Equipment and method for growing multiple crystals in a single furnace

Abstract

This application provides an apparatus and method for growing multiple crystals in a single furnace. The apparatus includes: a furnace body with at least three temperature zones arranged from top to bottom, the temperature of the top temperature zone being higher than that of the bottom temperature zone; a temperature control unit disposed within each temperature zone; a heat insulation layer disposed between two adjacent temperature zones, with an opening in the middle of the heat insulation layer, the top of the opening projected onto a horizontal plane as a first projection, and the bottom of the opening projected onto a horizontal plane as a second projection, the second projection covering the first projection; a down-draft tube sequentially penetrating the opening of each heat insulation layer, with at least two crucibles arranged from top to bottom inside, each crucible used to hold raw materials for one type of crystal and corresponding to one temperature zone; a heat-insulating material filled between the down-draft tube and the crucible, the thermal conductivity of which decreases as the temperature decreases; and a drive unit connected to the down-draft tube. The apparatus and method for growing multiple crystals in a single furnace provided by this application are simple, convenient, and highly efficient, and can significantly reduce the cost of crystal growth.

Description

Technical Field

[0001] This application relates to the field of crystal growth technology, and in particular to an apparatus and method for growing multiple crystals in a single furnace. Background Technology

[0002] Single crystals are widely used in daily life and industry, such as single-crystal silicon (Si), sapphire (Al₂O₃), and bismuth germanate (Bi₄Ge₂O₃). 12 Cesium iodide (CsI), gallium oxide (Ga2O3), yttrium aluminum garnet (Y3Al5O) 12 Based on the physicochemical characteristics of these crystals, various single crystal growth methods have been developed. Common single crystal growth methods include the Czochralski method, Bridgman method, flux method, Czochralski method, heat exchange method, temperature gradient method, guided mode method, micro-pull-down method, aqueous solution method, and floating zone method. If the crystal is a homologous melting crystal, it means that the crystal has a definite melting point, and the Czochralski method, Bridgman method, Czochralski method, heat exchange method, temperature gradient method, guided mode method, etc., can be selected. If the crystal is a heterologous melting crystal, the flux method, aqueous solution method, etc., can be used.

[0003] Traditional methods for growing large-size single crystals all involve growing one type of crystal in a single furnace. Some techniques, such as the Bridgman multi-crucible method, can grow multiple crystals in a single furnace, but these multiple crystals have the same or very similar melting points. The aforementioned single-crystal silicon, bismuth germanate, cesium iodide, gallium oxide, and sapphire are all homogeneous melting crystals with melting points of 1410°C, 1050°C, 621°C, 1820°C, and 2040°C, respectively. Growing these single crystals requires raising the crystal furnace to a high temperature to fully melt the raw materials above their respective melting points before lowering it below the melting points for growth. Because the crystal growth cycle is long, the electricity and time costs are very high. The larger the single crystal, the higher the electricity and time costs. The Bridgman method and temperature gradient method have relatively slow growth rates. Therefore, for the same melting point and size, the electricity and time costs of crystal growth using these slower growth methods are usually relatively higher. Therefore, there is an urgent need for a more efficient crystal growth method. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide an apparatus and method for growing multiple crystals in a single furnace, so as to solve the related problems mentioned in the background art.

[0005] A first aspect of this application provides an apparatus for growing multiple crystals in a single furnace, comprising: a furnace body, wherein the interior of the furnace body is provided with at least three temperature zones from top to bottom, the temperature of the temperature zone near the top of the furnace body being higher than the temperature of the temperature zone near the bottom of the furnace body; a temperature control unit disposed in each temperature zone for controlling the temperature of the temperature zone; a heat insulation layer disposed between two adjacent temperature zones, wherein the heat insulation layer has an opening in the middle, the orthographic projection of the side of the opening near the top of the furnace body on a horizontal plane being a first projection, and the orthographic projection of the side of the opening near the bottom of the furnace body on a horizontal plane being a second projection, the second projection covering the first projection; a down-draft tube located inside the furnace body, sequentially penetrating the opening of each heat insulation layer, wherein the down-draft tube is provided with at least two crucibles from top to bottom, each crucible being used to hold raw material for one type of crystal and corresponding to one temperature zone; a heat insulation material is filled between the down-draft tube and the crucible, the thermal conductivity of the heat insulation material decreasing as the temperature decreases; and a drive unit connected to the down-draft tube for driving the down-draft tube to move up and down.

[0006] Furthermore, the heat insulation layer includes a first heat insulation plate and a second heat insulation plate stacked together. The first heat insulation plate has a first through hole in the middle, and the second heat insulation plate has a second through hole in the middle. The size of the second through hole is larger than the size of the first through hole, and the first through hole and the second through hole form the opening.

[0007] Furthermore, at least one of the insulation layers near the top of the furnace body is a hollow alumina refractory brick, and the remaining insulation layers are alumina fiber bricks.

[0008] Furthermore, the insulation material is zirconium oxide powder.

[0009] Furthermore, the drive unit is a lifting platform, and the temperature control unit includes a temperature controller and a heating module.

[0010] Furthermore, the temperature difference between adjacent temperature zones near the top of the furnace body is greater than or equal to 100°C, and the temperature difference between adjacent temperature zones near the bottom of the furnace body is less than or equal to 50°C.

[0011] Furthermore, the driving unit drives the lower tube to rise and fall at a speed of 0.01 mm / h to 40 cm / min.

[0012] A second aspect of this application provides a method for growing multiple crystals in a single furnace, using the apparatus for growing multiple crystals in a single furnace as described in the first aspect above. The method includes: driving a guide tube upward via a driving unit, placing different crystal raw materials into crucibles at different heights within the guide tube; driving the guide tube downward via the driving unit, aligning the bottom of the crucible with the top of the opening in the insulation layer, and raising the temperature of the temperature zone above the melting point of the corresponding crystal through a temperature control unit; driving the guide tube upward a preset distance via the driving unit to melt the material, and after a first preset time, driving the guide tube downward a preset distance via the driving unit for heat preservation; after a second preset time, driving the guide tube downward at a preset speed via the driving unit for crystal growth; and after growth is complete, lowering the temperature of the temperature zone via the temperature control unit, driving the guide tube upward via the driving unit, and removing the crucible to obtain multiple crystals.

[0013] Furthermore, the preset distance is 4cm to 5cm, the first preset time is 4h to 10h, the second preset time is 5h to 10h, and the preset speed is 0.2mm / h to 2mm / h.

[0014] Furthermore, the step of reducing the temperature of the temperature zone by means of the temperature control unit includes: reducing the temperature of the temperature zone to room temperature by means of the temperature control unit at a rate of 10°C / h to 15°C / h.

[0015] As can be seen from the above description, the apparatus and method for growing multiple crystals in a single furnace provided in this application include: a furnace body, the interior of which is provided with at least three temperature zones from top to bottom, the temperature of the temperature zone near the top of the furnace body being higher than the temperature of the temperature zone near the bottom of the furnace body; a temperature control unit, disposed in each temperature zone, for controlling the temperature of the temperature zone; a heat insulation layer, disposed between two adjacent temperature zones, the heat insulation layer having an opening in the middle, the orthographic projection of the side of the opening near the top of the furnace body on the horizontal plane being a first projection, the orthographic projection of the side of the opening near the bottom of the furnace body on the horizontal plane being a second projection, the second projection covering the first projection; a down-draft tube, located inside the furnace body, sequentially penetrating the opening of each heat insulation layer, the down-draft tube having at least two crucibles disposed from top to bottom, each crucible being used to hold the raw material of one type of crystal and corresponding to one temperature zone; a heat insulation material being filled between the down-draft tube and the crucible, the thermal conductivity of the heat insulation material decreasing as the temperature decreases; and a drive unit, connected to the down-draft tube, for driving the down-draft tube to move up and down. By employing a special opening structure in the insulation layer, a micro-convex interface can be provided for crystal growth, along with a region with a small temperature gradient and overall temperature difference. This region is a low-temperature zone for the high-melting-point crystal above and a high-temperature zone for the low-melting-point crystal below, thus meeting the temperature field requirements for the growth of different large-sized crystals. Furthermore, the guide tube is filled with insulation material whose thermal conductivity decreases with temperature. As the guide tube moves downwards, the insulation material and crucible move downwards together. Thus, as the crystal grows, more and more insulation material enters the low-temperature zone, at least partially offsetting the heat dissipation effect of the low-temperature zone, further maintaining the micro-convex shape of the crystal. This allows for the simultaneous growth of different crystals with melting point differences exceeding 1000℃ within a single furnace. This equipment and method for growing multiple crystals in a single furnace is simple and convenient, enabling the simultaneous growth of multiple large-sized single crystals with different melting points in one crystal furnace, significantly reducing manufacturing costs and increasing efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a cross-sectional schematic diagram of an apparatus for growing multiple crystals in a single furnace according to an embodiment of this application;

[0018] Figure 2 This is a cross-sectional schematic diagram of a heat insulation layer in an embodiment of this application;

[0019] Figure 3This is a top cross-sectional view of another apparatus for growing multiple crystals in a single furnace, as described in this application embodiment.

[0020] Figure 4 A photograph of the cerium-doped lanthanum bromide crystal obtained in Example 1 of this application;

[0021] Figure 5 A photograph of cesium iodide crystals obtained in Example 1 of this application;

[0022] Figure 6 This is a graph showing the temperature-furnace relative height variation during crystal growth in Example 1 of this application.

[0023] Figure 7 A photograph of the cerium-doped lanthanum bromide crystal obtained in Comparative Example 1 of this application;

[0024] Figure 8 This is a graph showing the temperature-furnace relative height variation during crystal growth in Comparative Example 1 of this application.

[0025] Reference numerals: 1. Furnace body; 1-1. Temperature zone; 2. Insulation layer; 2-1. Opening; 2-2. First insulation plate; 2-3. First through hole; 2-4. Second insulation plate; 2-5. Second through hole; 3. Downstream pipe; 3-1. Crucible; 4. Temperature control unit Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0027] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] Large-size single crystal growth places high demands on the temperature field. A crucial requirement is maintaining a micro-convex interface throughout the crystal growth process, while keeping the temperature as constant as possible in the upper and lower regions of the temperature gradient zone. For example, patent ZL201510928093.9 describes a method and apparatus for preparing sheet-like single crystals using a vertical moving temperature field gradient method. The multi-temperature zone furnace used in this method can hold multiple ingots and crucibles with different melting points for crystal growth. However, it is difficult to ensure a suitable temperature field for each type of crystal. Furthermore, once multiple crucibles are placed, as crystal growth progresses, the crucibles move towards the lower temperature zone, crystallization begins, and the amount of material in the high-temperature zone decreases while the amount in the low-temperature zone increases. Since the thermal conductivity of most materials increases with decreasing temperature, the significant increase in material and thermal conductivity in the low-temperature zone leads to increased heat dissipation. This results in significant interface movement and changes in interface shape, often becoming a concave interface. Therefore, it is difficult to simultaneously obtain multiple high-quality crystals with different melting points. In fact, the Bridgman method, temperature gradient method, and heat exchange method can all optimize the temperature field using multiple temperature zones in principle; however, due to the stringent requirements of large-size single crystals on the crystal growth temperature field mentioned above, there has never been a report of simultaneously growing two single crystals with a melting point difference of more than 20°C in a single crystal furnace.

[0029] The following describes specific embodiments in conjunction with the appendix. Figures 1 to 8 The technical solution of this application will be described in detail below.

[0030] In some embodiments of this application, an apparatus for growing multiple crystals in a single furnace is provided, such as... Figure 1 As shown, the furnace includes: a furnace body 1, the interior of which is provided with at least three temperature zones 1-1 from top to bottom, wherein the temperature of the temperature zone 1-1 near the top of the furnace body 1 is higher than the temperature of the temperature zone 1-1 near the bottom of the furnace body 1; a temperature control unit 4, disposed in each of the temperature zones 1-1, for controlling the temperature of the temperature zone 1-1; and a heat insulation layer 2, disposed between two adjacent temperature zones 1-1, wherein the heat insulation layer 2 has an opening 2-1 in the middle, the orthographic projection of the side of the opening 2-1 near the top of the furnace body 1 on the horizontal plane is the first projection, and the side of the opening 2-1 near the bottom of the furnace body 1... The orthographic projection of one side onto the horizontal plane is the second projection, which covers the first projection; the down-lead tube 3, located inside the furnace body 1, is arranged to pass through the openings 2-1 of each of the heat insulation layers 2 in sequence; the down-lead tube 3 has at least two crucibles 3-1 arranged from top to bottom inside, each crucible 3-1 is used to hold a raw material of a crystal and corresponds to a temperature zone 1-1; the down-lead tube 3 and the crucibles 3-1 are filled with heat-insulating material, the thermal conductivity of which decreases as the temperature decreases; the drive unit is connected to the down-lead tube 3 and is used to drive the down-lead tube 3 to move up and down.

[0031] like Figure 1 As shown, the equipment includes a furnace body 1, which is a cylindrical structure, such as a cylinder or a quadrangular prism. It has multiple stacked temperature zones 1-1 inside, with the upper temperature zone 1-1 having a higher temperature and the lower temperature zone 1-1 having a lower temperature to form a temperature gradient for crystal growth. The number of temperature zones 1-1 is, for example, three, four, or five, etc., and is not specifically limited. Setting at least three temperature zones 1-1 can meet the growth requirements of at least two crystals with different melting points.

[0032] Each temperature zone 1-1 is equipped with a temperature control unit 4, which includes a temperature controller and a heating module. It can control the temperature of the corresponding temperature zone 1-1. For example, the heating module of the temperature zone 1-1 that is higher in the vertical height can be heated higher. The temperature of these temperature zones 1-1 is adjusted so that the temperature is above the melting point of the crystal being grown. Then, the temperature gradient is measured at specific intervals when the temperature rises or falls. Based on the temperature gradient test results, the temperature control of the heating module is adjusted so that the temperature gradient of different zones can also meet the needs of different crystal growth.

[0033] A heat insulation layer 2 is provided between every two adjacent temperature zones 1-1, meaning that the number of heat insulation layers 2 is less than the number of temperature zones 1-1. This is used to block the temperature of different temperature zones 1-1. The material of the heat insulation layer 2 is, for example, alumina, but is not specifically limited. An opening 2-1 is provided in the middle of the heat insulation layer 2. The opening 2-1 has a structure that is smaller at the top and larger at the bottom. By adopting the special structure of the opening 2-1 of the heat insulation layer 2, a micro-convex interface can be provided for crystal growth, and a region with a small gradient and a small total temperature difference can be provided for crystal growth. This region belongs to the low temperature zone 1-1 for the high melting point crystal above, and to the high temperature zone 1-1 for the low melting point crystal below, thereby meeting the temperature field requirements for the growth of different large-sized crystals.

[0034] The furnace body 1 is also equipped with a down-feed tube 3, which may be cylindrical or quadrangular prism in shape. The down-feed tube 3 also contains stacked crucibles 3-1, the number of which corresponds to the number of insulation layers 2. Each crucible 3-1 is used to hold a type of crystal raw material, such as... Figure 1 As shown, one crucible 3-1 is set in each layer, or as... Figure 3As shown, multiple crucibles 3-1 are set in each layer, and raw materials of crystals with the same or similar melting points are placed in the same layer, which is not limited in specific terms. The space between the crucible 3-1 and the down-feed tube 3 is filled with heat-insulating material, such as zirconia powder. The heat-insulating material with a thermal conductivity that decreases with decreasing temperature is selected to fill the down-feed tube 3. As the down-feed tube 3 moves downward, the heat-insulating material and the crucible 3-1 move downward together. In this way, as the crystal grows, more and more heat-insulating material enters the low-temperature zone 1-1, which can at least partially offset the heat dissipation effect of the low-temperature zone 1-1, and further maintain the micro-convex shape of the crystal. It is possible to grow different crystals with melting point differences of more than 1000℃ simultaneously in one furnace body 1.

[0035] The driving unit is, for example, a lifting platform, which can move the down tube 3 up and down, thereby moving the crucible 3-1, the insulation material, and the crystal. The driving unit drives the down tube 3 to move up and down at a speed of 0.01 mm / h to 40 cm / min. That is, the driving unit can make the down tube 3 move slowly to melt the raw materials and grow the crystal, or it can make the down tube 3 move quickly to pick up and put down the crucible 3-1 and the crystal.

[0036] This single-furnace equipment for growing multiple crystals is simple and convenient, and can grow multiple large-size single crystals with different melting points simultaneously in one crystal furnace, greatly reducing production costs.

[0037] The thermal conductivity of the insulation material used around crucible 3-1 decreases as the temperature decreases. As crystal growth proceeds, more and more insulation material enters the low-temperature zone 1-1 along with crucible 3-1, thus partially or even completely offsetting the heat dissipation effect of the low-temperature zone 1-1. This greatly suppresses the rapid increase in heat dissipation in the low-temperature zone 1-1. When multiple different crystals are growing, the volume of the down-lead tube 3 increases significantly. Therefore, this suppression effect becomes very important, allowing the crystal growth interface to remain in its original position and slightly convex shape, enabling the acquisition of large-size, high-quality crystals. This is completely different from the effect of using ZrO2 powder in some Czochralski processes. Traditional Czochralski processes use ZrO2 powder as an insulating material that remains stationary with the growth crucible 3-1. However, the process characteristics of this equipment are similar to the Bridgman process. The crucible 3-1 moves relative to the temperature field as the growth process progresses. The ZrO2 powder covering the crucible 3-1 naturally moves with the relative movement of the crucible 3-1. This fully utilizes the characteristic that the thermal conductivity of ZrO2 powder decreases with decreasing temperature, and fully meets the temperature field requirements of multiple large-size crystals. Therefore, multiple large-size single crystals with significant differences in melting point can be grown in the same furnace, greatly reducing the power cost, time cost, and site cost of crystal growth.

[0038] In some embodiments, such as Figure 2As shown, the heat insulation layer 2 includes a first heat insulation plate 2-2 and a second heat insulation plate 2-4 stacked together. The first heat insulation plate 2-2 has a first through hole 2-3 in the middle, and the second heat insulation plate 2-4 has a second through hole 2-5 in the middle. The size of the second through hole 2-5 is larger than the size of the first through hole 2-3. The first through hole 2-3 and the second through hole 2-5 form the opening 2-1.

[0039] like Figure 2 As shown, the heat insulation layer 2 can adopt a double-layer heat insulation board design. The first through hole 2-3 of the upper first heat insulation board 2-2 is relatively small, and the second through hole 2-5 of the lower second heat insulation board 2-4 is relatively large. In this way, the first heat insulation board 2-2 can provide a micro-convex interface, while the second heat insulation board 2-4 can provide a region with a small gradient and a small total temperature difference. This region is a low temperature region 1-1 for the high melting point crystals grown above, and a high temperature region 1-1 for the relatively low melting point crystals grown below. Its comprehensive effect can fully meet the temperature field requirements for the growth of large-size crystals, and the opening 2-1 is easy to manufacture.

[0040] In some embodiments, at least one of the heat insulation layers 2 near the top of the furnace body 1 is a hollow alumina refractory brick, and the remaining heat insulation layers 2 are alumina fiber bricks.

[0041] Since the temperature in temperature zone 1-1 is relatively high, the upper insulation layer 2 requires a higher insulation effect. The upper insulation layer 2 is made of hollow alumina refractory brick, which has a good insulation effect, while the lower insulation layer 2 is made of alumina fiber brick, which has a low cost.

[0042] In some embodiments, the temperature difference between adjacent temperature zones 1-1 near the top of the furnace body 1 is greater than or equal to 100°C, and the temperature difference between adjacent temperature zones 1-1 near the bottom of the furnace body 1 is less than or equal to 50°C.

[0043] The temperature difference between adjacent temperature zones 1-1 above is, for example, 100℃, 150℃, 200℃, 300℃, etc., and the temperature difference between adjacent temperature zones 1-1 below is, for example, 50℃, 40℃, 30℃, 20℃, etc., which can improve energy utilization, ensure crystal growth effect, and reduce cost.

[0044] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0045] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0046] Based on the same inventive concept, this application also provides a method for growing multiple crystals in a single furnace, using the apparatus for growing multiple crystals in a single furnace as described in any of the above embodiments, the method comprising:

[0047] S1. Drive the guide tube 3 to rise through the drive unit, and put different crystal raw materials into crucibles 3-1 at different heights in the guide tube 3.

[0048] Control the rapid ascent of the guide pipe 3 to place the raw material.

[0049] S2. The drive unit drives the down tube 3 to descend, so that the bottom of the crucible 3-1 is flush with the top of the opening 2-1 of the heat insulation layer 2, and the temperature control unit 4 raises the temperature of the temperature zone 1-1 to above the melting point of the corresponding crystal growth.

[0050] Control the rapid descent of the downpipe 3. Before raising the temperature, first set the bottom of the crucible 3-1 flush with the top of the opening 2-1 of the insulation layer 2 to prepare for melting the material.

[0051] S3. The drive unit drives the down pipe 3 to rise a preset distance to melt the material. After a first preset time, the drive unit drives the down pipe 3 to fall a preset distance to keep it warm.

[0052] The preset distance is, for example, 4cm to 5cm, and the first preset time is, for example, 4h to 10h. First, the height of crucible 3-1 is raised to melt the material, and then the height of crucible 3-1 is reset for heat preservation.

[0053] S4. After the heat preservation period has passed for a second preset time, the drive unit drives the lead tube 3 to descend at a preset speed to grow crystals.

[0054] The second preset time is, for example, 5h to 10h. After heat preservation, the crystal maintains a slightly convex interface. Then, the lead tube 3 is controlled to slowly descend at a preset speed of, for example, 0.2mm / h to 2mm / h, so that the crystal can grow by cooling.

[0055] S5. After the growth is completed, the temperature of the temperature zone 1-1 is reduced by the temperature control unit 4, and the guide tube 3 is driven to rise by the drive unit to remove the crucible 3-1 and obtain various crystals.

[0056] After the growth reaches the set length or the set time, the growth ends. At this time, the temperature zone 1-1 is controlled to cool down. For example, the temperature of temperature zone 1-1 is reduced to room temperature at a rate of 10°C / h to 15°C / h by the temperature control unit 4. The lead tube 3 is controlled to rise rapidly, and the crucible 3-1 is taken out to obtain various crystals of the finished product.

[0057] This method fully satisfies the temperature field requirements of multiple large-sized crystals, thus enabling the growth of multiple large-sized single crystals with significant melting point differences in the same furnace. This method greatly reduces the electricity, time, and site costs associated with crystal growth.

[0058] Example 1

[0059] Cerium-doped lanthanum bromide (LaBr3:Ce) crystals and cesium iodide (CsI) crystals were grown simultaneously in a single furnace.

[0060] The constructed growth equipment mainly consists of a furnace body, a temperature control unit, and a drive unit. The furnace body has a circular cross-section and three temperature zones from top to bottom, each corresponding to a heating module. There are three heating modules in total, each circular, with Kanthal resistance wire embedded and wrapped inside the module. The outer diameter of each heating module is 30cm and the inner diameter is 14cm. The first heating module is 25cm high, and the second and third heating modules are 20cm high. Double-layer heat insulation plates are installed between the first and second heating modules, as well as between the second and third heating modules. The upper heat insulation plate has an outer diameter of 30cm, an inner diameter of 10cm, and a thickness of 6cm, while the lower heat insulation plate has an outer diameter of 30cm, an inner diameter of 16cm, and a thickness of 5cm. The furnace body is surrounded by a circular furnace shell. The temperature control unit consists of three temperature controllers, each controlling one heating module. The drive unit is connected to the downpipe inside the furnace body and can automatically raise and lower the furnace. The rapid raising and lowering speed can reach 40cm / min, and the slow raising and lowering speed can reach 0.01mm / h.

[0061] 4.87g of anhydrous cerium bromide (99.99% purity) and 92.65g of anhydrous lanthanum bromide (99.99% purity) were mixed and stirred evenly in a glove box, and then placed into a quartz crucible with a pointed cone. The inner diameter of the equal-diameter section of the quartz crucible was 25mm and the height was 80mm. After the raw materials were placed in, the quartz crucible was removed from the glove box and immediately connected to a vacuum pump for vacuum sealing. 84.78g of anhydrous cesium iodide (99.99% purity) was placed into a quartz crucible with a pointed cone in the glove box. The inner diameter of the equal-diameter section of the quartz crucible was 25mm and the height was 80mm. After the quartz crucible was removed from the glove box, it was vacuum sealed.

[0062] The two crucibles were placed in the same alumina down-feed tube. The down-feed tube had an outer diameter of 8 cm, a wall thickness of 5 mm, and a height of 100 cm. The crucible doped with cerium and lanthanum bromide was placed in the upper part of the down-feed tube, and the crucible doped with cesium iodide was placed in the lower part of the down-feed tube. The remaining part of the down-feed tube was filled with ZrO2 powder. The bottoms of the two crucibles were 31 cm apart, and thermocouples were placed at the bottom of the crucibles respectively.

[0063] The lead tube obtained in the above steps is placed in a stainless steel disc. This disc is connected to a mechanical device that can automatically raise and lower the lead tube. The disc is then automatically raised and adjusted so that the bottom of the cesium iodide crucible is flush with the bottom of the second heating module. The thermocouples at the bottom of the two crucibles are connected to a thermometer, and the furnace is sealed. The three heating modules are then heated to 860°C, 710°C, and 370°C, respectively. At this point, the thermocouple temperature at the bottom of the cerium-doped lanthanum bromide crucible is 784°C, and the thermocouple temperature at the bottom of the cesium iodide crucible is 625°C. The disc height is then raised by 5 cm. After 6 hours, the disc height is lowered by 5 cm. After 6 hours, the disc is slowly lowered at a rate of 1 mm / h. After 80 hours, the lowering is stopped. The temperature of each of the three heating modules is reduced to room temperature at a rate of 15°C / h. Then, the crucibles and crystals are removed sequentially.

[0064] Figure 4 The obtained cerium-doped lanthanum bromide crystal, Figure 5 The obtained cesium iodide crystals show that both crystal structures are complete, with few impurities and defects, few cracks, and high quality. Figure 6 The graph shows the temperature-furnace relative height relationship for crystal growth in this equipment. It can be seen that the slope of the curves is relatively high in both the high-temperature and low-temperature sections, and the transition in the middle section is stable, which meets the temperature field requirements for large-size crystal growth.

[0065] Comparative Example 1

[0066] Cerium-doped lanthanum bromide (LaBr3:Ce) crystals and cesium iodide (CsI) crystals were grown simultaneously in a single furnace.

[0067] The constructed growth equipment mainly consists of a furnace body, a temperature control unit, and a drive unit. The furnace body has a circular cross-section and three temperature zones from top to bottom. Each temperature zone corresponds to a heating module, for a total of three heating modules. Each heating module is circular, and the heating wire is a Kanthal resistance wire, embedded and wrapped inside the module. The outer diameter of the heating module is 30cm and the inner diameter is 14cm. The height of the first heating module is 25cm, and the height of the second and third heating modules is 20cm. A single-layer heat insulation plate is installed between the first and second heating modules and between the second and third heating modules. The single-layer heat insulation plate has an outer diameter of 30cm, an inner diameter of 10cm, and a thickness of 11cm. The temperature control unit consists of three temperature controllers, each controlling one heating module. The drive unit is connected to the downpipe inside the furnace body and can automatically raise and lower. The rapid raising and lowering speed can reach 40cm / min, and the slow raising and lowering speed can reach 0.01mm / h.

[0068] 4.87g of anhydrous cerium bromide (99.99% purity) and 92.65g of anhydrous lanthanum bromide (99.99% purity) were mixed and stirred evenly in a glove box, and then placed into a quartz crucible with a pointed cone. The inner diameter of the equal-diameter section of the quartz crucible was 25mm and the height was 80mm. After the raw materials were placed in, the quartz crucible was removed from the glove box and immediately connected to a vacuum pump for vacuum sealing. 84.78g of anhydrous cesium iodide (99.99% purity) was placed into a quartz crucible with a pointed cone in the glove box. The inner diameter of the equal-diameter section of the quartz crucible was 25mm and the height was 80mm. After the quartz crucible was removed from the glove box, it was vacuum sealed.

[0069] The two crucibles were placed in the same alumina down-feed tube. The down-feed tube had an outer diameter of 8 cm, a wall thickness of 5 mm, and a height of 100 cm. The crucible doped with cerium and lanthanum bromide was placed in the upper part of the down-feed tube, and the crucible doped with cesium iodide was placed in the lower part of the down-feed tube. The remaining part of the down-feed tube was filled with ZrO2 powder. The bottoms of the two crucibles were 31 cm apart, and thermocouples were placed at the bottom of the crucibles respectively.

[0070] The lead tube obtained in the above steps is placed in a stainless steel disc. This disc is connected to a mechanical device that can automatically raise and lower the lead tube. The disc is then automatically raised and adjusted so that the bottom of the cesium iodide crucible is flush with the bottom of the second heating module. The thermocouples at the bottom of the two crucibles are connected to a thermometer, and the furnace is sealed. The three heating modules are then heated to 860°C, 710°C, and 370°C, respectively. At this point, the thermocouple temperature at the bottom of the cerium-doped lanthanum bromide crucible is 784°C, and the thermocouple temperature at the bottom of the cesium iodide crucible is 625°C. The disc height is then raised by 5 cm. After 6 hours, the disc height is lowered by 5 cm. After 6 hours, the disc is slowly lowered at a rate of 1 mm / h. After 80 hours, the lowering is stopped. The temperature of each of the three heating modules is reduced to room temperature at a rate of 15°C / h. Then, the crucible and crystal are removed sequentially.

[0071] The method steps of Comparative Example 1 and Example 1 are the same, the difference being that the equipment in Comparative Example 1 uses a single-layer heat insulation board with a straight through hole in the middle, while the double-layer heat insulation board in Example 1 forms an opening that is smaller at the top and larger at the bottom. Figure 7 The cerium-doped lanthanum bromide crystal obtained in Comparative Example 1 shows numerous impurities and defects, including many cracks. Figure 8 The graph shows the relationship between temperature and relative height of the furnace body during crystal growth. It can be seen that although the slope of the curve is high in the high-temperature section, the slope of the curve is very low in the low-temperature section, which is basically the same as that in the middle section. Therefore, it will seriously affect crystal growth.

[0072] Example 2

[0073] Cerium-doped lanthanum bromide (LaBr3:Ce) crystals and cesium iodide (CsI) crystals were grown simultaneously in a single furnace.

[0074] The constructed growth equipment mainly consists of a furnace body, a temperature control unit, and a drive unit. The furnace body has a circular cross-section and three temperature zones from top to bottom, each corresponding to a heating module. There are three heating modules in total, each circular, with Kanthal resistance wire embedded and wrapped inside the module. The outer diameter of each heating module is 40cm and the inner diameter is 24cm. The first heating module is 25cm high, and the second and third heating modules are 20cm high. Double-layer heat insulation plates are installed between the first and second heating modules, as well as between the second and third heating modules. The upper heat insulation plate has an outer diameter of 40cm, an inner diameter of 12cm, and a thickness of 6cm, while the lower heat insulation plate has an outer diameter of 40cm, an inner diameter of 18cm, and a thickness of 6cm. The furnace body is surrounded by a circular shell. The temperature control unit consists of three temperature controllers, each controlling one heating module. The drive unit is connected to the downpipe inside the furnace body and can automatically raise and lower the furnace. The rapid raising and lowering speed can reach 40cm / min, and the slow raising and lowering speed can reach 0.001mm / h.

[0075] 17.12g of anhydrous cerium bromide (99.99% purity) and 325.32g of anhydrous lanthanum bromide (99.99% purity) were mixed and stirred evenly in a glove box, and then placed into a quartz crucible with a pointed cone. The inner diameter of the equal-diameter section of the quartz crucible was 38mm and the height was 120mm. After the raw materials were placed in, the quartz crucible was removed from the glove box and immediately connected to a vacuum pump for vacuum sealing. 704.56g of anhydrous cesium iodide (99.99% purity) was placed into a quartz crucible with a pointed cone in the glove box. The inner diameter of the equal-diameter section of the quartz crucible was 51mm and the height was 150mm. After the quartz crucible was removed from the glove box, it was vacuum sealed.

[0076] The two crucibles were placed in the same alumina down-feed tube, which had an outer diameter of 10 cm, a wall thickness of 6 mm, and a height of 100 cm. The crucible doped with cerium and lanthanum bromide was placed in the upper part of the down-feed tube, and the crucible doped with cesium iodide was placed in the lower part of the down-feed tube. The remaining part of the down-feed tube was filled with ZrO2 powder. The bottoms of the two crucibles were 38 cm apart, and thermocouples were placed at the bottom of the crucibles respectively.

[0077] The lead tube obtained in the above steps is placed in a stainless steel disc. This disc is connected to a mechanical device that can automatically raise and lower the lead tube. The disc is then automatically raised and adjusted so that the bottom of the cesium iodide crucible is flush with the bottom of the second heating module. The thermocouples at the bottom of the two crucibles are connected to a thermometer, and the furnace is sealed. The three heating modules are then heated to 870°C, 721°C, and 380°C, respectively. At this point, the thermocouple temperature at the bottom of the cerium-doped lanthanum bromide crucible is 784°C, and the thermocouple temperature at the bottom of the cesium iodide crucible is 623°C. The disc height is then raised by 5 cm. After 6 hours, the disc height is lowered by 5 cm. After 6 hours, the disc is slowly lowered at a rate of 0.5 mm / h. After 180 hours, the lowering is stopped. The temperature of all three heating modules is reduced to room temperature at a rate of 10°C / h. Then, the crucibles and crystals are removed sequentially.

[0078] The crystal structure obtained in Example 2 is similar to that in Example 1, and has a higher quality.

[0079] Example 3

[0080] Lead tungstate (PbWO4), LaBr3:Ce, and CsI crystals were grown simultaneously in a single furnace.

[0081] The constructed growth equipment mainly consists of a furnace body, a temperature control unit, and a drive unit. The furnace body has a rectangular cross-section and four temperature zones from top to bottom. The heating element for the first temperature zone is a silicon molybdenum rod, while the heating elements for the second, third, and fourth temperature zones are Kanthal resistance wires. The center-to-center spacing between adjacent temperature zones is 30cm. Each temperature zone is separated by a double-layer insulation board. The insulation board between the first and second temperature zones is a hollow double-layer alumina refractory brick, with both layers being 4cm thick, the upper layer having a center width of 12cm, and the lower layer having a center width of 18cm. The insulation boards between the second and third temperature zones, and between the third and fourth temperature zones... The insulation panels between the zones are double-layered alumina fiber bricks, both layers being 4cm thick, with the upper layer having a center width of 12cm and the lower layer having a center width of 18cm. The temperature control unit consists of four temperature controllers, each controlling the temperature of one zone. The first zone has a transformer, which is controlled by the temperature controllers. The transformer is connected to a silicon molybdenum rod. The temperature controllers for the second, third, and fourth zones are directly connected to resistance wires. The drive unit has a rectangular aluminum platform, which is connected to the mechanical system. This platform enables the lowering device to automatically lift and lower. The rapid lifting and lowering speed can reach 30cm / min, and the slow lifting and lowering speed can reach 0.01mm / h.

[0082] Lead oxide (PbO) and tungsten oxide (WO3), both with a purity of 99.99%, were weighed and mixed in a 1:1 molar ratio. After stirring evenly, the mixture was sintered in solid state at 400°C for 20 hours to obtain polycrystalline lead tungstate (PbWO4). 191.52 g, 192.06 g, and 191.85 g of PbWO4 polycrystalline material were respectively placed into three platinum crucibles. Additionally, 17.56 g of anhydrous cerium bromide and 332.92 g of anhydrous lanthanum bromide raw materials, 17.03 g of anhydrous cerium bromide and 323.76 g of anhydrous lanthanum bromide raw materials, and 17.81 g of anhydrous cerium bromide and 339.02 g of anhydrous lanthanum bromide raw materials, all with a purity of 99.99%, were also prepared. Lanthanum oxide raw materials were mixed and stirred evenly in a glove box, and then separately loaded into three quartz crucibles with pointed cones. The inner diameter of the equal-diameter section of each quartz crucible was 38 mm, and the height was 120 mm. After loading the raw materials, the quartz crucibles were removed from the glove box and immediately connected to a vacuum pump for vacuum sealing. Anhydrous cesium iodide raw materials with a purity of 99.99% were loaded into three quartz crucibles with pointed cones. The inner diameter of the equal-diameter section of each quartz crucible was 51 mm, and the height was 150 mm. The raw material amounts in the crucibles were 702.28 g, 701.83 g, and 702.80 g, respectively. After removing the quartz crucibles from the glove box, they were vacuum sealed.

[0083] The crucibles obtained in the above steps were placed into three alumina down-feed tubes. The alumina down-feed tubes had an outer diameter of 10 cm, a wall thickness of 6 mm, and a height of 120 cm. In each alumina down-feed tube, from top to bottom, were placed a platinum crucible containing PbWO4, a quartz crucible containing LaBr3:Ce, and a quartz crucible containing CsI. The bottoms of the platinum crucible containing PbWO4 and the quartz crucible containing LaBr3:Ce were 38 cm apart, as were the bottoms of the quartz crucible containing LaBr3:Ce and the quartz crucible containing CsI. The remaining part of the down-feed tube was tightly filled with ZrO2 powder.

[0084] Then, three alumina downpipes were placed parallel to each other on a rectangular aluminum platform, and thermocouples were placed at the bottom of the crucible. The height of the rectangular platform was adjusted by the drive unit so that the bottom of the lead tungstate crucible was at the same height as the bottom of the first temperature zone. The thermocouples at the bottom of the crucible were connected to a thermometer, and the furnace was sealed. The four temperature zones were then heated to 1190°C, 850°C, 715°C, and 370°C, respectively. At this point, the temperature of the thermocouple at the bottom of the lead tungstate crucible was 1125°C. (The last sentence appears to be incomplete and possibly refers to lanthanum bromide doped with cerium.) The temperature of the thermocouple at the bottom of the crucible was 784°C, and the temperature of the thermocouple at the bottom of the cesium iodide crucible was 623°C. Then the aluminum platform was raised by 3cm, and after 6 hours it was lowered by 3cm. After 8 hours it began to descend slowly at a rate of 0.5mm / h. After 200 hours it stopped descending. The temperature of the uppermost temperature zone was lowered to 300°C at a rate of 12°C / h. Then the heating of the temperature zone was turned off. The temperature of the other temperature zones was lowered to room temperature at a rate of 12°C / h. Then the crucible and the crystal were taken out in sequence.

[0085] The crystal structure obtained in Example 3 is similar to that in Example 1, and has a higher quality.

[0086] Example 4

[0087] PbWO4 crystals, lead fluoride (PbF2) crystals, and cesium iodide (CsI) crystals are grown simultaneously in a single furnace.

[0088] The constructed growth equipment mainly consists of a furnace body, a temperature control unit, and a drive unit. The furnace body has a rectangular cross-section and four temperature zones from top to bottom. The heating element for the first temperature zone is a silicon molybdenum rod, while the heating elements for the second, third, and fourth temperature zones are Kanthal resistance wires. The center-to-center spacing between adjacent temperature zones is 30cm. Each temperature zone is separated by a double-layer insulation board. The insulation board between the first and second temperature zones is a hollow double-layer alumina refractory brick, with both layers being 4cm thick, the upper layer having a center-to-center width of 12cm, and the lower layer having a center-to-center width of 18cm. The insulation boards between the second and third temperature zones, and between the third and fourth temperature zones... The insulation board between the temperature zones is a double-layer alumina fiber brick, with both layers being 4cm thick. The upper layer has a center width of 12cm, and the lower layer has a center width of 18cm. The temperature control unit consists of four temperature controllers, each controlling the temperature of one temperature zone. The first temperature zone has a transformer, which is controlled by the temperature controller. The transformer is connected to a silicon molybdenum rod. The temperature controllers for the second, third, and fourth temperature zones are directly connected to resistance wires. The drive unit has a rectangular aluminum platform. The mechanical system is connected to this platform, enabling it to drive the lowering device to automatically lift and lower. The rapid lifting and lowering speed can reach 30cm / min, and the slow lifting and lowering speed can reach 0.01mm / h.

[0089] Lead oxide (PbO) and tungsten oxide (WO3), both with a purity of 99.99%, were weighed and mixed in a 1:1 molar ratio. After stirring evenly, the mixture was sintered in solid state at 400°C for 20 hours to obtain polycrystalline PbWO4. 182.76 g, 180.92 g, 181.54 g, and 181.93 g of PbWO4 polycrystalline material were respectively placed into four platinum crucibles; 211.27 g, 210.82 g, 211.75 g, and 2... (The sentence is incomplete in the original text.) 10.24g of PbF2 raw material was placed into four platinum crucibles, and then the platinum crucibles were mechanically sealed. Anhydrous cesium iodide raw material with a purity of 99.99% was placed into four quartz crucibles with pointed cones. The inner diameter of the equal-diameter section of the quartz crucibles was 38mm and the height was 120mm. The raw material amounts in the crucibles were 265.72g, 266.81g, 265.87g, and 266.17g, respectively. After the quartz crucibles were removed from the glove box, they were vacuum sealed.

[0090] The crucibles obtained in the above steps were placed into four alumina down-feed tubes. The alumina down-feed tubes had an outer diameter of 10 cm, a wall thickness of 6 mm, and a height of 120 cm. In each alumina down-feed tube, from top to bottom, were placed a platinum crucible containing PbWO4, a platinum crucible containing PbF2, and a quartz crucible containing CsI. The bottoms of the platinum crucible containing PbWO4 and the quartz crucible containing PbF2 were 38 cm apart, as were the bottoms of the quartz crucible containing PbF2 and the quartz crucible containing CsI. The remaining part of the down-feed tube was tightly filled with ZrO2 powder.

[0091] Then, four alumina down-lead tubes are placed parallel to each other on the rectangular aluminum platform of the drive unit, and then thermocouples are placed at the bottom of the crucible, with a structure as follows: Figure 3 As shown; the height of the rectangular platform was adjusted using a mechanical system so that the bottom of the lead tungstate (PbWO4) crucible was at the same height as the bottom of the first temperature zone. The thermocouple at the bottom of the crucible was connected to a thermometer, and the furnace was sealed. The four temperature zones were then heated to 1190°C, 893°C, 716°C, and 372°C respectively. At this point, the thermocouple temperature at the bottom of the PbWO4 crucible was 1128°C, and the thermocouple temperature at the bottom of the PbF2 crucible was 832°C. The temperature of the thermocouple at the bottom of the C,CsI crucible was 624°C. The aluminum platform was then raised by 30 mm. After 6 hours, the aluminum platform was lowered by 28 mm. After 8 hours, the platform was lowered slowly at a rate of 0.6 mm / h. After 240 hours, the lowering was stopped. The temperature of the uppermost temperature zone was lowered to 300°C at a rate of 15°C / h. Then, the heating of the temperature zone was turned off. The temperature of the remaining temperature zones was lowered to room temperature at a rate of 15°C / h. Finally, the crucible and crystal were removed in sequence.

[0092] The crystal structure obtained in Example 4 is similar to that in Example 1, and has a higher quality.

[0093] Example 5

[0094] PbWO4 crystals, cesium fluoride (CsF) crystals, and cesium copper iodide (Cs3Cu2I5) crystals were grown simultaneously in a single furnace.

[0095] The constructed growth equipment mainly consists of a furnace body, a temperature control unit, and a drive unit. The furnace body has a rectangular cross-section and four temperature zones from top to bottom. The heating element for the first temperature zone is a silicon molybdenum rod, while the heating elements for the second, third, and fourth temperature zones are Kanthal resistance wires. The height interval between the first and second temperature zones is 40cm, and the height intervals between the second and third, and between the third and fourth temperature zones are all 30cm. Each temperature zone is separated by a double-layer insulation board. The insulation board between the first and second temperature zones is a hollow double-layer alumina refractory brick, with both layers being 4cm thick, the upper layer having a center width of 12cm, and the lower layer having a center width of 18cm. The insulation board between the second and fourth temperature zones... The insulation panels between the third and fourth temperature zones are double-layered alumina fiber bricks, each 4cm thick, with the upper layer having a center width of 12cm and the lower layer a center width of 18cm. The temperature control unit consists of four temperature controllers, each controlling the temperature of one zone. The first zone has a transformer, which is controlled by the temperature controllers. The transformer is connected to a silicon molybdenum rod. The temperature controllers for the second, third, and fourth zones are directly connected to resistance wires. The drive unit has a rectangular aluminum platform connected to the mechanical system, enabling the platform to drive the lowering device for automatic lifting and lowering. The rapid lifting and lowering speed can reach 30cm / min, and the slow lifting and lowering speed can reach 0.01mm / h.

[0096] Lead oxide (PbO) and tungsten oxide (WO3), both with a purity of 99.99%, were weighed and mixed in a 1:1 molar ratio. After stirring evenly, the mixture was sintered in solid state at 400°C for 20 hours to obtain PbWO4 polycrystalline material. 182.76 g, 180.92 g, and 181.54 g of PbWO4 polycrystalline material were respectively placed into three platinum crucibles. Similarly, 120.21 g, 121.82 g, and 120.79 g of CsF raw material with a purity of 99.99% were respectively placed into three platinum crucibles. The platinum crucible was then mechanically sealed. Anhydrous cesium iodide (CsI) and anhydrous cuprous iodide (CuI) raw materials with a purity of 99.99% were weighed and mixed evenly in a glove box at a molar ratio of 3:2. Then, 85.02g, 85.27g, and 84.86g of the mixture were respectively loaded into three quartz crucibles with pointed cones. The inner diameter of the equal-diameter part of the quartz crucible was 38mm and the height was 120mm. After the quartz crucibles were removed from the glove box, they were vacuum sealed.

[0097] The crucibles obtained in the above steps were placed into three alumina down-feed tubes. The alumina down-feed tubes had an outer diameter of 10 cm, a wall thickness of 6 mm, and a height of 120 cm. In each alumina down-feed tube, from top to bottom, were placed a platinum crucible containing PbWO4, a platinum crucible containing CsF, and a quartz crucible containing Cs3Cu2I5. The bottoms of the platinum crucible containing PbWO4 and the quartz crucible containing CsF were 48 cm apart, and the bottoms of the quartz crucible containing PbF2 and the quartz crucible containing CsI were 38 cm apart. The remaining part of the down-feed tube was tightly filled with ZrO2 powder.

[0098] Then, three alumina lead-down tubes were placed parallel to each other on the rectangular aluminum platform of the drive unit. A thermocouple was placed at the bottom of the middle crucible in each layer. The height of the lead-down device was adjusted mechanically so that the bottom of the PbWO4 crucible was at the same height as the bottom of the first temperature zone. The thermocouple at the bottom of the crucible was connected to a thermometer, and the furnace was sealed. The four temperature zones were then heated to 1187°C, 724°C, 419°C, and 212°C respectively. At this point, the temperature of the thermocouple at the bottom of the PbWO4 crucible was 1124°C. The temperature of the thermocouple at the bottom of the sF crucible was 685°C, and the temperature of the thermocouple at the bottom of the Cs3Cu2I5 crucible was 385°C. Then the aluminum platform was raised by 20 mm, and after 6 hours it was lowered by 18 mm. After 8 hours it began to descend slowly at a rate of 0.6 mm / h. After 240 hours it stopped descending. The temperature of the uppermost temperature zone was lowered to 300°C at a rate of 15°C / h. Then the heating of the temperature zone was turned off. The temperature of the remaining temperature zones was lowered to room temperature at a rate of 15°C / h. Then the crucible and the crystal were taken out in sequence.

[0099] The crystal structure obtained in Example 5 is similar to that in Example 1, and has a higher quality.

[0100] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0101] Furthermore, given that details have been set forth to describe exemplary embodiments of this application, it will be apparent to those skilled in the art that embodiments of this application may be practiced without these details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0102] Although this application has been described in conjunction with embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0103] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. An apparatus for growing multiple crystals in a single furnace, characterized in that, include: The furnace body has at least three temperature zones inside from top to bottom, with the temperature zone near the top of the furnace body having a higher temperature than the temperature zone near the bottom of the furnace body. A temperature control unit is installed in each of the temperature zones to control the temperature of the temperature zones; A heat insulation layer is disposed between two adjacent temperature zones. The heat insulation layer has an opening in the middle. The orthographic projection of the side of the opening near the top of the furnace body on the horizontal plane is a first projection. The orthographic projection of the side of the opening near the bottom of the furnace body on the horizontal plane is a second projection. The second projection covers the first projection. A down-draft tube is located inside the furnace body and is arranged to pass through the openings of each of the heat insulation layers in sequence. At least two crucibles are arranged inside the down-draft tube from top to bottom. Each crucible is used to hold a raw material of a crystal and is arranged in a corresponding temperature zone. The space between the down-draft tube and the crucible is filled with heat insulation material. The thermal conductivity of the heat insulation material decreases as the temperature decreases. A drive unit, connected to the down-lead tube, is used to drive the down-lead tube to move up and down.

2. The apparatus for growing multiple crystals in a single furnace according to claim 1, characterized in that, The heat insulation layer includes a first heat insulation plate and a second heat insulation plate stacked together. The first heat insulation plate has a first through hole in the middle, and the second heat insulation plate has a second through hole in the middle. The size of the second through hole is larger than the size of the first through hole, and the first through hole and the second through hole form the opening.

3. The apparatus for growing multiple crystals in a single furnace according to claim 1, characterized in that, At least one of the insulation layers near the top of the furnace body is a hollow alumina refractory brick, and the remaining insulation layers are alumina fiber bricks.

4. The apparatus for growing multiple crystals in a single furnace according to claim 1, characterized in that, The insulation material is zirconium oxide powder.

5. The apparatus for growing multiple crystals in a single furnace according to claim 1, characterized in that, The drive unit is a lifting platform, and the temperature control unit includes a temperature controller and a heating module.

6. The apparatus for growing multiple crystals in a single furnace according to claim 1, characterized in that, The temperature difference between adjacent temperature zones near the top of the furnace body is greater than or equal to 100°C, and the temperature difference between adjacent temperature zones near the bottom of the furnace body is less than or equal to 50°C.

7. The apparatus for growing multiple crystals in a single furnace according to claim 1, characterized in that, The drive unit drives the lower tube to rise and fall at a speed of 0.01 mm / h to 40 cm / min.

8. A method for growing multiple crystals in a single furnace, characterized in that, Using the apparatus for growing multiple crystals in a single furnace as described in any one of claims 1-7, the method for growing multiple crystals in a single furnace comprises: The drive unit drives the down tube to rise, and different crystal raw materials are placed in crucibles at different heights in the down tube; The driving unit drives the down tube to descend, so that the bottom of the crucible is flush with the top of the opening of the heat insulation layer, and the temperature control unit raises the temperature of the temperature zone to above the melting point of the corresponding crystal growth. The drive unit drives the down tube to rise a preset distance to melt the material. After a first preset time, the drive unit drives the down tube to fall a preset distance to keep it warm. After the heat preservation period has been completed for a second preset time, the drive unit drives the lead tube to descend at a preset speed to perform crystal growth. After growth is complete, the temperature of the temperature zone is reduced by the temperature control unit, and the guide tube is driven to rise by the drive unit to remove the crucible and obtain various crystals.

9. The method for growing multiple crystals in a single furnace according to claim 8, characterized in that, The preset distance is 4cm to 5cm, the first preset time is 4h to 10h, the second preset time is 5h to 10h, and the preset speed is 0.2mm / h to 2mm / h.

10. The method for growing multiple crystals in a single furnace according to claim 8, characterized in that, The step of reducing the temperature of the temperature zone by means of the temperature control unit includes: reducing the temperature of the temperature zone to room temperature by means of the temperature control unit at a rate of 10°C / h to 15°C / h.

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