CN217719177U

CN217719177U - Magnetic control single crystal pulling superconducting magnet and equipment

Info

Publication number: CN217719177U
Application number: CN202221222862.5U
Authority: CN
Inventors: 刘伟; 马鹏; 李超; 张弛; 韩志晨; 葛正福; 兰贤辉; 周涛; 杨战锋; 冯勇; 刘向宏; 张平祥
Original assignee: Western Superconducting Technologies Co Ltd
Current assignee: Western Superconducting Technologies Co Ltd
Priority date: 2022-05-19
Filing date: 2022-05-19
Publication date: 2022-11-01
Anticipated expiration: 2032-05-19

Abstract

The utility model discloses a single crystal superconducting magnet and equipment are drawn to magnetic control, the superconducting magnet includes: a superconducting coil; the superconducting switch is connected in parallel at two ends of the superconducting coil, the superconducting switch comprises a switch coil and a heater, the heater is used for heating the switch coil, the switch coil is made of superconducting materials, the switch coil is separated from a superconducting state when being heated to a temperature above a critical temperature, short circuit to the superconducting coil is removed, after a superconducting power supply inputs required current to the superconducting coil, the heater stops heating the switch coil, the switch coil is enabled to enter the superconducting state, and the switch coil and the superconducting coil enter a closed-loop working state. The utility model discloses introduce superconductive switch technique to avoided because power supply system is unstable and cut off the power supply suddenly, the magnet that leads to quenches and loses the condition in magnetic field, and because the magnetic field fluctuation that the superconductive power supply ripple arouses, its and the single crystal growing furnace heating member produce the electromagnetic force that changes, the single crystal growing furnace vibration problem that arouses.

Description

Magnetic control single crystal pulling superconducting magnet and equipment

Technical Field

The utility model relates to the technical field of semiconductor production equipment, in particular to a magnetic control single crystal pulling superconducting magnet and equipment.

Background

The high-purity monocrystalline silicon is widely applied to industries such as solar cells, integrated circuits, semiconductors and the like, is one of key materials of high and new technology industries such as photovoltaic power generation, electronic information and the like, and has an important strategic position in terms of energy, information and national safety. However, due to the high design technical difficulty, the high processing and manufacturing difficulty, the high cost and risk and the like of a large-scale superconducting strong magnet device, which is a core component of the magnetic pulling single crystal technology, the related basic research and the technology accumulation are lacked in China, and the technology is completely monopolized by the countries of the day, the America, the Germany and the like.

According to the research and study of the existing documents, the regional and monopolistic property of the processing and preparation of the monocrystalline silicon in the field of the superconducting magnet for magnetically controlling and pulling the monocrystalline silicon at present leads the overseas research and development unit to be mainly Japanese enterprises. The related research of domestic monocrystalline silicon is coming up after years of accumulation and development. In recent years, there have been protection applications in related patents, such as 2013, li Chao, guo, etc., and publication No. of "an MgB2 superconducting magnet for magnetically controlled czochralski single crystal: CN103106994a,2019, shang Hongming, fu Linjian, etc., to provide "a superconducting magnet and a magnetron czochralski single crystal apparatus", publication no: CN110136915a, however, the above utility model only describes the superconducting magnet itself, and does not consider the integration problem in the use from the perspective of combining the single crystal furnace and the superconducting magnet.

At present, the utility model provides a magnetic control draws single crystal superconducting magnet all loads at superconducting coil both ends for the power all always, open the ring operation mode promptly, this kind of operation mode is when the proruption outage condition, the magnet can lead to the quench because the outage suddenly, appear when the magnet after the quench, the coil will be heated by the energy that magnet self stored, lead to the temperature to rise, cooling down again and exciting needs dozens of hours or even longer time, it is great to the inevitable influence of the single crystal material quality of just being produced, also can directly lead to the scheduling problem of burning out of superconducting magnet simultaneously.

Simultaneously, above utility model most only has involved superconducting magnet itself, do not combine superconducting magnet and single crystal growing furnace to integrate, integrated back because superconducting power supply's ripple can lead to superconducting magnet's operating current I to produce the change of I delta I, through the amplification of the great number of turns of superconducting coil (> 1 ten thousand circles), delta B's fluctuation can appear in the magnetic field of magnet, the magnetic field of change and the heating member effect of single crystal growing furnace, produce the electromagnetic lorentz force that changes, thereby arouse the holistic vibration of single crystal growing furnace, finally influence the growth quality of single crystal.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a single crystal superconducting magnet is drawn to magnetic control and equipment for solve among the prior art because the power unstability leads to superconducting magnet outage quench or leads to the problem of single crystal growing furnace vibration.

In one aspect, an embodiment of the present invention provides a single crystal superconducting magnet is drawn to magnetic control, including:

a superconducting coil;

the superconducting switch is connected in parallel at two ends of the superconducting coil, and the superconducting switch and the superconducting coil are connected in parallel and then are used for being connected with a superconducting power supply;

the superconducting switch comprises a switch coil and a heater, the heater is used for heating the switch coil, the switch coil is made of superconducting materials, the switch coil is separated from a superconducting state when being heated to be above a critical temperature, short circuit to the superconducting coil is removed, after a superconducting power supply inputs required current to the superconducting coil, the heater stops heating the switch coil, the switch coil is enabled to be in the superconducting state, and the switch coil and the superconducting coil are enabled to be in a closed-loop working state.

On the other hand, the embodiment of the utility model provides a single crystal equipment is drawn to magnetic control, draw single crystal superconducting magnet including single crystal growing furnace and foretell one kind, superconducting magnet is ring columnar structure, and the single crystal growing furnace setting is in superconducting magnet's axle center position.

The utility model provides a single crystal superconducting magnet is drawn to magnetic control and equipment has following advantage:

under the special conditions required by the growth of the superconducting magnet and the single crystal, a superconducting switch (PCS) technology is introduced, so that the problems of magnet quenching and magnetic field loss caused by unstable power supply system and sudden power failure and single crystal furnace vibration caused by the fact that the magnetic field fluctuation and a heating body of the single crystal furnace generate variable electromagnetic force due to superconducting power supply ripple are solved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic view of an overall structure of a single crystal pulling apparatus with magnetic control according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a single crystal pulling apparatus with magnetic control according to an embodiment of the present invention;

fig. 3 is a half sectional view of a magnetic control single crystal pulling superconducting magnet according to an embodiment of the present invention;

FIG. 4 is a structural view of a heating body in a single crystal furnace employed in the prior art;

FIG. 5 is a force diagram of a heating body of the single crystal furnace of FIG. 4;

FIG. 6 is a diagram showing the structure and force of a heating body in a single crystal furnace according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a superconducting magnet using a saddle-shaped superconducting coil according to an embodiment of the present invention;

fig. 8 is a schematic diagram illustrating an operation of a superconducting coil inside a superconducting magnet according to an embodiment of the present invention;

fig. 9 is a schematic view illustrating an operation flow of a superconducting switch of a superconducting magnet according to an embodiment of the present invention;

fig. 10 is a schematic diagram of current conditions of a superconducting magnet provided by an embodiment of the present invention in different operation modes.

The reference numbers illustrate: 1. a superconducting magnet; 101. a refrigerator; 102. a superconducting coil; 103. cooling the screen; 104. A magnetic shield iron yoke; 105. a vacuum dewar inner cylinder; 2. a single crystal furnace; 201. a cavity; 202. a heating body; 202-1, 202-2 heating electrodes; 203. a crucible; 204. a rotating shaft; 3. single crystal silicon rods and accessories; 301. A single crystal silicon rod; 302. carrying out crystal seeding; 303. pulling the wire; 304. a polycrystalline silicon solution; 4. a superconducting switch; 401. A switching coil; 402. a heater; 5. a superconducting power supply; 6. supply circuit breaker.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Fig. 1-10 are schematic structural diagrams of a magnetic control single crystal pulling superconducting magnet and an apparatus provided in an embodiment of the present invention. The embodiment of the utility model provides a single crystal superconducting magnet is drawn to magnetic control, include:

a superconducting coil 102;

the superconducting switch 4 is connected in parallel at two ends of the superconducting coil 102, and the superconducting switch 4 is connected in parallel with the superconducting coil 102 and then is used for being connected with the superconducting power supply 5;

the superconducting switch 4 includes a switch coil 401 and a heater 402, the heater 402 is used for heating the switch coil 401, the switch coil 401 is made of superconducting materials, the switch coil 401 is separated from a superconducting state when being heated to a temperature above a critical temperature, short circuit to the superconducting coil 102 is removed, after the superconducting power supply 5 inputs required current to the superconducting coil 102, the heater 402 stops heating the switch coil 401, the switch coil 401 is enabled to enter the superconducting state, and the switch coil 401 and the superconducting coil 102 enter a closed-loop working state.

Illustratively, the superconducting magnet 1 further includes: the cold screen 103, the superconducting coil 102 and the superconducting switch 4 are all arranged inside the cold screen 103; and a refrigerator 101 for cooling the inside of the cold screen 103.

In an embodiment of the present invention, the refrigerator 101 may be a G-M refrigerator, which cools a cooling medium, such as liquid helium, and then inputs the cooled medium into the cold shield 103 to keep the superconducting coil 102 below its critical temperature Tc, so as to maintain a superconducting state.

The superconducting magnet 1 further includes: the magnetic shielding iron yoke 104 and the cold shield 103 are in a hollow circular cylindrical structure, and the magnetic shielding iron yoke 104 is arranged on one side of the outside of the cold shield 103, which is far away from the axis.

In the real-time embodiment of the present invention, the magnetic shielding yoke 104 is made of ferromagnetic metal, such as iron, cobalt, nickel, and alloys thereof, which can prevent the strong magnetic field generated by the operation of the superconducting coil 102 from leaking outwards, and threatens personnel and other equipment.

The superconducting magnet 1 further includes: and the vacuum Dewar inner cylinder 105 is arranged on one side, close to the axis, of the outer part of the cold shield 103, the vacuum Dewar inner cylinder 105 is connected with two ends of the magnetic shielding iron yoke 104, and the space between the vacuum Dewar inner cylinder 105 and the magnetic shielding iron yoke 104 is in a vacuum state.

In the embodiment of the present invention, the vacuum dewar inner tube 105 is connected to the magnetic shielding yoke 104 to form a sealed space inside, and the cold shield 103 is located in the sealed space. After the vacuum is evacuated from the sealed space by the vacuum device, the heat load in the cold shield 103 due to the heat convection can be reduced.

As shown in fig. 3 and 7, the superconducting coils 102 may have a circular or saddle-shaped structure, and when the circular structure is adopted, the number of the superconducting coils 102 is four, and the four circular superconducting coils 102 are symmetrically arranged with the axis of the superconducting magnet as a symmetry axis. When the saddle-shaped structure is adopted, the number of the superconducting coils 102 is two, and the two saddle-shaped superconducting coils 102 are symmetrically arranged by taking the axis of the superconducting magnet as a symmetry axis.

The utility model discloses well magnetic control draws single crystal superconducting magnet's working process as follows:

when the superconducting magnet 1 is installed, firstly, a vacuum unit is used for vacuumizing a sealed space between the superconducting magnet 1, specifically, the magnetic shielding iron yoke 104 and the vacuum Dewar inner cylinder 105, and when the vacuum degree reaches 10^-2When the temperature of the superconducting coil 102 in the superconducting magnet 1 is lower than the critical temperature Tc of the superconducting wire, the superconducting coil 102 enters a superconducting state and has the power-on excitation capability.

Next, as shown in the superconducting switch operation mode of fig. 9, first, the heater 402 inside the switching coil 401 is energized so that the temperature of the switching coil 401 of the superconducting switch 4 becomes higher than the critical temperature Tc thereof, and at this time, the switching coil 401 enters a resistive state, and the state in which the superconducting coil 102 is short-circuited by the switching coil 401 is released, and the current input from the superconducting power supply 5 starts to flow through the superconducting coil 102. And then, according to the drawing process requirement of the monocrystalline silicon, setting a target current of a superconducting power supply 5, closing a power supply loop breaker 6, starting the superconducting power supply 5, electrifying the superconducting magnet 1, stopping electrifying the heater 402 after the target current is reached, and after the temperature of the switch coil 401 is reduced to Tc, setting the current of the superconducting power supply 5 to be 0 and carrying out power-off. At this time, since the superconducting coil 102 enters a superconducting state, during the process of powering down the superconducting power supply 5, the superconducting coil 102 is short-circuited by the switching coil 401, and the superconducting coil 102 and the switching coil 401 form a closed loop, so that the internal current of the superconducting magnet 1 will operate independently of the superconducting power supply 5.

Therefore, the operation mode of the superconducting magnet 1 in closed-loop operation is different from the operation mode of the magnet directly powered by the superconducting power supply, and has three main advantages: 1. the superconducting magnet can work independently of the superconducting power supply, so that the superconducting magnet is not influenced by the quality of the superconducting power supply, namely a high-cost power supply with ultrahigh precision and stability is not needed, and the cost of the superconducting magnet is reduced; 2. because the superconducting magnet can work independently of the superconducting power supply, the superconducting power supply has problems in power supply, and the superconducting magnet cannot be quenched; 3. compared with a superconducting magnet in which a superconducting power supply is connected in series in a power supply loop for direct power supply all the time, when the superconducting power supply generates ripple waves, the current of the whole superconducting coil of the superconducting magnet changes along with the current of the superconducting power supply to passively generate changes of +/-delta I, as shown in the stable situation of the current under different operation modes of the superconducting magnet in fig. 10, through the amplification of a large number of turns (usually thousands of turns) of the superconducting coil, the fluctuation of delta B can occur in the magnetic field of the superconducting magnet, and the changed magnetic field acts on a heating body of the single crystal furnace to generate changed Lorentz force, so that the vibration of the whole single crystal furnace is caused, and the growth quality of the single crystal is finally influenced. While the superconducting magnet in closed-loop operation, as shown in fig. 10, has very stable operation current, if necessary, the magnetic field can be changed according to the steps shown in fig. 9, so as to realize the magnetic field change of the magnet.

The embodiment of the utility model provides a single crystal equipment is drawn to magnetic control still, draw single crystal superconducting magnet including single crystal growing furnace 2 and foretell magnetic control, the superconducting magnet is ring columnar structure, and single crystal growing furnace 2 sets up the axle center position at the superconducting magnet.

Illustratively, the above-mentioned magnetron crystal pulling apparatus is used for holding and producing the polysilicon rod and the attachment 3. The single crystal furnace 2 includes: a cavity 201; the crucible 203 is arranged inside the cavity 201 and used for containing polycrystalline silicon; and a heating body 202 arranged inside the cavity 201, wherein the heating body 202 is arranged around the crucible 203, and the heating body 202 is used for heating the polycrystalline silicon in the crucible 203.

In an embodiment of the present invention, the crucible 203 may be a quartz crucible to withstand the high temperature of the molten polysilicon.

The heating body 202 includes a heating coil and heating electrodes 202-1 and 202-2, the heating electrodes are respectively connected to both ends of the heating coil, and the heating coil is of a square zigzag structure.

As shown in fig. 4 and 5, the conventional heating body 202 is of a spiral structure, and the current directions on a certain section of the heating body 202 are opposite, so that when the power supply is rippled, the directions of lorentz forces induced by the heating body 202 are also opposite, and the heating body 202 is subjected to a large torque, so that the heating body 202 is easy to vibrate. And the utility model discloses improve the heating coil of heating member 202 for the square zigzag, make the electric current opposite direction of two adjacent parts of heating coil, therefore under the lorentz force effect, the electromagnetic force of two adjacent parts offsets each other, therefore whole new heating member can not be like the heating member that adopts spiral structure to heating member geometric center forms a great torque, has improved the stability of heating member 202.

The single crystal furnace 2 further includes: the rotating shaft 204, the cavity 201 is rotatably arranged on the rotating shaft 204.

In the embodiment of the present invention, the height of the single crystal furnace 2 can be adjusted by the motor at the lower part of the single crystal furnace 2.

The operation process of the magnetic control single crystal pulling equipment of the utility model is as follows:

when the installation of the single crystal furnace 2 is completed, polycrystalline silicon is added into the crucible 203, and after other conditions are ready, the heating body 202 is turned on to heat the polycrystalline silicon to melt it. In the absence of a magnetic field, the level of the polycrystalline silicon solution 304 in the crucible 203 fluctuates, and single crystal pulling cannot be performed. When the magnetic field of the superconducting magnet 1 runs at a required value of single crystal pulling, the sub-crystal 302 is placed on the upper part of the liquid level of the molten polycrystalline silicon in the crucible 203 through the pulling wire 303 and is slowly pulled to realize seeding, the diameter of the single crystal silicon rod 301 is controlled through the rotating speed of the rotating shaft 204, and finally, the production and the manufacture of the single crystal silicon are completed according to the pulling process.

While the preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A magnetically controlled single crystal pulling superconducting magnet, comprising:

a superconducting coil (102);

the superconducting switch (4) is connected in parallel at two ends of the superconducting coil (102), and the superconducting switch (4) and the superconducting coil (102) are connected in parallel and then are used for being connected with a superconducting power supply (5);

the superconducting switch (4) comprises a switch coil (401) and a heater (402), the heater (402) is used for heating the switch coil (401), the switch coil (401) is made of superconducting materials, the switch coil (401) is separated from a superconducting state when being heated to a critical temperature or above, short circuit of the superconducting coil (102) is removed, after a superconducting power supply (5) inputs required current to the superconducting coil (102), the heater (402) stops heating the switch coil (401), the switch coil (401) is made to enter the superconducting state, and the switch coil (401) and the superconducting coil (102) are made to enter a closed-loop working state.

2. A magnetron pulled single crystal superconducting magnet as claimed in claim 1 further comprising:

the cold screen (103), the superconducting coil (102) and the superconducting switch (4) are both arranged inside the cold screen (103);

and a refrigerator (101) for cooling the inside of the cold screen (103).

3. A magnetron pulled single crystal superconducting magnet as claimed in claim 2 further comprising:

magnetic shield yoke (104), cold screen (103) are hollow ring column structure, magnetic shield yoke (104) set up cold screen (103) outside one side of keeping away from the axle center.

4. A magnetron pulled single crystal superconducting magnet as claimed in claim 3 further comprising:

barrel (105) in the vacuum dewar, set up in cold shield (103) outside is close to one side of axle center, just barrel (105) in the vacuum dewar with the both ends of magnetic shield yoke (104) are connected, the space between barrel (105) and magnetic shield yoke (104) is vacuum state in the vacuum dewar.

5. A magnetically controlled single crystal pulling superconducting magnet according to claim 1, wherein the number of the superconducting coils (102) is four, and the superconducting coils (102) are circular, and the four circular superconducting coils (102) are arranged symmetrically with respect to the axis of the superconducting magnet as a symmetry axis.

6. A magnetically controlled single crystal pulling superconducting magnet according to claim 1, wherein the number of the superconducting coils (102) is two, and the superconducting coils (102) are saddle-shaped, and the two saddle-shaped superconducting coils (102) are arranged symmetrically with respect to the axis of the superconducting magnet as the symmetry axis.

7. A magnetic control single crystal pulling device is characterized by comprising a single crystal furnace (2) and a magnetic control single crystal pulling superconducting magnet according to any one of claims 1 to 6, wherein the superconducting magnet is of a circular ring cylindrical structure, and the single crystal furnace (2) is arranged at the axis position of the superconducting magnet.

8. A magnetron pulling single crystal apparatus as claimed in claim 7, characterized in that the single crystal furnace (2) comprises:

a cavity (201);

the crucible (203) is arranged inside the cavity (201) and is used for containing polycrystalline silicon;

the heating body (202) is arranged inside the cavity (201), the heating body (202) is arranged around the crucible (203), and the heating body (202) is used for heating the polycrystalline silicon in the crucible (203).

9. The magnetron single crystal pulling apparatus as defined in claim 8, wherein the heating body (202) includes a heating coil and heating electrodes, the heating electrodes being connected to both ends of the heating coil, respectively, the heating coil having a zigzag structure.

10. A magnetron pulling single crystal apparatus as claimed in claim 8, characterized in that the single crystal furnace (2) further comprises:

the rotating shaft (204), the cavity (201) is rotationally arranged on the rotating shaft (204).