Crystal growth apparatus and method

Abstract

Embodiments of the present application provide a crystal growth device and method. The crystal growth device comprises a holding furnace, a crucible, a heater and a growth platform. The crucible and the heater are arranged in the holding furnace. The crucible has an accommodating cavity in the interior. The accommodating cavity comprises a first section and a second section arranged along the direction of gravity and connected in series. The first section is located above the second section. The heater is located at the outer circumferential side of the first section. The heater is used to heat the molten zone material located in the first section. The solid polycrystalline raw material is in contact with the molten zone material to form a dissolution interface. The dissolution interface is located in the first section. The growth platform is slidingly connected with the crucible along the direction of gravity and extends into the second section. The growth platform is used to support the crystal. The crystal is in contact with the molten zone material to form a crystal growth interface. The crystal growth interface is located in the second section. The cross-sectional area of the first section perpendicular to the direction of gravity is greater than the cross-sectional area of the second section perpendicular to the direction of gravity. The technical solution provided by the present application can improve the crystal growth efficiency while ensuring the quality of the crystal.

Description

Technical Field

[0001] This application relates to the field of single crystal preparation technology, and more specifically, to a crystal growth apparatus and method. Background Technology

[0002] In the field of crystal growth, the cross-sectional areas of the dissolution interface and the crystal growth interface in traditional apparatuses are usually kept essentially the same. This design results in the dissolution rate of the solid polycrystalline feedstock being unable to effectively match the melt consumption requirements during crystal growth. When the growth rate increases, the molten zone shrinks continuously or even stops due to insufficient feedstock supply, leading to uneven melt supply and instability of the solid-liquid interface. Interface instability further causes defects such as component segregation, interface bending, and parasitic nucleation, severely affecting crystal quality. At the same time, the dynamic fluctuations in the molten zone volume disrupt the stability of the thermal field distribution and solute concentration, exacerbating the accumulation of internal stress and the formation of micro-defects in the crystal, ultimately leading to decreased crystal integrity, poor homogeneity, and deterioration of electrical properties. Summary of the Invention

[0003] This application provides a crystal growth apparatus and method that can improve crystal growth efficiency while ensuring crystal quality.

[0004] This application is achieved through the following technical solution:

[0005] In a first aspect, embodiments of this application provide a crystal growth apparatus, which includes a holding furnace, a crucible, a heater, and a growth platform. The crucible is disposed within the holding furnace and has an internal cavity for accommodating molten material and solid polycrystalline raw material. The cavity includes a first section and a second section arranged along the direction of gravity. The first section is located above and communicates with the second section. The cross-sectional area of ​​the first section perpendicular to the direction of gravity is larger than that of the second section perpendicular to the direction of gravity. The solid polycrystalline raw material contacts the molten material to form a dissolution interface, which is located within the first section. The heater is disposed within the holding furnace and located on the outer periphery of the first section. The heater is used to heat the molten material located in the first section. The growth platform is slidably connected to the crucible along the direction of gravity and extends into the second section. The growth platform is used to support the crystal. The crystal contacts the molten material to form a crystal growth interface, which is located within the second section.

[0006] In the technical solution of this application embodiment, by designing the first section of the receiving cavity to have a larger cross-sectional area than the second section, the dissolution interface area is effectively increased to improve the dissolution rate of the solid polycrystalline raw material, ensuring sufficient melt supply and maintaining dynamic stability of the molten zone. This avoids interface instability and related defects, and has advantages such as improving the dissolution rate of solid polycrystalline raw materials, maintaining molten zone stability, reducing crystal growth defects, and improving crystal quality. Furthermore, adapting to the aforementioned differentially designed receiving cavity, the heater in this application is fixed to maintain the molten zone within the crucible, and continuous crystal growth is achieved by moving the growth platform. This avoids dynamic instability of the molten zone volume caused by heater movement, improves the stability of the molten zone volume and the uniformity of the thermal field, thereby reducing interface bending and compositional segregation problems; while ensuring crystal growth efficiency, it also provides a guarantee for further optimization of crystal quality.

[0007] According to the first aspect, in one possible implementation, the ratio of the cross-sectional area of ​​the first segment perpendicular to the direction of gravity to the cross-sectional area of ​​the second segment perpendicular to the direction of gravity is 1.5:1 to 10:1.

[0008] A lower limit of 1.5:1 ensures a significantly larger dissolution interface area compared to the second stage, meeting basic dissolution efficiency requirements. An upper limit of 10:1 prevents excessive melt accumulation and flow control caused by an overly large first-stage cross-section, while ensuring a sufficient and uniform melt supply to the second-stage crystal growth region. This effectively reduces growth interruptions due to insufficient dissolution or interface instability caused by excessive melt, further improving the continuity and consistency of crystal growth. In the crystal growth apparatus, by limiting the ratio of the cross-sectional area of ​​the first stage perpendicular to the gravity direction to that of the second stage perpendicular to the gravity direction, the dissolution rate, crystal growth rate, and melt zone stability are balanced.

[0009] According to the first aspect, in one possible implementation, the receiving cavity includes a third segment along the direction of gravity, the third segment being located between and connecting the first segment and the second segment; the cross-sectional area of ​​the third segment perpendicular to the direction of gravity gradually decreases along the direction from the first segment to the second segment.

[0010] In the crystal growth apparatus, the gradient cross-section structure of the third section can guide the melt to flow smoothly from the first section with a large cross-section to the second section with a small cross-section, avoiding the impact of eddies and turbulence caused by abrupt changes in cross-section on the dissolution interface and the crystal growth interface, and maintaining the stability of the molten zone morphology; at the same time, it can guide the effective material in the melt to be transferred to the bottom along the direction of gravity, which is conducive to the full utilization of the effective material in the solid polycrystalline raw material.

[0011] According to the first aspect, in one possible implementation, the receiving cavity includes a fourth segment along the direction of gravity, the fourth segment being located below the second segment, the cross-sectional area of ​​the fourth segment perpendicular to the direction of gravity being greater than the cross-sectional area of ​​the second segment perpendicular to the direction of gravity; the outer peripheral surface of the growth platform is in sliding fit with the hole wall surface of the second segment, and there is a gap between the outer peripheral surface of the growth platform and the hole wall surface of the fourth segment.

[0012] In the crystal growth apparatus, the growth platform slides into the hole wall of the second section to limit the radial displacement of the growth platform, ensuring that the growth platform rises and falls smoothly along the direction of gravity and avoiding crystal eccentricity and tilting; the gap design of the fourth section can reduce the contact area between the growth platform and the crucible, thereby reducing heat loss and frictional resistance when the growth platform rises and falls.

[0013] According to the first aspect, in one possible implementation, the growth platform includes a base for supporting the crystal, the base being made of graphite.

[0014] By selecting a graphite base, the high-temperature conditions of crystal growth are adapted, reducing the risk of impurity introduction and ensuring crystal purity. Furthermore, the graphite base has good thermal conductivity, which can dissipate excess heat at the crystal growth interface and regulate the temperature gradient.

[0015] According to the first aspect, in one possible implementation, the growth platform includes a support base, one end of the base is connected to the support base, and the other end of the base extends into the second segment and is used to support the crystal, wherein the support base is made of ceramic material.

[0016] The ceramic support can provide rigid support under temperature-sensitive conditions, improving structural stability. Furthermore, the thermal conductivity of ceramic is much lower than that of graphite, which can reduce heat loss from the crystal growth region through the support and maintain the stability of the thermal field inside the crucible.

[0017] According to the first aspect, in one possible implementation, one of the base and the support is provided with a threaded post, and the other is provided with a mounting hole, wherein the threaded post is threadedly engaged with the mounting hole.

[0018] The threaded connection enables quick assembly and disassembly of the base and support, facilitating timely replacement of the base. Furthermore, the threaded connection ensures the positional accuracy and strength of the connection between the base and support.

[0019] According to the first aspect, in one possible implementation, the crystal growth apparatus further includes a temperature detection unit located inside the holding furnace and outside the crucible, the detection position of the temperature detection unit being at the same height as the crystal growth interface, and the heater responding to the temperature detection unit.

[0020] The detection position is at the same height as the crystal growth interface, which can directly reflect the temperature of the core growth area and avoid temperature misjudgment caused by detection deviation; the heater dynamically adjusts its power according to the detection signal to stabilize the crystal growth interface temperature in the optimal range, reducing dislocations, cracks and compositional segregation caused by temperature fluctuations; precise closed-loop temperature control improves the batch repeatability of crystal quality, reduces the probability of crystal growth failure caused by single parameter control, and improves production efficiency.

[0021] According to the first aspect, in one possible implementation, there is a gap between the temperature detection unit and the outer peripheral surface of the crucible.

[0022] The gap between the temperature detection unit and the crucible blocks the direct heat conduction path between the detection unit and the crucible wall, preventing the superposition of the crucible wall's own temperature from interfering with the radiation temperature detection of the crystal growth interface. This ensures that the detected value accurately reflects the true temperature of the crystal growth region, providing a reliable basis for the dynamic power adjustment of the heater and indirectly guaranteeing the temperature stability of the molten zone. Furthermore, the non-contact arrangement reduces the stress exerted on the crucible by external structures, avoiding contact friction or extrusion stress caused by equipment vibration and thermal expansion and contraction of the crucible. This reduces the risk of micro-cracks and deformation of the crucible due to external structural effects, while the stability of the crucible structure further ensures the integrity of the cavity shape and maintains the dynamic balance of the molten zone.

[0023] According to the first aspect, in one possible implementation, the crystal growth apparatus further includes a heat shield, which is fitted around the outer periphery of the crucible, and a mounting portion is provided on the side of the heat shield facing the crucible, wherein the heater is fixed to the mounting portion.

[0024] The heat shield can prevent heat from escaping from the crucible, reduce heat loss and temperature fluctuations, maintain a stable thermal field, and reduce heater energy consumption. The mounting section provides a rigid fixing point for the heater, ensuring that the heater is always aligned with the outer periphery of the first section. This fits the core design of fixing the heater to maintain the stability of the molten zone and avoids molten zone displacement caused by heater shifting. At the same time, it reduces heat radiation from the heater to the outside, improves heating efficiency, protects the heater from environmental pollution, and extends its service life.

[0025] According to the first aspect, in one possible implementation, the receiving cavity extends along the direction of gravity to the top of the crucible and forms a first opening, and the crystal growth apparatus includes a crucible plug that covers the first opening.

[0026] The top opening facilitates direct loading of solid polycrystalline raw materials and molten material, simplifying the operation process and improving loading efficiency. The crucible plug seal reduces heat loss at the top, preventing the temperature drop in the first stage from affecting the dissolution rate. It also isolates external air, preventing oxidation of the melt and crystal and ensuring crystal purity. The sealed structure reduces the loss of raw material due to high-temperature volatilization, improves raw material utilization, prevents volatiles from contaminating the equipment, and maintains stable gas pressure inside the crucible, preventing airflow disturbance of the dissolution interface and crystal growth interface, thus reducing the defect rate.

[0027] In a second aspect, embodiments of this application provide a crystal growth method applied to the crystal growth apparatus described in the first aspect, the crystal growth method comprising:

[0028] The molten material and solid polycrystalline raw material are loaded into the receiving cavity;

[0029] The molten material is heated by the heater.

[0030] The growth platform is moved downward relative to the crucible, causing the solid polycrystalline raw material to continuously dissolve into the molten zone material. At the same time, the substances in the molten zone material continuously precipitate on the growth platform to form crystals until crystal growth is completed.

[0031] In the technical solution of this application embodiment, the differentiated cross-sectional design of the device cavity is coordinated with the raw material distribution and growth platform movement in the crystal growth method: the first large cross-section expands the contact area between the solid polycrystalline raw material and the melting zone, significantly improving the dissolution rate; the second small cross-section makes the growth rate of the crystal interface relatively controllable, realizing the dynamic balance of "melt supply rate - crystal consumption rate", avoiding the growth rate limitation due to insufficient feeding or the melting zone expansion caused by excessive feeding, which not only ensures the growth efficiency, but also reduces defects such as component segregation and interface bending. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used 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.

[0033] Figure 1 This is a schematic diagram of the structure of the filling material inside the crystal growth apparatus provided in some embodiments of this application;

[0034] Figure 2 This is a schematic diagram of the structure of a crystal growth apparatus provided in some embodiments of this application;

[0035] Figure 3This is a schematic diagram of the structure of the filling material in the crystal growth apparatus provided in other embodiments of this application;

[0036] Figure 4 A schematic diagram illustrating the mating structure of the crucible and growth platform provided in other embodiments of this application;

[0037] Figure 5 A schematic diagram of the mating structure of the crucible and growth platform provided for some embodiments of this application;

[0038] Figure 6 A disassembled structural diagram of the growth platform provided in some embodiments of this application;

[0039] Figure 7 A schematic flowchart illustrating a crystal growth method provided in some embodiments of this application;

[0040] Figure 8 Schematic diagrams of the crystal growth apparatus provided in Comparative Examples 1 and 2 of this application;

[0041] Figure 9 This is a cross-sectional view of the crystal prepared in Example 1 of this application;

[0042] Figure 10 This is a cross-sectional view of the crystal prepared in Comparative Example 1 of this application;

[0043] Figure 11 This is a cross-sectional view of the crystal prepared in Example 2 of this application;

[0044] Figure 12 This is a cross-sectional view of the crystal prepared in Comparative Example 2 of this application.

[0045] Figure label:

[0046] 1000-Crystal growth apparatus; 100-Holding furnace; 200-Cruise; 210-Receiving cavity; 211-First section; 212-Second section; 213-Third section; 214-Fourth section; 300-Heater; 400-Growth platform; 410-Base support; 420-Support base; 431-Threaded column; 432-Mounting hole; 510-Dissolution interface; 520-Crystal growth interface; 600-Temperature detection unit; 700-Heat insulation cover; 710-Mounting part; 800-Cruise plug; 2001-Solid polycrystalline raw material; 2002-Melting zone material; 2003-Crystal. Detailed Implementation

[0047] To make this application clearer, specific embodiments are described below with reference to the accompanying drawings:

[0048] Please refer to Figure 1 and Figure 2The crystal growth apparatus 1000 includes a holding furnace 100, a crucible 200, a heater 300, and a growth platform 400. The crucible 200 is disposed inside the holding furnace 100 and has a receiving cavity 210 inside. The receiving cavity 210 is used to receive the molten material 2002 and the solid polycrystalline raw material 2001. The receiving cavity 210 includes a first section 211 and a second section 212 arranged along the direction of gravity. The first section 211 is located above and communicates with the second section 212. The cross-sectional area of ​​the first section 211 perpendicular to the direction of gravity is larger than the cross-sectional area of ​​the second section 212 perpendicular to the direction of gravity. Solid polycrystalline raw material 2001 comes into contact with molten material 2002 to form a dissolution interface 510, which is located within the first section 211. A heater 300 is disposed within the holding furnace 100 and located on the outer periphery of the first section 211. The heater 300 is used to heat the molten material 2002 located in the first section 211. A growth platform 400 is slidably connected to the crucible 200 along the direction of gravity and extends into the second section 212. The growth platform 400 is used to support the crystal 2003. The crystal 2003 comes into contact with molten material 2002 to form a crystal growth interface 520, which is located within the second section 212.

[0049] The holding furnace 100 has an outer enclosed structure, providing installation space for internal components, maintaining a stable temperature environment inside the furnace, reducing heat loss, and preventing temperature fluctuations from affecting the state of the molten material 2002 and the growth quality of the crystal 2003. The holding furnace 100 can adopt a multi-layer insulation design, such as graphite felt or ceramic fiber; the holding furnace 100 is sealed, and an inert protective gas, such as nitrogen or argon, can be introduced inside to prevent oxidation or volatilization of the raw materials.

[0050] The crucible 200 has a receiving cavity 210. The material of the crucible 200 is usually high-purity quartz, graphite, boron nitride, or other high-temperature resistant and chemically inert materials. The receiving cavity 210 can be understood as a spatial structure used to receive the molten material 2002 and the solid polycrystalline raw material 2001. The first segment 211 and the second segment 212 being located above the second segment 212 and connected to the second segment 212 means that the lower end of the first segment 211 and the upper end of the second segment 212 are connected to form a stepped direct connection structure, or a conical transition segment is used to connect the lower end of the first segment 211 and the upper end of the second segment 212. The cross-sectional area of ​​the first segment 211 perpendicular to the direction of gravity is greater than that of the second segment 212 perpendicular to the direction of gravity. This is achieved by designing the receiving cavity 210 as a combination of cavity segments with different geometric shapes. For example, a stepped structure with a larger diameter cylinder in the upper section and a smaller diameter cylinder in the lower section can be used, or a straight cylinder structure with a rectangular cross-section in the upper section and a smaller rectangular cross-section in the lower section can be used. Of course, the cross-sectional shapes of the first segment 211 and the second segment 212 perpendicular to the direction of gravity can be other regular or irregular geometric shapes, and this application does not limit this.

[0051] The heater 300 is located on the outer periphery of the first segment 211, which does not mean that the heater 300 completely covers the first segment 211 along the direction of gravity. Rather, it means that the heater 300 and the first segment 211 have a portion of overlap along the first direction. The heater 300 can be understood as a device for providing heat energy. The heater 300 can be made of resistance wire or use induction heating to heat the molten material 2002. Specifically, the position and power of the heater 300 can be adjusted according to actual needs to ensure that the molten material 2002 can obtain a uniform heat distribution.

[0052] The dissolution interface 510 is located within the first segment 211, meaning that the contact interface between the solid polycrystalline raw material 2001 and the molten material 2002 is confined within the first segment 211, ensuring that the dissolution process occurs in a larger cross-sectional area to fully respond to the melt consumption demand. The crystal growth interface 520 is located within the second segment 212, meaning that the contact interface between the crystal 2003 and the molten material 2002 is set in the second segment 212 region, in order to allow crystal 2003 growth in a smaller cross-sectional area to maintain the morphological stability of the solid-liquid interface.

[0053] The growth platform 400 and the crucible 200 are slidably connected along the direction of gravity, meaning that the growth platform 400 can move relative to the crucible 200 in the direction of gravity, i.e. Figure 1 and Figure 2 The growth platform 400 is moved up and down in the middle, and its position is dynamically adjusted during the growth of crystal 2003.

[0054] In the technical solution of this application embodiment, solid polycrystalline raw material 2001 and molten zone material 2002 are placed in the receiving cavity 210 of crucible 200. Solid polycrystalline raw material 2001 is located at the upper part of the first section 211, and molten zone material 2002 is located at the lower part of the first section 211 and the upper part of the second section 212. Seed crystal can be set at the top of the growth platform 400 and heater 300 can be started to heat part of the outer periphery of the first section 211 of crucible 200, so that the molten zone material 2002 in the first section 211 is kept in a molten state to form a molten zone. The molten zone extends upward to contact the solid polycrystalline raw material 2001 above to form a dissolution interface 510. The dissolution interface 510 is stable in the first section 211, and the solid polycrystalline raw material 2001 continuously dissolves at the dissolution interface to form a molten zone. The growth platform 400 is adjusted to its initial position, and the lower end of the molten material 2002 contacts the seed crystal on the growth platform 400. When the temperature at the contact point between the seed crystal and the molten material 2002 is lower than the melting point of the crystal material, the solute in the molten material 2002 is directionally solidified on the growth platform 400 to form crystal 2003. The contact interface between crystal 2003 and molten material 2002 is defined as the crystal growth interface 520, which is located within the second segment 212. The power of the heater 300 is kept stable while the growth platform 400 is slowly slid downward. During this process, the solid polycrystalline raw material 2001 continuously dissolves at the dissolution interface 510, replenishing the solute in the molten material 2002. The solute in the molten material 2002 diffuses or is transported to the bottom through the molten material 2002 and precipitates at the crystal growth interface 520. Crystal 2003 grows layer by layer until crystal 2003 of the target size is formed.

[0055] This application employs a differentiated design to distribute the cross-sectional area of ​​the receiving cavity 210, positioning the dissolution interface 510 in the first segment 211 with a large cross-section and the crystal growth interface 520 in the second segment 212 with a small cross-section. The first segment 211 and the second segment 212 are vertically connected along the direction of gravity. The large cross-section design of the first segment 211 correspondingly increases the contact area between the solid polycrystalline raw material 2001 and the molten material 2002, significantly improving the dissolution rate. The small cross-section design of the second segment 212 relatively reduces the growth rate of the crystal 2003, achieving a dynamic balance between melt consumption and replenishment. This design, by increasing the dissolution rate and precisely matching the melt consumption requirements of crystal 2003 growth, avoids limited growth rate and crystal 2003 quality defects caused by insufficient replenishment in the molten zone, while ensuring consistent growth interface stability, thus improving overall crystal growth efficiency.

[0056] Furthermore, by adapting the aforementioned cross-sectionally differentiated cavity 210, the heater 300 in this application is positioned fixed to maintain the molten zone within the crucible 200, and continuous growth of the crystal 2003 is achieved by moving the growth platform 400. This design avoids dynamic instability of the molten zone volume caused by the movement of the heater 300, improves the stability of the molten zone volume and the uniformity of the thermal field, thereby reducing interface bending and compositional segregation problems; while ensuring crystal growth efficiency, it also provides a guarantee for further optimization of the quality of the crystal 2003.

[0057] According to some embodiments of this application, please refer to Figure 1 and Figure 2 The ratio of the cross-sectional area of ​​the first segment 211 perpendicular to the direction of gravity to the cross-sectional area of ​​the second segment 212 perpendicular to the direction of gravity is 1.5:1 to 10:1.

[0058] The cross-sectional area ratio refers to the ratio of the cross-sectional area of ​​the first segment 211 perpendicular to the direction of gravity to the cross-sectional area of ​​the second segment 212 perpendicular to the direction of gravity. The ratio can be set to any value between 1.5:1 and 10:1, such as 2:1, 3:1, 4:1, 5:1 or 8:1. By increasing the difference between the area of ​​the dissolution interface 510 and the area of ​​the crystal growth interface 520, it is ensured that the dissolution rate of the solid polycrystalline raw material 2001 can efficiently match the consumption requirements of the molten zone material 2002, laying the foundation for improving both crystal growth efficiency and quality.

[0059] With a cross-sectional area ratio of 1.5:1 for the first segment 211 and the second segment 212, taking an inner diameter of φ30mm for the second segment 212 as an example, the cross-sectional area of ​​the second segment 212 is approximately 707mm², and the cross-sectional area of ​​the first segment 211 is approximately 1060mm². Under these conditions, the area of ​​the dissolution interface 510 is increased by approximately 50% compared to the traditional cylindrical crucible. Experimental data shows that, under stable heating power and a high-purity argon protective atmosphere, the growth platform 400 can be supported to move downwards at a speed of 0.8–1.2mm / h. Considering solidification shrinkage and dynamic equilibrium of the interface, the corresponding actual crystal growth rate is 0.7–1.1mm / h. Compared to the traditional cylindrical zone melting apparatus, under the premise of the same crystal growth interface 520 area, the maximum stable crystal growth rate is usually no more than 0.5mm / h due to limited dissolution capacity. The proposed solution increases the crystal growth rate by approximately 40% to 120%, significantly improving production efficiency.

[0060] With the cross-sectional area ratio of the first segment 211 to the second segment 212 being 10:1, taking the inner diameter of the second segment 212 as φ30mm as an example, the cross-sectional area of ​​the second segment 212 is approximately 707mm², and the cross-sectional area of ​​the first segment 211 is approximately 7070mm². At this time, the area of ​​the dissolution interface 510 is 10 times that of the crystal growth interface 520, which greatly increases the amount of solid raw material that can be dissolved per unit time. Based on the optimized thermal field distribution and the adoption of segmented heat preservation design, the growth platform 400 can achieve a maximum moving speed of 2.0mm / h; the corresponding actual crystal growth speed can reach 1.8mm / h–2.0mm / h.

[0061] Given that the temperature gradient field distribution below the molten zone is typically 5K / mm-15K / mm, the growth platform 400's moving speed of 2.0mm / h is the limit speed adapted to this temperature gradient field. This avoids the sudden cooling of crystal 2003 due to excessively fast moving speed, which could lead to quality problems such as lattice distortion and stress cracks. It also prevents a large amount of solid polycrystalline raw material 2001 from flooding into the molten zone, keeping the temperature fluctuation of the molten zone within ±2K and the volume fluctuation of the molten zone below 5%, thus ensuring the stability of the molten zone.

[0062] By limiting the ratio of the cross-sectional areas of the first segment 211 to the second segment 212 to a specific range of 1.5:1 to 10:1, the area of ​​the dissolution interface 510 is significantly larger than that of the crystal growth interface 520, thereby accelerating the dissolution process of the solid polycrystalline raw material 2001 and providing a continuous and stable melt supply to the molten zone. This ratio range is designed to balance dissolution rate and system stability, preventing insufficient feeding due to an excessively small ratio or thermal disturbances due to an excessively large ratio, ensuring a constant molten zone volume, and thus guaranteeing the uniformity of thermal field distribution and solute concentration.

[0063] Specifically, a lower limit of 1.5:1 ensures sufficient room for improvement in the area of ​​the dissolution interface 510, allowing the dissolution rate to cover the melt consumption requirements under high growth rates and avoiding crystal growth stagnation or rate decay caused by insufficient feeding. Conversely, an upper limit of 10:1 prevents uneven thermal field distribution and melt flow disturbances caused by excessive area differences, maintaining the thermal stability and solute uniformity of the crystal growth interface 520. This ratio range comprehensively considers both dissolution efficiency and interface control requirements, ensuring that the dissolution rate fully matches the growth rate while suppressing defects such as solid-liquid interface bending and parasitic nucleation, ultimately improving the integrity and uniformity of crystal 2003 growth.

[0064] According to some embodiments of this application, please refer to Figure 3 and Figure 4The cavity 210 includes a third segment 213. Along the direction of gravity, the third segment 213 is located between the first segment 211 and the second segment 212 and connects the first segment 211 and the second segment 212. The cross-sectional area of ​​the third segment 213 perpendicular to the direction of gravity gradually decreases along the direction from the first segment 211 to the second segment 212.

[0065] The third segment 213 refers to the transition region within the receiving cavity 210. Located between and connecting the first and second segments 211 and 212, this region ensures the melt must flow through this transition section, preventing interruption of the flow path. The cross-sectional area of ​​the third segment 213, perpendicular to the direction of gravity, gradually decreases along the direction from the first segment 211 to the second segment 212, indicating a continuous decrease in cross-sectional area. This can be achieved through linear or non-linear tapering. Specifically, the third segment 213 can be implemented using geometric shapes with smooth cross-sectional changes, such as a conical or parabolic tapering structure, transforming abrupt changes in cross-sectional area into continuous changes. This optimizes the solute transport path and prevents sudden increases in flow velocity or turbulence caused by abrupt changes in cross-sectional area during melt flow. Furthermore, it prevents solute deposition at abrupt changes in cross-sectional area, improving the utilization rate of the effective material in the solid polycrystalline raw material 2001.

[0066] By connecting the first section 211 and the second section 212 through the third section 213, the continuous change of cross-sectional area of ​​the melt, driven by gravity, from the first section 211 with a large cross-section to the second section 212 with a small cross-section, promotes a smooth transition of flow velocity. This avoids sudden changes in flow velocity and loss of kinetic energy caused by abrupt changes in cross-section, thereby maintaining the uniformity of the thermal field distribution and the stability of the solute concentration, and ensuring the morphological stability of the dissolution interface 510 and the crystal growth interface 520.

[0067] Please refer to Figure 4 and Figure 5 The third segment 213 can be designed as a conical transition segment with a smooth inner wall. The inner surface of the third segment 213 is a continuous curved surface to achieve a smooth transition of melt flow.

[0068] When the receiving cavity 210 has a first section 211, a second section 212, and a third section 213, the height of the upper end of the heater 300 is located in the area where the first section 211 is located, and the height of the lower end of the heater 300 is located at the connection between the second end and the third section 213 or in the area where the second end is located. That is, along the direction of gravity, the heater 300 overlaps with part of the first section 211 and all of the third section 213, and the heating can partially overlap with the second section 212. Thus, when the heater 300 is activated, a melting zone consisting of the lower part of the first section 211, the upper part of the second section 212, and the third section 213 can be formed in the receiving cavity 210.

[0069] In other embodiments, the first segment 211 and the second segment 212 may also be directly connected, and this application does not limit this.

[0070] According to some embodiments of this application, please refer to Figure 3 and Figure 4 The receiving cavity 210 includes a fourth segment 214 along the direction of gravity. The fourth segment 214 is located below the second segment 212. The cross-sectional area of ​​the fourth segment 214 perpendicular to the direction of gravity is larger than the cross-sectional area of ​​the second segment 212 perpendicular to the direction of gravity. The outer peripheral surface of the growth platform 400 is in sliding fit with the hole wall surface of the second segment 212. There is a gap between the outer peripheral surface of the growth platform 400 and the hole wall surface of the fourth segment 214.

[0071] The fourth segment 214 refers to a specific region added to the structure of the receiving cavity 210, which can be realized by using a cavity structure with a gradually changing cross-section design. The change in cross-sectional area can be achieved through methods such as tapered transition or stepped expansion.

[0072] The sliding fit between the outer peripheral surface of the growth platform 400 and the hole wall of the second section 212 refers to the axial sliding connection formed by the tight fit between the two. For example, the fit clearance between the outer peripheral surface of the growth platform 400 and the hole wall of the second section 212 can be 0.05mm to 0.1m, which can be achieved by using a high-precision machined fit surface to prevent the molten material 2002 from flowing from the gap between the growth platform 400 and the hole wall of the second section 212 into the fourth section 214. The fit height between the growth platform 400 and the hole wall of the second section 212 is certain to ensure that the crystal 2003 is stably supported in the second section 212 area and to maintain the flatness of the crystal growth interface 520.

[0073] It should be noted that during the growth of crystal 2003, although the growth platform 400 moves downward, it always maintains close contact with the inner wall of the hole in the second section 212.

[0074] The gap between the outer peripheral surface of the growth platform 400 and the hole wall of the fourth section 214 refers to the reserved annular gap. The fit gap between the outer peripheral surface of the growth platform 400 and the hole wall of the fourth section 214 is greater than or equal to 1 mm; that is, the growth platform 400 and the inner wall of the hole of the fourth section 214 do not come into direct contact.

[0075] By designing the receiving cavity 210 of the crucible 200 such that the second section 212 fits tightly with the growth platform 400 and the fourth section 214 has a reserved gap with the growth platform 400, on the one hand, the high-precision sliding fit between the second section 212 and the growth platform 400 constructs a sealing barrier in the area where the molten zone is located, completely preventing the molten material 2002 from leaking down to the fourth section 214, ensuring the stability of the molten zone volume, reducing material waste, and effectively avoiding inclusions, uneven composition, and other crystal growth defects in 2003; on the other hand, the continuous tight fit between the growth platform 400 and the hole wall of the second section 212 can reduce heat loss at the interface, limit the lateral heat diffusion range of the molten zone, ensure a uniform and stable temperature gradient at the crystal growth interface 520, provide a good thermodynamic environment for the ordered arrangement of crystal atoms in 2003, and significantly reduce the probability of the generation of crystal defects such as dislocations and twins in 2003. On the other hand, the annular gap formed by the large cross-section design of the fourth segment 214 ensures that the growth platform 400 only contacts the wall of the second segment 212 during its downward movement. This significantly reduces the contact area between the growth platform 400 and the crucible 200, thereby reducing axial sliding resistance, preventing growth interruption or interface disturbance caused by mechanical jamming, and ensuring the continuity and stability of the crystal 2003 growth process. It also reduces the heat conduction path through the crucible 200 wall, reducing ineffective heat conduction from the molten zone to the low-temperature region, thus saving energy and preventing crystal 2003 composition segregation caused by temperature fluctuations.

[0076] Furthermore, the stable support and height design of the second segment 212 for the growth platform 400 can effectively limit the disordered expansion of the radial growth of the crystal 2003, help maintain the preset external dimensions of the crystal 2003, significantly improve the yield and dimensional accuracy of the crystal 2003, and provide comprehensive protection for the stability of the crystal 2003 growth and the improvement of the crystal 2003 quality from a structural perspective.

[0077] According to some embodiments of this application, please refer to Figure 3 , Figure 4 and Figure 6 The growth platform 400 includes a base 410 for supporting the crystal 2003, and the base 410 is made of graphite.

[0078] The base 410, as the core support component in the growth platform 400 that directly contacts the crystal 2003, can be made of graphite. Graphite possesses excellent structural stability and chemical inertness at extreme high temperatures: in the high-temperature environment of crystal 2003 growth, it can effectively resist deformation caused by thermal stress, ensuring the stability of the support structure, and avoid adverse reactions with molten materials, thus mitigating the risk of contamination at the contact interface. In practical applications, the base 410 can keep the crystal growth interface 520 in a fixed position throughout the growth process, while simultaneously achieving uniform heat conduction, thereby reducing the adverse effects of local temperature fluctuations on the orderly growth of the crystal 2003.

[0079] The graphite materials include various types such as molded graphite, calcined graphite, and isostatic graphite. This application does not impose special restrictions on the specific preparation process of graphite, and can flexibly select according to the actual needs of crystal growth.

[0080] Designing the base 410 as graphite material can fully leverage its material properties: on the one hand, the excellent thermal conductivity of graphite allows heat to be quickly and evenly distributed on the surface of the base 410, effectively suppressing the generation of local temperature gradients and avoiding crystal 2003 defects caused by interface fluctuations; on the other hand, the chemical inertness of graphite in high-temperature environments can block potential reaction paths with molten polycrystalline raw materials, eliminating the risk of impurity contamination from the source.

[0081] In some embodiments, the base 410 is made of high-purity graphite and is a disc structure. The surface of the base that contacts the crystal 2003 is finely polished. The base 410 is directly integrated into the support structure of the growth platform 400 to ensure support strength and installation stability, and further improve the reliability of the crystal 2003 growth process.

[0082] According to some embodiments of this application, please refer to Figure 3 and Figure 4 The growth platform 400 includes a support base 420, one end of a base 410 is connected to the support base 420, and the other end of the base 410 extends into the second section 212 and is used to support the crystal 2003. The support base 420 is made of ceramic.

[0083] The support base 420, as the core structural support component of the growth platform 400, bears the main mechanical load-bearing function. The support base 420 is made of ceramic material, possessing excellent high-temperature stability and structural rigidity. Specifically, it can be made of alumina ceramic, silicon nitride ceramic, or silicon carbide ceramic. The ceramic support base 420 provides a stable and rigid frame for the growth platform 400, effectively resisting bending and deformation caused by the accumulation of thermal stress during crystal 2003 growth, ensuring the dimensional stability of the overall structure.

[0084] The connection between the base 410 and the support 420 can be achieved through mechanical fixing or chemical bonding, specifically including snap-fit, tenon and mortise connection, or high-temperature adhesive bonding. This connection structure must meet the robust constraint requirements under high-temperature environments to ensure that the graphite base 410 does not shift during the dynamic growth of the crystal 2003, effectively resisting the influence of external forces such as melt buoyancy and equipment vibration, and ensuring the positional stability of the crystal growth interface 520.

[0085] The ceramic support 420 and the graphite base 410 work together. The difference in thermal expansion coefficients between the two materials is buffered by the flexible design of the connection structure, allowing for slight relative displacement during thermal expansion. This absorbs the thermal stress caused by temperature changes and prevents damage such as deformation or cracking of the base 410. Simultaneously, the design of the base 410 extending into the second section 212 to support the crystal 2003 utilizes the high thermal conductivity of graphite to achieve uniform heat transfer from the growth region to the support 420, maintaining the thermal stability at the crystal growth interface 520. Meanwhile, the rigid support of the ceramic support 420 ensures the positional accuracy of the growth platform 400 during axial sliding, preventing interface disturbances caused by vibration or displacement. This balances heat conduction requirements with structural stability, creating a stable thermodynamic environment for the growth of the crystal 2003.

[0086] In practical applications, both the base 410 and the support 420 can be designed as columnar structures, and they can be coaxially arranged to ensure uniform force distribution and accurate positioning. In addition, the base 410 can also be a graphite coating on the upper surface of the support 420. This application does not limit the specific structural form of the support 420.

[0087] Furthermore, the end of the support base 420 furthest from the base 410 can extend outside the holding furnace 100 and connect with the external drive mechanism. This application does not limit the specific form of the external drive mechanism; for example, it can be driven directly by a linear motor, driven by a rotary motor in conjunction with a gear and rack, or driven by a rotary motor in conjunction with a lead screw and nut, etc., as long as it can achieve bidirectional stable movement of the support base 420, i.e., driving downwards to complete the crystal 2003 growth and resetting upwards to the initial position to meet the usage requirements.

[0088] Based on the above embodiments, the end of the support base 420 away from the base 410 is provided with a radially outwardly extending stop. When the support base 420 moves upward to reset, the stop can form a limiting fit with the outer wall surface of the holding furnace 100, mechanically limiting the maximum upward stroke of the support base 420, preventing the support base 420 from completely entering the receiving cavity 210, and ensuring the safety and structural rationality of the equipment operation.

[0089] In other embodiments, the support base 420 may not extend outside the heat preservation furnace 100. In this case, the external drive mechanism can be connected to the support base 420 through a transmission component extending into the fourth segment 214 to realize power transmission and movement control. This application does not limit the installation form of the support base 420 and the external drive mechanism.

[0090] According to some embodiments of this application, please refer to Figures 3 to 5In the base 410 and the support 420, one is provided with a threaded post 431 and the other is provided with a mounting hole 432, and the threaded post 431 is threadedly engaged with the mounting hole 432.

[0091] The threaded post 431 refers to a columnar connection structure with external threads, and the mounting hole 432 refers to a hole-like structure with internal threads. The threaded post 431 and the mounting hole 432 mate to form a mating point to achieve precise positioning. High-strength mechanical fixation is achieved through rotation, which is compatible with the requirement of coaxial installation with the base 410 and the support 420.

[0092] For example, a threaded post 431 can be provided at the lower end of the base 410 and a mounting hole 432 can be provided at the upper end of the support 420; or a mounting hole 432 can be provided at the lower end of the base 410 and a threaded post 431 can be provided at the upper end of the support 420; this application does not limit this.

[0093] A standardized mechanical connection method is formed by setting threaded posts 431 on one of the base 410 or the support 420 and mounting holes 432 on the other. This connection method not only ensures the positional alignment between the base 410 and the support 420, but also achieves a high-strength fixing effect through the threaded engagement. In the high-temperature crystal 2003 growth environment, the self-locking characteristic of the threaded connection structure can prevent loosening or displacement of the connection. This stable connection structure can effectively maintain the stability of the crystal growth interface 520 and prevent crystal 2003 defects caused by the instability of the support platform.

[0094] According to some embodiments of this application, please refer to Figure 3 and Figure 4 The crystal growth apparatus 1000 also includes a temperature detection unit 600, which is located inside the holding furnace 100 and outside the crucible 200. The detection position of the temperature detection unit 600 is at the same height as the crystal growth interface 520, and the heater 300 responds to the temperature detection unit 600.

[0095] The temperature detection unit 600 is a device used to monitor temperature changes near the crystal growth interface 520 in real time. The temperature detection unit 600 can be a thermocouple, an infrared thermometer, or a fiber optic temperature sensor. The fact that the temperature detection unit 600 is located inside the holding furnace 100 and outside the crucible 200 means that it adopts a non-invasive layout to acquire temperature information, avoiding direct contact between the temperature detection unit 600 and the melt or crystal 2003, thus preventing contamination of the growth environment; at the same time, it protects the temperature detection unit 600 from corrosion by the high-temperature melt, thereby ensuring the stability and reliability of the monitoring process.

[0096] The temperature detection unit 600 is positioned at the same height as the crystal growth interface 520. Specifically, the detection point of the temperature detection unit 600 is precisely aligned with the precipitation region of the crystal 2003 in a direction perpendicular to gravity. This design effectively eliminates temperature monitoring delays or data errors caused by height deviations, ensuring that the temperature detection unit 600 collects real-time temperature information at the crystal growth interface 520, providing accurate data support for subsequent temperature control.

[0097] The heater 300 is designed to construct a complete closed-loop control circuit in response to the temperature detection unit 600. This closed-loop control circuit can be implemented through a closed-loop control circuit or a programmable logic controller (PLC). Based on the real-time data transmitted by the temperature detection unit 600, the closed-loop control circuit can dynamically adjust the heating power of the heater 300. When the temperature detection unit 600 detects that the temperature deviates from the preset value, the closed-loop control circuit will immediately compensate for heat loss or suppress heat accumulation, thereby maintaining a constant temperature at the crystal growth interface 520 and ensuring the thermodynamic stability of the crystal 2003 growth.

[0098] A complete closed-loop control system for real-time temperature monitoring and feedback is constructed by setting a temperature detection unit 600 inside the holding furnace 100. The temperature detection unit 600 is precisely deployed on the outside of the crucible 200, and its detection position height is precisely calibrated to be consistent with the crystal growth interface 520, enabling it to directly collect thermal radiation signals from the corresponding area and reflect the temperature state of the core area of ​​crystal 2003 precipitation in real time. Since the temperature of the crystal growth interface 520 directly determines the growth rate of crystal 2003 and the solid-liquid interface morphology, this precise alignment design makes the monitoring data highly targeted and effectively avoids temperature interference in non-critical areas. After the temperature detection unit 600 transmits the collected real-time temperature data to the control unit, the control unit generates adjustment commands based on preset temperature thresholds, driving the heater 300 to dynamically adjust its output power and accurately compensate for thermal field fluctuations caused by changes in the volume of the molten zone.

[0099] Furthermore, this design works synergistically with the segmented structure of the 210-supplied cavity, ensuring the basic stability of the thermal field from a structural perspective and actively suppressing thermal instability through closed-loop control. This effectively maintains the thermodynamic balance and solid-liquid interface morphology stability during the growth of crystal 2003, reduces the generation of micro-defects, and further improves the growth quality of crystal 2003.

[0100] In practical applications, the position of the crystal growth interface 520 and the initial position of the growth platform 400 are determined by the detection position of the temperature detection unit 600. Specifically, when the detection result of the temperature detection unit 600 is equal to the melting point of the crystal 2003 material, the portion of the horizontal plane at the same height as the detection position of the temperature detection unit 600 within the second segment 212 is the crystal growth interface 520. Correspondingly, when the heater 300 continuously heats and the detection result of the temperature detection unit 600 remains relatively stable, the upper surface of the molten zone is the melting interface 510.

[0101] To ensure that the upper end face of the molten zone is located in the first segment 211 and the lower end face is located in the second segment 212, the detection positions of the temperature detection unit 600 and the heater 300 can be defined. For example, the projection of the temperature detection unit 600 along the direction perpendicular to gravity is located in the second segment 212, the projection of the upper end face of the heater 300 along the direction perpendicular to gravity is located in the first segment 211, and the projection of the lower end face of the heater 300 along the direction perpendicular to gravity is located in the second segment 212. The extreme position of the lower end face of the heater 300 is flush with the upper end face of the second segment 212, but the extreme position of the upper end face of the heater 300 cannot be flush with the lower end face of the second segment 212; instead, it must maintain a certain distance from the lower end face of the second segment 212.

[0102] According to some embodiments of this application, please refer to Figure 3 and Figure 4 There is a gap between the temperature detection unit 600 and the outer peripheral surface of the crucible 200.

[0103] The gap between the temperature detection unit 600 and the outer peripheral surface of the crucible 200 refers to the physical distance between the temperature detection unit 600 and the outer peripheral surface of the crucible 200, and the temperature detection unit 600 does not directly contact the outer peripheral surface of the crucible 200.

[0104] By spacing the temperature detection unit 600 from the outer peripheral surface of the crucible 200, the temperature detection unit 600 avoids applying mechanical force to the crucible 200 through physical separation, preventing deformation or displacement of the crucible 200 due to contact pressure, and ensuring the structural stability of the crucible 200 in the high-temperature growth environment. At the same time, the non-contact gap setting can block direct heat conduction between the temperature detection unit 600 and the crucible 200, avoiding interference from the temperature of the temperature detection unit 600 itself by the heat conducted by the crucible 200, ensuring that the thermal radiation signal it collects only reflects the true temperature state of the crystal growth interface 520, and improving the accuracy of temperature monitoring data.

[0105] Furthermore, the gap between the temperature detection unit 600 and the crucible 200 can also reserve buffer space for the thermal expansion of the crucible 200 at high temperatures, avoiding collisions or compression between the temperature detection unit 600 and the crucible 200 during thermal expansion and contraction, further ensuring the safety and stability of the equipment operation.

[0106] According to some embodiments of this application, please refer to Figure 3 and Figure 4 The crystal growth apparatus 1000 also includes a heat shield 700, which is sleeved on the outer periphery of the crucible 200. The heat shield 700 has a mounting part 710 on the side facing the crucible 200, and the heater 300 is fixed to the mounting part 710.

[0107] The heat insulation cover 700 is a barrier structure with heat-blocking function, which can be made of graphite, ceramic, composite heat insulation material, ceramic fiber material, graphite composite material or metal-plated heat insulation plate, etc. The heat insulation cover 700 is fitted on the outer periphery of the crucible 200, which can effectively block the thermal interference of the internal environment of the holding furnace 100 to the crucible 200, significantly reduce the heat loss to the outside through radiation and convection, and create a stable heat preservation environment inside the crucible 200.

[0108] The mounting section 710 is a support and positioning structure located inside the heat insulation cover 700. It can be implemented using grooves, bosses, brackets, or slots. Its core purpose is to provide a precise positioning reference and a stable bearing point for the heater 300, ensuring a constant relative position between the heater 300 and the first section 211 molten material 2002, allowing for more concentrated and controllable heat input. This avoids potential heat conduction interference that might occur if the heater 300 were directly fixed to the crucible 200. The heater 300 is fixed to the mounting section 710 using mechanical connections such as bolts, clips, or welding, ensuring that it will not shift due to mechanical vibration or thermal expansion during crystal 2003 growth, thus guaranteeing the stability of the mounting position.

[0109] A physical heat insulation barrier is formed outside the crucible 200 by the heat insulation cover 700, reducing ineffective heat loss. Simultaneously, the mounting part 710 enables precise positioning and fixation of the heater 300. This dual approach maintains the temperature stability of the molten material 2002, providing strong support for the dynamic balance between the dissolution interface 510 and the crystal growth interface 520, effectively reducing microscopic defects caused by temperature fluctuations. This technical solution significantly improves the thermal field distribution during crystal 2003 growth, enabling more precise temperature control of the molten material 2002 and enhancing the stability of the solid-liquid interface. This reduces the probability of component segregation, interface bending, and internal defects in the crystal 2003, improving the integrity and compositional uniformity of the crystal 2003. Furthermore, this solution complements other structures in the crystal growth apparatus 1000, such as the heater 300, crucible 200, and receiving cavity 210, jointly ensuring the continuity and quality stability of crystal 2003 growth.

[0110] According to some embodiments of this application, please refer to Figure 3 and Figure 4 The receiving cavity 210 extends along the direction of gravity to the top of the crucible 200 and forms a first opening. The crystal growth apparatus 1000 includes a crucible plug 800, which covers the first opening.

[0111] The first opening is a channel structure formed at the top of the receiving cavity 210 in the direction of gravity. Its cross-section can be circular, elliptical, rectangular, or other forms. The first opening provides a convenient path for filling raw materials directly from the top during the loading process, conforming to the natural stacking characteristics of the raw materials and reducing the difficulty of operation.

[0112] The crucible plug 800 is a sealing component used to close the first opening. It can be made of graphite, ceramic, or metal composite materials, and its outer contour precisely matches the geometry of the first opening to achieve a tight seal. This sealing design can create a dynamic sealing barrier, which on the one hand prevents the intrusion of external impurities such as oxygen and moisture, thus avoiding contamination of the melt; on the other hand, it maintains the stability of the atmosphere and thermal field inside the holding furnace 100, reducing the interference of the external environment on the growth of crystal 2003.

[0113] The design of the receiving cavity 210 and the crucible plug 800 systematically solves the two core problems of material loading complexity and melt exposure. The structure of the receiving cavity 210 extending to the top of the crucible 200 eliminates the need to adapt to complex internal structures during the loading process. The material can be directly filled from top to bottom, which simplifies the operation process and reduces the probability of impurity introduction during loading, thereby improving the stability of the initial conditions for crystal 2003 growth. The sealing effect of the crucible plug 800 blocks the influence of adverse external factors from the source, ensuring the purity of the melt composition. At the same time, the sealing structure can maintain the dynamic balance of the thermal field and atmosphere inside the holding furnace 100, effectively reducing the volume fluctuation of the molten zone and the disturbance of the crystal growth interface 520, and significantly improving the continuity and quality uniformity of crystal 2003 growth.

[0114] In actual operation, during the loading stage, the operator can directly fill the raw material into the receiving cavity 210 through the first opening; after the loading is completed and before the crystal 2003 growth is started, the crucible plug 800 can be gently placed at the first opening to complete the seal, ensuring the stability of the growth environment inside the crucible 200. The operation is convenient and the seal is reliable.

[0115] This application also provides a crystal growth method, which is applied to the crystal growth apparatus described above. Please refer to... Figure 7 The crystal growth method specifically includes the following steps:

[0116] Step S10: Load the molten material and solid polycrystalline raw material into the receiving cavity;

[0117] Please refer to Figure 3 and Figure 4 During the loading process, the operator fills the raw materials from top to bottom through the first opening at the top of the crucible 200, following the natural accumulation characteristics of the raw materials and simplifying the operation process.

[0118] The molten material 2002 is initially filled from the lower part of the first section 211 to the upper end or upper part of the second section 212 of the receiving cavity 210. The solid polycrystalline raw material 2001 is stacked on top of the molten material 2002 in the first section 211, forming a stable upper and lower distribution structure of solid raw material-molten material 2002, which lays the foundation for subsequent dissolution and replenishment and crystal growth 2003.

[0119] After the material is loaded, the crucible plug 800 is placed over the first opening. The precise fit between the crucible plug 800 and the first opening achieves a seal, preventing the intrusion of external oxygen, moisture and other impurities, while maintaining the stability of the atmosphere inside the holding furnace 100.

[0120] Step S20: Heat the molten material in the heating zone using the heater;

[0121] Please refer to Figure 3 and Figure 4The heater 300 is precisely positioned by the mounting part 710 inside the heat insulation cover 700. Its heating area corresponds precisely to the height of the molten material 2002 in the receiving cavity 210, ensuring that the heat is concentrated on the molten material 2002 and avoiding energy waste.

[0122] During the heating process, the heat insulation cover 700 plays a role in heat insulation, reducing heat loss to the outside of the heat preservation furnace 100, and at the same time optimizing the uniformity of the heat field distribution inside the furnace.

[0123] The temperature detection unit 600 is deployed on the outside of the crucible 200. Its detection position is at the same height as the subsequently formed crystal growth interface 520, and a gap is reserved between it and the outer peripheral surface of the crucible 200. It collects the thermal radiation signal of the molten material 2002 in real time in a non-invasive manner. The temperature detection unit 600 transmits the real-time temperature data to the control unit. The control unit generates an adjustment command based on the preset temperature threshold, drives the heater 300 to dynamically adjust the output power, and forms a closed-loop control circuit to ensure that the temperature of the lower end face of the molten zone, i.e. the subsequent crystal growth interface 520, is stable within the preset range required for the growth of the crystal 2003, and avoids abnormal molten zone morphology due to temperature fluctuations.

[0124] After the heater 300 is started, it heats part of the outer periphery of the first section 211 of the crucible 200, keeping the molten material 2002 in the first section 211 in a molten state and forming a molten zone. As the heating process progresses, the molten zone extends upward to contact the solid polycrystalline raw material 2001 above, forming a stable dissolution interface 510. This dissolution interface 510 is always located in the first section 211 with a large cross section, ensuring the efficient dissolution of the solid raw material.

[0125] Step S30: Move the growth platform downward relative to the crucible, so that the solid polycrystalline raw material continuously dissolves into the molten zone material, while the substances in the molten zone material continuously precipitate on the growth platform to form crystals until crystal growth is completed.

[0126] Please refer to Figure 3 and Figure 4 The downward movement of the growth platform 400 is achieved through an external drive mechanism, such as a linear motor, a lead screw and nut, etc. During the downward movement, the solid raw material is dissolved and replenished and the crystal 2003 is precipitated and grown simultaneously until the growth of the target crystal 2003 is completed.

[0127] First, adjust the growth platform 400 to its initial position so that the lower end of the molten material 2002 contacts the seed crystal on the growth platform 400. When the temperature at the contact point between the seed crystal and the molten material 2002 is lower than the melting point of the crystal 2003 material, the solute in the molten material 2002 solidifies directionally on the surface of the seed crystal to form crystal 2003. The contact interface between the crystal 2003 and the molten material 2002 is defined as the crystal growth interface 520, which is always located within the second segment 212 of the small cross-section. Then, keep the power of the heater 300 stable while slowly sliding the growth platform downward. 400: On the one hand, the solid polycrystalline raw material 2001 in the first section 211 has a larger cross-sectional area and sufficient contact area with the molten zone. It continues to dissolve at the dissolution interface 510, dynamically replenishing the solute to the molten zone and making up for the melt consumption caused by the growth of crystal 2003. On the other hand, the solute in the molten zone material 2002 is transported to the bottom crystal growth interface 520 through diffusion or convection, continuously precipitating and causing crystal 2003 to grow layer by layer. Throughout the process, the molten zone remains in a fixed state until the solid polycrystalline raw material 2001 is completely dissolved, forming crystal 2003 of the target size.

[0128] Through the differentiated cross-sectional design of the accommodating cavity 210, it works in synergy with the raw material distribution in step S10 and the movement of the growth platform 400 in step S30: the large cross-section of the first section 211 expands the contact area between the solid polycrystalline raw material 2001 and the molten zone, significantly improving the dissolution rate; the small cross-section of the second section 212 makes the growth rate of the crystal growth interface 520 relatively controllable, achieving a dynamic balance between the "melt supply rate and the crystal 2003 consumption rate", avoiding the growth rate being limited due to insufficient feeding or the molten zone expansion caused by excessive feeding, thus ensuring growth efficiency and reducing defects such as component segregation and interface bending.

[0129] Furthermore, by adapting the aforementioned cross-sectionally differentiated cavity 210, the molten zone within the crucible 200 remains fixed, and continuous growth of the crystal 2003 is achieved through the moving growth platform 400. This design avoids dynamic instability of the molten zone volume caused by molten zone movement, improves the stability of the molten zone volume and the uniformity of the thermal field, thereby reducing interface bending and compositional segregation problems; while ensuring crystal growth efficiency, it also provides a guarantee for further optimization of the quality of the crystal 2003.

[0130] Furthermore, the "closed-loop temperature control formed by feedback adjustment between temperature detection unit 600 and heater 300" in step S20 is deeply adapted to the "fixed melting zone + moving platform" design in step S30. On the one hand, the closed-loop control accurately locks the temperature of the crystal growth interface 520, avoiding temperature fluctuations that cause instability in the melting zone morphology. On the other hand, the fixed melting zone design avoids the volume fluctuations caused by the traditional "moving melting zone". Combined with the heat insulation effect of the heat shield 700 and the non-contact heat conduction suppression of the growth platform 400, the heat field distribution in the furnace is more uniform, providing a stable thermodynamic environment for the ordered arrangement of crystal 2003 atoms, and further reducing microscopic defects such as dislocations and twins.

[0131] The above examples illustrate the principles and implementation methods of the present invention. These embodiments are merely illustrative and intended to aid in understanding the method and core concepts of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the present invention.

[0132] The following specific embodiments provide a detailed supplementary explanation of the contents of this application.

[0133] Example 1

[0134] This embodiment is used to prepare cadmium telluride (CdTe) crystals with a diameter of 30 mm.

[0135] Please see Figure 3 and Figure 4 Place the heat preservation furnace 100 on a platform, install the heater 300 at the mounting part 710 of the heat insulation cover 700, and then install the heater 300 and the heat insulation cover 700 together inside the heat preservation furnace 100, making sure that the heater 300 and the heat preservation furnace 100 are concentric.

[0136] The growth platform 400 is installed in the center of the bottom circular hole of the holding furnace 100. The crucible 200 is then slowly placed over the growth platform 400. The seed crystal is then slowly lowered from the top of the crucible 200 and finally lands on the top of the growth platform 400. The molten material 2002 is then placed on top of the seed crystal. Finally, the solid polycrystalline material 2001 is placed on top of the molten material 2002.

[0137] After all the raw materials have been placed, use crucible stopper 800 to seal the tail of crucible 200.

[0138] In this embodiment, when designing the size of the molten zone, the diameter of the crystal growth interface 520 at the bottom of the molten zone is designed to be 30 mm, and the diameter of the dissolution interface 510 is designed to be 60 mm. At this time, the area ratio of the dissolution interface 510 to the crystal growth interface 520 is 4:1. By referring to the phase diagram, the composition of the molten zone is designed so that the crystal melting point is 950℃. The heating program of the heater 300 is set so that the heater 300 heats up to 1000℃ after 24 hours. At this time, the reading of the temperature detection unit 600 is 962℃, indicating that the temperature at the seed crystal position has exceeded the designed crystal melting point temperature, and the seed crystal will partially melt, which meets the design requirements.

[0139] After the heater 300 is heated to a high temperature and held for 72 hours, the growth platform 400 is slowly lowered via a control program. During this time, the solid polycrystalline raw material 2001 above the molten material 2002 gradually melts, and the crystal growth interface 520 below gradually completes crystal growth. The crystal growth rate is equal to the descent rate of the growth platform 400. In this embodiment, the descent rate of the growth platform 400 is set to 3.2 mm / h. As the growth platform 400 descends to the desired position, the growth of the entire crystal 2003 is completed. It can be understood that the crystal 2003 includes a seed crystal and the portion grown on the surface of the seed crystal.

[0140] After crystal growth is complete, turn off the power to heater 300 to allow the entire system to cool down. Once the temperature reading from temperature detection unit 600 has dropped to room temperature, remove the grown crystal 2003.

[0141] Example 2

[0142] This embodiment is used to prepare cadmium zinc telluride (Cd0.96Zn0.04Te) crystals with a diameter of 50 mm.

[0143] Please see Figure 3 and Figure 4 Place the heat preservation furnace 100 on a platform, install the heater 300 at the mounting part 710 of the heat insulation cover 700, and then install the heater 300 and the heat insulation cover 700 together inside the heat preservation furnace 100, making sure that the heater 300 and the heat preservation furnace 100 are concentric.

[0144] The growth platform 400 is installed in the center of the bottom circular hole of the holding furnace 100. The crucible 200 is then slowly placed over the growth platform 400. The seed crystal is then slowly lowered from the top of the crucible 200 and finally lands on the top of the growth platform 400. The molten material 2002 is then placed on top of the seed crystal. Finally, the solid polycrystalline material 2001 is placed on top of the molten material 2002.

[0145] After all the raw materials have been placed, use crucible stopper 800 to seal the tail of crucible 200.

[0146] In this embodiment, when designing the size of the molten zone, the diameter of the crystal growth interface 520 at the bottom of the molten zone is designed to be 50 mm, and the diameter of the dissolution interface 510 is designed to be 111.8 mm. At this time, the area ratio of the dissolution interface 510 to the crystal growth interface 520 is 5:1. By referring to the phase diagram, the composition of the molten zone is designed so that the crystal melting point is 950℃. The heating program of the heater 300 is set so that the heater 300 heats up to 1000℃ after 24 hours. At this time, the reading of the temperature detection unit 600 is 962℃, indicating that the temperature at the seed crystal position has exceeded the designed crystal melting point temperature, and the seed crystal will partially melt, which meets the design requirements.

[0147] After the heater 300 is heated to a high temperature and held for 72 hours, the growth platform 400 is slowly lowered via a control program. During this time, the solid polycrystalline raw material 2001 above the molten material 2002 gradually melts, and the crystal growth interface 520 below gradually completes crystal growth. The crystal growth rate is equal to the descent rate of the growth platform 400. In this embodiment, the descent rate of the growth platform 400 is set to 2.8 mm / h. As the growth platform 400 descends to the desired position, the growth of the entire crystal 2003 is completed. It can be understood that the crystal includes the seed crystal and the portion grown on the surface of the seed crystal.

[0148] After crystal growth is complete, turn off the power to heater 300 to allow the entire system to cool down. Once the temperature reading from temperature detection unit 600 has dropped to room temperature, remove the grown crystal 2003.

[0149] Comparative Example 1

[0150] This comparative example was used to produce cadmium telluride (CdTe) crystals with a diameter of 30 mm. Compared with Example 1, there are no differences except for the shape of the crucible 200. The crucible 200 in the comparative example adopts the conventional equal-diameter crucible method, that is, the diameters of the crystal growth interface 520 and the dissolution interface 510 are equal.

[0151] Please see Figure 8 Place the heat preservation furnace 100 on a platform, install the heater 300 at the mounting part 710 of the heat insulation cover 700, and then install the heater 300 and the heat insulation cover 700 together inside the heat preservation furnace 100, making sure that the heater 300 and the heat preservation furnace 100 are concentric.

[0152] The growth platform 400 is installed in the center of the bottom circular hole of the holding furnace 100. The crucible 200 is then slowly placed over the growth platform 400. The seed crystal is then slowly lowered from the top of the crucible 200 and finally lands on the top of the growth platform 400. The molten material 2002 is then placed on top of the seed crystal. Finally, the solid polycrystalline material 2001 is placed on top of the molten material 2002.

[0153] After all the raw materials have been placed, use crucible stopper 800 to seal the tail of crucible 200.

[0154] In this embodiment, when designing the size of the molten zone, the diameter of the crystal growth interface 520 at the bottom of the molten zone is designed to be 30 mm, and the diameter of the dissolution interface 510 is also designed to be 30 mm. At this time, the area ratio of the dissolution interface 510 to the crystal growth interface 520 is 1:1. By referring to the phase diagram, the composition of the molten zone is designed so that the crystal melting point is 950℃. The heating program of the heater 300 is set so that the heater 300 heats up to 1000℃ after 24 hours. At this time, the reading of the temperature detection unit 600 is 962℃, indicating that the temperature at the seed crystal position has exceeded the designed crystal melting point temperature, and the seed crystal will partially melt, which meets the design requirements.

[0155] After the heater 300 is heated to a high temperature and held for 72 hours, the growth platform 400 is slowly lowered via a control program. During this time, the solid polycrystalline raw material 2001 above the molten material 2002 gradually melts, and the crystal growth interface 520 below gradually completes crystal growth. The crystal growth rate is equal to the descent rate of the growth platform 400. In this embodiment, the descent rate of the growth platform 400 is set to 0.8 mm / h. As the growth platform 400 descends to the desired position, the growth of the entire crystal 2003 is completed. It can be understood that the crystal 2003 includes a seed crystal and the portion grown on the surface of the seed crystal.

[0156] After crystal growth is complete, turn off the power to heater 300 to allow the entire system to cool down. Once the temperature has dropped to room temperature as detected by temperature detection unit 600, remove the grown crystal 2003.

[0157] Comparative Example 2

[0158] This comparative example was used to prepare cadmium zinc telluride (Cd0.96Zn0.04Te) crystals with a diameter of 50 mm. Compared with Example 2, there are no differences except for the shape of the crucible 200. The crucible 200 in the comparative example adopts the conventional equal-diameter crucible method, that is, the diameters of the crystal growth interface 520 and the dissolution interface 510 are equal.

[0159] Please see Figure 8 Place the heat preservation furnace 100 on a platform, install the heater 300 at the mounting part 710 of the heat insulation cover 700, and then install the heater 300 and the heat insulation cover 700 together inside the heat preservation furnace 100, making sure that the heater 300 and the heat preservation furnace 100 are concentric.

[0160] The growth platform 400 is installed in the center of the bottom circular hole of the holding furnace 100. The crucible 200 is then slowly placed over the growth platform 400. The seed crystal is then slowly lowered from the top of the crucible 200 and finally lands on the top of the growth platform 400. The molten material 2002 is then placed on top of the seed crystal. Finally, the solid polycrystalline material 2001 is placed on top of the molten material 2002.

[0161] After all the raw materials have been placed, use crucible stopper 800 to seal the tail of crucible 200.

[0162] In this embodiment, when designing the size of the molten zone, the diameter of the crystal growth interface 520 at the bottom of the molten zone is designed to be 30 mm, and the diameter of the dissolution interface 510 is also designed to be 50 mm. At this time, the area ratio of the dissolution interface 510 to the crystal growth interface 520 is 1:1. By referring to the phase diagram, the composition of the molten zone is designed so that the crystal melting point is 950℃. The heating program of the heater 300 is set so that the heater 300 heats up to 1000℃ after 24 hours. At this time, the reading of the temperature detection unit 600 is 962℃, indicating that the temperature at the seed crystal position has exceeded the designed crystal melting point temperature, and the seed crystal will partially melt, which meets the design requirements.

[0163] After the heater 300 is heated to a high temperature and held for 72 hours, the growth platform 400 is slowly lowered via a control program. During this time, the solid polycrystalline raw material 2001 above the molten material 2002 gradually melts, and the crystal growth interface 520 below gradually completes crystal growth. The crystal growth rate is equal to the descent rate of the growth platform 400. In this embodiment, the descent rate of the growth platform 400 is set to 0.7 mm / h. As the growth platform 400 descends to the desired position, the growth of the entire crystal 2003 is completed. It can be understood that the crystal 2003 includes a seed crystal and the portion grown on the surface of the seed crystal.

[0164] After crystal growth is complete, turn off the power to heater 300 to allow the entire system to cool down. Once the temperature reading from temperature detection unit 600 has dropped to room temperature, remove the grown crystal 2003.

[0165] To examine the effectiveness of this invention, the following experiments were conducted on the crystal growth results.

[0166] I. Results of crystal growth

[0167] After removing the crystals 2003 grown in Examples 1 and 2 and Comparative Examples 1 and 2, they were cut along the axial direction to produce wafers of the same thickness. The grain distribution on the cut surface was then examined, and the results are as follows: Figure 9 As shown. Among them, Figure 9 This is a cross-sectional view of the crystal prepared in Example 1 of this application. Figure 10 This is a cross-sectional view of the crystal prepared in Comparative Example 1 of this application. Figure 11This is a cross-sectional view of the crystal prepared in Example 2 of this application. Figure 12 This is a cross-sectional view of the crystal prepared in Comparative Example 1 of this application.

[0168] contrast Figure 9 and Figure 10 , Figure 11 and Figure 12 It can be seen that in Examples 1 and 2, the crystal 2003 grown in the molten zone underwent rapid solidification due to the shutdown and cooling process after crystal growth, resulting in polycrystalline formation in the molten zone, which is normal. The target crystal grown below exhibits a uniform color overall, with no grain boundaries or polycrystalline structures observed. In Comparative Examples 1 and 2, although some large grains were present in the crystal 2003, grain boundaries were also present, resulting in polycrystalline formation.

[0169] II. Comparison of Crystal Growth Efficiency

[0170] Using the method of this invention, the crystal growth rate is significantly higher than that of traditional crystal growth methods. The speed comparison is summarized in the table below:

[0171] Table 1. Comparison of crystal growth rates between the examples and comparative examples

[0172]

[0173] As can be seen from the grain results of Examples 1 and 2 and Comparative Examples 1 and 2, after adopting the method of the present invention, since the dissolution interface area is much larger than the crystal growth interface, it provides sufficient dissolution rate and solute transport is more sufficient. Therefore, the grains of the grown crystal 2003 are significantly better than those of the traditional crystal growth method.

[0174] The comparison of crystal growth speed shows that the crystal growth speed is significantly improved by using the asymmetric dissolution interface 510 and crystal growth interface 520, which can effectively improve crystal growth efficiency.

[0175] In summary, the crystal growth method of this invention can significantly improve the crystal growth rate and obtain large-size single crystals, with remarkable effects.

Claims

1. A crystal growth apparatus (1000), characterized in that, include: Insulation furnace (100); A crucible (200) is disposed inside the holding furnace (100). The interior of the crucible (200) has a receiving cavity (210) for receiving molten material (2002) and solid polycrystalline raw material (2001). The receiving cavity (210) includes a first section (211) and a second section (212) arranged along the direction of gravity. The first section (211) is located above the second section (212) and communicates with the second section (212). The cross-sectional area of ​​the first section (211) perpendicular to the direction of gravity is greater than the cross-sectional area of ​​the second section (212) perpendicular to the direction of gravity. The solid polycrystalline raw material (2001) contacts the molten material (2002) to form a dissolution interface (510). The dissolution interface (510) is located inside the first section (211). A heater (300) is disposed inside the heat preservation furnace (100) and located on the outer periphery of the first section (211). The heater (300) is used to heat the molten material (2002) located in the first section (211). A growth platform (400) is slidably connected to the crucible (200) along the direction of gravity and extends into the second section (212). The growth platform (400) is used to support the crystal (2003). The crystal (2003) contacts the molten material (2002) to form a crystal growth interface (520). The crystal growth interface (520) is located within the second section (212). The growth platform (400) is used to move the crystal (2003) supported on the growth platform (400) relative to the crucible (200) along the direction of gravity.

2. The crystal growth apparatus (1000) according to claim 1, characterized in that, The ratio of the cross-sectional area of ​​the first segment (211) perpendicular to the direction of gravity to the cross-sectional area of ​​the second segment (212) perpendicular to the direction of gravity is 1.5:1 to 10:

1.

3. The crystal growth apparatus (1000) according to claim 1, characterized in that, The receiving cavity (210) includes a third segment (213) along the direction of gravity, the third segment (213) being located between and connecting the first segment (211) and the second segment (212). The cross-sectional area of ​​the third segment (213) perpendicular to the direction of gravity gradually decreases along the direction from the first segment (211) to the second segment (212).

4. The crystal growth apparatus (1000) according to claim 1, characterized in that, The receiving cavity (210) includes a fourth segment (214) along the direction of gravity. The fourth segment (214) is located below the second segment (212). The cross-sectional area of ​​the fourth segment (214) perpendicular to the direction of gravity is greater than the cross-sectional area of ​​the second segment (212) perpendicular to the direction of gravity. The outer peripheral surface of the growth platform (400) slides in contact with the hole wall of the second segment (212), and there is a gap between the outer peripheral surface of the growth platform (400) and the hole wall of the fourth segment (214).

5. The crystal growth apparatus (1000) according to claim 1, characterized in that, The growth platform (400) includes a base (410) for supporting the crystal (2003), the base (410) being made of graphite.

6. The crystal growth apparatus (1000) according to claim 5, characterized in that, The growth platform (400) includes a support base (420), one end of the base (410) is connected to the support base (420), and the other end of the base (410) extends into the second section (212) and is used to support the crystal (2003). The support base (420) is made of ceramic material.

7. The crystal growth apparatus (1000) according to claim 6, characterized in that, Of the base (410) and the support (420), one is provided with a threaded post (431) and the other is provided with a mounting hole (432), and the threaded post (431) is threadedly engaged with the mounting hole (432).

8. The crystal growth apparatus (1000) according to any one of claims 1 to 7, characterized in that, The crystal growth apparatus (1000) further includes a temperature detection unit (600), which is located inside the holding furnace (100) and outside the crucible (200). The detection position of the temperature detection unit (600) is at the same height as the crystal growth interface (520), and the heater (300) responds to the temperature detection unit (600).

9. The crystal growth apparatus (1000) according to claim 8, characterized in that, There is a gap between the temperature detection unit (600) and the outer peripheral surface of the crucible (200).

10. The crystal growth apparatus (1000) according to any one of claims 1 to 7, characterized in that, The crystal growth apparatus (1000) also includes a heat shield (700), which is fitted around the outer periphery of the crucible (200). The heat shield (700) has a mounting part (710) on the side facing the crucible (200), and the heater (300) is fixed to the mounting part (710).

11. The crystal growth apparatus (1000) according to any one of claims 1 to 7, characterized in that, The receiving cavity extends along the direction of gravity to the top of the crucible (200) and forms a first opening. The crystal growth apparatus (1000) includes a crucible plug (800) which covers the first opening.

12. A crystal growth method, characterized in that, The crystal growth method is applied to the crystal growth apparatus according to any one of claims 1 to 11, and the crystal growth method comprises: The molten material and solid polycrystalline raw material are loaded into the receiving cavity; The molten material is heated by the heater. The growth platform is moved downward relative to the crucible, causing the solid polycrystalline raw material to continuously dissolve into the molten zone material. At the same time, the substances in the molten zone material continuously precipitate on the growth platform to form crystals until crystal growth is completed.

Images