High-mobility praseodymium-neodymium co-doped indium zinc oxide sputtering target material and preparation method thereof

Abstract

The invention discloses a high-mobility praseodymium-neodymium co-doped indium zinc oxide sputtering target material and a preparation method thereof, and belongs to the field of transparent conductive oxide materials. The target material is composed of 85.0 wt% to 95.0 wt% of indium oxide, 5.0 wt% to 15.0 wt% of zinc oxide and 0.3 wt% to 0.6 wt% of praseodymium and neodymium co-doped oxide. The preparation method comprises the following steps: performing multi-temperature gradient air calcination compounding on indium oxide powder, and performing carbon-buried atmosphere calcination on zinc oxide; performing four-section type rotating speed grinding by adopting a double-dispersant synergistic dispersion system to obtain uniform slurry; and finally, carrying out spray drying, forming and normal-pressure sintering in a specific atmosphere system. Through component and process innovation, the problems that a traditional IZO target material is prone to element volatilization, low in density and insufficient in migration rate are solved, the relative density of the obtained target material is larger than or equal to 99%, the grain size is uniform, the migration rate of a thin film used for sputtering reaches up to 68 cm < 2 > / V.s, the resistivity is not higher than 4 * 10 <-4 > omega.cm, the comprehensive performance is remarkably superior to that of a conventional IZO and ITO target material, and the target material is suitable for large-scale production. The method is especially suitable for high-performance perovskite solar cell transparent electrodes.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of transparent conductive oxide (TCO) sputtering target preparation, in particular to a high-mobility praseodymium (Pr) and neodymium (Nd) co-doped indium zinc oxide (IZO) sputtering target for high-efficiency perovskite solar cells and a normal-pressure sintering preparation method thereof. BACKGROUND

[0002] Transparent conductive oxide (TCO) thin films are the core electrode materials of photovoltaic devices such as solar cells and flat panel displays. Among them, indium tin oxide (ITO) is widely used due to its excellent comprehensive performance. However, with the development of perovskite solar cells towards high efficiency and low cost industrialization, the performance requirements for transparent electrodes are almost stringent: the resistivity needs to be lower than 5×10 -4 Ω·cm to reduce the series resistance, the carrier mobility should be higher than 50 cm 2 / V·s to reduce scattering loss, and the visible light region (550 nm) transmittance should be more than 83% to ensure the photon capture efficiency.

[0003] Traditional ITO targets face severe challenges: first, tin (Sn) elements are prone to segregation during sintering and use, resulting in uneven target resistivity and limited mobility of 40-45 cm 2 / V·s; second, the metal indium (In) resource is scarce and expensive, which restricts its large-scale application.

[0004] Indium zinc oxide (IZO, usually In2O3:ZnO≈90:10) target is considered as an ideal alternative, but its industrial application still has the following technical bottlenecks: (1) High-temperature physical instability: In2O3 is prone to decomposition to produce low-valence oxides or indium vapor at high temperature sintering above 1300℃, and release oxygen, causing pore defects in the target and more than 1.5% loss of indium; ZnO is prone to volatilization and segregation at high temperature (steam pressure reaches 10 -3 atm at 1300℃), with zinc loss up to 3%, and about 100nm of zinc-rich phase formed at the grain boundary, which becomes a carrier scattering center, seriously degrading the mobility; (2) Densification and conductivity contradiction: In order to promote the densification of IZO target sintering, Bi2O3 and other sintering aids are often introduced, but these impurity phases will introduce defects, significantly reducing the intrinsic conductivity of the material; (3) Powder dispersion and composition uniformity problem: due to the large density difference between In2O3 (density 7.14 g / cm 3 ) and ZnO (density 5.6 g / cm 3There is a significant density difference between the powders, and it is difficult to solve the problems of sedimentation and agglomeration at the same time by using a single dispersant system, resulting in low grinding efficiency and macroscopic and microscopic segregation of indium and zinc components in the final target material.

[0005] Therefore, developing a preparation method of an IZO sputtering target material without introducing impurity sintering aids, capable of inhibiting element volatilization and segregation, achieving ultra-high density and composition uniformity, and finally obtaining a high-performance IZO sputtering target material with high mobility and low resistivity has become a key technical problem to be solved in the field. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a high-mobility praseodymium-neodymium co-doped indium zinc oxide sputtering target material and a preparation method thereof. The present application adopts three technical innovations, i.e., powder calcination and synergistic treatment, double dispersant synergistic dispersion system construction, and lanthanide co-doping band-grain synergistic mechanism optimization, to prepare a high-performance indium zinc oxide (IZO) sputtering target material by using a normal-pressure sintering method. The IZO thin film obtained by sputtering has better performance than traditional ITO thin films and conventional IZO thin films, and has high conductivity and high electron mobility, which meets the practical application requirements of high-performance perovskite solar cells.

[0007] To achieve the above-mentioned purpose, the present application adopts the following specific solutions: In one aspect, the present application provides a high-mobility praseodymium-neodymium co-doped indium zinc oxide sputtering target material, comprising a main element powder and a lanthanide-doped oxide, wherein the main element powder comprises 85.0-95.0wt% of indium oxide and 5.0-15.0wt% of zinc oxide according to the weight percentage. The addition amount of the lanthanide-doped oxide accounts for 0.3-0.6wt% of the total mass of the main element powder, the lanthanide-doped oxide comprises praseodymium oxide and neodymium oxide, and the praseodymium oxide accounts for 30%~85% of the total mass of the lanthanide-doped oxide.

[0008] Further, the relative density of the target material is not less than 99%, the grain size is 5-7μm, and the resistivity is not higher than 4.0×10 -4 Ω·cm.

[0009] Further, the particle size of the lanthanide-doped oxide is ≤200nm.

[0010] In another aspect, the present application provides a method for preparing a high-mobility praseodymium-neodymium co-doped indium zinc oxide sputtering target material, comprising the following steps: Step (1), powder calcination The indium oxide powder is divided into multiple groups and subjected to air atmosphere calcination at 600–1200℃ for 2-4h, and then used after compounding; The zinc oxide powder is subjected to carbon-embedded atmosphere calcination at 800–1000℃ for 2-4h; Step (2), mixing and grinding (2-1), mixing the calcined indium oxide powder, zinc oxide powder and lanthanide-doped oxide powder with a first dispersant and pure water, and performing high-speed shearing dispersion to obtain a first dispersion slurry, the solid content of the first dispersion slurry being 55-65wt%; (2-2), performing ultrasonic treatment on the first dispersion slurry; (2-3), performing grinding treatment on the first dispersion slurry subjected to ultrasonic treatment, and adding a second dispersant, a binder and a defoaming agent during the grinding process; The grinding treatment adopts four-stage speed control: Stage one: grinding at a speed of 550-650rpm for 0.1-2h; Stage two: grinding at a speed of 450-550rpm for 2-8h; Stage three: grinding at a speed of 350-450rpm for 8-18h; Stage four: grinding at a speed of 250-350rpm for 18-24h; The D90 of the slurry after grinding is controlled to be ≤0.5μm, and the pH is adjusted to 6.8-7.2 to obtain a second dispersion slurry; Step (3), granulation and forming The obtained second dispersion slurry is spray-dried to obtain a powder, and the powder is sequentially subjected to dry pressing and cold isostatic pressing to obtain a green body; Step (4), normal-pressure sintering The sintering step is performed according to the following schedule: Debinding stage: under a nitrogen atmosphere, heating from room temperature to 600℃ at a heating rate of 0.5℃ / min; Sintering stage: under a pure oxygen atmosphere, first heating from 600℃ to 1200℃ at a heating rate of 1℃ / min, and then heating from 1200℃ to 1450℃ at a heating rate of 0.1℃ / min; Cooling stage: first cooling from 1450℃ to 1000℃ at a cooling rate of 0.5℃ / min under a pure oxygen atmosphere, and then cooling from 1000℃ to room temperature at a cooling rate of 0.5℃ / min under an air atmosphere; Finally, the sputtering target material is obtained.

[0011] Further, in the step (2-1), the first dispersant is added in an amount of 0.5-1.5wt% of the total mass of the main unit powder and the lanthanide-doped oxide. The first dispersant is selected from one or more of ammonium citrate, polyammonium aspartate, polyammonium methacrylate, hydrolyzed polyacrylonitrile ammonium salt, hyperbranched polyglycerol ether and sulfonated polystyrene ammonium salt.

[0012] Further, in the step (2-3), the second dispersant is added in an amount of 0.5-1.5wt% of the total mass of the main unit powder and the lanthanum-doped oxide; The antifoaming agent is added in an amount of 0.05-0.1wt% of the total mass of the first dispersion slurry; The binder is added in an amount of 1.5-3.0wt% of the total mass of the main unit powder and the lanthanum-doped oxide.

[0013] Further, in the step (2-3), the second dispersant is selected from one or more of ammonium polyacrylate, sodium gluconate, ethylenediamine tetraacetate ammonium, ammonium tartrate, ammonium lauryl sulfate, diethylene triamine pentaacetate ammonium; The antifoaming agent is polydimethylsiloxane; The binder is one or more of polyvinyl alcohol, polyethylene glycol-1000, polymethacrylic acid, carboxymethyl cellulose, etc.

[0014] Further, in the step (2-3), the second dispersant and the antifoaming agent are uniformly added in the grinding process of the stages one to four; and the binder is added in the last 1-2 hours of the stage four.

[0015] Further, in the step (3), after the powder is dry-pressed at 60MPa, cold isostatic pressing is performed at 230MPa, and the obtained green body density is greater than 60%.

[0016] Further, in the step (1), the indium oxide powder is divided into four groups according to the mass ratio of (1~2):(2~4):(3~5):(2~4), and calcination is performed at a calcination temperature of 600℃, 800℃, 1000℃ and 1200℃, respectively.

[0017] Beneficial effects: (1) Powder calcination and synergistic treatment: the present application adopts a gradient temperature calcination and compounding process for In2O3, and the powders calcined at different temperatures have different lattice distortion energy and surface energy. After compounding, the oxygen defect distribution can be optimized at the atomic scale, the overall sintering activation energy is reduced, and thus the required temperature and time are reduced in subsequent sintering, which indirectly suppresses the high-temperature decomposition and volatilization of In2O3. The ZnO is calcined in a carbon-embedded atmosphere to create a weak reducing environment, effectively inhibiting the decomposition and volatilization of ZnO at high temperatures, reducing the loss of Zn to a very low level, and stabilizing the appropriate oxygen vacancies to ensure the carrier concentration. The synergy of the two pretreatment methods solves the core problems of high-temperature element volatilization loss and composition segregation from the source.

[0018] (2) Dual dispersant synergistic dispersion system: In view of the problem of sedimentation and agglomeration caused by the large density difference between In2O3 and ZnO, the application innovatively adopts a stepwise adsorption dispersion mechanism of synergistic action of a first dispersant and a second dispersant. The first dispersant (such as ammonium citrate) is preferentially added, and its small molecular structure can quickly adsorb on the surface of the powder, occupy the coordination sites of In 3+ / Zn 2+ , form a monolayer, and prevent hydroxyl bridging agglomeration between particles through electrostatic repulsion. The second dispersant (such as ammonium polyacrylate) is then added, and its long molecular chain can be bridged with the first dispersant molecular layer through hydrogen bonds, thereby avoiding the problem of being "pinned" and cut off by directly coordinating with metal ions, and can fully stretch in the slurry to form a three-dimensional steric hindrance effect. The synergism of the two dispersants realizes the perfect combination of electrostatic stabilization and steric hindrance stabilization, greatly improves the stability of the slurry, solves the problems of sedimentation and composition segregation caused by density difference, and lays a foundation for obtaining microscopically extremely uniform target materials.

[0019] (3) Lanthanide co-doping energy band-grain boundary synergistic mechanism: The application discards single doping and creatively adopts Pr / Nd co-doping strategy, and the two play different roles in the IZO lattice to realize "division optimization": The role of Pr doping: Pr ions mainly enter the indium oxide lattice to replace In sites. Since lanthanide elements have variable valence characteristics, Pr doping can effectively provide free electrons, significantly increasing the carrier concentration of the material; The role of Nd doping: The ionic radius of Nd ions is closer to In, but its segregation tendency is stronger, and it tends to enrich at the grain boundaries. The segregation of Nd at the grain boundaries can effectively pin the grain boundaries, inhibit abnormal grain growth, passivate defect states at the grain boundaries, and reduce the grain boundary barrier, thereby greatly reducing the scattering of carriers at the grain boundaries; Synergistic effect: Pr is responsible for "energy supply" (providing carriers), and Nd is responsible for "escort" (reducing scattering). This synergistic mechanism breaks the theoretical bottleneck of IZO material mobility, and the electronic mobility of the finally prepared IZO film is as high as 68 cm 2 / V·s, which is much higher than that of conventional IZO (~40 cm 2 / V·s) and ITO (~32 cm 2 / V·s) films.

[0020] (4) The four-stage grinding and precision sintering system: the target material performance is optimized by the synergy of the four-stage grinding and precision sintering system. The four-stage grinding uses high, medium and low speeds in turn, gradually realizes hard agglomeration crushing, particle refinement, anti-agglomeration fine grinding and stress homogenization, and obtains high-stability slurry with uniform dispersion and controllable particle size (D90≤0.5 μm). Nitrogen is used for degreasing in the sintering stage to ensure that there is no residual organic matter; pure oxygen atmosphere combined with slow heating effectively inhibits the high-temperature volatilization and decomposition of indium and zinc elements; programmed cooling avoids product cracking and stabilizes the oxygen vacancy concentration. The process finally prepares high-performance target material with a relative density of up to 99.5%, small and uniform crystal grains, and low resistivity. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0022] It should be noted that the "total mass of the powder" described below refers to the sum of the mass of the main base powder and the lanthanide-doped oxide unless otherwise specified.

[0023] The present application provides a high-mobility praseodymium-neodymium co-doped indium zinc oxide sputtering target material, comprising a main base powder and a lanthanide-doped oxide, wherein the main base powder comprises 85.0-95.0 wt% of indium oxide (In2O3) and 5.0-15.0 wt% of zinc oxide (ZnO) according to the weight percentage; the addition amount of the lanthanide-doped oxide accounts for 0.3-0.6 wt% of the total mass of the main base powder, the lanthanide-doped oxide comprises praseodymium oxide (Pr6O 11 ) and neodymium oxide (Nd2O3), and the mass ratio of praseodymium oxide to neodymium oxide is (3-8.5):(1.5-7). Preferably, the relative density of the target material is not less than 99%, the grain size is 5-7 μm, and the volume resistivity is not higher than 4.0×10 -4 Ω·cm.

[0024] Next, to realize the preparation of the above-mentioned high-performance target material, the present application also provides a preparation method matched therewith. The core of the method is to realize the whole-process accurate control of the slurry rheological state and material sintering kinetics through the synergy of powder calcination and collaborative treatment, double dispersant collaborative dispersion system construction, lanthanide co-doping energy band-grain boundary collaborative mechanism optimization, and the synergy of the following four-stage grinding and precision sintering atmosphere system, which is the key to obtain target material with ultra-high density, ultra-fine grain and excellent electrical properties. The steps of the method will be described in detail below.

[0025] (1) Powder calcination High-purity (4N) indium oxide (In2O3) powder (D50=0.6μm) was divided into multiple groups with different mass ratios and calcined separately in air at 600-1200℃ for 2-4 hours. The powders calcined at different temperatures were then blended to obtain In2O3 raw materials with optimized lattice distortion energy and reduced hydroxyl impurities. High-purity (4N) zinc oxide (ZnO) powder (D50=0.6μm) was calcined in a carbon-buried atmosphere (carbon powder:ZnO=1:5) at 800-1000℃ for 2-4 hours to inhibit high-temperature decomposition of ZnO and stabilize oxygen vacancy concentration.

[0026] (2) Mixing and grinding (2-1) The calcined In2O3 powder, ZnO powder, lanthanide-doped oxide powder with a particle size ≤200nm, a first dispersant (added at 0.5-1.5wt% of the total mass of the powder), and high-purity water (resistivity >18MΩ·cm) are mixed and dispersed by high-speed shearing for 12-24 hours to obtain a first dispersion slurry with a solid content of 55-65wt%. (2-2) The first dispersion slurry is subjected to ultrasonic treatment for 10-30 minutes to further break down soft agglomerates; (2-3) Add a second dispersant (0.5-1.5 wt% of the total mass of the powder), a binder (1.5-3.0 wt% of the total mass of the powder), and a defoamer (polydimethylsiloxane, 0.05-0.1 wt% of the total mass of the first dispersion slurry) to the ultrasonically dispersed slurry, and then perform horizontal sand milling.

[0027] Traditional single-speed grinding cannot simultaneously address changes in particle state during the grinding process, easily leading to low grinding efficiency or over-grinding. The four-stage variable-speed grinding strategy designed in this invention dynamically matches different stages of particle refinement: Phase 1 (550-650 rpm, 0.1-2 h): High speed and high shear force are used, with the primary purpose of impacting and breaking down hard agglomerates in the powder, laying the foundation for subsequent efficient refining; Phase 2 (450-550 rpm, 2-8 h): The rotation speed is appropriately reduced but the energy is still maintained. The core goal is efficient grinding, which quickly refines the broken particles to the target particle size range. This phase is the main phase of particle size reduction. Stage 3 (350-450 rpm, 8-18 h): Further reduce the rotation speed. At this point, the particles are already quite fine, and the goal is to balance shear force and Brownian motion (diffusion force). Excessive shear force may induce secondary agglomeration of fine particles. This stage achieves fine grinding through moderate shear force, while relying on diffusion to prevent particle agglomeration and ensure uniform particle size distribution (D90≤0.5μm). Stage four (250-350 rpm, 18-24 h): low rotation speed is adopted, the main purpose of which is not to break or refine, but to eliminate the internal stress (such as mechanical shear stress) of the slurry system, and to realize the final homogeneous dispersion of the particles, so as to obtain a slurry with good rheological properties, which can provide guarantee for obtaining uniform spherical granulated powder by subsequent spray drying.

[0028] The D90 of the slurry is controlled to be less than 0.5 μm, and then the pH of the slurry is adjusted to 7.0 ± 0.2 by using ammonia water to obtain a second dispersion slurry.

[0029] Preferably, the second dispersant and the defoaming agent are uniformly added in the four grinding stages, and the binder is added in the last 1-2 hours of stage four to avoid the premature destruction of its molecular chain by mechanical shear.

[0030] (3) Granulation and forming The second dispersion slurry is spray granulated, and the obtained powder is first dry-pressed at 60 MPa, and then cold isostatic pressed (CIP) at 230 MPa to form a green body with a relative density greater than 60%.

[0031] (4) Normal pressure sintering The design of the sintering schedule directly determines the final microstructure, stoichiometric ratio and electrical properties of the target material.

[0032] The debinding stage (room temperature-600°C, nitrogen atmosphere): slow heating (0.5°C / min) in an inert nitrogen atmosphere can ensure that the organic matters such as binders and dispersants are smoothly and completely decomposed and removed, and the blistering, cracking or residual carbon of the green body caused by rapid oxidation and decomposition is avoided.

[0033] The sintering stage (600-1450°C, pure oxygen atmosphere): switching to a pure oxygen atmosphere aims to inhibit the volatilization and decomposition of indium and zinc elements. For In2O3, an oxygen-rich environment can inhibit its high-temperature decomposition; for ZnO, it can inhibit its reduction to metallic Zn and volatilization. The strategy of two-stage heating (600-1200°C: 1°C / min; 1200-1450°C: 0.1°C / min) is: a relatively fast rate is adopted in the early stage to pass through the intermediate temperature interval, and a very slow heating rate is adopted in the highest temperature zone close to the melting point in the later stage to give sufficient diffusion and mass transfer time to realize the full growth of the grains and the exclusion of pores, so as to obtain a dense structure close to the theoretical density (>99.5%), while the abnormal growth of the grains is maximally inhibited.

[0034] Cooling stage (1450℃ - room temperature, pure oxygen → air): The high-temperature zone (1450-1000℃) is slowly cooled (0.5℃ / min) in a pure oxygen atmosphere. This prevents the product from cracking due to rapid cooling and helps stabilize the oxygen vacancy concentration inside the material, thereby optimizing electrical properties. After cooling to below 1000℃, the atmosphere is switched to air, which is an economical and effective cooling method. This also ensures that the product is moderately oxidized, maintaining a stable chemical state. Finally, the desired target material is obtained.

[0035] The technical features of the present invention will be further described below with reference to embodiments and comparative examples.

[0036] Example 1 (Optimal Ratio) The target material comprises a main component powder and lanthanide-doped oxides. The main component powder contains 89.3 wt% In₂O₃ and 10.7 wt% ZnO; the total amount of lanthanide-doped oxides added is 0.50 wt% (percentage of the main component mass), of which praseodymium oxide (Pr₆O₃) is present. 11 0.30 wt% of the total composition, and 0.20 wt% of the total composition, of which neodymium oxide (Nd2O3) is present.

[0037] The preparation method of this target material is as follows: Step (1): 4N grade In2O3 powder (D50=0.6μm) was divided into four groups according to a mass ratio of 1:2:4:3, and calcined in air at 600℃, 800℃, 1000℃ and 1200℃ for 4h respectively, and then used in combination; 4N grade ZnO powder was calcined in a carbon atmosphere (carbon powder:ZnO=1:5) at 950℃ for 2h. Step (2): The calcined powder was mixed with lanthanide-doped oxide, 0.8 wt% of the first dispersant ammonium citrate (CA-NH4), and pure water, and dispersed by high-speed shearing for 12 h to obtain a first dispersion slurry with a solid content of 60 wt%. After ultrasonic treatment for 20 min, it was transferred to a sand mill. During the grinding process, a total of 1.2 wt% of the second dispersant ammonium polyacrylate (PAA-NH4), 1.5 wt% of the binder PVA, and 0.05 wt% of the defoamer PDMS were added. The mixture was ground at four speeds (600 rpm / 2 h → 500 rpm / 6 h → 400 rpm / 10 h → 300 rpm / 6 h) for 24 h. The slurry D90 was 0.48 μm. The pH was adjusted to 7.0 with ammonia water to obtain the second dispersion slurry. Step (3): After the second dispersion slurry is spray-dried, it is formed by dry pressing at 60MPa and cold isostatic pressing at 230MPa, with a green density of 62%; Step (4): ① Defatting stage (room temperature-600℃) using nitrogen atmosphere, heating rate 0.5℃ / min; ② Sintering stage using pure oxygen atmosphere, 600-1200℃, heating rate 1℃ / min; 1200-1450℃, heating rate 0.1℃ / min; ③ Cooling stage dynamically switching the atmosphere in the furnace, 1450-1000℃ using pure oxygen atmosphere, cooling rate 0.5℃ / min; 1000℃-room temperature using air atmosphere, cooling rate 0.5℃ / min; Step (5): Using the target to prepare 300nm thick IZO film on glass substrate by DC sputtering (power 450W, Ar / O2=99:1, working pressure 0.5Pa, substrate temperature 180℃).

[0038] Wherein, the relative density of the target obtained in step (4) is 99.5%, the grain size is 5.5μm, and the resistivity is 3.5×10 -4 Ω•cm; the resistivity of the film obtained in step (5) is 3.8×10 -4 Ω•cm, and the electron mobility is 68cm 2 / V•s.

[0039] Example 2 (high Pr ratio, insufficient grain boundary passivation) The difference from Example 1 is only that the ratio of praseodymium oxide and neodymium oxide in the lanthanide doped oxide is adjusted, wherein the praseodymium oxide accounts for 0.40wt%, and the neodymium oxide accounts for 0.08wt%.

[0040] The relative density of the obtained IZO target is 99.4%, the grain size is 6.5μm, and the resistivity is 3.2×10 -4 Ω·cm. The resistivity of the obtained IZO film is 3.5×10 -4 Ω·cm, and the electron mobility is 61cm 2 / V•s.

[0041] Example 3 (high Nd ratio, insufficient carrier concentration) The difference from Example 1 is only that the ratio of praseodymium oxide and neodymium oxide in the lanthanide doped oxide is adjusted, wherein the praseodymium oxide accounts for 0.15wt%, and the neodymium oxide accounts for 0.35wt%.

[0042] The relative density of the obtained IZO target is 99.3%, the grain size is 5.5μm, and the resistivity is 3.7×10 -4 Ω·cm. The resistivity of the obtained IZO film is 4.1×10 -4 Ω·cm, and the electron mobility is 57cm 2 / V•s.

[0043] Comparative Example 1 (IZO target doped with Pr only) The difference from Example 1 is that the lanthanide doped oxide only introduces 0.5wt% of praseodymium oxide.

[0044] The obtained IZO target material has a relative density of 98.7%, a grain size of 6.5 μm, and a resistivity of 4.5 x 10 -4 Ω·cm. The obtained IZO thin film has a resistivity of 4.8 x 10 -4 Ω·cm, and an electron mobility of 50 cm 2 / V·s.

[0045] Comparative Example 2 (IZO target material doped with Nd alone) The difference from Example 1 is that the lanthanide doped oxide only introduces 0.5wt% of neodymium oxide.

[0046] The obtained IZO target material has a relative density of 98.9%, a grain size of 5.8 μm, and a resistivity of 4.7 x 10 -4 Ω·cm. The obtained IZO thin film has a resistivity of 5.1 x 10 -4 Ω·cm, and an electron mobility of 52 cm 2 / V·s.

[0047] Comparative Example 3 (powder not subjected to calcination and synergistic treatment) The difference from Example 1 is that step (1) is not included.

[0048] The obtained IZO target material has a relative density of 97.8%, a grain size of 6.5 μm, and a resistivity of 4.8 x 10 -4 Ω·cm. The obtained IZO thin film has a resistivity of 5.2 x 10 -4 Ω·cm, and an electron mobility of 55 cm 2 / V·s.

[0049] Comparative Example 4 (no double dispersant introduced into the synergistic dispersion system) The difference from Example 1 is that the first dispersant ammonium citrate (CA-NH4) is not introduced in step (2), and only 1.2wt% of the second dispersant ammonium polyacrylate (PAA-NH4) is introduced into the total mass of the powder.

[0050] The obtained IZO target material has a relative density of 95.2%, a grain size of 6.0 μm, and a resistivity of 4.9 x 10 -4 Ω·cm. The obtained IZO thin film has a resistivity of 5.1 x 10 -4 Ω·cm, and an electron mobility of 54 cm 2 / V·s.

[0051] Comparative Example 5 (conventional IZO) The conventional IZO target material is used, the target material is composed of 89.3wt% of indium oxide (In2O3) and 10.7wt% of zinc oxide (ZnO), and no other doping is conducted.

[0052] Under the same coating process conditions, the resistivity of the thin film is 5.2*10 -4 Ω*cm, and the electron mobility is 40cm 2 / V*s.

[0053] Comparative Example 6 (conventional ITO) The conventional IZO target material is used, the target material is composed of 89.3wt% of indium oxide (In2O3) and 10.7wt% of zinc oxide (ZnO), and no other doping is conducted.

[0054] Under the same coating process conditions, the resistivity of the thin film is 5.2*10 -4 Ω*cm, and the electron mobility is 40cm 2 / V*s.

[0055] According to the performance data comparison between the examples and the comparative examples, the target material with the mobility (up to 68cm 2 / V*s) significantly superior to the conventional IZO and ITO, and the resistivity is low, is successfully prepared by the synergistic effect of the praseodymium-neodymium co-doping, the powder calcination, the double dispersing agent and the segmented sintering process.

[0056] The above is only the preferred embodiment of the present application, and is not intended to limit the present application in any form. Any equivalent transformation or modification according to the essence of the present application should be covered in the protection scope of the present application.

Claims

1. A high mobility praseodymium-neodymium co-doped indium zinc oxide sputtering target material, characterized in that, The main element powder comprises 85.0-95.0 wt% of indium oxide and 5.0-15.0 wt% of zinc oxide; The adding amount of the lanthanide-doped oxide accounts for 0.3-0.6 wt% of the total mass of the main element powder, the lanthanide-doped oxide comprises praseodymium oxide and neodymium oxide, and the praseodymium oxide accounts for 30%~85% of the total mass of the lanthanide-doped oxide.

2. The high mobility praseodymium and neodymium co-doped indium zinc oxide sputtering target of claim 1, wherein, The relative density of the target is not less than 99%, the grain size is 5-7 μm, and the resistivity is not higher than 4.0×10 -4 Ω·cm.

3. The high mobility praseodymium and neodymium co-doped indium zinc oxide sputtering target of claim 1, wherein, The particle size of the lanthanide-doped oxide is ≤200 nm.

4. A method of producing a high mobility praseodymium-neodymium co-doped indium zinc oxide sputtering target according to any one of claims 1 to 3, characterized by, The method comprises the following steps: Step (1), powder calcination The indium oxide powder is calcined in air atmosphere at 600-1200℃ for 2-4h in multiple groups, and is used after compounding; The zinc oxide powder is calcined in carbon-embedded atmosphere at 800-1000℃ for 2-4h; Step (2), mixing and grinding (2-1), the calcined indium oxide powder, zinc oxide powder and lanthanide-doped oxide powder are mixed with the first dispersant and pure water, and are subjected to high-speed shearing dispersion to obtain a first dispersion slurry, and the solid content of the first dispersion slurry is 55-65 wt%; (2-2), the first dispersion slurry is subjected to ultrasonic treatment; (2-3), the first dispersion slurry subjected to ultrasonic treatment is subjected to grinding treatment, and the second dispersant, the binder and the defoaming agent are added during the grinding process; The grinding treatment adopts four-stage speed control: Stage one: grinding at a speed of 550-650 rpm for 0.1-2h; Stage two: grinding at a speed of 450-550 rpm for 2-8h; Stage three: grinding at a speed of 350-450 rpm for 8-18h; Stage four: grinding at a speed of 250-350 rpm for 18-24h; The D90 of the slurry after grinding is controlled to be ≤0.5μm, and the pH is adjusted to 6.8-7.2 to obtain a second dispersion slurry; Step (3), granulation and forming The obtained second dispersion slurry is spray dried to obtain a powder, and the powder is sequentially subjected to dry pressing and cold isostatic pressing to obtain a green body; Step (4), normal pressure sintering The sintering step is performed according to the following system: Degreasing stage: under nitrogen atmosphere, the temperature is raised from room temperature to 600℃ at a rate of 0.5℃ / min; Sintering stage: under pure oxygen atmosphere, the temperature is raised from 600℃ to 1200℃ at a rate of 1℃ / min, and then the temperature is raised from 1200℃ to 1450℃ at a rate of 0.1℃ / min; Cooling stage: under pure oxygen atmosphere, the temperature is lowered from 1450℃ to 1000℃ at a rate of 0.5℃ / min, and then under air atmosphere, the temperature is lowered from 1000℃ to room temperature at a rate of 0.5℃ / min; Finally, the sputtering target material is obtained.

5. The method of claim 4, wherein the method is characterized by: In the step (2-1), the adding amount of the first dispersant is 0.5-1.5 wt% of the total mass of the main element powder and the lanthanide-doped oxide; The first dispersant is selected from one or more of ammonium citrate, polyammonium aspartate, polyammonium methacrylate, hydrolyzed polyacrylonitrile ammonium salt, hyperbranched polyglycerol ether and sulfonated polystyrene ammonium salt.

6. The method of claim 4, wherein the method is characterized by: The second dispersant is added in an amount of 0.5-1.5wt% of the total mass of the main unit powder and the lanthanide-doped oxide; The defoaming agent is added in an amount of 0.05-0.1wt% of the total mass of the first dispersion slurry; The binder is added in an amount of 1.5-3.0wt% of the total mass of the main unit powder and the lanthanide-doped oxide.

7. The method of claim 4, wherein the sintering is performed at a temperature of 1,100°C to 1,300°C for 1 to 10 hours. The second dispersant in the step (2-3) is selected from one or more of polyacrylic acid ammonium, sodium gluconate, ethylenediamine tetraacetate ammonium, ammonium tartrate, ammonium lauryl sulfate, diethylene triamine pentaacetate ammonium; The defoaming agent is polydimethylsiloxane; The binder is one or more of polyvinyl alcohol, polyethylene glycol-1000, polymethacrylic acid, carboxymethyl cellulose, etc.

8. The method of claim 4, wherein the method is characterized by: The second dispersant and the defoaming agent are uniformly added in the grinding process of the stages one to four in the step (2-3); and the binder is added in the last 1-2 hours of the stage four.

9. The method of claim 4, wherein the sintered Pr-Nd co-doped indium zinc oxide sputtering target has a relative density of 95% or more. In the step (3), the powder is dry-pressed at 60MPa and then cold isostatic pressed at 230MPa, and the obtained green body density is greater than 60%.

10. The method of claim 4, wherein the method is characterized by: In the step (1), the indium oxide powder is divided into four groups in a mass ratio of (1-2):(2-4):(3-5):(2-4), and is calcined at calcination temperatures of 600℃, 800℃, 1000℃ and 1200℃, respectively.