Czochralski method crystal growth device and regulation and control method

Abstract

The embodiment of the invention provides a Czochralski method crystal growth device and a regulation and control method, and relates to the technical field of crystal growth. The Czochralski method crystal growth device comprises a furnace body, a crucible, a first magnetic field device, a seed rod and a second magnetic field device, the crucible is arranged in the furnace body, and the first magnetic field device is arranged on the outer side of the crucible in a surrounding mode and located in the furnace body. The seed rod is arranged in the furnace body and is spaced from the crucible; the second magnetic field device is arranged on the seed crystal rod and is positioned in the furnace body; wherein the first magnetic field device is used for generating a magnetic field and acting on a melt in the crucible; the second magnetic field device is used for generating a magnetic field and acting on a growth interface of the melt. The Czochralski method crystal growth device can effectively inhibit convection of melt, so that solute distribution is uniform, and crystal defects are reduced; and the crystal structure can be optimized, and accurate regulation and control of solute are realized, so that the quality and the performance of the crystal are integrally improved.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal growth, and in particular to a Czochralski crystal growth device and a control method. Background Art

[0002] The Czochralski method, also known as the Czochralski method, is a traditional single crystal growth method for preparing large-size, high-quality single crystals from the melt. The crystal growth process includes melting, seeding, shouldering, equal diameter, and finishing. Common crystals such as silicon single crystals, germanium single crystals, lithium niobate, lithium tantalate, gallium oxide, sapphire, etc. are usually grown by the Czochralski method.

[0003] However, when preparing crystals by the traditional Czochralski method, the distribution of solutes is often uneven due to factors such as natural convection and thermal convection of the melt, resulting in stress, defects and other problems inside the crystal. In addition, the microstructure of the crystal during the growth process is difficult to accurately control, which is not conducive to maintaining composition consistency and structural integrity, resulting in poor overall quality and performance of the crystal. Summary of the invention

[0004] The object of the present invention is to provide a Czochralski crystal growth device and a control method, which can effectively suppress the convection of the melt, make the solute evenly distributed, and reduce crystal defects; and can optimize the crystal structure and achieve precise control of the solute, thereby improving the quality and performance of the crystal as a whole.

[0005] The embodiment of the present invention is achieved as follows:

[0006] In a first aspect, the present invention provides a Czochralski crystal growth device, comprising:

[0007] Furnace body;

[0008] A crucible, wherein the crucible is disposed in the furnace body;

[0009] A first magnetic field device, which is disposed around the outside of the crucible and is located in the furnace body;

[0010] A seed crystal rod, the seed crystal rod is disposed in the furnace body and spaced apart from the crucible; and

[0011] a second magnetic field device, the second magnetic field device being disposed on the seed crystal rod and located inside the furnace body;

[0012] The first magnetic field device is used to generate a magnetic field and act on the melt in the crucible; the second magnetic field device is used to generate a magnetic field and act on the growth interface of the melt.

[0013] In an optional embodiment, the second magnetic field device includes a solenoid coil and a fixed sleeve, the fixed sleeve is sleeved on one end of the seed rod close to the crucible, and the solenoid coil is sleeved on the fixed sleeve.

[0014] In an optional embodiment, an outer side wall of the fixing sleeve is provided with a first spiral groove, and the spiral tube coil is arranged in the first spiral groove.

[0015] In an optional embodiment, the second magnetic field device further includes a power line and a signal line, the power line and the signal line are both sleeved on the seed rod, and the power line and the signal line are both connected to the solenoid coil.

[0016] In an optional embodiment, the outer side wall of the seed rod is provided with a second spiral groove, and the power line is arranged in the second spiral groove; and / or,

[0017] The outer wall of the seed rod is provided with a third spiral groove, and the signal line is arranged in the third spiral groove.

[0018] In an optional embodiment, the distance between the bottom of the second magnetic field device and the top of the crucible is 1 cm to 10 cm.

[0019] In an optional embodiment, the magnetic field strength produced by the second magnetic field device is 100 Gs to 1000 Gs.

[0020] In an optional embodiment, the Czochralski crystal growth device further includes a heat-insulating cover, which is disposed in the furnace body and covers the opening of the crucible to form a crystal growth chamber between the heat-insulating cover and the crucible;

[0021] Wherein, the seed crystal rod is inserted into the heat-insulating cover, and at least a part of the seed crystal rod is located in the crystal growth chamber, and the second magnetic field device is located in the crystal growth chamber.

[0022] In an optional embodiment, the Czochralski crystal growth device further includes a heat-insulating barrel, wherein the heat-insulating barrel is located in the furnace body, the crucible is disposed in the heat-insulating barrel, and the first magnetic field device is disposed around the outside of the heat-insulating barrel.

[0023] In an optional embodiment, the Czochralski crystal growth device further comprises a particle insulation layer, wherein the particle insulation layer is wrapped around the outer wall of the crucible and is disposed in the insulation barrel.

[0024] In a second aspect, the present invention provides a method for regulating crystal growth by a CZ method, which is implemented using the CZ method crystal growth device described in any one of the aforementioned embodiments, and the method for regulating crystal growth by a CZ method comprises:

[0025] Starting the first magnetic field device to apply a magnetic field to the melt in the crucible;

[0026] The second magnetic field device is started to apply a magnetic field to the growth interface of the melt.

[0027] In an optional embodiment, the step of starting the first magnetic field device to apply a magnetic field to the melt in the crucible includes:

[0028] During the melting stage of the polycrystalline material of the crystal, the first magnetic field device is started to apply a magnetic field of a first magnetic field strength to the polycrystalline material to obtain the melt;

[0029] In the shoulder release stage of the crystal, the first magnetic field device is started, and a magnetic field with a gradually increasing magnetic field strength is applied to the melt on the basis of the first magnetic field strength, until the magnetic field strength at the end of the shoulder release is the second magnetic field strength;

[0030] At the stage of equal diameter of the crystal, starting the first magnetic field device to apply the magnetic field of the second magnetic field strength to the melt;

[0031] At the end of the crystal formation, the first magnetic field device is started to apply a magnetic field of a third magnetic field strength to the melt;

[0032] The first magnetic field strength is smaller than the second magnetic field strength, and the second magnetic field strength is larger than the third magnetic field strength.

[0033] In an optional embodiment, the step of starting the second magnetic field device to apply a magnetic field to the growth interface of the melt includes:

[0034] In the seed crystal seeding stage, the second magnetic field device is started to apply a magnetic field of a fourth magnetic field strength to the growth interface of the melt, and the direction of the magnetic field is a direction away from the growth interface;

[0035] During the crystal growth stage, the second magnetic field device is started to apply a magnetic field of a fifth magnetic field strength to the growth interface of the melt, and the direction of the magnetic field is close to the growth interface;

[0036] The fourth magnetic field strength is smaller than the fifth magnetic field strength, and the growth stage includes a shoulder release stage, an equal diameter stage and a finishing stage.

[0037] The beneficial effects of the embodiments of the present invention include:

[0038] The Czochralski crystal growth device comprises a furnace body, a crucible, a first magnetic field device, a seed crystal rod and a second magnetic field device; the crucible is arranged in the furnace body, the first magnetic field device is arranged around the outside of the crucible and is located in the furnace body; the seed crystal rod is arranged in the furnace body and is spaced apart from the crucible; the second magnetic field device is arranged on the seed crystal rod and is located in the furnace body; wherein the first magnetic field device is used to generate a magnetic field and act on the melt in the crucible; the second magnetic field device is used to generate a magnetic field and act on the growth interface of the melt.

[0039] The first magnetic field device is used to macro-control the crystal growth. Specifically, different magnetic fields can be applied at different growth stages of the crystal. The magnetic field can generate Lorentz force on the charged particles in the melt, affecting the convection state of the melt, such as affecting the natural convection of the melt, thereby effectively inhibiting the convection of the melt, making the solute distribution uniform, and making the temperature distribution in the melt more uniform, reducing the crystal growth defects caused by the temperature gradient. At the same time, the second magnetic field device is used to micro-control the crystal growth. Specifically, different magnetic fields can be applied at different growth stages of the crystal, which can act on the growth interface of the crystal. The magnetic field will change the energy field near the seed crystal, affect the nucleation process of the crystal, and promote the crystal to grow more orderly; and accurately control the distribution of solutes on a microscopic scale to meet the requirements of the crystal for specific properties, and can achieve precise control of the doping concentration, thereby optimizing the microstructure of the crystal and improving the stability of the crystal.

[0040] That is to say, through the coordinated cooperation of the first magnetic field device and the second magnetic field device, the growth process of the crystal can be optimized at both the macro and micro levels, reducing various defects of the crystal, thereby improving the quality and performance of the crystal as a whole.

[0041] The Czochralski crystal growth control method is implemented by using a Czochralski crystal growth device, which includes: starting a first magnetic field device and applying a magnetic field to the melt in the crucible; starting a second magnetic field device and applying a magnetic field to the growth interface of the melt. The Czochralski crystal growth control method can work in coordination by simultaneously setting magnetic field devices around the crucible and near the crystal growth interface. A stable macroscopic environment is provided around the crucible to suppress the overall convection of the melt and the macroscopic inhomogeneity of the solute, and the magnetic field at the growth interface optimizes the crystal growth process at the microscopic level; the crystal growth process can be jointly optimized at both the macroscopic and microscopic levels, the crystal growth interface is stabilized, various defects of the crystal are reduced, and the microscopic structure of the crystal is optimized, thereby improving the quality and performance of the crystal as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 A schematic diagram of the structure of a Czochralski crystal growth device provided in an embodiment of the present invention;

[0044] Figure 2 A flowchart of a method for controlling crystal growth by a Czochralski method provided in an embodiment of the present invention;

[0045] Figure 3 for Figure 2 Flow chart of the sub-steps of step S10;

[0046] Figure 4 for Figure 2 Flow chart of the sub-steps of step S20;

[0047] Figure 5 for Figure 4 Schematic diagram of magnetic field direction in neutron step S21;

[0048] Figure 6 for Figure 4 Schematic diagram of magnetic field direction in neutron step S22.

[0049] Icons: 100-crystal growth device using the Czochralski method; 10-furnace body; 20-crucible; 30-first magnetic field device; 40-seed crystal rod; 50-second magnetic field device; 51-spiral tube coil; 52-fixed sleeve; 521-first spiral groove; 53-power line; 54-signal line; 60-insulation cover; 70-insulation barrel; 80-granular insulation layer; 200-melt; 300-crystal; 310-crystal surface; 400-seed crystal. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0053] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0054] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0055] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] As described in the background technology, when preparing crystals by the traditional pulling method, the distribution of solutes is often uneven due to factors such as natural convection and thermal convection of the melt, resulting in stress, defects and other problems inside the crystal. In addition, the microstructure of the crystal during the growth process is difficult to accurately control, which is not conducive to maintaining composition consistency and structural integrity, resulting in poor overall quality and performance of the crystal.

[0057] Based on this, please refer to Figure 1-Figure 6The embodiment of the present invention provides a CZ crystal growth device 100 and a control method, which can effectively improve the above-mentioned technical problems, that is, it can effectively suppress the convection of the melt 200, make the solute distribution uniform, and reduce the defects of the crystal 300; and it can optimize the structure of the crystal 300, realize the precise control of the solute, thereby improving the quality and performance of the crystal 300 as a whole. The CZ crystal growth device 100 and the control method will be described in detail below.

[0058] Please refer to Figure 1 , Figure 1 The structure diagram of the Czochralski crystal growth device 100 provided in this embodiment is shown in FIG. Figure 1 The Czochralski crystal growth device 100 includes a furnace body 10, a crucible 20, a first magnetic field device 30, a seed rod 40 and a second magnetic field device 50; the crucible 20 is arranged in the furnace body 10, the first magnetic field device 30 is arranged around the outside of the crucible 20 and is located in the furnace body 10; the seed rod 40 is arranged in the furnace body 10 and is spaced from the crucible 20; the second magnetic field device 50 is arranged on the seed rod 40 and is located in the furnace body 10; wherein the first magnetic field device 30 is used to generate a magnetic field and act on the melt 200 in the crucible 20; the second magnetic field device 50 is used to generate a magnetic field and act on the growth interface of the melt 200.

[0059] It should be pointed out that the first magnetic field device 30 is used to macro-control the growth of the crystal 300. Specifically, different magnetic fields can be applied at different growth stages of the crystal 300. The magnetic field can generate Lorentz force on the charged particles in the melt 200, affecting the convection state of the melt 200, such as affecting the natural convection of the melt 200, thereby effectively suppressing the convection of the melt 200, making the solute distribution uniform, and making the temperature distribution in the melt 200 more uniform, thereby reducing the growth defects of the crystal 300 caused by the temperature gradient.

[0060] At the same time, the second magnetic field device 50 is used to microscopically regulate the growth of the crystal 300. Specifically, different magnetic fields can be applied at different growth stages of the crystal 300, which can act on the growth interface of the crystal 300. The magnetic field will change the energy field near the seed crystal 400, affecting the nucleation process of the crystal 300, and promoting a more orderly growth of the crystal 300. It can also precisely regulate the distribution of solutes on a microscopic scale to meet the requirements of the crystal 300 for specific performance, and can achieve precise control of the doping concentration, thereby optimizing the microstructure of the crystal 300 and improving the stability of the crystal 300.

[0061] That is to say, through the coordinated cooperation of the first magnetic field device 30 and the second magnetic field device 50, the growth process of the crystal 300 can be jointly optimized at both the macro and micro levels, various defects of the crystal 300 can be reduced, thereby improving the quality and performance of the crystal 300 as a whole.

[0062] It should be noted that, in this embodiment, the first magnetic field device 30 may specifically include an induction heating coil, and a magnetic field is generated around the crucible 20 by energizing the induction heating coil; and different magnetic field sizes can be achieved by adjusting the power, thereby corresponding to different growth stages, so as to achieve macro-control of the growth of the crystal 300, and cooperate with the second magnetic field device 50 to improve the quality and performance of the growth of the crystal 300.

[0063] In addition, it should be noted that the growth interface of the crystal 300 refers to the boundary region between the crystal 300 and the melt 200 during the growth of the crystal 300. This interface is the core region of the growth of the crystal 300, and its fluctuation and morphology have an important influence on the quality of the crystal 300. Therefore, by applying magnetic fields of different sizes and directions to the growth interface at different stages of the growth of the crystal 300, the quality and performance of the growth of the crystal 300 can be improved.

[0064] Specifically, the second magnetic field device 50 includes a spiral tube coil 51 and a fixed sleeve 52, the fixed sleeve 52 is sleeved on one end of the seed crystal rod 40 close to the crucible 20, and the spiral tube coil 51 is sleeved on the fixed sleeve 52. It is easy to understand that the spiral tube coil 51 can be connected to an external power supply, and the direction and size of the current can be changed by the power supply to flexibly adjust the size and direction of the magnetic field to meet the different magnetic field requirements of different growth stages. At the same time, by setting the fixed sleeve 52, the spiral tube coil 51 can be conveniently fixed, and the stability of the magnetic field generated by the spiral tube coil 51 can be improved.

[0065] It should be noted that the material of the fixing sleeve 52 can be ceramic, which has the characteristics of chemical corrosion resistance, high temperature resistance, wear resistance, high strength, stability and good toughness, and can better meet the use environment of the crystal 300 growth.

[0066] In order to better fix the helical coil 51 and further enhance the stability of the magnetic field generated by the helical coil 51 , in this embodiment, the outer wall of the fixing sleeve 52 is provided with a first helical groove 521 , and the helical coil 51 is disposed in the first helical groove 521 .

[0067] Further, in order to facilitate the connection between the solenoid coil 51 and other devices such as an external power supply, the second magnetic field device 50 also includes a power line 53 and a signal line 54, both of which are sleeved on the seed crystal rod 40, and both of which are connected to the solenoid coil 51. It is easy to understand that the power line 53 is used to connect to the power supply, and the signal line 54 is used to transmit the control signal, ensuring that the line connection is firm and has good insulation performance, which can prevent leakage from affecting the growth of the crystal 300.

[0068] Furthermore, in order to accurately control the current output by the power supply, the Czochralski crystal growth device 100 further includes a controller (not shown), which is electrically connected to the power supply. It is understood that the controller can be a power supply controller based on a computer program, which can send corresponding instructions according to the growth stage of the crystal 300, thereby accurately controlling the power supply to change the magnitude and direction of the current.

[0069] Similarly, in order to better install the power line 53 and the signal line 54, in this embodiment, the outer wall of the seed rod 40 is provided with a second spiral groove and a third spiral groove (not shown in the figure), the power line 53 is arranged in the second spiral groove, and the signal line 54 is arranged in the third spiral groove.

[0070] It should be noted that the second spiral groove and the third spiral groove can be connected to form an integral spiral groove, and the power line 53 and the signal line 54 are both arranged in the spiral groove; of course, the second spiral groove and the third spiral groove can also be arranged at intervals, and the power line 53 and the signal line 54 are installed independently without affecting each other.

[0071] Optionally, the distance between the bottom of the second magnetic field device 50 and the top of the crucible 20 is 1 cm to 10 cm. Specifically, in this embodiment, the distance between the bottom of the spiral tube coil 51 and the top of the crucible 20 is 1 cm to 10 cm. For example, the distance between the two can be 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, etc. Within this range, the magnetic field generated by the second magnetic field device 50 has a better effect on the melt 200, that is, the quality and performance of the growth of the crystal 300 are better.

[0072] Optionally, the magnetic field strength produced by the second magnetic field device 50 is 100 Gs to 1000 Gs, for example, the magnetic field strength may be 100 Gs, 200 Gs, 300 Gs, 400 Gs, 500 Gs, 600 Gs, 700 Gs, 800 Gs, 900 Gs, 1000 Gs, etc. Within this range, the magnetic field generated by the second magnetic field device 50 has a better effect on the melt 200, that is, the quality and performance of the growth of the crystal 300 are better.

[0073] Please continue to combine Figure 1 The Czochralski crystal growth device 100 also includes a heat-insulating cover 60, which is arranged in the furnace body 10 and covers the opening of the crucible 20 to form a crystal 300 growth chamber between the crucible 20; wherein the seed crystal rod 40 passes through the heat-insulating cover 60, and at least part of the seed crystal rod 40 is located in the crystal 300 growth chamber, and the second magnetic field device 50 is located in the crystal 300 growth chamber.

[0074] By providing the heat preservation cover 60, a heat preservation effect can be achieved, so that the temperature stability can be ensured during the process of pulling and rotating the crystal 300, and the problem of crystal 300 growth defects caused by temperature gradient during the pulling process can be reduced, thereby improving the quality and performance of the crystal 300 growth.

[0075] Furthermore, the Czochralski crystal growth device 100 further includes a heat preservation barrel 70, the heat preservation barrel 70 is located in the furnace body 10, the crucible 20 is disposed in the heat preservation barrel 70, and the first magnetic field device 30 is disposed around the outer side of the heat preservation barrel 70. It is easy to understand that by providing the heat preservation barrel 70, the crucible 20 can be kept warm, and the heat loss of the melt 200 in the crucible 20 can be avoided, thereby ensuring the stable growth of the crystal 300.

[0076] On the basis of the above, the Czochralski crystal growth device 100 provided in this embodiment further includes a particle insulation layer 80 , which is wrapped around the outer wall of the crucible 20 and disposed in the insulation barrel 70 .

[0077] It should be noted that, firstly, the granular insulation layer 80 can further prevent the conduction of heat and reduce the path of heat loss; secondly, there may be local temperature unevenness inside the insulation barrel 70. The granular insulation layer 80 can be used to fill the gap between the inside of the insulation barrel 70 and the crucible 20 to make the temperature distribution more uniform, thereby fine-tuning the temperature field and compensating for the temperature distribution defects that may occur in the insulation barrel 70; in addition, the granular insulation layer 80 has a buffering effect. During the operation of the growth device, tiny displacements or vibrations may occur due to factors such as thermal expansion. The granular insulation layer 80 can buffer these influences and avoid major interference with the growth environment of the crystal 300, thereby further improving the quality and performance of the growth of the crystal 300.

[0078] Please refer to Figure 2 , Figure 2 The flowchart of the method for controlling the growth of a crystal by the Czochralski method provided in this embodiment is combined with Figure 2 The Czochralski crystal growth control method is implemented using a Czochralski crystal growth device 100, which includes:

[0079] Step S10: starting the first magnetic field device 30 to apply a magnetic field to the melt 200 in the crucible 20;

[0080] Step S20 : ​​starting the second magnetic field device 50 to apply a magnetic field to the growth interface of the melt 200 .

[0081] It is easy to understand that the crystal growth regulation method of the pulling method can work in coordination by simultaneously setting up magnetic field devices around the crucible 20 and near the growth interface of the crystal 300. A stable macroscopic environment is provided around the crucible 20 to suppress the overall convection of the melt 200 and the macroscopic inhomogeneity of the solute, and the magnetic field at the growth interface optimizes the growth process of the crystal 300 at the microscopic level. It can jointly optimize the growth process of the crystal 300 at both the macroscopic and microscopic levels, stabilize the growth interface of the crystal 300, reduce various defects of the crystal 300, optimize the microstructure of the crystal 300, and thereby improve the quality and performance of the crystal 300 as a whole.

[0082] Specifically, please refer to Figure 3 , Figure 3 for Figure 2 The flowchart of the sub-steps of step S10 in Figure 3 , step S10 comprises:

[0083] Sub-step S11: during the melting stage of the polycrystalline material, starting the first magnetic field device 30 to apply a magnetic field of a first magnetic field strength to the polycrystalline material to obtain a melt 200;

[0084] Sub-step S12: in the shoulder release stage of the crystal, the first magnetic field device 30 is started, and a magnetic field with a gradually increasing magnetic field strength is applied to the melt 200 on the basis of the first magnetic field strength, until the magnetic field strength at the end of shoulder release reaches the second magnetic field strength;

[0085] Sub-step S13: in the crystal equal diameter stage, start the first magnetic field device 30 to apply a magnetic field of a second magnetic field strength to the melt 200;

[0086] Sub-step S14: At the end of the crystal formation, the first magnetic field device 30 is started to apply a magnetic field of a third magnetic field strength to the melt 200 .

[0087] The first magnetic field strength is smaller than the second magnetic field strength, and the second magnetic field strength is larger than the third magnetic field strength.

[0088] That is to say, in the melting stage of the polycrystalline material of the crystal, the first magnetic field strength acts on the polycrystalline material, and under the action of the magnetic field, the eddy currents generated inside will cause the polycrystalline material to melt; then in the shouldering stage of the crystal, on the basis of the first magnetic field strength, the magnetic field strength is continuously increased, and a slightly stronger magnetic field will produce a larger Lorentz force on the charged particles in the melt 200, thereby accelerating the convection of the melt 200 and making the temperature distribution more uniform, which is conducive to uniform shouldering of the crystal 300, until the end of the shouldering stage, the magnetic field will increase to the second magnetic field strength.

[0089] In the equal diameter stage of the crystal, the magnetic field strength is consistent with that in the shoulder release stage, ensuring a stable growth environment, enabling the solute to be transported to the growth interface of the crystal 300 at a stable rate, and enabling the crystal 300 to grow continuously and uniformly.

[0090] It should be noted that the third magnetic field strength can be a setting in which the magnetic field strength is gradually reduced on the basis of the second magnetic field strength. In this way, in the final stage of the crystal, the magnetic field strength is gradually reduced, which can slow down the convection of the melt 200, thereby avoiding tail defects in the crystal 300 caused by excessive convection or high temperature in the final stage, thereby ensuring the quality and performance of the prepared crystal 300.

[0091] Specifically, please refer to Figure 4 , Figure 4 for Figure 2 The flowchart of the sub-steps of step S20 in Figure 4 , step S20 comprises:

[0092] Sub-step S21: in the seed crystal seeding stage, start the second magnetic field device 50 to apply a magnetic field of a fourth magnetic field strength to the growth interface of the melt 200, and the direction of the magnetic field is a direction away from the growth interface;

[0093] Sub-step S22: During the crystal growth stage, the second magnetic field device 50 is started to apply a magnetic field of a fifth magnetic field strength to the growth interface of the melt 200, and the direction of the magnetic field is close to the growth interface.

[0094] The fourth magnetic field strength is less than the fifth magnetic field strength, and the growth stage includes the shoulder release stage, the equal diameter stage and the finishing stage. That is to say, from the seed crystal seeding stage to the crystal growth stage, the magnetic field strength is enhanced, and the magnetic field directions of the two stages are opposite.

[0095] Specifically, please refer to Figure 5 and Figure 6 , Figure 5 for Figure 4 Schematic diagram of magnetic field direction in neutron step S21, Figure 6 for Figure 4 The magnetic field direction diagram of the neutron step S22 is easy to understand. Figure 5 The direction of the magnetic field shown is the direction away from the crystal plane 310, which can also be understood as the upward direction; Figure 6 The direction of the magnetic field shown is a direction close to the crystal plane 310 , which can also be understood as a downward direction.

[0096] Combination Figure 4-Figure 6During the seed crystal induction stage, by setting a smaller magnetic field strength, it is possible to avoid the magnetic field from causing excessive interference to the seed crystal 400; at the same time, by setting this upward magnetic field, that is, the direction of the magnetic field is away from the crystallization plane 310, the solute convection can be accelerated, the solute can be quickly gathered at the growth interface, and the rapid growth of the crystal 300 can be promoted.

[0097] During the crystal growth stage, by setting a larger magnetic field strength, the lattice structure of the crystal 300 can grow more orderly under a suitable magnetic field; at the same time, by setting such a downward magnetic field, that is, changing the direction of the magnetic field so that it is reversely close to the crystallization surface 310, the convection of the melt 200 can be suppressed, which is conducive to the stable growth of the crystal 300. It is easy to understand that the quality and performance of the prepared crystal 300 can be further improved through the cooperation of sub-step S21 and sub-step S22.

[0098] In summary, an embodiment of the present invention provides a Czochralski crystal growth device 100 and a control method, wherein the Czochralski crystal growth device 100 includes a furnace body 10, a crucible 20, a first magnetic field device 30, a seed rod 40 and a second magnetic field device 50; the crucible 20 is arranged in the furnace body 10, and the first magnetic field device 30 is arranged around the outside of the crucible 20 and is located in the furnace body 10; the seed rod 40 is arranged in the furnace body 10 and is spaced apart from the crucible 20; the second magnetic field device 50 is arranged on the seed rod 40 and is located in the furnace body 10; wherein the first magnetic field device 30 is used to generate a magnetic field and act on the melt 200 in the crucible 20; the second magnetic field device 50 is used to generate a magnetic field and act on the growth interface of the melt 200.

[0099] The first magnetic field device 30 is used to macroscopically control the growth of the crystal 300. Specifically, different magnetic fields can be applied at different growth stages of the crystal 300. The magnetic field can generate Lorentz force on the charged particles in the melt 200, affecting the convection state of the melt 200, such as affecting the natural convection of the melt 200, thereby effectively inhibiting the convection of the melt 200, making the solute distribution uniform, and making the temperature distribution in the melt 200 more uniform, reducing the growth defects of the crystal 300 caused by the temperature gradient. At the same time, the second magnetic field device 50 is used to microscopically control the growth of the crystal 300. Specifically, different magnetic fields can be applied at different growth stages of the crystal 300, which can act on the growth interface of the crystal 300. The magnetic field will change the energy field near the seed crystal 400, affect the nucleation process of the crystal 300, and promote the more orderly growth of the crystal 300; and accurately control the distribution of the solute on a microscopic scale to meet the requirements of the crystal 300 for specific performance, and can achieve accurate control of the doping concentration, thereby optimizing the microstructure of the crystal 300 and improving the stability of the crystal 300. That is to say, through the coordinated cooperation of the first magnetic field device 30 and the second magnetic field device 50, the growth process of the crystal 300 can be jointly optimized at both the macro and micro levels, various defects of the crystal 300 can be reduced, thereby improving the quality and performance of the crystal 300 as a whole.

[0100] The CZC crystal growth control method is implemented by using a CZC crystal growth device 100, which includes: starting the first magnetic field device 30 and applying a magnetic field to the melt 200 in the crucible 20; starting the second magnetic field device 50 and applying a magnetic field to the growth interface of the melt 200. The CZC crystal growth control method can work in coordination by simultaneously setting magnetic field devices around the crucible 20 and near the growth interface of the crystal 300. A stable macroscopic environment is provided around the crucible 20 to suppress the overall convection of the melt 200 and the macroscopic inhomogeneity of the solute, and the magnetic field at the growth interface optimizes the growth process of the crystal 300 at the microscopic level; the growth process of the crystal 300 can be jointly optimized at both the macroscopic and microscopic levels, the growth interface of the crystal 300 is stabilized, various defects of the crystal 300 are reduced, and the microscopic structure of the crystal 300 is optimized, thereby improving the quality and performance of the crystal 300 as a whole.

[0101] The above description is only a specific embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Czochralski crystal growth device, characterized in that: include: Furnace body (10); a crucible (20), wherein the crucible (20) is arranged in the furnace body (10); A first magnetic field device (30), the first magnetic field device (30) being arranged around the outside of the crucible (20) and located inside the furnace body (10); A seed crystal rod (40), the seed crystal rod (40) being arranged in the furnace body (10) and spaced apart from the crucible (20); as well as A second magnetic field device (50), the second magnetic field device (50) being arranged on the seed crystal rod (40) and located inside the furnace body (10); The first magnetic field device (30) is used to generate a magnetic field and act on the melt (200) in the crucible (20); and the second magnetic field device (50) is used to generate a magnetic field and act on the growth interface of the melt (200).

2. The Czochralski crystal growth device according to claim 1, characterized in that: The second magnetic field device (50) comprises a spiral tube coil (51) and a fixed sleeve (52), wherein the fixed sleeve (52) is sleeved on one end of the seed crystal rod (40) close to the crucible (20), and the spiral tube coil (51) is sleeved on the fixed sleeve (52).

3. The Czochralski crystal growth device according to claim 2, characterized in that: The outer side wall of the fixed sleeve (52) is provided with a first spiral groove (521), and the spiral tube coil (51) is arranged in the first spiral groove (521).

4. The Czochralski crystal growth device according to claim 2, characterized in that: The second magnetic field device (50) further comprises a power line (53) and a signal line (54), wherein the power line (53) and the signal line (54) are both sleeved on the seed crystal rod (40), and the power line (53) and the signal line (54) are both connected to the solenoid coil (51).

5. The Czochralski crystal growth device according to claim 4, characterized in that: The outer wall of the seed crystal rod (40) is provided with a second spiral groove, and the power line (53) is arranged in the second spiral groove; and / or, The outer wall of the seed crystal rod (40) is provided with a third spiral groove, and the signal line (54) is arranged in the third spiral groove.

6. The Czochralski crystal growth device according to claim 1, characterized in that: The distance between the bottom of the second magnetic field device (50) and the top of the crucible (20) is 1 cm to 10 cm.

7. The Czochralski crystal growth device according to claim 1, characterized in that: The magnetic field strength produced by the second magnetic field device (50) is 100 Gs to 1000 Gs.

8. A method for controlling crystal growth by a Czochralski method, characterized in that: The CZC crystal growth device (100) according to any one of claims 1 to 7 is used to implement the method for controlling crystal growth by the CZC method, comprising: Starting the first magnetic field device (30) to apply a magnetic field to the melt (200) in the crucible (20); The second magnetic field device (50) is started to apply a magnetic field to the growth interface of the melt (200).

9. The method for controlling crystal growth by the Czochralski method according to claim 8, characterized in that: The step of starting the first magnetic field device (30) to apply a magnetic field to the melt (200) in the crucible (20) comprises: In the melting stage of the polycrystalline material, the first magnetic field device (30) is started to apply a magnetic field of a first magnetic field strength to the polycrystalline material to obtain the melt (200); In the shoulder release stage of the crystal, the first magnetic field device (30) is started, and a magnetic field with a gradually increasing magnetic field strength is applied to the melt (200) on the basis of the first magnetic field strength, until the magnetic field strength at the end of the shoulder release is a second magnetic field strength; At the crystal equal diameter stage, starting the first magnetic field device (30) to apply the magnetic field of the second magnetic field strength to the melt (200); At the end of the crystal formation, the first magnetic field device (30) is started to apply a magnetic field of a third magnetic field strength to the melt (200); The first magnetic field strength is smaller than the second magnetic field strength, and the second magnetic field strength is larger than the third magnetic field strength.

10. The method for controlling crystal growth by the Czochralski method according to claim 8, characterized in that: The step of starting the second magnetic field device (50) to apply a magnetic field to the growth interface of the melt (200) comprises: In the seed crystal seeding stage, the second magnetic field device (50) is started to apply a magnetic field of a fourth magnetic field strength to the growth interface of the melt (200), and the direction of the magnetic field is a direction away from the growth interface; During the crystal growth stage, the second magnetic field device (50) is started to apply a magnetic field of a fifth magnetic field strength to the growth interface of the melt (200), wherein the direction of the magnetic field is close to the growth interface; The fourth magnetic field strength is smaller than the fifth magnetic field strength, and the growth stage includes a shoulder release stage, an equal diameter stage and a finishing stage.

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