A method for preparing a zinc gallate target material and a zinc gallate target material

Abstract

The application discloses a preparation method of a zinc gallate target material and the zinc gallate target material. The preparation method of the zinc gallate target material comprises the following steps: 1) mixing zinc oxide powder and gallium oxide powder to obtain mixed powder, mixing the mixed powder with a solvent, and obtaining slurry through ball milling; 2) drying the slurry and grinding into powder; 3) pressing the powder into a green body; 4) performing first sintering on the green body to obtain a semi-finished target material, and the first sintering temperature is 1250-1650 DEG C; and 5) performing second sintering on the semi-finished target material in an inverted mode to obtain the zinc gallate target material, and the second sintering temperature is 800-1300 DEG C and is lower than the first sintering temperature. After the first sintering of the target material, the zinc gallate target material is subjected to the second high-temperature sintering with the zinc-rich surface upward, so that the component distribution of the zinc gallate target material is more uniform, the oxide thin film crystal quality and process stability of the zinc gallate target material are improved, and the zinc gallate target material is suitable for industrial production.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor material preparation technology, and in particular to a method for preparing a zinc gallate target and a zinc gallate target. Background Technology

[0002] With the advancement of the information society, ultra-wide bandgap semiconductors, as a high-performance electronic material, have received increasing attention and application. Ultra-wide bandgap semiconductor devices can operate in extreme environments such as high temperature, high pressure, and high frequency, making them suitable for high-end applications in fields such as rail transportation, semiconductor lighting, high-voltage power transmission and transformation, and ultraviolet detection. Therefore, they have become a hot topic in international semiconductor device and material research and industrialization. Among the many ultra-wide bandgap semiconductor materials, zinc gallate (ZnGa2O4) is an emerging material with an ultra-wide bandgap (~4.5 eV), high electron mobility, and excellent thermal stability. Therefore, it has broad application potential in solar-blind ultraviolet detection and power devices, attracting widespread interest from researchers. Zinc gallate has a spinel-type crystal structure, belonging to the face-centered cubic lattice of the cubic crystal system, with a space group of Fd3m and a lattice constant of... In the spinel structure, oxygen ions are arranged in a cubic close-packed pattern, forming tetrahedrons and octahedrons. Zinc ions occupy one-eighth of the tetrahedral interstices, and gallium ions occupy one-half of the octahedral interstices, thus forming the basic unit of zinc gallate. Because the vapor pressure of zinc (Zn) is much higher than that of gallium (Ga), in physical vapor deposition techniques (such as pulsed laser deposition and magnetron sputtering), the use of stoichiometric targets during film deposition leads to a significant amount of zinc atoms volatilizing, resulting in a Zn / Ga atomic ratio less than 1:2. This affects the crystal structure, band structure, and electrical properties of the material, adversely impacting film quality and performance. To avoid the impact of zinc volatilization on film structure and electrical properties, a common method is to use zinc-rich zinc gallate targets, i.e., increasing the zinc content in the target to achieve a Zn / Ga atomic ratio greater than 1:2. This ensures that even with zinc atom volatilization during high-temperature deposition, the stoichiometric ratio in the prepared film remains at or near 1:2, resulting in high-quality zinc gallate films.

[0003] Zinc gallate targets are prepared by uniformly mixing gallium oxide (Ga₂O₃) powder and zinc oxide (ZnO) powder, followed by solid-state reaction sintering at high temperatures. During high-temperature sintering, the increased thermal motion between atoms or molecules leads to a denser structure, causing the target to shrink towards the center and bottom. Because zinc-rich zinc gallate targets contain excess zinc oxide during high-temperature sintering, and zinc oxide shrinks more than zinc gallate at high temperatures, zinc oxide accumulates on the lower surface of the sintered target. This results in a gradual decrease in zinc content from the lower to the upper surface, leading to an uneven composition distribution in the prepared zinc-rich zinc gallate target. Summary of the Invention

[0004] This disclosure provides a method for preparing a zinc gallate target and a zinc gallate target, in order to at least solve one of the technical problems existing in the prior art.

[0005] According to a first aspect of this disclosure, a zinc gallate target is provided, comprising the following steps:

[0006] Step 1): Zinc oxide powder and gallium oxide powder are mixed to obtain a mixed powder. The mixed powder is then mixed with a solvent and ball-milled to obtain a slurry.

[0007] Step 2): Dry the slurry and then grind it into powder;

[0008] Step 3): Press the powder into a raw blank;

[0009] Step 4): The green blank is sintered for the first time to obtain a semi-finished target material, wherein the first sintering temperature is 1250~1650℃;

[0010] Step 5): The semi-finished target material obtained in step 4) is inverted and subjected to a second sintering to obtain the zinc gallate target material. The second sintering temperature is 800-1300℃, and the second sintering temperature is lower than the first sintering temperature.

[0011] In one embodiment, in step 5), the second sintering time is 4 to 10 hours.

[0012] In one embodiment, in step 5), the temperature is increased to the second sintering temperature at a heating rate of 3-8°C / min.

[0013] In one embodiment, in step 5), a first heat preservation is performed before the second sintering. The first heat preservation temperature is 700-1000°C, and the first heat preservation temperature is less than or equal to the second sintering temperature.

[0014] In one embodiment, in step 5), the temperature is increased from room temperature to the first holding temperature at a heating rate of 3-10°C / min, and the holding time is 30-90 min; then the temperature is increased to the second sintering temperature at a heating rate of 3-8°C / min, and sintering is continued for 4-10 h; then the temperature is decreased to the second holding temperature at a cooling rate of 3-8°C / min, the second holding temperature is 700°C-1000°C and the second holding temperature is lower than the second sintering temperature, and the temperature is held for 30 min; finally, the temperature is decreased to room temperature at a cooling rate of 3-8°C / min.

[0015] In one embodiment, in step 1), zinc oxide powder and gallium oxide powder are weighed according to a mass ratio of zinc oxide to gallium oxide of 3:7 to 7:3, and then the two are mixed to obtain a mixed powder. The mixed powder is added to a solvent and then ball-milled for 6 to 10 hours to obtain a grinding slurry.

[0016] In one embodiment, in step 1), the mass ratio of the solvent to the mixed powder is 1:2 to 2:1;

[0017] The solvent is alcohol or deionized water.

[0018] In one embodiment, in step 2), the drying is performed by constant temperature heating at 80-150°C for 2-6 hours.

[0019] In one embodiment, in step 3), the green blank is obtained by cold isostatic pressing at a pressure of 100-500 MPa for 5-10 minutes.

[0020] The relative density of the green blank is 53% to 62%.

[0021] In one embodiment, in step 4), the first sintering time is 6 to 12 hours, and the first sintering time is greater than or equal to the second sintering time.

[0022] In one embodiment, in step 4), the temperature is increased to the first sintering temperature at a heating rate of 3 to 8 °C / min.

[0023] In one embodiment, in step 4), the green blank is placed in a high-temperature tube furnace, and starting from room temperature, the temperature is increased to 1000°C at a heating rate of 3-10°C / min, held for 30-90 minutes, and then increased to the first sintering temperature at a heating rate of 3-8°C / min, and sintered for 6-12 hours; then the temperature is decreased to 1000°C at a cooling rate of 3-8°C / min and held for 30-90 minutes; finally, the temperature is decreased to room temperature at a cooling rate of 3-8°C / min.

[0024] Secondly, this application provides a zinc gallate target material, which is prepared by the preparation method in any of the embodiments of the first aspect.

[0025] Compared with existing technologies, the advantages of this application are as follows: After the first sintering of the target material, this application performs a second high-temperature sintering with the zinc-rich side of the target material facing upwards. This results in a more uniform composition distribution in the sintered zinc gallate target material, improving the crystal quality and process stability of the oxide thin film using the zinc gallate target material. Furthermore, the production process is simple and suitable for industrial production. This application employs a two-stage high-temperature sintering technology. After the first sintering of the target material, a second high-temperature sintering is performed with the zinc-rich side facing upwards. This second inverted sintering further enhances the uniformity of the internal composition of the target material, resulting in a zinc gallate target material with uniform zinc and gallium composition.

[0026] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0027] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which:

[0028] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0029] Figure 1 A schematic diagram of the preparation process of the zinc gallate target according to an embodiment of the present disclosure is shown;

[0030] Figure 2 Photographs of the upper and lower surfaces of the zinc gallate target according to Embodiment 1 of this disclosure are shown;

[0031] Figure 3 A schematic diagram showing the sampling test points A, B, and C of the zinc gallate target according to an embodiment of the present disclosure is provided.

[0032] Figure 4 The energy dispersive X-ray spectrum of the zinc gallate target prepared in Example 1 of this disclosure is shown;

[0033] Figure 5 The energy dispersive X-ray spectrum of the zinc gallate target prepared in Example 2 of this disclosure is shown;

[0034] Figure 6 The energy dispersive X-ray spectrum of the zinc gallate target prepared in Comparative Example 1 of this disclosure is shown;

[0035] Figure 7 Photographs of the upper and lower surfaces of the zinc gallate target of Comparative Example 2 of this disclosure are shown;

[0036] Figure 8A photograph of the zinc gallate target of Comparative Example 3 of this disclosure is shown. Detailed Implementation

[0037] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0038] This application provides a method for preparing a zinc gallate target, including,

[0039] Step 1): Zinc oxide powder and gallium oxide powder are mixed to obtain a mixed powder. The mixed powder is then mixed with a solvent and ball-milled to obtain a slurry.

[0040] Step 2): Dry the slurry and then grind it into powder;

[0041] Step 3): Press the powder into a raw blank;

[0042] Step 4): The green blank is sintered for the first time to obtain a semi-finished target material. The first sintering temperature is 1250-1650℃. The zinc composition inside the semi-finished target material is not uniform. The zinc composition inside the semi-finished target material gradually increases from the upper surface to the lower surface, and the lower surface is a zinc-rich surface.

[0043] Step 5) The semi-finished target material obtained in step 4) is inverted (i.e., zinc-rich side facing up) and subjected to a second sintering to obtain a zinc gallate target material. The second sintering temperature is 800–1300℃, and is lower than the first sintering temperature. After inverting the semi-finished target material with the zinc-rich side facing up, a certain gradient of zinc composition has already formed from top to bottom within the target material during the first sintering process. During the second sintering process, after the target material is inverted, the zinc composition continues to diffuse from top to bottom. However, the second sintering temperature and time are not high or long enough (i.e., the second sintering time is less than or equal to the first sintering time), resulting in a very low zinc diffusion coefficient and a slow zinc migration rate, completely compensating for the zinc concentration gradient formed during the first target sintering. This results in a uniform distribution of zinc and gallium components within the final zinc gallate target material. The zinc composition in the final zinc gallate target material is uniform, with a deviation of 0–10%. Furthermore, in the zinc gallate target prepared by this method, the atomic ratio of zinc to gallium is greater than 1:2.

[0044] In one embodiment, in step 5), the second sintering time is 4 to 10 hours.

[0045] In one embodiment, in step 5), the temperature is increased to the second sintering temperature at a heating rate of 3-8°C / min. Preferably, the temperature is increased to the second sintering temperature at a heating rate of 5°C / min.

[0046] In one embodiment, in step 5), a first heat preservation is performed before the second sintering. The first heat preservation temperature is 700-1000°C and is less than or equal to the second sintering temperature.

[0047] In one embodiment, in step 5), the temperature is increased from room temperature to the first holding temperature at a heating rate of 3–10 °C / min, and held for 30–90 min; then the temperature is increased to the second sintering temperature at a heating rate of 3–8 °C / min, and sintering is continued for 4–10 h; subsequently, the temperature is decreased to the second holding temperature at a cooling rate of 3–8 °C / min, which is 700 °C–1000 °C and lower than the second sintering temperature, and held for 30 min; finally, the temperature is decreased to room temperature at a cooling rate of 3–8 °C / min. In step 5), the first holding temperature before the second sintering can be equal to or lower than the second sintering temperature. When the first holding temperature and the second sintering temperature are equal, when the temperature is increased to the first holding temperature at a heating rate of 3–10 °C / min, after holding for a period of time, sintering is directly carried out at this holding temperature for 4–10 h.

[0048] In one embodiment, in step 1), zinc oxide powder and gallium oxide powder are weighed in a mass ratio of 3:7 to 7:3, and the two are mixed to obtain a mixed powder. The mixed powder is added to a solvent and then ball-milled for 6 to 10 hours to obtain a grinding slurry.

[0049] In one embodiment, in step 1), the mass ratio of solvent to mixed powder is 1:2 to 2:1; the solvent is alcohol or deionized water.

[0050] In one embodiment, in step 2), drying is performed by constant heating at 80–150°C for 2–6 hours.

[0051] In one embodiment, in step 3), cold isostatic pressing is maintained at a pressure of 100-500 MPa for 5-10 minutes to obtain a green blank;

[0052] The relative density of the green body is 50%–62%.

[0053] In one embodiment, in step 4), the first sintering time is 6 to 12 hours, and the first sintering time is greater than or equal to the second sintering time.

[0054] In one embodiment, in step 4), the temperature is increased to the first sintering temperature at a heating rate of 3 to 8 °C / min.

[0055] In one embodiment, in step 4), the green blank is placed in a high-temperature tube furnace. Starting from room temperature, the temperature is increased to 1000°C at a rate of 3–10°C / min, held for 30–90 minutes, and then increased to the first sintering temperature at a rate of 3–8°C / min, and sintered for 6–12 hours. Then, the temperature is decreased to 1000°C at a rate of 3–8°C / min and held for 30–90 minutes. Finally, the temperature is decreased to room temperature at a rate of 3–8°C / min. Holding the temperature for a period before the first sintering prevents the powder from volatilizing due to rapid temperature increases. Holding the temperature for a period before sintering results in better sintering performance.

[0056] Secondly, this application provides a zinc gallate target material, which is prepared by the preparation method in any of the above embodiments.

[0057] The following is a specific application scenario: a method for preparing a zinc gallate target, including the following steps:

[0058] Step S1: Weigh zinc oxide powder and gallium oxide powder in a mass ratio of 3:7 to 7:3. Mix the zinc oxide powder and gallium oxide powder to obtain a mixed powder. Pour the mixed powder into alcohol or deionized water in a mass ratio of 1:2 to 2:1 and then ball mill for 6 to 10 hours to obtain a grinding slurry.

[0059] Step S2: Pour the slurry into a petri dish or other high-temperature resistant container, then place it in an oven or heating table and heat it at a constant temperature of 80-150℃ for 2-6 hours. After the slurry is dried, grind it into powder.

[0060] Step S3: Pour the powder into the mold, then place it in the press and hold it under static pressure of 100MPa to 500MPa for 5 to 10 minutes to obtain the green blank. The relative density of the green blank is 50% to 62%.

[0061] Step S4: Place the green billet into a high-temperature tube furnace and start heating from room temperature at a rate of 3℃ / min to 10℃ / min. After reaching 1000℃, hold at that temperature for 30min to 90min. Then, heat to 1250℃ to 1650℃ at a rate of 3℃ / min to 8℃ / min and continue sintering for 6 to 12 hours. Then, start cooling at a rate of 5℃ / min and hold at 1000℃ for 30min to 90min. Finally, cool to room temperature at a rate of 3℃ / min to 8℃ / min. Remove the target material to obtain a semi-finished target material with uneven zinc element distribution. The zinc content in this semi-finished target material gradually increases from top to bottom, with the lower surface being zinc-rich and the upper surface being zinc-deficient.

[0062] Step S5: Invert the first sintered target material so that the zinc-rich side faces up and place it into a high-temperature tube furnace. Start heating from room temperature at a rate of 3℃ / min to 10℃ / min, and hold at 700℃ for 30min to 90min. Then heat to 800℃ to 1300℃ at a rate of 3℃ / min to 8℃ / min and continue sintering at 800℃ to 1300℃ for 4 to 10 hours. Then cool down at a rate of 3℃ / min to 8℃ / min, and hold at 700℃ for 30min. Then cool down to room temperature at a rate of 3℃ / min to 8℃ / min. Remove the target material to obtain a zinc gallate target material with uniform composition and rich in zinc.

[0063] The present application will be further described below with reference to specific embodiments:

[0064] Example 1

[0065] The preparation of a zinc gallate target includes the following steps:

[0066] S1: Weigh zinc oxide powder and gallium oxide powder with a purity of 99.99% respectively, and mix them evenly to form a powder mixture (mixed powder). The proportion of zinc oxide powder in the powder mixture is 75 At%. Specifically, the amount of zinc oxide powder is 24.41g and the amount of gallium oxide powder is 18.74g. 43.15g of deionized water is poured into the powder mixture, and the mixture is ball-milled for 8 hours to form a slurry.

[0067] S2: Pour the slurry into a petri dish, place it in an oven, heat it at 90℃ for 4 hours, and grind the slurry into powder after drying.

[0068] S3: Pour the powder into the mold, then place it in the press and hold it under static pressure of 100MPa for 5 minutes to obtain the green blank, which has a relative density of 55%.

[0069] S4: Place the green blank into a high-temperature tube furnace and start heating from room temperature at a rate of 5℃ / min. After reaching 1000℃, hold for 30 minutes. Then, heat to 1450℃ at a rate of 5℃ / min and sinter at 1450℃ for 10 hours. Then, start cooling at a rate of 5℃ / min and hold for 30 minutes after reaching 1000℃. Then, cool to room temperature at a rate of 5℃ / min and remove the non-uniformly composed semi-finished target material.

[0070] S5: The semi-finished target material from the first sintering is inverted with the zinc-rich side facing up and placed into a high-temperature tube furnace. The temperature is increased from room temperature at a rate of 5℃ / min, and held at 1000℃ for 30 minutes. Then, the temperature is increased to 1250℃ at a rate of 5℃ / min and sintered at 1250℃ for 10 hours. Then, the temperature is decreased at a rate of 5℃ / min, and held at 1000℃ for 30 minutes. Then, the temperature is decreased to room temperature at a rate of 5℃ / min. The target material is then removed to obtain a zinc gallate target material with uniform zinc and gallium composition, wherein the atomic ratio of zinc to gallium in the target material is 3:2. Figure 2 These are photographs of the upper and lower surfaces of the target material in Example 1. Figure 3 This is a schematic diagram showing the locations of test points A, B, and C on the target material for the test components. Figure 4 The energy dispersive X-ray spectra at positions A, B, and C in this Example 1 are shown in Table 1. The atomic ratio of zinc to gallium at the three test positions is 3:2.

[0071] Table 1 shows the atomic ratios of zinc and gallium at test points A, B, and C in Example 1.

[0072] test points <![CDATA[At (Zn) %]]> <![CDATA[At (Ga) %]]> Zn / Ga A 60.03 39.97 3:2 B 60.05 39.95 3:2 C 59.98 40.02 3:2

[0073] Example 2

[0074] The preparation of a zinc gallate target includes the following steps:

[0075] S1: Weigh zinc oxide powder and gallium oxide powder with a purity of 99.99% respectively, and mix them evenly to form a powder mixture. The proportion of zinc oxide powder in the powder mixture is 66.67At%. Specifically, the amount of zinc oxide powder is 16.27g and the amount of gallium oxide powder is 18.74g. Add 35.01g of alcohol to the powder mixture and ball mill for 10 hours to form a slurry.

[0076] S2: Pour the slurry into a petri dish, place it in an oven, heat it at 90℃ for 6 hours, and grind the slurry into powder after drying.

[0077] S3: Pour the powder into the mold, then place it in the press and hold it under static pressure of 200MPa for 10 minutes to obtain the green blank with a relative density of 56%.

[0078] S4: Place the green blank into a high-temperature tube furnace and start heating from room temperature at a rate of 5℃ / min. After reaching 1000℃, hold for 30 minutes. Then, heat to 1400℃ at a rate of 5℃ / min and continue sintering at 1400℃ for 10 hours. Then, start cooling at a rate of 5℃ / min and hold for 30 minutes after reaching 1000℃. Then, cool to room temperature at a rate of 5℃ / min and remove the semi-finished target material with uneven composition.

[0079] S5: The semi-finished target material from the first sintering is inverted with the zinc-rich side facing up and placed into a high-temperature tube furnace. The temperature is increased from room temperature at a rate of 5°C / min, reaching 1000°C and held for 30 minutes. Then, the temperature is increased again at a rate of 5°C / min to 1300°C and sintered at 1300°C for 6 hours. Next, the temperature is decreased at a rate of 5°C / min, reaching 1000°C and held for 30 minutes. Finally, the temperature is decreased to room temperature at a rate of 5°C / min. The target material is then removed, yielding a zinc gallate target material with uniform zinc and gallium composition, wherein the atomic ratio of zinc to gallium in the target material is 1:1. According to... Figure 3 Sampling tests were conducted at the sampling test points A, B, and C shown, and the results are as follows: Figure 5 As shown in Table 2. Figure 5 The data are energy dispersive X-ray spectra at positions A, B, and C in this embodiment 2. The atomic ratio of zinc to gallium at the three test positions is 1:1.

[0080] Table 2 shows the atomic ratios of zinc and gallium at test locations A, B, and C in Example 2.

[0081] test points <![CDATA[At (Zn) %]]> <![CDATA[At (Ga) %]]> Zn / Ga A 50.08 49.93 1:1 B 50.05 49.95 1:1 C 49.96 50.04 1:1

[0082] Example 3

[0083] The preparation of a zinc gallate target includes the following steps:

[0084] S1: Weigh out zinc oxide powder and gallium oxide powder with a purity of 99.99% respectively, and mix them evenly to form a powder mixture. The proportion of zinc oxide powder in the powder mixture is 80 At%. Specifically, the amount of zinc oxide powder is 32.54g and the amount of gallium oxide powder is 18.74g. Add 35.01g of alcohol to the powder mixture and ball mill for 10 hours to form a slurry.

[0085] S2: Pour the slurry into a petri dish, place it in an oven, heat it at 90℃ for 6 hours, and grind the slurry into powder after drying.

[0086] S3: Pour the powder into the mold, then place it in the press and hold it under static pressure of 200MPa for 10 minutes to obtain the green blank with a relative density of 58%.

[0087] S4: Place the green blank into a high-temperature tube furnace and start heating from room temperature at a rate of 5℃ / min. After reaching 1000℃, hold for 30 minutes. Then, heat to 1400℃ at a rate of 5℃ / min and continue sintering at 1400℃ for 10 hours. Then, start cooling at a rate of 5℃ / min and hold for 30 minutes after reaching 1000℃. Then, cool to room temperature at a rate of 5℃ / min and remove the semi-finished target material with uneven composition.

[0088] S5: The semi-finished target material from the first sintering is inverted with the zinc-rich side facing up and placed into a high-temperature tube furnace. The temperature is increased from room temperature at a rate of 5°C / min, reaching 1000°C and held for 30 minutes. Then, the temperature is increased again at a rate of 5°C / min to 1300°C and sintered at 1300°C for 6 hours. Next, the temperature is decreased at a rate of 5°C / min, reaching 1000°C and held for 30 minutes. Finally, the temperature is decreased to room temperature at a rate of 5°C / min. The target material is then removed, yielding a zinc gallate target material with uniform zinc and gallium composition. Figure 3 Sampling was performed at test points A, B, and C, and energy dispersive X-ray spectra at positions A, B, and C were obtained. The atomic ratio of zinc to gallium at the three test positions in the target material was 2:1.

[0089] Example 4

[0090] The preparation of a zinc gallate target includes the following steps:

[0091] S1: Weigh zinc oxide powder and gallium oxide powder with a purity of 99.99% respectively, and mix them evenly to form a powder mixture. The proportion of zinc oxide powder in the powder mixture is 80 At%. Specifically, the amount of zinc oxide powder is 32.54g and the amount of gallium oxide powder is 18.74g. Add 35.01g of alcohol to the powder mixture and ball mill for 10 hours to form a slurry.

[0092] S2: Pour the slurry into a petri dish, place it in an oven, heat it at 150℃ for 2 hours, and grind the slurry into powder after drying.

[0093] S3: Pour the powder into the mold, then place it in the press and hold it under static pressure of 500MPa for 10 minutes to obtain a green blank with a relative density of 50%.

[0094] S4: Place the green blank into a high-temperature tube furnace, start heating from room temperature at a heating rate of 3℃ / min, hold at 1000℃ for 30min, then heat to 1250℃ at a heating rate of 8℃ / min, sinter at 1250℃ for 12h, then cool down at a cooling rate of 8℃ / min, hold at 1000℃ for 90min, then cool down to room temperature at a cooling rate of 8℃ / min, and remove the non-uniformly composed semi-finished target material.

[0095] S5: The semi-finished target material from the first sintering is inverted with the zinc-rich side facing up and placed into a high-temperature tube furnace. The temperature is increased from room temperature at a rate of 10°C / min, reaching 700°C and held for 90 min. Then, the temperature is increased to 800°C at a rate of 3°C / min and sintered at 800°C for 10 h. Next, the temperature is decreased at a rate of 3°C / min, reaching 700°C and held for 30 min. Finally, the temperature is decreased to room temperature at a rate of 3°C / min. The target material is then removed, yielding a zinc gallate target material with uniform zinc and gallium composition. Figure 3 Sampling was performed at test points A, B, and C, and energy dispersive X-ray spectra at positions A, B, and C were obtained. The atomic ratio of zinc to gallium at the three test positions in the target material was 2:1.

[0096] Example 5

[0097] The preparation of a zinc gallate target includes the following steps:

[0098] S1: Weigh zinc oxide powder and gallium oxide powder with a purity of 99.99% respectively, and mix them evenly to form a powder mixture (mixed powder). The proportion of zinc oxide powder in the powder mixture is 60 At%. Specifically, the amount of zinc oxide powder is 24.41g and the amount of gallium oxide powder is 10.61g. 35.02g of deionized water is poured into the powder mixture, and the mixture is ball-milled for 8 hours to form a slurry.

[0099] S2: Pour the slurry into a petri dish, place it in an oven, heat it at 90℃ for 4 hours, and grind the slurry into powder after drying.

[0100] S3: Pour the powder into the mold, then place it in the press and hold it under static pressure of 100MPa for 5 minutes to obtain the green blank, which has a relative density of 56%.

[0101] S4: Place the green blank into a high-temperature tube furnace, start heating from room temperature at a rate of 10℃ / min, hold at 1000℃ for 30min, then heat to 1650℃ at a rate of 5℃ / min, sinter at 1650℃ for 6h, then cool down at a rate of 5℃ / min, hold at 1000℃ for 30min, then cool down to room temperature at a rate of 5℃ / min, and remove the non-uniformly composed semi-finished target material.

[0102] S5: The semi-finished target material from the first sintering is inverted with the zinc-rich side facing up and placed into a high-temperature tube furnace. The temperature is increased from room temperature at a rate of 5°C / min, reaching 1000°C and held for 30 minutes. Then, the temperature is increased again at a rate of 8°C / min to 1300°C and sintered at 1300°C for 4 hours. Next, the temperature is decreased at a rate of 8°C / min, reaching 1000°C and held for 30 minutes. Finally, the temperature is decreased to room temperature at a rate of 8°C / min. The target material is then removed, yielding a zinc gallate target material with uniform zinc and gallium composition. Figure 3 Sampling was performed at test points A, B, and C, and energy dispersive X-ray spectra at positions A, B, and C were obtained. The atomic ratio of zinc to gallium at the three test positions in the target material was 3:4.

[0103] Comparative Example 1

[0104] S1: Weigh out zinc oxide powder and gallium oxide powder with a purity of 99.99% respectively, and mix them evenly to form a powder mixture. The proportion of zinc oxide powder in the powder mixture is 75 At%. Specifically, the amount of zinc oxide powder is 24.41 g and the amount of gallium oxide powder is 18.74 g. Add 43.15 g of deionized water to the powder mixture and ball mill for 8 hours to form a slurry.

[0105] S2: Pour the slurry into a petri dish, place it in an oven, and heat it at a constant temperature of 90℃ for 4 hours. After the slurry is dried, grind it into powder.

[0106] S3: Pour the powder into the mold, then place it in the press and hold it under static pressure of 100MPa for 5 minutes to obtain the green blank, which has a relative density of 55%.

[0107] S4: Place the green blank into a high-temperature tube furnace and start heating from room temperature at a rate of 5℃ / min. After reaching 1000℃, hold for 30 minutes. Then, heat to 1450℃ at a rate of 5℃ / min and sinter at 1450℃ for 10 hours. Then, start cooling at a rate of 5℃ / min and hold for 30 minutes after reaching 1000℃. Finally, heat to room temperature at a rate of 5℃ / min and remove the target material.

[0108] Target material 1 was prepared according to Comparative Example 1. Figure 3 Sampling tests were conducted at the sampling test points A, B, and C shown, and the results are as follows: Figure 6 As shown in Table 3. Figure 6 The energy-dispersive X-ray spectra at positions A, B, and C of Comparative Example 1 are shown. The atomic ratios of zinc and gallium at the three test positions are 4.67:1, 1.25:1, and 0.31:1, respectively.

[0109] The obtained target material has an uneven component distribution, which cannot meet the requirements for subsequent zinc gallate thin film preparation.

[0110] Table 3 shows the atomic ratios of zinc and gallium at test locations A, B, and C in Comparative Example 1.

[0111] test points <![CDATA[At (Zn) %]]> <![CDATA[At (Ga) %]]> Zn / Ga A 82.28 17.72 4.67:1 B 56.15 44.85 1.25:1 C 23.46 76.54 0.31:1

[0112] Comparative Example 2

[0113] S1: Weigh out zinc oxide powder and gallium oxide powder with a purity of 99.99% respectively, and mix them evenly to form a powder mixture. The proportion of zinc oxide powder in the powder mixture is 66.67 At%. Specifically, there are 16.27 g of zinc oxide powder and 18.74 g of gallium oxide powder. Add 35.01 g of alcohol to the powder mixture and ball mill for 10 hours to form a slurry.

[0114] S2: Pour the slurry into a petri dish, place it in an oven, and heat it at a constant temperature of 90℃ for 6 hours. After the slurry is dried, grind it into powder.

[0115] S3: Pour the powder into the mold, then place it in the press and hold it under static pressure of 200MPa for 10 minutes to obtain the green blank with a relative density of 56%.

[0116] S4: Place the green blank into a high-temperature tube furnace and start heating from room temperature at a rate of 5℃ / min. After reaching 1000℃, hold for 30 minutes. Then, heat to 1400℃ at a rate of 5℃ / min and sinter at 1400℃ for 10 hours. Then, start cooling at a rate of 5℃ / min and hold for 30 minutes after reaching 1000℃. Finally, heat to room temperature at a rate of 5℃ / min and remove the target material.

[0117] Target material 2 was prepared in Comparative Example 2. Figure 7 The images show the upper and lower surfaces of the target material in Comparative Example 2. The different colors of the upper and lower surfaces indicate that their compositions are also different.

[0118] The two components of the obtained target material are unevenly distributed, which cannot meet the requirements for subsequent zinc gallate thin film preparation.

[0119] Comparative Example 3

[0120] The preparation of Comparative Example 3 was largely the same as that of Comparative Example 1, except that the second sintering time was 11 hours.

[0121] Target material 3 was prepared in Comparative Example 3.

[0122] Figure 8 The image shows the target material in Comparative Example 3. The different colors at the edges and center indicate that its composition is not uniform. The obtained target material 3 has an uneven composition distribution, which cannot meet the requirements for subsequent zinc gallate film preparation.

[0123] Comparative Example 4

[0124] The preparation of Comparative Example 4 was largely the same as that of Comparative Example 1, except that the second sintering time was 3 hours.

[0125] Target material 4 was prepared in Comparative Example 4.

[0126] Because the second sintering time was too short, the concentration gradient was not fully compensated, and the colors of the upper and lower surfaces of the target material 4 were different, indicating that their compositions were also different.

[0127] The obtained target material has an uneven distribution of four components, which cannot meet the requirements for subsequent zinc gallate thin film preparation.

[0128] Comparative Example 5

[0129] The preparation of Comparative Example 5 was largely the same as that of Comparative Example 1, except that during the second sintering, the temperature was increased to the second sintering temperature at a rate of 9℃ / min.

[0130] Target material 5 was prepared in Comparative Example 5.

[0131] The different colors of the upper and lower surfaces of target material 5 indicate that their compositions are also different.

[0132] The obtained target material has an uneven distribution of five components, which cannot meet the requirements for subsequent zinc gallate thin film preparation.

[0133] Because the heating rate was too fast during the second sintering, the composition gradient was not compensated, and the color of the upper and lower surfaces of the target was still uneven. The five components of the obtained target were not evenly distributed, which could not meet the requirements for subsequent zinc gallate film preparation.

[0134] Comparative Example 6

[0135] The preparation of Comparative Example 6 is largely the same as that of Comparative Example 1, except that during the second sintering, the temperature was increased to the second sintering temperature at a rate of 2℃ / min.

[0136] Target material 6 was prepared in Comparative Example 6.

[0137] The different colors of the upper and lower surfaces of the target material 6 indicate that its composition is also different.

[0138] The obtained target material has an uneven distribution of six components, which cannot meet the requirements for subsequent zinc gallate thin film preparation.

[0139] It should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0140] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method for preparing a zinc gallate target, characterized in that: include, Step 1): Zinc oxide powder and gallium oxide powder are mixed to obtain a mixed powder. The mixed powder is then mixed with a solvent and ball-milled to obtain a slurry. Step 2): Dry the slurry and then grind it into powder; Step 3): Press the powder into a raw blank; Step 4): The green blank is sintered for the first time to obtain a semi-finished target material, wherein the first sintering temperature is 1250~1650℃; Step 5): The semi-finished target material obtained in Step 4) is inverted and then sintered a second time to obtain the zinc gallate target material, wherein the second sintering temperature is 800~1300℃ and the second sintering temperature is lower than the first sintering temperature; The second sintering time is 4-10 hours, the first sintering time is 6-12 hours, and the first sintering time is greater than or equal to the second sintering time.

2. The preparation method according to claim 1, characterized in that: In step 5), the temperature is increased to the second sintering temperature at a heating rate of 3~8℃ / min.

3. The preparation method according to claim 1, characterized in that: In step 5), a first heat preservation is performed before the second sintering. The first heat preservation temperature is 700~1000℃, and the first heat preservation temperature is less than or equal to the second sintering temperature.

4. The preparation method according to claim 3, characterized in that: In step 5), the temperature is increased from room temperature to the first holding temperature at a heating rate of 3~10℃ / min, and the holding time is 30~90min; then the temperature is increased to the second sintering temperature at a heating rate of 3~8℃ / min, and sintering is continued for 4~10h; then the temperature is decreased to the second holding temperature at a cooling rate of 3~8℃ / min, the second holding temperature is 700℃~1000℃ and the second holding temperature is lower than the second sintering temperature, and the temperature is held for 30min; finally, the temperature is decreased to room temperature at a cooling rate of 3~8℃ / min.

5. The preparation method according to any one of claims 1-4, characterized in that: In step 1), zinc oxide powder and gallium oxide powder are weighed according to a mass ratio of zinc oxide to gallium oxide of 3:7 to 7:3, and then the two are mixed to obtain a mixed powder. The mixed powder is added to a solvent and then ball-milled for 6 to 10 hours to obtain a grinding slurry.

6. The preparation method according to claim 5, characterized in that: In step 1), the mass ratio of the solvent to the mixed powder is 1:2 to 2:1; The solvent is alcohol or deionized water.

7. The preparation method according to any one of claims 1-4, characterized in that: In step 2), the drying process involves heating at a constant temperature of 80-150°C for 2-6 hours.

8. The preparation method according to any one of claims 1-4, characterized in that: In step 3), the green blank is cold isostatically pressed at a pressure of 100~500Mpa for 5~10min to obtain the green blank. The relative density of the green blank is 50%~62%.

9. The preparation method according to claim 1, characterized in that: In step 4), the temperature is increased to the first sintering temperature at a heating rate of 3~8℃ / min.

10. The preparation method according to claim 9, characterized in that: In step 4), the green blank is placed in a high-temperature tube furnace, and the temperature is increased from room temperature to 1000°C at a heating rate of 3~10°C / min, and held for 30~90min. Then the temperature is increased to the first sintering temperature at a heating rate of 3~8°C / min, and sintering is continued for 6~12h. Then the temperature is decreased to 1000°C at a cooling rate of 3~8°C / min and held for 30~90min. Finally, the temperature is decreased to room temperature at a cooling rate of 3~8°C / min.

11. A zinc gallate target, characterized in that: It is prepared by the preparation method described in any one of claims 1-10.

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