Crystal growth device and growth method

Abstract

The invention provides a crystal growth device and a crystal growth method, and belongs to the technical field of crystal growth. According to the crystal growth method, the seed crystal is fixed to the seed crystal section, the growth crucible is rotated so that the seed crystal can still be located in the seed crystal section, at least part of the polycrystal material falls into the tail section, the polycrystal material falling into the tail section can be fully overheated in a partitioned heating mode, the temperature of the seed crystal located in the seed crystal section is strictly controlled, and the crystal growth efficiency is improved. And the temperature is below the melting point, so that complete melting is avoided. After the polycrystal material is completely molten, the growth crucible is rotated again, the molten polycrystal material falls into the shouldering section and is in contact with the seed crystal, and the polycrystal material close to the position of the seed crystal is subjected to sufficient overheating convection due to sufficient overheating of the polycrystal material, so that welding with the seed crystal is facilitated, and the seeding success rate of preparing large-size single crystals by adopting a seeding method is improved. The crystal growth method provided by the invention is suitable for growth of all types of crystal materials, and can solve the ubiquitous problem of insufficient overheating of polycrystal materials in the existing seeding method.

Description

Technical Field

[0001] This application relates to the technical field of crystal growth, and more specifically, to a crystal growth apparatus and a growth method. Background Art

[0002] In order to obtain large-size single crystals, the seed crystal method is generally used to prepare large-size single crystals at present. First, the single crystal material is prepared into a slender cylindrical structure and placed at the bottom of the crucible. Then, the prepared polycrystalline material is loaded into the crucible. During crystal growth, the heating temperature of the furnace body is adjusted so that the temperature at the position half of the height of the seed crystal is exactly the melting point of the crystal. Half of the seed crystal will melt, and then crystal growth will occur. The crystal grains will grow along the single crystal of the seed crystal, thereby obtaining a single crystal and improving the success rate of crystal growth.

[0003] Although this method has great advantages in preparing single crystals, it also brings some problems. The biggest problem is that the seed crystal cannot be completely melted, otherwise it will not be able to play the role of guiding crystal growth. Therefore, the polycrystalline material near the seed crystal position cannot be heated to a high enough temperature during heating and can only be heated to a temperature close to the growth point. The polycrystalline material here cannot be fully superheated, and the chemical bonds between the internal components cannot be completely broken. Therefore, compared with the high-temperature region, this is the cold end, and there will be a problem of uneven mixing of materials, resulting in uneven composition. And because the temperature of the polycrystalline material here is relatively low, it will have a large viscosity, and the convection is not sufficient, which will reduce the success rate of guiding crystal growth. Summary of the Invention

[0004] This application provides a crystal growth apparatus and a growth method, which can improve the success rate of guiding crystal growth of large-size single crystals prepared by the seed crystal method.

[0005] The embodiments of this application are implemented as follows:

[0006] In a first aspect, an embodiment of this application provides a crystal growth apparatus, which includes a growth crucible, a rotating shaft, a first heater, a second heater, and a third heater. The growth crucible includes a seed crystal section, a shoulder-forming section, and a tail section that extend sequentially along its length direction. A cavity with a boss structure is formed inside the seed crystal section. The rotating shaft is connected to the shoulder-forming section of the growth crucible and is used to rotate the growth crucible along its radial direction. The first heater, the second heater, and the third heater are respectively used to heat the seed crystal section, the shoulder-forming section, and the tail section.

[0007] In the above technical solution, the crystal growth device of the present application can be used to grow large-size single crystals. The cavity of the boss structure inside the seed crystal section can fix the seed crystal in the seed crystal section of the growth crucible. When heating the polycrystalline material, the growth crucible is rotated by the rotating shaft so that the position of the seed crystal section is higher than that of the tail section, and at least part of the polycrystalline material falls into the tail section. Further, the seed crystal is heated below the melting point of the crystal and the polycrystalline material is heated above the melting point of the crystal by the first heater, the second heater and the third heater respectively. On the one hand, it can make at least part of the polycrystalline material falling into the tail section fully superheated and have sufficient convection. On the other hand, it can strictly control the temperature of the seed crystal located in the seed crystal section so that its temperature is below the melting point to avoid complete melting of the seed crystal. After the polycrystalline material is completely melted, the growth crucible is rotated again by the rotating shaft so that the melted polycrystalline material falls into the shoulder section and contacts the seed crystal, and crystal growth begins. Due to the sufficient superheating of the polycrystalline material, the polycrystalline material near the seed crystal position has also undergone sufficient superheating convection at this time, which is beneficial to welding with the seed crystal and improves the seeding success rate of growing large-size single crystals by the seeding method. By this method, the success rate of breaking and seeding can also be effectively improved.

[0008] In some possible embodiments, the crystal growth device further includes a first thermocouple and a second thermocouple. The detection end of the first thermocouple is arranged at the end of the seed crystal section close to the shoulder section, and the detection end of the second thermocouple is arranged in the middle of the seed crystal section.

[0009] In a second aspect, the present application example provides a crystal growth method using the crystal growth device in the above embodiment, which includes: first fixing the seed crystal in the seed crystal section of the growth crucible and placing the polycrystalline material in the growth crucible. After sealing, the growth crucible is rotated so that the position of the seed crystal section is higher than that of the tail section, and at least part of the polycrystalline material falls into the tail section. The seed crystal is heated below the melting point of the crystal and the polycrystalline material is heated above the melting point of the crystal by means of zone heating. After the polycrystalline material is completely melted, the growth crucible is rotated again so that the melted polycrystalline material falls into the shoulder section and contacts the seed crystal, and crystal growth begins until the polycrystalline material completes the crystal growth process.

[0010] In the above technical solution, in the crystal growth method of the present application, the seed crystal is first fixed to the seed crystal section, and the growth crucible is rotated so that the seed crystal can still be located in the seed crystal section, while at least part of the polycrystalline material falls into the tail section. By means of zone heating, on the one hand, at least part of the polycrystalline material falling into the tail section can be fully superheated and have sufficient convection, and on the other hand, the temperature of the seed crystal located in the seed crystal section can be strictly controlled to be below the melting point to avoid complete melting of the seed crystal. After the polycrystalline material is completely melted, the growth crucible is rotated again so that the melted polycrystalline material falls into the shoulder section and contacts the seed crystal. Due to the full superheating of the polycrystalline material, the polycrystalline material near the seed crystal position has also undergone sufficient superheating convection, which is conducive to welding with the seed crystal and improving the seeding success rate of obtaining large-size single crystals by the seeding method. The crystal growth method of the present application is applicable to the growth of all types of crystal materials, not limited to a certain material, and has a wide application range, and can solve the problem of insufficient superheating of polycrystalline materials commonly existing in the current seeding method. In addition, when heating up superheatedly, the seed crystal is separated from the polycrystalline material and the position of the seed crystal section is higher than that of the tail section, which can avoid the hydrostatic pressure directly acting on the seed crystal after the melt melts during the superheating process and will not introduce dislocations into the seed crystal.

[0011] In some possible embodiments, after rotating the growth crucible so that the position of the seed crystal section is higher than that of the tail section, the temperatures of the first heater, the second heater, and the third heater are controlled to be T1, T2, and T3 respectively; where T1 = T m - T a , T2 = T m + △T, T3 = T m + △T, T m is the melting point of the crystal, T a is 0 to 10 °C, and △T is the superheat degree.

[0012] In the above technical solution, by controlling the temperatures of the second heater and the third heater to be the sum of the melting point and the superheat degree of the crystal, and controlling the temperature of the first heater to be the difference between the melting point of the crystal and T a , it is possible to not only make the polycrystalline material fully superheated but also avoid complete melting of the seed crystal.

[0013] In some possible embodiments, the superheat degree is 15 °C to 55 °C.

[0014] In the above technical solution, by making the superheat degree within the above range, it is beneficial to make the polycrystalline material fully superheated, completely break the chemical bonds inside the polycrystalline material, make the mixed material uniform, and have sufficient convection.

[0015] In some possible embodiments, after heating the polycrystalline material above the melting point of the crystal, it is kept warm for 80 h.

[0016] In the above technical solution, by keeping the polycrystalline material at a temperature above the melting point for the above-mentioned time, it is beneficial to fully superheat the polycrystalline material, completely break the chemical bonds inside the polycrystalline material, make the mixing uniform, and ensure sufficient convection.

[0017] In some possible implementation schemes, after rotating the growth crucible to make the melted polycrystalline material fall into the shoulder section and contact the seed crystal, the part of the seed crystal in contact with the polycrystalline material is melted by means of zone heating, and after keeping it warm for 10 h to 80 h, crystal growth is started.

[0018] In the above technical solution, in the crystal growth method of the present application, after rotating the growth crucible to make the melted polycrystalline material fall into the shoulder section and contact the seed crystal, the part of the seed crystal in contact with the polycrystalline material is melted by means of zone heating, which can melt the part of the seed crystal in contact with the polycrystalline material, thereby realizing crystal seeding. In addition, keeping warm for the above-mentioned time can make the crystal thermal field conditions fully stable.

[0019] In some possible implementation schemes, a first thermocouple and a second thermocouple are respectively arranged at the end of the seed crystal close to the polycrystalline material and the middle part of the polycrystalline material. When the part of the seed crystal in contact with the polycrystalline material is melted, the temperature of the first thermocouple is made T4 and the temperature of the second thermocouple is made T5 by adjusting the temperatures of the first heater, the second heater, and the third heater; wherein, T m +5 °C ≤ T4 ≤ T m +20 °C, T m -8 °C ≤ T5 ≤ T m +8 °C, T m is the melting point of the crystal.

[0020] In the above technical solution, by adjusting the temperatures of the first heater, the second heater, and the third heater to make the temperatures of the first thermocouple and the second thermocouple within the above ranges, it is beneficial to melt the part of the polycrystalline material in contact with the seed crystal, playing a role in crystal seeding.

[0021] In some possible implementation schemes, the seed crystal is of a boss structure, the seed crystal includes a platform part and a convex part protruding from the platform part, and the seed crystal is matched with the cavity of the boss structure so that the seed crystal is fixed to the seed crystal section.

[0022] In the above technical solution, the seed crystal can be fixedly matched with the inside of the seed crystal section. In addition, the seed crystal of the boss structure is no longer a simple cylindrical shape, and the platform part of the seed crystal has a large heat dissipation area, which can accelerate the heat dissipation of the seed crystal and introduce a large temperature gradient in the seed crystal.

[0023] In some possible implementation schemes, the convex part of the seed crystal is cylindrical, and the diameter of the convex part is 10 mm to 15 mm.

[0024] In the above technical solution, the problem that the polycrystalline material near the seed crystal cannot be fully superheated during melting no longer exists in the crystal growth method of the present application. Therefore, a relatively small seed crystal can be used to grow a single crystal with a larger diameter during crystal seeding, reducing the difficulty and cost of process implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0026] Figure 1 Structural schematic diagram of the crystal growth device according to the embodiment of the present application;

[0027] Figure 2 Structural schematic diagram of the first seed crystal according to the embodiment of the present application;

[0028] Figure 3 Structural schematic diagram of the second seed crystal according to the embodiment of the present application;

[0029] Figure 4 Structural schematic diagram of the growth crucible after rotating 180° according to the embodiment of the present application;

[0030] Figure 5 Structural schematic diagram of the growth crucible after rotating 180° again according to the embodiment of the present application;

[0031] Figure 6 Crystal growth schematic diagram of Comparative Example 1 of the present application;

[0032] Figure 7 Cross-sectional grain diagram of Embodiment 1 of the present application;

[0033] Figure 8 Cross-sectional grain diagram of Embodiment 2 of the present application;

[0034] Figure 9 Cross-sectional grain diagram of Embodiment 3 of the present application;

[0035] Figure 10 Cross-sectional grain diagram of Embodiment 4 of the present application;

[0036] Figure 11 Cross-sectional grain diagram of Embodiment 5 of the present application;

[0037] Figure 12 Cross-sectional grain diagram of Embodiment 6 of the present application;

[0038] Figure 13Cross-sectional grain diagram of Comparative Example 1 of the present application;

[0039] Figure 14 Cross-sectional grain diagram of Comparative Example 2 of the present application;

[0040] Figure 15 Cross-sectional grain diagram of Comparative Example 3 of the present application.

[0041] Icon: 10 - seed crystal; 11 - pedestal part; 12 - convex part; 20 - polycrystalline material; 30 - crystal growth device; 100 - growth crucible; 101 - seed crystal section; 102 - shoulder section; 103 - tail section; 110 - inner growth crucible; 120 - outer growth crucible; 140 - inner growth cap; 150 - sealing plug; 200 - rotating shaft; 310 - first heater; 320 - second heater; 330 - third heater; 400 - bracket; 500 - heat preservation cover; 610 - first thermocouple; 620 - second thermocouple. Detailed implementation manners

[0042] The following will describe the implementation manners of the present application in detail in conjunction with the embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. For those not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified in the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0043] The following specifically describes a crystal growth device and a growth method according to an embodiment of the present application:

[0044] Please refer to Figure 1 , the present application provides a crystal growth device 30, which includes a growth crucible 100, a rotating shaft 200, a first heater 310, a second heater 320, and a third heater 330.

[0045] Among them, the growth crucible 100 includes a seed crystal section 101, a shoulder section 102, and a tail section 103 that extend sequentially along its length direction, and the growth crucible 100 includes an inner growth crucible 110, an outer growth crucible 120, an inner growth cap 140, and a sealing plug 150.

[0046] The inner growth crucible 110 has an open end for placing the seed crystal 10, and an inner growth cap 140 is provided at the open end of the inner growth crucible 110. The outer growth crucible 120 is sleeved outside the inner growth crucible 110, and the sealing plug 150 seals the open end of the outer growth crucible 120.

[0047] The rotating shaft 200 is connected to the shoulder section 102 of the growth crucible 100 and is used for rotating the growth crucible 100 along its radial direction.

[0048] Optionally, the crystal growth apparatus 30 further includes a bracket 400, with one end of each rotating shaft 200 connected to the bracket 400 and the other end also connected to the bracket 400.

[0049] The first heater 310, the second heater 320, and the third heater 330 are respectively used to heat the seed crystal section 101, the shoulder formation section 102, and the tail section 103.

[0050] Optionally, the crystal growth apparatus 30 further includes a heat insulation cover 500, and the growth crucible 100, the first heater 310, the second heater 320, and the third heater 330 are all disposed in the heat insulation cover 500.

[0051] Optionally, the crystal growth apparatus 30 further includes a first thermocouple 610 and a second thermocouple 620. The detection end of the first thermocouple 610 is disposed at the end of the seed crystal section 101 near the shoulder formation section 102, and the detection end of the second thermocouple 620 is disposed in the middle of the seed crystal section 101.

[0052] The crystal growth apparatus 30 of the present application can be used to grow large-sized single crystals. The cavity of the boss structure inside the seed crystal section 101 can fix the seed crystal 10 in the seed crystal section 101 of the growth crucible 100. When heating the polycrystalline material 20, the growth crucible 100 is rotated by the rotating shaft 200, so that the position of the seed crystal section 101 is higher than the position of the tail section 103, and at least part of the polycrystalline material 20 falls into the tail section 103. Further, the first heater 310, the second heater 320, and the third heater 330 respectively heat the seed crystal 10 below the melting point of the crystal and heat the polycrystalline material 20 above the melting point of the crystal. On the one hand, it can make at least part of the polycrystalline material 20 falling into the tail section 103 fully superheated and have sufficient convection. On the other hand, it can strictly control the temperature of the seed crystal 10 located in the seed crystal section 101 to be below the melting point to avoid complete melting of the seed crystal 10. After the polycrystalline material 20 is completely melted, the growth crucible 100 is rotated again by the rotating shaft 200, so that the melted polycrystalline material 20 falls into the shoulder formation section 102 and contacts the seed crystal 10, and crystal growth begins. Due to the sufficient superheating of the polycrystalline material 20, the polycrystalline material 20 near the position of the seed crystal 10 has also undergone sufficient superheating convection, which is beneficial to welding with the seed crystal 10 and improves the success rate of crystal seeding for growing large-sized single crystals by the crystal seeding method.

[0053] The present application also provides a crystal growth method, which includes the following steps:

[0054] S1. Prepare raw materials

[0055] Please refer to Figures 1 - 3 , prepare the seed crystal 10, the polycrystalline material 20, and the growth crucible 100, fix the seed crystal 10 in the seed crystal section 101 of the growth crucible 100, and place the polycrystalline material 20 in the growth crucible 100, and complete the sealing.

[0056] It should be noted that the present application does not limit the way the seed crystal 10 is fixed to the seed crystal section 101 in the growth crucible 100. The following provides a specific implementation manner:

[0057] Please refer to Figure 2 , first process the seed crystal 10 into a boss structure. The seed crystal 10 includes a platform portion 11 and a convex portion 12 protruding from the platform portion 11. Both the convex portion 12 and the platform portion 11 are cylindrical, and the convex portion 12 and the platform portion 11 are concentrically connected. The growth crucible 100 includes an inner growth crucible 110, an outer growth crucible 120, an inner growth cap 140, and a sealing plug 150. The inner growth crucible 110, the outer growth crucible 120, and the inner growth cap 140 can all be made of quartz material. A cavity in the shape of a boss structure is formed inside the seed crystal section 101 of the inner growth crucible 110, and the end of the inner growth crucible 110 for placing the seed crystal 10 is open. First, place the seed crystal 10 into the seed crystal section 101 of the inner growth crucible 110 through the open end of the inner growth crucible 110 (that is, load the seed crystal 10 into the seed crystal section 101 of the inner growth crucible 110 through the lower end of Figure 1 the inner growth crucible 110), and the seed crystal 10 cooperates with the cavity in the shape of a boss structure so that the seed crystal 10 is fixed in the seed crystal section 101. Then, install the inner growth cap 140 at the open end of the inner growth crucible 110. The inner growth cap 140 can prevent the molten polycrystalline material 20 from leaking out from the bottom. Next, sleuth the outer growth crucible 120 outside the inner growth crucible 110, and put the polycrystalline material 20 into the growth crucible 100 through the open end of the outer growth crucible 120 (that is, load the polycrystalline material 20 into the growth crucible 100 through the upper end of Figure 1 the outer growth crucible 120), and finally seal the open end of the outer growth crucible 120 with the sealing plug 150.

[0058] There are the inner growth crucible 110, the outer growth crucible 120, and the inner growth cap 140 at the position of the seed crystal 10, which is equivalent to three layers of crucibles, and can effectively buffer and avoid the transfer of external environmental temperature fluctuations to the seed crystal 10, so that the seed crystal 10 always remains in a stable temperature field environment, which is beneficial to improving the success rate of crystal seeding.

[0059] Through the above placement, not only can the seed crystal 10 be fixed in cooperation with the inside of the seed crystal section 101, but also, the seed crystal 10 with a boss structure is no longer a simple cylinder. The platform portion 11 of the seed crystal 10 has a large heat dissipation area, which can accelerate the heat dissipation of the seed crystal 10 and introduce a large temperature gradient in the seed crystal 10.

[0060] As Figure 3 shown, in addition to the above shape, the seed crystal 10 can also be conical.

[0061] Optionally, the convex portion 12 of the seed crystal 10 is cylindrical, and the diameter of the convex portion 12 is 10 mm to 15 mm.

[0062] As an example, the diameter of the convex portion 12 can be 10 mm, 11 mm, 12 mm, 13 mm, 14 mm or 15 mm.

[0063] With the crystal growth method of the present application, there is no longer a problem that the polycrystalline material 20 near the seed crystal 10 cannot be sufficiently superheated during melting. Therefore, a relatively small seed crystal 10 can be used to grow a single crystal with a larger diameter size by seeding, reducing the difficulty and cost of process implementation.

[0064] S2. Heat the seed crystal 10 and the polycrystalline material 20

[0065] Please refer to Figure 4 , rotate the growth crucible 100 so that the position of the seed crystal section 101 is higher than the position of the tail section 103. The seed crystal 10 remains fixed to the seed crystal section 101, and at least part of the polycrystalline material 20 falls into the tail section 103. Heat the seed crystal 10 below the melting point of the crystal and heat the polycrystalline material 20 above the melting point of the crystal by means of zone heating until the polycrystalline material 20 is completely melted.

[0066] Optionally, a rotating shaft 200 is arranged outside the growth crucible 100, and the growth crucible 100 can be rotated through the rotating shaft 200.

[0067] Optionally, when the starting position of the growth crucible 100 is that the seed crystal section 101 is downward and the tail section 103 is upward, the rotation angle is 180°.

[0068] Optionally, the growth crucible 100 is provided with a first heater 310, a second heater 320 and a third heater 330. The first heater 310, the second heater 320 and the third heater 330 respectively heat the seed crystal section 101, the shoulder-forming section 102 and the tail section 103. After rotating the growth crucible 100 so that the position of the seed crystal section 101 is higher than the position of the tail section 103, control the temperatures of the first heater 310, the second heater 320 and the third heater 330 to be T1, T2 and T3 respectively; where, T1 = T m -T a , T2 = T m +△T, T3 = T m +△T, T m is the melting point of the crystal, T a is 0 to 10 °C, and △T is the superheat degree.

[0069] Among them, the superheat degree is 15 °C to 55 °C.

[0070] As an example, the superheat degree can be 15 °C, 20 °C, 30 °C, 40 °C, 50 °C or 55 °C; T a can be 0, 2 °C, 5 °C, 8 °C or 10 °C.

[0071] By controlling the temperatures of the second heater 320 and the third heater 330 to be the sum of the melting point and the superheat of the crystal, and controlling the temperature of the first heater 310 to be the difference between the melting point of the crystal and T a It can not only make the polycrystalline material 20 fully superheated, which is beneficial to the full superheating of the polycrystalline material 20, the chemical bonds inside the polycrystalline material 20 are completely broken, the mixing is uniform, and the convection is sufficient, but also avoid the complete melting of the seed crystal 10.

[0072] Optionally, after heating the polycrystalline material 20 above the melting point of the crystal, keep it warm for 80 h.

[0073] By keeping the polycrystalline material 20 at a temperature above the melting point for the above time, it is beneficial to make the polycrystalline material 20 fully superheated, the chemical bonds inside the polycrystalline material 20 are completely broken, the mixing is uniform, and the convection is sufficient.

[0074] S3. Crystal seeding

[0075] Please refer to Figure 5 , after the superheating is completed, rotate the growth crucible 100 again so that the melted polycrystalline material 20 falls into the shoulder segment 102 and contacts the seed crystal 10. The part of the seed crystal 10 in contact with the polycrystalline material 20 is melted by means of zone heating, and after keeping it warm for 10 h to 80 h, crystal growth is started until the polycrystalline material 20 completes the crystal growth process.

[0076] A first thermocouple 610 and a second thermocouple 620 are respectively arranged at the end of the seed crystal 10 close to the polycrystalline material 20 and the middle of the polycrystalline material 20. When the part of the seed crystal 10 in contact with the polycrystalline material 20 is melted, by adjusting the temperatures of the first heater 310, the second heater 320, and the third heater 330, the temperature of the first thermocouple 610 is made to be T4, and the temperature of the second thermocouple 620 is made to be T5; where, T m +5 °C ≤ T4 ≤ T m +20 °C, T m -8 °C ≤ T5 ≤ T m +8 °C, T m is the melting point of the crystal.

[0077] By adjusting the temperatures of the first heater 310, the second heater 320, and the third heater 330 so that the temperatures of the first thermocouple 610 and the second thermocouple 620 are within the above ranges, it is beneficial to melt the part of the polycrystalline material 20 in contact with the seed crystal 10 and play a role in crystal seeding.

[0078] As an example, the part of the seed crystal 10 in contact with the polycrystalline material 20 is melted by means of zone heating and kept warm for 10 h, 20 h, 50 h or 80 h.

[0079] After the crystal growth method of the present application rotates the growth crucible 100 to make the melted polycrystalline material 20 fall into the shoulder-forming section 102 and contact the seed crystal 10, the part of the seed crystal 10 in contact with the polycrystalline material 20 is melted by means of zone heating, enabling the part of the seed crystal 10 in contact with the polycrystalline material 20 to melt, thereby achieving crystal seeding. In addition, maintaining the above-mentioned time can fully stabilize the thermal field conditions of the crystal.

[0080] In the crystal growth method of the present application, the seed crystal 10 is first fixed to the seed crystal section 101, and the growth crucible 100 is rotated so that the seed crystal 10 can still be located in the seed crystal section 101, while at least part of the polycrystalline material 20 falls into the tail section 103. By means of zone heating, on the one hand, at least part of the polycrystalline material 20 falling into the tail section 103 can be sufficiently superheated and have sufficient convection, and on the other hand, the temperature of the seed crystal 10 located in the seed crystal section 101 can be strictly controlled to be below the melting point to avoid complete melting of the seed crystal 10. After the polycrystalline material 20 is completely melted, the growth crucible 100 is rotated again to make the melted polycrystalline material 20 fall into the shoulder-forming section 102 and contact the seed crystal 10. Due to the sufficient superheating of the polycrystalline material 20, the polycrystalline material 20 near the position of the seed crystal 10 has also undergone sufficient superheating convection, which is conducive to welding with the seed crystal 10 and improving the crystal seeding success rate of obtaining large-size single crystals by the crystal seeding method. In addition, when heating up superheatedly, the seed crystal 10 is separated from the polycrystalline material 20 and the position of the seed crystal section 101 is higher than the position of the tail section 103, which can avoid the hydrostatic pressure directly applied to the seed crystal 10 after the melt melts during the superheating process and will not introduce dislocations in the seed crystal 10. And because the seed crystal 10 can be separated from the polycrystalline material 20 during superheating, the length of the seed crystal 10 can be made longer so that the length of the seed crystal 10 can be higher than the upper edge of the seed crystal section 101. During the subsequent crystal growth process, part of the seed crystal 10 will penetrate into the melted polycrystalline material 20 for sufficient welding, greatly improving the crystal seeding success rate. The crystal growth method of the present application is applicable to the growth of all types of crystal materials, not limited to a certain material, and has a wide application range, and can solve the problem of insufficient superheating of polycrystalline materials commonly existing in the current crystal seeding method.

[0081] The following further describes in detail a crystal growth device and a growth method of the present application in conjunction with embodiments.

[0082] Embodiment 1

[0083] The embodiment of the present application provides a method for growing a 2-inch cadmium zinc telluride (Cd 0.7 Zn 0.3 Te) crystal, which includes the following steps:

[0084] S1. Prepare raw materials

[0085] Please refer to Figure 1 and 3, prepare a cadmium zinc telluride seed crystal 10, polycrystalline material 20 and a growth crucible 100. The seed crystal 10 is a boss structure. The seed crystal 10 includes a pedestal portion 11 and a convex portion 12 protruding from the pedestal portion 11. Both the convex portion 12 and the pedestal portion 11 are cylindrical, and the convex portion 12 and the pedestal portion 11 are concentrically connected. The diameter of the convex portion 12 is 10 mm. The polycrystalline material 20 includes elemental Te, elemental Zn, and elemental Cd. The growth crucible 100 includes an inner growth crucible 110, an outer growth crucible 120, an inner growth cap 140, and a sealing plug 150. The inner growth crucible 110, the outer growth crucible 120, and the inner growth cap 140 can all be made of quartz. A cavity in the shape of a boss structure is formed inside the seed crystal section 101 of the inner growth crucible 110, and the end of the inner growth crucible 110 for placing the seed crystal 10 is open. First, place the seed crystal 10 through the open end of the inner growth crucible 110 into the seed crystal section 101 of the inner growth crucible 110 (i.e., load the seed crystal 10 into the seed crystal section 101 of the inner growth crucible 110 through the lower end of the inner growth crucible 110 of Figure 1 ). The seed crystal 10 cooperates with the cavity of the boss structure so that the seed crystal 10 is fixed in the seed crystal section 101. Then, install the inner growth cap 140 at the open end of the inner growth crucible 110. The inner growth cap 140 can prevent the molten polycrystalline material 20 from leaking out from the bottom. Next, place the outer growth crucible 120 outside the inner growth crucible 110, and put the polycrystalline material 20 into the growth crucible 100 through the open end of the outer growth crucible 120 (i.e., load the polycrystalline material 20 into the growth crucible 100 through the upper end of the outer growth crucible 120 of Figure 1 ). Finally, seal the open end of the outer growth crucible 120 with the sealing plug 150.

[0086] S2. Heat the seed crystal 10 and the polycrystalline material 20

[0087] Please refer to Figure 4 , rotate the growth crucible 100 by 180° through the rotating shaft 200. The seed crystal 10 remains fixed in the seed crystal section 101, while all the polycrystalline material 20 falls into the tail section 103. Heat the first heater to 1150 °C, the second heater to 1175 °C, and the third heater to 1180 °C. At this time, observe the temperatures of the first thermocouple 610 and the second thermocouple 620 at the seed crystal 10. The temperature of the first thermocouple 610 is 1151 °C, and the temperature of the second thermocouple 620 is 1146 °C. At this time, the temperature of the entire seed crystal 10 is lower than the melting point T of the crystal m . The seed crystal 10 will not melt, while the polycrystalline material 20 located in the tail section 103 of the growth crucible 100 can be fully melted under superheat. Keep it warm for 80 h, and the polycrystalline material 20 is fully mixed and homogenized.

[0088] S3. Crystal seeding

[0089] Please refer to Figure 5, after the overheating ends, rotate the growth crucible 100 by 180° again through the rotating shaft 200, so that the polycrystalline material 20 after melting and sufficient overheating falls into the shoulder section 102 and contacts the seed crystal 10. Heat the first heater to 1160°C, heat the second heater to 1165°C, and keep the temperature of the third heater at 1170°C. At this time, observe the temperatures of the first thermocouple 610 and the second thermocouple 620 at the seed crystal 10. The temperature of the first thermocouple 610 is 1162°C, and the temperature of the second thermocouple 620 is 1156°C. After heat preservation for 80 hours, start crystal growth until the polycrystalline material 20 completes the crystal growth process.

[0090] Example 2

[0091] An embodiment of the present application provides a method for growing a 4-inch cadmium zinc telluride (Cd 0.7 Zn 0.3 Te) crystal, which includes the following steps:

[0092] S1. Prepare raw materials

[0093] Please refer to Figure 1 and 3 , prepare a cadmium zinc telluride seed crystal 10, a polycrystalline material 20 and a growth crucible 100. The seed crystal 10 is a boss structure. The seed crystal 10 includes a platform part 11 and a convex part 12 protruding from the platform part 11. Both the convex part 12 and the platform part 11 are cylindrical, and the convex part 12 and the platform part 11 are concentrically connected. The diameter of the convex part 12 is 10 mm. The polycrystalline material 20 includes elemental Te, elemental Zn and elemental Cd. The growth crucible 100 includes an inner growth crucible 110, an outer growth crucible 120, an inner growth cap 140 and a sealing plug 150. The inner growth crucible 110, the outer growth crucible 120 and the inner growth cap 140 can all be made of quartz. A cavity with a boss structure is formed inside the seed crystal section 101 of the inner growth crucible 110, and the end of the inner growth crucible 110 for placing the seed crystal 10 is open. First, place the seed crystal 10 into the seed crystal section 101 of the inner growth crucible 110 through the open end of the inner growth crucible 110 (that is, load the seed crystal 10 into the seed crystal section 101 of the inner growth crucible 110 through the lower end of the Figure 1 inner growth crucible 110). The seed crystal 10 cooperates with the cavity of the boss structure so that the seed crystal 10 is fixed in the seed crystal section 101. Then, install the inner growth cap 140 at the open end of the inner growth crucible 110. The inner growth cap 140 can prevent the melted polycrystalline material 20 from leaking out from the bottom. Then, sleeved the outer growth crucible 120 outside the inner growth crucible 110, and put the polycrystalline material 20 into the growth crucible 100 through the open end of the outer growth crucible 120 (that is, load the polycrystalline material 20 into the growth crucible 100 through the upper end of the Figure 1 outer growth crucible 120). Finally, seal the open end of the outer growth crucible 120 with the sealing plug 150.

[0094] S2. Heat the seed crystal 10 and the polycrystalline material 20

[0095] Please refer to Figure 4 , rotate the growth crucible 100 by 180° through the rotating shaft 200. The seed crystal 10 remains fixed to the seed crystal section 101, while all the polycrystalline material 20 falls into the tail section 103. Heat the first heater to 1150°C, the second heater to 1180°C, and the third heater to 1185°C. At this time, observe the temperatures of the first thermocouple 610 and the second thermocouple 620 at the seed crystal 10. The temperature of the first thermocouple 610 is 1152°C, and the temperature of the second thermocouple 620 is 1146°C. At this time, the temperature of the entire seed crystal 10 is lower than the melting point T of the crystal m , the seed crystal 10 will not melt, and the polycrystalline material 20 located in the tail section 103 of the growth crucible 100 can be fully melted under superheat. Keep it warm for 80 h, and the polycrystalline material 20 is fully mixed and homogenized.

[0096] S3. Crystal seeding

[0097] Please refer to Figure 5 , after the superheat ends, rotate the growth crucible 100 by 180° again through the rotating shaft 200, so that the melted and fully superheated polycrystalline material 20 falls into the shoulder section 102 and contacts the seed crystal 10. Heat the first heater to 1160°C, the second heater to 1170°C, and keep the temperature of the third heater at 1175°C. At this time, observe the temperatures of the first thermocouple 610 and the second thermocouple 620 at the seed crystal 10. The temperature of the first thermocouple 610 is 1163°C, and the temperature of the second thermocouple 620 is 1156°C. After keeping it warm for 10 h, start crystal growth until the polycrystalline material 20 completes the crystal growth process.

[0098] Example 3

[0099] This application provides a method for growing a 2-inch cadmium zinc telluride (Cd 0.7 Zn 0.3 Te) crystal. On the basis of Example 2, change the heat preservation time in step S3 to 40 h, and keep other parameters unchanged.

[0100] Example 4

[0101] This application provides a method for growing a 2-inch cadmium zinc telluride (Cd 0.7 Zn 0.3 Te) crystal. On the basis of Example 1, change the heating temperature of the first heater in step S2 to 1150°C, the heating temperature of the second heater to 1185°C, and the heating temperature of the third heater to 1190°C, and keep other parameters unchanged.

[0102] Example 5

[0103] An embodiment of the present application provides a method for growing a 2-inch cadmium zinc telluride (Cd 0.7 Zn 0.3 Te) crystal. Based on Example 1, the heating temperature of the first heater in step S2 is changed to 1150 °C, the heating temperature of the second heater is changed to 1190 °C, and the heating temperature of the third heater is changed to 1195 °C, with other conditions remaining unchanged.

[0104] Example 6

[0105] An embodiment of the present application provides a method for growing a 2-inch CdMnTe. The method includes the following steps:

[0106] S1. Prepare raw materials

[0107] Please refer to Figure 1 and 3 , a CdMnTe seed crystal 10, polycrystalline material 20, and a growth crucible 100 are provided. The seed crystal 10 has a boss structure. The seed crystal 10 includes a pedestal portion 11 and a convex portion 12 protruding from the pedestal portion 11. Both the convex portion 12 and the pedestal portion 11 are cylindrical and are concentrically connected. The diameter of the convex portion 12 is 10 mm. The polycrystalline material 20 includes CdMnTe. The growth crucible 100 includes an inner growth crucible 110, an outer growth crucible 120, an inner growth cap 140, and a sealing plug 150. The inner growth crucible 110, the outer growth crucible 120, and the inner growth cap 140 can all be made of quartz. A cavity with a boss structure is formed inside the seed crystal section 101 of the inner growth crucible 110, and the end of the inner growth crucible 110 for placing the seed crystal 10 is open. First, the seed crystal 10 is placed into the seed crystal section 101 of the inner growth crucible 110 through the open end of the inner growth crucible 110 (i.e., the seed crystal 10 is loaded into the seed crystal section 101 of the inner growth crucible 110 through the lower end of the inner growth crucible 110 of Figure 1 ). The seed crystal 10 cooperates with the cavity of the boss structure so that the seed crystal 10 is fixed in the seed crystal section 101. Then, the inner growth cap 140 is installed at the open end of the inner growth crucible 110. The inner growth cap 140 can prevent the molten polycrystalline material 20 from leaking out from the bottom. Then, the outer growth crucible 120 is sleeved outside the inner growth crucible 110. The polycrystalline material 20 is put into the growth crucible 100 through the open end of the outer growth crucible 120 (i.e., the polycrystalline material 20 is loaded into the growth crucible 100 through the upper end of the outer growth crucible 120 of Figure 1 ), and finally, the open end of the outer growth crucible 120 is sealed with the sealing plug 150.

[0108] S2. Heat the seed crystal 10 and the polycrystalline material 20

[0109] Please refer to Figure 4, rotate the growth crucible 100 by 180° through the rotating shaft 200. The seed crystal 10 remains fixed to the seed crystal section 101, while all the polycrystalline material 20 falls into the tail section 103. Heat the first heater to 1040 °C, the second heater to 1080 °C, and the third heater to 1085 °C. At this time, observe the temperatures of the first thermocouple 610 and the second thermocouple 620 at the seed crystal 10. The temperature of the first thermocouple 610 is 1045 °C, and the temperature of the second thermocouple 620 is 1038 °C. At this time, the temperature of the entire seed crystal 10 is lower than the melting point T of the crystal m , the seed crystal 10 will not melt, while the polycrystalline material 20 located in the tail section 103 of the growth crucible 100 can be fully melted under superheat. Keep it warm for 70 h, and the polycrystalline material 20 is fully mixed and homogenized.

[0110] S3. Crystal seeding

[0111] Please refer to Figure 5 , after the superheat ends, rotate the growth crucible 100 by 180° again through the rotating shaft 200, so that the melted and fully superheated polycrystalline material 20 falls into the shoulder section 102 and contacts the seed crystal 10. Heat the first heater to 1050 °C, the second heater to 1070 °C, and keep the temperature of the third heater at 1080 °C. At this time, observe the temperatures of the first thermocouple 610 and the second thermocouple 620 at the seed crystal 10. The temperature of the first thermocouple 610 is 1055 °C, and the temperature of the second thermocouple 620 is 1048 °C. After keeping it warm for 70 h, start crystal growth until the polycrystalline material 20 completes the crystal growth process.

[0112] Comparative Example 1

[0113] The comparative example of this application provides a method for growing a 2-inch cadmium zinc telluride (Cd 0.7 Zn 0.3 Te) crystal, which includes the following steps:

[0114] S1. Prepare raw materials

[0115] Please refer to Figure 6 , prepare a cadmium zinc telluride seed crystal 10, polycrystalline material 20 and growth crucible 100. The seed crystal 10 is cylindrical with a diameter of 10 mm. The polycrystalline material 20 includes elemental Te, elemental Zn and elemental Cd. First, place the seed crystal 10 in the seed crystal section 101 of the growth crucible 100, then place the polycrystalline material 20 in the growth crucible 100, and finally use the sealing plug 150 to seal the open end of the growth crucible 100.

[0116] S2. Heat the seed crystal 10 and the polycrystalline material 20

[0117] Heat the first heater to 1160 °C, the second heater to 1165 °C, and keep the temperature of the third heater at 1170 °C. At this time, observe the temperatures of the first thermocouple 610 and the second thermocouple 620 at the seed crystal 10. The temperature of the first thermocouple 610 is 1162 °C, and the temperature of the second thermocouple 620 is 1156 °C. Keep the temperature for 80 h.

[0118] S3. Crystal seeding

[0119] After the melting of the polycrystalline material 20 is completed, heat the first heater to 1160 °C, the second heater to 1165 °C, and keep the temperature of the third heater at 1170 °C. At this time, observe the temperatures of the first thermocouple 610 and the second thermocouple 620 at the seed crystal 10. The temperature of the first thermocouple 610 is 1162 °C, and the temperature of the second thermocouple 620 is 1156 °C. After keeping the temperature for 80 h, start crystal growth until the polycrystalline material 20 completes the crystal growth process.

[0120] Comparative example 2

[0121] The comparative example of the present application provides a method for growing a 4-inch cadmium zinc telluride (Cd 0.7 Zn 0.3 Te) crystal, which includes the following steps:

[0122] S1. Prepare raw materials

[0123] Please refer to Figure 6 , prepare a cadmium zinc telluride seed crystal 10, a polycrystalline material 20 and a growth crucible 100. The seed crystal 10 is cylindrical with a diameter of 10 mm. The polycrystalline material 20 includes elemental Te, elemental Zn and elemental Cd. First, place the seed crystal 10 in the seed crystal section 101 of the growth crucible 100, then place the polycrystalline material 20 in the growth crucible 100, and finally seal the open end of the growth crucible 100 with a sealing plug 150.

[0124] S2. Heat the seed crystal 10 and the polycrystalline material 20

[0125] Heat the first heater to 1160 °C, the second heater to 1170 °C, and keep the temperature of the third heater at 1175 °C. At this time, observe the temperatures of the first thermocouple 610 and the second thermocouple 620 at the seed crystal 10. The temperature of the first thermocouple 610 is 1163 °C, and the temperature of the second thermocouple 620 is 1156 °C. Keep the temperature for 80 h.

[0126] S3. Crystal seeding

[0127] After the polycrystalline material 20 is melted, the No. 1 heater is heated to 1160°C, the No. 2 heater is heated to 1170°C, and the temperature of the No. 3 heater is maintained at 1175°C. At this time, the temperatures of the first thermocouple 610 and the second thermocouple 620 of the seed crystal 10 are observed. The temperature of the first thermocouple 610 is 1163°C, and the temperature of the second thermocouple 620 is 1156°C. After keeping warm for 80 hours, crystal growth begins until the polycrystalline material 20 completes the crystal growth process.

[0128] Comparative Example 3

[0129] The comparative example of the present application provides a 2-inch CdMnTe crystal growth method, which comprises the following steps:

[0130] S1. Prepare raw materials

[0131] See also Figure 6 , prepare CdMnTe seed crystal 10, polycrystalline material 20 and growth crucible 100, the seed crystal 10 is cylindrical with a diameter of 10 mm, and the polycrystalline material 20 includes CdMnTe. First, the seed crystal 10 is placed in the seed crystal section 101 of the growth crucible 100, and then the polycrystalline material 20 is placed in the growth crucible 100, and finally the opening of the growth crucible 100 is sealed with a sealing plug 150.

[0132] S2, heating the seed crystal 10 and the polycrystalline material 20

[0133] Heat heater No. 1 to 1050°C, heater No. 2 to 1070°C, and keep heater No. 3 at 1080°C. Observe the temperatures of the first thermocouple 610 and the second thermocouple 620 of the seed crystal 10. The temperature of the first thermocouple 610 is 1055°C, and the temperature of the second thermocouple 620 is 1048°C. Keep the temperature for 70 hours.

[0134] S3, seeding

[0135] After the polycrystalline material 20 is melted, the No. 1 heater is heated to 1050°C, the No. 2 heater is heated to 1070°C, and the temperature of the No. 3 heater is maintained at 1080°C. At this time, the temperatures of the first thermocouple 610 and the second thermocouple 620 of the seed crystal 10 are observed. The temperature of the first thermocouple 610 is 1055°C, and the temperature of the second thermocouple 620 is 1048°C. After keeping warm for 70 hours, crystal growth begins until the polycrystalline material 20 completes the crystal growth process.

[0136] Test example

[0137] Take out the crystals obtained in Examples 1 to 6 and Comparative Examples 1 to 3, and cut the crystals along the crystal axis to visually see the distribution of the crystal grains, such as Figures 7 - 15 shown.

[0138] It can be seen from the results of slicing the grains that, using the traditional method, for the crystals in Comparative Examples 1 to 3, due to insufficient overheating, the polycrystalline materials could not be completely melted, and the final grown grain results were poor, all being granular miscellaneous crystals. In Examples 1 to 6, the crystal growth overheating method of the present application was adopted, and the grown grain results were better. It can also be seen from the results of Example 1, Example 3 and Example 4 that as the overheating temperature gradually increases, the grown crystal grains become better. For the crystal in Example 4, except for a small piece of miscellaneous crystal at the tail, the rest is close to a single crystal.

[0139] The above are only specific embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A crystal growth apparatus, characterized in that, The crystal growth device includes a growth crucible, a rotating shaft, a first heater, a second heater, and a third heater. The growth crucible includes a seed crystal section, a shoulder section, and a tail section that extend sequentially along its length direction. The interior of the seed crystal section is formed into a cavity with a boss structure. The rotating shaft is connected to the shoulder section of the growth crucible and is used to rotate the growth crucible radially. The first heater, the second heater, and the third heater are respectively used to heat the seed crystal section, the shoulder section, and the tail section.

2. The crystal growth apparatus according to claim 1, wherein The crystal growth device further includes a first thermocouple and a second thermocouple. The detection end of the first thermocouple is arranged at the end of the seed crystal section close to the shoulder section, and the detection end of the second thermocouple is arranged in the middle of the seed crystal section.

3. A crystal growth method using the crystal growth apparatus according to claim 1, characterized in that, The crystal growth method includes: first fixing a seed crystal in the seed crystal section of the growth crucible and placing polycrystalline material in the growth crucible. After sealing, rotate the growth crucible so that the position of the seed crystal section is higher than the position of the tail section, and at least part of the polycrystalline material falls into the tail section. Heat the seed crystal below the melting point of the crystal and heat the polycrystalline material above the melting point of the crystal by means of zone heating. After the polycrystalline material is completely melted, rotate the growth crucible again so that the melted polycrystalline material falls into the shoulder section and contacts the seed crystal, and start crystal growth until the polycrystalline material completes the crystal growth process.

4. The crystal growth method according to claim 3, characterized in that, After rotating the growth crucible so that the position of the seed crystal section is higher than the position of the tail section, control the temperatures of the first heater, the second heater, and the third heater to be T1, T2, and T3 respectively; Among them, T1 = T m - T a , T2 = T m + △T, T3 = T m + △T, T m is the melting point of the crystal, T a is 0 to 10 °C, and △T is the degree of superheat.

5. The crystal growth method according to claim 4, wherein, The superheat degree is 15°C to 55°C.

6. The crystal growth method according to claim 3, wherein, After heating the polycrystalline material above the melting point of the crystal, keep it warm for 80 h.

7. The crystal growth method according to claim 3, characterized in that, After rotating the growth crucible so that the melted polycrystalline material falls into the shoulder section and contacts the seed crystal, melt the part where the seed crystal contacts the polycrystalline material by means of zone heating, and after keeping it warm for 10 h to 80 h, start crystal growth again.

8. The crystal growth method according to claim 7, wherein A first thermocouple and a second thermocouple are respectively arranged at the end of the seed crystal close to the polycrystalline material and in the middle of the polycrystalline material. When the part where the seed crystal contacts the polycrystalline material is melted, adjust the temperatures of the first heater, the second heater, and the third heater so that the temperature of the first thermocouple is T4 and the temperature of the second thermocouple is T5; Among them, T m +5°C ≤ T4 ≤ T m +20°C, T m -8°C ≤ T5 ≤ T m +8°C, T m is the melting point of the crystal.

9. The crystal growth method according to claim 3, wherein The seed crystal has a boss structure. The seed crystal includes a platform part and a convex part protruding from the platform part. The seed crystal is matched with the cavity of the boss structure so that the seed crystal is fixed in the seed crystal section.

10. The crystal growth method according to claim 9, characterized in that, The convex part of the seed crystal is cylindrical, and the diameter of the convex part is 10 mm to 15 mm.

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