KR101264078B1 - Sintered zinc oxide and method of manufacturing the same - Google Patents

Abstract

The present invention provides a method for controlling the particle size of the first doped material and the second doped material such that the particle diameter of the first doped material and the second doped material is 0.1 to 0.5 times the average particle diameter of the zinc oxide powder, the zinc oxide powder, and A mixing step of preparing a mixed solution by mixing the first doped material and the second doped material whose particle size is controlled, a wet milling step of preparing the mixed solution slurry by milling the mixed solution, and drying and powdering the slurry to prepare granulated powder It provides a powder preparation step, and a method for producing a zinc oxide sintered body comprising the step of molding and sintering the slurry powder. According to the method it is possible to minimize the aggregation of the doping material during the zinc oxide sintered body manufacturing process to reduce the nodule and arcing phenomenon during the sputtering due to the doping material, it is possible to reduce the resistivity of the sintered body and the thin film produced.

Description

Sintered zinc oxide and method of manufacturing the same

The present invention relates to a zinc oxide sintered body and a method for manufacturing the same, wherein the zinc oxide sintered body and the doping materials for sputtering targets having a relatively low production cost and excellent electrical conductivity can reduce oxidation and arcing phenomena generated during sputtering. A method for producing a zinc sintered body.

BACKGROUND ART Liquid crystal displays or electroluminescent displays have excellent display performance and low power consumption, and thus are widely used in display devices such as mobile phones or personal computers, word processors, televisions, and the like. And these display apparatuses have the sandwich structure which sandwiched a display element by the transparent electrode in any apparatus.

The transparent electrode, also called a transparent conductive film, has high conductivity and exhibits high transmittance in the visible light region. Tin oxides (SnO ₂ ) containing a small amount of antimony and fluorine as dopants, indium oxide (In ₂ O ₃ ) containing tin as a small amount of impurities, and the like are widely used in the transparent electrode. In particular, an indium oxide film containing tin as a small amount of impurities, that is, an In ₂ O ₃ -SnO ₂ -based film, is known as an indium tin oxide (ITO) film, and has a resistivity of 2 × 10 ^-4 Ω · cm It has been widely used until now because it is not only easy to obtain a low-resistance film to an extent, but also can be etched and has excellent adhesion to a substrate.

As a manufacturing method of these transparent electrodes, the sputtering method, the vapor deposition method, the ion plating method, the method of apply | coating the coating liquid for transparent conductive layer formation, etc. are mainly used, The double sputtering method is used a lot. The sputtering method is a suitable method when it is necessary to control precise film thickness during the film formation of a material having low vapor pressure, and is widely used when the operation is very simple and the film thickness needs to be controlled.

Specifically, the sputtering method generally causes a glow discharge therebetween by using the substrate as the anode under a gas pressure of about 10 pa or less, and the sputtering target of the formed oxide transparent conductive film as the cathode. At this time, an argon plasma is generated and the argon cations in the plasma collide with the sputtering target of the cathode, whereby particles having a pulling force are stacked on the substrate to form a film. The film formation by the sputtering method has a characteristic that a film can be formed very stably from a thin film of several angstroms to a thick film of several tens of micrometers by controlling variables such as time and voltage. Further, the sputtering method is advantageous in that the composition of the target and the composition of the film formed are the same.

As mentioned above, ITO has many advantages as a transparent electrode film through many studies to date, but supply of indium oxide is unstable and very expensive material. In addition, when a substrate such as a polymer is used in the display device, a transparent electrode film must be formed at a low temperature so as not to have a thermal effect on the display device and the substrate. The ITO transparent electrode film formed at a low temperature has a significantly high electrical conductivity and light transmittance. Because of the problem of falling, the development of a more reliable and low-cost alternative material is required.

Among these alternative materials, zinc oxide oxide doped with aluminum is most popular. Zinc oxide oxide generally has semiconducting properties, so that window materials and sound acoustic wave elements of solar cells It is not only applied to many photoelectric devices such as wave devices and varistor devices, but also because zinc oxide has a wide bandgap and high transmittance from ultraviolet to visible region.

However, in the case of the zinc oxide thin film, it is difficult to form a film having the same level of electrical conductivity as that of the ITO film and the selective etching characteristics are poor, and thus the active commercialization stage has not been reached.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a zinc oxide sintered body which can prevent nodules and arcing occurring during sputtering by a doping material during a zinc oxide manufacturing process.

Another object of the present invention is to provide a zinc oxide sintered body manufactured by the above production method and having an electrical conductivity equivalent to that of a conventional indium tin oxide (ITO) thin film.

According to one aspect of the present invention, in order to manufacture a zinc oxide sintered body, first, the first doped material and the second doped so that the particle diameter of the first doped material and the second doped material is 0.1 to 0.5 times the average particle diameter of the zinc oxide powder. Adjust the particle size of the material. The zinc oxide powder and the first doped material and the second doped material whose particle diameters are controlled are mixed to prepare a mixed liquid. The mixed liquid is milled to prepare a mixed liquid slurry. The slurry is dried and powdered to prepare granular powder. A zinc oxide sintered compact can be manufactured by shape | molding and sintering the said granulated powder.

An aluminum source, a gallium source, an indium source, and the like may be used as the first doping material. In particular, it is preferred to include alumina (Al ₂ O ₃ ) as the first dopant.

The zinc oxide sintered body according to one feature of the present invention includes the first doped material and the second doped material. The particle diameter of the first doped material and the second doped material is 0.1 to 0.5 times the average particle diameter of the zinc oxide.

The thin film specific resistance of the zinc oxide sintered body has a range of 2 × 10 ⁻⁴ to 5 × 10 ⁻⁴ Ω · cm, and the aggregated particle diameter of the first doped material and the second doped material is 2 μm or less.

Hereinafter, the present invention will be described in detail.

In order to manufacture the zinc oxide sintered body according to the present invention, the particle diameter of the zinc oxide powder and the doping materials to be introduced should be strictly controlled. Therefore, prior to the full-scale production process of zinc oxide, the step of adjusting the particle diameter of the zinc oxide powder and the doping materials.

Also, as the doping material in the present invention, different first and second doping materials are used.

Particle diameters of the first doped material and the second doped material introduced are adjusted to be 0.1 to 0.5 times the particle diameter of the zinc oxide powder. It is preferable that the said particle diameter ratio is strictly controlled.

The particle size ratio of the first doped material and the second doped material to zinc oxide has a great influence on the degree of solid solution of the doped materials in the zinc oxide sintered body, and furthermore, it plays an important factor in the specific resistance of the zinc oxide sintered body.

The average particle diameter of the zinc oxide powder used is 0.05-1 micrometer, Preferably it is 0.1-0.5 micrometer.

As the first doping material, an aluminum source, a gallium source, an indium source, or the like may be used, and the first doping materials may be used alone or in combination of two or more. In particular, the first doping material preferably includes aluminum oxide (Al ₂ O ₃ ). As the aluminum oxide, aluminum oxide having a high temperature (α) phase and a low temperature phase (γ, θ, κ, δ, χ) can be used, but aluminum oxide having a high temperature phase is particularly preferable.

The aluminum oxide is doped into the zinc oxide so that 0.1 to 3 parts by weight based on 100 parts by weight of zinc oxide.

As the second doping material, a material containing an element such as indium, gallium, boron, tin, titanium, germanium, vanadium, niobium, tantalum or the like is used. For example, oxides of the above elements can be used.

The second doping impurity is doped into the zinc oxide so that 0.05 to 5 parts by weight relative to 100 parts by weight of zinc oxide.

The zinc oxide powder, the first doped material and the second doped material are mixed with a solvent to prepare a liquid mixture.

The zinc oxide powder, the first doped material and the second doped material may be slurried by wet milling, respectively, before they are mixed. Therefore, the zinc oxide powder, the first doped material and the second doped material may be mixed in a slurry state, respectively.

The mixed liquid is milled by a wet milling method, thereby grinding and slurrying. By the wet milling, the mixed liquid becomes a slurry mixed liquid in a slurry state.

Citric acid (CA), a carboxyl group-containing organic acid, polyacrylic acid (PAA), salts thereof, copolymers thereof, and the like may be added to the mixed liquid or the mixed liquid in a slurry state.

The additives are added to improve the grinding performance and the role of dispersant to allow the zinc oxide powder, the first and second doping materials to be stably dispersed in the solvent. The additives may be adsorbed on the surface of particles such as zinc oxide powder to induce uniform dispersion of the zinc oxide powder.

The additive is preferably added in an amount of 0.01 to 20 parts by weight based on 100 parts by weight of the mixed liquid or mixed liquid slurry.

Before the slurry is prepared or when the slurry preparation is completed, a binder resin may be added to the mixed liquid or the mixed liquid slurry.

The binder resin is added to maintain the molding strength of the molded body in the process of molding the slurry after drying the powder, polyvinyl alcohol, polyethylene glycol, etc. may be used as the binder resin.

The binder resin is preferably added in the mixed liquid or mixed liquid slurry so as to be 0.01 to 5 parts by weight based on 100 parts by weight of the mixed liquid or slurry solids.

The prepared slurry is dried and powdered into granular powder, and the granular powder may be manufactured into a zinc oxide sintered body through a step of forming and sintering. Since the molding and sintering steps can be easily performed by those skilled in the art in a suitable process, a detailed description thereof will be omitted.

As described above, the zinc oxide sintered body produced by strictly restricting the particle size distribution has a specific resistance of 2 × 10 ^-4 to 5 × 10 ^-4 Ω · cm. Therefore, it can have the same level of electrical conductivity as ITO.

The zinc oxide sintered body includes a first doped material and a second doped material as described above.

In the sintered body, the first doped material and the second doped material have a particle size of 0.1 to 0.5 times the average particle diameter of the zinc oxide.

On the other hand, the doped materials in the zinc oxide sintered body prepared as described above have a secondary phase having a cohesive particle diameter of 2 μm or less. That is, the zinc oxide sintered body produced by the method according to the present invention can significantly reduce the aggregation phenomenon during the manufacturing process to minimize the aggregate particle size in the final result.

In particular, the zinc oxide sintered body preferably includes aluminum oxide as the first doping material.

Hereinafter, the present invention will be described in more detail with reference to specific embodiments. However, the technical spirit of the present invention is not limited by the following examples.

 Example 1

Α-Al ₂ O ₃ having an average particle diameter of 1 μm to prepare a zinc oxide sintered body And the α-Al ₂ O ₃ 5 wt% of dispersant by weight was added to the distilled water. The α-Al ₂ O ₃ was added to 2wt% of the weight of zinc oxide. Aluminum oxide as the first doping material was pulverized and dispersed in the wet milling method so that the average particle diameter thereof was 0.1 탆. As in the pulverization of α-Al ₂ O ₃ , Ga ₂ O ₃ was pulverized so as to have an average particle diameter of 0.05 μm as the second doping material. In addition, the zinc oxide was mixed with distilled water so that the zinc oxide is 60% of the total weight of the slurry, and 2 parts by weight of a dispersant based on 100 parts by weight of zinc oxide was added thereto. Thereafter, the zinc oxide was pulverized and dispersed to have an average particle diameter of 0.5 mu m. After these three kinds of slurries were made, wet milling was performed once more with stirring to mix and evenly disperse all of them. When three kinds of slurry were uniformly mixed, 1 wt% of PVA and 0.2 wt% of PEG were added as binder resins, and the mixture was further milled to prepare a uniform slurry.

[Example 2]

Spray drying was used as a method for preparing the final slurry prepared in Example 1 to granule powder. Granule powder was prepared by the spray drying method, and shaping | molding was performed in order to obtain the zinc oxide sintered compact. In the molding, first, the granule powder was first molded by a hydraulic press, and cold isostatic molding was performed to increase the sintered density. The formed article was sintered at 1400 ° C. for 2 hours in an oxygen gas atmosphere. As a result, a zinc oxide sintered body was produced.

As described above, according to the present invention, it is possible to minimize the aggregation and the arcing phenomenon by minimizing the aggregation of the doping materials in the production of the zinc oxide sintered body.

In addition, the zinc oxide sintered body according to the present invention has a lower manufacturing cost than the ITO sintered body, and may exhibit an electrical conductivity equivalent to that of ITO.

As described above, the present invention has been described by way of a limited embodiment, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains may make various modifications and variations from this description. Do. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

Claims (17)

Adjusting particle sizes of the first and second doping materials so that particle sizes of the first and second doping materials are 0.1 to 0.5 times the average particle diameter of the zinc oxide powder; A mixing step of preparing a mixed liquid by mixing the zinc oxide powder and the first doped material and the second doped material whose particle diameter is controlled; A slurry step of preparing a mixed liquid slurry by milling the mixed liquid; A powder step of preparing granule powder by drying and powdering the slurry; And Method for producing a zinc oxide sintered body comprising the step of molding and sintering the granulated powder. The method of claim 1, And the first doped material comprises at least one material selected from the group consisting of aluminum source, gallium source and indium source. The method of claim 1, The first doping material is aluminum oxide (Al ₂ O ₃ ) characterized in that the manufacturing method of the zinc oxide sintered body. The method of claim 3, The said aluminum oxide has a high temperature phase (alpha), The manufacturing method of the zinc oxide sintered compact. The method of claim 3, And the aluminum oxide is doped into the zinc oxide so as to be 0.1 to 3 parts by weight based on 100 parts by weight of the zinc oxide. The method of claim 1, The second doping material comprises at least one of materials comprising any one element selected from the group consisting of indium, gallium, boron, tin, titanium, germanium, vanadium, niobium and tantalum Method for producing zinc sintered body. The method of claim 6, The second doping material is a method of producing a zinc oxide sintered body, characterized in that the zinc oxide is doped so that 0.05 to 5 parts by weight relative to 100 parts by weight of zinc oxide. The method of claim 1, The average particle diameter of the zinc oxide is 0.05 to 1 ㎛ production method of the zinc oxide sintered body. The method of claim 1, At least one compound selected from the group consisting of citric acid (CA), carboxyl group-containing organic acid, polyacrylic acid (PAA), salts thereof and copolymers thereof is added in the mixing step or the slurry step. Manufacturing method. 10. The method of claim 9, The compound is a method for producing a zinc oxide sintered body, characterized in that added to 0.01 to 20 parts by weight based on 100 parts by weight of the mixed solution or slurry solids. The method of claim 1, A method of producing a zinc oxide sintered compact, wherein a binder resin is added to the mixed liquid or slurry after the slurry pre-stage step or the slurry step. 12. The method of claim 11, The binder resin is a method for producing a zinc oxide sintered body comprising at least one resin component of polyvinyl alcohol and polyethylene glycol. 12. The method of claim 11, The binder resin is a method for producing a zinc oxide sintered body, characterized in that added to 0.01 to 5 parts by weight based on 100 parts by weight of the mixed solution or slurry solids. A zinc oxide sintered body in which a first doping material and a second doping material are dissolved, The particle diameter of the first doped material and the second doped material is 0.1 to 0.5 times the average particle diameter of the zinc oxide, The thin film specific resistance of a sintered compact is 2 * 10 <^-4> -5 * 10 <^{-4> (} ohm) * cm, The zinc oxide sintered compact characterized by the above-mentioned. The method of claim 14, The first doping material is aluminum oxide, The second doped material is a zinc oxide sintered body, characterized in that at least one or more of the materials comprising any one element selected from the group consisting of indium, gallium, boron, tin, titanium, germanium, vanadium, niobium and tantalum. delete The method of claim 14, A zinc oxide sintered compact, wherein the aggregated particle diameter of the first doped material and the second doped material is 2 μm or less.