Co-doped IZO high-density ceramic material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of transparent conductive oxide target materials, and particularly relates to a co-doped IZO high-density ceramic material and a preparation method and application thereof. The co-doped IZO high-density ceramic material provided by the invention comprises main components and doping components, the main components comprise indium oxide and zinc oxide, and the doping components comprise hafnium oxide and yttrium oxide; the mass ratio of indium oxide to zinc oxide to hafnium oxide to yttrium oxide is (87-93): (7-13): (0.1-5): (0.1-2); the relative density of the co-doped IZO high-density ceramic material is greater than or equal to 96%. The co-doped IZO high-density ceramic material has few oxygen vacancy defects and has high density and low resistivity, and a transparent conductive oxide film prepared from the co-doped IZO high-density ceramic material has high mobility and high light transmittance.

Description

Technical Field

[0001] The present invention belongs to the technical field of transparent conductive oxide targets, and particularly relates to a co-doped IZO high-density ceramic material, a preparation method thereof, and an application thereof. Background Art

[0002] Transparent conductive oxide thin films are a kind of wide-bandgap oxide semiconductor materials, which have both good electrical conductivity and light transmittance. Such materials have been widely used in various electronic devices such as displays, touch panels, LED light-emitting devices, solar cells, and transistors. Among common transparent conductive oxides, indium zinc oxide (IZO) thin films have been widely studied due to their high electron mobility, large on / off ratio, good uniformity, good light transmittance, and stable electrical properties. In particular, IZO thin films can maintain a high mobility in the amorphous state, and excellent transparent electrode quality can be achieved without a high deposition temperature, and they can be effectively applied to flexible and bendable electronic devices. However, due to the intrinsic point defects of ZnO, especially zinc interstitials and oxygen vacancies, deep-level defects exist above the valence band top of IZO thin films, and the existence of these defects will affect the optoelectronic properties of IZO thin films. Doping different elements (such as Ga, Mg, Nb, Ln series elements, etc.) into IZO thin films can effectively reduce deep-level defects, improve mobility, and improve the optoelectronic properties of IZO thin films.

[0003] The prior art discloses doping IZO targets with Sn, but due to the relatively large content of ZnO, the inherent defects of ZnO have not been completely overcome, affecting its optoelectronic properties (resistivity and mobility). The prior art also discloses doping IZO targets with Pr, but since its effect of suppressing oxygen vacancies in ZnO is limited, the negative impact of oxygen vacancies on optoelectronic properties still cannot be effectively solved. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a co-doped IZO high-density ceramic material, a preparation method thereof, and an application thereof. The co-doped IZO high-density ceramic material has few oxygen vacancy defects, high density, and low resistivity, and the transparent conductive oxide thin film prepared therefrom has high mobility and high light transmittance.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a co-doped IZO high-density ceramic material, including a main component and a doping component. The main component includes indium oxide and zinc oxide, and the doping component includes hafnium oxide and yttrium oxide;

[0007] The mass ratio of indium oxide, zinc oxide, hafnium oxide, and yttrium oxide is 87-93:7-13:0.1-5:0.1-2;

[0008] The relative density of the co-doped IZO high-density ceramic material is ≥ 96%.

[0009] Preferably, the resistivity of the co-doped IZO high-density ceramic material is 1.4 - 3.9 mΩ·cm, and the flexural strength is 112 - 178 MPa.

[0010] 3. The preparation method of the co-doped IZO high-density ceramic material according to claim 1 or 2, characterized by comprising the following steps:

[0011] Mix indium oxide powder, zinc oxide powder, hafnium oxide powder, yttrium oxide powder, dispersant, binder, defoamer and water to make a slurry, and successively ball-mill and granulate the obtained mixed slurry to obtain mixed powder;

[0012] Mold the mixed powder, and sinter the obtained green body to obtain the co-doped IZO high-density ceramic material.

[0013] Preferably, the sintering includes degreasing sintering, pre-sintering and high-temperature sintering carried out in sequence; the temperature of the degreasing sintering is 600 - 750 °C, and the heat preservation time is 5 - 10 h; the pre-sintering is to raise the temperature from the temperature of the degreasing sintering to 1500 - 1600 °C; the temperature of the high-temperature sintering is 1300 - 1550 °C, and the heat preservation time is 12 - 36 h.

[0014] Preferably, the rotation speed of the ball-milling is 2000 - 3000 rpm; the ball-milling time is 1 - 8 h; the ball-to-material ratio of the ball-milling is 1:1 - 2; the ball-milling beads used for the ball-milling include three kinds of ball-milling beads with diameters of 0.1 mm, 0.3 mm and 0.6 mm respectively, and the weight ratio of the three kinds of ball-milling beads is 1 - 5:1 - 5:1 - 5.

[0015] Preferably, the molding includes cold pressing molding treatment and cold isostatic pressing molding treatment carried out in sequence; the pressure of the cold pressing molding treatment is 20 - 40 MPa, and the pressure maintaining time is 1 - 3 min; the pressure of the cold isostatic pressing molding treatment is 250 - 300 MPa, and the pressure maintaining time is 20 - 60 min.

[0016] Preferably, the particle size D50 of the solid in the mixed slurry after ball-milling is < 0.2 μm, and the particle size D90 is < 0.6 μm.

[0017] The present invention also provides the application of the co-doped IZO high-density ceramic material described in the above technical solution or the co-doped IZO high-density ceramic material prepared by the preparation method described in the above technical solution as a target in the preparation of a transparent conductive oxide film.

[0018] The present invention also provides a transparent conductive oxide film, which is obtained by sputtering and coating a target on a substrate;

[0019] The target material is the co-doped IZO high-density ceramic material described in the above technical solution or the co-doped IZO high-density ceramic material prepared by the preparation method described in the above technical solution.

[0020] Preferably, the thickness of the transparent conductive oxide film is 50-150 nm, the mobility is 22-35 cm 2 V -1 S -1 , and the light transmittance is 83.2-89.6%.

[0021] The present invention provides a co-doped IZO high-density ceramic material, which includes a main component and a doping component. The main component includes indium oxide and zinc oxide, and the doping component includes hafnium oxide and yttrium oxide; the mass ratio of indium oxide, zinc oxide, hafnium oxide and yttrium oxide is 87-93:7-13:0.1-5:0.1-2; the relative density of the co-doped IZO high-density ceramic material is ≥96%. The present invention uses hafnium oxide and yttrium oxide doping. Since Hf-O has a very high bond energy, second only to Th-O and Ta-O, and at the same time the electronegativity difference between Hf and O is greater than the electronegativity difference between In and Zn and O, hafnium atoms are easy to combine with oxygen, which is beneficial to reducing oxygen vacancies in the doped IZO ceramic material, reducing the carrier concentration, reducing the resistivity, and increasing the mobility. At the same time, the ionic radius of hafnium is similar to that of indium ions, and it is easier to dissolve into indium oxide, promoting densification. Moreover, the high band gap of hafnium oxide and yttrium oxide can improve the light transmittance of the film, so that the co-doped IZO high-density ceramic material has a high density and a low resistivity, and the transparent conductive oxide film prepared therefrom has a high mobility and a high light transmittance.

[0022] The present invention also provides a preparation method of the above co-doped IZO high-density ceramic material. Yttrium oxide can effectively reduce the grain size during sintering, and can improve the dispersion of metal oxide powder, which is beneficial to discharging pores and enhancing the strength of the co-doped IZO high-density ceramic material. At the same time, it can also reduce the sintering temperature, increase the sintering speed, realize the preparation of a co-doped IZO high-density ceramic material with low defects, high density and low resistance, and further improve the optoelectronic properties of the film prepared by sputtering coating with it. Specific Embodiments

[0023] The present invention provides a co-doped IZO high-density ceramic material, which includes a main component and a doping component. The main component includes indium oxide and zinc oxide, and the doping component includes hafnium oxide and yttrium oxide;

[0024] The mass ratio of indium oxide, zinc oxide, hafnium oxide and yttrium oxide is 87-93:7-13:0.1-5:0.1-2;

[0025] The relative density of the co-doped IZO high-density ceramic material is ≥ 96%.

[0026] Unless otherwise specified, the present invention has no special requirements for the sources of the raw materials used, and commercially available products well-known to those skilled in the art can be adopted.

[0027] As an embodiment, the mass ratio of indium oxide, zinc oxide, hafnium oxide and yttrium oxide is 87 - 90:8 - 12:0.5 - 2:0.1 - 1.5, and in specific embodiments, it is 87 - 89:9 - 12:0.5 - 1.7:0.1 - 1.5.

[0028] As an embodiment, the relative density of the co-doped IZO high-density ceramic material is ≥ 96%, and in specific embodiments, it is 96.18%, 96.53%, 97.38%, 98.21%, 98.53%, 99.12%, 99.36% or 99.52%; the resistivity is 1.4 - 3.9 mΩ·cm, and in specific embodiments, it is 1.4 mΩ·cm, 1.9 mΩ·cm, 2.1 mΩ·cm, 2.3 mΩ·cm, 2.5 mΩ·cm, 3.8 mΩ·cm or 3.9 mΩ·cm; the flexural strength is 112 - 178 MPa, and in specific embodiments, it is 112 MPa, 122 MPa, 131 MPa, 153 MPa, 158 MPa, 162 MPa, 166 MPa or 178 MPa.

[0029] The co-doping of hafnium oxide and yttrium oxide to form a eutectic is beneficial to improving the densification and strength of the co-doped IZO high-density ceramic material. The co-doping of hafnium oxide and yttrium oxide can promote the formation of a liquid phase or a eutectic with a low melting point. During the liquid-phase sintering process, yttrium oxide as a sintering aid can help hafnium oxide form a dense microstructure at a lower temperature. The formation of the liquid phase is usually accompanied by a lower melting point, which helps to increase the sintering rate and reduce energy consumption, and promotes the densification of sintering. In addition, hafnium oxide with a strong binding force to oxygen is beneficial to reducing oxygen vacancies, lowering the resistivity and increasing the mobility. At the same time, the high band gap of hafnium oxide and yttrium oxide can improve the light transmittance of the thin film, so that the co-doped IZO high-density ceramic material has a high density and a low resistivity, and the transparent conductive oxide thin film prepared therefrom has a high mobility and a high light transmittance.

[0030] The present invention also provides a preparation method of the co-doped IZO high-density ceramic material according to the above technical solution, comprising the following steps:

[0031] Mix indium oxide powder, zinc oxide powder, hafnium oxide powder, yttrium oxide powder, a dispersant, a binder, an antifoaming agent and water to make a slurry, and successively ball-mill and granulate the obtained mixed slurry to obtain mixed powder;

[0032] The mixed powder is formed, and the obtained green body is sintered to obtain the co-doped IZO high-density ceramic material.

[0033] In the present invention, indium oxide powder, zinc oxide powder, hafnium oxide powder, yttrium oxide powder, a dispersant, a binder, an antifoaming agent and water are mixed to make a slurry, and the obtained mixed slurry is successively ball-milled and granulated to obtain a mixed powder.

[0034] As an embodiment, the particle size D50 of the indium oxide powder, zinc oxide powder, hafnium oxide powder and yttrium oxide powder is independently < 3 μm, and in specific embodiments, it is < 2 μm.

[0035] As an embodiment, the dispersant includes an alcohol dispersant and / or an acid dispersant, and in specific embodiments, it is an acid dispersant; the alcohol dispersant includes polyvinyl alcohol and / or polypropylene alcohol, and in specific embodiments, it is polypropylene alcohol; the acid dispersant includes one or more of polyacrylic acid, polymethacrylic acid and sodium polyacrylate, and in specific embodiments, it is polyacrylic acid; the mass of the dispersant is 0.5-2.5% of the total mass of the indium oxide powder, zinc oxide powder, hafnium oxide powder and yttrium oxide powder, and in specific embodiments, it is 1-2%.

[0036] The main function of the dispersant is to evenly disperse the metal oxide powder in the slurry and prevent particle aggregation and caking.

[0037] As an embodiment, the binder is one or more of polyvinyl alcohol, polyethylene, polypropylene and polyvinyl chloride, and in specific embodiments, it is polyvinyl alcohol; the mass of the binder is 0.1-6.6% of the total mass of the indium oxide powder, zinc oxide powder, hafnium oxide powder and yttrium oxide powder, and in specific embodiments, it is 3-6%.

[0038] The function of the binder is to adjust the viscosity and rheological properties of the slurry, which is beneficial to the densification of the subsequent green body by hydraulic pressure.

[0039] As an embodiment, the antifoaming agent includes an alkane antifoaming agent and / or a fatty acid antifoaming agent, and in specific embodiments, it is a fatty acid antifoaming agent; the alkane antifoaming agent includes ethylene oxide and / or propylene oxide, and in specific embodiments, it is ethylene oxide; the fatty acid antifoaming agent includes one or more of lauric acid, palmitic acid and polyacrylate, and in specific embodiments, it is polyacrylate; the mass of the antifoaming agent is 0.01-0.5% of the total mass of the indium oxide powder, zinc oxide powder, hafnium oxide powder and yttrium oxide powder, and in specific embodiments, it is 0.1-0.3%.

[0040] The function of the antifoaming agent is to eliminate the bubbles during the ball-milling process. The presence of bubbles will not only affect the stirring efficiency but also may cause uneven ball-milling of the slurry.

[0041] As an implementation manner, the water is deionized water; the mass of the water is 50-60% of the total mass of indium oxide powder, zinc oxide powder, hafnium oxide powder and yttrium oxide powder, and is 50-55% in specific embodiments.

[0042] As an implementation manner, the mixing and pulping are carried out under stirring; the stirring rate is 500-1500 rpm, and is 800-1000 rpm in specific embodiments; the stirring time is 0.5-2 h, and is 1-1.5 h in specific embodiments.

[0043] As an implementation manner, the equipment used for ball milling is a sand mill; the rotation speed of the ball milling is 2000-3000 rpm, and is 2250-2500 rpm in specific embodiments; the ball milling time is 1-8 h, and is 2-5 h in specific embodiments; the ball-to-material ratio of the ball milling is 1:1-2, and is 1:1 in specific embodiments; the ball milling beads used for the ball milling are zirconia beads; the ball milling beads used for the ball milling include three kinds of ball milling beads with diameters of 0.1 mm, 0.3 mm and 0.6 mm respectively, and the weight ratio of the three kinds of ball milling beads is 1-5:1-5:1-5, and is 1:1:1 in specific embodiments. Ball milling beads with different diameters can optimize the grinding efficiency, improve the particle size distribution and enhance the dispersion effect.

[0044] As an implementation manner, the particle size D50 of the solid in the mixed slurry after ball milling is <0.2 μm, and the particle size D90 is <0.6 μm, and is D50 = 0.15 μm and D90 = 0.55 μm in specific embodiments. The slurry with small particle size and narrow distribution after ball milling will have a more uniform microstructure when forming a green body, which helps to improve the sinterability, and the density of the sintered product will also be higher, improving the hardness and strength of the sintered product.

[0045] As an implementation manner, the granulation is spray drying granulation; the temperature of the spray drying granulation is 100-250 °C, and is 200-240 °C in specific embodiments. The present invention has no special limitation on the time of the spray drying granulation, as long as granulation can be achieved.

[0046] As an implementation manner, after the granulation, the present invention further includes: screening the granulated material obtained from the granulation; the mesh number of the sieve used for the screening is 60-100 meshes, and is 70-90 meshes in specific embodiments. Screening can separate the granulated material with large particle size obtained from granulation. The finer granulated material has a larger specific surface area and is more likely to diffuse and combine at high temperature, which is beneficial to improving the sintering rate and density of the granulated material.

[0047] After obtaining the mixed powder, the present invention forms the mixed powder, and the obtained green body is sintered to obtain the co-doped IZO high-density ceramic material.

[0048] As an implementation manner, the shaping includes cold pressing shaping treatment and cold isostatic pressing shaping treatment carried out successively; the pressure of the cold pressing shaping treatment is 20 - 40 MPa, specifically 25 - 35 MPa in specific embodiments, the pressure holding time is 1 - 3 min, specifically 2 min in specific embodiments; the pressure of the cold isostatic pressing shaping treatment is 250 - 300 MPa, specifically 260 - 280 MPa in specific embodiments, and the pressure holding time is 20 - 60 min, specifically 25 - 50 min in specific embodiments.

[0049] The function of the cold pressing shaping treatment is to press the mixed powder into a corresponding shape, that is, the corresponding green body shaping. The cold pressing pressure determines the fluidity of the material and the degree of plastic deformation during shaping; too large a pressure will cause wear of the mold, and the pressure holding time affects the effect and efficiency of the shaping process.

[0050] The cold isostatic pressing shaping treatment is to further improve the density, uniformity and strength of the green body and reduce defects. The magnitude of the pressure and the length of the time will both affect the density, uniformity and strength of the final shaped green body.

[0051] As an implementation manner, the sintering includes degreasing sintering, pre-sintering and high-temperature sintering carried out successively; the temperature of the degreasing sintering is 600 - 750 °C, specifically 650 - 750 °C in specific embodiments, the heat preservation time is 5 - 10 h, specifically 7 - 10 h in specific embodiments; the heating rate for heating up to the temperature of the degreasing sintering is 0.5 - 1 °C / min, specifically 0.5 - 0.8 °C / min in specific embodiments; the pre-sintering is heating up from the temperature of the degreasing sintering to 1500 - 1600 °C, specifically 1500 - 1550 °C in specific embodiments; the heating rate is 1 - 5 °C / min, specifically 2 - 4 °C / min in specific embodiments; the temperature of the high-temperature sintering is 1300 - 1550 °C, specifically 1350 - 1450 °C in specific embodiments, the heat preservation time is 12 - 36 h, specifically 16 - 24 h in specific embodiments; the cooling rate for cooling down from the temperature of the pre-sintering to the temperature of the high-temperature sintering is 5 - 10 °C / min, specifically 7 - 10 °C / min in specific embodiments.

[0052] As an implementation manner, during the sintering process, when the temperature of the sintering is not higher than 1000 °C, the sintering is carried out in air, and when the temperature of the sintering is higher than 1000 °C, the sintering is carried out in oxygen; the flow rate of the oxygen is 10 - 50 L / min, specifically 20 - 40 L / min in specific embodiments.

[0053] The function of degreasing sintering is to remove polymers such as defoamers, binders, and dispersants added during the ball milling process. Pre-sintering prepares for high-temperature sintering and increases the bonding force between metal oxide powders. High-temperature sintering is to obtain a sintered product with high density and high strength. Appropriate temperature and time are required to prepare the co-doped IZO high-density ceramic material, and the control of the cooling rate is to avoid cracks or deformation.

[0054] During the sintering process, yttrium ions of yttrium oxide can form a solid solution with indium zinc oxide or produce an interface fixation effect, enhancing the stability of the grain boundary. This effect can inhibit the excessive growth of grains and thus reduce the grain size. Yttrium oxide will form a stable oxide film during the sintering process, covering the particle surface. This film can effectively hinder the growth of grains and play a role in grain boundary strengthening, thereby controlling the grain size. Yttrium oxide can inhibit the excessive growth of grains. The sintered body obtained after sintering usually has a smaller grain size. According to the hall-petch relationship, grain refinement can significantly improve the yield strength and flexural strength of the material. The smaller the grains, the higher the material strength. Yttrium oxide has a relatively high surface energy and can form good contact with other metal oxides through surface chemical interactions (such as van der Waals forces and chemical bonding). Therefore, it can help improve the dispersibility of metal oxide powders and is conducive to promoting the discharge of pores. Yttrium oxide acts as a sintering aid during the sintering process to optimize the densification of the sintered product by reducing the sintering temperature and increasing the sintering speed. The addition of yttrium oxide can promote the bonding and spreading of metal oxide particles at a lower temperature, thereby improving the sintering efficiency. Yttrium oxide can form a liquid phase during the sintering process. This liquid phase can help the metal oxide particles stick together more easily and reduce the contact angle between particles, effectively improving the fluidity of the particles and promoting the diffusion between particles, thus accelerating the sintering process.

[0055] As an implementation manner, after the sintering, it further includes: naturally cooling the sintered product to room temperature.

[0056] The present invention also provides the application of the co-doped IZO high-density ceramic material described in the above technical solution or the co-doped IZO high-density ceramic material prepared by the preparation method described in the above technical solution as a target in the preparation of a transparent conductive oxide film.

[0057] The present invention also provides a transparent conductive oxide film, which is obtained by sputtering and coating a target on a substrate;

[0058] The target is the co-doped IZO high-density ceramic material described in the above technical solution or the co-doped IZO high-density ceramic material prepared by the preparation method described in the above technical solution.

[0059] As an implementation manner, the preparation method of the target includes the following steps: mechanically grinding and processing the co-doped IZO high-density ceramic material according to the drawing size to obtain the target.

[0060] As an implementation manner, the substrate is a glass substrate; before sputtering coating, the present invention further includes: pre-treating the substrate, and the pre-treatment is sequentially cleaning with acetone, ethanol and deionized water, and then drying with nitrogen.

[0061] As an implementation manner, the sputtering coating is magnetron sputtering coating; the power of the sputtering coating is 120-200 W, specifically 150-180 W in the specific embodiment, and the sputtering gas pressure of the sputtering coating is 0.3-0.5 Pa, specifically 0.4 Pa in the specific embodiment.

[0062] As an implementation manner, the thickness of the transparent conductive oxide film is 50-150 nm, specifically 70-100 nm in the specific embodiment, and the mobility is 22-35 cm 2 V -1 S -1 , specifically 22 cm 2 V -1 S -1 , 23 cm 2 V -1 S -1 , 25 cm 2 V - 1 S -1 , 27 cm 2 V -1 S -1 , 28 cm 2 V -1 S -1 , 29 cm 2 V -1 S -1 , 33 cm 2 V -1 S -1 or 35 cm 2 V -1 S -1 , and the light transmittance is 83.2-89.6%, specifically 83.2%, 84.7%, 86.5%, 87.6%, 87.8%, 88.3%, 88.4% or 89.6% in the specific embodiment.

[0063] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention, but they cannot be understood as limiting the protection scope of the present invention.

[0064] Example 1

[0065] Weigh indium oxide powder, zinc oxide powder, hafnium oxide powder and yttrium oxide powder with particle sizes D50 all < 2 μm according to a mass ratio of 87.6:10.6:1.5:0.3, put them into a ball mill tank. At the same time, based on the total mass of indium oxide powder, zinc oxide powder, hafnium oxide powder and yttrium oxide powder, add 50% deionized water, 1.44% dispersant (polyacrylic acid), 5.02% binder (polyvinyl alcohol), 0.1% defoamer (acrylate), stir for 1.5 h at 1000 rpm to make a slurry. Place the obtained mixed slurry in a sand mill for ball milling. The ball milling speed is 2250 rpm, the ball-to-material ratio is 1:1, and the ball milling beads are three kinds of zirconia beads with diameters of 0.1 mm, 0.3 mm and 0.6 mm respectively (weight ratio is 1:1:1). The ball milling time is 4 h. The particle sizes of the solids in the mixed slurry after ball milling are D50 = 0.15 μm and D90 = 0.55 μm. After the ball milling is completed, the granulated materials obtained by spray granulation at 235 °C are screened with an 80-mesh sieve to obtain mixed powder;

[0066] Perform cold pressing forming treatment on the mixed powder at 27.3 MPa, with a holding pressure time of 2 min, and then perform cold isostatic pressing forming treatment at 270 MPa, with a holding pressure time of 25 min to obtain a green body;

[0067] Place the green body in a sintering furnace and perform degreasing sintering, pre-sintering and high-temperature sintering in sequence. The degreasing sintering is to raise the temperature to 750 °C at a rate of 0.5 °C / min, and the holding time is 10 h; the pre-sintering is to raise the temperature from the temperature of the degreasing sintering to 1500 °C at a rate of 3 °C / min without holding; the high-temperature sintering is to lower the temperature from the temperature of the pre-sintering to 1400 °C at a rate of 10 °C / min and hold for 24 h. During the sintering process, air is introduced when the temperature is not higher than 1000 °C, and oxygen is passed through when the temperature is higher than 1000 °C. The oxygen flow rate is 30 L / min. After the sintering is completed, it is naturally cooled to room temperature to obtain a co-doped IZO high-density ceramic material;

[0068] Perform mechanical grinding on the co-doped IZO high-density ceramic material according to the drawing size to obtain a co-doped IZO high-density ceramic target for magnetron sputtering.

[0069] Examples 2 - 8

[0070] The differences between Examples 2 - 8 and Example 1 are shown in Table 1.

[0071] Table 1 Process parameters and component contents of each example

[0072]

[0073] Comparative Example 1

[0074] The preparation method of Comparative Example 1 was the same as that of Example 1, except that the components were 87.6% indium oxide, 10.9% zinc oxide, and 1.5% hafnium oxide.

[0075] Comparative Example 2

[0076] The preparation method of Comparative Example 2 was the same as that of Example 1, except that the components were 87.6% indium oxide, 10.9% zinc oxide, and 1.5% yttrium oxide.

[0077] Performance Test

[0078] 1. Processing and Bonding:

[0079] The target materials prepared in the above examples and comparative examples were processed according to the drawing dimensions, then bonded to titanium tubes, and ultrasonic inspection for damage was carried out. There were no hidden cracks, and then subsequent coating tests were carried out.

[0080] 2. Coating Test:

[0081] Target Material Density: The co-doped IZO high-density ceramic target materials prepared were measured using the Archimedes drainage method.

[0082] Resistivity: The co-doped IZO high-density ceramic target materials prepared were measured using a four-probe resistivity tester.

[0083] Flexural Strength: The co-doped IZO high-density ceramic target materials prepared were measured using a universal testing machine.

[0084] On glass substrates that had been cleaned with acetone, ethanol, deionized water and dried with nitrogen, the target materials prepared in the above examples and comparative examples were used respectively to deposit transparent conductive oxide films by magnetron sputtering coating. The coating power was 180 W, the sputtering gas pressure was 0.4 Pa, and the film thickness was 100 nm.

[0085] Film Mobility: The prepared transparent conductive oxide films were tested using a Hall effect tester.

[0086] Film Transmittance: The prepared transparent conductive oxide films were tested using an ultraviolet spectrophotometer, and the test wavelength was 400 - 1200 nm.

[0087] The performance test results of the target materials prepared in each example and comparative example, and the films prepared therefrom are shown in Table 2.

[0088] Table 2 Performance Test Results of Each Example and Comparative Example

[0089]

[0090]

[0091] As can be seen from the performance test results in Table 2, the co-doped IZO high-density ceramic target prepared by the present invention has a high density and a low resistivity. The transparent conductive oxide film prepared from this co-doped IZO high-density ceramic target has good mobility and light transmittance, and can meet the requirements of the optoelectronic properties (mobility and transmittance) of the transparent conductive film.

[0092] In Examples 1 to 5 of the present invention, the usage amounts of the raw materials in the co-doped IZO high-density ceramic target are different, and the selection of each raw material component in Example 1 is more appropriate. By comparing Examples 6, 7, 8 with Example 1, it can be seen that when sintered at a low temperature, the target cannot be completely densified, while when sintered at a high temperature, the volatilization of indium oxide and zinc oxide may occur. Therefore, appropriate sintering temperature and sintering time are more conducive to improving the density and optoelectronic properties of the target. In Comparative Example 1, only 1.5% of hafnium oxide is doped, and in Comparative Example 2, only 1.5% of yttrium oxide is doped. It can be found that compared with Example 1, the target properties of Comparative Examples 1 and 2 are lower, which further affects the properties of the film, indicating that the single doping of hafnium oxide or yttrium oxide has limited influence on the properties of the co-doped IZO high-density ceramic target. This is because the co-doping of hafnium oxide and yttrium oxide to form a eutectic helps to improve the density and strength of the target. At a certain ratio, the co-doping of hafnium oxide and yttrium oxide can promote the formation of a liquid phase or a eutectic with a low melting point. During the liquid-phase sintering process, yttrium oxide, as a sintering aid, can help hafnium oxide form a dense microstructure at a lower temperature. The formation of the liquid phase is usually accompanied by a lower melting point, which helps to increase the sintering rate and reduce energy consumption, promoting the densification of sintering. In addition, hafnium oxide, which has a strong binding force with oxygen, is beneficial to reducing oxygen vacancies and improving mobility. At the same time, the high band gaps of hafnium oxide and yttrium oxide can improve the light transmittance of the film. Therefore, the comprehensive performance of the target is improved.

[0093] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention rather than all embodiments. People can also obtain other embodiments based on these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A co-doped IZO high-density ceramic material, characterized in that: The invention comprises a main component and a doping component, wherein the main component comprises indium oxide and zinc oxide, and the doping component comprises hafnium oxide and yttrium oxide; The mass ratio of indium oxide, zinc oxide, hafnium oxide and yttrium oxide is 87-93:7-13:0.1-5:0.1-2; The relative density of the co-doped IZO high-density ceramic material is ≥96%.

2. The co-doped IZO high-density ceramic material according to claim 1, characterized in that: The co-doped IZO high-density ceramic material has a resistivity of 1.4 to 3.9 mΩ·cm and a bending strength of 112 to 178 MPa.

3. The method for preparing the co-doped IZO high-density ceramic material according to claim 1 or 2, characterized in that: The following steps are involved: Indium oxide powder, zinc oxide powder, hafnium oxide powder, yttrium oxide powder, a dispersant, a binder, a defoamer and water are mixed to prepare a slurry, and the obtained mixed slurry is ball-milled and granulated in sequence to obtain a mixed powder; The mixed powder is formed, and the obtained green body is sintered to obtain the co-doped IZO high-density ceramic material.

4. The preparation method according to claim 3, characterized in that: The sintering includes debinding sintering, pre-sintering and high-temperature sintering performed in sequence; the temperature of the debinding sintering is 600-750°C, and the insulation time is 5-10 hours; the pre-sintering is to increase the temperature from the debinding sintering temperature to 1500-1600°C; the temperature of the high-temperature sintering is 1300-1550°C, and the insulation time is 12-36 hours.

5. The preparation method according to claim 3, characterized in that: The rotation speed of the ball mill is 2000-3000rpm; the time of the ball mill is 1-8h; the ball-to-material ratio of the ball mill is 1:1-2; the ball milling beads used in the ball mill include three types of ball milling beads with diameters of 0.1mm, 0.3mm and 0.6mm respectively, and the weight ratio of the three types of ball milling beads is 1-5:1-5:1-5.

6. The preparation method according to claim 3, characterized in that: The forming process includes cold pressing forming process and cold isostatic pressing forming process performed in sequence; the pressure of the cold pressing forming process is 20-40MPa, and the holding time is 1-3min; the pressure of the cold isostatic pressing forming process is 250-300MPa, and the holding time is 20-60min.

7. The preparation method according to claim 3 or 5, characterized in that: The particle size D50 of the solid in the mixed slurry after ball milling is less than 0.2 μm, and the particle size D90 is less than 0.6 μm.

8. Use of the co-doped IZO high-density ceramic material according to claim 1 or 2 or the co-doped IZO high-density ceramic material prepared by the preparation method according to any one of claims 3 to 7 as a target material in the preparation of a transparent conductive oxide film.

9. A transparent conductive oxide film, characterized in that: The target material is sputter-coated on a substrate; The target material is the co-doped IZO high-density ceramic material according to claim 1 or 2 or the co-doped IZO high-density ceramic material prepared by the preparation method according to any one of claims 3 to 7.

10. The transparent conductive oxide film according to claim 9, characterized in that: The transparent conductive oxide film has a thickness of 50 to 150 nm and a mobility of 22 to 35 cm 2 V -1 S -1 The light transmittance is 83.2~89.6%.

Images