A heating device and a single crystal furnace

Abstract

The present invention discloses a heating device and a single crystal furnace. The heating device includes a main heater and an auxiliary heater. Among them, the main heater is arranged on the periphery of the crucible and is configured to heat the crucible. The auxiliary heater is arranged on the periphery of the crucible and below the main heater. There is a gap △x between the auxiliary heater and the main heater in the height direction. The auxiliary heater is at least configured to heat the crucible during the silicon material melting stage and the crystal bar equal diameter growth stage, where 20mm ≤ △x ≤ 60mm. The above heating device improves the heating efficiency by adding an auxiliary heater below the main heater, thereby improving the melting efficiency. At the same time, the cooperation of the main heater and the auxiliary heater can ensure the uniformity of the temperature field in the furnace body, which is beneficial to improving the overall quality of the crystal.

Description

Technical Field

[0001] The present invention belongs to the technical field of single crystal furnaces, and particularly relates to a heating device and a single crystal furnace. Background Art

[0002] With the continuous improvement of the quality requirements for semiconductor silicon wafers, higher requirements are imposed on the quality of the crystal rod during the crystal pulling process. The structure and performance of the thermal field directly affect the quality of the crystal rod. Therefore, the design of the thermal field is crucial. For a single crystal furnace, the design of the heater is one of the cores of the thermal field design. The heater undertakes the heat output of the single crystal furnace and plays an important role in both the melting stage of polysilicon material and the later forming stage. Its shape and the size of the heating area directly affect the temperature field of the crystal pulling furnace, and thus affect the quality of the crystal rod.

[0003] The heating devices for single crystal furnaces in the prior art generally include a main heater located outside the crucible and a bottom heater located at the bottom of the thermal field. Such heating devices generally have the disadvantages of low heating efficiency and uneven temperature field in the specific use process. Especially in the later stage of the equal diameter growth of the crystal rod, as the melt continuously decreases, the ability of the melt to retain heat decreases, which further exacerbates the unevenness of the melt temperature field to a greater extent, resulting in significant temperature oscillation at the solid-liquid interface. Summary of the Invention

[0004] The purpose of the present invention is to provide a heating device to solve the problems of low heating efficiency and uneven temperature field existing in the heating device in the prior art. In addition, the present invention also provides a single crystal furnace including the above heating device.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] A heating device includes a main heater and an auxiliary heater. Among them, the main heater is arranged outside the crucible and is configured to heat the crucible. The auxiliary heater is arranged outside the crucible and below the main heater. There is a gap △x between the auxiliary heater and the main heater in the height direction. The auxiliary heater is at least configured to heat the crucible during the melting stage of silicon material and the equal diameter growth stage of the crystal rod, where 20mm ≤ △x ≤ 60mm.

[0007] By adding an auxiliary heater below the main heater, the heating efficiency is improved, and thus the melting efficiency of the melt is enhanced. A gap is maintained between the auxiliary heater and the main heater, which can reduce the temperature gradient difference of the melt in the crucible, thereby reducing the temperature oscillation at the solid-liquid interface during the crystal pulling process and improving the quality of the pulled crystal rod. Additionally, a gap is maintained between the auxiliary heater and the main heater, which suppresses the natural convection of the melt and can effectively control the oxygen precipitation at the melt surface, thereby reducing the oxygen content in the crystal rod. Controlling the gap △x between the auxiliary heater and the main heater within 20 mm to 60 mm helps to effectively improve the quality of the crystal rod. On the one hand, it can avoid excessive current caused by too small a gap, resulting in arcing between the auxiliary heater and the main heater and affecting the normal operation of the heating device. On the other hand, it can avoid the auxiliary heater being too close to the bottom of the crucible due to too large a gap, which affects the oxygen reduction effect.

[0008] Optionally, the auxiliary heater includes at least two heating monomers, and the at least two heating monomers enclose a cylindrical heating body. The main heater is cylindrical as a whole, and the inner diameter and outer diameter of the auxiliary heater are the same as the inner diameter and outer diameter of the main heater respectively.

[0009] By setting the auxiliary heater as a split structure, it is convenient for the manufacture, disassembly and assembly of the auxiliary heater. At the same time, setting the main heater and the auxiliary heater as cylindrical structures with the same inner and outer diameters can ensure that the size of the crucible does not become smaller, and the temperature gradient in the axial direction towards the position of the crystal rod during heating is more uniform, making the temperature gradient of the thermal field more stable and facilitating crystal pulling.

[0010] Optionally, the value range of the heating zone height h1 of the main heater and the heating zone height h2 of the auxiliary heater is: 100 mm ≤ h1 ≤ 250 mm, 50 mm ≤ h2 ≤ 150 mm.

[0011] Based on the existing main heater, by reducing the heating zone height of the main heater and setting the heating zone height h1 of the main heater between 100 mm and 250 mm, the heated area of the crucible can be further reduced, and the dissolution between the crucible wall and the silicon solution (SiO2 → Si + 2O) can be weakened, thereby reducing the generation of oxygen and further improving the oxygen reduction effect of the heating device. Setting the heating zone height h2 of the auxiliary heater between 50 mm and 150 mm, on the one hand, when the bottom heater melts and heats the silicon material in the crucible, it can assist in heating the crucible and improve the melting efficiency. In the initial stage of equal diameter, the heating of the auxiliary heater can ensure that the silicon liquid can absorb the required heat and keep the melt in a liquid state. On the other hand, setting the heating zone height h2 of the auxiliary heater between 50 mm and 150 mm can reduce the interference to the main heater, and thus ensure that the silicon liquid in the upper part of the crucible is in a relatively stable state.

[0012] Optionally, the inner diameter of the main heater is not less than 1020 mm, and the outer diameter of the main heater is not greater than 1100 mm.

[0013] The inner diameter of the main heater not being less than 1020 mm ensures that the thermal field can match a 36-inch quartz crucible. The outer diameter not being greater than 1100 mm ensures that the modification of the heater will not affect the use of the outer thermal insulation cylinder. Moreover, this size can ensure the uniformity of the overall temperature field in the entire thermal field system, thereby extending the service life of other thermal field components.

[0014] Optionally, the auxiliary heater is disposed below the main heater in a liftable manner to adjust the gap △x between the auxiliary heater and the main heater.

[0015] Changing the gap △x between the auxiliary heater and the main heater can change the argon gas flow direction and velocity, making the argon gas velocity controllable in a certain area to a certain extent, thereby reducing the velocity to achieve oxygen control. At the same time, it moves the range of the radiation area to reduce the thermal effect on the intersection of the side wall and the bottom wall of the crucible, thereby reducing the oxygen concentration.

[0016] Optionally, the heating device further includes a bottom heater disposed below the crucible. The bottom heater is configured to heat the bottom of the crucible, and the main heater, the auxiliary heater, and the bottom heater are respectively controlled independently for heating.

[0017] By providing the bottom heater, heating of the bottom of the crucible is achieved to melt the silicon material in the crucible. The main heater, the auxiliary heater, and the bottom heater are respectively controlled independently for heating, improving the versatility of the heating device and enabling the heaters to be used alone or in combination under different processes, different equal-diameter lengths, and different process conditions.

[0018] Optionally, the heating device further includes a first power source, a second power source, and a third power source. The first power source is configured to energize and heat the bottom heater, the second power source is configured to energize and heat the main heater, and the third power source is configured to energize and heat the auxiliary heater.

[0019] By providing the first power source, the second power source, and the third power source, independent control of heating for the main heater, the auxiliary heater, and the bottom heater is achieved. At the same time, the main heater, the auxiliary heater, and the bottom heater all adopt electric heating, which has high heating efficiency and is easy to implement.

[0020] A single crystal furnace includes a furnace body, a crucible, and the above-mentioned heating device. The crucible is disposed inside the furnace body, and the heating device is disposed around the crucible.

[0021] By applying the above-mentioned heating device to the single crystal furnace, a single crystal furnace with high heating efficiency and uniform temperature field is provided.

[0022] Optionally, the single crystal furnace further includes a furnace bottom plate, which is arranged in the furnace body and located below the crucible. A plurality of first electrode foot mounting holes and a plurality of second electrode foot mounting holes are formed in the furnace bottom plate. The electrode feet of the main heater are mounted in the plurality of first electrode foot mounting holes, and the electrode feet of the auxiliary heater are mounted in the plurality of second electrode foot mounting holes.

[0023] By forming a plurality of first electrode foot mounting holes and a plurality of second electrode foot mounting holes in the furnace bottom plate, the mounting of the electrode feet of the main heater and the auxiliary heater is realized, providing a simple and convenient mounting method for the electrode feet.

[0024] Optionally, the plurality of first electrode foot mounting holes and the plurality of second electrode foot mounting holes are arranged on the same pitch circle of the furnace bottom plate.

[0025] By arranging all the first electrode foot mounting holes and all the second electrode foot mounting holes on the same pitch circle of the furnace bottom plate, the processing difficulty of the electrode foot mounting holes is reduced on the premise of not affecting the temperature field gradient. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of the heating device provided by the embodiment of the present invention;

[0027] Figure 2 is a schematic installation diagram of the main heater and the auxiliary heater of the heating device provided by the embodiment of the present invention;

[0028] Figure 3 is a top view schematic diagram of the auxiliary heater of the heating device provided by the embodiment of the present invention;

[0029] Figure 4 is a top view schematic diagram of the furnace bottom plate of the single crystal furnace provided by the embodiment of the present invention;

[0030] Figures 1 to 4 The following reference numerals are included:

[0031] Main heater 10,

[0032] Auxiliary heater 20, heating monomer 200,

[0033] Bottom heater 30,

[0034] Furnace body 40,

[0035] Furnace bottom plate 50, first electrode foot mounting hole 500, second electrode foot mounting hole 501, third electrode foot mounting hole 502,

[0036] Electrode foot 60. Detailed Embodiment

[0037] To make the above objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] With the continuous improvement of the quality requirements for semiconductor silicon wafers, higher requirements are placed on the quality of the crystal rods during the crystal pulling process. The structure and performance of the thermal field directly affect the quality of the crystal rods. Therefore, the design of the thermal field is crucial. For a single crystal furnace, the design of the heater is one of the cores of the thermal field design. The heater undertakes the heat output of the single crystal furnace and plays an important role in both the melting stage of polysilicon materials and the later forming stage. Its shape and the size of the heating area directly affect the temperature field of the crystal pulling furnace, and thus affect the quality of the crystal rods.

[0039] In the specific use process of the heating devices in the prior art, there are generally disadvantages such as low heating efficiency and uneven temperature field. Especially in the later stage of the equal-diameter growth of the crystal rod, as the melt continuously decreases, the ability of the melt to retain heat decreases, which further exacerbates the unevenness of the melt temperature field. At the same time, due to the limitation of the heat transfer mode of the traditional heater, the convection mode is not conducive to the effective precipitation of oxygen and the radial uniform immersion of oxygen in the crystal rod, which greatly limits the uniform distribution of oxygen in the crystal rod and affects the overall quality of the crystal rod.

[0040] Therefore, the present invention provides a heating device for heating the crucible of a single crystal furnace. Please refer to Figure 1 and Figure 2 As shown, the heating device provided by the embodiment of the present invention includes a main heater 10 and an auxiliary heater 20. Among them, the main heater 10 is arranged on the periphery of the crucible (not shown in the figure), and the main heater 10 is configured to heat the crucible. The auxiliary heater 20 is arranged on the periphery of the crucible and below the main heater 10. There is a gap △x between the auxiliary heater 20 and the main heater 10 in the height direction. The auxiliary heater 20 is at least configured to heat the crucible during the silicon material melting stage and the equal-diameter growth stage of the crystal rod, where 20mm ≤ △x ≤ 60mm.

[0041] By adding an auxiliary heater 20 below the main heater 10, the heating efficiency is improved, and thus the melting efficiency of the material is enhanced. A gap is maintained between the auxiliary heater 20 and the main heater 10, which can reduce the temperature gradient difference of the melt in the crucible, thereby reducing the temperature oscillation at the solid-liquid interface during the crystal pulling process, ensuring the uniformity of the temperature field in the crucible, and improving the quality of the pulled crystal rod. In addition, a gap is maintained between the auxiliary heater 20 and the main heater 10, which suppresses the natural convection of the melt, can effectively control the precipitation of oxygen at the melt surface, and further reduces the oxygen content in the crystal rod. Controlling the gap △x between the auxiliary heater 20 and the main heater 10 within 20 mm to 60 mm helps to effectively improve the quality of the crystal rod. On the one hand, it can avoid excessive current caused by too small a gap, resulting in arcing between the auxiliary heater 20 and the main heater 10 and affecting the normal operation of the heating device; on the other hand, it can avoid the auxiliary heater 20 being too close to the bottom of the crucible due to too large a gap, increasing the bottom oxygen content and thus affecting the oxygen reduction effect.

[0042] Preferably, the value of △x is: 20 mm, 30 mm, 40 mm, 50 mm or 60 mm.

[0043] Please refer to Figure 3 As shown, as an implementation manner, the auxiliary heater 20 includes at least two heating monomers 200, and the at least two heating monomers 200 enclose a cylindrical heating body. The main heater 10 is in a cylindrical shape as a whole, and the inner diameter and outer diameter of the auxiliary heater 20 are the same as the inner diameter and outer diameter of the main heater 10 respectively.

[0044] Preferably, the auxiliary heater 20 includes two heating monomers 200, and both of the two heating monomers 200 are arc-shaped structures with equal radii, and the two heating monomers 200 enclose a cylindrical heating body.

[0045] By setting the auxiliary heater 20 as a split structure, it is convenient for the manufacture, disassembly and assembly of the auxiliary heater 20. At the same time, by setting the main heater 10 and the auxiliary heater 20 as cylindrical structures with the same inner and outer diameters, it can ensure that the size of the crucible does not become smaller, and the temperature gradient in the axial direction towards the crystal rod position during heating is more uniform, making the temperature gradient of the thermal field more stable and facilitating crystal pulling.

[0046] Please refer to Figure 2 As shown, as an implementation manner, the value range of the heating zone height h1 of the main heater 10 and the heating zone height h2 of the auxiliary heater 20 is: 100 mm ≤ h1 ≤ 250 mm, 50 mm ≤ h2 ≤ 150 mm.

[0047] Setting the height h1 of the heating zone of the main heater 10 between 100 mm and 250 mm can further reduce the heated area of the crucible, weaken the dissolution between the crucible wall and the silicon solution (SiO2 → Si + 2O), thereby reducing the generation of oxygen and further improving the oxygen reduction effect of the heating device.

[0048] Setting the height h2 of the heating zone of the auxiliary heater 20 between 50 mm and 150 mm. On the one hand, when the bottom heater melts and heats the silicon material in the crucible, it can assist in heating the crucible to improve the melting efficiency. In the initial stage of equal diameter, the heating of the auxiliary heater 20 can ensure that the silicon solution can absorb the required heat and keep the melt in a liquid state. On the other hand, setting the height h2 of the heating zone of the auxiliary heater between 50 mm and 150 mm can reduce the interference with the main heater, and then ensure that the silicon solution in the upper part of the crucible is in a relatively stable state.

[0049] Setting the height h1 of the heating zone of the main heater 10 between 100 mm and 250 mm and the height h2 of the heating zone of the auxiliary heater 20 between 50 mm and 150 mm. The cooperation of h1 and h2 can not only improve the oxygen reduction effect but also perform auxiliary heating without interfering with the operation of the main heater.

[0050] Preferably, 100 mm ≤ h1 ≤ 200 mm can further weaken the dissolution between the crucible wall and the silicon solution, which is more conducive to improving the oxygen reduction effect of the heating device. Specifically, the values of h1 are: 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 190 mm or 200 mm. Specifically, the values of h2 are: 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm or 150 mm.

[0051] As an implementation manner, the inner diameter of the main heater 10 is not less than 1020 mm, and the outer diameter of the main heater 10 is not greater than 1100 mm.

[0052] Designing the inner diameter of the main heater 10 to be not less than 1020 mm ensures that the thermal field can match a 36-inch quartz crucible. Designing the outer diameter to be not greater than 1100 mm ensures that the modification of the heater will not affect the use of the outer insulation cylinder, and this size can ensure the uniformity of the overall temperature field in the entire thermal field system, thereby extending the service life of other thermal field components.

[0053] As an implementation manner, the auxiliary heater 20 is disposed below the main heater 10 in a liftable manner to adjust the gap △x between the auxiliary heater 20 and the main heater 10. It should be noted that: the lifting stroke of the auxiliary heater 20 needs to meet the value range of △x.

[0054] In the specific production process of the single crystal furnace, the oxygen concentration is directly proportional to the argon gas flow rate during the growth of the Czochralski silicon single crystal. The argon gas blows downward from above the heater. The change in the gap △x between the auxiliary heater 20 and the main heater 10 can change the argon gas flow direction and flow rate, making the argon gas flow rate controllable in a certain area to a certain extent, so as to reduce the flow rate to control oxygen; at the same time, the structure of the crucible causes the highest temperature of the crucible to appear at the intersection of the side wall and the bottom wall. The change in the gap △x between the auxiliary heater 20 and the main heater 10 makes the range of the radiation area move, so as to reduce the thermal effect on the intersection of the side wall and the bottom wall of the crucible, thereby reducing the oxygen concentration.

[0055] Specifically, the auxiliary heater 20 can be lifted relative to the main heater 10, and the following solutions can be adopted to achieve this:

[0056] Solution 1: The electrode pins of the auxiliary heater 20 are set to be two or more sections that can be vertically telescopic. For example, the first section of the electrode pin is fixedly installed on the furnace chassis, one end of the second section of the electrode pin is telescopically sleeved inside the first section of the electrode pin, and the other end of the second section of the electrode pin is connected to the heating area of the auxiliary heater 20. When installing the auxiliary heater, the second section of the electrode pin can be adjusted to be installed at different height positions relative to the first section of the electrode pin through a pin, that is, the lifting of the auxiliary heater 20 relative to the main heater 10 is realized.

[0057] Solution 2: The electrode pins of the auxiliary heater 20 are separately arranged on a chassis, and the chassis is fixedly arranged on a nut. A motor is used to drive the nut to lift along the lead screw to realize the lifting of the auxiliary heater 20 relative to the main heater 10.

[0058] Please refer to again Figure 1 As shown, as an implementation manner, the heating device further includes a bottom heater 30. The bottom heater 30 is arranged below the crucible and is configured to heat the bottom of the crucible. The main heater 10, the auxiliary heater 20, and the bottom heater 30 are respectively controlled for heating independently.

[0059] By setting the bottom heater 30, heating the bottom of the crucible is realized to melt the silicon material in the crucible; the main heater 10, the auxiliary heater 20, and the bottom heater 30 are respectively controlled for heating independently, providing the versatility of the heating device, and can meet the independent or combined use of each heater under different processes, different equal-diameter lengths, and different process conditions.

[0060] As an implementation manner, the heating device further includes a first power supply, a second power supply, and a third power supply. The first power supply is configured to supply power to heat the bottom heater 30, the second power supply is configured to supply power to heat the main heater 10, and the third power supply is configured to supply power to heat the auxiliary heater 20.

[0061] By setting the first power supply, the second power supply and the third power supply, separate independent control of the heating of the main heater 10, the auxiliary heater 20 and the bottom heater 30 is achieved. At the same time, the main heater 10, the auxiliary heater 20 and the bottom heater 30 all adopt the electric heating method, which has high heating efficiency and is easy to implement.

[0062] The heating device provided by the present invention has the following advantages:

[0063] 1) An auxiliary heater is additionally provided below the main heater, which not only improves the melting efficiency of the silicon material, but also can cooperate with the main heater to ensure the uniformity of the temperature field in the furnace body;

[0064] 2) The gap △x between the auxiliary heater and the main heater can be adjusted, which can not only achieve the oxygen control function to improve the uniformity of the oxygen distribution in the ingot, thereby improving the overall quality of the ingot; but also can reduce the thermal effect on the intersection of the side wall and the bottom wall of the crucible, thereby reducing the oxygen concentration;

[0065] 3) The auxiliary heater adopts a split structure, which is convenient for manufacturing, disassembly and assembly on the premise of ensuring the auxiliary heating function;

[0066] 4) The main heater, the auxiliary heater and the bottom heater are separately and independently controlled for heating, which can meet the use under different processes, different equal-diameter lengths and different process conditions, and has good versatility.

[0067] Please refer to Figure 1 and Figure 4 As shown, the present invention also provides a single crystal furnace, which includes a furnace body 40, a crucible and the above-mentioned heating device. The crucible is arranged in the furnace body 40, and the heating device is arranged on the periphery of the crucible.

[0068] By applying the above-mentioned heating device to the single crystal furnace, a single crystal furnace with high heating efficiency and uniform temperature field is provided.

[0069] As an implementation manner, the single crystal furnace further includes a furnace bottom plate 50. The furnace bottom plate 50 is arranged in the furnace body 40 and is located below the crucible. A plurality of first electrode foot mounting holes 500 and a plurality of second electrode foot mounting holes 501 are opened on the furnace bottom plate 50. The electrode feet 60 of the main heater 10 are mounted in the plurality of first electrode foot mounting holes 500, and the electrode feet 60 of the auxiliary heater 20 are mounted in the plurality of second electrode foot mounting holes 501.

[0070] Specifically, the electrode feet 60 of the two heating monomers 200 of the auxiliary heater 20 are symmetrically arranged on both sides of the electrode feet 60 of the main heater 10, and the distance between adjacent electrode feet 60 is controlled within 20 mm - 40 mm.

[0071] As an implementation manner, a plurality of third electrode pin mounting holes 502 are further formed in the furnace chassis 50, and the electrode pins 60 of the bottom heater 30 are mounted in the plurality of third electrode pin mounting holes 502.

[0072] By forming a plurality of first electrode pin mounting holes 500, a plurality of second electrode pin mounting holes 501 and a plurality of third electrode pin mounting holes 502 in the furnace chassis 50, the mounting of the electrode pins 60 of the main heater 10, the electrode pins 60 of the auxiliary heater 20 and the electrode pins 60 of the bottom heater 30 is realized, providing a simple-structured and easy-to-install electrode pin mounting manner.

[0073] As an implementation manner, the plurality of first electrode pin mounting holes 500, the plurality of second electrode pin mounting holes 501 and the plurality of third electrode pin mounting holes 502 are arranged on the same pitch circle of the furnace chassis 50.

[0074] By arranging all the electrode pin mounting holes on the same pitch circle of the furnace chassis 50, the processing difficulty of the electrode pin mounting holes is reduced on the premise of not affecting the temperature field gradient.

[0075] The above embodiments only illustrate the basic principles and characteristics of the present invention. The present invention is not limited by the above examples. Without departing from the spirit and scope of the present invention, there are various changes and modifications to the present invention, and these changes and modifications all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A heating device, characterized in that, the heating device includes a main heater and an auxiliary heater, wherein, the main heater is arranged on the periphery of the crucible, and the main heater is configured to heat the crucible, the auxiliary heater is arranged on the periphery of the crucible and below the main heater, and there is a gap △x between the auxiliary heater and the main heater in the height direction. The auxiliary heater is at least configured to heat the crucible during the silicon material melting stage and the equal-diameter growth stage of the crystal rod, wherein 20mm ≤ △x ≤ 60mm; the height h1 of the heating area of the main heater and the height h2 of the heating area of the auxiliary heater have a value range of: 100mm ≤ h1 ≤ 250mm, 50mm ≤ h2 ≤ 150mm; the auxiliary heater is arranged below the main heater in a liftable manner to adjust the gap △x between the auxiliary heater and the main heater.

2. The heating device according to claim 1, characterized in that, the auxiliary heater includes at least two heating monomers, and the at least two heating monomers enclose a cylindrical heating body. The main heater is in a cylindrical shape as a whole, and the inner diameter and outer diameter of the auxiliary heater are the same as the inner diameter and outer diameter of the main heater respectively.

3. The heating device according to claim 2, characterized in that, the inner diameter of the main heater is not less than 1020mm, and the outer diameter of the main heater is not greater than 1100mm.

4. The heating device according to claim 1, characterized in that, the heating device further includes a bottom heater, the bottom heater is arranged below the crucible, and the bottom heater is configured to heat the bottom of the crucible. The main heater, the auxiliary heater and the bottom heater are separately controlled for heating.

5. The heating device according to claim 4, characterized in that, the heating device further includes a first power supply, a second power supply and a third power supply. The first power supply is configured to supply power to the bottom heater for heating, the second power supply is configured to supply power to the main heater for heating, and the third power supply is configured to supply power to the auxiliary heater for heating.

6. A single crystal furnace, characterized in that, the single crystal furnace includes a furnace body, a crucible and the heating device according to any one of claims 1-5. The crucible is arranged in the furnace body, and the heating device is arranged on the periphery of the crucible.

7. The single crystal furnace according to claim 6, characterized in that, the single crystal furnace further includes a furnace chassis, the furnace chassis is arranged in the furnace body and below the crucible. A plurality of first electrode pin mounting holes and a plurality of second electrode pin mounting holes are formed in the furnace chassis. The electrode pins of the main heater are mounted in the plurality of first electrode pin mounting holes, and the electrode pins of the auxiliary heater are mounted in the plurality of second electrode pin mounting holes.

8. The single crystal furnace according to claim 7, characterized in that, the plurality of first electrode pin mounting holes and the plurality of second electrode pin mounting holes are arranged on the same pitch circle of the furnace chassis.

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