Tin oxide doped target, method for improving oxygen vacancies on surface of tin oxide doped target

Abstract

The application belongs to the technical field of semiconductors, and discloses a method for improving surface oxygen vacancies of a tin oxide doped target material, which comprises the following steps: placing a tin oxide doped target material precursor and elemental titanium in the same environment under the conditions of vacuum and a sintering temperature of 1300-1600 DEG C, and keeping warm for a period of time to obtain the tin oxide doped target material. The method can significantly improve the surface oxygen vacancies of the tin oxide doped target material by selecting a metal which can rapidly combine with oxygen at the sintering temperature to non-contact co-sinter with the precursor. Meanwhile, the application also provides the tin oxide doped target material.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a tin oxide doped target and a method for increasing oxygen vacancies on the surface of the tin oxide doped target. Background Technology

[0002] Sputtering targets are fundamental consumables in the magnetron sputtering process, used in large quantities, and their quality plays a crucial role in determining the performance of thin films. Targets have a wide range of applications, including optical targets, display thin film targets, semiconductor targets, recording media targets, and superconducting targets. Among these, semiconductor, display, and recording media targets are the three most widely used. To improve the thin film preparation rate and ensure the growth quality of the thin film, sputtering targets must meet certain performance requirements. In recent years, flat panel display technologies such as liquid crystal displays, active organic light-emitting diode displays, and flexible displays have developed rapidly, making the importance of thin film transistors (TFTs) as core components self-evident. Among these, oxide semiconductor-based TFTs have attracted widespread attention due to their advantages such as high mobility, good electrical uniformity, high visible light transmittance, low preparation temperature, and low cost.

[0003] Tin dioxide is a wide-bandgap metal oxide semiconductor material. Tin dioxide ceramic materials have always been a research hotspot, with broad application prospects in gas sensors, liquid crystal displays, photodetectors, solar cells, photocatalysis, electrocatalysis, and protective coatings. Theoretically, pure tin dioxide films have very poor conductivity. Generally, during the preparation of tin dioxide targets, doping or controlling the sintering atmosphere to generate oxygen vacancies in tin dioxide greatly improves its conductivity, making it more suitable for sputtering applications.

[0004] In addition, there are other methods to increase oxygen vacancies:

[0005] Acid etching method: CN113526567A discloses a method for preparing oxygen vacancy type metal oxides by controlling the acid etching effect. The specific technical solution is as follows: prepare an inorganic acid or organic acid solution of a certain concentration, add a certain amount of the original metal oxide to the acid solution, and perform acid etching reaction at 25-50℃ for 1-80 hours. After centrifugation, solid-liquid separation is achieved. After subsequent washing with deionized water and anhydrous ethanol and drying, oxygen vacancy type metal oxides can be obtained.

[0006] Microwave Method: CN106564892A discloses a method for intrinsically modifying transition metal oxides to introduce oxygen vacancies, comprising the following steps: thoroughly mixing transition metal oxides and graphene oxide solutions according to elemental ratios to obtain a dispersion; rapidly freeze-drying the dispersion to obtain an intermediate sample; freeze-drying the intermediate sample again to obtain a metal oxide-graphene oxide composite; and microwave combustion treating the metal oxide-graphene oxide composite to obtain a modified material. This invention uses transition metal oxides and graphene oxide as raw materials, uniformly coating, freezing, drying, and microwave combustion treating the raw materials. By controlling the concentration, freeze-drying time, and microwave combustion treatment time, metal oxides or carbides with different degrees of reduction are obtained. This rapidly prepares modified materials with extremely high electrochemical performance, greatly overcoming the problem of poor conductivity in transition metal oxides.

[0007] For shaped target precursors, the acid etching and microwave methods mentioned above are more suitable for powders, but not so suitable for large-volume targets.

[0008] Therefore, the technical problem to be solved in this case is: how to increase the surface oxygen vacancies of tin oxide target material. Summary of the Invention

[0009] One of the objectives of this invention is to provide a method for increasing the oxygen vacancies on the surface of a tin oxide-doped target. This method significantly increases the oxygen vacancies on the surface of the tin oxide-doped target by using a metal that can rapidly combine with oxygen at the sintering temperature and co-firing it with the precursor in a non-contact manner.

[0010] In addition, the present invention also provides the tin oxide doped target.

[0011] Unless otherwise specified in this invention, M stands for mol / L and % stands for mass percentage.

[0012] To achieve the above objectives, the present invention provides a method for increasing the oxygen vacancies on the surface of a tin oxide-doped target. Under vacuum conditions and a sintering temperature of 1300-1600℃, a tin oxide-doped target precursor and elemental titanium are placed in the same environment and kept at that temperature for a period of time to obtain a tin oxide-doped target.

[0013] It should be noted that the amount of elemental titanium can be more or less. Generally speaking, it is acceptable to use more than 0.1 wt% of tin oxide doped target material, preferably more than 1 wt%, more preferably more than 10 wt%, more preferably more than 30 wt%, more preferably more than 50 wt%, and more preferably more than 80 wt%.

[0014] Titanium was chosen because, compared to other reactive metals such as magnesium, it has a high melting point and exhibits strong oxygen binding capacity at the precursor sintering temperature. Furthermore, unlike other metals with low vaporization points, it does not vaporize or sublimate, thus avoiding contamination of the target material. Therefore, after screening, titanium is a superior material suitable for this invention.

[0015] In the above-described method for increasing oxygen vacancies on the surface of a tin oxide-doped target, the metal oxide in the tin oxide-doped target precursor is tin oxide and a doped metal oxide; the amount of the doped metal oxide is 1%-3% of the total molar amount of the metal oxide.

[0016] Preferably, the amount of doped metal oxide is 2%-3% of the total molar amount of the metal oxide;

[0017] In some implementations, the amount of doped metal oxide used is 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, and 2.9% of the total molar amount of metal oxide;

[0018] In the above-described method for increasing oxygen vacancies on the surface of a tin oxide-doped target, the doped metal oxide is molybdenum oxide or tungsten oxide.

[0019] This invention does not exclude other metal oxides. Generally speaking, doped oxides suitable for tin oxide targets should also be suitable for this invention.

[0020] In the above-mentioned method for increasing oxygen vacancies on the surface of tin oxide-doped target, the method specifically includes:

[0021] Inside the sintering equipment, a quartz boat and a tin oxide-doped target precursor are placed, and the quartz boat contains powdered elemental titanium.

[0022] The sintering equipment is evacuated and heated at a rate of 0.1-0.5 / min. After reaching the set temperature, it is held for 8-12 hours.

[0023] Preferably, tin oxide powder is spread inside the sintering equipment to improve thermal conductivity and prevent the tin oxide-doped target precursor from adhering to the sintering equipment.

[0024] In the above-described method for increasing the oxygen vacancies on the surface of a tin oxide-doped target, the tin oxide-doped target precursor is prepared by the following method:

[0025] Step 1: Mix tin oxide, doped metal oxide, dispersant, binder, and water, and grind to obtain a slurry;

[0026] Step 2: Spray-dry the slurry to obtain powder;

[0027] Step 3: Shape the powder;

[0028] Step 4: Degrease and heat the product obtained in Step 3 to obtain tin oxide doped target precursor.

[0029] In the above method for increasing oxygen vacancies on the surface of a tin oxide-doped target, step 1 is as follows:

[0030] The doped metal oxide and the first dispersant were poured into a slurry tank containing pure water, dispersed evenly, and then wet-milled to obtain slurry one.

[0031] Add the weighed tin oxide powder, pure water, and second dispersant to slurry one, disperse evenly, and then wet grind to obtain slurry two.

[0032] Add a binder to slurry two, disperse it evenly, and then wet grind it to obtain slurry three.

[0033] In the above-described method for increasing oxygen vacancies on the surface of tin oxide-doped target, the first dispersant accounts for 1-5% of the total mass of slurry one; the first dispersant is one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, or sodium hexadecylbenzenesulfonate.

[0034] The second dispersant accounts for 1-15% of the total mass of the added tin oxide powder and the second dispersant; the first dispersant is one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate or sodium hexadecylbenzenesulfonate.

[0035] The binder accounts for 5-15% of the total mass of the metal oxide and the binder; the binder is a mixture of polyvinyl alcohol and polyethylene glycol, polyvinyl alcohol or polyvinyl butyral, or one or both.

[0036] In the above-mentioned method for increasing the oxygen vacancies on the surface of tin oxide doped target, the grinding speed of wet grinding involved in slurry one and slurry two is 1200-1800 r / min; the wet grinding time involved in slurry one is 8-15 h; and the wet grinding time involved in slurry two is 2-4 h.

[0037] In the above method for increasing oxygen vacancies on the surface of tin oxide doped target, the forming operation in step 3 is: sequential molding and cold isostatic pressing.

[0038] The degreasing temperature in step 4 is 400℃-600℃, and the holding time is 6-12 hours.

[0039] Meanwhile, the present invention also discloses a tin oxide doped target material, which is prepared by any of the methods described above.

[0040] Beneficial effects

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] (1) In this invention, elemental titanium was selected as a material for adsorbing oxygen. It has the advantages of being difficult to vaporize, having a high melting point, and being able to rapidly combine with oxygen at the sintering temperature. These are characteristics that many other elemental metals do not have.

[0043] (2) The present invention optimizes oxygen vacancies while sintering, which can not only increase the oxygen vacancies on the surface, but also increase the oxygen vacancies in the inner layer.

[0044] Through the above optimizations, its conductivity can be greatly improved, making it better suited for use in the sputtering field. Detailed Implementation

[0045] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0046] To illustrate the technical content of the present invention in detail, the following description is provided in conjunction with the embodiments.

[0047] Example 1

[0048] Step 1: Weigh out tin oxide and molybdenum oxide powders according to a molar ratio of 97:3 (mass ratio: 97.13:2.87) and set aside.

[0049] Step 2: Add a certain amount of pure water to the slurry tank, and add the molybdenum oxide powder and PVP weighed in step (1) to the slurry tank for pre-dispersion. The dispersion time is 30 min and the dispersion speed is 100 rpm. PVP accounts for 4% of the total mass of the added molybdenum oxide powder, pure water and PVP.

[0050] Step 3: The slurry obtained in Step 2 is pumped into a sand mill using a pneumatic diaphragm pump for grinding. The grinding time is 12 hours and the grinding speed is 1500 r / min, to obtain slurry one.

[0051] Step 4: Add tin oxide powder and PVP to the slurry obtained in Step 3 and disperse for 30 minutes at a speed of 100 rpm. Then, use a pneumatic diaphragm pump to feed the resulting slurry into a sand mill for grinding for 8 hours at a speed of 1500 rpm to obtain slurry two. PVP accounts for 4% of the total mass of the added tin oxide powder and PVP.

[0052] Step 5: PVA is added to slurry two obtained in step 4, and pre-dispersion is performed for 30 minutes at a dispersion speed of 100 rpm. Then, the slurry is pumped into a sand mill using a pneumatic diaphragm pump for grinding for 2 hours at a grinding speed of 1500 rpm to obtain slurry three. The binder accounts for 10% of the total mass of the added tin oxide powder, molybdenum oxide, and binder.

[0053] Step 6: The slurry obtained in Step 5 is fed into a spray drying tower for spray granulation, followed by mixing and sieving to obtain tin oxide-doped molybdenum oxide mixed powder. The outlet air temperature is 75℃, and the atomizer frequency is 120Hz.

[0054] Step 7: The mixed powder obtained in Step 6 is molded and cold isostatically pressed to obtain tin oxide-doped molybdenum oxide target blanks;

[0055] The molding process is as follows: after filling the 200mm mold with mixed powder, it is placed in a hydraulic press and hydraulically pressed at a pressure of 50Mpa. After demolding, tin oxide-doped molybdenum oxide target blanks are obtained.

[0056] The process parameters for cold isostatic pressing are as follows: the obtained tin oxide-doped molybdenum oxide target blank is placed in a soft-pack film, which is generally made of PE plastic bag. The sealed bag is then placed in a cold isostatic press and immersed in a liquid pressure medium. The blank is then pressed by high-pressure liquid injected by a high-pressure pump at a pressure of 380 MPa to obtain the tin oxide-doped molybdenum oxide target blank.

[0057] Step 8: Place the target blank obtained in step 7 into a sintering furnace for degreasing heat treatment. Under an air atmosphere, the temperature is controlled at 500℃ with a heating rate of 0.5 / min and a holding time of 8 hours. Then cool to room temperature to remove additives and other organic matter from the target blank.

[0058] Step 9: Spread a layer of tin oxide fine sand with a thickness of about 1.5-2.5mm evenly on the sintering plate of the sintering furnace. The purity of the tin oxide fine sand is not less than 98%, and the particle size is between 0.15-0.25mm.

[0059] Step 10: Place the heat-treated target blank from Step 8 on the spread tin oxide sand, cover it with a firing plate, and place a quartz boat filled with titanium powder on the firing plate. The titanium powder has a purity of 99.99% and its weight is 80% of the target blank's weight.

[0060] Step 11: Close the furnace door and perform vacuum sintering at a heating rate of 1℃ / min. After heating to 1400℃, hold for 10 hours to obtain the target material.

[0061] Step 12: The relative density of the target material obtained in Step 11 was measured to be 98.68%, and the oxygen vacancy concentration was 7.12E+19cm-3.

[0062] Step 13: The obtained target material was sputtered using a sputtering coating machine with Ar / O2 / H2 as the working gas. The sputtering power was 100W, the pressure was 0.4Pa, the substrate temperature was 200℃, the gas flow rate was 1%O2 / 1.8%H2, the pre-sputtering time was 300s, and the sputtering time was 380s. The measured glass slide mobility was 12.7cm. 2 / (V·S).

[0063] Example 2

[0064] Step 1: Weigh out tin oxide and tungsten oxide powders according to a molar ratio of 97:3 (mass ratio of 95.46:4.54) and set aside.

[0065] Step 2: Add a certain amount of pure water to the slurry tank, and add the tungsten oxide powder and PVP weighed in step (1) to the slurry tank for pre-dispersion. The dispersion time is 30 min and the dispersion speed is 100 rpm. PVP accounts for 4% of the total mass of the added tungsten oxide powder, pure water and PVP.

[0066] Step 3: The slurry obtained in Step 2 is pumped into a sand mill using a pneumatic diaphragm pump for grinding. The grinding time is 12 hours and the grinding speed is 1500 r / min, to obtain slurry one.

[0067] Step 4: Add tin oxide powder and PVP to the slurry obtained in Step 3 and disperse for 30 minutes at a speed of 100 rpm. Then, use a pneumatic diaphragm pump to feed the resulting slurry into a sand mill for grinding for 8 hours at a speed of 1500 rpm to obtain slurry two. PVP accounts for 4% of the total mass of the added tin oxide powder and PVP.

[0068] Step 5: PVA is added to slurry two obtained in step 4, and then pre-dispersed for 30 minutes at a dispersion speed of 100 rpm. The slurry is then pumped into a sand mill using a pneumatic diaphragm pump for grinding for 2 hours at a grinding speed of 1500 rpm, yielding slurry three. The binder constitutes 10% of the total mass of the added tin oxide powder, tungsten oxide, and binder.

[0069] Step 6: The slurry obtained in Step 5 is fed into a spray drying tower for spray granulation, followed by mixing and sieving to obtain tin oxide-doped tungsten oxide mixed powder. The outlet air temperature is 75℃, and the atomizer frequency is 120Hz.

[0070] Step 7: The mixed powder obtained in Step 6 is molded and cold isostatically pressed (process is the same as in Example 1) to obtain tin oxide-doped tungsten oxide target blanks.

[0071] Step 8: Place the target blank obtained in step 7 into a sintering furnace for degreasing heat treatment. Under an air atmosphere, the temperature is controlled at 500℃ with a heating rate of 0.5 / min and a holding time of 8 hours. Then cool to room temperature to remove additives and other organic matter from the target blank.

[0072] Step 9: Spread a layer of tin oxide fine sand with a thickness of about 1.5-2.5mm evenly on the sintering plate of the sintering furnace. The purity of the tin oxide fine sand is not less than 98%, and the particle size is between 0.15-0.25mm.

[0073] Step 10: Place the heat-treated target blank from Step 8 on the spread tin oxide sand, cover it with a firing plate, and place a quartz boat filled with titanium powder on the firing plate. The titanium powder has a purity of 99.99% and its weight is 80% of the target blank's weight.

[0074] Step 11: Close the furnace door and perform vacuum sintering at a heating rate of 1℃ / min. After heating to 1400℃, hold for 10 hours to obtain the target material.

[0075] Step 12: The relative density of the target material obtained in Step 11 was measured to be 98.56%, and the oxygen vacancy concentration was 6.47E+19cm-3.

[0076] Step 13: The obtained target material was sputtered using a sputtering coating machine with Ar / O2 / H2 as the working gas. The sputtering power was 100W, the pressure was 0.4Pa, the substrate temperature was 200℃, the gas flow rate was 1% O2 / 1.8% H2, the pre-sputtering time was 300s, and the sputtering time was 380s. The measured glass slide mobility was 12.2cm. 2 / (V·S).

[0077] Example 3

[0078] Step 1: Weigh out tin oxide and molybdenum oxide powders according to a molar ratio of 98:2 (mass ratio: 98.09:1.91) and set aside.

[0079] Step 2: Add a certain amount of pure water to the slurry tank, and add the molybdenum oxide powder and PVP weighed in step (1) to the slurry tank for pre-dispersion. The dispersion time is 30 min and the dispersion speed is 100 rpm. PVP accounts for 4% of the total mass of the added molybdenum oxide powder, pure water and PVP.

[0080] Step 3: The slurry obtained in Step 2 is pumped into a sand mill using a pneumatic diaphragm pump for grinding. The grinding time is 12 hours and the grinding speed is 1500 r / min, to obtain slurry one.

[0081] Step 4: Add tin oxide powder and PVP to the slurry obtained in Step 3 and disperse for 30 minutes at a speed of 100 rpm. Then, use a pneumatic diaphragm pump to feed the resulting slurry into a sand mill for grinding for 8 hours at a speed of 1500 rpm to obtain slurry two. PVP accounts for 4% of the total mass of the added tin oxide powder and PVP.

[0082] Step 5: PVA is added to slurry two obtained in step 4, and pre-dispersion is performed for 30 minutes at a dispersion speed of 100 rpm. Then, the slurry is pumped into a sand mill using a pneumatic diaphragm pump for grinding for 2 hours at a grinding speed of 1500 rpm to obtain slurry three. The binder accounts for 10% of the total mass of the added tin oxide powder, molybdenum oxide, and binder.

[0083] Step 6: The slurry obtained in Step 5 is fed into a spray drying tower for spray granulation, followed by mixing and sieving to obtain tin oxide-doped molybdenum oxide mixed powder. The outlet air temperature is 75℃, and the atomizer frequency is 120Hz.

[0084] Step 7: The mixed powder obtained in Step 6 is molded and cold isostatically pressed (process same as in Example 1) to obtain tin oxide-doped molybdenum oxide target blanks.

[0085] Step 8: Place the target blank obtained in step 7 into a sintering furnace for degreasing heat treatment. Under an air atmosphere, the temperature is controlled at 500℃ with a heating rate of 0.5 / min and a holding time of 8 hours. Then cool to room temperature to remove additives and other organic matter from the target blank.

[0086] Step 9: Spread a layer of tin oxide fine sand with a thickness of about 1.5-2.5mm evenly on the sintering plate of the sintering furnace. The purity of the tin oxide fine sand is not less than 98%, and the particle size is between 0.15-0.25mm.

[0087] Step 10: Place the heat-treated target blank from Step 8 on the spread tin oxide sand, cover it with a firing plate, and place a quartz boat filled with titanium powder on the firing plate. The titanium powder has a purity of 99.99% and its weight is 80% of the target blank's weight.

[0088] Step 11: Close the furnace door and perform vacuum sintering at a heating rate of 1℃ / min. After heating to 1400℃, hold for 10 hours to obtain the target material.

[0089] Step 12: The relative density of the target material obtained in Step 11 was measured to be 99.23%, and the oxygen vacancy concentration was 8.62E+19cm-3.

[0090] Step 13: The obtained target material was sputtered using a sputtering coating machine with Ar / O2 / H2 as the working gas. The sputtering power was 100W, the pressure was 0.4Pa, the substrate temperature was 200℃, the gas flow rate was 1%O2 / 1.8%H2, the pre-sputtering time was 300s, and the sputtering time was 380s. The measured glass slide mobility was 14.5cm. 2 / (V·S).

[0091] Example 4

[0092] Step 1: Weigh out tin oxide and tungsten oxide powders according to a molar ratio of 98:2 (mass ratio: 96.96:3.04) and set aside.

[0093] Step 2: Add a certain amount of pure water to the slurry tank, and add the tungsten oxide powder and PVP weighed in step (1) to the slurry tank for pre-dispersion. The dispersion time is 30 min and the dispersion speed is 100 rpm. PVP accounts for 4% of the total mass of the added tungsten oxide powder, pure water and PVP.

[0094] Step 3: The slurry obtained in Step 2 is pumped into a sand mill using a pneumatic diaphragm pump for grinding. The grinding time is 12 hours and the grinding speed is 1500 r / min, to obtain slurry one.

[0095] Step 4: Add tin oxide powder and PVP to the slurry obtained in Step 3 and disperse for 30 minutes at a speed of 100 rpm. Then, use a pneumatic diaphragm pump to feed the resulting slurry into a sand mill for grinding for 8 hours at a speed of 1500 rpm to obtain slurry two. PVP accounts for 4% of the total mass of the added tin oxide powder and PVP.

[0096] Step 5: PVA is added to slurry two obtained in step 4, and then pre-dispersed for 30 minutes at a dispersion speed of 100 rpm. The slurry is then pumped into a sand mill using a pneumatic diaphragm pump for grinding for 2 hours at a grinding speed of 1500 rpm, yielding slurry three. The binder constitutes 10% of the total mass of the added tin oxide powder, tungsten oxide, and binder.

[0097] Step 6: The slurry obtained in Step 5 is fed into a spray drying tower for spray granulation, followed by mixing and sieving to obtain tin oxide-doped tungsten oxide mixed powder. The outlet air temperature is 75℃, and the atomizer frequency is 120Hz.

[0098] Step 7: The mixed powder obtained in Step 6 is molded and cold isostatically pressed (process same as in Example 1) to obtain tin oxide-doped tungsten oxide target blanks.

[0099] Step 8: Place the target blank obtained in step 7 into a sintering furnace for degreasing heat treatment. Under an air atmosphere, the temperature is controlled at 500℃ with a heating rate of 0.5 / min and a holding time of 8 hours. Then cool to room temperature to remove additives and other organic matter from the target blank.

[0100] Step 9: Spread a layer of tin oxide fine sand with a thickness of about 1.5-2.5mm evenly on the sintering plate of the sintering furnace. The purity of the tin oxide fine sand is not less than 98%, and the particle size is between 0.15-0.25mm.

[0101] Step 10: Place the heat-treated target blank from Step 8 on the spread tin oxide fine sand, cover it with a firing plate, and place a quartz boat filled with titanium powder on the firing plate. The titanium powder has a purity of 99.99% and its weight is 80% of the target blank's weight. The elemental titanium absorbs oxygen from tin oxide-doped tungsten oxide or the tungsten oxide lattice under vacuum conditions, causing surface defects to be generated, thereby increasing its carrier concentration and conductivity.

[0102] Step 11: Close the furnace door and perform vacuum sintering at a heating rate of 1℃ / min. After heating to 1400℃, hold for 10 hours to obtain the target material.

[0103] Step 12: The relative density of the target material obtained in Step 11 was measured to be 98.79%, and the oxygen vacancy concentration was 7.95E+19cm-3.

[0104] Step 13: The obtained target material was sputtered using a sputtering coating machine with Ar / O2 / H2 as the working gas. The sputtering power was 100W, the pressure was 0.4Pa, the substrate temperature was 200℃, the gas flow rate was 1% O2 / 1.8% H2, the pre-sputtering time was 300s, and the sputtering time was 380s. The measured glass slide mobility was 13.4cm. 2 / (V·S).

[0105] Example 5

[0106] Step 1: Weigh out tin oxide and molybdenum oxide powders according to the molar ratio of 97.5:2.5 (mass ratio: 97.61:2.39) and set aside.

[0107] Step 2: Add a certain amount of pure water to the slurry tank, and add the molybdenum oxide powder and PVP weighed in step (1) to the slurry tank for pre-dispersion. The dispersion time is 30 min and the dispersion speed is 100 rpm. PVP accounts for 4% of the total mass of the added molybdenum oxide powder, pure water and PVP.

[0108] Step 3: The slurry obtained in Step 2 is pumped into a sand mill using a pneumatic diaphragm pump for grinding. The grinding time is 12 hours and the grinding speed is 1500 r / min, to obtain slurry one.

[0109] Step 4: Add tin oxide powder and PVP to the slurry obtained in Step 3 and disperse for 30 minutes at a speed of 100 rpm. Then, use a pneumatic diaphragm pump to feed the resulting slurry into a sand mill for grinding for 8 hours at a speed of 1500 rpm to obtain slurry two. PVP accounts for 4% of the total mass of the added tin oxide powder and PVP.

[0110] Step 5: PVA is added to slurry two obtained in step 4, and pre-dispersion is performed for 30 minutes at a dispersion speed of 100 rpm. Then, the slurry is pumped into a sand mill using a pneumatic diaphragm pump for grinding for 2 hours at a grinding speed of 1500 rpm to obtain slurry three. The binder accounts for 10% of the total mass of the added tin oxide powder, molybdenum oxide, and binder.

[0111] Step 6: The slurry obtained in Step 5 is fed into a spray drying tower for spray granulation, followed by mixing and sieving to obtain tin oxide-doped molybdenum oxide mixed powder. The outlet air temperature is 75℃, and the atomizer frequency is 120Hz.

[0112] Step 7: The mixed powder obtained in Step 6 is molded and cold isostatically pressed (process is the same as in Example 1) to obtain tin oxide-doped molybdenum oxide target blank;

[0113] Step 8: Place the target blank obtained in step 7 into a sintering furnace for degreasing heat treatment. Under an air atmosphere, the temperature is controlled at 500℃ with a heating rate of 0.5 / min and a holding time of 8 hours. Then cool to room temperature to remove additives and other organic matter from the target blank.

[0114] Step 9: Spread a layer of tin oxide fine sand with a thickness of about 1.5-2.5mm evenly on the sintering plate of the sintering furnace. The purity of the tin oxide fine sand is not less than 98%, and the particle size is between 0.15-0.25mm.

[0115] Step 10: Place the heat-treated target blank from Step 8 on the prepared tin oxide fine sand, cover it with a firing plate, and place a quartz boat filled with titanium powder on the firing plate. The titanium powder has a purity of 99.99% and its weight is 80% of the target blank's weight. The elemental titanium absorbs oxygen from tin oxide-doped molybdenum oxide or the molybdenum oxide lattice under vacuum conditions, causing surface defects to be generated, thereby increasing its carrier concentration and conductivity.

[0116] Step 11: Close the furnace door and perform vacuum sintering at a heating rate of 1℃ / min. After heating to 1400℃, hold for 10 hours to obtain the target material.

[0117] Step 12: The relative density of the target material obtained in Step 11 was measured to be 98.85%, and the oxygen vacancy concentration was 6.39E+19cm-3.

[0118] Step 13: The obtained target material was sputtered using a sputtering coating machine with Ar / O2 / H2 as the working gas. The sputtering power was 100W, the pressure was 0.4Pa, the substrate temperature was 200℃, the gas flow rate was 1%O2 / 1.8%H2, the pre-sputtering time was 300s, and the sputtering time was 380s. The measured glass slide mobility was 12.6cm. 2 / (V·S).

[0119] Comparative Example 1

[0120] Step 1: Weigh out tin oxide and molybdenum oxide powders according to a molar ratio of 98:2 and set aside.

[0121] Step 2: Add a certain amount of pure water to the slurry tank, and add the molybdenum oxide powder and PVP weighed in step (1) to the slurry tank for pre-dispersion. The dispersion time is 30 min and the dispersion speed is 100 rpm. PVP accounts for 4% of the total mass of the added molybdenum oxide powder, pure water and PVP.

[0122] Step 3: The slurry obtained in Step 2 is pumped into a sand mill using a pneumatic diaphragm pump for grinding. The grinding time is 12 hours and the grinding speed is 1500 r / min, to obtain slurry one.

[0123] Step 4: Add tin oxide powder and PVP to the slurry obtained in Step 3 and disperse for 30 minutes at a speed of 100 rpm. Then, use a pneumatic diaphragm pump to feed the resulting slurry into a sand mill for grinding for 8 hours at a speed of 1500 rpm to obtain slurry two. PVP accounts for 4% of the total mass of the added tin oxide powder and PVP.

[0124] Step 5: PVA is added to slurry two obtained in step 4, and pre-dispersion is performed for 30 minutes at a dispersion speed of 100 rpm. Then, the slurry is pumped into a sand mill using a pneumatic diaphragm pump for grinding for 2 hours at a grinding speed of 1500 rpm to obtain slurry three. The binder accounts for 10% of the total mass of the added tin oxide powder, molybdenum oxide, and binder.

[0125] Step 6: The slurry obtained in Step 5 is fed into a spray drying tower for spray granulation, followed by mixing and sieving to obtain tin oxide-doped molybdenum oxide mixed powder. The outlet air temperature is 75℃, and the atomizer frequency is 120Hz.

[0126] Step 7: The mixed powder obtained in Step 6 is molded and cold isostatically pressed (process same as in Example 1) to obtain tin oxide-doped molybdenum oxide target blanks.

[0127] Step 8: Place the target blank obtained in step 7 into a sintering furnace for degreasing heat treatment. Under an air atmosphere, the temperature is controlled at 500℃ with a heating rate of 0.5 / min and a holding time of 8 hours. Then cool to room temperature to remove additives and other organic matter from the target blank.

[0128] Step 9: Place the target blank obtained in step 8 into a sintering furnace for sintering. The heating rate is 1℃ / min. After heating to 1400℃, hold for 10h to obtain the target material.

[0129] Step 10: Test the density of the target material obtained in Step 9, obtaining a relative density of 95.37% and an oxygen vacancy concentration of 5.28E+15cm. -3 .

[0130] Step 11: The obtained target material was sputtered using a sputtering coating machine with Ar / O2 / H2 as the working gas. The sputtering power was 100W, the pressure was 0.4Pa, the substrate temperature was 200℃, the gas flow rate was 1%O2 / 1.8%H2, the pre-sputtering time was 300s, and the sputtering time was 380s. The measured glass slide mobility was 9.58cm. 2 / (V·S).

[0131] By comparing Comparative Example 1 and Example 3, it can be found that without using elemental titanium, the relative density decreased by about 4%, and the oxygen vacancy density decreased by 4 orders of magnitude.

[0132] The reason for the decrease in relative density is that when sintering the target material without using elemental titanium, some oxygen will be released under high temperature. The presence of this oxygen in the sintering furnace may cause the heating elements in the sintering furnace to be oxidized and cause heat loss, resulting in a lower actual sintering temperature than when using elemental titanium.

[0133] This also shows that titanium can not only improve surface oxygen vacancies, but also has a significant impact on the internal oxygen vacancies and the arrangement of oxides.

[0134] Comparative Example 2

[0135] Step 1: Weigh out tin oxide and molybdenum oxide in a molar ratio of 95:5 and set aside.

[0136] Step 2: Add a certain amount of pure water to the slurry tank, and add the molybdenum oxide powder and PVP weighed in step (1) to the slurry tank for pre-dispersion. The dispersion time is 30 min and the dispersion speed is 100 rpm. PVP accounts for 4% of the total mass of the added molybdenum oxide powder, pure water and PVP.

[0137] Step 3: The slurry obtained in Step 2 is pumped into a sand mill using a pneumatic diaphragm pump for grinding. The grinding time is 12 hours and the grinding speed is 1500 r / min, to obtain slurry one.

[0138] Step 4: Add tin oxide powder and PVP to the slurry obtained in Step 3 and disperse for 30 minutes at a speed of 100 rpm. Then, use a pneumatic diaphragm pump to feed the resulting slurry into a sand mill for grinding for 8 hours at a speed of 1500 rpm to obtain slurry two. PVP accounts for 4% of the total mass of the added tin oxide powder and PVP.

[0139] Step 5: PVA is added to slurry two obtained in step 4, and pre-dispersion is performed for 30 minutes at a dispersion speed of 100 rpm. Then, the slurry is pumped into a sand mill using a pneumatic diaphragm pump for grinding for 2 hours at a grinding speed of 1500 rpm to obtain slurry three. The binder accounts for 10% of the total mass of the added tin oxide powder, molybdenum oxide, and binder.

[0140] Step 6: The slurry obtained in Step 5 is fed into a spray drying tower for spray granulation, followed by mixing and sieving to obtain tin oxide-doped molybdenum oxide mixed powder. The outlet air temperature is 75℃, and the atomizer frequency is 120Hz.

[0141] Step 7: The mixed powder obtained in Step 6 is molded and cold isostatically pressed (process same as in Example 1) to obtain tin oxide-doped molybdenum oxide target blanks.

[0142] Step 8: Place the target blank obtained in step 7 into a sintering furnace for degreasing heat treatment. Under an air atmosphere, the temperature is controlled at 500℃ with a heating rate of 0.5 / min and a holding time of 8 hours. Then cool to room temperature to remove additives and other organic matter from the target blank.

[0143] Step 9: Spread a layer of tin oxide fine sand with a thickness of about 1.5-2.5mm evenly on the sintering plate of the sintering furnace. The purity of the tin oxide fine sand is not less than 98%, and the particle size is between 0.15-0.25mm.

[0144] Step 10: Place the heat-treated target blank from Step 8 on the spread tin oxide sand, cover it with a firing plate, and place a quartz boat filled with titanium powder on the firing plate. The titanium powder has a purity of 99.99% and its weight is 80% of the target blank's weight.

[0145] Step 11: Close the furnace door and perform vacuum sintering at a heating rate of 1℃ / min. After heating to 1400℃, hold for 10 hours to obtain the target material.

[0146] Step 12: Test the density of the target material obtained in Step 11. The relative density is 96.29% and the oxygen vacancy concentration is 8.54E+16cm-3.

[0147] Step 13: The obtained target material was sputtered using a sputtering coating machine with Ar / O2 / H2 as the working gas. The sputtering power was 100W, the pressure was 0.4Pa, the substrate temperature was 200℃, the gas flow rate was 1%O2 / 1.8%H2, the pre-sputtering time was 300s, and the sputtering time was 380s. The measured glass slide mobility was 7.76cm. 2 / (V·S).

[0148] By comparing Comparative Example 2 and Example 1, it can be found that when elemental titanium is used, the relative density decreases by about 2.4%, and the oxygen vacancy density decreases by 3 orders of magnitude.

[0149] Combining Examples 1, 3, and Comparative Example 2, it can be observed that titanium is not the only factor capable of improving surface oxygen vacancies. The amount of doped oxide also affects the concentration of oxygen vacancies. Excessive doping is detrimental to increasing the concentration of oxygen vacancies, significantly impacting both the internal oxygen vacancies and the arrangement of oxides. However, it is noteworthy that even with excessive doping oxide, the results are still significantly better than without titanium.

[0150] Comparative Example 3

[0151] Step 1: Weigh out tin oxide and molybdenum oxide in a molar ratio of 95:5 and set aside.

[0152] Step 2: Add a certain amount of pure water to the slurry tank, and add the molybdenum oxide powder and PVP weighed in step (1) to the slurry tank for pre-dispersion. The dispersion time is 30 min and the dispersion speed is 100 rpm. PVP accounts for 4% of the total mass of the added molybdenum oxide powder, pure water and PVP.

[0153] Step 3: The slurry obtained in Step 2 is pumped into a sand mill using a pneumatic diaphragm pump for grinding. The grinding time is 12 hours and the grinding speed is 1500 r / min, to obtain slurry one.

[0154] Step 4: Add tin oxide powder and PVP to the slurry obtained in Step 3 and disperse for 30 minutes at a speed of 100 rpm. Then, use a pneumatic diaphragm pump to feed the resulting slurry into a sand mill for grinding for 8 hours at a speed of 1500 rpm to obtain slurry two. PVP accounts for 4% of the total mass of the added tin oxide powder and PVP.

[0155] Step 5: PVA is added to slurry two obtained in step 4, and pre-dispersion is performed for 30 minutes at a dispersion speed of 100 rpm. Then, the slurry is pumped into a sand mill using a pneumatic diaphragm pump for grinding for 2 hours at a grinding speed of 1500 rpm to obtain slurry three. The binder accounts for 10% of the total mass of the added tin oxide powder, molybdenum oxide, and binder.

[0156] Step 6: The slurry obtained in Step 5 is fed into a spray drying tower for spray granulation, followed by mixing and sieving to obtain tin oxide-doped molybdenum oxide mixed powder. The outlet air temperature is 75℃, and the atomizer frequency is 120Hz.

[0157] Step 7: The mixed powder obtained in Step 6 is molded and cold isostatically pressed (process same as in Example 1) to obtain tin oxide-doped molybdenum oxide target blanks.

[0158] Step 8: Place the target blank obtained in step 7 into a sintering furnace for degreasing heat treatment. Under an air atmosphere, the temperature is controlled at 500℃ with a heating rate of 0.5 / min and a holding time of 8 hours. Then cool to room temperature to remove additives and other organic matter from the target blank.

[0159] Step 9: Place the target blank obtained in Step 8 into a sintering furnace for sintering. The heating rate is 1℃ / min, and the temperature is raised to 1400℃ and held for 10 hours. The target material is then obtained.

[0160] Step 9: Test the density of the target material obtained in Step 9. The relative density is 96.84%, and the oxygen vacancy concentration is 3.68E+14cm. -3 .

[0161] Step 10: The obtained target material was sputtered using a sputtering coating machine with Ar / O2 / H2 as the working gas. The sputtering power was 100W, the pressure was 0.4Pa, the substrate temperature was 200℃, the gas flow rate was 1%O2 / 1.8%H2, the pre-sputtering time was 300s, and the sputtering time was 380s. The measured glass slide mobility was 6.12cm. 2 / (V·S).

[0162] A horizontal comparison between Comparative Example 3 and Comparative Example 1 reveals that the higher the doping concentration, the greater the density. This is somewhat inconsistent with the conclusion of Comparative Example 2. The possible reason for this is that neither Comparative Example 3 nor Comparative Example 1 involved titanium. Of course, the underlying reasons require further research and analysis.

[0163] Although Comparative Example 3 and Comparative Example 1 had different doping amounts, they maintained a strong consistency in oxygen vacancy concentration, differing by only one order of magnitude. This indicates that the participation of titanium plays a dominant role in the concentration of oxygen vacancy.

[0164] It should also be noted that when the doping concentration is below 0.5%, the target material is not industrially practical. Therefore, this study will not investigate the effect of titanium when the doping oxide concentration is too low.

[0165] In summary, the characteristics of this case are as follows:

[0166] 1. Titanium was selected through repeated optimization in this project. Titanium oxide has the following characteristics: high temperature stability and it is not easy to vaporize or sublimate; elemental titanium has the following characteristics: it is not easy to soften at sintering temperature, it has good activity at sintering temperature, and it is not easy to vaporize or sublimate. The former ensures that it does not contaminate the target material, and the latter ensures that it can effectively absorb oxygen.

[0167] For example, iron decomposes above 1200℃; aluminum has an oxide film on its surface, making it difficult to react; alkali metals are too reactive and easily volatilize; zinc sublimates at around 1000℃.

[0168] Therefore, titanium was the preferred material selected after repeated research in this case.

[0169] 2. This method employs a non-contact, simultaneous calcination and oxygen vacancy treatment, which alters not only the surface oxygen vacancy but also the internal oxygen vacancy, leading to a change in density. Therefore, compared to existing traditional methods, this method not only significantly optimizes oxygen vacancy concentration but is also more suitable for processing large-sized targets.

[0170] The embodiments presented herein are merely selected implementations based on combinations of all possible embodiments. The appended claims should not be limited to the embodiments described herein. Some numerical ranges used in the claims include sub-ranges within them, and variations within these ranges should also be covered by the appended claims.

Claims

1. A method for increasing oxygen vacancies on the surface of a tin oxide-doped target, characterized in that, Under vacuum and sintering temperatures of 1300-1600℃, tin oxide-doped target precursors and elemental titanium are placed in the same environment and held at that temperature for a period of time to obtain tin oxide-doped target materials. The metal oxides in the tin oxide-doped target precursors are tin oxide and doped metal oxides, and the amount of doped metal oxides is 2%-3% of the total molar amount of metal oxides. The doped metal oxide is molybdenum oxide or tungsten oxide.

2. The method for increasing oxygen vacancies on the surface of a tin oxide-doped target according to claim 1, characterized in that, The method is specifically as follows: Inside the sintering equipment, a quartz boat and a tin oxide-doped target precursor are placed, with powdered elemental titanium inside the quartz boat. The sintering equipment is evacuated and heated at a rate of 0.1-0.5℃ / min. After reaching the set temperature, it is held for 8-12 hours.

3. The method for increasing oxygen vacancies on the surface of a tin oxide-doped target according to claim 2, characterized in that, Tin oxide powder is spread inside the sintering equipment to improve thermal conductivity and prevent tin oxide-doped target precursors from sticking inside the sintering equipment.

4. The method for increasing oxygen vacancies on the surface of a tin oxide-doped target according to claim 1, characterized in that, The tin oxide-doped target precursor is prepared by the following method: Step 1: Mix tin oxide, doped metal oxide, dispersant, binder, and water, and grind to obtain a slurry; Step 2: Spray-dry the slurry to obtain powder; Step 3: Shape the powder; Step 4: Degrease and heat the product obtained in Step 3 to obtain tin oxide doped target precursor.

5. The method for increasing oxygen vacancies on the surface of a tin oxide-doped target according to claim 4, characterized in that, Step 1 is as follows: The doped metal oxide and the first dispersant were poured into a slurry tank containing pure water, dispersed evenly, and then wet-milled to obtain slurry one. Add the weighed tin oxide powder, pure water, and second dispersant to slurry one, disperse evenly, and then wet grind to obtain slurry two. Add a binder to slurry two, disperse it evenly, and then wet grind it to obtain slurry three.

6. The method for increasing oxygen vacancies on the surface of a tin oxide-doped target according to claim 5, characterized in that, The first dispersant accounts for 1-5% of the total mass of slurry one; the first dispersant is one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate or sodium hexadecylbenzenesulfonate; The second dispersant accounts for 1-15% of the total mass of the added tin oxide powder and the second dispersant; the second dispersant is one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate or sodium hexadecylbenzenesulfonate. The binder accounts for 5-15% of the total mass of the metal oxide and the binder; the binder is a mixture of polyvinyl alcohol and polyethylene glycol, polyvinyl alcohol or polyvinyl butyral, or one or both. The grinding speed for wet grinding of slurry one and slurry two is 1200-1800 r / min; the wet grinding time for slurry one is 8-15 h; and the wet grinding time for slurry two is 2-4 h.

7. The method for increasing oxygen vacancies on the surface of a tin oxide-doped target according to claim 5, characterized in that, The molding operations in step 3 are: sequential molding and cold isostatic pressing; The degreasing temperature in step 4 is 400℃-600℃, and the holding time is 6-12 hours.

8. A tin oxide doped target, characterized in that, It is prepared by the method described in any one of claims 1-7.