Crystal growth device and method

Abstract

The embodiment of the invention provides a crystal growth device and method.The crystal growth device comprises a heat preservation furnace, a crucible, a heater and a growth platform, the crucible and the heater are both arranged in the heat preservation furnace, a containing cavity is formed in the crucible and comprises a first section and a second section which are arranged in the gravity direction and communicate with each other, and the first section is located above the second section; the heater is positioned on the peripheral side of the first section and is used for heating the melting zone material positioned on the first section; the solid polycrystalline raw material is in contact with the melting zone material to form a dissolving interface which is positioned in the first section; the growth platform is in sliding connection with the crucible in the gravity direction and extends into the second section, the growth platform is used for supporting crystals, the crystals make contact with the melting zone material to form a crystal growth interface, and the crystal growth interface is located in the second section; the cross-sectional area of the first section perpendicular to the gravity direction is larger than the cross-sectional area of the second section perpendicular to the gravity direction. According to the technical scheme provided by the invention, the crystal growth efficiency can be improved under the condition of guaranteeing the crystal quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of single crystal preparation, in particular to a crystal growth device and method. BACKGROUND

[0002] In the field of crystal growth, the cross-sectional area of the dissolution interface and the growth interface in the traditional device usually remains basically unchanged. This design causes the dissolution rate of the solid polycrystalline raw material to be unable to effectively match the consumption demand of the melt in the crystal growth process. When the growth rate is increased, the melt zone continues to shrink or even interrupts due to insufficient supply of raw materials, causing uneven supply of melt, instability of the solid-liquid interface and other phenomena. The interface instability further causes defects such as component segregation, interface bending and parasitic nucleation, which seriously affect the crystal quality. At the same time, the dynamic fluctuation of the volume of the melt zone destroys the stability of the thermal field distribution and the solute concentration, aggravates the accumulation of internal stress and the formation of micro defects in the crystal, and finally leads to the decline of the crystal integrity, the deterioration of the uniformity and the degradation of the electrical performance. SUMMARY

[0003] The embodiments of the present application provide a crystal growth device and method, which can improve the crystal growth efficiency while ensuring the crystal quality.

[0004] The present application is realized by the following technical solutions: In a first aspect, the embodiments of the present application provide a crystal growth device, which comprises a holding furnace, a crucible, a heater and a growth platform. The crucible is arranged in the holding furnace, and the interior of the crucible has a containing cavity. The containing cavity is used to contain a melt zone material and a solid polycrystalline raw material. The containing cavity comprises a first section and a second section arranged along the gravity direction. The first section is located above the second section and communicates with the second section. The cross-sectional area of the first section perpendicular to the gravity direction is greater than that of the second section. The solid polycrystalline raw material contacts the melt zone material to form a dissolution interface, and the dissolution interface is located in the first section. The heater is arranged in the holding furnace and located at the outer circumferential side of the first section. The heater is used to heat the melt zone material located in the first section. The growth platform is slidably connected with the crucible along the gravity direction and extends into the second section. The growth platform is used to support a crystal. The crystal contacts the melt zone material to form a growth interface, and the growth interface is located in the second section.

[0005] In the technical scheme of the embodiments of the present application, the first section area of the accommodating cavity is designed to be larger than the second section area, so as to effectively increase the dissolution interface area to improve the dissolution rate of the solid polycrystalline raw material, ensure sufficient melt supply and maintain the dynamic stability of the melt zone, thereby avoiding the generation of interface instability and related defects, and having the advantages of improving the dissolution rate of the solid polycrystalline raw material, maintaining the stability of the melt zone, reducing the crystal growth defects, improving the crystal quality, and the like. Moreover, the accommodating cavity with the above-mentioned section differentiation design, the heater is fixed in the present application to keep the melt zone in the crucible fixed, and the continuous growth of the crystal is realized by moving the growth platform. The dynamic instability of the melt zone volume caused by the movement of the heater is avoided, the stability and the thermal field uniformity of the melt zone volume are improved, and then the interface bending and the component segregation problems are reduced; while ensuring the crystal growth efficiency, the further optimization of the crystal quality is ensured.

[0006] According to the first aspect, in a possible implementation manner, a ratio of a section area of the first section perpendicular to the gravity direction to a section area of the second section perpendicular to the gravity direction is 1.5:1 to 10:1.

[0007] The lower limit of the ratio 1.5:1 can ensure that the dissolution interface area is significantly increased compared with the second section, and meet the basic dissolution efficiency requirement; the upper limit of the ratio 10:1 can avoid the excessive accumulation and flow loss of the melt caused by the too large section of the first section, while ensuring sufficient and uniform melt supply in the second section for crystal growth, effectively reducing the growth interruption caused by insufficient dissolution or the interface instability caused by excessive melt, and further improving the continuity and quality consistency of the crystal growth. In the crystal growth device, by limiting the ratio of the section area of the first section perpendicular to the gravity direction to the section area of the second section perpendicular to the gravity direction, the dissolution rate, the crystal growth speed and the stability of the melt zone are balanced.

[0008] According to the first aspect, in a possible implementation manner, the accommodating cavity comprises a third section, the third section is located between the first section and the second section and communicates the first section and the second section along the gravity direction; and a section area of the third section perpendicular to the gravity direction gradually decreases along a direction in which the first section points to the second section.

[0009] In the crystal growth device, the gradually changing section structure of the third section can guide the melt to flow smoothly from the large-section first section to the small-section second section, avoid the impact of vortex and turbulent flow caused by the sudden change of the section on the dissolution interface and the crystal growth interface, and maintain the stability of the melt zone shape; at the same time, the effective substances in the melt can be guided to the bottom along the gravity direction, which is beneficial to the full use of the effective substances in the solid polycrystalline raw material.

[0010] According to the first aspect, in a possible implementation manner, the accommodating cavity comprises a fourth section, the fourth section is located below the second section along the gravity direction, and a cross-sectional area of the fourth section perpendicular to the gravity direction is greater than a cross-sectional area of the second section perpendicular to the gravity direction; an outer circumferential surface of the growth platform is in sliding fit with a hole wall surface of the second section, and a gap exists between the outer circumferential surface of the growth platform and a hole wall surface of the fourth section.

[0011] In the crystal growth device, the growth platform is in sliding fit with the hole wall of the second section, the radial displacement of the growth platform is limited, the growth platform is stably lifted along the gravity direction, and the crystal is prevented from being eccentric or tilted; the gap of the fourth section can reduce the contact area of the growth platform and the crucible, thereby reducing heat loss and friction resistance when the growth platform is lifted.

[0012] According to the first aspect, in a possible implementation manner, the growth platform comprises a bottom support for supporting the crystal, and the bottom support is made of graphite.

[0013] By selecting the bottom support made of graphite, the high-temperature working condition of crystal growth is adapted, the risk of introducing impurities is reduced, and the purity of the crystal is ensured; and the bottom support made of graphite has good thermal conductivity, and can conduct away excess heat at the crystal growth interface to adjust the temperature gradient.

[0014] According to the first aspect, in a possible implementation manner, the growth platform comprises a support seat, one end of the bottom support is connected to the support seat, and the other end of the bottom support extends into the second section and is used for supporting the crystal; and the support seat is made of ceramic.

[0015] The support seat made of ceramic can provide rigid support in a temperature sensing environment, improve the structural stability, and the thermal conductivity coefficient of ceramic is much smaller than that of graphite, so that heat loss of the crystal growth area through the support seat can be reduced, and the thermal field in the crucible is maintained stable.

[0016] According to the first aspect, in a possible implementation manner, one of the bottom support and the support seat is provided with a threaded column, and the other is provided with a mounting hole; and the threaded column is in threaded fit with the mounting hole.

[0017] The threaded fit realizes quick disassembly and assembly of the bottom support and the support seat, facilitates timely replacement of the bottom support, and the threaded fit can ensure the connection strength and position accuracy of the bottom support and the support seat.

[0018] According to the first aspect, in a possible implementation manner, the crystal growth device further comprises a temperature detection unit, the temperature detection unit is located in the heat preservation furnace and outside the crucible, a detection position of the temperature detection unit is at the same height as the crystal growth interface, and the heater is responsive to the temperature detection unit.

[0019] 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 the power according to the detection signal, so that the crystal growth interface temperature is stabilized in the optimal interval, and the dislocation, cracks and component segregation caused by temperature fluctuation are reduced; the 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 the production efficiency.

[0020] According to the first aspect, in a possible implementation, the temperature detection unit and the outer circumferential surface of the crucible have a gap therebetween.

[0021] The gap between the temperature detection unit and the crucible can block the direct heat conduction path between the detection unit and the crucible wall, avoid the interference of the crucible wall temperature itself on the radiation temperature detection of the crystal growth interface, ensure that the detection value accurately reflects the real temperature of the crystal growth area, provide a reliable basis for the dynamic power adjustment of the heater, and indirectly ensure the stability of the melting zone temperature. And through non-contact arrangement, the stress of the external structure acting on the crucible is reduced, the contact friction or extrusion stress caused by equipment vibration and thermal expansion and contraction of the crucible is avoided, and the risk of micro-cracks and deformation of the crucible due to the action of external structures is reduced. The stability of the crucible structure can further ensure the integrity of the containment cavity shape and maintain the dynamic balance of the melting zone.

[0022] According to the first aspect, in a possible implementation, the crystal growth device further comprises a heat shield, the heat shield is sleeved on the outer circumferential side of the crucible, one side of the heat shield facing the crucible is provided with a mounting portion, and the heater is fixed to the mounting portion.

[0023] The heat shield can block the heat loss of the crucible to the outside, reduce heat loss and temperature fluctuation, maintain a stable thermal field, and reduce the energy consumption of the heater; the mounting portion provides a rigid fixing point for the heater, ensures that the heater is always aligned with the first outer circumferential side, and meets the core design of maintaining the stability of the melting zone by fixing the heater, thereby avoiding the displacement of the melting zone caused by the displacement of the heater; at the same time, the heat radiation of the heater to the outside is reduced, the heating efficiency is improved, and the service life of the heater is prolonged.

[0024] According to the first aspect, in a possible implementation, the containment cavity extends to the top end of the crucible along the gravity direction and forms a first opening, and the crystal growth device comprises a crucible plug, and the crucible plug covers the first opening.

[0025] The top opening facilitates direct filling of solid polycrystalline raw materials and a melting zone material, simplifies the operation process, and improves the filling efficiency; after the crucible plug is sealed, heat loss at the top can be reduced, the first-stage temperature reduction affecting the dissolution rate can be avoided, external air can be isolated, the melt and the crystal can be prevented from being oxidized, and the purity of the crystal can be ensured; the sealing structure reduces the loss of raw materials due to high-temperature volatilization, improves the utilization rate of raw materials, avoids pollution of equipment by volatilization, maintains a stable air pressure in the crucible, avoids airflow disturbance to the dissolution interface and the crystal growth interface, and reduces the defect rate.

[0026] In a second aspect, the embodiments of the present application provide a crystal growth method applied to the crystal growth device of the first aspect, and the crystal growth method comprises the following steps: Filling the melting zone material and the solid polycrystalline raw material into the containing cavity; Heating the melting zone material by the heater; Moving the growth platform downward relative to the crucible, so that the solid polycrystalline raw material is continuously dissolved into the melting zone material, and substances in the melting zone material continuously precipitate on the growth platform to form a crystal, until the crystal growth is completed.

[0027] In the technical solution of the embodiments of the present application, through the differentiated cross-section design of the device containing cavity, the raw material distribution in the crystal growth method and the movement of the growth platform form a synergy: the first-stage large cross-section enlarges the contact area of the solid polycrystalline raw material and the melting zone, significantly improving the dissolution rate; the second-stage small cross-section makes the growth rate of the crystal growth interface relatively controllable, realizes the dynamic balance of the “melt replenishment rate-crystal consumption rate”, avoids the growth rate being limited due to insufficient replenishment, or the melting zone being expanded due to excessive replenishment, and guarantees the growth efficiency and reduces defects such as component segregation and interface bending. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0029] Figure 1 A structure schematic diagram of a filling material in a crystal growth device provided by some embodiments of the present application; Figure 2 A structure schematic diagram of a crystal growth device provided by some embodiments of the present application; Figure 3 A structure schematic diagram of a filling material in a crystal growth device provided by some other embodiments of the present application; Figure 4A schematic diagram of the cooperation structure of the crucible and the growth platform provided for some embodiments of the present application; Figure 5 A schematic diagram of the cooperation structure of the crucible and the growth platform provided for some embodiments of the present application; Figure 6 A schematic diagram of the disassembly structure of the growth platform provided for some embodiments of the present application; Figure 7 A schematic diagram of the process of the crystal growth method provided for some embodiments of the present application; Figure 8 A schematic diagram of the structure of the crystal growth device provided for Comparative Examples 1 and 2 of the present application; Figure 9 A section view of the crystal prepared in Example 1 of the present application; Figure 10 A section view of the crystal prepared in Comparative Example 1 of the present application; Figure 11 A section view of the crystal prepared in Example 2 of the present application; Figure 12 A section view of the crystal prepared in Comparative Example 2 of the present application.

[0030] Reference signs: 1000 - crystal growth device; 100 - holding furnace; 200 - crucible; 210 - containing cavity; 211 - first section; 212 - second section; 213 - third section; 214 - fourth section; 300 - heater; 400 - growth platform; 410 - bottom support; 420 - support seat; 431 - threaded column; 432 - mounting hole; 510 - dissolving interface; 520 - crystal growth interface; 600 - temperature detection unit; 700 - heat shield; 710 - mounting part; 800 - crucible plug; 2001 - solid polycrystalline raw material; 2002 - melting zone material; 2003 - crystal. DETAILED DESCRIPTION

[0031] In order to make the present application clearer, specific embodiments will be described below with reference to the accompanying drawings: Please refer to Figure 1 and Figure 2The crystal growth device 1000 includes a furnace 100, a crucible 200, a heater 300, and a growth platform 400. The crucible 200 is arranged in the furnace 100, and has an accommodation cavity 210 in the interior thereof. The accommodation cavity 210 is used to accommodate a molten zone material 2002 and a solid polycrystalline raw material 2001. The accommodation cavity 210 includes a first section 211 and a second section 212 arranged along a gravity direction. The first section 211 is located above the second section 212 and is in communication with the second section 212. A cross-sectional area of the first section 211 perpendicular to the gravity direction is greater than a cross-sectional area of the second section 212 perpendicular to the gravity direction. The solid polycrystalline raw material 2001 is in contact with the molten zone material 2002 to form a dissolution interface 510, and the dissolution interface 510 is located in the first section 211. The heater 300 is arranged in the furnace 100 and is located at an outer circumferential side of the first section 211. The heater 300 is used to heat the molten zone material 2002 located in the first section 211. The growth platform 400 is slidably connected to the crucible 200 along the gravity direction and extends into the second section 212. The growth platform 400 is used to support a crystal 2003. The crystal 2003 is in contact with the molten zone material 2002 to form a crystal growth interface 520, and the crystal growth interface 520 is located in the second section 212.

[0032] The furnace 100 has an outer containment structure, provides installation space for internal components, maintains a stable temperature environment in the furnace, reduces heat loss, and avoids temperature fluctuations affecting the state of the molten zone material 2002 and the growth quality of the crystal 2003. The furnace 100 can adopt a multi-layer insulation design, such as graphite felt, ceramic fiber, etc. The furnace 100 is sealed, and inert protective gas, such as nitrogen, argon, etc., can be introduced into the furnace 100 to prevent oxidation or volatilization of the raw materials.

[0033] The crucible 200 has the accommodation 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 accommodation cavity 210 can be understood as a spatial structure for accommodating the molten zone material 2002 and the solid polycrystalline raw material 2001. The first section 211 and the second section 212 are located above the second section 212 and are in communication with the second section 212, which means that the lower end of the first section 211 and the upper end of the second section 212 are connected to form a stepped direct communication structure, or a tapered transition section is used to connect the lower end of the first section 211 and the upper end of the second section 212. The cross-sectional area of the first section 211 perpendicular to the gravity direction is greater than the cross-sectional area of the second section 212 perpendicular to the gravity direction, which is achieved by designing the accommodation cavity 210 as a combination of different geometric cavity sections, such as a stepped structure with a larger diameter upper cylinder and a smaller diameter lower cylinder, or a straight cylinder structure with a rectangular cross-section upper section and a smaller rectangular cross-section lower section. Of course, the cross-sectional shape of the first section 211 and the second section 212 perpendicular to the gravity direction can be other regular or irregular geometric shapes, which are not limited in the present application.

[0034] The heater 300 is located at the outer circumferential side of the first section 211, which does not mean that the heater 300 can completely cover the first section 211 along the direction of gravity, but means that the heater 300 and the first section 211 have a section of overlap along the first direction. The heater 300 can be understood as a device for providing heat energy, and the heater 300 can be wound by a resistance wire or use an inductive heating method to heat the melt zone material 2002. Specifically, the position and power of the heater 300 can be adjusted according to actual needs to ensure that the melt zone material 2002 can obtain uniform heat distribution.

[0035] The dissolution interface 510 is located in the first section 211, which means that the contact interface between the solid polycrystalline raw material 2001 and the melt zone material 2002 is limited within the first section 211, which ensures 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 in the second section 212, which means that the contact interface between the crystal 2003 and the melt zone material 2002 is arranged in the second section 212 region, in order to grow the crystal 2003 in a smaller cross-sectional area to maintain the shape stability of the solid-liquid interface.

[0036] The growth platform 400 is slidably connected to the crucible 200 along the direction of gravity, which means that the growth platform 400 can move relative to the crucible 200 along the direction of gravity, that is, the growth platform 400 can be moved up and down in the direction of gravity in the Figure 1 and Figure 2 to dynamically adjust the position of the growth platform 400 during the growth of the crystal 2003.

[0037] In the technical scheme of the embodiment of the present application, the solid polycrystalline raw material 2001 and the melting zone material 2002 are placed in the crucible 200 containing cavity 210, the solid polycrystalline raw material 2001 is located at the upper part of the first section 211, the melting zone material 2002 is located at the lower part of the first section 211 and the upper part of the second section 212, the top end of the growth platform 400 can be provided with a seed crystal and a start-up heater 300, the part of the outer periphery of the first section 211 of the crucible 200 is heated, so that the melting zone material 2002 in the first section 211 is kept in a molten state to form a melting zone, the melting 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 is continuously dissolved to form a melting zone. Adjust the movement of the growth platform 400 to the initial position, the lower end of the melting zone material 2002 contacts the seed crystal on the growth platform 400, when the temperature at the contact position of the seed crystal and the melting zone material 2002 is lower than the melting point of the crystal material, the solute in the melting zone material 2002 directionally solidifies on the growth platform 400 to generate a crystal 2003, the contact interface of the crystal 2003 and the melting zone material 2002 is defined as a crystal growth interface 520, and the crystal growth interface 520 is located in the second section 212. Keep the power of the heater 300 stable, and slowly slide the growth platform 400 downward in the process, in this process, the solid polycrystalline raw material 2001 continuously dissolves at the dissolution interface 510 to supplement the solute in the melting zone material 2002, the solute in the melting zone material 2002 is transported to the bottom through diffusion or convection of the melting zone material 2002, and is precipitated at the crystal growth interface 520, so that the crystal 2003 grows layer by layer until the crystal 2003 of the target size is formed.

[0038] In the technical scheme of the embodiment of the present application, the solid polycrystalline raw material 2001 and the melting zone material 2002 are placed in the crucible 200 containing cavity 210, the solid polycrystalline raw material 2001 is located at the upper part of the first section 211, the melting zone material 2002 is located at the lower part of the first section 211 and the upper part of the second section 212, the top end of the growth platform 400 can be provided with a seed crystal and a start-up heater 300, the part of the outer periphery of the first section 211 of the crucible 200 is heated, so that the melting zone material 2002 in the first section 211 is kept in a molten state to form a melting zone, the melting 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 is continuously dissolved to form a melting zone.

[0039] In addition, the accommodating cavity 210 is adapted to the cross-section differentiation design, the heater 300 is fixed in position in the application, thereby keeping the melt zone in the crucible 200 fixed, and the continuous growth of the crystal 2003 is realized by moving the growth platform 400. The design avoids the dynamic instability of the melt zone volume caused by the movement of the heater 300, improves the stability and thermal field uniformity of the melt zone volume, and further reduces the interface bending and component segregation problems; while ensuring the crystal growth efficiency, the design provides a guarantee for the further optimization of the quality of the crystal 2003.

[0040] According to some embodiments of the application, please refer to Figure 1 and Figure 2 The ratio of the cross-sectional area of the first section 211 perpendicular to the direction of gravity to the cross-sectional area of the second section 212 perpendicular to the direction of gravity is 1.5:1 to 10:1.

[0041] The cross-sectional area ratio refers to the ratio of the cross-sectional area of the first section 211 perpendicular to the direction of gravity to the cross-sectional area of the second section 212 perpendicular to the direction of gravity, which 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 expanding the difference between the dissolution interface 510 area and the crystal growth interface 520 area, the dissolution rate of the solid polycrystalline raw material 2001 can efficiently match the consumption demand of the melt zone material 2002, laying a foundation for the improvement of the crystal growth efficiency and quality.

[0042] In the case where the cross-sectional area ratio of the first section 211 to the second section 212 is 1.5:1, taking the inner diameter of the second section 212 as φ30mm as an example, the cross-sectional area of the second section 212 is about 707mm², and the cross-sectional area of the first section 211 is about 1060mm². Under this condition, the dissolution interface 510 area is increased by about 50% compared with the traditional straight cylinder type crucible; experimental data shows that under the conditions of stable heating power and high-purity argon protective atmosphere, the growth platform 400 can support a downward movement speed of 0.8-1.2mm / h; considering the solidification shrinkage and interface dynamic balance, the actual crystal growth speed is 0.7-1.1mm / h; compared with the traditional straight cylinder type zone melting method device, under the premise of the same crystal growth interface 520 area, due to the limited dissolution capacity, the maximum stable crystal growth speed is usually not more than 0.5mm / h; the application scheme makes the crystal growth speed increase by about 40% to 120%, significantly improving the production efficiency.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] According to some embodiments of this application, please refer to Figure 3 and Figure 4The accommodating cavity 210 comprises a third section 213, which is located between the first section 211 and the second section 212 and communicates the first section 211 and the second section 212 along the direction of gravity, and the cross-sectional area of the third section 213 perpendicular to the direction of gravity gradually decreases along the direction from the first section 211 to the second section 212.

[0048] The third section 213 refers to the part of the accommodating cavity 210 as a transition region, which is located between the first section 211 and the second section 212 and communicates the first section 211 and the second section 212. It can be understood that this region ensures that the melt must flow through this transition section, avoiding the interruption of the flow path. The cross-sectional area of the third section 213 perpendicular to the direction of gravity gradually decreases along the direction from the first section 211 to the second section 212, which means that the cross-sectional area continuously decreases, which can be in the form of linear tapering or nonlinear tapering. The third section 213 can specifically adopt a conical structure or a parabolic tapering structure with smooth cross-sectional changes to realize the cross-sectional area, which converts the sudden change of the cross-sectional area into continuous change, optimizes the solute transfer path, and avoids the sudden increase of flow rate or turbulence phenomenon of the melt during the flow process due to the sudden change of the cross-sectional area. And avoid the deposition of solute at the sudden change of cross-sectional area, improve the utilization rate of solid polycrystalline raw material 2001 effective matter.

[0049] By connecting the first section 211 and the second section 212 through the third section 213, when the melt flows from the first section 211 with a large cross-sectional area to the second section 212 with a small cross-sectional area under the driving of gravity, the continuous change of the cross-sectional area promotes the smooth transition of the flow rate, avoiding the sudden change of the flow rate and the loss of kinetic energy caused by the sudden change of the cross-sectional area, thereby maintaining the uniformity of the thermal field distribution and the stability of the solute concentration, and ensuring the stability of the shape of the dissolution interface 510 and the crystal growth interface 520.

[0050] Please refer to Figure 4 and Figure 5 The third section 213 can be specifically designed as a conical transition section with a smooth inner wall, and the inner surface of the third section 213 is a continuous curved surface to realize the smooth transition of the melt flow.

[0051] In the case that the accommodating cavity 210 has the first section 211, the second section 212 and the third section 213, the height of the upper end of the heater 300 is located in the interval of the first section 211, 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 interval of the second end, that is, along the direction of gravity, the heater 300 overlaps part of the first section 211 and all of the third section 213, and the heating can partially overlap the second section 212, so that in the case that the heater 300 is started, a melting zone composed 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 accommodating cavity 210.

[0052] In other embodiments, the first section 211 and the second section 212 can also be directly communicated, which is not limited in the application.

[0053] According to some embodiments of the application, please refer to Figure 3 and Figure 4 The accommodation cavity 210 includes a fourth section 214, which is located below the second section 212 in the direction of gravity, and the cross-sectional area of the fourth section 214 perpendicular to the direction of gravity is greater than that of the second section 212. The outer circumferential surface of the growth platform 400 is in sliding fit with the hole wall surface of the second section 212, and there is a gap between the outer circumferential surface of the growth platform 400 and the hole wall surface of the fourth section 214.

[0054] The fourth section 214 refers to a specific area added in the structure of the accommodation cavity 210, which can be realized by a cavity structure with a gradually changing cross-sectional area. The change in cross-sectional area can be realized by taper transition or stepped expansion, etc.

[0055] The sliding fit between the outer circumferential surface of the growth platform 400 and the hole wall surface of the second section 212 means that they are axially connected by close fit. For example, the fitting gap between the outer circumferential surface of the growth platform 400 and the hole wall surface of the second section 212 can be 0.05mm to 0.1m, which can be realized by high-precision machined fitting surfaces to avoid the flow of the melt zone material 2002 from the growth platform 400 and the hole wall surface of the second section 212 to the fourth section 214; the growth platform 400 and the hole wall surface of the second section 212 have a certain fitting height to ensure that the crystal 2003 is stably supported in the second section 212 and the growth interface 520 is maintained flat.

[0056] It should be noted that during the growth of the crystal 2003, the growth platform 400 moves downward while maintaining close contact with the inner wall of the hole of the second section 212.

[0057] The gap between the outer circumferential surface of the growth platform 400 and the hole wall surface of the fourth section 214 refers to the annular gap reserved, and the fitting gap between the outer circumferential surface of the growth platform 400 and the hole wall surface of the fourth section 214 is greater than or equal to 1mm; that is, the growth platform 400 does not directly contact the inner wall of the hole of the fourth section 214.

[0058] By designing the accommodating cavity 210 of the crucible 200 to have the second section 212 closely fit the growth platform 400 and the fourth section 214 have a gap reserved for the growth platform 400, on the one hand, the high-precision sliding fit between the second section 212 and the growth platform 400 builds a sealed barrier in the region where the melt zone is located, completely avoids the leakage of the melt zone material 2002 downward to the fourth section 214, ensures the stability of the volume of the melt zone, reduces the waste of raw materials, and effectively avoids the growth defects of the crystal 2003 such as inclusions and uneven composition; and the continuous close fit between the growth platform 400 and the hole wall of the second section 212 can reduce the heat loss at the fitting interface, limit the lateral heat diffusion range of the melt zone, ensure the uniformity and stability of the temperature gradient at the crystal growth interface 520, and provide a good thermodynamic environment for the ordered arrangement of atoms of the crystal 2003, thereby significantly reducing the probability of defects such as dislocations and twins of the crystal 2003. On the other hand, the large cross-section design of the fourth section 214 forms an annular gap, so that the growth platform 400 only contacts the hole wall of the second section 212 during the downward movement of the growth platform 400, which greatly reduces the contact area between the growth platform 400 and the crucible 200, reduces the axial sliding resistance, avoids the growth interruption or interface disturbance caused by mechanical jamming, ensures the continuity and stability of the crystal 2003 growth process, reduces the heat conduction path through the wall of the crucible 200, reduces the ineffective heat conduction of the melt zone to the low-temperature region, saves energy, and avoids the composition segregation of the crystal 2003 caused by temperature fluctuations.

[0059] In addition, the stable support of the second section 212 to the growth platform 400 and the design of the fitting height can effectively limit the disordered expansion of the radial growth of the crystal 2003, help maintain the preset size of the crystal 2003, and significantly improve the yield and size accuracy of the crystal 2003, thereby providing comprehensive protection for the stability of the crystal 2003 growth and the improvement of the quality of the crystal 2003 from the structural level.

[0060] According to some embodiments of the present application, please refer to Figure 3 , Figure 4 and Figure 6 , the growth platform 400 includes a bottom support 410 for supporting the crystal 2003, and the bottom support 410 is made of graphite.

[0061] The bottom support 410 as the core support component directly contacting the crystal 2003 in the growth platform 400 can be made of graphite. Graphite has excellent extreme high-temperature structural stability and chemical inertness: in the high-temperature environment of the crystal 2003 growth, it can effectively resist deformation caused by thermal stress, ensure the stability of the support structure, and avoid adverse reactions with the molten material, thereby avoiding pollution risks from the contact interface level. In practical applications, the bottom support 410 can keep the crystal growth interface 520 fixed in position during the entire growth process, while achieving uniform heat conduction, thereby reducing the adverse effects of local temperature fluctuations on the ordered growth of the crystal 2003.

[0062] The graphite material includes various types such as molded graphite, baked graphite, isostatic graphite, etc. The specific preparation process of the graphite is not specially limited in the present application, and can be flexibly selected according to the actual needs of the crystal 2003 growth.

[0063] The base support 410 is designed to be of graphite material, which can fully exert the advantages of the material properties. On the one hand, the excellent high thermal conductivity of graphite can make the heat quickly and uniformly conduct and distribute on the surface of the base support 410, effectively inhibit the generation of local temperature gradient, and avoid the defects of the crystal 2003 caused by interface fluctuation. On the other hand, the chemical inertness of graphite in a high temperature environment can block the potential reaction path with the molten polycrystalline raw material, thereby eliminating the risk of impurity pollution from the source.

[0064] In some embodiments, the base support 410 is processed into a disc structure by using high-purity graphite, and the surface thereof in contact with the crystal 2003 is finely polished. The base support 410 is directly integrated into the support structure of the growth platform 400, which ensures the support strength and installation stability, and further improves the reliability of the crystal 2003 growth process.

[0065] According to some embodiments of the present application, please refer to Figure 3 and Figure 4 The growth platform 400 includes a support seat 420, one end of the base support 410 is connected with the support seat 420, and the other end of the base support 410 extends into the second section 212 and is used to support the crystal 2003. The support seat 420 is of ceramic material.

[0066] The support seat 420 is a core structural support component of the growth platform 400, and bears the main mechanical bearing function. The support seat 420 is made of ceramic material, which has excellent high-temperature stability and structural rigidity. Specifically, alumina ceramic, silicon nitride ceramic or silicon carbide ceramic materials can be used. The ceramic material support seat 420 can provide a stable rigid frame for the growth platform 400, effectively resist the bending and deformation caused by the accumulation of thermal stress during the growth of the crystal 2003, and ensure the dimensional stability of the overall structure.

[0067] The connection mode of the base support 410 and the support seat 420 can adopt mechanical fixation or chemical bonding structure, including buckle cooperation, mortise and tenon connection or high-temperature adhesive bonding, etc. The connection structure needs to meet the firm constraint requirement in a high temperature environment, so as to ensure that the graphite base support 410 does not deviate in the dynamic process of the crystal 2003 growth, effectively resist the influence of external forces such as melt buoyancy and equipment vibration, and ensure the position stability of the crystal growth interface 520.

[0068] The support seat 420 made of ceramic material cooperates with the bottom support 410 made of graphite material. The difference in the thermal expansion coefficients of the two materials is buffered by the flexible design of the connecting structure, allowing a small relative displacement during thermal expansion, thereby absorbing the thermal stress caused by temperature changes and avoiding damage such as deformation and cracking of the bottom support 410. At the same time, the design of the bottom support 410 extending into the second section 212 to support the crystal 2003 can take advantage of the high thermal conductivity of graphite to achieve uniform heat transfer from the growth area to the support seat 420, maintaining the stability of the thermal field at the growth interface 520. The rigid support of the ceramic support seat 420 can ensure the positional accuracy of the growth platform 400 during axial sliding, avoiding interface disturbance caused by vibration or displacement, and balancing the need for heat conduction and structural stability to create a stable thermodynamic environment for crystal 2003 growth.

[0069] In actual applications, the bottom support 410 and the support seat 420 can both be designed as columnar structures, and are coaxially arranged to ensure uniform stress and accurate positioning. In addition, the bottom support 410 can also be in the form of a graphite coating arranged on the upper end surface of the support seat 420, and the specific structural form of the support seat 420 is not limited in the present application.

[0070] Furthermore, the end of the support seat 420 away from the bottom support 410 can extend to the outside of the holding furnace 100 and be connected to an external driving mechanism. The specific form of the external driving mechanism is not limited in the present application, for example, a linear motor can be used for direct driving, a rotary motor can be used in combination with a gear and rack for driving, or a rotary motor can be used in combination with a screw and nut for driving, as long as the bidirectional stable movement of the support seat 420 can be achieved, i.e., downward driving to complete crystal 2003 growth and upward resetting to the initial position to meet the use requirements.

[0071] Based on the above embodiment, the end of the support seat 420 away from the bottom support 410 is provided with a radially outwardly extending stopper. When the support seat 420 moves upward for resetting, the stopper can form a limiting cooperation with the outer wall surface of the holding furnace 100, mechanically abutting to limit the maximum upward stroke of the support seat 420, avoiding the support seat 420 from completely entering the accommodating cavity 210, and ensuring the safety and structural rationality of the equipment operation.

[0072] In other embodiments, the support seat 420 can also not extend to the outside of the holding furnace 100. In this case, the external driving mechanism can be connected to the support seat 420 through a transmission component extending into the fourth section 214 to achieve power transmission and movement control, and the mounting form of the support seat 420 and the external driving mechanism is not limited in the present application.

[0073] According to some embodiments of the present application, please refer to Figure 3 to Figure 5One of the bottom support 410 and the support base 420 is provided with a threaded column 431, and the other is provided with a mounting hole 432, and the threaded column 431 is threadedly matched with the mounting hole 432.

[0074] The threaded column 431 refers to a columnar connecting structure with external threads, and the mounting hole 432 refers to a hole-shaped structure with internal threads, and the threaded column 431 and the mounting hole 432 are matched to form a butt joint point to achieve accurate position alignment. High-strength mechanical fixation is achieved by rotation, which is adapted to the requirement of coaxial installation of the bottom support 410 and the support base 420.

[0075] For example, the threaded column 431 can be arranged at the lower end of the bottom support 410, and the mounting hole 432 can be arranged at the upper end of the support base 420; or the mounting hole 432 can be arranged at the lower end of the bottom support 410, and the threaded column 431 can be arranged at the upper end of the support base 420; the present application does not limit this.

[0076] By arranging the threaded column 431 on one of the bottom support 410 or the support base 420 and arranging the mounting hole 432 on the other, a standardized mechanical connection mode is formed. This connection mode not only ensures the position alignment between the bottom support 410 and the support base 420, but also achieves a high-strength fixing effect through thread matching. In the high-temperature crystal 2003 growth environment, the self-locking property of the threaded connection structure can avoid connection loosening or displacement, and this stable connection structure can effectively maintain the stability of the long crystal interface 520 and prevent defects of the crystal 2003 caused by instability of the support platform.

[0077] According to some embodiments of the present application, please refer to Figure 3 and Figure 4 The crystal growth device 1000 further comprises a temperature detection unit 600, which is located in 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 long crystal interface 520, and the heater 300 responds to the temperature detection unit 600.

[0078] The temperature detection unit 600 refers to a device for real-time monitoring of temperature changes near the long crystal interface 520, and the temperature detection unit 600 can adopt a thermocouple, an infrared thermometer or an optical fiber temperature sensor. The temperature detection unit 600 is located in the holding furnace 100 and outside the crucible 200, which means that the temperature detection unit 600 adopts a non-invasive layout to obtain temperature information, avoids direct contact between the temperature detection unit 600 and the melt or the crystal 2003, and prevents pollution of the growth environment; at the same time, the temperature detection unit 600 is protected from erosion by high-temperature melt, thereby ensuring the stability and reliability of the monitoring process.

[0079] The detection position of the temperature detection unit 600 is at the same height as the crystal growth interface 520, specifically, the detection point of the temperature detection unit 600 is accurately aligned with the crystal 2003 precipitation area in the direction perpendicular to the gravity. This design can effectively eliminate the temperature monitoring delay or data error caused by height deviation, and ensure that the temperature detection unit 600 collects real-time temperature information at the crystal growth interface 520, providing accurate data support for subsequent temperature regulation.

[0080] The heater 300 can build a complete closed-loop control circuit in response to the design of the temperature detection unit 600. The closed-loop control circuit can be realized by a closed-loop control circuit or a programmable logic controller (PLC), and the closed-loop control circuit can dynamically adjust the heating power of the heater 300 based on the real-time data transmitted by the temperature detection unit 600: when the temperature detection unit 600 detects that the temperature deviates from the preset value, the closed-loop control circuit will compensate for heat loss or inhibit heat accumulation in time, thereby maintaining the constant state of the temperature of the crystal growth interface 520 and ensuring the thermodynamic stability of the crystal 2003 growth.

[0081] By setting the temperature detection unit 600 in the holding furnace 100, a complete temperature real-time monitoring and feedback closed-loop control system is built. The temperature detection unit 600 is accurately deployed outside the crucible 200, and the detection position height of the temperature detection unit 600 is accurately calibrated to be consistent with the crystal growth interface 520, which can directly collect the thermal radiation signal of the corresponding area and reflect the temperature state of the crystal 2003 precipitation core area in real time. Since the temperature of the crystal growth interface 520 directly determines the growth rate and solid-liquid interface morphology of the crystal 2003, this accurate 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 instructions according to the preset temperature threshold to drive the heater 300 to dynamically adjust the output power and accurately compensate for the thermal field fluctuation caused by the change in the volume of the melt zone.

[0082] Moreover, this design cooperates with the segmented structure of the containing cavity 210, which not only guarantees the stability of the thermal field from the structural level, but also actively suppresses the instability of the thermal field through closed-loop control, effectively maintaining the thermodynamic balance and solid-liquid interface morphology stability during the growth of the crystal 2003, reducing the generation of microscopic defects, and further improving the growth quality of the crystal 2003.

[0083] In practical application, the position of the 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 material of the crystal 2003, the horizontal plane at the same height as the detection position of the temperature detection unit 600 is located in the second section 212, and the horizontal plane at the same height as the detection position of the temperature detection unit 600 is located in the second section 212. The part of the second section 212 is the growth interface 520. Correspondingly, in the case that the heater 300 continuously heats and keeps the detection result of the temperature detection unit 600 relatively stable, the upper end surface of the melt zone is the dissolution interface 510.

[0084] In order to ensure that the position of the upper end surface of the melt zone is in the first section 211 and the position of the lower end surface of the melt zone is in the second section 212, the detection position of the temperature detection unit 600 and the position of the heater 300 can be limited. For example, the projection of the detection position of the temperature detection unit 600 along the direction perpendicular to the gravity direction is located in the second section 212, the projection of the upper end surface of the heater 300 along the direction perpendicular to the gravity direction is located in the first section 211, the projection of the lower end surface of the heater 300 along the direction perpendicular to the gravity direction is located in the second section 212, the extreme position of the lower end surface of the heater 300 is flush with the upper end surface of the second section 212, and the extreme position of the upper end surface of the heater 300 cannot be flush with the lower end surface of the second section 212, but must maintain a certain distance from the lower end surface of the second section 212.

[0085] According to some embodiments of the present application, please refer to Figure 3 and Figure 4 , there is a gap between the temperature detection unit 600 and the outer circumferential surface of the crucible 200.

[0086] The gap between the temperature detection unit 600 and the outer circumferential surface of the crucible 200 refers to the physical separation between the temperature detection unit 600 and the outer circumferential surface of the crucible 200, and the temperature detection unit 600 does not directly contact the outer circumferential surface of the crucible 200.

[0087] By spacing the temperature detection unit 600 from the outer circumferential surface of the crucible 200, the temperature detection unit 600 avoids applying mechanical force to the crucible 200 through physical separation, prevents deformation or position deviation of the crucible 200 due to contact pressure, and ensures the structural stability of the crucible 200 in a high-temperature growth environment. At the same time, the non-contact gap setting can block the direct heat conduction between the temperature detection unit 600 and the crucible 200, avoid the interference of the heat conduction of the crucible 200 on the temperature of the temperature detection unit 600 itself, ensure that the heat radiation signals collected by the temperature detection unit 600 only reflect the true temperature state of the growth interface 520, and improve the accuracy of the temperature monitoring data.

[0088] In addition, the gap between the temperature detection unit 600 and the crucible 200 can also provide a buffer space for thermal expansion of the crucible 200 at high temperature, so as to avoid collision or extrusion between the temperature detection unit 600 and the crucible 200 during thermal expansion and contraction, and further ensure the safety and stability of the equipment operation.

[0089] According to some embodiments of the present application, please refer to Figure 3 and Figure 4 The crystal growth device 1000 further comprises a heat shield 700, which is sleeved on the outer circumferential side of the crucible 200, and the side of the heat shield 700 facing the crucible 200 is provided with a mounting portion 710, and the heater 300 is fixed to the mounting portion 710.

[0090] The heat shield 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 shield 700 is sleeved on the outer circumferential side of the crucible 200, which can effectively block the thermal interference of the environment in the heat preservation furnace 100 on the crucible 200, significantly reduce the loss of heat to the outside through radiation and convection, and create a stable heat preservation environment for the inside of the crucible 200.

[0091] The mounting portion 710 is a supporting and positioning structure arranged on the inner side of the heat shield 700, which can be realized by groove, boss, bracket or clamping groove, etc. The core purpose is to provide accurate positioning reference and stable bearing point for the heater 300, so that the relative position between the heater 300 and the first segment 211 of the melting zone material 2002 remains constant, and the heat input is more concentrated and controllable. Avoiding the heat conduction interference that may be caused by directly fixing the heater 300 to the crucible 200. The heater 300 is fixed to the mounting portion 710 by mechanical connection methods such as bolts, buckles and welding, so as to ensure that it will not be displaced due to mechanical vibration or thermal expansion during the growth of the crystal 2003, and to ensure the stability of the installation position.

[0092] The physical heat shield barrier is formed outside the crucible 200 by the heat shield 700, the heat loss is reduced, the precise positioning and fixing of the heater 300 are realized by the mounting part 710, the stability of the temperature of the melting zone material 2002 is maintained, the dynamic balance of the dissolving interface 510 and the crystal growth interface 520 is provided, and the micro defects caused by temperature fluctuations are effectively reduced. The above technical scheme significantly improves the heat field distribution in the crystal 2003 growth process, makes the temperature control of the melting zone material 2002 more accurate, enhances the stability of the solid-liquid interface, thereby reducing the probability of component segregation, interface bending and internal defects of the crystal 2003, and improving the integrity and component uniformity of the crystal 2003. At the same time, the scheme and the heater 300, the crucible 200, the containing cavity 210 and other structures in the crystal growth device 1000 complement each other, and jointly guarantee the continuity and quality stability of the crystal 2003 growth.

[0093] According to some embodiments of the present application, please refer to Figure 3 and Figure 4 The containing cavity 210 extends to the top end of the crucible 200 along the gravity direction and forms a first opening, and the crystal growth device 1000 comprises a crucible plug 800, and the crucible plug 800 is arranged on the first opening.

[0094] The first opening is a channel structure formed at the top end of the containing cavity 210 in the gravity direction, and the cross section can adopt various forms such as circular, elliptical, rectangular and the like. The first opening provides a convenient path for directly filling raw materials from the top during the charging process, conforms to the natural accumulation characteristics of the raw materials, and reduces the operation difficulty.

[0095] The crucible plug 800 is a sealing component for sealing the first opening, which can be made of graphite, ceramic or metal composite material, etc., and the outer contour thereof is accurately matched with the geometric shape of the first opening to realize the sealing effect of close fitting. The sealing design can build a dynamic sealing barrier, which can isolate the invasion of impurities such as oxygen and moisture from the outside, avoid the pollution of the melt, and maintain the stability of the atmosphere and heat field in the holding furnace 100, and reduce the interference of the external environment on the growth of the crystal 2003.

[0096] Through the matching design of the accommodating cavity 210 and the crucible plug 800, the two core problems of raw material loading complexity and melt exposure are systematically solved. The structure that the accommodating cavity 210 extends to the top end of the crucible 200 makes the charging process not need to adapt to the complex internal structure, and the raw material can be directly filled from top to bottom, which simplifies the operation process, reduces the probability of impurity introduction in the charging process, and improves the stability of the initial conditions of the crystal 2003 growth; the sealing effect of the crucible plug 800 blocks the influence of external adverse 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 in the holding furnace 100, effectively reducing the volume fluctuation of the melting zone and the disturbance of the crystal growth interface 520, and significantly improving the continuity and quality uniformity of the crystal 2003 growth.

[0097] In actual operation, the operator can directly fill the raw material into the accommodating cavity 210 through the first opening during the charging stage; after the charging is completed and before the crystal 2003 growth is started, the crucible plug 800 is lightly placed at the first opening to complete the sealing, ensuring the stability of the growth environment in the crucible 200, which is convenient to operate and reliable in sealing.

[0098] The embodiment of the present application also provides a crystal growth method applied to the crystal growth device as described above, please refer to Figure 7 , the crystal growth method specifically includes the following steps: Step S10, the melting zone material and the solid polycrystalline raw material are loaded into the accommodating cavity; Please refer to Figure 3 and Figure 4 During the charging process, the operator fills the raw material from top to bottom through the first opening at the top end of the crucible 200, which conforms to the natural accumulation characteristics of the raw material and simplifies the operation process.

[0099] The melting zone material 2002 is initially filled in the lower part of the first section 211 to the upper end surface or the upper part of the second section 212 of the accommodating cavity 210, and the solid polycrystalline raw material 2001 is stacked above the melting zone material 2002 in the first section 211, forming a stable up-down distribution structure of solid raw material-melting zone material 2002, which lays a foundation for subsequent dissolution replenishment and crystal 2003 growth.

[0100] After the charging is completed, the crucible plug 800 is covered at the first opening, and the sealing is realized through the precise fitting of the crucible plug 800 and the first opening, which isolates the invasion of impurities such as oxygen and moisture from the outside, and at the same time maintains the stability of the atmosphere in the holding furnace 100.

[0101] Step S20, heating the melting zone material through the heater; Please refer to Figure 3 and Figure 4The heater 300 is precisely positioned by the mounting portion 710 on the inner side of the heat shield 700, and the heating area thereof precisely corresponds to the height of the molten zone material 2002 in the accommodating cavity 210, so as to ensure that the heat is concentrated on the molten zone material 2002 and energy waste is avoided.

[0102] During the heating process, the heat shield 700 plays a role of heat barrier to reduce heat loss to the outside of the holding furnace 100, and simultaneously optimizes the uniformity of the heat field distribution in the furnace. The temperature detection unit 600 is arranged outside the crucible 200, and the detection position thereof is kept at the same height as the subsequent crystal growth interface 520 and is provided with a gap from the outer peripheral surface of the crucible 200. The temperature detection unit 600 collects the thermal radiation signal of the molten zone 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 instruction according to a preset temperature threshold, and drives the heater 300 to dynamically adjust the output power, so as to form a closed-loop control loop. The temperature of the lower end surface of the molten zone, i.e., the subsequent crystal growth interface 520, is stabilized in a preset range required for the growth of the crystal 2003, so as to avoid abnormal molten zone morphology caused by temperature fluctuation. After the heater 300 is started, the outer periphery of the first section 211 of the crucible 200 is heated, so that the molten zone material 2002 in the first section 211 is kept in a molten state and forms a molten zone. With the advancement of the heating process, the molten zone expands upward to contact the solid polycrystalline raw material 2001 above, and forms a stable dissolution interface 510, which is always located in the first section 211 with a large cross section, thereby providing a guarantee for efficient dissolution of the solid raw material.

[0103] In step S30, the growth platform is moved downward relative to the crucible, so that the solid polycrystalline raw material is continuously dissolved into the molten zone material, and the substances in the molten zone material continuously precipitate on the growth platform to form a crystal, until the crystal growth is completed.

[0104] Please refer to Figure 3 and Figure 4 The downward movement of the growth platform 400 is realized by an external driving mechanism, such as a linear motor, a screw nut cooperation, etc. During the downward movement, the solid raw material is dissolved and supplied, and the crystal 2003 is precipitated and grown, until the growth of the target crystal 2003 is completed.

[0105] Firstly, the growth platform 400 is adjusted to move to an initial position, so that the lower end of the melt zone material 2002 is in contact with the seed crystal on the growth platform 400; when the temperature at the contact position of the seed crystal and the melt zone material 2002 is lower than the melting point of the crystal 2003 material, the solute in the melt zone material 2002 is directionally solidified on the surface of the seed crystal to form the crystal 2003, and the contact interface between the crystal 2003 and the melt zone material 2002 is defined as the growth interface 520, which is always located in the second section 212 with a small cross section; then, the power of the heater 300 is kept stable, and the growth platform 400 is slowly moved downward: on the one hand, the solid polycrystalline raw material 2001 in the first section 211 has a larger cross-sectional area and a sufficient contact area with the melt zone, and is continuously dissolved at the dissolution interface 510 to dynamically supplement the solute to the melt zone to make up for the consumption of the melt caused by the growth of the crystal 2003; on the other hand, the solute in the melt zone material 2002 is transported to the bottom growth interface 520 through diffusion or convection, and continuously precipitates to make the crystal 2003 grow layer by layer; during the whole process, the melt zone is always kept in a fixed state until the solid polycrystalline raw material 2001 is completely dissolved to form the crystal 2003 with a target size.

[0106] Through the differentiated cross-sectional design of the accommodating cavity 210, the raw material distribution in step S10 and the movement of the growth platform 400 in step S30 form a synergy: the large cross section of the first section 211 enlarges the contact area between the solid polycrystalline raw material 2001 and the melt zone, significantly improving the dissolution rate; the small cross section of the second section 212 makes the growth rate of the growth interface 520 relatively controllable, realizes the dynamic balance of the “melt replenishment rate-crystal 2003 consumption rate”, avoids the growth rate limitation caused by insufficient replenishment, or the melt zone expansion caused by excessive replenishment, and guarantees the growth efficiency and reduces defects such as component segregation and interface bending.

[0107] In addition, the accommodating cavity 210 adapted to the above cross-sectional differentiation design keeps the melt zone in the crucible 200 fixed, and realizes the continuous growth of the crystal 2003 by moving the growth platform 400. This design avoids the dynamic instability of the melt zone volume caused by the movement of the melt zone, improves the stability and uniformity of the melt zone volume, and further reduces the problems of interface bending and component segregation; while guaranteeing the growth efficiency, it provides a guarantee for the further optimization of the quality of the crystal 2003.

[0108] Further, the "closed-loop temperature control formed by feedback regulation of the temperature detection unit 600 and the heater 300" of step S20 is deeply adapted with the design of "fixed melting zone + moving platform" of step S30. On the one hand, the closed-loop control accurately locks the temperature of the long crystal interface 520, avoiding the instability of the melting zone form caused by temperature fluctuations. On the other hand, the fixed melting zone design avoids the volume fluctuation caused by the traditional "moving melting zone", combined with the heat preservation 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 atomic ordered arrangement of the crystal 2003, further reducing the micro defects such as dislocations and twins.

[0109] The above describes the principles and embodiments of the present application using specific examples. The above examples are only used to help understand the method of the present application and its core idea. It should be noted that for ordinary skilled persons in the art, without departing from the principles of the present application, the present application can be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the present application.

[0110] The following specific examples are given to supplement the content of the present application.

[0111] Example 1 This example is used to prepare a cadmium telluride (CdTe) crystal with a diameter of 30 mm.

[0112] Please refer to Figure 3 and Figure 4 Place the heat preservation furnace 100 on a platform, install the heater 300 at the installation part 710 of the heat shield 700, and then install the heater 300 together with the heat shield 700 inside the heat preservation furnace 100, and pay attention to keep the heater 300 concentric with the heat preservation furnace 100.

[0113] Install the growth platform 400 at the center of the bottom circular hole of the heat preservation furnace 100, then slowly place the crucible 200 over the growth platform 400, then slowly lower the seed crystal from the top of the crucible 200 until it falls on the top of the growth platform 400, then place the melting zone material 2002 on top of the seed crystal, and finally place the solid polycrystalline raw material 2001 above the melting zone material 2002.

[0114] After all the raw materials are placed, use the crucible plug 800 to seal the tail of the crucible 200.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] Example 2 This embodiment is used to prepare cadmium zinc telluride (Cd0.96Zn0.04Te) crystals with a diameter of 50 mm.

[0119] 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.

[0120] 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.

[0121] After all the raw materials have been placed, use crucible stopper 800 to seal the tail of crucible 200.

[0122] In this embodiment, when designing the size of the melting zone, the diameter of the crystal growth interface 520 at the lower part of the melting 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 and the crystal growth interface 520 is 5:1. By consulting the phase diagram, the composition of the melting zone is designed so that the crystal melting point is 950℃, and the temperature rising program of the heater 300 is set, so that the heater 300 is raised to 1000℃ for 24h, at this time, the temperature detection unit 600 shows 962℃, which means that the temperature at the seed crystal position has been higher than the designed crystal melting point temperature, and the seed crystal will be partially melted, which meets the design requirements.

[0123] After the heater 300 is raised to high temperature and kept for 72h, through the control program, the growth platform 400 is slowly lowered, at this time, the solid polycrystalline raw material 2001 at the upper part of the melting zone material 2002 will gradually dissolve, and the crystal growth interface 520 below will gradually complete the crystal growth, and the crystal growth rate is equal to the lowering speed of the growth platform 400. In this embodiment, the lowering speed of the growth platform 400 is set to 2.8mm / h, and as the growth platform 400 is lowered to the required position, the growth of the entire crystal 2003 is completed, and it can be understood that the crystal includes the seed crystal and the part grown on the surface of the seed crystal.

[0124] After the crystal growth is completed, the power of the heater 300 is turned off, and the whole system is cooled down. After the temperature detection unit 600 detects that the temperature has dropped to room temperature, the grown crystal 2003 is taken out.

[0125] Comparative Example 1 This comparative example is used to produce a cadmium telluride (CdTe) crystal with a diameter of 30mm, which has no difference from the embodiment 1 except that the shape of the crucible 200 is different. The crucible 200 in the comparative example adopts the traditional equal-diameter crucible method, that is, the diameters of the crystal growth interface 520 and the dissolution interface 510 are equal.

[0126] Please refer to Figure 8 The heat preservation furnace 100 is placed on a platform, the heater 300 is installed at the installation part 710 of the heat shield 700, and then the heater 300 is installed together with the heat shield 700 in the heat preservation furnace 100, and attention is paid to keep the heater 300 concentric with the heat preservation furnace 100.

[0127] The growth platform 400 is installed at the center of the bottom round hole of the heat preservation furnace 100, then the crucible 200 is slowly placed on the growth platform 400, and then the seed crystal is slowly lowered from the top of the crucible 200 and finally falls on the top of the growth platform 400, and then the melting zone material 2002 is placed on the upper part of the seed crystal, and finally the solid polycrystalline raw material 2001 is placed above the melting zone material 2002.

[0128] After all the raw materials are placed, the tail of the crucible 200 is sealed with the crucible plug 800.

[0129] In this embodiment, when designing the size of the melt zone, the diameter of the crystal growth interface 520 at the lower part of the melt zone is designed to be 30 mm, and the diameter of the dissolution interface 510 is also designed to be 30 mm, at which time the area ratio of the dissolution interface 510 to the crystal growth interface 520 is 1:1. By consulting the phase diagram, the composition of the melt zone is designed so that the crystal melting point is 950°C, and the temperature rising program of the heater 300 is set so that the heater 300 is raised to 1000°C in 24 h, at which time the reading of the temperature detection unit 600 is 962°C, indicating that the temperature at the position of the seed crystal has been higher than the designed crystal melting point temperature, and the seed crystal will be partially melted, which meets the design requirements.

[0130] After the heater 300 is raised to a high temperature and kept for 72 h, the growth platform 400 is slowly lowered by controlling the program, at which time the solid polycrystalline raw material 2001 at the upper part of the melt zone material 2002 will gradually dissolve, and the crystal growth interface 520 below will gradually complete the crystal growth, and the crystal growth speed is equal to the lowering speed of the growth platform 400. In this embodiment, the lowering speed of the growth platform 400 is set to be 0.8 mm / h, and as the growth platform 400 is lowered to the required position, the growth of the entire crystal 2003 is completed, and it can be understood that the crystal 2003 includes the seed crystal and the part grown on the surface of the seed crystal.

[0131] After the crystal growth is completed, the power supply of the heater 300 is turned off, and the entire system is cooled down. After the reading of the temperature detection unit 600 is reduced to room temperature, the grown crystal 2003 is taken out.

[0132] Comparative Example 2 This comparative example is used to prepare a tellurium-zinc-cadmium (Cd0.96Zn0.04Te) crystal with a diameter of 50 mm, which has no difference from the embodiment 2 except that the shape of the crucible 200 is different. The crucible 200 in the comparative example adopts the traditional equal-diameter crucible method, i.e., the diameters of the crystal growth interface 520 and the dissolution interface 510 are equal.

[0133] Please refer to Figure 8 The heat preservation furnace 100 is placed on a platform, the heater 300 is installed at the installation part 710 of the heat shield 700, and then the heater 300 is installed together with the heat shield 700 inside the heat preservation furnace 100, and attention is paid to keep the heater 300 concentric with the heat preservation furnace 100.

[0134] The growth platform 400 is installed at the center of the bottom circular hole of the heat preservation furnace 100, then the crucible 200 is slowly placed on the growth platform 400, and then the seed crystal is slowly lowered from the top of the crucible 200 and finally falls on the top of the growth platform 400, and then the melt zone material 2002 is placed on the upper part of the seed crystal, and finally the solid polycrystalline raw material 2001 is placed above the melt zone material 2002.

[0135] After all the raw materials are placed, the tail of the crucible 200 is sealed with the crucible plug 800.

[0136] In this embodiment, when designing the size of the melting zone, the diameter of the crystal growth interface 520 at the lower part of the melting 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 and the crystal growth interface 520 is 1:1. By consulting the phase diagram, the composition of the melting zone is designed so that the crystal melting point is 950℃, and the temperature rising program of the heater 300 is set, so that the heater 300 is raised to 1000℃ for 24h, at this time, the temperature detection unit 600 shows 962℃, indicating that the temperature at the seed crystal position is higher than the designed crystal melting point temperature, and the seed crystal will be partially melted, which meets the design requirements.

[0137] After the heater 300 is heated to high temperature and kept for 72h, the growth platform 400 is slowly lowered through the control program, at this time, the solid polycrystalline raw material 2001 at the upper part of the melting zone material 2002 will gradually dissolve, and the crystal growth interface 520 below will gradually complete the crystal growth, and the crystal growth rate is equal to the lowering speed of the growth platform 400. In this embodiment, the lowering speed of the growth platform 400 is set to 0.7mm / h, and as the growth platform 400 is lowered to the required position, the growth of the entire crystal 2003 is completed, and it can be understood that the crystal 2003 includes the seed crystal and the part grown on the surface of the seed crystal.

[0138] After the crystal growth is completed, the power of the heater 300 is turned off, and the entire system is cooled. After the temperature detection unit 600 detects that the temperature has dropped to room temperature, the grown crystal 2003 is taken out.

[0139] In order to observe the implementation effect of the present application, the following experiments are also carried out for the crystal growth results.

[0140] I. Crystal grain results of the grown crystal After the grown crystals 2003 in Examples 1, 2 and Comparative Examples 1, 2 are taken out, they are cut along the axial direction to cut out crystal wafers with the same thickness, and the crystal grain distribution on the cut surface is observed, and the results are shown in Figure 9 , wherein, Figure 9 is a cut surface diagram of the crystal prepared in Example 1 of the present application, Figure 10 is a cut surface diagram of the crystal prepared in Comparative Example 1 of the present application, Figure 11 is a cut surface diagram of the crystal prepared in Example 2 of the present application, Figure 12 is a cut surface diagram of the crystal prepared in Comparative Example 1 of the present application.

[0141] Comparison Figure 9 and Figure 10 , Figure 11 and Figure 12As can be seen, the crystal 2003 grown in Example 1 and Example 2, the melting zone part is subjected to shutdown cooling after the end of crystal growth, belongs to rapid solidification, and thus the melting zone part is polycrystal, which is a normal phenomenon. The target crystal grown below has uniform color, and no grain boundary and polycrystal are observed. The crystal 2003 grown in Comparative Example 1 and Comparative Example 2 has part of large grains, but has grain boundary and produces polycrystal.

[0142] II. Comparison of crystal growth efficiency By using the method in the present application, the crystal growth speed is obviously greater than that of the traditional crystal growth method, and the speed comparison is summarized in the following table: Table 1. Comparison of crystal growth speed of examples and comparative examples

[0143] As can be seen from the grain results of Example 1, 2 and Comparative Example 1, 2, after using the method in the present application, because the dissolution interface area is much greater than the crystal growth interface, sufficient dissolution speed is provided, and solute transmission is relatively sufficient, so the grain of the grown crystal 2003 is obviously better than that of the traditional crystal growth method.

[0144] As can be seen from the comparison of the crystal growth speed, after using the area asymmetric dissolution interface 510 and the crystal growth interface 520, the crystal growth speed is greatly improved, and the crystal growth efficiency can be effectively improved.

[0145] In summary, by using the crystal growth method in the present application, the crystal growth speed can be obviously improved, and large-size single crystal can be obtained, and the effect is obvious.

Claims

1. A crystal growing apparatus (1000) characterized by, The application relates to a heat preservation furnace (100), a crucible (200) arranged in the heat preservation furnace (100), an accommodating cavity (210) in the crucible (200) for accommodating a molten zone material (2002) and a solid polycrystal raw material (2001), the accommodating cavity (210) comprising a first section (211) and a second section (212) arranged along a gravity direction, the first section (211) being located above the second section (212) and being in communication with the second section (212), the cross-sectional area of the first section (211) perpendicular to the gravity direction being greater than the cross-sectional area of the second section (212) perpendicular to the gravity direction, the solid polycrystal raw material (2001) being in contact with the molten zone material (2002) to form a dissolution interface (510), the dissolution interface (510) being located in the first section (211), a heater (300) arranged in the heat preservation furnace (100) and located at the outer periphery of the first section (211), the heater (300) being used for heating the molten zone material (2002) in the first section (211), and a growth platform (400) slidably connected with the crucible (200) along the gravity direction and extending into the second section (212), the growth platform (400) being used for supporting a crystal (2003), the crystal (2003) being in contact with the molten zone material (2002) to form a crystal growth interface (520), the crystal growth interface (520) being located in the second section (212). The ratio of the cross-sectional area of the first section (211) perpendicular to the gravity direction to the cross-sectional area of the second section (212) perpendicular to the gravity direction is 1.5:1 to 10:

1. The accommodating cavity (210) comprises a third section (213) arranged along the gravity direction, the third section (213) being located between the first section (211) and the second section (212) and being in communication with the first section (211) and the second section (212). The cross-sectional area of the third section (213) perpendicular to the gravity direction gradually decreases along the direction in which the first section (211) points to the second section (212). The accommodating cavity (210) comprises a fourth section (214) arranged along the gravity direction, the fourth section (214) being located below the second section (212), and the cross-sectional area of the fourth section (214) perpendicular to the gravity direction being greater than the cross-sectional area of the second section (212) perpendicular to the gravity direction.

2. The crystal growing apparatus (1000) according to claim 1, characterized in that The outer periphery of the growth platform (400) is slidably matched with the hole wall surface of the second section (212), and a gap exists between the outer periphery of the growth platform (400) and the hole wall surface of the fourth section (214).

3. The crystal growing apparatus (1000) according to claim 1, characterized in that The growth platform (400) comprises a bottom support (410) for supporting the crystal (2003), and the bottom support (410) is made of graphite. ​ 4. The crystal growing apparatus (1000) according to claim 1, characterized in that ​ ​ 5. The crystal growing apparatus (1000) according to claim 1, characterized in that ​ 6. The crystal growing apparatus (1000) according to claim 5, characterized in that The growth platform (400) comprises a support base (420), one end of the base (410) is connected with the support base (420), the other end of the base (410) extends into the second section (212) and is used for supporting the crystal (2003), and the support base (420) is made of ceramic material.

7. Crystal growing apparatus (1000) according to claim 6, characterized in that One of the base (410) and the support base (420) is provided with a threaded column (431), and the other is provided with a mounting hole (432), and the threaded column (431) is threadedly matched with the mounting hole (432).

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

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

10. The crystal growing apparatus (1000) according to any one of claims 1 to 7, characterized in that The crystal growth device (1000) further comprises a heat shield (700), the heat shield (700) is sleeved on the outer circumferential side of the crucible (200), one side of the heat shield (700) towards the crucible (200) is provided with a mounting portion (710), and the heater (300) is fixed to the mounting portion (710).

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

12. A method of crystal growth, characterized by, The crystal growth method is applied to the crystal growth device according to any one of claims 1 to 11, and the crystal growth method comprises: loading a melting zone material and a solid polycrystalline raw material into the containing cavity; heating the melting zone material by the heater; moving the growth platform downward relative to the crucible, so that the solid polycrystalline raw material is continuously dissolved into the melting zone material, and the substances in the melting zone material continuously precipitate on the growth platform to form a crystal, until the crystal growth is completed.

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