A method for preparing a high-density cerium-doped indium oxide target

Abstract

The application discloses a preparation method of a high-density cerium-doped indium oxide target material, which comprises the following steps: wet ball milling of raw material powder to obtain an ICO slurry, granulation of the ICO slurry to obtain ICO granulated powder, first compression molding of the ICO granulated powder to obtain an ICO blank, degreasing of the ICO blank, multiple compression molding of the ICO blank to obtain an ICO green body, and sintering of the ICO green body to obtain the cerium-doped indium oxide target material; the raw material powder is composed of In2O3 coarse powder, In2O3 fine powder and CeO2 powder; the particle size of the In2O3 coarse powder is 120-300 nm, and the particle size of the In2O3 fine powder is 20-50 nm. The application solves the bottleneck problem of the preparation technology of the high-density ICO target material, and the obtained ICO sintered target material has excellent properties of high density, low resistivity and high strength, and the process flow is simple, low in cost, green and pollution-free, and is suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of oxide ceramic target preparation technology, specifically relating to a method for preparing a high-density cerium-doped indium oxide target. Background Technology

[0002] In recent years, amorphous silicon / crystalline silicon heterojunction solar cells have become one of the most efficient solar cells in terms of photoelectric conversion, attracting widespread attention and research from the industry. The laboratory efficiency of heterojunction (HIT) solar cells has reached over 26%, with the average mass production efficiency of mainstream manufacturers reaching 23%. In terms of efficiency, HIT cells are a significant step up from PERC (Passivated Emitter and Rear Cell) technology. From a process flow perspective, the mainstream PERC technology requires 8-10 steps, while HIT technology only requires four: cleaning and texturing, amorphous silicon thin film deposition, TCO (Transparent Conductive Oxide) thin film preparation, and screen printing. While cleaning and texturing and screen printing are traditional silicon crystalline cell processes, HIT's unique process lies in the deposition of amorphous silicon thin films and TCO films. Indium tin oxide (ITO) thin films, as TCO electrode materials, are the most critical component of HIT battery structures. They are typically prepared using physical chemical vapor deposition (PVD), specifically DC magnetron sputtering, a mature process with good mass production capabilities. However, the PVD process is still limited by the inferior performance of ITO materials, primarily due to the absorption of free carriers in the near-infrared band, which restricts the spectral response of HIT batteries in the long-wavelength region. Reactive plasma deposition (RPD), on the other hand, uses evaporation to prepare ICO conductive films (cerium-doped indium oxide), which involves less bombardment of the silicon substrate, produces films with good conductivity, and can produce higher-efficiency HIT batteries. Therefore, the combination of RPD and ICO can produce higher-performance HIT battery materials, but its disadvantage lies in the higher cost of the equipment.

[0003] Due to a lack of fundamental research on ICO material preparation technology, the raw material for IWO thin films—IWO targets—mainly relies on imports, making it one of the "bottleneck" raw materials for my country's HIT battery industry. Currently, the bottlenecks in ICO target preparation technology mainly lie in the complexity of the preparation process and its high cost. Furthermore, purity control and the forming of large-size target blanks are also shortcomings in ICO target preparation technology. Compared to ITO targets, ICO target preparation requires more precise control. However, mature mass production technology for ICO targets is still lacking. Therefore, developing a simple, low-cost preparation technology for high-purity, high-density, and large-size ICO targets is urgently needed. Summary of the Invention

[0004] To address the challenges in fabricating high-density ICO targets for mass production in HIT batteries, this invention aims to provide a method for preparing high-density cerium-doped indium oxide (ICO) targets. The cerium-doped indium oxide target prepared by this invention exhibits high density, low resistivity, and high strength, and can be used as a target source for fabricating ICO thin films with excellent optoelectronic properties.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for preparing a high-density cerium-doped indium oxide target. The raw material powder is wet-milled to obtain an ICO slurry. The ICO slurry is granulated to obtain ICO granulated powder. The ICO granulated powder is first pressed to obtain an ICO blank. After degreasing the ICO blank, it is pressed multiple times to obtain an ICO green blank. The ICO green blank is sintered to obtain the cerium-doped indium oxide target.

[0007] The raw material powder is composed of coarse In2O3 powder, fine In2O3 powder, and CeO2 powder;

[0008] The particle size of the coarse In2O3 powder is 120-300 nm, preferably 120-200 nm, and the particle size of the fine In2O3 powder is 20-50 nm, preferably 20-40 nm. The amount of fine In2O3 powder added is 4.6-5 wt.% of the mass of the coarse In2O3 powder.

[0009] The preparation method of the present invention first adopts the "gap-filling strategy" to prepare ICO granulated powder by mixing In2O3 of different particle sizes and CeO2 of different particle sizes, and then using degreasing followed by multiple CIP to reduce the size of pores in the degreased green body. Finally, high-density cerium-doped indium oxide target material is obtained by sintering.

[0010] The inventors discovered that by controlling the particle size of coarse In2O3 powder, fine In2O3 powder, and the ratio of fine In2O3 powder to coarse In2O3 powder within the scope of this invention, the density of cerium-doped indium oxide target material can be significantly improved. The particle size distribution method in this invention, with a higher content of large-diameter powder than small-diameter powder, not only maximizes the gap-filling effect but also avoids the agglomeration of small-diameter powder, thus improving the sintering activity of the powder. If there is more small-diameter powder than large-diameter powder, it will cause severe agglomeration, reduce the ball milling dispersion effect, thereby weakening the sintering driving force and reducing the density of the ICO target material.

[0011] In a preferred embodiment, the amount of CeO2 powder added is 0.1-2.0% of the mass of the raw material powder, preferably 0.5-1.0%. The inventors have discovered that doping In2O3 with CeO2 utilizes the generated free electrons as charge carriers to improve the electrical performance of the ICO target. However, the amount of CeO2 powder added needs to be effectively controlled. If too little CeO2 powder is added, the number of free electrons will be insufficient, making it difficult to improve the electrical performance of the target. If too much CeO2 powder is added, Ce cannot be completely dissolved into the In2O3 lattice, resulting in excess CeO2 second phase in the target, which will inhibit the densification of the target and also reduce its electrical performance.

[0012] In a preferred embodiment, the CeO2 powder has a particle size of 50-200 nm, preferably 50-100 nm. The particle size of the CeO2 powder is smaller than that of coarse In2O3 powder and larger than that of fine In2O3 powder. In this invention, the optimal performance of the resulting ICO target material is achieved by controlling the particle size of the CeO2 powder to be between that of fine and coarse In2O3 powder. If the particle size is too small, the resulting agglomeration will lead to poor CeO2 dispersion uniformity. Conversely, if the particle size is too large, it will not be broken up during ball milling, also resulting in poor CeO2 dispersion uniformity. Both of these factors will ultimately affect the electrical properties of the ICO target material.

[0013] In a preferred embodiment, the average particle size of the fine In2O3 powder is [amount missing] times the average particle size of the coarse In2O3 powder. By controlling the average particle size within this preferred range, the final target material exhibits the highest density.

[0014] In a preferred embodiment, the ICO slurry comprises raw material powder, water, and a dispersant, wherein the dispersant is a polyacrylic acid dispersant;

[0015] The amount of the dispersant added is 0.1 to 0.5 wt.% of the raw material powder.

[0016] In a preferred embodiment, the solid content of the ICO slurry is 35-80 wt%, preferably 50-70 wt%.

[0017] In a preferred embodiment, the wet ball milling process is as follows: Raw material powder is placed in a ball mill using zirconia balls as grinding media, and water is added as the grinding medium, with a water-to-raw material powder mass ratio of 1:1 to 4. A dispersant is also added, and the mixture is ball-milled at a speed of 200 to 1000 r / min for 5 to 24 hours to obtain an ICO slurry. The inventors have found that the target material obtained using the above-described wet ball milling process exhibits the best performance.

[0018] In a preferred embodiment, the granulation method is spray granulation.

[0019] In a preferred embodiment, the average particle size of the ICO granulated powder is 30–80 μm, more preferably 40–60 μm.

[0020] In a preferred embodiment, the ICO granulated powder is loaded into a cold-press mold, and after vibration and vacuuming, it undergoes a first pressing and molding process. The vibration frequency is 30–100 Hz, and the vacuuming is performed to a vacuum degree of 10. -2 ~10 -1 Pa.

[0021] In a preferred embodiment, the first pressing is cold isostatic pressing, and the pressure of the cold isostatic pressing is controlled at 150-300 MPa, preferably 250-300 MPa, and the holding time is 5-60 min.

[0022] In a preferred embodiment, the degreasing is carried out in an air environment, the degreasing temperature is 500-700℃, the holding time is 30-240 min, and the heating rate is 10-60℃ / h.

[0023] A further preferred embodiment of the degreasing process is as follows: the temperature is increased to 100–150°C at a rate of 5–10°C / h, and held for 10–30 min; then increased to 280–320°C at a rate of 10–20°C / h, and held for 10–30 min; finally, the temperature is increased to 600–650°C at a rate of 20–30°C / h, and held for 60–240 min. Using this degreasing process, the resulting cerium-doped indium oxide target exhibits the best performance.

[0024] In a preferred embodiment, the multiple pressing molding process consists of three cold isostatic pressing molding processes. The pressure of the first cold isostatic pressing molding process is 250-300 MPa, and the holding time is 5-30 min. The pressure of the second cold isostatic pressing molding process is 180-200 MPa, and the holding time is 5-30 min. The pressure of the third cold isostatic pressing molding process is 100-150 MPa, and the holding time is 5-30 min.

[0025] In this invention, after obtaining the green body by cold isostatic pressing, degreasing is performed. After degreasing, multiple cold isostatic pressing is performed, which can significantly reduce the size of the pores in the green body after degreasing, thereby improving the density of the target material. In the actual exploration process, the inventors also tried to perform multiple cold isostatic pressing and then degreasing, but the densification effect was far inferior to that of this invention.

[0026] In a preferred embodiment, the ICO green blank is placed in a sintering furnace and subjected to oxygen replacement before sintering. The oxygen replacement process involves first evacuating the furnace to a vacuum level of 10. -2 ~10 -1 Pa, then oxygen is introduced until the pressure reaches 10. 2 ~10 3 Maintain the pressure at 10 Pa for 10–30 minutes, and repeat the vacuuming and oxygen-introduction process three times.

[0027] The inventors discovered that during oxygen replacement, it is necessary to maintain the oxygen supply for 10 to 30 minutes after each oxygen introduction in order to fully eliminate the non-oxidizing gases adsorbed in the pores of the ICO blank, thereby avoiding the non-oxidizing gases from producing a reverse densification effect.

[0028] In a preferred embodiment, the sintering is performed under atmospheric pressure in an oxygen atmosphere, with a sintering temperature of 1500℃-1600℃, a sintering time of 2h-10h, and a heating rate controlled at 60℃ / h-300℃ / h.

[0029] The inventors discovered that by reducing the size of pores in the green body through multiple pressing and molding after degreasing in the early stage, and by fully replacing the oxygen before sintering to remove the non-oxidizing gases adsorbed in the pores of the green body, a high-density cerium-doped indium oxide target can be obtained in just one sintering step.

[0030] The cerium-doped indium oxide target prepared by this invention has In₂O₃ as its main phase, a relative density ≥99.0%, and a resistivity ≤2.5×10⁻⁶. -4 Ω·cm, flexural strength ≥150MPa.

[0031] Principles and advantages

[0032] This invention utilizes a "gap-filling strategy" to mix In2O3 powder and CeO2 powder of two particle sizes, followed by wet ball milling and spray drying to granulate ICO powder. The granulated powder is then loaded into a cold-pressing mold, subjected to vibration and vacuuming, and then cold isostatic pressing to obtain an ICO green body. The ICO green body is then degreased in air and subjected to three CIP treatments to obtain the ICO raw green body. Finally, the ICO raw green body undergoes three vacuum + oxygen replacement treatments to eliminate non-oxidizing gases adsorbed in the pores as much as possible, and then atmospheric pressure sintering is completed in a pure oxygen atmosphere to obtain the novel indium cerium oxide (ICO) target material.

[0033] The specific advantages are as follows:

[0034] (1) A high-density ICO green body is obtained by means of a "gap-filling strategy". This invention uses large-particle-size In2O3 powder with an initial particle size of 120-300 nm and small-particle-size In2O3 powder with an initial particle size of 20-50 nm (the average particle size of the small-particle-size In2O3 is based on the large-particle-size In2O3 powder). (Calculated by multiples), the original particle size of CeO2 powder is 50-200nm; the mass of small-particle-size In2O3 powder is controlled at 4.8±0.2wt.% of the mass of large-particle-size In2O3 powder.

[0035] (2) The present invention performs three CIP treatments on the degreased green body, which can maximize the compression of pores in the green body. The specific method is as follows: the pressure of the first CIP is controlled at 250-300 MPa and held for 10 min; the pressure of the second CIP is controlled at 180-200 MPa and held for 10 min; the pressure of the third CIP is controlled at 100-150 MPa and held for 10 min.

[0036] (3) Before sintering, the green body undergoes three "vacuum + oxygen replacement treatments" to eliminate non-oxidizing gases adsorbed in the pores. The ICO green body, after degreasing and undergoing three CIP treatments, is placed in a vacuum-capable atmosphere sintering furnace for oxygen replacement. The ICO green body is then subjected to vacuum treatment, with the vacuum level controlled at 10. -2 ~10 -1 Between 10 Pa, then pure oxygen gas is introduced, with the pressure controlled at 10. 2 ~10 3 The pressure is maintained between Pa and 10-30 min; this process is repeated 3 times to complete oxygen replacement, eliminate non-oxidizing gases adsorbed in the pores to the maximum extent, and clear obstacles for densification.

[0037] In summary, this invention utilizes a "gap-filling strategy" combined with "oxygen replacement" and "multiple CIP" to specially treat the target blank, reducing the pore size and internal adsorption of non-oxidizing gases. This results in the preparation of high-density, low-resistivity, and high-strength ICO sintered targets, meeting the requirements of high-performance HIT batteries for ICO materials. Therefore, this invention provides a mass-producible method for preparing ICO sintered targets. The technology is simple, efficient, low-cost, and low-pollution, possessing significant practical value. Attached Figure Description

[0038] Figure 1 This is a process flow diagram for preparing ICO target materials according to the present invention;

[0039] Figure 2These are SEM images of indium oxide powder with different particle sizes; Figure (a) shows the particle size of coarse In2O3 powder, with an original particle size of 120–300 nm; Figure (b) shows the particle size of fine In2O3 powder, with an original particle size of 20–50 nm.

[0040] Figure 3 These are SEM images of the fracture surfaces of ICO targets with different cerium contents; among them Figure 3 (a) is a SEM image of the fracture surface of the ICO target obtained in Example 1 when the cerium content is 0 wt%; Figure 3 (b) is a SEM image of the fracture surface of the ICO target obtained in Example 2 when the cerium content was 0.5 wt%; Figure 3 (c) is a SEM image of the fracture surface of the ICO target obtained in Example 3 when the cerium content was 1.0 wt%; Figure 3 (d) is a SEM image of the fracture surface of the ICO target obtained in Example 4 when the cerium content was 2.0 wt%.

[0041] Figure 4 These are EPMA images of ICO targets with different cerium contents. Figure 4 (a) is the EPMA diagram of the ICO target obtained in Example 1 when the cerium content was 0 wt%; Figure 4 (b) is the EPMA image of the ICO target obtained in Example 2 when the cerium content was 0.5 wt%; Figure 4 (c) is the EPMA image of the ICO target obtained in Example 3 when the cerium content was 1.0 wt%; Figure 4 d) is the EPMA diagram of the ICO target material obtained in Example 4 when the cerium content was 2.0 wt%. Detailed Implementation

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0043] Example 1

[0044] In a mass percentage ratio of 4.8% to 95.2%, In2O3(1) powder (original particle size of 20nm, purity of 4N5) and In2O3(2) powder (original particle size of 120nm, purity of 4N) were loaded into a high-energy ball mill. Pure water and dispersant were added as required, and then wet ball milling was performed to obtain a slurry. Ball milling process: Zirconia balls were used, with a powder-to-ball mass ratio of 1:4; the grinding medium was deionized water, and the dispersant was a polyacrylic acid dispersant, wherein the mass ratio of deionized water to powder was 1:1, and the content of polyacrylic acid dispersant accounted for 0.5wt.% of the powder mass; the high-speed ball milling speed was 500r / min, and the ball milling time was 300min.

[0045] Subsequently, granulation was performed using a spray method to obtain granulated powder with an average particle size of 40–60 μm for later use. The spray-granulated powder was then loaded into a cold-pressing mold and subjected to 60 Hz vibration and vacuuming (vacuum degree 10). -2 After treatment with Pa), the blank is directly cold isostatically pressed to obtain the blank. The cold isostatic pressing process is as follows: the CIP pressure is controlled at 250 MPa, and the pressure is held for 10 minutes.

[0046] The blank obtained by cold isostatic pressing is placed in air for degreasing. The degreasing process is as follows: the temperature is increased to 125°C at a heating rate of 5°C / h and held for 20 min; then the temperature is increased to 300°C at a heating rate of 10°C / h and held for 20 min; finally, the temperature is increased to 600°C at a heating rate of 20°C / h and held for 200 min.

[0047] The green blank is then subjected to three CIP processes. The first CIP pressure is controlled at 250 MPa and held for 10 min; the second CIP pressure is controlled at 180 MPa and held for 10 min; and the third CIP pressure is controlled at 100 MPa and held for 10 min.

[0048] The green blank is placed in a vacuum-capable atmosphere sintering furnace for oxygen replacement, and then subjected to vacuum treatment with the vacuum level controlled at 10. -2 ~10 -1 Between 10 Pa, then pure oxygen gas is introduced, with the pressure controlled at 10. 2 ~10 3 The pressure should be maintained between 10 Pa and 15 min; this process should be repeated 3 times to complete the oxygen replacement.

[0049] After oxygen replacement, the resulting green body is sintered in a pure oxygen atmosphere at 1560℃ for 5 hours under normal pressure, with the heating rate controlled at 120℃ / h, to obtain the sintered target material.

[0050] Following the above process, the resulting target material has a good appearance and is black in color. The density of the sintered target material, measured using Archimedes' displacement method, is 7.138 g·cm³. -3 Its relative density was calculated to be 99.76% (theoretical density is 7.155 g·cm³). -3 Its fracture surface SEM image is as follows: Figure 3 (a) No large pores were observed, indicating that the target material has good density. Figure 4 (a) is a graph showing the Ce element content distribution in the target material measured using EPMA. Its flexural strength, measured using the three-point bending method, is 125 MPa, and its resistivity, measured using the four-point probe method, is 2.27 × 10⁻⁶. -4 Ω·cm.

[0051] Example 2

[0052] According to the mass percentage ratio of 4.78%: 94.72%: 0.50%, In2O3(1) powder (original particle size of 20nm, purity of 4N5), In2O3(2) powder (original particle size of 120nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill. Wet ball milling, granulation, CIP molding, degreasing + CIP, vacuum + oxygen replacement and other operations were completed according to Example 1. Then, the obtained green body was sintered in a pure oxygen atmosphere at 1500℃ under normal pressure for 5h, and the heating rate was controlled at 120℃ / h to obtain the sintered target material and the ICO target material.

[0053] The ICO target material obtained using the above process has a good appearance and is black in color. The density of the sintered target material, measured using Archimedes' displacement method, is 7.127 g·cm³. -3 Its relative density was calculated to be 99.60% (theoretical density is 7.156 g·cm³). -3 Its fracture surface SEM image is as follows: Figure 3 (b) No large pores were observed, indicating that the target material has good density. Figure 4 (b) shows the Ce element content distribution in the target material measured by EPMA. The flexural strength was measured to be 200 MPa using the three-point bending method, and the resistivity was measured to be 2.10 × 10⁻⁶ MPa using the four-point probe method. -4 Ω·cm.

[0054] Example 3

[0055] According to the mass percentage ratio of 4.75%: 94.25%: 1.00%, In2O3(1) powder (original particle size of 20nm, purity of 4N5), In2O3(2) powder (original particle size of 120nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill, and wet ball milling, granulation, CIP molding, degreasing + CIP, vacuum + oxygen replacement and sintering were completed according to Example 2 to obtain ICO target material.

[0056] The ICO target material obtained using the above process has a good appearance and is black in color. The density of the sintered target material, measured using Archimedes' displacement method, is 7.113 g·cm³. -3 Its relative density was calculated to be 99.40% (theoretical density is 7.156 g·cm³). -3 Its fracture surface SEM image is as follows: Figure 3 (c) No large pores were observed, indicating that the target material has good density. Figure 4 (c) is a Ce element content distribution diagram in the target material measured by EPMA. Its flexural strength was measured to be 180 MPa using the three-point bending method, and its resistivity was measured to be 1.87 × 10⁻⁶ using the four-point probe method. -4 Ω·cm.

[0057] Example 4

[0058] According to the mass percentage ratio of 4.75%: 94.25%: 2.00%, In2O3(1) powder (original particle size of 20nm, purity of 4N5), In2O3(2) powder (original particle size of 120nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill, and wet ball milling, granulation, CIP molding, degreasing + CIP, vacuum + oxygen replacement and sintering were completed according to Example 2 to obtain ICO target material.

[0059] The ICO target material obtained using the above process has a good appearance and is black in color. The density of the sintered target material, measured using Archimedes' displacement method, is 7.100 g·cm³. -3 Its relative density was calculated to be 99.22% (theoretical density is 7.156 g·cm³). -3 Its fracture surface SEM image is as follows: Figure 3 (d) No large pores were observed, indicating that the target material has good density. Figure 4 (d) shows the Ce element content distribution in the target material measured by EPMA. Its flexural strength, measured using the three-point bending method, is 165 MPa, and its resistivity, measured using the four-point probe method, is 2.00 × 10⁻⁶. -4 Ω·cm.

[0060] Comparative Example 1

[0061] In a mass percentage ratio of 98.00%:2.00%, In2O3(2) powder (original particle size of 120nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill. Wet ball milling, granulation, CIP molding, degreasing + CIP, vacuum + oxygen replacement and sintering were completed according to Example 4 to obtain ICO target material.

[0062] The ICO target material obtained using the above process has a good appearance and a dark green color. The density of the sintered target material, measured using Archimedes' displacement method, is 7.00 g·cm³. -3 Its relative density was calculated to be 97.82% (theoretical density is 7.156 g·cm³). -3 Its flexural strength was measured to be 105 MPa using the three-point bending test method, and its resistivity was measured to be 3.12 × 10⁻⁶ MPa using the four-point probe method. -4 Ω·cm.

[0063] Comparative Example 2

[0064] According to the mass percentage ratio of 4.75%: 94.25%: 2.00%, In2O3(1) powder (original particle size of 20nm, purity of 4N5), In2O3(2) powder (original particle size of 120nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill. Wet ball milling, granulation and CIP molding were completed according to Example 4 to obtain ICO green body. Then, after degreasing, vacuum + oxygen replacement and sintering, ICO target material was obtained.

[0065] The ICO target material obtained using the above process has a good appearance and a dark green color. The density of the sintered target material, measured using Archimedes' displacement method, is 7.03 g·cm³. -3 Its relative density was calculated to be 98.24% (theoretical density is 7.156 g·cm³). -3 Its flexural strength was measured to be 120 MPa using the three-point bending test method, and its resistivity was measured to be 2.80 × 10⁻⁶ MPa using the four-point probe method. -4 Ω·cm.

[0066] Comparative Example 3

[0067] According to the mass percentage ratio of 4.75%: 94.25%: 2.00%, In2O3(1) powder (original particle size of 20nm, purity of 4N5), In2O3(2) powder (original particle size of 120nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill. Wet ball milling, granulation, CIP molding and degreasing + CIP were completed according to Example 4 to obtain ICO green blank, which was then placed in a sintering furnace for sintering under a pure oxygen atmosphere to obtain ICO target material.

[0068] The ICO target material obtained using the above process has a good appearance and a dark green color. The density of the sintered target material, measured using Archimedes' displacement method, is 6.98 g·cm³. -3 Its relative density was calculated to be 97.54% (theoretical density is 7.156 g·cm³). -3 Its flexural strength was measured to be 114 MPa using the three-point bending test method, and its resistivity was measured to be 3.30 × 10⁻⁶ MPa using the four-point probe method. -4 Ω·cm.

[0069] Comparative Example 4

[0070] According to the mass percentage ratio of 49.0%:49.0%:2.00%, In2O3(1) powder (original particle size of 20nm, purity of 4N5), In2O3(2) powder (original particle size of 120nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill and wet ball milling, granulation, CIP molding, degreasing + CIP, vacuum + oxygen replacement and sintering were completed according to Example 4 to obtain ICO target material.

[0071] The ICO target material obtained using the above process has a good appearance and a dark green color. The density of the sintered target material, measured using Archimedes' displacement method, is 6.79 g·cm³. -3 Its relative density was calculated to be 94.89% (theoretical density is 7.156 g·cm³). -3 Its flexural strength was measured to be 82 MPa using the three-point bending method, and its resistivity was measured to be 7.60 × 10⁻⁶ MPa using the four-point probe method. -4 Ω·cm.

[0072] Comparative Example 5

[0073] In a mass percentage ratio of 98.0% to 2.00%, In2O3(1) powder (original particle size of 20nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill. Wet ball milling, granulation, CIP molding, degreasing + CIP, vacuum + oxygen replacement and sintering were completed according to Example 4 to obtain ICO target material.

[0074] The ICO target material obtained using the above process has a good appearance and is green in color. The density of the sintered target material, measured using Archimedes' displacement method, is 5.98 g·cm³. -3 Its relative density was calculated to be 83.57% (theoretical density is 7.156 g·cm³). -3 Its flexural strength was measured to be 67 MPa using the three-point bending test method, and its resistivity was measured to be 2.67 × 10⁻⁶ MPa using the four-point probe method. -3 Ω·cm.

[0075] Comparative Example 6

[0076] According to the mass percentage ratio of 4.75%:94.25%:2.00%, In2O3(1) powder (original particle size of 20nm, purity of 4N5), In2O3(2) powder (original particle size of 120nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill. After wet ball milling, granulation, CIP molding, degreasing and CIP as in Example 2, an ICO green blank was obtained. The green blank was placed in a vacuum atmosphere sintering furnace for oxygen replacement and vacuum treatment, with the vacuum degree controlled at 10. -2~10 -1 Between 10 Pa, then pure oxygen gas is introduced, with the pressure controlled at 10. 2 ~10 3 Between Pa, when the oxygen pressure reaches the required level, a vacuum is immediately drawn; after repeating this process 3 times, the resulting green body is sintered in a pure oxygen atmosphere at 1560℃ for 5 hours under normal pressure, with the heating rate controlled at 120℃ / h, thus obtaining the sintered target material.

[0077] The ICO target material obtained using the above process has a good appearance and a dark green color. The density of the sintered target material, measured using Archimedes' displacement method, is 7.00 g·cm³. -3 Its relative density was calculated to be 97.82% (theoretical density is 7.156 g·cm³). -3 Its flexural strength was measured to be 123 MPa using the three-point bending test method, and its resistivity was measured to be 3.20 × 10⁻⁶ MPa using the four-point probe method. -4 Ω·cm.

[0078] Comparative Example 7

[0079] According to the mass percentage ratio of 4.75%: 94.25%: 2.00%, In2O3(1) powder (original particle size of 20nm, purity of 4N5), In2O3(2) powder (original particle size of 120nm, purity of 4N5) and CeO2 powder (original particle size of 50nm, purity of 4N) were loaded into a high-energy ball mill and wet ball milling and granulation were completed according to Example 2 to obtain ICO granulated powder.

[0080] The spray-granulated powder is loaded into a cold-press mold, subjected to 60Hz vibration and vacuuming (vacuum degree 10). -2 After treatment with Pa), the blank is directly CIP formed to obtain a green body, which is then subjected to two more CIP treatments. The three-stage CIP process is as follows: the first CIP pressure is controlled at 250 MPa and held for 10 min; the second CIP pressure is controlled at 180 MPa and held for 10 min; the third CIP pressure is controlled at 100 MPa and held for 10 min. The green body obtained after three CIPs is placed in air to complete degreasing, thus obtaining the ICO green body. The green body is placed in a vacuum atmosphere sintering furnace to complete oxygen replacement and sintering according to Example 2, thus obtaining the ICO sintered target material.

[0081] The ICO target material obtained using the above process has a good appearance and a dark green color. The density of the sintered target material, measured using Archimedes' displacement method, is 6.90 g·cm³. -3 Its relative density was calculated to be 96.42% (theoretical density is 7.156 g·cm³). -3 Its flexural strength was measured to be 110 MPa using the three-point bending test method, and its resistivity was measured to be 3.54 × 10⁻⁶ MPa using the four-point probe method. -4Ω·cm.

[0082] Table 1 shows the density, flexural strength, and resistivity of the ICO target materials in the examples.

[0083]

[0084]

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of producing a high-density cerium-doped indium oxide target material, characterized by: The raw material powder is wet ball-milled to obtain an ICO slurry, the ICO slurry is granulated to obtain an ICO granulated powder, the ICO granulated powder is first-pressed to obtain an ICO green body, the ICO green body is debinded and then subjected to multiple cold isostatic pressing treatments to obtain an ICO green compact, and the ICO green compact is placed in a sintering furnace, subjected to oxygen replacement and then sintered to obtain a cerium-doped indium oxide target; The raw material powder is composed of In2O3 coarse powder, In2O3 fine powder and CeO2 powder; The particle size of the In2O3 coarse powder is 120-300 nm, the particle size of the In2O3 fine powder is 20-50 nm, and the addition amount of the In2O3 fine powder is 4.6-5 wt.% of the mass of the In2O3 coarse powder; The particle size of the CeO2 powder is 50-200 nm, which is smaller than that of the In2O3 coarse powder and larger than that of the In2O3 fine powder; The addition amount of the CeO2 powder is 0.1-2.0% of the mass of the raw material powder; The oxygen replacement process is: first vacuum to a vacuum degree of 10 -2 ~10 -1 Pa, then pass in oxygen to a pressure of 10 2 ~10 3 Pa, and keep for 10-30 min, repeat the vacuum-passing in oxygen 3 times; The sintering is carried out under an oxygen atmosphere at a temperature of 1500-1600℃ for 2-10 h at a heating rate of 60-300℃ / h.

2. The method of claim 1, wherein the high-density cerium-doped indium oxide target is prepared by the steps of: The ICO slurry contains the raw material powder, water and a dispersant, and the dispersant is a polyacrylic dispersant; ​ The addition amount of the dispersant is 0.1-0.5 wt.% of the mass of the raw material powder. The solid content of the ICO slurry is 35-80 wt.%.

3. The method of claim 1 or 2, wherein the method further comprises: The wet ball-milling process is as follows: the raw material powder is placed in a ball mill, zirconia balls are used as grinding balls, water is added as a grinding medium, the mass ratio of water to the raw material powder is 1:1-4, a dispersant is added, and the ball-milling speed is 200-1000 r / min for 5-24 h to obtain the ICO slurry. ​ 4. The method of claim 1, wherein the method further comprises: The granulation is carried out by spray granulation. ​ The average particle size of the ICO granulated powder is 30-80 μm.

5. The method of claim 1, wherein the method further comprises: The ICO granulated powder is loaded into a cold press mold, and after vibration and vacuum operation, the first compression molding is performed, the frequency of the vibration is 30-100 Hz, and the vacuum is extracted to a vacuum degree of 10 -2 ~10 -1 Pa; ​ The first pressing is cold isostatic pressing, and the pressure is controlled at 150-300 MPa for 5-60 min.

6. The method of claim 1, wherein the method further comprises: The debinding is carried out in an air environment at a temperature of 500-700℃ for 30-240 min at a heating rate of 10-60℃ / h. ​ 7. The method of claim 1, wherein the method further comprises: The multiple cold isostatic pressing treatments are 3 times of cold isostatic pressing, the first cold isostatic pressing treatment is carried out at a pressure of 250-300 MPa for 5-30 min, the second cold isostatic pressing treatment is carried out at a pressure of 180-200 MPa for 5-30 min, and the third cold isostatic pressing treatment is carried out at a pressure of 100-150 MPa for 5-30 min. ​

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