Method for producing a tantalum-doped tin oxide target for rpd thin films

Abstract

The application discloses a preparation method of a tantalum-doped tin oxide target material for an RPD thin film, which comprises the following steps: S1, tin oxide, tantalum oxide, a dispersing agent and deionized water are mixed according to a set proportion by one-time ball milling to obtain a first mixed slurry; S2, the first mixed slurry is dried, and then is crushed into powder, and powder with a particle size less than 80-200 mesh is selected; S3, the powder obtained in the step S2 is subjected to calcination treatment, and calcined powder is collected; S4, the calcined powder, a binder, a dispersing agent and deionized water are mixed according to a set proportion by second-time ball milling to obtain a second slurry; S5, the second slurry is subjected to spray granulation to obtain spherical granular powder; S6, the spherical granular powder is subjected to die compaction to obtain a target blank; S7, the target blank is subjected to isostatic pressing to obtain a low-density target blank; and S8, the low-density target blank is subjected to sintering to obtain the tantalum-doped tin oxide target material for the RPD thin film.

Description

Technical Field

[0001] This invention belongs to the field of inorganic material preparation technology, specifically relating to a method for preparing tantalum oxide-doped tin oxide target for RPD thin films. Background Technology

[0002] In recent years, the flat panel display industry worldwide has flourished alongside the widespread adoption of smart appliances. Transparent conductive oxide (TCO) films, as channel layer materials for thin-film transistors (TFTs), have received extensive research and attention. TCO films, due to their narrow bandgap, low resistivity, high transmittance, and high reflectivity in the infrared spectral region, have wide applications in solar cells, flat panel displays, organic light-emitting diodes (OLEDs), photodetectors, transparent TFTs, and flexible electronic devices. Indium tin oxide (ITO) is the most widely used, but indium is easily reduced in hydrogen plasma environments, leading to a decrease in film conductivity. Furthermore, the drastic reduction in natural indium reserves has caused its price to rise, and indium itself is toxic, making it unsuitable for meeting market demand. Therefore, finding new thin-film materials is extremely important.

[0003] Tin dioxide (SnO2) is a wide-bandgap semiconductor oxide with high electron mobility, considered a potential candidate for total organic carbon (TCO) materials, exhibiting a rutile structure. Undoped SnO2 is optically transparent in the visible light range but lacks the conductivity required to be a transparent conductor. Tantalum is considered an excellent doping source for SnO2, and tin tantalum oxide (TTO) targets have significantly higher conductivity than pure SnO2.

[0004] Reactive plasma deposition (RPD) is a technique for depositing thin films on substrates using a pressure-slope plasma ion gun. This method offers advantages such as minimal ion damage, low deposition temperature, large deposition area, and rapid growth. RPD devices can generate stable and uniform plasma, with very few energy particles above 50 eV, minimizing their impact on substrate corrosion. TCO films prepared using RPD exhibit advantages such as dense structure, high crystallinity, good conductivity, and good light transmittance. The target material, as the core material for TCO film preparation, is crucial to the film quality, which in turn affects the manufacturing quality and performance of the device. Summary of the Invention

[0005] In view of this, some embodiments disclose a method for preparing tantalum oxide-doped tin oxide target materials for RPD thin films, including the following steps:

[0006] S1, tin oxide, tantalum oxide, dispersant, and deionized water are ball-milled and mixed in a set ratio to obtain a primary slurry.

[0007] S2. Dry the mixed slurry and then pulverize it into powder, selecting powder with a particle size of less than 80-200 mesh;

[0008] S3. The powder obtained in step S2 is calcined, and the calcined powder is collected.

[0009] S4. The calcined powder, binder, dispersant and deionized water are ball-milled and mixed in a set ratio to obtain a secondary slurry;

[0010] S5. Spray granulation of the secondary slurry to obtain spherical granular powder;

[0011] S6. Spherical granular powder is molded to obtain the target material blank;

[0012] S7. The target blank is subjected to isostatic pressing to obtain a low-density target blank with a relative density of 50-65%.

[0013] S8. The low-density target blank is sintered to obtain a tantalum oxide-doped tin oxide target for RPD thin films.

[0014] Furthermore, in some embodiments, the method for preparing tantalum oxide-doped tin oxide target material for RPD thin films discloses that, in step S1, the mass ratio of tin oxide to tantalum oxide is 90-99:1-10, the mass content of deionized water in the primary mixing slurry is 50-70%, and the mass content of dispersant is 0.25-1.5%.

[0015] Some embodiments disclose a method for preparing tantalum oxide-doped tin oxide target material for RPD thin films. In step S1, a ball milling mixture is carried out in a ball mill with the ball mill speed set to 280-350 r / min, the ball-to-material ratio to be 3:1, and the ball milling time to be 4-18 hours. The ball milling ends when the D50 of the mixed slurry is 0.3-0.7 μm.

[0016] In some embodiments, a method for preparing tantalum oxide-doped tin oxide target for RPD thin films is disclosed. In step S3, the calcination temperature is 950–1500°C and the calcination time is 2–8 h.

[0017] In some embodiments, a method for preparing tantalum oxide-doped tin oxide target for RPD thin films is disclosed. In step S4, the mass content of dispersant in the secondary slurry is 0.5-2%, the mass content of deionized water is 50-70%, and the mass content of binder is 0.5-2%.

[0018] Some embodiments disclose a method for preparing tantalum oxide-doped tin oxide targets for RPD thin films. In step S4, secondary ball milling mixing is performed in a ball mill, including:

[0019] The calcined powder, dispersant and deionized water are mixed in a second ball mill according to a set ratio. The ball mill speed is set to 280-360 r / min, the ball-to-material ratio is 3:1, and the ball milling time is 12-25 hours.

[0020] Then add the binder and continue ball milling for 1.5 to 4 hours.

[0021] In some embodiments, a method for preparing tantalum oxide-doped tin oxide targets for RPD thin films is disclosed. In step S5, the spray granulation temperature is 195–225°C, the feed rate is 5–15 ml / min, and the centrifuge frequency is 30–50 Hz.

[0022] In some embodiments, a method for preparing tantalum oxide-doped tin oxide targets for RPD thin films is disclosed. In step S6, the molding pressure is 30-50 MPa and the holding time is 3-10 min.

[0023] In some embodiments, a method for preparing tantalum oxide-doped tin oxide targets for RPD thin films is disclosed. In step S7, the isostatic pressure is 100-300 MPa, and the holding time is 3-30 min.

[0024] In some embodiments, a method for preparing tantalum oxide-doped tin oxide targets for RPD thin films is disclosed. In step S8, the sintering temperature is 1100–1600°C and the sintering time is 3–12 hours.

[0025] The present invention discloses a method for preparing tantalum oxide-doped tin oxide targets for RPD thin films. By controlling the calcination and sintering temperatures, a tantalum oxide-doped tin oxide target with controllable density is obtained, ensuring a uniform target structure and improving the quality of the RPD thin film. The relative density of the target can be precisely controlled between 60% and 73% according to actual needs. When used as a target for preparing TCO coatings using the RPD method, the tantalum oxide-doped tin oxide target can improve the uniformity of the TCO coating and enhance its quality and performance, showing promising application prospects. Attached Figure Description

[0026] Figure 1 Example 1: XRD pattern of tantalum oxide-doped tin oxide target;

[0027] Figure 2 Example 1: SEM image of tantalum oxide-doped tin oxide target. Detailed Implementation

[0028] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in these embodiments of the invention, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in these embodiments is merely for describing particular implementations and is not intended to limit the scope of the disclosure of these embodiments.

[0029] Unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this invention pertain; other experimental methods and technical means not specifically noted in the embodiments of this invention refer to experimental methods and technical means commonly used by one of ordinary skill in the art.

[0030] The terms “basic” and “approximately” used in this document are to describe small fluctuations. For example, they can mean less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data presented or expressed in range format in this document are used for convenience and brevity only, and should therefore be flexibly interpreted to include not only the explicitly listed values ​​that define the range, but also all independent values ​​or subranges contained within that range. For example, a numerical range of “1–5%” should be interpreted to include not only the explicitly listed values ​​from 1% to 5%, but also the independent values ​​and subranges within the indicated range. Thus, this numerical range includes independent values ​​such as 2%, 3.5%, and 4%, and subranges such as 1%–3%, 2%–4%, and 3%–5%, etc. This principle also applies to ranges that list only one value. Furthermore, this interpretation applies regardless of the width of the range or the characteristics described.

[0031] In this document, including in the claims, conjunctions such as "comprising," "including," "with," "having," "containing," "involving," and "accommodating" are understood to be open-ended, meaning "including but not limited to." Only the conjunctions "consisting of" and "composed of" are closed conjunctions.

[0032] To better illustrate the content of this invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that the invention can be practiced even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail, in order to highlight the main points of the invention.

[0033] Without conflict, the technical features disclosed in the embodiments of the present invention can be combined arbitrarily, and the resulting technical solution belongs to the content disclosed in the embodiments of the present invention.

[0034] In some embodiments, the method for preparing a tantalum oxide-doped tin oxide target for RPD thin films includes the steps of:

[0035] S1, tin oxide, tantalum oxide, dispersant, and deionized water are ball-milled and mixed in a set ratio to obtain a primary slurry.

[0036] The mass ratio of tin oxide to tantalum oxide is 90-99:1-10, the mass content of deionized water in the primary mixing slurry is 50-70%, and the mass content of dispersant is 0.25-1.5%.

[0037] The ball milling process is carried out in a ball mill with a speed of 280–350 r / min, a ball-to-material ratio of 3:1, and a milling time of 4–18 hours. The ball milling is stopped when the D50 of the mixed slurry is 0.3–0.7 μm.

[0038] S2. Dry the mixed slurry and then pulverize it into powder, selecting powder with a particle size of less than 80-200 mesh;

[0039] S3. The powder obtained in step S2 is subjected to calcination treatment, and the calcined powder is collected; the calcination temperature is 950-1500℃, and the calcination time is 2-8h.

[0040] S4. The calcined powder, binder, dispersant and deionized water are ball-milled and mixed in a set ratio to obtain a secondary slurry;

[0041] The secondary slurry contains 0.5-2% by mass of dispersant, 50-70% by mass of deionized water, and 0.5-2% by mass of binder.

[0042] Secondary ball milling and mixing are carried out in a ball mill, including:

[0043] The calcined powder, dispersant and deionized water are mixed in a second ball mill according to a set ratio. The ball mill speed is set to 280-360 r / min, the ball-to-material ratio is 3:1, and the ball milling time is 12-25 hours.

[0044] Then add the binder and continue ball milling for 1.5 to 4 hours;

[0045] S5. Spray granulation of the secondary slurry to obtain spherical granules; the spray granulation temperature is 195-225℃, the feed rate is 5-15ml / min, and the centrifuge frequency is 30-50Hz; usually, a certain amount of n-octanol defoamer can be added to the slurry before spray granulation to eliminate air bubbles in the slurry.

[0046] S6. Spherical granular powder is molded to obtain a target blank; the molding pressure is 30-50 MPa, and the holding time is 3-10 min.

[0047] S7. The target blank is subjected to isostatic pressing to obtain a low-density target blank; the isostatic pressing pressure is 100-300MPa, and the holding time is 3-30min; usually, the density of the target blank is further increased after isostatic pressing, and a low-density target blank with a relative density of 50-65% is obtained.

[0048] S8. The low-density target blank is sintered to obtain tantalum oxide-doped tin oxide target material for RPD thin films; the sintering temperature is 1100-1600℃, and the sintering time is 3-12 hours. RPD thin films generally refer to transparent conductive oxide thin films (TCOs) prepared by the RPD method.

[0049] The technical details are further illustrated below with reference to the embodiments.

[0050] Example 1

[0051] In Example 1, the method for preparing the tantalum oxide-doped tin oxide target for RPD thin films includes the following steps:

[0052] S1, tin oxide, tantalum oxide, dispersant, and deionized water are ball-milled and mixed in a set ratio to obtain a primary slurry. The mass ratio of tin oxide to tantalum oxide is 94:6, the mass content of deionized water in the primary slurry is 65%, and the dispersant is ammonium polyacrylate with a mass content of 1.2%. The primary ball milling is carried out in a ball mill with a speed of 330 r / min, a ball-to-material ratio of 3:1, and a milling time of 8 hours. The ball milling is stopped when the D50 of the slurry is less than 0.6 μm.

[0053] S2. Place the mixed slurry in an 80℃ oven to dry, then crush it into powder using an agate mortar and pestle, pass it through a 100-mesh sieve, and select powder with a particle size of less than 100 mesh.

[0054] S3. The powder obtained in step S2 is placed in a crucible and calcined in a muffle furnace at a temperature of 1150℃ for 3 hours. The calcined powder is then collected.

[0055] S4. The calcined powder, binder, dispersant and deionized water are ball-milled and mixed in a set ratio to obtain a secondary slurry; wherein, the dispersant in the secondary slurry is ammonium polyacrylate with a mass content of 1.2%, the deionized water has a mass content of 65%, and the binder is polyvinyl alcohol with a mass content of 1.2%.

[0056] The secondary ball milling mixing process takes place in a ball mill and specifically includes:

[0057] Calcined powder, dispersant and deionized water were mixed in a second ball mill according to a set ratio. The ball mill speed was set to 330 r / min, the ball-to-material ratio was 3:1, and the ball milling time was 18 hours.

[0058] Then add the binder and continue ball milling for 1.5 hours;

[0059] S5. The secondary slurry is spray-granulated using a spray granulator to obtain dry, free-flowing mixed spherical granules; the spray granulation temperature is 220℃, the feed rate is 12ml / min, and the centrifuge frequency is 50Hz.

[0060] S6. Spherical granular powder is placed in an alloy steel mold and molded to obtain a target blank; the molding pressure is 30 MPa and the holding time is 3 min.

[0061] S7. Completely cover the target blank with aluminum-silicon foil, vacuum seal it with a vacuum sealing machine, and then press it with isostatic pressing in an isostatic press to obtain a low-density target blank with a relative density of 55%; the isostatic pressing pressure is 200MPa and the holding time is 10min.

[0062] S8. The low-density target blank is sintered at a temperature of 1300℃ for 3 hours. After calcination, it is naturally cooled to room temperature to obtain tantalum oxide-doped tin oxide target for RPD thin film.

[0063] The density of the tantalum oxide-doped tin oxide target obtained in Example 1 is 4.221 g / cm³. 3 Its relative density is 60.3%. Figure 1 The XRD pattern of the tantalum oxide-doped tin oxide target shows that the main phase diffraction peaks are basically consistent, exhibiting a single tetragonal rutile structure of SnO2 (PDF#41-1445), and a relatively weak Ta2O5 (PDF#25-0922) diffraction peak. Meanwhile, Sn2Ta2O7 is dispersed as a second phase within the matrix phase. Figure 2 Here is a SEM image of a tantalum oxide-doped tin oxide target, as shown below. Figure 2 The tin oxide tantalum RPD target shown has a uniform grain structure, and the pores are evenly distributed inside the target, resulting in uniform and fine grains, which is convenient for industrial mass production.

[0064] Example 2

[0065] In Example 2, the method for preparing the tantalum oxide-doped tin oxide target for RPD thin films includes the following steps:

[0066] S1, tin oxide, tantalum oxide, dispersant, and deionized water are ball-milled and mixed in a set ratio to obtain a primary mixed slurry; wherein, the mass ratio of tin oxide to tantalum oxide is 90:10, the mass content of deionized water in the primary mixed slurry is 65%, and the dispersant is polyacrylic acid with a mass content of 1%.

[0067] The ball milling process was carried out in a ball mill with a speed of 350 r / min, a ball-to-material ratio of 3:1, and a milling time of 10 hours. The ball milling was stopped when the D50 of the mixed slurry was less than 0.6 μm.

[0068] S2. Place the mixed slurry in an 85℃ oven to dry, then crush it into powder using an agate mortar and pestle, pass it through a 120-mesh sieve, and select powder with a particle size of less than 120 mesh.

[0069] S3. The powder obtained in step S2 is placed in a crucible and calcined in a muffle furnace at a temperature of 1250℃ for 3 hours. The calcined powder is then collected.

[0070] S4. The calcined powder, binder, dispersant and deionized water are ball-milled and mixed in a set ratio to obtain a secondary slurry; wherein, the dispersant in the secondary slurry is ammonium polyacrylate with a mass content of 1.5%, the deionized water has a mass content of 68%, and the binder is polyvinyl alcohol with a mass content of 1.5%.

[0071] The secondary ball milling mixing process takes place in a ball mill and specifically includes:

[0072] Calcined powder, dispersant and deionized water were mixed in a second ball mill according to a set ratio. The ball mill speed was set to 350 r / min, the ball-to-material ratio was 3:1, and the ball milling time was 20 hours.

[0073] Then add the binder and continue ball milling for 2 hours;

[0074] S5. The secondary slurry is spray-granulated using a spray granulator to obtain dry, free-flowing mixed spherical granules; the spray granulation temperature is 210℃, the feed rate is 14ml / min, and the centrifuge frequency is 50Hz.

[0075] S6. Spherical granular powder is placed in an alloy steel mold and molded to obtain a target blank; the molding pressure is 35 MPa and the holding time is 4 min.

[0076] S7. Completely cover the target blank with aluminum-silicon foil, vacuum seal it with a vacuum sealing machine, and then press it with isostatic pressing in an isostatic press to obtain a low-density target blank with a relative density of 60%; the isostatic pressing pressure is 220MPa, and the holding time is 15min.

[0077] S8. The low-density target blank is sintered at a temperature of 1500℃ for 3 hours. After calcination, it is naturally cooled to room temperature to obtain tantalum oxide-doped tin oxide target for RPD thin film.

[0078] The density of the tantalum oxide-doped tin oxide target obtained in Example 2 is 4.6543 g / cm³. 3 Its relative density is 66.49%.

[0079] Example 3

[0080] In Example 3, the method for preparing the tantalum oxide-doped tin oxide target for RPD thin films includes the following steps:

[0081] S1, tin oxide, tantalum oxide, dispersant, and deionized water are ball-milled and mixed in a set ratio to obtain a primary mixed slurry; wherein, the mass ratio of tin oxide to tantalum oxide is 97:3, the mass content of deionized water in the primary mixed slurry is 60%, and the dispersant is polyacrylic acid with a mass content of 1.5%.

[0082] The ball milling process was carried out in a ball mill with a speed of 300 r / min, a ball-to-material ratio of 3:1, and a milling time of 12 hours. The ball milling was stopped when the D50 of the mixed slurry was less than 0.6 μm.

[0083] S2. Place the mixed slurry in a 90℃ oven to dry, then crush it into powder using an agate mortar and pestle, pass it through an 80-mesh sieve, and select powder with a particle size of less than 80 mesh.

[0084] S3. The powder obtained in step S2 is placed in a crucible and calcined in a muffle furnace at a temperature of 1350℃ for 3 hours. The calcined powder is then collected.

[0085] S4. The calcined powder, binder, dispersant and deionized water are ball-milled and mixed in a set ratio to obtain a secondary slurry; wherein, the dispersant in the secondary slurry is ammonium polyacrylate with a mass content of 1.5%, the deionized water has a mass content of 65%, and the binder is polyvinyl alcohol with a mass content of 1.5%.

[0086] The secondary ball milling mixing process takes place in a ball mill and specifically includes:

[0087] Calcined powder, dispersant and deionized water were mixed in a second ball mill according to a set ratio. The ball mill speed was set to 320 r / min, the ball-to-material ratio was 3:1, and the ball milling time was 20 hours.

[0088] Then add the binder and continue ball milling for 2.5 hours;

[0089] S5. The secondary slurry is spray-granulated using a spray granulator to obtain dry, free-flowing mixed spherical granular powder; the spray granulation temperature is 220℃, the feed rate is 15ml / min, and the centrifuge frequency is 40Hz.

[0090] S6. Spherical granular powder is placed in an alloy steel mold and molded to obtain a target blank; the molding pressure is 40 MPa and the holding time is 5 min.

[0091] S7. Completely cover the target blank with aluminum-silicon foil, vacuum seal it with a vacuum sealing machine, and then press it with isostatic pressing in an isostatic press to obtain a low-density target blank with a relative density of 65%; the isostatic pressing pressure is 250MPa, and the holding time is 20min.

[0092] S8. The low-density target blank is sintered at a temperature of 1600℃ for 3 hours. After calcination, it is naturally cooled to room temperature to obtain tantalum oxide-doped tin oxide target for RPD thin film.

[0093] The density of the tantalum oxide-doped tin oxide target obtained in Example 2 is 5.0729 g / cm³. 3 Its relative density is 72.47%.

[0094] The present invention discloses a method for preparing tantalum oxide-doped tin oxide targets for RPD thin films. By controlling the calcination and sintering temperatures, a tantalum oxide-doped tin oxide target with controllable density is obtained, ensuring a uniform target structure and improving the quality of the RPD thin film. The relative density of the target can be precisely controlled between 60% and 73% according to actual needs. When used as a target for preparing TCO coatings using the RPD method, the tantalum oxide-doped tin oxide target can improve the uniformity of the TCO coating and enhance its quality and performance, showing promising application prospects.

[0095] The technical solutions and technical details disclosed in the embodiments of this invention are merely illustrative of the inventive concept of this invention and do not constitute a limitation on the technical solutions of the embodiments of this invention. Any conventional changes, substitutions, or combinations made to the technical details disclosed in the embodiments of this invention have the same inventive concept as this invention and are within the protection scope of the claims of this invention.

Claims

1. A method for preparing a tantalum oxide-doped tin oxide target for RPD thin films, characterized in that, Including the following steps: S1, tin oxide, tantalum oxide, dispersant, and deionized water are ball-milled and mixed in a set ratio to obtain a primary slurry. The mass ratio of tin oxide to tantalum oxide is 90–99:1–10, the mass content of deionized water in the primary slurry is 50–70%, and the mass content of dispersant is 0.25–1.5%. The primary ball milling is carried out in a ball mill at a speed of 280–350 r / min, a ball-to-material ratio of 3:1, and a milling time of 4–18 hours. Ball milling is stopped when the D50 of the slurry is 0.3–0.7 μm. S2. Dry the mixed slurry and then pulverize it into powder, selecting powder with a particle size of less than 80-200 mesh; S3. The powder obtained in step S2 is calcined and the calcined powder is collected; wherein, the calcination temperature is 950-1500℃ and the calcination time is 2-8h. S4. The calcined powder, binder, dispersant, and deionized water are ball-milled and mixed in a set ratio to obtain a secondary slurry. The secondary slurry contains 0.5–2% dispersant, 50–70% deionized water, and 0.5–2% binder by mass. The secondary ball milling is carried out in a ball mill, including: the calcined powder, dispersant, and deionized water are ball-milled and mixed in a set ratio. The ball mill speed is set to 280–360 r / min, the ball-to-powder ratio is 3:1, and the milling time is 12–25 hours. Then, the binder is added, and ball milling continues for 1.5–4 hours. S5. Spray granulation is performed on the secondary slurry to obtain spherical granular powder; wherein, the spray granulation temperature is 195~225℃, the feed rate is 5~15ml / min, and the centrifuge frequency is 30~50Hz. S6. Spherical granular powder is molded to obtain a target blank; wherein the molding pressure is 30-50 MPa and the holding time is 3-10 min. S7. The target blank is subjected to isostatic pressing to obtain a low-density target blank with a relative density of 50-65%; wherein the isostatic pressing pressure is 100-300MPa and the holding time is 3-30min. S8. The low-density target blank is sintered to obtain tantalum oxide-doped tin oxide target for RPD thin film; wherein the sintering temperature is 1100~1600℃ and the sintering time is 3~12 hours.

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