A method for preparing a phase change memory material titanium-antimony-tellurium target

Abstract

The application provides a preparation method of a phase change storage material titanium-antimony-tellurium target material, and belongs to the field of microelectronic technology. The application adopts a segmented heat treatment process of high first and low later, ensures that titanium and antimony and titanium and tellurium are synthesized into titanium antimonide and titanium telluride respectively, and titanium antimonide and titanium telluride have better compatibility compared with metal titanium and antimony telluride, long time insulation during synthesis ensures complete reaction, titanium can be uniformly distributed in the grain boundary of antimony telluride after the target material is prepared, and then low-temperature vacuum hot-pressing sintering is adopted to prevent target material grain growth caused by high temperature, and long time pressure keeping is adopted to ensure that the phase is more uniform, the phase change storage material titanium-antimony-tellurium target material with high purity, low oxygen content and relative density greater than or equal to 95% is obtained, the quality index is better, and therefore the thin film deposition efficiency and performance can be improved.

Description

Technical Field

[0001] This invention relates to the field of microelectronics technology, and in particular to a method for preparing a titanium-antimony-tellurium target for phase change memory materials. Background Technology

[0002] Titanium-antimony-tellurium (TIT-T) phase change materials are a new generation of phase change memory materials. Compared with traditional germanium-antimony-tellurium (Ge2Sb2Te5) phase change memory materials, they have advantages such as fast phase change rate, high crystallization temperature, good thermal stability, and strong data retention. In the preparation of TTI-antimony-tellurium phase change memory thin films, magnetron sputtering of TTI-antimony-tellurium targets provides a clean environment and allows for controllable composition, film thickness, and crystal orientation, making it a relatively ideal method for thin film preparation. However, the current production technology for TTI-antimony-tellurium phase change memory targets, which serve as the material source for magnetron sputtering, is still under development. There are areas for improvement. Current production methods primarily employ a hot-pressing and sintering process involving a mixture of titanium powder and antimony telluride powder. Due to the large specific surface area and long aging time of titanium powder, its high oxygen content results in titanium-antimony-telluride targets with oxygen levels exceeding 1000 ppm. Furthermore, metallic titanium and antimony telluride are incompatible, leading to agglomeration during hot-pressing and sintering. This agglomeration prevents uniform distribution within the antimony telluride grain boundaries, causing quality issues such as uneven composition, surface color variations, and poor mechanical properties, thus affecting the quality and storage performance of titanium-antimony-telluride phase change memory films. Therefore, providing a method for preparing high-purity, low-oxygen-content, and high-density titanium-antimony-telluride phase change memory targets has become a pressing technical problem in this field. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a titanium-antimony-tellurium target for phase change memory. The titanium-antimony-tellurium target for phase change memory prepared by the method of this invention has a purity of ≥99.95%, an oxygen content of ≤1000ppm, and a good relative density, which can improve thin film deposition efficiency and data retention.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a titanium-antimony-tellurium target for phase change memory materials, comprising the following steps: (1) Titanium particles, antimony particles and tellurium particles are mixed to obtain mixed particles, and then the mixed particles are sintered to obtain titanium-antimony-tellurium alloy blocks; (2) The titanium-antimony-tellurium alloy block obtained in step (1) is crushed to obtain alloy powder; (3) The alloy powder obtained in step (2) is subjected to low-temperature vacuum hot pressing sintering to obtain a phase change memory material titanium-antimony-tellurium target; The sintering method in step (1) is as follows: control the vacuum degree of sintering to ≤1Pa, first heat up to 690~800℃ at a heating rate of 2~10℃ / min, hold for 3~4h, then heat up to 1000~1200℃ at a heating rate of 5~15℃ / min, hold for 10~12h, then cool down to 950~1050℃ at a cooling rate of 1~3℃ / min, hold for 4~8h, and finally cool down to room temperature with the furnace. In step (3), the holding temperature of low-temperature vacuum hot pressing sintering is 500~650℃, the vacuum degree of low-temperature vacuum hot pressing sintering is ≤1Pa, the pressure of low-temperature vacuum hot pressing sintering is 20~50MPa, and the holding time of low-temperature vacuum hot pressing sintering is 2~3h.

[0005] Preferably, the particle size of the titanium particles, antimony particles and tellurium particles in step (1) is 1~10 mm.

[0006] Preferably, the purity of the titanium particles, antimony particles and tellurium particles in step (1) is independently ≥99.99%.

[0007] Preferably, in step (1), the antimony particles are formed by crushing high-purity antimony blocks, and the tellurium particles are formed by crushing high-purity tellurium blocks.

[0008] Preferably, the molar ratio of titanium particles, antimony particles and tellurium particles in step (1) is (0.2~0.4):(1~3):(2~4).

[0009] Preferably, the molar ratio of the titanium particles, antimony particles, and tellurium particles is 0.3:2:3.

[0010] Preferably, in step (2), the crushing method is to first crush the material into small pieces by physical crushing, then put it into a vacuum ball mill for ball milling, and finally sieve it.

[0011] Preferably, the grinding balls used in the ball mill are zirconia balls with a diameter of 5 mm, the vacuum degree of the ball mill is ≤0.5 Pa, the rotation speed of the ball mill is 300~350 rpm, and the ball milling time is 4~6 h.

[0012] Preferably, the particle size of the alloy powder in step (2) is 150~300 mesh.

[0013] Preferably, in step (3), the molar ratio of titanium, antimony and tellurium in the phase change storage material titanium-antimony-tellurium target is (0.2~0.4):(1~3):(2~4).

[0014] This invention provides a method for preparing a titanium-antimony-tellurium target for phase change memory, comprising the following steps: mixing titanium particles, antimony particles, and tellurium particles to obtain mixed particles; sintering the mixed particles to obtain a titanium-antimony-tellurium alloy block; pulverizing the titanium-antimony-tellurium alloy block to obtain alloy powder; and subjecting the alloy powder to low-temperature vacuum hot pressing sintering to obtain the titanium-antimony-tellurium target for phase change memory. The sintering method is as follows: controlling the vacuum degree of sintering to ≤1 Pa, and first heating to 690~800 °C at a heating rate of 2~10 °C / min. The temperature is increased to 1000-1200℃ at a rate of 5-15℃ / min and held for 10-12 hours. Then, the temperature is decreased to 950-1050℃ at a rate of 1-3℃ / min and held for 4-8 hours. Finally, the temperature is cooled to room temperature in the furnace. The holding temperature of the low-temperature vacuum hot pressing sintering is 500-650℃, the vacuum degree of the low-temperature vacuum hot pressing sintering is ≤1Pa, the pressure of the low-temperature vacuum hot pressing sintering is 20-50MPa, and the holding time of the low-temperature vacuum hot pressing sintering is 2-3 hours. The preparation method provided by this invention employs a segmented heat treatment process, first high and then low, to ensure that titanium and antimony, and titanium and tellurium, are first synthesized into titanium antimonide and titanium telluride respectively. Titanium antimonide and titanium telluride exhibit better compatibility than metallic titanium and antimony telluride. Prolonged heat treatment during synthesis ensures complete reaction, resulting in uniform titanium distribution within the grain boundaries of antimony telluride after target material preparation. Furthermore, low-temperature vacuum hot pressing sintering prevents high-temperature grain growth in the target material, and prolonged pressure holding ensures more uniform phase composition. This yields a high-purity, low-oxygen-content titanium-antimony-tellurium target for phase change memory, with a relative density ≥95%, resulting in superior quality indicators and improved thin film deposition efficiency and performance. The preparation method provided by this invention has a simple production process and reduces production costs. Results from the examples show that the titanium-antimony-tellurium target for phase change memory prepared by the method provided by this invention has a relative density RD ≥95%, purity ≥99.95%, and oxygen content ≤1000ppm, which can improve thin film deposition efficiency and performance. Detailed Implementation

[0015] This invention provides a method for preparing a titanium-antimony-tellurium target for phase change memory materials, comprising the following steps: (1) Titanium particles, antimony particles and tellurium particles are mixed to obtain mixed particles, and then the mixed particles are sintered to obtain titanium-antimony-tellurium alloy blocks; (2) The titanium-antimony-tellurium alloy block obtained in step (1) is crushed to obtain alloy powder; (3) The alloy powder obtained in step (2) is subjected to low-temperature vacuum hot pressing sintering to obtain a phase change memory material titanium-antimony-tellurium target.

[0016] This invention mixes titanium particles, antimony particles, and tellurium particles to obtain mixed particles, and then sintersects the mixed particles to obtain a titanium-antimony-tellurium alloy block.

[0017] In this invention, the purity of the titanium particles, antimony particles, and tellurium particles is preferably ≥99.99% independently; the antimony particles are preferably formed by crushing high-purity antimony blocks; the tellurium particles are preferably formed by crushing high-purity tellurium blocks; and the purity of the high-purity antimony blocks and high-purity tellurium blocks is preferably ≥99.99% independently. This invention does not have a specific limitation on the specific source of the titanium particles, high-purity antimony blocks, and high-purity tellurium blocks; commercially available products well-known to those skilled in the art can be used. This invention does not have a specific limitation on the specific crushing operation; physical crushing methods can be used to crush the particles until the particle size meets the requirements. This invention uses high-purity titanium particles, high-purity antimony blocks, and high-purity tellurium blocks as raw materials. On the one hand, the raw materials have low oxygen content and high purity; on the other hand, the production of titanium-antimony-tellurium alloy blocks and alloy powder through vacuum synthesis technology can make the prepared target material phase more uniform, thereby improving the phase change storage characteristics of the titanium-antimony-tellurium target material.

[0018] In this invention, the particle size of the titanium particles, antimony particles, and tellurium particles is preferably 1-10 mm; the shape of the titanium particles, antimony particles, and tellurium particles is preferably irregular. As one embodiment of this invention, the particle size of the titanium particles, antimony particles, and tellurium particles can be independently 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm.

[0019] In this invention, the preferred molar ratio of titanium particles, antimony particles, and tellurium particles is (0.2~0.4):(1~3):(2~4), more preferably (0.25~0.35):(1.5~2.5):(2.5~3.5), and even more preferably 0.3:2:3. By optimizing the atomic ratio of the raw materials, this invention can precisely control the molar ratio of titanium-antimony-tellurium, theoretically designing the atomic ratio to approach the optimal phase transition characteristics.

[0020] The present invention does not impose any particular limitation on the mixing method, as long as the titanium particles, antimony particles, and tellurium particles are mixed evenly. As one embodiment of the present invention, the mixing method may be stirring.

[0021] In this invention, the preferred sintering operation is to load the mixed particles into a quartz glass tube, evacuate the tube, heat the end of the quartz tube, seal the tube to obtain a vacuum quartz tube, and finally place the vacuum quartz tube in a muffle furnace for sintering.

[0022] In this invention, the sintering method is as follows: The vacuum degree of sintering is controlled to be ≤1 Pa. First, the temperature is increased to 690-800°C at a heating rate of 2-10°C / min and held for 3-4 hours. Then, the temperature is increased to 1000-1200°C at a heating rate of 5-15°C / min and held for 10-12 hours. Next, the temperature is decreased to 950-1050°C at a cooling rate of 1-3°C / min and held for 4-8 hours. Finally, the temperature is cooled to room temperature in the furnace. Preferably, the vacuum degree of sintering is controlled to be ≤1 Pa. First, the temperature is increased to 700-780°C at a heating rate of 3-8°C / min and held for 3-4 hours. Then, the temperature is decreased to 950-1050°C at a cooling rate of 1-3°C / min and held for 4-8 hours. The temperature is increased to 1050-1150℃ at a heating rate of 8-12℃ / min and held for 10-12 hours. Then, the temperature is decreased to 980-1020℃ at a cooling rate of 2℃ / min and held for 4-8 hours. Finally, the temperature is cooled to room temperature in the furnace. More preferably, the vacuum degree of sintering is controlled to be ≤1Pa. The temperature is first increased to 720-750℃ at a heating rate of 5℃ / min and held for 3-4 hours. Then, the temperature is increased to 1100℃ at a heating rate of 10℃ / min and held for 10-12 hours. Then, the temperature is decreased to 1000℃ at a cooling rate of 2℃ / min and held for 4-8 hours. Finally, the temperature is cooled to room temperature in the furnace. This invention ensures complete melting of antimony and tellurium by first heating to 690-800℃, followed by holding at 1000-1200℃ to ensure the synthesis of TiSb and TiTe compounds from titanium and antimony, and titanium and tellurium, respectively. Subsequent cooling to 950-1050℃ and holding at this temperature ensures thorough homogenization of the synthesized Sb₂Te₃ with TiSb and TiTe. This invention optimizes the vacuum synthesis process by employing a segmented heat treatment process, first high and then low, to ensure the synthesis of titanium antimony and titanium telluride from titanium and antimony, and titanium and tellurium, respectively. Titanium antimony and titanium telluride exhibit better compatibility than metallic titanium with antimony telluride. Prolonged holding at high temperatures during synthesis ensures complete reaction, resulting in a target material where titanium is uniformly distributed within the grain boundaries of antimony telluride.

[0023] After obtaining the titanium-antimony-tellurium alloy block, the present invention pulverizes the titanium-antimony-tellurium alloy block to obtain alloy powder.

[0024] In this invention, the preferred method of pulverization is to first break the powder into small pieces using physical crushing, then ball mill it in a vacuum ball mill, and finally sieve it. This invention does not impose specific limitations on the physical crushing, grinding, and sieving operations; these can be determined based on the technical knowledge of those skilled in the art, as long as the particle size of the alloy powder meets the requirements. As one embodiment of this invention, the grinding balls used in the ball mill can be zirconia balls with a diameter of 5 mm; the vacuum degree of the ball mill can be ≤0.5 Pa; the rotation speed of the ball mill can be 300~350 rpm; and the ball milling time can be 4~6 hours.

[0025] In this invention, the particle size of the alloy powder is preferably 150-300 mesh. As one embodiment of this invention, the particle size of the alloy powder can be 150 mesh, 160 mesh, 170 mesh, 180 mesh, 190 mesh, 200 mesh, 210 mesh, 220 mesh, 230 mesh, 240 mesh, 250 mesh, 260 mesh, 270 mesh, 280 mesh, 290 mesh, or 300 mesh. By controlling the particle size of the alloy powder, this invention can improve the relative density of the target material.

[0026] After obtaining the alloy powder, the present invention performs low-temperature vacuum hot pressing sintering on the alloy powder to obtain a phase change memory material titanium-antimony-tellurium target.

[0027] In this invention, the low-temperature vacuum hot pressing sintering is preferably carried out in a vacuum hot pressing furnace. This invention does not impose any special limitations on the specific model or source of the vacuum hot pressing furnace; any commercially available vacuum hot pressing furnace well-known to those skilled in the art can be used.

[0028] In this invention, the holding temperature of the low-temperature vacuum hot pressing sintering is 500~650℃; the vacuum degree of the low-temperature vacuum hot pressing sintering is ≤1Pa; the pressure of the low-temperature vacuum hot pressing sintering is 20~50MPa; the holding time of the low-temperature vacuum hot pressing sintering is 2~3h; and the cooling method of the low-temperature vacuum hot pressing sintering is preferably furnace cooling. In one embodiment of the present invention, the holding temperature for the low-temperature vacuum hot pressing sintering can be 500℃, 520℃, 540℃, 550℃, 560℃, 580℃, 600℃, 620℃, 640℃, or 650℃; the pressure for the low-temperature vacuum hot pressing sintering can be 20MPa, 22MPa, 25MPa, 28MPa, 30MPa, 32MPa, 35MPa, 38MPa, 40MPa, 42MPa, 45MPa, 48MPa, or 50MPa; and the holding time for the low-temperature vacuum hot pressing sintering can be 2h, 2.5h, or 3h. This invention optimizes the vacuum hot pressing process. By using the low-temperature vacuum hot pressing process, it prevents the target material from growing grains due to high temperatures. Combined with the long holding time, it ensures that the target material's relative density RD ≥ 95%.

[0029] The present invention preferably also includes precision machining of the product obtained by low-temperature vacuum hot pressing sintering. The present invention does not impose any special limitations on the specific operations of the precision machining; the machining can be performed according to the technical knowledge of those skilled in the art, as long as the shape and size of the phase change memory material titanium-antimony-tellurium target meet the requirements.

[0030] In this invention, the phase change memory material, titanium-antimony-tellurium target, is preferably stored in vacuum packaging. Vacuum packaging helps to prevent oxidation in air.

[0031] In this invention, the molar ratio of titanium, antimony, and tellurium in the titanium-antimony-tellurium target for phase change memory is preferably (0.2~0.4):(1~3):(2~4), more preferably (0.25~0.35):(1.5~2.5):(2.5~3.5), and even more preferably 0.3:2:3. In this invention, the titanium-antimony-tellurium target for phase change memory has a relative density RD ≥ 95%, a purity ≥ 99.95%, and an oxygen content ≤ 1000 ppm. The titanium-antimony-tellurium target for phase change memory prepared by the method provided in this invention can improve thin film deposition efficiency and data retention.

[0032] The preparation method provided by this invention employs a segmented heat treatment process, first high and then low, to ensure that titanium and antimony, and titanium and tellurium, are first synthesized into titanium antimonide and titanium telluride respectively. Titanium antimonide and titanium telluride exhibit better compatibility than metallic titanium and antimony telluride. Prolonged heat treatment during synthesis ensures complete reaction, resulting in a uniform distribution of titanium within the grain boundaries of antimony telluride after the target material is prepared. Furthermore, low-temperature vacuum hot-pressing sintering prevents high-temperature grain growth in the target material, and prolonged pressure holding ensures a more uniform phase composition. This yields a high-purity, low-oxygen-content titanium-antimony-tellurium target material with a relative density ≥95%, resulting in superior quality indicators and improved thin film deposition efficiency and performance. The preparation method provided by this invention has a simple production process and reduces production costs.

[0033] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] Example 1 A method for preparing a phase change memory material titanium-antimony-tellurium target comprises the following steps: (1) High-purity antimony blocks and high-purity tellurium blocks with a purity of 99.99% are crushed by physical crushing method to obtain antimony particles and tellurium particles with a particle size of 1~10mm and irregular shape. Titanium particles, antimony particles and tellurium particles are mixed to obtain mixed particles. The mixed particles are loaded into a quartz glass tube, and a vacuum is drawn to a vacuum degree ≤1Pa. Then the end of the quartz tube is heated and sealed to obtain a vacuum quartz tube. Finally, the vacuum quartz tube is placed in a muffle furnace for sintering to obtain a titanium-antimony-tellurium alloy block. The particle size of the titanium particles is 1~10mm. The purity of the titanium particles, antimony particles and tellurium particles is 99.99%, and the molar ratio of titanium particles, antimony particles and tellurium particles is 0.3:2:3. The sintering method in step (1) is as follows: control the vacuum degree of sintering to ≤1Pa, first heat up to 800℃ at a heating rate of 5℃ / min, hold for 3h, then heat up to 1200℃ at a heating rate of 10℃ / min, hold for 10h, then cool down to 980℃ at a cooling rate of 2℃ / min, hold for 7h, and finally cool down to room temperature with the furnace. (2) The titanium-antimony-tellurium alloy block obtained in step (1) is first crushed into small pieces by physical crushing, then put into a vacuum ball mill for ball milling, and finally sieved to obtain alloy powder with a particle size of 150~300 mesh; the grinding balls used in the ball mill are zirconia balls with a diameter of 5mm, the vacuum degree of the ball mill is ≤0.5Pa, the rotation speed of the ball mill is 300rpm, and the ball milling time is 6h; (3) The alloy powder obtained in step (2) is subjected to low-temperature vacuum hot pressing sintering in a vacuum hot pressing furnace, cooled to room temperature with the furnace, and then precision machined according to the required shape and size to obtain the phase change storage material titanium-antimony-tellurium target, which is then vacuum packaged and stored. The holding temperature of the low-temperature vacuum hot pressing sintering is 600℃, the vacuum degree is ≤1Pa, the pressure is 30MPa, and the holding time is 3h.

[0035] Example 2 A method for preparing a phase change memory material titanium-antimony-tellurium target comprises the following steps: (1) High-purity antimony blocks and high-purity tellurium blocks with a purity of 99.99% are crushed by physical crushing method to obtain antimony particles and tellurium particles with a particle size of 1~10mm and irregular shape. Titanium particles, antimony particles and tellurium particles are mixed to obtain mixed particles. The mixed particles are loaded into a quartz glass tube, and a vacuum is drawn to a vacuum degree ≤1Pa. Then the end of the quartz tube is heated and sealed to obtain a vacuum quartz tube. Finally, the vacuum quartz tube is placed in a muffle furnace for sintering to obtain a titanium-antimony-tellurium alloy block. The particle size of the titanium particles is 1~10mm. The purity of the titanium particles, antimony particles and tellurium particles is 99.99%, and the molar ratio of titanium particles, antimony particles and tellurium particles is 0.3:2:3. The sintering method in step (1) is as follows: control the vacuum degree of sintering to ≤1Pa, first heat up to 750℃ at a heating rate of 5℃ / min, hold for 3.5h, then heat up to 1100℃ at a heating rate of 10℃ / min, hold for 11h, then cool down to 1000℃ at a cooling rate of 2℃ / min, hold for 6h, and finally cool down to room temperature with the furnace. (2) The titanium-antimony-tellurium alloy block obtained in step (1) is first crushed into small pieces by physical crushing method, then put into a vacuum ball mill for ball milling, and finally screened to obtain alloy powder with a particle size of 150~300 mesh; the grinding balls used in the ball mill are zirconia balls with a diameter of 5mm, the vacuum degree of the ball mill is ≤0.5Pa, the rotation speed of the ball mill is 350rpm, and the ball milling time is 4h; (3) The alloy powder obtained in step (2) is subjected to low-temperature vacuum hot pressing sintering in a vacuum hot pressing furnace, cooled to room temperature with the furnace, and then precision machined according to the required shape and size to obtain the phase change storage material titanium-antimony-tellurium target, which is then vacuum packaged and stored; the holding temperature of the low-temperature vacuum hot pressing sintering is 600℃, the vacuum degree is ≤1Pa, the pressure is 40MPa, and the holding time is 2.5h.

[0036] Example 3 A method for preparing a phase change memory material titanium-antimony-tellurium target comprises the following steps: (1) High-purity antimony blocks and high-purity tellurium blocks with a purity of 99.99% are crushed by physical crushing method to obtain antimony particles and tellurium particles with a particle size of 1~10mm and irregular shape. Titanium particles, antimony particles and tellurium particles are mixed to obtain mixed particles. The mixed particles are loaded into a quartz glass tube, and a vacuum is drawn to a vacuum degree ≤1Pa. Then the end of the quartz tube is heated and sealed to obtain a vacuum quartz tube. Finally, the vacuum quartz tube is placed in a muffle furnace for sintering to obtain a titanium-antimony-tellurium alloy block. The particle size of the titanium particles is 1~10mm. The purity of the titanium particles, antimony particles and tellurium particles is 99.99%, and the molar ratio of titanium particles, antimony particles and tellurium particles is 0.3:2:3. The sintering method in step (1) is as follows: control the vacuum degree of sintering to ≤1Pa, first heat up to 780℃ at a heating rate of 5℃ / min, hold for 3h, then heat up to 1150℃ at a heating rate of 10℃ / min, hold for 11h, then cool down to 1030℃ at a cooling rate of 2℃ / min, hold for 6h, and finally cool down to room temperature with the furnace. (2) The titanium-antimony-tellurium alloy block obtained in step (1) is first crushed into small pieces by physical crushing, then put into a vacuum ball mill for ball milling, and finally screened to obtain alloy powder with a particle size of 150~300 mesh; the grinding balls used in the ball mill are zirconia balls with a diameter of 5mm, the vacuum degree of the ball mill is ≤0.5Pa, the rotation speed of the ball mill is 330rpm, and the ball milling time is 5h; (3) The alloy powder obtained in step (2) is subjected to low-temperature vacuum hot pressing sintering in a vacuum hot pressing furnace, cooled to room temperature with the furnace, and then precision machined according to the required shape and size to obtain the phase change storage material titanium-antimony-tellurium target, which is then vacuum packaged and stored; the holding temperature of the low-temperature vacuum hot pressing sintering is 550℃, the vacuum degree is ≤1Pa, the pressure is 40MPa, and the holding time is 3h.

[0037] Comparative Example 1 A method for preparing a phase change memory material titanium-antimony-tellurium target comprises the following steps: (1) High-purity antimony blocks and high-purity tellurium blocks with a purity of 99.99% are crushed by physical crushing method to obtain antimony particles and tellurium particles with a particle size of 1~10mm and irregular shape. Titanium particles, antimony particles and tellurium particles are mixed to obtain mixed particles. The mixed particles are loaded into a quartz glass tube, and a vacuum is drawn to a vacuum degree ≤1Pa. Then the end of the quartz tube is heated and sealed to obtain a vacuum quartz tube. Finally, the vacuum quartz tube is placed in a muffle furnace for sintering to obtain a titanium-antimony-tellurium alloy block. The particle size of the titanium particles is 1~10mm. The purity of the titanium particles, antimony particles and tellurium particles is 99.99%, and the molar ratio of titanium particles, antimony particles and tellurium particles is 0.3:2:3. The sintering method in step (1) is as follows: control the vacuum degree of sintering to ≤1Pa, heat up to 1200℃ at a heating rate of 5℃ / min, hold for 20h, and then cool to room temperature with the furnace. (2) The titanium-antimony-tellurium alloy block obtained in step (1) is first crushed into small pieces by physical crushing, then put into a vacuum ball mill for ball milling, and finally sieved to obtain alloy powder with a particle size of 150~300 mesh; the grinding balls used in the ball mill are zirconia balls with a diameter of 5mm, the vacuum degree of the ball mill is ≤0.5Pa, the rotation speed of the ball mill is 300rpm, and the ball milling time is 6h; (3) The alloy powder obtained in step (2) is subjected to low-temperature vacuum hot pressing sintering in a vacuum hot pressing furnace, cooled to room temperature with the furnace, and then precision machined according to the required shape and size to obtain the phase change storage material titanium-antimony-tellurium target, which is then vacuum packaged and stored. The holding temperature of the low-temperature vacuum hot pressing sintering is 600℃, the vacuum degree is ≤1Pa, the pressure is 30MPa, and the holding time is 3h.

[0038] Comparative Example 2 A method for preparing a phase change memory material titanium-antimony-tellurium target comprises the following steps: (1) High-purity antimony blocks and high-purity tellurium blocks with a purity of 99.99% are crushed by physical crushing method to obtain antimony particles and tellurium particles with a particle size of 1~10mm and irregular shape. The antimony particles and tellurium particles are mixed to obtain mixed particles. The mixed particles are loaded into a quartz glass tube, and a vacuum is drawn to a vacuum degree ≤1Pa. Then the end of the quartz tube is heated and sealed to obtain a vacuum quartz tube. Finally, the vacuum quartz tube is placed in a muffle furnace for sintering to obtain an antimony-tellurium alloy block. The purity of the antimony particles and tellurium particles is 99.99%, and the molar ratio of antimony particles to tellurium particles is 2:3. The sintering method in step (1) is as follows: control the vacuum degree of sintering to ≤1Pa, first heat up to 800℃ at a heating rate of 5℃ / min, hold for 3h, then heat up to 1200℃ at a heating rate of 10℃ / min, hold for 17h, and finally cool down to room temperature with the furnace. (2) The antimony-tellurium alloy block obtained in step (1) is first crushed into small pieces by physical crushing method, and then mixed with purchased titanium powder of 150~300 mesh. The molar ratio of titanium, antimony and tellurium is controlled to be 0.3:2:3. Then it is put into a vacuum ball mill for ball milling, and finally sieved to obtain a mixed powder with a particle size of 150~300 mesh. The grinding balls used in the ball mill are zirconia balls with a diameter of 5 mm. The vacuum degree of the ball mill is ≤0.5 Pa, the rotation speed of the ball mill is 300 rpm, and the ball milling time is 6 h. (3) The mixed powder obtained in step (2) is subjected to low-temperature vacuum hot pressing sintering in a vacuum hot press furnace, cooled to room temperature with the furnace, and then precision machined according to the required shape and size to obtain the phase change storage material titanium-antimony-tellurium target, which is then vacuum packaged and stored; the low-temperature vacuum hot pressing sintering temperature is 600℃, the vacuum degree is ≤1Pa, the pressure is 30MPa, and the holding time is 3h.

[0039] Comparative Example 3 A method for preparing a phase change memory material titanium-antimony-tellurium target comprises the following steps: (1) Commercially available titanium-antimony-tellurium alloy blocks are first crushed into small pieces by physical crushing, then placed in a vacuum ball mill for ball milling, and finally sieved to obtain alloy powder with a particle size of 150~300 mesh; the molar ratio of titanium, antimony and tellurium in the titanium-antimony-tellurium alloy blocks is 0.3:2:3; the grinding balls used for ball milling are zirconia balls with a diameter of 5 mm, the vacuum degree of ball milling is ≤0.5 Pa, the rotation speed of ball milling is 300 rpm, and the ball milling time is 6 h; (2) The alloy powder obtained in step (1) is subjected to low-temperature vacuum hot pressing sintering in a vacuum hot pressing furnace, cooled to room temperature with the furnace, and then precision machined according to the required shape and size to obtain the phase change storage material titanium-antimony-tellurium target, which is then vacuum packaged and stored. The holding temperature of the low-temperature vacuum hot pressing sintering is 600℃, the vacuum degree is ≤1Pa, the pressure is 30MPa, and the holding time is 3h.

[0040] Comparative Example 4 A method for preparing a phase change memory material titanium-antimony-tellurium target comprises the following steps: (1) High-purity antimony blocks and high-purity tellurium blocks with a purity of 99.99% are crushed by physical crushing method to obtain antimony particles and tellurium particles with a particle size of 1~10mm and irregular shape. Titanium particles, antimony particles and tellurium particles are mixed to obtain mixed particles. The mixed particles are loaded into a quartz glass tube, and a vacuum is drawn to a vacuum degree ≤1Pa. Then the end of the quartz tube is heated and sealed to obtain a vacuum quartz tube. Finally, the vacuum quartz tube is placed in a muffle furnace for sintering to obtain a titanium-antimony-tellurium alloy block. The particle size of the titanium particles is 1~10mm. The purity of the titanium particles, antimony particles and tellurium particles is 99.99%, and the molar ratio of titanium particles, antimony particles and tellurium particles is 0.3:2:3. The sintering method in step (1) is as follows: control the vacuum degree of sintering to ≤1Pa, first heat up to 800℃ at a heating rate of 5℃ / min, hold for 3h, then heat up to 1200℃ at a heating rate of 10℃ / min, hold for 10h, then cool down to 980℃ at a cooling rate of 2℃ / min, hold for 7h, and finally cool down to room temperature with the furnace. (2) The titanium-antimony-tellurium alloy block obtained in step (1) is first crushed into small pieces by physical crushing, then put into a vacuum ball mill for ball milling, and finally sieved to obtain alloy powder with a particle size of 150~300 mesh; the grinding balls used in the ball mill are zirconia balls with a diameter of 5mm, the vacuum degree of the ball mill is ≤0.5Pa, the rotation speed of the ball mill is 300rpm, and the ball milling time is 6h; (3) The alloy powder obtained in step (2) is subjected to low-temperature vacuum hot pressing sintering in a vacuum hot pressing furnace, cooled to room temperature with the furnace, and then precision machined according to the required shape and size to obtain the phase change storage material titanium-antimony-tellurium target, which is then vacuum packaged and stored; the holding temperature of the low-temperature vacuum hot pressing sintering is 800℃, the vacuum degree is ≤1Pa, the pressure is 30MPa, and the holding time is 3h.

[0041] The composition of the titanium-antimony-tellurium target material for phase change memory prepared in Example 1 was analyzed using ICP-OES and ICP-MS. The results are as follows: the relative density (RD) of the titanium-antimony-tellurium target material for phase change memory prepared in Example 1 is 98.2%, the purity is >99.95%, the oxygen content is ≤1000ppm, the Ti content is 2.25%, and the Sb content is 38.05%. The impurity element content and relative density results are shown in Table 1. Table 1. Impurity content and relative density of titanium-antimony-tellurium target materials for phase change memory prepared in the examples and comparative examples.

[0042] In Table 1, RD represents relative density and ND represents undetected.

[0043] As shown in Table 1, the titanium-antimony-tellurium target materials for phase change storage prepared in Examples 1-3 of this invention have low impurity element content, high purity, and a relative density of over 95%. Furthermore, a comparison of Examples 1-3 shows that adjusting the sintering and low-temperature vacuum hot-pressing sintering process parameters can significantly affect the impurity content and density of the titanium-antimony-tellurium target materials for phase change storage. A comparison between Example 1 and Comparative Example 1 shows that when titanium, antimony, and tellurium are fused using conventional sintering processes, uneven dispersion easily occurs, leading to incomplete elemental reactions and surface color differences after target preparation. Titanium cannot be uniformly distributed within the antimony telluride grain boundaries. Even with subsequent low-temperature vacuum hot-pressing sintering, the alloy's density decreases, and residual oxygen in the atmosphere more easily penetrates the material, reducing its purity. The comparison between Example 1 and Comparative Example 1 further demonstrates the advantages of this method. The comparison of Example 2 shows that Comparative Example 2, which uses commercially available titanium powder mixed with freshly prepared antimony-tellurium alloy blocks for powder preparation and then hot-pressing and sintering, results in a high oxygen content and poor relative density (compactness) in the prepared titanium-antimony-tellurium target material due to factors such as the high oxygen content of the commercially available titanium powder and the incompatibility of titanium with antimony telluride, which does not meet the technical requirements of this invention. The comparison between Example 1 and Comparative Example 3 shows that while directly using commercially available titanium-antimony-tellurium alloy blocks as raw materials for powder preparation and then preparing titanium-antimony-tellurium target materials is a simple process, the resulting titanium-antimony-tellurium target material has a high oxygen content and its compactness is far below the requirements of this invention. The comparison between Example 1 and Comparative Example 4 shows that increasing the temperature of low-temperature vacuum hot-pressing sintering will cause the target material grains to grow, leading to a decrease in the compactness of the material. At the same time, the higher temperature will easily allow some oxygen elements to enter the target material, increasing the oxygen content of the titanium-antimony-tellurium target material. The above analysis shows that by controlling the process parameters of sintering and low-temperature vacuum hot pressing sintering, the present invention can obtain high-purity, low-oxygen-content, and high-density phase change memory material titanium-antimony-tellurium target.

[0044] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a titanium-antimony-tellurium target for phase change memory, characterized in that, Includes the following steps: (1) Titanium particles, antimony particles and tellurium particles are mixed to obtain mixed particles, and then the mixed particles are sintered to obtain titanium-antimony-tellurium alloy blocks; (2) The titanium-antimony-tellurium alloy block obtained in step (1) is crushed to obtain alloy powder; (3) The alloy powder obtained in step (2) is subjected to low-temperature vacuum hot pressing sintering to obtain a phase change memory material titanium-antimony-tellurium target; The sintering method in step (1) is as follows: control the vacuum degree of sintering to ≤1Pa, first heat up to 690~800℃ at a heating rate of 2~10℃ / min, hold for 3~4h, then heat up to 1000~1200℃ at a heating rate of 5~15℃ / min, hold for 10~12h, then cool down to 950~1050℃ at a cooling rate of 1~3℃ / min, hold for 4~8h, and finally cool down to room temperature with the furnace. In step (3), the holding temperature of low-temperature vacuum hot pressing sintering is 500~650℃, the vacuum degree of low-temperature vacuum hot pressing sintering is ≤1Pa, the pressure of low-temperature vacuum hot pressing sintering is 20~50MPa, and the holding time of low-temperature vacuum hot pressing sintering is 2~3h.

2. The preparation method according to claim 1, characterized in that, In step (1), the particle size of titanium particles, antimony particles and tellurium particles is independently 1~10 mm.

3. The preparation method according to claim 1, characterized in that, In step (1), the purity of titanium particles, antimony particles and tellurium particles is independently ≥99.99%.

4. The preparation method according to claim 3, characterized in that, In step (1), the antimony particles are made by crushing high-purity antimony blocks, and the tellurium particles are made by crushing high-purity tellurium blocks.

5. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of titanium particles, antimony particles and tellurium particles is (0.2~0.4):(1~3):(2~4).

6. The preparation method according to claim 5, characterized in that, The molar ratio of the titanium particles, antimony particles, and tellurium particles is 0.3:2:

3.

7. The preparation method according to claim 1, characterized in that, In step (2), the crushing method is to first crush the material into small pieces by physical crushing, then put it into a vacuum ball mill for ball milling, and finally sieve it.

8. The preparation method according to claim 7, characterized in that, The grinding balls used in the ball mill are zirconia balls with a diameter of 5 mm. The vacuum degree of the ball mill is ≤0.5 Pa, the rotation speed of the ball mill is 300~350 rpm, and the grinding time is 4~6 h.

9. The preparation method according to claim 1, characterized in that, The particle size of the alloy powder in step (2) is 150~300 mesh.

10. The preparation method according to claim 1, characterized in that, In step (3), the molar ratio of titanium, antimony and tellurium in the phase change storage material titanium-antimony-tellurium target is (0.2~0.4):(1~3):(2~4).

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