Zinc-tellurium alloy target material and preparation method thereof

Abstract

The invention discloses a zinc tellurium alloy target material and a preparation method thereof, relates to the field of semiconductor target material preparation, and aims to solve the problem of how to prepare a zinc telluride target material with uniform particle size, and the technical scheme is as follows: 1) selecting a Zn ingot with the purity of 99.99% and a Te ingot with the purity of 99.99% as raw materials for proportioning; (2) weighing and proportioning the Zn ingot and the Te ingot, and then adding the Zn ingot and the Te ingot into a vacuum smelting furnace for mixed smelting to obtain a blank; (3) the pretreated blank is added into gas atomization granulation equipment for granulation; (4) powder particles obtained through gas atomization granulation are put into a ball milling tank to be subjected to ball milling, and powder is obtained; the invention discloses a zinc tellurium alloy target material and a preparation method thereof.The zinc tellurium alloy target material and the preparation method thereof have the advantages that the zinc tellurium alloy target material is low in gas content, uniform in microstructure and fine in grain size.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor target material preparation, and more specifically, to a zinc-tellurium alloy target material and a preparation method thereof. Background Art

[0002] Zinc telluride is a II-VI group compound with wide bandgap characteristics. It is a P-type wide bandgap semiconductor with a bandgap width of about 2.26eV at room temperature. Its crystal structure is similar to that of brass, with hexagonal and cubic crystal forms. It has good electro-optical effect under the action of near-infrared ultrashort pulses, and is a commonly used optical rectification THz radiation source and detection material. It is also used in optoelectronic devices such as green light emitting devices, solar cells, waveguides and modulators.

[0003] At present, the commonly used method for preparing zinc telluride targets is dry / wet alloy preparation - (cold pressing) - hot pressing sintering - machining: the powder before hot pressing sintering has problems such as uneven particle size and irregular shape, which leads to deviations in the density and microstructure uniformity of the sintered product, and then leads to poor quality of the final target. There are few descriptions of the ZnTe powder granulation process in the current market. Currently, mechanical crushing is commonly used for granulation. This method is prone to problems such as uneven particle size distribution, insufficient particle strength, and difficulty in controlling particle size distribution, which makes it difficult to control the quality of the target after subsequent sintering. Therefore, ensuring that the ZnTe powder particles are uniform in size and regular in shape is a major problem in the current production of zinc telluride targets.

[0004] Therefore, a new solution needs to be proposed to solve this problem. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a zinc-tellurium alloy target material and a preparation method thereof. The tellurium-zinc alloy target material is formed by vacuum melting + vacuum induction atomization granulation + vacuum hot pressing. The process is controllable, the stability is high, and the cost is low. The obtained product has high purity, high density, low gas content, uniform microstructure, fine grain size, and is suitable for mass production.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: A method for preparing a zinc-tellurium alloy target comprises the following steps: 1) Select Zn ingots with a purity of 99.99% and Te ingots with a purity of 99.99% as raw materials, and mix them according to the atomic ratio of Zn:Te=1.02-1.05:1; 2) Weighing and proportioning the Zn ingot and the Te ingot, and then adding them into a vacuum melting furnace for mixed melting to obtain a blank; 3) Adding the pretreated blank into the aerosol granulation equipment for granulation; 4) The powder particles obtained by aerosol granulation are put into a ball mill and ball milled to obtain powder; 5) The density of the ball-milled powder is converted and weighed according to the product specifications, and the powder is placed in a graphite mold and placed in a vacuum sintering furnace for sintering; 6) Perform various machining operations on the sintered products to the required shape and size.

[0007] The present invention is further configured as follows: in step 2), the smelting parameters are: temperature 450-600°C, heating rate 20-50°C / min, vacuum degree <10 -2 Pa, smelting time 0.5-2h.

[0008] The present invention is further configured as follows: the selected smelting equipment is a vacuum smelting furnace.

[0009] The present invention is further configured as follows: in step 3), the granulation parameters are: spray pressure 2-8MPa, cooling water inlet temperature <30°C, atomizing gas temperature 40-60°C, nozzle diameter 2-6mm, atomizing medium N2 or Ar gas, smelting chamber temperature 900-1200°C, and guide tube insulation temperature 800-1000°C.

[0010] The present invention is further configured as follows: in step 4), the ball milling parameters are: ball-to-material ratio of silicon nitride balls as ball milling medium is 3:1, the rotation speed is 50-70 r / min, and the time is 10-15 h.

[0011] The present invention is further configured as follows: in step 5), the sintering parameters are: sintering temperature 700-1000°C, heating rate 1-5°C / min, holding time 2-4h, vacuum degree <10 -2 Pa, sintering pressure 15-25MPa.

[0012] The present invention is further configured as follows: in step 5), a lubricant is required to lubricate the mold during the sintering process.

[0013] The present invention is further configured as follows: the lubricant is talcum powder, cubic boron nitride powder, and carbon black.

[0014] The present invention also provides a zinc-tellurium alloy target material, which is prepared by the above preparation process.

[0015] In summary, the present invention has the following beneficial effects: 1. The ZnTe alloy is prepared by vacuum melting. Compared with the ZnTe material prepared by the traditional manufacturing process, the ZnTe alloy prepared by the present invention has small grains, fine and uniformly distributed precipitated phases, and the chemical composition and organization of the product are effectively controlled at the macro and micro levels, so the mechanical properties of the product can be kept isotropic, and the overall performance is significantly improved; 2. The ZnTe powder particles are prepared by vacuum induction atomization granulation: Compared with the traditional granulation method, the ZnTe particles prepared by the present invention have the advantages of excellent particle sphericity, uniform particle size distribution, good fluidity and low cost, which ensures the uniform organization and composition of the final product; 3. The granulated powder is further processed by ball milling, which enhances the uniformity of particle distribution, appropriately reduces the particle size, and increases the particle surface energy, which is more conducive to sintering and fusion; 4. Vacuum hot pressing sintering is used to form a rough blank of powder and further densify it, eliminating closed pores inside the product, exhausting gas, and further refining the grains of the product and eliminating abnormally grown grains; in addition, the grain arrangement can be made consistent on a macro scale, thereby improving the mechanical properties of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is the phase diagram of ZnTe binary alloy; Figure 2 This is the SEM microstructure morphology of Example 1; Figure 3 This is the SEM microstructure morphology of Comparative Example 3. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0018] The invention provides a tellurium zinc alloy target material produced by vacuum melting+vacuum induction gas atomization granulation+vacuum hot pressing and a preparation method thereof.

[0019] 1) Select Zn ingots with a purity of 99.99% and Te ingots with a purity of 99.99% as raw materials, and mix them according to the atomic ratio of Zn:Te=1.02~1.05:1 (calculated by the Clausius formula, the vapor pressure of zinc is higher than that of tellurium, so the proportion of zinc needs to be slightly increased to obtain a 1:1 ZnTe alloy).

[0020] 2) Weigh and mix the Zn ingot and Te ingot in a certain ratio, then add them into the vacuum melting furnace for melting, and mix the two metal solutions by stirring; melting parameters: temperature 450-600℃, heating rate 20-50℃ / min, vacuum degree <10 -2 Pa, smelting time 0.5-2h.

[0021] The selected smelting equipment is a vacuum smelting furnace. The purposes of using a vacuum smelting furnace are: 1) to reduce the gas content of the product, especially the O content; 2) to eliminate the need for slag removal, thereby reducing material waste; and 3) to reduce the introduction of impurities.

[0022] 3) Add the pretreated blank into the gas atomization granulation equipment for granulation. The granulation parameters are as follows: spray pressure 2-8MPa, cooling water inlet temperature <30℃, atomizing gas temperature 40-60℃, nozzle diameter 2-6mm, atomizing medium N2 or Ar gas, melting chamber temperature 900-1200℃, and guide tube insulation temperature 800-1000℃.

[0023] 4) The powder particles obtained by aerosol granulation are put into a ball mill for ball milling to refine the particle size and optimize the particle size distribution. The ball milling parameters are as follows: ball-to-material ratio of silicon nitride ball 3:1, rotation speed 50-70r / min, and time 10-15h.

[0024] 5) After ball milling, the density of the powder is converted and weighed according to the product specifications. The powder is placed in a graphite mold and sintered in a vacuum sintering furnace. The sintering parameters are: sintering temperature 700-1000℃, heating rate 1-5℃ / min, holding time 2-4h, vacuum degree <10 -2 Pa, sintering pressure 15-25MPa. During the sintering process, lubricants are needed to lubricate the mold to reduce the friction between the product and the mold, avoid the risk of mold sticking, product cracking and damage to the mold. The lubricant is a substance with high hardness or self-lubricating properties such as talcum powder, cubic boron nitride powder, and carbon black.

[0025] 6) Perform various machining operations on the extruded products to the required shape and size.

[0026] The tellurium zinc alloy target was prepared by this process, and its alloy phase diagram is shown in the attached figure. Figure 1 shown.

[0027] The following is a detailed description: Embodiment 1: Add Zn and Te ingots with an atomic ratio of Zn:Te=1.02:1 into a vacuum melting furnace and first evacuate to 10 - 2 Pa, heat up to 500℃ at a heating rate of 30℃ / min, start the stirring device after the metal ingot is completely melted to form an alloy solution, electromagnetically stir for 2h, fully mix the two metal liquids, open the discharge port below the vacuum melting furnace, introduce the solution into the powder collector, and pre-treat the blank after cooling to remove surface particles adhering to it.

[0028] The pretreated ZnTe blank was placed in a gas atomization melting chamber, the melting chamber temperature was set at 1000°C, the guide tube insulation temperature was set at 900°C, the gas atomization granulation nozzle size was selected to be 2mm, the atmosphere was N2, and the gas pressure was 6MPa, and a gas atomization granulation was performed.

[0029] The granulated ZnTe powder was loaded into a silicon nitride ball mill, and silicon nitride balls were selected as the ball milling medium, with a ball-to-material ratio of 3:1, a total loading of 1 / 2, a rotation speed of 60 r / min, and a ball milling time of 12 h. After ball milling, the powder was sieved with an 80-mesh screen.

[0030] The ball-milled powder is weighed and loaded into a graphite mold. After the lubricant is sprayed on the graphite surface, it is placed in a vacuum hot-pressing sintering furnace. First, the vacuum is drawn to 10 -2 Pa, heat to 500℃ at a heating rate of 2℃ / min and keep warm for 1h; heat to 800℃ at a heating rate of 1℃ / min, set the sintering pressure to 20MPa, keep warm for 4h and then cool down with the furnace. After the temperature drops to room temperature, take out the product and carry out appropriate machining to the required shape and size.

[0031] The SEM microstructure morphology of the prepared tellurium zinc alloy target is shown in the attached figure. Figure 2 As shown, the microstructure is uniform and the grain size is fine.

[0032] Embodiment 2: Add Zn and Te ingots with an atomic ratio of Zn:Te=1.02:1 into a vacuum melting furnace and first evacuate to 10 - 2 Pa, heat up to 500℃ at a heating rate of 30℃ / min, start the stirring device after the metal ingot is completely melted to form an alloy solution, electromagnetically stir for 2h, fully mix the two metal liquids, open the discharge port below the vacuum melting furnace, introduce the solution into the powder collector, and pre-treat the blank after cooling to remove surface particles adhering to it.

[0033] The pretreated ZnTe blank was placed in a gas atomization melting chamber, the melting chamber temperature was set at 1000°C, the guide tube insulation temperature was set at 900°C, the gas atomization granulation nozzle size was selected to be 4mm, the atmosphere was N2, and the gas pressure was 8MPa, and a gas atomization granulation was performed.

[0034] The granulated ZnTe powder was loaded into a silicon nitride ball mill, and silicon nitride balls were selected as the ball milling medium, with a ball-to-material ratio of 3:1, a total loading of 1 / 2, a rotation speed of 60 r / min, and a ball milling time of 12 h. After ball milling, the powder was sieved with an 80-mesh screen.

[0035] The ball-milled powder is weighed and loaded into a graphite mold. After the lubricant is sprayed on the graphite surface, it is placed in a vacuum hot-pressing sintering furnace. First, the vacuum is drawn to 10 -2 Pa, heat to 500℃ at a heating rate of 2℃ / min and keep warm for 1h; heat to 800℃ at a heating rate of 1℃ / min, set the sintering pressure to 20MPa, keep warm for 3h and then cool down with the furnace. After the temperature drops to room temperature, take out the product and perform appropriate machining to the required shape and size.

[0036] Embodiment 3: Add Zn and Te ingots with an atomic ratio of Zn:Te=1.05:1 into a vacuum melting furnace and first evacuate to 10 - 2 Pa, heat up to 500℃ at a heating rate of 30℃ / min, start the stirring device after the metal ingot is completely melted to form an alloy solution, electromagnetically stir for 2h, fully mix the two metal liquids, open the discharge port below the vacuum melting furnace, introduce the solution into the powder collector, and pre-treat the blank after cooling to remove surface particles adhering to it.

[0037] The pretreated ZnTe blank was placed in a gas atomization melting chamber, the melting chamber temperature was set at 1000°C, the guide tube insulation temperature was set at 900°C, the gas atomization granulation nozzle size was selected to be 2mm, the atmosphere was N2, and the gas pressure was 6MPa, and a gas atomization granulation was performed.

[0038] The granulated ZnTe powder was loaded into a silicon nitride ball mill, and silicon nitride balls were selected as the ball milling medium, with a ball-to-material ratio of 3:1, a total loading of 1 / 2, a rotation speed of 60 r / min, and a ball milling time of 12 h. After ball milling, the powder was sieved with an 80-mesh screen.

[0039] The ball-milled powder is weighed and loaded into a graphite mold. After the lubricant is sprayed on the graphite surface, it is placed in a vacuum hot-pressing sintering furnace. First, the vacuum is drawn to 10 -2 Pa, heat to 500℃ at a heating rate of 2℃ / min and keep warm for 1h; heat to 800℃ at a heating rate of 1℃ / min, set the sintering pressure to 20MPa, keep warm for 4h and then cool down with the furnace. After the temperature drops to room temperature, take out the product and carry out appropriate machining to the required shape and size.

[0040] Comparative Example 1 ZnTe alloy targets were prepared by melt casting from Zn ingots and Te ingots with an atomic ratio of Zn:Te=1:1. First, the Te ingot was heated to 500°C in a medium frequency melting furnace to form a tellurium melt, and then the Zn ingot was gradually added to the molten Te solution and stirred for about 30 minutes. The evenly stirred molten liquid was cast into a mold, and the blank was taken out after cooling to room temperature and machined to the required size.

[0041] Comparative Example 2 Weigh Zn and Te ingots with an atomic ratio of Zn:Te=1:1 and add them into a tungsten steel tank, and add 1% stearic acid as a process control agent. The ball milling parameters are: ball-to-material ratio 3:1, total loading 1 / 2, ball milling time 9h, vacuum the tank to a vacuum degree of 150Pa, ball milling speed of 500 / 700r / min alternating speed per minute, and the powder after ball milling is sieved with an 80-mesh screen.

[0042] After calculating the required weight of the sieved powder according to the product size, put it into the hot-pressed graphite mold. When filling the mold, first pad graphite paper on the bottom and around the inside, and add the powder into the graphite mold cavity in batches. Each time a layer is added, the powder must be leveled, and then graphite paper is padded. The graphite mold and graphite paper must be evenly sprayed with high-temperature resistant mold agent.

[0043] Place the graphite mold directly under the pressure head of the vacuum hot press furnace, pre-press the mold with 2MPa, and set the sintering parameters. First, evacuate the furnace to 10 -2 Pa, first heat to 120℃ at 2℃ / min and keep it for 2h; then heat to 350℃ at 2℃ / min and keep it for 3h; then heat to 800℃ at 4℃ / min, pressurize to 20MPa at 1MPa / min during the heating process, keep it for 2h, then cool down and release the pressure with the furnace. After the temperature drops to room temperature, open the furnace, take out the mold for demoulding, and machine the ZnTe alloy to the required size.

[0044] Comparative Example 3 Weigh Zn and Te ingots with an atomic ratio of Zn:Te=1:1 and add them into a tungsten steel tank, and add 1% stearic acid as a process control agent. The ball milling parameters are: ball-to-material ratio 3:1, total loading 1 / 2, ball milling time 9h, vacuum the tank to a vacuum degree of 150Pa, ball milling speed of 500 / 700r / min alternating speed per minute, and the powder after ball milling is sieved with an 80-mesh screen.

[0045] The mixed powder was cold pressed at a pressure of 200 MPa and a holding time of 3 min. The pressed green blank was vacuum sintered. The vacuum was first drawn to 10 -2 Pa, heat up to 120℃ at a heating rate of 2℃ / min and keep warm for 1h, heat up to 550℃ at 2℃ / min and keep warm for 1h; heat up to 800℃ at a heating rate of 1℃ / min, keep warm for 4h, then cool down with the furnace, take out the product for machining after the temperature drops to room temperature.

[0046] The SEM microstructure morphology of the prepared tellurium zinc alloy target is shown in the attached figure. Figure 3 As shown, the microstructure is relatively uneven and the grain size is relatively coarse.

[0047] The above-mentioned Examples 1-3 and Comparative Examples 1-3 were tested and the results were shown in Table 1.

[0048] Table 1: Test results Density / % Average grain size / μm Segregation percentage / % Oxygen content / PPM Example 1 99.9 38 ≤2 ≤200 Example 2 99.8 75 ≤2 ≤200 Example 3 99.9 46 ≤2 ≤200 Comparative Example 1 93.2 163 ≥5 ≥1000 Comparative Example 2 92.3 180 ≤5 ≤500 Comparative Example 3 96.5 124 ≤2 ≤800 The detection methods of density, average grain size, segregation percentage and oxygen content in Table 1 above are shown in Table 2 Table 2: Testing instruments or methods Detection items Detection Methods Density Density tester (buoyancy method) Average grain size XRD Segregation percentage XRF selection Oxygen content Oxygen content detector In summary, the present invention adopts vacuum melting to prepare ZnTe alloy; compared with ZnTe materials prepared by traditional manufacturing processes, the ZnTe alloy prepared by the present invention has small grains, fine and uniformly distributed precipitated phases, and the chemical composition and organization of the product are effectively controlled at the macro and micro levels, so that the mechanical properties of the product can be kept isotropic, and the overall performance is significantly improved; the ZnTe powder particles are prepared by vacuum induction atomization granulation: compared with the traditional granulation method, the ZnTe particles prepared by the present invention have the advantages of excellent particle sphericity, uniform particle size distribution, good fluidity, and low cost, which ensures the uniform organization of the final product; the granulated powder is further processed by ball milling, the uniformity of particle distribution is enhanced, the particle size of the particles is appropriately reduced, and the particle surface energy is increased, which is more conducive to sintering and fusion; vacuum hot pressing sintering is adopted to form a rough embryo of the powder and further densify it, eliminate the closed pores inside the product, discharge gas, and further refine the grains of the product and eliminate abnormally grown grains; in addition, the grain arrangement can be made consistent at a macro level, and the mechanical properties of the product are improved.

[0049] The tellurium zinc alloy target material prepared by the present invention has controllable process, high stability and low cost; the obtained product has high purity, high density, low gas content, uniform microstructure and fine grain size, and is suitable for mass production.

[0050] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a zinc-tellurium alloy target, It is characterized in that The following steps are involved: 1) Select Zn ingots with a purity of 99.99% and Te ingots with a purity of 99.99% as raw materials, and mix them according to the atomic ratio of Zn:Te=1.02-1.05:1; 2) Weighing and proportioning the Zn ingot and the Te ingot, and then adding them into a vacuum melting furnace for mixed melting to obtain a blank; 3) Adding the pretreated blank into the aerosol granulation equipment for granulation; 4) The powder particles obtained by aerosol granulation are put into a ball mill and ball milled to obtain powder; 5) The density of the ball-milled powder is converted and weighed according to the product specifications, and the powder is placed in a graphite mold and placed in a vacuum sintering furnace for sintering; 6) Perform various machining operations on the sintered products to the required shape and size.

2. A method for preparing a zinc-tellurium alloy target according to claim 1, Features: In step 2), the melting parameters are: temperature 450-600℃, heating rate 20-50℃ / min, vacuum degree <10 -2 Pa, smelting time 0.5-2h.

3. A method for preparing a zinc-tellurium alloy target according to claim 2, Features: The selected smelting equipment is a vacuum melting furnace.

4. The method for preparing a zinc-tellurium alloy target according to claim 1, Features: In step 3), the granulation parameters are: spray pressure 2-8MPa, cooling water inlet temperature <30℃, atomizing gas temperature 40-60℃, nozzle diameter 2-6mm, atomizing medium N 2 Or Ar gas, melting chamber temperature 900-1200℃, guide tube insulation temperature 800-1000℃.

5. The method for preparing a zinc-tellurium alloy target according to claim 1, Features: In step 4), the ball milling parameters are as follows: ball milling medium silicon nitride ball to material ratio 3:1, rotation speed 50-70 r / min, time 10-15 h.

6. The method for preparing a zinc-tellurium alloy target according to claim 1, Features: In step 5), the sintering parameters are: sintering temperature 700-1000℃, heating rate 1-5℃ / min, holding time 2-4h, vacuum degree <10 -2 Pa, sintering pressure 15-25MPa.

7. A method for preparing a zinc-tellurium alloy target according to claim 6, Features: In step 5), a lubricant is required to lubricate the mold during the sintering process.

8. A method for preparing a zinc-tellurium alloy target according to claim 7, Features: The lubricant is talcum powder, cubic boron nitride powder and carbon black.

9. A zinc-tellurium alloy target, Features: Prepared by the preparation method according to any one of claims 1 to 8.

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