WO2013042747A1 - Oxide sintered body, method for producing same, and oxide transparent conductive film - Google Patents

Oxide sintered body, method for producing same, and oxide transparent conductive film Download PDF

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Publication number
WO2013042747A1
WO2013042747A1 PCT/JP2012/074111 JP2012074111W WO2013042747A1 WO 2013042747 A1 WO2013042747 A1 WO 2013042747A1 JP 2012074111 W JP2012074111 W JP 2012074111W WO 2013042747 A1 WO2013042747 A1 WO 2013042747A1
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oxide
transparent conductive
conductive film
sintered body
film
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PCT/JP2012/074111
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French (fr)
Japanese (ja)
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桑原　正和
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住友金属鉱山株式会社
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Publication of WO2013042747A1 publication Critical patent/WO2013042747A1/en

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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
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Definitions

  • the present invention relates to an oxide transparent conductive film used for a display element such as a touch panel, electronic paper, a solar cell, and an optical device such as a light emitting diode (LED) or an organic electroluminescence (EL), and the oxide transparent conductive film.
  • the present invention relates to an oxide sintered body for obtaining a film and a method for producing the same.
  • the oxide transparent conductive film has high conductivity and high transmittance particularly in the visible light region, display elements such as touch panels and electronic paper, solar cells, and transparent electrodes in optical devices such as LEDs and organic EL, etc. It is widely used as a material. In addition, it is also used for heat ray reflective films, antistatic films, and antifogging transparent heating elements for automobile windows.
  • indium oxide (In 2 O 3 + ⁇ ) oxide film As the oxide transparent conductive film, indium oxide (In 2 O 3 + ⁇ ) oxide film, zinc oxide (ZnO + ⁇ ) oxide film, and tin oxide (SnO 2 + ⁇ ) oxide film are widely used.
  • indium oxide-based oxide films are most often used.
  • indium oxide films containing tin oxide as a dopant are called ITO (Indium Tin Oxide) films, and particularly low resistance films. It is mainly used because it can be easily obtained.
  • a sputtering method is used as a main means for manufacturing these transparent oxide conductive films.
  • Sputtering is an effective technique when film formation of low vapor pressure materials and precise film thickness control are required, and its operation is very simple, so it is widely used industrially. ing.
  • a substrate on which a transparent conductive film is formed is used as an anode
  • a sputtering target is used as a cathode
  • glow discharge is generated between them
  • argon plasma is generated.
  • a film is formed by causing argon cations in the plasma to collide with the sputtering target of the cathode and depositing particles of the target component which are blown off by this on the substrate.
  • Sputtering methods are classified into a direct current sputtering method using direct current discharge and a high frequency sputtering method using high frequency discharge.
  • the high-frequency sputtering method has an advantage that stable deposition can be performed not only on a conductive target but also on a high-resistance target or a target in which a conductive material and a high-resistance material are mixed, but the deposition rate is low and the apparatus cost is low. Has disadvantages such as high price.
  • the direct current sputtering method is generally used industrially because it is inexpensive and has a simple film formation operation and is excellent in high-speed film formation. It is necessary to use sex targets.
  • the high-resistance substance is charged by irradiation with argon ions, and arcing occurs during film formation.
  • a conductive target that does not include is required.
  • the DC magnetron sputtering method has an advantage that the deposition rate is high by placing a magnet on the back side of the target and confining ⁇ electrons in the vicinity of the target by applying a magnetic field.
  • an oxide transparent conductive film such as ITO is formed by DC magnetron sputtering, a sufficiently low resistance film cannot be obtained unless the temperature of the substrate is raised. This is because the higher the substrate temperature at the time of film formation, the better the crystallinity of the film and the doping of the additive components, and the lower the resistance value of the resulting film.
  • Japanese Patent Laid-Open No. 2005-290458 discloses a technique relating to a cerium-containing indium oxide-based sputtering target material (In—Ce—O) and a transparent conductive film obtained using this sputtering target. It is disclosed. This transparent conductive film is assumed to be used in an amorphous state. However, when the substrate temperature is set to 200 ° C. or higher, or the substrate is heated at a temperature of 200 ° C. to 250 ° C., the film may be crystallized. It is shown.
  • JP 2004-43851 A discloses that an oxide transparent conductive film having high conductivity and high transmittance in the visible light region is formed by heating the substrate at a temperature of 200 ° C. or higher to form a crystallinity.
  • An indium oxide film (In—W—O) containing tungsten is disclosed.
  • JP-A-9-209134 and JP-A-9-161542 a transparent conductive film having a higher resistance than that of ITO is obtained by a direct current sputtering method. Therefore, a low-resistance metal element such as titanium, iridium, and cobalt is added to ITO.
  • a resistive sputtering target is disclosed. When these sputtering targets are used, a transparent conductive film is obtained even when the substrate temperature is set to room temperature by direct current magnetron sputtering.
  • the present invention provides an oxide transparent conductive film having sufficient crystallinity, which has high conductivity and high transmittance in the visible light region, and such characteristics. It is an object of the present invention to provide an oxide sintered body capable of depositing an oxide transparent conductive film comprising a film by a direct current sputtering method using a transparent resin substrate.
  • the oxide sintered body of the present invention is an oxide sintered body containing indium oxide as a main component and containing tin oxide and cobalt oxide, and an atomic ratio of Sn to In: Sn / In is 0.019 to 0 .102, and the atomic ratio of each component to the sum of In, Sn, and Co: In / (In + Sn + Co) is 0.771 to 0.967, Sn / (In + Sn + Co) is 0.016 to 0.091, Co / (In + Sn + Co) is 0.015 to 0.15, and its relative density is 98% or more. Furthermore, in the oxide sintered body of the present invention, the specific resistance is preferably 5 ⁇ 10 ⁇ 3 ⁇ ⁇ cm or less.
  • an oxide transparent conductive film having the following characteristics can be obtained even by film formation at a low substrate temperature of 150 ° C. or lower.
  • Such an oxide sintered body uses indium oxide powder, tin oxide powder, and cobalt oxide powder having an average particle size of 0.05 ⁇ m or more and less than 1.0 ⁇ m as raw material powder. , Water and a water-soluble binder were blended, and the resulting slurry was pulverized, stirred for 10 hours or more, dried and granulated, and the resulting granulated powder was packed into a mold and pressure-molded to obtain The molded body can be obtained by sintering at 1450 ° C. to 1600 ° C. for 12 hours to 25 hours in an oxygen atmosphere.
  • the oxide transparent conductive film of the present invention is a transparent conductive film containing indium oxide as a main component and containing tin oxide and cobalt oxide, and the atomic ratio of Sn to In: Sn / In is 0.019 to 0 .102, and the atomic ratio of each component to the sum of In, Sn, and Co: In / (In + Sn + Co) is 0.771 to 0.967, Sn / (In + Sn + Co) is 0.016 to 0.091, Co / (In + Sn + Co) is 0.015 to 0.15, and the specific resistance is 5 ⁇ 10 ⁇ 3 ⁇ ⁇ cm or less.
  • the oxide transparent conductive film of the present invention when the film thickness is 15 nm to 40 nm, it is preferable that the average transmittance of a single film at a wavelength of 400 nm to 800 nm is 98% or more. Moreover, even if it is a case where it exposes to the environment of temperature 95 degreeC and humidity 95% for 1000 hours, it is preferable that the resistance change rate will be 1.2 or less.
  • the specific resistance is 5 ⁇ 10 ⁇ 3 ⁇ ⁇ cm or less.
  • a highly crystalline transparent oxide conductive film having a low resistance and a high transmittance such that the average transmittance of a single film at a visible wavelength of 400 nm to 800 nm is 98% or more can be obtained. That is, even when a transparent resin substrate is used as a substrate during film formation, a crystalline oxide transparent conductive film having low resistance and high transmittance can be formed.
  • the oxide sintered body of the present invention has a high relative density and low resistance, even when used as a sputtering target in the formation of an oxide transparent conductive film by a direct current sputtering method, arcing during film formation is performed. , And the generation of nodules and particles due to this can be prevented.
  • oxide sintered body (2) manufacturing method of oxide sintered body, (3) film formation of transparent conductive film, and (4) transparent conductive film.
  • Oxide sintered body As a result of intensive studies on indium oxide-based oxide sintered bodies, the inventors have added a cobalt oxide in addition to indium oxide and tin oxide, and these The composition ratio of each metal component of indium (In), tin (Sn), and cobalt (Co) constituting the oxide is regulated within a predetermined range, and an oxide sintered body is manufactured under predetermined manufacturing conditions. By doing so, it becomes possible to increase the density of the obtained oxide sintered body and to make the sintered body texture dense, and b) to use the oxide sintered body of the present invention as a sputtering target.
  • the present invention has obtained the knowledge that it has low resistance and high transmittance and has excellent stability with little resistance change even in a high temperature and high humidity environment (temperature 95 ° C., humidity 95%, 1000 h). Has been completed.
  • the content of tin oxide is regulated so as to be within a range of 0.019 to 0.102 in terms of Sn / In atomic ratio of Sn. If the tin oxide content is less than 0.019 Sn / In, the relative density of the sintered body will not be 98% or more, and the specific resistance of the sintered body will be 5 ⁇ 10 ⁇ 3 ⁇ ⁇ cm or less. It will not become. Further, in the transparent conductive film formed using such a sintered body having a small content of tin oxide, the average transmittance of the film does not become 98% or more, and the specific resistance of the film is also 5 ⁇ 10 ⁇ 3.
  • the resistance change rate in a high temperature and high humidity environment exceeds 1.2.
  • the content of tin oxide exceeds 0.102 in Sn / In, the oxide transparent conductive film after film formation does not crystallize at a substrate temperature of 150 ° C. or lower, and the average transmission of the obtained film The rate will not be over 98%.
  • the tin oxide content is preferably in the range of 0.040 to 0.102 in terms of Sn / In.
  • the content of indium oxide, tin oxide, and cobalt oxide is 0.771 to the atomic ratio of each metal component to the total of In, Sn, and Co: In / (In + Sn + Co)
  • the regulation is 0.967, Sn / (In + Sn + Co) is 0.016 to 0.091, and Co / (In + Sn + Co) is 0.015 to 0.15.
  • the density of the oxide sintered body is increased, the sintered body structure is densified, the crystallinity is improved, and the crystal orientation is in a certain direction. Can be controlled. Due to the action of this cobalt oxide, it is possible to stably obtain the characteristics of low resistance and high transmittance in the oxide transparent conductive film by regulating the content of tin oxide, and in particular, resistance in a high temperature and high humidity environment. Excellent stability with a change rate of 1.2 or less is brought about.
  • the cobalt oxide content needs to be 0.015 to 0.15 in terms of the atomic ratio of Co to the total of In, Sn and Co: Co / (In + Sn + Co).
  • the content of cobalt oxide is Co / (In + Sn + Co) and less than 0.015, the density of the oxide sintered body is not sufficiently high, and the specific resistance of the sintered body is also high. In this case, although the obtained transparent conductive film has crystallinity, the specific resistance tends to be high, and the stability is not sufficient.
  • the cobalt oxide content is preferably in the range of 0.05 to 0.15 in terms of Co / (In + Sn + Co).
  • the content of indium oxide is 0.771 to 0.967 in In / (In + Sn + Co), and the content of tin oxide is 0.016 to 0.091 in Sn / (In + Sn + Co). Is preferred.
  • the oxide sintered body of the present invention has a relative density from the viewpoint of effectively preventing the arcing generated during sputtering and the causes affecting the film properties such as the generation of nodules and particles resulting therefrom. Needs to be 98% or more, more preferably 99% or more.
  • the specific ratio (volume resistivity) of the oxide sintered body is set to 5 ⁇ 10 5 by regulating the composition ratio of the oxide sintered body as described above and setting the relative density to 98% or more. ⁇ 3 ⁇ ⁇ cm or less, preferably 1.0 ⁇ 10 ⁇ 3 ⁇ ⁇ cm or less. That is, when an oxide sintered body having a lower relative density and a higher specific resistance than the range defined in the present invention is used, the rate of change in resistance under a high temperature environment deteriorates, and the stability of the film deteriorates. The transmittance of the film is lowered and the specific resistance of the film is also increased.
  • (2-1) Raw material powder As a raw material of the oxide sintered body according to the present invention, indium oxide powder, tin oxide powder and cobalt oxide powder can be used. It is necessary to be 0.05 ⁇ m or more and less than 1.0 ⁇ m. Preferably, the average particle size of these powders is in the range of 0.1 ⁇ m or more and less than 0.8 ⁇ m.
  • the average particle size is less than 0.05 ⁇ m, the powder aggregates and it becomes difficult to mix uniformly.
  • the thickness is 1.0 ⁇ m or more, the resulting oxide sintered body cannot have a relative density of 98% or more. For this reason, arcing generated during sputtering occurs, and the characteristics of the film deteriorate due to generation of nodules and particles resulting from the arcing.
  • the mixing ratio of these powders may be determined according to the composition ratio of the target oxide sintered body, that is, the atomic ratio of each metal component. Specifically, the atomic ratio of Sn to In: Sn / In is set to 0.019 to 0.102, and the atomic ratio of each component to the total of In, Sn, and Co: In / (In + Sn + Co) is Preparation may be made so that 0.771 to 0.967, Sn / (In + Sn + Co) is 0.016 to 0.091, and Co / (In + Sn + Co) is 0.015 to 0.15.
  • a water-soluble binder is added to these raw material powders in an amount of 0.5 to 1.5% by mass, and is further placed in a resin pot together with water. Grind and mix.
  • the water-soluble binder is not limited as long as it is a known binder that disappears or vaporizes by heating, and for example, polyvinyl alcohol (PVA), polyvinyl butyral, methyl cellulose, and the like can be used.
  • a ball mill and a bead mill can be used for this process.
  • a ball mill in terms of cost
  • a bead mill from the viewpoint of work efficiency because the ball mill takes much time to grind.
  • the balls and beads for example, those made of hard zirconia (ZrO 2 ) are preferably used.
  • the grindability changes depending on the ball diameter or bead diameter, it is preferable to use a ball having a diameter of about ⁇ 2 mm to ⁇ 6 mm and a bead of about ⁇ 0.2 mm to ⁇ 0.7 mm.
  • the wet pulverization and mixing conditions are preferably 50 to 70 rpm and a pulverization / mixing time of 15 to 28 hours.
  • the number of rotations is preferably 1300 rpm to 1700 rpm, and the pulverization / mixing time is preferably 3 hours to 6 hours.
  • the time for pulverization and mixing is insufficient, the sintered body density finally obtained decreases.
  • zirconia is mixed as an impurity, and the density of the sintered body similarly decreases.
  • a slurry containing raw material powder having an average particle size of 0.5 ⁇ m or less is obtained.
  • the average particle diameter is preferably in the range of 0.1 ⁇ m to 0.5 ⁇ m.
  • the viscosity of the slurry is preferably 30 mPa ⁇ s to 600 mPa ⁇ s.
  • the slurry containing the raw material powder obtained in the above step is spray dried to obtain granulated powder.
  • a spherical granulated powder by using a spray dryer.
  • the drying temperature during spray drying is preferably in the range of 120 ° C to 200 ° C. Further, it is preferable to appropriately adjust the drying speed according to the amount of exhaust air so that spherical granulated powder can be obtained according to the apparatus.
  • a spray dryer it is preferable to use a spray dryer using a disk having excellent mass productivity.
  • the particle size of the granulated powder is desirably 40 ⁇ m to 100 ⁇ m in terms of average particle size.
  • the granulated powder obtained through the spray drying step is filled in a rubber mold and is subjected to a pressure of 250 MPa to 350 MPa, more preferably 280 MPa to 320 MPa, using a cold isostatic press (CIP). Molding is performed at a pressure of. At this time, CIP may be performed after preforming by uniaxial pressing.
  • CIP cold isostatic press
  • the maximum pressure holding time during molding is preferably 1 to 10 minutes.
  • the gas generated by decomposing the water-soluble binder is discharged out of the furnace together with oxygen, thus promoting binder removal.
  • a high-strength and high-density sintered body can be obtained.
  • the oxygen concentration can be up to 100% by volume (pure oxygen atmosphere), but about 30% by volume is sufficient from the viewpoint of cost.
  • the heating temperature during binder removal is preferably 200 ° C. to 800 ° C., and the heating time is preferably 30 hours or more.
  • the heating temperature is less than 200 ° C.
  • the binder remains without volatilization, leading to a decrease in the density of the sintered body.
  • the temperature exceeds 800 ° C.
  • shrinkage of the molded body starts during the binder removal step, so that the binder remains inside the sintered body, causing a problem of density reduction.
  • the heating time is less than 30 hours, the binder may not be sufficiently decomposed.
  • the rate of temperature rise is preferably 0.1 ° C./min to 1.5 ° C./min, and 0.3 ° C./min to 1.0 ° C./min. More preferably, minutes.
  • the compact is sintered by firing at a temperature of 1450 ° C. to 1600 ° C. for 10 hours to 25 hours under atmospheric pressure.
  • the firing temperature is preferably 1450 ° C. to 1600 ° C., more preferably 1470 ° C. to 1570 ° C.
  • the liquid phase sintering can proceed sufficiently to increase the density of the sintered body, and further, the indium oxide can be prevented from melting and sintered in a desired shape.
  • the body can be easily manufactured.
  • the holding time at the above baking temperature is preferably 10 hours to 25 hours, and more preferably 15 hours to 20 hours. Within this range, a high-quality indium oxide-based oxide sintered body can be obtained while realizing a reduction in sintering time (reduction in power consumption) and high productivity.
  • the rate of temperature rise is preferably 0.1 ° C./min to 1.5 ° C./min, preferably 0.3 ° C./min. More preferably, it is set to ⁇ 1.0 ° C./min. Further, after holding at the firing temperature for a predetermined time, it is preferable to cool to near room temperature at a cooling rate in the range of 0.2 ° C./min to 1.2 ° C./min.
  • the sputtering method for film formation using the oxide sintered body of the present invention as a sputtering target is not limited at all, and any known means can be used. However, from the viewpoint of mass productivity, it is preferable to adopt a means using a direct current sputtering method, particularly a direct current magnetron sputtering apparatus. Since the relative density of the sputtering target of the present invention is as high as 98% or more, the occurrence of arcing and nodules is suppressed even when the direct current sputtering method is used.
  • a film having high crystallinity can be obtained even when the substrate temperature during sputtering is 150 ° C. or lower.
  • a film is formed on a resin substrate such as a transparent plastic substrate, a high transmittance can be obtained.
  • the conditions for forming the oxide sintered body of the present invention as a sputtering target are not particularly limited except for the substrate temperature, and can be formed under normal conditions.
  • a target-substrate distance 35 mm to 120 mm
  • ultimate vacuum 1 ⁇ 10 ⁇ 3 Pa or less
  • introduced gas 0% to 10% O 2 gas.
  • the substrate temperature may be lower than 150 ° C. by not heating from room temperature, or the substrate may be cooled and held at a predetermined temperature lower than 150 ° C. as necessary.
  • the transparent conductive film of the present invention is a transparent conductive film containing indium oxide as a main component and containing tin oxide and cobalt oxide, and an atomic ratio of Sn to In: Sn / In is 0.019 to 0.102, and the atomic ratio of each component to the sum of In, Sn, and Co: In / (In + Sn + Co) is 0.771 to 0.967, and Sn / (In + Sn + Co) is 0 .016 to 0.091, Co / (In + Sn + Co) is 0.015 to 0.15, and the specific resistance is 5 ⁇ 10 ⁇ 3 ⁇ ⁇ cm or less.
  • the specific resistance of the transparent conductive film is preferably 1 ⁇ 10 ⁇ 3 ⁇ ⁇ cm or less.
  • the composition of the transparent conductive film may depend on the film formation conditions, it can usually be the same as the composition of the oxide sintered body used as the film formation material by appropriate setting. That is, by determining the composition of the oxide sintered body based on the composition of the transparent conductive film, a transparent conductive film having a desired composition can be obtained by film formation.
  • the transparent conductive film of the present invention when the film thickness is 15 nm to 40 nm and the transmittance is measured with a spectrophotometer or spectroscopic ellipsometry using visible light of 400 nm to 800 nm, the average transmittance is a single film. Is 98% or more.
  • the substrate is formed without heating, it becomes a crystalline transparent conductive film having high crystallinity.
  • the transparent conductive film of the present invention is mainly oriented in the (222) plane and has a very high crystallinity.
  • the resistance change rate is within 1.2, preferably 1.0 or less. Such characteristics are particularly effective when a product to which the transparent conductive film is applied is used outdoors in a high temperature environment, or when an in-vehicle electronic device is applied.
  • Example 1 As raw material powders, indium oxide (In 2 O 3 ) powder (purity 99.9%, average particle size of about 0.9 ⁇ m), tin oxide (SnO 2 ) powder (purity 99.9%, average particle size of about 0.9 ⁇ m) ), And cobalt oxide (CoO) powder (purity 99.9%, average particle size of about 0.8 ⁇ m).
  • indium oxide (In 2 O 3 ) powder purity 99.9%, average particle size of about 0.9 ⁇ m
  • tin oxide (SnO 2 ) powder purity 99.9%, average particle size of about 0.9 ⁇ m
  • CoO cobalt oxide
  • this compact was placed in a sintering furnace (manufactured by Marusho Denki Co., Ltd.), and oxygen was circulated at a rate of 100 L / min per 1 m 3 of the furnace volume, thereby maintaining the oxygen concentration at 30% or more.
  • the state was heated to 700 ° C., and the binder removal treatment was performed for 34 hours. Thereafter, firing was performed for 20 hours by setting the atmosphere in the furnace to an air atmosphere and a maximum temperature of 1550 ° C. to obtain a sintered body.
  • the above sintered body was ground to produce an indium oxide sputtering target having a diameter of 4 inches (101.6 mm) and a thickness of 5 mm.
  • an ICP emission spectrometer ICPS8100, manufactured by Shimadzu Corporation
  • the composition range and sintering temperature of the raw material powder of Example 1 are shown in Table 1.
  • the relative density and specific resistance of the sintered body were measured for the obtained indium oxide-based sputtering target.
  • the specific resistance of the oxide sintered body was measured using a four-point probe resistivity meter Loresta EP (Dia Instruments, MCP-T360 type). As a result, the specific resistance of the sputtering target of Example 1 was 4.0 ⁇ 10 ⁇ 3 ⁇ ⁇ cm.
  • the obtained sputtering target was metal-bonded to an oxygen-free copper backing plate, set in a magnetron sputtering apparatus (made by Tokki Co., Ltd.) using a DC power source, sputtered under the following conditions, and a transparent conductive film having a film thickness of 25 nm. A membrane was obtained.
  • a glass substrate was used, and the film was formed without heating the substrate.
  • Crystallinity of transparent conductive film The crystallinity of the obtained transparent conductive oxide film was confirmed using a multipurpose X-ray diffractometer (Spectres, Inc., X'Pert-PRO MPD). When a diffraction peak on the (222) plane was observed, a crystalline film was obtained, and when no diffraction peak was observed, it was determined that the film was not crystallized. As a result, it was confirmed that the transparent conductive film of Example 1 had high crystallinity.
  • Transmissivity of transparent conductive film With respect to the obtained transparent conductive oxide film, the transmittance of light having a wavelength of 400 nm to 800 nm was measured using a spectrophotometer (manufactured by JASCO Corporation, UbestV-570iRM / DS). A transmittance peak was observed at a wavelength of 500 nm to 600 nm. The average transmittance at wavelengths of 400 nm to 800 nm was 98.2%.
  • the specific resistance of the transparent conductive film was calculated from the product of the surface resistance and the film thickness measured with a four-probe resistivity meter Loresta EP (manufactured by Dia Instruments, MCP-T360 type).
  • the film thickness of the transparent conductive film was determined by measuring the level difference between the non-deposited portion and the deposited portion using a contact-type surface roughness meter (manufactured by Tencor).
  • Example 1 was 3.0 ⁇ 10 ⁇ 3 ⁇ ⁇ cm, and the resistance change rate was 1.20.
  • Table 2 shows the measurement results of the relative density and specific resistance of the sputtering target of Example 1, the crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
  • Examples 2 to 8 A sputtering target was obtained in the same manner as in Example 1 except that the composition ratio of each component was changed to the values described in Table 1. About these sputtering targets, when the composition analysis was conducted by ICP emission spectroscopy, it was confirmed that all were the same as the composition ratio of the raw material powder as in Example 1. Moreover, when the composition analysis was conducted on the transparent conductive film formed using these sputtering targets using an ICP emission spectrophotometer, it was found that all of them were the same as the composition ratio of the sputtering target as in Example 1. confirmed.
  • Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Examples 2 to 8, crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
  • Comparative Examples 1 and 2 A sputtering target was obtained in the same manner as in Example 1 except that the composition ratio of each component was changed to the values described in Table 1.
  • Sn / In and Sn / (In + Sn + Co) are below the range of the present invention, and In / (In + Sn + Co) is above the range of the present invention.
  • Comparative Example 2 is an example in which Sn / In and Sn / (In + Sn + Co) are below the range of the present invention.
  • Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Comparative Examples 1 and 2 and the crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
  • Comparative Examples 3 to 5 An oxide sintered body was obtained in the same manner as in Example 1 except that the composition ratio of each component was changed to the values described in Table 1. Comparative Example 3 is an example in which Sn / In and Sn / (In + Sn + Co) both exceed the scope of the present invention. Comparative Example 4 is an example in which Sn / In exceeds the range of the present invention and In / (In + Sn + Co) falls below the range of the present invention. Comparative Example 5 is an example in which only Sn / In exceeds the scope of the present invention.
  • Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Comparative Examples 3 to 5, crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
  • Example 6 An oxide sintered body was obtained in the same manner as in Example 4 except that the firing temperature was 1400 ° C. All of these sputtering targets and transparent conductive films were also confirmed to have the same composition ratio as the raw material powder. Table 2 shows the measurement results of the relative density and specific resistance of the sputtering target of Comparative Example 6, the crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
  • Comparative Examples 7 and 8 An oxide sintered body was obtained in the same manner as in Example 1 except that the composition ratio of each component was changed to the values described in Table 1.
  • Comparative Example 7 In / (In + Sn + Co) exceeds the range of the present invention, and Co / (In + Sn + Co) falls below the range of the present invention.
  • Comparative Example 8 In / (In + Sn + Co) falls below the range of the present invention, and Co / (In + Sn + Co) exceeds the range of the present invention.
  • Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Comparative Examples 7 and 8, crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
  • Comparative Examples 9 to 14 oxide sintered bodies were obtained in the same manner as in Examples 1 to 6, respectively, except that at least one raw material powder having an average particle size of 1.0 ⁇ m or more was used. All of these sputtering targets and transparent conductive films were also confirmed to have the same composition ratio as the raw material powder.
  • Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Comparative Examples 9 to 14, crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
  • the sputtering target of Comparative Examples 1 and 2 with a small Sn content does not have a relative density of 98% or more, and the specific resistance exceeds 5 ⁇ 10 ⁇ 3 ⁇ ⁇ cm.
  • the transparent conductive film obtained by using the film had insufficient transmittance, specific resistance, and resistance change rate.
  • Comparative Examples 3 to 5 having a high Sn content it was understood that the transparent conductive film had poor crystallinity and the effect of promoting crystallization by adding cobalt oxide was reduced.
  • Comparative Examples 1, 2, 6, 7, and 9 to 14 in which the relative density of the sputtering target is less than 98% are compared with those in Examples 1 to 9 during arcing and Many nodules were observed, confirming deterioration of film properties and reduction of production efficiency.
  • the oxide sintered body of the present invention requires high transmittance such as a transparent conductive film for solar cells, a transparent conductive film for touch panels, a transparent conductive film for liquid crystal display devices such as a flat panel display, and an organic EL transparent conductive film.
  • a transparent conductive film for solar cells a transparent conductive film for solar cells
  • a transparent conductive film for touch panels a transparent conductive film for liquid crystal display devices
  • an organic EL transparent conductive film organic EL transparent conductive film.
  • it is suitable as a sputtering target for obtaining a transparent conductive film in a film touch panel application for which a transparent plastic film substrate is required by a direct current sputtering method.

Abstract

[Problem] To provide a crystalline transparent conductive film having a high transmittance of at least 98% in the visible wavelengths (400-800 nm) and a specific resistance of no greater than 5×10-3 Ω·cm, even resulting from film formation at a low substrate temperature of no greater than 150°C. [Solution] The transparent conductive film is obtained by means of film formation with the sputtering target being an oxide sintered body such that Sn/In is 0.019-0.102, In/(In+Sn+Co) is 0.771-0.967, Sn/(In+Sn+Co) is 0.016-0.091, Co/(In+Sn+Co) is 0.015-0.15, the relative density is at least 98%, and the specific resistance is no greater than 5×10-3 Ω·cm.

Description

酸化物焼結体およびその製造方法並びに酸化物透明導電膜Oxide sintered body, method for producing the same, and oxide transparent conductive film
　本発明は、タッチパネル、電子ペーパーなどの表示素子、太陽電池、および、発光ダイオード（ＬＥＤ）、有機エレクトロルミネッセンス（ＥＬ）などの光デバイスに用いられる酸化物透明導電膜、および、この酸化物透明導電膜を得るための酸化物焼結体およびその製造方法に関する。 The present invention relates to an oxide transparent conductive film used for a display element such as a touch panel, electronic paper, a solar cell, and an optical device such as a light emitting diode (LED) or an organic electroluminescence (EL), and the oxide transparent conductive film. The present invention relates to an oxide sintered body for obtaining a film and a method for producing the same.
　酸化物透明導電膜は、高い導電性と、特に可視光領域における高い透過率を有するため、タッチパネル、電子ペーパーなどの表示素子、太陽電池、および、ＬＥＤ、有機ＥＬなどの光デバイスにおける透明電極などの材料として広く利用されている。その他、自動車窓の熱線反射膜、帯電防止膜、防曇用透明発熱体などにも利用されている。 Since the oxide transparent conductive film has high conductivity and high transmittance particularly in the visible light region, display elements such as touch panels and electronic paper, solar cells, and transparent electrodes in optical devices such as LEDs and organic EL, etc. It is widely used as a material. In addition, it is also used for heat ray reflective films, antistatic films, and antifogging transparent heating elements for automobile windows.
　酸化物透明導電膜としては、主として、酸化インジウム系（Ｉｎ2Ｏ3＋α）の酸化物膜、酸化亜鉛系（ＺｎＯ＋α）の酸化物膜、酸化錫系（ＳｎＯ2＋α）の酸化物膜が広く知られている。これらのうち、酸化インジウム系の酸化物膜が最も多く使用されているが、その中でも酸化錫をドーパントとして含む酸化インジウム膜は、ＩＴＯ（Indium Tin Oxide）膜と称され、特に低抵抗の膜が容易に得られることから、主に使用されている。 As the oxide transparent conductive film, indium oxide (In 2 O 3 + α) oxide film, zinc oxide (ZnO + α) oxide film, and tin oxide (SnO 2 + α) oxide film are widely used. Are known. Of these, indium oxide-based oxide films are most often used. Among these, indium oxide films containing tin oxide as a dopant are called ITO (Indium Tin Oxide) films, and particularly low resistance films. It is mainly used because it can be easily obtained.
　これらの酸化物透明導電膜を製造する主な手段として、スパッタリング法が用いられている。スパッタリング法は、蒸気圧の低い材料の成膜や精密な膜厚制御が必要とされる際に有効な手法であって、操作が非常に簡便であることから、工業的にも広範に利用されている。 A sputtering method is used as a main means for manufacturing these transparent oxide conductive films. Sputtering is an effective technique when film formation of low vapor pressure materials and precise film thickness control are required, and its operation is very simple, so it is widely used industrially. ing.
　スパッタリング法では、一般に、約１０Ｐａ以下のガス圧のもとで、透明導電膜を成膜する基板を陽極とし、スパッタリングターゲットを陰極として、これらの間にグロー放電を起こしてアルゴンプラズマを発生させ、プラズマ中のアルゴン陽イオンを陰極のスパッタリングターゲットに衝突させ、これによって弾き飛ばされるターゲット成分の粒子を基板上に堆積させることにより、膜を形成している。 In the sputtering method, generally, under a gas pressure of about 10 Pa or less, a substrate on which a transparent conductive film is formed is used as an anode, a sputtering target is used as a cathode, glow discharge is generated between them, and argon plasma is generated. A film is formed by causing argon cations in the plasma to collide with the sputtering target of the cathode and depositing particles of the target component which are blown off by this on the substrate.
　スパッタリング法は、直流放電を利用する直流スパッタリング法と、高周波放電を利用する高周波スパッタリング法とに分類される。高周波スパッタリング法は、導電性ターゲットだけでなく、高抵抗ターゲットや、導電性材料と高抵抗材料が混合されたターゲットでも安定して成膜できるという利点を有するが、成膜速度が遅い、装置コストが高価などのデメリットを有している。一方、直流スパッタリング法は、装置価格が安価で、成膜操作も簡易であり、高速成膜に優れていることから、工業的には一般的に利用されている方法であるが、良質の導電性ターゲットを用いる必要がある。すなわち、導電性ターゲット内に微小の高抵抗物質が含まれていると、アルゴンイオンの照射で高抵抗物質が帯電して、成膜時にアーキングが発生してしまうため、このような高抵抗物質を含まない導電性ターゲットが必要とされる。 Sputtering methods are classified into a direct current sputtering method using direct current discharge and a high frequency sputtering method using high frequency discharge. The high-frequency sputtering method has an advantage that stable deposition can be performed not only on a conductive target but also on a high-resistance target or a target in which a conductive material and a high-resistance material are mixed, but the deposition rate is low and the apparatus cost is low. Has disadvantages such as high price. On the other hand, the direct current sputtering method is generally used industrially because it is inexpensive and has a simple film formation operation and is excellent in high-speed film formation. It is necessary to use sex targets. That is, if a minute high-resistance substance is included in the conductive target, the high-resistance substance is charged by irradiation with argon ions, and arcing occurs during film formation. A conductive target that does not include is required.
　直流スパッタリング法のうち、直流マグネトロンスパッタリング法は、ターゲットの裏側に磁石を置き、磁界をかけてターゲット近傍にγ電子を閉じ込めることにより、成膜速度が早いという利点を有している。ＩＴＯなどの酸化物透明導電膜を、直流マグネトロンスパッタリング法で形成する場合、基板の温度を上げないと十分に低い抵抗の膜を得ることができない。これは、成膜時の基板温度が高いほど、膜の結晶性と添加成分のドーピングが改善され、得られる膜の抵抗値が低下するためである。 Among the DC sputtering methods, the DC magnetron sputtering method has an advantage that the deposition rate is high by placing a magnet on the back side of the target and confining γ electrons in the vicinity of the target by applying a magnetic field. When an oxide transparent conductive film such as ITO is formed by DC magnetron sputtering, a sufficiently low resistance film cannot be obtained unless the temperature of the substrate is raised. This is because the higher the substrate temperature at the time of film formation, the better the crystallinity of the film and the doping of the additive components, and the lower the resistance value of the resulting film.
　さらに、近年、酸化物透明導電膜の用途の多様化に伴い、低抵抗化の要求に加えて、可視光領域における高い透過率や膜の十分な結晶化などが要求されるようになってきている。　たとえば、ＩＴＯにより、このような要求を満たした透明導電膜を得ようとする場合、ＩＴＯの結晶化温度が高いため、基板温度を２００℃程度まで上げる必要がある。しかしながら、透明導電膜の膜厚を１５ｎｍ～４０ｎｍ程度とした場合、可視波長（４００ｎｍ～８００ｎｍ）における平均透過率は、膜単体で９５％程度であり、基板込みでは８８％前後に留まっているのが現状である。 Furthermore, in recent years, with the diversification of applications of oxide transparent conductive films, in addition to the demand for low resistance, high transmittance in the visible light region and sufficient crystallization of films have been required. Yes. For example, when it is intended to obtain a transparent conductive film satisfying such requirements by using ITO, it is necessary to raise the substrate temperature to about 200 ° C. because the crystallization temperature of ITO is high. However, when the film thickness of the transparent conductive film is about 15 nm to 40 nm, the average transmittance at a visible wavelength (400 nm to 800 nm) is about 95% for the single film, and it remains around 88% including the substrate. Is the current situation.
　ＩＴＯ以外の材料として、特開２００５－２９０４５８号公報には、セリウムを含有した酸化インジウム系のスパッタリングターゲット材（Ｉｎ－Ｃｅ－Ｏ）と、このスパッタリングターゲットを用いて得られる透明導電膜に関する技術が開示されている。この透明導電膜は、非晶質で用いられることを前提としているが、基板温度を２００℃以上としたり、２００℃～２５０℃の温度で加熱したりすることにより、膜が結晶化することが示されている。 As a material other than ITO, Japanese Patent Laid-Open No. 2005-290458 discloses a technique relating to a cerium-containing indium oxide-based sputtering target material (In—Ce—O) and a transparent conductive film obtained using this sputtering target. It is disclosed. This transparent conductive film is assumed to be used in an amorphous state. However, when the substrate temperature is set to 200 ° C. or higher, or the substrate is heated at a temperature of 200 ° C. to 250 ° C., the film may be crystallized. It is shown.
　また、特開２００４－４３８５１号公報には、高い導電性と可視光領域での高い透過率を備える酸化物透明導電膜として、基板温度を２００℃以上に加熱して成膜することにより結晶性としたタングステンを含有した酸化インジウム膜（Ｉｎ－Ｗ－Ｏ）が開示されている。 JP 2004-43851 A discloses that an oxide transparent conductive film having high conductivity and high transmittance in the visible light region is formed by heating the substrate at a temperature of 200 ° C. or higher to form a crystallinity. An indium oxide film (In—W—O) containing tungsten is disclosed.
　すなわち、これらのＩｎ－Ｃｅ－ＯやＩｎ－Ｗ－Ｏを用いた透明導電膜でも、高い透過率や膜の十分な結晶化を図るためには、２００℃以上の温度での成膜や熱処理が必要とされている。 That is, even in a transparent conductive film using In—Ce—O or In—W—O, film formation or heat treatment at a temperature of 200 ° C. or higher is required in order to achieve high transmittance and sufficient crystallization of the film. Is needed.
　一方、近年のモバイル機器の発達により、デバイスの軽量化および低コスト化、安全性への要求が高まるにつれて、透明導電膜用の基板として、軽量かつ安価であり、割れないプラスチック板やプラスチックフィルムのような透明樹脂基板が多く用いられるようになってきている。これらの透明樹脂基板を用いる場合、基板を１５０℃以上に加熱することが難しく、結晶化した透明導電膜を形成することが困難となる。また、ガラス基板と比較した場合、透明樹脂基板は透過率が低いため、その上に透明導電膜を形成した場合に、全体として十分な透過率を得ることができないという問題もある。 On the other hand, with the development of mobile devices in recent years, as the demand for lighter and lower cost devices and safety has increased, as a substrate for transparent conductive films, lightweight and inexpensive plastic plates and plastic films that do not break Such a transparent resin substrate is often used. When these transparent resin substrates are used, it is difficult to heat the substrate to 150 ° C. or higher, and it becomes difficult to form a crystallized transparent conductive film. In addition, since the transparent resin substrate has a low transmittance when compared with a glass substrate, there is also a problem that a sufficient transmittance cannot be obtained as a whole when a transparent conductive film is formed thereon.
　特開平９－２０９１３４号公報および特開平９－１６１５４２号公報には、ＩＴＯよりも高抵抗の透明導電膜を直流スパッタリング法により得るため、ＩＴＯにチタン、イリジウム、コバルトなどの金属元素を添加した低抵抗のスパッタリングターゲットが開示されている。これらのスパッタリングターゲットを用いた場合、直流マグネトロンスパッタリング法により、基板温度を室温として成膜した場合であっても、透明導電膜が得られるとされている。 In JP-A-9-209134 and JP-A-9-161542, a transparent conductive film having a higher resistance than that of ITO is obtained by a direct current sputtering method. Therefore, a low-resistance metal element such as titanium, iridium, and cobalt is added to ITO. A resistive sputtering target is disclosed. When these sputtering targets are used, a transparent conductive film is obtained even when the substrate temperature is set to room temperature by direct current magnetron sputtering.
　しかしながら、これらのスパッタリングターゲットは、いずれも十分な相対密度および比抵抗を備えたものとはなっていない。また、得られる膜もその目的から本来的に高抵抗の傾向があり、これらの文献には、高い導電性と可視光領域での高い透過率を兼ね備えた酸化物透明導電膜およびそのような特性の膜を得るための条件は示されていない。 However, none of these sputtering targets has sufficient relative density and specific resistance. In addition, the resulting film also has a tendency of inherently high resistance for that purpose, and these documents include an oxide transparent conductive film having high conductivity and high transmittance in the visible light region, and such characteristics. The conditions for obtaining this film are not shown.
特開２００５－２９０４５８号公報JP 2005-290458 A 特開２００４－４３８５１号公報JP 2004-43851 A 特開平９－２０９１３４号公報JP-A-9-209134 特開平９－１６１５４２号公報JP-A-9-161542
　本発明は、上述のような問題に鑑み、高い導電性と可視光領域での高い透過率を兼ね備えた、十分な結晶性を備える酸化物透明導電膜を提供すること、および、このような特性を備えた酸化物透明導電膜を、透明樹脂基板を用いて、直流スパッタリング法により成膜することを可能とする酸化物焼結体を提供することを目的としている。 In view of the above problems, the present invention provides an oxide transparent conductive film having sufficient crystallinity, which has high conductivity and high transmittance in the visible light region, and such characteristics. It is an object of the present invention to provide an oxide sintered body capable of depositing an oxide transparent conductive film comprising a film by a direct current sputtering method using a transparent resin substrate.
　本発明の酸化物焼結体は、酸化インジウムを主成分とし、酸化スズおよび酸化コバルトを含有する酸化物焼結体であって、Ｉｎに対するＳｎの原子比：Ｓｎ／Ｉｎが０．０１９～０．１０２であり、かつ、Ｉｎ、ＳｎおよびＣｏの合計に対する各成分の原子比：Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．７７１～０．９６７、Ｓｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１６～０．０９１、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１５～０．１５であり、その相対密度が９８％以上であることを特徴とする。さらに、本発明の酸化物焼結体においては、その比抵抗が５×１０-3Ω・ｃｍ以下であることが好ましい。 The oxide sintered body of the present invention is an oxide sintered body containing indium oxide as a main component and containing tin oxide and cobalt oxide, and an atomic ratio of Sn to In: Sn / In is 0.019 to 0 .102, and the atomic ratio of each component to the sum of In, Sn, and Co: In / (In + Sn + Co) is 0.771 to 0.967, Sn / (In + Sn + Co) is 0.016 to 0.091, Co / (In + Sn + Co) is 0.015 to 0.15, and its relative density is 98% or more. Furthermore, in the oxide sintered body of the present invention, the specific resistance is preferably 5 × 10 −3 Ω · cm or less.
　本発明の酸化物焼結体を、スパッタリングターゲットとして用いることで、１５０℃以下の低い基板温度での成膜によっても、次のような特性の酸化物透明導電膜を得ることが可能となる。 By using the oxide sintered body of the present invention as a sputtering target, an oxide transparent conductive film having the following characteristics can be obtained even by film formation at a low substrate temperature of 150 ° C. or lower.
　なお、このような酸化物焼結体は、平均粒径がいずれも０．０５μｍ以上１．０μｍ未満である酸化インジウム粉、酸化スズ粉、酸化コバルト粉を原料粉末として用いて、この原料粉末に、水と水溶性バインダを配合し、得られたスラリーを粉砕し、１０時間以上撹拌した後、乾燥、造粒を行い、得られた造粒粉を型に詰め、加圧成形し、得られた成形体を、酸素雰囲気中、１４５０℃～１６００℃で１２時間～２５時間焼結することにより得ることができる。 Such an oxide sintered body uses indium oxide powder, tin oxide powder, and cobalt oxide powder having an average particle size of 0.05 μm or more and less than 1.0 μm as raw material powder. , Water and a water-soluble binder were blended, and the resulting slurry was pulverized, stirred for 10 hours or more, dried and granulated, and the resulting granulated powder was packed into a mold and pressure-molded to obtain The molded body can be obtained by sintering at 1450 ° C. to 1600 ° C. for 12 hours to 25 hours in an oxygen atmosphere.
　一方、本発明の酸化物透明導電膜は、酸化インジウムを主成分とし、酸化スズおよび酸化コバルトを含有する透明導電膜であって、Ｉｎに対するＳｎの原子比：Ｓｎ／Ｉｎが０．０１９～０．１０２であり、かつ、Ｉｎ、ＳｎおよびＣｏの合計に対する各成分の原子比：Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．７７１～０．９６７、Ｓｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１６～０．０９１、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１５～０．１５であり、比抵抗が５×１０-3Ω・ｃｍ以下であることを特徴とする。 On the other hand, the oxide transparent conductive film of the present invention is a transparent conductive film containing indium oxide as a main component and containing tin oxide and cobalt oxide, and the atomic ratio of Sn to In: Sn / In is 0.019 to 0 .102, and the atomic ratio of each component to the sum of In, Sn, and Co: In / (In + Sn + Co) is 0.771 to 0.967, Sn / (In + Sn + Co) is 0.016 to 0.091, Co / (In + Sn + Co) is 0.015 to 0.15, and the specific resistance is 5 × 10 −3 Ω · cm or less.
　本発明の酸化物透明導電膜においては、さらに、膜厚を１５ｎｍ～４０ｎｍとした場合、波長４００ｎｍ～８００ｎｍにおける膜単体の平均透過率が９８％以上となることが好ましい。また、温度が９５℃、湿度が９５％の環境に、１０００時間さらした場合であっても、その抵抗変化率は１．２以内となることが好ましい。 In the oxide transparent conductive film of the present invention, when the film thickness is 15 nm to 40 nm, it is preferable that the average transmittance of a single film at a wavelength of 400 nm to 800 nm is 98% or more. Moreover, even if it is a case where it exposes to the environment of temperature 95 degreeC and humidity 95% for 1000 hours, it is preferable that the resistance change rate will be 1.2 or less.
　本発明の酸化物焼結体をスパッタリングターゲットとして用いて、直流スパッタリング法により、１５０℃以下の低い基板温度で成膜した場合であっても、比抵抗が５×１０-3Ω・ｃｍ以下という低抵抗であり、かつ、可視波長４００ｎｍ～８００ｎｍにおける膜単体の平均透過率が９８％以上という高い透過率を備えた、結晶性の高い酸化物透明導電膜を得ることができる。すなわち、成膜時の基板として、透明樹脂基板を用いた場合でも、低抵抗かつ高い透過率を備えた結晶性の酸化物透明導電膜の成膜が可能となる。 Even when the oxide sintered body of the present invention is used as a sputtering target and formed by a direct current sputtering method at a low substrate temperature of 150 ° C. or less, the specific resistance is 5 × 10 −3 Ω · cm or less. A highly crystalline transparent oxide conductive film having a low resistance and a high transmittance such that the average transmittance of a single film at a visible wavelength of 400 nm to 800 nm is 98% or more can be obtained. That is, even when a transparent resin substrate is used as a substrate during film formation, a crystalline oxide transparent conductive film having low resistance and high transmittance can be formed.
　また、本発明の酸化物焼結体は、相対密度が高く、低抵抗であるため、直流スパッタリング法による酸化物透明導電膜の成膜において、スパッタリングターゲットとして用いた場合でも、成膜時におけるアーキング、およびこれに起因するノジュールやパーティクルの発生を防止することができる。 In addition, since the oxide sintered body of the present invention has a high relative density and low resistance, even when used as a sputtering target in the formation of an oxide transparent conductive film by a direct current sputtering method, arcing during film formation is performed. , And the generation of nodules and particles due to this can be prevented.
　以下、本発明について、（１）酸化物焼結体、（２）酸化物焼結体の製造方法、（３）透明導電膜の成膜、（４）透明導電膜に分けて詳述する。 Hereinafter, the present invention will be described in detail by dividing into (1) oxide sintered body, (2) manufacturing method of oxide sintered body, (3) film formation of transparent conductive film, and (4) transparent conductive film.
　（１）酸化物焼結体
　本発明者らは、酸化インジウム系酸化物焼結体について鋭意研究を重ねた結果、ａ）酸化インジウム、酸化スズに加えて、酸化コバルトを添加し、かつ、これらの酸化物を構成する、インジウム（Ｉｎ）、スズ（Ｓｎ）、コバルト（Ｃｏ）の各金属成分の組成比率を所定の範囲内に規制するとともに、所定の製造条件で酸化物焼結体を作製することにより、得られる酸化物焼結体の密度を上昇させ、その焼結体組織の緻密化を図ることが可能となること、ｂ）本発明の酸化物焼結体をスパッタリングターゲットとして用いることにより、直流スパッタリング法でも、成膜時にアーキングを発生させることなく、かつ、１５０℃以下という低い基板温度でも、結晶性で、その比抵抗が５×１０-3Ω・ｃｍ以下という低抵抗であり、かつ、可視波長４００ｎｍ～８００ｎｍにおける膜単体の平均透過率が９８％以上という高い透過率を備える酸化物透明導電膜を得ることができること、ｃ）さらに、本発明の酸化物透明導電膜は、低抵抗かつ高い透過率を備えるとともに、高温高湿環境下（温度９５℃、湿度９５％、１０００ｈ）においても、抵抗変化が少ない優れた安定性を有すること、という知見を得て、本発明を完成するに至ったものである。 (1) Oxide sintered body As a result of intensive studies on indium oxide-based oxide sintered bodies, the inventors have added a cobalt oxide in addition to indium oxide and tin oxide, and these The composition ratio of each metal component of indium (In), tin (Sn), and cobalt (Co) constituting the oxide is regulated within a predetermined range, and an oxide sintered body is manufactured under predetermined manufacturing conditions. By doing so, it becomes possible to increase the density of the obtained oxide sintered body and to make the sintered body texture dense, and b) to use the oxide sintered body of the present invention as a sputtering target. Accordingly, even in a DC sputtering method, without causing arcing during film formation, and, even at a low substrate temperature of 0.99 ° C. or less, a crystalline, low resistance that its specific resistance 5 × 10 -3 Ω · cm or less And an oxide transparent conductive film having a high transmittance such that the average transmittance of a single film at a visible wavelength of 400 nm to 800 nm is 98% or more, and c). The present invention has obtained the knowledge that it has low resistance and high transmittance and has excellent stability with little resistance change even in a high temperature and high humidity environment (temperature 95 ° C., humidity 95%, 1000 h). Has been completed.
　まず、本発明の酸化物焼結体では、酸化スズの含有量を、Ｉｎに対するＳｎの原子比：Ｓｎ／Ｉｎで０．０１９～０．１０２の範囲内となるように規制している。酸化スズの含有量がＳｎ／Ｉｎで０．０１９未満では、焼結体の相対密度が９８％以上とならなくなってしまい、かつ、焼結体の比抵抗も５×１０-3Ω・ｃｍ以下にならなくなってしまう。また、このような酸化スズの含有量が少ない焼結体を用いて成膜した透明導電膜では、膜の平均透過率が９８％以上とならないばかりか、膜の比抵抗も５×１０-3Ω・ｃｍとならず、かつ、高温高湿環境下における抵抗変化率が１．２を超えてしまう。一方、酸化スズの含有量がＳｎ／Ｉｎで０．１０２を超えると、成膜後の酸化物透明導電膜が１５０℃以下の基板温度では結晶化せず、かつ、得られた膜の平均透過率が９８％以上とならなくなってしまう。酸化スズの含有量は、Ｓｎ／Ｉｎで０．０４０～０．１０２の範囲内であることが好ましい。 First, in the oxide sintered body of the present invention, the content of tin oxide is regulated so as to be within a range of 0.019 to 0.102 in terms of Sn / In atomic ratio of Sn. If the tin oxide content is less than 0.019 Sn / In, the relative density of the sintered body will not be 98% or more, and the specific resistance of the sintered body will be 5 × 10 −3 Ω · cm or less. It will not become. Further, in the transparent conductive film formed using such a sintered body having a small content of tin oxide, the average transmittance of the film does not become 98% or more, and the specific resistance of the film is also 5 × 10 −3. It does not become Ω · cm, and the resistance change rate in a high temperature and high humidity environment exceeds 1.2. On the other hand, when the content of tin oxide exceeds 0.102 in Sn / In, the oxide transparent conductive film after film formation does not crystallize at a substrate temperature of 150 ° C. or lower, and the average transmission of the obtained film The rate will not be over 98%. The tin oxide content is preferably in the range of 0.040 to 0.102 in terms of Sn / In.
　ただし、このような特性は、酸化インジウムに対する酸化スズの添加のみでは十分に得られるものではなく、さらに酸化コバルトを含有させることにより得られるものである。すなわち、本発明の酸化物焼結体では、酸化インジウム、酸化スズおよび酸化コバルトの含有量を、Ｉｎ、ＳｎおよびＣｏの合計に対する各金属成分の原子比：Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）で０．７７１～０．９６７、Ｓｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）で０．０１６～０．０９１、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）で０．０１５～０．１５となるように、それぞれ規制している。 However, such characteristics cannot be obtained sufficiently only by adding tin oxide to indium oxide, but can be obtained by further adding cobalt oxide. That is, in the oxide sintered body of the present invention, the content of indium oxide, tin oxide, and cobalt oxide is 0.771 to the atomic ratio of each metal component to the total of In, Sn, and Co: In / (In + Sn + Co) The regulation is 0.967, Sn / (In + Sn + Co) is 0.016 to 0.091, and Co / (In + Sn + Co) is 0.015 to 0.15.
　このように、所定量の酸化コバルトを含有させることにより、酸化物焼結体の密度が上昇し、焼結体組織の緻密化が図られるとともに、結晶性を向上させ、結晶配向性を一定方向に制御することができる。この酸化コバルトの作用により、酸化スズの含有量を規制したことによる、酸化物透明導電膜における、低抵抗かつ高い透過率という特性が安定して得られるとともに、特に、高温高湿環境下における抵抗変化率が１．２以下という優れた安定性がもたらされる。 Thus, by containing a predetermined amount of cobalt oxide, the density of the oxide sintered body is increased, the sintered body structure is densified, the crystallinity is improved, and the crystal orientation is in a certain direction. Can be controlled. Due to the action of this cobalt oxide, it is possible to stably obtain the characteristics of low resistance and high transmittance in the oxide transparent conductive film by regulating the content of tin oxide, and in particular, resistance in a high temperature and high humidity environment. Excellent stability with a change rate of 1.2 or less is brought about.
　酸化コバルトの含有量は、Ｃｏの、Ｉｎ、ＳｎおよびＣｏの合計に対する原子比：Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）で、０．０１５～０．１５とすることが必要である。酸化コバルトの含有量がＣｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）で０．０１５未満の場合には、酸化物焼結体の密度が十分に高くならず、焼結体の比抵抗も高いものとなる。この場合、得られる透明導電膜は、結晶性を有するものの、比抵抗は高くなる傾向にあり、かつ、その安定性が十分なものではなくなる。一方、酸化コバルトの含有量がＣｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）で０．１５を超える場合には、高密度で低抵抗の酸化物焼結体が得られるものの、透明導電膜の結晶化温度が上昇するため、低い基板温度では、結晶化しにくくなるとともに、成膜後の膜の抵抗変化が不安定なものとなってしまう。なお、酸化コバルトの含有量は、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）で０．０５～０．１５の範囲であることが好ましい。また、酸化インジウムの含有量は、Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）で０．７７１～０．９６７の範囲、酸化スズの含有量は、Ｓｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）で０．０１６～０．０９１の範囲であることが好ましい。 The cobalt oxide content needs to be 0.015 to 0.15 in terms of the atomic ratio of Co to the total of In, Sn and Co: Co / (In + Sn + Co). When the content of cobalt oxide is Co / (In + Sn + Co) and less than 0.015, the density of the oxide sintered body is not sufficiently high, and the specific resistance of the sintered body is also high. In this case, although the obtained transparent conductive film has crystallinity, the specific resistance tends to be high, and the stability is not sufficient. On the other hand, when the content of cobalt oxide exceeds 0.15 in Co / (In + Sn + Co), a high-density, low-resistance oxide sintered body can be obtained, but the crystallization temperature of the transparent conductive film increases. When the substrate temperature is low, crystallization is difficult and the resistance change of the film after film formation becomes unstable. The cobalt oxide content is preferably in the range of 0.05 to 0.15 in terms of Co / (In + Sn + Co). The content of indium oxide is 0.771 to 0.967 in In / (In + Sn + Co), and the content of tin oxide is 0.016 to 0.091 in Sn / (In + Sn + Co). Is preferred.
　また、本発明の酸化物焼結体は、スパッタリング中に発生するアーキング、およびこれに起因するノジュールやパーティクルの発生など、膜の特性に影響を与える原因を有効に防止する観点から、その相対密度を９８％以上とする必要があり、９９％以上とすることがより好ましい。 In addition, the oxide sintered body of the present invention has a relative density from the viewpoint of effectively preventing the arcing generated during sputtering and the causes affecting the film properties such as the generation of nodules and particles resulting therefrom. Needs to be 98% or more, more preferably 99% or more.
　本発明では、酸化物焼結体の組成比率を上述のように規制するとともに、その相対密度を９８％以上とすることにより、酸化物焼結体の比抵抗（体積抵抗率）を５×１０-3Ω・ｃｍ以下、好ましくは１．０×１０-3Ω・ｃｍ以下となるようにしている。すなわち、本発明に規定する範囲よりも、低い相対密度、高い比抵抗の酸化物焼結体を用いた場合、高温環境下における抵抗変化率が悪化し、膜の安定性が劣るとともに、さらには膜の透過率が低くなり、かつ、膜の比抵抗も高いものとなる。 In the present invention, the specific ratio (volume resistivity) of the oxide sintered body is set to 5 × 10 5 by regulating the composition ratio of the oxide sintered body as described above and setting the relative density to 98% or more. −3 Ω · cm or less, preferably 1.0 × 10 −3 Ω · cm or less. That is, when an oxide sintered body having a lower relative density and a higher specific resistance than the range defined in the present invention is used, the rate of change in resistance under a high temperature environment deteriorates, and the stability of the film deteriorates. The transmittance of the film is lowered and the specific resistance of the film is also increased.
　（２）酸化物焼結体の製造方法
　上述のような特性を備える、本発明の酸化物焼結体の製造する際には、酸化インジウム（Ｉｎ2Ｏ3）粉、酸化スズ（ＳｎＯ2）粉、酸化コバルト（ＣｏＯ）粉とからなる原料粉末に、水と水溶性バインダを配合し、得られたスラリーを粉砕し、１０時間以上攪拌した後、乾燥、造粒を行う。その後、得られた造粒粉を型に詰め、加圧成形し得られた成形体を、酸素含有雰囲気中、１４５０℃～１６００℃で１２時間～２５時間焼結することが必要である。以下、各工程について詳述に説明する。 (2) Manufacturing method of oxide sintered body When manufacturing the oxide sintered body of the present invention having the above-described characteristics, indium oxide (In 2 O 3 ) powder, tin oxide (SnO 2 ) Water and a water-soluble binder are blended in a raw material powder composed of powder and cobalt oxide (CoO) powder, and the resulting slurry is pulverized, stirred for 10 hours or more, and then dried and granulated. Thereafter, the obtained granulated powder is packed in a mold, and the molded body obtained by pressure molding must be sintered at 1450 ° C. to 1600 ° C. for 12 to 25 hours in an oxygen-containing atmosphere. Hereinafter, each step will be described in detail.
　（２－１）原料粉末
　本発明に係る酸化物焼結体の原料としては、酸化インジウム粉、酸化スズ粉および酸化コバルト粉を使用することができ、これらの粉末の平均粒径は、いずれも０．０５μｍ以上１．０μｍ未満であることが必要である。好ましくは、これらの粉末の平均粒径は、０．１μｍ以上０．８μｍ未満の範囲内である。 (2-1) Raw material powder As a raw material of the oxide sintered body according to the present invention, indium oxide powder, tin oxide powder and cobalt oxide powder can be used. It is necessary to be 0.05 μm or more and less than 1.0 μm. Preferably, the average particle size of these powders is in the range of 0.1 μm or more and less than 0.8 μm.
　平均粒径が０．０５μｍ未満の場合には、粉末が凝集して、均一に混合することが困難となる。一方、１．０μｍ以上になると、得られる酸化物焼結体において、相対密度を９８％以上とすることができなくなる。このため、スパッタリング中に発生するアーキングが発生し、これに起因するノジュールやパーティクルの発生などに起因して、膜の特性が悪化してしまう。 When the average particle size is less than 0.05 μm, the powder aggregates and it becomes difficult to mix uniformly. On the other hand, if the thickness is 1.0 μm or more, the resulting oxide sintered body cannot have a relative density of 98% or more. For this reason, arcing generated during sputtering occurs, and the characteristics of the film deteriorate due to generation of nodules and particles resulting from the arcing.
　なお、これらの粉末の混合比は、目的とする酸化物焼結体の組成比率、すなわち各金属成分の原子比に応じたものとすればよい。具体的には、Ｉｎに対するＳｎの原子比：Ｓｎ／Ｉｎが０．０１９～０．１０２となるようにし、かつ、Ｉｎ、ＳｎおよびＣｏの合計に対する各成分の原子比：Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．７７１～０．９６７、Ｓｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１６～０．０９１、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１５～０．１５となるように調合すればよい。 The mixing ratio of these powders may be determined according to the composition ratio of the target oxide sintered body, that is, the atomic ratio of each metal component. Specifically, the atomic ratio of Sn to In: Sn / In is set to 0.019 to 0.102, and the atomic ratio of each component to the total of In, Sn, and Co: In / (In + Sn + Co) is Preparation may be made so that 0.771 to 0.967, Sn / (In + Sn + Co) is 0.016 to 0.091, and Co / (In + Sn + Co) is 0.015 to 0.15.
　（２－２）湿式粉砕工程
　次に、これらの原料粉末に対して、水溶性バインダを０．５質量％～１．５質量％となるように加え、さらに水とともに樹脂製ポットに入れ、湿式粉砕および混合を行う。水溶性バインダとしては、加熱により消失または気化する公知のバインダであれば限定されず、たとえば、ポリビニルアルコール（ＰＶＡ）、ポリビニルブチラール、メチルセルロースなどを使用することが可能である。 (2-2) Wet pulverization step Next, a water-soluble binder is added to these raw material powders in an amount of 0.5 to 1.5% by mass, and is further placed in a resin pot together with water. Grind and mix. The water-soluble binder is not limited as long as it is a known binder that disappears or vaporizes by heating, and for example, polyvinyl alcohol (PVA), polyvinyl butyral, methyl cellulose, and the like can be used.
　また、この工程には、ボールミル、ビーズミルなど公知の手段を用いることができる。コストの面ではボールミルを採用することが好ましいが、ボールミルでは粉砕時間が非常に掛かるため、作業効率の面からは、ビーズミルを使用することが好ましい。ボールやビーズとしては、たとえば、硬質のジルコニア（ＺｒＯ2）製のものを用いることが好ましい。また、ボール径またはビーズ径によっても粉砕性が変わることから、ボールの場合にはφ２ｍｍ～φ６ｍｍ程度、ビーズの場合にはφ０．２ｍｍ～φ０．７ｍｍ程度のものを用いることが好ましい。ボール径またはビーズ径が上記範囲を外れる場合には、所定の粉砕能力が得ることが出来ず、量産性や品質が低下する可能性がある。 Moreover, well-known means, such as a ball mill and a bead mill, can be used for this process. Although it is preferable to use a ball mill in terms of cost, it is preferable to use a bead mill from the viewpoint of work efficiency because the ball mill takes much time to grind. As the balls and beads, for example, those made of hard zirconia (ZrO 2 ) are preferably used. In addition, since the grindability changes depending on the ball diameter or bead diameter, it is preferable to use a ball having a diameter of about φ2 mm to φ6 mm and a bead of about φ0.2 mm to φ0.7 mm. When the ball diameter or the bead diameter is out of the above range, a predetermined crushing ability cannot be obtained, and mass productivity and quality may be lowered.
　湿式粉砕および混合の条件は、ボールミルの場合には回転数を５０ｒｐｍ～７０ｒｐｍとして、粉砕・混合時間を１５時間～２８時間とすることが好ましい。また、ビーズミルの場合には回転数を１３００ｒｐｍ～１７００ｒｐｍとして、粉砕・混合時間を３時間～６時間とすることが好ましい。粉砕および混合の時間が不足すると、最終的に得られる焼結体密度が低下する。逆に長すぎても、ジルコニアが不純物として混入して、同様に焼結体密度が低下する。 In the case of a ball mill, the wet pulverization and mixing conditions are preferably 50 to 70 rpm and a pulverization / mixing time of 15 to 28 hours. In the case of a bead mill, the number of rotations is preferably 1300 rpm to 1700 rpm, and the pulverization / mixing time is preferably 3 hours to 6 hours. When the time for pulverization and mixing is insufficient, the sintered body density finally obtained decreases. On the other hand, if it is too long, zirconia is mixed as an impurity, and the density of the sintered body similarly decreases.
　以上の処理により、平均粒径が０．５μｍ以下の原料粉末を含むスラリーが得られる。平均粒径が０．５μｍを超える場合には、密度低下という問題が生ずる。この平均粒径は、０．１μｍ～０．５μｍの範囲にあるようにすることが好ましい。また、生産性の観点から、スラリーの粘度は３０ｍＰａ・ｓ～６００ｍＰａ・ｓとすることが好ましい。 Through the above treatment, a slurry containing raw material powder having an average particle size of 0.5 μm or less is obtained. When the average particle diameter exceeds 0.5 μm, a problem of density reduction occurs. The average particle diameter is preferably in the range of 0.1 μm to 0.5 μm. From the viewpoint of productivity, the viscosity of the slurry is preferably 30 mPa · s to 600 mPa · s.
　（２－３）噴霧乾燥工程
　前記工程により得られた原料粉末を含むスラリーについて、噴霧乾燥を行い、造粒粉を得る。特に、スプレードライヤを用いることにより、球状の造粒粉を得ることが好ましい。なお、噴霧乾燥時の乾燥温度は、１２０℃～２００℃の範囲とすることが好ましい。また、装置に応じて、球状の造粒粉が得られるように排風量などにより乾燥速度を適宜調整することが好ましい。噴霧乾燥には、量産性に優れたディスクを用いたスプレードライヤを用いることが好ましく、ディスク回転数：８０００ｒｐｍ～１５０００ｒｐｍ、スラリー濃度４０％以上とすることで、球状の成形性に優れる造粒粉が得られる。乾燥温度を低くすることで、バインダが硬くならず、成形時に近接する粒同士が変形および密着することで、高強度の成形体が得られる。造粒粉の粒径は、平均粒径で４０μｍ～１００μｍとすることが望ましい。 (2-3) Spray drying step The slurry containing the raw material powder obtained in the above step is spray dried to obtain granulated powder. In particular, it is preferable to obtain a spherical granulated powder by using a spray dryer. The drying temperature during spray drying is preferably in the range of 120 ° C to 200 ° C. Further, it is preferable to appropriately adjust the drying speed according to the amount of exhaust air so that spherical granulated powder can be obtained according to the apparatus. For spray drying, it is preferable to use a spray dryer using a disk having excellent mass productivity. By setting the disk rotation speed to 8000 rpm to 15000 rpm and a slurry concentration of 40% or more, a granulated powder having excellent spherical formability can be obtained. can get. By lowering the drying temperature, the binder does not become hard, and the grains close to each other at the time of molding are deformed and adhered to each other, whereby a high-strength molded product is obtained. The particle size of the granulated powder is desirably 40 μm to 100 μm in terms of average particle size.
　（２－４）成形工程
　噴霧乾燥工程を経て得られた造粒粉を、ゴム型に充填し、冷間静水圧プレス（ＣＩＰ）を用いて、２５０ＭＰａ～３５０ＭＰａの圧力、より好ましくは２８０ＭＰａ～３２０ＭＰａの圧力で、成形を行う。この際、一軸プレスによる予備成形を実施した後に、ＣＩＰを行ってもよい。成形圧力が２５０ＭＰａ未満の場合には、造粒粉同士の間に空孔ができ、酸化物焼結体の相対密度を９８％以上とすることができない。一方、３５０ＭＰａを越えても、それ以上の効果を得ることができず、また、装置の耐久性の観点からも量産に適しているとはいえない。なお、成形時における最高圧力の保持時間は、１分～１０分とすることが好ましい。 (2-4) Molding Step The granulated powder obtained through the spray drying step is filled in a rubber mold and is subjected to a pressure of 250 MPa to 350 MPa, more preferably 280 MPa to 320 MPa, using a cold isostatic press (CIP). Molding is performed at a pressure of. At this time, CIP may be performed after preforming by uniaxial pressing. When the molding pressure is less than 250 MPa, pores are formed between the granulated powders, and the relative density of the oxide sintered body cannot be 98% or more. On the other hand, even if it exceeds 350 MPa, no further effect can be obtained, and it cannot be said that it is suitable for mass production from the viewpoint of durability of the apparatus. The maximum pressure holding time during molding is preferably 1 to 10 minutes.
　（２－５）脱バインダ工程
　次に、得られた成形体を焼結炉内に設置し、炉内の酸素濃度を３０体積％以上に維持した状態で、加熱（脱バインダ）を行う。この際、炉内の酸素の流通量は、成形体の大きさや形状に応じて適宜選択されるべきものであるが、９０Ｌ／分～１１０Ｌ／分程度の割合で炉内に酸素を流通させることが好ましい。 (2-5) Debinding Step Next, the obtained molded body is placed in a sintering furnace, and heating (debinding) is performed in a state where the oxygen concentration in the furnace is maintained at 30% by volume or more. At this time, the flow rate of oxygen in the furnace should be appropriately selected according to the size and shape of the molded body, but oxygen should be passed through the furnace at a rate of about 90 L / min to 110 L / min. Is preferred.
　このように炉内に酸素を流通させて酸素濃度を３０体積％以上に維持することにより、水溶性バインダが分解されて発生したガスが、酸素と共に炉外へ排出されるため、脱バインダを促進することができるばかりでなく、成形体表面が還元されることを抑制することができるため、高強度、高密度の焼結体を得ることができる。一方、酸素の流通量が十分でない場合、または、炉内の酸素濃度が不足する場合には、上記の効果を得ることができない。なお、酸素濃度は１００体積％（純酸素雰囲気）まで採用することができるが、コストの観点から３０体積％程度とすれば十分である。 By circulating oxygen in the furnace and maintaining the oxygen concentration at 30% by volume or more, the gas generated by decomposing the water-soluble binder is discharged out of the furnace together with oxygen, thus promoting binder removal. In addition to being able to suppress the reduction of the surface of the molded body, a high-strength and high-density sintered body can be obtained. On the other hand, when the oxygen circulation amount is not sufficient, or when the oxygen concentration in the furnace is insufficient, the above effect cannot be obtained. The oxygen concentration can be up to 100% by volume (pure oxygen atmosphere), but about 30% by volume is sufficient from the viewpoint of cost.
　脱バインダ時における加熱温度は２００℃～８００℃とし、加熱時間は３０時間以上とすることが好ましい。加熱温度が２００℃未満ではバインダが揮発せずに残ってしまい、焼結体密度の低下につながる。一方、８００℃を超えると、脱バインダ工程中に成形体の収縮が始まるため、バインダが焼結体内部に残り、密度低下という問題が生じる。また、加熱時間が３０時間未満では、バインダが十分に分解されない可能性がある。なお、加熱時における成形体の割れを防止する観点から、昇温速度は０．１℃／分～１．５℃／分とすることが好ましく、０．３℃／分～１．０℃／分とすることがより好ましい。 The heating temperature during binder removal is preferably 200 ° C. to 800 ° C., and the heating time is preferably 30 hours or more. When the heating temperature is less than 200 ° C., the binder remains without volatilization, leading to a decrease in the density of the sintered body. On the other hand, when the temperature exceeds 800 ° C., shrinkage of the molded body starts during the binder removal step, so that the binder remains inside the sintered body, causing a problem of density reduction. Further, if the heating time is less than 30 hours, the binder may not be sufficiently decomposed. From the viewpoint of preventing cracking of the molded body during heating, the rate of temperature rise is preferably 0.1 ° C./min to 1.5 ° C./min, and 0.3 ° C./min to 1.0 ° C./min. More preferably, minutes.
　（２－６）焼成工程
　脱バインダ工程後、常圧の大気雰囲気下、１４５０℃～１６００℃の温度で、１０時間～２５時間の焼成を行い、成形体を焼結させる。なお、焼成工程は、脱バインダ工程と連続して同じ加熱炉で行うことが好ましい。 (2-6) Firing Step After the binder removal step, the compact is sintered by firing at a temperature of 1450 ° C. to 1600 ° C. for 10 hours to 25 hours under atmospheric pressure. In addition, it is preferable to perform a baking process with the same heating furnace continuously with a binder removal process.
　焼成温度は１４５０℃～１６００℃とすることが好ましく、１４７０℃～１５７０℃とすることがより好ましい。このような温度範囲で焼成を行うことにより、液相焼結が充分に進行して焼結体密度を高くすることができ、さらには酸化インジウムの溶融を防止して、所望の形状の焼結体の作製が行いやすくなる。 The firing temperature is preferably 1450 ° C. to 1600 ° C., more preferably 1470 ° C. to 1570 ° C. By firing in such a temperature range, the liquid phase sintering can proceed sufficiently to increase the density of the sintered body, and further, the indium oxide can be prevented from melting and sintered in a desired shape. The body can be easily manufactured.
　また、上記の焼成温度での保持時間は、１０時間～２５時間とすることが好ましく、１５時間～２０時間とすることがより好ましい。この範囲内であれば、焼結時間の短縮（電力の使用量減）と高い生産性を実現しつつ、高品質な酸化インジウム系酸化物焼結体を得ることができる。 In addition, the holding time at the above baking temperature is preferably 10 hours to 25 hours, and more preferably 15 hours to 20 hours. Within this range, a high-quality indium oxide-based oxide sintered body can be obtained while realizing a reduction in sintering time (reduction in power consumption) and high productivity.
　なお、成形体の割れを防止しつつ、粒成長を均一に行わせる観点から、昇温速度は０．１℃／分～１．５℃／分とすることが好ましく、０．３℃／分～１．０℃／分とすることがより好ましい。さらに、上記焼成温度で所定時間保持した後は、０．２℃／分～１．２℃／分の範囲の冷却速度で室温付近まで冷却することが好ましい。 From the viewpoint of uniformly performing grain growth while preventing cracking of the molded body, the rate of temperature rise is preferably 0.1 ° C./min to 1.5 ° C./min, preferably 0.3 ° C./min. More preferably, it is set to ˜1.0 ° C./min. Further, after holding at the firing temperature for a predetermined time, it is preferable to cool to near room temperature at a cooling rate in the range of 0.2 ° C./min to 1.2 ° C./min.
　（３）透明導電膜の成膜
　本発明の酸化物焼結体をスパッタリングターゲットに用いて成膜を行う際のスパッタリング法については、何ら制限されることなく、公知のいずれの手段をも用いることができるが、量産性の観点から、直流スパッタリング法、特に、直流マグネトロンスパッタリング装置を用いた手段を採ることが好ましい。本発明のスパッタリングターゲットは、相対密度が９８％以上と高いため、直流スパッタリング法を用いても、アーキングやノジュールの発生は抑制される。 (3) Film Formation of Transparent Conductive Film The sputtering method for film formation using the oxide sintered body of the present invention as a sputtering target is not limited at all, and any known means can be used. However, from the viewpoint of mass productivity, it is preferable to adopt a means using a direct current sputtering method, particularly a direct current magnetron sputtering apparatus. Since the relative density of the sputtering target of the present invention is as high as 98% or more, the occurrence of arcing and nodules is suppressed even when the direct current sputtering method is used.
　また、本発明の酸化物焼結体をスパッタリングターゲットとして成膜を行った場合、スパッタリング時の基板温度を１５０℃以下とした場合であっても、高い結晶性を有する膜を得ることができるため、特に、透明プラスチック基板などの樹脂基板に成膜する場合に、高い透過率を得ることができる。 In addition, when film formation is performed using the oxide sintered body of the present invention as a sputtering target, a film having high crystallinity can be obtained even when the substrate temperature during sputtering is 150 ° C. or lower. Particularly, when a film is formed on a resin substrate such as a transparent plastic substrate, a high transmittance can be obtained.
　本発明の酸化物焼結体をスパッタリングターゲットに用いて成膜する際の条件については、基板温度を除き、特に限定されることはなく、通常の条件において成膜することができる。たとえば、直流マグネトロンスパッタリング装置により、スパッタリングを行う場合には、ターゲット－基板間距離：３５ｍｍ～１２０ｍｍ、到達真空度：１×１０-３Ｐａ以下、導入ガス：０％～１０％のＯ2ガスを含むＡｒガス、ガス圧：０．１Ｐａ～１０．０Ｐａ、投入電力：直流０．５５Ｗ／ｃｍ2～５．５０Ｗ／ｃｍ2とする。なお、基板温度は室温から加熱を行わないことにより、１５０℃未満の温度としてもよく、必要に応じて、基板を冷却して、１５０℃未満の所定温度に保持するようにしてもよい。 The conditions for forming the oxide sintered body of the present invention as a sputtering target are not particularly limited except for the substrate temperature, and can be formed under normal conditions. For example, when sputtering is performed using a direct current magnetron sputtering apparatus, a target-substrate distance: 35 mm to 120 mm, ultimate vacuum: 1 × 10 −3 Pa or less, introduced gas: 0% to 10% O 2 gas. Ar gas contained, gas pressure: 0.1 Pa to 10.0 Pa, input power: DC 0.55 W / cm 2 to 5.50 W / cm 2 . The substrate temperature may be lower than 150 ° C. by not heating from room temperature, or the substrate may be cooled and held at a predetermined temperature lower than 150 ° C. as necessary.
　（４）透明導電膜
　このようにして得られる本発明の透明導電膜は、酸化インジウムを主成分とし、酸化スズおよび酸化コバルトを含有する透明導電膜であって、Ｉｎに対するＳｎの原子比：Ｓｎ／Ｉｎが０．０１９～０．１０２であり、かつ、Ｉｎ、ＳｎおよびＣｏの合計に対する各成分の原子比：Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．７７１～０．９６７、Ｓｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１６～０．０９１、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１５～０．１５であり、比抵抗が５×１０-3Ω・ｃｍ以下である。なお、透明導電膜の比抵抗は、１×１０-3Ω・ｃｍ以下であることが好ましい。 (4) Transparent conductive film The transparent conductive film of the present invention thus obtained is a transparent conductive film containing indium oxide as a main component and containing tin oxide and cobalt oxide, and an atomic ratio of Sn to In: Sn / In is 0.019 to 0.102, and the atomic ratio of each component to the sum of In, Sn, and Co: In / (In + Sn + Co) is 0.771 to 0.967, and Sn / (In + Sn + Co) is 0 .016 to 0.091, Co / (In + Sn + Co) is 0.015 to 0.15, and the specific resistance is 5 × 10 −3 Ω · cm or less. The specific resistance of the transparent conductive film is preferably 1 × 10 −3 Ω · cm or less.
　透明導電膜の組成は、成膜条件に依存する場合もあるが、通常は適切な設定により、成膜材料として用いられる酸化物焼結体の組成と同様とすることができる。すなわち、透明導電膜の組成に基づいて、酸化物焼結体の組成を決定することにより、成膜によって、所望の組成の透明導電膜が得られることとなる。 Although the composition of the transparent conductive film may depend on the film formation conditions, it can usually be the same as the composition of the oxide sintered body used as the film formation material by appropriate setting. That is, by determining the composition of the oxide sintered body based on the composition of the transparent conductive film, a transparent conductive film having a desired composition can be obtained by film formation.
　本発明の透明導電膜では、その膜厚が１５ｎｍ～４０ｎｍの場合に、４００ｎｍ～８００ｎｍの可視光を用いて、分光光度計や分光エリプソメトリにより透過率を測定した場合、平均透過率が膜単体で９８％以上となる。 In the transparent conductive film of the present invention, when the film thickness is 15 nm to 40 nm and the transmittance is measured with a spectrophotometer or spectroscopic ellipsometry using visible light of 400 nm to 800 nm, the average transmittance is a single film. Is 98% or more.
　また、基板を無加熱で成膜した場合であっても、高い結晶性を有する結晶質の透明導電膜となる。これについては、Ｘ線回折を用いた測定において、（２２２）面の回折ピークが強く測定されるか否かにより、確認することができる。この面の回折ピークが強く測定される場合、本発明の透明導電膜は、（２２２）面に主配向しており、結晶性が非常に高い膜となっているといえる。 Further, even when the substrate is formed without heating, it becomes a crystalline transparent conductive film having high crystallinity. This can be confirmed by whether or not the diffraction peak of the (222) plane is strongly measured in the measurement using X-ray diffraction. When the diffraction peak of this surface is strongly measured, it can be said that the transparent conductive film of the present invention is mainly oriented in the (222) plane and has a very high crystallinity.
　さらには、この透明導電膜は、温度９５℃、湿度９５％の環境下に１０００時間さらした場合であっても、その抵抗変化率が１．２以内、好ましくは１．０以下となる。このような特性は、この透明導電膜が適用された製品を高温環境下の屋外で使用する場合や、車載用の電子機器など適用する場合に、特に有効なものである。 Furthermore, even when this transparent conductive film is exposed to an environment at a temperature of 95 ° C. and a humidity of 95% for 1000 hours, the resistance change rate is within 1.2, preferably 1.0 or less. Such characteristics are particularly effective when a product to which the transparent conductive film is applied is used outdoors in a high temperature environment, or when an in-vehicle electronic device is applied.
　（実施例１）
　原料粉末として、酸化インジウム（Ｉｎ2Ｏ3）粉末（純度９９．９％、平均粒径約０．９μｍ）、酸化スズ（ＳｎＯ2）粉末（純度９９．９％、平均粒径約０．９μｍ）、および酸化コバルト（ＣｏＯ）粉末（純度９９．９％、平均粒径約０．８μｍ）の３種類の原料粉末を用意した。 Example 1
As raw material powders, indium oxide (In 2 O 3 ) powder (purity 99.9%, average particle size of about 0.9 μm), tin oxide (SnO 2 ) powder (purity 99.9%, average particle size of about 0.9 μm) ), And cobalt oxide (CoO) powder (purity 99.9%, average particle size of about 0.8 μm).
　これらの原料粉末を、それぞれの含有量が以下の原子比となるように調整した上で、樹脂製ポットに入れた。 These raw material powders were adjusted so that the respective contents had the following atomic ratios, and then placed in a resin pot.
　　Ｓｎ／Ｉｎ＝０．０１９
　　Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）＝０．９６７
　　Ｓｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）＝０．０１８
　　Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）＝０．０１５
　さらに、水溶性バインダとしてポリビニルアルコールを、前記原料粉末の総量に対して１．４質量％となるように秤量し、純水とともに樹脂製ポットに入れ、ボールミル（５ｍｍφのＺｒＯ2ボールを使用）により２４時間粉砕および混合を行い、スラリーを得た。その後、スプレードライヤ（大川原化工機株式会社製、ＯＤＬ－２０型）により、噴霧乾燥を行うことにより、平均粒径が５０μｍの造粒粉を得た。得られた造粒粉をφ１５０ｍｍ寸法の型へ充填し、冷間静水圧プレスで最高圧力を２９４ＭＰａ（３ｔｏｎ／ｃｍ2）として成形体を得た。 Sn / In = 0.019
In / (In + Sn + Co) = 0.967
Sn / (In + Sn + Co) = 0.018
Co / (In + Sn + Co) = 0.015
Furthermore, polyvinyl alcohol as a water-soluble binder is weighed so as to be 1.4% by mass with respect to the total amount of the raw material powder, put into a resin pot together with pure water, and ball mill (using 5 mmφ ZrO 2 balls). The slurry was obtained by grinding and mixing for 24 hours. Thereafter, spray drying was performed with a spray dryer (Ogawara Koki Co., Ltd., ODL-20 type) to obtain a granulated powder having an average particle size of 50 μm. The obtained granulated powder was filled into a mold having a size of φ150 mm, and a compact was obtained with a cold isostatic press at a maximum pressure of 294 MPa (3 ton / cm 2 ).
　さらに、この成形体を焼結炉（丸祥電器株式会社製）内に設置し、炉内容積１ｍ3当たり１００Ｌ／分の割合で酸素を流通させることにより、酸素濃度を３０％以上に維持した状態で７００℃まで加熱し、脱バインダ処理を３４時間行った。その後、炉内雰囲気を大気雰囲気として、最高温度を１５５０℃として２０時間の焼成を行い、焼結体を得た。 Furthermore, this compact was placed in a sintering furnace (manufactured by Marusho Denki Co., Ltd.), and oxygen was circulated at a rate of 100 L / min per 1 m 3 of the furnace volume, thereby maintaining the oxygen concentration at 30% or more. The state was heated to 700 ° C., and the binder removal treatment was performed for 34 hours. Thereafter, firing was performed for 20 hours by setting the atmosphere in the furnace to an air atmosphere and a maximum temperature of 1550 ° C. to obtain a sintered body.
　上記焼結体を研削加工し、直径４インチ（１０１．６ｍｍ）、厚み５ｍｍサイズの酸化インジウム系スパッタリングターゲットを作製した。なお、得られたスパッタリングターゲットをＩＣＰ発光分光測定装置（株式会社島津製作所製、ＩＣＰＳ８１００）で組成分析を行ったところ、原料粉末の組成比と同一であることが確認された。実施例１の原料粉末の組成範囲および焼結温度について、表１に示す。 The above sintered body was ground to produce an indium oxide sputtering target having a diameter of 4 inches (101.6 mm) and a thickness of 5 mm. In addition, when the obtained sputtering target was subjected to composition analysis with an ICP emission spectrometer (ICPS8100, manufactured by Shimadzu Corporation), it was confirmed that it was the same as the composition ratio of the raw material powder. The composition range and sintering temperature of the raw material powder of Example 1 are shown in Table 1.
　得られた酸化インジウム系スパッタリングターゲットについて、相対密度および焼結体の比抵抗について測定をした。 The relative density and specific resistance of the sintered body were measured for the obtained indium oxide-based sputtering target.
　［相対密度］
　スパッタリングターゲットを一定の大きさに切り出した試料について、アルキメデス法により密度の測定を行った。次に、各原料の密度を酸化インジウム：７．１４ｇ／ｃｍ3、酸化スズ：６．９５ｇ／ｃｍ3、酸化コバルト：６．１ｇ／ｃｍ3として加重平均密度（理論密度）を算出し、この加重平均密度を１００％として、相対密度を算出した。この結果、実施例１のスパッタリングターゲットの相対密度は、９８．８％であった。 [Relative density]
About the sample which cut out the sputtering target into the fixed magnitude | size, the density was measured by the Archimedes method. Next, indium oxide density of each raw material: 7.14 g / cm 3, tin oxide: 6.95 g / cm 3, cobalt oxide: calculated weighted mean density (theoretical density) as 6.1 g / cm 3, this The relative density was calculated with the weighted average density as 100%. As a result, the relative density of the sputtering target of Example 1 was 98.8%.
　［焼結体の比抵抗］
　酸化物焼結体の比抵抗は、四探針法抵抗率計ロレスタＥＰ（ダイアインスツルメンツ社製、ＭＣＰ－Ｔ３６０型）を用いて測定した。この結果、実施例１のスパッタリングターゲットの比抵抗は、４．０×１０-3Ω・ｃｍであった。 [Specific resistance of sintered body]
The specific resistance of the oxide sintered body was measured using a four-point probe resistivity meter Loresta EP (Dia Instruments, MCP-T360 type). As a result, the specific resistance of the sputtering target of Example 1 was 4.0 × 10 −3 Ω · cm.
　得られたスパッタリングターゲットを無酸素銅製のバッキングプレートにメタルボンディングして、直流電源を用いたマグネトロンスパッタリング装置（株式会社トッキ製）にセットし、下記の条件でスパッタリングを行い、膜厚２５ｎｍの透明導電膜を得た。基板についてはガラス基板を使用し、基板加熱は行わずに成膜した。 The obtained sputtering target was metal-bonded to an oxygen-free copper backing plate, set in a magnetron sputtering apparatus (made by Tokki Co., Ltd.) using a DC power source, sputtered under the following conditions, and a transparent conductive film having a film thickness of 25 nm. A membrane was obtained. As the substrate, a glass substrate was used, and the film was formed without heating the substrate.
　（スパッタリング条件）
　　基板間距離：６０ｍｍ
　　到達真空度：６×１０-4Ｐａ
　　基板温度　：室温（加熱なし）
　得られた透明導電膜の組成をＩＣＰ発光分光測定装置により確認したところ、スパッタリングターゲットの組成比と同一であった。この透明導電膜について、結晶性、透過率、比抵抗および抵抗変化を測定した。 (Sputtering conditions)
Distance between substrates: 60mm
Ultimate vacuum: 6 × 10 −4 Pa
Substrate temperature: Room temperature (no heating)
When the composition of the obtained transparent conductive film was confirmed with an ICP emission spectrometer, it was the same as the composition ratio of the sputtering target. About this transparent conductive film, crystallinity, transmittance, specific resistance, and resistance change were measured.
　［透明導電膜の結晶性］
　多目的Ｘ線回折装置（スペクトリス株式会社製、Ｘ’Ｐｅｒｔ－ＰＲＯ　ＭＰＤ）を用いて、得られた透明導電酸化物膜の結晶性の確認を行った。（２２２）面の回折ピークが観測された場合は結晶性の膜が得られているものとし、回折ピークが観察されなかった場合は膜が結晶化していないと判定した。この結果、実施例１の透明導電膜は、高い結晶性を有していることが確認された。 [Crystallinity of transparent conductive film]
The crystallinity of the obtained transparent conductive oxide film was confirmed using a multipurpose X-ray diffractometer (Spectres, Inc., X'Pert-PRO MPD). When a diffraction peak on the (222) plane was observed, a crystalline film was obtained, and when no diffraction peak was observed, it was determined that the film was not crystallized. As a result, it was confirmed that the transparent conductive film of Example 1 had high crystallinity.
　［透明導電膜の透過率］
　得られた透明導電酸化物膜について、分光光度計（日本分光株式会社製、ＵｂｅｓｔＶ－５７０ｉＲＭ／ＤＳ）を用いて、波長４００ｎｍ～８００ｎｍの光の透過率を測定した。波長５００ｎｍ～６００ｎｍに透過率のピークが観察された。波長４００ｎｍ～８００ｎｍの透過率の平均値は９８．２％であった。 [Transmissivity of transparent conductive film]
With respect to the obtained transparent conductive oxide film, the transmittance of light having a wavelength of 400 nm to 800 nm was measured using a spectrophotometer (manufactured by JASCO Corporation, UbestV-570iRM / DS). A transmittance peak was observed at a wavelength of 500 nm to 600 nm. The average transmittance at wavelengths of 400 nm to 800 nm was 98.2%.
　［透明導電膜の比抵抗、抵抗変化率］
　透明導電膜の比抵抗は、四探針法抵抗率計ロレスタＥＰ（ダイアインスツルメンツ社製、ＭＣＰ－Ｔ３６０型）で測定した表面抵抗と膜厚の積から算出した。透明導電膜の膜厚は接触式表面粗さ計（テンコール社製）を用いて未成膜部分と成膜部分の段差測定から求めた。 [Specific Resistance of Transparent Conductive Film, Rate of Resistance Change]
The specific resistance of the transparent conductive film was calculated from the product of the surface resistance and the film thickness measured with a four-probe resistivity meter Loresta EP (manufactured by Dia Instruments, MCP-T360 type). The film thickness of the transparent conductive film was determined by measuring the level difference between the non-deposited portion and the deposited portion using a contact-type surface roughness meter (manufactured by Tencor).
　さらに、透明導電膜を温度が９５℃、湿度が９５％の環境に、１０００時間さらす試験を行い、試験前の表面抵抗Ｒ0に対する試験後の表面抵抗Ｒから、Ｒ／Ｒ0として抵抗変化率を求めた。この結果、実施例１の比抵抗は３．０×１０-3Ω・ｃｍ、抵抗変化率は１．２０であった。 Furthermore, the temperature 95 ° C. The transparent conductive film, the humidity is 95% environment were tested exposure 1000 hours, the surface resistance R after the test with respect to the surface resistance R 0 before the test, resistance change rate as R / R 0 Asked. As a result, the specific resistance of Example 1 was 3.0 × 10 −3 Ω · cm, and the resistance change rate was 1.20.
　実施例１のスパッタリングターゲットの相対密度および比抵抗、透明導電膜の結晶性、透過率、比抵抗および抵抗変化率について測定を行った結果を、表２に示す。 Table 2 shows the measurement results of the relative density and specific resistance of the sputtering target of Example 1, the crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
　（実施例２～８）
　各成分の組成比を変更し、表１に記載した値としたこと以外は、実施例１と同様にして、スパッタリングターゲットを得た。これらのスパッタリングターゲットについて、ＩＣＰ発光分光法で組成分析を行ったところ、実施例１と同様に、いずれも原料粉末の組成比と同一であることが確認された。また、これらのスパッタリングターゲットを用いて成膜した透明導電膜についてもＩＣＰ発光分光測定装置で組成分析を行ったところ、実施例１と同様に、いずれもスパッタリングターゲットの組成比と同一であることが確認された。 (Examples 2 to 8)
A sputtering target was obtained in the same manner as in Example 1 except that the composition ratio of each component was changed to the values described in Table 1. About these sputtering targets, when the composition analysis was conducted by ICP emission spectroscopy, it was confirmed that all were the same as the composition ratio of the raw material powder as in Example 1. Moreover, when the composition analysis was conducted on the transparent conductive film formed using these sputtering targets using an ICP emission spectrophotometer, it was found that all of them were the same as the composition ratio of the sputtering target as in Example 1. confirmed.
　実施例２～８のスパッタリングターゲットの相対密度および比抵抗、透明導電膜の結晶性、透過率、比抵抗および抵抗変化率について測定を行った結果を、表２に示す。 Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Examples 2 to 8, crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
　（比較例１、２）
　各成分の組成比を変更し、表１に記載した値としたこと以外は、実施例１と同様にして、スパッタリングターゲットを得た。比較例１は、Ｓｎ／ＩｎとＳｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が本発明の範囲を下回り、Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が本発明の範囲を上回る例である。比較例２は、Ｓｎ／ＩｎとＳｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が本発明の範囲を下回る例である。 (Comparative Examples 1 and 2)
A sputtering target was obtained in the same manner as in Example 1 except that the composition ratio of each component was changed to the values described in Table 1. In Comparative Example 1, Sn / In and Sn / (In + Sn + Co) are below the range of the present invention, and In / (In + Sn + Co) is above the range of the present invention. Comparative Example 2 is an example in which Sn / In and Sn / (In + Sn + Co) are below the range of the present invention.
　これらのスパッタリングターゲットおよび透明導電膜についても、いずれも原料粉末の組成比と同一であることが確認された。比較例１および２のスパッタリングターゲットの相対密度および比抵抗、透明導電膜の結晶性、透過率、比抵抗および抵抗変化率について測定を行った結果を、表２に示す。 These sputtering targets and transparent conductive film were all confirmed to have the same composition ratio as the raw material powder. Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Comparative Examples 1 and 2 and the crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
　（比較例３～５）
　各成分の組成比を変更し、表１に記載した値としたこと以外は、実施例１と同様にして酸化物焼結体を得た。比較例３は、Ｓｎ／ＩｎとＳｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）がともに本発明の範囲を上回る例である。比較例４は、Ｓｎ／Ｉｎが本発明の範囲を上回り、Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が本発明の範囲を下回る例である。比較例５は、Ｓｎ／Ｉｎのみが本発明の範囲を上回る例である。 (Comparative Examples 3 to 5)
An oxide sintered body was obtained in the same manner as in Example 1 except that the composition ratio of each component was changed to the values described in Table 1. Comparative Example 3 is an example in which Sn / In and Sn / (In + Sn + Co) both exceed the scope of the present invention. Comparative Example 4 is an example in which Sn / In exceeds the range of the present invention and In / (In + Sn + Co) falls below the range of the present invention. Comparative Example 5 is an example in which only Sn / In exceeds the scope of the present invention.
　これらのスパッタリングターゲットおよび透明導電膜についても、いずれも原料粉末の組成比と同一であることが確認された。比較例３～５のスパッタリングターゲットの相対密度および比抵抗、透明導電膜の結晶性、透過率、比抵抗および抵抗変化率について測定を行った結果を、表２に示す。 These sputtering targets and transparent conductive film were all confirmed to have the same composition ratio as the raw material powder. Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Comparative Examples 3 to 5, crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
　（比較例６）
　焼成温度を１４００℃にした以外は、実施例４と同様にして酸化物焼結体を得た。これらのスパッタリングターゲットおよび透明導電膜についても、いずれも原料粉末の組成比と同一であることが確認された。比較例６のスパッタリングターゲットの相対密度および比抵抗、透明導電膜の結晶性、透過率、比抵抗および抵抗変化率について測定を行った結果を、表２に示す。 (Comparative Example 6)
An oxide sintered body was obtained in the same manner as in Example 4 except that the firing temperature was 1400 ° C. All of these sputtering targets and transparent conductive films were also confirmed to have the same composition ratio as the raw material powder. Table 2 shows the measurement results of the relative density and specific resistance of the sputtering target of Comparative Example 6, the crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
　（比較例７、８）
　各成分の組成比を変更し、表１に記載した値としたこと以外は、実施例１と同様にして酸化物焼結体を得た。比較例７は、Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が本発明の範囲を上回り、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が本発明の範囲を下回る例である。比較例８は、Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が本発明の範囲を下回り、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が本発明の範囲を上回る例である。 (Comparative Examples 7 and 8)
An oxide sintered body was obtained in the same manner as in Example 1 except that the composition ratio of each component was changed to the values described in Table 1. In Comparative Example 7, In / (In + Sn + Co) exceeds the range of the present invention, and Co / (In + Sn + Co) falls below the range of the present invention. In Comparative Example 8, In / (In + Sn + Co) falls below the range of the present invention, and Co / (In + Sn + Co) exceeds the range of the present invention.
　これらのスパッタリングターゲットおよび透明導電膜についても、いずれも原料粉末の組成比と同一であることが確認された。比較例７および８のスパッタリングターゲットの相対密度および比抵抗、透明導電膜の結晶性、透過率、比抵抗および抵抗変化率について測定を行った結果を、表２に示す。 These sputtering targets and transparent conductive film were all confirmed to have the same composition ratio as the raw material powder. Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Comparative Examples 7 and 8, crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
　（比較例９～１４）
　比較例９～１４では、平均粒径が１．０μｍ以上の原料粉末を１種以上用いたこと以外は、それぞれ実施例１～６と同様にして、酸化物焼結体を得た。これらのスパッタリングターゲットおよび透明導電膜についても、いずれも原料粉末の組成比と同一であることが確認された。比較例９～１４のスパッタリングターゲットの相対密度および比抵抗、透明導電膜の結晶性、透過率、比抵抗および抵抗変化率について測定を行った結果を、表２に示す。 (Comparative Examples 9 to 14)
In Comparative Examples 9 to 14, oxide sintered bodies were obtained in the same manner as in Examples 1 to 6, respectively, except that at least one raw material powder having an average particle size of 1.0 μm or more was used. All of these sputtering targets and transparent conductive films were also confirmed to have the same composition ratio as the raw material powder. Table 2 shows the measurement results of the relative density and specific resistance of the sputtering targets of Comparative Examples 9 to 14, crystallinity, transmittance, specific resistance, and resistance change rate of the transparent conductive film.
　（評価）
　実施例１～８のスパッタリングターゲットは、いずれも９８％以上の相対密度が得られていた。また、実施例１～８のスパッタリングターゲットを用いて得られた透明導電膜は、その比抵抗が５×１０-3Ω・ｃｍ以下となり、タッチパネル等に好適な導電性を示していた。また、透過率についても、それぞれ９８％以上と高い値を示した。なお、実施例１～８のスパッタリングターゲットを用いて成膜する際に、アーキングやノジュールの発生は、ほとんどみられなかった。 (Evaluation)
In all of the sputtering targets of Examples 1 to 8, a relative density of 98% or more was obtained. In addition, the transparent conductive films obtained using the sputtering targets of Examples 1 to 8 had a specific resistance of 5 × 10 −3 Ω · cm or less, and exhibited conductivity suitable for touch panels and the like. Also, the transmittance was as high as 98% or more. In addition, when the film was formed using the sputtering targets of Examples 1 to 8, almost no arcing or nodules were observed.
　これに対して、Ｓｎの含有量が少ない比較例１および２のスパッタリングターゲットは、その相対密度が９８％以上とならず、比抵抗も５×１０-3Ω・ｃｍを超えており、これらを用いて得られた透明導電膜は、透過率、比抵抗および抵抗変化率のいずれも不十分なものであった。 On the other hand, the sputtering target of Comparative Examples 1 and 2 with a small Sn content does not have a relative density of 98% or more, and the specific resistance exceeds 5 × 10 −3 Ω · cm. The transparent conductive film obtained by using the film had insufficient transmittance, specific resistance, and resistance change rate.
　一方、Ｓｎの含有量が多い比較例３～５では、透明導電膜は結晶性が悪く、酸化コバルトの添加による結晶化促進の効果が薄れることが理解された。 On the other hand, in Comparative Examples 3 to 5 having a high Sn content, it was understood that the transparent conductive film had poor crystallinity and the effect of promoting crystallization by adding cobalt oxide was reduced.
　焼結温度が本発明の範囲から外れていた比較例６では、スパッタリングターゲットの相対密度が９８％以上とならず、比抵抗も５×１０-3Ω・ｃｍを超えており、これらを用いて得られた透明導電膜は、比抵抗および抵抗変化率のいずれも不十分なものであった。 In Comparative Example 6 in which the sintering temperature was out of the scope of the present invention, the relative density of the sputtering target did not exceed 98%, and the specific resistance exceeded 5 × 10 −3 Ω · cm. The obtained transparent conductive film was insufficient in both specific resistance and resistance change rate.
　比較例７および８のように酸化コバルトの含有量が、本発明の範囲外の場合には、抵抗変化率が大きくなった。特に、酸化コバルトの含有量が多い比較例８では、結晶性の悪化も確認された。 When the content of cobalt oxide was outside the range of the present invention as in Comparative Examples 7 and 8, the rate of change in resistance increased. In particular, in Comparative Example 8 in which the content of cobalt oxide is large, deterioration of crystallinity was also confirmed.
　平均粒径が１μｍ以上の原料粉末を１種以上用いた比較例９～１４では、スパッタリングターゲットの相対密度が９８％以上とならず、スパッタリングターゲットおよび透明導電膜のいずれも比抵抗が５×１０-3Ω・ｃｍを上回ってしまった。 In Comparative Examples 9 to 14 using one or more raw material powders having an average particle diameter of 1 μm or more, the relative density of the sputtering target does not become 98% or more, and both the sputtering target and the transparent conductive film have a specific resistance of 5 × 10. It exceeded -3 Ω · cm.
　また、これらの比較例のうち、スパッタリングターゲットの相対密が９８％未満である比較例１、２、６、７および９～１４については、実施例１～９と比べて、成膜時にアーキングやノジュールの発生が多く見られ、膜特性の悪化や生産効率の低下が確認された。 Among these comparative examples, Comparative Examples 1, 2, 6, 7, and 9 to 14 in which the relative density of the sputtering target is less than 98% are compared with those in Examples 1 to 9 during arcing and Many nodules were observed, confirming deterioration of film properties and reduction of production efficiency.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　本発明の酸化物焼結体は、太陽電池用透明導電膜、タッチパネル用透明導電膜、フラットパネルディスプレイなどの液晶表示装置用透明導電膜、有機ＥＬ透明導電膜などの高い透過率を必要とする用途に加え、近年、透明プラスチックフィルム基板が必要とされているフィルムタッチパネル用途での透明導電膜を、直流スパッタリング法により得るためのスパッタリングターゲットとして好適である。 The oxide sintered body of the present invention requires high transmittance such as a transparent conductive film for solar cells, a transparent conductive film for touch panels, a transparent conductive film for liquid crystal display devices such as a flat panel display, and an organic EL transparent conductive film. In addition to applications, in recent years, it is suitable as a sputtering target for obtaining a transparent conductive film in a film touch panel application for which a transparent plastic film substrate is required by a direct current sputtering method.

Claims (7)

  1. 　酸化インジウムを主成分とし、酸化スズおよび酸化コバルトを含有する酸化物焼結体であって、Ｉｎに対するＳｎの原子比：Ｓｎ／Ｉｎが０．０１９～０．１０２であり、かつ、Ｉｎ、ＳｎおよびＣｏの合計に対する各成分の原子比：Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．７７１～０．９６７、Ｓｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１６～０．０９１、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１５～０．１５であり、相対密度が９８％以上である、酸化物焼結体。 An oxide sintered body containing indium oxide as a main component and containing tin oxide and cobalt oxide, the atomic ratio of Sn to In: Sn / In being 0.019 to 0.102, and In, Sn And atomic ratio of each component with respect to the sum of Co: 0.771 to 0.967 for In / (In + Sn + Co), 0.016 to 0.091 for Sn / (In + Sn + Co), 0.015 to 0 for Co / (In + Sn + Co) .15 and an oxide sintered body having a relative density of 98% or more.
  2. 　比抵抗が５×１０-3Ω・ｃｍ以下である、請求項１に記載の酸化物焼結体。 The oxide sintered body according to claim 1, wherein the specific resistance is 5 × 10 −3 Ω · cm or less.
  3. 　直流スパッタリング法におけるスパッタリングターゲットとして用いた場合に、基板温度１５０℃以下で成膜を行った場合でも、アーキングを発生させることなく、酸化物透明導電膜の成膜を可能とする、請求項１に記載の酸化物焼結体。 The oxide transparent conductive film can be formed without causing arcing even when the film is formed at a substrate temperature of 150 ° C. or lower when used as a sputtering target in a direct current sputtering method. The oxide sintered body described.
  4. 　平均粒径がいずれも０．０５μｍ以上１．０μｍ未満である酸化インジウム粉、酸化スズ粉、酸化コバルト粉を原料粉末として用い、この原料粉末に、水と水溶性バインダを配合し、得られたスラリーを粉砕し、１０時間以上撹拌した後、乾燥、造粒を行い、得られた造粒粉を型に詰め、加圧成形し、得られた成形体を、酸素雰囲気中、１４５０℃～１６００℃で１２時間～２５時間焼結する工程を備える、請求項１に記載の酸化物焼結体の製造方法。 Indium oxide powder, tin oxide powder, and cobalt oxide powder each having an average particle diameter of 0.05 μm or more and less than 1.0 μm were used as raw material powders, and water and a water-soluble binder were blended into the raw material powders. The slurry is pulverized, stirred for 10 hours or more, dried and granulated. The obtained granulated powder is packed in a mold and pressure-molded, and the resulting molded product is placed in an oxygen atmosphere at 1450 ° C. to 1600 ° C. The method for producing an oxide sintered body according to claim 1, comprising a step of sintering at 20 ° C for 12 to 25 hours.
  5. 　酸化インジウムを主成分とし、酸化スズおよび酸化コバルトを含有する透明導電膜であって、Ｉｎに対するＳｎの原子比：Ｓｎ／Ｉｎが０．０１９～０．１０２であり、かつ、Ｉｎ、ＳｎおよびＣｏの合計に対する各成分の原子比：Ｉｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．７７１～０．９６７、Ｓｎ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１６～０．０９１、Ｃｏ／（Ｉｎ＋Ｓｎ＋Ｃｏ）が０．０１５～０．１５であり、比抵抗が５×１０-3Ω・ｃｍ以下である、酸化物透明導電膜。 A transparent conductive film containing indium oxide as a main component and containing tin oxide and cobalt oxide, the atomic ratio of Sn to In: Sn / In being 0.019 to 0.102, and In, Sn and Co The atomic ratio of each component to the total of: In / (In + Sn + Co) is 0.771 to 0.967, Sn / (In + Sn + Co) is 0.016 to 0.091, and Co / (In + Sn + Co) is 0.015 to 0.15. An oxide transparent conductive film having a specific resistance of 5 × 10 −3 Ω · cm or less.
  6. 　膜厚１５ｎｍ～４０ｎｍで、波長４００ｎｍ～８００ｎｍにおける膜単体の平均透過率が９８％以上である、請求項３に記載の酸化物透明導電膜。 The oxide transparent conductive film according to claim 3, wherein the film has a thickness of 15 nm to 40 nm and an average transmittance of the film alone at a wavelength of 400 nm to 800 nm is 98% or more.
  7. 　温度が９５℃、湿度が９５％の環境に、１０００時間さらした前後における抵抗変化率が１．２以内である、請求項３また４に記載の酸化物透明導電膜。
          5. The transparent oxide conductive film according to claim 3, wherein the rate of change in resistance before and after exposure to an environment having a temperature of 95 ° C. and a humidity of 95% for 1000 hours is 1.2 or less.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09161542A (en) * 1995-12-07 1997-06-20 Idemitsu Kosan Co Ltd Transparent conductive laminate and touch panel using the same
JPH10269843A (en) * 1998-04-13 1998-10-09 Tosoh Corp Conductive metal oxide sintered body and its use
JPH11322413A (en) * 1998-02-16 1999-11-24 Japan Energy Corp Light-transmissive film, high resistivity transparent electroconductive film, sputtering target for forming light-transmissive film and production of the electroconductive film

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09161542A (en) * 1995-12-07 1997-06-20 Idemitsu Kosan Co Ltd Transparent conductive laminate and touch panel using the same
JPH11322413A (en) * 1998-02-16 1999-11-24 Japan Energy Corp Light-transmissive film, high resistivity transparent electroconductive film, sputtering target for forming light-transmissive film and production of the electroconductive film
JPH10269843A (en) * 1998-04-13 1998-10-09 Tosoh Corp Conductive metal oxide sintered body and its use

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
EDITED BY JAPAN SOCIETY FOR THE PROMOTION OF SCIENCE: "The 166th Committee on Photonic and Electronic Oxide", TOMEI DODENMAKU NO GIJUTSU, 1ST EDITION, OHMSHA, LTD., 30 March 1999 (1999-03-30), pages 196 - 201 *
JOLANTA STANKIEWICZ: "Magnetic behavior of sputtered Co-doped indium-tin oxide films", PHYSICAL REVIEW B, vol. 75, no. 23, 2007, pages 235308-1 - 235308-6, XP003030958 *

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