A method of crystal production

Abstract

This specification provides a method for preparing a crystal. The method includes: placing a raw material in a growth chamber; lowering a pulling assembly with a seed crystal attached to it to the vicinity of the raw material, wherein the pulling assembly is drive-connected to a guiding assembly, the guiding assembly includes a cylinder, and the pulling assembly is at least partially located within the cylinder; heating the growth chamber to form a raw material melt; and growing a crystal based on the seed crystal and the raw material melt through the drive motion of the pulling assembly and the guiding assembly.

Description

[0001] Case Analysis

[0002] This application is a divisional application of Chinese application filed on July 19, 2022, with application number 202210847948.5 and entitled "A Crystal Preparation Apparatus". Technical Field

[0003] This specification relates to the field of crystal preparation technology, and in particular to an apparatus and method for preparing crystals based on a liquid phase method. Background Technology

[0004] When preparing crystals (e.g., silicon carbide) using liquid-phase methods (e.g., the top-seeded solution method, TSSG), some components in the raw materials (e.g., silicon) are easily volatilized at high temperatures, which can lead to melt component segregation and spontaneous nucleation at the seed crystal surface or melt surface. Furthermore, changes in the melt surface during the Czochralski growth process cause variations in the temperature field, affecting the normal growth of the crystal. Therefore, it is necessary to provide an improved crystal preparation apparatus and method to ensure normal crystal growth. Summary of the Invention

[0005] One embodiment of this specification provides a crystal preparation apparatus. The crystal preparation apparatus includes: a growth chamber for placing raw materials; a heating assembly for heating the growth chamber; a lifting assembly for lifting and growing the raw materials; and a guiding assembly, the guiding assembly including a cylinder, the lifting assembly being at least partially located inside the cylinder, and the lifting assembly being drively connected to the guiding assembly.

[0006] In some embodiments, the diameter of the cylinder gradually increases from the bottom to the top of the cylinder.

[0007] In some embodiments, the thickness of the cylinder is in the range of 1mm-3mm.

[0008] In some embodiments, the angle between the sidewall of the cylinder and the horizontal plane is in the range of 100°-140°.

[0009] In some embodiments, the sidewall of the cylinder is provided with a through hole.

[0010] In some embodiments, the diameter of the through hole is in the range of 0.5 mm to 2 mm.

[0011] In some embodiments, the distance between the through hole and the bottom of the cylinder is in the range of 3mm-10mm.

[0012] In some embodiments, the density of the through holes is 3 holes / cm². 2 -10 pieces / cm 2Within the range.

[0013] In some embodiments, graphite paper is disposed at the bottom of the cylinder.

[0014] In some embodiments, the guiding component further includes a transmission mechanism that is tractively connected to the cylinder to enable the cylinder to move up and down. Attached Figure Description

[0015] 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:

[0016] Figure 1 This is a schematic diagram of the structure of an exemplary crystal preparation apparatus according to some embodiments of this specification;

[0017] Figure 2 These are schematic diagrams of the structures of exemplary lifting and guiding components according to some embodiments of this specification;

[0018] Figure 3 This is a schematic diagram of an exemplary heating and material preparation stage according to some embodiments of this specification;

[0019] Figure 4 This is a schematic diagram of an exemplary lead-in stage according to some embodiments of this specification;

[0020] Figure 5 This is a schematic diagram illustrating an exemplary lifting and growth stage according to some embodiments of this specification;

[0021] Figure 6 This is a schematic diagram illustrating an exemplary lifting and growth stage according to other embodiments of this specification;

[0022] Figure 7 This is a schematic diagram illustrating the end of exemplary crystal growth according to some embodiments of this specification;

[0023] Figure 8 This is a schematic diagram of the structure of an exemplary temperature measuring device according to some embodiments of this specification;

[0024] Figure 9 This is a flowchart illustrating an exemplary crystal preparation method according to some embodiments of this specification.

[0025] In the diagram, 100 is the crystal preparation device, 110 is the growth chamber, 120 is the heating component, 130 is the lifting component, 131 is the seed crystal holder, 132 is the lifting rod, 140 is the guiding component, 141 is the cylinder, 1411 is the through hole, 1411' is the bottommost through hole, 1412 is the graphite paper, 142 is the transmission mechanism, 1421 is the connecting ring, 1422 is the connector, 1423 is the rotating shaft, 1424 is the stop block, 1425 is the support frame, 150 is the heat preservation component, 160 is the furnace body, 170 is the observation component, 180 is the sensing component, 800 is the temperature measuring device, 810 is the support component, 820 is the driving component, 821 is the fixing component, 822 is the lead screw, 823 is the power component, and 830 is the temperature measuring component. Detailed Implementation

[0026] 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.

[0027] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0028] 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.

[0029] Figure 1 This is a schematic diagram of the structure of an exemplary crystal preparation apparatus according to some embodiments of this specification.

[0030] In some embodiments, the crystal preparation apparatus 100 can prepare crystals (e.g., silicon carbide) based on a liquid-phase method. The crystal preparation apparatus 100 described in detail below, with reference to the accompanying drawings and using the preparation of silicon carbide crystals as an example, will be explained in detail. It is worth noting that the following embodiments are merely illustrative of this specification and do not constitute a limitation thereof.

[0031] like Figure 1 As shown, the crystal preparation apparatus 100 may include a growth chamber 110, a heating component 120, a lifting component 130, and a guiding component 140.

[0032] The growth chamber 110 can serve as the site for crystal preparation. The heating assembly 120 can be used to heat the growth chamber 110 to provide the heat (e.g., temperature, temperature field, etc.) required for crystal preparation.

[0033] In some embodiments, the material of the growth chamber 110 can be determined according to the type of crystal to be prepared. For example, when preparing silicon carbide crystals, the material of the growth chamber 110 may include graphite. Graphite can serve as a carbon source, providing the carbon required for preparing silicon carbide crystals. In some embodiments, the material of the growth chamber 110 may also include molybdenum, tungsten, tantalum, etc. In some embodiments, the raw materials required for crystal preparation (e.g., silicon powder, carbon powder) may be placed inside the growth chamber 110. In some embodiments, the growth chamber 110 may be a place where the raw materials melt to form a melt. For example, under the high temperature generated by the heating component 120, the silicon powder melts into a melt (liquid state), and the carbon provided by the growth chamber 110 itself dissolves in the silicon solution to form a carbon solution in silicon, which serves as a liquid raw material for preparing silicon carbide crystals by the liquid phase method. In some embodiments, to improve the solubility of carbon in silicon, fluxes (e.g., aluminum, silicon-chromium alloy, Li-Si alloy, Ti-Si alloy, Fe-Si alloy, Sc-Si alloy, Co-Si alloy, etc.) may be added to the raw materials.

[0034] In some embodiments, the heating assembly 120 may include an induction heating assembly, a resistance heating assembly, etc. In some embodiments, the heating assembly 120 may be disposed around the outer periphery of the growth chamber 110. In some embodiments, such as Figure 1 As shown, the heating assembly 120 may include an induction coil. In some embodiments, the induction coil may be disposed around the outer periphery of the growth chamber 110.

[0035] In some embodiments, the lifting component 130 can move up and down and / or rotate to perform lifting growth. In some embodiments, such as Figure 1 As shown, the lifting assembly 130 may include a seed crystal holder 131 and a lifting rod 132. In some embodiments, the seed crystal (e.g., Figure 1 The part (shown as "A") can be adhered to the lower surface of the seed crystal holder 131. In some embodiments, the lifting rod 132 can be connected to the seed crystal holder 131 to drive the seed crystal holder 131 to move up and down and / or rotate.

[0036] In some embodiments, the guide component 140 may be drive-connected to the lifting component 130. In some embodiments, the guide component 140 may be drive-moving with the lifting component 130. For a related description of the lifting component 130 and the guide component 140, please refer to other parts of this specification (e.g., Figure 2 (and its description), which will not be repeated here.

[0037] In some embodiments, the crystal preparation apparatus 100 may further include a power component (not shown) for driving the lifting component 130 to rotate and / or move up and down, thereby driving the seed crystal holder 131 or seed crystal A to rotate and / or move up and down, so as to grow crystals. In some embodiments, the power component may include, but is not limited to, an electric drive device, a hydraulic drive device, a pneumatic drive device, or any combination thereof, and this specification does not limit this.

[0038] In some embodiments, the crystal preparation apparatus 100 may further include a heat-insulating component 150 for heat-insulating the growth chamber 110. In some embodiments, the heat-insulating component 150 may be disposed around the outer periphery of the growth chamber 110. In some embodiments, the material of the heat-insulating component 150 may include quartz (silicon oxide), corundum (alumina), zirconium oxide, carbon fiber, ceramics, or other high-temperature resistant materials (e.g., rare earth metal borides, carbides, nitrides, silicides, phosphides, and sulfides).

[0039] In some embodiments, the crystal preparation apparatus 100 may further include a furnace body 160. In some embodiments, the furnace body 160 may be disposed outside the growth chamber 110, the heating component 120, and the heat preservation component 150.

[0040] In some embodiments, such as Figure 1 As shown, the upper part of the growth chamber 110, the heat preservation component 150 and the furnace body 160 are provided with through holes so that the lifting component 130 and / or the guide component 140 can pass through to rotate and / or move up and down.

[0041] In some embodiments, the crystal fabrication apparatus 100 may further include an observation component 170 (e.g., an observation window). The observation component 170 allows for real-time observation of the crystal growth within the growth chamber 110. In some embodiments, such as Figure 1 As shown, the observation component 170 can be located on the upper wall of the furnace body 160.

[0042] In some embodiments, the crystal preparation apparatus 100 may further include a sensing component 180. In some embodiments, the sensing component 180 may be used to monitor crystal growth-related information (e.g., temperature information, pulling speed and / or rotation speed of the pulling component 130, liquid level position information, crystal appearance (e.g., size)). In some embodiments, the sensing component 180 may be located on the upper wall of the furnace body 160. In some embodiments, the sensing component 180 may include a temperature sensing element, a speed sensing element, a liquid level sensor (e.g., a radar probe, a radar level gauge), an image acquisition device, etc.

[0043] In some embodiments, the temperature sensing component can be used to measure temperature information within the growth chamber 110. In some embodiments, the temperature sensing component may include an infrared thermometer, a photoelectric pyrometer, a fiber optic radiation thermometer, a colorimetric thermometer, an ultrasonic thermometer, or any combination thereof.

[0044] In some embodiments, the speed sensing component may be used to measure the lifting speed (e.g., rising speed, falling speed) and / or rotational speed of the lifting assembly 130.

[0045] In some embodiments, the liquid level sensor can be used to measure the liquid surface position information and / or liquid surface height information of the melt in the growth chamber 110.

[0046] In some embodiments, the image acquisition device may include an infrared imaging device, an X-ray imaging device, an ultrasonic imaging device, or any combination thereof.

[0047] In some embodiments, the crystal fabrication apparatus 100 may further include a processing component (not shown). In some embodiments, the processing component may receive crystal growth-related information sent by the sensing component 180, and control other components of the crystal fabrication apparatus 100 (e.g., heating component 120, lifting component 130, guiding component 140, power component) based on the crystal growth-related information to ensure normal crystal growth. For example, the processing component may control the lifting speed and / or rotation speed of the lifting component 130 based on liquid level position information and / or liquid level height information to control at least a portion of the guiding component 140 (e.g., Figure 2 The immersion rate and / or immersion amount of the raw material melt in the cylinder 141 shown are used to maintain a constant liquid level in the raw material melt. For example, the processing component can control the power component based on the pulling speed and / or rotation speed of the pulling component 130 to ensure that the pulling speed and / or rotation speed of the pulling component 130 meets the requirements of each stage of crystal growth. For example, the processing component can control the heating power and / or position of the heating component 120 based on temperature information within the growth chamber 110 to maintain a stable temperature field.

[0048] In some embodiments, the processing component may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), an application-specific instruction set processor (ASIP), a graphics processing unit (GPU), a physical processing unit (PPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), a programmable logic device (PLD), a controller, a microcontroller unit, a reduced instruction set computer (RISC), a microprocessor, or any combination thereof.

[0049] In some embodiments, the crystal preparation apparatus 100 may further include a display component (not shown in the figure). In some embodiments, the display component may display crystal growth-related information in real time (e.g., temperature information, lifting speed and / or rotation speed of the lifting component 130, liquid level position information, crystal appearance, etc.).

[0050] In some embodiments, the display component may include a liquid crystal display, a plasma display, a light-emitting diode display, or any combination thereof.

[0051] In some embodiments, the crystal preparation apparatus 100 may further include a storage component (not shown). The storage component may store data, instructions, and / or any other information. In some embodiments, the storage component may store data and / or information involved in the crystal preparation process. For example, the storage component may store temperature information, liquid level information, and / or data and / or instructions used to complete the exemplary crystal preparation methods described in the embodiments of this specification.

[0052] In some embodiments, the storage component may include a USB flash drive, a portable hard drive, an optical disc, a memory card, or any combination thereof.

[0053] It should be noted that the above description of the crystal preparation apparatus 100 is for illustrative purposes only and does not limit the scope of this specification. Those skilled in the art can make various modifications and changes to the crystal preparation apparatus 100 under the guidance of this specification. However, these modifications and changes are still within the scope of this specification.

[0054] Figure 2 This is a schematic diagram of the structure of an exemplary lifting component and a guiding component according to some embodiments of this specification.

[0055] In some embodiments, such as Figure 2As shown, the guiding component 140 may include a cylinder 141 and a transmission mechanism 142. In some embodiments, the transmission mechanism 142 may be driveably connected to the cylinder 141 to realize the up-and-down movement of the cylinder 141. In some embodiments, the transmission mechanism 142 may also be driveably connected to the lifting component 130 (e.g., the lifting rod 132). In some embodiments, the lifting component 130 and the transmission mechanism 142 may be driven to move, further driving the up-and-down movement of the cylinder 141. In some embodiments, during crystal growth, the lifting component 130, the cylinder 141, and the transmission mechanism 142 may be driveably connected to each other and / or drive each other to control growth parameters (e.g., temperature field, liquid level position, and / or height) during crystal growth.

[0056] Specifically, for example, Figures 3-7 This is a schematic diagram illustrating exemplary heating and material preparation stages, crystal pulling stages, Czochralski growth stages, and growth termination stages according to some embodiments of this specification. Figure 3 As shown, before the material is heated and melted (i.e., the raw material melts into a molten substance), the lifting assembly 130 and the guiding assembly 140 move in a transmission motion with each other, such that during the heating and melting stage, the lifting rod 132 is at least partially located inside the cylinder 141, and the seed crystal holder 131 is located inside the cylinder 141 and above the raw material. Figure 4 As shown, during the crystal pulling stage, the pulling assembly 130 moves downwards (e.g., Figure 4 As shown by arrow a), the cylinder 141 can be driven to move upward through the transmission mechanism 142 (as shown by arrow a). Figure 4 (As shown by the middle arrow b). Figure 5 and Figure 6 As shown, during the lifting growth stage, the lifting component 130 moves upward (e.g., Figure 5 and Figure 6 As shown by arrow d), the cylinder 141 can be driven to move downwards via the transmission mechanism 142 (as shown by arrow d). Figure 5 and Figure 6 (As indicated by the middle arrow e). Figure 7 As shown, at the end of the growth phase, the lifting component 130 moves upward (e.g., Figure 7 As shown by arrow f, the cylinder 141 can be driven to move downwards via the transmission mechanism 142 (as shown by arrow f). Figure 7 (As indicated by the middle arrow g).

[0057] Generally, during the growth of silicon carbide crystals, the silicon component is volatile, causing the volatilized silicon vapor to move and adhere to the insulation component, thus damaging its insulation performance. Accordingly, in the embodiments of this specification, by introducing a cylinder 141 (especially a trapezoidal cylinder that is wider at the top and narrower at the bottom), the volatilized silicon vapor can adhere to the side wall of the cylinder 141, thereby preventing the silicon vapor from moving to the insulation component 150 and ensuring the insulation performance and service life of the insulation component 150.

[0058] Furthermore, silicon vapor easily adheres to the surface of the seed crystal, leading to spontaneous nucleation. The introduction of the cylinder 141 in the embodiments of this specification can protect and / or insulate the seed crystal and / or the growing crystal. Since crystal growth takes place inside the cylinder 141, the temperature field distribution around the growing crystal can be improved, reducing internal thermal stress and correspondingly preventing the pulled-out crystal from cracking due to extreme cold.

[0059] Furthermore, during crystal growth, as the crystal is pulled and grown, the melt level gradually decreases, leading to significant temperature fluctuations near the surface and the formation of impurity inclusions within the crystal. The introduction of the cylinder 141 (and the transmission mechanism 142) in this embodiment allows the cylinder 141 to gradually immerse itself in the melt as the crystal grows, dynamically adjusting the melt level position and / or height to maintain basic stability. In addition, the silicon adhering to the sidewall of the cylinder 141 can provide silicon compensation to the melt, thereby mitigating melt component segregation caused by silicon volatilization. Furthermore, the cylinder 141 can act as a heat reflector, reducing the supersaturation of the melt surface and preventing spontaneous nucleation and formation of floating crystals on the melt surface.

[0060] In some embodiments, the material of the cylinder 141 may include graphite, which can provide the raw material carbon required for the preparation of silicon carbide crystals.

[0061] In some embodiments, the diameter of the cylinder 141 can be along the direction from the bottom to the top of the cylinder 141 (e.g., Figure 2 (As indicated by the middle arrow) Gradually increases in size. In some embodiments, the cylinder 141 may be a trapezoidal cylinder.

[0062] In some embodiments, the thickness of the cylinder 141 and the angle between its sidewall and the horizontal plane can affect the melt level and temperature field during crystal growth, thereby affecting the temperature field and crystal quality. For example, if the thickness of the cylinder 141 is too small or the angle between its sidewall and the horizontal plane is too large, less portion of the cylinder 141 will be immersed in the raw material melt as the lifting assembly 130 is raised during crystal growth. This will not effectively replenish the melt consumed during crystal growth, and will also fail to effectively guarantee the temperature field and stable melt level required for crystal growth. Conversely, if the thickness of the cylinder 141 is too large or the angle between its sidewall and the horizontal plane is too small, more portion of the cylinder 141 will be immersed in the raw material melt during crystal growth, which will also fail to effectively guarantee a stable melt level.

[0063] In some embodiments, during the pull growth stage, the angle between the sidewall of the cylinder 141 and the horizontal plane also affects the distance between the seed crystal or the growing crystal and the sidewall of the cylinder 141, affecting the radial growth rate of the crystal, and further affecting the crystal diameter expansion growth and the crystal shoulder angle.

[0064] Therefore, in some embodiments, the thickness of the cylinder 141 and the angle between the side wall of the cylinder 141 and the horizontal plane must meet preset requirements.

[0065] In some embodiments, the thickness of the cylinder 141 can be in the range of 1mm-3mm. In some embodiments, the thickness of the cylinder 141 can be in the range of 1.2mm-2.8mm. In some embodiments, the thickness of the cylinder 141 can be in the range of 1.4mm-2.6mm. In some embodiments, the thickness of the cylinder 141 can be in the range of 1.6mm-2.4mm. In some embodiments, the thickness of the cylinder 141 can be in the range of 1.8mm-2.2mm. In some embodiments, the thickness of the cylinder 141 can be in the range of 1.9mm-2mm.

[0066] In some embodiments, the angle between the sidewall of cylinder 141 and the horizontal plane can be in the range of 100°-140°. In some embodiments, the angle between the sidewall of cylinder 141 and the horizontal plane can be in the range of 105°-135°. In some embodiments, the angle between the sidewall of cylinder 141 and the horizontal plane can be in the range of 110°-130°. In some embodiments, the angle between the sidewall of cylinder 141 and the horizontal plane can be in the range of 115°-125°. In some embodiments, the angle between the sidewall of cylinder 141 and the horizontal plane can be in the range of 118°-120°.

[0067] In some embodiments, the sidewall of the cylinder 141 may be provided with a through hole 1411. During crystal growth, the through hole 1411 can serve as a transport channel between the melt inside the cylinder 141 and the melt outside.

[0068] In some embodiments, the shape of the through hole 1411 may include regular or irregular shapes such as circles, ellipses, polygons, and stars. In some embodiments, the shapes of the through holes 1411 may be the same or different.

[0069] In some embodiments, the diameter and density of the through-holes 1411 affect the transport process, thereby affecting the quality of the grown crystal. For example, if the diameter or density of the through-holes 1411 is too small, the transport efficiency between the melt inside and outside the cylinder 141 will be low. Alternatively, if the diameter of the through-holes 1411 is too large, it cannot effectively prevent floating crystals from entering the interior of the cylinder 141, affecting crystal quality. Or, if the density of the through-holes 1411 is too high, volatile silicon vapor will move through the through-holes 1411 located above the melt to the interior of the cylinder 141 and deposit on the crystal surface, affecting crystal quality. Therefore, in some embodiments, the diameter and density of the through-holes 1411 need to meet preset requirements.

[0070] In some embodiments, the diameter of the through hole 1411 can be in the range of 0.5mm-2mm. In some embodiments, the diameter of the through hole 1411 can be in the range of 0.7mm-1.8mm. In some embodiments, the diameter of the through hole 1411 can be in the range of 0.9mm-1.6mm. In some embodiments, the diameter of the through hole 1411 can be in the range of 1.1mm-1.4mm. In some embodiments, the diameter of the through hole 1411 can be in the range of 1.2mm-1.3mm.

[0071] In some embodiments, the density of the through holes 1411 can be expressed as the number of through holes 1411 per unit area. In some embodiments, the density of the through holes 1411 can be 3 holes / cm². 2 -10 pieces / cm 2 Within the range. In some embodiments, the density of through holes 1411 can be 4 holes / cm². 2 -9 pieces / cm 2 Within the range. In some embodiments, the density of through holes 1411 can be 5 holes / cm². 2 -8 pieces / cm 2 Within the range. In some embodiments, the density of through holes 1411 can be 6 holes / cm². 2 -7 pieces / cm 2 Within the range.

[0072] In some embodiments, the distance between the through-hole 1411 and the bottom of the cylinder 141 affects the crystal growth process and / or crystal quality. For example, if the distance between the through-hole 1411 and the bottom of the cylinder 141 is too short, during the heating and melting stage (e.g., as...), Figure 3 As shown), at least a portion of the through-hole 1411 is located below or near the seed crystal. Vaporized silicon vapor can enter the interior of the cylinder 141 through this portion of the through-hole 1411 and deposit on the surface of the seed crystal, thus affecting crystal quality. For example, if the distance between the through-hole 1411 and the bottom of the cylinder 141 is too long, the through-hole 1411 cannot effectively penetrate the melt during crystal growth, thus hindering effective melt transport and further affecting crystal quality. Therefore, in some embodiments, the distance between the through-hole 1411 and the bottom of the cylinder 141 needs to meet a preset requirement. In the embodiments of this specification, the distance between the through-hole 1411 and the bottom of the cylinder 141 can be understood as the distance between the lowest through-hole 1411' and the bottom of the cylinder 141 (e.g., ...). Figure 2 (as shown in h).

[0073] In some embodiments, the distance between the through hole 1411 and the bottom of the cylinder 141 can be in the range of 3mm-10mm. In some embodiments, the distance between the through hole 1411 and the bottom of the cylinder 141 can be in the range of 3.5mm-9.5mm. In some embodiments, the distance between the through hole 1411 and the bottom of the cylinder 141 can be in the range of 4mm-9mm. In some embodiments, the distance between the through hole 1411 and the bottom of the cylinder 141 can be in the range of 4.5mm-8.5mm. In some embodiments, the distance between the through hole 1411 and the bottom of the cylinder 141 can be in the range of 5mm-8mm. In some embodiments, the distance between the through hole 1411 and the bottom of the cylinder 141 can be in the range of 5.5mm-7.5mm. In some embodiments, the distance between the through hole 1411 and the bottom of the cylinder 141 can be in the range of 6mm-7mm.

[0074] In some embodiments, graphite paper 1412 may be disposed at the bottom of the cylinder 141. During the heating and material preparation stage (e.g., as...), Figure 3 As shown), graphite paper 1412 can block volatile silicon vapor (e.g., Figure 3 (As shown by "C") is attached to the seed crystal (e.g., Figure 3 As shown in "A" in the diagram, this further ensures the quality of crystal growth. During the crystallization stage (e.g., as shown in the diagram), Figure 4 As shown), by the descent of the lifting component 130 (as shown) Figure 4 (As shown by the middle arrow a) and the rise of the guide assembly 140 (e.g., cylinder 141) (as shown by the middle arrow a) Figure 4 As indicated by the middle arrow b), the seed crystal can be gradually brought closer to the graphite paper 1412 and gently touched to cause it to fall into the melt. The graphite paper 1412 can dissolve in the melt to provide the raw material carbon required for the preparation of silicon carbide crystals without introducing any additional contamination.

[0075] In some embodiments, the shape of the graphite paper 1412 may be adapted to the shape of the bottom of the cylinder 141. For example, if the bottom of the cylinder 141 is circular, the graphite paper 1412 may also be circular. In some embodiments, the diameter of the graphite paper 1412 may be slightly larger than the bottom diameter of the cylinder 141. Accordingly, during the heating and melting stage, the graphite paper 1412 may remain at the bottom of the cylinder 141 and not fall off automatically; while during the crystallization stage, the graphite paper 1412 may be gently touched to fall into the melt.

[0076] In some embodiments, the diameter of the graphite paper 1412 may be greater than the bottom diameter of the tube 141 by approximately 0.5 mm to 1 mm. In some embodiments, the diameter of the graphite paper 1412 may be greater than the bottom diameter of the tube 141 by approximately 0.6 mm to 0.9 mm. In some embodiments, the diameter of the graphite paper 1412 may be greater than the bottom diameter of the tube 141 by approximately 0.7 mm to 0.8 mm.

[0077] In some embodiments, the thickness of the graphite paper 1412 can affect the crystal growth process and further affect the crystal quality. For example, if the thickness of the graphite paper 1412 is too small, during the heating and melting stage, the volatilized silicon vapor will cause the graphite paper 1412 to move upward or drift, resulting in the volatilized silicon vapor moving through the gap between the graphite paper 1412 and the inner wall of the cylinder 141 to the top of the graphite paper 1412 and adhering to the surface of the seed crystal, affecting the crystal quality. Conversely, if the thickness of the graphite paper 1412 is too large, the time it takes for the graphite paper 1412 to melt in the melt will be longer, further affecting the stability of the melt surface and the crystal growth process. Therefore, in some embodiments, the thickness of the graphite paper 1412 needs to meet a preset requirement.

[0078] In some embodiments, the thickness of the graphite paper 1412 can be in the range of 100 μm-300 μm. In some embodiments, the thickness of the graphite paper 1412 can be in the range of 120 μm-280 μm. In some embodiments, the thickness of the graphite paper 1412 can be in the range of 140 μm-260 μm. In some embodiments, the thickness of the graphite paper 1412 can be in the range of 160 μm-240 μm. In some embodiments, the thickness of the graphite paper 1412 can be in the range of 180 μm-220 μm. In some embodiments, the thickness of the graphite paper 1412 can be in the range of 200 μm-210 μm.

[0079] In some embodiments, a top cover may be provided on the top of the cylinder 141 to reduce the temperature gradient above the crystal, maintain a stable temperature field, and improve crystal quality. In some embodiments, the top cover may include a through hole to allow the lifting assembly 130 to pass through the through hole for lifting movement. In some embodiments, the shape of the top cover may be adapted to the shape of the top of the cylinder 141. For example, if the top of the cylinder 141 is circular, the top cover may also be circular. In some embodiments, the material of the top cover may include, but is not limited to, graphite.

[0080] In some embodiments, such as Figure 2 As shown, the transmission mechanism 142 may include a connecting ring 1421, a connecting member 1422, a rotating shaft 1423, and a stop block 1424.

[0081] In some embodiments, a portion of the connecting ring 1421 may be located on the top sidewall of the cylinder 141. In some embodiments, a portion of the connecting ring 1421 may also be located on the lifting assembly 130 (e.g., the lifting rod 132).

[0082] In some embodiments, the number of connecting rings 1421 may be 3, 4, 5, etc. In some embodiments, the multiple connecting rings 1421 located on the top sidewall of the cylinder 141 may be evenly distributed to maintain the stability of the cylinder 141 as much as possible when the cylinder 141 moves up and down, and further ensure the stability of the melt surface.

[0083] In some embodiments, connector 1422 may be used to connect connecting ring 1421 located on the top sidewall of cylinder 141 to connecting ring 1421 located on lifting assembly 130, so as to connect cylinder 141 and lifting assembly 130 (e.g., lifting rod 132).

[0084] In some embodiments, the rotating shaft 1423 may be located on a support on the upper part of the growth chamber 110 or on the furnace body 160. For example, the rotating shaft 1423 may be fixed to a support frame 1425 provided on the furnace body 160. In some embodiments, the rotating shaft 1423 may include, but is not limited to, a fixed pulley.

[0085] In some embodiments, the connector 1422 may pass through the pivot 1423 to connect the connecting ring 1421 located on the top sidewall of the cylinder 141 to the connecting ring 1421 located on the lifting assembly 130, so that the lifting assembly 130 (e.g., the lifting rod 132) moves in the opposite direction to the cylinder 141. For example, during the crystal pulling stage, the lifting assembly 130 moves downward (e.g., ...). Figure 4 When the middle arrow (a) is pointed out, the cylinder 141 will move upward (as shown by the middle arrow a). Figure 4 (As shown by arrow b), so that the seed crystal A gradually approaches the graphite paper 1412. For example, during the pull-growth stage, when the pull assembly 130 (e.g., pull rod 132) moves upward (as shown by arrow b), the seed crystal A gradually approaches the graphite paper 1412. Figure 5 and Figure 6 When the arrow d is pointed out, the cylinder 141 will move downwards (as shown by the middle arrow d). Figure 5 and Figure 6 (As shown by the middle arrow e), it is immersed in the melt to replenish the melt portion consumed by crystal growth, and further maintain the stability of the melt level.

[0086] In some embodiments, the stop 1424 may be located on the connector 1422. In some embodiments, the stop 1422 may be located on the connector 1422 near the connecting ring 1421 on the lifting assembly 130. In some embodiments, "near" may refer to the connector 1422 within a preset distance from the connecting ring 1421 on the lifting assembly 130. In some embodiments, the preset distance may include, but is not limited to, 10cm, 8cm, 6cm, 4cm, 2cm, 1cm, etc. In some embodiments, the stop 1424 may cooperate with the rotating shaft 1423 to block the movement of the connector 1422. For example, as Figure 7 As shown, after crystal growth is complete, the lifting assembly 130 continues to move upward (e.g., ...). Figure 7 When (as indicated by the middle arrow f), the stop block 1424 can be locked at the rotating shaft 1423 to prevent the cylinder 141 from continuing to descend and melting into the melt.

[0087] In some embodiments, the crystal fabrication apparatus 100 may further include a support assembly, a driving assembly, and a temperature measuring assembly (collectively referred to as the "temperature measuring device"). Further description can be found in other parts of this specification (e.g., Figure 8 (and its description), which will not be repeated here.

[0088] Figure 8 This is a schematic diagram of an exemplary temperature measuring device according to some embodiments of this specification. In some embodiments, the temperature measuring device 800 can be used to measure the temperature associated with the growth chamber 110. In some embodiments, the temperature measuring device 800 can be used to determine the position of the high-temperature line. In some embodiments, the temperature measuring device 800 can also move the growth chamber 110 so that the melt surface is located at the high-temperature line position to improve crystal quality. The temperature measuring device 800 involved in the embodiments of this specification will be described in detail below with reference to the accompanying drawings, taking the preparation of silicon carbide crystals as an example. It is worth noting that the following embodiments are merely illustrative of this specification and do not constitute a limitation thereof.

[0089] like Figure 8 As shown, the temperature measuring device 800 may include a support assembly 810, a drive assembly 820, and a temperature measuring assembly 830.

[0090] In some embodiments, the support component 810 may be disposed below the growth chamber 110 to support the growth chamber 110. In some embodiments, the support component 810 may be fixedly connected to the growth chamber 110. For example, one end of the support component 810 may be connected to the outer bottom of the growth chamber 110 via a threaded clamp. In some embodiments, the support component 810 may be at least partially located within the furnace body 160.

[0091] In some embodiments, the drive component 820 can be used to drive the support component 810 to move up and down, so as to further drive the growth cavity 110 to move up and down.

[0092] In some embodiments, the drive assembly 820 may include a fixed component 821, a lead screw 822, and a power component 823.

[0093] In some embodiments, the fixing member 821 can be used to fix the support assembly 810 and connect the support assembly 810 and the lead screw 822. For example, the fixing member 821 can be welded to the support assembly 810. In some embodiments, the fixing member 821 can be drivenly connected to the lead screw 822 (e.g., threaded connection). In some embodiments, the fixing member 821 can be provided with internal threads, and the lead screw 822 can be provided with external threads, and the connection between the two is achieved through the cooperation of the internal and external threads.

[0094] In some embodiments, the power component 823 can provide power to the lead screw 822. For example, the power component 823 can drive the lead screw 822 to rotate, and the lead screw 822 can drive the fixing component 821 and the support assembly 810 to move up and down, and further drive the growth chamber to move up and down.

[0095] In some embodiments, the temperature measuring component 830 can be used to measure the temperature within the growth chamber 110 (e.g., the temperature at the melt surface). In some embodiments of this specification, the temperature measuring component is... Figure 1 The temperature sensing component of the crystal preparation apparatus 100 may refer to the same or similar components or parts.

[0096] In some embodiments, the temperature measuring device 800 may further include a processing component. This processing component may be the same as the processing component of the crystal preparation apparatus 100, or it may be a separate processing component.

[0097] In some embodiments, the processing component can receive temperature information from the temperature measurement component 830 within the growth chamber 110, and determine the high-temperature line position (the position with the highest temperature or a horizontal position within the growth chamber 110) based on the temperature information. For example, if the temperature at a specific position above the melt surface measured by the temperature measurement component 830 is higher than the temperature at any other position (e.g., any position other than that specific position), the processing component can determine that the specific position above the melt surface is the high-temperature line position. As another example, if the temperature at a specific position below the melt surface measured by the temperature measurement component 830 is higher than the temperature at any other position (e.g., any position other than that specific position), the processing component can determine that the specific position below the melt surface is the high-temperature line position. As yet another example, if the melt surface temperature measured by the temperature measurement component is higher than the temperature at other positions within the growth chamber (e.g., any position above or below the melt surface), the processing component can determine that the melt surface is located at the high-temperature line position.

[0098] In some embodiments, the processing component can also compare the melt surface temperature with the temperature at other locations (above or below the melt surface) when the growth chamber is located at different positions.

[0099] In some embodiments, the processing component can control the drive component 820 to drive the support component 810 to move up and down based on the high-temperature line position, so that the growth chamber 110 moves to the position where the melt surface is located at the high-temperature line, thereby growing a high-quality crystal (e.g., without inclusions or other defects). For example, if the high-temperature line is located at a specific position above the melt surface, the processing component can control the drive component 820 to drive the support component 810 to move upward, so that the growth chamber 110 moves upward to the position where the melt surface is located. As another example, if the high-temperature line is located at a specific position below the melt surface, the processing component can control the drive component 820 to drive the support component 810 to move downward, so that the growth chamber 110 moves downward to the position where the melt surface is located.

[0100] Figure 9 This is a flowchart illustrating an exemplary crystal fabrication method according to some embodiments of this specification. This process 900 can be performed by one or more components in a crystal fabrication apparatus (e.g., crystal fabrication apparatus 100). In some embodiments, process 900 can be performed automatically by a control system. For example, process 900 can be implemented by control commands, based on which the control system controls the various components to complete the various operations of process 900. In some embodiments, process 900 can be performed semi-automatically. For example, one or more operations of process 900 can be performed manually by an operator. In some embodiments, when completing process 900, one or more additional operations not described may be added, and / or one or more operations discussed herein may be removed. Additionally, Figure 9 The order of operations shown is not restrictive. Figure 9 As shown, process 900 includes the following steps.

[0101] Step 910: Place the raw material into the growth chamber (e.g., growth chamber 110).

[0102] In some embodiments, the raw material may refer to the raw materials required for crystal growth. For example, when growing silicon carbide crystals, the raw material may include silicon (e.g., silicon powder, silicon wafers, silicon blocks), and the growth chamber (e.g., a graphite chamber) itself may serve as a carbon source. As another example, when growing silicon carbide crystals, the raw material may include both silicon and carbon (e.g., carbon powder, carbon blocks, carbon particles), meaning that an additional carbon source can be provided, thereby increasing the lifespan of the growth chamber. In some embodiments, the raw material may also include a flux to improve the solubility of carbon in silicon. In some embodiments, the flux may include, but is not limited to, aluminum, silicon-chromium alloys, Li-Si alloys, Ti-Si alloys, Fe-Si alloys, Sc-Si alloys, and Co-Si alloys. For a more detailed description of the growth chamber, please refer to other parts of this specification (e.g., Figure 1 (and related descriptions), which will not be repeated here.

[0103] Step 920: The lifting assembly (e.g., lifting assembly 130) with the seed crystal attached is lowered to the vicinity of the raw material.

[0104] In some embodiments, a lifting assembly with seed crystals attached can be driven downward by a power component to bring it down to the vicinity of the raw material. In some embodiments, "vicinity" can refer to a preset distance from the upper surface of the raw material. In some embodiments, the preset distance can include, but is not limited to, 10cm, 8cm, 6cm, 4cm, 2cm, 1cm, 0.5cm, 0.3cm, 0.1cm, etc.

[0105] In some embodiments, the lifting assembly is drivenly connected to a guide assembly (e.g., guide assembly 140), and the lifting assembly is at least partially located within the guide assembly (e.g., within the cylinder 141).

[0106] For descriptions of the lifting assembly, guiding assembly, power assembly, etc., please refer to other parts of this manual (e.g., Figure 1 , Figure 2 (and its description), which will not be repeated here.

[0107] Step 930: Heat the growth chamber to form the raw material melt.

[0108] In some embodiments, the growth chamber can be heated by a heating component (e.g., heating component 130) to melt the raw material and form a raw material melt. For example, when growing silicon carbide crystals, the raw material melts to form a solution of carbon in silicon, which serves as the liquid raw material for crystal growth.

[0109] In some embodiments, such as Figure 3 As shown, during the process of raw material melting to form a raw material melt (heating and material processing stage), the seed crystal can be located below the through hole 1411 on the side wall of the cylinder 141. Accordingly, even if silicon vapor (e.g., as...) Figure 3 As shown in "C", the silicon vapor can enter the interior of the cylinder 141 through the through hole 1411. Since the seed crystal is located below the through hole 1411, silicon vapor will not be deposited on the surface of the seed crystal (e.g., the seeding surface), which can protect the seed crystal seeding surface and avoid spontaneous nucleation of the seed crystal in the subsequent seeding stage.

[0110] In some embodiments, during the heating and melting stage, the distance between the bottom of the cylinder 141 or the graphite paper at its bottom and the molten surface can be within a first preset range. In some embodiments, the graphite paper at the bottom of the cylinder 141 can contact the seed crystal's guiding surface, but there is no interaction force between them. In some embodiments, the distance between the bottom of the cylinder 141 or the graphite paper at its bottom and the molten surface affects the crystal quality. For example, if the distance between the bottom of the cylinder 141 or the graphite paper at its bottom and the molten surface is too small, the graphite paper 1412 may melt during the heating and melting stage, preventing it from protecting the seed crystal's guiding surface, thus affecting the seed crystal quality and consequently the crystal quality. As another example, if the distance between the bottom of the cylinder 141 or the graphite paper at its bottom and the molten surface is too large, during the subsequent pulling growth stage, the upward movement of the pulling assembly cannot bring the cylinder 141 into contact with the melt, causing the cylinder 141 to fail to prevent the floating crystal from entering the crystal growth interface, thus affecting the crystal quality. Therefore, in some embodiments, the distance between the bottom of the cylinder 141 or the graphite paper at its bottom and the molten surface needs to be within a first preset range.

[0111] In some embodiments, the first preset range may be in the range of 5mm-10mm. In some embodiments, the first preset range may be in the range of 6mm-9mm. In some embodiments, the first preset range may be in the range of 7mm-8mm.

[0112] In some embodiments, the melt surface can be positioned at the high temperature line using a temperature measuring device (e.g., temperature measuring device 800) to grow high-quality crystals (e.g., free of inclusions and other defects).

[0113] In some embodiments, the position of the growth chamber can be adjusted by a temperature measuring device (e.g., temperature measuring device 800), and the melt surface temperature in the growth chamber at different positions can be compared to position the growth chamber at the position with the highest melt surface temperature (i.e., the melt surface is at the high temperature line). For example, the melt surface temperature (which can be denoted as "T0") at the current position (which can be denoted as "S0") of the growth chamber can be measured by a temperature measuring component. Starting from the current position S0 of the growth chamber, the processing component can control the driving component to drive the support component to move upward, so that the growth chamber moves upward by a first preset distance range to a first position, and the melt surface temperature (which can be denoted as "T1") of the growth chamber at the first position can be measured by the temperature measuring component. Starting from the current position S0 of the growth chamber, the processing component can also control the driving component to drive the support component to move downward, so that the growth chamber moves downward by a first preset distance range to a second position, and the melt surface temperature (which can be denoted as "T2") of the growth chamber at the second position can be measured by the temperature measuring component. Comparing T0, T1, and T2, if the temperature difference between T0 and T1 or between T0 and T2 is greater than a preset temperature difference range, the growth chamber position with the highest temperature (which can be denoted as "Tmax1") is selected as the initial position for the second adjustment of the growth chamber (which can be denoted as "S1"). In some embodiments, the preset temperature difference range may be no greater than 0.5℃, no greater than 1℃, no greater than 2℃, etc.

[0114] Starting from the initial position S1 of the second adjustment, the processing component can control the driving component to drive the support component to move upward or downward respectively, so that the growth chamber moves upward or downward by a second preset distance range to the third or fourth position. The temperature measuring component then measures the melt surface temperature T3 and T4 of the growth chamber at the third and fourth positions respectively. Tmax1, T3, and T4 are compared. If Tmax1 is greater than T3, Tmax1 is greater than T4, and the temperature differences between Tmax1 and T3 and between Tmax1 and T4 are not greater than a preset temperature difference range, the melt surface position where Tmax1 is located is the high-temperature line position. If the temperature difference between Tmax1 and T3 or between Tmax1 and T4 is greater than the preset temperature difference range, the growth chamber position with the highest temperature (which can be marked as "Tmax2") is selected as the initial position for the third adjustment of the growth chamber (which can be marked as "S2"). This process is repeated to determine that the melt surface position with the highest temperature is the high-temperature line position, and the melt surface is located at the high-temperature line position at this time.

[0115] In some embodiments, the first preset distance may be no less than the second preset distance. In some embodiments, the first preset distance may be greater than the second preset distance to improve the efficiency of determining the high-temperature line.

[0116] In some embodiments, the position of the high-temperature line can be determined by a temperature measuring device (e.g., temperature measuring device 800), and the growth chamber can be further moved to bring the melt surface to the high-temperature line position. In some embodiments, the temperature information within the growth chamber can be measured by a temperature measuring component and sent to a processing component. In some embodiments, the processing component can determine the position of the high-temperature line based on the temperature information and drive the support component to move by a driving component, thereby further driving the growth chamber to move so that the melt surface is brought to the high-temperature line position. For example, if the temperature at a specific location above the melt surface measured by the temperature measuring component is higher than the temperature at any other location (e.g., any location other than the specific location), the processing component can control the driving component to drive the support component to move upward, so that the growth chamber moves upward until the melt surface is brought to the specific location. As another example, if the temperature at a specific location below the melt surface measured by the temperature measuring component is higher than the temperature at any other location (e.g., any location other than the specific location), the processing component can control the driving component to drive the support component to move downward, so that the growth chamber moves downward until the melt surface is brought to the specific location. For example, if the temperature of the melt surface measured by the temperature measuring component is higher than the temperature at other locations within the growth chamber (e.g., any location above or below the melt surface), then the melt surface is determined to be located at the high temperature line.

[0117] For a description of the temperature measuring device, please refer to other parts of this manual (e.g., Figure 8 (and its description), which will not be repeated here.

[0118] Step 940: Crystals are grown based on seed crystals and raw material melts through the transmission movement of the lifting component and the guiding component.

[0119] In some embodiments, such as Figure 4 As shown, during the crystal pulling stage, the lifting assembly 130 can be driven downwards by the power assembly (e.g., Figure 4 (As shown by the middle arrow a), causing the guide assembly 140 (e.g., cylinder 141) to move upward (as shown by the middle arrow a). Figure 4 As indicated by arrow b), the seed crystal can gradually approach the graphite paper set at the bottom of cylinder 141. Continuing the movement, the seed crystal can gently touch the graphite paper, causing it to fall into the melt.

[0120] In some embodiments, such as Figure 5 and Figure 6 As shown, during the lifting and growth stage, the lifting component 130 can be rotated and moved upwards by the power component (e.g., Figure 5 and Figure 6 (As indicated by the middle arrow d), causing the guide assembly 140 (e.g., cylinder 141) to move downwards (as shown by the middle arrow d). Figure 5 and Figure 6(As indicated by arrow e), the melt can enter the bottom of cylinder 141 and solidify at the seed crystal to grow crystals.

[0121] In some embodiments, such as Figure 6 As shown, during the crystal growth process based on seed crystal and raw material melt (Czochralski stage), at least a portion of the through-hole 1411 on the sidewall of cylinder 141 can be located in the melt. The through-hole 1411 can serve as a transport channel between the melt inside cylinder 141 and the melt outside.

[0122] As mentioned earlier, as the Czochralski growth process proceeds, some of the melt is consumed, and the melt level gradually decreases, leading to significant temperature fluctuations near the surface and the formation of impurity inclusions within the crystal. Accordingly, in some embodiments, a sensing component can monitor crystal growth-related information and send this information to a processing component. Based on this information, the processing component can control the pulling speed and / or rotation speed of the Czochralski component to control the immersion rate and / or amount of the tube into the raw material melt, thereby maintaining a constant melt level. For example, a level sensor can measure the melt level position and / or height information within the growth chamber during crystal growth and send this information to the processing component. When the consumption of some melt causes the melt level to fall below the initial melt level, the processing component can calculate the melt consumption rate and / or consumption amount based on the melt level position information and / or melt level height information. Furthermore, it can calculate the lifting speed of the lifting component based on the thickness of the cylinder and the angle between its sidewall and the horizontal plane, so that the immersion rate of the cylinder into the melt is equal to the melt consumption rate and / or the immersion amount of the cylinder into the melt is equal to the melt consumption amount, thereby maintaining a constant melt level, a stable temperature field, and ensuring normal crystal growth.

[0123] It should be noted that the above description of process 900 is for illustrative purposes only and does not limit the scope of this specification. Those skilled in the art can make various modifications and changes to process 900 under the guidance of this specification. However, these modifications and changes remain within the scope of this specification.

[0124] Example 1

[0125] Silicon and flux, the raw materials for SiC crystal growth, are placed in the growth chamber, and a crystal preparation apparatus is assembled. A lifting assembly with a seed crystal attached is lowered to the vicinity of the raw materials using a power component. The growth chamber is heated by a heating component, melting the raw materials to form a melt. During the heating and melting stage, the distance between the graphite paper at the bottom of the cylinder or its base and the melt surface is in the range of 5mm-10mm. After melting, the distance between the seed crystal's guiding surface and the melt surface is in the range of 6mm-12mm. The lifting assembly is lowered using the power component, causing the seed crystal to touch the graphite paper, which then falls into the melt. After a preset time (e.g., 0.5h), the seed crystal contacts the melt and begins crystal growth.

[0126] After the seed crystal has been in contact with the melt for 10-30 minutes, the lifting assembly is rotated and moved upwards by the power component to grow the crystal. During the upward movement of the lifting assembly, the barrel descends until it is partially immersed and dissolved in the melt. During the lifting growth stage, the sensing component monitors crystal growth-related information and sends this information to the processing component. Based on the crystal growth-related information, the processing component controls the lifting speed and / or rotation speed of the lifting assembly to control the immersion rate and / or immersion amount of the barrel in the raw material melt, thereby maintaining a constant liquid level in the raw material melt.

[0127] When the stop on the connector moves to the graphite shaft, the stop is locked, and the cylinder stops descending, at which point the lifting growth stage ends. The lifting assembly is then moved upwards by the power unit, separating the crystal from the melt to obtain inclusion-free SiC crystals.

[0128] The beneficial effects that the embodiments of this specification may bring include, but are not limited to: (1) Through the transmission movement of the lifting component and the guiding component, the crystal growth is carried out in the cylinder of the guiding component, which improves the temperature field and keeps the melt surface stable during the growth process, thereby improving the crystal quality. (2) The diameter of the cylinder gradually increases from the bottom to the top of the cylinder. During the crystal growth process, the volatilized silicon vapor will move upward to the side wall of the cylinder, which will prevent the volatilized silicon vapor from moving to the heat insulation component, thus ensuring the heat insulation performance and service life of the heat insulation component. Furthermore, during the lifting growth stage, as the lifting component is lifted, the cylinder will descend to a point where it is partially immersed in the melt. The silicon attached to the side wall of the cylinder can compensate for the silicon in the melt and reduce the segregation of melt components. At the same time, the cylinder can act as a heat reflector, which can reduce the supersaturation of the melt surface and prevent spontaneous nucleation of floating crystals on the melt surface. (3) During the lifting growth stage, as the lifting component is lifted, part of the cylinder will be immersed in the melt. The through holes on the side wall of the cylinder are immersed in the melt. The through holes can serve as a transmission channel between the melt inside the cylinder and the melt outside the cylinder. The through holes can also prevent floating crystals outside the cylinder from entering the cylinder, thus maintaining stable crystal growth. (4) Graphite paper is provided at the bottom of the cylinder. During the heating and material preparation stage, the graphite paper can prevent the volatilized silicon vapor from adhering to the surface of the seed crystal, which can further ensure the quality of crystal growth. During the crystal pulling stage, the seed crystal can gently touch the graphite paper to make it fall into and dissolve in the melt, so as to provide the raw material carbon required for the preparation of silicon carbide crystals. (5) The processing component can control the pulling speed and / or rotation speed of the pulling component based on crystal growth-related information (e.g., liquid level information) to control the immersion speed and / or immersion amount of the cylinder into the raw material melt, so as to maintain a constant liquid level of the raw material melt, maintain a stable temperature field, ensure normal crystal growth, and improve crystal quality. It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects that may be produced can be any one or a combination of the above, or any other possible beneficial effects.

[0129] 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 specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0130] Furthermore, this specification uses specific terms to describe embodiments thereof. 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 this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0131] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0132] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, 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 a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0133] For each patent, patent application, patent application publication, and other material, such as articles, books, specifications, publications, and documents, referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials to this specification and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0134] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and are considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. A method for preparing a crystal, characterized in that, The method includes: Place the raw materials into the growth chamber; The lifting assembly with the seed crystal attached is lowered to the vicinity of the raw material, wherein, The lifting assembly is drivenly connected to the guiding assembly, the guiding assembly includes a cylinder, and the lifting assembly is at least partially located inside the cylinder; The diameter of the cylinder gradually increases from the bottom to the top of the cylinder; The side wall of the cylinder is provided with a through hole; Heating the growth chamber to form a raw material melt; and Crystals are grown based on the seed crystal and the raw material melt through the transmission motion of the lifting assembly and the guiding assembly.

2. The crystal preparation method according to claim 1, characterized in that, During the process of melting the raw material to form the raw material melt, the seed crystal is located below the through hole.

3. The crystal preparation method according to claim 1, characterized in that, During the crystal growth process based on the seed crystal and the raw material melt, at least a portion of the through-hole is located in the raw material melt.

4. The crystal preparation method according to claim 1, characterized in that, During the process of melting the raw material to form the raw material melt, the distance between the bottom of the cylinder and the surface of the melt is within a first preset range.

5. The crystal preparation method according to claim 1, characterized in that, Graphite paper is provided at the bottom of the cylinder. During the process of melting the raw material to form the raw material melt, the distance between the graphite paper and the melt surface is within a first preset range.

6. The crystal preparation method according to claim 5, characterized in that, Through the transmission motion of the lifting assembly and the guiding assembly, crystals are grown based on the seed crystal and the raw material melt, comprising: Control the downward movement of the lifting assembly and the upward movement of the cylinder to bring the seed crystal close to the graphite paper and cause the graphite paper to fall into and dissolve in the raw material melt.

7. The crystal preparation method according to claim 1, characterized in that, Through the transmission motion of the lifting assembly and the guiding assembly, crystals are grown based on the seed crystal and the raw material melt, comprising: By controlling the lifting speed of the lifting assembly, the immersion speed and / or immersion amount of the cylinder into the raw material melt are controlled to maintain a constant liquid level in the raw material melt.

8. The crystal preparation method according to claim 1, characterized in that, During the crystal growth process based on the seed crystal and the raw material melt, the growth chamber is moved to keep the melt surface at the high temperature line position.

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