High work function metal oxide target material and method for manufacturing the same.

Abstract

This invention provides a high work function metal oxide target material and a method for producing the same. [Solution] The manufacturing method includes the steps of: mixing high work function metal oxide powder, indium oxide powder, and zinc oxide powder into a mixed powder in a predetermined mass ratio; putting the mixed powder into deionized water, adding a dispersant, and preparing a slurry; performing high-energy sand mill grinding on the slurry, and adding a binder before the end of sand mill grinding; spray granulation of the slurry to obtain spherical granulated powder; performing mold press molding and cold isostatic pressurization on the spherical granulated powder to obtain a target material blank; and performing degreasing and sintering integration treatment on the target material blank to obtain a high work function metal oxide target material. [Effects] The disclosed target material has a small crystal grain size, uniform distribution, high density, and excellent electrical performance, and can be used in the manufacture of flexible OLED anodic layer thin film materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of sputtering target materials, and specifically relates to a high work function metal oxide target material and a method for manufacturing the same.

Background Art

[0002] Currently, the digitalized society is developing rapidly, and the demand for flat panel displays with high refresh rate, high resolution, and low power consumption is increasing. Among them, Organic Light-Emitting Diode (OLED) has high efficiency and brightness, wide viewing angle, low power consumption, self-emission, low driving voltage, high response speed, full color, can be manufactured in ultra-thin and large area, the material is lightweight, flexible, easy to process, and has high applicability, etc., and can meet the requirements for higher performance and larger information capacity of current display devices.

[0003] In an OLED device, currently, the most common anode thin film material is ITO with a work function (WF) of about -4.7 eV. However, the highest occupied molecular orbital (HOMO) energy level of the organic hole transport layer is usually about -5.7 eV. Since the work function of ITO does not match the HOMO energy level of the organic layer, the hole injection efficiency decreases, and further affects the startup voltage and overall power consumption of the device. To solve this problem, usually, a hole injection layer (HIL) is added between the anode and the organic hole transport layer, and the HOMO energy level of this layer is about -5.2 eV, which can match the energy levels of the anode and the organic layer better, so the hole injection efficiency is improved. However, this method not only increases the manufacturing process of the OLED device but also increases the cost. Therefore, it is necessary to urgently develop a transition metal oxide anode material with high work function, high light transmittance, and conductivity to reduce costs and improve efficiency.

Summary of the Invention

[0004] In view of this, some embodiments are, A step of mixing high work function metal oxide powder, indium oxide powder, and zinc oxide powder into a mixed powder in a predetermined mass ratio, The process involves adding a mixed powder to deionized water, adding a dispersant, and preparing a slurry. The process involves grinding the slurry with a high-energy sand mill, and adding a binder before the sand mill grinding is complete. The process involves spray granulation of a slurry to obtain spherical granulated powder, The process involves molding spherical granulated powder using a mold press and cold isostatic pressure to obtain a target material blank, The process includes degreasing and sintering a target material blank to obtain a high work function metal oxide target material, Here, the degreasing and sintering integration process is, specifically, The target material blank is placed in a degreasing and sintering furnace, the temperature is raised to a degreasing temperature of 450-650°C at a heating rate of 0.5-1°C / min, the temperature is maintained for 6-12 hours, the degreasing atmosphere is changed to air, and the air flow rate is set to 3-12 L / min. The heating rate is 0.5-3°C / min, the temperature is raised from the degreasing temperature to the first stage temperature of 900-1100°C, the temperature is maintained for 6-12 hours, the sintering atmosphere is changed to oxygen, and the oxygen flow rate is set to 3-12 L / min. The temperature should be raised from the first stage temperature to the second stage temperature of 1450-1550°C at a heating rate of 3-5°C / min, and no holding of temperature should be performed. The temperature is lowered from the second stage temperature to the third stage sintering temperature of 1150-1400°C at a cooling rate of 10-20°C / min, and then maintained at this temperature for 12-36 hours. The temperature is lowered from the third stage temperature to the fourth stage temperature of 600-800°C at a cooling rate of 1-3°C / min, then maintained for 3-6 hours, the sintering atmosphere is adjusted to air, and the air flow rate is set to 3-12 L / min. This includes lowering the temperature from the fourth stage to 200°C at a cooling rate of 3-10°C / min, followed by natural cooling to room temperature. A method for manufacturing a high work function metal oxide target material is disclosed.

[0005] In the method for producing high work function metal oxide target materials disclosed in several examples, the high work function metal oxide powder, indium oxide powder, and zinc oxide powder have a purity of 99.99% or higher and a particle size of 100 to 1000 nm.

[0006] In the method for producing a high work function metal oxide target material disclosed in several embodiments, the mass ratio of zinc oxide powder to indium oxide powder is 10-20:80-90, and the ratio of the mass of the high work function metal oxide powder to the total mass of zinc oxide powder and indium oxide powder is 2-10:90-98.

[0007] In the methods for producing high work function metal oxide target materials disclosed in some examples, the high work function metal oxide powder is MoO3, CoO, WO3, NiO, or TiO2.

[0008] In the method for producing high work function metal oxide target materials disclosed in several examples, the mass of deionized water is 60-90% of the total mass of the mixed powder, the mass of the dispersant is 0.5-1.5% of the total mass of the mixed powder, the mass of the binder is 0.5-2% of the total mass of the mixed powder, and the viscosity of the slurry is 35-45 mPa·s.

[0009] In the methods for producing high work function metal oxide target materials disclosed in several embodiments, the ball-to-total powder mass ratio for high-energy sand mill grinding is 1 to 5:1, and the time is 20 to 80 mins.

[0010] In a method for producing a high work function metal oxide target material disclosed in several embodiments, the slurry is spray-granulated in a granulator, the intake temperature of the granulator is 200-300°C, the exhaust temperature is 80-100°C, and the frequency is 30-50 Hz.

[0011] In the method for manufacturing high work function metal oxide target materials disclosed in several embodiments, the mold press pressure is 30 to 80 MPa, and the cold isostatic pressing pressure is 200 to 350 MPa.

[0012] In the method for producing a high work function metal oxide target material disclosed in several embodiments, the relative density of the target material blank is 60% or higher.

[0013] The high work function metal oxide target materials disclosed in some embodiments are obtained by the above-described method for producing high work function metal oxide target materials, and have a relative density of 99.5% or more, a resistance of 0.2 to 6 mΩ·cm, and a work function of 5.0 to 6.5 eV.

[0014] In the method for producing a high work function metal oxide target material disclosed in the embodiments of the present invention, IZO having high transmittance and high electrical conductivity is selected as the base material, a high work function metal oxide is added, a spray granulation process is employed to obtain a mixed powder with a uniform dimensional distribution, a degreasing and sintering integration process is selected, and a multi-stage variable temperature sintering process is combined to sinter the target material blank under a predetermined oxygen flow rate, thereby suppressing abnormal growth of crystal grains, helping to obtain fine crystal grains, reducing the generation of oxygen vacancies, improving the density of the target material, and finally obtaining a high work function metal oxide target material with a uniformly refined structure. The high work function metal oxide target material disclosed in the embodiments of the present invention has a small crystal grain size, a uniform distribution, high density, and excellent electrical performance, and can be used in the production of flexible OLED anode layer thin film materials, simplifying the device structure, reducing costs, and improving efficiency. [Brief explanation of the drawing]

[0015] [Figure 1] This is an SEM image of the Mo-IZO spherical granulated powder from Example 1. [Figure 2] This is a phase structure diagram of the Mo-IZO target material in Example 1. [Modes for carrying out the invention]

[0016] The term "examples," as used herein, refers to any example described "exemplarily" and should not be interpreted as necessarily being preferable or advantageous to other examples. Unless otherwise specified, performance indicator tests in the examples of this application employ general test methods in the art. It should be understood that the terms used in this application are merely for describing specific embodiments and are not intended to limit the content disclosed herein.

[0017] Unless otherwise specified, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in which this application pertains. Any other test methods and technical means not specifically mentioned herein refer to experimental methods and technical means generally employed by those skilled in the art.

[0018] The terms “almost” and “about” as used herein are intended to describe small variations. For example, they may mean less than or equal to ±5%, such as less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.2%, less than or equal to ±0.1%, and less than or equal to ±0.05%. In this specification, numerical data presented in range form are used solely for convenience and brevity, and should therefore be flexibly interpreted to include not only the numbers explicitly listed as boundaries of the range, but also all independent numbers or subranges contained within that range. For example, the numerical range “1 to 5%” should be interpreted to include not only the explicitly listed values ​​from 1% to 5%, but also independent values ​​and subranges within the indicated range. Thus, this numerical range includes independent values ​​such as 2%, 3.5%, and 4%, and subranges such as 1% to 3%, 2% to 4%, and 3% to 5%. This principle applies equally to listing only a range of a single number. Furthermore, such interpretation applies regardless of the width or characteristics of the range.

[0019] In this specification including the claims, conjunctions such as "comprising", "including", "accompanied by", "having", "containing", "relating to", "falling within", etc. are to be understood as open-ended, that is, meaning "including but not limited to". Only the conjunctions "consisting of" and "composed of" are closed-type conjunctions.

[0020] To better explain the content of this application, various specific details are shown in the following specific embodiments. Those skilled in the art should understand that this application can still be implemented even without some specific details. In the embodiments, for the purpose of emphasizing the gist of this application, detailed descriptions of some methods, means, devices, apparatuses, etc. known to those skilled in the art are omitted.

[0021] The technical features disclosed by the embodiments of this application can be arbitrarily combined without contradiction, and the obtained technical solutions belong to the content disclosed by the embodiments of this application. It should be noted that the orientation or positional relationship indicated by terms such as "center", "vertical direction", "horizontal direction", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. described in this application is based on the orientation or positional relationship shown in the drawings, and is only for easily describing and simplifying the description of technical features, and does not explicitly or implicitly indicate that the shown device or element must have a specific orientation or be configured and operated in a specific orientation. Therefore, unless it conflicts with the context content, it should not be understood as limiting the present invention. Also, the terms "first", "second" are only for the purpose of explanation, and unless it conflicts with the context content, it should not be understood as explicitly or implicitly indicating relative importance.

[0022] In some embodiments, the method for manufacturing a high work function metal oxide target material is A step of mixing a high work function metal oxide powder, an indium oxide powder, and a zinc oxide powder into a mixed powder at a predetermined mass ratio. Generally, the high work function metal oxide powder, the indium oxide powder, and the zinc oxide powder have a purity of 99.99% or more, a particle size of 100 - 1000 nm, the mass ratio of the zinc oxide powder to the indium oxide powder is 10 - 20:80 - 90, the ratio of the mass of the high work function metal oxide powder to the total mass of the zinc oxide powder and the indium oxide powder is 2 - 10:90 - 98. By controlling the mass ratio of indium oxide to zinc oxide, a step of ensuring the density and conductivity of the high work function metal oxide target material. A step of putting the mixed powder into deionized water, adding a dispersant, and preparing a slurry. Generally, the mass of the deionized water is 60 - 90% of the total mass of the mixed powder, the mass of the dispersant is 0.5 - 1.5% of the total mass of the mixed powder, the mass of the binder is 0.5 - 2% of the total mass of the mixed powder, the viscosity of the slurry is 35 - 45 mPa·s. It is necessary to strictly control the content of deionized water, thereby ensuring that the solid content in the slurry is appropriate and the viscosity of the slurry is within an appropriate range, which helps to obtain a mixed powder slurry with a narrow particle size distribution by ball milling. The dispersant is beneficial for the dispersion of the mixed powder in deionized water and can improve the ball milling effect of the slurry. A step of performing high energy sand milling on the slurry and adding a binder before the end of the sand milling. The binder can increase the viscosity of the slurry, bind the particles in the slurry, improve the granulation performance of the slurry, and ensure that the slurry has a high sphericity after spray granulation, thereby facilitating the blank forming in the next step. Generally, the binder is added about 10 minutes before the end of the sand milling. The binder is a gel-like aqueous solution of polyvinyl alcohol with a concentration of 8 - 15%. Generally, the dispersant and the binder can be completely removed in the subsequent degreasing and sintering processes and will not affect the sintering performance of the high work function metal oxide target material. A process for spray granulating a slurry to obtain spherical granulated powder, wherein the spherical granulated powder has a high degree of dryness, high sphericity, and a uniform particle size distribution, and which can improve sintering activity and reduce sintering temperature in the subsequent degreasing and sintering process. A process to obtain a target material blank by molding spherical granulated powder with a mold press and cold isostatic pressing, wherein the mold press pressure is generally 30-80 MPa, the cold isostatic pressing pressure is 200-350 MPa, and the relative density of the target material blank is 60% or more. The process includes degreasing and sintering a target material blank to obtain a high work function metal oxide target material, Here, the degreasing and sintering integration process is, specifically, The target material blank is placed in a degreasing and sintering furnace, the temperature is raised to a degreasing temperature of 450-650°C at a heating rate of 0.5-1°C / min, and the temperature is maintained for 6-12 hours. The degreasing atmosphere is changed to air, and the air flow rate is set to 3-12 L / min. The air atmosphere can absorb and discharge grease gases. Introducing air during the degreasing stage allows for better removal of polymeric substances in the dispersant and binder. Maintaining the temperature at a constant level allows greases to volatilize from the blank, preventing them from affecting further densification of the target material. The heating process involves raising the temperature from the degreasing temperature to the first stage temperature of 900-1100°C at a heating rate of 0.5-3°C / min, holding the temperature for 6-12 hours, using an oxygen sintering atmosphere, and maintaining an oxygen flow rate of 3-12 L / min. Typically, to prevent excessive grain size increase due to prolonged holding time, the holding time at the first stage temperature should not exceed 25 hours. The first stage holding temperature is set within the phase change temperature range of the target material blank to completely change the phase and initiate initial shrinkage of the target material blank. The heating rate is 3-5°C / min, increasing the temperature from the first stage to the second stage (1450-1550°C) without holding the temperature. The second stage temperature is the highest temperature point and is not held. It is generally set according to the material system and is 50-200°C higher than the third stage temperature. This reaches the initiation temperature for grain growth in the target material blank, exciting grain growth and accelerating the densification rate. The process involves cooling the material from the second stage temperature to the third stage sintering temperature of 1150-1400°C at a cooling rate of 10-20°C / min, followed by holding the temperature for 12-36 hours. The third stage temperature is the longest holding temperature, set to maximize the shrinkage rate of the target material blank. At this stage, the grain growth pores close, significantly accelerating the densification process. The process involves cooling the sample from the third stage temperature to the fourth stage temperature of 600-800°C at a cooling rate of 1-3°C / min, holding the temperature for 3-6 hours, adjusting the sintering atmosphere to air, and maintaining an air flow rate of 3-12 L / min. The fourth stage temperature is set to prevent sample cracking at low temperatures due to excessive cooling. The oxygen atmosphere primarily functions at high temperatures to prevent the decomposition reaction of oxides at high temperatures, and therefore, to reduce costs, the oxygen atmosphere is adjusted to an air atmosphere. This includes lowering the temperature from the fourth stage to 200°C at a cooling rate of 3-10°C / min, followed by natural cooling to room temperature.

[0023] Typically, the sintering process is carried out in an oxygen atmosphere. Zinc oxide and indium oxide have different rates of volatilization at high temperatures, which is detrimental to the stability and densification of the target material components. The heating rate during sintering must not be too fast or too slow. If the heating rate is too fast, the target material blank will be heated unevenly, preventing a complete reaction and causing cracking of the target material. If the heating rate is too slow, the sintering time will be too long, which is detrimental to production.

[0024] Normally, the sintering temperature should not exceed 1600°C, as indium oxide decomposes rapidly at temperatures above 1600°C, making it unfavorable to obtain target materials with high crystallinity, high purity, and uniform morphology.

[0025] In some embodiments, the high work function metal oxide powder is MoO3, CoO, WO3, NiO, or TiO2.

[0026] In some embodiments, the ball-to-total powder mass ratio for high-energy sand mill grinding is 1 to 5:1, and the time is 20 to 80 mins. Generally, a slurry is placed in a high-energy sand mill grinder, and high-energy sand mill grinding is performed with zirconium dioxide ball mill grinding beads with a diameter of 1 mm. During the high-energy sand mill grinding process, the mixed powder particles in the slurry are ground, resulting in smaller powder particles, a smaller particle size distribution range, and the formation of nanoparticles with a uniform distribution, which is useful in the subsequent granulation process. The metal oxide powder in the slurry is efficiently sand-milled in the high-energy sand mill grinder, forming fine particle sizes and effectively improving the sintering activity of the powder.

[0027] In some examples, the slurry is placed in a sand mill grinder and circulated multiple times to obtain a slurry with a solid content of approximately 50-70%.

[0028] In some embodiments, the slurry after sand mill grinding is allowed to stand and age for a certain period of time to allow the crystal grains to grow sufficiently, with the crystal grain growth time generally being half an hour or more, preferably two hours or more.

[0029] In some embodiments, the rotational speed of the high-energy sand mill grinder is set to 300-600 r / min.

[0030] In some embodiments, spray granulation of the slurry is performed in a granulator, where the intake air temperature of the granulator is 200-300°C, the exhaust air temperature is 80-100°C, the frequency is 30-50 Hz, and the particle size of the resulting granulated powder is approximately 200-300 nm.

[0031] In some embodiments, the high work function metal oxide target material is obtained by the method for manufacturing the high work function metal oxide target material described above, and the relative density of the high work function metal oxide target material is 99.5% or higher, the resistance is 0.2 to 6 mΩ·cm, and the work function is 5.0 to 6.5 eV.

[0032] The following provides a more illustrative explanation of the technical details, along with examples.

[0033] (Example 1) Figure 1 is an SEM diagram of the Mo-IZO spherical granulated powder disclosed in Example 1. Figure 2 is a phase structure diagram of the Mo-IZO target material disclosed in Example 1.

[0034] Example 1 discloses a method for manufacturing a high work function metal oxide target material. The manufacturing method is as follows: A step of mixing 427.5g of ZnO powder, 712.5g of In2O3 powder, and 60g of MoO3 powder into a mixed powder, wherein the mass ratio of In2O3 to ZnO is 62.5:37.5 and the mass ratio of MoO3 to In2O3-ZnO is 5:95, The process involves adding a mixed powder to 720 g of deionized water and adding 12 g of dispersant to prepare a slurry, wherein the slurry has a solid content of 62.5% and a viscosity of 40 mPa·s. The slurry was subjected to high-energy sand mill grinding for 60 minutes. 10 minutes before the end of the sand mill grinding, 12 g of binder was added, and MoO3, In2O3, and ZnO were thoroughly mixed to refine the particles. Subsequently, the slurry was placed in a granulator and spray granulation was performed. The granulator's intake air temperature was 200°C, the exhaust air temperature was 80°C, and the frequency was 30 Hz. 984 g of spherical Mo-IZO granulated powder was obtained, with a powder recovery rate of approximately 82%. As shown in Figure 1, the Mo-IZO granulated powder exhibited good spherification, a uniform particle size distribution, and no powder aggregation. A process to obtain a target material blank with a relative density of approximately 63% by molding spherical granulated powder using a mold press and cold isostatic pressing to shrink it, wherein the mold press pressure is 30 MPa and the cold isostatic pressing pressure is 250 MPa, The target material blank is subjected to a degreasing and sintering integration process, specifically, The target material blank is placed in a degreasing and sintering furnace, heated to a degreasing temperature of 600°C at a heating rate of 0.5°C / min, maintained at this temperature for 12 hours, the degreasing atmosphere is changed to air, and the air flow rate is set to 6 L / min. The heating rate is 3°C / min, the temperature is raised from the degreasing temperature to the first stage temperature of 1000°C, then maintained at this temperature for 10 hours, the sintering atmosphere is changed to oxygen, and the oxygen flow rate is set to 6 L / min. The temperature is raised from the first stage temperature to the second stage temperature of 1450°C at a heating rate of 3°C / min, and no holding of temperature is performed. The temperature is lowered from the second stage temperature to the third stage sintering temperature of 1350°C at a cooling rate of 20°C / min, and then maintained at this temperature for 20 hours. The temperature is lowered from the third stage temperature to the fourth stage temperature of 800°C at a cooling rate of 3°C / min, then maintained for 3 hours, the sintering atmosphere is adjusted to air, and the air flow rate is set to 6 L / min. The degreasing and sintering integration process includes lowering the temperature from the fourth stage to 200°C at a cooling rate of 5°C / min, followed by natural cooling to room temperature. The process includes obtaining a Mo-IZO target material having a relative density of 99.8%, a resistivity of 0.80 mΩ·cm, and a work function of 5.8 eV. As shown in Figure 2, the Mo-IZO target material had small and uniformly distributed grain sizes, no obvious gaps, and high density.

[0035] (Example 2) Example 2 discloses a method for producing a high work function metal oxide target material. Referring to Example 1, 450 g of ZnO powder, 690 g of In2O3 powder, and 96 g of MoO3 powder were weighed out, and the mass ratio of MoO3 to In2O3-ZnO was 8:92. 960 g of spherical Mo-IZO granulated powder was obtained, with a powder recovery rate of approximately 80%. The relative density of the obtained target material blank was 63%, the relative density of the obtained Mo-IZO target material was 99.6%, the resistivity was 0.42 mΩ·cm, and the work function was 6.0 eV.

[0036] (Example 3) Example 3 discloses a method for producing a high work function metal oxide target material. Referring to Example 1, MoO3 powder was replaced with WO3 powder, 427.5 g of ZnO powder, 712.5 g of In2O3 powder, and 90 g of WO3 powder were weighed out, and the mass ratio of WO3 to In2O3-ZnO was 5:95. The obtained spherical W-IZO granulated powder had a powder recovery rate of approximately 85%, the relative density of the obtained target material blank was 61%, the relative density of the obtained W-IZO target material was 99.6%, the resistivity was 5.0 mΩ·cm, and the work function was 5.2 eV.

[0037] (Example 4) Example 4 discloses a method for producing a high work function metal oxide target material. Referring to Example 3, 450 g of ZnO powder, 690 g of In2O3 powder, and 96 g of WO3 powder were weighed out, with a mass ratio of WO3 to In2O3-ZnO of 8:92. The resulting spherical W-IZO granulated powder had a powder recovery rate of approximately 86%, a relative density of 63% for the resulting target material blank, a relative density of 99.6% for the resulting W-IZO target material, a resistivity of 3.0 mΩ·cm, and a work function of 5.3 eV.

[0038] (Example 5) Example 5 discloses a method for producing a high work function metal oxide target material. Referring to Example 1, MoO3 powder was replaced with TiO2 powder, 427.5 g of ZnO powder, 712.5 g of In2O3 powder, and 90 g of TiO2 powder were weighed out, and the mass ratio of TiO2 to In2O3-ZnO was 5:95. The obtained spherical Ti-IZO granulated powder had a powder recovery rate of approximately 86%, the relative density of the obtained target material blank was 61%, the relative density of the obtained Ti-IZO target material was 99.5%, the resistivity was 5.2 mΩ·cm, and the work function was 5.5 eV.

[0039] (Example 6) Example 6 discloses a method for producing a high work function metal oxide target material. Referring to Example 5, 450 g of ZnO powder, 690 g of In2O3 powder, and 96 g of TiO2 powder were weighed out, with a mass ratio of TiO2 to In2O3-ZnO of 8:92. The resulting spherical Ti-IZO granulated powder had a powder recovery rate of approximately 85%, a relative density of 62% for the resulting target material blank, a relative density of 99.8% for the resulting Ti-IZO target material, a resistivity of 3.2 mΩ·cm, and a work function of 5.7 eV.

[0040] The method for producing a high work function metal oxide target material disclosed in the embodiments of the present invention involves selecting IZO, which has high transmittance and high electrical conductivity, as the base material, adding a high work function metal oxide, employing a spray granulation process to obtain a mixed powder with a uniform dimensional distribution, selecting a degreasing and sintering integration process, combining it with a multi-stage variable temperature sintering process, and sintering the target material blank under a predetermined oxygen flow rate. This suppresses abnormal growth of crystal grains, helps to obtain fine crystal grains, reduces the generation of oxygen vacancies, improves the density of the target material, and ultimately obtains a high work function metal oxide target material with a uniformly refined structure. The high work function metal oxide target material disclosed in the embodiments of the present invention has a small crystal grain size, a uniform distribution, high density, and excellent electrical performance, and can be used in the production of flexible OLED anode layer thin film materials, simplifying the device structure, reducing costs, and improving efficiency.

[0041] The technical solutions disclosed in this invention and the technical details disclosed in the examples are merely illustrative examples illustrating the inventive concept of this invention and are not intended to limit the technical solutions of this invention. Any ordinary modifications, replacements, or combinations of the technical details disclosed in the examples of this invention all have the same inventive concept as this invention and are all within the scope of protection of the claims of this invention.

Claims

1. A step of mixing high work function metal oxide powder, indium oxide powder, and zinc oxide powder into a mixed powder in a predetermined mass ratio, The process involves adding a mixed powder to deionized water, adding a dispersant, and preparing a slurry. The process involves grinding the slurry with a high-energy sand mill, and adding a binder before the sand mill grinding is complete. The process involves spray granulation of a slurry to obtain spherical granulated powder, The process involves molding spherical granulated powder using a mold press and cold isostatic pressure to obtain a target material blank, The process includes degreasing and sintering a target material blank to obtain a high work function metal oxide target material, The aforementioned degreasing and sintering integration process specifically involves, The target material blank is placed in a degreasing and sintering furnace, the temperature is raised to a degreasing temperature of 450-650°C at a heating rate of 0.5-1°C / min, and the temperature is maintained for 6-12 hours. The degreasing atmosphere is changed to air, and the air flow rate is set to 3-12 L / min. The heating rate is increased from the degreasing temperature to the first stage temperature of 900-1100°C at a rate of 0.5-3°C / min, followed by a holding period of 6-12 hours, with the sintering atmosphere being oxygen and the oxygen flow rate set to 3-12 L / min. The temperature should be raised from the first stage temperature to the second stage temperature of 1450-1550°C at a heating rate of 3-5°C / min, and no holding of temperature should be performed. The temperature is lowered from the second stage temperature to the third stage sintering temperature of 1150-1400°C at a cooling rate of 10-20°C / min, and then maintained at this temperature for 12-36 hours. The temperature is lowered from the third stage temperature to the fourth stage temperature of 600-800°C at a cooling rate of 1-3°C / min, then maintained for 3-6 hours, the sintering atmosphere is adjusted to air, and the air flow rate is set to 3-12 L / min. This includes lowering the temperature from the fourth stage to 200°C at a cooling rate of 3 to 10°C / min, followed by natural cooling to room temperature. A method for producing a high work function metal oxide target material, characterized by the following:

2. The method for producing a high work function metal oxide target material according to claim 1, characterized in that the high work function metal oxide powder, the indium oxide powder, and the zinc oxide powder have a purity of 99.99% or higher and a particle size of 100 to 1000 nm.

3. A method for producing a high work function metal oxide target material according to claim 1, characterized in that the mass ratio of the zinc oxide powder to the indium oxide powder is 10 to 20:80 to 90, and the ratio of the mass of the high work function metal oxide powder to the total mass of the zinc oxide powder and the indium oxide powder is 2 to 10:90 to 98.

4. The aforementioned high work function metal oxide powder is MoO ３ CoO, WO ３ NiO or TiO ２ A method for producing a high work function metal oxide target material according to claim 1, characterized in that...

5. A method for producing a high work function metal oxide target material according to claim 1, characterized in that the mass of the deionized water is 60 to 90% of the total mass of the mixed powder, the mass of the dispersant is 0.5 to 1.5% of the total mass of the mixed powder, the mass of the binder is 0.5 to 2% of the total mass of the mixed powder, and the viscosity of the slurry is 35 to 45 mPa·s.

6. The method for producing a high work function metal oxide target material according to claim 1, characterized in that the ball-to-total powder mass ratio of the high-energy sand mill grinding is 1 to 5:1 and the time is 20 to 80 mins.

7. The method for producing a high work function metal oxide target material according to claim 1, characterized in that the spray granulation of the slurry is performed in a granulator, the intake temperature of the granulator is 200 to 300°C, the exhaust temperature is 80 to 100°C, and the frequency is 30 to 50 Hz.

8. A method for producing a high work function metal oxide target material according to claim 1, characterized in that the pressure of the mold press is 30 to 80 MPa and the pressure of the cold isostatic press is 200 to 350 MPa.

9. A method for producing a high work function metal oxide target material according to claim 1, characterized in that the relative density of the target material blank is 60% or more.

10. A high work function metal oxide target material obtained by a method for producing a high work function metal oxide target material according to any one of claims 1 to 9, characterized in that the relative density is 99.5% or more, the resistance is 0.2 to 6 mΩ·cm, and the work function is 5.0 to 6.5 eV.

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