MOS target, method for manufacturing the same, and thin-film transistor

Abstract

The present invention relates to the technical field of target manufacturing and provides a MOS target, a method for manufacturing the same, and a thin-film transistor. The manufacturing method includes the steps of: co-precipitating a mixed salt solution of three types of ions, In, Ga, and Sn, a precipitating agent, and a complexing agent, washing and concentrating the mixture to obtain high-purity indium gallium tin hydroxide colloid; hydrothermally reacting the high-purity indium gallium tin hydroxide colloid with an auxiliary agent, washing and drying the mixture to obtain first indium gallium tin oxide powder; performing a calcination treatment on the first indium gallium tin oxide powder to obtain second indium gallium tin oxide powder; ball-milling the second indium gallium tin oxide powder, a dispersant, an antifoaming agent, and pure water to obtain a slurry; casting the slurry to obtain a molded body; and sintering the molded body under high-oxygen conditions to obtain a MOS target. This invention combines coprecipitation, hydrothermal reaction, and calcination to precisely control the oxygen content of the powder, resulting in slight deoxygenation. This prevents the deoxygenation of In2O3 during the sintering process of the molded body, which would otherwise affect the conductivity of the target by generating In2O or InO.

Description

[Technical Field]

[0001] <Cross-reference of related applications> This application claims priority to Patent Application No. 202510194523.2 (Title of Invention: MOS Target, Method for Manufacturing the Same and Thin-Film Transistor), filed with the China National Intellectual Property Office on 21 February 2025, and all contents thereof are incorporated herein by reference. This invention belongs to the technical field of target manufacturing, and more particularly to MOS targets, methods for manufacturing the same, and thin-film transistors. [Background technology]

[0002] MOS (metal-oxide-semiconductor) thin films have advantages such as high mobility, low manufacturing temperature, transparency in the visible light region, and good electrical stability, making them an ideal material for the active layer of oxide thin-film transistors (TFTs). As display technology rapidly develops in the direction of larger size, ultra-high resolution, ultra-high refresh rate, and low power consumption, the demand for TFT mobility is increasing. Currently, the mobility of commonly used IGZO (In-Ga-Zn oxide) TFTs is approximately 200 cm². 2 ·V -1 ·s -1 However, this is far below the application standards for next-generation display technologies. Furthermore, because IGZO thin films contain Zn, they are easily etched when wet-etched at the source and drain, and the ZnO in IGZO thin films is sensitive to temperature, water vapor, etc., which can easily lead to unstable electrical performance for the sustained operation of IGZO TFTs. Therefore, in order to overcome the problem of low stability of IGZO, it is necessary to develop MOS targets that do not contain ZnO.

[0003] Furthermore, while the current manufacturing method for IGZO targets typically employs air sintering under atmospheric pressure, when In2O3 in the molded body is sintered at high temperatures under normal pressure and air conditions, it is easily deoxygenated to produce In2O or InO, which affects the conductivity, uniformity of components and structure, and density of the IGZO target, and further impacts the film deposition quality of the target. [Overview of the Initiative]

[0004] The objective of the present invention is to provide a MOS target, a method for manufacturing the same, and a thin-film transistor in order to solve the problems present in conventional IGZO targets, such as poor stability of electrical properties, susceptibility to deoxygenation during the sintering process, and the impact on the conductivity, uniformity of components and structure, and density of the target.

[0005] To achieve the above objectives, the technical solutions employed in this invention are as follows. In a first aspect, the present invention relates to a method for manufacturing a MOS target material, The steps involve co-precipitation of a mixed salt solution of three types of ions (In, Ga, and Sn), a precipitating agent, and a complexing agent, followed by washing and concentration to obtain high-purity indium gallium tin hydroxide colloid. The steps include: hydrothermally reacting the high-purity indium gallium tin hydroxide colloid with an auxiliary agent, then washing and drying to obtain a first indium gallium tin oxide powder; The first indium gallium tin oxide powder is subjected to a calcination treatment to obtain a second indium gallium tin oxide powder, The steps include: mixing the second indium gallium tin oxide powder, a dispersant, an antifoaming agent, and pure water in a ball mill to obtain a slurry; The steps include: obtaining a molded body by casting the slurry; The steps include: obtaining a MOS target by sintering the molded body under high-oxygen conditions; The present invention provides a manufacturing method that includes the following:

[0006] Selectively, the manufacturing method is The oxygen content of the second indium gallium tin oxide powder is lower than the oxygen content of the MOS target; The primary particle size of the first indium gallium tin oxide powder is 0.05 to 0.1 μm; The particle size of the second indium gallium tin oxide powder is 0.2 to 0.5 μm; It satisfies at least one of the following conditions.

[0007] Selectively, the manufacturing method is The step of preparing a mixed salt solution of three types of ions, In, Ga, and Sn, includes adding an indium salt, a gallium salt, and a tin salt to pure water and stirring uniformly to obtain a mixed salt solution of three types of ions, In, Ga, and Sn; The coprecipitation reaction must take place at a temperature of 50-65°C, for 6-8 hours, and at a pH of 8.5-9.5. The precipitating agent is selected from ammonia water or sodium hydroxide; The complexing agent is selected from ammonium nitrate or ammonium chloride; It satisfies at least one of the following conditions.

[0008] Selectively, the temperature of the hydrothermal reaction is 150-250°C, and the duration is 12-24 hours.

[0009] Selectively, the mass ratio of the high-purity indium gallium tin hydroxide colloid to the auxiliary agent is (1-2):(0.01-0.05).

[0010] Selectively, the adjuvant is one selected from sucrose, glucose, or fructose.

[0011] Selectively, the atmosphere for the calcination treatment is an argon-hydrogen mixed gas with a volume ratio of argon to hydrogen of (95-99):(1-5), a temperature of 600-800°C, and a duration of 4-10 hours.

[0012] Optionally, the mass ratio of In, Ga, and Sn in the second indium gallium tin oxide powder t is (34.7 to 67.4):(1.5 to 27.5):(13.0 to 16.5).

[0013] Optionally, the solid content of the slurry is 60 to 70%.

[0014] Optionally, the addition amount of the dispersant is 0.1 to 1% of the mass of the second indium gallium tin oxide powder, and / or the addition amount of the defoaming agent is 0.1 to 0.5% of the mass of the second indium gallium tin oxide powder.

[0015] Optionally, the dispersant is at least one selected from polyethylene glycol, hexadecyl sulfonate, polycarboxylate, polyacrylate, or triethanolamine, and / or the defoaming agent is selected from polyether-based defoaming agents and / or higher alcohols.

[0016] Optionally, the step of sintering the molded body under high oxygen conditions is loading the molded body into an alumina sleeve and then putting it into a sintering furnace, and then evacuating the alumina sleeve until the degree of vacuum reaches 10 -2 ~10 -3 Pa, at which point oxygen gas is started to be introduced, the oxygen pressure of the alumina sleeve is set to 0.05 to 0.1 MPa, and then the temperature is raised to 1400 to 1600 °C and kept warm and sintered for 12 to 48 h.

[0017] Optionally, the relative density of the MOS target material is ≧98.5% and the resistivity is ≦10 mΩ·cm.

[0018] As a second aspect, the present invention provides a MOS target including a MOS target manufactured by the manufacturing method of the MOS target provided by the present invention.

[0019] In a third aspect, the present invention provides a thin-film transistor comprising an active layer thin film obtained by sputtering using a MOS target provided in the present invention.

[0020] Compared to conventional technology, the present invention has the following beneficial effects. (1) A mixed salt solution of three ions, In, Ga, and Sn, is subjected to a coprecipitation reaction to obtain high-purity indium gallium tin hydroxide colloid. Then, by adding an auxiliary agent and carrying out a hydrothermal reaction, a first indium gallium tin oxide powder in which each component is uniformly distributed can be obtained. Furthermore, slight deoxygenation is achieved, and the particle size of the powder is increased by calcination, making molding easier, improving the density and strength of the molded body, and contributing to the improvement of the target density. By controlling the calcination conditions, the oxygen content of the generated second indium gallium tin oxide powder can be controlled more precisely and a slight deoxygenated state can be maintained, preventing In2O3 from being deoxygenated during the sintering process of the molded body to produce low-valence indium oxide (e.g., In2O or InO), which would affect the conductivity and oxygen content of the target. Therefore, compared to the air sintering method under atmospheric pressure that is normally used for mixed powders of indium oxide, gallium oxide, and tin oxide, the sintering process of the present invention is simpler in reaction, has better uniformity of target components and structure, is free from segregation, has high density, and has high conductivity. (2) Compared to IGZO targets, the MOS targets of the present invention do not contain ZnO, thus avoiding the problem that ZnO is sensitive to temperature, water vapor, etc., and easily affects the sustained operation and electrical stability of TFTs. On the other hand, Sn can increase the carrier concentration and improve the conductivity of the target. 4+ The ionic radius of is In 3+ This allows for the formation of high-mobility channels, which contributes to improving the mobility of the TFT. [Brief explanation of the drawing]

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that may be used in the description of the embodiments or the prior art are briefly described below. Obviously, the drawings in the following description are only a few embodiments of the present invention, and those skilled in the art can obtain other drawings based on these without any creative effort. [Figure 1] This is a process flow of the method for manufacturing a MOS target provided in an embodiment of the present invention. [Figure 2] This is an SEM image of the MOS target manufactured in Example 1 of the present invention. [Modes for carrying out the invention]

[0022] To further clarify the technical problems, technical solutions, and beneficial effects that the present invention aims to solve, the present invention will be described in more detail below with reference to examples. It should be understood that the specific embodiments described herein are for illustrative purposes only and do not limit the present invention.

[0023] In the embodiments of the present invention, the MOS target refers to a metal oxide semiconductor target, and specifically to an IGTO target.

[0024] As a first embodiment of the present invention, a method for manufacturing a MOS target is provided. As shown in Figure 1, it includes the following steps. S01: A mixed salt solution of three types of ions (In, Ga, and Sn), a precipitating agent, and a complexing agent are co-precipitated, washed, and concentrated to obtain high-purity indium gallium tin hydroxide colloid. S02: High-purity indium gallium tin hydroxide colloid and an auxiliary agent are subjected to a hydrothermal reaction, then washed and dried to obtain a first indium gallium tin oxide powder. S03: The first indium gallium tin oxide powder is calcined to obtain the second indium gallium tin oxide powder. S04: A slurry is obtained by ball-milling indium gallium tin oxide powder, a dispersant, an antifoaming agent, and pure water. S05: Cast the slurry to form a formed body. S06: Sinter the formed body under high oxygen conditions to obtain a MOS target.

[0025] In the method for manufacturing a MOS target provided in an embodiment of the present invention, after a co-precipitation reaction of a mixed salt solution of three kinds of ions of In, Ga, and Sn is performed to obtain a high-purity indium gallium tin hydroxide colloid, an auxiliary agent is added and a hydrothermal reaction is carried out, whereby a first indium gallium tin oxide powder in which each component is uniformly distributed can be obtained. Further, it is slightly deoxidized, and by further increasing the particle size of the powder by firing, molding is facilitated, the density and strength of the formed body are improved, which contributes to the improvement of the density of the target. By controlling the firing conditions, the oxygen content of the second indium gallium tin oxide powder to be generated can be more accurately controlled and a slightly deoxidized state can be maintained, and it is possible to prevent In2O3 from being deoxidized to generate a low-valence indium oxide (for example, In2O or InO) in the sintering process of the formed body, which affects the conductivity and oxygen content of the target. Therefore, compared with the atmospheric pressure air sintering method used for a mixed powder of ordinary indium oxide, gallium oxide and tin oxide, the sintering process of the present invention has a simple reaction, good uniformity of the components and structure of the target, no segregation, high density and high conductivity. (2) Compared with an IGZO target, since the MOS target of the present invention does not contain ZnO, it avoids the problem that ZnO is sensitive to temperature, water vapor, etc. and is likely to affect the continuous operation and electrical stability of the TFT. On the other hand, Sn can increase the carrier concentration and improve the conductivity of the target. Further, the ionic radius of Sn 4+ is closer to that of In 3+ and is likely to form a high-mobility channel, which contributes to the improvement of the mobility of the TFT.

[0026] In the embodiment, step S01 above, the step of preparing a mixed salt solution of three types of ions, In, Ga, and Sn, includes adding an indium salt, a gallium salt, and a tin salt to pure water and stirring uniformly to obtain a mixed salt solution of three types of ions, In, Ga, and Sn. The mass ratio of In, Ga, and Sn in the mixed salt solution is (34.7~67.4):(1.5~27.5):(13.0~16.5), the indium salt is selected from InCl3 powder, the gallium salt is selected from GaCl3 powder, and the tin salt is selected from SnCl4·5H2O.

[0027] In the examples, the coprecipitation reaction temperature was 50-65°C, the duration was 6-8 hours, and the pH value was 8.5-9.5.

[0028] In the examples, the precipitating agent is selected from aqueous ammonia or sodium hydroxide, and the complexing agent is selected from ammonium nitrate or ammonium chloride.

[0029] In the example, in step S02 above, the temperature of the hydrothermal reaction is 150-250°C and the time is 12-24 hours. Under hydrothermal conditions, the auxiliary agent exerts a reducing effect, slightly deoxygenating the resulting first indium gallium tin oxide powder. This is advantageous in preventing the impact on the conductivity of the target by preventing the deoxygenation of In2O3 in the subsequent sintering process, which generates In2O or InO. The phase transition is simple, which is advantageous in improving the uniformity of the target structure. Furthermore, the hydrothermal reaction avoids the occurrence of hard agglomeration of powder due to conventional mechanical milling, improving the uniformity and dispersibility of the powder, increasing the sintering activity of the powder, and contributing to improved purity, structural uniformity, and density of the MOS target.

[0030] In the examples, the mass ratio of high-purity indium gallium tin hydroxide colloid to the additive is (1-2):(0.01-0.05). Here, the additive is selected from sucrose, glucose, fructose, etc.

[0031] In the examples, the primary particle size of the first indium gallium tin oxide powder is 0.05 to 0.1 μm.

[0032] In the embodiment, in step S03 above, the atmosphere for the firing process is an argon-hydrogen mixed gas with a volume ratio of argon to hydrogen (95-99):(1-5), the temperature is 600-800°C, and the time is 4-10 hours. These firing conditions are favorable for the growth and particle size increase of the first indium gallium tin oxide powder, facilitate subsequent molding, allow for more precise control of the oxygen content of the resulting second indium gallium tin oxide powder, and maintain a slightly deoxygenated state.

[0033] In the example, the mass ratio of In, Ga, and Sn in the second indium gallium tin oxide powder is (34.7~67.4):(1.5~27.5):(13.0~16.5).

[0034] In this example, the oxygen content of the second indium gallium tin oxide powder is lower than that of the MOS target. This is advantageous in preventing the second indium gallium tin oxide powder from being deoxygenated in the subsequent sintering process, which would then produce In2O or InO and affect the conductivity and density of the target.

[0035] In the examples, the particle size of the second indium gallium tin oxide powder is 0.2 to 0.5 μm, and this particle size range is advantageous for powder casting, providing density and strength to the molded article.

[0036] In the embodiment, step S04 above, the step of ball-milling the second indium gallium tin oxide powder, dispersant, defoamer and pure water, includes placing the second indium gallium tin oxide powder, dispersant, defoamer and pure water into a ball-mill tank and ball-milling at a rotational speed of 200 to 1000 rpm for 6 to 18 hours to obtain a slurry.

[0037] In the examples, the solid content of the slurry is 60-70%.

[0038] In the examples, the amount of dispersant added is 0.1 to 1% of the mass of the indium gallium tin oxide powder. Specifically, the dispersant can be selected from one or more of the following: polyethylene glycol, hexadecyl sulfonate, polycarboxylate, polyacrylate, or triethanolamine.

[0039] In the examples, the amount of defoaming agent added is 0.1 to 0.5% of the mass of the indium gallium tin oxide powder. Specifically, the defoaming agent can be selected from polyether-based defoaming agents and / or higher alcohols.

[0040] In the embodiment, in step S05 described above, the step of casting the slurry involves placing the slurry in a vacuum tank, degassing it under vacuum, and then injecting the slurry into the cavity of a sealed resin or graphite mold at a pressure of 0.2 to 1.5 MPa. The injection continues until no more water droplets come out of the mold, the mold is opened, the hardened molded body is removed, and the body is left to stand at room temperature, i.e., 20°C to 25°C, for 24 hours to obtain the molded body.

[0041] In the embodiment, the step of sintering the molded body under high-oxygen conditions in step S06 above includes the following: that is, the molded body is placed in an alumina sleeve and then placed in a sintering furnace, and then the alumina sleeve is evacuated to a vacuum level of 10 -2 ~10 -3When the pressure reaches Pa, oxygen gas is introduced to set the oxygen pressure in the alumina sleeve to 0.05-0.1 MPa, and then the temperature is raised to 1400-1600°C for 12-48 hours of heat sintering. In this embodiment, placing the molded body inside the alumina sleeve before placing it in the sintering furnace and sintering the molded body in a narrow space is advantageous for precisely controlling the uniformity of the airflow and temperature, suppressing heat exchange between the molded body and the furnace chamber, reducing temperature fluctuations, heating the molded body more uniformly, reducing deformation or cracking due to thermal stress, improving the uniformity of the target structure, and ensuring that the airflow and temperature fields are the same during sintering for different production batches, resulting in stable and reproducible performance of the produced targets. Furthermore, controlling the oxygen pressure in the alumina sleeve allows the molded body to be sintered under high-oxygen conditions, which is advantageous for the slightly deoxygenated indium gallium tin oxide powder to be sufficiently oxidized, forming a target with uniform composition and structure and good conductivity, and preventing the deoxygenation of In2O3 in the powder to produce In2O, which would affect the conductivity and density of the target. Furthermore, the use of alumina sleeves reduces the amount of oxygen gas used, thereby lowering costs.

[0042] In the embodiment, the MOS target has a relative density of ≥98.5% and a resistivity of ≤10 mΩ·cm.

[0043] As a second embodiment of the present invention, a MOS target is provided which includes a MOS target manufactured by the method for manufacturing a MOS target provided in the present invention.

[0044] The MOS targets provided in the embodiments of the present invention are manufactured by the method for manufacturing MOS targets provided in the embodiments of the present invention, and therefore have advantages such as high density, good uniformity of components and structure, low resistivity, and good stability.

[0045] As a third embodiment of the present invention, a thin-film transistor is provided which includes an active layer thin film obtained by sputtering using a MOS target provided in the present invention.

[0046] The thin-film transistors provided in the embodiments of the present invention have advantages such as low resistivity, high carrier concentration, high mobility, and good stability against water, oxygen, light, and heat, because their active layer thin film is obtained by sputtering using a metal oxide semiconductor target provided in the embodiments of the present invention. As a result, they improve performance indicators such as the mobility, threshold voltage, and current on / off ratio of the TFT, alleviate reliability problems due to long-term operation of the TFT, extend the lifespan of the TFT, contribute to the realization of high resolution, high refresh rate, low power consumption, and high resolution in displays, and improve the stability of the display.

[0047] The following will explain the process with reference to specific examples.

[0048] Example 1 This embodiment provides a method for manufacturing a MOS target, and includes the following steps. S11: Appropriate amounts of InCl3 powder, GaCl3 powder, and SnCl4·5H2O were weighed so that the mass ratio of In, Ga, and Sn was 37.6:27.5:14.3. These were added to pure water and mixed uniformly to obtain a mixed salt solution of the three ions: In, Ga, and Sn. The mixed salt solution of the three ions, sodium hydroxide solution, and aqueous ammonia solution were added to the reaction vessel and mixed. The temperature of the reaction vessel was controlled to 60°C, and the pH value of the reaction system was controlled to 9. The coprecipitation reaction was carried out for 7 hours, and after washing and concentration, high-purity indium gallium tin hydroxide colloid was obtained. S12: Using a mass ratio of 1.5:0.03, an appropriate amount of high-purity indium gallium tin hydroxide colloid and glucose were weighed and added to pure water, and mixed uniformly to obtain a suspension (concentration 0.5 mol / L). The suspension was transferred to the liner of the reaction vessel, and an appropriate amount of pure water was added so that the final volume of the suspension was 70% of the volume of the liner of the reaction vessel. The reaction vessel was placed in a dry box at 200°C, and the hydrothermal reaction was carried out for 18 hours. After that, the precipitate obtained by centrifugation was repeatedly washed with pure water and anhydrous ethanol, respectively, and dried to obtain primary indium gallium tin oxide powder (measured result, average particle size D50 = 0.08 μm). S13: Place the first indium gallium tin oxide powder into the atmosphere sintering furnace, 10-2 After evacuating to Pa, an argon-hydrogen mixed gas (argon to hydrogen volume ratio 98:2) was introduced, the temperature was raised to 750°C, and the mixture was heated and fired for 6 hours to obtain indium gallium tin oxide powder (measured to have an average particle size D50 = 0.35 μm). S14: Indium gallium tin oxide powder, polyethylene glycol, polyoxypropylene glyceryl ether, and pure water were placed in a ball mill tank and ball milled at a rotation speed of 500 rpm for 12 hours to obtain a slurry (solid content 65%). The amount of polyethylene glycol added was 0.5% of the mass of indium gallium tin oxide powder, and the amount of polyoxypropylene glyceryl ether added was 0.3% of the mass of indium gallium tin oxide powder. S15: The slurry was placed in a vacuum tank, degassed under vacuum, and then injected into the cavity of a sealed graphite mold at a pressure of 1 MPa. Injection continued until no more water droplets came out of the mold, the mold was opened, the hardened molded body was removed, and the body was left to stand at room temperature for 24 hours to obtain the molded body. S16: After the molded body is placed in the alumina sleeve, it is placed in the sintering furnace, and then the alumina sleeve is evacuated to a vacuum level of 5 × 10 -2 When the pressure reached Pa, oxygen gas was introduced to raise the oxygen pressure in the alumina sleeve to 0.08 MPa. Then, the temperature was raised to 1500°C and sintered for 36 hours to obtain the MOS target.

[0049] Comparative Example 1 This comparative example provides a method for manufacturing a MOS target. The differences from Example 1 are as follows. Step S12 was not performed. In step S13, high-purity indium gallium tin hydroxide colloid was placed in a sintering furnace, heated to 750°C under an air atmosphere, and fired for 6 hours to obtain a second indium gallium tin oxide powder (measured to have an average particle size D50 = 0.41 μm).

[0050] Comparative Example 2 This comparative example provides a method for manufacturing a MOS target. The differences from Example 1 are as follows. Step S13 was not performed. In step S14, the primary indium gallium tin oxide powder, polyethylene glycol, polyoxypropylene glyceryl ether, and pure water were added to the ball mill tank.

[0051] Comparative Example 3 This comparative example provides a method for manufacturing a MOS target. The differences from Example 1 are as follows. In step S15, the molded body is placed in the sintering furnace, and then the sintering furnace is evacuated to a vacuum level of 5 × 10 -2 When the temperature reached Pa, oxygen gas was introduced, and then the temperature was raised to 1500°C and sintered for 36 hours to obtain the MOS target.

[0052] Comparative Example 4 This comparative example provides a method for manufacturing an MOS target, and includes the following steps. S1: Appropriate amounts of indium oxide powder, gallium oxide powder, and tin oxide powder were weighed so that the mass ratio of indium, gallium, and tin was 37.6:27.5:14.3. S2: Indium oxide powder, gallium oxide powder, tin oxide powder, polyethylene glycol, polyoxypropylene glyceryl ether, and pure water were placed in a ball mill tank and ball milled at a rotation speed of 500 rpm for 12 hours to obtain a slurry. S3: The slurry was placed in a vacuum tank, degassed under vacuum, and then injected into the cavity of a sealed graphite mold at a pressure of 1 MPa. Injection continued until no more water droplets came out of the mold, the mold was opened, the cured molded body was removed, and the body was left to stand at room temperature for 24 hours to obtain the molded body. S4: The molded body is placed in the sintering furnace, and then the sintering furnace is evacuated to a vacuum level of 5 × 10 -2 When the temperature reached Pa, oxygen gas was introduced, and then the temperature was raised to 1500°C and sintered for 36 hours to obtain the MOS target.

[0053] Related Performance Test Analysis 1. After encapsulating the MOS targets with resin, the density of the MOS targets manufactured in Example 1 and Comparative Examples 1-4 was tested using the Archimedes density test. Specifically, the MOS targets were evenly cut into five segments along their cross-section, and the actual density of each segment was measured. The relative density was calculated as follows: Relative density = Actual density / Theoretical density × 100%, with the theoretical density as the reference. The test results are shown in Table 1 below. 2. The resistivity of the MOS targets obtained in Example 1 and Comparative Examples 1-4 was measured using a four-probe probe. Specifically, the resistivity of five different regions of the MOS target material was measured, and the measurement results are shown in Table 2 below. 3. The oxygen content of the MOS targets obtained in Example 1 and Comparative Examples 1-4 was measured using an oxygen-nitrogen analyzer. Specifically, five samples were cut from different regions of the MOS target, and the oxygen content of each sample was measured. The measurement results are shown in Table 3 below. Here, median uniformity = [(max-min)÷(max+min)] × 100%.

[0054] [Table 1]

[0055] [Table 2]

[0056] [Table 3]

[0057] As can be seen from Tables 1 and 2, the targets manufactured in Example 1 all had a relative density greater than 99.0% and a resistivity of less than 3 mΩ·cm. This demonstrates that high-density and low-resistivity MOS targets can be manufactured by the manufacturing method of the embodiment of the present invention.

[0058] The relative density of the target produced in Example 1 was significantly higher than that of Comparative Examples 3 and 4, and the uniformity of the relative density (based on the median) of the target produced in Example 1 was significantly lower than that of Comparative Examples 3 and 4. This is mainly because, in the examples of the present invention, by placing the molded body in an alumina sleeve and performing high-oxygen sintering, the uniformity of the airflow and temperature can be precisely controlled, allowing the molded body to be heated uniformly. This improves the uniformity of the density and structure of the target, and makes its density distribution more uniform.

[0059] The relative density of Comparative Example 1 was lower than that of Example 1. The main reason for this is that in Comparative Example 1, the high-purity indium gallium tin hydroxide colloid produced by the coprecipitation reaction was directly calcined in air, making it impossible to adjust the oxygen content of the indium gallium tin oxide powder. This resulted in oxygen deficiency in In2O3 during subsequent sintering, leaving voids, which is unfavorable for forming a highly dense target. The relative density of Comparative Example 2 was also lower than that of Example 1. The main reason for this is that in Comparative Example 2, the particle size of the powder produced by the hydrothermal reaction was too fine, which is unfavorable for casting and unfavorable for forming a highly dense target.

[0060] The resistivity and median resistivity uniformity of the target produced in Example 1 were both significantly lower than those of Comparative Examples 1-2 and Comparative Example 4. This is mainly because, in the examples of the present invention, a combination of coprecipitation, hydrothermal reaction, and calcination is performed, and by adding glucose and high-purity indium gallium tin hydroxide colloid and carrying out the hydrothermal reaction, the resulting first indium gallium tin oxide powder is slightly deoxygenated. Furthermore, by calcining the first indium gallium tin oxide powder in an argon-hydrogen mixed atmosphere, the oxygen content of the powder can be more precisely controlled to maintain a slightly deoxygenated state. This allows for sufficient oxidation to stable In2O3 in the subsequent high-oxygen sintering, and the resistivity of the target is lower because it avoids the influence of low-valence indium-doped oxides (e.g., InO or In2O) on the conductive performance.

[0061] The resistivity and resistivity uniformity (based on the median) of the target manufactured in Example 1 were lower than those of Comparative Example 3. The main reason for this is that, in the examples of the present invention, by placing the molded body into an alumina sleeve and then sintering it in a sintering furnace, the temperature and airflow can be precisely controlled, allowing the molded body to be heated more uniformly. As a result, the uniformity of the target's components and structure is better, and its resistivity is lower.

[0062] As can be seen from Table 3, the oxygen content in each region of the target manufactured in Example 1 was 20.3 to 20.6, which is close to the theoretical value (20.6), and the uniformity of oxygen content (based on the median) was relatively small. On the other hand, the oxygen content in each region of the targets manufactured in Comparative Examples 1 and 2 was clearly lower than the theoretical value, and the uniformity of oxygen content (based on the median) was relatively large. This is mainly because, in the examples of the present invention, the oxygen content of the second indium gallium tin oxide powder is precisely controlled by combining coprecipitation, hydrothermal reaction, and calcination, and slight deoxygenation reduces the effect of the deoxygenation state of In2O3 in the molded body on the oxygen content of the target during the high-oxygen sintering process.

[0063] As can be seen from the SEM in Figure 2, the MOS target fabricated in Example 1 had uniform grains, tight inter-grain bonding, and no distinct grain boundaries or pores.

[0064] As can be seen from the above, the method for manufacturing a MOS target provided in the embodiments of the present invention makes it possible to successfully manufacture a MOS target with good uniformity of components and structure, high density, good conductivity, and stable electrical properties. Therefore, a MOS thin film manufactured by sputtering using the MOS target of the present invention has advantages such as good uniformity, high carrier concentration, high mobility, ZnO-free content, and good stability against water, oxygen, light, and heat.

[0065] The foregoing are merely preferred embodiments of the present invention and do not limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are all included within the scope of protection of the present invention.

Claims

1. A method for manufacturing MOS target material, The process involves co-precipitation of a mixed salt solution of three types of ions (In, Ga, and Sn), a precipitating agent, and a complexing agent, followed by washing and concentration to obtain high-purity indium gallium tin hydroxide colloid. The first step is to obtain a first indium gallium tin oxide powder by hydrothermally reacting the high-purity indium gallium tin hydroxide colloid with an auxiliary agent, followed by washing and drying. The first indium gallium tin oxide powder is subjected to a calcination treatment to obtain a second indium gallium tin oxide powder, The steps include: mixing the second indium gallium tin oxide powder, a dispersant, an antifoaming agent, and pure water in a ball mill to obtain a slurry; The steps include: obtaining a molded body by casting the slurry; The steps include: obtaining a MOS target by sintering the molded body under high-oxygen conditions; A manufacturing method characterized by including the following.

2. The oxygen content of the second indium gallium tin oxide powder is lower than the oxygen content of the MOS target; The primary particle size of the first indium gallium tin oxide powder is 0.05 to 0.1 μm; The particle size of the second indium gallium tin oxide powder is 0.2 to 0.5 μm; The manufacturing method according to claim 1, characterized in that it satisfies at least one of the following conditions.

3. The step of preparing a mixed salt solution of three types of ions, In, Ga, and Sn, includes adding an indium salt, a gallium salt, and a tin salt to pure water and stirring uniformly to obtain a mixed salt solution of three types of ions, In, Ga, and Sn; The coprecipitation reaction is carried out at a temperature of 50-65°C, for 6-8 hours, and at a pH of 8.5-9.

5. The precipitating agent is selected from ammonia water or sodium hydroxide; The complexing agent is selected from ammonium nitrate or ammonium chloride; The manufacturing method according to claim 1, characterized in that it satisfies at least one of the following conditions.

4. The manufacturing method according to claim 1, characterized in that the temperature of the hydrothermal reaction is 150 to 250°C and the duration is 12 to 24 hours.

5. The manufacturing method according to claim 1, characterized in that the mass ratio of the high-purity indium gallium tin hydroxide colloid to the auxiliary agent is (1-2):(0.01-0.05).

6. The manufacturing method according to claim 1, characterized in that the aforementioned auxiliary agent is one selected from sucrose, glucose, or fructose.

7. The manufacturing method according to claim 1, characterized in that the atmosphere for the firing treatment is an argon-hydrogen mixed gas with a volume ratio of argon to hydrogen of (95-99):(1-5), the temperature is 600-800°C, and the time is 4-10 hours.

8. The manufacturing method according to claim 1, characterized in that the mass ratio of In, Ga, and Sn in the second indium gallium tin oxide powder is (34.7 to 67.4):(1.5 to 27.5):(13.0 to 16.5).

9. The manufacturing method according to claim 1, characterized in that the solid content of the slurry is 60 to 70%.

10. The amount of the dispersant added is 0.1 to 1% of the mass of the second indium gallium tin oxide powder, and / or The manufacturing method according to claim 1, characterized in that the amount of the defoaming agent added is 0.1 to 0.5% of the mass of the second indium gallium tin oxide powder.

11. The dispersant is at least one selected from polyethylene glycol, hexadecyl sulfonate, polycarboxylate, polyacrylate, or triethanolamine, and / or The manufacturing method according to claim 1, characterized in that the defoaming agent is selected from a polyether-based defoaming agent and / or a higher alcohol.

12. The step of sintering the molded body under high-oxygen conditions is: The molded body is placed in an alumina sleeve and then placed in a sintering furnace. After that, the alumina sleeve is evacuated until the vacuum level reaches 10. －２ ~10 －３ A manufacturing method according to any one of claims 1 to 11, characterized in that oxygen gas is introduced when the pressure reaches Pa, the oxygen pressure of the alumina sleeve is set to 0.05 to 0.1 MPa, the temperature is then raised to 1400 to 1600°C, and the material is sintered while holding heat for 12 to 48 hours.

13. The manufacturing method according to claim 12, characterized in that the MOS target material has a relative density of ≥ 98.5% and a resistivity of ≤ 10 mΩ·cm.

14. A MOS target comprising a MOS target manufactured by the manufacturing method described in any one of claims 1 to 13.

15. A thin-film transistor including an active layer thin film, The thin-film transistor is characterized in that the active layer thin film is obtained by sputtering using the MOS target described in claim 14.

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