A heater and a single crystal furnace

Abstract

This application provides a heater and a single-crystal furnace. The heater includes: a first foot plate and a second foot plate disposed opposite to each other; two heating elements, one end of each heating element being connected to the first foot plate and the other end being connected to the second foot plate; the two heating elements are connected in parallel between the first foot plate and the second foot plate, and surround the first foot plate and the second foot plate to form a ring structure; and at least one connecting member connecting the two heating elements. The design of the connecting member in this application embodiment improves the structural strength and rigidity of the heater, thereby reducing the risk of deformation or even breakage of the heating elements during the use of the heater, and extending the overall service life of the heater.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic processing technology, specifically relating to a heater and a single crystal furnace. Background Technology

[0002] In a single crystal furnace, the heater, as a key thermal field component, is placed outside the crucible to provide heat for melting silicon. However, after prolonged use, the mechanical strength of the heater gradually decreases, leading to deformation or even breakage, thus shortening the overall service life of the heater. Summary of the Invention

[0003] This application aims to provide a heater and a single crystal furnace that at least partially solves the problem of heaters being prone to deformation or even breakage.

[0004] To solve the above-mentioned technical problems, this application is implemented as follows: In a first aspect, embodiments of this application provide a heater, the heater comprising: The first and second footplates are set relative to each other; Two heating elements, one end of which is connected to the first foot plate and the other end of which is connected to the second foot plate; the two heating elements are connected in parallel between the first foot plate and the second foot plate, and together with the first foot plate and the second foot plate, form a ring structure; And at least one connector, which connects the two heating elements.

[0005] Optionally, the connector is located between the first foot plate and the second foot plate, and the foot plate that is closer to the connector is the target foot plate, and the minimum distance between the target foot plate and the connector is greater than or equal to 15mm.

[0006] Optionally, the surface of the connector adjacent to the target foot plate is a first surface, which is either a plane or an arc-shaped surface; if the first surface is an arc-shaped surface, the arc-shaped surface is concave to the connector.

[0007] Optionally, from one end of the heating element to the other, the heating element includes a plurality of heating bodies connected in sequence, at least some of the heating bodies being connected to form a serpentine structure; the minimum cross-sectional area of ​​the plurality of heating bodies is a first cross-sectional area, the minimum cross-sectional area of ​​the connecting member is a second cross-sectional area, and the second cross-sectional area is greater than or equal to the first cross-sectional area.

[0008] Optionally, the connector and at least one of the heating elements are integrally formed.

[0009] Optionally, the two heating elements are a first heating element and a second heating element; a plurality of connecting elements are sequentially spaced between the first heating element and the second heating element, and the plurality of connecting elements are connected in parallel.

[0010] Optionally, the resistance of the first heating element between two adjacent connecting members is R1, and the resistance of the second heating element between two adjacent connecting members is R2; Among them, |R1-R2| / R2*100%≤10% is satisfied.

[0011] Optionally, the two heating elements are a first heating element and a second heating element; the resistance of the first heating element between the first foot plate and the connecting member adjacent to the first foot plate is R11, and the resistance of the second heating element between the first foot plate and the connecting member adjacent to the first foot plate is R21; wherein, |R11-R21| / R21*100%≤10%; and / or, The resistance of the first heating element between the second foot plate and the connecting member adjacent to the second foot plate is R12, and the resistance of the second heating element between the first foot plate and the connecting member adjacent to the first foot plate is R22; wherein, |R12-R22| / R22*100%≤10%.

[0012] Optionally, R1=R2, R11=R21, R12=R22.

[0013] Optionally, the two heating elements are symmetrically arranged between the first foot plate and the second foot plate.

[0014] Optionally, the first heating element includes a first heating portion and a second heating portion arranged symmetrically on the axis; the second heating element includes a third heating portion and a fourth heating portion arranged symmetrically on the axis. One end of the first heating element and one end of the third heating element are connected to the first foot plate; one end of the second heating element and one end of the fourth heating element are connected to the second foot plate; The connecting member is provided between the first heating part and the third heating part; and / or, the connecting member is provided between the second heating part and the fourth heating part.

[0015] Secondly, in this application embodiment, a single crystal furnace is proposed, including the heater described in any of the above claims.

[0016] Optionally, the single crystal furnace further includes a crucible side; when the crucible side is in the lower limit position, the heater is arranged around the crucible side, and the minimum distance between the connector and the crucible side is greater than or equal to 15 mm.

[0017] In this embodiment, the heater includes a first foot plate and a second foot plate disposed opposite to each other, and two heating elements connected in parallel between the first foot plate and the second foot plate. The two heating elements, together with the first foot plate and the second foot plate, form a ring structure. In this embodiment, at least one connecting member is also connected between the two heating elements. When the connecting member is connected to the two heating elements, it can provide support for the two heating elements, improving the overall structural strength and rigidity of the heater. This reduces the risk of deformation or even breakage of the heating elements during use, thereby extending the overall service life of the heater.

[0018] Additional aspects and advantages of this application 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 this application. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of a heater in related technologies; Figure 2 This is a schematic diagram of the heater in the embodiments of this application; Figure 3 This is a top view of the heater in Comparative Example 1 of this application under the action of gravity and thermal stress. Figure 4 This is a side view of the heater in Comparative Example 1 of this application under the action of gravity and thermal stress. Figure 5 This is a top view of the heater in Embodiment 1 of this application deformed under the action of gravity and thermal stress; Figure 6 This is a side view of the heater in Embodiment 1 of this application under the action of gravity and thermal stress; Figure 7 This is a simplified structural diagram of a heater in one embodiment of this application; Figure 8 This is a simplified structural diagram of the heater in another embodiment of this application; Figure 9 This is a current distribution diagram of the heater in Comparative Example 1 of this application; Figure 10 This is a current distribution diagram of the heater in Embodiment 2 of this application; Figure 11 This is a current distribution diagram of the heater in Comparative Example 2 of this application; Figure 12 This is a temperature distribution diagram of the heater in Comparative Example 1 of this application; Figure 13 This is a temperature distribution diagram of the heater in Embodiment 2 of this application; Figure 14 This is a temperature distribution diagram of the heater in Comparative Example 2 of this application; Figure 15 This is a cross-sectional view of the single crystal furnace in the embodiments of this application.

[0020] Reference numerals: 10-first foot plate, 20-second foot plate, 30-heating element, 31-heating body, 301-first heating element, 310-first heating section, 311-second heating section, 312-first connecting section, 302-second heating element, 320-third heating section, 321-fourth heating section, 322-second connecting section, 40-connecting element, 41-first surface, 42-second surface, 1-heater, 2-crust side, 3-crucible. Detailed Implementation

[0021] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0023] In the description of this application, it should 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", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] In a single crystal furnace, the heater, as a key thermal field component, is placed outside the crucible to provide heat for melting silicon. However, after prolonged use, the mechanical strength of the heating element in the heater gradually decreases, leading to deformation or even breakage, thus shortening the overall service life of the heater.

[0026] For example, such as Figure 1 The diagram shows the basic structure of the bottom heater. The heater 1 includes a first foot plate 10 and a second foot plate 20 arranged opposite each other, and a heating element 30 connected in parallel between the first foot plate 10 and the second foot plate 20. One end of the heating element 30 is connected to the first foot plate 10, and the other end is connected to the second foot plate 20. At least a portion between the two ends of the heating element 30 has a serpentine structure. In practical applications, the two feet of the heater 1 are connected to electrodes. As the size of the thermal field increases, the heater 1 becomes longer, and with only the two feet serving as support points, the entire heater 1 is suspended. Due to the lack of a connecting support structure, the mechanical strength and overall rigidity of the heating element 30 are insufficient. After prolonged use, under the coupled effect of the heating element 30's own weight and thermal stress, the heating element 30 is prone to twisting, collapse, deformation, or even breakage.

[0027] Based on this, this application provides a heater 1, which is provided with a connector 40. The connector 40 can connect two heating elements 30 arranged in parallel. In practical applications, this can improve the overall support strength of the heater 1 and reduce the deformation of the heater 1.

[0028] In some alternative implementations, such as Figure 2 As shown, a heater 1 is proposed, comprising: a first foot plate 10 and a second foot plate 20 disposed opposite to each other; two heating elements 30, one end of each heating element 30 being connected to the first foot plate 10 and the other end being connected to the second foot plate 20. The two heating elements 30 are connected in parallel between the first foot plate 10 and the second foot plate 20, and together with the first foot plate 10 and the second foot plate 20, form a ring structure; and at least one connecting member 40 is connected between the two heating elements 30.

[0029] Since at least one connector 40 is connected between the two heating elements 30 in this embodiment, the connector 40 can support the two heating elements 30 when both are connected, thus optimizing the overall integrity of the heater 1, improving the structural strength and rigidity of the entire heater 1, thereby reducing the risk of deformation or even breakage of the heating elements 30 during the use of the heater 1, and extending the overall service life of the heater 1.

[0030] When using the heater 1, bolt holes can be selectively provided on the first foot plate 10 and the second foot plate 20, and the heater is connected and fixed to the electrodes inside the single crystal furnace by bolts. One of the first foot plate 10 and the second foot plate 20 is connected to the positive terminal of the power supply, and the other is connected to the negative terminal. Current flows from one foot plate into one end of each of the two heating elements 30, then travels along the length of the heating element 30 to the other end, and flows out from the other foot plate. The heating element 30 generates heat when current flows through it, providing heat for the melting of the silicon material.

[0031] Optionally, the heating element 30 can be designed as a serpentine structure, that is, the heating element 30 is designed as a slender and reciprocating serpentine heating strip. This extends the current path length compared to a circular heating element, while reducing the effective conductive cross-sectional area and increasing the resistance of the heating element 30. Furthermore, this serpentine structure of the heating element 30 has a larger relative area to the support components (such as crucible sides or crucible supports) used to support the crucible in the single crystal furnace, allowing for more uniform heating of the crucible, improving the thermal convection stability of the silicon melt, and enhancing the crystal growth quality. The heater 1 can be positioned at the bottom of the crucible, with the two heating elements 30 connected to the first electrode foot plate and the second electrode foot plate to form a ring structure, providing clearance for the support components at the bottom of the crucible.

[0032] Optionally, the connector 40 is a strip-shaped rod structure or a plate-shaped structure, including two opposite ends. One end of the connector 40 is connected to one heating element 30, and the other end is connected to another heating element 30. When the connector 40 is connected to two heating elements 30, it can act as a mechanical support, connecting the portions of the two heating elements 30 located between the first foot plate 10 and the second foot plate 20 into a whole. This helps stabilize the relative position of the two heating elements 30, improves the bending and torsional stiffness of the entire heater 1, and allows the structure of the heater 1 to maintain stability better in high-temperature environments.

[0033] Optionally, heater 1 can be made of graphite. Graphite heaters have significant advantages such as structural stability, consistent resistance, and low cost, and can be used for extended periods in an argon-protected gas environment at 2000℃. From a material properties perspective, high-purity graphite has excellent high-temperature resistance, with a sublimation temperature exceeding 3600℃, far higher than the melting point of silicon (1410℃), thus maintaining structural integrity in a high-temperature silicon molten environment. Simultaneously, graphite has moderate and uniform resistivity, generating a stable and uniform thermal field distribution after energization, which is crucial for controlling the temperature gradient at the crystal growth interface and maintaining a stable growth rate. Furthermore, graphite has a low coefficient of thermal expansion and excellent thermal shock resistance, allowing it to withstand frequent heating and cooling cycles without easily cracking or deforming. In terms of process adaptability, the graphite heater can operate long-term in an inert argon-protected atmosphere. The argon environment prevents graphite oxidation at high temperatures and suppresses the volatilization loss of the silicon molten gas, ensuring a pure and controllable crystal growth process. Compared to metal heating elements such as tungsten and molybdenum, graphite heaters are inexpensive and easy to manufacture. They can be produced in various complex structures, such as cylindrical, cup-shaped, and flat, to meet different material loading and thermal field optimization requirements. Graphite itself has a certain degree of plasticity; for large-sized heaters, deformation due to their own weight can accelerate damage. In this embodiment, connecting members are installed between the heating elements to provide support and reduce deformation.

[0034] Alternatively, heater 1 can also be made of carbon-carbon composite material, graphite + silicon carbide composite material, metal material, etc. For heaters made of other materials, the connector of this embodiment can also improve their strength and reduce deformation.

[0035] In some alternative embodiments, the connector 40 and at least one heating element 30 are integrally formed. In some embodiments, the connector 40 is integrally formed with one of the heating elements 30 and spliced ​​with the other heating element 30; in other embodiments, the connector 40 is integrally formed with both heating elements 30.

[0036] In this embodiment, with the connector 40 integrally formed with at least one heating element 30, there are no connection points between the connector 40 and the heating element 30, thereby achieving a more uniform resistance distribution and avoiding adverse effects on the current path. Furthermore, the connection points between separate structures may generate significant internal stress under high-temperature conditions, leading to deformation or cracking. This integrally formed structure eliminates the risk of failure due to thermal stress at the connection points between the connector 40 and the heating element 30, and its overall rigidity and resistance to deformation are superior to those of separate structures.

[0037] In some alternative embodiments, the connector 40 is located between the first foot plate 10 and the second foot plate 20. The foot plate that is closer to the connector 40 is the target foot plate. The minimum distance between the target foot plate and the connector 40 is greater than or equal to 15mm, thereby avoiding the formation of a strong electric field between them and sparking.

[0038] In this embodiment, two heating elements 30 are connected to and enclose the first foot plate 10 and the second foot plate 20 to form a ring structure. A connector 40 connects the two heating elements 30 and is located between the first foot plate 10 and the second foot plate 20. In practical applications, a clearance space needs to be provided at the center of the ring structure to avoid the support components of the single crystal furnace. Therefore, the connector 40 will deviate from the center of the ring structure, resulting in a difference between the distance between the same connector 40 and the first foot plate 10 and the distance between it and the second foot plate 20. One of the first foot plate 10 and the second foot plate 20 will be closer to the connector 40; this foot plate is the target foot plate in this embodiment.

[0039] It should be noted that when both the target foot and the connector 40 are conductive, a potential difference will exist between them. With a constant potential difference, the electric field strength between them is inversely proportional to the minimum distance; that is, the larger the minimum distance, the smaller the electric field strength, and vice versa. When the electric field strength exceeds the gas's tolerance limit, the gas will be ionized and break down, resulting in arcing. This can burn out the heater 1 or even damage the entire single crystal furnace. Furthermore, shutdown for maintenance and component replacement will interrupt crystal growth, affecting production efficiency and potentially causing silicon waste or even scrapping. In this embodiment, by controlling the minimum distance between the target foot and the connector 40 to be greater than or equal to 15mm, arcing can be avoided due to a strong electric field generated by an excessively small distance under the same potential difference, ensuring the safety of the heater 1 and the single crystal furnace.

[0040] Optionally, such as Figure 2 As shown, the surface of the connector 40 adjacent to the target foot plate is the first surface 41, which can be a plane or an arc-shaped surface. If the first surface 41 is an arc-shaped surface, it can be concave towards the connector 40.

[0041] It should be noted that if the first surface 41 of the connector 40 is flat, and the distance between the first surface 41 and the target foot plate meets the requirement of being greater than or equal to 15mm, the first surface 41 of the connector 40 can be designed as flat. When the first surface 41 of the connector 40 is flat, if the minimum distance between the first surface 41 and the target foot plate is less than 15mm, the shape of the connector 40 can be adjusted, and the first surface 41 can be designed as an arc-shaped surface. This arc-shaped surface is concave towards the connector 40, that is, the arc-shaped surface is concave away from the target foot plate, so that the minimum distance between the first surface 41 and the target foot plate can meet the requirement of being greater than or equal to 15mm. Alternatively, the first surface 41 can remain flat, and the shape of the target foot plate can be adjusted so that the distance between it and the flat first surface 41 is greater than or equal to 15mm.

[0042] In some alternative embodiments, the heating element 30 includes a plurality of heating bodies 31 connected sequentially from one end to the other, with at least a portion of the heating bodies 31 connected to form a serpentine structure. Exemplarily, the heating bodies 31 can be plate-shaped or strip-shaped structures, with multiple heating bodies 31 connected end-to-end to form a serpentine structure, which is at least a part of the heating element 30. The connecting member 40 includes a first end and a second end that are opposite to each other; the first end is connected to a heating body 31 in one heating element 30, and the second end is connected to a heating body 31 in another heating element 30.

[0043] In this embodiment, among the plurality of heating elements 31, the minimum cross-sectional area of ​​the heating element 31 connected to the connector 40 is the first cross-sectional area, and the minimum cross-sectional area of ​​the connector 40 is the second cross-sectional area. The second cross-sectional area is greater than or equal to the first cross-sectional area to ensure that the structural strength of the connector 40 is not lower than the structural strength of the heating element 30, thereby improving the support stability of the connector 40 for the heating element 30. The first cross-sectional area is the minimum cross-sectional area of ​​the heating element 31 connected to the connector 40 in a plurality of sections perpendicular to the extension direction of the serpentine structure; the second cross-sectional area is the minimum cross-sectional area of ​​the connector 40 in a plurality of sections perpendicular to its axial direction, where the axial direction of the connector 40 is the direction from the first end to the second end.

[0044] In practical applications, to achieve the same or different heating effects from different heating elements 31, the cross-sectional areas of multiple heating elements 31 can be the same or different, and the cross-sectional area of ​​the connector 40 can also be different at different positions along its length. In this embodiment, the smallest cross-sectional area among the multiple sections of the heating element 31 connected to the connector 40 is defined as the first cross-sectional area, and the smallest cross-sectional area of ​​the connector 40 is defined as the second cross-sectional area. The larger the second cross-sectional area of ​​the connector 40, the higher its structural strength and stiffness. Therefore, by controlling the second cross-sectional area to be greater than or equal to the first cross-sectional area, the structural strength and stiffness of the connector 40 are ensured to be greater than the structural strength and stiffness of the heating element 31 connected to it, preventing the connector 40 from deforming or breaking before the heating element 31 during the operation of the heater 1, thereby continuously providing reliable mechanical support for the heating element 30 throughout the life cycle of the heater 1.

[0045] In some alternative implementations, the number of connectors 40 can be multiple, for example, such as Figure 2 As shown, multiple connectors 40 are respectively connected to two opposite heating elements 30, and are arranged at intervals from the first foot plate to the second foot plate. In this way, the multiple connectors 40 can provide synergistic support for different positions between the two heating elements 30, thereby further improving the overall structural strength and rigidity of the heater 1 and extending the service life of the heater 1.

[0046] In some alternative embodiments, the first heating element 301 includes a first heating portion 310 and a second heating portion 311 arranged symmetrically; the second heating element 302 includes a third heating portion 320 and a fourth heating portion 321 arranged symmetrically.

[0047] For example, such as Figure 2 As shown, the line L1 connecting the center of the first foot plate 10 and the center of the second foot plate 20 is the first axis. The heater 1 also includes a second axis perpendicular to the first axis. Figure 2 In section L2), the first heating element 301 includes a first heating portion 310 and a second heating portion 311 disposed on both sides of the second axis and symmetrically arranged about the second axis. The first heating portion 310 is connected to the first foot plate 10, and the second heating portion 311 is connected to the second foot plate 20. The second heating element 302 includes a third heating portion 320 and a fourth heating portion 321 disposed on both sides of the second axis and symmetrically arranged about the second axis. Among the plurality of connecting members 40, some connecting members 40 are connected between the first heating portion 310 and the third heating portion 320, and other connecting members 40 are connected between the second heating portion 311 and the fourth heating portion 321.

[0048] In this embodiment, the first heating element 310 and the third heating element 320 are close to and connected to the first foot plate 10, and the second heating element 311 and the fourth heating element 321 are close to and connected to the second foot plate 20. By connecting a portion of the multiple connecting members 40 between the first heating element 310 and the third heating element 320, and connecting another portion of the connecting members 40 between the second heating element 311 and the fourth heating element 321, the portions of the first heating element 301 and the second heating element 302 on both sides of the second axis can be effectively supported by the connecting members 40. The stress distribution inside the first heating element 301 and the second heating element 302 on both sides of the second axis is more uniform, reducing the difference in the degree of deformation on both sides of the first heating element 301 and the second heating element 302, thereby reducing the risk of fracture caused by severe deformation on one side of the first heating element 301 and the second heating element 302, and extending the service life of the heater 1.

[0049] In other embodiments, the connecting member 40 may be connected only between the first heating part 310 and the third heating part 320, or only between the second heating part 311 and the fourth heating part 321, which can also provide support for the first heating element 301 and the second heating element 302.

[0050] Furthermore, since heater 1 is generally made of graphite, high-temperature silicon vapor is continuously generated during crystal growth. Under the cyclical corrosive environment of high-temperature silicon vapor, the surface of the graphite heater reacts chemically with the silicon vapor, generating a discontinuous silicon carbide deposit layer. Therefore, in conventional production processes, it is generally necessary to frequently clean the deposits on the surface of heater 1. This continuous corrosion-scraping process causes heater 1 to become increasingly thinner, further degrading its structural load-bearing capacity, forming a vicious cycle of "corrosion-increased strength-more susceptible to damage," severely restricting the service life and operational reliability of heater 1.

[0051] Based on this, in addition to the above embodiments or other alternative embodiments, by controlling the current in the connector 40, the electrical corrosion of the connector 40 can be reduced, thereby ensuring that the connector 40 can provide mechanical support for a long time.

[0052] In some alternative embodiments, the two heating elements 30 are a first heating element 301 and a second heating element 302. The first heating element 301 is provided with a first connecting portion 312, and the second heating element 302 is provided with a second connecting portion 322. One end of the connector 40 is connected to the first connecting portion 312 on the first heating element 301, and the other end is connected to the second connecting portion 312 on the second heating element 302.

[0053] For example, refer to Figure 7The diagram shows a simplified structural diagram of heater 1 in this application example. The left foot is the first foot 10, the right foot is the second foot 20, the heating element 30 above the first foot 10 and the second foot 20 is the first heating element 301, and the heating element 30 below the first foot 10 and the second foot 20 is the second heating element 302. The two ends of the first heating element 301 are represented by a1 and a2, respectively, and the two ends of the second heating element 302 are represented by c1 and c2, respectively (the portion between the first heating element 301 and the second heating element 302 is omitted in the diagram). a1 and c1 are connected to the first foot 10, and a2 and c2 are connected to the second foot 20.

[0054] For example, such as Figure 7 As shown, if a connector 40 is provided on the heater 1, for example, only the left connector 40, the first heating element 301 is provided with a first connecting portion 312, denoted as b1, and the second heating element 302 is provided with a second connecting portion 322, denoted as d1. In the embodiment of the application, for this connector 40, R11 represents the resistance between a1 and b1, R21 represents the resistance between c1 and d1, R12 represents the resistance between b1 and a2, and R22 represents the resistance between d1 and c2.

[0055] Wherein, when the resistance of each region corresponding to the first heating element 301 and the second heating element 302 respectively satisfies: |R11-R21| / R21*100%≤10%, and / or |R12-R22| / R22*100%≤10%, the current flowing into one foot plate will flow into the first heating element 301 and the second heating element 302 relatively evenly, and the potential difference between the two ends of the connector 40 is small, the current flowing into the connector 40 is relatively small or there is no current, thereby reducing the electrochemical corrosion of the connector 40.

[0056] Preferably, resistors R11 and R21 are equal, and resistors R12 and R22 are equal, in which case the current through connector 40 is almost zero.

[0057] In this embodiment, resistors R11 and R21 are equal, and resistors R12 and R22 are also equal. Exemplarily, this application... Figure 7 Taking heater 1 as an example, the resistance between a1 and b1 in the first heating element is the same as the resistance between c1 and d1 in the second heating element, and the resistance between b1 and a2 in the first heating element is the same as the resistance between d1 and c2 in the second heating element. Thus, the resistance between a1 and a2 in the first heating element is the same as the resistance between c1 and c2 in the second heating element.

[0058] In this embodiment, the resistances of different regions of the first heating element 301 and the second heating element 302 satisfy R11=R21 and R12=R22. Therefore, the overall resistances of the first heating element 301 and the second heating element 302 are the same. Thus, the current flowing from the first foot plate 10 or the second foot plate 20 will flow evenly to the first heating element 301 and the second heating element 302 connected in parallel between the first foot plate 10 and the second foot plate 20.

[0059] exist Figure 7 In the heater 1 shown, it is assumed that the current flows from the second foot plate 20 to the first foot plate 10 in the first heating element 301 and the second heating element 302 (from right to left in the figure). Since the resistance of the first heating element 301 and the second heating element 302 is the same, the current will flow evenly from the second foot plate 20 to a2 and c2, and in the first heating element 301 it flows from a2 to b1, and in the second heating element 302 it flows from c2 to d1. At this point, since connector 40 connects b1 and d1, if connector 40 is made of a conductive material (such as graphite), in the first heating element 301, after the current flows from a2 to b1, it can continue to flow along the first heating element 301 to a1, or flow through connector 40 to d1 and then to c1 in the second heating element 302. In the second heating element 302, after the current flows from c2 to d1, it can continue to flow along the second heating element 302 to c1, or flow through connector 40 to b1 and then to a1 in the first heating element 301. The choice of path mainly depends on the resistance of the path; that is, the current will preferentially flow to the path with lower resistance. Considering that the current flowing through connector 40 will cause connector 40 to heat up and the surrounding electric field strength to be high, high-temperature silicon vapor is prone to chemically react with the surface of connector 40 to form a silicon carbide adhesion layer. This adhesion layer is easily peeled off during furnace dismantling and cleaning operations, causing corrosion and thinning of connector 40. Therefore, in this embodiment, by controlling the resistance between a1 and b1 to be the same as the resistance between c1 and d1, and the resistance between b1 and a2 to be the same as the resistance between d1 and c2, the current in the first heating element 301, after flowing to b1, will continue to flow along the original current path. Similarly, the current in the second heating element 302, after flowing to d1, will also continue to flow along the original current path, thereby preventing current from flowing through the connector 40. This can reduce the heating of the connector 40, keep the electric field strength around the connector 40 at a low level, and reduce the risk of corrosion and thinning of the connector 40.

[0060] In some alternative embodiments, a plurality of connecting members are sequentially and spaced apart between the first heating element 301 and the second heating element 302, and the plurality of connecting members are arranged in parallel.

[0061] For example, such as Figure 8As shown, if there are two connectors 40 on the heater 1, the two connectors 40 are spaced apart between the first heating element and the second heating element, and the two connectors are connected in parallel.

[0062] For example, such as Figure 8 As shown, if there are two connectors 40 on the heater 1, then the first heating element 301 is provided with two first connecting parts 312, which are represented by b1 and b2 respectively, and the second heating element 302 is provided with two second connecting parts 322, which are represented by d1 and d2 respectively.

[0063] The resistance of the first heating element 301 between two adjacent connectors 40 is R1, that is, the resistance between b1 and b2 is R1. The resistance of the second heating element 302 between two adjacent connectors 40 is R2, that is, the resistance between d1 and d2 is R2. This satisfies |R1-R2| / R2*100%≤10%. By limiting the ratio of the absolute value of the difference between resistances R1 and R2 to resistance R2 to less than or equal to 10%, the resistance relationship between the first heating element 301 and the second heating element 302 between two adjacent connectors 40 is limited, minimizing the potential difference across the connectors 40, thereby reducing the electric field on the connectors 40 and reducing electrochemical corrosion of the connectors 40.

[0064] Furthermore, referring to Figure 8 As shown, the first heating element 301 is connected to the first foot plate 10 and the connecting member 40 adjacent to the first foot plate 10. Figure 8 The resistance between the connecting piece 40 on the left side of the first foot plate 10 and the connecting piece 40 adjacent to the first foot plate 10 is R11, and the resistance between the second heating element 302 and the connecting piece 40 adjacent to the first foot plate 10 is R21; that is, the resistance between a1 and b1 is R11, and the resistance between C1 and d1 is R21. The first heating element 301 is between the second foot plate 20 and the connecting piece 40 adjacent to the second foot plate 20. Figure 8 The resistance between the connecting parts 40 on the right side of the first heating element 301 and the second heating element 302 is R12, and the resistance between the connecting parts 40 adjacent to the second foot plate 10 and the second foot plate 20 is R22; that is, the resistance between a2 and b2 is R12, and the resistance between c2 and d2 is R22. This satisfies |R11-R21| / R21*100%≤10% and |R12-R22| / R22*100%≤10%. At this time, by limiting the resistance relationship between the corresponding parts of the first heating element 301 and the second heating element 302, the current flowing through the connecting parts 40 is very small or non-existent, thereby reducing the electrochemical corrosion of the connecting parts 40. Preferably, the resistances R1 and R2 are equal, the resistances R11 and R21 are equal, and the resistances R12 and R22 are equal, at which point the current flowing through the connecting parts 40 is almost zero.

[0065] Optionally, the number of connectors 40 provided on the heater 1 is more than two, for example, n+1, where n≥1; in this case, n+1 connectors 40 are sequentially and spaced apart between the first heating element 301 and the second heating element 302, and the n+1 connectors 40 are arranged in parallel.

[0066] The two ends of the first heating element 301 are represented by a1 and a2, respectively, and the two ends of the second heating element 302 are represented by c1 and c2, respectively. On the first heating element 301, starting from the first foot plate 10, the first connecting part immediately adjacent to the first foot plate 10 is b1, and the remaining first connecting parts are b2...bn, bn+1 in sequence. On the second heating element 302, starting from the first foot plate 10, the second connecting part immediately adjacent to the first foot plate 10 is d1, and the remaining second connecting parts are d2...dn, dn+1 in sequence.

[0067] Starting from the first foot plate 10, the two ends of the first connector 40 adjacent to the first foot plate 10 are respectively connected to the first connecting part b1 and the second connecting part d1; the two ends of the second connector 40 are respectively connected to the first connecting part b2 and the second connecting part d2...; the two ends of the nth connector 40 are respectively connected to the first connecting part bn and the second connecting part dn; the two ends of the (n+1)th connector 40 are respectively connected to the first connecting part bn+1 and the second connecting part dn+1.

[0068] Specifically, the resistance between the first connecting part bn+1 and the first connecting part bn on the first heating element 301 is R1, and the resistance between the second connecting part dn+1 and the second connecting part dn on the second heating element is R2; satisfying |R1-R2| / R2*100%≤10%. Taking n=1 as an example, the resistance between the first connecting part b2 and the first connecting part b1 on the first heating element 301 is R1, and the resistance between the second connecting part d2 and the second connecting part d1 on the second heating element 302 is R2, satisfying |R1-R2| / R2*100%≤10%.

[0069] By limiting the resistance difference between the corresponding first heating element 301 and second heating element 302 between adjacent connectors 40 to a controllable range, the potential difference between the two ends of connector 40 is reduced, thereby reducing the electric field on connector 40 and reducing the electrochemical corrosion of connector 40. In practical applications, the high-temperature silicon vapor in a single-crystal furnace carries a positive charge and easily moves directionally under the influence of an electric field. If the electric field strength around the connector 40 is high, the high-temperature silicon vapor easily reacts chemically with the surface of the connector 40 to form a silicon carbide deposit layer. A high electric field easily adsorbs silicon vapor, easily producing easily detachable silicon carbide, causing corrosion and thinning of the connector 40. However, in this embodiment, by designing the resistance on both sides of the first connection portion 312 on the first heating element 301 connected to the connector 40, and the resistance on both sides of the second connection portion 312 on the second heating element 302 connected to the connector 40, it is possible to ensure that no current or only a small amount of current flows through the connector 40. The electric field strength near the connector 40 is weak, or even non-existent, and its ability to attract silicon ions is also relatively low. Therefore, the surface of the connector 40 is not easily reacted with the high-temperature silicon vapor, which can prevent the formation of an easily detachable silicon carbide deposit layer on the surface of the connector 40, thereby maintaining the initial mechanical strength, improving the support effect on the first heating element 301 and the second heating element 302, and thus extending the service life of the heater 1.

[0070] In some alternative implementations, such as Figure 2 As shown, the two heating elements 30 are symmetrically arranged between the first foot plate 10 and the second foot plate 20.

[0071] For example, the line L1 connecting the center of the first foot plate 10 and the center of the second foot plate 20 is the first axis, and the two heating elements 30 are symmetrically arranged about the first axis.

[0072] For example, such as Figure 7 , Figure 8 As shown, the two heating elements 30 can also be arranged asymmetrically about the first axis.

[0073] It should be noted that, according to the law of resistance, R=ρL / S, where ρ is the resistivity of the material, L is the length of the conductor, and S is the cross-sectional area of ​​the conductor. When the two heating elements 30 are made of the same material, the resistivity ρ of the two heating elements 30 is the same, and their resistance is related to their length L and cross-sectional area S.

[0074] When the two heating elements 30 are symmetrically arranged about the first axis, the two heating elements 30 have the same structure, that is, the length and cross-sectional area of ​​the two heating elements 30 are equal, so the resistance requirements of the two heating elements 30 mentioned above can be met.

[0075] In the case where the two heating elements 30 are arranged asymmetrically about the first axis, for example Figure 7As shown in the simplified structural diagram of heater 1, the resistance requirements of the two heating elements 30 can be met by adjusting the length L and cross-sectional area S of the two heating elements 30 according to the above formula. Therefore, in this embodiment, there is no limitation on whether the two heating elements 30 are symmetrically arranged about the first axis, so as to improve the flexibility of the structural design of heater 1.

[0076] In summary, the heater 1 provided in this application embodiment may include at least the following advantages: In this embodiment, the heater 1 includes a first foot plate 10 and a second foot plate 20 disposed opposite to each other, and two heating elements 30 connected in parallel between the first foot plate 10 and the second foot plate 20. The two heating elements 30, together with the first foot plate 10 and the second foot plate 20, form a ring structure. In this embodiment, at least one connecting member 40 is also connected between the two heating elements 30. When the connecting member 40 is connected to both heating elements 30, it can provide support for the two heating elements 30, optimize the overall integrity of the heater 1, improve the structural strength and rigidity of the entire heater 1, thereby reducing the risk of deformation or even breakage of the heating elements 30 during the use of the heater 1 and extending the overall service life of the heater 1.

[0077] like Figure 15 As shown in the embodiment of this application, a single crystal furnace is also provided, including the heater 1 as described above.

[0078] It should be noted that in this embodiment, the structure of heater 1 is the same as that of heater 1 in any of the above embodiments, and its beneficial effects are similar, so it will not be described in detail here.

[0079] Optionally, the single crystal furnace also includes a crucible side 2, which is disposed at the bottom of the crucible 3 to support the crucible 3. The heater 1 is disposed around the crucible side 2, and the minimum distance between the connector 40 and the crucible side 2 is greater than or equal to 15 mm.

[0080] It should be noted that, similar to the aforementioned limitation on the distance between the connector 40 and the target foot plate, in this embodiment of the application, by limiting the minimum distance between the connector 40 and the crucible side 2 to be greater than or equal to 15mm, it is possible to avoid the formation of a strong electric field between the connector 40 and the crucible side 2, which could lead to arcing.

[0081] like Figure 2 As shown, the connector 40 includes a first surface 41 and a second surface 42 disposed opposite to each other. The second surface 42 is close to the center of the heater 1 and is disposed opposite to the crucible side 2. The distance between the second surface 42 and the crucible side 2 is not less than 15mm.

[0082] In practical applications, both the crucible side 2 and the connector 40 are made of conductive graphite. Since both are conductors, a potential difference exists between the connector 40 and the crucible side 2. With a constant potential difference, the electric field strength between them is inversely proportional to the distance between them; that is, the larger the distance, the smaller the electric field strength, and vice versa. When the electric field strength exceeds the tolerance limit of air, the air will be ionized and break down, resulting in arcing. This can burn out the heater 1 or the crucible side 2, or even damage the entire single crystal furnace. Furthermore, furnace shutdown for maintenance and component replacement will interrupt crystal growth, affecting production efficiency and potentially causing silicon waste or even scrapping. In this embodiment, by controlling the distance between the connector 40 and the crucible side 2 to be greater than or equal to 15mm, arcing can be avoided due to a strong electric field generated between the connector 40 and the crucible side 2 at the same potential difference, ensuring the safety of the heater 1, the crucible side 2, and the single crystal furnace.

[0083] Example 1 In this embodiment, a heater 1 is provided as follows: Figure 2 As shown, it includes a first foot plate 10 and a second foot plate 20, with a first heating element 301 and a second heating element 302 connected in parallel between the first foot plate 10 and the second foot plate 20; two connecting members 40 are provided between the first heating element 301 and the second heating element 302. The first heating element 301 and the second heating element 302 have a serpentine structure.

[0084] by Figure 2 The heater 1 shown in this application, with connector 40, is an example of Embodiment 1. Figure 1 The heater 1 shown without connector 40 serves as Comparative Example 1. The only difference between Comparative Example 1 and Example 1 is the presence or absence of connector 40. The heaters 1 in Comparative Example 1 and Example 1 were operated under the same working environment and conditions for a period of time, and their deformation was observed. Figures 3 to 6 The diagram shows the deformation.

[0085] Reference Figure 3 The diagram shows a top view of the heater 1 in Comparative Example 1 of this application under the action of gravity and thermal stress, with reference to... Figure 4 The diagram shows a side view of the heater 1 in Comparative Example 1 of this application under the influence of gravity and thermal stress; refer to Figure 5 A top view showing the deformation of heater 1 in Embodiment 1 of this application under gravity and thermal stress is shown; refer to Figure 6 This shows a side view of the heater 1 in Embodiment 1 of this application deformed under the action of gravity and thermal stress. Figures 3 to 6 The dashed arrows in the diagram schematically indicate the deformation direction of the heating element 30.

[0086] according to Figure 3 and Figure 5The comparison shows that, under the same conditions, in the plane where heater 1 is located, the part of heater 1 without connector 40 has a more severe deformation in the first axis direction than heater 1 with connector 40. In heater 1 with connector 40, since connector 40 connects the two heater 30, it plays a significant supporting role for the two heater 30, reducing the deformation of the heater 30 in the first axis direction, so that heater 1 can still maintain its initial shape well after working for a period of time.

[0087] exist Figure 4 and Figure 6 In the diagram, the horizontal dashed line represents the plane containing the lowest point of the heating element 30 after it collapses along the thickness direction of the heater 1. Initially, the heating element 30, the first foot plate 10, and the second foot plate 20 are located in the same plane. As the working time increases, the heating element 30 begins to collapse and deform downwards. A gap begins to form between the dashed line and the first foot plate 10 or the second foot plate 20, and this gap can represent the degree of collapse of the heating element 30. According to... Figure 4 and Figure 6 The comparison shows that, under the same conditions, in the thickness direction of the heater, the distance between the part of the heating element 30 near the center of the heater 1 and the bottom of the first foot plate 10 or the second foot plate 20 in the thickness direction is larger in the heater 1 without the support of the connector 40, indicating that the heating element 30 in the comparative example collapses more severely. In contrast, in the heater 1 with the support of the connector 40, since the connector 40 connects the two heating elements 30, the distance between the part of the heating element 30 near the center of the heater 1 and the bottom of the first foot plate 10 or the second foot plate 20 in the thickness direction is relatively smaller, indicating that the heating element 30 in the embodiment collapses less severely. That is, the design of the connector 40 reduces the degree of collapse of the part of the heating element 30 near the center of the heater 1.

[0088] Therefore, by connecting the two heating elements 30 with a connector 40, the deformation of the heating element 30 in the plane of the heater 1 and in the thickness direction of the heater 1 can be effectively controlled, making the structure of the heater 1 more stable and helping to extend its service life.

[0089] Example 2 In this embodiment, a heater 1 is provided, the structure of which is as follows: Figure 2 As shown, but the resistance of heater 1 needs further optimization.

[0090] Figure 2 As shown in the structural diagram of Embodiment 2, the number of connecting members 40 provided on the heater 1 is two, correspondingly similar to... Figure 8 The simplified diagram of the heater shown is in Figure 2 In the heater 1 shown, the first heating element 301 has two first connecting portions 312, denoted as b1 and b2 respectively, and the second heating element 302 has two second connecting portions 322, denoted as d1 and d2 respectively. In this embodiment, for the first heating element 301, R11 represents the resistance between a1 and b1, R1 represents the resistance between b1 and b2, and R12 represents the resistance between b2 and b2. For the second heating element 302, R21 represents the resistance between C1 and d1, R2 represents the resistance between d1 and d2, and R22 represents the resistance between d2 and C2.

[0091] In Example 2, the resistances of each part satisfy the following conditions: R11=R21, R1=R2, R12=R22. Specifically, in Example 2, for the first heating element, the corresponding values ​​are R11=10mΩ, R1=30mΩ, and R12=10mΩ; for the second heating element, the corresponding values ​​are R21=10mΩ, R2=30mΩ, and R22=10 mΩ.

[0092] Continue with Figure 2 The heater 1 shown is a comparative example 2, the difference being that the resistance of the heater 1 is different: for example, in comparative example 2, for the first heating element, the corresponding R11=15mΩ, R1=30mΩ, and R12=10 mΩ; for the second heating element, the corresponding R21=10mΩ, R2=30mΩ, and R22=10 mΩ.

[0093] Figure 9 for Figure 1 A schematic diagram of the current in the heater structure, comparing Example 2 and Example 2. Figure 1 Based on heater 1, with the addition of connector 40 and the control of its resistance to meet the above requirements, current is passed through heater 1 in Comparative Example 2 and Example 2, and the internal current distribution is observed. Figure 10 , Figure 11 The diagram shows the internal current distribution. Wherein, Figure 10 A schematic diagram of the current distribution in Example 2 is shown. Figure 11 A schematic diagram of the current distribution in Comparative Example 1 is shown. Figures 9 to 11 The arrow in the diagram indicates the direction of the current within heater 1.

[0094] according to Figure 10 It can be concluded that when a connector 40 is connected between the two heating elements 30, and R11=R21 and R12=R22, the current still flows out from the second foot plate 20 and flows along the first heating element 301 to the first foot plate 10. No current passes through the position of the connector 40. That is, the design of adding a connector 40 to the heater 1 will not change the current flow direction and path of the original heater 1.

[0095] According to Figure 11 It can be concluded that in Comparative Example 2, since the resistances of the two heating elements 30 do not satisfy the conditions R11=R21, R1=R2 and R12=R22, when the current in the first heating element 301 flows from the second foot plate 20 to the left connecting member 40, part of the current flows through the left connecting member 40 to the second heating element 302, and then flows through the second heating element 302 to the first foot plate 10; while the current in the second heating element 302 flows from the second foot plate 20 to the left connecting member 40 and then continues to flow along the second heating element 302 to the first foot plate 10. Ultimately, this results in current flowing through the left connecting member 40, and the current distribution between the first heating element 301 and the second heating element 302 is uneven.

[0096] Furthermore, after the heater 1 in Comparative Example 2 and Example 2 has been operating for a period of time, its temperature distribution is observed, referring to... Figures 12 to 14 Temperature distribution diagrams of heater 1 in Comparative Example 1, Example 2, and Comparative Example 2 are shown respectively. Figures 12 to 14 In the diagram, darker colors indicate lower temperatures, while lighter colors indicate higher temperatures.

[0097] according to Figure 12 It can be concluded that after the heater 1 in Comparative Example 1 has been working for a period of time, the temperature in the area between the first foot plate 10 and the second foot plate 20 remains relatively low, while the temperature of the two heating elements 30 between the first foot plate 10 and the second foot plate 20 is higher and more uniform; according to Figure 13 It can be concluded that after the heater 1 in Example 2 has been working for a period of time, since no current flows through the connector 40, no Joule heat is generated inside the connector 40, thus the temperature can be maintained at a low level, and the risk of corrosion and thinning can be reduced; at the same time, the temperature distribution of the two heating elements 30 is relatively uniform, and the heating effect is more balanced. And according to... Figure 14 The temperature distribution diagram of heater 1 shown in Comparative Example 2 is similar to... Figure 11 The current distribution of heater 1 in Comparative Example 2 is related to the current distribution. Because current flows through the left connector 40, its temperature is higher than that of the right connector 40. Furthermore, the temperature of the second heating element 302 between the left connector 40 and the first foot plate 10 is higher. The uneven current distribution between the two heating elements 30 also affects the overall temperature uniformity of heater 1. Therefore, in the heater of Comparative Example 2, because the resistances do not satisfy R11=R21 and R12=R22, the overall heating uniformity of heater 1 is poor, and current flows through the connector 40, generating heat. This results in a higher risk of corrosion and thinning compared to the heater in Example 2.

[0098] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0099] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A heater (1), characterized in that, The heater (1) includes: The first footplate (10) and the second footplate (20) are set relative to each other; Two heating elements (30) are provided, one end of which is connected to the first foot plate (10) and the other end of which is connected to the second foot plate (20). The two heating elements (30) are connected in parallel between the first foot plate (10) and the second foot plate (20), and are enclosed with the first foot plate (10) and the second foot plate (20) to form a ring structure. and at least one connector (40) connected between the two heating elements (30).

2. The heater (1) according to claim 1, characterized in that, The connector (40) is located between the first foot plate (10) and the second foot plate (20). The foot plate that is closer to the connector (40) between the first foot plate (10) and the second foot plate (20) is the target foot plate. The minimum distance between the target foot plate and the connector (40) is greater than or equal to 15mm.

3. The heater (1) according to claim 2, characterized in that, The surface of the connector (40) adjacent to the target foot plate is a first surface (41), which is either a plane or an arc surface; when the first surface (41) is an arc surface, the arc surface is concave to the connector (40).

4. The heater (1) according to claim 1, characterized in that, From one end of the heating element (30) to the other end, the heating element (30) includes a plurality of heating bodies (31) connected in sequence, and at least some of the heating bodies (31) are connected to form a serpentine structure; the minimum cross-sectional area of ​​the heating body (31) is a first cross-sectional area, and the minimum cross-sectional area of ​​the connecting member (40) is a second cross-sectional area, and the second cross-sectional area is greater than or equal to the first cross-sectional area.

5. The heater (1) according to claim 1, characterized in that, The connector (40) and at least one of the heating elements (30) are integrally formed.

6. The heater (1) according to any one of claims 1 to 5, characterized in that, The two heating elements (30) are a first heating element (301) and a second heating element (302), respectively. A plurality of connecting members (40) are arranged sequentially and spaced apart between the first heating element (301) and the second heating element (302), and the plurality of connecting members (40) are arranged in parallel.

7. The heater (1) according to claim 6, characterized in that, The resistance of the first heating element (301) between two adjacent connecting elements (40) is R1, and the resistance of the second heating element (302) between two adjacent connecting elements (40) is R2. Among them, |R1-R2| / R2*100%≤10% is satisfied.

8. The heater (1) according to claim 1 or 7, characterized in that, The two heating elements (30) are a first heating element (301) and a second heating element (302), respectively. The resistance of the first heating element (301) between the first foot plate (10) and the connecting member (40) adjacent to the first foot plate (10) is R11, and the resistance of the second heating element (302) between the first foot plate (10) and the connecting member (40) adjacent to the first foot plate (10) is R21; wherein, |R11-R21| / R21*100%≤10%; and / or, The resistance of the first heating element (301) between the second foot plate (20) and the connecting member (40) adjacent to the second foot plate (20) is R12, and the resistance of the second heating element (302) between the second foot plate (20) and the connecting member (40) adjacent to the second foot plate (20) is R22; wherein, |R12-R22| / R22*100%≤10% is satisfied.

9. The heater (1) according to claim 8, characterized in that, R1=R2, R12=R22, R11=R21.

10. The heater (1) according to any one of claims 1 to 5, characterized in that, The two heating elements (30) are symmetrically arranged between the first foot plate (10) and the second foot plate (20).

11. The heater (1) according to any one of claims 1 to 5, characterized in that, The two heating elements (30) are a first heating element (301) and a second heating element (302); the first heating element (301) includes a first heating part (310) and a second heating part (311) arranged symmetrically on the axis; the second heating element (302) includes a third heating part (320) and a fourth heating part (321) arranged symmetrically on the axis. One end of the first heating part (310) and one end of the third heating part (320) are connected to the first foot plate (10); one end of the second heating part (311) and one end of the fourth heating part (321) are connected to the second foot plate (20); The connecting member (40) is connected between the first heating part (310) and the third heating part (320); and / or, the connecting member (40) is connected between the second heating part (311) and the fourth heating part (321).

12. A single crystal furnace, characterized in that, Includes the heater (1) as described in any one of claims 1 to 11.

13. The single crystal furnace according to claim 12, characterized in that, The single crystal furnace also includes a crucible side (2); when the crucible side (2) is in the lower limit position, the heater (1) is arranged around the crucible side (2), and the minimum distance between the connector (40) and the crucible side (2) is greater than or equal to 15mm.

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