Crystal growth method and growth device

Abstract

The invention provides a crystal growth method and device, and belongs to the technical field of crystal growth. The crystal growth method comprises the following steps: placing a seed crystal and a polycrystalline material block in a growth tube, sealing a tube opening of the growth tube in a manner that the end part of a heat conduction plug is inserted into a first blind hole of the polycrystalline material block, heating the growth tube until the polycrystalline material block is molten, cooling and stopping growth when the seed crystal begins to grow until a crystal growth interface is close to the bottom of a heat conduction section, and then replacing the heat conduction plug with the sealing plug, and heating the growth tube again by taking the position where crystal growth is stopped as a crystal growth starting point for heating and crystal growth until the crystal growth process of the polycrystal material block is completed. According to the application, the heat conduction plug is matched with the first blind hole of the polycrystal material block, and the heat conduction plug can timely conduct out heat in the center of the melt formed by partially melting the polycrystal material block in the seeding and shouldering stages, so that the solid-liquid interface of the polycrystal material block is always kept as a convex interface; the smooth seeding is facilitated; and the single crystal can be directly obtained through seeding and shouldering stages.

Description

Technical Field

[0001] The present application relates to the technical field of crystal growth, and in particular to a crystal growth method and a growth device. Background Art

[0002] At present, most semiconductor crystals have the problem of low thermal conductivity, which makes it difficult to prepare large-sized single crystals. In addition, seed crystals need to be used for seeding to grow single crystals. Generally, the larger the seed crystal diameter and the longer the seed crystal length, the easier it is to produce single crystals. However, due to the difficulty in growing single crystals, the preparation of large-sized seed crystals is also difficult. In addition, a large number of polycrystals and impurities are likely to appear during the seeding and shouldering stages, resulting in the grains still being messy when transitioning to the equal-diameter growth stage, making it difficult to grow single crystals, which greatly reduces the finished product rate and yield rate. Summary of the invention

[0003] The present application provides a crystal growth method and a growth device, which can improve the problem that low thermal conductivity crystals are difficult to seed successfully and single crystal growth is difficult.

[0004] The embodiment of the present application is implemented as follows: In a first aspect, the present application example provides a crystal growth method, which includes: first placing a seed crystal at the bottom of a growth tube and placing a polycrystalline block in the growth tube, the polycrystalline block having a first blind hole located in the middle and facing upward, and using a heat-conducting plug to seal the tube mouth of the growth tube, the heat-conducting plug including a heat-conducting section filled with a heat-conducting material, the heat-conducting section being inserted into the first blind hole and cooperating with the first blind hole, and then heating the growth tube until the polycrystalline block is melted, and when the seed crystal starts to grow until the distance between the crystal growth interface and the bottom of the heat-conducting section is 1mm~10mm, the growth is stopped by cooling down, and then replacing the heat-conducting plug with a sealing plug, and using the position where the crystal growth is stopped as the starting point of the crystal growth, and heating the growth tube again to increase the temperature and grow the crystal until the polycrystalline block completes the crystal growth process.

[0005] In the above technical scheme, the crystal growth method of the present application first cooperates with a heat-conducting plug having a heat-conducting section through a polycrystalline block having a first blind hole. Since the heat-conducting material is filled inside the heat-conducting section, the heat-conducting section has a large thermal conductivity, and the heat of the melt center formed by partial melting of the polycrystalline block can be timely extracted in the seeding and shouldering stages. On the same horizontal plane, the temperature of the melt center will be lower than the surrounding area. At this time, a convex isothermal surface will be formed in the melt, thereby ensuring that the solid-liquid interface of the polycrystalline block is always maintained as a convex interface, which is conducive to smooth seeding and can directly obtain a single crystal through the seeding and shouldering stages. Finally, after replacing the heat-conducting plug with a sealing plug, the entire crystal growth process is completed to obtain a large-sized single crystal. In addition, in the initial stage of crystal growth, the heat-conducting section can improve the thermal uniformity inside the melt, so that the temperature field inside the crystal is highly symmetrical, which is conducive to improving the uniformity of the crystal. And the crystal growth method of the present application is simple to operate, low in cost, and highly portable. It is theoretically applicable to all types of crystal growth, especially crystal growth with low thermal conductivity.

[0006] In some possible implementation schemes, the polycrystalline block includes a blind hole segment and a support segment extending sequentially along the length direction, the first blind hole is located in the blind hole segment, and the volume ratio of the blind hole segment to the support segment is 4:1-8:1.

[0007] In the above technical solution, by making the volume ratio of the blind hole section and the support section within the above range, it is beneficial to smoothly seed the crystal and directly obtain the single crystal in the seeding and shoulder release stages, and subsequently complete the entire crystal growth process to obtain a large-size single crystal.

[0008] In some possible implementation schemes, the polycrystalline block is a cylinder, and the ratio of the outer diameter of the polycrystalline block to the inner diameter of the first blind hole is 2:1-3:1.

[0009] In the above technical solution, by making the ratio of the outer diameter of the polycrystalline block to the inner diameter of the first blind hole within the above range, it is not only beneficial for the heat-conducting section inserted into the first blind hole to fully extract the heat from the center of the melt formed by the partial melting of the polycrystalline block, but also the temperature of the center of the melt will be lower than that of the surrounding on the same horizontal plane. At this time, a convex isothermal surface will be formed in the melt, thereby ensuring that the solid-liquid interface of the polycrystalline block always remains a convex interface, and a larger single crystal can be obtained in a shorter growth tube.

[0010] In some possible embodiments, the polycrystalline block is prepared by the following method: First, place the single-element raw material in a mixing tube, and use a boss plug to seal the tube mouth of the mixing tube. The boss plug includes an annular boss and a second blind hole located in the middle. Then, heat the mixing tube until the single-element raw material is completely melted to obtain liquid raw material. Then, rotate the mixing tube so that the boss plug faces downward, and the liquid raw material fills the annular boss. Finally, cool the liquid raw material to solidify to form a polycrystalline block.

[0011] In the above technical scheme, the present application first heats and melts the single-element raw material to obtain a liquid raw material, and then rotates the mixing tube to allow the liquid raw material to flow into and fill the annular boss. After solidification, part of the liquid raw material that flows into the annular boss forms a structure with a first blind hole in the middle.

[0012] In some possible implementations, the growth tube includes a seed crystal segment, a shoulder segment and an equal diameter segment extending in sequence along the length direction, the seed crystal is arranged in the seed crystal segment, and the distance between the bottom of the heat conduction segment and the top of the shoulder segment is 15mm~20mm.

[0013] In the above technical solution, by making the distance between the bottom of the heat conduction section and the top of the shoulder release section within the above range, the heat conduction section can penetrate into the center of the melt formed by partial melting of the polycrystalline block, and the heat conduction section is closer to the seed crystal and the shoulder release position, and has a better heat conduction effect.

[0014] In some possible implementation schemes, the seed crystal segment and the equal-diameter segment are both cylinders, and the inner diameter ratio of the seed crystal segment to the equal-diameter segment is 1:5-1:20.

[0015] In the above technical solution, by making the inner diameter ratio of the seed crystal segment and the equal diameter segment within the above range, a smaller sized seed crystal can be used to form a larger sized single crystal, which is conducive to lowering the difficulty of seed crystal preparation and reducing production costs.

[0016] In some possible implementation schemes, when replacing the heat conductive plug with a sealing plug, the heat conductive plug is first removed, and then the single substance raw material is added to the growth tube, and then the sealing plug is used to seal the tube opening of the growth tube.

[0017] In the above technical solution, when performing the secondary sealing of the tube mouth, the present application can add single-element raw materials into the growth tube again, thereby effectively increasing the length of the growing crystal and improving the crystal growth efficiency.

[0018] In some possible implementation schemes, the heat-conducting plug further includes a groove located on the outer wall, and the position of the groove corresponds to the heat-conducting plug.

[0019] In the above technical solution, when using a sealing plug to replace the thermal plug, you can directly use a tool to gently lift up the groove, thereby separating the upper and lower parts of the growth tube located in the outer wall groove, quickly remove the thermal plug and install the sealing plug. This disassembly method does not require the use of a cutting machine to break the tube, and the inside of the tube can still be kept clean, so the same growth tube can be used for continued growth.

[0020] In some possible embodiments, the thermally conductive material includes silicon carbide.

[0021] In the above technical solution, silicon carbide has a large thermal conductivity and can promptly remove the heat from the center of the melt formed by partial melting of the polycrystalline block during the seeding and shouldering stages. On the same horizontal plane, the temperature of the center of the melt will be lower than the surrounding area. At this time, a convex isothermal surface will be formed in the melt, thereby ensuring that the solid-liquid interface of the polycrystalline block always remains a convex interface.

[0022] In the second aspect, the present application provides an example of a crystal growth device used in the crystal growth method of the above-mentioned embodiment, which includes a growth tube, a heat conductive plug, a sealing plug, a seed crystal and a polycrystalline block, wherein the heat conductive plug and the sealing plug are used to seal the tube mouth of the growth tube respectively, wherein the heat conductive plug includes a heat conductive section filled with a heat conductive material, the seed crystal is arranged at the bottom of the growth tube, the polycrystalline block is arranged in the growth tube, and the polycrystalline block has a first blind hole located in the middle and facing upward, and the first blind hole and the heat conductive section cooperate.

[0023] In the above technical scheme, the crystal growth device of the present application can be used to grow large-sized single crystals. During the crystal growth process, the polycrystalline block with the first blind hole cooperates with the heat-conducting plug with the heat-conducting section. Since the heat-conducting material is filled inside the heat-conducting section, the heat-conducting section has a large thermal conductivity, and can timely extract the heat from the center of the melt formed by partial melting of the polycrystalline block in the seeding and shouldering stages. On the same horizontal plane, the temperature of the melt center will be lower than that of the surroundings. At this time, a convex isothermal surface will be formed in the melt, thereby ensuring that the solid-liquid interface of the polycrystalline block always remains a convex interface, which is conducive to smooth seeding and direct acquisition of single crystals through the seeding and shouldering stages. Finally, after replacing the heat-conducting plug with a sealing plug, the entire crystal growth process is completed to obtain a large-sized single crystal. In addition, in the initial stage of crystal growth, the heat-conducting section can improve the thermal uniformity inside the melt, so that the temperature field inside the crystal is highly symmetrical, which is conducive to improving the uniformity of the crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a schematic diagram of a mixing tube with the nozzle facing upward when preparing a polycrystalline block in an embodiment of the present application; Figure 2 This is a schematic diagram of a mixing tube with the nozzle facing downward when preparing a polycrystalline block in an embodiment of the present application; Figure 3 A front view of a polycrystalline block according to an embodiment of the present application; Figure 4 A top view of a polycrystalline block according to an embodiment of the present application; Figure 5 A schematic diagram of the cooperation between the growth tube and the heat-conducting plug in the crystal growth device of the embodiment of the present application; Figure 6 This is a schematic diagram of the cooperation between the growth tube and the heat-conducting plug during the seeding process in the embodiment of the present application; Figure 7 It is a schematic diagram of the cooperation between the growth tube and the sealing plug in the crystal growth device of the embodiment of the present application; Figure 8 This is a schematic diagram of a polycrystalline block when crystal growth is completed in an embodiment of the present application; Fig. 9 This is a schematic diagram of preparing a polycrystalline block in a comparative example of the present application; Fig.10 This is a schematic diagram of seeding in the comparative example of the present application; Fig.11 A grain distribution photograph of a cross section of the crystal prepared in Example 1 of the present application along the axis; Fig.12 This is a grain distribution photograph of a cross section of a crystal along the axis obtained in Comparative Example 1 of the present application; Fig.13 A photograph of the grain distribution of the cross section of the crystal along the axis obtained in Example 2 of the present application; Fig.14 This is a grain distribution photograph of the cross section along the axis of the crystal prepared in Comparative Example 2 of the present application.

[0026] Icons: 10-crystal growth device; 100-combination tube; 110-boss plug; 111-annular boss; 112-second blind hole; 120-single-element raw material; 200-polycrystalline block; 210-blind hole section; 211-first blind hole; 220-support section; 300-growth tube; 301-seed crystal section; 302-shoulder section; 303-equal diameter section; 310-thermal plug; 311-thermal conductive section; 312-thermal conductive material; 313-boss section; 314-groove; 320-sealing plug; 400-seed crystal; 500-melt; 600-solid-liquid interface. DETAILED DESCRIPTION

[0027] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0028] The present application finds that during the crystal growth process, especially in the seeding and shouldering stages, due to the low thermal conductivity of the crystal, the heat inside the melt formed by the melting of the polycrystalline material cannot be discharged in time, resulting in a serious depression in the isothermal surface at the solid-liquid interface of the polycrystalline material, namely a concave growth interface. In the case of a concave growth interface, a large number of polycrystalline and miscellaneous crystals are likely to appear in the seeding and shouldering stages, resulting in the grains still being messy when transitioning to the equal-diameter growth stage, making it difficult to grow single crystals, greatly reducing the finished product rate and yield.

[0029] Based on this, the present application provides a crystal growth method, which comprises the following steps: S1. Preparation of polycrystalline blocks See also Figure 1 and 2 First, make the mouth of the combining tube 100 face upward, place the single-element raw material 120 in the combining tube 100, and use the boss plug 110 to seal the mouth of the combining tube 100, wherein the boss plug 110 includes an annular boss 111 and a second blind hole 112 located in the middle, and when the mouth of the combining tube 100 faces upward, the second blind hole 112 also faces upward; then heat the combining tube 100 until the single-element raw material 120 is completely melted to obtain liquid raw material, and then rotate the combining tube 100 to make the boss plug 110 face downward, at this time the second blind hole 112 also faces downward, and the liquid raw material fills the annular boss 111, and finally cool the liquid raw material to solidify to form a polycrystalline block 200.

[0030] Optionally, the single element raw material 120 includes bulk polycrystalline single element raw material 120 .

[0031] Optionally, the combining tube 100 is heated in a combining furnace.

[0032] See also Figure 3 The obtained polycrystalline block 200 includes a blind hole section 210 and a support section 220 extending in sequence along the length direction. The first blind hole 211 is located in the blind hole section 210 and in the middle of the cross section of the blind hole section 210 .

[0033] Optionally, the volume ratio of the blind hole section 210 to the support section 220 is 4:1-8:1.

[0034] As an example, the volume ratio of the blind hole segment 210 to the support segment 220 may be 4:1, 5:1, 6:1, 7:1, or 8:1.

[0035] By making the volume ratio of the blind hole section 210 and the support section 220 within the above range, it is beneficial to smoothly seed the crystal in the seeding and shoulder release stages and directly obtain a single crystal, and subsequently complete the entire crystal growth process to obtain a large-sized single crystal.

[0036] It should be noted that when the cross section of the combined material tube 100 is circular, the obtained polycrystalline material block 200 is cylindrical as a whole, and the first blind holes 211 are distributed along the axial direction of the polycrystalline material block 200 .

[0037] Optionally, the ratio of the outer diameter of the polycrystalline block 200 to the inner diameter of the first blind hole 211 is 2:1-3:1.

[0038] As an example, the ratio of the outer diameter of the polycrystalline block 200 to the inner diameter of the first blind hole 211 may be 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1 or 3:1.

[0039] By making the ratio of the outer diameter of the polycrystalline block 200 to the inner diameter of the first blind hole 211 within the above range, it is not only beneficial for the heat conductive section 311 inserted into the first blind hole 211 to fully extract the heat from the center of the melt 500 formed by the partial melting of the polycrystalline block 200, but also the temperature of the center of the melt 500 will be lower than that of the surrounding on the same horizontal plane. At this time, a convex isothermal surface will be formed in the melt 500, thereby ensuring that the solid-liquid interface 600 of the polycrystalline block 200 always remains a convex interface, and a larger single crystal can be obtained in a shorter growth tube 300.

[0040] In the present application, the single substance raw material 120 is first heated and melted to obtain a liquid raw material, and then the liquid raw material is allowed to flow into and fill the annular boss 111 by rotating the mixing tube 100. After solidification, part of the liquid raw material that flows into the annular boss 111 forms a structure with a first blind hole 211 in the middle.

[0041] S2, seeding See also Figure 4 and 5, take out the growth tube 300 so that the tube mouth of the growth tube 300 faces upward, the growth tube 300 includes a seed crystal segment 301, a shoulder segment 302 and an equal diameter segment 303 extending in sequence along the length direction, first place the seed crystal 400 in the seed crystal segment 301, and then place the prepared polycrystalline material block 200 in the growth tube 300 with the first blind hole 211 facing upward, and use a heat conductive plug 310 to seal the tube mouth of the growth tube 300, wherein the heat conductive plug 310 includes a heat conductive segment 311, the heat conductive segment 311 is inserted into the first blind hole 211 and cooperates with the first blind hole 211, and fills the interior of the heat conductive segment 311 The growth tube 300 is heated until the polycrystalline block 200 partially melts to form a melt 500, and the melt 500 contacts the heat conducting section 311. Since the heat conducting section 311 is filled with the heat conducting material 312, it will conduct the heat from the center of the melt 500 at a very fast speed. On the same horizontal plane, the temperature at the center of the melt 500 will be lower than the surrounding temperature. At this time, a convex isothermal surface will be formed in the melt 500, so that the growth interface remains as a convex interface, and the seed crystal 400 grows a single crystal. When it is observed that the crystal growth interface is approaching the bottom of the growth tube 300 plug, the temperature is reduced to stop the growth.

[0042] Optionally, the seed crystal segment 301 and the equal-diameter segment 303 are both cylinders, and the inner diameter ratio of the seed crystal segment 301 and the equal-diameter segment 303 is 1:5-1:20.

[0043] As an example, the inner diameter ratio of the seed segment 301 and the constant diameter segment 303 may be 1:5, 1:6, 1:7, 1:8, 1:9, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20.

[0044] By making the inner diameter ratio of the seed crystal segment 301 and the equal diameter segment 303 within the above range, a smaller-sized seed crystal 400 can be used to seed a larger-sized single crystal, which is conducive to reducing the difficulty of preparing the seed crystal 400 and reducing production costs.

[0045] Optionally, the distance between the bottom of the heat conducting section 311 and the top of the shoulder section 302 is 15 mm to 20 mm.

[0046] As an example, the distance between the bottom of the thermally conductive segment 311 and the top of the shoulder segment 302 may be 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, or 20 mm.

[0047] By making the distance between the bottom of the heat conducting section 311 and the top of the shoulder section 302 within the above range, the heat conducting section 311 can penetrate into the melt 500 formed by the partial melting of the polycrystalline block 200, and the heat conducting section 311 is closer to the seed crystal 400 and the shoulder position, thus having a better heat conducting effect.

[0048] Optionally, the thermally conductive material 312 includes a thermally conductive rod made of silicon carbide.

[0049] Silicon carbide has a large thermal conductivity and can promptly remove the heat from the center of the melt 500 formed by the partial melting of the polycrystalline block 200 during the seeding and shoulder release stages. On the same horizontal plane, the temperature at the center of the melt 500 will be lower than the surrounding area. At this time, a convex isothermal surface will be formed in the melt 500, thereby ensuring that the solid-liquid interface 600 of the polycrystalline block 200 always remains a convex interface.

[0050] Optionally, the growth tube 300 is heated in a crystal growth furnace.

[0051] Optionally, the heat-conducting plug 310 further includes a boss section 313 , the cross section of the boss section 313 is larger than the cross section of the heat-conducting section 311 , and the boss section 313 is located at the tube opening of the growth tube 300 .

[0052] Optionally, the interior of the boss section 313 is also filled with a heat-conducting material 312 , which is beneficial to increase the heat dissipation area.

[0053] Optionally, when the distance between the crystal growth interface and the bottom of the heat conducting section 311 is 1 mm to 10 mm, the temperature is lowered to stop the growth.

[0054] As an example, the distance between the crystal growth interface and the bottom of the heat conductive section 311 when the temperature is reduced to stop the growth can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm or 10mm.

[0055] Optionally, when the distance between the crystal growth interface and the bottom of the heat conducting section 311 is 1 mm to 5 mm, the growth is stopped by cooling.

[0056] S3. Preparation of large-size single crystals See also Figure 6 and 7 First, remove the heat plug 310, replace the sealing plug 320 to re-seal and connect, take the position where the crystal growth is stopped as the starting point of the crystal growth, heat the growth tube 300 again to increase the temperature and grow the crystal. Since a single crystal has been obtained before, it will continue to grow as a single crystal in the future.

[0057] Optionally, the heat-conducting plug 310 further includes a groove 314 located on the outer wall, and the position of the groove 314 corresponds to the heat-conducting plug 310 .

[0058] When using the sealing plug 320 to replace the thermal plug 310, you can directly use a tool to gently lift up the groove 314 to separate the upper and lower parts of the growth tube 300 located in the outer wall groove 314, quickly remove the thermal plug 310 and install the sealing plug 320. This disassembly method does not require the use of a cutting machine to break the tube, and the inside of the tube can still be kept clean, so the same growth tube 300 can be used for continued growth.

[0059] It should be noted that after the heat-conducting plug 310 is removed, the single-element raw material 120 can be added to the growth tube 300 again as needed, thereby effectively increasing the length of the growing crystal and improving the crystal growth efficiency.

[0060] The crystal growth method of the present application first cooperates with the heat-conducting plug 310 having the heat-conducting section 311 through the polycrystalline block 200 having the first blind hole 211. Since the heat-conducting material 312 is filled inside the heat-conducting section 311, the heat-conducting section 311 has a large thermal conductivity, and the heat inside the melt 500 formed by partial melting of the polycrystalline block 200 can be timely exported in the seeding and shouldering stages, thereby ensuring that the solid-liquid interface 600 of the polycrystalline block 200 is always maintained as a convex interface, which is conducive to smooth seeding and can directly obtain a single crystal through the seeding and shouldering stages, and finally completes the entire crystal growth process after replacing the heat-conducting plug 310 with a sealing plug 320 to obtain a large-sized single crystal. In addition, in the initial stage of crystal growth, the heat-conducting section 311 can improve the heat-saturating effect inside the melt 500, so that the temperature field inside the crystal is highly symmetrical, which is conducive to improving the uniformity of the crystal. And the crystal growth method of the present application is simple to operate, low in cost, and highly portable, and is theoretically applicable to all types of crystal growth, especially crystal growth with low thermal conductivity.

[0061] See also Figures 5 to 8 The present application also provides a crystal growth device 10, which includes a growth tube 300, a heat-conducting plug 310, a sealing plug 320, a seed crystal 400 and a polycrystalline block 200, wherein the heat-conducting plug 310 and the sealing plug 320 are used to seal the tube openings of the growth tube 300 respectively, wherein the heat-conducting plug 310 includes a heat-conducting section 311 filled with a heat-conducting material 312, the seed crystal 400 is arranged at the bottom of the growth tube 300, the polycrystalline block 200 is arranged in the growth tube 300, and the polycrystalline block 200 has a first blind hole 211 located in the middle and facing upward, and the first blind hole 211 and the heat-conducting section 311 cooperate.

[0062] The crystal growth device 10 of the present application can be used to grow large-sized single crystals. During the crystal growth process, the polycrystalline block 200 with the first blind hole 211 cooperates with the heat-conducting plug 310 with the heat-conducting section 311. Since the heat-conducting material 312 is filled inside the heat-conducting section 311, the heat-conducting section 311 has a large thermal conductivity, and can timely remove the heat inside the melt 500 formed by partial melting of the polycrystalline block 200 during the seeding and shouldering stages, thereby ensuring that the solid-liquid interface 600 of the polycrystalline block 200 always remains as a convex interface, which is conducive to smooth seeding and directly obtaining a single crystal through the seeding and shouldering stages. Finally, after replacing the heat-conducting plug 310 with a sealing plug 320, the entire crystal growth process is completed to obtain a large-sized single crystal. In addition, in the initial stage of crystal growth, the heat-conducting section 311 can improve the heat-equalizing effect inside the melt 500, so that the temperature field inside the crystal is highly symmetrical, which is conducive to improving the uniformity of the crystal.

[0063] The crystal growth method and the crystal growth device of the present application are further described in detail below in conjunction with the embodiments.

[0064] Example 1 The present application provides a 2-inch cadmium zinc telluride (Cd 0.9 Zn 0.1 Te) crystal growth method, which comprises the following steps: S1. Preparation of polycrystalline block 200 See also Figure 1 and 2 , take out the combining tube 100 so that the tube mouth of the combining tube 100 faces upward, and the cross-section of the combining tube 100 is circular, first put the single element Te, single element Zn and single element Cd in the combining tube 100, and use the boss plug 110 to seal the tube mouth of the combining tube 100, the boss plug 110 includes an annular boss 111 and a second blind hole 112 located in the middle, when the tube mouth of the combining tube 100 faces upward, the second blind hole 112 also faces upward; then put the combining tube 100 into the synthesis furnace, heat it to 1130℃, the single element Te, single element Zn and single element Cd are completely melted to obtain liquid raw materials, and then rotate the combining tube 100 so that the boss plug 110 faces downward, at this time the second blind hole 112 also faces downward, the liquid raw material fills the annular boss 111, and finally cools down to solidify the liquid raw material to form a polycrystalline block 200.

[0065] See also Figure 3~4 The obtained polycrystalline block 200 is cylindrical as a whole, and the polycrystalline block 200 includes a blind hole section 210 and a support section 220 extending sequentially along the length direction, the volume ratio of the blind hole section 210 and the support section 220 is 5:1, the blind hole section 210 includes a first blind hole 211 distributed along the axial direction and located in the middle of the cross section of the blind hole section 210, and the ratio of the outer diameter of the polycrystalline block 200 to the inner diameter of the first blind hole 211 is 2:1.

[0066] S2, seeding See also Figure 5 and 6 , take out the growth tube 300 so that the tube mouth of the growth tube 300 faces upward, the growth tube 300 includes a seed crystal segment 301, a shoulder segment 302 and an equal diameter segment 303 extending in sequence along the length direction, the seed crystal segment 301 and the equal diameter segment 303 are both cylinders, and the inner diameter ratio of the seed crystal segment 301 and the equal diameter segment 303 is 1:5. First, a cadmium zinc telluride seed crystal 400 is placed in the seed crystal section 301, and then the obtained polycrystalline material block 200 is placed in the growth tube 300 in a manner that the first blind hole 211 faces upward, and a heat conductive plug 310 is used to seal the tube mouth of the growth tube 300. The heat conductive plug 310 includes a heat conductive section 311 and a boss section 313. The cross section of the boss section 313 is larger than the cross section of the heat conductive section 311. The heat conductive section 311 is inserted into the first blind hole 211 and matched with the first blind hole 211. The boss section 313 is located at the tube mouth of the growth tube 300. A heat conductive rod made of silicon carbide is filled in the heat conductive section 311 and the boss section 313. The bottom of the heat conductive section 311 is aligned with the shoulder section 301. 2 is 18mm; the growth tube 300 is then placed in a crystal growth furnace and heated to 1130°C. The polycrystalline block 200 is partially melted to form a melt 500. The melt 500 contacts the heat conducting section 311. Since the heat conducting section 311 is filled with a heat conducting rod, the heat at the center of the melt 500 is conducted away at a very fast speed. On the same horizontal plane, the temperature at the center of the melt 500 is lower than that at the surroundings. At this time, a convex isothermal surface is formed in the melt 500, thereby keeping the growth interface as a convex interface. The seed crystal 400 grows a single crystal. When it is observed that the distance between the crystal growth interface and the bottom of the heat conducting section 311 is 10mm, the growth is stopped by cooling.

[0067] S3. Preparation of large-size single crystals See also Figure 7 and 8 First, use a screwdriver to gently open the groove 314 of the growth tube 300, separate the upper and lower parts of the growth tube 300 located at the outer wall groove 314, thereby removing the heat plug 310, replacing the upper sealing plug 320 for re-sealing and connection, and using the position where the crystal growth is stopped as the starting point of the crystal growth to heat the growth tube 300 to 1130°C again for crystal growth. Since a single crystal has been obtained by seeding before, it will continue to grow as a single crystal until the polycrystalline block 200 completes the crystal growth process.

[0068] Example 2 The present application provides a 4-inch cadmium zinc telluride (Cd 0.9 Zn 0.1 Te) crystal growth method, which comprises the following steps: S1. Preparation of polycrystalline block 200 See also Figure 1 and 2, take out the combining tube 100 so that the tube mouth of the combining tube 100 faces upward, and the cross-section of the combining tube 100 is circular, first put the single element Te, single element Zn and single element Cd in the combining tube 100, and use the boss plug 110 to seal the tube mouth of the combining tube 100, the boss plug 110 includes an annular boss 111 and a second blind hole 112 located in the middle, when the tube mouth of the combining tube 100 faces upward, the second blind hole 112 also faces upward; then put the combining tube 100 into the synthesis furnace, heat it to 1135℃, the single element Te, single element Zn and single element Cd are completely melted to obtain liquid raw materials, and then rotate the combining tube 100 so that the boss plug 110 faces downward, at this time the second blind hole 112 also faces downward, the liquid raw material fills the annular boss 111, and finally cools down to solidify the liquid raw material to form a polycrystalline block 200.

[0069] See also Figure 3~4 The obtained polycrystalline block 200 is cylindrical as a whole, and the polycrystalline block 200 includes a blind hole section 210 and a support section 220 extending sequentially along the length direction, the volume ratio of the blind hole section 210 and the support section 220 is 6:1, the blind hole section 210 includes a first blind hole 211 distributed along the axial direction and located in the middle of the cross section of the blind hole section 210, and the ratio of the outer diameter of the polycrystalline block 200 to the inner diameter of the first blind hole 211 is 3:1.

[0070] S2, seeding See also Figure 5 and 6, take out the growth tube 300 so that the tube mouth of the growth tube 300 faces upward, the growth tube 300 includes a seed crystal segment 301, a shoulder segment 302 and an equal diameter segment 303 extending in sequence along the length direction, the seed crystal segment 301 and the equal diameter segment 303 are both cylinders, and the inner diameter ratio of the seed crystal segment 301 and the equal diameter segment 303 is 1:5. First, a cadmium zinc telluride seed crystal 400 is placed in the seed crystal section 301, and then the obtained polycrystalline material block 200 is placed in the growth tube 300 in a manner that the first blind hole 211 faces upward, and a heat conductive plug 310 is used to seal the tube mouth of the growth tube 300. The heat conductive plug 310 includes a heat conductive section 311 and a boss section 313. The cross section of the boss section 313 is larger than the cross section of the heat conductive section 311. The heat conductive section 311 is inserted into the first blind hole 211 and matched with the first blind hole 211. The boss section 313 is located at the tube mouth of the growth tube 300. A heat conductive rod made of silicon carbide is filled in the heat conductive section 311 and the boss section 313. The bottom of the heat conductive section 311 is aligned with the shoulder section 301. 2 is 18mm; the growth tube 300 is then placed in a crystal growth furnace and heated to 1135°C. The polycrystalline block 200 is partially melted to form a melt 500. The melt 500 contacts the heat conducting section 311. Since the heat conducting section 311 is filled with a heat conducting rod, the heat at the center of the melt 500 is conducted away at a very fast speed. On the same horizontal plane, the temperature at the center of the melt 500 is lower than that at the surroundings. At this time, a convex isothermal surface is formed in the melt 500, thereby keeping the growth interface as a convex interface. The seed crystal 400 grows a single crystal. When it is observed that the distance between the crystal growth interface and the bottom of the heat conducting section 311 is 10mm, the growth is stopped by cooling.

[0071] S3. Preparation of large-size single crystals See also Figure 7 and 8 First, use a screwdriver to gently open the groove 314 of the growth tube 300, separate the upper and lower parts of the growth tube 300 located at the outer wall groove 314, thereby removing the heat plug 310, replacing the upper sealing plug 320 for re-sealing and connection, and using the position where the crystal growth is stopped as the starting point of the crystal growth to heat the growth tube 300 to 1135°C again for crystal growth. Since a single crystal has been obtained by seeding before, it will continue to grow as a single crystal until the polycrystalline block 200 completes the crystal growth process.

[0072] Example 3 The present application provides a 2-inch cadmium zinc telluride (Cd 0.9 Zn 0.1 Te) A crystal growth method, based on Example 1, wherein the inner diameter ratio of the seed crystal segment 301 and the equal diameter segment 303 is changed to 1:10, while other aspects remain unchanged.

[0073] Example 4 The present application provides a 2-inch cadmium zinc telluride (Cd 0.9 Zn 0.1Te) A crystal growth method is used, in which the distance between the bottom of the heat conducting section 311 and the top of the shoulder section 302 is changed to 15 mm based on Example 1, and the other parts remain unchanged.

[0074] Example 5 The present application provides a 2-inch cadmium zinc telluride (Cd 0.9 Zn 0.1 Te) A crystal growth method is used, in which the distance between the bottom of the heat conducting section 311 and the top of the shoulder section 302 is changed to 20 mm based on Example 1, and the other parts remain unchanged.

[0075] Example 6 The present application embodiment provides a 2-inch zinc telluride (ZnTe) crystal growth method, which includes the following steps: S1. Preparation of polycrystalline block 200 See also Figure 1 and 2 , take out the combining tube 100 so that the tube mouth of the combining tube 100 faces upward, and the cross-section of the combining tube 100 is circular, first place the single element Te and the single element Zn in the combining tube 100, and use the boss plug 110 to seal the tube mouth of the combining tube 100, the boss plug 110 includes an annular boss 111 and a second blind hole 112 located in the middle, when the tube mouth of the combining tube 100 faces upward, the second blind hole 112 also faces upward; then put the combining tube 100 into a synthesis furnace, heat it to 1260°C, the single element Te and the single element Zn are completely melted to obtain liquid raw materials, and then rotate the combining tube 100 so that the boss plug 110 faces downward, at this time the second blind hole 112 also faces downward, the liquid raw material fills the annular boss 111, and finally cools down to solidify the liquid raw material to form a polycrystalline block 200.

[0076] See also Figure 3~4 The obtained polycrystalline block 200 is cylindrical as a whole, and the polycrystalline block 200 includes a blind hole section 210 and a support section 220 extending sequentially along the length direction, the volume ratio of the blind hole section 210 and the support section 220 is 5:1, the blind hole section 210 includes a first blind hole 211 distributed along the axial direction and located in the middle of the cross section of the blind hole section 210, and the ratio of the outer diameter of the polycrystalline block 200 to the inner diameter of the first blind hole 211 is 2:1.

[0077] S2, seeding See also Figure 5 and 6, take out the growth tube 300 so that the tube mouth of the growth tube 300 faces upward, the growth tube 300 includes a seed crystal segment 301, a shoulder segment 302 and an equal diameter segment 303 extending in sequence along the length direction, the seed crystal segment 301 and the equal diameter segment 303 are both cylinders, and the inner diameter ratio of the seed crystal segment 301 and the equal diameter segment 303 is 1:5. First, a zinc telluride seed crystal 400 is placed in the seed crystal section 301, and then the obtained polycrystalline material block 200 is placed in the growth tube 300 in a manner that the first blind hole 211 faces upward, and a heat conductive plug 310 is used to seal the tube mouth of the growth tube 300. The heat conductive plug 310 includes a heat conductive section 311 and a boss section 313. The cross section of the boss section 313 is larger than the cross section of the heat conductive section 311. The heat conductive section 311 is inserted into the first blind hole 211 and matched with the first blind hole 211. The boss section 313 is located at the tube mouth of the growth tube 300. A heat conductive rod made of silicon carbide is filled in the heat conductive section 311 and the boss section 313. The bottom of the heat conductive section 311 is aligned with the shoulder section 301. 2 is 18mm; the growth tube 300 is then placed in a crystal growth furnace and heated to 1260°C. The polycrystalline block 200 is partially melted to form a melt 500. The melt 500 contacts the heat conducting section 311. Since the heat conducting section 311 is filled with a heat conducting rod, it will conduct the heat from the center of the melt 500 at a very fast speed. On the same horizontal plane, the temperature at the center of the melt 500 will be lower than that of the surrounding. At this time, a convex isothermal surface will be formed in the melt 500, so that the growth interface remains as a convex interface. The seed crystal 400 grows a single crystal. When it is observed that the distance between the crystal growth interface and the bottom of the heat conducting section 311 is 10mm, the temperature is reduced to stop the growth.

[0078] S3. Preparation of large-size single crystals See also Figure 7 and 8 First, use a screwdriver to gently open the groove 314 of the growth tube 300, separate the upper and lower parts of the growth tube 300 located at the outer wall groove 314, thereby removing the heat plug 310, replacing the upper sealing plug 320 for re-sealing and connection, and using the position where the crystal growth is stopped as the starting point of the crystal growth to heat the growth tube 300 to 1260°C again for crystal growth. Since a single crystal has been obtained by seeding before, it will continue to grow as a single crystal until the polycrystalline block 200 completes the crystal growth process.

[0079] Comparative Example 1 The comparative example of the present application provides a 2-inch cadmium zinc telluride (Cd 0.9 Zn 0.1 Te) crystal growth method, which comprises the following steps: S1. Preparation of polycrystalline blocks See also Fig. 9, take out the combined tube so that the tube mouth of the combined tube faces upward, and the cross-section of the combined tube is circular, first put the single element Te, single element Zn and single element Cd in the combined tube, and use the boss plug to seal the tube mouth of the combined tube; then put the combined tube into the synthesis furnace, heat it to 1130℃, and the single element Te, single element Zn and single element Cd are completely melted to obtain liquid raw materials; finally, cool down to solidify the liquid raw materials to form polycrystalline blocks, and the polycrystalline blocks are cylindrical.

[0080] S2, seeding See also Fig.10 , take out the growth tube so that the tube mouth of the growth tube faces upward. The growth tube includes a seed crystal section, a shoulder section and a constant diameter section extending in sequence along the length direction. The seed crystal section and the constant diameter section are both cylindrical, and the inner diameter ratio of the seed crystal section and the constant diameter section is 1:5. First, place the cadmium zinc telluride seed crystal in the seed crystal section, and then place the prepared polycrystalline block in the growth tube, and seal the tube mouth of the growth tube with a sealing plug; then put the growth tube into the crystal growth furnace, heat it to 1130℃, melt the polycrystalline block, and then control the support platform to slowly descend through the program to achieve crystal growth, until the polycrystalline block completes the crystal growth process.

[0081] The size of the cadmium zinc telluride seed crystal is the same as that in Example 1, and the amounts of elemental Te, elemental Zn and elemental Cd are also the same as those in Example 1.

[0082] Comparative Example 2 The comparative example of the present application provides a 4-inch cadmium zinc telluride (Cd 0.9 Zn 0.1 Te) crystal growth method, which comprises the following steps: S1. Preparation of polycrystalline blocks See also Fig. 9 , take out the combined tube so that the tube mouth of the combined tube faces upward, and the cross-section of the combined tube is circular, first put the single element Te, single element Zn and single element Cd in the combined tube, and use the boss plug to seal the tube mouth of the combined tube; then put the combined tube into the synthesis furnace, heat it to 1135℃, and the single element Te, single element Zn and single element Cd are completely melted to obtain liquid raw materials; finally, cool down to solidify the liquid raw materials to form polycrystalline blocks, and the polycrystalline blocks are cylindrical.

[0083] S2, seeding See also Fig.10 , take out the growth tube so that the tube mouth of the growth tube faces upward. The growth tube includes a seed crystal section, a shoulder section and an equal diameter section extending in sequence along the length direction. The seed crystal section and the equal diameter section are both cylindrical, and the inner diameter ratio of the seed crystal section and the equal diameter section is 1:5. First, place the cadmium zinc telluride seed crystal in the seed crystal section, and then place the prepared polycrystalline block in the growth tube, and seal the tube mouth of the growth tube with a sealing plug; then put the growth tube into the crystal growth furnace, heat it to 1135℃, melt the polycrystalline block, and then control the support platform to slowly descend through the program to achieve crystal growth, until the polycrystalline block completes the crystal growth process.

[0084] The size of the cadmium zinc telluride seed crystal is the same as that in Example 2, and the amounts of elemental Te, elemental Zn and elemental Cd are also the same as those in Example 2.

[0085] Comparative Example 3 The comparative example of the present application provides a 2-inch zinc telluride (ZnTe) crystal growth method, which comprises the following steps: S1. Preparation of polycrystalline blocks See also Fig. 9 , take out the combined tube so that the tube mouth of the combined tube faces upward, and the cross-section of the combined tube is circular. First, place the single element Te and single element Zn in the combined tube, and use a boss plug to seal the tube mouth of the combined tube; then put the combined tube into a synthesis furnace, heat it to 1260℃, and the single element Te and single element Zn are completely melted to obtain liquid raw materials; finally, cool down to solidify the liquid raw materials to form a polycrystalline block, and the polycrystalline block is cylindrical.

[0086] S2, seeding See also Fig.10 , take out the growth tube so that the tube mouth of the growth tube faces upward. The growth tube includes a seed crystal section, a shoulder section and an equal diameter section extending in sequence along the length direction. The seed crystal section and the equal diameter section are both cylindrical, and the inner diameter ratio of the seed crystal section and the equal diameter section is 1:5. First, place the zinc telluride seed crystal in the seed crystal section, and then place the prepared polycrystalline block in the growth tube, and seal the tube mouth of the growth tube with a sealing plug; then put the growth tube into the crystal growth furnace, heat it to 1260℃, melt the polycrystalline block, and then control the support platform to slowly descend through the program to achieve crystal growth, until the polycrystalline block completes the crystal growth process.

[0087] The size of the zinc telluride seed crystal is the same as that in Example 6, and the amount of elemental Te and elemental Zn used is also the same as that in Example 6.

[0088] Test Example 1 Take out the crystals obtained in Examples 1-2 and Comparative Examples 1-2, and cut the crystals along the crystal axis to visually see the distribution of the grains. When cutting, it is necessary to bond graphite to the side of the equal diameter section of the crystal to fix the crystal before cutting. The seed crystal is relatively thin and will all break along the root. The seed crystal can also be removed in advance. The cross-section grain situation after cutting is as follows Figures 11 to 14 shown.

[0089] The grain distribution photos of the cross-sections of the crystals obtained in Example 1 and Comparative Example 1 along the axis are as follows: Figures 11-12 As shown by Fig.11 It can be seen that the color of the entire cross section is uniform, indicating that the grains prepared in Example 1 are all large grains in the entire cross section; Fig.12It can be seen that there are many dividing lines and multiple grains in the entire cross-section, which means that when the grains obtained in Comparative Example 1 are introduced from the seed crystal, polycrystalline is generated in the shoulder release stage, and they no longer grow as a single grain along the seed crystal. Although the grains will grow later, they are still relatively messy.

[0090] The grain distribution photos of the cross-sections of the crystals obtained in Example 2 and Comparative Example 2 along the axis are as follows: Figures 13 and 14 As shown by Fig.13 It can be seen that the color of the entire cross section is uniform, indicating that the grains prepared in Example 2 are all large grains in the entire cross section; Fig.14 It can be seen that there are many dividing lines and multiple grains in the entire cross-section, which means that when the grains obtained in Comparative Example 2 are introduced from the seed crystal, polycrystalline is generated in the shoulder release stage, and they no longer grow as a single grain along the seed crystal. Although the grains will grow later, they are still relatively messy.

[0091] Test Example 2 The crystals obtained in Examples 1 to 6 and Comparative Examples 1 to 3 were taken out. These crystals are usually used to process various types of photoelectric detection devices. When cutting the ingots, it is necessary to first orient the crystals according to the crystal orientation requirements, and then select the single crystal area for single crystal cutting. The results are shown in Table 1.

[0092] Table 1 Number of cuts of crystals of Examples 1 to 6 and Comparative Examples 1 to 3

[0093] By comparing Examples 1, 3 to 5 with Comparative Example 1, it can be seen that the 2-inch cadmium zinc telluride (Cd 0.9 Zn 0.1 The grain size of the Te) crystal is significantly improved, and the number of single crystal specification slices cut out increases.

[0094] From the comparison between Example 2 and Comparative Example 2, it can be seen that the 4-inch cadmium zinc telluride (Cd 0.9 Zn 0.1 The grain size of the Te) crystal is significantly improved, and the number of single crystal specification slices cut out increases.

[0095] From the comparison between Example 6 and Comparative Example 3, it can be seen that the grain size of the 2-inch zinc telluride (ZnTe) crystal obtained by the crystal growth method of the present application is significantly improved, and the number of single crystal specification sheets cut out is increased.

[0096] The above description is only a specific embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. 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 method, characterized in that: The crystal growth method comprises: firstly placing a seed crystal at the bottom of a growth tube and placing a polycrystalline block in the growth tube, wherein the polycrystalline block has a first blind hole located in the middle and facing upward, and sealing the tube mouth of the growth tube with a heat conductive plug, wherein the heat conductive plug comprises a heat conductive section filled with a heat conductive material, and the heat conductive section is inserted into the first blind hole and matched with the first blind hole, and then the growth tube is heated until the polycrystalline block is melted, and when the seed crystal starts to grow until the distance between the crystal growth interface and the bottom of the heat conductive section is 1 mm to 10 mm, the growth is stopped by cooling, and then the heat conductive plug is replaced by a sealing plug, and the position where the crystal growth is stopped is used as the starting point of the crystal growth, and the growth tube is heated again to increase the temperature and grow the crystal until the polycrystalline block completes the crystal growth process.

2. The crystal growth method according to claim 1, characterized in that The polycrystalline block comprises a blind hole section and a support section extending sequentially along the length direction, the first blind hole is located in the blind hole section, and the volume ratio of the blind hole section to the support section is 4:1-8:

1.

3. The crystal growth method according to claim 2, characterized in that: The polycrystalline block is a cylinder, and the ratio of the outer diameter of the polycrystalline block to the inner diameter of the first blind hole is 2:1-3:

1.

4. The crystal growth method according to any one of claims 1 to 3, characterized in that The polycrystalline block is prepared by the following method: First, the single-element raw material is placed in a combining tube, and the tube mouth of the combining tube is sealed with a boss plug, wherein the boss plug includes an annular boss and a second blind hole located in the middle; then, the combining tube is heated until the single-element raw material is completely melted to obtain liquid raw material; then, the combining tube is rotated so that the boss plug faces downward, and the liquid raw material fills the annular boss; finally, the temperature is lowered to allow the liquid raw material to solidify to form the polycrystalline block.

5. The crystal growth method according to any one of claims 1 to 3, characterized in that: The growth tube comprises a seed crystal section, a shoulder section and a constant diameter section extending in sequence along the length direction, the seed crystal is arranged in the seed crystal section, and the distance between the bottom of the heat conduction section and the top of the shoulder section is 15mm-20mm.

6. The crystal growth method according to claim 5, characterized in that: The seed crystal segment and the equal-diameter segment are both cylindrical, and the inner diameter ratio of the seed crystal segment and the equal-diameter segment is 1:5-1:

20.

7. The crystal growth method according to any one of claims 1 to 3, characterized in that: When the sealing plug is used to replace the heat-conducting plug, the heat-conducting plug is first removed, and then a single substance raw material is added to the growth tube, and then the sealing plug is used to seal the tube opening of the growth tube.

8. The crystal growth method according to any one of claims 1 to 3, characterized in that: The heat-conducting plug further includes a groove located on the outer wall, and the position of the groove corresponds to the heat-conducting plug.

9. The crystal growth method according to any one of claims 1 to 3, characterized in that: The thermally conductive material includes silicon carbide.

10. A crystal growth device used in the crystal growth method according to any one of claims 1 to 9, characterized in that: The crystal growth device includes a growth tube, a heat-conducting plug, a sealing plug, a seed crystal and a polycrystalline block, wherein the heat-conducting plug and the sealing plug are used to seal the tube openings of the growth tube respectively, wherein the heat-conducting plug includes a heat-conducting section filled with a heat-conducting material, the seed crystal is arranged at the bottom of the growth tube, the polycrystalline block is arranged in the growth tube, and the polycrystalline block has a first blind hole located in the middle and facing upwards, and the first blind hole cooperates with the heat-conducting section.

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