Concentration gradient crystal growth method and crystal growth system

Abstract

The invention provides a concentration gradient crystal growth method and a crystal growth system.The concentration gradient crystal growth method comprises the steps that according to preset crystal concentration change trend data, the real-time growth rate, obtained through a Czochralski method, of a currently-grown crystal and the chemical formula ratio for generating the crystal, the concentration gradient crystal is obtained; and calculating to obtain the real-time supply rate of each component raw material, and supplying the raw materials by controlling a valve of a material supply unit for supplying the raw materials to the crucible assembly, so as to obtain crystals with a preset crystal concentration change trend. Therefore, according to continuous material supplementation based on the real-time supplementation rate of each component raw material, crystals with gradually changed growth concentration and relatively long size can be obtained, and the growth cost is reduced; meanwhile, due to continuous material supplement, the crystal growth process is always carried out at the same position, the growth interface is stable, and the crystal quality is ensured.

Description

Technical Field

[0001] This application relates to the field of crystal growth technology, and more specifically, to a concentration-gradient crystal growth method and crystal growth system. Background Technology

[0002] In the traditional Czochralski process for growing Nd:YAG crystals, a single-charge method is typically used. As the crystal grows, the raw material is continuously consumed. However, due to the segregation coefficient of Nd ions (Nd ions) in the YAG matrix being approximately 0.2, the axial doping concentration naturally increases from beginning to end during single-charge growth due to the "axial segregation" effect, resulting in an uncontrollable concentration distribution. This makes it difficult to actively grow functional crystals with a predetermined concentration gradient—such as a uniform or specific gradient distribution. Furthermore, the crystal's growth length is limited by the initial charge in the crucible. To obtain longer crystals, a larger crucible must be used, and a large amount of high-purity raw material must be loaded at once. This not only increases the raw material cost and equipment burden for a single growth cycle but also affects the quality of the latter half of the crystal due to the continuous downward movement of the melt interface. Moreover, the continuous drop in the liquid level during crystal growth causes changes in the solid-liquid interface, leading to interface disorder and affecting crystal quality. Summary of the Invention

[0003] In order to at least overcome the above-mentioned shortcomings in the prior art, the purpose of this application is to provide a concentration-gradient crystal growth method, comprising:

[0004] Obtain pre-set crystal concentration change trend data; Obtain the weight data of the currently grown crystal obtained by the Czochralski method; The real-time growth rate of the crystal is determined based on the weight data; Based on the pre-set crystal concentration change trend data, the real-time growth rate, and the chemical formula ratio for generating the crystal, the real-time replenishment rate of each component raw material corresponding to the crystal is determined. The valve of the feeding unit that controls the supply of raw materials to the crucible assembly is used to feed each component raw material at the real-time feeding rate to obtain crystals with a preset crystal concentration change trend; wherein the melt level in the crucible assembly is always kept at the same height.

[0005] In one possible implementation, along the crystal axis of the crystal, the crystal with the predetermined crystal concentration variation trend is a crystal in which the concentration of the first component raw material gradually increases; The step of controlling the valve of the feeding unit that supplies raw materials to the crucible assembly to feed each component raw material at the real-time feeding rate to obtain a crystal with a preset crystal concentration change trend includes: controlling the valve to feed each component raw material at the real-time feeding rate to obtain a crystal with a gradually increasing concentration of the first component raw material along the crystal axis direction.

[0006] In one possible implementation, the crucible assembly includes a first crucible and a second crucible, the first crucible and the second crucible being nested together and communicating with each other, the first crucible being located inside the second crucible; The step of controlling the valve of the feeding unit that supplies raw materials to the crucible assembly, and feeding each component raw material at the real-time feeding rate to obtain crystals with a preset crystal concentration change trend, includes: The corresponding raw materials are added to the second crucible at the real-time replenishment rate, and the raw materials flow into the first crucible through the through hole.

[0007] This application also provides a crystal growth method, including: Obtain the weight data of the currently grown crystal obtained by the Czochralski method; The real-time growth rate of the crystal is determined based on the weight data; The real-time replenishment rate of each component raw material corresponding to the crystal is determined based on the real-time growth rate and the chemical formula ratio of the generated crystal. The valve of the feeding unit that controls the supply of raw materials to the crucible assembly is used to feed each component raw material at the real-time feeding rate to make the concentration of the crystal uniform throughout; wherein the melt level in the crucible assembly is always kept at the same height.

[0008] In one possible implementation, the crystal corresponds to a first component raw material and a second component raw material, the first component raw material being segregated along the axial direction of the crystal.

[0009] This application also provides a crystal growth system, including a crystal growth unit, a feeding unit, a detection unit, and a control unit; The crystal growth unit includes a pulling assembly and a crucible assembly, with the pulling assembly located above the open end of the crucible assembly; The feeding unit includes multiple feeding bins and multiple pipelines connected to each feeding bin, and each pipeline is equipped with a valve; The detection unit is used to monitor the weight of the crystal located on the lifting assembly in real time and generate weight data; The control unit is electrically connected to both the detection unit and the valve, and is used to receive the weight data and control the valve based at least on the weight data.

[0010] In one possible implementation, the crucible assembly includes a first crucible and a second crucible nested together and communicating with each other, the first crucible being located inside the second crucible; wherein the first crucible is used to grow the crystal, and the second crucible is used to replenish the raw material corresponding to the crystal.

[0011] In one possible implementation, the bottom of the first crucible is provided with at least four symmetrically distributed through holes for connecting the second crucible.

[0012] In one possible implementation, the control unit includes crystal growth software and a programmable logic controller (PLC); wherein the crystal growth software is used to determine the real-time growth rate of the crystal based on the weight data, and the PLC controls the valve based at least on the real-time growth rate.

[0013] In one possible implementation, the valve includes a precision metering valve.

[0014] Compared with the prior art, this application has the following beneficial effects: This application provides a concentration-gradient crystal growth method and system. The concentration-gradient crystal growth method calculates the real-time replenishment rate of each component material by using pre-set crystal concentration change trend data, the real-time growth rate of the currently grown crystal obtained by the Czochralski method, and the chemical formula ratio of the generated crystal. The material is then replenished by controlling the valves of the feeding unit supplying the material to the crucible assembly, thereby obtaining a crystal with a pre-set crystal concentration change trend. Thus, continuous feeding based on the real-time replenishment rate of each component material allows for the production of crystals with gradually varying concentrations and longer dimensions, reducing growth costs. Simultaneously, due to continuous feeding, the growth process always occurs at the same location, resulting in a stable crystal growth interface and ensuring crystal quality. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic flowchart of the concentration-gradient crystal growth method provided in this embodiment; Figure 2 This is a schematic flowchart of the crystal growth method provided in this embodiment; Figure 3 This is one of the structural schematic diagrams of the crystal growth system provided in this embodiment; Figure 4 This is the second schematic diagram of the crystal growth system provided in this embodiment.

[0017] Icons: Crystal growth system-10; Crystal growth unit-100; Clifting assembly-110; Crucible assembly-120; First crucible-121; Through hole-1211; Second crucible-122; Feeding unit-200; Feeding bin-210; Piping-220; Valve-230; First valve-231; Second valve-232; Third valve-233; Detection unit-300; Control unit-400; Crystal growth software-410; Programmable logic controller-420; Melt-800; Crystal-900; Crystal growth interface-910. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0023] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0024] The inventors discovered that in the traditional Czochralski method for growing Nd:YAG crystals, a single-loading method is typically used. As the crystal grows, the raw material is continuously consumed. However, because the segregation coefficient of Nd ions in the YAG matrix is ​​approximately 0.2, during single-loading growth, the axial doping concentration naturally increases from beginning to end due to the "axial segregation" effect, resulting in an uncontrollable concentration distribution. This makes it difficult to actively grow functional crystals with a predetermined concentration gradient—such as a uniform or specific gradient distribution. Furthermore, the crystal's growth length is limited by the initial load in the crucible. To obtain longer crystals, a larger crucible must be used, and a large amount of high-purity raw material must be loaded at once. This not only increases the raw material cost and equipment burden for a single growth cycle but also affects the quality of the latter half of the crystal due to the continuous downward movement of the melt interface. Moreover, during crystal growth, the liquid level continuously decreases, causing changes in the solid-liquid interface and resulting in interface disorder, which also affects crystal quality.

[0025] This application provides a concentration-gradient crystal growth method and crystal growth system. Please refer to [link / reference]. Figure 1 The concentration-gradient crystal growth method includes the following steps.

[0026] Step S11: Obtain the pre-set crystal concentration change trend data.

[0027] Optionally, this embodiment is applied to obtaining crystal 900 with a gradually changing concentration gradient.

[0028] For example, in this embodiment, crystal 900 is an Nd:YAG crystal, and the chemical formula of Nd:YAG crystal is as follows: 3(1-x) Y2O3+ 3x Nd2O3+ 5Al2O3→Y 6(1-x) Nd 6x Al10 O 24 It should be understood that the segregation coefficient of Nd ions is 0.2, meaning that at the crystal growth interface 910, only about 20% of the Nd ions in the melt 800 enter the crystal 900, while the remaining 80% are segregated back into the melt 800. Therefore, during the growth of Nd:YAG crystals, yttrium oxide and alumina are continuously consumed as crystals 900 are formed, and the relative content of neodymium oxide in the melt 800 continuously increases, resulting in a higher Nd ion concentration in the later-grown crystal 900 portion.

[0029] Since the relative contents of Nd ions, aluminum ions and yttrium ions are uncertain, it is not possible to directly obtain the crystal 900 with the pre-set crystal concentration change trend. In this embodiment, it is necessary to first pre-set the crystal concentration change trend data so that the crystal 900 can be obtained by software calculation during the subsequent crystal 900 growth process.

[0030] Step S12: Obtain the weight data of the currently grown crystal 900 obtained by the Czochralski method.

[0031] It should be noted that the concentration-gradient crystal growth method in this embodiment is based on the Czochralski method. Specifically, this method involves drawing crystals from the melt and growing them by pulling them, ensuring crystal uniformity by controlling the pulling and rotation rates.

[0032] Specifically, the weight data of the grown crystal 900 can be obtained through a weighing sensor.

[0033] In this embodiment, it is necessary to obtain real-time weight data of the grown crystal 900. Based on this weight data, the software can calculate the real-time content of each component raw material in the crucible assembly 120 corresponding to the grown crystal 900.

[0034] Step S13: Determine the real-time growth rate of the crystal 900 based on the weight data.

[0035] In this embodiment, based on the real-time growth rate of crystal 900, the real-time consumption of each component raw material in crucible assembly 120 can be obtained, thereby replenishing each component raw material in the subsequent feeding process so that the crystal growth process always takes place in the same position.

[0036] Step S14: Based on the pre-set crystal concentration change trend data, the real-time growth rate, and the chemical formula ratio for generating the crystal 900, determine the real-time replenishment rate of each component raw material corresponding to the crystal 900.

[0037] In this embodiment, based on the preset data of the crystal concentration change trend, the real-time growth rate, and the chemical formula ratio of the crystal 900 to be generated, the real-time replenishment rate corresponding to each component raw material can be calculated. Feeding materials based on the real-time replenishment rate can obtain the crystal 900 with a preset crystal concentration change trend.

[0038] For example, based on the chemical formula ratio of the Nd:YAG crystal, the ratio of the real-time replenishment rates corresponding to yttrium ions and aluminum ions at any moment is 3:5 (molar ratio).

[0039] Step S15: Control the valve 230 of the feeding unit 200 that supplies raw materials to the crucible assembly 120, and replenish each component raw material at the real-time replenishment rate to obtain the crystal 900 with a preset crystal concentration change trend; wherein, the liquid level of the melt 800 in the crucible assembly 120 always remains at the same height.

[0040] It should be noted that in this embodiment, the crystal growth interface 910 is located in the crucible assembly 120, and the feeding rate of the feeding unit 200 is controlled by the valve 230.

[0041] In this way, through continuous feeding based on the real-time replenishment rate of each component raw material, a crystal 900 with a gradually changing growth concentration and a relatively long size can be obtained, reducing the growth cost; at the same time, due to continuous feeding, the liquid level of the melt 800 in the crucible assembly 120 always remains at the same height, and the crystal growth interface 910 is stable, ensuring the quality of the crystal 900.

[0042] In a possible implementation manner, along the crystal axis direction of the crystal 900, the crystal 900 with the preset crystal concentration change trend is a crystal 900 in which the concentration of the first component raw material gradually increases.

[0043] It should be noted that the crystal 900 with a gradually changing concentration gradient can be used to form some optical devices. For example, in the longitudinal concentration gradient design of the crystal 900 applied in a pump laser, the pump light can be more fully absorbed and utilized when in use.

[0044] Step S15 includes: controlling the valve 230 to replenish each component raw material at the real-time replenishment rate to obtain the crystal 900 in which the concentration of the first component raw material gradually increases along the crystal axis direction.

[0045] For example, the aforementioned crystal 900 is a Nd:YAG crystal, and its chemical composition can be expressed as Y 6(1-x) Nd 6x Al 10 O 24 , and the value range of the parameter x is 0 < x < 0.12, corresponding to the initial doping level of the first component raw material - Nd ions in the formulation.

[0046] In related technologies, due to the segregation effect, the Nd ion concentration inside the grown crystal 900 is not uniformly distributed, but gradually increases along the crystal axis of the crystal 900.

[0047] Therefore, in this embodiment, the crystal concentration change trend is first preset, and then the real-time replenishment rates of Nd ions, aluminum ions and yttrium ions are calculated by software to obtain crystal 900 in which the concentration of Nd ions gradually increases along the crystal axis.

[0048] Specifically, when the crystal 900 is formed by the method in this embodiment, the Nd ion concentration at the head is 1.1 at, the maximum concentration at the tail is 2.4 at, and the maximum head-tail concentration difference is 1.3 at.

[0049] It should be noted that, in this embodiment, based on different application requirements, the concentration of the first component raw material gradually increases or decreases along the crystal axis during the crystal formation process using the concentration gradient crystal growth method in this application.

[0050] In one possible implementation, the crucible assembly 120 includes a first crucible 121 and a second crucible 122, wherein the first crucible 121 and the second crucible 122 are nested together and communicate with each other, and the first crucible 121 is located inside the second crucible 122.

[0051] Step S15 includes: feeding the corresponding component raw materials into the second crucible 122 at the real-time replenishment rate, with each component raw material flowing into the first crucible 121 through the through hole 1211.

[0052] In this embodiment, during the growth of crystal 900, the first crucible 121 serves as the main growth crucible, directly holding the melt 800 and the grown crystal 900; the second crucible 122 serves as a feed buffer crucible, receiving raw materials from the feed unit 200. The first crucible 121 and the second crucible 122 are connected through a through-hole 1211 to allow the melt 800 to flow smoothly into the first crucible 121 via the second crucible 122, avoiding thermal and compositional disturbances caused by the direct impact of the raw materials on the crystal growth interface 910, thus ensuring the stability of the crystal growth interface 910.

[0053] This application also provides a crystal growth method, please refer to... Figure 2 This includes the following steps.

[0054] Step S21: Obtain the weight data of the currently grown crystal 900 obtained by the Czochralski method.

[0055] It should be noted that the crystal growth method in this embodiment is based on the Czochralski method. Specifically, this method involves drawing crystals from the melt and growing them by pulling them, ensuring the uniformity of the crystal by controlling the pulling and rotation rates.

[0056] Specifically, the weight data of the grown crystal 900 can be obtained through a weighing sensor.

[0057] In this embodiment, it is necessary to obtain real-time weight data of the grown crystal 900. Based on this weight data, the software can calculate the content of each component raw material in the crucible assembly 120 corresponding to the grown crystal 900.

[0058] Step S22: Determine the real-time growth rate of the crystal 900 based on the weight data.

[0059] Step S23: Based on the real-time growth rate and the chemical formula ratio of the generated crystal 900, determine the real-time replenishment rate of each component raw material corresponding to the crystal 900.

[0060] In this embodiment, based on the consumption amount and chemical formula ratio of the raw materials corresponding to crystal 900, the real-time consumption amount of each component raw material in crucible assembly 120 can be obtained, thereby replenishing the consumed component raw materials in the subsequent feeding process, thus ensuring that the growth process of crystal 900 always takes place in the same position and the crystal growth interface 910 remains stable.

[0061] Step S24: Control the valve 230 of the feeding unit 200 that supplies raw materials to the crucible assembly 120, and feed each component raw material at the real-time feeding rate to make the concentration of the crystal 900 uniform throughout; wherein the liquid level of the melt 800 in the crucible assembly 120 is always kept at the same height.

[0062] It should be noted that in this embodiment, the crystal growth interface 910 is located inside the crucible assembly 120, and the feeding rate of the feeding unit 200 is controlled by the valve 230.

[0063] For example, in the formation of Nd:YAG crystals, in order to make full use of the raw materials and ensure the stability of the crystal growth interface 910, it is necessary to calculate the real-time growth rate of the grown crystal 900 in real time, obtain the real-time supply rate of each component raw material, and ensure that neodymium oxide, aluminum oxide, and yttrium oxide are properly arranged in the crucible assembly 120. In this way, not only can crystal 900 with uniform Nd ion concentration be generated, but its length can also be increased while reducing costs.

[0064] Thus, continuous feeding based on the real-time replenishment rate of each component raw material can produce crystals 900 with uniform growth concentration and relatively long size, reducing growth costs. At the same time, due to continuous feeding, the melt 800 liquid level in the crucible assembly 120 is always kept at the same height, the crystal growth interface 910 is stable, and the quality of crystal 900 is guaranteed.

[0065] In one possible implementation, the crystal 900 corresponds to a first component raw material and a second component raw material, wherein the first component raw material is segregated along the axial direction of the crystal 900.

[0066] In related technologies, crystal 900 is usually grown using a one-time loading method. Due to the segregation effect of the first component raw material, the concentration of each component raw material inside the grown crystal 900 is not uniformly distributed, but gradually increases along the crystal axis of the crystal 900.

[0067] Therefore, in order to achieve uniform concentration throughout the crystal 900, it is necessary to determine the real-time replenishment rate of each component raw material based on the real-time growth rate and chemical formula ratio of the crystal 900, so that the chemical composition and liquid level of the melt 800 in the crucible assembly 120 are consistent with the initial growth state of the crystal 900.

[0068] For example, the aforementioned crystal 900 is an Nd:YAG crystal, and its chemical composition can be represented as Y 6(1-x) Nd 6x Al 10 O 24 The first component raw material is neodymium oxide, and the second component raw materials are aluminum oxide and yttrium oxide. The segregation coefficient of Nd ions is 0.2, meaning that at the crystal growth interface 910, only about 20% of the Nd ions in the melt 800 enter the crystal 900, while the remaining 80% are segregated back into the melt 800. To achieve uniform concentration throughout the crystal 900, the consumed neodymium oxide, aluminum oxide, and yttrium oxide need to be replenished to the crucible assembly 120 in real time, so that the content of neodymium oxide, aluminum oxide, and yttrium oxide in the crucible assembly 120 is consistent with the initial state of Nd:YAG crystal growth.

[0069] This application also provides a crystal growth system 10, please refer to... Figure 3 It includes a crystal growth unit 100, a feeding unit 200, a detection unit 300, and a control unit 400.

[0070] In this embodiment, the integrated system design enables precise control of the crystal growth process. For example, it is suitable for preparing Nd:YAG crystals with uniform or specific gradient doping distributions.

[0071] The crystal growth unit 100 includes a pulling assembly 110 and a crucible assembly 120, with the pulling assembly 110 located above the open end of the crucible assembly 120.

[0072] Specifically, the lifting assembly 110 consists of a seed crystal rod and a lifting and rotating drive mechanism, located directly above the opening end of the crucible assembly 120, and is used to clamp the seed crystal and perform lifting and rotating operations, thereby allowing the crystal 900 to gradually grow from the melt 800.

[0073] The feeding unit 200 includes a plurality of feeding bins 210 and a plurality of pipes 220 respectively connected to each of the feeding bins 210, and each of the pipes 220 is provided with a valve 230.

[0074] In this embodiment, the feeding unit 200 includes a plurality of independent feeding bins 210, each feeding bin 210 being dedicated to storing a high-purity raw material component.

[0075] For example, please refer to Figure 4 When preparing Nd:YAG crystal 900, multiple independent feed chambers 210 are used to hold yttrium oxide, aluminum oxide, and neodymium oxide, respectively. Simultaneously, an independent conduit 220 is led from each feed chamber 210 to the crucible assembly 120 of the crystal growth unit 100. Adjustable first valve 231, second valve 232, and third valve 233 are installed on each conduit 220 to manage the delivery of the corresponding raw materials. The valves 230 can adjust the flow rate of the raw materials under the control of the control unit 400.

[0076] The detection unit 300 is used to monitor the weight of the crystal 900 located on the lifting assembly 110 in real time and generate weight data.

[0077] Specifically, the detection unit 300 includes a high-precision weighing sensor associated with the seed crystal rod of the lifting assembly 110. This sensor is capable of continuously measuring the real-time weight of the grown crystal 900 and converting this dynamically changing weight data into an electrical signal output to the control unit 400.

[0078] The control unit 400 is electrically connected to the detection unit 300 and the valve 230 respectively, and is used to receive the weight data and control the valve 230 based on the weight data.

[0079] In this embodiment, the control unit 400 receives continuous weight data from the detection unit 300 and calculates the real-time crystal 900 growth rate using an internal algorithm. Based on this real-time growth rate and the preset target crystal 900 chemical composition, the control unit 400 generates corresponding control commands to adjust the flow rate of the valves 230 on each pipeline 220, thereby controlling the instantaneous replenishment flow rate of different raw materials and realizing synchronous closed-loop control of the crystal 900 growth process and the feeding operation.

[0080] Thus, based on continuous feeding, crystals 900 with gradually varying or uniform growth concentration and relatively long dimensions can be obtained, reducing growth costs. At the same time, due to continuous feeding, the crystal 900 grows at the same position in the crucible assembly 120, and the crystal growth interface 910 is stable, ensuring the quality of the crystal 900.

[0081] In one possible implementation, please refer to Figure 3 The crucible assembly 120 includes a first crucible 121 and a second crucible 122 nested together and communicating with each other, wherein the first crucible 121 is located inside the second crucible 122; wherein the first crucible 121 is used to grow the crystal 900, and the second crucible 122 is used to replenish the raw materials corresponding to the crystal 900.

[0082] In this embodiment, the first crucible 121 serves as the main growth crucible, directly holding the melt 800 and the grown crystal 900; the second crucible 122 serves as a feed buffer crucible, receiving raw materials from the feed unit 200. The cavities of the first crucible 121 and the second crucible 122 are connected to facilitate the exchange of melt 800. Thus, the replenished raw materials flow smoothly from the second crucible 122 into the first crucible 121, avoiding thermal and compositional disturbances caused by direct impact of the raw materials on the crystal growth interface 910, and ensuring the stability of the growth interface.

[0083] In one possible implementation, the bottom of the first crucible 121 is provided with at least four symmetrically distributed through holes 1211, which are used to connect the second crucible 122.

[0084] In this embodiment, a plurality of through holes 1211 can be provided at the bottom of the first crucible 121. The plurality of through holes 1211 are used to allow the flow of melt 800 between the first crucible 121 and the second crucible 122. In this way, the melt 800 in the first crucible 121 used for growing crystal 900 has a gentle surface, which can improve the quality of crystal 900 growth and avoid the reduction in quality of crystal 900 caused by instability of crystal growth interface 910 during the growth process.

[0085] In one possible implementation, please refer to Figure 3The control unit 400 includes crystal 900 growth software 410 and programmable logic controller 420; wherein, the crystal 900 growth software 410 is used to determine the real-time growth rate of the crystal 900 based on the weight data, and the programmable logic controller 420 controls the valve 230 based at least on the real-time growth rate.

[0086] In this embodiment, the crystal 900 growth software 410 processes the weight data from the detection unit 300, calculates and displays the real-time growth rate of the crystal 900 in real time, and calculates the real-time replenishment rate required for each raw material based on the chemical formula of the crystal 900 and the preset axial concentration distribution. The programmable logic controller 420 controls the valves 230 on each pipeline 220 based on the real-time replenishment rate to accurately replenish each component raw material.

[0087] In one possible implementation, the valve 230 includes a precision metering valve.

[0088] In this embodiment, the precision metering valve can respond to signals from the control unit 400 to adjust the feeding rate of each component raw material. Thus, by compensating for the segregation effect, crystals 900 with uniform axial concentration or crystals 900 grown according to a preset concentration gradient are formed.

[0089] In summary, this application provides a concentration-gradient crystal growth method and crystal growth system. The method includes: acquiring pre-set crystal concentration change trend data; acquiring the weight data of the currently grown crystal 900 obtained by the Czochralski method; determining the real-time growth rate of the crystal 900 based on the weight data; determining the real-time replenishment rate of each component raw material corresponding to the crystal 900 based on the pre-set crystal concentration change trend data, the real-time growth rate, and the chemical formula ratio for generating the crystal 900; and controlling the valve 230 of the feeding unit 200 that supplies raw materials to the crucible assembly 120 to replenish each component raw material at the real-time replenishment rate to obtain a crystal 900 with a pre-set crystal concentration change trend. This method calculates the real-time replenishment rate of each component raw material and replenishes the raw materials by using pre-set crystal concentration change trend data, real-time growth rate, and the chemical formula ratio for generating the crystal 900, thereby obtaining a crystal 900 with a gradually increasing growth concentration. Thus, continuous feeding based on the real-time replenishment rate of each component raw material can produce crystals 900 with gradually varying growth concentrations and longer dimensions, reducing growth costs. At the same time, due to continuous feeding, the growth process always takes place at the same location, and the crystal growth interface 910 is stable, ensuring the quality of crystal 900.

[0090] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0091] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for growing crystals with gradually varying concentrations, characterized in that, include: Obtain pre-set crystal concentration change trend data; Obtain the weight data of the currently grown crystal obtained by the Czochralski method; The real-time growth rate of the crystal is determined based on the weight data; Based on the pre-set crystal concentration change trend data, the real-time growth rate, and the chemical formula ratio for generating the crystal, the real-time replenishment rate of each component raw material corresponding to the crystal is determined. The valve of the feeding unit that controls the supply of raw materials to the crucible assembly is used to feed each component raw material at the real-time feeding rate to obtain crystals with a preset crystal concentration change trend; wherein the melt level in the crucible assembly is always kept at the same height.

2. The method according to claim 1, characterized in that, Along the crystal axis of the crystal, the crystal with the predetermined crystal concentration change trend is a crystal in which the concentration of the first component raw material gradually increases; The step of controlling the valve of the feeding unit that supplies raw materials to the crucible assembly, and feeding each component raw material at the real-time feeding rate to obtain crystals with a preset crystal concentration change trend, includes: The valve is controlled to supply each component raw material at the real-time supply rate to obtain crystals in which the concentration of the first component raw material gradually increases along the direction of the crystal axis.

3. The method according to claim 1, characterized in that, The crucible assembly includes a first crucible and a second crucible, the first crucible and the second crucible are nested and communicate with each other, and the first crucible is located inside the second crucible; The step of controlling the valve of the feeding unit that supplies raw materials to the crucible assembly, and feeding each component raw material at the real-time feeding rate to obtain crystals with a preset crystal concentration change trend, includes: The corresponding raw materials are added to the second crucible at the real-time replenishment rate, and the raw materials flow into the first crucible through the through hole.

4. A crystal growth method, characterized in that, include: Obtain the weight data of the currently grown crystal obtained by the Czochralski method; The real-time growth rate of the crystal is determined based on the weight data; The real-time replenishment rate of each component raw material corresponding to the crystal is determined based on the real-time growth rate and the chemical formula ratio of the generated crystal. The valve of the feeding unit that controls the supply of raw materials to the crucible assembly is used to feed each component raw material at the real-time feeding rate to make the concentration of the crystal uniform throughout; wherein the melt level in the crucible assembly is always kept at the same height.

5. The method according to claim 4, characterized in that, The crystal corresponds to a first component raw material and a second component raw material, and the first component raw material is segregated along the axial direction of the crystal.

6. A crystal growth system, characterized in that, It includes a crystal growth unit, a feeding unit, a detection unit, and a control unit; The crystal growth unit includes a pulling assembly and a crucible assembly, with the pulling assembly located above the open end of the crucible assembly; The feeding unit includes multiple feeding bins and multiple pipelines connected to each feeding bin, and each pipeline is equipped with a valve; The detection unit is used to monitor the weight of the crystal located on the lifting assembly in real time and generate weight data; The control unit is electrically connected to both the detection unit and the valve, and is used to receive the weight data and control the valve based at least on the weight data.

7. The crystal growth system according to claim 6, characterized in that, The crucible assembly includes a first crucible and a second crucible nested together and connected to each other, with the first crucible located inside the second crucible; wherein, the first crucible is used to grow the crystal, and the second crucible is used to replenish the raw materials corresponding to the crystal.

8. The crystal growth system according to claim 7, characterized in that, The bottom of the first crucible has at least four symmetrically distributed through holes, which are used to connect to the second crucible.

9. The crystal growth system according to claim 6, characterized in that, The control unit includes crystal growth software and a programmable logic controller (PLC); wherein the crystal growth software is used to determine the real-time growth rate of the crystal based on the weight data, and the PLC controls the valve based at least on the real-time growth rate.

10. The crystal growth system according to claim 6, characterized in that, The valve includes a precision metering valve.

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