Crystal growth method and apparatus

Abstract

The present disclosure discloses a crystal growth method and apparatus. The method includes placing a seed crystal and a target source material in a growth chamber of a crystal growth apparatus, growing a crystal using physical vapor transport (PVP) based on the seed crystal and the target source material, determining whether a predetermined condition is met during the crystal growth process, and, if so, replacing the sublimated target source material with a candidate source material. By replacing the sublimated target source material with the candidate source material, the present disclosure allows for the growth of large, high-quality crystals.

Description

Technical Field

[0001] The present application relates to the field of crystal growth, and particularly to a crystal growth method and apparatus for growing crystals with large dimensions and high quality.

Background Art

[0002] The Physical Vapor Transport (PVT) method is a commonly seen crystal growth method, which can sublime a material in a high-temperature region and grow crystals in a low-temperature region by utilizing the diffusion and transport of vapor. The PVT method can not only grow crystals by spontaneously forming crystal nuclei using crystal raw materials, but also deposit and grow crystals on existing seed crystals after sublimating the raw materials. However, in the conventional PVT method, the dimensions and quality of crystals are subject to certain limitations. Therefore, it is necessary to provide a crystal growth method and apparatus for growing crystals with large dimensions and high quality.

Summary of the Invention

[0003] One embodiment of the present application provides a crystal growth method, including placing a seed crystal and a target raw material substance in a growth chamber of a crystal growth apparatus, growing a crystal by the physical vapor transport method based on the seed crystal and the target raw material substance, determining whether a predetermined condition is satisfied during the crystal growth process, and replacing the sublimated target raw material substance with a candidate raw material substance when the predetermined condition is satisfied.

[0004] In some embodiments, the target raw material substance or the candidate raw material substance is a bulk material.

[0005] In some embodiments, the shape of the bulk material is a cube, a rectangular parallelepiped, or an irregular bulk.

[0006] In some embodiments, the thickness of the bulk material is smaller than a predetermined thickness threshold.

[0007] In some embodiments, the thickness of the bulk material is 30 to 40 mm.

[0008] In some embodiments, the target raw material substance and / or the candidate raw material substance are obtained through a treatment process, and the treatment process includes performing one or more types of treatments such as pressure molding, sintering, buffing, and purging on a powder raw material substance to obtain the target raw material substance and / or the candidate raw material substance.

[0009] In some embodiments, the treatment conditions for the sintering treatment are inert atmosphere conditions.

[0010] In some embodiments, replacing the sublimated target raw material substance with the candidate raw material substance includes placing the candidate raw material substance in the first region of the crystal growth apparatus, and controlling the candidate raw material substance by a control assembly so that the candidate raw material substance leaves the first region and enters the growth chamber, and the sublimated target raw material substance leaves the growth chamber and enters the second region of the crystal growth apparatus, thereby driving the sublimated target raw material substance.

[0011] In some embodiments, the temperature of the first region is lower than the temperature of the growth chamber, and the temperature difference between the first region and the growth chamber is smaller than a first predetermined temperature threshold.

[0012] In some embodiments, the method further includes pre-treating the candidate raw material substance in the first region, and the pre-treatment includes heating to the crystal sublimation temperature and maintaining the temperature for a predetermined time.

[0013] In some embodiments, the control assembly controls the speed at which the candidate raw material substance drives the sublimated target raw material substance to be smaller than a predetermined speed threshold.

[0014] In some embodiments, the control assembly controls the speed at which the candidate raw material substance drives the sublimated target raw material substance to be 100 to 150 mm / h.

[0015] In some embodiments, the temperature of the second region is lower than the temperature of the growth chamber, and the temperature difference between the second region and the growth chamber is smaller than a second predetermined temperature threshold.

[0016] In some embodiments, the crystal comprises silicon carbide, aluminum nitride, zinc oxide, or zinc telluride.

[0017] One embodiment of the present application provides a crystal growth apparatus, comprising a growth chamber for placing a seed crystal and a target raw material substance, and growing a crystal by physical vapor transport based on the seed crystal and the target raw material substance, and a control assembly for replacing the sublimated target raw material substance with a candidate raw material substance when predetermined conditions are satisfied during the crystal growth process.

[0018] In some embodiments, in order to replace the sublimated target raw material substance with the candidate raw material substance, the control assembly is for controlling the candidate raw material substance to drive the sublimated target raw material substance such that the candidate raw material substance enters the growth chamber away from the first region of the crystal growth apparatus, and the sublimated target raw material substance enters the second region of the crystal growth apparatus away from the growth chamber.

[0019] In some embodiments, the first region is for placing the candidate raw material substance and / or pre-treating the candidate raw material substance.

[0020] In some embodiments, the temperature of the first region is lower than the temperature of the growth chamber, and the temperature difference between the first region and the growth chamber is smaller than a first predetermined temperature threshold.

[0021] In some embodiments, the control assembly controls the speed at which the candidate raw material substance drives the sublimated target raw material substance to be lower than a predetermined speed threshold.

[0022] In some embodiments, the control assembly controls such that the speed at which the candidate raw material drives the sublimated target raw material is 100 to 150 mm / h.

[0023] In some embodiments, the temperature of the second region is lower than the temperature of the growth chamber, and the temperature difference between the second region and the growth chamber is smaller than a second predetermined temperature threshold.

Brief Description of the Drawings

[0024] The present application will be further described in terms of exemplary embodiments, which will be described in more detail with reference to the drawings. These embodiments are not restrictive, and in these embodiments, the same numbers indicate the same structures, and in these figures:

[0025]

Figure 1

[0026]

Figure 2

Modes for Carrying Out the Invention

[0027] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings necessary for describing the embodiments are briefly described below. Obviously, the drawings described below are merely some examples or embodiments of the present application, and those skilled in the art can apply the present application to other similar situations based on these drawings without creative effort. Unless otherwise apparent from the language environment or specifically stated, the same numbers in the figures represent the same structure or operation.

[0028] As will be understood, the terms "system", "apparatus", "unit" and / or "module" as used herein are a way of distinguishing different assemblies, elements, members, parts or assemblies at different levels. However, if other words can achieve the same purpose, the above words can be replaced with other expressions.

[0029] As shown in the present application and the claims, unless an exceptional situation is clearly presented in the context above and below, terms such as "a", "one", "a kind" and / or "the" do not particularly refer to the singular, but may include the plural. Generally, the terms "comprising" and "including" only present the steps and elements that have been clearly shown, but these steps and elements do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0030] The numerical ranges used herein are for simply and clearly expressing each numerical value included in the range.

[0031] In the present application, a flowchart is used to describe the operations performed by the system according to the embodiments of the present application. As will be understood, previous or subsequent operations are not necessarily executed exactly in order. On the contrary, each step may be processed in reverse order, or each step may be processed simultaneously. At the same time, other operations may be added to these processes, or operations may be performed to remove one or more steps from these processes.

[0032] The Physical Vapor Transport (PVT) method may be applied to multiple types of crystal growth. The conventional PVT method generally uses powder as the raw material. Taking the growth of a silicon carbide single crystal as an example, silicon carbide powder is generally used as the raw material. Along with the sublimation of the silicon carbide powder, the gas-phase components (e.g., Si, SiC2, Si2C) generated by its decomposition diffuse into the silicon carbide seed crystal driven by the axial temperature gradient, and a silicon carbide single crystal is grown and formed on the silicon carbide seed crystal. However, the solid component C generated by the sublimation decomposition of the silicon carbide powder deposits in the un-sublimed silicon carbide powder, gradually enriching carbon in the silicon carbide powder. For this reason, the sublimation rate of the silicon carbide powder decreases, making it impossible for the silicon carbide single crystal to continue growing rapidly, and ultimately limiting the growth length of the silicon carbide single crystal (e.g., limited to 30 - 50 mm). If the un-sublimed silicon carbide powder enriched with the above-mentioned carbon in the silicon carbide powder is continuously replaced, due to the light weight of the silicon carbide powder, during the replacement process, the silicon carbide powder will adhere to the silicon carbide seed crystal or the growing silicon carbide single crystal to form a coating. Therefore, the grown silicon carbide single crystal has defects, seriously affecting its crystal quality. Accordingly, one aspect of the present application provides a crystal growth method and apparatus, using a bulk as the raw material and dynamically monitoring the crystal growth process, and continuously replacing the raw material after sublimation with a candidate raw material according to the specific situation, so as to ensure that the crystal continues to grow rapidly, thereby preparing and obtaining a crystal with large dimensions and high quality. The embodiments of the present application may also be used to grow multiple types of crystals, such as silicon carbide, aluminum nitride, zinc oxide, or zinc telluride, etc.

[0033] FIG. 1 is a flowchart of an exemplary crystal growth method according to some embodiments of the present application. In some embodiments, process 100 may be automatically executed by a control system. For example, process 100 may be realized by control instructions, and the control system controls each assembly based on the control instructions to perform each operation of process 100. In some embodiments, process 100 may be executed semi-automatically. For example, one or more operations of process 100 may be manually executed by an operator. In some embodiments, when performing process 100, one or more additional operations not described herein may be added and / or one or more operations considered herein may be reduced. Also, the order of the operations shown in FIG. 1 is not restrictive.

[0034] In step 110, place the seed crystal and the target raw material in the growth chamber of the crystal growth apparatus.

[0035] The seed crystal may be a small crystal with the same crystal orientation as the crystal to be grown and may be used as the seed of the grown crystal. In some embodiments, the seed crystal may be manufactured based on the Physical Vapor Transport (PVT) method, Chemical Vapor Deposition (CVD) method, or Czochralski method.

[0036] The target raw material may include a material for supplying the seed crystal to grow into a crystal. For example, the components of the target raw material for silicon carbide crystals may include SiC. Further, for example, the components of the target raw material for aluminum nitride crystals may include AlN. In some embodiments, the target raw material may be a bulk material. The shape of the bulk material may be a cube, a rectangular parallelepiped, or an irregular bulk.

[0037] In some embodiments, in order to grow high-quality crystals and improve the utilization rate of the target raw material, the thickness of the bulk material may be smaller than a predetermined thickness threshold. The predetermined thickness threshold may be a system default value, or may be adjusted according to different situations. In some embodiments, the predetermined thickness threshold may be determined by the type of crystal to be grown, the dimensions of the crystal growth apparatus (for example, the growth chamber), etc. For example, the predetermined thickness threshold may be 41 mm, 43 mm, 45 mm, 47 mm, 49 mm, 51 mm, 53 mm, 55 mm, etc.

[0038] In some embodiments, the thickness of the bulk material may be 30 - 40 mm. In some embodiments, the thickness of the bulk material may be 31 - 39 mm. In some embodiments, the thickness of the bulk material may be 32 - 38 mm. In some embodiments, the thickness of the bulk material may be 33 - 37 mm. In some embodiments, the thickness of the bulk material may be 34 - 36 mm. In some embodiments, the thickness of the bulk material may be 35 mm. As an example, when growing silicon carbide crystals, the target raw material may be a silicon carbide bulk with a thickness of 30 - 40 mm.

[0039] In some embodiments, the target raw material substance may be obtained through a processing procedure. The processing procedure may include performing one or more of the following processes on the powdered raw material substance: compression molding, sintering, buffing, and purging. Specifically, the compression molding process may include placing the powdered raw material substance in a mold or other container and densifying the powdered raw material substance into a predetermined shape and / or dimension by the action of an external force (e.g., a predetermined pressure) (the product may be referred to as a "compression molding intermediate"). The sintering process may include achieving a predetermined strength and densifying the powdered raw material substance or the compression molding intermediate under predetermined conditions (e.g., a predetermined sintering temperature, a predetermined sintering time, and a sintering atmosphere) (the product may be referred to as a "sintering intermediate"). In some embodiments, to avoid oxidation of the powdered raw material substance, the sintering process may be performed in an inert atmosphere (e.g., nitrogen gas, helium gas). The buffing process may include smoothing the surface of an object to be buffed (e.g., the compression molding intermediate, the sintering intermediate) by reducing the surface roughness (the product may be referred to as a "buffing intermediate"). The purging process may include cleaning the surface of an object to be purged (e.g., the compression molding intermediate, the sintering intermediate, the buffing intermediate) under predetermined conditions (e.g., a predetermined purging pressure). In some embodiments, the purging process may be performed in an inert atmosphere (e.g., nitrogen gas, helium gas). In some embodiments, the processing procedure may further include performing a process such as uniform mixing on a plurality of types of powdered raw material substances.

[0040] In some embodiments, the purity of the powder raw material substance may be 99.999% or more. In some embodiments, the particle size of the powder raw material substance may be 20 - 50 μm. In some embodiments, the particle size of the powder raw material substance may be 22 - 48 μm. In some embodiments, the particle size of the powder raw material substance may be 24 - 46 μm. In some embodiments, the particle size of the powder raw material substance may be 26 - 44 μm. In some embodiments, the particle size of the powder raw material substance may be 28 - 42 μm. In some embodiments, the particle size of the powder raw material substance may be 30 - 40 μm. In some embodiments, the particle size of the powder raw material substance may be 32 - 38 μm. In some embodiments, the particle size of the powder raw material substance may be 34 - 36 μm. In some embodiments, the particle size of the powder raw material substance may be 35 μm.

[0041] In some embodiments, the components of the powder raw material substance and the target raw material substance may be the same as those of the crystal to be grown. For example, when growing aluminum nitride crystals, the components of the powder raw material substance and the target raw material substance may both be AlN. As an example, the powder raw material substance may be aluminum nitride powder with a purity greater than 99.999% and a particle size of 20 - 50 μm. The target raw material substance may be an aluminum nitride bulk produced after pressure molding, sintering, buffing, and purging the above-mentioned aluminum nitride powder.

[0042] In some embodiments, the components of the powder raw material substance and the target raw material substance may be different from those of the crystal to be grown. For example, when growing 6H-SiC crystals, the components of the powder raw material substance and the target raw material substance may include SiC and Si. As an example, the powder raw material substance may include a predetermined ratio of silicon carbide powder with a purity greater than 99.999% and a particle size of 20 to 50 μm, and silicon powder with a purity greater than 99.999% and a particle size of 20 to 40 μm. The target raw material substance may be a bulk material manufactured after mixing, pressure molding, sintering, buffing, and purging the above silicon carbide powder and silicon powder. The silicon powder can not only improve the adhesiveness of the powder raw material substance and can be easily pressure molded and sintered into the target raw material substance, but also enrich silicon in the growth chamber of the crystal growth apparatus and contribute to the growth of 6H-SiC crystals. However, since the melting point of silicon is low, if the content of the silicon powder is too high, the silicon powder will contaminate the growth chamber. Therefore, the content of the silicon powder should be appropriate. In some embodiments, the predetermined ratio may be that the mass ratio of the silicon powder to the silicon carbide powder is 5% to 10%. In some embodiments, the predetermined ratio may be that the mass ratio of the silicon powder to the silicon carbide powder is 6% to 9%. In some embodiments, the predetermined ratio may be that the mass ratio of the silicon powder to the silicon carbide powder is 6.5% to 8.5%. In some embodiments, the predetermined ratio may be that the mass ratio of the silicon powder to the silicon carbide powder is 7% to 8%. In some embodiments, the predetermined ratio may be that the mass ratio of the silicon powder to the silicon carbide powder is 7.5%.

[0043] In some embodiments, the interior of the growth chamber (e.g., crucible) may have a predetermined temperature gradient (e.g., a predetermined axial temperature gradient) to promote crystal growth. The predetermined temperature gradient may be determined by the type of crystal to be grown and the like. In some embodiments, the seed crystal may be placed in a lower temperature region and the target raw material may be placed in a higher temperature region. In some embodiments, the seed crystal and the target raw material may be coaxially placed and maintain a predetermined axial distance. In some embodiments, the seed crystal may be placed in the top region inside the growth chamber. For example, the seed crystal may be adhesively fixed to the top cover inside the growth chamber with an adhesive (e.g., sucrose). As an example, first, sucrose may be evenly spread on the top cover inside the growth chamber, and then it may be heated and kept warm for a predetermined time. Next, the seed crystal may be placed on the top cover where sucrose is evenly spread, and the seed crystal may be made concentric with the top cover. Further, after pressing the seed crystal, the seed crystal may be heated together with the top cover where sucrose is evenly spread and kept warm for a predetermined time. After it cools slowly, the seed crystal is fixed to the top cover inside the growth chamber. In some embodiments, the target raw material may be evenly placed in the bottom region of the growth chamber and the target raw material may be heated by a heating assembly. More descriptions about the placement regions of the seed crystal and the target raw material in the growth chamber may refer to other positions of this application, such as FIG. 2 and its description.

[0044] Step 120: Grow a crystal by physical vapor transport method based on the seed crystal and the target raw material.

[0045] As described in Step 110, the target raw material is located in a higher temperature region and the seed crystal is located in a lower temperature region. In the process of growing a crystal by physical vapor transport method (PVT, Physical Vapor Transport), the target raw material sublimes and decomposes into vapor-phase components (taking the case of growing a silicon carbide crystal as an example, the vapor-phase components include Si, SiC2, Si2C, etc.). The vapor-phase components diffuse to the seed crystal driven by the axial temperature gradient in the growth chamber and gradually grow along the seed crystal.

[0046] Step 130: Determine whether the predetermined conditions are satisfied during the crystal growth process.

[0047] In some embodiments, the predetermined conditions may include that the crystal growth time reaches a predetermined time, the crystal growth rate reaches a first predetermined growth rate, the sublimation rate of the target raw material reaches a predetermined sublimation rate, etc. In some embodiments, the predetermined time, the first predetermined growth rate, and / or the predetermined sublimation rate may be system default values and may be adjusted according to different situations. For example, the predetermined time, the first predetermined growth rate, and / or the predetermined sublimation rate may be determined by the type of the grown crystal, the components of the target raw material, the dimensions of the target raw material, etc. As an example, in order to ensure that the target raw material is fully utilized and the quality of the crystal is relatively high, the predetermined time should be within a predetermined time interval. As an example, when growing 6H-SiC crystals, the mass ratio of silicon powder to silicon carbide powder in the target raw material is 8%, and the thickness of the target raw material is 36 mm. In such a case, the predetermined time may be 20 to 25 hours.

[0048] In some embodiments, the growth rate of the crystal may be calculated by formula (1). JPEG0007704775000001.jpg11170Here, v represents the growth rate of the crystal, Δm represents the weight increase of the growing crystal within a specific time, ρ represents the density of the crystal, t represents time, and S represents the inner diameter area of the top cover of the growth chamber. In some embodiments, the weight increase of the crystal within a specific time may be measured by a weight sensor. The density of the crystal is its physical property. For example, the density of silicon carbide crystal is 3.21 g / cm 3 ³. During the crystal growth process, the increase in the weight of the crystal is mainly reflected in terms of length, and since the increase in diameter is small, the increase in the diameter of the crystal may be ignored.

[0049] When it is determined that the specified conditions are satisfied, the process may enter step 140, and the sublimated target raw material substance may be replaced with a candidate raw material substance. When it is determined that the specified conditions are not satisfied, step 120 may be continuously performed, that is, a crystal may be grown by physical vapor transport method based on the seed crystal and the target raw material substance.

[0050] In step 140, the sublimated target raw material substance is replaced with a candidate raw material substance.

[0051] The sublimated target raw material substance may refer to the target raw material substance after sublimation decomposition. In some embodiments, the components of the sublimated target raw material substance may be the same as those of the target raw material substance. For example, when growing aluminum nitride crystals, the components of the target raw material substance may be AlN. Since only the gas phase components AlN, Al, and N2 are generated by the sublimation decomposition of aluminum nitride as the target raw material substance, the components of the sublimated target raw material substance are also AlN. In some embodiments, the components of the sublimated target raw material substance may be different from those of the target raw material substance. For example, when growing 6H-SiC crystals, the components of the target raw material substance may be SiC and Si. The sublimation decomposition of silicon nitride as the target raw material substance generates gas phase components (e.g., Si, SiC2, Si2C) and a solid phase component C, and since the solid phase component C adheres to the sublimated target raw material substance, the components of the sublimated target raw material substance include SiC, C, and / or Si.

[0052] In some embodiments, as described in step 110, the candidate raw material substance may be obtained through a processing procedure. The processing procedure may include performing one or more of the processes of pressure molding, sintering, buff polishing, and purging on the powdered raw material substance. In some embodiments, the processing procedures for the candidate raw material substance and the target raw material substance may be the same or different. In some embodiments, the candidate raw material substance and the target raw material substance may be the same or different. For example, the components of the candidate raw material substance may be the same as those of the target raw material substance, and the dimensions of the candidate raw material substance may be the same as those of the target raw material substance. Further, for example, the components of the candidate raw material substance may be the same as those of the target raw material substance, but the dimensions of the candidate raw material substance may be different from those of the target raw material substance. Further, for example, the components of the candidate raw material substance may be different from those of the target raw material substance, but the dimensions of the candidate raw material substance may be the same as those of the target raw material substance. Further, for example, the components of the candidate raw material substance may be different from those of the target raw material substance, and the dimensions of the candidate raw material substance may be different from those of the target raw material substance.

[0053] In some embodiments, the candidate raw material substance may be placed in the first region of the crystal growth apparatus, and the first region is adjacent to the growth chamber (for example, located on one side of the growth chamber). In some embodiments, the control assembly may control the candidate raw material substance so that the candidate raw material substance moves away from the first region and into the growth chamber, and the sublimated target raw material substance moves away from the growth chamber and into the second region of the crystal growth apparatus, and the second region is adjacent to the growth chamber (for example, located on the other side of the growth chamber).

[0054] In some embodiments, the first region may be for pre-treating the candidate raw material substance. The pre-treatment may include heating the candidate raw material substance to its sublimation temperature and holding it for a predetermined time so that the sublimation rate of the candidate raw material substance when it enters the growth chamber corresponds to the sublimation rate of the target raw material substance (i.e., the sublimated target raw material substance) in the growth chamber at that time, thereby ensuring crystal growth. The predetermined time may be a system default value or may be adjusted according to different situations. For example, the predetermined time may be determined by the type, dimensions, etc. of the candidate raw material substance. In some embodiments, the temperature of the first region may be lower than the temperature of the growth chamber, and the temperature difference between the first region and the growth chamber may be smaller than a first predetermined temperature threshold. The first predetermined temperature threshold may be a system default value or may be adjusted according to different situations. For example, the first predetermined temperature threshold may be determined by the distance between the first region and the growth chamber, the type of the grown crystal, etc.

[0055] In some embodiments, the second region may be for temporarily storing the sublimated target raw material substance that has been replaced. In some embodiments, to ensure crystal growth and crystal quality by maintaining the temperature of the growth chamber stable, the temperature of the second region may be lower than the temperature of the growth chamber, and the temperature difference between the second region and the growth chamber may be smaller than a second predetermined temperature threshold. Similarly, the second predetermined temperature threshold may be a system default value or may be adjusted according to different situations. For example, the second predetermined temperature threshold may be determined by the distance between the second region and the growth chamber, the type of the grown crystal, etc.

[0056] In some embodiments, the control assembly controls such that the speed at which the candidate raw material substance drives the sublimated target raw material substance is less than a predetermined speed threshold. In some embodiments, the predetermined speed threshold may be a system default value and may be adjusted according to different situations. For example, the predetermined speed threshold may be determined by the weight of the target raw material substance, the sublimated target raw material substance and the candidate raw material substance, the type of the grown crystal, etc. By way of example, the predetermined speed threshold may be 160 mm / h, 180 mm / h, 200 mm / h, 220 mm / h, 240 mm / h, etc.

[0057] In some embodiments, the control assembly controls such that the speed at which the candidate raw material substance drives the sublimated target raw material substance may be set to 100-150 mm / h. In some embodiments, the control assembly controls such that the speed at which the candidate raw material substance drives the sublimated target raw material substance may be set to 105-145 mm / h. In some embodiments, the control assembly controls such that the speed at which the candidate raw material substance drives the sublimated target raw material substance may be set to 110-140 mm / h. In some embodiments, the control assembly controls such that the speed at which the candidate raw material substance drives the sublimated target raw material substance may be set to 115-135 mm / h. In some embodiments, the control assembly controls such that the speed at which the candidate raw material substance drives the sublimated target raw material substance may be set to 120-130 mm / h. In some embodiments, the control assembly controls such that the speed at which the candidate raw material substance drives the sublimated target raw material substance may be set to 122-128 mm / h. In some embodiments, the control assembly controls such that the speed at which the candidate raw material substance drives the sublimated target raw material substance may be set to 124-126 mm / h. The above speeds are only for reference, and the present application does not limit the speed and the predetermined speed threshold, and it is only necessary to ensure that the crystal growth process is not interfered with or affected during the process in which the candidate raw material substance enters the growth chamber and the sublimated target raw material substance leaves the growth chamber.

[0058] In some embodiments, as described in step 130, the increase in the weight of the crystal is mainly reflected in terms of length. As the crystal grows, the distance between the location where the crystal length increases (i.e., the location where the crystal is growing) and the target raw material and / or candidate raw material is shortened. Therefore, the growth temperatures in the length direction of the crystal do not match, which affects the performance of the crystal (e.g., uniformity), and further affects the quality of the crystal. In order to grow large-sized and uniform crystals, it may be determined whether certain predetermined conditions are satisfied during the crystal growth process. In some embodiments, the predetermined conditions may include that the distance between the location where the crystal length increases and the target raw material and / or candidate raw material reaches a predetermined distance, and that the growth rate of the crystal reaches a second predetermined growth rate, etc. In some embodiments, the predetermined distance and the second predetermined growth rate may be system default values, or may be adjusted according to different situations. For example, the predetermined distance and the second predetermined growth rate may be determined by the type of the growing crystal, the inner diameter area of the top cover of the growth chamber, etc. As an example, in order to grow large-sized and uniform crystals, the second predetermined growth rate should be within a predetermined growth rate range. As an example, when growing 6H-SiC crystals, the second predetermined growth rate may be 0.7 mm / h to 0.8 mm / h. In some embodiments, the second predetermined growth rate may be 0.8 mm / h. In some embodiments, the second predetermined growth rate may be 0.78 mm / h. In some embodiments, the second predetermined growth rate may be 0.76 mm / h. In some embodiments, the second predetermined growth rate may be 0.74 mm / h. In some embodiments, the second predetermined growth rate may be 0.72 mm / h. In some embodiments, the second predetermined growth rate may be 0.7 mm / h.

[0059] When determining that the specified conditions are satisfied, the crystal growing at a specific speed may be lifted up. In some embodiments, in order to grow large-sized and uniform crystals, the specific speed may be equal to the growth speed of the crystal during growth, and the lifting direction may be the opposite direction in which the crystal grows in the axial direction. When determining that the specified conditions are not satisfied, the crystal may continue to be grown by physical vapor transport based on the seed crystal and the target raw material.

[0060] However, the descriptions related to the above-described process 100 are merely exemplary and for illustrative purposes, and do not limit the scope of application of the present application. A person skilled in the art can make various modifications and changes to process 100 based on the guidance of the present application. However, these modifications and changes are still included within the scope of the present application.

[0061] FIG. 2 is a schematic cross-sectional structure diagram of an exemplary crystal growth apparatus according to some embodiments of the present application.

[0062] As shown in FIG. 2, the crystal growth apparatus 200 may include a growth chamber 210 and a control assembly (not shown).

[0063] The growth chamber 210 may be for placing the seed crystal 250 and the target raw material substance 240, and crystals can be grown by physical vapor transport based on the seed crystal 250 and the target raw material substance 240. In some embodiments, the shape of the growth chamber 210 may be a cylinder, a cuboid, a cube, an arc-shaped chamber, etc. In some embodiments, the growth chamber 210 may include a top cover 212, side walls (e.g., a first side wall 214, a second side wall 216), and a bottom cover 218. In some embodiments, the top cover 212, the side walls, and the bottom cover 218 may be manufactured (e.g., sintered) from graphite with a purity greater than 99.99%. In some embodiments, a material (e.g., tantalum carbide) that prevents oxidation and can withstand high temperatures may be coated on the surface of the graphite. In some embodiments, a heating element 220 may be disposed around the side walls. The heating element 220 may be for heating the growth chamber 210 to maintain an axial temperature gradient necessary for crystal growth in the growth chamber 210. In some embodiments, the heating element 220 may be an induction coil.

[0064] In some embodiments, the seed crystal 250 may be adhesively fixed inside the top cover 212. In some embodiments, the growth chamber 210 may include a first portion (i.e., the upper portion) surrounded by the top cover 212 and the first sidewall 214, and a second portion (i.e., the lower portion) surrounded by the bottom cover 218 and the second sidewall 216. In some embodiments, the top cover 212 and the first sidewall 214 may be separable, thereby making the top cover 212 removable to place the seed crystal, and enabling the top cover 212 and the growing crystal to be lifted up as a whole to obtain large-sized and uniform crystals. The bottom cover 218 and the second sidewall 216 may be separable or integrally formed. In some embodiments, a heat conduction element 230 may be placed inside the second portion. The target raw material 240 may be placed on the heat conduction element 230. The heat conduction element 230 can transfer the heat generated by the heating element 220 to the target raw material 240. In some embodiments, the heat conduction element 230 may be manufactured (e.g., sintered) from graphite with a purity greater than 99.99%. In some embodiments, a material that prevents oxidation and can withstand high temperatures (e.g., tantalum carbide) may be coated on the surface of the graphite.

[0065] In some embodiments, the first sidewall 214 and the second sidewall 216 may be separated by a predetermined distance so that the candidate raw material substance 280 can enter the growth chamber 210 and the target raw material substance 240 after sublimation (for the sake of explanation, the target raw material substance and the target raw material substance after sublimation are both denoted as 240) can leave the growth chamber 210. In some embodiments, the predetermined distance may be a system default value and may be adjusted according to different situations. In some embodiments, in order to ensure that the candidate raw material substance 280 can smoothly enter the growth chamber 210 and the target raw material substance 240 after sublimation can smoothly leave the growth chamber 210, the predetermined distance should be greater than the thicknesses of the candidate raw material substance 280 and the target raw material substance 240 after sublimation. In some embodiments, in order to ensure that the temperature in the growth chamber 210 is uniform, it is also necessary to make the predetermined distance greater than the thicknesses of the candidate raw material substance 280 and the target raw material substance 240 after sublimation and smaller than a predetermined value.

[0066] In some embodiments, the control assembly may be for controlling the candidate raw material substance 280 to drive the target raw material substance 240 after sublimation so that the candidate raw material substance 280 leaves the first region 260 and enters the growth chamber 210, and the target raw material substance 240 after sublimation leaves the growth chamber 210 and enters the second region 270.

[0067] In some embodiments, the first region 260 may be for placing the candidate raw material substance 280 and / or pre-treating the candidate raw material substance 280. In some embodiments, the pre-treatment may include heating the candidate raw material substance 280 to its sublimation temperature and keeping it at that temperature for a predetermined time so that the sublimation rate of the candidate raw material substance 280 when it enters the growth chamber 210 corresponds to the sublimation rate of the target raw material substance (i.e., the target raw material substance after sublimation) 240 in the growth chamber 210 at that time, thereby ensuring the growth of crystals.

[0068] In some embodiments, the first region 260 may include a first upper cover 262 and a first lower cover 264. The first upper cover 262 and the first lower cover 264 may be made of graphite with a purity greater than 99.99% (for example, manufactured by sintering). In some embodiments, a material that prevents oxidation and can withstand high temperatures (for example, tantalum carbide) may be coated on the surface of the graphite. In some embodiments, the first upper cover 262 and the first lower cover 264 may be surrounded by a first heating element 266 for pre-treating the candidate raw material substance 280 placed in the first region 260. In some embodiments, the first heating element 266 may be a graphite resistance heating element. In some embodiments, the temperature of the first region 260 may be lower than the temperature of the growth chamber 210, and the temperature difference between the first region 260 and the growth chamber 210 may be smaller than a first predetermined temperature threshold.

[0069] In some embodiments, the second region 270 may be for temporarily storing the sublimated target raw material substance 240 after substitution. In some embodiments, the second region 270 may include a second upper cover 272 and a second lower cover 274. The second upper cover 272 and the second lower cover 274 may be made of graphite with a purity greater than 99.99% (for example, manufactured by sintering). In some embodiments, a material that prevents oxidation and can withstand high temperatures (for example, tantalum carbide) may be coated on the surface of the graphite. In some embodiments, the second upper cover 272 and the second lower cover 274 may be surrounded by a second heating element 276 for ensuring crystal growth and crystal quality by maintaining the temperature of the growth chamber 210 stable. In some embodiments, the second heating element 276 may be a graphite resistance heating element. In some embodiments, the temperature of the second region 270 may be lower than the temperature of the growth chamber 210, and the temperature difference between the second region 270 and the growth chamber 210 may be smaller than a second predetermined temperature threshold.

[0070] In some embodiments, the control assembly may include a sensor (not shown), a controller (not shown), and a drive member 290. The sensor may be for detecting relevant parameters in the crystal growth process, such as crystal growth time, crystal growth rate, sublimation rate of the target raw material, etc. For example, the sensor may detect time, the weight by which the crystal has increased within that time, etc., and based on the density of the crystal manually input or pre-stored, the inner diameter area of the top cover, the detected time, and the weight by which the crystal has increased within that time, calculate the crystal growth rate according to formula (1). In some embodiments, the sensor may include a timer, a temperature sensor, a weight sensor, etc. The controller may be for determining whether to meet a predetermined condition based on relevant parameters in the crystal growth process. For example, determining whether the crystal growth time reaches a predetermined time, determining whether the crystal growth rate reaches a first predetermined growth rate, determining whether the sublimation rate of the target raw material reaches a predetermined sublimation rate, etc. When the predetermined condition is met, the controller may control the drive member 290 to drive the candidate raw material 280 so that the candidate raw material 280 can drive the target raw material 240 after sublimation. Thereby, the candidate raw material 280 can leave the first region 260 and enter the growth chamber 210, and the target raw material 240 after sublimation can leave the growth chamber 210 and enter the second region 270, realizing the replacement of the target raw material 240 after sublimation with the candidate raw material 280. In some embodiments, the controller may include a microprocessor, a central processing unit (CPU), a physics processing unit (PPU), a memory control unit (MCU), a reduced instruction set computer (RISC), etc. In some embodiments, the drive member 290 may include a drive rod, a manipulator, etc.

[0071] In some embodiments, as described in step 140, the control assembly may control such that the rate at which the target raw material 240 is driven by the sublimated candidate raw material 280 is less than a predetermined rate threshold. In some embodiments, the predetermined rate threshold may be a system default value and may be adjusted according to different situations. For example, the predetermined rate threshold may be determined by the weight of the target raw material, the sublimated target raw material and the candidate raw material, the type of the grown crystal, etc. For more descriptions on the control assembly controlling the rate at which the target raw material 240 is driven by the sublimated candidate raw material 280, reference may be made to other positions of this application, such as FIG. 1 and its description.

[0072] In some embodiments, further, the controller may further be for determining whether a predetermined condition is satisfied based on relevant parameters in the crystal growth process. For example, it may be determined whether the distance between the location where the crystal length has increased and the target raw material and / or the candidate raw material reaches a predetermined distance, and it may be determined whether the crystal growth rate reaches a second predetermined growth rate. When the predetermined condition is satisfied, the controller can control a lift-up member (not shown) (for example, a lift-up rod, a manipulator) to lift up the growing crystal at a specific speed. In some embodiments, in order to grow and obtain a large-size and uniform crystal, the specific speed may be equal to the growth rate of the growing crystal, and the lift-up direction may be the reverse direction in which the crystal grows axially. For more descriptions on the crystal growth rate and the second predetermined growth rate, reference may be made to other positions of this application, such as FIG. 1 and its description.

[0073] However, the above description is merely illustrative and for the purpose of explanation, and does not limit the scope of application of this application. A person skilled in the art can make various modifications and changes based on the guidance of this application. However, these modifications and changes are still included within the scope of this application. For example, the sensor may send the detected time, the weight by which the crystal has increased within this time, etc. to the controller, and the controller may calculate the growth rate of the crystal.

[0074] Example 1

[0075] The powder raw material substances are silicon carbide powder with a purity greater than 99.999% and a particle size of 48 μm and silicon powder with a purity of 99.999% and a particle size of 41 μm, and the mass ratio of the silicon powder to the silicon carbide powder is 10%. Using a mixer, stir for 8 hours to uniformly mix the silicon carbide powder and the silicon powder. Next, put the uniformly mixed powder raw material substances into a mold and spread them flat in the mold. Then, cover the upper cover plate of the mold, and place a steel plate with the same dimensions as the mold on the upper cover plate of the mold. Use a pressure of 20 Mpa to consolidate the powder raw material substances. Further, take out the upper cover plate of the mold, put the mold containing the powder raw material substances into a vacuum high-temperature furnace for sintering. Set the sintering atmosphere as an argon gas atmosphere, the sintering pressure as 7×10 4 Pa, and the sintering temperature as 1850 °C. After sintering for 20 hours and the mold cools to room temperature, release the mold and take it out to obtain a porous silicon carbide ceramic plate. Further, perform buff polishing treatment on the surface of the porous silicon carbide ceramic plate to smooth its surface, and purge the surface of the porous silicon carbide ceramic plate with nitrogen gas with a purity greater than 99.99% at 0.02 Mpa. The thickness of the manufactured porous silicon carbide ceramics is 33 mm.

[0076] A 6H-SiC seed crystal with a diameter of 150 mm is prepared using the PVT method and adhesively fixed to the top cover of the growth chamber (for example, the lid of a graphite crucible). Specifically, first, sucrose, which is an adhesive, is evenly spread on the inside of the lid of the graphite crucible, then it is placed in a muffle furnace, heated to 150 °C, held for 5 h, then the temperature is raised to 200 °C and held for 7 h. Further, the 6H-SiC seed crystal is placed inside the lid of the graphite crucible where sucrose is evenly spread, ensuring that the 6H-SiC seed crystal is concentric with the lid of the graphite crucible. Next, a single silicon carbide wafer that is clean and the same size as the 6H-SiC seed crystal is placed on the 6H-SiC seed crystal, and then a stainless steel block with a diameter of 150 mm and a thickness of 20 mm is pressed on the single silicon carbide wafer. Next, the whole is placed in a muffle furnace, heated to 380 °C, held for 5 h, and taken out after it slowly cools to room temperature.

[0077] A single porous silicon carbide ceramic is placed in the growth chamber. The growth surface direction of the 6H-SiC seed crystal is deflected 4° from

[0001] and directed to

[0110] . The vertical distance between the seed crystal and the porous silicon carbide ceramic plate is adjusted to 30 mm.

[0078] Heat the growth chamber to raise its temperature to 2320 °C, and the temperature of the lid of the graphite crucible rises to 2245 °C. Place two pieces of porous silicon carbide ceramics (precursor raw materials) in the first region and raise the temperature to 1700 °C, and heat the second region to a temperature of 1700 °C. The growth atmosphere is argon gas, and the pressure in the crystal growth process of the growth chamber, the first region and the second region is maintained at 15 Torr. After the porous silicon carbide ceramics have sublimated and decomposed for 20 hours, replacement is carried out. Before replacement, first heat the first region to the same temperature as the growth chamber (i.e., 2320 °C) and keep it warm for 1 hour. When carrying out the replacement, control the driving member to slowly push one piece of porous silicon carbide ceramics (precursor raw material) in the first region forward into the growth chamber, and set the pushing speed to 100 mm / h. After completely pushing the porous silicon carbide ceramics to be replaced into the growth chamber, sublime and decompose it for 20 hours and then carry out the replacement once again. The sublimated porous silicon carbide ceramics after replacement are pushed into the second region and temporarily stored.

[0079] After the silicon carbide ceramics after sublimation have been replaced twice, the diameter of the growth surface of the grown 6H-SiC ingot is 158 mm, and the growth length reaches 53 mm.

[0080] Example 2

[0081] The powder raw material is silicon carbide powder with a purity greater than 99.999% and a particle size of 48 μm and silicon powder with a purity of 99.999% and a particle size of 41 μm, and the mass ratio of silicon powder to silicon carbide powder is 10%. Use a mixer to stir for 8 hours to uniformly mix the silicon carbide powder and the silicon powder. Next, put the uniformly mixed powder raw material into a mold and spread it flat in the mold. Then, cover the upper cover plate of the mold and place a steel plate with the same dimensions as the mold on the upper cover plate of the mold. Use a pressure of 15 Mpa to compact the powder raw material. Further, take out the upper cover plate of the mold, put the mold containing the powder raw material into a vacuum high-temperature furnace for sintering, set the sintering atmosphere to an argon gas atmosphere, and the sintering pressure to 7×10 4Let \(P_a\) be the pressure and the sintering temperature be \(1800^{\circ}C\). After sintering for 20 hours and then cooling the mold to room temperature, it is demolded and taken out to obtain a porous silicon carbide ceramic plate. Further, buff polishing treatment is performed on the surface of the porous silicon carbide ceramic plate to smooth its surface, and the surface of the porous silicon carbide ceramic plate is purged with nitrogen gas having a purity greater than \(99.99\%\) at \(0.02\) Mpa. The thickness of the manufactured porous silicon carbide ceramics is \(35\) mm.

[0082] A 6H-SiC seed crystal with a diameter of \(150\) mm is prepared using the PVT method and is adhesively fixed to the top cover of the growth chamber (for example, the lid of a graphite crucible). Specifically, first, sucrose, which is an adhesive, is evenly spread on the inside of the lid of the graphite crucible, then it is placed in a muffle furnace, heated to \(150^{\circ}C\), held for \(5\) h, then the temperature is raised to \(200^{\circ}C\) and held for \(7\) h. Further, the 6H-SiC seed crystal is placed inside the lid of the graphite crucible where sucrose is evenly spread, ensuring that the 6H-SiC seed crystal is concentric with the lid of the graphite crucible. Next, a single silicon carbide wafer that is clean and has the same size as the 6H-SiC seed crystal is placed on the 6H-SiC seed crystal, and then a stainless steel block with a diameter of \(150\) mm and a thickness of \(20\) mm is pressed on the single silicon carbide wafer. Next, the whole is placed in a muffle furnace, heated to \(380^{\circ}C\), held for \(5\) h, and taken out after it cools slowly to room temperature.

[0083] A single porous silicon carbide ceramic is placed in the growth chamber. The growth surface direction of the 6H-SiC seed crystal is deflected \(4^{\circ}\) from \(

[0001] \) and directed to \(

[0110] \). The vertical distance between the seed crystal and the porous silicon carbide ceramic plate is adjusted to \(30\) mm.

[0084] Heat the growth chamber to raise its temperature to 2300 °C, and the temperature of the lid of the graphite crucible rises to 2218 °C. Place four pieces of porous silicon carbide ceramics (precursor raw material) in the first region and raise the temperature to 1700 °C, and heat the second region to make its temperature 1700 °C. The growth atmosphere is argon gas, and the pressure in the crystal growth process of the growth chamber, the first region and the second region is maintained at 15 Torr. After the porous silicon carbide ceramics have sublimated and decomposed for 20 hours, replacement is carried out. Before replacement, first heat the first region to the same temperature as the growth chamber (i.e., 2300 °C) and keep it warm for 1 hour. When carrying out replacement, control the driving member to slowly push one piece of porous silicon carbide ceramics (precursor raw material) in the first region forward into the growth chamber, and set the pushing speed to 130 mm / h. After completely pushing the porous silicon carbide ceramics to be replaced into the growth chamber, let it sublimate and decompose for 20 hours and then carry out replacement. The replaced sublimated porous silicon carbide ceramics are pushed into the second region and temporarily stored.

[0085] After replacing the sublimated silicon carbide ceramics four times, the diameter of the growth surface of the grown 6H-SiC ingot is 163 mm, and the growth length reaches 77 mm.

[0086] Example 3

[0087] The powder raw material is silicon carbide powder with a purity greater than 99.999% and a particle size of 48 μm and silicon powder with a purity of 99.999% and a particle size of 41 μm, and the mass ratio of silicon powder to silicon carbide powder is 5%. Use a mixer to stir for 8 hours to uniformly mix the silicon carbide powder and the silicon powder. Next, put the uniformly mixed powder raw material into a mold and spread it flat in the mold. Then, cover the upper cover plate of the mold and place a steel plate with the same dimensions as the mold on the upper cover plate of the mold. Use a pressure of 20 Mpa to compact the powder raw material. Further, take out the upper cover plate of the mold, and put the mold containing the powder raw material into a vacuum high-temperature furnace for sintering. The sintering atmosphere is an argon gas atmosphere, and the sintering pressure is 7×10 4Take Pa and set the sintering temperature to 1850 °C. After sintering for 20 hours, when the mold cools to room temperature, it is demolded and taken out to obtain a porous silicon carbide ceramic plate. Further, buff polishing treatment is performed on the surface of the porous silicon carbide ceramic plate to smooth its surface, and the surface of the porous silicon carbide ceramic plate is purged with nitrogen gas having a purity greater than 99.99% at 0.02 Mpa. The thickness of the manufactured porous silicon carbide ceramics is 35 mm.

[0088] Prepare a 4H-SiC seed crystal with a diameter of 150 mm using the PVT method and adhesively fix it to the top cover of the growth chamber (for example, the lid of a graphite crucible). Specifically, first, spread sucrose, which is an adhesive, evenly on the inside of the lid of the graphite crucible, then put it into a muffle furnace, heat it to 150 °C and keep it warm for 5 h, then raise the temperature to 200 °C and keep it warm for 7 h. Further, put the 4H-SiC seed crystal into the inside of the lid of the graphite crucible where sucrose is evenly spread, ensure that the 4H-SiC seed crystal is concentric with the lid of the graphite crucible, then place a single silicon carbide wafer that is clean and the same size as the 4H-SiC seed crystal on the 4H-SiC seed crystal, and further press a stainless steel block with a diameter of 150 mm and a thickness of 20 mm on the single silicon carbide wafer. Next, put it into a muffle furnace as a whole, heat it to 380 °C and keep it warm for 5 h, and take it out after it cools slowly to room temperature.

[0089] Place a single porous silicon carbide ceramic in the growth chamber. The growth surface direction of the 4H-SiC seed crystal is a direction that is deflected 4° from

[0000] and directed to

[0110] . Adjust the vertical distance between the seed crystal and the porous silicon carbide ceramic plate to 30 mm.

[0090] The growth chamber is heated to raise its temperature to 2200 °C, and the temperature of the lid of the graphite crucible rises to 2117 °C. Two pieces of porous silicon carbide ceramics (precursor raw materials) are placed in the first region and the temperature is raised to 1700 °C, and the second region is heated to a temperature of 1700 °C. The growth atmosphere is argon gas, and the pressure in the crystal growth process of the growth chamber, the first region and the second region is maintained at 15 Torr. After the porous silicon carbide ceramics have sublimated and decomposed for 20 hours, replacement is carried out. Before replacement, first the first region is heated to the same temperature as the growth chamber (i.e., 2200 °C) and held for 1 hour. When carrying out the replacement, the driving member is controlled to slowly push one piece of porous silicon carbide ceramics (precursor raw material) in the first region forward into the growth chamber, and the pushing speed is 100 mm / h. After the porous silicon carbide ceramics to be replaced are completely pushed into the growth chamber, it is sublimated and decomposed for 20 hours and then replacement is carried out. The replaced sublimated porous silicon carbide ceramics are pushed into the second region and temporarily stored.

[0091] After the silicon carbide ceramics after sublimation are replaced twice, the diameter of the growth surface of the grown 4H-SiC ingot is 155 mm, and the growth length reaches 51 mm.

[0092] Example 4

[0093] The powder raw material is silicon carbide powder with a purity greater than 99.999% and a particle size of 48 μm and silicon powder with a purity of 99.999% and a particle size of 41 μm, and the mass ratio of the silicon powder to the silicon carbide powder is 5%. Using a mixer, stir for 8 hours to uniformly mix the silicon carbide powder and the silicon powder. Next, the uniformly mixed powder raw material is put into a mold and laid flat in the mold. Next, cover the upper cover plate of the mold and place a steel plate with the same dimensions as the mold on the upper cover plate of the mold. Use a pressure of 20 Mpa to compact the powder raw material. Further, take out the upper cover plate of the mold, put the mold containing the powder raw material into a vacuum high-temperature furnace for sintering, the sintering atmosphere is an argon gas atmosphere, and the sintering pressure is 7×10 4Set Pa and the sintering temperature to 1850 °C. After sintering for 20 hours, when the mold is cooled to room temperature, it is demolded and taken out to obtain a porous silicon carbide ceramic plate. Further, buff polishing treatment is performed on the surface of the porous silicon carbide ceramic plate to smooth its surface, and the surface of the porous silicon carbide ceramic plate is purged with nitrogen gas having a purity greater than 99.99% at 0.02 Mpa. The thickness of the manufactured porous silicon carbide ceramics is 34 mm.

[0094] A 3C-SiC seed crystal with a diameter of 40 mm is prepared using the chemical vapor deposition (CVD) method, and it is adhesively fixed to the top cover of the growth chamber (for example, the lid of a graphite crucible). Specifically, first, sucrose, which is an adhesive, is evenly spread on the inside of the lid of the graphite crucible, and then it is placed in a muffle furnace. First, it is heated to 150 °C and kept warm for 5 h, then the temperature is raised to 200 °C and kept warm for 7 h. Further, the 3C-SiC seed crystal is placed inside the lid of the graphite crucible where sucrose is evenly spread, and it is ensured that the 3C-SiC seed crystal is concentric with the lid of the graphite crucible. Then, a single silicon carbide wafer with the same size as the 3C-SiC seed crystal and in good condition is placed on the 3C-SiC seed crystal, and further, a stainless steel block with a diameter of 40 mm and a thickness of 20 mm is pressed on the single silicon carbide wafer. Next, the whole is placed in a muffle furnace, heated to 380 °C and kept warm for 5 h, and taken out after it is slowly cooled to room temperature.

[0095] Place a single porous silicon carbide ceramic in the growth chamber. The growth plane direction of the 3C-SiC seed crystal is the

[0001] direction. Adjust the vertical distance between the seed crystal and the porous silicon carbide ceramic plate to 30 mm.

[0096] Heat the growth chamber to raise its temperature to 1850°C, and the temperature of the lid of the graphite crucible rises to 1765°C. Place two pieces of porous silicon carbide ceramics (precursor raw materials) in the first region and raise the temperature to 1700°C, and heat the second region to a temperature of 1700°C. The growth atmosphere is argon gas, and the pressure in the crystal growth process of the growth chamber, the first region, and the second region is maintained at 10 Torr. After the porous silicon carbide ceramics have sublimated and decomposed for 20 hours, replacement is carried out. Before replacement, first heat the first region to the same temperature as the growth chamber (i.e., 1850°C) and keep it warm for 1 hour. When carrying out replacement, control the driving member to slowly push one piece of porous silicon carbide ceramics (precursor raw material) in the first region forward into the growth chamber, and set the propulsion speed to 100 mm / h. After completely pushing the porous silicon carbide ceramics to be replaced into the growth chamber, sublime and decompose it for 20 hours and then carry out replacement. The sublimated porous silicon carbide ceramics after replacement are pushed into the second region and temporarily stored.

[0097] After replacing the sublimated silicon carbide ceramics twice, the diameter of the growth surface of the grown 3C-SiC ingot is 40.3 mm, and the growth length reaches 87 mm.

[0098] The beneficial effects that can be generated by the embodiments of the present application include, but are not limited to, the following: (1) The embodiments of the present application can grow crystals with large dimensions and high quality by replacing the target raw material after sublimation with the candidate raw material based on the physical vapor transport method; (2) The embodiments of the present application use bulk materials as raw materials, have a high material utilization rate, can be easily transported and replaced, and do not generate dust during the growth process to contaminate the crystal growth; (3) When growing silicon carbide crystals, the embodiments of the present application can mix silicon carbide powder and silicon powder in a predetermined ratio to prepare the target raw material and / or candidate raw material, which can not only enhance the adhesiveness of the silicon carbide powder body, but also improve the utilization rate of the target raw material and / or candidate raw material, and avoid the decrease in its sublimation rate due to the solid-phase component C generated by the sublimation and decomposition of silicon carbide.

[0099] Note that the beneficial effects that may occur in different embodiments are different. In different embodiments, the beneficial effects that may occur may be any one or more combinations of the above, or any other achievable beneficial effects.

[0100] The above has explained the basic concept. Obviously, for those skilled in the art, the above detailed disclosure is merely exemplary and does not limit the present application. Although not explicitly explained here, those skilled in the art may make various modifications, improvements, and corrections to the present application. Such modifications, improvements, and corrections are recommended in the present application. Therefore, such modifications, improvements, and corrections still belong to the spirit and scope of the exemplary embodiments of the present application.

[0101] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to certain features, structures, or characteristics related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "an embodiment" or "one embodiment" or "one alternative embodiment" mentioned two or more times at different positions in this specification does not necessarily refer to the same embodiment. Also, some features, structures, or characteristics in one or more embodiments of the present application can be appropriately combined.

[0102] Also, unless clearly stated in the claims, the order of process elements and sequences, the use of numbers, letters, or other names described in this application are not for limiting the order of the processes and methods of this application. Although several presently useful invention embodiments have been considered by way of various examples in the above disclosure, as is understood, such details are for illustrative purposes only. The appended claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that conform to the essence and scope of the embodiments of this application. For example, the system assembly described above may be implemented by a hardware device, or may be implemented by a software solution only, for example, installing the described system on an existing server or mobile device.

[0103] Similarly, it should be noted that, in order to simplify the expressions disclosed in this application and make one or more invention embodiments easier to understand, in the above description of the embodiments of this application, multiple features may be grouped into one embodiment, drawing, or description thereof. However, such a disclosure method does not mean that the features necessary for the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are fewer than all the features of the single embodiment disclosed above.

[0104] In some embodiments, numbers are used to describe the number of components and attributes. As will be understood, the numbers used to describe such embodiments are modified in some instances by the modifiers "about", "approximate" or "substantially". Unless otherwise specified, "about", "approximate" or "substantially" indicate that a change of ±20% is allowed for the said numbers. Correspondingly, in some embodiments, all numerical parameters used in the specification and claims are approximate values, and such approximate values may be changed according to the characteristics required by individual embodiments. In some embodiments, numerical parameters should use a method of retaining general digits in consideration of the specified significant digits. The numerical fields and parameters for confirming the scope in some embodiments of the present application are approximate values, but in specific embodiments, such numerical settings are made as accurately as possible within the executable range.

[0105] Regarding each patent, patent application, patent application publication and other materials incorporated by reference in the present application, such as articles, books, specifications, publications, documents, etc., all of their contents are incorporated into the present application by reference. Except for the filed history files that do not conform to or conflict with the content of the present application, and except for the files (currently or subsequently added to the present application) that limit the broadest scope of the claims of the present application. Note that where the descriptions, definitions and / or uses of terms in the attached materials of the present application do not conform to or conflict with the content described in the present application, they shall conform to the descriptions, definitions and / or uses of terms in the present application.

[0106] Finally, as will be understood, the embodiments described in the present application are merely for explaining the principles of the embodiments of the present application. Other variations may also fall within the scope of the present application. Accordingly, by way of example and not limitation, alternative arrangements of the embodiments of the present application may be considered to conform to the guidance of the present application. Correspondingly, the embodiments of the present application are not limited to the embodiments explicitly disclosed and described in the present application.

Claims

1. A crystal growth method, comprising: placing a seed crystal and a target raw material substance in a growth chamber of a crystal growth apparatus; growing a crystal by physical vapor transport based on the seed crystal and the target raw material substance; during the crystal growth process, determining whether a predetermined condition is satisfied, including that the crystal growth time reaches a predetermined time, the crystal growth rate reaches a first predetermined growth rate, and the sublimation rate of the target raw material substance reaches a predetermined sublimation rate; when the crystal growth time, the crystal growth rate, and the sublimation rate satisfy the predetermined condition, the candidate raw material substance placed in the first region of the crystal growth apparatus is pushed toward the sublimated target raw material substance in the growth chamber at a speed slower than the propulsion speed threshold of 160 mm / h by a control assembly, so that the candidate raw material substance is arranged in the growth chamber, the sublimated target raw material substance in the growth chamber leaves the growth chamber, and the sublimated target raw material substance is replaced by the candidate raw material substance by being provided in the second region of the crystal growth apparatus, thereby further growing the crystal by physical vapor transport based on the candidate raw material substance.

2. The crystal growth method according to claim 1, wherein the target raw material substance or the candidate raw material substance is a bulk material.

3. The crystal growth method according to claim 2, wherein the shape of the bulk material is a cube, a rectangular parallelepiped, or an irregular bulk.

4. The crystal growth method according to claim 2 or 3, wherein the thickness of the bulk material is smaller than a predetermined thickness threshold.

5. The crystal growth method according to any one of claims 2 to 4, wherein the thickness of the bulk material is 30 to 40 mm.

6. The target raw material substance and / or the candidate raw material substance is obtained by a treatment process, and the treatment process includes: performing one or more of pressure molding, sintering, buff polishing, and purging on a powder raw material substance to obtain the target raw material substance and / or the candidate raw material substance. The crystal growth method according to any one of claims 1 to 5.

7. The crystal growth method according to claim 6, wherein the treatment conditions for the sintering treatment are inert atmosphere conditions.

8. The crystal growth method according to any one of claims 1 to 7, wherein the temperature of the first region is lower than the temperature of the growth chamber, and the temperature difference between the first region and the growth chamber is smaller than a first predetermined temperature threshold.

9. The crystal growth method according to claim 8, further comprising pre-treating the candidate raw material substance within the first region, the pre-treatment including heating to the crystal sublimation temperature and holding for a predetermined time.

10. The crystal growth method according to any one of claims 1 to 9, wherein the control assembly controls the speed at which the candidate raw material substance propels the sublimated target raw material substance to be 100 to 150 mm / h.

11. The crystal growth method according to any one of claims 1 - 7, wherein the temperature of the second region is lower than the temperature of the growth chamber, and the temperature difference between the second region and the growth chamber is smaller than a second predetermined temperature threshold.

12. The crystal growth method according to any one of claims 1 to 11, wherein the crystal contains silicon carbide, aluminum nitride, zinc oxide, or zinc telluride.

13. A growth chamber in which a seed crystal and a target raw material substance are disposed inside, and crystals are grown by physical vapor transport based on the seed crystal and the target raw material substance; A sensor for detecting the crystal growth time, crystal growth rate, and sublimation rate of the target raw material substance; During the crystal growth process, when it is determined based on the detection output from the sensor that the crystal growth time has reached a predetermined time, the crystal growth rate has reached a first predetermined growth rate, and the sublimation rate of the target raw material substance has reached a predetermined sublimation rate, the driving member is controlled to operate, and by the driving member, the candidate raw material substance disposed in the first region of the crystal growth apparatus is pushed toward the sublimated target raw material substance in the growth chamber at a speed slower than a propulsion speed threshold of 160 mm / h, so that the candidate raw material substance is disposed in the growth chamber, the sublimated target raw material substance in the growth chamber moves away from the growth chamber, and is provided in the second region of the crystal growth apparatus, thereby replacing the sublimated target raw material substance with the candidate raw material substance, a controller; A crystal growth apparatus, characterized by comprising the above.

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