JP5381725B2 - Method for producing ZnO vapor deposition material - Google Patents

Description

  The present invention relates to a transparent conductive film used for, for example, a solar cell, a liquid crystal display device, an electroluminescence display device, a transparent electrode of a transparent piezoelectric sensor of a touch panel device, an active matrix driving device constituting the display device, and an antistatic conductive film The present invention relates to a method for producing a ZnO vapor deposition material used for forming a conductive film used in coatings, gas sensors, electromagnetic shielding panels, piezoelectric devices, photoelectric conversion devices, light-emitting devices, thin-film secondary batteries, and the like.

  In recent years, a transparent conductive film is indispensable when manufacturing photoelectric conversion devices such as solar cells. An ITO film (indium oxide film doped with tin) is known as a conventional transparent conductive film. The ITO film has the advantages of excellent transparency and low resistance.

  On the other hand, cost reduction is required for solar cells, liquid crystal display devices, and the like. However, since indium is expensive, when an ITO film is used as a transparent conductive film, the solar cell inevitably becomes expensive. In addition, when manufacturing solar cells or the like, amorphous silicon is deposited on the transparent conductive film by plasma CVD. At that time, if the transparent conductive film is an ITO film, There was also a problem that the ITO film deteriorated by the hydrogen plasma.

  In order to eliminate these points, zinc oxide doped with conductive active elements such as Al, B, Si, Ge, Sc, Y, La, Ce, Pr, Nd, Pm, and Sm can be manufactured at a lower cost. It has been proposed to use a system film as a transparent conductive film for solar cells or the like, and a zinc oxide-based vapor deposition material for forming this zinc oxide-based film by vapor deposition is disclosed (for example, see Patent Document 1).

JP 2008-088544 A (Claim 1, specifications [0005] to [0008])

  As shown in FIG. 7, the ZnO vapor deposition material disclosed in Patent Document 1 is obtained by mixing a ZnO powder 1 and an additive powder 2 for improving conductivity to obtain a raw material mixed powder 3, and from this powder, a compact is formed. After obtaining 5, a sintered body 6 to be a ZnO vapor deposition material is produced. Here, when the mixing of the ZnO powder 1 and the additive powder 2 for improving the conductivity is insufficient, the additive 2 may segregate, and the aggregate 4 of the additive powder exists in a small ratio. To do. In the sintered body 6 produced by using the raw material mixed powder 3 having such a non-uniform distribution of the additive powder, the additive is segregated in the sintered structure. There will be a portion 7 that has been removed. When film formation is performed using the sintered body 6 having a non-uniform composition distribution as a deposition material such as electron beam vapor deposition or plasma vapor deposition, the film composition is not constant, making it difficult to control the composition of the film. There is also a problem that the concentration of the additive element in the film is lowered. Furthermore, if the additive segregates, evaporation becomes unstable and splash occurs. When splash occurs, the film structure becomes non-uniform, and the specific resistance of the film increases accordingly.

  An object of the present invention is to provide a method for producing a ZnO vapor deposition material excellent in composition uniformity by suppressing segregation of rare earth element oxides containing 2 to 17 rare earth elements added to a ZnO raw material powder. It is in. Another object of the present invention is to provide a method for producing a ZnO vapor deposition material from which a ZnO film having a uniform film composition can be obtained.

  According to a first aspect of the present invention, a composite powder is produced from a ZnO powder having a purity of 98% or more and a rare earth element oxide powder having a purity of 98% or more, and the first granulated powder produced from the composite powder is pelletized. And forming the ZnO vapor-deposited material containing 0.2 to 15% by mass of the rare earth element by molding the green body into a shape, a tablet shape or a plate shape, the rare earth element oxide powder Contains 2 to 17 elements selected from the group of rare earth elements, and a composite powder having an average particle size of 0.05 to 2 μm by mechanical alloying treatment in which the ZnO powder and the rare earth element oxide powder are mixed and pulverized. And a step of producing a first granulated powder from the composite powder.

  According to a second aspect of the present invention, a composite powder is produced from a ZnO powder having a purity of 98% or more and a rare earth element oxide powder having a purity of 98% or more, and the second granulated powder produced from the composite powder is pelletized. And forming the ZnO vapor-deposited material containing 0.2 to 15% by mass of the rare earth element by molding the green body into a shape, a tablet shape or a plate shape, the rare earth element oxide powder Contains 2 to 17 elements selected from the group of rare earth elements, and a composite powder having an average particle size of 0.05 to 2 μm by mechanical alloying treatment in which the ZnO powder and the rare earth element oxide powder are mixed and pulverized. A step of obtaining a composite calcined body by calcining the composite powder at 800 to 1200 ° C. in an atmosphere of air, nitrogen gas, reducing gas, inert gas or vacuum, and the composite temporary Dissolve the fired body Characterized in that it comprises a step of preparing a composite calcined powder to, and a step of preparing a second granulated powder by the composite calcined powder.

  A third aspect of the present invention is an invention based on the first or second aspect, wherein two or more and 17 or less elements selected from the group of rare earth elements are Sc, Y, La, Ce, Pr, It is characterized by containing 2 or more types of Nd, Pm or Sm.

  A fourth aspect of the present invention is an invention based on the first or second aspect, wherein the average particle size of the ZnO powder is 0.1 to 10 μm, and the average particle size of the rare earth element oxide powder is 0. 0.05 to 5 μm.

  A fifth aspect of the present invention is a ZnO film formed by a vacuum film formation method using the ZnO vapor deposition material manufactured by the method of the first to fourth aspects as a target material.

  According to the methods of the first to fourth aspects of the present invention, a composite powder having an average particle size of 0.05 to 2 μm is produced by mechanical alloying treatment in which ZnO powder and rare earth element oxide powder are mixed and pulverized. By producing a ZnO sintered body using, a dispersibility of rare earth elements is improved, segregation is suppressed, and a ZnO vapor deposition material which is a ZnO sintered body having excellent composition uniformity is obtained. That is, the composite powder produced according to the present invention has a very good dispersibility of the rare earth element because ZnO and the rare earth element oxide are compounded at the nanometer level. The dispersibility of the rare earth elements in the aggregate is improved. Furthermore, the ZnO sintered body prepared using the composite calcined powder prepared by calcining and pulverizing this composite powder promotes the formation of a pseudo solid solution of ZnO and rare earth element oxide, so that the composition is uniform. A sintered body with improved properties can be obtained. In addition, according to the method of the third aspect of the present invention, by adding 2 or more and 17 or less rare earth elements, more overelectrons contributing to conduction are generated than when adding one element. The conductivity of the ZnO film can be improved over a wide temperature range. Furthermore, by stabilizing the ZnO crystal structure by a combination of additive elements, high visible light transmittance can be obtained, and the film density is improved, so that durability is improved. It is particularly effective to add a combination of an element having a large ionic radius and an element having a small ionic radius among rare earth elements, or adding a highly reactive element such as Sc. When the vapor deposition material according to the fifth aspect of the present invention is used, stable vapor deposition is possible, the film composition is uniform, the film composition change during film formation is small, and the desired conductivity and visible light transmittance ZnO film. Is obtained. This material can be used not only for forming a transparent conductive film but also for forming a conductive film such as a gas sensor, an electromagnetic shielding panel, and a piezoelectric device.

It is a figure which shows each process in 1st and 2nd embodiment of this invention. It is a schematic diagram which shows the microscopic structure of the composite powder in 1st and 2nd embodiment of this invention. It is a schematic diagram which shows the microscopic structure of the 1st granulated powder in the 1st Embodiment of this invention. It is a schematic diagram which shows the microscopic structure of the 2nd granulated powder in the 2nd Embodiment of this invention. It is a schematic diagram which shows the microscopic structure from the 1st granulated powder to a sintered compact in the 1st Embodiment of this invention. It is a schematic diagram which shows the microscopic structure from the 2nd granulated powder to a sintered compact in the 2nd Embodiment of this invention. It is a schematic diagram which shows the microscopic structure from the raw material mixed powder to a ZnO sintered compact in the conventional method.

  Next, an embodiment for carrying out the present invention will be described with reference to the drawings.

A. First Embodiment <Production Process of Composite Powder by Mechanical Alloying Process>
In general, mechanical alloying is called a mechanical mixing method, and is a method in which pulverization and pressure bonding are repeated so that metal powder or ceramic powder is kneaded by the rotational motion of a hard sphere. Examples of the apparatus include a high energy mixing and pulverizing apparatus such as a ball mill, a planetary ball mill, an attritor, and a bead mill. In the case of using metal powder, there are those in which the inside of the apparatus is evacuated to prevent oxidation, those in which hydrogen is filled, and those having a cooling mechanism. By these mixing and pulverizing apparatuses, the mixed powder of metal powder or ceramic powder is finely pulverized to a level of several tens of nanometers. Refinement to this level promotes solid solution formation, compound formation, or amorphization, and can produce alloys and amorphous alloy powders that are thermodynamically impossible with ordinary melting and powder metallurgy methods. . This is thought to be due to the lattice defects introduced by the deformation of strength resulting in the production of metastable materials. Mechanical alloying is well known to be applied to metal powders, but is also applied to nitrides, carbides or oxides. In addition, when a metal powder and a nitride, carbide or oxide powder are mixed, it is also used in a method for producing an alloy powder in which a nitride, carbide or oxide powder is finely dispersed in a metal matrix.

  Next, as a production example of a composite powder by the mechanical alloying process of the present invention, a production process of a composite powder of ZnO powder and rare earth element oxide powder using a planetary ball mill will be described. A planetary ball mill is a device capable of high-energy mixed grinding because a ball mill container rotates on a rotating disk. As shown in FIG. 1, a predetermined amount of ZnO powder 11 having a purity of 98% or more and a rare earth element oxide powder 12 having a purity of 98% or more and containing 2 or more and 17 or less elements selected from a rare earth element group. The composite powder 13 is produced by performing mechanical alloying treatment by filling the planetary ball mill apparatus and operating it. Preferably, a ZnO powder having a purity of 99.9% or more and a rare earth element oxide powder having a purity of 99.9% or more are used.

  The mixing and pulverization can be carried out by both dry and wet methods, but the wet method is preferable because it has advantages such as less powder adhesion to the container wall surface and balls due to powder aggregation. In the case of wet mixing and grinding, ethanol, n-hexane and the like are preferable as a dispersion medium to be used. Moreover, you may add surfactant, a stearic acid, etc. as a grinding | pulverization additive. The atmosphere in the container is air, but it may be filled with nitrogen or an inert gas.

  The blending ratio of the ZnO powder 11 and the rare earth element oxide powder 12 is such that the total mass of ZnO and the rare earth element oxide is 100% by mass, and the ratio is 0.2 to 15% by mass of the rare earth element. If the rare earth element is less than the lower limit, the concentration of the rare earth element necessary for improving the conductivity of the film cannot be secured, and if the upper limit is exceeded, basic performance as a ZnO conductive film cannot be obtained. . A preferable rare earth element content is 3 to 6% by mass. In addition, by controlling the composition of the composite powder 13 produced by mixing and pulverizing the ZnO powder 11 and 2 or more and 17 or less rare earth element oxide powders 12 within the above range, 2 contained in the ZnO vapor deposition material 16. The total content of the rare earth elements of at least 17 species and not more than 17 species can be controlled in the range of 0.2 to 15% by mass.

  The average particle diameter of the raw material ZnO powder 11 is 0.1 to 10 μm, preferably 0.1 to 5 μm. If the amount is less than the lower limit, the powder is agglomerated, and if the upper limit is exceeded, there is a problem that the effect of forming a pseudo solid solution with the rare earth element oxide cannot be obtained sufficiently. Preferably it is 0.2-2 micrometers. The average particle diameter of the rare earth element oxide powder 12 is 0.05 to 5 μm, preferably 0.05 to 2 μm. If the amount is less than the lower limit, the powder is agglomerated, and if the upper limit is exceeded, there is a problem that the effect of forming a pseudo-solid solution cannot be obtained sufficiently. Preferably it is 0.1-1 micrometer, More preferably, it is 0.1-0.5.

  The particle size of the composite powder 13 is controlled by controlling the pot volume, powder input amount, ball amount, ball diameter, disk rotation speed, type of dispersion medium, dispersion medium input amount, operation time, and the like.

In this embodiment, the disk rotation speed is 500 to 1000 rpm. The ball mill container uses a stainless steel cylindrical pot having a volume of 0.2 to 0.5 L. Menor and zirconia containers can also be used. As the ball, a stabilized ZrO ₂ ball having a diameter of 10 to 30 mmφ is used. The smaller the ball diameter, the more finely pulverized, but the amount of contamination due to wear of the ball also increases. A preferable ball diameter is 15 to 20 mmφ. The input amount of the ball is 1/5 to 1/3 of the volume of the ball mill container. When the input raw material is 50 to 100 g, the mixing and grinding time is 0.2 to 1 hour. If it is less than the lower limit value, pulverization is insufficient, and if it exceeds the upper limit value, aggregation due to excessive pulverization and adhesion to the inner wall of the ball or the pot are likely to occur. Preferably it is 0.4 to 0.6 hours.

  The average particle size of the composite powder 13 produced by mixing and grinding under the above conditions is 0.05 to 2 μm. If the amount is less than the lower limit, the powder is agglomerated, and if the upper limit is exceeded, there is a problem that the effect of forming a pseudo solid solution with the rare earth element oxide cannot be obtained sufficiently. Preferably it is 0.1-5 micrometers.

  The average particle size of these powders was determined by laser diffraction / scattering method (microtrack method), using Nikkiso Co., Ltd. (FRA type), using hexametaphosphate Na as a dispersion medium, and measuring time for one second for 30 seconds. Is obtained by averaging the values measured three times.

  When the pulverization proceeds to a level of several tens of nanometers, the spherical ZnO powder 11 and the rare earth element oxide powder 12 are plastically deformed into a flat irregular shape as shown in FIG. Thus, the composite powder 13 having a quasi-lamella structure that does not exhibit such a perfect layer shape is obtained.

<Granulation process of composite powder>
As shown in FIG. 1, the composite powder 13, an organic solvent, and a binder are mixed to prepare a slurry having a concentration of 30 to 75% by mass. A preferable concentration is 40 to 65% by mass. The reason why the concentration of the slurry is limited to 30 to 75% by mass is that when the content exceeds 75% by mass, the slurry is non-aqueous, so there is a problem that stable mixed granulation is difficult. This is because a dense ZnO sintered body having the above cannot be obtained. The average particle size of the composite powder 13 is preferably in the range of 0.05 to 2 μm. When the average particle size of the composite powder is defined within the above range, if the powder is less than the lower limit value, the powder is too fine and agglomerates, so there is a problem that the handling of the powder is worsened. This is because it is difficult to control and a dense pellet cannot be obtained.

It is preferable to use ethanol or propanol as the organic solvent, and polyethylene glycol or polyvinyl butyral is preferable as the binder. It is preferable that the addition amount of a binder is 0.2-5.0 mass%. Further, the wet mixing of the composite powder 13, the binder, and the organic solvent is performed by a wet ball mill or a stirring mill. In the wet ball mill, when ZrO ₂ balls are used, wet mixing is performed for 8 to 24 hours, preferably 20 to 24 hours, using a large number of ZrO ₂ balls having a diameter of 5 to 10 mm. In the stirring mill, wet mixing is performed for 0.5 to 1 hour using a ZrO ₂ ball having a diameter of 1 to 3 mm. Next, the slurry is spray-dried to obtain a first granulated powder 14 (FIG. 3) having an average particle size of 50 to 250 μm, preferably 100 to 200 μm. The spray drying is preferably performed using a spray dryer.

  As shown in FIG. 3, the first granulated powder 14 is composed of a plurality of lamellar structure composite powders 13 formed by plastically deforming and laminating ZnO powder 11 and rare earth element oxide powder 12 into a flat shape. , And combined by a binder.

<Molding process>
As shown in FIG. 1, the first granulated powder 14 is put into a predetermined mold and molded at a predetermined pressure to produce a molded body 15. As the predetermined mold, a uniaxial pressing device or a cold isostatic pressing device (CIP (Cold Isostatic Press) forming device) is used. A tablet machine, a briquette machine, or the like may be used. In uniaxial pressing apparatus, the first granulated powder ^{14 750~2000kg / cm 2 (73.5~196.1MPa)} , uniaxial pressing at a pressure of preferably 1000~1500kg / cm ² (98.1~147.1MPa) In the CIP molding apparatus, the first granulated powder 14 is 1000 to 3000 kg / cm ² (98.0 to 294.2 MPa), preferably 1500 to 2000 kg / cm ² (147.1 to 196.1 MPa). CIP molding with pressure. The reason why the pressure is limited to the above range is to increase the density of the molded body 15 and prevent deformation after sintering, thereby making post-processing unnecessary.

<Sintering process>
As shown in FIG. 1, the molded body 15 is sintered at a predetermined temperature to produce a ZnO sintered body (ZnO vapor deposition material) 16. Sintering is performed in air, inert gas, vacuum or reducing gas atmosphere. A preferable atmosphere is air or a reducing gas atmosphere. Sintering is performed at a sintering temperature of 1000 ° C. or higher. This is because if the sintering temperature is lower than 1000 ° C., sufficient sinterability cannot be obtained. Preferably, it is 2 to 5 hours at 1200 to 1400 ° C. Thereby, a pellet having a relative density of 90% or more is obtained. The above sintering is performed under atmospheric pressure, but when performing pressure sintering such as hot pressing (HP) sintering or hot isostatic pressing (HIP) sintering, an inert gas, It is preferable to carry out in a vacuum or reducing gas atmosphere at a temperature of 1000 ° C. or higher for 1 to 5 hours. Moreover, it is good also as a plate-shaped sintered compact by uniaxial press.

  FIG. 5 is a diagram schematically showing a microscopic structure of the first granulated powder 14, the molded body 15, and the ZnO sintered body 16. As shown in FIG. 5, since the composite powder 13 has a quasi-lamella structure formed by laminating ZnO powder and rare earth element oxide powder in a flat irregular shape, this granulated powder, compact and ZnO sintered body Among them, the rare earth element oxide is uniformly dispersed. Therefore, as shown in FIG. 7, there is no segregated portion of rare earth element oxides as seen in a ZnO sintered body produced using a mixed powder of ZnO powder and rare earth element oxide powder as a raw material. Thus, the ZnO sintered body (ZnO vapor deposition material) 16 excellent in composition uniformity can be obtained.

<Film formation process>
Using the obtained ZnO sintered body (ZnO vapor deposition material) 16 as a vapor deposition source, a ZnO film is formed on the substrate surface by a vacuum film formation method. Examples of the vacuum film forming method for forming the ZnO film include an electron beam evaporation method, a reactive plasma evaporation method, an ion plating method, and a sputtering method.

  When the rare earth additive element is trivalent or tetravalent and is added to the ZnO film, excess carrier electrons are generated with respect to Zn which is divalent, so that high conductivity is obtained. Also, by adding 2 or more and 17 or less rare earth elements, more overelectrons contributing to the conduction can be generated than when adding one element, and the conductivity of the ZnO film over a wide temperature range. Can be improved. It is preferable to add two or more and 17 or less rare earth elements in combination of an element having a large ionic radius and an element having a small ionic radius. This is because a ZnO crystal distorted by the addition of large ions is recovered and matched by adding small ions, and a film having high visible light transmittance, excellent density and excellent durability can be obtained. . Or it is preferable to add including highly reactive elements, such as Sc. This is because a film having a ZnO crystal structure is restored, and a film having high visible light transmittance, excellent denseness, and excellent durability can be obtained.

B. Second Embodiment <Production Step of Composite Powder by Mechanical Alloying Process>
Similarly to the first embodiment, a predetermined amount of ZnO powder 11 having a purity of 98% or more and rare earth element oxide powder 12 having a purity of 98% or more are filled in a planetary ball mill crusher and operated to perform mechanical alloying treatment. To produce the composite powder 13. Preferably, a ZnO powder having a purity of 99.9% or more and a rare earth element oxide powder having a purity of 99.9% or more are used. The details are in accordance with the first embodiment.

<Calcination process of composite powder>
As shown in FIG. 1, the composite powder 13 produced by mechanical alloying is calcined to produce a composite calcined body 17. Calcination is performed in the atmosphere of air, nitrogen gas, reducing gas, inert gas, or vacuum. A preferable atmosphere is air or a reducing gas atmosphere. The calcination temperature is 800 to 1200 ° C. This is because if the calcination temperature is less than 800 ° C., sufficient sinterability cannot be obtained, and if it exceeds 1200 ° C., ZnO evaporates and the composition components change. The preferred calcination time is 2 to 5 hours. As the crucible used for calcination, an alumina-based, magnesia-based, or zirconia-based crucible is used. Preferably magnesia is used. The purpose of calcination is to cause a reaction at the interface between the ZnO particles and the rare earth element oxide particles to form a pseudo solid solution of ZnO and the rare earth element oxide. Thereby, the effect which the dispersibility of the rare earth element with respect to a ZnO matrix improves can be anticipated. In addition, the reactivity can be controlled by the sintering temperature.

<Process of crushing composite calcined body>
As shown in FIG. 1, the composite calcined body 17 obtained by the calcining is mechanically crushed to produce a composite calcined powder 18. As the crusher, a jaw crusher, a roll crusher, a hammer crusher, a disc crusher, a stamp mill, a ball mill, a bead mill, a vibration mill, a jet mill, or the like is used. Preferably, a hammer mark lasher is used. This is because impurities are relatively low and the process is simple. Grind until the average particle size is in the range of 0.05-5 μm, preferably 0.1-5 μm. The reason why the average particle size of the composite calcined powder 18 is controlled within this range is that the powder is agglomerated significantly if it is less than the lower limit, and handling becomes difficult, and if the upper limit is exceeded, the sinterability deteriorates. Especially preferably, it is 0.1-2 micrometers, More preferably, it is 0.2-2 micrometers.

  As shown in FIG. 4, in the composite calcined powder 18, a pseudo solid solution 20 is formed between ZnO and the rare earth element oxide, and the dispersibility of the rare earth element is improved.

<Granulation process of composite calcined powder>
As shown in FIG. 1, a second granulated powder 19 (FIG. 4) is produced from the composite calcined powder 18. The details are based on the granulation step of the composite powder 13 of the first embodiment.

<Molding process>
As shown in FIG. 1, the 2nd granulated powder 19 is shape | molded and the molded object 21 is produced. The details are based on the molding process of the first embodiment.

<Sintering process>
As shown in FIG. 1, the molded body 21 is sintered at a predetermined temperature to produce a ZnO sintered body (ZnO vapor deposition material) 22. Sintering is performed in air, inert gas, vacuum or reducing gas atmosphere. Preferred atmospheres are air, inert gas, vacuum or reducing gas atmosphere. Sintering is performed at a sintering temperature of 1000 ° C. or higher. When the sintering temperature was less than 1000 ° C., sufficient sinterability could not be obtained, so this temperature condition was used. Preferably, it is 2 to 5 hours at 1200 to 1400 ° C. Thereby, a pellet having a relative density of 90% or more is obtained. The above sintering is performed under atmospheric pressure, but when performing pressure sintering such as hot pressing (HP) sintering or hot isostatic pressing (HIP) sintering, an inert gas, It is preferable to carry out in a vacuum or reducing gas atmosphere at a temperature of 1000 ° C. or higher for 1 to 5 hours. Moreover, it is good also as a plate-shaped sintered compact by uniaxial press.

  FIG. 6 is a diagram schematically showing a microscopic structure of the second granulated powder 19, the compact 21, and the ZnO sintered body 22. As shown in FIG. 6, in the composite calcined powder 18, ZnO and rare earth element oxide form a pseudo solid solution 20, and therefore, in this granulated powder, compact and ZnO sintered body, rare earth element oxidation is performed. Things are evenly dispersed. Therefore, as shown in FIG. 7, there is no segregated portion of rare earth element oxides as seen in a ZnO sintered body produced using a mixed powder of ZnO powder and rare earth element oxide powder as a raw material. Thus, the ZnO sintered body (ZnO vapor deposition material) 22 excellent in composition uniformity can be obtained.

<Film formation process>
A ZnO film is produced using the ZnO sintered body (ZnO vapor deposition material) 22 produced according to the second embodiment as an evaporation source. The details are in accordance with the film forming process of the first embodiment.

  Next, examples of the present invention will be described in detail together with comparative examples.

<Example 1>
First, a ZnO powder having an average particle diameter of 2.0 μm and a purity of 99.7%, a CeO ₂ powder having an average particle diameter of 2.5 μm and a purity of 99.5%, and an average particle diameter of 2.5 μm and a purity of 99.5% Sc ₂ O ₃ powder was weighed in a predetermined amount, filled in a planetary ball mill device, and this device was operated to perform a mechanical alloying process for mixing and pulverizing the powder to produce a composite powder. . This mixing and grinding was performed by wet mixing, ethanol was added as a dispersion medium, and a surfactant was added as a grinding additive. The atmosphere in the container was air. The average particle size of the composite powder produced by performing the mechanical alloying treatment was 0.5 μm. Here, regarding the composition of the composite powder, when the total mass of ZnO powder, CeO ₂ powder (rare earth element oxide powder) and Sc ₂ O ₃ powder (rare earth element oxide powder) is 100% by mass, Ce ( The content ratio of rare earth elements) and Sc (rare earth elements) was controlled to be 2 mass%.

Next, an organic solvent and a binder were added to and mixed with the composite powder to prepare a slurry having a concentration of 50% by mass. Ethanol was used as the organic solvent, and polyvinyl butyral was used as the binder. Moreover, the addition amount of the binder was 0.5 mass%. The wet mixing of the composite powder, the organic solvent and the binder was performed by a stirring mill. The slurry was spray-dried using a spray dryer to obtain a first granulated powder having an average particle size of 200 μm. The first granulated powder was uniaxially pressed at a pressure of 1000 kg / cm ² (98 MPa) using a uniaxial press device (manufactured by Riken Seiki Co., Ltd., model name: CD type) to produce a compact. Furthermore, a ZnO vapor deposition material (ZnO sintered body) was obtained by sintering the molded body in an air atmosphere at a temperature of 1200 ° C. for 5 hours using an air firing furnace. This ZnO vapor deposition body was taken as Example 1.

<Example 2>
As shown in Table 1 below, ZnO deposition was performed in the same manner as in Example 1 except that the Ce (rare earth element) content was 5 mass% and the Sc (rare earth element) content was 5 mass%. The body was made. This ZnO vapor deposition body was taken as Example 2.

<Example 3>
As shown in Table 1 below, ZnO deposition was performed in the same manner as in Example 1 except that the Ce (rare earth element) content was 10 mass% and the Nd (rare earth element) content was 5 mass%. The body was made. This ZnO vapor deposition body was taken as Example 3.

<Example 4>
As shown in Table 1 below, ZnO deposition was performed in the same manner as in Example 1 except that the content of Sc (rare earth element) was 1 mass% and the content of Nd (rare earth element) was 1 mass%. The body was made. This ZnO vapor deposition body was taken as Example 4.

<Example 5>
First, in the same manner as in Example 1, a predetermined amount of ZnO powder, Sc ₂ O ₃ powder and Nd ₂ O ₃ powder are weighed, and these powders are filled in a planetary ball mill device, and mechanical alloying treatment is performed. A composite powder having an average particle size of 0.5 μm was prepared. Here, regarding the composition of the composite powder, when the total mass of ZnO powder, Sc ₂ O ₃ powder (rare earth element oxide powder) and Nd ₂ O ₃ powder (rare earth element oxide powder) is 100% by mass, The content ratio of Sc (rare earth element) and Nd (rare earth element) was controlled to be 5 mass% and 3 mass%, respectively. Next, the composite powder was calcined to produce a composite calcined body. The calcination was performed in the air, the calcination temperature was 1000 ° C., and the calcination time was 3 hours. The composite calcined body was mechanically crushed to produce a composite calcined powder. As a crusher, a Hanmark lasher was used, and a composite calcined powder having an average particle size of 0.4 μm was produced using this crusher. Next, in the same manner as in Example 1, an organic solvent and a binder were added to and mixed with the composite calcined powder to prepare a slurry, and this slurry was spray-dried using a spray dryer to obtain an average particle size. A second granulated powder having a diameter of 200 μm was obtained. Further, in the same manner as in Example 1, the second granulated powder was uniaxially pressed using a uniaxial press device to produce a molded product, and this molded product was sintered using an atmospheric firing furnace. A ZnO vapor deposition body was obtained. This ZnO vapor deposition body was taken as Example 5.

<Example 6>
As shown in Table 1 below, ZnO deposition was performed in the same manner as in Example 5 except that the content of Sc (rare earth element) was 5 mass% and the content of La (rare earth element) was 10 mass%. The body was made. This ZnO vapor deposition body was taken as Example 6.

<Example 7>
As shown in Table 1 below, ZnO deposition was performed in the same manner as in Example 5 except that the content of Sc (rare earth element) was 1 mass% and the content of La (rare earth element) was 3 mass%. The body was made. This ZnO vapor deposition body was taken as Example 7.

<Example 8>
As shown in Table 1 below, ZnO deposition was carried out in the same manner as in Example 5 except that the content of Sc (rare earth element) was 3 mass% and the content of Sm (rare earth element) was 5 mass%. The body was made. This ZnO vapor deposition body was determined as Example 8.

<Example 9>
As shown in the following Table 1, the average particle diameter of ZnO powder is 10.0 μm, the content of Sc (rare earth element) is 5 mass%, the content of La (rare earth element) is 2 mass%, A ZnO vapor deposition body was produced in the same manner as in Example 1 except that the average particle size of the composite powder after the alloying treatment was 1 μm. This ZnO vapor deposition body was taken as Example 9.

<Example 10>
As shown in Table 1 below, the content of Y (rare earth element) is 3% by mass, the content of La (rare earth element) is 3% by mass, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor deposition body was produced like Example 1 except having been 1 micrometer. This ZnO vapor deposition body was taken as Example 10.

<Example 11>
As shown in Table 1 below, the average particle size of ZnO powder is 10.0 μm, the content of Y (rare earth element) is 3 mass%, the content of Sm (rare earth element) is 5 mass%, A ZnO vapor deposition body was produced in the same manner as in Example 1 except that the average particle size of the composite powder after the alloying treatment was 1 μm. This ZnO vapor deposition body was taken as Example 11.

<Example 12>
As shown in the following Table 1, the average particle size of ZnO powder is 10.0 μm, the content of Pr (rare earth element) is 1% by mass, the content of Sc (rare earth element) is 2% by mass, A ZnO vapor deposition body was prepared in the same manner as in Example 5 except that the average particle size of the composite powder after the alloying treatment was 1 μm and the average particle size of the composite calcined powder after the pulverization treatment was 0.5 μm. Produced. This ZnO vapor deposition body was taken as Example 12.

<Example 13>
As shown in the following Table 1, the Pr (rare earth element) content is 3 mass%, the La (rare earth element) content is 2 mass%, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor-deposited body was prepared in the same manner as in Example 5 except that the average particle size of the composite calcined powder after pulverization was 1 μm and 0.5 μm. This ZnO vapor deposition body was taken as Example 13.

<Example 14>
As shown in the following Table 1, the average particle size of ZnO powder is 10.0 μm, the content of Nd (rare earth element) is 2 mass%, the content of Y (rare earth element) is 2 mass%, A ZnO vapor deposition body was prepared in the same manner as in Example 5 except that the average particle size of the composite powder after the alloying treatment was 1 μm and the average particle size of the composite calcined powder after the pulverization treatment was 0.5 μm. Produced. This ZnO vapor deposition body was taken as Example 14.

<Example 15>
As shown in Table 1 below, the content of Pm (rare earth element) is 3% by mass, the content of Sm (rare earth element) is 4% by mass, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor-deposited body was prepared in the same manner as in Example 5 except that the average particle size of the composite calcined powder after pulverization was 1 μm and 0.5 μm. This ZnO vapor deposition body was taken as Example 15.

<Example 16>
As shown in the following Table 1, the content of La (rare earth element) is 3% by mass, the content of Nd (rare earth element) is 3% by mass, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor-deposited body was prepared in the same manner as in Example 5 except that the average particle size of the composite calcined powder after pulverization was 1 μm and 0.5 μm. This ZnO vapor deposition body was taken as Example 16.

<Comparative Example 1>
As shown in Table 2 below, the content of Ce (rare earth element) was 2 mass%, the content of Sc (rare earth element) was 2 mass%, and the mechanical alloying treatment was not performed. A ZnO vapor deposition body was produced in the same manner as in Example 1. This ZnO vapor deposition body was designated as Comparative Example 1.

<Comparative example 2>
As shown in the following Table 2, the Ce (rare earth element) content is 5% by mass, the Sc (rare earth element) content is 5% by mass, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor deposition body was produced in the same manner as in Example 1 except that the thickness was 0.02 μm. This ZnO vapor deposition body was set as Comparative Example 2.

<Comparative Example 3>
As shown in Table 2 below, the content of Ce (rare earth element) was 10 mass%, the content of Nd (rare earth element) was 10 mass%, and the mechanical alloying treatment was not performed. A ZnO vapor deposition body was produced in the same manner as in Example 1. This ZnO vapor deposition body was designated as Comparative Example 3.

<Comparative Example 4>
As shown in the following Table 2, except that the content of Sc (rare earth element) is 1% by mass, the content of Nd (rare earth element) is 1% by mass, and mechanical alloying treatment is not performed. A ZnO vapor deposition body was produced in the same manner as in Example 1. This ZnO vapor deposition body was designated as Comparative Example 4.

<Comparative Example 5>
As shown in the following Table 2, the Sc (rare earth element) content is 5 mass%, the Nd (rare earth element) content is 3 mass%, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor-deposited body was prepared in the same manner as in Example 5 except that the average particle size of the composite calcined powder after pulverization was 5 μm. This ZnO vapor deposition body was designated as Comparative Example 5.

<Comparative Example 6>
As shown in Table 2 below, the content of Sc (rare earth element) was 5 mass%, the content of La (rare earth element) was 10 mass%, and the mechanical alloying treatment was not performed. A ZnO vapor deposition body was produced in the same manner as in Example 1. This ZnO vapor deposition body was designated as Comparative Example 6.

<Comparative Example 7>
As shown in the following Table 2, the Sc (rare earth element) content is 1 mass%, the La (rare earth element) content is 3 mass%, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor deposition body was produced in the same manner as in Example 1 except that the thickness was 5 μm. This ZnO vapor deposition body was designated as Comparative Example 7.

<Comparative Example 8>
As shown in the following Table 2, the Sc (rare earth element) content is 3 mass%, the Sm (rare earth element) content is 5 mass%, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor-deposited body was produced in the same manner as in Example 5 except that the average particle size of the composite calcined powder after the pulverization treatment was 8 μm. This ZnO vapor deposition body was designated as Comparative Example 8.

<Comparative Example 9>
As shown in Table 2 below, the average particle size of the ZnO powder is 10.0 μm, the Sc (rare earth element) content is 5 mass%, the La (rare earth element) content is 2 mass%, A ZnO vapor-deposited body was produced in the same manner as in Example 1 except that the average particle size of the composite powder after the alloying treatment was 0.02 μm. This ZnO vapor deposition body was determined as Comparative Example 9.

<Comparative Example 10>
As shown in the following Table 2, the Y (rare earth element) content is 3 mass%, the La (rare earth element) content is 3 mass%, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor-deposited body was prepared in the same manner as in Example 5 except that the average particle size of the composite calcined powder after the pulverization treatment was 7 μm. This ZnO vapor deposition body was designated as Comparative Example 10.

<Comparative Example 11>
As shown in Table 2 below, the average particle diameter of the ZnO powder is 10.0 μm, the content of Y (rare earth element) is 3 mass%, the content of Sm (rare earth element) is 5 mass%, A ZnO vapor deposition body was produced in the same manner as in Example 1 except that the alloying treatment was not performed. This ZnO vapor deposition body was set as Comparative Example 11.

<Comparative Example 12>
As shown in Table 2 below, the average particle size of ZnO powder is 10.0 μm, the content of Pr (rare earth element) is 1% by mass, the content of Sc (rare earth element) is 2% by mass, A ZnO vapor deposition body was produced in the same manner as in Example 1 except that the alloying treatment was not performed. This ZnO vapor deposition body was determined as Comparative Example 12.

<Comparative Example 13>
As shown in Table 2 below, the Pr (rare earth element) content is 3 mass%, the La (rare earth element) content is 2 mass%, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor-deposited body was prepared in the same manner as in Example 5 except that the average particle size of the composite calcined powder after the pulverization treatment was 7 μm. This ZnO vapor deposition body was determined as Comparative Example 13.

<Comparative example 14>
As shown in Table 2 below, the average particle size of ZnO powder is 10.0 μm, the content of Nd (rare earth element) is 2 mass%, the content of Y (rare earth element) is 2 mass%, A ZnO vapor deposition body was produced in the same manner as in Example 1 except that the alloying treatment was not performed. This ZnO vapor deposition body was determined as Comparative Example 14.

<Comparative Example 15>
As shown in the following Table 2, the content of Pm (rare earth element) is 3% by mass, the content of Sm (rare earth element) is 4% by mass, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor deposition body was produced in the same manner as in Example 1 except that the thickness was 7 μm. This ZnO vapor deposition body was determined as Comparative Example 15.

<Comparative Example 16>
As shown in the following Table 2, the content of La (rare earth element) is 3% by mass, the content of Nd (rare earth element) is 3% by mass, and the average particle size of the composite powder after mechanical alloying is A ZnO vapor-deposited body was produced in the same manner as in Example 5 except that the average particle size of the composite calcined powder after pulverization was 0.02 μm. This ZnO vapor deposition body was determined as Comparative Example 16.

<Comparison test and evaluation>
Using the ZnO vapor deposition materials obtained in Examples 1 to 16 and Comparative Examples 1 to 16, a ZnO film having a predetermined thickness was formed on a glass substrate by an electron beam vapor deposition method. The film formation conditions are as follows: the ultimate vacuum is 1.0 × 10 ⁻⁴ Pa, the oxygen gas partial pressure is 1.0 × 10 ⁻² Pa, the substrate temperature is 200 ° C., and the film formation rate is 0.8. It was 5 nm / second. About the formed ZnO film | membrane, the film thickness, the transmittance | permeability, and the specific resistance were evaluated, respectively. These results are shown in Tables 1 and 2 below.

The film thickness was measured with a Dektak 6M type contact film thickness meter manufactured by ULVAC. The transmittance is measured by using a spectrophotometer U-4000 manufactured by Hitachi, Ltd. as a measuring instrument, and placing the substrate after film formation perpendicular to the measurement light in the visible wavelength range of 380 to 780 nm. did. The specific resistance is determined by a 4-terminal 4-probe method by applying a constant current at a so-called normal temperature at 25 ° C. using a Loresta (HP type, MCP-T410, probe in series 1.5 mm pitch) manufactured by Mitsubishi Chemical Corporation. It was measured. The measurable range of the volume resistance is 1.0 × 10 ^{−6 to} 1.0 × 10 ⁸ Ω · cm.

表１及び表２から明らかなように、実施例１、３及び４と比較例１、３及び４を比較すると、メカニカルアロイング処理を行わなかった比較例１、３及び４では、比抵抗が７．６×１０^-4〜８．３×１０^-4Ωｃｍと大きかったのに対し、メカニカルアロイング処理（処理後の複合粉末の平均粒径０．５μｍ（０．０５〜２μｍの範囲内））を行った実施例１、３及び４では、比抵抗が５．３×１０^-4〜６．１×１０^-4Ωｃｍと小さくなった。

As is clear from Tables 1 and 2, when Examples 1, 3 and 4 are compared with Comparative Examples 1, 3 and 4, in Comparative Examples 1, 3 and 4 where mechanical alloying treatment was not performed, the specific resistance was Mechanical alloying treatment (average particle size of composite powder after treatment: 0.5 μm (within a range of 0.05 to 2 μm), whereas 7.6 × 10 ^{−4 to} 8.3 × 10 ⁻⁴ Ωcm was large In Examples 1, 3 and 4 in which the specific resistance was performed, the specific resistance was reduced to 5.3 × 10 ^{−4 to} 6.1 × 10 ⁻⁴ Ωcm.

Comparing Example 2 and Comparative Example 2, in Comparative Example 2 where the average particle size of the composite powder after mechanical alloying was 0.02 μm, the specific resistance was as large as 7.9 × 10 ⁻⁴ Ωcm. On the other hand, in Example 2 where the average particle size of the composite powder after mechanical alloying was 0.5 μm (in the range of 0.05 to 2 μm), the specific resistance was as small as 5.9 × 10 ⁻⁴ Ωcm. became.

When Examples 5-8 are compared with Comparative Examples 5-8, the average particle size of the composite powder after mechanical alloying treatment is large, the average particle size of the composite calcined powder after pulverization treatment is large, mechanical alloying In Comparative Examples 5 to 8 in which the treatment and the composite calcined body were not pulverized, the specific resistance was as large as 8.4 × 10 ^{−4 to} 10.8 × 10 ⁻⁴ Ωcm, whereas mechanical alloying treatment was performed. The average particle size of the subsequent composite powder is 0.5 μm (in the range of 0.05 to 2 μm), and the average particle size of the composite calcined powder after the pulverization is 0.4 μm (in the range of 0.05 to 5 μm). In Examples 5 to 8, the specific resistance was as small as 6.2 × 10 ^{−4 to} 7.2 × 10 ⁻⁴ Ωcm.

When Examples 9 to 11 and Comparative Examples 9 to 11 are compared, the average particle size of the composite powder after mechanical alloying is small, or the average particle size of the composite powder after mechanical alloying and the composite temporary after grinding In Comparative Examples 9 to 11 in which the average particle diameter of the calcined powder was large or the mechanical alloying treatment and the composite calcined body were not pulverized, the specific resistance was 9.6 × 10 ^{−4 to} 10.7 × 10 ^Although the average particle diameter of the composite powder after the mechanical alloying treatment was 1 μm (within a range of 0.05 to 2 μm), the composite calcined body was not manufactured. 11, the specific resistance decreased to 6.8 × 10 ^{−4 to} 7.4 × 10 ⁻⁴ Ωcm.

When Examples 12 to 16 and Comparative Examples 12 to 16 are compared, the type of rare earth element oxide powder is changed, the mechanical alloying process and the composite calcined body are not pulverized, or the composite after the mechanical alloying process is performed. In Comparative Examples 12 to 16 in which the average particle size of the powder and the average particle size of the composite calcined powder after pulverization were large or small, the specific resistance was 9.1 × 10 ^{−4 to} 11.6 × 10 ⁻⁴ Ωcm. On the other hand, the type of rare earth element oxide powder was changed, and the average particle size of the composite powder after mechanical alloying was 1 μm (in the range of 0.05 to 2 μm). In Examples 12 to 16 in which the average particle size of the calcined powder was 0.5 μm (in the range of 0.05 to 5 μm), the specific resistance was 6.8 × 10 ^{−4 to} 7.5 × 10 ⁻⁴ Ωcm. It became small.

DESCRIPTION OF SYMBOLS 11 ZnO powder 12 Rare earth element oxide containing 2 or more and 17 or less elements selected from rare earth element group Powder 13 Composite powder 14 First granulated powder 15 Molded body 16 ZnO sintered body (ZnO vapor deposition material)
17 Composite calcined body 18 Composite calcined powder 19 Second granulated powder 20 Pseudo solid solution of ZnO and rare earth element oxide 21 Molded body 22 ZnO sintered body (ZnO vapor deposition material)

Claims (5)

A composite powder is prepared from a ZnO powder having a purity of 98% or more and a rare earth element oxide powder having a purity of 98% or more, and the first granulated powder prepared from the composite powder is formed into a pellet, tablet or plate. Then, the compact is sintered to produce a ZnO vapor deposition material containing 0.2 to 15% by mass of the rare earth element,
The rare earth oxide powder contains 2 or more and 17 or less elements selected from the group of rare earth elements,
Producing a composite powder having an average particle size of 0.05 to 2 μm by mechanical alloying treatment of mixing and grinding the ZnO powder and the rare earth element oxide powder;
And a step of producing a first granulated powder from the composite powder. A composite powder is produced from a ZnO powder having a purity of 98% or more and a rare earth element oxide powder having a purity of 98% or more, and the second granulated powder produced from the composite powder is formed into a pellet, tablet or plate. Then, the compact is sintered to produce a ZnO vapor deposition material containing 0.2 to 15% by mass of the rare earth element,
The rare earth oxide powder contains 2 or more and 17 or less elements selected from the group of rare earth elements,
Producing a composite powder having an average particle size of 0.05 to 2 μm by mechanical alloying treatment of mixing and grinding the ZnO powder and the rare earth element oxide powder;
A step of obtaining a composite calcined body by calcining the composite powder at 800 to 1200 ° C. in an atmosphere of air, nitrogen gas, reducing gas, inert gas or vacuum;
Crushing the composite calcined body to produce a composite calcined powder;
And a step of producing a second granulated powder by the composite calcined powder.   The method for producing a ZnO vapor deposition material according to claim 1 or 2, wherein two or more and 17 or less elements selected from a rare earth element group contain two or more of Sc, Y, La, Ce, Pr, Nd, Pm, or Sm.   The method for producing a ZnO vapor deposition material according to claim 1 or 2, wherein the ZnO powder has an average particle size of 0.1 to 10 µm and the rare earth element oxide powder has an average particle size of 0.05 to 5 µm.   A ZnO film formed by a vacuum film-forming method using the ZnO vapor deposition material manufactured by the method according to claim 1 as a target material.

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