pressure ratio is less than 40% may not have a significantly decreased carrier concentration. As a result, it becomes possible to prevent the carrier concentration from being less than 10 13 cm 3 .
  • the oxygen partial pressure ratio is preferably 0% to 30% and particularly preferably 0% to 20%.
  • the partial pressure ratio of water vapor contained in a sputtering gas (atmosphere) at the time of depositing an oxide thin film in the invention i.e. [H 2 O]/([H 2 O]+[rare gas]+[other gases]), is preferably 0.1 to 25%. If the water partial pressure is 25% or less, it is possible to prevent a decrease in film density, and as a result, the degree of overlapping of the In 5s orbital can be kept large, whereby lowering in mobility can be prevented.
  • the partial pressure ratio of water in the atmosphere at the time of sputtering is more preferably 0.7 to 13%, with 1 to 6% being particularly preferable.
  • the substrate temperature at the time of film formation by sputtering is preferably 25 to 120° C., further preferably 25 to 100° C., and particularly preferably 25 to 90° C.
  • the substrate temperature at the time of film formation is 120° C. or less, oxygen or the like can be incorporated sufficiently at the time of film formation, whereby an excessive increase in carrier concentration of the thin film after heating can be prevented. Further, if the substrate temperature at the time of film formation is 25° C. or more, the denseness of the thin film may not be lowered, and as a result, lowering in mobility of a TFT can be prevented.
  • the oxide thin film obtained by sputtering be further subjected to an annealing treatment by retaining at 150 to 500° C. for 15 minutes to 5 hours.
  • the annealing treatment temperature after film formation is more preferably 200° C. or more and 450° C. or less, further preferably 250° C. or more and 350° C. or less.
  • the heating atmosphere is not particularly restricted. In respect of carrier control properties, the air atmosphere or the oxygen-circulating atmosphere is preferable.
  • a lamp annealing apparatus in the presence or absence of oxygen, a lamp annealing apparatus, a laser annealing apparatus, a thermal plasma apparatus, a hot air heating apparatus, a contact heating apparatus or the like can be used.
  • the distance between the target and the substrate at the time of sputtering is preferably 1 to 15 cm in a direction perpendicular to the film-forming surface of the substrate, with 2 to 8 cm being further preferable.
  • this distance is 1 cm or more, the kinetic energy of particles of target-constituting elements which arrive at the substrate can be prevented from becoming excessively large, and hence, good film properties can be obtained. Further, in-plane distribution or the like of the film thickness and the electric characteristics can be prevented.
  • the distance between the target and the substrate is 15 cm or less, the kinetic energy of particles of target-constituting elements can be prevented from becoming too small, and a dense film may be obtained, and as a result, good semiconductor properties can be obtained.
  • the formation of an oxide thin film it is desirable that film formation be conducted by sputtering in an atmosphere having a magnetic field intensity of 300 to 1500 gausses. If the magnetic field intensity is 300 gausses or more, since lowering in plasma density can be prevented, sputtering can be conducted without problems even if the sputtering target has a high resistance. On the other hand, if the magnetic field intensity is 1500 gausses or less, deterioration in controllability of the film thickness and the electric characteristics of the film can be suppressed.
  • the pressure of a gas atmosphere is preferably 0.1 to 3.0 Pa, further preferably 0.1 to 1.5 Pa, with 0.1 to 1.0 Pa being particularly preferable. If the sputtering pressure is 3.0 Pa or less, the mean free path of sputtering particles is not shortened excessively, thereby preventing lowering in density of a thin film. If the sputtering pressure is 0.1 Pa or more, fine crystals can be prevented from being formed in a film during film formation.
  • the sputtering pressure is the total pressure in the system at the start of sputtering after rare gas atoms (e.g. argon), water molecules, oxygen molecules or the like are introduced.
  • rare gas atoms e.g. argon
  • water molecules, oxygen molecules or the like are introduced.
  • the formation of an oxide semiconductor thin film may be conducted by the following AC sputtering.
  • Substrates are transported in sequence to positions opposing to three or more targets arranged in parallel with a prescribed interval in a vacuum chamber. Then, a negative potential and a positive potential are applied alternately from an AC power source to each of the targets, whereby plasma is caused to be generated on the target and a film is formed on the surface of the substrate.
  • film formation is conducted by applying at least one output from an AC power source while switching the target to which a potential is applied among two or more targets connected divergently. That is, at least one output from the AC power source is connected divergently to two or more targets respectively, whereby film formation is conducted while applying different potentials to the adjacent targets.
  • an oxide semiconductor thin film is formed by AC sputtering
  • sputtering be conducted in an atmosphere of a mixed gas containing a rare gas, and one or more gases selected from water vapor, an oxygen gas and a nitrous oxide gas, for example. It is particularly preferred that sputtering be conducted in an atmosphere of a mixed gas containing water vapor.
  • the AC sputtering apparatus disclosed in JP-A-2005-290550 specifically has a vacuum chamber, a substrate holder arranged within the vacuum chamber and a sputtering source arranged at a position opposing to this substrate holder.
  • FIG. 1 shows essential parts of a sputtering source of the AC sputtering apparatus.
  • the sputtering source has a plurality of sputtering parts, which respectively have plate-like targets 31 a to 31 f . Assuming that the surface to be sputtered of each target 31 a to 31 f is a sputtering surface, the sputtering parts are arranged such that the sputtering surfaces are on the same plane.
  • Targets 31 a to 31 f are formed in a long and narrow form having a longitudinal direction, and they have the same shape.
  • the targets are arranged such that the edge parts (side surface) in the longitudinal direction of the sputtering surface are arranged in parallel with a prescribed interval therebetween. Accordingly, the side surfaces of the adjacent targets 31 a to 31 f are in parallel.
  • AC power sources 17 a to 17 c are arranged.
  • one terminal is connected to one electrode of the adjacent two electrodes, and the other terminal is connected to the other electrode.
  • the two terminals of each AC power source 17 a to 17 c output voltages differing in polarity (positive and negative), and the targets of 31 a to 31 f are fitted in close contact with the electrode, whereby, to adjacent two targets 31 a to 31 f , an alternate voltage differing in polarity is applied from the AC power sources 17 a to 17 c . Therefore, among the adjacent targets of 31 a to 31 f , if one is set in a positive potential, the other is set in a negative potential.
  • Each magnetic field forming means 40 a to 40 f has a long and narrow ring-like magnet having an approximately same size as that of the outer circumference of the targets 31 a to 31 f , and a bar-like magnet which is shorter than the length of the ring-like magnet.
  • Each ring-like magnet is arranged at the position right behind one corresponding target 31 a to 31 f such that the ring-like magnets are arranged in parallel with the longitudinal direction of the targets 31 a to 31 f .
  • the ring-like magnets are arranged with the same interval as that for the targets 31 a to 31 f from each other.
  • the AC power density when an oxide target is used in AC sputtering is preferably 3 W/cm 2 or more and 20 W/cm 2 or less. If the power density is 3 W/cm 2 or more, the film-forming speed does not become too slow, and ensures economical advantage in respect of production. A power density of 20 W/cm 2 or less can prevent breakage of the target. A more preferable power density is 3 W/cm 2 to 15 W/cm 2 .
  • the frequency of the AC sputtering is preferably in a range of 10 kHz to 1 MHz. If the frequency is 10 kHz or more, noise problems hardly occur. If the frequency is 1 MHz or less, sputtering in other places than the desired target position due to excessively wide scattering of plasma can be prevented from being conducted, whereby uniformity can be kept.
  • a more preferable AC sputtering frequency is 20 kHz to 500 kHz.
  • Conditions or the like at the time of sputtering other than those mentioned above may be appropriately selected from the conditions given above.
  • the above-mentioned oxide semiconductor thin film can be used in a thin film transistor (TFT). It can be used particularly preferably as a channel layer.
  • TFT thin film transistor
  • the TFT of the invention preferably has a field effect mobility of 10 cm 2 Ns or more, more preferably 13 cm 2 Ns or more.
  • the field effect mobility can be measured by the method described in the Examples.
  • the film thickness of the channel layer in the thin film transistor of the invention is normally 10 to 300 nm, preferably 20 to 250 nm, more preferably 30 to 200 nm, further preferably 35 to 120 nm, and particularly preferably 40 to 80 nm. If the film thickness of the channel layer is 10 nm or more, the film thickness does not become non-uniform easily even when the film is formed to have a large area, the properties of a TFT fabricated may become uniform within the plane. If the film thickness is 300 nm or less, the film formation time is not excessively prolonged.
  • the channel layer in the thin film transistor of the invention is normally used in the N-type region.
  • the channel layer in combination with various P-type semiconductors such as a P-type Si-based semiconductor, a P-type oxide semiconductor and a P-type organic semiconductor, the channel layer can be used in various semiconductor devices such as a PN junction transistor.
  • the protective film in the thin film transistor of the invention comprise at least SiN x .
  • SiN x is capable of forming a dense film, and hence has an advantage that it has significant effects of preventing deterioration of a TFT.
  • the protective film may comprise, in addition to SiNx, an oxide such as SiO 2 , Al 2 O 3 , Ta 2 O 5 , TiO 2 , MgO, ZrO 2 , CeO 2 , K 2 O, Li 2 O, Na 2 O, Rb 2 O, Sc 2 O 3 , Y 2 O 3 , HfO 2 , CaHfO 3 , PbTiO 3 , BaTa 2 O 6 , Sm 2 O 3 , SrTiO 3 or AlN.
  • an oxide such as SiO 2 , Al 2 O 3 , Ta 2 O 5 , TiO 2 , MgO, ZrO 2 , CeO 2 , K 2 O, Li 2 O, Na 2 O, Rb 2 O, Sc 2 O 3 , Y 2 O 3 , HfO 2 , CaHfO 3 , PbTiO 3 , BaTa 2 O 6 , Sm 2 O 3 , SrTiO 3 or AlN.
  • the oxide thin film of the invention that comprises an indium (In) element, a tin (Sn) element, a zinc (Zn) element and an aluminum (Al) element, since it contains Al, resistance to reduction by the CVD process is improved. As a result, the back channel side is hardly reduced by a process in which a protective film is prepared, whereby SiN x can be used as a protective film.
  • the channel layer be subjected to an ozone treatment, an oxygen plasma treatment, a nitrogen dioxide plasma treatment or a nitrous oxide plasma treatment.
  • an oxygen plasma treatment a nitrogen dioxide plasma treatment or a nitrous oxide plasma treatment.
  • Such a treatment may be conducted at any time as long as it is after the formation of a channel layer and before the formation of a protective film. However, it is desirable that the treatment be conducted immediately before the formation of a protective film. By conducting such a pre-treatment, generation of oxygen deficiency in the channel layer can be suppressed.
  • the threshold voltage may be shifted, resulting in lowering of reliability of a TFT.
  • an oxygen plasma treatment or a nitrous oxide plasma treatment the In—OH bonding in the thin film structure is stabilized, whereby diffusion of hydrogen in the oxide semiconductor film can be suppressed.
  • the thin film transistor normally comprises a substrate, a gate electrode, a gate insulating layer, an organic semiconductor layer (channel layer), a source electrode and a drain electrode.
  • the channel layer is as mentioned above.
  • a known material can be used for the substrate.
  • a material which is generally used can be arbitrarily selected. Specifically, a compound such as SiO 2 , SiN X , Al 2 O 3 , Ta 2 O 5 , TiO 2 , MgO, ZrO 2 , CeO 2 , K 2 O, Li 2 O, Na 2 O, Rb 2 O, Sc 2 O 3 , Y 2 O 3 , HfO 2 , CaHfO 3 , PbTiO 3 , BaTa 2 O 6 , SrTiO 3 , Sm 2 O 3 , AlN or the like can be used, for example.
  • a compound such as SiO 2 , SiN X , Al 2 O 3 , Ta 2 O 5 , TiO 2 , MgO, ZrO 2 , CeO 2 , K 2 O, Li 2 O, Na 2 O, Rb 2 O, Sc 2 O 3 , Y 2 O 3 , HfO 2 , CaHfO 3 , PbTiO 3 , BaTa
  • SiO 2 , SiN X , Al 2 O 3 , Y 2 O 3 , HfO 2 and CaHfO 3 are preferable, with SiO 2 , SiN X , HfO 2 and Al 2 O 3 being more preferable.
  • the gate insulating film can be formed by the plasma CVD (Chemical Vapor Deposition) method, for example.
  • a gate insulating film is formed by the plasma CVD method and a channel layer is formed thereon, hydrogen in the gate insulating film diffuses in the channel layer, and as a result, deterioration of film quality of the channel layer or lowering of reliability of a TFT may be caused.
  • the gate insulating film be subjected to an ozone treatment, an oxygen plasma treatment, a nitrogen dioxide plasma treatment or a nitrous oxide plasma treatment before the formation of a channel layer.
  • the number of oxygen atoms of these oxides does not necessarily coincide with the stoichiometric ratio.
  • SiO 2 or SiO x may be used.
  • the gate insulting film may have a structure in which two or more insulating films composed of different materials are stacked.
  • the gate insulating film may be crystalline, polycrystalline, or amorphous.
  • the gate insulating film is preferably polycrystalline or amorphous from the viewpoint of easiness of industrial production.
  • each electrode in the thin film transistor i.e. a drain electrode, a source electrode and a gate electrode
  • materials which are generally used can be arbitrarily selected.
  • transparent electrodes such as ITO, IZO, ZnO, SnO 2 or the like
  • a metal electrode such as Al, Ag, Cu, Cr, Ni, Mo, Au, Ti, and Ta or an alloy metal electrode containing these metals can be used.
  • Each of the drain electrode, the source electrode and the gate electrode may have a multi-layer structure in which two or more different conductive layers are stacked.
  • the electrodes since the source/drain electrodes are required to be used in low-resistance wiring, the electrodes may be used by sandwiching a good conductor such as Al and Cu between metals having good adhesiveness such as Ti and Mo.
  • the thin film transistor of the invention can be applied to various integrated circuits such as a field effect transistor, a logical circuit, a memory circuit and a differential amplifier circuit. Further, in addition to a field effect transistor, it can be applied to a static induction transistor, a Schottky barrier transistor, a Schottky diode and a resistance element.
  • a known configuration such as a bottom-gate configuration, a bottom-contact configuration and a top-contact configuration can be used without restrictions.
  • a bottom-gate configuration is advantageous since high performance can be obtained as compared with a thin film transistor comprising amorphous silicon or ZnO.
  • the bottom-gate configuration is preferable since the number of masks at the time of production can be decreased easily and the production cost for application such as a large-sized display or the like can be reduced easily.
  • the thin film transistor of the invention can preferably be used as a display.
  • a channel-etch type bottom-gate thin film transistor For use in a large-sized display, a channel-etch type bottom-gate thin film transistor is particularly preferable.
  • a channel-etch type bottom-gate thin film transistor can produce a panel for a display at a low cost since the number of photo-masks used in photolithography is small.
  • a channel-etch type thin film transistor having a bottom-gate configuration and a channel-etch type thin film transistor having a top-contact configuration are particularly preferable since they have excellent properties such as mobility and can be industrialized easily.
  • the median size D50 was employed as an average particle size for the following oxide powders.
  • the average particle size was measured by a laser diffraction particle size analyzer SALD-300V (manufactured by Shimadzu Corporation).
  • Indium oxide powder average particle size 0.98 ⁇ m
  • Tin oxide powder average particle size 0.98 ⁇ m
  • Zinc oxide powder average particle size 0.96 ⁇ m
  • Aluminum oxide powder average particle size 0.98 ⁇ m
  • the above-mentioned powders were weighed such that the atomic ratio shown in Table 1 was attained. They were finely pulverized and mixed uniformly and then granulated by adding a binder for forming. Subsequently, the mixed powder of the raw materials was filled in the mold uniformly and press-formed at a pressing pressure of 140 MPa in a cold press apparatus.
  • the formed body obtained was sintered in a sintering furnace at a temperature-elevating rate (from 800° C. to the sintering temperature), a sintering temperature, a sintering time and a temperature-decreasing rate shown in Table 1 to produce a sintered body.
  • a temperature-elevating rate from 800° C. to the sintering temperature
  • a sintering temperature from 800° C. to the sintering temperature
  • a sintering time a temperature-decreasing rate shown in Table 1
  • the relative density of the sintered body obtained was measured by the Archimedean method.
  • the sintered bodies of Examples 1 to 6 were confirmed to have a relative density of 98% or more.
  • the bulk specific resistance (conductivity) of the sintered body obtained was measured by means of a resistivity meter (Loresta, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) in accordance with the four point probe method (JIS R 1637). The results are shown in Table 1. As shown in Table 1, the bulk specific resistances of the sintered bodies of Examples 1 to 6 were 10 m ⁇ cm or less.
  • each of the sintered body obtained was determined by means of an X-ray diffraction (XRD) apparatus.
  • X-ray diffraction charts of the sintered bodies obtained in Examples 1 to 6 are shown in FIGS. 2 to 7 , respectively.
  • the formed compounds contained in the sintered body are shown in Table 2.
  • the homologous structure represented by InAlZnO 4 has a peak pattern of No. 40-0258 of the JCPDS database.
  • the bixbyite structure represented by In 2 O 3 has a peak pattern of No. 06-0416 of the JCPDS data base.
  • Example 2 In the sintered body of Example 2, the homologous structure represented by InAlZn 2 O 5 and the bixbyite structure represented by In 2 O 3 were observed.
  • the homologous structure represented by InAlZn 2 O 5 has a peak pattern of No. 40-0259 of the JCPDS data base.
  • Example 3 In the sintered body of Example 3, the homologous structure represented by InAlZn 2 O 5 , the homologous structure represented by InAlZnO 4 and the bixbyite structure represented by In 2 O 3 were observed.
  • Example 5 In the sintered body of Example 5, the homologous structure represented by InAlZn 2 O 5 , the homologous structure represented by InAlZnO 4 and the bixbyite structure represented by In 2 O 3 were observed.
  • the spinel structure represented by Zn 2 SnO 4 was not observed in the sintered bodies of Examples 1 to 6.
  • the X-ray diffraction measurement (XRD) was measured under the following conditions.
  • the dispersion of Sn or Al in the sintered body obtained by the electron probe microanalyzer (EPMA) measurement was checked. An 8 ⁇ m or larger-sized aggregation of Sn or Al was not observed. As a result, the sputtering targets of the invention were found to be significantly excellent in dispersivity and homogeneousness.
  • the EPMA measurement was conducted under the following conditions.
  • the surface of the sintered bodies obtained in Examples 1 to 6 was ground by means of a surface grinder. The sides thereof were cut using a diamond cutter. The sintered bodies were bonded to a backing plate, thereby to obtain sputtering targets each having a diameter of 4 inches. Further, in Examples 1, 3 and 4, targets each having a width of 200 mm, a length of 1700 mm and a thickness of 10 mm were fabricated for AC sputtering film-forming (Examples 13 to 15, mentioned later).
  • a sputtering target having a diameter of 4 inches obtained was mounted in a DC sputtering apparatus.
  • a mixed gas obtained by adding a H 2 O gas to an argon gas at a partial pressure ratio of 2% was used as the atmosphere.
  • a 10 kWh continuous sputtering was conducted at a DC power of 400 W with the sputtering pressure being 0.4 Pa and the substrate temperature being room temperature. Variations in voltage during the sputtering were stored in data logger to confirm the presence or absence of abnormal discharge. The results are shown in Table 2.
  • abnormal discharge is defined by the case where the voltage variation generated for a measurement time of 5 minutes is 10% or more of the working voltage during sputtering operation.
  • micro arcs which are abnormal discharge of sputtering discharge, may generate, thereby lowering the yield of a device. Accordingly, they may be unsuitable for mass production.
  • Sputtering was conducted continuously for 40 hours by using a 4-inch-diameter sputtering target obtained with the atmosphere being a mixed gas obtained by adding a hydrogen gas to an argon gas at a partial pressure ratio of 3% to confirm the presence or absence of nodule generation.
  • the atmosphere being a mixed gas obtained by adding a hydrogen gas to an argon gas at a partial pressure ratio of 3% to confirm the presence or absence of nodule generation.
  • the conditions at the time of the sputtering include a sputtering pressure of 0.4 Pa, a DC power of 100 W and a substrate temperature of room temperature.
  • the hydrogen gas was added to the atmosphere gas in order to promote nodule generation.
  • nodules For evaluation of nodules, the following method was employed. The change in the target surface after sputtering was observed at a magnification of 50 times by means of a stereomicroscope. The number average of nodules having a size of 20 ⁇ m or larger generated in the visual field of 3 mm 2 was calculated. Table 2 shows the number of nodules generated.
  • Sintered bodies and sputtering targets were produced and evaluated in the same manner as in Example 1, except that the raw material powders were mixed according to the atomic ratio shown in Table 1, and sintered at a temperature-elevating rate (from 800° C. to the sintering temperature), at a sintering temperature, for a sintering time shown in Table 1 and at a temperature-decreasing rate of 15° C./min. The results are shown in Tables 1 and 2.
  • the homologous structure compound represented by InAlO 3 (ZnO) m (m is 0.1 to 10) was not observed, and the bixbyite structure represented by In 2 O 3 and the spinel structure represented by Zn 2 SnO 4 were observed.
  • the spinel structure represented by Zn 2 SnO 4 has a peak pattern of No. 24-1470 of the JCPDS card.
  • the 4-inch targets produced in Examples 1 to 6 and having the compositions shown in Table 3 or 4 were mounted in a magnetron sputtering apparatus, and slide glass (#1737, manufactured by Corning Inc.) was installed as a substrate in each case.
  • slide glass #1737, manufactured by Corning Inc.
  • a 50 nm-thick amorphous film was formed on the slide glass under the following conditions.
  • an Ar gas, an O 2 gas and a H 2 O gas were introduced at partial pressure ratios (%) shown in Table 3 or 4.
  • the substrate on which an amorphous film had been formed was heated in an atmosphere at 300° C. for 60 minutes.
  • Substrate temperature 80° C.
  • Atmospheric gas Ar gas, O 2 gas, H 2 O gas (for partial pressure, see Tables 3 and 4)
  • a glass substrate on which an oxide semiconductor film had been formed was set in a Resi Test 8300 (manufactured by TOYO Corporation), and the Hall effect was evaluated at room temperature. Specifically, a carrier concentration was determined. The results are shown in Tables 3 and 4.
  • the crystal structure of the oxide thin film formed on the glass substrate was examined by means of an X-ray diffraction measurement apparatus (Ultima-III, manufactured by Rigaku Corporation). In Examples 7 to 12, no diffraction peaks were observed immediately after the deposition of the thin film, and hence it was confirmed that the thin film was amorphous. After conducting a heat treatment (annealing) in the air at 300° C. for 60 minutes, no diffraction peaks were observed, and the thin film was confirmed to be amorphous.
  • the measuring conditions of the XRD are as follows.
  • a conductive silicon substrate provided with a 100 nm-thick thermally oxidized film was used.
  • the thermally oxidized film functioned as a gate insulating film and the conductive silicon part functioned as a gate electrode.
  • a film was formed by sputtering under the conditions shown in Tables 3 and 4, whereby a 50 nm-thick amorphous thin film was formed.
  • a resist OFPR#800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used. Coating, pre-baking (80° C., 5 minutes) and exposure were conducted. After development, post-baking (120° C., 5 minutes), etching with oxalic acid, and patterning into a desired shape were conducted. Thereafter, the film was subjected to a heat treatment at 300° C. for 60 minutes in a hot-air oven (annealing treatment).
  • Mo 100 nm
  • source/drain electrodes were patterned by the lift-off method in a desired shape.
  • Tables 3 and 4 as a pre-treatment before forming a protective film, an oxide semiconductor film was subjected to a nitrous oxide plasma treatment. Further, SiO x was formed into a film having a thickness of 100 nm by the plasma CVD (PECVD) method and SiN x was formed on the SiO x film in a thickness of 150 nm by the plasma CVD (PECVD) method to obtain a protective film. A contact hole was formed by dry etching, whereby a thin film transistor was fabricated.
  • PECVD plasma CVD
  • a field effect mobility (p), an S value and a threshold voltage (Vth) were evaluated. These characteristic values were measured by using a semiconductor parameter analyzer (4200SCS, manufactured by Keithley Instruments, Inc.) at room temperature in a light-shielding environment (in a shield box).
  • oxide semiconductor thin films and thin film transistors were fabricated and evaluated in the same manner as in Examples 7 to 12 in accordance with the sputtering conditions, heating (annealing) conditions and a pre-treatment for forming a protective film shown in Table 4. The results are shown in Table 4.
  • the AC sputtering was specifically conducted as follows by using the apparatus shown in FIG. 1 .
  • targets 31 a to 31 f (each having a width of 200 mm, a length of 1700 mm and a thickness of 10 mm) fabricated in Example 1, 3 or 4 were used. These targets 31 a to 31 f were arranged in parallel to the direction of the width of a substrate such that they remote from each other with an interval of 2 mm.
  • the width of the magnetic field forming means 40 a to 40 f was 200 mm as in the case of targets 31 a to 31 f . From the gas supply system, Ar, H 2 O and/or O 2 as the sputtering gas were respectively introduced into the system.
  • film formation was conducted for 10 seconds.
  • the film thickness of the resulting thin film was measured and found to be 13 nm.
  • the film formation speed was as high as 78 nm/min, which is suited to mass production.
  • the glass substrate on which a thin film had been formed was put in an electric furnace, and subjected to a heat treatment in the air at 300° C. for 60 minutes (in the air atmosphere).
  • the thin film was cut into a size of 1 cm 2 , and then subjected to the Hall measurement by the four point probe method.
  • the carrier concentration was 4.83 ⁇ 10 17 cm ⁇ 3 , indicating that the film became a sufficient semiconductor.
  • the oxide thin film was amorphous immediately after the thin film deposition, and was still amorphous after allowing it to stand in the air at 300° C. for 60 minutes.
  • the thin film transistor obtained by using the sputtering target of the invention can be used for a display, in particular, for a large-area display.
US14/442,686 2012-11-14 2013-11-08 Sputtering target, oxide semiconductor thin film, and method for producing these Abandoned US20160293412A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2012250303A JP6059513B2 (ja) 2012-11-14 2012-11-14 スパッタリングターゲット、酸化物半導体薄膜及びそれらの製造方法
JP2012-250303 2012-11-14
PCT/JP2013/006597 WO2014076916A1 (ja) 2012-11-14 2013-11-08 スパッタリングターゲット、酸化物半導体薄膜及びそれらの製造方法

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2013/006597 A-371-Of-International WO2014076916A1 (ja) 2012-11-14 2013-11-08 スパッタリングターゲット、酸化物半導体薄膜及びそれらの製造方法

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US16/211,211 Continuation US11443943B2 (en) 2012-11-14 2018-12-05 Sputtering target, oxide semiconductor thin film, and method for producing these

Publications (1)

Publication Number Publication Date
US20160293412A1 true US20160293412A1 (en) 2016-10-06

Family

ID=50730851

Family Applications (2)

Application Number Title Priority Date Filing Date
US14/442,686 Abandoned US20160293412A1 (en) 2012-11-14 2013-11-08 Sputtering target, oxide semiconductor thin film, and method for producing these
US16/211,211 Active 2034-12-26 US11443943B2 (en) 2012-11-14 2018-12-05 Sputtering target, oxide semiconductor thin film, and method for producing these

Family Applications After (1)

Application Number Title Priority Date Filing Date
US16/211,211 Active 2034-12-26 US11443943B2 (en) 2012-11-14 2018-12-05 Sputtering target, oxide semiconductor thin film, and method for producing these

Country Status (6)

Country Link
US (2) US20160293412A1 (ja)
JP (1) JP6059513B2 (ja)
KR (2) KR20200108493A (ja)
CN (2) CN104704138B (ja)
TW (1) TWI619825B (ja)
WO (1) WO2014076916A1 (ja)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20010046034A (ko) * 1999-11-10 2001-06-05 배준집 재사용가능한 체결고정구
JP6266853B1 (ja) * 2016-04-26 2018-01-24 出光興産株式会社 酸化物焼結体、スパッタリングターゲット及び酸化物半導体膜
CN107492490B (zh) * 2016-06-12 2020-03-31 北京北方华创微电子装备有限公司 半导体设备的成膜方法、氮化铝成膜方法以及电子装置
CN106521415B (zh) * 2016-10-27 2020-05-19 中山大学 一种改良的氧化铟透明导电薄膜退火方法
US20210070961A1 (en) * 2018-02-08 2021-03-11 Sumitomo Metal Mining Co., Ltd. Near-infrared absorbing material fine particle dispersion body, near-infrared absorbing body, near-infrared absorbing substance laminated body and combined structure for near infrared absorption

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100155717A1 (en) * 2007-03-26 2010-06-24 Idemitsu Kosan Co., Ltd. Noncrystalline oxide semiconductor thin film, process for producing the noncrystalline oxide semiconductor thin film, process for producing thin-film transistor, field-effect-transistor, light emitting device, display device, and sputtering target
US20110168994A1 (en) * 2008-06-06 2011-07-14 Hirokazu Kawashima Sputtering target for oxide thin film and process for producing the sputtering target

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3947575B2 (ja) 1994-06-10 2007-07-25 Ｈｏｙａ株式会社 導電性酸化物およびそれを用いた電極
JPH07333438A (ja) * 1994-06-14 1995-12-22 Idemitsu Kosan Co Ltd 導電性偏光板およびその製造方法
JP3746094B2 (ja) * 1995-06-28 2006-02-15 出光興産株式会社 ターゲットおよびその製造方法
US6679977B2 (en) * 1997-12-17 2004-01-20 Unakis Trading Ag Method of producing flat panels
CN101650955B (zh) 2003-03-04 2011-08-24 Jx日矿日石金属株式会社 溅射靶、光信息记录介质用薄膜及其制造方法
JP4417913B2 (ja) 2004-02-17 2010-02-17 日鉱金属株式会社 スパッタリングターゲット並びに光情報記録媒体及びその製造方法
WO2005078153A1 (ja) 2004-02-17 2005-08-25 Nippon Mining & Metals Co., Ltd. スパッタリングターゲット並びに光情報記録媒体及びその製造方法
KR101078509B1 (ko) 2004-03-12 2011-10-31 도꾸리쯔교세이호징 가가꾸 기쥬쯔 신꼬 기꼬 박막 트랜지스터의 제조 방법
JP4981282B2 (ja) * 2005-09-06 2012-07-18 キヤノン株式会社 薄膜トランジスタの製造方法
JP5058469B2 (ja) 2005-09-06 2012-10-24 キヤノン株式会社 スパッタリングターゲットおよび該ターゲットを用いた薄膜の形成方法
WO2009081885A1 (ja) 2007-12-25 2009-07-02 Idemitsu Kosan Co., Ltd. 酸化物半導体電界効果型トランジスタ及びその製造方法
US8148245B2 (en) 2007-12-27 2012-04-03 Jx Nippon Mining & Metals Corporation Method for producing a-IGZO oxide thin film
WO2011132418A1 (ja) * 2010-04-22 2011-10-27 出光興産株式会社 成膜方法
EP2428994A1 (en) * 2010-09-10 2012-03-14 Applied Materials, Inc. Method and system for depositing a thin-film transistor
US9214519B2 (en) * 2011-05-10 2015-12-15 Idemitsu Kosan Co., Ltd. In2O3—SnO2—ZnO sputtering target

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100155717A1 (en) * 2007-03-26 2010-06-24 Idemitsu Kosan Co., Ltd. Noncrystalline oxide semiconductor thin film, process for producing the noncrystalline oxide semiconductor thin film, process for producing thin-film transistor, field-effect-transistor, light emitting device, display device, and sputtering target
US20110168994A1 (en) * 2008-06-06 2011-07-14 Hirokazu Kawashima Sputtering target for oxide thin film and process for producing the sputtering target

Also Published As

Publication number Publication date
CN108546090B (zh) 2021-11-09
JP6059513B2 (ja) 2017-01-11
CN104704138A (zh) 2015-06-10
KR20200108493A (ko) 2020-09-18
JP2014099493A (ja) 2014-05-29
US11443943B2 (en) 2022-09-13
TW201428120A (zh) 2014-07-16
CN108546090A (zh) 2018-09-18
TWI619825B (zh) 2018-04-01
WO2014076916A1 (ja) 2014-05-22
US20190109001A1 (en) 2019-04-11
CN104704138B (zh) 2018-07-13
KR20150084846A (ko) 2015-07-22

Similar Documents

Publication Publication Date Title
US11462399B2 (en) Sputtering target, oxide semiconductor thin film, and method for producing oxide semiconductor thin film
US9767998B2 (en) Sputtering target
US11443943B2 (en) Sputtering target, oxide semiconductor thin film, and method for producing these
WO2014073210A1 (ja) スパッタリングターゲット、酸化物半導体薄膜及びそれらの製造方法
US20150332902A1 (en) Sputtering target, oxide semiconductor thin film, and methods for producing these
US9039944B2 (en) Sputtering target
TWI632123B (zh) 濺鍍靶、氧化物半導體薄膜及具備該氧化物半導體薄膜之薄膜電晶體
JP2014214359A (ja) スパッタリングターゲット、酸化物半導体薄膜及び当該酸化物半導体薄膜を備える薄膜トランジスタ
WO2014112369A1 (ja) スパッタリングターゲット、酸化物半導体薄膜及びこれらの製造方法
WO2014112368A1 (ja) スパッタリングターゲット、酸化物半導体薄膜及びそれらの製造方法
JP6141332B2 (ja) スパッタリングターゲット、酸化物半導体薄膜及びそれらの製造方法
JP6188712B2 (ja) スパッタリングターゲット
JP6470352B2 (ja) 酸化物半導体薄膜
WO2014038204A1 (ja) スパッタリングターゲット
WO2014034122A1 (ja) スパッタリングターゲット

Legal Events

Date Code Title Description
AS Assignment

Owner name: IDEMITSU KOSAN CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:EBATA, KAZUAKI;TAJIMA, NOZOMI;SIGNING DATES FROM 20150226 TO 20150227;REEL/FRAME:035632/0843

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION