Thermal field device and single crystal furnace

Abstract

The utility model discloses a thermal field device, and belongs to the technical field of thermal fields. Comprising a bottom thermal insulation cylinder and a gas guide cylinder, the gas guide cylinder is sleeved with the thermal insulation cylinder, and the gas guide cylinder is arranged on the lower portion of the thermal insulation cylinder; a first airflow channel is formed between the air guide cylinder and the heat preservation cylinder. In the embodiment of the invention, the arrangement of the first airflow channel plays a role in guiding airflow in the thermal field device, so that the airflow with volatile substances flows to the through hole along with the first airflow channel until the airflow flows out of the thermal field device, and therefore, the thermal field device has the beneficial effect of preventing the airflow from disorderly flowing in the thermal field device to cause erosion corrosion to the thermal field device.

Description

Technical Field

[0001] The present application belongs to the field of thermal field technology, and specifically relates to a thermal field device and a single crystal furnace. Background Art

[0002] As the promotion of large-size silicon wafers requires a larger thermal field, the cost of graphite parts in the thermal field increases, and at the same time, higher requirements are placed on the stability of crystal pulling. Reducing the cost of pulling large-size CZ-pulled single crystal silicon is a boost to the entire industry chain and will drive the industry forward quickly and steadily.

[0003] In the prior art, the main heater, bottom heater and crucible rib in the thermal field are important components of the thermal field cost.

[0004] However, the airflow in the hot field drives volatiles to pass through the heater, insulation tube, crucible side, bottom graphite parts and bottom insulation parts. The volatiles will scour and corrode the hot field parts. In severe cases, the heater may ignite and crack, making it impossible to pull crystals, or even cause production accidents. Volatile substances will accelerate the pulverization rate of graphite parts and insulation parts in the hot field. At the same time, heat is directly radiated to the exhaust holes, causing heat loss, temperature instability, and thus unstable crystal pulling. Utility Model Content

[0005] The purpose of the embodiments of the present application is to provide a thermal field device and a single crystal furnace, which can at least solve the problem in the prior art that the airflow of the thermal field device drives volatiles to erode and corrode the thermal field components.

[0006] In order to solve the above technical problems, this application is implemented as follows:

[0007] An embodiment of the present application provides a thermal field device, including a heat preservation tube and an air guide tube, wherein the heat preservation tube is sleeved on the outer periphery of the air guide tube, and the air guide tube is arranged at the lower part of the heat preservation tube; a first air flow channel is formed between the air guide tube and the heat preservation tube.

[0008] Specifically, in practical applications, the crystal pulling process is completed in a thermal field device, and volatiles with corrosive effects are generated during the crystal pulling process. The airflow in the thermal field will drive the volatiles to scour and corrode many thermal field components in the thermal field. For example, the scouring and corroding of the bottom insulation component will increase the powdering rate of the bottom insulation component, and the scouring and corroding of the bottom heater will cause the bottom heater to fail when it is severely damaged. In an embodiment of the present application, the insulation cylinder is sleeved on the periphery of the gas guide cylinder, and the gas guide cylinder is arranged at the lower part of the insulation cylinder. A first airflow channel is formed between the gas guide cylinder and the insulation cylinder. The setting of the first airflow channel plays a role in guiding the airflow in the thermal field device. During the crystal pulling process, the thermal field device is evacuated through the through hole at the bottom of the single crystal furnace body, so that the airflow with volatile substances flows to the through hole along the first airflow channel until it flows out of the thermal field device through the through hole, thereby avoiding the airflow with volatile substances from scouring and surrounding the thermal field components in the thermal field, such as the bottom heater and the bottom insulation component. The insulation cylinder is used to ensure the temperature in the thermal field device to provide a suitable temperature for crystal pulling; the gas guide cylinder can be arranged around the bottom heater to avoid the airflow containing volatile substances from scouring the bottom heater; the gas guide cylinder can also be arranged around the bottom insulation component to avoid the airflow containing volatile substances from scouring the bottom insulation component.

[0009] An embodiment of the present application also provides a single crystal furnace, comprising the thermal field device as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram of the structure of the thermal field device in the embodiment of the present application;

[0011] Figure 2 It is a schematic diagram of the structure of the air guide cylinder in the embodiment of the present application;

[0012] Figure 3 It is a cross-sectional schematic diagram of the air guide cylinder in the embodiment of the present application.

[0013] Description of reference numerals:

[0014] 10. furnace body; 11. through hole; 20. insulation tube; 30. bottom insulation member; 41. air guide tube; 42. air guide shell; 421. shielding plate; 4211. first hole; 4212. first boss; 422. connecting ring; 423. air guide plate; 4231. second hole; 4232. second boss; 50. crucible; 60. bottom heater; 70. air barrier tube; 80. main heater; 90. exhaust hole. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0016] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0017] The thermal field device provided in the embodiment of the present application is described in detail below through specific embodiments and application scenarios in conjunction with the accompanying drawings.

[0018] See also Figures 1 to 3 An embodiment of the present application provides a thermal field device, including a heat preservation tube 20 and an air guide tube 41, the heat preservation tube 20 is sleeved on the outer periphery of the air guide tube 41, and the air guide tube 41 is arranged at the lower part of the heat preservation tube 20; a first air flow channel is formed between the air guide tube 41 and the heat preservation tube 20.

[0019] Specifically, in actual applications, the crystal pulling process is completed in a thermal field device, and corrosive volatiles are generated during the crystal pulling process. The airflow in the thermal field will drive the volatiles to scour and corrode many thermal field components in the thermal field. For example, the scouring and corrosion of the bottom insulation component 30 will increase the powdering rate of the bottom insulation component 30, and the scouring and corrosion of the bottom heater 60 will cause the bottom heater 60 to be severely damaged and cause failure. In the embodiment of the present application, the insulation cylinder 20 is sleeved on the outer periphery of the air guide cylinder 41, and the air guide cylinder 41 is arranged at the lower part of the insulation cylinder 20, and a first air flow channel is formed between the air guide cylinder 41 and the insulation cylinder 20. The setting of the first air flow channel plays a role in guiding the air flow in the thermal field device. During the crystal pulling process, the thermal field device is evacuated through the through hole 11 at the bottom of the single crystal furnace body 10, so that the air flow carrying volatile substances flows toward the through hole 11 along the first air flow channel until it flows out of the thermal field device through the through hole 11, thereby preventing the air flow carrying volatile substances from scouring around the thermal field components in the thermal field, such as the bottom heater 60 and the bottom insulation component 30. The insulation cylinder 20 is provided to ensure the temperature in the thermal field device to provide a suitable temperature for crystal pulling; the air guide cylinder 41 can be arranged around the bottom heater 60 to avoid the airflow containing volatile substances from scouring the bottom heater 60; the air guide cylinder 41 can also be arranged around the bottom insulation component 30 to avoid the airflow containing volatile substances from scouring the bottom insulation component 30.

[0020] It can be understood that the setting of the first air flow channel plays a role in guiding the air flow in the thermal field device. The air flow carrying volatile substances flows along the first air flow channel to the through hole 11 until it flows out of the thermal field device, thereby having the beneficial effect of avoiding the disordered flow of the air flow in the thermal field device and causing erosion and corrosion of the thermal field parts.

[0021] It should be noted that the bottom insulation component 30 can be a bottom soft felt or a bottom solid felt, and this embodiment does not impose any limitation on this.

[0022] Furthermore, the above arrangement can protect the bottom insulation component 30 in the thermal field component from erosion and corrosion, thereby improving the insulation effect of the bottom insulation component 30, preventing heat from dissipating from the through hole 11, and improving the stability of crystal pulling.

[0023] Specifically, the insulation tube 20 may include an upper insulation tube, a middle insulation tube and a lower insulation tube, or the insulation tube 20 may include an upper insulation tube and a lower insulation tube, or even the insulation tube 20 may be an integrated structure, and this embodiment does not make any limitation to this. In addition, the insulation tube 20 may be a thin-walled tube with a carbon-carbon or graphite lining and a soft felt wrapped around the outside, or may be a solid felt insulation tube, and this embodiment does not make any limitation to this.

[0024] Optionally, in the embodiment of the present application, there is a first preset interval between the air guide cylinder 41 and the heat preservation cylinder 20 along the radial direction of the heat preservation cylinder 20, and the first preset interval is A, where A≥20 mm.

[0025] In the embodiment of the present application, it can be understood that the first preset interval is the width of the first airflow channel. The setting of the first preset interval provides a space for the airflow carrying volatile substances to flow freely, which has the beneficial effect of increasing the flow rate of the airflow carrying volatile substances in the first airflow channel.

[0026] Specifically, as the thermal field device is evacuated, when the width of the first airflow channel is less than 20 mm, the airflow with volatile substances may have a low flow rate due to the small size of the airflow channel, resulting in a longer residence time in the thermal field device, and may overflow from the first airflow channel to cause erosion and corrosion to the thermal field components. Therefore, setting the width of the first airflow channel of the thermal field device to be greater than or equal to 20 mm has the beneficial effect of facilitating the airflow with volatile substances to quickly flow out of the thermal field device.

[0027] Optionally, in the embodiment of the present application, there is a second preset interval between the air guide tube 41 and the bottom heater 60 in the heat field along the radial direction of the thermal insulation tube 20, and the second preset interval is B, where B≥20 mm.

[0028] In the embodiment of the present application, the second preset interval is set to protect the gas guide tube 41 from being damaged by the heat radiated by the bottom heater 60. Specifically, in actual applications, the bottom heater 60 needs to radiate heat in the thermal field device to achieve a temperature environment suitable for crystal pulling. If the second preset interval is less than 20 mm, the distance between the gas guide tube 41 and the bottom heater 60 is too close, and the maximum temperature that the material of the gas guide tube 41 can withstand is too low. Therefore, there is a risk that the gas guide tube 41 is damaged by the heat radiated by the bottom heater 60, and then, the gas guide tube 41 and the bottom heater 60 have a second preset interval along the axial direction perpendicular to the thermal field device.

[0029] Furthermore, in practical applications, the second preset interval can also be determined according to the specifications of the bottom heater 60 and the actual situation of the thermal field device. For example, when the gas guide tube 41 is made of carbon-carbon material, the maximum temperature that the gas guide tube 41 can withstand is higher, and the second preset interval can also be reduced accordingly.

[0030] Optionally, in the embodiment of the present application, along the radial direction of the heat preservation cylinder 20, there is at least a third preset interval between the gas guide cylinder 41 and the outer surface of the crucible 50 in the heat field, and the third preset interval is C, where C≥20mm.

[0031] In the embodiment of the present application, the third preset interval is set to protect the gas guide cylinder 41 and avoid damage caused by the heat radiated by the crucible 50. Specifically, in practical applications, the silicon material grows in the crucible 50, and the temperature of the crucible 50 is at least the melting point of the silicon material. If the third preset interval is less than 20 mm, there is a risk that the gas guide cylinder 41 is damaged by the heat radiated by the crucible 50. Therefore, there is a second preset interval of at least 20 mm between the gas guide cylinder 41 and the crucible 50 along the axial direction perpendicular to the thermal field device.

[0032] Optionally, in an embodiment of the present application, the thermal field device also includes an air guide shell 42, which is arranged at the bottom of the air guide cylinder 41, and the air guide shell 42 is connected to the air guide cylinder 41, and a second air flow channel is arranged in the air guide shell 42; the second air flow channel is connected to the first air flow channel, and is used to change the flow direction of the air flow.

[0033] In the embodiment of the present application, the air guide housing 42 is disposed at the bottom of the air guide cylinder 41, and is used to receive the airflow with volatile substances flowing through the first airflow channel. A second airflow channel is disposed in the air guide housing 42, and the second airflow channel is connected to the first airflow channel, and the second airflow channel is connected to the through hole 11 of the furnace body 10. In actual application, the airflow with volatile substances flows through the first airflow channel, the second airflow channel and the through hole 11 in sequence and flows out of the thermal field device.

[0034] In the embodiment of the present application, the airflow carrying volatile substances can flow through the first airflow channel and the second airflow channel as little as possible without flowing in other spaces in the thermal field device, thereby having the beneficial effect of reducing corrosion damage to other thermal field components in the thermal field device.

[0035] Optionally, along the axial direction of the heat preservation tube, the air guide housing 42 is disposed between the bottom heater 60 in the heat field and the bottom of the furnace body 10 , or the air guide housing 42 is disposed between the bottom heat preservation member 30 in the heat field and the bottom of the furnace body 10 .

[0036] In the embodiment of the present application, the air guide housing 42 may be a disc-shaped structure, and part of the disc-shaped structure is disposed between the bottom heater 60 and the bottom of the furnace body 10, or between the bottom insulation member 30 in the heat field and the bottom of the furnace body 10. The air guide housing 42 is disposed between the bottom insulation member 30 and the bottom of the furnace body 10, which also has the beneficial effect of isolating the bottom insulation member 30 from the furnace body 10. In addition, in the axial direction of the insulation cylinder 20, the air guide housing 42 may also be at least partially disposed inside the bottom insulation member 30 as required, so as to improve the insulation performance of the bottom insulation member and the air guide housing 42.

[0037] Optionally, in an embodiment of the present application, the air guide housing 42 includes a baffle plate 421, a connecting ring 422 and an air guide plate 423, the baffle plate 421 is arranged on the upper side of the connecting ring 422 close to the air guide cylinder 41, and the air guide plate 423 is arranged on the lower side of the connecting ring 422 away from the air guide cylinder 41; a second air flow channel is formed between the baffle plate 421 and the air guide plate 423.

[0038] In the embodiment of the present application, the shielding plate 421 and the air guide plate 423 are arranged to form a second airflow channel to guide the airflow with volatile substances. The connection ring 422 is arranged to connect the shielding plate 421 and the air guide plate 423. The shielding plate 421 is arranged to connect with the air guide cylinder 41, and at the same time, it also separates the possibility of the airflow with volatile substances from contacting the bottom insulation member 30. The air guide plate 423 is arranged on the lower side of the connection ring 422 away from the air guide cylinder 41, and is used to cooperate with the shielding plate 421 to form a second airflow channel.

[0039] Furthermore, the shielding plate 421 is provided with a first hole 4211, and the air guide plate 423 is provided with a second hole 4231. The first hole 4211 and the second hole 4231 are connected through a connecting ring 422. The connecting ring 422 has a preset height along the axial direction of the thermal field device, and the preset height is the width of the second air flow channel.

[0040] As an implementation method of this embodiment, the shielding plate 421 and the air guide plate 423 are parallel and coaxial to each other, and the diameter of the air guide plate 423 is larger than the diameter of the shielding plate 421. The shielding plate 421 is connected to the air guide tube 41, and the air guide plate 423 is close to the bottom of the furnace body 10 and connected to the insulation tube 20, so as to realize the setting of the first air flow channel between the air guide tube 41 and the insulation tube 20. Furthermore, the second air flow channel is connected to the first air flow channel, and the air flow with volatile substances enters the second air flow channel from the first air flow channel. Due to the setting of the shielding plate 421, the air flow with volatile substances does not or rarely passes through the bottom insulation part 30 or the bottom heater 60, and therefore, it will not cause erosion and corrosion to the bottom insulation part 30 or the bottom heater 60, which has the beneficial effect of protecting the bottom insulation part 30 from erosion and corrosion.

[0041] Specifically, the edge of the shielding plate 421 is provided with a first boss 4212, and the first boss 4212 is provided to realize the connection between the shielding plate 421 and the air guide cylinder 41. The air guide cylinder 41 and the first boss 4212 are clamped, and the shielding plate 421 and the air guide cylinder 41 are enclosed to form a protective space. The thermal field device also includes a crucible 50 and a bottom heater 60, and the bottom of the bottom heater 60 and the crucible 50 are arranged in the protective space. When the airflow with volatiles flows through the first airflow channel, the bottom of the bottom heater 60 and the crucible 50 have no contact or very little contact with the airflow with volatiles, so as to protect the bottom of the bottom heater 60 and the crucible 50 in the thermal field device, and have the beneficial effect of avoiding erosion and corrosion to the bottom of the bottom heater 60 and the crucible 50. However, erosion and corrosion are caused to the air guide cylinder 41. In actual application, when the air guide cylinder 41 needs to be replaced, the mutually clamped air guide cylinder 41 and the first boss 4212 have the beneficial effect of convenient disassembly and replacement.

[0042] Furthermore, the edge of the air guide plate 423 is provided with a second boss 4232, and the second boss 4232 is provided to realize the clamping connection between the air guide plate 423 and the heat preservation tube 20. The heat preservation tube 20 and the second boss 4232 are clamped, and the diameter of the air guide plate 423 is larger than the shielding plate 421, and the difference in radius between the air guide plate 423 and the shielding plate 421 is the width of the first air flow channel. Due to the clamping connection between the heat preservation tube 20 and the second boss 4232 and the clamping connection between the air guide tube 41 and the first boss 4212, the first air flow channel is formed, and the protection of the thermal field components arranged in the protection space is realized.

[0043] Furthermore, since the air guide plate 423 is also provided with an exhaust hole 90, and the first airflow channel and the second airflow channel are connected, the airflow carrying volatiles flows from the first airflow channel and the second airflow channel to the through hole 11, and finally flows out of the thermal field device. In the above process, the airflow carrying volatiles does not have excessive contact with the thermal field components in the thermal field device, such as the bottom insulation component 30, the bottom of the crucible 50 and the bottom heater 60, which has the beneficial effect of protecting the thermal field components from erosion and corrosion by the airflow carrying volatiles.

[0044] Optionally, in the embodiment of the present application, an exhaust hole 90 is opened on the air guide plate 423 ; the second air flow channel is connected with the through hole 11 of the furnace body 10 through the exhaust hole 90 .

[0045] In the embodiment of the present application, the exhaust hole 90 is provided to communicate with the through hole 11. In practical applications, the airflow with volatile substances flows into the second airflow channel, that is, flows between the shielding plate 421 and the air guide plate 423. Then, it flows into the through hole 11 of the furnace body 10 along the exhaust hole 90 provided on the air guide plate 423, and finally flows out of the furnace body 10. In the embodiment of the present application, the provision of the exhaust hole 90 has the beneficial effect of enabling the airflow with volatile substances to flow out of the thermal field device.

[0046] Optionally, in the embodiment of the present application, a groove is provided on the inner wall of the heat preservation tube 20; at least part of the main heater 80 is located in the groove. In this embodiment, the groove can also be understood as a step formed on the inner wall of the heat preservation tube 20.

[0047] In the embodiment of the present application, the groove is provided to provide a placement space for the main heater 80. In practical applications, at least part of the main heater 80 is located in the groove, and the provision of the groove has the beneficial effect of reducing the space occupied by the main heater 80 in the thermal field device. In addition, the lower side of the groove can also block the heat transfer from the main heater to the lower part of the thermal field, reduce the heating of the bottom of the crucible, reduce the corrosion of the quartz crucible, and thus reduce the oxygen content of the crystal.

[0048] It should be noted that the heat preservation tube 20 is provided with a connection hole, and the foot plate of the main heater 80 or the electrode connecting the foot plate is located in the connection hole to achieve electrical connection between the main heater 80 and the copper electrode at the bottom of the furnace body 10.

[0049] Optionally, in an embodiment of the present application, the thermal field device includes an air trap cylinder 70 , which is connected to the heat preservation cylinder 20 , and the air trap cylinder 70 is arranged on a side of the main heater 80 in the thermal field away from the heat preservation cylinder 20 .

[0050] In the embodiment of the present application, the air trap 70 is provided to protect the main heater 80 in the thermal field device, and to prevent the airflow containing volatile substances from eroding the main heater 80 and causing damage. In practical applications, the air trap 70 can serve as a barrier to isolate the main heater 80 in the thermal field in the groove, thereby isolating the main heater 80 from the thermal field environment and thus protecting the main heater 80, which has the beneficial effect of preventing the airflow containing volatile substances in the thermal field device from causing damage to the main heater 80.

[0051] Optionally, in the embodiment of the present application, there is a fourth preset interval between the air trap 70 and the crucible 50 of the thermal field device along the axial direction perpendicular to the thermal field device, and the fourth preset interval is D, where D≥20 mm.

[0052] In the embodiment of the present application, the fourth preset interval is set to provide a space for the airflow containing volatiles to flow freely, which has the beneficial effect of increasing the flow rate of the airflow containing volatiles between the air trap 70 and the crucible 50 of the thermal field device.

[0053] Furthermore, with the thermal field device as described above, the thermal field components set in the thermal field environment can be protected by providing the air guide tube 41 and the air barrier tube 70. The thermal field components include but are not limited to the main heater 80, the bottom heater 60 and the bottom insulation component 30. Specifically, the airflow with volatiles generated in the thermal field can flow through the guide of the fourth preset interval, thereby avoiding erosion and corrosion of the main heater 80. Since the fourth preset interval is consistent with the direction of the first airflow channel, and a through hole 11 connected to the outside is provided at the bottom of the furnace body 10, the airflow naturally flows to the first airflow channel after flowing out of the fourth preset interval, and the airflow with volatiles can flow through the guide of the first airflow channel, thereby avoiding erosion and corrosion of the bottom heater 60 and part of the insulation component. Furthermore, since the second airflow channel is connected to the first airflow channel, and the air guide plate 423 is provided with an exhaust hole 90 that is connected to the through hole 11, the airflow with volatiles naturally flows through the second airflow channel and then flows out of the thermal field device from the through hole 11, which has the beneficial effect of avoiding erosion and corrosion of the thermal field parts and reducing the cost of the thermal field device. In addition, in this embodiment, the first airflow channel intersects with the second airflow channel, avoiding heat from being radiated directly through the through hole 11 in the axial direction, thereby improving the thermal insulation performance of the thermal field.

[0054] Optionally, in an embodiment of the present application, a single crystal furnace is also provided, comprising the thermal field device as described above.

[0055] In the embodiment of the present application, the single crystal furnace having the thermal field device as described above is provided with an air guide tube 41 and a heat preservation tube 20, and a first air flow channel is formed between the air guide tube 41 and the heat preservation tube 20. The first air flow channel plays a role of guiding the air flow in the thermal field device. The air flow carrying volatile substances flows toward the through hole 11 along the first air flow channel until it flows out of the thermal field device and flows out of the single crystal furnace, thereby having the beneficial effect of avoiding erosion and corrosion of the thermal field components caused by disorderly flow of air flow in the single crystal furnace.

[0056] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0057] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A thermal field device, characterized in that: The invention comprises a heat-insulating cylinder (20) and an air guide cylinder (41); the heat-insulating cylinder (20) is sleeved on the outer periphery of the air guide cylinder (41), and the air guide cylinder (41) is arranged at the lower part of the heat-insulating cylinder (20); and a first air flow channel is formed between the air guide cylinder (41) and the heat-insulating cylinder (20).

2. The thermal field device according to claim 1, characterized in that: There is a first preset interval between the air guide cylinder (41) and the heat insulation cylinder (20) along the radial direction of the heat insulation cylinder (20), and the first preset interval is A, where A≥20 mm.

3. The thermal field device according to claim 1, characterized in that: There is a second preset interval between the air guide cylinder (41) and the bottom heater (60) in the heat field along the radial direction of the heat preservation cylinder (20), and the second preset interval is B, where B≥20 mm.

4. The thermal field device according to claim 1, characterized in that: Along the radial direction of the heat-insulating cylinder (20), there is at least a third preset interval between the gas guide cylinder (41) and the outer surface of the crucible (50) in the heat field, and the third preset interval is C, where C≥20 mm.

5. The thermal field device according to any one of claims 1 to 4, characterized in that: The thermal field device further comprises an air guide housing (42), the air guide housing (42) being arranged at the bottom of the air guide cylinder (41), the air guide housing (42) being connected to the air guide cylinder (41), and a second air flow channel being arranged in the air guide housing (42); the second air flow channel being in communication with the first air flow channel and being used for changing the flow direction of the air flow.

6. The thermal field device according to claim 5, characterized in that: Along the axial direction of the heat preservation tube, the air guide housing (42) is arranged between the bottom heater (60) in the heat field and the bottom of the furnace body, or the air guide housing (42) is arranged between the bottom heat preservation member (30) in the heat field and the bottom of the furnace body.

7. The thermal field device according to claim 5, characterized in that: The air guide housing (42) comprises a shielding plate (421), a connecting ring (422) and an air guide plate (423); the shielding plate (421) is arranged on the upper side of the connecting ring (422) close to the air guide cylinder (41); the air guide plate (423) is arranged on the lower side of the connecting ring (422) away from the air guide cylinder (41); the second air flow channel is formed between the shielding plate (421) and the air guide plate (423).

8. The thermal field device according to claim 7, characterized in that: An exhaust hole (90) is provided on the air guide plate (423); the second air flow channel is connected to the through hole of the furnace body through the exhaust hole (90).

9. The thermal field device according to claim 1, characterized in that: A groove is provided on the inner side wall of the heat preservation cylinder (20); at least a portion of the main heater (80) in the heat field is located in the groove.

10. The thermal field device according to claim 8, characterized in that: The thermal field device further comprises an air barrier cylinder (70), the air barrier cylinder (70) being connected to the thermal insulation cylinder (20), and the air barrier cylinder (70) being arranged on a side of a main heater (80) in the thermal field away from the thermal insulation cylinder (20).

11. The thermal field device according to claim 10, characterized in that: A fourth preset interval is provided between the gas barrier cylinder (70) and the crucible (50) in the thermal field device along the radial direction of the thermal insulation cylinder (20), and the fourth preset interval is D, wherein D≥20 mm.

12. A single crystal furnace, characterized in that: A thermal field device comprising any one of claims 1 to 11.

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