CN116334744A

CN116334744A - Crystal preparation method

Info

Publication number: CN116334744A
Application number: CN202310339328.5A
Authority: CN
Inventors: 王宇; 顾鹏; 梁振兴; 李敏
Original assignee: Meishan Boya New Material Co ltd
Current assignee: Meishan Boya New Material Co ltd
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2023-06-27
Also published as: CN115044964A; CN115044964B

Abstract

The embodiment of the specification provides a crystal preparation method. The preparation method of the crystal comprises the following steps: placing the raw materials into a growth cavity; lowering the seed crystal-bonded pulling assembly to the vicinity of the feedstock, wherein the pulling assembly is in driving connection with a guide assembly comprising a barrel, the pulling assembly being at least partially located within the barrel; heating the growth chamber to form a feedstock melt; by the driving motion of the pulling assembly and the guiding assembly, crystals are grown based on the seed crystal and the melt of the raw material.

Description

Crystal preparation method

Description of the division

The present application is a divisional application filed in China with the name of "a seed crystal preparation device" and having a filing date of 2022, month 07 and 19, a filing number of 202210847948.5.

Technical Field

The specification relates to the technical field of crystal preparation, in particular to a device and a method for preparing crystals based on a liquid phase method.

Background

When crystals (e.g., silicon carbide) are prepared based on a liquid phase method (e.g., top-seed flux method (TSSG)), the segregation of the melt components, spontaneous nucleation at the seed surface or melt level, etc. are easily caused due to the fact that a part of the components (e.g., silicon) in the raw materials are volatile at high temperatures. In addition, the change of the temperature field is caused by the change of the melt liquid level in the lifting growth process, so that the normal growth of crystals is affected. Accordingly, there is a need for an improved crystal production apparatus and method that ensures proper crystal growth.

Disclosure of Invention

One of the embodiments of the present specification provides a crystal preparation apparatus. The crystal preparation device comprises: the growth cavity is used for placing raw materials; a heating assembly for heating the growth chamber; the lifting assembly is used for lifting and growing; and the guide assembly comprises a cylinder, the lifting assembly is at least partially positioned inside the cylinder, and the lifting assembly is in transmission connection with the guide assembly.

In some embodiments, the diameter of the barrel increases gradually in a bottom-to-top direction of the barrel.

In some embodiments, the thickness of the cartridge is in the range of 1mm-3 mm.

In some embodiments, the sidewall of the cartridge is angled from horizontal in the range of 100 ° -140 °.

In some embodiments, the sidewall of the cartridge is provided with a through hole.

In some embodiments, the diameter of the through hole is in the range of 0.5mm-2 mm.

In some embodiments, the through hole is in a distance from the bottom of the cartridge in a range of 3mm-10 mm.

In some embodiments, the density of the through holes is 3/cm ² -10/cm ² Within the range.

In some embodiments, the bottom of the cartridge is provided with graphite paper.

In some embodiments, the guide assembly further comprises a drive mechanism drivingly connected to the barrel to effect up and down movement of the barrel.

Drawings

The present specification will be further elucidated by way of example embodiments, which will be described in detail by means of the accompanying drawings. The embodiments are not limiting, in which like numerals represent like structures, wherein:

FIG. 1 is a schematic diagram of an exemplary crystal production apparatus according to some embodiments of the present disclosure;

FIG. 2 is a schematic structural view of an exemplary pull assembly and guide assembly shown in accordance with some embodiments of the present description;

FIG. 3 is a schematic diagram of an exemplary elevated temperature melting stage shown in accordance with some embodiments of the present description;

FIG. 4 is a schematic diagram of an exemplary seeding stage shown in accordance with some embodiments of the present description;

FIG. 5 is a schematic diagram of an exemplary pull-up growth stage shown in accordance with some embodiments of the present description;

FIG. 6 is a schematic diagram of an exemplary pull-up growth stage according to further embodiments of the present description;

FIG. 7 is a schematic diagram of an exemplary end of crystal growth shown in accordance with some embodiments of the present disclosure;

FIG. 8 is a schematic diagram of an exemplary temperature measurement device shown in accordance with some embodiments of the present disclosure;

fig. 9 is a flow chart of an exemplary crystal preparation method according to some embodiments of the present description.

In the figure, 100 is a crystal preparation device, 110 is a growth cavity, 120 is a heating component, 130 is a lifting component, 131 is a seed crystal support, 132 is a lifting rod, 140 is a guiding component, 141 is a cylinder, 1411 is a through hole, 1411' is a through hole at the lowest end, 1412 is graphite paper, 142 is a transmission mechanism, 1421 is a connecting ring, 1422 is a connecting piece, 1423 is a rotating shaft, 1424 is a stop block, 1425 is a supporting frame, 150 is a heat preservation component, 160 is a furnace body, 170 is an observation component, 180 is a sensing component, 800 is a temperature measurement device, 810 is a supporting component, 820 is a driving component, 821 is a fixing component, 823 is a screw rod, 823 is a power component, and 830 is a temperature measurement component.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present specification, the drawings that are required to be used in the description of the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some examples or embodiments of the present specification, and it is possible for those of ordinary skill in the art to apply the present specification to other similar situations according to the drawings without inventive effort. Unless otherwise apparent from the context of the language or otherwise specified, like reference numerals in the figures refer to like structures or operations.

It will be appreciated that "system," "apparatus," "unit" and/or "module" as used herein is one method for distinguishing between different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

As used in this specification and the claims, the terms "a," "an," "the," and/or "the" are not specific to a singular, but may include a plurality, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that the steps and elements are explicitly identified, and they do not constitute an exclusive list, as other steps or elements may be included in a method or apparatus.

FIG. 1 is a schematic diagram of an exemplary crystal production apparatus according to some embodiments of the present disclosure.

In some embodiments, crystal production apparatus 100 may be based on a liquid phase process to produce crystals (e.g., silicon carbide). The crystal production apparatus 100 according to the embodiment in the specification will be described in detail below with reference to the accompanying drawings, taking as an example the production of silicon carbide crystals. It is noted that the following examples are only for explanation of the present specification and are not to be construed as limiting the present specification.

As shown in fig. 1, crystal preparation apparatus 100 may include a growth chamber 110, a heating assembly 120, a pulling assembly 130, and a guiding assembly 140.

The growth chamber 110 may serve as a place for crystal preparation. The heating assembly 120 may be used to heat the growth chamber 110 to provide the heat (e.g., temperature field, etc.) required for crystal preparation.

In some embodiments, the material of the growth chamber 110 may be determined according to the type of crystal to be prepared. For example, in preparing silicon carbide crystals, the material of growth chamber 110 may include graphite. Graphite may be used as a carbon source to provide the carbon necessary to produce silicon carbide crystals. In some embodiments, the material of the growth chamber 110 may also include molybdenum, tungsten, tantalum, and the like. In some embodiments, the growth chamber 110 may house the raw materials (e.g., silicon powder, carbon powder) needed to prepare the crystal. In some embodiments, growth chamber 110 may be a location where the feedstock melts to form a melt. For example, under the high temperature generated by heating assembly 120, the silicon powder melts into a melt (liquid state), and the carbon provided by growth chamber 110 itself dissolves in the silicon solution to form a solution of carbon in silicon as a liquid feedstock for the liquid phase process for preparing silicon carbide crystals. In some embodiments, to increase the solubility of carbon in silicon, fluxing agents (e.g., aluminum, silicon chromium alloys, li-Si alloys, ti-Si alloys, fe-Si alloys, sc-Si alloys, co-Si alloys, etc.) may be added to the feedstock.

In some embodiments, the heating assembly 120 may include an induction heating assembly, a resistance heating assembly, or the like. In some embodiments, the heating assembly 120 may be disposed around the periphery of the growth chamber 110. In some embodiments, as shown in fig. 1, the heating assembly 120 may include an induction coil. In some embodiments, an induction coil may be disposed around the outer perimeter of growth chamber 110.

In some embodiments, the pulling assembly 130 may move up and down and/or rotate to perform pulling growth. In some embodiments, as shown in FIG. 1, the pull assembly 130 may include a seed holder 131 and a pull rod 132. In some embodiments, a seed crystal (e.g., as shown by "A" in FIG. 1) may be bonded to the lower surface of the seed holder 131. In some embodiments, a lift rod 132 may be coupled to the seed holder 131 to move and/or rotate the seed holder 131 up and down.

In some embodiments, the guide assembly 140 may be drivingly connected to the lift assembly 130. In some embodiments, the guide assembly 140 may be in driving motion with the pull assembly 130. For a description of the pulling assembly 130 and the guiding assembly 140, reference may be made to other portions of the present specification (e.g., fig. 2 and the description thereof), and no further description is given here.

In some embodiments, crystal growing apparatus 100 may further include a power assembly (not shown) for rotating and/or moving up and down pulling assembly 130 to rotate and/or move up and down seed holder 131 or seed A to grow the crystal. In some embodiments, the power assembly may include, but is not limited to, an electric drive, a hydraulic drive, a pneumatic drive, and the like, or any combination thereof, as this description is not limited in this regard.

In some embodiments, crystal production apparatus 100 may further comprise a soak assembly 150 for holding growth chamber 110. In some embodiments, the insulating assembly 150 may be disposed around the periphery of the growth chamber 110. In some embodiments, the insulating component 150 may comprise quartz (silica), corundum (alumina), zirconia, carbon fiber, ceramic, etc., or other refractory materials (e.g., borides, carbides, nitrides, silicides, phosphides, sulfides, etc. of rare earth metals).

In some embodiments, crystal production apparatus 100 may further comprise furnace 160. In some embodiments, the furnace body 160 may be disposed outside the growth chamber 110, the heating assembly 120, and the insulating assembly 150.

In some embodiments, as shown in fig. 1, the growth chamber 110, the insulating assembly 150, and the upper portion of the furnace body 160 are provided with holes therethrough to enable the pulling assembly 130 and/or the guiding assembly 140 to pass therethrough for rotation and/or up-and-down movement.

In some embodiments, crystal production apparatus 100 may further include a viewing assembly 170 (e.g., a viewing window). By viewing assembly 170, crystal growth within growth chamber 110 may be observed in real time. In some embodiments, as shown in FIG. 1, the viewing assembly 170 may be located on the upper wall of the furnace body 160.

In some embodiments, crystal production apparatus 100 may also include a sensing assembly 180. In some embodiments, the sensing assembly 180 may be used to monitor crystal growth related information (e.g., temperature information, pull rate and/or rotational speed of the pull assembly 130, level position information, crystal appearance (e.g., size)). In some embodiments, the sensing assembly 180 may be located on the upper wall of the furnace body 160. In some embodiments, the sensing assembly 180 may include a temperature sensing component, a speed sensing component, a level sensor (e.g., radar gauge, radar level gauge), an image acquisition device, and the like.

In some embodiments, a temperature sensing component may be used to measure temperature information within 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 the like, or any combination thereof.

In some embodiments, the speed sensing component may be used to measure the pull speed (e.g., the rise speed, the fall speed) and/or the rotation speed of the pull assembly 130.

In some embodiments, a level sensor may be used to measure level position information and/or level height information of the melt within growth chamber 110.

In some embodiments, the image acquisition device may include an infrared imaging device, an X-ray imaging device, an ultrasound imaging device, or the like, or any combination thereof.

In some embodiments, crystal production apparatus 100 may also include processing components (not shown). In some embodiments, the processing component may receive the crystal growth related information sent by the sensing component 180 and control other components of the crystal preparation apparatus 100 (e.g., the heating component 120, the pulling component 130, the guiding component 140, the power component) based on the crystal growth related information to ensure proper crystal growth. For example, the processing assembly may control the pull rate and/or rotational speed of the pull assembly 130 to control the immersion rate and/or the immersion amount of at least a portion of the components of the guide assembly 140 (e.g., the cartridge 141 shown in fig. 2) into the raw material melt based on the liquid level position information and/or the liquid level height information to maintain a constant liquid level of the raw material melt. For another example, the processing assembly may control the power assembly based on the pulling speed and/or rotational speed of the pulling assembly 130 such that the pulling speed and/or rotational speed of the pulling assembly 130 meets the needs of the various stages of crystal growth. For another example, the processing assembly may control the heating power of the heating assembly 120 and/or the position of the heating assembly 120 based on temperature information within the growth chamber 110 to maintain a steady temperature field.

In some embodiments, the processing components may include a Central Processing Unit (CPU), an Application Specific Integrated Circuit (ASIC), an application specific instruction set processor (ASIP), an image processor (GPU), a physical arithmetic 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 the like, or any combination thereof.

In some embodiments, crystal production apparatus 100 may further include a display assembly (not shown). In some embodiments, the display assembly may display crystal growth related information (e.g., temperature information, pull rate and/or rotational speed of the pull assembly 130, level position information, crystal appearance) and the like in real time.

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

In some embodiments, crystal production 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 related to the crystal preparation process. For example, the memory component may store temperature information, liquid level position information, and/or data and/or instructions related to the crystal preparation process to accomplish the exemplary crystal preparation methods described in the embodiments of the specification.

In some embodiments, the storage component may include a U disk, a removable hard disk, an optical disk, a memory card, etc., or any combination thereof.

It should be noted that the above description of the crystal production apparatus 100 is for illustration and description only, and does not limit the scope of applicability of the present description. Various modifications and variations of crystal production apparatus 100 will be apparent to those skilled in the art in light of the present description. However, such modifications and variations are still within the scope of the present description.

Fig. 2 is a schematic structural view of an exemplary pulling assembly and guide assembly shown in accordance with some embodiments of the present description.

In some embodiments, as shown in fig. 2, the guide assembly 140 may include a barrel 141 and a drive mechanism 142. In some embodiments, the drive mechanism 142 may be drivingly connected to the cartridge 141 to effect up and down movement of the cartridge 141. In some embodiments, the drive mechanism 142 may also be in driving connection with the lift assembly 130 (e.g., the lift rod 132). In some embodiments, the pulling assembly 130 and the transmission mechanism 142 can be driven to move, and further drive the cylinder 141 to move up and down. In some embodiments, during crystal growth, the pulling assembly 130, the cartridge 141, and the drive mechanism 142 may be drivingly connected and/or drivingly moved to each other to control growth parameters (e.g., temperature field, level position, and/or height) during crystal growth.

Specifically, for example, fig. 3-7 are schematic diagrams of exemplary warming chemistry phases, seeding phases, pull growth phases, and growth end phases shown in accordance with some embodiments of the present description. As shown in fig. 3, prior to warming up the charge (i.e., melting the raw material into a melt), the pull rod assembly 130 and the guide assembly 140 are in driving motion with each other such that the pull rod 132 is at least partially positioned within the barrel 141 during the warming up stage, and the seed holder 131 is positioned within the barrel 141 and above the raw material. As shown in fig. 4, during the seeding stage, the pulling assembly 130 moves downward (as indicated by arrow a in fig. 4), and the drum 141 can be driven to move upward (as indicated by arrow b in fig. 4) by the transmission mechanism 142. As shown in fig. 5 and 6, during the pull-up growth phase, the pull assembly 130 moves upward (as indicated by arrow d in fig. 5 and 6) and the cartridge 141 may be driven downward (as indicated by arrow e in fig. 5 and 6) by the drive mechanism 142. As shown in fig. 7, at the end of growth stage, the pulling assembly 130 moves upward (as indicated by arrow f in fig. 7), and the drum 141 can be driven downward (as indicated by arrow g in fig. 7) by the transmission mechanism 142.

Generally, during the growth of silicon carbide crystals, the volatile silicon vapor moves and adheres to the insulation assembly due to the volatile silicon component, deteriorating the insulation performance of the insulation assembly. Accordingly, in the embodiment of the present specification, by introducing the cylinder 141 (particularly, a trapezoid cylinder with a wide upper part and a narrow lower part), the volatilized silicon vapor can be attached to the sidewall of the cylinder 141, thereby preventing the silicon vapor from moving to the heat-insulating assembly 150, and ensuring the heat-insulating performance and the service life of the heat-insulating assembly 150.

In addition, silicon vapor also easily adheres to the seed crystal surface, resulting in spontaneous nucleation. While the introduction of the cartridge 141 in the present embodiment may provide protection and/or insulation to the seed crystal and/or the growing crystal. Since crystal growth is performed inside the barrel 141, the temperature field distribution around the grown crystal can be improved, the thermal stress inside the crystal can be reduced, and cracking of the crystal pulled out by hands due to extreme coldness can be prevented accordingly.

Further, during the crystal growth process, as the crystal is pulled up and grown, the melt level gradually decreases, resulting in a significant fluctuation of the temperature field near the level, and the inclusion of impurities in the crystal. While the introduction of the cartridge 141 (and the actuator 142) in the present embodiment allows the cartridge 141 to be immersed in the melt gradually as the crystal grows, the level position and/or height is dynamically adjusted to maintain a substantially stable level. In addition, silicon attached to the sidewall of the barrel 141 can compensate silicon for the melt, thereby reducing segregation of the melt components caused by volatilization of silicon. Further, the cylinder 141 can act as a heat reflecting screen, and can reduce the supersaturation of the melt liquid level, so as to avoid spontaneous nucleation on the melt surface to form floating crystals.

In some embodiments, the material of the cartridge 141 may include graphite, which may provide the raw carbon required to produce silicon carbide crystals.

In some embodiments, the diameter of the cartridge 141 may gradually increase in a bottom-to-top direction of the cartridge 141 (as indicated by the arrow in fig. 2). In some embodiments, the cartridge 141 may be a trapezoidal cartridge.

In some embodiments, the thickness of barrel 141 and the angle of its sidewall to the horizontal may affect the melt level, temperature field, etc. during crystal growth, which in turn affects the temperature field and crystal quality of the crystal growth. For example, too small a thickness of the barrel 141 or too large an angle between the side wall of the barrel 141 and the horizontal plane may result in less portions of the barrel 141 immersed in the raw material melt as the pulling assembly 130 is lifted during crystal growth, an inability to effectively supplement the melt consumed for crystal growth, and an inability to effectively ensure a temperature field and a stable liquid level required for crystal growth. For another example, too large a thickness of the barrel 141 or too small an angle between the side wall of the barrel 141 and the horizontal plane may result in more portions of the barrel 141 immersed in the raw material melt during crystal growth, and also may not be effective in ensuring a stable liquid level.

In some embodiments, the angle of the sidewall of the barrel 141 to the horizontal during the pull-up growth phase also affects the distance between the seed crystal or growing crystal and the sidewall of the barrel 141, affects the radial growth rate of the crystal, and further affects the expanded growth of the crystal and the crystal's shoulder angle.

Accordingly, in some embodiments, the thickness of the barrel 141 and the angle between the sidewall of the barrel 141 and the horizontal plane are required to satisfy the predetermined requirement.

In some embodiments, the thickness of the cartridge 141 may be in the range of 1mm-3 mm. In some embodiments, the thickness of the cartridge 141 may be in the range of 1.2mm-2.8 mm. In some embodiments, the thickness of the cartridge 141 may be in the range of 1.4mm-2.6 mm. In some embodiments, the thickness of the cartridge 141 may be in the range of 1.6mm-2.4 mm. In some embodiments, the thickness of the cartridge 141 may be in the range of 1.8mm-2.2 mm. In some embodiments, the thickness of the cartridge 141 may be in the range of 1.9mm-2 mm.

In some embodiments, the sidewall of the barrel 141 may be angled from horizontal in the range of 100 ° -140 °. In some embodiments, the sidewall of the barrel 141 may be angled from horizontal in the range of 105 ° -135 °. In some embodiments, the sidewall of the barrel 141 may be angled from horizontal in the range of 110 ° -130 °. In some embodiments, the sidewall of the barrel 141 may be angled from horizontal in the range of 115 ° -125 °. In some embodiments, the sidewall of the barrel 141 may be angled from horizontal in the range of 118 ° -120 °.

In some embodiments, the sidewall of the cartridge 141 may be provided with a through hole 1411. The through-hole 1411 may serve as a transfer channel between the melt inside the barrel 141 and the external melt during crystal growth.

In some embodiments, the shape of the through-holes 1411 may include regular or irregular shapes such as circles, ovals, polygons, stars, and the like. In some embodiments, the shape of the through holes 1411 may be the same or different.

In some embodiments, the diameter and density of the vias 1411 affect the transport process, which in turn affects the quality of the grown crystals. For example, too small a diameter or density of through holes 1411 may result in lower melt transfer efficiency from the interior to the exterior of the barrel 141. For another example, the diameter of the through hole 1411 is too large to effectively block the floating crystal from entering the inside of the drum 141, affecting the crystal quality. As another example, where the density of the through holes 1411 is too high, volatilized silicon vapors may migrate through the through holes 1411 above the melt to the interior of the barrel 141 and deposit on the crystal surface, affecting the crystal quality. Thus, in some embodiments, the diameter and density of the vias 1411 are required to meet predetermined requirements.

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

In some embodiments, the density of the vias 1411 may be expressed as the number of vias 1411 per unit area. In some embodiments, the density of vias 1411 may be at 3/cm ² -10/cm ² Within the range. In some embodiments, the density of vias 1411 may be at 4/cm ² -9/cm ² Within the range. In some embodiments, the density of vias 1411 may be at 5/cm ² -8/cm ² Within the range.In some embodiments, the density of vias 1411 may be at 6/cm ² -7/cm ² Within the range.

In some embodiments, the distance of the through-hole 1411 from the bottom of the barrel 141 can affect the crystal growth process and/or the crystal quality. For example, if the distance between the through-hole 1411 and the bottom of the barrel 141 is too short, at least a portion of the through-hole 1411 may be located below or near the seed during the elevated temperature melting phase (e.g., as shown in fig. 3), and volatilized silicon vapor may enter the interior of the barrel 141 through this portion of the through-hole 1411 and deposit on the surface of the seed, thereby affecting the crystal quality. Also for example, the distance between the through hole 1411 and the bottom of the barrel 141 is too long, and during crystal growth, the through hole 1411 cannot be effectively immersed in the melt, so that effective melt transfer cannot be achieved, and further crystal quality is affected. Thus, in some embodiments, the distance of the through hole 1411 from the bottom of the cartridge 141 needs to meet a predetermined requirement. In the present embodiment, the distance of the through hole 1411 from the bottom of the cylinder 141 can be understood as the distance of the lowermost through hole 1411' from the bottom of the cylinder 141 (as shown in h of fig. 2).

In some embodiments, the through hole 1411 may be in the range of 3mm-10mm from the bottom of the cartridge 141. In some embodiments, the distance of the through hole 1411 from the bottom of the cartridge 141 may be in the range of 3.5mm-9.5 mm. In some embodiments, the through hole 1411 may be in the range of 4mm-9mm from the bottom of the cartridge 141. In some embodiments, the distance of the through hole 1411 from the bottom of the cartridge 141 may be in the range of 4.5mm-8.5 mm. In some embodiments, the through hole 1411 may be in the range of 5mm-8mm from the bottom of the cartridge 141. In some embodiments, the distance of the through hole 1411 from the bottom of the cartridge 141 may be in the range of 5.5mm-7.5 mm. In some embodiments, the through hole 1411 may be in the range of 6mm-7mm from the bottom of the cartridge 141.

In some embodiments, the bottom of the cartridge 141 may be provided with graphite paper 1412. In the temperature rising and melting stage (e.g., as shown in fig. 3), the graphite paper 1412 can block the volatilized silicon vapor (e.g., "C" in fig. 3) from adhering to the surface of the seed crystal (e.g., "a" in fig. 3), and further can ensure the crystal growth quality. During the seeding stage (e.g., as shown in fig. 4), the seed crystal may be brought closer to the graphite paper 1412 and gently touch the graphite paper 1412 to drop into the melt by the lowering of the pulling assembly 130 (as shown by arrow a in fig. 4) and the raising of the guide assembly 140 (e.g., barrel 141) (as shown by arrow b in fig. 4). Graphite paper 1412 may be dissolved in the melt to provide the raw carbon necessary to produce silicon carbide crystals without introducing any additional contamination.

In some embodiments, the shape of the graphite paper 1412 may conform to the shape of the bottom of the cartridge 141. For example, the bottom of the cylinder 141 may be circular in shape, and the graphite paper 1412 may be circular in shape. In some embodiments, the diameter of the graphite paper 1412 may be slightly larger than the bottom diameter of the cartridge 141, and accordingly, during the warming and melting stage, the graphite paper 1412 may be located at the bottom of the cartridge 141 and not automatically fall off; while in the seeding stage, the graphite paper 1412 may be lightly touched to fall into the melt.

In some embodiments, the diameter of the graphite paper 1412 may be in the range of about 0.5mm-1mm greater than the diameter of the bottom of the cartridge 141. In some embodiments, the diameter of the graphite paper 1412 may be in the range of about 0.6mm-0.9mm greater than the diameter of the bottom of the cartridge 141. In some embodiments, the diameter of the graphite paper 1412 may be in the range of about 0.7mm-0.8mm greater than the diameter of the bottom of the cartridge 141.

In some embodiments, the thickness of the graphite paper 1412 may affect the crystal growth process, further affecting the crystal quality. For example, the thickness of the graphite paper 1412 is too small, and during the temperature-rising melting stage, the volatilized silicon vapor may cause the graphite paper 1412 to move upward or drift, resulting in the volatilized silicon vapor moving over the graphite paper 1412 through the gap between the graphite paper 1412 and the inner wall of the barrel 141 and adhering to the seed crystal surface, affecting the quality of the crystal. For another example, if the thickness of the graphite paper 1412 is too large, the graphite paper 1412 may melt in the melt for a longer period of time, further affecting the stability of the melt level and affecting the crystal growth process. Thus, in some embodiments, the thickness of the graphite paper 1412 needs to meet preset requirements.

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

In some embodiments, the top of the cartridge 141 may be provided with a top cover to reduce the temperature gradient over the crystal, maintain a stable temperature field, and improve crystal quality. In some embodiments, the top cover may include a through hole such that the pulling assembly 130 may be pulled through the through hole. In some embodiments, the shape of the top cover may conform to the top shape of the cartridge 141. For example, the top of the cartridge 141 may be circular in shape and the top cap may be circular in shape. In some embodiments, the material of the top cover may include, but is not limited to, graphite.

In some embodiments, as shown in fig. 2, the transmission 142 may include a connection ring 1421, a connection member 1422, a shaft 1423, and a stop 1424.

In some embodiments, a portion of the connecting ring 1421 may be located at the top sidewall of the cartridge 141. In some embodiments, a portion of the attachment ring 1421 may also be located on the lift assembly 130 (e.g., the lift rod 132).

In some embodiments, the number of connection rings 1421 may be 3, 4, 5, etc. In some embodiments, the plurality of connecting rings 1421 at the top sidewall of barrel 141 may be evenly distributed to maintain barrel 141 as stable as possible during up and down movement of barrel 141, further ensuring melt level stability.

In some embodiments, a connector 1422 may be used to connect the connector ring 1421 at the top sidewall of the cartridge 141 with the connector ring 1421 on the pull assembly 130 to connect the cartridge 141 with the pull assembly 130 (e.g., the pull rod 132).

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

In some embodiments, the connection 1422 may pass through the rotation shaft 1423, connecting the connection ring 1421 at the top sidewall of the cartridge 141 with the connection ring 1421 on the pull assembly 130, such that the direction of movement of the pull assembly 130 (e.g., the pull rod 132) is opposite to the cartridge 141. For example, during the seeding stage, the pull assembly 130 moves downward (as indicated by arrow a in FIG. 4) and the drum 141 moves upward (as indicated by arrow b in FIG. 4) to bring the seed crystal A closer to the graphite paper 1412. For another example, during the pull growth phase, when the pull assembly 130 (e.g., pull rod 132) is moved upward (as indicated by arrow d in fig. 5 and 6), the barrel 141 is moved downward (as indicated by arrow e in fig. 5 and 6) to immerse the portion of the melt consumed by crystal growth, further maintaining the melt level stable.

In some embodiments, a stop 1424 may be located on the connection 1422. In some embodiments, the stop 1422 may be located on the connector 1422 proximate to the connector ring 1421 on the connection lift assembly 130. In some embodiments, proximate may refer to on the attachment 1422 within a predetermined distance from the attachment ring 1421 on the pull 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, a stop 1424 may cooperate with the shaft 1423 to block movement of the connector 1422. For example, as shown in FIG. 7, after crystal growth is completed, as pulling assembly 130 continues to move upward (as indicated by arrow f in FIG. 7), stop 1424 may catch on shaft 1423, preventing cartridge 141 from continuing to descend and melt.

In some embodiments, crystal production apparatus 100 may further include a support assembly, a drive assembly, and a temperature measurement assembly (which may be collectively referred to as a "temperature measurement apparatus"). For more description, reference may be made to other parts of the present specification (e.g., fig. 8 and description thereof), and no further description is given here.

Fig. 8 is a schematic diagram of an exemplary temperature measurement device according to some embodiments of the present description. In some embodiments, temperature measurement device 800 may be used to measure a temperature associated with growth chamber 110. In some embodiments, temperature measurement device 800 may be used to determine the location of a high temperature line. In some embodiments, temperature measurement device 800 may also move growth chamber 110 to place the melt level at a high temperature line position to improve crystal quality. The temperature measuring device 800 according to the embodiment in the specification will be described in detail below with reference to the accompanying drawings, taking silicon carbide crystal production as an example. It is noted that the following examples are only for explanation of the present specification and are not to be construed as limiting the present specification.

As shown in fig. 8, the temperature measuring device 800 may include a support assembly 810, a driving assembly 820, and a temperature measuring assembly 830.

In some embodiments, a support assembly 810 may be disposed below the growth chamber 110 for supporting the growth chamber 110. In some embodiments, the support assembly 810 may be fixedly connected to the growth chamber 110. For example, one end of the support assembly 810 and the outer bottom of the growth chamber 110 may be coupled by a screw clip. In some embodiments, the support assembly 810 may be located at least partially within the furnace body 160.

In some embodiments, the driving assembly 820 may be used to drive the supporting assembly 810 up and down to further drive the growth chamber 110 up and down.

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

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

In some embodiments, power component 823 may power lead screw 822. For example, the power unit 823 may drive the screw 822 to rotate, and the screw 822 may drive the fixing unit 821 and the supporting unit 810 to move up and down, and further may drive the growth chamber to move up and down.

In some embodiments, temperature measurement assembly 830 may be used to measure the temperature within growth chamber 110 (e.g., the temperature at the melt level). In some embodiments, in embodiments of the present disclosure, a temperature measurement component may refer to the same or similar components or parts as the temperature sensing components of crystal production apparatus 100 described in fig. 1.

In some embodiments, temperature measurement device 800 may also include a processing component. The processing unit may be the same as the processing unit of crystal production apparatus 100, or may be independent of each other.

In some embodiments, the processing component may receive temperature information within the growth chamber 110 sent by the temperature measurement component 830, and determine a high temperature line location (a location within the growth chamber 110 where the temperature is highest or a horizontal location) based on the temperature information. For example, if the temperature of a particular location above the melt level measured by temperature measurement component 830 is higher than the temperature of any other location (e.g., any location other than the particular location), the processing component may determine that the particular location above the melt level is a high temperature line location. For another example, if the temperature of a particular location below the melt level measured by temperature measurement component 830 is higher than the temperature of any other location (e.g., any location other than the particular location), the processing component may determine that the particular location below the melt level is a high temperature line location. For another example, if the temperature of the melt level measured by the temperature measurement assembly is higher than the temperature at other locations within the growth chamber (e.g., any location above or below the melt level), the processing assembly may determine that the melt level is at a high temperature line location.

In some embodiments, the processing assembly may also compare the melt level temperature with the temperature of other locations (locations above or below the melt level) when the growth chamber is located at a different location.

In some embodiments, the processing assembly may control the drive assembly 820 to drive the support assembly 810 up and down based on the hot line position to move the growth chamber 110 to a position where the melt level is at the hot line position, so that high quality crystals may be grown (e.g., without inclusions, etc.). For example, if the hot line position is at a particular location above the melt level, the processing assembly may control the drive assembly 820 to drive the support assembly 810 upward to move the growth chamber 110 upward to the melt level at that particular location. For another example, if the hot line position is at a particular location below the melt level, the processing assembly may control the drive assembly 820 to drive the support assembly 810 downward to move the growth chamber 110 downward to the melt level at that particular location.

Fig. 9 is a flow chart of an exemplary crystal preparation method according to some embodiments of the present description. The process 900 may be performed by one or more components in a crystal production apparatus (e.g., crystal production apparatus 100). In some embodiments, the process 900 may be performed automatically by a control system. For example, the flow 900 may be implemented by control instructions, based on which a control system controls various components to perform various operations of the flow 900. In some embodiments, the process 900 may be performed semi-automatically. For example, one or more operations of flow 900 may be performed manually by an operator. In some embodiments, upon completion of flow 900, one or more additional operations not described above may be added and/or one or more operations discussed herein may be pruned. In addition, the order of the operations shown in fig. 9 is not limiting. As shown in fig. 9, the process 900 includes the following steps.

At step 910, feedstock is placed within a growth chamber (e.g., growth chamber 110).

In some embodiments, the feedstock may refer to the feedstock material required to grow the crystal. For example, in growing silicon carbide crystals, the feedstock may include silicon (e.g., silicon powder, silicon wafer, silicon chunk), and the growth chamber (e.g., graphite chamber) itself may serve as the carbon source. For another example, in growing silicon carbide crystals, the feedstock may include silicon and carbon (e.g., carbon powder, carbon blocks, carbon particles), that is, a carbon source may be additionally provided, thereby increasing the useful life of the growth chamber. In some embodiments, the feedstock may also include a fluxing agent to increase the solubility of carbon in silicon. In some embodiments, the fluxing agent may include, but is not limited to, aluminum, silicon chromium alloys, li-Si alloys, ti-Si alloys, fe-Si alloys, sc-Si alloys, co-Si alloys. For a description of the growth chamber, reference may be made to other parts of the present specification (e.g., fig. 1 and its related description), and no further description is given here.

At step 920, the seed-bonded pulling assembly (e.g., pulling assembly 130) is lowered into proximity with the feedstock.

In some embodiments, the seed-bonded pulling assembly may be driven downward by a power assembly to lower it into proximity with the feedstock. In some embodiments, proximate may refer to within a predetermined distance from the upper surface of the feedstock. In some embodiments, the preset distance may include, but is not limited to, 10cm, 8cm, 6cm, 4cm, 2cm, 1cm, 0.5cm, 0.3cm, 0.1cm, etc.

In some embodiments, the pull assembly is drivingly connected to a guide assembly (e.g., guide assembly 140) and the pull assembly is at least partially located within the guide assembly (e.g., within cartridge 141).

For a description of the pulling assembly, the guiding assembly, the power assembly, etc., reference may be made to other parts of the present specification (e.g., fig. 1, 2 and descriptions thereof), and no further description is given here.

At 930, the growth chamber is heated to form a feedstock melt.

In some embodiments, the growth chamber may be heated by a heating assembly (e.g., heating assembly 130) to melt the feedstock to form a feedstock melt. For example, when growing silicon carbide crystals, the feedstock melts to form a solution of carbon in silicon as a liquid feedstock for crystal growth.

In some embodiments, as shown in fig. 3, during melting of the feedstock to form a feedstock melt (warming-up stage), a seed crystal may be located below the through-hole 1411 of the sidewall of the barrel 141. Accordingly, even though silicon vapor (e.g., as shown by "C" in fig. 3) may enter the interior of the drum 141 through the through-hole 1411, since the seed crystal is located under the through-hole 1411, the silicon vapor may not deposit on the surface of the seed crystal (e.g., seeding surface), and the seeding surface of the seed crystal may be protected from spontaneous nucleation during the subsequent seeding stage.

In some embodiments, during the warming-up chemistry phase, the distance of the graphite paper at the bottom of barrel 141 or its bottom from the melt level may be within a first preset range. In some embodiments, the graphite paper at the bottom of the cartridge 141 may be in contact with the seed crystal face, but without interaction forces therebetween. In some embodiments, the distance of the graphite paper at the bottom of barrel 141 or its bottom from the melt level can affect crystal quality. For example, the graphite paper at the bottom of the barrel 141 or its bottom is too small from the melt level, and during the warming and melting phase, the graphite paper 1412 may erode, resulting in the inability to protect the seeding surface, affecting the quality of the seed, and thus the quality of the crystal. For another example, the distance between the graphite paper at the bottom of the barrel 141 or its bottom and the melt level is too large, and the upward movement of the pulling assembly cannot bring the barrel 141 into contact with the melt during the subsequent pulling growth stage, resulting in the barrel 141 failing to prevent the floating crystals from entering the crystal growth interface, thereby affecting the crystal quality. Thus, in some embodiments, the distance of the graphite paper at the bottom of barrel 141 or its bottom from the melt level is within a first predetermined range.

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

In some embodiments, the melt level may be located at a high temperature line position by a temperature measurement device (e.g., temperature measurement device 800) to grow a high quality crystal (e.g., without inclusions, etc. defects).

In some embodiments, the position of the growth chamber may be adjusted by a temperature measurement device (e.g., temperature measurement device 800) and the melt level temperature in the growth chamber at different locations compared so that the growth chamber is at the location where the melt level temperature is highest (i.e., the melt level is at a high temperature line location). For example, the melt level temperature (which may be denoted as "T0") at the current position of the growth chamber (which may be denoted as "S0") may be measured by a temperature measurement assembly. Starting from the current position S0 of the growth chamber, the processing assembly may control the driving assembly to drive the supporting assembly to move upwards, so that the growth chamber moves upwards by a first preset distance range to a first position, and the temperature of the melt level of the growth chamber at the first position (may be denoted as "T1") is measured by the temperature measuring assembly. The processing component may further control the driving component to drive the supporting component to move downwards, starting from the current position S0 of the growth cavity, so as to enable the growth cavity to move downwards to a second position within a first preset distance range, and measure the melt level temperature (which may be represented as "T2") of the growth cavity at the second position through the temperature measuring component. Comparing T0, T1 and T2, if the temperature difference between T0 and T1 or the temperature difference between T0 and T2 is larger than the preset temperature difference range, selecting the growth cavity position with the highest temperature (the highest temperature can be expressed as Tmax 1) as the initial position of the second adjustment of the growth cavity (the initial position of the second adjustment can be expressed 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 ℃, and the like.

The processing component can control the driving component to drive the supporting component to move upwards or downwards respectively by taking the initial position S1 adjusted for the second time as a starting point, so that the growth cavity moves upwards or downwards by a second preset distance range to a third position or a fourth position, and the temperature measuring component is used for measuring the melt liquid level temperatures T3 and T4 of the growth cavity at the third position and the fourth position respectively. Tmax1, T3 and T4 were compared. If Tmax1 is greater than T3, tmax1 is greater than T4, the temperature difference between Tmax1 and T3, and the temperature difference between Tmax1 and T4 are not greater than the preset temperature difference range, the melt liquid level position where Tmax1 is located is the high temperature line position. If the temperature difference between Tmax1 and T3 or the temperature difference between Tmax1 and T4 is greater than the preset temperature difference range, the growth cavity position with the highest temperature (the highest temperature may be marked as "Tmax 2") is selected as the initial position of the third adjustment of the growth cavity (the initial position of the third adjustment may be marked as "S2"). By repeating the above steps, the position of the melt liquid level with the highest temperature can be determined as the position of the high temperature line, and the melt liquid level is positioned at the position of the high temperature line at the moment.

In some embodiments, the first preset distance may be not 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.

In some embodiments, the hot line position may also be determined by a temperature measurement device (e.g., temperature measurement device 800) and the growth chamber is further moved to position the melt level at the hot line position. In some embodiments, temperature information within the growth chamber may be measured by a temperature measurement assembly and the measured temperature information sent to a processing assembly. In some embodiments, the processing assembly may determine the position of the hot line based on the temperature information and drive the support assembly through the drive assembly to move to further drive the growth chamber to move with the melt level at the hot line position. For example, if the temperature at a particular location above the melt level measured by the temperature measurement assembly is higher than the temperature at any other location (e.g., any location other than the particular location), the processing assembly may control the drive assembly to drive the support assembly upward to move the growth chamber upward to a location where the melt level is at the particular location. For another example, if the temperature at a particular location below the melt level measured by the temperature measurement assembly is higher than the temperature at any other location (e.g., any location other than the particular location), the processing assembly may control the drive assembly to drive the support assembly downward to move the growth chamber downward to a location where the melt level is at the particular location. For another example, if the temperature of the melt level measured by the temperature measurement assembly is higher than the temperature at other locations within the growth chamber (e.g., any location above or below the melt level), then it is determined that the melt level is at a high temperature line location.

For a description of the temperature measuring device, reference may be made to other parts of the present specification (e.g., fig. 8 and description thereof), and a detailed description thereof will be omitted.

At 940, a crystal is grown based on the seed crystal and the melt of the feedstock by the driven motion of the pulling assembly and the guiding assembly.

In some embodiments, as shown in fig. 4, during the seeding stage, the power assembly may drive the pulling assembly 130 downward (as shown by arrow a in fig. 4) to move the guide assembly 140 (e.g., the drum 141) upward (as shown by arrow b in fig. 4), and the seed crystal may gradually approach the graphite paper disposed at the bottom of the drum 141. Continuing the movement, the seed crystal can lightly touch the graphite paper to drop into the melt.

In some embodiments, as shown in fig. 5 and 6, during the pull-up growth phase, the pull assembly 130 may be rotated and moved upward by the power assembly (as shown by arrow d in fig. 5 and 6), the guide assembly 140 (e.g., barrel 141) may be moved downward (as shown by arrow e in fig. 5 and 6), and the melt may enter the bottom of the barrel 141 and condense and crystallize at the seed crystal to grow the crystal.

In some embodiments, as shown in fig. 6, during growth of a crystal based on a seed crystal and a feedstock melt (pull growth stage), at least a portion of the through-hole 1411 of the sidewall of the barrel 141 may be located in the melt. The through hole 1411 may serve as a transfer passage for the melt inside the barrel 141 and the melt outside.

As described above, as the growth of the pulling process proceeds, a portion of the melt is consumed, the melt level gradually decreases, leading to a significant fluctuation in the temperature field near the level, and the inclusion of impurities in the crystal. Accordingly, in some embodiments, the sensing assembly may monitor and send crystal growth related information to the processing assembly. The processing assembly may control the pulling speed and/or rotational speed of the pulling assembly based on the crystal growth related information to control the rate and/or amount of immersion of the cartridge into the feedstock melt to maintain a constant level of the feedstock melt. For example, a level sensor may measure level position information and/or level height information of the melt within the growth chamber during crystal growth and send the level position information and/or level height information to the processing assembly. When the liquid level of the melt is lower than the initial liquid level of the melt due to partial melt consumption, the processing component can calculate the consumption speed and/or consumption amount of the melt based on the liquid level position information and/or the liquid level information, and further calculate the pulling speed of the pulling component based on the thickness of the barrel, the included angle between the side wall of the barrel and the horizontal plane and the like, so that the immersion speed of the barrel into the melt is equal to the consumption speed of the melt and/or the immersion amount of the barrel into the melt is equal to the consumption amount of the melt, the liquid level of the raw material melt is kept constant, the temperature field is kept stable, and the normal growth of crystals is ensured.

It should be noted that the above description of the process 900 is for illustration and description only, and is not intended to limit the scope of the application of the present disclosure. Various modifications and changes to flow 900 will be apparent to those skilled in the art in light of the present description. However, such modifications and variations are still within the scope of the present description.

Example 1

Raw materials silicon for SiC crystal growth and fluxing agent are placed in a growth cavity, and a crystal preparation device is assembled. The pulling assembly with the seed crystal is lowered to the vicinity of the raw material by the power assembly. The growth chamber is heated by the heating assembly to melt the feedstock to form a melt. In the heating and melting stage, the distance between the graphite paper at the bottom of the cylinder or the bottom of the cylinder and the melt liquid level is in the range of 5mm-10 mm. After the material melting is completed, the distance between the seed crystal seeding surface and the melt liquid level is within the range of 6mm-12 mm. The lifting assembly is lowered through the power assembly, and the seed crystal touches the graphite paper, so that the graphite paper falls into the melt. After a predetermined time (e.g., 0.5 h), the seed crystal is contacted with the melt and seeding is performed.

After the seed crystal is contacted with the melt for 10-30 min, the pulling assembly is rotated and moved upwards by the power assembly to grow the crystal. During upward movement of the pull assembly, the barrel will drop to be partially immersed and dissolved in the melt. During the pull-up growth phase, the sensing assembly monitors the crystal growth related information and sends the crystal growth related information to the processing assembly. The processing assembly controls the pulling speed and/or rotational speed of the pulling assembly based on the crystal growth related information to control the rate and/or amount of immersion of the cartridge into the feedstock melt to maintain a constant liquid level of the feedstock melt.

When the stop block on the connecting piece moves to the graphite rotating shaft, the stop block is blocked, the cylinder stops descending, and the lifting growth stage is finished at the moment. And the lifting assembly moves upwards through the power assembly to separate the crystal from the melt, so that the SiC crystal without inclusion is obtained.

Possible benefits of embodiments of the present description include, but are not limited to: (1) The crystal growth is carried out in the barrel of the guide assembly through the transmission movement of the lifting assembly and the guide assembly, the temperature of a temperature field is improved, the liquid level of the melt in the growth process is kept stable through the transmission movement, and the crystal quality is improved. (2) The diameter of the barrel is gradually increased along the direction from the bottom to the top of the barrel, volatilized silicon vapor can move upwards to the side wall of the barrel in the crystal growth process, and accordingly the volatilized silicon vapor is prevented from moving to the heat preservation component, so that the heat preservation performance and the service life of the heat preservation component are guaranteed. Further, in the pulling growth stage, as the pulling assembly is lifted, the barrel is lowered to be partially immersed in the melt, and silicon attached to the side wall of the barrel can perform silicon compensation on the melt, so that the segregation phenomenon of the components of the melt is reduced. Meanwhile, the cylinder can play a role of a heat reflecting screen, can reduce the supersaturation degree of the liquid level of the melt, and avoids spontaneous nucleation on the surface of the melt to form floating crystals. (3) During the pull-up growth phase, as the pull-up assembly is lifted up, a portion of the barrel may be immersed in the melt. The through holes of the side wall of the cylinder are immersed in the melt, and can serve as a transmission channel between the melt inside the cylinder and the melt outside the cylinder. The through holes can also prevent the floating crystals outside the barrel from entering the barrel, so that stable growth of the crystals is maintained. (4) The bottom of the cylinder is provided with graphite paper, and in the heating and material-melting stage, the graphite paper can prevent volatilized silicon vapor from adhering to the surface of the seed crystal, and further can ensure the crystal growth quality. In the seeding stage, the seed crystal may lightly touch the graphite paper to drop into and dissolve in the melt to provide the raw carbon required to produce silicon carbide crystals. (5) The processing assembly may control the pulling rate and/or rotational speed of the pulling assembly based on the crystal growth related information (e.g., level position information) to control the rate and/or amount of immersion of the cartridge into the feedstock melt to maintain a constant level of the feedstock melt, to maintain a steady temperature field, to ensure normal crystal growth, and to improve crystal quality. It should be noted that, the advantages that may be generated by different embodiments may be different, and in different embodiments, the advantages that may be generated may be any one or a combination of several of the above, or any other possible advantages that may be obtained.

While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing detailed disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements, and adaptations to the present disclosure may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within this specification, and therefore, such modifications, improvements, and modifications are intended to be included within the spirit and scope of the exemplary embodiments of the present invention.

Meanwhile, the specification uses specific words to describe the embodiments of the specification. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the present description. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the present description may be combined as suitable.

Likewise, it should be noted that in order to simplify the presentation disclosed in this specification and thereby aid in understanding one or more inventive embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof. This method of disclosure, however, is not intended to imply that more features than are presented in the claims are required for the present description. Indeed, less than all of the features of a single embodiment disclosed above.

In some embodiments, numbers describing the components, number of attributes are used, it being understood that such numbers being used in the description of embodiments are modified in some examples by the modifier "about," approximately, "or" substantially. Unless otherwise indicated, "about," "approximately," or "substantially" indicate that the number allows for a 20% variation. Accordingly, in some embodiments, numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and employ a method for preserving the general number of digits. Although the numerical ranges and parameters set forth herein are approximations that may be employed in some embodiments to confirm the breadth of the range, in particular embodiments, the setting of such numerical values is as precise as possible.

Each patent, patent application publication, and other material, such as articles, books, specifications, publications, documents, etc., referred to in this specification is incorporated herein by reference in its entirety. Except for application history documents that are inconsistent or conflicting with the content of this specification, documents that are currently or later attached to this specification in which the broadest scope of the claims to this specification is limited are also. It is noted that, if the description, definition, and/or use of a term in an attached material in this specification does not conform to or conflict with what is described in this specification, the description, definition, and/or use of the term in this specification controls.

Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments of this specification. Other variations are possible within the scope of this description. Thus, by way of example, and not limitation, alternative configurations of embodiments of the present specification may be considered as consistent with the teachings of the present specification. Accordingly, the embodiments of the present specification are not limited to only the embodiments explicitly described and depicted in the present specification.

Claims

1. A method of preparing a seed crystal, the method comprising:

placing the raw materials into a growth cavity;

lowering the seed-bonded pulling assembly to the vicinity of the feedstock, wherein,

the lifting assembly is in transmission connection with the guide assembly, the guide assembly comprises a cylinder, and the lifting assembly is at least partially positioned in the cylinder;

heating the growth chamber to form a feedstock melt; and

and growing a crystal based on the seed crystal and the raw material melt by the driving motion of the pulling assembly and the guiding assembly.

2. The crystal production method according to claim 1, wherein the diameter of the cylinder gradually increases in a direction from the bottom to the top of the cylinder.

3. The crystal production method according to claim 1, wherein a side wall of the cylinder is provided with a through hole.

4. A crystal production method according to claim 3, wherein,

the seed crystal is positioned below the through hole during the process of melting the raw material to form the raw material melt.

5. A crystal production method according to claim 3, wherein,

during the growth of a crystal based on the seed crystal and the feedstock melt, at least a portion of the through-hole is located in the feedstock melt.

6. A crystal production method according to claim 1, wherein,

during the process of melting the feedstock to form the feedstock melt, the distance between the bottom of the barrel and the melt level is within a first predetermined range.

7. A crystal production method according to claim 1, wherein,

and graphite paper is arranged at the bottom of the cylinder, and the distance between the graphite paper and the melt liquid level is within a first preset range in the process of melting the raw materials to form the raw material melt.

8. The crystal production method according to claim 7, wherein growing a crystal based on the seed crystal and the raw material melt by the driving motion of the pulling member and the guiding member comprises:

controlling the downward movement of the lifting assembly and the upward movement of the cylinder to enable the seed crystal to be close to the graphite paper and enable the graphite paper to fall into and be dissolved in the raw material melt.

9. The crystal production method according to claim 1, wherein growing a crystal based on the seed crystal and the raw material melt by the driving motion of the pulling member and the guiding member comprises:

by controlling the pull rate of the pull assembly, the rate and/or amount of immersion of the cartridge into the raw material melt is controlled to maintain a constant level of the raw material melt.

10. The crystal production method according to claim 1, wherein in growing a crystal based on the seed crystal and the raw material melt, the growth chamber is controlled to move so that the melt level is located at a high temperature line position.