Gallium magnesium doped zinc oxide target material and preparation method thereof

Abstract

The invention belongs to the technical field of target material preparation, and discloses a gallium-magnesium-doped zinc oxide target material and a preparation method thereof.The preparation method of the gallium-magnesium-doped zinc oxide target material comprises the steps that 1, zinc oxide powder, gallium oxide powder and magnesium oxide powder are evenly mixed to obtain mixed powder; 2, the mixed powder is subjected to first-stage vacuum sintering; step 3, carrying out second-stage vacuum hot pressed sintering to obtain a gallium-magnesium doped zinc oxide target material; the particle size D90 of the zinc oxide powder is 3-4 [mu] m, and the particle size D90 of the gallium oxide powder and the magnesium oxide powder is 10-15 [mu] m; the total weight of the gallium oxide powder and the magnesium oxide powder is 1-5% of the weight of the mixed powder. By controlling the doping amount of gallium oxide and magnesium oxide, selecting the particle sizes of zinc oxide, magnesium oxide and gallium oxide and performing vacuum sintering for the first time in the step 2, the exhaust effect is improved, so that zinc oxide, magnesium oxide and gallium oxide with different particle sizes can be fully exhausted in the grain growth process, and the densification degree of the target material is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of target material preparation, and in particular to a gallium-magnesium-doped zinc oxide target material and a preparation method thereof. Background Art

[0002] Zinc oxide-based transparent semiconductor films have attracted widespread attention, as they not only have comparable optoelectronic properties to ITO films, but are also rich in resources, low in price, non-toxic and stable. In order to improve the performance of ZnO-based films, doping methods are currently used, such as aluminum doping to form AZO, gallium doping to form GZO, and magnesium doping to form ZMO. What's more, gallium and magnesium doping are used to form zinc oxide targets.

[0003] Prior art 1 adopts the above-mentioned gallium and magnesium doping method to prepare zinc oxide target material. Prior art 1: Chinese patent application 202011549209.5 discloses a magnesium-doped zinc oxide magnetron sputtering target material and a preparation method thereof, comprising the steps of: (1) doping magnesium oxide powder and a third oxide powder into zinc oxide powder, mixing the mixture with an ethanol solution to form a slurry; (2) ball-milling the slurry, drying it, and sieving it to obtain a powder for molding; (3) cold isostatically pressing the powder to form a green body; (4) slowly pressing the green body The temperature is rapidly raised to 900-1150° C., kept at this temperature for 30-90 min, then rapidly raised to a sintering temperature of 1300-1450° C., kept at this temperature for 120-480 min, and slowly cooled to form a semi-finished product; after cutting and grinding, the magnesium-doped zinc oxide magnetron sputtering target is obtained; wherein the third oxide powder can be selected from any one or more of titanium oxide, aluminum oxide, gallium oxide, indium oxide, cerium oxide, yttrium oxide, tin oxide, tungsten oxide, and molybdenum oxide; therefore, prior art 1 can also prepare gallium- and magnesium-doped zinc oxide targets.

[0004] The specification of prior art 1 records that the powder particle sizes of zinc oxide, magnesium oxide and the third oxide are 200-500mm, 10-200mm and 100-600mm respectively; it is explained that in prior art 1, zinc oxide powder with larger particle size, magnesium oxide with smaller particle size and third oxide powder with a wide particle size range are used to prepare the target material, and its technical advantages have been disclosed in the specification of prior art 2.

[0005] Prior art 2: Chinese patent application 202410989141.4 discloses a zinc oxide-based target material for RPD coating and a preparation method thereof. Its specification states: "Using large-particle zinc oxide powder as a skeleton helps to fill small-particle gallium magnesium zinc oxide solid solution powder into the voids of the skeleton zinc oxide powder, which can assist in molding. It not only helps to form a uniform and stable target blank after molding and improve the uniformity of the target material structure, but also has the advantages of low sintering activation energy and fast sintering rate, which helps to densify the blank and shorten the sintering time, thereby inhibiting the volatilization of ZnO."

[0006] It can be seen that the prior art 1 uses zinc oxide powder with a larger particle size to form a skeleton, and fills magnesium oxide and gallium oxide into the skeleton to improve the uniformity and density of the target material.

[0007] However, the prior art 1 uses nano-level powder to implement the technical solution. Nano-level powder is difficult to obtain and has high cost. For example, the raw material procurement cost will be greatly increased when mass production is carried out. Summary of the invention

[0008] One of the purposes of the present invention is to provide a method for preparing a gallium-magnesium doped zinc oxide target. By using the preparation method of the present invention and the selection of the powder particle sizes of zinc oxide, magnesium oxide and gallium oxide, a high-density target can be prepared using micron-level powders, thereby effectively reducing the raw material procurement cost.

[0009] Another object of the present invention is to provide a gallium-magnesium doped zinc oxide target material having an extremely high relative density to meet the needs of downstream products.

[0010] To achieve the above object, the present invention provides a method for preparing a gallium-magnesium doped zinc oxide target, comprising the following steps:

[0011] Step 1: uniformly mixing zinc oxide powder, gallium oxide powder and magnesium oxide powder to obtain a mixed powder;

[0012] Step 2: subjecting the mixed powder to the first stage of vacuum sintering;

[0013] Step 3: performing a second stage of vacuum hot pressing sintering to obtain a gallium-magnesium doped zinc oxide target;

[0014] The particle size D90 of the zinc oxide powder is 3-4 μm, and the particle sizes D90 of the gallium oxide powder and the magnesium oxide powder are 10-15 μm; the total weight of the gallium oxide powder and the magnesium oxide powder is 1-5% of the weight of the mixed powder.

[0015] Compared with nanometer-level zinc oxide, magnesium oxide, and gallium oxide, micrometer-level zinc oxide, magnesium oxide, and gallium oxide have larger overall particle sizes, and the relative density of the target materials prepared therefrom is lower; therefore, the present invention achieves the purpose of increasing the relative density of the target materials by controlling the particle sizes of zinc oxide, magnesium oxide, and gallium oxide powders at the micrometer level and combining them with a specific target material preparation method.

[0016] The present invention controls the doping amount of gallium oxide and magnesium oxide, selects the particle sizes of zinc oxide, magnesium oxide and gallium oxide, and performs the first vacuum sintering in step 2 to increase the exhaust effect, so that zinc oxide, magnesium oxide and gallium oxide with different particle sizes can be fully exhausted during the grain growth process, thereby improving the densification degree of the target material. Then, the target material is sintered through the second stage of vacuum hot pressing sintering to obtain a target material with a relatively high density.

[0017] Preferably, the weight ratio of gallium oxide powder to magnesium oxide powder is 2:3 or 3:2.

[0018] Preferably, in step 1, the zinc oxide powder, gallium oxide powder and magnesium oxide powder are mixed evenly by dry ball milling to obtain a mixed powder, wherein the ball-to-material ratio is 1.5-2:1 and the ball milling time is 8-10 hours.

[0019] Furthermore, the specific operation of step 2 is: heating the mixed powder to 500-600° C. under a vacuum degree of ≤10 Pa, and keeping the temperature for 30-60 minutes.

[0020] Preferably, the heating rate in step 2 is 3-5°C / min.

[0021] Furthermore, the specific operation of step 3 is: after the first stage of vacuum sintering in step 2 is completed, continue to heat to 900-1000°C and keep warm for 60-100 minutes. During the process, start pressurizing after keeping warm for 5 minutes until the end of the insulation, and the pressure is 60-90MPa.

[0022] Preferably, the heating rate in step 3 is 3-5°C / min.

[0023] The invention also discloses a gallium-magnesium doped zinc oxide target material, which is prepared by adopting the preparation method of the gallium-magnesium doped zinc oxide target material.

[0024] Beneficial Effects

[0025] Compared with the prior art, the present invention has at least the following advantages:

[0026] (1) The present invention controls the doping amount of gallium oxide and magnesium oxide, the particle size selection of zinc oxide, magnesium oxide, and gallium oxide, and performs the first vacuum sintering in step 2 to increase the exhaust effect, so that zinc oxide, magnesium oxide, and gallium oxide with different particle sizes can be fully exhausted during the grain growth process, thereby improving the densification degree of the target material, and then the target material is sintered through the second stage of vacuum hot pressing sintering to obtain a target material with a high relative density;

[0027] (2) The present invention adopts a staged heating and hot pressing method to prepare gallium-magnesium doped zinc oxide target material, which has high production efficiency and can effectively avoid the problem of low density caused by excessive grain size due to the use of micron-level raw material powder. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0029] In order to explain the technical content of the present invention in detail, further description is given below in conjunction with the implementation modes.

[0030] In the following examples and comparative examples, unless otherwise specified, the parts and % refer to parts by weight and percentage by weight, respectively.

[0031] Example 1

[0032] A gallium-magnesium doped zinc oxide target is prepared by the following steps:

[0033] Step 1: 96 parts of zinc oxide powder with a particle size D90 of 3.6 μm, 1 part of gallium oxide powder with a particle size D90 of 12.8 μm, and 3 parts of magnesium oxide powder with a particle size D90 of 12.1 μm were ball-milled for 10 hours to obtain a mixed powder, wherein the ball-to-material ratio was 2:1;

[0034] Step 2: Heat the mixed powder to 600°C at a heating rate of 5°C / min under a vacuum degree of ≤10Pa and keep the temperature for 30min;

[0035] Step 3: After step 2 is completed, continue to heat up to 950°C at a heating rate of 4°C / min and keep it warm for 100 minutes. During the process, pressurize after keeping warm for 5 minutes until the end of the heat preservation, and the pressure is 90MPa;

[0036] Step 4: Cooling in the furnace to obtain a gallium-magnesium doped zinc oxide target.

[0037] Example 2

[0038] A gallium-magnesium doped zinc oxide target is prepared by the following steps:

[0039] Step 1: 96 parts of zinc oxide powder with a particle size D90 of 3.4 μm, 2 parts of gallium oxide powder with a particle size D90 of 11.7 μm, and 2 parts of magnesium oxide powder with a particle size D90 of 13.2 μm were ball-milled for 10 hours to obtain a mixed powder, wherein the ball-to-powder ratio was 2:1;

[0040] Step 2: Heat the mixed powder to 600°C at a heating rate of 5°C / min under a vacuum degree of ≤10Pa and keep the temperature for 30min;

[0041] Step 3: After step 2 is completed, continue to heat up to 950°C at a heating rate of 4°C / min and keep it warm for 100 minutes. During the process, pressurize after keeping warm for 5 minutes until the end of the heat preservation, and the pressure is 90MPa;

[0042] Step 4: Cooling in the furnace to obtain a gallium-magnesium doped zinc oxide target.

[0043] Example 3

[0044] A gallium-magnesium doped zinc oxide target is prepared by the following steps:

[0045] Step 1: 95 parts of zinc oxide powder with a particle size D90 of 3.5 μm, 3 parts of gallium oxide powder with a particle size D90 of 11.9 μm, and 2 parts of magnesium oxide powder with a particle size D90 of 11.4 μm were ball-milled for 10 hours to obtain a mixed powder, wherein the ball-to-material ratio was 2:1;

[0046] Step 2: Heat the mixed powder to 600°C at a heating rate of 5°C / min under a vacuum degree of ≤10Pa and keep the temperature for 30min;

[0047] Step 3: After step 2 is completed, continue to heat up to 950°C at a heating rate of 4°C / min and keep it warm for 100 minutes. During the process, pressurize after keeping warm for 5 minutes until the end of the heat preservation, and the pressure is 90MPa;

[0048] Step 4: Cooling in the furnace to obtain a gallium-magnesium doped zinc oxide target.

[0049] Comparative Example 1

[0050] A gallium-magnesium doped zinc oxide target is prepared by the following steps:

[0051] Step 1: 95 parts of zinc oxide powder with a particle size D90 of 3.5 μm, 3 parts of gallium oxide powder with a particle size D90 of 11.9 μm, and 2 parts of magnesium oxide powder with a particle size D90 of 1.4 μm were ball-milled for 10 hours to obtain a mixed powder, wherein the ball-to-material ratio was 2:1;

[0052] Step 2: Heat the mixed powder to 600°C at a heating rate of 5°C / min under a vacuum degree of ≤10Pa and keep the temperature for 30min;

[0053] Step 3: After step 2 is completed, continue to heat up to 950°C at a heating rate of 4°C / min and keep it warm for 100 minutes. During the process, pressurize after keeping warm for 5 minutes until the end of the heat preservation, and the pressure is 90MPa;

[0054] Step 4: Cooling in the furnace to obtain a gallium-magnesium doped zinc oxide target.

[0055] Comparative Example 2

[0056] A gallium-magnesium doped zinc oxide target is prepared by the following steps:

[0057] Step 1: 95 parts of zinc oxide powder with a particle size D90 of 3.5 μm, 3 parts of gallium oxide powder with a particle size D90 of 2.9 μm, and 2 parts of magnesium oxide powder with a particle size D90 of 11.4 μm were ball-milled for 10 hours to obtain a mixed powder, wherein the ball-to-powder ratio was 2:1;

[0058] Step 2: Heat the mixed powder to 600°C at a heating rate of 5°C / min under a vacuum degree of ≤10Pa and keep the temperature for 30min;

[0059] Step 3: After step 2 is completed, continue to heat up to 950°C at a heating rate of 4°C / min and keep it warm for 100 minutes. During the process, pressurize after keeping warm for 5 minutes until the end of the heat preservation, and the pressure is 90MPa;

[0060] Step 4: Cooling in the furnace to obtain a gallium-magnesium doped zinc oxide target.

[0061] Comparative Example 3

[0062] A gallium-magnesium doped zinc oxide target is prepared by the following steps:

[0063] Step 1: 90 parts of zinc oxide powder with a particle size D90 of 3.5 μm, 8 parts of gallium oxide powder with a particle size D90 of 11.9 μm, and 2 parts of magnesium oxide powder with a particle size D90 of 11.4 μm were ball-milled for 10 hours to obtain a mixed powder, wherein the ball-to-material ratio was 2:1;

[0064] Step 2: Heat the mixed powder to 600°C at a heating rate of 5°C / min under a vacuum degree of ≤10Pa and keep the temperature for 30min;

[0065] Step 3: After step 2 is completed, continue to heat up to 950°C at a heating rate of 4°C / min and keep it warm for 100 minutes. During the process, pressurize after keeping warm for 5 minutes until the end of the heat preservation, and the pressure is 90MPa;

[0066] Step 4: Cooling in the furnace to obtain a gallium-magnesium doped zinc oxide target.

[0067] Comparative Example 4

[0068] A gallium-magnesium doped zinc oxide target is prepared by the following steps:

[0069] Step 1: 90 parts of zinc oxide powder with a particle size D90 of 3.5 μm, 3 parts of gallium oxide powder with a particle size D90 of 11.9 μm, and 7 parts of magnesium oxide powder with a particle size D90 of 11.4 μm were ball-milled for 10 hours to obtain a mixed powder, wherein the ball-to-material ratio was 2:1;

[0070] Step 2: Heat the mixed powder to 600°C at a heating rate of 5°C / min under a vacuum degree of ≤10Pa and keep the temperature for 30min;

[0071] Step 3: After step 2 is completed, continue to heat up to 950°C at a heating rate of 4°C / min and keep it warm for 100 minutes. During the process, pressurize after keeping warm for 5 minutes until the end of the heat preservation, and the pressure is 90MPa;

[0072] Step 4: Cooling in the furnace to obtain a gallium-magnesium doped zinc oxide target.

[0073] Comparative Example 5

[0074] A gallium-magnesium doped zinc oxide target is prepared by the following steps:

[0075] Step 1: 95 parts of zinc oxide powder with a particle size D90 of 3.5 μm, 3 parts of gallium oxide powder with a particle size D90 of 11.9 μm, and 2 parts of magnesium oxide powder with a particle size D90 of 11.4 μm were ball-milled for 10 hours to obtain a mixed powder, wherein the ball-to-material ratio was 2:1;

[0076] Step 2: cold isostatically press the mixed powder at 160 MPa and hold pressure for 30 seconds to obtain a green blank;

[0077] Step 3: The green blank is heated to the first sintering temperature of 950°C at a heating rate of 5°C / min, kept at this temperature for 30 minutes, and then heated to the second sintering temperature of 1400°C at a heating rate of 20°C / min, and kept at this temperature for 180 minutes;

[0078] Step 4: Cooling in the furnace to obtain a gallium-magnesium doped zinc oxide target.

[0079] Performance Testing

[0080] Relative density: Archimedean drainage method.

[0081] The relative density of the gallium-magnesium doped zinc oxide targets obtained in Examples 1-3 and Comparative Examples 1-5 was tested, and the results are shown in Table 1;

[0082] Table 1 Relative density results of gallium-magnesium doped zinc oxide targets obtained in Examples 1-3 and Comparative Examples 1-5

[0083]

[0084]

[0085] According to the data in Table 1:

[0086] According to the data of Examples 1-3, the present invention adopts a compound of zinc oxide, gallium oxide and magnesium oxide in a specific particle size range and a specific ratio, and combines the primary vacuum sintering and secondary hot pressing sintering process of the present invention to prepare a high relative density target material using micron-level powder. Compared with the technical solution of preparing a high relative density target material using micron-level powder, the technical solution of the present invention can greatly reduce the requirements for raw materials and reduce the cost of raw materials.

[0087] According to the data comparison between Example 3 and Comparative Examples 1 and 2, it can be seen that, based on the use of micron-level raw material powder, the particle size selection of magnesium oxide powder and the particle size matching of zinc oxide and gallium oxide powder have a relatively important influence on the relative density of the target material; and although the particle size selection of gallium oxide and the particle size matching of zinc oxide and magnesium oxide powder have a certain influence on the relative density of the target material, compared with Comparative Example 1, the influence is not very large.

[0088] According to the data comparison between Example 3 and Comparative Examples 3 and 4, it can be seen that when zinc oxide, gallium oxide and magnesium oxide are compounded in a specific particle size range and combined with the primary vacuum sintering and secondary hot pressing sintering of the present invention, the ratio of zinc oxide, magnesium oxide and gallium oxide will also have a significant effect on the relative density of the target material.

[0089] According to the data comparison of Example 3 and Comparative Example 5, it can be seen that the target material preparation method using cold isostatic pressing and sintering on the basis of a compound of zinc oxide, gallium oxide and magnesium oxide in a specific particle size range and a specific ratio cannot effectively prepare a target material with a relatively high density. It is necessary to combine the primary vacuum sintering and secondary hot pressing sintering process of the present invention to prepare a target material with a relatively high density.

[0090] The embodiments presented herein are only embodiments selected according to the combination of all possible embodiments. The appended claims should not be limited by the embodiments describing the present invention. Some numerical ranges used in the claims include sub-ranges therein, and the changes in these ranges should also be covered by the appended claims.

Claims

1. A method for preparing a gallium-magnesium doped zinc oxide target, characterized in that: The steps include: Step 1: uniformly mixing zinc oxide powder, gallium oxide powder and magnesium oxide powder to obtain a mixed powder; Step 2: subjecting the mixed powder to the first stage of vacuum sintering; Step 3: performing a second stage of vacuum hot pressing sintering to obtain a gallium-magnesium doped zinc oxide target; The particle size D90 of the zinc oxide powder is 3-4 μm, and the particle sizes D90 of the gallium oxide powder and the magnesium oxide powder are 10-15 μm; the total weight of the gallium oxide powder and the magnesium oxide powder is 1-5% of the weight of the mixed powder.

2. The method for preparing a gallium-magnesium doped zinc oxide target according to claim 1, characterized in that: In step 1, the zinc oxide powder, gallium oxide powder and magnesium oxide powder are mixed evenly by dry ball milling to obtain a mixed powder, wherein the ball-to-material ratio is 1.5-2:1 and the ball milling time is 8-10 hours.

3. The method for preparing a gallium-magnesium doped zinc oxide target according to claim 1, characterized in that: The specific operation of step 2 is: heating the mixed powder to 500-600° C. under a vacuum degree of ≤10 Pa, and keeping the temperature for 30-60 minutes.

4. The method for preparing a gallium-magnesium doped zinc oxide target according to claim 3, characterized in that: The heating rate is 3-5℃ / min.

5. The method for preparing a gallium-magnesium doped zinc oxide target according to claim 1, characterized in that: The specific operation of step 3 is: after the first stage of vacuum sintering in step 2 is completed, continue to heat up to 900-1000°C and keep warm for 60-100 minutes. During the process, start pressurizing after keeping warm for 5 minutes until the end of the insulation, and the pressure is 60-90MPa.

6. The method for preparing a gallium-magnesium doped zinc oxide target according to claim 5, characterized in that: The heating rate is 3-5℃ / min.

7. The method for preparing a gallium-magnesium doped zinc oxide target according to claim 1, characterized in that: The weight ratio of the gallium oxide powder to the magnesium oxide powder is 2:3 or 3:

2.

8. A gallium-magnesium doped zinc oxide target, characterized in that: The target is prepared by the method for preparing a gallium-magnesium doped zinc oxide target as described in any one of claims 1 to 7.

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