CN218291175U - Magnetic control crystal pulling device - Google Patents

Abstract

The embodiment of the application provides a magnetron crystal pulling device, which comprises a single crystal furnace, a crucible and a magnetron assembly; the crucible is arranged in the single crystal furnace and used for containing silicon liquid, and the magnetic control assembly is arranged above the silicon liquid. The magnetic control assembly comprises an annular magnet, wherein a crystal pulling channel for the monocrystalline silicon rod to penetrate through is arranged in the annular magnet, and the annular magnet is arranged close to the silicon liquid and is used for forming a hook-shaped magnetic field in the silicon liquid. The magnetic field intensity of the hook-shaped magnetic field on the liquid surface of the silicon liquid is more than or equal to 0.1 millitex. The hook-shaped magnetic field in the silicon liquid can effectively inhibit longitudinal thermal convection, transverse thermal convection and other thermal convection of the silicon liquid, and inhibit the thermal convection of the silicon liquid in multiple directions. Therefore, the scouring of the silicon liquid to the crucible wall can be reduced, the impurity content in the silicon liquid is reduced, and the crystal pulling quality is improved. Moreover, the magnetron crystal pulling device is simple in structure, can be implemented by only carrying out a small amount of improvement on the basis of the existing crystal pulling device, and is wide in application range and low in cost.

Description

Magnetic control crystal pulling device

Technical Field

The application belongs to the technical field of photovoltaics, and particularly relates to a magnetic control crystal pulling device.

Background

In the Field of photovoltaic technology, in order to improve the quality of crystals in the production of monocrystalline silicon, crystals are generally pulled by means of a Magnetic Field Applied Czochralski Method (MCZ) using a magnetron pulling apparatus.

In the prior art, a magnetic field generating device is arranged in a magnetron crystal pulling device, and a magnetic field generated by the magnetic field generating device penetrates silicon liquid in a crucible, so that the silicon liquid and the magnetic field interact to generate Lorentz force, thereby inhibiting the heat convection of the silicon liquid and the scouring of the silicon liquid on the crucible wall, reducing the influence caused by uneven crystal pulling and reducing impurities in the silicon liquid. Therefore, the magnetron crystal pulling apparatus has an important influence on the production of single crystal silicon.

However, in the process of researching the prior art, the inventor finds that the magnetic field generating device can only inhibit the thermal convection of the silicon liquid in a single direction, namely the longitudinal direction or the transverse direction, and the inhibition effect is limited. And the existing magnetic field generating equipment is mostly arranged outside the furnace body, the structure is complex and large, the original crystal pulling device needs to be greatly modified, the engineering quantity is large, the period is long, and the production cost is greatly increased.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention has been developed to provide a magnetron crystal pulling apparatus that overcomes, or at least partially solves, the above-mentioned problems.

In order to solve the technical problem, the present application is implemented as follows:

the embodiment of the application provides a magnetron crystal pulling device, which comprises a single crystal furnace, a crucible and a magnetron assembly;

the crucible is arranged in the single crystal furnace and used for containing silicon liquid, and the magnetic control assembly is arranged above the silicon liquid;

the magnetic control assembly comprises an annular magnet, a crystal pulling channel for a monocrystalline silicon rod to penetrate through is arranged in the annular magnet, and the annular magnet is arranged close to the silicon liquid and is used for forming a hook-shaped magnetic field in the silicon liquid;

the magnetic field intensity of the hook-shaped magnetic field on the liquid surface of the silicon liquid is more than or equal to 0.1 millitex.

Optionally, the ring magnet is of an integrally formed structure.

Optionally, the annular magnet is of a split structure, and the annular magnet includes a plurality of magnetic pieces, and the plurality of magnetic pieces are sequentially distributed along the circumferential direction to form the crystal pulling channel.

Optionally, in the plurality of magnetic members, two adjacent magnetic members abut against each other.

Optionally, in the plurality of magnetic members, two adjacent magnetic members are disposed at an interval.

Optionally, in the plurality of magnetic members, the magnetic poles of each of the magnetic members are distributed identically.

Optionally, the ring magnet comprises an inner side wall and an outer side wall which are oppositely arranged, and a top surface and a bottom surface which are respectively connected with the inner side wall and the outer side wall;

the poles of the ring magnet comprise a first pole and a second pole, the first pole being opposite the second pole;

the first magnetic pole is arranged on the inner side wall, and the second magnetic pole is arranged on the outer side wall, or the first magnetic pole is arranged on the top surface, and the second magnetic pole is arranged on the bottom surface.

Optionally, a heat exchanger is arranged in the single crystal furnace, the heat exchanger is arranged above the crucible, and the magnetron assembly is connected to the heat exchanger.

Optionally, the spacing between the inner wall of the ring magnet and the outer wall of the single crystal silicon rod comprises any one of 2-10 centimeters.

Optionally, the magnetron assembly further comprises a cooling layer and a thermal insulation layer;

the cooling layer covers the annular magnet, the heat insulation layer covers the cooling layer, and a cooling medium is filled in the cooling layer.

In the embodiment of the application, the magnetron crystal pulling device comprises a single crystal furnace, a crucible and a magnetron assembly; the crucible is arranged in the single crystal furnace and used for containing silicon liquid, and the magnetic control assembly is arranged above the silicon liquid; the magnetic control assembly comprises an annular magnet, a crystal pulling channel for a silicon single crystal rod to penetrate through is arranged in the annular magnet, the annular magnet is arranged close to the silicon liquid and is used for forming a hook-shaped magnetic field in the silicon liquid, and the magnetic field intensity of the hook-shaped magnetic field on the liquid level of the silicon liquid is greater than or equal to 0.1 millitex. Through in this application the magnetic control crystal pulling device is provided with the magnetic control subassembly, the magnetic control subassembly connect in the heat exchanger, be provided with in the magnetic control subassembly the ring magnet, at least part of ring magnet is located in the crucible, so that the ring magnet can be close to in the crucible silicon liquid sets up, and form in the silicon liquid collude type magnetic field. In a specific application, under the condition that the magnetic field intensity of the hook-shaped magnetic field on the liquid surface of the silicon liquid is greater than or equal to 0.1 Hatt, the hook-shaped magnetic field in the silicon liquid can effectively inhibit longitudinal thermal convection, transverse thermal convection and other thermal convection of the silicon liquid, and inhibit the thermal convection of the silicon liquid in multiple directions. Therefore, the scouring of the silicon liquid to the crucible wall can be reduced, the impurity content in the silicon liquid is reduced, and the crystal pulling quality is improved. Moreover, the magnetron crystal pulling device is simple in structure, can be implemented by only carrying out a small amount of improvement on the basis of the conventional crystal pulling device, and is wide in application range and low in cost.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural view of a magnetron crystal pulling apparatus according to an embodiment of the present application;

FIG. 2 is a schematic view of a portion of the magnetic induction lines of a magnetron crystal pulling apparatus according to an embodiment of the present application;

FIG. 3 is a schematic view of a portion of a magnetron crystal pulling apparatus according to an embodiment of the present application;

fig. 4 is one of schematic structural diagrams of a ring magnet according to an embodiment of the present application;

fig. 5 is a second schematic structural diagram of a ring magnet according to an embodiment of the present application;

fig. 6 is a third schematic structural diagram of a ring magnet according to an embodiment of the present application;

FIG. 7 is a fourth schematic view of a ring magnet according to an embodiment of the present application;

fig. 8 is a fifth schematic structural view of a ring magnet according to an embodiment of the present application;

fig. 9 is a sixth schematic view illustrating a structure of a ring magnet according to an embodiment of the present application;

FIG. 10 is a schematic structural diagram of a magnetron assembly according to an embodiment of the present application.

Reference numerals: 10-a single crystal furnace; 20-a crucible; 30-a magnetic control assembly; 11-a heat exchanger; 12-a heater; 13-a support rod; 31-a ring magnet; 311-magnetic induction lines; 21-silicon liquid; 22-single crystal silicon rod; 23-a crystal pulling channel; 32-a magnetic member; 33-inner side wall; 34-an outer side wall; 35-top surface; 36-a bottom surface; 37-a cooling layer; 38-a thermally insulating layer; 301-an annular body; 302-water inlet pipe; 303-water outlet pipe.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The features of the terms first and second in the description and in the claims of the present application may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specified. In addition, "and/or" in the specification and claims means at least one of connected objects, a character "/" generally means that a preceding and succeeding related objects are in an "or" relationship.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship indicated based on the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Production of single crystal silicon rod 22 is typically obtained by the Czochralski method in single crystal furnace 10. In order to improve the quality of the single crystal silicon rod 22 during the production of single crystal silicon and avoid the undesirable effects of high impurity content, uneven distribution, and the like, crystal pulling is generally performed by a magnetron crystal pulling method. Specifically, in the czochralski method using the magnetron pulling apparatus, a magnetic field is applied to a portion of the molten silicon melt 21, and the magnetic induction lines 311 generated by the magnetic field are cut by thermal convection of the silicon melt 21, thereby generating a lorentz force and suppressing the thermal convection of the silicon melt 21. The single crystal silicon rod 22 with lower impurity content and more uniform distribution is prepared.

Referring to fig. 1 to 10, there are shown schematic structural diagrams of a magnetron crystal pulling apparatus according to an embodiment of the present application, which may specifically include: a single crystal furnace 10, a crucible 20, and a magnetron assembly 30; the crucible 20 is arranged in the single crystal furnace 10 and used for containing the silicon liquid 21, and the magnetron assembly 30 is arranged above the silicon liquid 21; the magnetic control assembly 30 comprises a ring-shaped magnet 31, a crystal pulling channel 23 for the monocrystalline silicon rod 22 to penetrate through is arranged in the ring-shaped magnet 31, and the ring-shaped magnet 31 is arranged close to the silicon liquid 21 and is used for forming a cusp-shaped magnetic field in the silicon liquid 21. The magnetic field intensity of the hook-shaped magnetic field on the liquid surface of the silicon liquid 21 is more than or equal to 0.1 millitex.

In the embodiment of the application, the magnetron crystal pulling device is provided with a magnetron assembly 30, the magnetron assembly 30 is connected to the heat exchanger 11, a ring-shaped magnet 31 is arranged in the magnetron assembly 30, and at least part of the ring-shaped magnet 31 is positioned in the crucible 20, so that the ring-shaped magnet 31 can be arranged close to the silicon liquid 21 in the crucible 20 and form a cusp-type magnetic field 311 in the silicon liquid 21. Specifically, the ring magnet 31 has the maximum magnetic field intensity in the magnetic field generated in the silicon liquid 21 at the liquid level position of the silicon liquid 21. The maximum magnetic field intensity of the hook-shaped magnetic field on the liquid surface of the silicon liquid 21 is greater than or equal to 0.1 millitex (symbol mT), so that the annular magnet 31 has a good heat convection suppression effect on all the silicon liquids 21, and the phenomenon that the magnetic field formed by the silicon liquid 21 far away from the annular magnet 31 is weak, so that the obvious suppression effect is hardly played, and the economy is lost is avoided. Thus, the hook-shaped magnetic field in the silicon liquid 21 can effectively inhibit longitudinal thermal convection, transverse thermal convection and other directions of the silicon liquid 21, and inhibit the thermal convection of the silicon liquid 21 in multiple directions. Thereby reducing the scouring of the silicon liquid 21 to the crucible 20 wall, reducing the impurity content in the silicon liquid 21 and improving the crystal pulling quality. Moreover, the magnetron crystal pulling device is simple in structure, can be implemented by only slightly improving the conventional crystal pulling device, and is wide in application range and low in cost.

Specifically, in the present embodiment, the magnetic field strength of the ring magnet 31 refers to its "remanent magnetization" (reference), symbol Br; the magnetic field intensity at the liquid surface of the silicon liquid 21 is a vector, which is a "magnetic flux density" at that position, and the magnitude is the magnitude of the absolute value thereof and is indicated by the symbol B, and both are expressed in tesla (symbol T) in the international common unit.

In practice, the crystal pulling apparatus may generally consist of a single crystal furnace 10, a heater 12, a heat exchanger 11, a crucible 20, and a support rod 12. The heater 12 is disposed adjacent to the crucible 20 to heat the silicon material in the crucible 20 into the silicon liquid 21 and to maintain the silicon liquid 21 at a temperature suitable for growing the ingot. The support rod 13 is connected to the bottom of the crucible 20 to support the crucible 20. The crucible 20 may specifically include at least one of a quartz crucible and a graphite crucible, and the specific material of the crucible 20 in the embodiment of the present application may not be limited.

Referring to fig. 2, a schematic diagram of magnetic induction lines of a cusp-type magnetic field in the embodiment of the present application is shown. As shown in fig. 2, the magnetic induction lines 311 of the hook-shaped magnetic field in the silicon solution 21 are arc-shaped magnetic induction lines 311. Thus, the partial magnetic induction lines 311 cut the longitudinal thermal convection in the silicon fluid 21, generate lorentz force, and suppress the longitudinal thermal convection in the silicon fluid 21. Meanwhile, the other part of the magnetic induction lines 311 can cut the transverse thermal convection in the silicon liquid 21 to generate a lorentz force, so that the transverse thermal convection in the silicon liquid 21 is inhibited. Furthermore, the lines of magnetic induction 311 can also generate lorentz forces by thermal convection in directions other than the longitudinal and transverse directions. For example, the other direction may be a direction having an inclination angle of 45 °, 60 ° or the like with respect to the lateral direction. Therefore, the effect of inhibiting heat convection in multiple directions in the silicon liquid 21 is achieved, the utilization rate of the magnetic field is almost constant, the high utilization rate is achieved, and the effect of inhibiting heat convection in the silicon liquid 21 by the magnetic control assembly 30 is improved.

In some alternative embodiments of the present application, the heat exchanger 11 includes a top end and a bottom end disposed away from each other, and the magnetron assembly 30 may be attached to the bottom end of the heat exchanger 11. Thus, the magnetron assembly 30 can be positioned at the position closest to the liquid surface without adding other mounting structures, and the magnetron assembly 30 has a better inhibition effect on the heat convection of the silicon liquid 21.

Specifically, in the embodiment of the present application, the magnetron assembly 30 may be installed inside the heat exchanger 11, or may be installed outside the heat exchanger 11, and a specific installation manner of the magnetron assembly 30 in the embodiment of the present application may not be limited.

Illustratively, the detailed structure of the magnetron assembly 30 is shown in fig. 3, and the magnetron assembly 30 may include a heat exchanger 11 and a ring magnet 31; the heat exchanger 11 comprises an annular body 301, an inlet pipe 302, and an outlet pipe 303. An annular cavity is arranged in the annular body 301 and is used for accommodating a cooling medium. The water inlet pipe 302 is communicated with the annular cavity, and the water inlet pipe 302 is used for leading the cooling medium into the annular cavity. The water outlet pipe 303 is communicated with the annular cavity, and the water outlet pipe 303 is used for guiding out the cooling medium in the annular cavity. A ring magnet 31 is attached to a side of the ring-shaped body 301 adjacent to the crucible 20.

In the process of pulling the single crystal silicon rod 22, the heat released during crystallization of the single crystal silicon rod 22 can be quickly taken away by the circulation of the cooling medium in the annular cavity, so that the pulling speed of the single crystal silicon rod 22 is increased. Specifically, the annular body 301 may be made of a metal material having a certain strength. A channel is provided in the ring-shaped body 301, which channel communicates with the crystal pulling channel 23 and is intended for the passage of the monocrystalline silicon rod 22 along the crystal pulling channel 23. Because the circulating cooling medium can be continuously introduced into the annular cavity of the annular body 301, when the single crystal silicon rod 22 passes through the channel of the annular body 301 and the crystal pulling channel 23, heat exchange can be performed between the circulating cooling medium and the cooling medium in the annular cavity, so that latent heat of crystallization of the single crystal silicon rod 22 can be rapidly taken away, and the pulling speed of the single crystal silicon rod 22 can be increased.

Specifically, the water inlet pipe 302 may be connected to the bottom of the annular cavity, and the water outlet pipe 303 may be connected to the top of the annular cavity. Thus, the cooling medium can enter from the bottom of the annular cavity through the water inlet pipe 302, and flow out from the water outlet pipe 303 at the top after flowing through the annular cavity, so that heat conduction is realized.

In the embodiment of the present application, the ring magnet 31 may be disposed on a side of the ring-shaped cavity close to the crucible 20, and at least a portion of the ring magnet 31 may extend into the crucible 20, so that the ring magnet 31 may be disposed close to the silicon fluid 21 in the crucible 20 and form a cusp-type magnetic field in the silicon fluid 21.

For example, in the embodiment of the present application, the ring magnet 31 may be a permanent magnet, such as an iron-boron magnet, an electromagnet, a combination of a permanent magnet and an electromagnet, and the like, and the specific form of the ring magnet 31 may not be limited in the embodiment of the present application.

Alternatively, in the embodiment of the present application, as shown in fig. 4, the ring magnet 31 is an integrally formed structure, so that the ring magnet 31 can be processed, material loss and manufacturing processes are reduced, and the ring magnet 31 has a strong magnetic field.

In some alternative embodiments of the present application, as shown in fig. 5 to 7, the ring magnet 31 may be a split structure. In particular, the ring magnet 31 may comprise a plurality of magnetic elements 32, the plurality of magnetic elements 32 being distributed circumferentially one after the other to form the pull channel 23. Thus, the arrangement position of the ring magnet 31 can be flexibly set, the single crystal furnace is suitable for various single crystal furnaces 10 with different structures, and partial structure distribution in the single crystal furnace 10 can be avoided.

Specifically, the magnetic member 32 may be a ferromagnetic member or an electromagnetic coil module, and the specific type of the magnetic member 32 may not be limited in the embodiment of the present application. As shown in fig. 4 to 7, different distributions of the magnetic members 32 as ferromagnetic members are shown. Where magnetic member 32 is a ferromagnetic member, the ferromagnetic member may include, but is not limited to, any one of samarium cobalt magnets, neodymium iron boron magnets, and iron oxide magnets. Because the ferromagnetic component has a simple structure and a low cost, when the magnetic component 32 is a ferromagnetic component, the structure of the magnetic component 32 can be relatively simple and the cost is low. In the case where the magnetic member 32 is a solenoid module that can generate a magnetic field when energized, each solenoid module resembles a magnetic block.

Alternatively, in the embodiment of the present application, as shown in fig. 5, of the plurality of magnetic members 32, two adjacent magnetic members 32 abut against each other. Therefore, the plurality of magnetic pieces 32 are convenient to enclose to form a complete ring shape, and the ring magnet 31 has good stability and can generate a strong magnetic field.

In the embodiment of the present application, optionally, in the plurality of magnetic members 32, as shown in fig. 6 to 7, two adjacent magnetic members 32 are disposed at intervals. Thus, the single crystal furnace 10 can be applied to various single crystal furnaces 10 with different structures, and the partial structure distribution which can cause interference in the single crystal furnace 10 can be avoided during installation. In addition, the material of the annular magnet 31 can be saved, and the production cost can be reduced.

For example, in the embodiment of the present application, the cross section of the magnetic member 32 includes at least one of an arc-shaped surface and a rectangular surface, which facilitates adapting to different application scenarios and improves compatibility of the magnetron assembly 30. As shown in fig. 6, the cross section of the magnetic member 32 includes an arc-shaped surface, and the magnetic members 32 of a plurality of arc-shaped surfaces surround to form a circular ring magnet, so that the magnetic members 32 of the arc-shaped surfaces can better form the circular ring magnet 31 in a smaller number. As shown in fig. 7, the cross section of the magnetic member 32 includes rectangular surfaces, and the plurality of magnetic members 32 with rectangular surfaces surround to form a ring magnet, so that the distribution mode is more flexible, and the single crystal furnace 10 is suitable for various structures. In addition, the ring magnet 31 may further include a combination of an arc-shaped magnetic member 32 and a rectangular-shaped magnetic member 32, which is not limited in this embodiment.

Alternatively, in the present embodiment, the magnetic poles of each of the plurality of magnetic members 32 are distributed identically. Thus, the annular magnet 31 formed by the plurality of magnetic members 32 distributed around the axial direction has a larger magnetic field intensity, so that the magnetic assembly has a better inhibiting effect on the heat convection effect of the silicon liquid 21.

Specifically, in the embodiment of the present application, the magnetic poles of each magnetic member 32 are distributed uniformly, which means that if one magnetic member 32 is N-pole at the end close to the pull channel 23 and S-pole at the end far from the pull channel 23, the other magnetic member 32 is N-pole at the end close to the pull channel 23 and S-pole at the end far from the pull channel 23. If one of the magnetic members 32 is S-pole at the end close to the pull channel 23 and N-pole at the end far from the pull channel 23, the magnetic pole at the end close to the pull channel 23 of the other magnetic member 32 is also S-pole and the magnetic pole at the end far from the pull channel 23 is also N-pole. And analogize, the magnetic poles at the end of each magnetic member 32 close to the pulling channel 23 are all N poles, and the magnetic poles at the end far away from the pulling channel 23 are all S poles, or the magnetic poles at the end of each magnetic member 32 close to the pulling channel 23 are all S poles, and the magnetic poles at the end far away from the pulling channel 23 are all N poles. The specific magnetic pole distribution of each magnetic member 32 in the embodiment of the present application may not be limited.

It should be noted that the magnetic pole distribution of each magnetic member 32 may be different. That is, one end of the magnetic member 32 close to the pull channel 23 is N-pole, and the other end of the magnetic member away from the pull channel 23 is S-pole; the magnetic pole of the other magnetic member 32 at the end close to the pull channel 23 can be an S pole, and the magnetic pole at the end far away from the pull channel 23 can be an N pole.

Alternatively, in the present embodiment, the ring magnet 31 includes an inner sidewall 33 and an outer sidewall 34 disposed opposite to each other, and a top surface 35 and a bottom surface 36 connected to the inner sidewall 33 and the outer sidewall 34, respectively. The magnetic poles of the ring magnet 31 include a first magnetic pole and a second magnetic pole, and the first magnetic pole is opposite to the second magnetic pole. As shown in fig. 9, the first magnetic pole is disposed on the inner sidewall 33, and the second magnetic pole is disposed on the outer sidewall 34. Alternatively, as shown in fig. 8, the first magnetic pole is disposed on the top surface 35 and the second magnetic pole is disposed on the bottom surface 36. Thus, in the embodiment of the present application, the ring magnets 31 with different magnetic pole distributions may be adopted, and applied to different practical use scenarios, so as to improve the compatibility of the magnetron assembly 30.

For example, in the embodiment of the present application, when the first magnetic pole is an N pole, the second magnetic pole is an S pole, and the inner sidewall 33 may be an N pole, and the outer sidewall 34 may be an S pole, forming a radially distributed magnetic field. Alternatively, the top surface 35 may be provided as an N-pole and the bottom surface 36 as an S-pole, forming a longitudinally distributed magnetic field. When the first magnetic pole is an S-pole, the second magnetic pole is an N-pole, and the radially distributed magnetic field may be formed by providing the inner sidewall 33 as an S-pole and the outer sidewall 34 as an N-pole. Alternatively, the top surface 35 may be S-pole and the bottom surface 36 may be N-pole, forming a longitudinally distributed magnetic field.

In the embodiment of the present application, specifically, the first magnetic pole may be an N pole, and the second magnetic pole may be an S pole, or the first magnetic pole may be an S pole, and the second magnetic pole may be an N pole. The embodiment of the present application may not be limited thereto.

Furthermore, the ring magnet 31 may be inclined at an angle, such as 45 °, 60 °, etc., to form magnetic field distributions in various directions. The inclination angle at which the ring magnet 31 is inclined in the embodiment of the present application may not be limited.

Referring to table 1 below, in the simulation experiment, the control experiment was performed with the magnetic field distribution set to the radial distribution magnetic field, the longitudinal distribution magnetic field, the magnetic field distribution in which the inclination angle of the ring magnet 31 is 45 °, and without the magnetron assemblies 30, respectively. As shown in table 1, in the case where the magnetic field strengths were all set to 1.2T (Tesla, tex), the highest flow rate of the silicon liquid 21 in the radial distribution magnetic field was 0.013m/s, the highest flow rate of the silicon liquid 21 in the longitudinal distribution magnetic field was 0.027m/s, the highest flow rate of the silicon liquid 21 in the magnetic field distribution in which the inclination angle of the ring magnet 31 was 45 ° was 0.034m/s, and the highest flow rate of the silicon liquid 21 in the non-magnetic field distribution was 0.055m/s.

TABLE 1

Thus, the three magnetic field distributions can well inhibit the thermal convection of the silicon liquid 21. Wherein the radially distributed magnetic field is superior to the thermal convection of the silicon liquid 21. That is, the radial magnetic field effect is good when the inner wall 33 of the ring magnet 31 is an N pole and the outer wall 34 is an S pole, or when the inner wall 33 of the ring magnet 31 is an S pole and the outer wall 34 is an N pole.

In the embodiment of the present application, the distance between the inner wall of the ring magnet 31 and the outer wall of the single crystal silicon rod 22 may optionally include any value of 2-10 cm. That is, if the inner diameter of the ring magnet 31 is D1 and the outer diameter of the single crystal silicon rod 22 is D2, D2-D1 of 4cm or more is less than or equal to 20cm or less, so that the ring magnet 31 can have a good effect of suppressing the heat convection of the silicon liquid 21 without affecting the crystal pulling. It is avoided that the small distance between the inner wall of the ring magnet 31 and the outer wall of the single crystal silicon rod 22 impedes the flow of protective gas along the crystal pulling channel 23 and the observation of the solid-liquid growth interface during the operation of the crystal growth. The large distance between the inner wall of the annular magnet 31 and the outer wall of the single crystal silicon rod 22 is avoided, and the inhibition effect of the magnetic control assembly 30 on the heat convection of the silicon liquid 21 is weakened.

In the embodiment of the present application, if the outer diameter of the ring magnet 31 is D3, the inner diameter of the crucible 20 is D4, and D3< D4 is set, the ring magnet 31 can be located in the crucible 20 to be close to the upper side of the liquid level of the silicon liquid 21, so that the magnetic field generated by the magnetron assembly 30 is strong.

Specifically, in the present embodiment, in the case where the ring magnet 31 is installed outside the bottom end of the heat exchanger 11, the distance between the ring magnet 31 and the liquid surface of the silicon liquid 21 includes any one of 2 to 10 centimeters (denoted by cm). Thus, the ring magnet 31 has a good pulling effect on the single crystal silicon rod 22, and does not affect the growth of the single crystal silicon rod 22. The small distance between the annular magnet 31 and the liquid surface of the silicon liquid 21 is avoided, so that the protective gas is prevented from flowing along the crystal pulling channel 23, and the solid-liquid growth interface is prevented from being observed when the crystal growth is operated. The larger distance between the annular magnet 31 and the liquid level of the silicon liquid 21 is avoided, and the inhibition effect of the magnetron assembly 30 on the heat convection of the silicon liquid 21 is weakened.

Optionally, in the embodiment of the present application, the magnetron assembly 30 further includes a cooling layer 37 and a heat insulating layer 38, the cooling layer 37 is coated on the ring magnet 31, the heat insulating layer 38 is coated on the cooling layer 37, and a cooling medium is introduced into the cooling layer 37, so as to avoid magnetic failure of the ring magnet 31 and prolong the service life of the magnetron crystal pulling apparatus.

In practical application, a higher temperature is required to be applied in the single crystal furnace 10 during the crystal pulling process, the silicon liquid 21 is in a molten state and has a higher temperature, and a high temperature exceeding 1400 ℃ can be generated in the single crystal furnace 10, so that the magnetron assembly 30 is easily damaged. Such as causing the energized coil to burn out, demagnetizing the permanent magnet, etc. Therefore, the influence of the high temperature generated by the silicon liquid 21 on the ring magnet 31 is blocked by the heat insulating layer 38, and the temperature of the ring magnet 31 is reduced by the cooling medium in the cooling layer 37, so as to avoid the magnetic failure of the ring magnet 31.

For example, the material of the thermal insulation layer 38 may include at least one of metal, ceramic, and refractory material with low thermal conductivity, and the thermal conductivity thereof may be lower than 50 w/(m × k), and the thermal insulation layer can withstand a temperature higher than 1000 ℃, and has a better high temperature resistance. The heat insulating layer 38 may be made of any one of the above materials, or may be made of any combination of the above materials, which is not limited in the embodiment of the present application.

Specifically, the cooling layer 37 may be filled with a flowing cooling medium, or may be filled with a non-flowing cooling medium for periodic replacement, which is not limited in the embodiment of the present application. For example, the material of the cooling medium may include water, gas or other liquid, etc. to cool the ring magnet 31, so that the temperature of the ring magnet 31 is less than or equal to 300 ℃, and the generated magnetic field is not affected.

In summary, the magnetron crystal pulling apparatus according to the embodiments of the present application may include at least the following advantages:

in an embodiment of the application, the magnetron crystal pulling apparatus comprises a single crystal furnace, a crucible, and a magnetron assembly; the crucible is arranged in the single crystal furnace and used for containing silicon liquid, and the magnetic control assembly is arranged above the silicon liquid; the magnetic control assembly comprises an annular magnet, a crystal pulling channel for a silicon single crystal rod to penetrate through is arranged in the annular magnet, the annular magnet is arranged close to the silicon liquid and is used for forming a hook-shaped magnetic field in the silicon liquid, and the magnetic field intensity of the hook-shaped magnetic field on the liquid level of the silicon liquid is greater than or equal to 0.1 millitex. Through in this application the magnetic control crystal pulling device is provided with the magnetic control subassembly, the magnetic control subassembly connect in the heat exchanger, be provided with in the magnetic control subassembly the ring magnet, at least part of ring magnet is located in the crucible, so that the ring magnet can be close to in the crucible silicon liquid sets up, and form in the silicon liquid collude type magnetic field. In a specific application, under the condition that the magnetic field intensity of the hook-shaped magnetic field on the liquid surface of the silicon liquid is greater than or equal to 0.1 Hatt, the hook-shaped magnetic field in the silicon liquid can effectively inhibit longitudinal thermal convection, transverse thermal convection and other thermal convection of the silicon liquid, and inhibit the thermal convection of the silicon liquid in multiple directions. Therefore, the scouring of the silicon liquid to the crucible wall can be reduced, the impurity content in the silicon liquid is reduced, and the crystal pulling quality is improved. Moreover, the magnetron crystal pulling device is simple in structure, can be implemented by only carrying out a small amount of improvement on the basis of the conventional crystal pulling device, and is wide in application range and low in cost.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims (10)

1. A magnetron crystal pulling device is characterized by comprising a single crystal furnace, a crucible and a magnetron component;

the crucible is arranged in the single crystal furnace and used for containing silicon liquid, and the magnetic control assembly is arranged above the silicon liquid;

the magnetic control assembly comprises an annular magnet, a crystal pulling channel for a monocrystalline silicon rod to penetrate through is arranged in the annular magnet, and the annular magnet is arranged close to the silicon liquid and is used for forming a hook-shaped magnetic field in the silicon liquid;

the magnetic field intensity of the hook-shaped magnetic field on the liquid surface of the silicon liquid is more than or equal to 0.1 millitex.

2. A magnetron crystal pulling apparatus as claimed in claim 1 wherein the ring magnet is of unitary construction.

3. A magnetron crystal pulling apparatus as claimed in claim 1 wherein the annular magnet is of split construction and the annular magnet includes a plurality of magnetic members which are distributed circumferentially in sequence to form the crystal pulling channel.

4. A magnetron crystal pulling apparatus as claimed in claim 3 wherein adjacent ones of the plurality of magnetic members abut.

5. A magnetron crystal pulling apparatus as claimed in claim 3 wherein adjacent ones of the plurality of magnetic members are spaced apart.

6. A magnetron crystal pulling apparatus as claimed in claim 4, wherein the magnetic poles of each of the plurality of magnetic members are equally distributed.

7. A magnetron crystal pulling apparatus as claimed in claim 1, wherein the ring magnet includes oppositely disposed inner and outer side walls and top and bottom surfaces connected to the inner and outer side walls, respectively;

the poles of the ring magnet comprise a first pole and a second pole, the first pole being opposite the second pole;

the first magnetic pole is arranged on the inner side wall, and the second magnetic pole is arranged on the outer side wall, or the first magnetic pole is arranged on the top surface, and the second magnetic pole is arranged on the bottom surface.

8. A magnetron crystal pulling apparatus as set forth in claim 1 wherein a heat exchanger is disposed within the single crystal furnace above the crucible, the magnetron assembly being connected to the heat exchanger.

9. The magnetron crystal pulling apparatus of claim 1, wherein a spacing between the inner wall of the annular magnet and the outer wall of the single crystal silicon rod comprises any one of 2-10 centimeters.

10. A magnetron crystal pulling apparatus as claimed in claim 1 wherein the magnetron assembly further comprises a cooling layer and a thermal insulation layer;

the cooling layer covers the annular magnet, the heat insulation layer covers the cooling layer, and a cooling medium is filled in the cooling layer.

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