Crystal growth device and raw material recovery method

Abstract

Embodiments of the present specification provide a crystal growth apparatus and a raw material recovery method, the apparatus comprising: a crucible for accommodating a crystal growth raw material; at least part of the seed crystal support can be immersed in a melt formed by the crystal growth raw materials in the crucible; the seed crystal support comprises a seed crystal bonding surface; the first supporting structure is connected with one side, opposite to the seed crystal bonding surface, of the seed crystal holder, and the first supporting structure is configured to drive the seed crystal holder to rotate. The first supporting structure is arranged to drive the seed crystal holder in the crucible to rotate, so that the mass transfer rate is increased, and the crystal growth speed is increased; meanwhile, the rotation of the seed crystal support can also improve the radial solute distribution uniformity of the seed crystal bonding surface and improve the growth quality of the crystal.

Description

Technical Field

[0001] This specification relates to the field of crystal preparation technology, and in particular to a crystal growth apparatus and a raw material recovery method. Background Technology

[0002] The fabrication of semiconductor electronic devices and optoelectronic devices largely requires single-crystal materials, and their performance is often closely related to the purity, uniformity, and periodicity of the single crystal. Therefore, the preparation of semiconductor single crystals has a significant impact on semiconductor devices.

[0003] Therefore, this application provides a crystal growth apparatus and a raw material recovery method to improve the quality of crystal preparation. Summary of the Invention

[0004] This specification provides a crystal growth apparatus, comprising: a crucible for containing crystal growth raw materials; a seed crystal holder, at least a portion of which is immersable in a melt formed from the crystal growth raw materials within the crucible; the seed crystal holder including a seed bonding surface; and a first support structure connected to one side of the seed crystal holder opposite to the seed bonding surface, the first support structure being configured to drive the seed crystal holder to rotate.

[0005] In some embodiments, the seed crystal holder is disposed at the bottom of the crucible, the seed crystal bonding surface is disposed at the top of the seed crystal holder, and the bottom of the seed crystal holder is connected to the bottom of the crucible through the first support structure.

[0006] In some embodiments, the crystal growth apparatus further includes a first rotating mechanism located outside the crucible, the first rotating mechanism being magnetically connected to the first support structure, and the first rotating mechanism driving the first support structure to rotate via magnetic force.

[0007] In some embodiments, the seed crystal holder is disposed on top of the melt, the seed crystal bonding surface is located at the bottom of the seed crystal holder, and the first support structure is connected to the second rotating mechanism via a transmission connection.

[0008] In some embodiments, the crystal growth apparatus includes a second support structure, the crystal growth raw material includes a source rod, the source rod is at least partially immersed in the melt, and one end of the source rod is connected to the second support structure.

[0009] In some embodiments, the crystal growth apparatus includes a driving structure, the second support structure includes a main rod and a plurality of spaced-apart support rods, one end of each support rod is connected to at least one source rod, the other end of each support rod is connected to the main rod, the main rod is connected to the driving structure, and the driving mechanism drives the second support structure to move so that different source rods can be immersed in the melt.

[0010] In some embodiments, the main rod is connected to a telescopic structure, or each of the support rods is connected to a corresponding telescopic structure, which extends and retracts to immerse the source rod in the melt or to remove the source rod from the melt.

[0011] In some embodiments, the second support structure is connected to the third rotating mechanism, which drives the second support structure to rotate so as to rotate the source rod.

[0012] In some embodiments, the first support structure includes a plurality of support rods connected end to end in sequence, and any two adjacent support rods are connected by a bearing nesting; the rotational speed of the first support structure is 10rpm-200rpm.

[0013] In some embodiments, the crucible is connected to a third support structure, and the ratio of the rotational speed of the third support structure to the rotational speed of the first support structure is 0.4-0.75.

[0014] This specification also provides a method for recovering crystal raw materials, comprising: obtaining the remaining raw materials solidified in the crucible after crystal growth is completed; processing the remaining raw materials; and supplementing the remaining raw materials with new materials based on the processed remaining raw materials to prepare new raw materials that can be used for crystal growth.

[0015] In some embodiments, processing the remaining raw materials includes: crushing the remaining raw materials to obtain crushed particles; removing impurities from the crushed particles; and washing and drying the crushed particles after removing impurities.

[0016] In some embodiments, removing impurities from the crushed particles includes: acid washing the crushed particles.

[0017] In some embodiments, the cleaning and drying of the impurity-removed crushed particles includes: ultrasonically washing the impurity-removed crushed particles; drying the ultrasonically washed crushed particles; and grinding the dried crushed particles.

[0018] In some embodiments, the method further includes: sieving the particle size of the crushed particles to obtain first particles with a particle size greater than or equal to a preset threshold and second particles with a particle size less than the preset threshold; grinding the dried crushed particles includes: grinding at least a portion of the second particles; and supplementing the remaining raw material after processing to prepare new raw material for crystal growth includes: analyzing the ground second particles to determine the remaining material ratio; determining a compensation ratio based on the remaining material ratio and a preset ratio; supplementing the new material based on the compensation ratio; and preparing the new raw material that can be used for crystal growth based on the remaining raw material after processing and the supplemented new material.

[0019] The crystal growth apparatus and raw material recovery method provided in this specification have the following beneficial effects: (1) By setting a first support structure to drive the seed crystal holder in the crucible to rotate, the mass transfer rate is accelerated and the crystal growth speed is improved; (2) By setting the rotation of the seed crystal holder, the radial solute distribution uniformity of the seed crystal bonding surface can be improved, thereby improving the crystal growth quality; (3) By recycling the remaining raw materials after the crystal growth is completed and replenishing them with new materials, the next crystal generation can be carried out, thereby saving material costs and improving crystal growth efficiency. Attached Figure Description

[0020] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0021] Figure 1 This is a schematic diagram of the structure of a crystal growth apparatus according to some embodiments of this specification;

[0022] Figure 2 This is another schematic diagram of the crystal growth apparatus shown in some embodiments of this specification;

[0023] Figure 3 This is a schematic diagram of the connection structure of the source rod according to some embodiments of this specification;

[0024] Figure 4 This is a schematic diagram of the first support structure shown in some embodiments of this specification;

[0025] Figure 5 This is a schematic flowchart of a raw material recovery method according to some embodiments of this specification;

[0026] Figure 6 This is a schematic diagram of the process for processing residual raw materials according to some embodiments of this specification;

[0027] Figure 7This is a schematic diagram of the process for preparing new raw materials for crystal growth according to some embodiments of this specification. Detailed Implementation

[0028] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0029] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0030] Flowcharts are used in this specification to illustrate the operations performed according to the embodiments described herein. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0031] The manufacture of semiconductor and optoelectronic devices largely requires single-crystal materials, and their performance is often closely related to the purity, uniformity, and periodicity of the single crystal. Therefore, the preparation of semiconductor single crystals has a significant impact on semiconductor devices. Crystal growth, as a key process in semiconductor single crystal preparation, requires high-quality crystal growth. The liquid-phase method, as one of the main crystal growth techniques, has advantages such as fast growth speed, large crystal size, high-quality grown crystals, and wide applicability. Its basic principle is that the raw material is melted at high temperature and mixed with a flux. Due to supersaturation, the raw material precipitates at the seed crystal, thus achieving crystal growth.

[0032] The crystal growth apparatus provided in this specification accelerates the mass transfer rate and increases the crystal growth speed by setting a first support structure to drive the seed crystal holder in the crucible to rotate. At the same time, the rotation of the seed crystal holder can also improve the radial solute distribution uniformity at the seed crystal bonding surface and improve the crystal growth quality.

[0033] Figure 1 These are schematic diagrams of the crystal growth apparatus shown in some embodiments of this specification. Figure 2This is another schematic diagram of the crystal growth apparatus shown in some embodiments of this specification.

[0034] like Figure 1 and Figure 2 As shown, the crystal growth apparatus 100 may include a crucible 110, a seed crystal holder 120, and a first support structure 131. The crucible 110 serves as the reaction vessel for crystal growth, containing crystal growth raw materials (e.g., carbon, silicon, etc.). In some embodiments, during crystal growth, the crystal growth raw materials in the crucible 110 melt into a molten body, facilitating their movement to the seed crystal holder 120 for crystal growth. In some embodiments, the crucible 110 may also contain a fluxing agent, in which the crystal growth raw materials can dissolve or thaw. In some embodiments, the fluxing agent may contain the crystal growth raw materials. In some embodiments, the fluxing agent may also contain transition materials to promote crystal growth. In some embodiments, the fluxing agent may be a mixture of silicon and a small amount of transition metals or rare earth elements (Cr, Co, Al, Ce, etc.). At least a portion of the seed crystal holder 120 is immersed in the molten body within the crucible 110, allowing the molten crystal growth raw materials to move to the seed crystal holder 120 for crystal growth. In some embodiments, the seed crystal holder 120 includes a seed crystal bonding surface 121, which is immersed in the melt (i.e., the seed crystal bonding surface 121 is located below the liquid surface of the melt). The seed crystal bonding surface 121 is used to bond the seed crystal, and the crystal grows starting from the seed crystal. A first support structure 131 is connected to the other side of the seed crystal holder 120 opposite to the seed crystal bonding surface 121. The first support structure 131 is configured to drive the seed crystal holder 120 to rotate, thereby increasing the mass transfer rate and allowing the raw material in the melt to precipitate around the seed crystal more quickly, thereby improving the crystal growth rate. At the same time, the rotation of the seed crystal holder 120 in the melt can also improve the radial raw material distribution uniformity of the seed crystal bonding surface 121, making the radial growth of the crystal more uniform and improving the crystal growth quality.

[0035] In some embodiments, the crystal growth apparatus 100 may further include a heating component (not shown) that can heat the crucible 110 to provide the environmental conditions for crystal growth. Exemplarily, the heating component may include a heating furnace body, and the crucible 110 may be disposed within the heating furnace body for heating. In some embodiments, the heating component may also adjust the temperature gradient of the crucible 110 to regulate crystal growth.

[0036] Please refer to Figure 1 In some embodiments, the seed crystal holder 120 may be disposed at the bottom of the crucible 110, the seed crystal bonding surface 121 may be disposed at the top of the seed crystal holder 120, and the bottom of the seed crystal holder 120 may be connected to the bottom of the crucible 110 through the first support structure 131.

[0037] At this point, the heating assembly can be configured such that its heating temperature gradually decreases from the top of the melt to the bottom of the crucible 110. That is, the temperature at the top of the melt is higher than the temperature at the bottom (i.e., the area where the seed crystal bonding surface 121 is located), thereby generating convection in the melt. This allows the raw material from the higher-temperature area of ​​the melt to be transported to the lower-temperature area (i.e., the area where the seed crystal bonding surface 121 is located) and deposited and grown, thus promoting the crystal growth rate. For example, the heating temperature near the top of the melt can be 2000℃-2200℃, and the heating temperature near the seed crystal bonding surface 121 (the bottom of the melt) can be 1700℃-1900℃.

[0038] Correspondingly, in order for the first support structure 131 to drive the seed crystal holder 120 to rotate and simultaneously fix the seed crystal holder 120, the first support structure 131 may include a fixing member (not shown in the figure) fixed to the bottom of the crucible 110, and a rotating member (not shown in the figure) rotatably connected to the fixing member. The rotating member is connected to the bottom of the seed crystal holder 120. Fixing the seed crystal holder 120 through the fixing member prevents instability of the seed crystal holder 120 from affecting crystal growth. The rotating member drives the seed crystal holder 120 to rotate, improving the crystal growth rate and quality. For example, the fixing member may include a fixing cylinder, and the rotating member may include a rotating shaft and a bearing. The rotating shaft is connected to the inner wall of the fixing cylinder through the bearing, and the rotating shaft is connected to the seed crystal holder 120; the rotating shaft rotates relative to the fixing cylinder through the bearing, simultaneously driving the seed crystal holder 120 to rotate.

[0039] In some embodiments, the crystal growth apparatus 100 may further include a first rotating mechanism 141 that drives the first support structure 131 to rotate. The first rotating mechanism 141 is disposed outside the crucible 110 to provide a suitable working environment for the first rotating mechanism 141. The first rotating mechanism 141 is magnetically connected to the first support structure 131, so that while the first rotating mechanism 141 is located outside the crucible 110, the connection between the first rotating mechanism 141 and the first support structure 131 can prevent damage to the crucible 110 and avoid leakage of the contents of the crucible 110 (e.g., flux, melt, etc.). The first rotating mechanism 141 can drive the first support structure 131 to rotate through magnetic force, thereby causing the seed crystal holder 120 to rotate. Exemplarily, the first rotating mechanism 141 may include a non-contact rotary motor.

[0040] Please refer to Figure 2In some embodiments, the seed crystal holder 120 may also be disposed on top of the melt. In this case, the seed crystal bonding surface 121 may be located at the bottom of the seed crystal holder 120, so that the seed crystal bonding surface 121 can be immersed in the melt, and the seed crystal bonding surface 121 can be located below the liquid surface of the melt. In this case, the first support structure 131 is connected to the top of the seed crystal holder 120, and the first support structure 131 can extend from the opening of the crucible 110.

[0041] In some embodiments, to fix the seed crystal holder 120, the first support structure 131 may be physically connected to the second rotating mechanism 142. The seed crystal holder 120 is fixed by direct or indirect connection between the second rotating mechanism 142 and an external support or heating assembly (e.g., a heating furnace body). In some embodiments, the first support structure 131 and the second rotating mechanism 142 are drively connected, and the second rotating mechanism 142 drives the seed crystal holder 120 to rotate via the first support structure 131. In some embodiments, the second rotating mechanism 142 may include a drive motor, etc.

[0042] At this point, the heating assembly can be configured such that its heating temperature gradually increases from the top of the melt to the bottom of the crucible 110. That is, the temperature at the top of the melt (i.e., the region where the seed crystal bonding surface 121 is located) is lower, and the temperature at the bottom of the melt is higher, thereby generating convection in the melt. This allows the raw material from the higher-temperature region of the melt to be transported to the lower-temperature region (i.e., the region where the seed crystal bonding surface 121 is located) and deposited and grown, thus promoting the crystal growth rate. For example, the heating temperature near the bottom of the melt can be 2000℃-2200℃, and the heating temperature near the seed crystal bonding surface 121 (the top of the melt) can be 1700℃-1900℃.

[0043] Please refer to Figure 1 In some embodiments, the crystal growth material may further include a source rod, which is at least partially immersed in the melt of the crucible 110. A flux can etch the source rod, causing it to deposit and grow on the seed crystal bonding surface 121 via diffusion, dissolving in the melt and acting as a solute. In some embodiments, the source rod may be made of graphite or silicon carbide (SiC) ceramic or a single crystal to provide the raw materials required for crystal growth.

[0044] In some embodiments, the crystal growth apparatus 100 may further include a second support structure 132, one end of the source rod (e.g., the end facing away from the bottom of the crucible 110) may be connected to the second support structure 132, thereby fixing the source rod. The second support structure 132 may be directly or indirectly connected to an external support or heating assembly (e.g., a heating furnace section).

[0045] In some embodiments, the crystal growth apparatus 100 may further include a driving structure 143, and the second support structure 132 includes a main rod 132-1 and a plurality of spaced support rods 132-2. One end of each support rod 132-2 is connected to at least one source rod, and the other end of each support rod 132-2 is connected to the main rod 132-1. The main rod 132-1 is connected to the driving structure 143. The driving mechanism 143 drives the second support structure 132 to move so that different source rods can be immersed in the melt, thereby switching the source rods immersed in the melt, thereby realizing rapid switching of source rods and improving operating efficiency.

[0046] In some embodiments, the orientation of the multiple support rods 132-2 spaced apart can correspond to the driving direction of the drive structure 143, so as to enable different source rods to be immersed in the melt. For example, as Figure 1 As shown, multiple support rods 132-2 can be arranged at intervals along a circumference, and the driving direction of the driving structure 143 is in the circumferential direction. Alternatively, multiple support rods 132-2 can be arranged at intervals along a horizontal direction, and the driving direction of the driving structure 143 is in the corresponding horizontal direction.

[0047] In some embodiments, each support rod 132-2 may be connected to at least one source rod, thereby facilitating control of the number of source rods immersed in the melt and adjusting the amount of raw material in the melt, thereby controlling the crystal growth.

[0048] In some embodiments, to allow different source rods to be immersed in the melt and to avoid the crucible 110 obstructing the switching of source rods, the crucible 110 can be mounted on a lifting device (not shown in the figure). When it is necessary to switch source rods, the lifting device can be driven to descend, lowering the position of the crucible 110 and removing the source rod from the crucible 110. After the source rod is completely removed from the crucible 110, the driving structure 143 can drive the second support structure 132 to move and switch the source rod corresponding to the crucible 110. When another source rod moves above the crucible 110, the lifting device can be driven to rise, immersing the source rod in the melt to continue crystal cultivation.

[0049] In some embodiments, to allow different source rods to be immersed in the melt and to prevent the crucible 110 from hindering the switching of source rods, the raising and lowering of the source rods is also controlled. In some embodiments, the main rod 132-1 may be connected to the telescopic structure 150 (e.g., Figure 1 (As shown), or each support rod 132-2 is connected to a corresponding telescopic structure 150, and multiple telescopic structures 150 are individually or jointly connected to the drive structure 143 via the main rod. The telescopic structure 150 can extend or retract to immerse the source rod in the melt, or to remove the source rod from the melt.

[0050] The telescopic structure 150 facilitates control over crystal growth. Specifically, when the length of the source rod is known, the telescopic structure 150 immerses the source rod into the melt by a predetermined length, positioning the top of the melt at a predetermined position on the source rod. This allows control over the amount of raw material dissolved in the melt, thereby controlling the crystal growth process and parameters.

[0051] In some embodiments, the telescopic structure 150 also facilitates the replacement of the source rod. Specifically, after the source rod reaches a predetermined consumption amount (e.g., a preset length has been consumed, or it has been completely consumed), the telescopic structure 150 can be used to remove the source rod from the melt for replacement. Further, after the telescopic structure 150 removes the current source rod from the melt, the drive structure 143 can operate (e.g., drive the support rod 132-2 to rotate by a corresponding angle, or drive the support rod 132-2 to displace by a corresponding distance in the corresponding horizontal direction) to remove the current source rod from the opening of the crucible 110, while moving another source rod to the opening of the crucible 110, and immersing the other source rod in the melt through the telescopic structure 150 to replenish the raw materials in the melt.

[0052] Figure 3 This is a schematic diagram of the connection structure of the source rod according to some embodiments of this specification. Please refer to... Figure 3 In some embodiments, each support rod 132-2 may also be connected to a corresponding third rotating mechanism 144, and multiple third rotating mechanisms 144 are connected to the main rod 132-1, such as... Figure 3 As shown. Each third rotating mechanism 144 can drive the corresponding source rod to rotate, enhancing the uniformity of the contact between the source rod and the melt, accelerating the etching intensity of the source rod by the flux in the melt, strengthening the material supply, and improving the crystal formation effect.

[0053] In some embodiments, the second support structure 132 may also include only one support rod 132-2, that is, the second support structure 132 may be connected to only one source rod. In this case, the second support structure 132 may also be directly connected to the third rotating mechanism 144. The third rotating mechanism 144 can drive the second support structure 132 to rotate, thereby rotating the source rod, enhancing the uniformity of the contact between the source rod and the melt, accelerating the etching intensity of the flux in the melt on the source rod, strengthening material supply, and improving the crystal formation effect.

[0054] In some embodiments, the third rotating mechanism 144 may be connected and fixed to an external support or heating assembly (e.g., a heating furnace body). In some embodiments, the third rotating mechanism 144 may also be connected to the drive structure 143. In some embodiments, a telescopic structure 150 may be provided between the third rotating mechanism 144 and the source rod, or between the drive structure 143 and the third rotating mechanism 144, as described above.

[0055] It should be noted that, except for the first support structure 131 and the first rotation mechanism 141 when the seed crystal holder 120 is disposed at the bottom of the crucible 110, the support structures in other cases (such as the first support structure 131 and the second support structure 132 when the seed crystal holder 120 is disposed at the top of the crucible 110) can have the same or similar structures, and the rotation mechanisms (such as the second rotation mechanism 142 and the third rotation mechanism 144) can have the same or similar structures.

[0056] Figure 4 This is a structural schematic diagram of the first support structure shown according to some embodiments of this specification. For example... Figure 4 As shown, in some embodiments, the first support structure 131 may include a plurality of support rods 131-1 connected end to end in sequence, and any two adjacent support rods 131-1 can be nested together by bearings 131-2. In some embodiments, the first support structure 131 may also include a protective layer (not shown in the figure), in which the support rods 131-1 and bearings 131-2 are both disposed within the protective layer. The protective layer separates the support rods 131-1 and bearings 131-2 from the outside world, thereby providing protection and improving the working stability of the first support structure 131.

[0057] The outer ring of bearing 131-2 can be connected to the inner wall of the protective layer, and the opposite ends of two adjacent support rods 131-1 are nested in the inner ring of the corresponding bearing 131-2. By restricting the rotational sway of the support rod 131-1 through bearing 131-2, stability can be achieved when the support rod 131-1 rotates at high speed. At the same time, the arrangement of bearing 131-2 ensures that when the support rod 131-1 rotates, the inner cavity of bearing 131-2 is relatively stationary with respect to the support rod 131-1, and the outer ring of bearing 131-2 is stationary with respect to the protective layer. The wear generated by bearing 131-2 when the support rod 131-1 rotates has a small impact on the support rod 131-1, thereby improving the service life of the first support structure 131. In addition, the bearing 131-2 is easy to replace after damage, and the replacement cost is lower, thereby reducing the operating cost.

[0058] It should be noted that the structure of the first support structure 131 is the structure of the first support structure 131 when the seed crystal holder 120 is placed on top of the melt in the crucible 110. The structure of the second support structure 132 can be the same as or similar to the structure of the first support structure 131.

[0059] In some embodiments, the rotational speed of the first support structure 131 or the second support structure 132 can be 10 rpm to 200 rpm, that is, the corresponding rotational speed of the seed crystal holder 120 or the source rod can be 10 rpm to 200 rpm. By designing the rotational speed of the seed crystal holder 120, the mass transfer rate can be increased, the crystal growth rate can be improved, and the radial material distribution uniformity of the seed crystal bonding surface 121 can be improved, thereby improving the crystal growth quality. By designing the rotational speed of the source rod, the uniformity of the contact between the source rod and the melt can be enhanced, the etching rate of the source rod can be increased, and the crystal formation effect can be improved. In some embodiments, in order to further improve the crystal growth rate and the crystal growth effect, the rotational speed of the first support structure 131 or the second support structure 132 can be 20 rpm to 150 rpm.

[0060] In some embodiments, the rotational speed of the first support structure 131 is negatively correlated with the temperature at the seed crystal holder 120. When the temperature of other regions of the melt is constant, the higher the temperature at the seed crystal holder 120 (seed bonding surface 121), the smaller the temperature gradient between the seed crystal holder 120 and other regions of the melt in the axial direction, making it more difficult for the raw material in the melt to be transported to the seed crystal bonding surface 121 for deposition and growth. In this case, to improve the crystal growth rate and quality, a higher rotational speed is required for the first support structure 131. Here, the axial direction refers to the direction perpendicular to the seed crystal bonding surface 121, i.e., the depth direction of the crucible 110. Similarly, when the temperature of other regions of the melt is constant, the lower the temperature at the seed crystal holder 120 (seed bonding surface 121), the larger the temperature gradient between the seed crystal holder 120 and other regions of the melt in the axial direction, making it easier for the raw material in the melt to be transported to the seed crystal bonding surface 121 for deposition and growth. In this case, a lower rotational speed is required for the first support structure 131.

[0061] In some embodiments, the sides and top of the seed crystal holder 120 may be covered with a protective layer to protect the seed crystal holder 120, isolate the seed crystal holder 120 from the melt, and minimize the occurrence of polycrystalline growth on the seed crystal holder 120. In some embodiments, the protective layer may be fixed to the surface of the seed crystal holder by means of threaded connection or adhesive bonding.

[0062] In some embodiments, the protective layer material has high-temperature resistance to adapt to the crystal growth environment. In some embodiments, to avoid interfering with crystal growth, the protective layer material has high physicochemical stability and exhibits non-wetting properties with the melt (e.g., flux). In some embodiments, the protective layer material may include at least one of SiC, Si3N4, SiO2, Al2O3, or MgO.

[0063] In some embodiments, the thickness of the protective layer can be 0.5 mm to 20 mm to isolate the seed crystal holder 120 from the melt. In some embodiments, the thickness of the protective layer can be 1 mm to 15 mm to meet design requirements.

[0064] If the diameter of the seed crystal holder 120 differs too much from the inner diameter of the crucible 110, the melt flow rate will be low when the seed crystal holder 120 rotates, leading to uneven material distribution within the melt and insufficient contact between the melt and the seed crystal bonding surface 121, thus affecting crystal growth. If the diameter of the seed crystal holder 120 is too close to the inner diameter of the crucible 110, interference may occur when the seed crystal holder 120 rotates, posing a safety hazard. In some embodiments, to improve crystal growth and safety, the ratio of the diameter of the seed crystal holder 120 to the inner diameter of the crucible 110 can be 4 / 5 to 7 / 8. In some embodiments, to further improve crystal growth, the ratio of the diameter of the seed crystal holder 120 to the inner diameter of the crucible 110 can be 5 / 6 to 6 / 7.

[0065] In some embodiments, when the diameter of the seed crystal holder 120 is smaller than the crystal diameter, the area of ​​the seed crystal bonding surface 121 is smaller, the stress on the crystal is limited, and the crystal is less prone to cracking. When the diameter of the seed crystal holder 120 is greater than or equal to the crystal diameter, it provides better support for the crystal, resulting in a thicker and smoother crystal growth. In some embodiments, to improve the growth quality of the crystal, the ratio of the diameter of the seed crystal holder 120 to the diameter of the crystal can be 0.5-1.5.

[0066] In some embodiments, the diameter of the support rod 131-1 of the first support structure 131 affects the rotational speed of the seed crystal holder 120 and the amount of cooling medium delivered. If the diameter of the first support structure 131 is too small, the rotational speed of the seed crystal holder 120 will be limited, and the amount of cooling medium delivered will be too small, resulting in a high temperature at the seed crystal bonding surface 121, which will affect crystal growth. If the diameter of the first support structure 131 is too large, it will increase the installation difficulty and material cost. In some embodiments, in order to reduce material costs and improve crystal growth quality, the ratio of the diameter of the seed crystal holder 120 to the diameter of the support rod 131-1 can be 3.5-16. In some embodiments, in order to further improve crystal growth quality, the ratio of the diameter of the seed crystal holder 120 to the diameter of the support rod 131-1 can be 8-10.

[0067] In some embodiments, the crucible 110 may also be connected to a third support structure (not shown in the figure). The third support structure may be connected to a rotating mechanism, which drives the crucible 110 to rotate via the third support structure, thereby rotating the melt inside the crucible 110, increasing the mass transfer rate, increasing the crystal growth rate, improving the uniformity of raw material distribution within the melt, and improving the crystal growth quality. In some embodiments, to improve the crystal growth quality, the rotation speed of the third support structure may be 10 rpm to 200 rpm. In some embodiments, to further improve the crystal growth quality, the rotation speed of the third support structure may be 150 rpm to 200 rpm.

[0068] In some embodiments, the rotational speeds of the first support structure 131 and the third support structure can affect the mass transfer rate between the melt and the seed crystal bonding surface 121 within the crucible 110. When the first and third support structures rotate in the same direction, the closer their rotational speeds are to each other, the lower the mass transfer rate. In some embodiments, to improve crystal growth quality, the ratio of the rotational speed of the third support structure to that of the first support structure 131 can be 0.4-0.75.

[0069] Figure 5 This is a schematic flowchart illustrating a raw material recycling method according to some embodiments of this specification. This specification also provides a raw material recycling method that recovers and replenishes residual raw materials after crystal growth for the next crystal generation, thereby saving material costs and improving crystal growth efficiency. In some embodiments, the raw material recycling method can be performed by the crystal growth apparatus 100. In some embodiments, please refer to... Figure 5 The raw material recycling method may include process 1200, which may include the following steps:

[0070] Step 1210: After the crystal growth is completed, obtain the remaining solidified raw material in the crucible.

[0071] In some embodiments, after the previous crystal growth is completed, the crucible 110 containing residual raw material can be removed from the growth chamber to obtain the remaining raw material inside the crucible 110. The growth chamber refers to the chamber in which the crucible 110 is placed. The growth chamber provides the conditions (e.g., temperature) required for crystal growth, and the overall structure or some components such as heating and cooling components can also be disposed within the growth chamber. In some embodiments, the residual raw material may include the source rod portion etched into the melt by the flux in the melt, transition materials, etc.

[0072] In some embodiments, after the crystal growth is completed and the crucible 110 is removed, the crucible 110 is changed from a high-temperature environment to a room-temperature environment, and the remaining raw material inside the crucible 110 solidifies and adheres to the bottom of the crucible 110. In some embodiments, the solidified remaining raw material can be removed from the crucible 110 using a tool. For example, a hammer made of tungsten carbide can be used to separate the solidified material from the surface of the crucible.

[0073] Step 1220: Process the remaining raw materials.

[0074] In some embodiments, by processing the remaining raw materials, impurities can be removed to preserve the material ratios associated with the crystal growth raw materials.

[0075] Figure 6 This is a schematic diagram illustrating the process of processing residual raw materials according to some embodiments of this specification. For example... Figure 6 As shown, in some embodiments, step 1220 may include multiple sub-steps, such as steps 1221, 1222 and 1223.

[0076] Step 1221: Crush the remaining raw materials to obtain crushed particles.

[0077] By crushing the remaining raw materials, their volume can be reduced, making them easier to process later.

[0078] In some embodiments, the remaining raw materials can be crushed into solid particles of varying sizes using the aforementioned tungsten hammer. In some embodiments, process 1200 may further include: sieving the crushed particles to obtain first particles with a particle size greater than or equal to a preset threshold and second particles with a particle size less than the preset threshold. In some embodiments, the preset threshold can be pre-set or determined based on the average size of the crushed particles. In some embodiments, the preset threshold can be 3 mm, meaning that crushed particles with a particle size greater than or equal to 3 mm after sieving can be classified as first particles, while crushed particles with a particle size less than 3 mm after sieving can be classified as second particles. Specifically, the crushed particles can be sieved using a sieve with a sieve aperture size of the preset threshold; the separated crushed particles are the second particles, and the remaining unseparated crushed particles are the first particles. During subsequent crystal growth, when heating and melting the material, the larger first particles can reduce the degree of component volatilization, while the smaller second particles can fill the gaps between the first particles, improving heat transfer capacity and reducing power loss. In some embodiments, the first and second particles can be separated using a sieve.

[0079] Step 1222: Remove impurities from the crushed particles.

[0080] Because impurities may be introduced into the crushed particles during the crushing and separation process, it is necessary to remove impurities from the crushed particles to minimize interference and improve the accuracy and reliability of subsequent measurements. In some embodiments, impurities may also include transition substances (e.g., transition metal ions), other substances (e.g., oxidation products of raw materials, such as SiO2), etc.

[0081] In some embodiments, step 1222 may include: acid washing the crushed particles.

[0082] In some embodiments, impurities can be removed by acid washing. For example, the crushed particles can be acid-washed using a mixture of hydrofluoric acid (HF) and hydrochloric acid (HCl) in a 1:1 volume ratio. HF can be used to remove SiO2, and HCl can be used to remove metal impurity ions.

[0083] Step 1223: Clean and dry the crushed particles after impurity removal.

[0084] After impurity removal, substances used in the process (e.g., acids) may remain on the surface of the crushed particles. Cleaning the crushed particles after impurity removal removes these substances, reducing interference and improving accuracy.

[0085] In some embodiments, the crushed particles after cleaning can be dried to remove water adhering to the surface of the crushed particles during the cleaning process, thereby reducing interference and improving accuracy.

[0086] In some embodiments, step 1223 may include: ultrasonically washing the impurity-removed crushed particles; drying the ultrasonically washed crushed particles; and grinding the dried crushed particles.

[0087] In some embodiments, ultrasonic equipment can be used to wash the purified crushed particles in an ultrapure water medium to remove acid adhering to the surface of the crushed particles. In some embodiments, if the ultrasonic washing time is too short, the removal effect of acid adhering to the surface of the crushed particles will be poor, while if the ultrasonic washing time is too long, it will seriously restrict the production progress and may further refine the larger first particles into smaller second particles, which is not conducive to particle size control. In some embodiments, the ultrasonic washing time can be 20 min-50 min to remove as much acid as possible from the surface of the crushed particles. For example, the ultrasonic washing time can be 30 min.

[0088] In some embodiments, when drying the ultrasonically washed crushed particles, if the drying temperature is too low, the required baking time is long and the drying effect is poor. If the drying temperature is too high, the crushed particles may agglomerate, resulting in an increase in particle size and wasted power. In some embodiments, the drying temperature can be 120°C-170°C to achieve a better drying effect. For example, the drying temperature can be 150°C. In some embodiments, the drying time can be negatively correlated with the drying temperature. In some embodiments, drying can be carried out for 12 hours at a drying temperature of 150°C.

[0089] In some embodiments, the dried crushed particles have a low impurity content and can be pretreated for subsequent analysis. In some embodiments, the dried crushed particles can be ground to determine the component proportions of the crushed particles. In some embodiments, to reduce grinding difficulty, smaller second particles can be ground. To reduce material waste, and since the crushed particles have the same composition, only a portion of the second particles can be ground. That is, grinding the dried crushed particles can include grinding at least a portion of the second particles.

[0090] Step 1230: Based on the remaining raw materials after processing, add new materials to prepare new raw materials for crystal growth.

[0091] In some embodiments, based on the remaining raw materials after processing, the proportion of each group of crushed particles can be determined, and based on the preset proportion of crystal growth raw materials, new materials can be added accordingly to prepare new raw materials for crystal growth.

[0092] Figure 7 This is a schematic flowchart illustrating the preparation of new raw materials for crystal growth according to some embodiments of this specification. Please refer to... Figure 7 In some embodiments, step 1230 may include multiple sub-steps, such as steps 1231, 1232, 1233 and 1234.

[0093] Step 1231: Analyze the second batch of ground particles to determine the proportion of the remaining material.

[0094] In some embodiments, because the second particles are small in size and easy to grind, at least one sample can be taken from the second particles for grinding. In some embodiments, grinding can be performed using a mortar and pestle. In some embodiments, at least 5 samples are ground to improve accuracy.

[0095] In some embodiments, mechanical instruments (such as elemental analysis instruments) can be used to quantitatively analyze the elements and content in the sample powder obtained by grinding, and to calculate the remaining proportion and content of each component in the remaining raw material in crucible 110.

[0096] Step 1232: Determine the compensation ratio based on the remaining material ratio and the preset ratio.

[0097] The preset ratio refers to the proportion of crystal growth materials used in crystal growth culture. This preset ratio can be added by the user temporarily or obtained from past records.

[0098] Based on the preset ratio and the ratio of the remaining materials, the supplementary ratio required to adjust the ratio of each component in the remaining raw materials to the preset ratio can be determined.

[0099] Step 1233: Add new material based on the compensation ratio.

[0100] Once the compensation ratio is determined, the corresponding amount of new material can be added according to the compensation ratio.

[0101] Steps 1, 2, 3, and 4: Based on the remaining raw materials after processing and the supplemented new materials, prepare new raw materials for crystal growth.

[0102] The remaining raw materials after processing are mixed with the new materials to obtain the new crystal growth raw materials required for the next crystal growth.

[0103] In some embodiments, since there is significant volatilization during crystal growth, in order to compensate for the volatilized portion, the volatilized material can be randomly sampled and the volatilization ratio can be obtained. Based on the volatilization ratio, an excess of powder can be added to the newly prepared raw material to compensate for volatilization and improve the crystal growth accuracy.

[0104] Step 1240: Crystal growth based on new raw materials.

[0105] Based on the newly prepared raw materials, the next crystal growth is carried out.

[0106] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0107] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0108] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0109] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ general methods of digit preservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such numerical values ​​are set as precisely as feasible.

[0110] Finally, it should be understood that the embodiments described in this application are merely illustrative of the principles of the embodiments of this application. Other modifications may also fall within the scope of this application. Therefore, alternative configurations of the embodiments of this application are considered as examples and not limitations, and are regarded as consistent with the teachings of this application. Accordingly, the embodiments of this application are not limited to the embodiments explicitly described and illustrated in this application.

Claims

1. A crystal growth apparatus, characterized in that, The device includes: Crucibles are used to hold raw materials for crystal growth. The seed crystal holder, at least a portion of which is capable of being immersed in the melt formed from the crystal growth raw material within the crucible; the seed crystal holder includes a seed crystal bonding surface; A first support structure is connected to the side of the seed crystal holder opposite to the bonding surface of the seed crystal, and the first support structure is configured to drive the seed crystal holder to rotate.

2. The crystal growth apparatus as described in claim 1, characterized in that, The seed crystal holder is disposed at the bottom of the crucible, the seed crystal bonding surface is disposed at the top of the seed crystal holder, and the bottom of the seed crystal holder is connected to the bottom of the crucible through the first support structure.

3. The crystal growth apparatus as described in claim 2, characterized in that, The crystal growth apparatus further includes a first rotating mechanism located outside the crucible. The first rotating mechanism is magnetically connected to the first support structure, and the first rotating mechanism drives the first support structure to rotate through magnetic force.

4. The crystal growth apparatus as described in claim 1, characterized in that, The seed crystal holder is disposed on the top of the melt, the seed crystal bonding surface is located at the bottom of the seed crystal holder, and the first support structure is connected to the second rotating mechanism via transmission.

5. The crystal growth apparatus as described in claim 1, characterized in that, The crystal growth apparatus includes a second support structure, the crystal growth raw material includes a source rod, the source rod can be at least partially immersed in the melt, and one end of the source rod is connected to the second support structure.

6. The crystal growth apparatus as described in claim 5, characterized in that, The crystal growth apparatus includes a driving structure, and the second support structure includes a main rod and a plurality of spaced-apart support rods. One end of each support rod is connected to at least one of the source rods, and the other end of each support rod is connected to the main rod. The main rod is connected to the driving structure, and the driving mechanism drives the second support structure to move so that different source rods can be immersed in the melt.

7. The crystal growth apparatus as described in claim 6, characterized in that, The main rod is connected to a telescopic structure, or each of the support rods is connected to a corresponding telescopic structure, which extends and retracts to immerse the source rod in the melt or to remove the source rod from the melt.

8. The crystal growth apparatus as described in claim 5, characterized in that, The second support structure is connected to the third rotating mechanism, which drives the second support structure to rotate so as to drive the source rod to rotate.

9. The crystal growth apparatus as described in claim 4, characterized in that, The first support structure includes multiple support rods connected end to end in sequence, and any two adjacent support rods are connected by a bearing nesting. The rotational speed of the first support structure is 10 rpm to 200 rpm.

10. The crystal growth apparatus as claimed in claim 1, wherein the crucible is connected to the third support structure, and the ratio of the rotational speed of the third support structure to the rotational speed of the first support structure is 0.4-0.

75.

11. A method for recovering crystalline raw materials, comprising: After crystal growth is complete, the remaining solidified raw material in the crucible is collected; The remaining raw materials are processed; Based on the remaining raw materials after processing, new materials are added to prepare new raw materials that can be used for crystal growth.

12. The method as described in claim 11, characterized in that, The processing of the remaining raw materials includes: The remaining raw materials are crushed to obtain crushed particles; The crushed particles are then cleaned of impurities. The crushed particles after impurity removal are then washed and dried.

13. The method as described in claim 12, characterized in that, The impurity removal process for the crushed particles includes: acid washing of the crushed particles.

14. The method as described in claim 12, characterized in that, The process of washing and drying the crushed particles after impurity removal includes: The crushed particles after impurity removal are subjected to ultrasonic water washing; The broken particles after ultrasonic washing are dried. The dried and crushed particles are then ground.

15. The method as described in claim 14, characterized in that, The method further includes: sieving the particle size of the crushed particles to obtain a first particle with a particle size greater than or equal to a preset threshold and a second particle with a particle size less than the preset threshold. The grinding of the dried crushed particles includes: grinding at least a portion of the second particles; The process of replenishing the remaining raw materials after processing with new materials to prepare new raw materials for crystal growth includes: The second batch of particles after grinding was analyzed to determine the proportion of the remaining material. Based on the remaining material ratio and the preset ratio, a compensation ratio is determined; Based on the aforementioned compensation ratio, the new material is added; Based on the processed remaining raw materials and the supplemented new materials, the new raw materials that can be used for crystal growth are prepared.

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