LU504172B1

LU504172B1 - Praseodymium doped indium zinc oxide sputtering target and preparation method therefor

Info

Publication number: LU504172B1
Application number: LU504172A
Authority: LU
Inventors: Zhijun Wang; Miao Liu; Bingxue Han; Yang Liu; Chengduo Wang; Benshuang Sun; Jie Chen; Jilin He; Xueyun Zeng
Original assignee: Univ Zhengzhou
Priority date: 2023-01-31
Filing date: 2023-05-10
Publication date: 2023-11-10
Also published as: CN115925410A; CN115925410B

Abstract

Embodiments of the present invention disclose a preparation method for a praseodymium doped indium zinc oxide sputtering target, including: mixing a Pr2O3 powder, an In2O3 powder, and a ZnO powder at a set mass ratio, and adding additives to prepare a slurry; sand milling the slurry to obtain a slurry containing single sized particles; performing spray granulation on the slurry to obtain a spherical granulated powder; molding the spherical granulated powder to obtain a target blank; and performing integrated debinding and sintering treatment on the target blank, where a sintering process in the integrated debinding and sintering treatment includes: heating the target blank from a debinding temperature to a first step temperature of 850-1150℃ at a heating rate of 3-5℃/min, and preserving heat for 8-24 hours; heating the target blank from the first step temperature to a second step temperature of 1450-1550℃ at a heating rate of 5-10℃/min, and skipping heat preservation; cooling the target blank from the second step temperature to a third step sintering temperature of 1150-1250℃ at a cooling rate of 10-20℃/min, and preserving heat for 12-36 hours; cooling the target blank from the third step temperature to 600℃ at a cooling rate of 1-3℃/min; and then naturally cooling the target blank to obtain a praseodymium doped indium zinc oxide sputtering target with fine grains and a controllable secondary phase.

Description

PRASEODYMIUM DOPED INDIUM ZINC OXIDE SPUTTERING Hone

TARGET AND PREPARATION METHOD THEREFOR

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present invention belongs to the technical field of sputtering targets, and in particular to a praseodymium doped indium zinc oxide sputtering target and a preparation method therefor.

[0003] 2. Description of Related Art

[0004] Thin film transistors (TFT) are a kind of widely used semiconductor devices.

Existing TFT materials mainly include amorphous silicon, polycrystalline silicon, and metal oxides. Metal oxide thin film transistors (MO-TFT) have been widely used in fields of display devices, semiconductor chips, photovoltaic cells, and the like due to their advantages of good uniformity, high mobility, high visible light transmittance, and easy production. Thin films of a zinc oxide and doped systems thereof (IZO/TZO/IGZO) have advantages of high intrinsic mobility (10-50 cm?/Vs), high etching speed, few particle production, capability of obtaining amorphous films and no annealing treatment, and therefore show excellent performance in use of LCD, OLED, and the like.

[0005] Different composition proportions of IGZO as a mixed system of a ternary oxide material may lead to different performance of TFT. Mobilities of TFT devices of a conventional IGZO system are generally about 10 cm?/Vs. By increasing indium content, the mobility can be improved to a certain extent, but the stability will decline. With continuous upgrade of 8K ultra-high definition LCD and OLED display specifications with high refresh rates above 120 Hz, the conventional IGZO system cannot meet performance requirements of higher-order products in terms of mobility and stability, so it is urgent to develop a new 1 generation of high-performance oxide materials with high mobility and stability to meet the PORTE development of display industry.

[0006] Compared with an IGZO thin film, an IZO thin film often has higher intrinsic electron mobility (30 cm?/Vs). However, when used as a transistor, the IZO thin film also has some limitations, such as high resistivity, low switching ratio, and poor bias stress stability. As a channel layer material in TFT devices, the [ZO thin film has advantages of excellent electron mobility, good visible light transmittance, simple fabrication, and the like. Generally, properties of a thin film are determined by properties of a sputtering target and sputtering parameters. The surface morphology, amorphous structure, carrier concentration and mobility of the IZO thin film are closely related to the performance of an IZO target. At present, the utilization rate of a sputtering target is only 40%-60%, which greatly limits its use in large-sized, large-scale, and high-end display devices. The high density and low porosity of the target can effectively retard an arc phenomenon and nodule formation in a sputtering process.

[0007] In order to improve the performance of the IZO target, many attempts have been made in the prior art. Patent CN113292315A discloses a rare earth doped indium zinc oxide powder, a preparation method therefor, and a use thereof, where a mass percentage of a rare earth oxide powder, an indium oxide powder, and a zinc oxide powder is (8-10.5): (78-80.5): 13. Patent CN112079626A discloses a praseodymium indium zinc oxide thin film transistor and a preparation method therefor, where a mass percentage of Nd2O3: In203: ZnO is 1%: 62.5%: 36.5%, and a suitable carrier inhibitor NdzO; is introduced to control transport of carriers, thereby realizing an IZO-TFT thin film transistor with high mobility and high current switching ratio at room temperature. Patent CN113735564A discloses a Nb doped IZO target blank and a preparation method therefor, where the target blank is sintered from the following oxides in parts by mass: 90 parts of In2O3, 8 parts of ZnO, and 0.01-0.1 part of Nb2Os. The resistivity of a Nd-IZO target obtained by this method reaches (1.3-1.5)x10*Q-cm. However, 2 the rare earth element has a unique 4f electronic structure and a high state density. In addition, 5 an ion radius of the rare earth element is quite different from a radius of doped zinc ions.

Therefore, how to control a doping amount of rare earth element and achieve effective doping is currently a difficulty in research of rare earth doped IZO targets.

[0008] BRIEF SUMMARY OF THE INVENTION

[0009] In view of this, on the one hand, some embodiments disclose a preparation method for a praseodymium doped indium zinc oxide sputtering target, including steps of:

[0010] (1) mixing a Pr,O3 powder and an In203 powder at a set mass ratio, and adding additives to prepare a slurry;

[0011] (2) sand milling the slurry with high energy;

[0012] (3) adding a set amount of ZnO powder into the sand-milled slurry, and sand milling the slurry to obtain a slurry containing single sized particles, where in the slurry, mass content of Pr203 is 0.05-5 wt%, and a mass ratio of In203 to ZnO is (60-70): (40-30);

[0013] (4) performing spray granulation on the slurry obtained in step (3) to obtain spherical granulated powders;

[0014] (5) performing mold pressing preforming and cold isostatic pressing reinforced forming on the spherical granulated powder sequentially to obtain a target blank; and

[0015] (6) performing integrated debinding and sintering treatment on the obtained target blank to obtain a praseodymium doped indium zinc oxide sputtering target with fine grains and controllable secondary phases;

[0016] where a sintering process in the integrated debinding and sintering treatment includes:

[0017] heating the target blank from a debinding temperature to a first step temperature of 850-1150°C at a heating rate of 3-5°C/min, and preserving heat for 8-24 hours;

[0018] then heating the target blank from the first step temperature to a second step 3 temperature of 1450-1550°C at a heating rate of 5-10°C/min, and skipping heat preservation; Hone

[0019] cooling the target blank from the second step temperature to a third step sintering temperature of 1150-1250°C at a cooling rate of 10-20°C/min, and preserving heat for 12-36 hours; and

[0020] cooling the target blank from the third step temperature to 600°C at a cooling rate of 1-3°C/min; and then naturally cooling the target blank.

[0021] In the preparation method for a praseodymium doped indium zinc oxide sputtering target according to some embodiments, the additives include a dispersant, a binder, and deionized water, and in the slurry containing single sized particles, a mass ratio of the dispersant to the powder is 1-3%, a mass ratio of the binder to the powder is 0.1-0.5%, and a mass ratio of the deionized water to the powder is 60-120%.

[0022] In the preparation method for a praseodymium doped indium zinc oxide sputtering target according to some embodiments, the spray granulation is performed on the slurry in a granulator, and the granulator has an inlet temperature of 200-300°C, an exhaust temperature of 80-100°C, and a frequency of 30-50 Hz.

[0023] In the preparation method for a praseodymium doped indium zinc oxide sputtering target according to some embodiments, molding pressure for forming the target blank is 30-80 MPa, and cold isostatic pressure is 200-300 MPa.

[0024] In the preparation method for a praseodymium doped indium zinc oxide sputtering target according to some embodiments, in the integrated debinding and sintering treatment, a debinding temperature is 400-600°C, a debinding heating rate is 0.5-1°C/min, a heat preservation time is 6-12 h, a debinding gas is air, and a flow rate of the air is 10-50

L/min.

[0025] In the preparation method for a praseodymium doped indium zinc oxide sputtering target according to some embodiments, a sintering gas is oxygen, and a flow rate of 4 the oxygen is 50-200 L/min.

[0026] In the preparation method for a praseodymium doped indium zinc oxide sputtering target according to some embodiments, in step (1), a viscosity of the slurry is controlled to 35-45 mPa-s.

[0027] In the preparation method for a praseodymium doped indium zinc oxide sputtering target according to some embodiments, in step (1), the slurry has a solid content of 50-70%.

[0028] In the preparation method for a praseodymium doped indium zinc oxide sputtering target according to some embodiments, the target blank in step (5) has a relative density of not less than 63%.

[0029] On the other hand, some embodiments disclose a praseodymium doped indium zinc oxide sputtering target. The praseodymium doped indium zinc oxide sputtering target has a relative density of not less than 99.6% and a resistance of 0.2-6 mQ-cm.

[0030] According to the preparation method for a praseodymium doped indium zinc oxide sputtering target disclosed in the embodiments of the present invention, content of a praseodymium oxide in a mixed powder is strictly controlled to obtain a praseodymium doped indium zinc oxide sputtering target with a uniform secondary phase, a small grain size, uniform distribution, high target density, and excellent electrical performance, where the mixed powder with uniform size distribution is obtained by a spray granulation process; the target blank is sintered at a set flow rate of oxygen by using an integrated debinding and sintering treatment method combined with a multi-step variable temperature sintering process, so as to inhibit abnormal growth of ZnO grains, obtain fine grains, reduce generation of oxygen vacancies, and improve density of the target; and the praseodymium doped indium zinc oxide sputtering target with a uniform and refined structure is finally obtained, with a relative density of not less than 99.6% and a resistance of 0.2-6 mQ-cm.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 1°

[0031] Fig. 1 is an SEM view of a PrIZO granulated powder prepared in Example 1; and

[0032] Fig. 2 1s a view of a phase structure of a PrIZO target prepared in Example 1.

DETAILED DESCRIPTION OF THE INVENTION

[0033] With regard to the dedicated term "embodiment" herein, any embodiment described as "exemplary" need not be construed as being superior or better than other embodiments. Unless otherwise specified, performance index tests in the embodiments of the present invention use conventional test methods in the art. It should be understood that the terms used in the present invention are only for describing specific embodiments, rather than limiting the disclosure of the embodiments of the present invention.

[0034] Unless otherwise specified, technological and scientific terms used herein have the same meanings commonly understood by those of ordinary skill in the technical field to which the embodiments of the present invention belong. Other test methods and technical means not specifically noted in the embodiments of the present invention all refer to those commonly used by those of ordinary skill in the art.

[0035] The terms "substantially" and "approximately" used herein are used to describe small fluctuations. For example, they may indicate less than or equal to +5%, such as less than or equal to +2%, less than or equal to +1%, less than or equal to £0.5%, less than or equal to +0.2%, less than or equal to + 0.1%, or less than or equal to +0.05%. Numerical data expressed or presented in a format of a range herein are only used for convenience and brevity, and therefore, should be flexibly interpreted to include not only values explicitly listed as limits of the range, but also all independent values or sub-ranges included within the range. For example, a numerical range of "1-5%" should be interpreted to include not only values explicitly listed from 1% to 5%, but also individual values and sub-ranges within the indicated range. Therefore, independent values, such as 2%, 3.5%, and 4%, and sub-ranges, such as 1%-3%, 2%-4%, and 6

3%-5% are included in the numerical range. This principle also applies to a range that lists only ate one value. In addition, such interpretation applies regardless of the width of the range or the characteristics described.

[0036] In the specification including the claims, conjunctions such as "include", "comprise", "with", "have", "contain", "relate", "accommodate", etc. are interpreted as open, indicating "include but not limited to". Only the conjunctions "consist of" and "composed of" are closed conjunctions.

[0037] In order to better explain the content of the present invention, many specific details are provided in the specific embodiments below. It should be appreciated by those skilled in the art that the present invention may also be practiced without some specific details.

In the embodiments, some methods, means, instruments, devices, and the like that are well known to those skilled in the art are not described in detail in order to highlight the main idea of the present invention.

[0038] The technical features disclosed in the embodiments of the present invention may be combined arbitrarily on a non-conflict premise, and the obtained technical solutions belong to the disclosure of the embodiments of the present invention.

[0039] In some embodiments, a preparation method for a praseodymium doped indium zinc oxide sputtering target includes the following steps:

[0040] (1) A Pr2O3 powder and an In2O3 powder are mixed at a set mass ratio, and additives are added to prepare a slurry; generally, the raw powders have a purity of more than 99.99%, and content of a praseodymium oxide in the slurry needs to be strictly controlled to prevent excessive praseodymium oxide and inhibit densification of a final sputtering target, where the densification may cause poor electrical performance of the sputtering target; generally, the additives contain a dispersant, which is beneficial to dispersion of oxide powders in a solution, and the dispersant can be completely removed in a subsequent debinding and 7 sintering process, without affecting performance of the sputtering target; the additives further ate contain a binder, which can ensure that a target blank has a proper density and is unlikely to crack in a subsequent target forming process, so as to obtain a high-density sputtering target; content of deionized water in the slurry also needs to be strictly controlled to ensure that the slurry has proper solid content, and that viscosity of the slurry is within an appropriate range, so as to obtain a slurry with a uniform and single oxide particle size by sand milling;

[0041] In some examples, the viscosity of the slurry is controlled to 35-45 mPa s;

[0042] In some examples, the slurry has a solid content of 50-70%;

[0043] (2) The slurry is sand-milled with high energy; in the process of sand milling with high energy, oxide particles in the slurry are crushed and ground into particles with smaller diameter and uniform distribution;

[0044] (3) A set amount of ZnO powder is added into the sand-milled slurry, and the slurry is sand-milled with high energy to obtain a slurry with single sized particles; in the slurry, a mass content of Pr203 is 0.05-5 wt%, and a mass ratio of In2O03 to ZnO is (60-70): (40-30) wt%; the slurry with single sized particles usually refers to uniform particle size distribution of oxide powders in the slurry; after the slurry containing raw powder particles of indium oxide, zinc oxide, and praseodymium oxide is sand-milled, the uniform particle size distribution of the mixed powders in the obtained slurry is conducive to obtaining a granulated powder with uniform oxide powder dispersion by a subsequent granulation process; generally, the sand milling process is performed in a sand mill; the indium oxide, zinc oxide, and praseodymium oxide powders in the slurry are efficiently sand-milled in the sand mill to form single sized particles, which effectively increase sintering activity of the powder; to obtain a uniform and high-density target, the three oxide powders should be soluble in each other, unlikely to agglomerate, and uniform in particle size distribution, so as to obtain a praseodymium doped indium zinc oxide powder with good sintering performance; in some examples, the slurry is 8 sand-milled in the sand mill for multiple cycles to obtain a slurry with a solid content of about ate 50-70%; in some examples, the sand-milled slurry is stood and aged for a period of time to fully grow grains, and generally, the grains are grew for half an hour, and preferably more than two hours; in some examples, in the sand milling process of the slurry, a revolving speed of the sand mill is set to 300-500 r/min, and a sand milling time is set to 0.5-2 h;

[0045] (4) Spray granulation is performed on the slurry obtained in step (3) to obtain a spherical granulated powder; in some examples, the spray granulation is performed on the slurry in a granulator, and the granulator has an inlet temperature of 200-300°C, an exhaust temperature of 80-100°C, and a frequency of 30-50 Hz; the obtained spherical granulated powder has a particle size of about 200-300 nm, uniform moisture content, uniform particle size distribution, and no agglomeration, which provides sintering driving force for sintering of oxide powders;

[0046] (5) Mold pressing preforming and cold isostatic pressing reinforced forming are performed on the spherical granulated powder sequentially to obtain a target blank; in some examples, molding pressure for the mold pressing preforming to obtain the target blank is 30-80

MPa, cold isostatic pressure for the cold isostatic pressing reinforced forming is 200-300 MPa, and the obtained target blank has a density of 60%-75%; and

[0047] (6) Integrated debinding and sintering treatment is performed on the obtained target blank to obtain a praseodymium doped indium zinc oxide sputtering target with fine grains and a controllable secondary phase.

[0048] A sintering process in the integrated debinding and sintering treatment includes a debinding process and a sintering process that are performed continuously.

[0049] The debinding process includes:

[0050] The target blank is heated to a debinding temperature of 400-600°C at a heating rate of 0.5-1°C/min, and heat is preserved for 6-12 h, where a debinding gas is air, and a flow 9

LU5041 72 rate of the air is 10-50 L/min.

[0051] The sintering process includes:

[0052] The debound target blank is heated from the debinding temperature to a first step temperature of 850-1150°C at a heating rate of 3-5°C/min, and heat is preserved for 8-24 hours, where a sintering gas is adjusted to oxygen, and a flow rate of the oxygen is 50-200 L/min;

[0053] then heating the target blank from the first step temperature to a second step temperature of 1450-1550°C at a heating rate of 5-10°C/min, and skipping heat preservation;

[0054] cooling the target blank from the second step temperature to a third step sintering temperature of 1150-1250°C at a cooling rate of 10-20°C/min, and preserving heat for 12-36 hours; and

[0055] cooling the target blank from the third step temperature to 600°C at a cooling rate of 1-3°C/min; and then naturally cooling the target blank.

[0056] Generally, a sintering process is performed in oxygen, which can inhibit generation of oxygen vacancies in the target and improve purity and density of the target; the sintering heating rate should not be too fast to avoid non-uniform heating of powders and incomplete reaction that cause cracking of the target, however, when the heating rate is too slow, the sintering time is too long, which is not conducive to production; generally, the sintering temperature cannot be more than 1600°C; because indium oxide decomposes at a high temperature of more than 1600°C,a sputtering target with high crystallinity, high purity, and uniform morphology cannot be obtained; generally, the sintering heat preservation time at the first step temperature should not be more than 25 h to prevent grain size growth due to a long heat preservation time.

[0057] In the preparation method for a praseodymium doped indium zinc oxide sputtering target according to some embodiments, the additives include a dispersant, a binder, and deionized water, and in the slurry containing single sized particles, a mass ratio of the dispersant to the powder is 1-3%, a mass ratio of the binder to the powder is 0.1-0.5%, and à PORTE mass ratio of the deionized water to the powder is 60-120%.

[0058] On the other hand, some embodiments disclose a praseodymium doped indium zinc oxide sputtering target. The praseodymium doped indium zinc oxide sputtering target has a relative density of not less than 99.6% and a resistance of 0.2-0.6 mQ-cm.

[0059] The technical details will be further exemplified below in conjunction with examples.

[0060] Example 1

[0061] A preparation method for a praseodymium doped indium zinc oxide sputtering target Pr-IZO, disclosed in Example 1, included the following steps:

[0062] (1) 9 g of Pr2O3 powder and 1260 g of In,O3 powder were mixed, and 900 g of deionized water, 18 g of dispersant, and 36 g of binder were added to prepare a slurry, where a solid content was 60 wt%, a viscosity of the slurry was 40 mPa-s, a mass ratio of In203 to ZnO was 70: 30, and a mass ratio of Pr203 to In203, ZnO, and Pr203 was 0.5: 100 ;

[0063] (2) The slurry was sand-milled with high energy to fully mix Pr203 and In20; and refine particles;

[0064] (3) 540 g of ZnO powder was added into the sand-milled slurry, and the slurry was sand-milled for a second time to obtain a slurry containing single sized particles;

[0065] (4) The slurry obtained in step (3) was pumped into a granulation tower for spray granulation, an inlet temperature of the granulator was set to 200°C, an exhaust temperature was set to 80°C, and a frequency was set to 30 Hz. À spherical granulated powder was obtained by the spray granulation, with a yield of about 82%;

[0066] (5) Mold pressing preforming and cold isostatic pressing reinforced forming were performed on the spherical granulated powder sequentially to obtain a target blank, where molding pressure was 30 MPa, cold isostatic pressure was 250 MPa, and the obtained target 11 blank had a relative density of 65%; and

[0067] (6) Integrated debinding and sintering treatment was performed on the obtained target blank, including:

[0068] The target blank was heated in an integrated debinding and sintering furnace to a debinding temperature of 500°C, heat was preserved for 16 hours, and the debound target blank directly entered a sintering process, where debinding was performed in air, and a flow rate of the air was 10 L/min;

[0069] The target blank was heated from the debinding temperature to a first step temperature of 1000°C at a heating rate of 3°C/min, and heat was preserved for 10 hours, where a sintering gas was oxygen, and a flow rate of the oxygen was 150 L/min;

[0070] Then the target blank was heated from the first step temperature to a second step temperature of 1550°C at a heating rate of 10°C/min, and heat preservation was skipped,

[0071] The target blank was cooled from the second step temperature to a third step sintering temperature of 1150°C at a cooling rate of 20°C/min, and heat was preserved for 20 hours; and

[0072] The target blank was cooled from the third step temperature to 600°C at a cooling rate of 3°C/min; and then the target was naturally cooled.

[0073] A finally obtained Pr-IZO sputtering target sintered body had a relative density of 99.8% and a volume resistivity of 0.2 mQ-cm.

[0074] Fig. 1 is an SEM view of a PrIZO granulated powder prepared in Example 1.

From the morphology, it can be seen that the composite powder had good spheroidization, uniform particle size distribution, and no agglomeration. Fig. 2 is a view of a phase structure of a PrIZO target prepared in Example 1, where the PrIZO target had a small grain size, uniform distribution, a single secondary phase, no obvious pores, and high density.

[0075] Example 2 12

[0076] A preparation method for a praseodymium doped indium zinc oxide sputtering ate target Pr-IZO, disclosed in Example 2, included the following steps:

[0077] (1) 18 g of Pr203 powder and 1260 g of In203 powder were mixed, and 900 g of deionized water, 18 g of dispersant, and 36 g of binder were added to prepare a slurry, where a solid content was 60 wt%, a viscosity of the slurry was 40 mPa-s, a mass ratio of In203 to ZnO was 70: 30 , and a mass ratio of Pr203 to In203, ZnO, and Pr203 was 1: 100;

[0078] (2) The slurry was sand-milled with high energy to fully mix Pr,O3 and In20; and refine particles;

[0079] (3) 540 g of ZnO powder was added into the sand-milled slurry, and the slurry was sand-milled for a second time to obtain a slurry containing single sized particles;

[0080] (4) The slurry obtained in step (3) was pumped into a granulation tower for spray granulation, an inlet temperature of the granulator was set to 200°C, an exhaust temperature was set to 80°C, and a frequency was set to 30 Hz. A spherical granulated powder was obtained by the spray granulation, with a yield of about 82%;

[0081] (5) Mold pressing preforming and cold isostatic pressing reinforced forming were performed on the spherical granulated powder sequentially to obtain a target blank, where molding pressure was 30 MPa, cold isostatic pressure was 250 MPa, and the obtained target blank had a relative density of 64%; and

[0082] (6) Integrated debinding and sintering treatment was performed on the obtained target blank, including:

[0083] The target blank was heated in an integrated debinding and sintering furnace to a debinding temperature of 500°C, heat was preserved for 16 hours, and the debound target blank directly entered a sintering process, where debinding was performed in air, and a flow rate of the air was 10 L/min; 13

[0084] The target blank was heated from the debinding temperature to a first step ate temperature of 1000°C at a heating rate of 3°C/min, and heat was preserved for 10 hours, where a sintering gas was oxygen, and a flow rate of the oxygen was 150 L/min;

[0085] Then the target blank was heated from the first step temperature to a second step temperature of 1550°C at a heating rate of 10°C/min, and heat preservation was skipped,

[0086] The target blank was cooled from the second step temperature to a third step sintering temperature of 1150°C at a cooling rate of 20°C/min, and heat was preserved for 20 hours; and

[0087] The target blank was cooled from the third step temperature to 600°C at a cooling rate of 3°C/min; and then the target was naturally cooled.

[0088] A finally obtained Pr-IZO sputtering target sintered body had a relative density of 99.8% and a volume resistivity of 0.2 mQ-cm.

[0089] Example 3

[0090] A preparation method for a praseodymium doped indium zinc oxide sputtering target Pr-IZO, disclosed in Example 3, was carried out with reference to the method disclosed in Example 2, where a mass ratio of Pr203 to In203, ZnO, and Pr;O3 was 2:100 ; a powder yield of spheroidization granulation was 85%; the target blank had a relative density of 65%; and a finally obtained Pr-IZO sputtering target sintered body had a relative density of 99.6% and a volume resistivity of 3 mQ-cm.

[0091] Example 4

[0092] A preparation method for a praseodymium doped indium zinc oxide sputtering target Pr-IZO, disclosed in Example 4, was carried out with reference to the method disclosed in Example 2, where a mass ratio of Pr203 to In203, ZnO, and Pr203 was 3:100; a powder yield of spheroidization granulation was 85%; the target blank had a relative density of 66%; and a finally obtained Pr-IZO sputtering target sintered body had a relative density of 99.6% and a 14

LU5041 72 volume resistivity of 5 mQ-cm.

[0093] Example 5

[0094] A preparation method for a praseodymium doped indium zinc oxide sputtering target Pr-IZO, disclosed in Example 5, was carried out with reference to the method disclosed in Example 2, where a mass ratio of Pr203 to In203, ZnO, and Pr203 was 4:100; a powder yield of spheroidization granulation was 85%; the target blank had a relative density of 63%; and a finally obtained Pr-IZO sputtering target sintered body had a relative density of 99.7% and a volume resistivity of 6 mQ-cm.

[0095] Example 6

[0096] A preparation method for a praseodymium doped indium zinc oxide sputtering target Pr-IZO, disclosed in Example 6, was carried out with reference to the method disclosed in Example 2, where a mass ratio of Pr203 to In203, ZnO, and Pr203 was 5:100 wt%; a powder yield of spheroidization granulation was 85%; the target blank had a relative density of 67%; and a finally obtained Pr-IZO sputtering target sintered body had a relative density of 99.8% and a volume resistivity of 3.2 mQ-cm.

[0097] According to the preparation method for a praseodymium doped indium zinc oxide sputtering target disclosed in the embodiments of the present invention, content of a praseodymium oxide in a mixed powder is strictly controlled to obtain a praseodymium doped indium zinc oxide sputtering target with a uniform secondary phase, a small grain size, uniform distribution, high target density, and excellent electrical performance, where the mixed powder with uniform size distribution is obtained by a spray granulation process; the target blank is sintered at a set flow rate of oxygen by using an integrated debinding and sintering treatment method combined with a multi-step variable temperature sintering process, so as to inhibit abnormal growth of ZnO grains, obtain fine grains, reduce generation of oxygen vacancies, and improve density of the target; and the praseodymium doped indium zinc oxide sputtering target with a uniform and refined structure is finally obtained, with a relative density of not less than ate 99.6% and a resistance of 0.2-6 mQ-cm, and therefore, has a good application prospect in the field of sputtering targets.

[0098] The technical solutions disclosed in the embodiments of the present invention and the technical details disclosed in the embodiments are merely illustrative of the inventive concept of the present invention, and do not constitute limitations to the technical solutions of the embodiments of the present invention. Any conventional changes, substitutions, combinations, or the like made to the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention, and shall fall within the protection scope of the claims of the present invention. 16

Claims

LU5041 72 What is claimed is:

1. A preparation method for a praseodymium doped indium zinc oxide sputtering target, comprising steps of: (1) mixing a Pr203 powder and an In203 powder at a set mass ratio, and adding additives to prepare a slurry; (2) sand milling the slurry with high energy; (3) adding a set amount of ZnO powder into the sand-milled slurry, and sand milling the slurry to obtain a slurry containing single sized particles, wherein in the slurry, mass content of Pr2O3 is 0.05-5 wt%, and a mass ratio of In203 to ZnO is (60-70): (40-30) wt%; (4) performing spray granulation on the slurry obtained in step (3) to obtain a spherical granulated powder; (5) performing mold pressing preforming and cold isostatic pressing reinforced forming on the spherical granulated powder sequentially to obtain a target blank; and (6) performing integrated debinding and sintering treatment on the obtained target blank to obtain a praseodymium doped indium zinc oxide sputtering target with fine grains and a controllable secondary phase; wherein a sintering process in the integrated debinding and sintering treatment comprises: heating the target blank from a debinding temperature to a first step temperature of 850-1150°C at a heating rate of 3-5°C/min, and preserving heat for 8-24 hours; then heating the target blank from the first step temperature to a second step temperature of 1450-1550°C at a heating rate of 5-10°C/min, and skipping heat preservation; cooling the target blank from the second step temperature to a third step sintering temperature of 1150-1250°C at a cooling rate of 10-20°C/min, and preserving heat for 12-36 hours; and cooling the target blank from the third step temperature to 600°C at a cooling rate of 17

1-3°C/min; and then naturally cooling the target blank.

2. The preparation method for a praseodymium doped indium zinc oxide sputtering target according to claim 1, wherein the additives comprise a dispersant, a binder, and deionized water; and in the slurry containing single sized particles, a mass ratio of the dispersant to the powder is 1-3%, a mass ratio of the binder to the powder is 0.1-0.5%, and a mass ratio of the deionized water to the powder is 60-120%.

3. The preparation method for a praseodymium doped indium zinc oxide sputtering target according to claim 1, wherein the spray granulation is performed on the slurry in a granulator, and the granulator has an inlet temperature of 200-300°C, an exhaust temperature of 80-100°C, and a frequency of 30-50 Hz.

4. The preparation method for a praseodymium doped indium zinc oxide sputtering target according to claim 1, wherein molding pressure for forming the target blank is 30-80 MPa, and cold isostatic pressure is 200-300 MPa.

5. The preparation method for a praseodymium doped indium zinc oxide sputtering target according to claim 1, wherein in the integrated debinding and sintering treatment, a debinding temperature is 400-600°C, a debinding heating rate is 0.5-1°C/min, a heat preservation time is 6-12 h, a debinding gas is air, and a flow rate of the air is 10-50 L/min.

6. The preparation method for a praseodymium doped indium zinc oxide sputtering target according to claim 1, wherein a sintering gas is oxygen, and a flow rate of the oxygen is 50-200 L/min.

7. The preparation method for a praseodymium doped indium zinc oxide sputtering target according to claim 1, wherein in step (1), a viscosity of the slurry is controlled to 35-45 mPa s.

8. The preparation method for a praseodymium doped indium zinc oxide sputtering target according to claim 1, wherein in step (1), the slurry has a solid content of 50-70%.

9. The preparation method for a praseodymium doped indium zinc oxide sputtering target 18 according to claim 1, wherein the target blank in step (5) has a relative density of not less than ate

63%.

10. A praseodymium doped indium zinc oxide sputtering target, obtained by the preparation method for a praseodymium doped indium zinc oxide sputtering target according to any one of claims 1-9, wherein the praseodymium doped indium zinc oxide sputtering target has a relative density of not less than 99.6% and a resistance of 0.2-6 mQ-cm. 19