Growth method of large-size indium crystal

Abstract

The invention discloses a growth method of a large-size indium crystal. The growth method comprises the following steps: step 1, pre-loading raw materials; 2, clamping the indium seed crystal; step 3, performing gas washing treatment in the furnace; 4, drossing the indium melt; step 5, crystal growth; and 6, cooling the crystal to obtain the large-size indium crystal. The method comprises the following steps: heating an indium material to melt the indium material, slagging off, removing slag crust on the surface of the melt, removing the adverse effect of oxide skin on the surface of the indium material melt on the stable growth of the indium crystal, slowly cooling, starting a crystal growth program, starting stable lifting after crystal shoulder expansion is finished, and accurately regulating and controlling a temperature field in the lifting process, so that the indium crystal growth process is finished. The method ensures that the indium crystal grows at a constant diameter, the phenomenon that the indium crystal is too large or too small does not occur, crystal growth failure is prevented, stable preparation of the large-size indium crystal is achieved, and the large-size indium crystal with the diameter larger than 25 mm and the height larger than 400 mm is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor material preparation, and particularly relates to a method for growing large-size indium crystals. Background Art

[0002] As a rare metal in Group IIIA, indium has excellent ductility, plasticity, corrosion resistance and electrical conductivity, and is widely used in display thin film targets, solar cell devices, alloy solders and electronic semiconductors, etc. In recent years, with the booming development of the semiconductor field, the purity requirement for indium has been increasing day by day. Crystal pulling is one of the important means to improve the purity of indium and is often used as the last process link in industrial production. However, the growth of indium crystals is a slow process. As the temperature of the melt surface decreases, the crystals gradually solidify and grow, requiring a relatively long preparation period, and it is difficult to control the shape and size of the crystals.

[0003] The shape and size of the crystal depend on the temperature field during the crystal growth process. The variation of the temperature field in the furnace is extremely likely to lead to the failure of crystal growth and it is impossible to successfully obtain crystals with regular shapes and large sizes. The commonly used pulling techniques at present usually control the temperature field in the furnace by adjusting the heating device, and often do not restrict the cold end, resulting in an unstable temperature field in the furnace and seriously affecting the crystal growth efficiency.

[0004] Therefore, a method for growing large-size indium crystals needs to be proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for growing large-size indium crystals in view of the deficiencies of the above-mentioned prior art. This method heats the indium material to melt it, and then skims the slag to remove the slag skin on the surface of the melt, eliminating the adverse effect of the oxide skin on the surface of the indium material melt on the stable growth of indium crystals. By slowly cooling and starting the crystal growth program, the temperature field during the pulling process is precisely controlled to ensure that the indium crystals grow with a constant diameter, without being too large or too small, preventing the failure of crystal growth, and realizing the stable preparation of large-size indium crystals.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a method for growing large-size indium crystals, characterized in that the method comprises the following steps: Step 1. Pre-install raw materials: Load the indium material into a quartz crucible, then place it in the heater in the crystal growth furnace, and then evenly fill the gap between the quartz crucible and the heater with high-temperature heat-insulating cotton to obtain a crystal growth furnace with a loaded quartz crucible; Step 2. Clamp an indium seed crystal: Install an indium seed crystal in the crystal growth furnace obtained in Step 1 to obtain a crystal growth furnace with an indium seed crystal; Step 3. Gas washing treatment in the furnace: Close the furnace lid of the crystal growth furnace with indium seeds obtained in Step 2, then turn on the mechanical pump to evacuate the air. When the vacuum degree drops below 10 Pa, turn on the molecular pump and evacuate to the set vacuum degree. Then turn off the molecular pump. After the molecular pump stops running, turn off the mechanical pump, open the gas charging valve, and fill the crystal growth furnace with argon gas to normal pressure, and repeat the above operations three times to complete the gas washing treatment. Among them, at the beginning of the last gas washing, heat the indium material; Step 4: Skim the slag from the indium melt: Raise the temperature heated in Step 3 in stages to 250°C - 300°C and keep it warm for 2 h - 3 h. Wait until the indium material in the quartz crucible is completely melted into an indium material melt, and use a slag skimming rod to skim the slag; Step 5: Crystal growth: Slowly cool the indium material melt after skimming the slag in Step 4 at a cooling rate of 2°C / min - 3°C / min, and start the crystal growth program. After the crystal shoulder expansion is completed, start stable pulling; Step 6: Crystal cooling: After the pulling in Step 5 is completed, turn off the heater and stop pulling. After the temperature in the crystal growth furnace drops to room temperature, open the furnace lid to obtain a large-sized indium crystal.

[0007] The present invention evenly fills the gap between the quartz crucible and the heater with high-temperature heat-insulating cotton to completely fix the position of the quartz crucible and prevent eccentricity during the growth of the indium crystal; through gas washing treatment, the atmosphere in the crystal growth furnace is replaced with argon gas to prevent oxidation during the growth of the indium crystal and ensure the purity of the indium crystal; by heating the indium material to melt it and skimming the slag, the slag skin on the surface of the melt is removed, and the adverse effect of the oxide skin on the surface of the indium material melt on the stable growth of the indium crystal is removed; by slowly cooling at a cooling rate of 2°C / min - 3°C / min and starting the crystal growth program, after the crystal shoulder expansion is completed, start stable pulling, and precisely control the temperature field during the pulling process to ensure that the indium crystal grows with a constant diameter, without being too large or too small, preventing crystal growth failure, and realizing the stable preparation of a large-sized indium crystal to obtain a large-sized indium crystal.

[0008] It should be noted that the temperature gradient of the crystal growth furnace is 100 K / cm.

[0009] The above method for growing a large-sized indium crystal is characterized in that the coaxiality between the quartz crucible and the heater in Step 1 is not greater than 0.5 mm. The present invention ensures the uniformity of heating by controlling the coaxiality, and at the same time ensures that the quartz crucible does not deviate from the center during subsequent rotation, preventing the indium crystal from growing crooked.

[0010] The above-mentioned method for growing a large-sized indium crystal is characterized in that the preparation process of the indium seed crystal in step two is as follows: melting indium material and then casting it into an indium seed crystal mold, demolding after cooling to take out the indium seed crystal, and the indium seed crystal includes an indium seed crystal head and an indium seed crystal rod; the indium seed crystal mold includes a sleeve, a riser and a mold shell are respectively inserted at both ends of the sleeve, a through hole is opened in the center of the riser, a through hole is also opened in the center of the mold shell, and the end of the mold shell far from the sleeve is sealed, the upper end of the mold shell is of an inclined surface structure, and the riser and the mold shell do not contact. The present invention designs an indium seed crystal mold, and an internal cavity for indium seed crystal casting is formed by connecting through a sleeve, a riser and a mold shell. The part where the riser and the mold shell do not contact in the sleeve is the indium seed crystal head. The inclined surface structure at the upper end of the mold shell makes there also be an inclined surface at the part where the lower part of the indium seed crystal head is connected to the indium seed crystal rod, which is convenient for clamping with the indium seed crystal fixture. The mold shell with one end sealed constitutes the indium seed crystal rod part. After the indium seed crystal mold casts indium material and cools and solidifies, the riser part is cut off to obtain the indium seed crystal; the present invention designs the indium seed crystal into a structure of an indium seed crystal head and an indium seed crystal rod, wherein the indium seed crystal head is convenient for connecting with the indium seed crystal fixture, and the contact area between the indium seed crystal and the cold source rod is increased, so that the heat of the indium crystal can be unidirectionally transferred to the cold source rod through the indium seed crystal rod, realizing the unidirectional and stable conduction of the internal heat flow in the furnace, and the indium seed crystal rod is convenient for leading out the indium crystal from the indium material melt.

[0011] The above-mentioned method for growing a large-sized indium crystal is characterized in that the process of installing the indium seed crystal in step three is as follows: placing the indium seed crystal inside the indium seed crystal fixture, and then tightening the indium seed crystal fixture so that the top surface of the indium seed crystal head is completely attached to the bottom surface of the cold source rod, and the side surface of the indium seed crystal head is completely attached to the inner surface of the indium seed crystal fixture; the indium seed crystal fixture is of a cylindrical structure, and the lower part is an inclined surface matching the indium seed crystal head, and the dimensional tolerance between the size of the indium seed crystal head and the inner cavity of the indium seed crystal fixture is not greater than 0.05 mm. In the present invention, the top surface of the indium seed crystal head is completely attached to the bottom surface of the cold source rod. The cold source rod is a rod through which cooling water passes. Making the top surface of the indium seed crystal head completely attached to the bottom surface of the cold source rod reduces the temperature at the indium seed crystal head and is convenient for leading out the indium crystal from the indium material melt. In the present invention, there is an internal thread inside the indium seed crystal fixture. Tightening the indium seed crystal fixture makes the side surface of the indium seed crystal head completely attached to the inner surface of the indium seed crystal fixture. The present invention sets the indium seed crystal fixture as a cylindrical structure, and the lower part is an inclined surface matching the indium seed crystal head, which is convenient for the indium seed crystal rod to pass through and enables the indium seed crystal head to be clamped with the indium seed crystal fixture. The present invention controls the dimensional tolerance between the size of the indium seed crystal head and the inner cavity of the indium seed crystal fixture to make the sizes of the indium seed crystal head and the indium seed crystal fixture match. When the indium seed crystal head is clamped into the indium seed crystal fixture, it fits tightly, ensuring the stability during subsequent lifting.

[0012] The above-mentioned method for growing a large-sized indium crystal is characterized in that the time for the molecular pump to evacuate in step three is 20 min to 30 min, and the set vacuum degree is lower than 1×10 -3Pa. In the present invention, the mechanical pump and the molecular pump are used alternately to maintain the vacuum degree below 1×10 -3 Pa, and the vacuum pumping effect is ensured by controlling the vacuum pumping time of the molecular pump, thereby ensuring the purity of the large-sized indium crystal.

[0013] In the above-mentioned method for growing a large-sized indium crystal, it is characterized in that the heating temperature in step three is 80°C to 100°C. In the present invention, when the last gas washing starts, the indium material is heated, and the heating temperature is controlled to evaporate and extract the water vapor remaining in the heat preservation cotton or other materials in the crystal growth furnace, further ensuring the purity of the large-sized indium crystal.

[0014] In the above-mentioned method for growing a large-sized indium crystal, it is characterized in that the heating temperature in step four is increased in stages as follows: first heated to 200°C and kept warm for 30 min, and then heated to 250°C to 300°C. In the present invention, by increasing the heating temperature in stages, first heating to a lower temperature and keeping warm to make the temperature in the crystal growth furnace uniform, and then continuing to heat up, the temperature uniformity in the crystal growth furnace is ensured.

[0015] In the above-mentioned method for growing a large-sized indium crystal, it is characterized in that the slag skimming rod in step four has an I-shaped frame structure, one end is provided with a corrugated pipe and a rotating handle and is located outside the crystal growth furnace, and one end is provided with a slag skimming hand and is located inside the crystal growth furnace; the slag skimming process is as follows: the slag skimming hand is inserted into the indium material melt and stirred clockwise or counterclockwise. After stirring 5 to 10 circles, the slag skimming hand is lifted out of the surface of the indium material melt. After the surface of the indium material melt is stationary, the slag skimming hand is inserted 3 to 5 mm from the surface of the indium material melt, and the quartz crucible is rotated to make the slag skin on the surface of the indium material melt cover the surface of the slag skimming hand. Then the slag skimming hand is lifted out of the surface of the indium material melt to remove the slag skin. Repeat the above operation until there is no slag skin on the surface of the indium material melt and it is like a mirror surface. In the present invention, by controlling the structure of the slag skimming rod, the slag skimming hand is located inside the crystal growth furnace and is used to remove the slag skin on the surface of the indium material melt, and the rotating handle is located outside the crystal growth furnace and is used to link and operate the slag skimming hand, which can realize the rotation and up and down movement of the slag skimming hand. The corrugated pipe plays a role in ensuring sealing when the slag skimming rod is rotated; in the present invention, by controlling the slag skimming process, removing the slag skin on the melt surface, removing the oxide skin on the surface of the indium material melt, removing the adverse effects on the stable growth of the crystal, and realizing the stable preparation of the large-sized indium crystal.

[0016] In the above-mentioned method for growing a large-sized indium crystal, it is characterized in that the temperature reduction in step five is to reduce the temperature of the indium material melt to 150°C to 160°C. In the present invention, by controlling the temperature reduction of the indium material melt, the stable pulling of the indium crystal is ensured, and the phenomena of crystal breakage or abnormal growth do not occur.

[0017] The above-mentioned method for growing a large-sized indium crystal is characterized in that, in step six, the diameter of the large-sized indium crystal is greater than 25 mm and the height is greater than 400 mm. The present invention realizes the preparation of a large-sized indium crystal.

[0018] The present invention has the following advantages compared with the prior art: 1. In the present invention, the indium material is heated to melt, and slag is skimmed off to remove the slag skin on the surface of the melt and the adverse effect of the oxide skin on the surface of the indium material melt on the stable growth of the indium crystal. By slowly cooling and starting the crystal growth program, after the crystal shoulder expansion is completed, stable pulling is started, and the temperature field during the pulling process is precisely controlled to ensure that the indium crystal grows with a constant diameter without being too large or too small, preventing crystal growth failure, and realizing the stable preparation of a large-sized indium crystal to obtain a large-sized indium crystal.

[0019] 2. In the present invention, by designing the indium seed crystal mold and the preparation process of the indium seed crystal, the structure of the indium seed crystal is controlled. The indium seed crystal head is convenient for connecting with the indium seed crystal clamp, and the contact area between the indium seed crystal and the cold source rod is increased, so that the heat of the indium crystal can be unidirectionally transferred to the cold source rod through the indium seed crystal rod, realizing the unidirectional stable conduction of the internal heat flow in the furnace and the smooth advancement of the solid / liquid interface, which is beneficial to the precise control of the temperature field, and can ensure the stable growth of the crystal within a large size range. The indium seed crystal rod is convenient for pulling out the indium crystal from the indium material melt.

[0020] 3. In the present invention, the heating temperature is increased in stages and sub-stages. First, it is heated to a lower temperature and kept warm to make the temperature in the crystal growth furnace uniform, and then the temperature is continued to be increased, ensuring the uniformity of the temperature in the crystal growth furnace.

[0021] 4. In the present invention, by controlling the structure of the slag skimming rod, the slag skimming hand is located inside the crystal growth furnace and is used to remove the slag skin on the surface of the indium material melt. The rotating handle is located outside the crystal growth furnace and is used for linkage operation of the slag skimming hand, which can realize the rotation and up-and-down movement of the slag skimming hand. The bellows plays a role in ensuring sealing when the slag skimming rod rotates; by controlling the slag skimming process, the slag skin on the surface of the melt is removed, the oxide skin on the surface of the indium material melt is removed, and the adverse effect on the stable growth of the crystal is removed, realizing the stable preparation of a large-sized indium crystal.

[0022] The technical solution of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0023] Figure 1 It is a flowchart of the method for growing a large-sized indium crystal of the present invention.

[0024] Figure 2 It is a schematic structural diagram of the indium seed crystal mold of the present invention.

[0025] Figure 3 It is a schematic structural diagram of the indium seed crystal of the present invention.

[0026] Figure 4 This is a schematic structural diagram of the indium seed crystal fixture of the present invention.

[0027] Figure 5 This is a schematic diagram of the positional relationship among the indium seed crystal, the indium seed crystal fixture, the cold source rod, and the quartz crucible of the present invention.

[0028] Figure 6 This is a schematic structural diagram of the slag skimming rod of the present invention.

[0029] Figure 7 This is a macroscopic view of the large-sized indium crystal prepared in Example 1 of the present invention.

[0030] Description of the reference numerals: 1 - indium seed crystal head; 2 - indium seed crystal rod; 3 - sleeve; 4 - riser; 5 - mold shell; 6 - indium seed crystal fixture; 7 - slag skimming rod; 8 - bellows; 9 - rotating handle; 10 - slag skimming hand; 11 - cold source rod; 12 - quartz crucible; 13 - indium melt. Detailed implementation manners

[0031] Figure 1 This is a flow chart of the method for growing a large-sized indium crystal of the present invention. As can be seen from Figure 1 it, the present invention first pre-installs the raw materials, then clamps the indium seed crystal, then performs gas washing treatment in the furnace, then skims the slag from the indium melt, grows the crystal, and finally cools the crystal to obtain a large-sized indium crystal.

[0032] Figure 2 This is a schematic structural diagram of the indium seed crystal mold of the present invention. As can be seen from Figure 2 it, the indium seed crystal mold includes a sleeve, and a riser and a mold shell are respectively inserted at both ends of the sleeve. A through hole is provided in the center of the riser, and a through hole is also provided in the center of the mold shell. The end of the mold shell away from the sleeve is sealed. The upper end of the mold shell is of an inclined surface structure, and the riser and the mold shell do not contact.

[0033] Figure 3 This is a schematic structural diagram of the indium seed crystal of the present invention. As can be seen from Figure 3 it, the indium seed crystal includes an indium seed crystal head and an indium seed crystal rod.

[0034] Figure 4 This is a schematic structural diagram of the indium seed crystal fixture of the present invention. As can be seen from Figure 4 it, the indium seed crystal fixture is of a cylindrical structure, and the lower part is an inclined surface that cooperates with the indium seed crystal head.

[0035] Figure 5 This is a schematic diagram of the positional relationship among the indium seed crystal, the indium seed crystal fixture, the cold source rod, and the quartz crucible of the present invention. As can be seen from Figure 5It can be seen that the indium seed crystal is placed inside the indium seed crystal fixture, the top surface of the indium seed crystal head is completely attached to the bottom surface of the cold source rod, and the side surface of the indium seed crystal head is completely attached to the inner surface of the indium seed crystal fixture. The indium seed crystal rod extends into the quartz crucible and contacts the indium melt.

[0036] Figure 6 This is the structural schematic diagram of the slag skimming rod of the present invention. As can be seen from Figure 6 it, the slag skimming rod is of an I-shaped frame structure, with a bellows and a rotating handle at one end located outside the crystal growth furnace, and a slag skimming hand at the other end located inside the crystal growth furnace.

[0037] Example 1 This example includes the following steps: Step 1. Pre-assemble raw materials: Load 12 kg of indium material into the quartz crucible, then place it in the heater inside the crystal growth furnace, and then evenly fill the gap between the quartz crucible and the heater with high-temperature heat-insulating cotton to obtain a crystal growth furnace with a loaded quartz crucible; the coaxiality between the quartz crucible and the heater is not greater than 0.5 mm; Step 2. Clamp the indium seed crystal: Pour the melted indium material into the indium seed crystal mold, demold and take out the indium seed crystal after cooling. The indium seed crystal includes an indium seed crystal head and an indium seed crystal rod. Then install the indium seed crystal in the crystal growth furnace obtained in Step 1, place the indium seed crystal inside the indium seed crystal fixture, and then tighten the indium seed crystal fixture so that the top surface of the indium seed crystal head is completely attached to the bottom surface of the cold source rod, and the side surface of the indium seed crystal head is completely attached to the inner surface of the indium seed crystal fixture to obtain a crystal growth furnace with an indium seed crystal; the indium seed crystal mold includes a sleeve, with a riser and a mold shell inserted at both ends of the sleeve respectively. A through hole is provided in the center of the riser, and a through hole is also provided in the center of the mold shell. The end of the mold shell away from the sleeve is sealed. The upper end of the mold shell is of an inclined surface structure, and the riser and the mold shell do not contact; the indium seed crystal fixture is of a cylindrical structure, and the lower part is an inclined surface matching the indium seed crystal head. The dimensional tolerance between the size of the indium seed crystal head and the inner cavity of the indium seed crystal fixture is not greater than 0.05 mm; Step 3. Gas washing treatment inside the furnace: Close the furnace cover of the crystal growth furnace with an indium seed crystal obtained in Step 2, then turn on the mechanical pump to pump vacuum. When the vacuum degree drops below 10 Pa, turn on the molecular pump. The vacuum pumping time is 25 min, and pump vacuum until the vacuum degree is lower than 1×10 -3 Pa, then turn off the molecular pump. After the molecular pump stops running, turn off the mechanical pump, turn on the inflation valve, fill the inside of the crystal growth furnace with argon gas to normal pressure, and repeat the above operation three times to complete the gas washing treatment. Among them, when the last gas washing starts, heat the indium material, and the heating temperature is 90 °C; Step 4. Skim the indium melt: In step three, first heat the temperature to 200 °C and keep it warm for 30 minutes, then heat it to 280 °C and keep it warm for 2.5 hours. Wait until the indium material in the quartz crucible is completely melted into an indium material melt. Use a slag skimming rod to skim the slag. Insert the slag skimming hand deep into the indium material melt and stir clockwise or counterclockwise. After stirring 8 circles, lift the slag skimming hand out of the surface of the indium material melt. After the surface of the indium material melt is stationary, insert the slag skimming hand 4 mm from the surface of the indium material melt, and rotate the quartz crucible so that the slag skin on the surface of the indium material melt covers the surface of the slag skimming hand. Then lift the slag skimming hand out of the surface of the indium material melt and remove the slag skin. Repeat the above operations until there is no slag skin on the surface of the indium material melt and it shows a mirror surface; the slag skimming rod has an I-shaped frame structure, with one end provided with a bellows and a rotating handle and located outside the crystal growth furnace, and one end provided with a slag skimming hand and located inside the crystal growth furnace; Step Five: Crystal Growth Slowly cool the indium material melt after slag skimming in step four to 150 °C at a cooling rate of 3 °C / min, and start the crystal growth program. After the crystal shoulder broadening is completed, start stable pulling; Step Six: Crystal Cooling After the pulling in step five is completed, turn off the heater, stop pulling. After the temperature in the crystal growth furnace drops to room temperature, open the furnace lid to obtain a large-sized indium crystal.

[0038] After testing, the diameter of the large-sized indium crystal prepared in this embodiment is greater than 25 mm, and the height is greater than 400 mm.

[0039] Figure 7 This is the macroscopic view of the large-sized indium crystal prepared in this embodiment. From Figure 7 it can be seen that the diameter of the large-sized indium crystal prepared in this embodiment is greater than 25 mm, and the height is greater than 400 mm.

[0040] Example 2 This embodiment includes the following steps: Step One: Preload Raw Materials Load 15 kg of indium material into a quartz crucible, then place it in the heater inside the crystal growth furnace, and then evenly fill the gap between the quartz crucible and the heater with high-temperature heat-insulating cotton to obtain a crystal growth furnace with a loaded quartz crucible; the coaxiality between the quartz crucible and the heater is not greater than 0.5 mm; Step Two: Clamp the Indium Seed Crystal The indium material is melted and then cast into an indium seed crystal mold. After cooling, the mold is removed to obtain the indium seed crystal. The indium seed crystal includes an indium seed crystal head and an indium seed crystal rod. Then, the indium seed crystal is installed in the crystal growth furnace obtained in Step 1. The indium seed crystal is placed inside an indium seed crystal fixture, and then the indium seed crystal fixture is tightened so that the top surface of the indium seed crystal head is completely attached to the bottom surface of the cold source rod, and the side surface of the indium seed crystal head is completely attached to the inner surface of the indium seed crystal fixture, obtaining a crystal growth furnace with an indium seed crystal. The indium seed crystal mold includes a sleeve. Pouring risers and a mold shell are respectively inserted at both ends of the sleeve. A through hole is provided in the center of the pouring riser, and a through hole is also provided in the center of the mold shell. The end of the mold shell away from the sleeve is sealed. The upper end of the mold shell is of an inclined surface structure, and the pouring riser and the mold shell do not contact. The indium seed crystal fixture is of a cylindrical structure, and the lower part is an inclined surface that fits the indium seed crystal head. The dimensional tolerance between the size of the indium seed crystal head and the inner cavity of the indium seed crystal fixture is not greater than 0.05 mm. Step 3. Gas washing treatment in the furnace: Close the furnace cover of the crystal growth furnace with the indium seed crystal obtained in Step 2, and then start the mechanical pump to pump vacuum. When the vacuum degree drops below 10 Pa, start the molecular pump. The vacuum pumping time is 20 min. Pump the vacuum until the vacuum degree is lower than 1×10 -3 Pa, then close the molecular pump. After the molecular pump stops running, close the mechanical pump, open the gas charging valve, and fill the crystal growth furnace with argon gas to normal pressure, and repeat the above operation three times to complete the gas washing treatment. Among them, at the beginning of the last gas washing, heat the indium material, and the heating temperature is 80 °C. Step 4. Skimming the indium melt: First heat the temperature in Step 3 to 200 °C and keep it warm for 30 min, then heat it to 300 °C and keep it warm for 2 h. Wait until the indium material in the quartz crucible is completely melted into an indium melt. Use a skimming rod to skim the slag. Insert the skimming hand deep into the indium melt and stir clockwise or counterclockwise. After stirring 10 circles, lift the skimming hand out of the surface of the indium melt. After the surface of the indium melt is stationary, insert the skimming hand 3 mm from the surface of the indium melt, rotate the quartz crucible so that the slag skin on the surface of the indium melt covers the surface of the skimming hand, and then lift the skimming hand out of the surface of the indium melt to remove the slag skin. Repeat the above operation until there is no slag skin on the surface of the indium melt and it is mirror-like. The skimming rod is of an I-shaped frame structure, with a bellows and a rotating handle at one end located outside the crystal growth furnace, and a skimming hand at the other end located inside the crystal growth furnace. Step 5. Crystal growth: Slowly cool the indium melt after skimming in Step 4 at a cooling rate of 2 °C / min to 152 °C, and start the crystal growth program. After the crystal shoulder expansion is completed, start stable lifting. Step 6. Crystal cooling: After the lifting in Step 5 is completed, turn off the heater and stop the lifting. After the temperature in the crystal growth furnace drops to room temperature, open the furnace lid to obtain a large-sized indium crystal.

[0041] After testing, the diameter of the large-sized indium crystal prepared in this embodiment is greater than 25 mm, and the height is greater than 400 mm.

[0042] Example 3 This embodiment includes the following steps: Step 1. Preload raw materials: Load 10 kg of indium material into a quartz crucible, then place it in the heater inside the crystal growth furnace, and then evenly fill the gap between the quartz crucible and the heater with high-temperature heat-insulating cotton to obtain a crystal growth furnace with a loaded quartz crucible; the coaxiality between the quartz crucible and the heater is not greater than 0.5 mm; Step 2. Clamp the indium seed crystal: Pour the melted indium material into an indium seed crystal mold, demold and take out the indium seed crystal after cooling. The indium seed crystal includes an indium seed crystal head and an indium seed crystal rod. Then install the indium seed crystal in the crystal growth furnace obtained in Step 1, place the indium seed crystal inside the indium seed crystal clamp, and then tighten the indium seed crystal clamp so that the top surface of the indium seed crystal head is completely attached to the bottom surface of the cold source rod, and the side surface of the indium seed crystal head is completely attached to the inner surface of the indium seed crystal clamp to obtain a crystal growth furnace with an indium seed crystal; the indium seed crystal mold includes a sleeve, and a riser and a mold shell are respectively inserted at both ends of the sleeve. A through hole is opened in the center of the riser, and a through hole is also opened in the center of the mold shell, and the end of the mold shell away from the sleeve is sealed. The upper end of the mold shell is a slope structure, and the riser and the mold shell do not contact; the indium seed crystal clamp is a cylindrical structure, and the lower part is a slope that matches the indium seed crystal head. The dimensional tolerance between the size of the indium seed crystal head and the inner cavity of the indium seed crystal clamp is not greater than 0.05 mm; Step 3. Gas washing treatment inside the furnace: Close the furnace lid of the crystal growth furnace with the indium seed crystal obtained in Step 2, then turn on the mechanical pump to pump vacuum. When the vacuum degree drops below 10 Pa, turn on the molecular pump, and the vacuum pumping time is 30 min. Pump vacuum until the vacuum degree is lower than 1×10 -3 Pa, then turn off the molecular pump. After the molecular pump stops running, turn off the mechanical pump, open the inflation valve, fill the inside of the crystal growth furnace with argon gas to atmospheric pressure, and repeat the above operation three times to complete the gas washing treatment. Among them, when the last gas washing starts, heat the indium material, and the heating temperature is 100 °C; Step 4. Skim the indium melt: In step three, first heat the temperature to 200 °C and keep it warm for 30 min, then heat it to 250 °C and keep it warm for 3 h. Wait until the indium material in the quartz crucible is completely melted into an indium material melt. Use a slag skimming rod to skim the slag. Insert the slag skimming hand into the interior of the indium material melt and stir it clockwise or counterclockwise. After stirring 5 circles, lift the slag skimming hand out of the surface of the indium material melt. After the surface of the indium material melt becomes stationary, insert the slag skimming hand 5 mm from the surface of the indium material melt, and rotate the quartz crucible so that the slag skin on the surface of the indium material melt covers the surface of the slag skimming hand. Then lift the slag skimming hand out of the surface of the indium material melt to remove the slag skin. Repeat the above operations until there is no slag skin on the surface of the indium material melt and it presents a mirror surface; the slag skimming rod has an I-shaped frame structure, with one end provided with a bellows and a rotating handle and located outside the crystal growth furnace, and one end provided with a slag skimming hand and located inside the crystal growth furnace; Step Five, Crystal Growth: Slowly cool the indium material melt after slag skimming in step four to 155 °C at a cooling rate of 2.5 °C / min, and start the crystal growth program. After the crystal shoulder expansion is completed, start stable lifting; Step Six, Crystal Cooling: After the lifting in step five is completed, turn off the heater, stop lifting. After the temperature in the crystal growth furnace drops to room temperature, open the furnace lid to obtain a large-sized indium crystal.

[0043] After testing, the diameter of the large-sized indium crystal prepared in this example is greater than 25 mm, and the height is greater than 400 mm.

[0044] Example 4 This example includes the following steps: Step One, Pre-install Raw Materials: Load 11 kg of indium material into a quartz crucible, then place it in the heater inside the crystal growth furnace, and then evenly fill the gap between the quartz crucible and the heater with high-temperature heat-insulating cotton to obtain a crystal growth furnace with a loaded quartz crucible; the coaxiality between the quartz crucible and the heater is not greater than 0.5 mm; Step Two, Clamp the Indium Seed Crystal: The indium material is melted and then cast into an indium seed crystal mold. After cooling, the mold is demolded to take out the indium seed crystal. The indium seed crystal includes an indium seed crystal head and an indium seed crystal rod. Then, the indium seed crystal is installed in the crystal growth furnace obtained in Step 1. The indium seed crystal is placed inside the indium seed crystal fixture, and then the indium seed crystal fixture is tightened so that the top surface of the indium seed crystal head is completely attached to the bottom surface of the cold source rod, and the side surface of the indium seed crystal head is completely attached to the inner surface of the indium seed crystal fixture, obtaining a crystal growth furnace with an indium seed crystal; the indium seed crystal mold includes a sleeve, and a riser and a mold shell are respectively inserted at both ends of the sleeve. A through hole is opened in the center of the riser, and a through hole is also opened in the center of the mold shell, and the end of the mold shell away from the sleeve is sealed. The upper end of the mold shell is of an inclined surface structure, and the riser and the mold shell do not contact; the indium seed crystal fixture is of a cylindrical structure, and the lower part is an inclined surface matching the indium seed crystal head. The dimensional tolerance between the size of the indium seed crystal head and the inner cavity of the indium seed crystal fixture is not greater than 0.05 mm; Step 3. Gas washing treatment in the furnace: Close the furnace cover of the crystal growth furnace with the indium seed crystal obtained in Step 2, and then start the mechanical pump to pump vacuum. When the vacuum degree drops below 10 Pa, start the molecular pump. The vacuum pumping time is 25 min, and pump vacuum until the vacuum degree is lower than 1×10 -3 Pa, then close the molecular pump. After the molecular pump stops running, close the mechanical pump, open the gas charging valve, and fill the crystal growth furnace with argon gas to normal pressure, and repeat the above operation three times to complete the gas washing treatment. Among them, when the last gas washing starts, heat the indium material, and the heating temperature is 85 °C; Step 4. Skimming the indium melt: First, heat the temperature in Step 3 to 200 °C and keep it warm for 30 min, then heat it to 260 °C and keep it warm for 2.5 h. Wait until the indium material in the quartz crucible is completely melted into an indium melt. Use a skimming rod to skim the slag. Insert the skimming hand deep into the indium melt and stir clockwise or counterclockwise. After stirring 7 circles, lift the skimming hand out of the surface of the indium melt. After the surface of the indium melt is stationary, insert the skimming hand 4 mm from the surface of the indium melt, and rotate the quartz crucible so that the slag skin on the surface of the indium melt covers the surface of the skimming hand. Then lift the skimming hand out of the surface of the indium melt to remove the slag skin. Repeat the above operation until there is no slag skin on the surface of the indium melt and it is like a mirror; the skimming rod is of an I-shaped frame structure, with a bellows and a rotating handle at one end and located outside the crystal growth furnace, and a skimming hand at the other end and located inside the crystal growth furnace; Step 5. Crystal growth: Slowly cool the indium melt after skimming in Step 4 at a cooling rate of 2 °C / min to 158 °C, and start the crystal growth program. After the crystal shoulder expansion is completed, start stable lifting; Step 6. Crystal cooling: After the lifting in Step 5 is completed, turn off the heater, stop the lifting, and after the temperature in the crystal growth furnace drops to room temperature, open the furnace lid to obtain a large-sized indium crystal.

[0045] After testing, the diameter of the large-sized indium crystal prepared in this embodiment is greater than 25 mm, and the height is greater than 400 mm.

[0046] Example 5 This embodiment includes the following steps: Step 1. Preload raw materials: Load 14 kg of indium material into a quartz crucible, then place it in the heater inside the crystal growth furnace, and then evenly fill the gap between the quartz crucible and the heater with high-temperature heat-insulating cotton to obtain a crystal growth furnace with a loaded quartz crucible; the coaxiality between the quartz crucible and the heater is not greater than 0.5 mm; Step 2. Clamp the indium seed crystal: Melt the indium material and pour it into the indium seed crystal mold. After cooling, demold and take out the indium seed crystal. The indium seed crystal includes an indium seed crystal head and an indium seed crystal rod. Then install the indium seed crystal in the crystal growth furnace obtained in Step 1, place the indium seed crystal inside the indium seed crystal clamp, and then tighten the indium seed crystal clamp so that the top surface of the indium seed crystal head is completely attached to the bottom surface of the cold source rod, and the side surface of the indium seed crystal head is completely attached to the inner surface of the indium seed crystal clamp to obtain a crystal growth furnace with an indium seed crystal; the indium seed crystal mold includes a sleeve, and a riser and a mold shell are respectively inserted at both ends of the sleeve. A through hole is opened in the center of the riser, and a through hole is also opened in the center of the mold shell, and the end of the mold shell away from the sleeve is sealed. The upper end of the mold shell is a slope structure, and the riser and the mold shell do not contact; the indium seed crystal clamp is a cylindrical structure, and the lower part is a slope matching the indium seed crystal head. The dimensional tolerance between the indium seed crystal head and the inner cavity of the indium seed crystal clamp is not greater than 0.05 mm; Step 3. Gas washing treatment inside the furnace: Close the furnace lid of the crystal growth furnace with the indium seed crystal obtained in Step 2, then turn on the mechanical pump to pump vacuum. When the vacuum degree drops below 10 Pa, turn on the molecular pump, and the vacuum pumping time is 25 min. Pump vacuum until the vacuum degree is lower than 1×10 -3 Pa, then turn off the molecular pump. After the molecular pump stops running, turn off the mechanical pump, open the inflation valve, and fill the crystal growth furnace with argon gas to atmospheric pressure, and repeat the above operation three times to complete the gas washing treatment. Among them, when the last gas washing starts, heat the indium material, and the heating temperature is 95 °C; Step 4. Skim the slag from the indium melt: In step 3, heat the temperature to 200 °C first and hold for 30 min, then heat to 270 °C and hold for 2.5 h. Wait until the indium material in the quartz crucible is completely melted into an indium material melt. Use a slag skimming rod to skim the slag. Insert the slag skimming hand deep into the indium material melt and stir clockwise or counterclockwise. After stirring 9 circles, lift the slag skimming hand out of the surface of the indium material melt. After the surface of the indium material melt is stationary, insert the slag skimming hand 5 mm from the surface of the indium material melt, and rotate the quartz crucible so that the slag skin on the surface of the indium material melt covers the surface of the slag skimming hand. Then lift the slag skimming hand out of the surface of the indium material melt to remove the slag skin. Repeat the above operations until there is no slag skin on the surface of the indium material melt and it shows a mirror surface. The slag skimming rod is of an I-shaped frame structure, with a bellows and a rotating handle at one end and located outside the crystal growth furnace, and a slag skimming hand at the other end and located inside the crystal growth furnace; Step 5. Crystal growth: Slowly cool the indium material melt skimmed in step 4 to 160 °C at a cooling rate of 3 °C / min, and start the crystal growth program. After the crystal shoulder expansion is completed, start stable lifting; Step 6. Crystal cooling: After the lifting in step 5 is completed, turn off the heater, stop lifting. After the temperature in the crystal growth furnace drops to room temperature, open the furnace lid to obtain a large-sized indium crystal.

[0047] After testing, the diameter of the large-sized indium crystal prepared in this embodiment is greater than 25 mm, and the height is greater than 400 mm.

[0048] The above is only a preferred embodiment of the present invention, and does not impose any limitation on the present invention. Any simple modification, change, and equivalent change made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for growing a large-sized indium crystal, characterized in that, The method comprises the following steps: Step 1, preloading raw materials: Load indium materials into a quartz crucible, then place it in a heater inside a crystal growth furnace, and then evenly fill the gap between the quartz crucible and the heater with high-temperature heat-insulating cotton to obtain a crystal growth furnace with a loaded quartz crucible; Step 2, clamping an indium seed crystal: Install an indium seed crystal in the crystal growth furnace obtained in Step 1 to obtain a crystal growth furnace with an indium seed crystal; Step 3, gas washing treatment inside the furnace: Close the furnace lid of the crystal growth furnace with an indium seed crystal obtained in Step 2, then turn on a mechanical pump to pump vacuum. When the vacuum degree drops below 10 Pa, turn on a molecular pump and pump vacuum to a set vacuum degree. Then turn off the molecular pump. After the molecular pump stops running, turn off the mechanical pump, turn on an inflation valve, fill the inside of the crystal growth furnace with argon gas to normal pressure, and repeat the above operation three times to complete the gas washing treatment. Among them, when the last gas washing starts, heat the indium materials; Step 4, skimming the indium melt: Gradually raise the temperature heated in Step 3 to 250°C - 300°C and keep it warm for 2 h - 3 h. Wait until the indium materials in the quartz crucible are completely melted into an indium material melt, and use a skimming rod to skim the slag; Step 5, crystal growth: Slowly cool the indium material melt after skimming in Step 4 at a cooling rate of 2°C / min - 3°C / min, and start the crystal growth program. After the crystal shoulder expansion ends, start stable pulling; Step 6, crystal cooling: After the pulling in Step 5 ends, turn off the heater and stop pulling. After the temperature inside the crystal growth furnace drops to room temperature, open the furnace lid to obtain a large-sized indium crystal.

2. The growth method of a large-size indium crystal according to claim 1, wherein The coaxiality between the quartz crucible and the heater described in Step 1 is not greater than 0.5 mm.

3. The growth method of a large-sized indium crystal according to claim 1, characterized in that, The preparation process of the indium seed crystal described in Step 2 is as follows: Melt indium materials and then cast them into an indium seed crystal mold. After cooling, demold to take out the indium seed crystal. The indium seed crystal includes an indium seed crystal head and an indium seed crystal rod; the indium seed crystal mold includes a sleeve, and a riser and a mold shell are respectively inserted at both ends of the sleeve. A through hole is opened in the center of the riser, and a through hole is also opened in the center of the mold shell. The end of the mold shell away from the sleeve is sealed. The upper end of the mold shell is a bevel structure, and the riser and the mold shell do not contact.

4. The growth method of a large-size indium crystal according to claim 3, characterized in that, The process of installing the indium seed crystal described in Step 2 is as follows: Place the indium seed crystal inside an indium seed crystal clamp, and then tighten the indium seed crystal clamp so that the top surface of the indium seed crystal head is completely attached to the bottom surface of the cold source rod, and the side surface of the indium seed crystal head is completely attached to the inner surface of the indium seed crystal clamp; the indium seed crystal clamp is a cylindrical structure, and the lower part is a bevel surface matching the indium seed crystal head. The dimensional tolerance between the size of the indium seed crystal head and the inner cavity of the indium seed crystal clamp is not greater than 0.05 mm.

5. The growth method of a large-size indium crystal according to claim 1, wherein, The time for the molecular pump to evacuate the vacuum in Step 3 is 20 min to 30 min, and the set vacuum degree is lower than 1×10 -3 Pa.

6. The growth method of a large-sized indium crystal according to claim 1, characterized in that The heating temperature described in Step 3 is 80°C - 100°C.

7. A method for growing a large-sized indium crystal according to claim 1, characterized in that, The temperature increase in Step 4 is carried out in stages as follows: First, heat to 200°C and keep it warm for 30 min, and then heat to 250°C - 300°C.

8. A method for growing a large-sized indium crystal according to claim 1, characterized in that, The slag scraping rod described in Step 4 is of an I-shaped frame structure, with a bellows and a rotating handle at one end, which is located outside the crystal growth furnace, and a slag scraping hand at the other end, which is located inside the crystal growth furnace; the process of slag scraping is as follows: the slag scraping hand is inserted deep into the indium material melt and stirred clockwise or counterclockwise. After stirring for 5 to 10 circles, the slag scraping hand is lifted out of the surface of the indium material melt. After the surface of the indium material melt is stationary, the slag scraping hand is inserted 3 to 5 mm from the surface of the indium material melt, and the quartz crucible is rotated to make the slag skin on the surface of the indium material melt cover the surface of the slag scraping hand. Then the slag scraping hand is lifted out of the surface of the indium material melt to remove the slag skin. Repeat the above operation until there is no slag skin on the surface of the indium material melt and it is mirror-like.

9. A method for growing a large-sized indium crystal according to claim 1, characterized in that, The temperature reduction in Step 5 is to reduce the temperature of the indium material melt to 150°C to 160°C.

10. A method for growing a large-sized indium crystal according to claim 1, characterized in that, The diameter of the large-sized indium crystal described in Step 6 is greater than 25 mm, and the height is greater than 400 mm.

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