Preparation method of high-density indium oxide doped cerium titanium tantalum target

Abstract

The application belongs to the technical field of semiconductor and oxide target material, and discloses a preparation method of high-density indium oxide doped cerium titanium tantalum target material. The preparation method comprises the following steps: adding TiO2, Ta2O5, CeO2 and In2O3 powders, a dispersing agent, a binder and deionized water into a ball mill tank to perform wet ball milling, so as to obtain mixed slurry; drying, crushing, sieving the mixed slurry, and then performing calcination treatment at 600-800 DEG C under air atmosphere, and pressing into shape, so as to obtain a target blank; then, the target blank is placed into a vacuum device to perform vacuumizing treatment and oxygen charging treatment until the pressure is 60-100 KPa, the target material after the treatment is heated to 1450-1500 DEG C to perform sintering treatment, so as to obtain the high-density indium oxide doped cerium titanium tantalum target material. The target blank is subjected to vacuumizing treatment and oxygen charging treatment under a certain pressure before sintering, so that the relative density, bending strength and mobility of the target material can be significantly improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor and oxide target materials, and particularly relates to a preparation method of a high-density indium oxide doped cerium titanium tantalum target material. BACKGROUND

[0002] Transparent conductive oxide films are widely used in display, solar cell, light emitting diode, touch screen, gas sensor, microelectronic, vacuum electronic device and other fields due to their good metal-like conductivity, high glass-like light transmittance, high infrared reflectivity and other excellent semiconductor characteristics. Infrared transparent conductive films have important application value in military and civilian fields. For civilian fields, they can be applied in electronic and energy industries, sensing technology, optoelectronic technology and other fields, such as being used as infrared transparent electrodes in infrared solar cells and infrared lasers. For military fields, they can be applied in infrared imaging, spacecraft windows and other fields. Therefore, infrared transparent conductive films are very valuable materials.

[0003] Most of the existing transparent conductive oxide films are prepared by a target material of tin oxide doped indium oxide. Since tin replaces indium, the electron concentration of this target material is high, and the electron mobility is low, which leads to poor infrared band light transmittance of the transparent conductive oxide film prepared by this target material.

[0004] Diatantum pentoxide is a high-refractive-index coating material mainly used in lasers, optical communication and solar cell elements. Doping with elements such as cerium titanium tantalum can improve the corresponding performance of indium oxide target materials. In our previous patent CN116199496 A, the conductivity of the target material can be significantly improved by mixing and doping zinc oxide powder and rare metal oxides such as cerium oxide, titanium oxide, tantalum oxide, gallium oxide and germanium oxide powder. Patent CN 114180938 A discloses an indium oxide cerium titanium tantalum powder. By controlling the particle size of the mixed powder, the problem of uneven composition caused by the incorporation of large particle size rare metal elements into indium oxide can be avoided. Patent CN 116082045 A discloses a method for improving the performance of indium oxide titanium tantalum cerium. By mixing indium, titanium, tantalum and cerium stock solution with strong alkaline precipitating agent to generate indium hydroxide, titanium, tantalum and cerium precipitate, and then through drying, grinding, calcination and other processes, an indium oxide titanium tantalum cerium powder with higher particle uniformity is prepared. The particle size of the indium oxide titanium tantalum cerium precursor is controlled, so that the indium oxide titanium tantalum cerium powder generated after calcination has better particle uniformity.

[0005] The above prior arts improve the corresponding conductivity, uniformity and density from the aspects of doping elements or mixed powder particle size control. There is no corresponding study on the influence of sintering process condition control on the relative density, bending strength and mobility of the target material. SUMMARY

[0006] In view of the defects and deficiencies of the above prior arts, the primary object of the present application is to provide a preparation method of high-density indium oxide doped cerium titanium tantalum target material.

[0007] Another object of the present application is to provide a high-density indium oxide doped cerium titanium tantalum target material prepared by the above method.

[0008] The object of the present application is achieved by the following technical solutions.

[0009] A preparation method of high-density indium oxide doped cerium titanium tantalum target material, comprising the following preparation steps:

[0010] (1) adding titanium oxide (TiO2), tantalum pentoxide (Ta2O5), cerium oxide (CeO2) and indium oxide (In2O3) powders, a dispersing agent, a binder and deionized water into a ball mill tank for wet ball milling to obtain a mixed slurry;

[0011] (2) drying, crushing, sieving the mixed slurry obtained in step (1), and then calcining at a temperature of 600-800°C in an air atmosphere, and pressing to form a target blank;

[0012] (3) placing the target blank obtained in step (2) into a vacuum device for vacuumizing treatment, and then performing oxygen charging treatment until the pressure is 60-100 KPa;

[0013] (4) placing the target material treated in step (3) into a sintering furnace, heating to 1450-1500°C, and performing sintering treatment under normal pressure air condition to obtain a high-density indium oxide doped cerium titanium tantalum target material.

[0014] Preferably, the molar ratio of In2O3:TiO2:Ta2O5:CeO2 in step (1) is 81-87:2-8:1-3:5-11.

[0015] Preferably, the dispersing agent in step (1) is one or more of polyvinylpyrrolidone, polycarboxylic acid compound and polyvinyl acetate.

[0016] Preferably, the binder in step (1) is one or more of polyvinyl alcohol, carboxymethyl cellulose, polyacrylamide, polyacrylic acid salt and polyethylene glycol.

[0017] Preferably, the particle size D50 of the mixed slurry in step (1) is less than 0.5 μm, and the particle size D90 is less than 1 μm.

[0018] Preferably, the temperature in step (2) is 100-120 DEG C; the sieving is through 60-80 mesh.

[0019] Preferably, the time in step (2) is 2-3 h.

[0020] Preferably, the pressing in step (2) is through 30-60 MPa hydraulic forming and 350-450 MPa cold isostatic pressing.

[0021] Preferably, the vacuumizing in step (3) reaches 10 -4 ~ 10 -3 Pa.

[0022] Preferably, the oxygen in step (3) is not less than 99.99% in purity and less than 5 ppm in water content; the holding time of the oxygenizing is 30-60 min.

[0023] Preferably, the sintering in step (4) is first heated to 600-800 DEG C at 0.5-1 DEG C / min and kept for 2-3 h, then heated to 1450-1500 DEG C at 0.8-1.2 DEG C / min and kept for 8-10 h.

[0024] A high-density indium oxide doped cerium titanium tantalum target material is prepared by the above method.

[0025] Preferably, the relative density of the high-density indium oxide doped cerium titanium tantalum target material is not less than 99.5%, the bending strength is not less than 182 MPa, and the mobility is not less than 75%.

[0026] The principle of the application is that the voids of the target blank are not conducive to the densification of the sintering process of the target material, the oxygen in the voids is filled by the oxygenizing after vacuumizing, the oxygen in the voids can inhibit the decomposition and volatilization of the target material in the sintering process, thereby improving the density and shortening the holding time; the target material has oxygen vacancies, the oxygen in the voids is more easily diffused through the oxygen vacancies and the grain boundary zone of the material to make the grain boundary over-oxidized or oxygen "segregated" and finally diffused and eliminated, the grain is not too large to affect the performance of the target material, and the target material has certain advantages in improving the mobility of the film in the later sputtering process of the target material; the target material component adds tantalum oxide, which cooperates with other components in the sintering process to make the final bending strength of the target material have certain advantages.

[0027] Compared with the prior art, the application has the following advantages:

[0028] (1) The In-doped Ce-Ti-Ta target material prepared by the method has high density and good uniformity of composition, so that the light transmittance of the conductive oxide thin film using the target material in the infrared band is improved, and the conductive performance is excellent, which does not affect the use as a conductive electrode, and the other physical and chemical performances of the thin film are consistent with those of the traditional indium tin oxide (ITO) thin film.

[0029] (2) The relative density, bending strength and mobility of the target material can be significantly improved by the vacuumizing treatment and oxygen filling treatment under pressure on the target blank before sintering. DETAILED DESCRIPTION

[0030] The application will be further described in detail below in combination with examples, but the embodiments of the application are not limited thereto.

[0031] Example 1

[0032] (1) Oxide powders are weighed according to the molar fraction of In2O3:TiO2:Ta2O5:CeO2=0.81:0.08:0.03:0.08, that is, 224.88g In2O3, 6.38g TiO2, 13.25g Ta2O5 and 13.76g CeO2. Then, 77.49g deionized water, 2.58g polyvinylpyrrolidone dispersant and 2.58g polyvinyl alcohol binder are added into a ball mill tank for ball milling for 12h to obtain a mixed slurry with D50=0.36μm and D90=0.90μm.

[0033] (2) The mixed slurry obtained in step (1) is dried and crushed at a temperature of 110℃, and then sieved through an 80-mesh sieve; then, the sieved powder is calcined at a temperature of 600℃ in an air atmosphere for 3h; and then, the calcined powder is subjected to liquid pressure forming and cold isostatic pressing to obtain a target blank. In the liquid pressure forming process, the pressure used is 35MPa; and in the cold isostatic pressing process, the pressure used is controlled to be 380MPa.

[0034] (3) The target blank obtained in step (2) is placed into a vacuum device for vacuumizing treatment, and then slowly filled with oxygen, wherein the vacuum degree of the vacuumizing treatment is 10 -4 Pa, the pressure of the filled oxygen is 100KPa, the oxygen purity is 99.99%, and the water content is less than 5ppm.

[0035] (4) The target blank obtained in step (3) is placed into a sintering furnace, heated to 600℃ at a rate of 0.5℃ / min, kept for 2h, and then heated to 1450℃ at a rate of 0.9℃ / min, kept for 10h, naturally cooled to 100℃, and then taken out after the furnace door is opened and the temperature is reduced to room temperature.

[0036] The target material after being discharged from the furnace in this example was mechanically processed and cleaned by using a water cutting device and a surface grinder. The relative density of the target material was 99.58% as measured by the Archimedes drainage method, the bending strength was 182 MPa, and the mobility reached 75.2%.

[0037] Example 2

[0038] (1) Oxide powders were weighed according to the molar fractions of In2O3:TiO2:Ta2O5:CeO2=0.83:0.03:0.03:0.11, i.e. 230.44 g of In2O3, 2.39 g of TiO2, 13.25 g of Ta2O5, and 18.93 g of CeO2. Then, 92.75 g of deionized water, 7.95 g of polycarboxylate dispersant, and 5.30 g of carboxymethyl cellulose binder were added into a ball mill tank for ball milling for 15 h to obtain a mixed slurry with a D50 of 0.34 μm and a D90 of 0.78 μm.

[0039] (2) The mixed slurry obtained in step (1) was dried and crushed at a temperature of 110°C, and then sieved through a 80-mesh sieve. Then, the sieved powder was calcined at a temperature of 700°C in an air atmosphere for 2 h. The calcined powder was subjected to hydrostatic forming and cold isostatic pressing to obtain a target blank. In the hydrostatic forming process, a pressure of 40 MPa was used; in the cold isostatic pressing process, a pressure of 350 MPa was used.

[0040] (3) The target blank obtained in step (2) was placed into a vacuum device for vacuumizing treatment, and then slowly filled with oxygen. The vacuumizing treatment was performed at a vacuum degree of 10 -4 Pa, the oxygen filling was performed at a pressure of 80 KPa for 40 min, the oxygen purity was 99.99%, and the water content was less than 5 ppm.

[0041] (4) The target blank obtained in step (3) was placed into a sintering furnace, and then heated to 700°C at a rate of 0.8°C / min, and kept at this temperature for 3 h. Then, the temperature was continuously increased to 1500°C at a rate of 0.9°C / min, and kept at this temperature for 8 h. After natural cooling to 100°C, the furnace door was opened, and the target material was taken out after cooling to room temperature.

[0042] The target material after being discharged from the furnace in this example was mechanically processed and cleaned by using a water cutting device and a surface grinder. The relative density of the target material was 99.58% as measured by the Archimedes drainage method, the bending strength was 182 MPa, and the mobility reached 75.2%.

[0043] Example 3

[0044] (1) Take oxide powders according to the molar fraction of In2O3:TiO2:Ta2O5:CeO2=0.86:0.05:0.02:0.07, i.e. 238.77 g of In2O3, 3.99 g of TiO2, 8.83 g of Ta2O5, and 12.04 g of CeO2. Then add 105.46 g of deionized water, 5.27 g of polycarboxylate dispersant, and 7.90 g of polyacrylamide binder into a ball mill tank and ball mill for 16 h to obtain a mixed slurry with D50=0.42 μm and D90=0.76 μm.

[0045] (2) Dry and crush the mixed slurry obtained in step (1) at a temperature of 110°C and pass through an 80-mesh sieve; then perform calcination treatment at a temperature of 800°C for 2 h in an air atmosphere; and perform hydraulic forming and cold isostatic pressing on the calcined powder to obtain a target blank. In the process of hydraulic forming, the pressure used is 50 MPa; and in the process of cold isostatic pressing, the pressure used is controlled to be 450 MPa.

[0046] (3) Place the target blank obtained in step (2) into a vacuum device to perform vacuum treatment, and then slowly fill in oxygen, wherein the vacuum degree of the vacuum treatment is 10 -3 Pa, the pressure of the filled-in oxygen is 60 KPa, the oxygen purity is 99.99%, and the water content is less than 5 ppm.

[0047] (4) Place the target blank obtained in step (3) into a sintering furnace, heat to 800°C at a rate of 0.6°C / min, keep for 3 h, continue to heat to 1480°C at a rate of 1°C / min, keep for 9 h, naturally cool to 100°C, open the furnace door, and take out the target after cooling to room temperature.

[0048] Mechanically process and clean the target taken out of the furnace in this example by using a water cutting device and a surface grinding machine, and measure the relative density of the target by the Archimedes drainage method to be 99.60%, the bending strength to be 186 MPa, and the mobility to be 75.8%.

[0049] Example 4

[0050] (1) Take oxide powders according to the molar fraction of In2O3:TiO2:Ta2O5:CeO2=0.87:0.02:0.01:0.1, i.e. 241.54 g of In2O3, 1.59 g of TiO2, 4.41 g of Ta2O5, and 17.21 g of CeO2. Then add 92.67 g of deionized water, 7.94 g of polyvinylpyrrolidone dispersant, and 5.29 g of polyvinyl alcohol binder into a ball mill tank and ball mill for 20 h to obtain a mixed slurry with D50=0.30 μm and D90=0.75 μm.

[0051] (2) The mixed slurry obtained in step (1) is dried and crushed at a temperature of 110°C, and then sieved through a 60-mesh sieve; then the sieved powder is calcined in an air atmosphere at a temperature of 700°C for 3 hours; the calcined powder is subjected to hydrostatic forming and cold isostatic pressing to obtain a target blank. In the hydrostatic forming process, the pressure used is 60 MPa; in the cold isostatic pressing process, the pressure used is controlled to be 400 MPa.

[0052] (3) The target blank obtained in step (2) is placed in a vacuum device for vacuumizing treatment, and then slowly filled with oxygen, wherein the vacuum degree of the vacuumizing treatment is 10 -3 Pa, the pressure of the filled oxygen is 70 KPa, the oxygen purity is 99.99%, and the water content is less than 5 ppm, and the holding time is 50 minutes.

[0053] (4) The target blank obtained in step (3) is placed in a sintering furnace, and heated to 800°C at a rate of 1°C / min, and held for 2 hours; then heated to 1480°C at a rate of 0.8°C / min, and held for 8 hours; then naturally cooled to 100°C, and then the furnace door is opened, and the target material is taken out after cooling to room temperature.

[0054] The target material after being taken out of the furnace is mechanically processed and cleaned by using a water cutting device and a surface grinding machine, and the relative density of the target material is measured by the Archimedes drainage method to be 99.61%, the bending strength is 193 MPa, and the mobility is 75.9%.

[0055] Comparative Example 1

[0056] The comparative example is the same as Example 1 except that the vacuumizing treatment and oxygen filling process in step (3) are not performed.

[0057] The target material after being taken out of the furnace is mechanically processed and cleaned by using a water cutting device and a surface grinding machine, and the relative density of the target material is measured by the Archimedes drainage method to be 95.50%, the bending strength is 143 MPa, and the mobility is 63.8%.

[0058] Comparative Example 2

[0059] The comparative example is the same as Example 1 except that the pressure of the oxygen filling process in step (3) is 30 KPa.

[0060] The target material after being taken out of the furnace is mechanically processed and cleaned by using a water cutting device and a surface grinding machine, and the relative density of the target material is measured by the Archimedes drainage method to be 96.80%, the bending strength is 150 MPa, and the mobility is 65.3%.

[0061] Comparative Example 3

[0062] The comparative example is the same as Example 1 except that the pressure of the oxygen filling process in step (3) is 40 KPa.

[0063] The target material after being discharged from the furnace was mechanically processed and cleaned by using a water cutting device and a surface grinder. The relative density of the target material was 97.56% as measured by the Archimedes drainage method, the bending strength was 154 MPa, and the mobility was 66.6%.

[0064] Comparative Example 4

[0065] Comparative Example 4 was the same as Example 1 except that the pressure of the oxygenation treatment in step (3) was 150 KPa.

[0066] The target material after being discharged from the furnace was mechanically processed and cleaned by using a water cutting device and a surface grinder. The relative density of the target material was 99.58% as measured by the Archimedes drainage method, the bending strength was 180 MPa, and the mobility was 74.8%.

[0067] The performance test results of the target materials obtained in Examples 1-4 and Comparative Examples 1-4 are shown in Table 1 below.

[0068] Table 1

[0069]

[0070]

[0071] As shown in Table 1, the relative density, the bending strength, and the mobility of the target material can be significantly improved by performing vacuum treatment and oxygenation treatment at a certain pressure (60-100 KPa) on the target blank before sintering. When the pressure of the oxygenation treatment exceeds 100 KPa, the improvement of the target material decreases, and the cost increases.

[0072] The above examples are preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples. Any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods, and are included in the protection scope of the present application.

Claims

1. A method for preparing a high-density indium oxide-doped cerium-titanium-tantalum target, characterized in that, The preparation steps include the following: (1) TiO2, Ta2O5, CeO2, In2O3 powders, along with dispersant, binder, and deionized water, were added to a ball mill jar for wet ball milling to obtain a mixed slurry; the molar ratio of each oxide powder added was In2O3: TiO2: Ta2O5: CeO2 = 81~87: 2~8: 1~3: 5~11; (2) The mixed slurry obtained in step (1) is dried, crushed, and sieved, and then calcined in air at a temperature of 600~800℃, and pressed into shape to obtain a target blank; (3) The target blank obtained in step (2) is placed in a vacuum device for vacuum treatment, and then oxygenated until the pressure is 60~100KPa; the vacuum treatment makes the vacuum degree reach 10 -4 ~10 -3 Pa; the oxygen purity of the oxygenation treatment is not less than 99.99%, and the water content is less than 5 ppm; the oxygenation treatment time is 30~60 min; (4) The target material after step (3) is placed in a sintering furnace and heated to 1450~1500℃ and sintered under normal air pressure to obtain a high-density indium oxide doped cerium titanium tantalum target material.

2. The method for preparing a high-density indium oxide-doped cerium-titanium-tantalum target according to claim 1, characterized in that, The dispersant in step (1) is one or more of polyvinylpyrrolidone, polycarboxylic acid compounds, and polyvinyl salts; the binder is one or more of polyvinyl alcohol, carboxymethyl cellulose, polyacrylamide, polyacrylate, and polyethylene glycol.

3. The method for preparing a high-density indium oxide-doped cerium-titanium-tantalum target according to claim 1, characterized in that, The particle size of the mixed slurry in step (1) is D50 < 0.5 μm and D90 < 1 μm.

4. The method for preparing a high-density indium oxide-doped cerium-titanium-tantalum target according to claim 1, characterized in that, The drying temperature in step (2) is 100~120℃; the sieving refers to passing through a 60~80 mesh sieve; the calcination time is 2~3 h.

5. The method for preparing a high-density indium oxide-doped cerium-titanium-tantalum target according to claim 1, characterized in that, The pressing molding mentioned in step (2) refers to sequential hydraulic molding at 30~60MPa and cold isostatic pressing at 350~450MPa.

6. The method for preparing a high-density indium oxide-doped cerium-titanium-tantalum target according to claim 1, characterized in that, The sintering process described in step (4) is as follows: first, the temperature is raised to 600-800℃ at 0.5-1℃ / min and held for 2-3 hours, then the temperature is raised to 1450-1500℃ at 0.8-1.2℃ / min and held for 8-10 hours.

7. A high-density indium oxide-doped cerium-titanium-tantalum target, characterized in that, It is prepared by the method described in any one of claims 1 to 6.

8. The high-density indium oxide-doped cerium-titanium-tantalum target material according to claim 7, characterized in that, The high-density indium oxide doped cerium titanium tantalum target has a relative density ≥99.5%, a bending strength ≥182MPa, and a mobility ≥75%.

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