Oxygen reduction device of single crystal furnace thermal field and single crystal furnace

Abstract

The utility model relates to an oxygen reduction device of a single crystal furnace thermal field and a single crystal furnace, and the oxygen reduction device comprises a main heater which is distributed on the periphery of the upper part of a quartz crucible and is used for heating the quartz crucible; the side heaters are distributed on the periphery of the lower part of the quartz crucible and are positioned below the main heater; the side heater is at least configured to heat the quartz crucible in a silicon material melting stage and is closed in an equal-diameter stage; and the water cooling device is connected with the side heater and is configured to be started at the equal-diameter stage so as to dissipate heat of the side heater. According to the invention, the side heater is closed at the equal-diameter stage, and the water cooling device is additionally arranged, so that oxygen reduction is carried out in a manner of reducing heat convection at the lower part of the quartz crucible, thereby effectively improving the product quality and improving the productivity of the single crystal furnace.

Description

Technical Field

[0001] The present application relates to the technical field of single crystal silicon pulling, and in particular to a single crystal furnace thermal field oxygen reduction device and a single crystal furnace. Background Art

[0002] At present, in the field of solar cell technology, single crystal silicon rods are usually used to make silicon wafers. In related technologies, oxygen impurities in single crystal silicon rods can cause defects such as concentric circles and black heart slices, which seriously affect the efficiency and yield of photovoltaic cells. Low-oxygen silicon single crystals have become a necessity for future high-efficiency batteries. However, with the development of the industry, large-size silicon single crystals have become the mainstream. At the same time, the demand for N-type silicon wafers is increasing, and the low-oxygen requirements of N-type single crystal silicon wafers are relatively high. Therefore, the demand for the production of single crystal silicon with low oxygen content is also increasing. The high oxygen content restricts the development of the entire industry.

[0003] The existing oxygen reduction schemes mainly reduce the height of the heating coil of the heater or reduce the rotation speed of the crucible to reduce the scouring of the quartz crucible or set a heat insulation ring around the crucible to block heat radiation under the side heater or reduce the furnace pressure of the single crystal furnace, increase the argon flow rate or add a superconducting magnetic field to suppress the thermal convection of the silicon liquid through the magnetic field. However, the above-mentioned various oxygen reduction schemes have their own corresponding many disadvantages, which seriously affect the production capacity of the single crystal furnace.

[0004] Therefore, there is an urgent need to provide a single crystal furnace thermal field oxygen reduction device and a single crystal furnace to solve the above-mentioned technical problems. Utility Model Content

[0005] Based on this, a single crystal furnace thermal field oxygen reduction device and a single crystal furnace are provided, which can effectively improve product quality and increase the production capacity of the single crystal furnace.

[0006] On the one hand, a deoxygenation device for a thermal field of a single crystal furnace is provided, comprising: a main heater, which is distributed on the upper periphery of a quartz crucible and is used to heat the quartz crucible; a side heater, which is distributed on the lower periphery of the quartz crucible and is located below the main heater; the side heater is at least configured to heat the quartz crucible in the silicon material melting stage and to be turned off in the equal-diameter stage; a water cooling device, which is connected to the side heater and is configured to be started in the equal-diameter stage to dissipate heat from the side heater.

[0007] A preferred solution is that the side heater and the main heater have a spacing △x in the height direction; the value range of the spacing △x is set to 20-30mm.

[0008] A preferred solution is that the side heater and the main heater are both configured to be cylindrical; the inner diameter of the side heater is at least 15 mm smaller than the inner diameter of the main heater.

[0009] A preferred solution is that the side heater includes at least two heating units, and at least two of the heating units are assembled to form a cylindrical heating body; and the main heater is cylindrical as a whole.

[0010] A preferred solution is that the heating unit is divided into an upper heating zone and a lower heating zone; the upper heating zone includes multiple heating elements and multiple slit areas, each of the slit areas is connected to two adjacent heating elements, and the openings of the multiple slit areas have the same opening direction; the lower heating zone is an integrated seamless structure.

[0011] A preferred solution is that the opening depth of the slit area is the same as the height of at least one of the heating elements in the upper heating zone.

[0012] A preferred solution is that the height of the lower heating zone is the same as the crucible R arc height of the quartz crucible.

[0013] A preferred solution is that the height of the heating unit is set to h1, and the value range of the height h1 is set to 400mm≤h1≤450mm; the height of the upper heating zone is set to h2, and the value range of the height h2 is set to 280mm≤h2≤315mm; the height of the lower heating zone is set to h3, and the value range of the height h3 is set to 120mm≤h3≤135mm.

[0014] A preferred solution is that the water cooling device includes a water-cooled copper bar, which is arranged on the outside of the furnace bottom plate, and the inlet and outlet of the water-cooled copper bar are connected to the external water inlet and outlet pipes; the electrode column at the bottom of the side heater is connected to the water-cooled copper bar through a copper electrode to achieve heat conduction.

[0015] On the other hand, a single crystal furnace is also provided, which includes a furnace body, a quartz crucible and the oxygen reduction device of the single crystal furnace thermal field, the quartz crucible is arranged in the furnace body, and the oxygen reduction device of the single crystal furnace thermal field is arranged on the periphery of the quartz crucible.

[0016] Beneficial effects:

[0017] The above-mentioned oxygen reduction device for the thermal field of a single crystal furnace and the single crystal furnace are provided with a side heater below the main heater. The side heater can reduce the SIO reaction rate at the bottom of the quartz crucible and the R arc position of the crucible during the melting process, and reduce the oxygen content in the silicon liquid; at the same time, the side heater is turned on in the melting stage of the single crystal furnace and closed in the equal-diameter stage. In the equal-diameter stage, the side heater plays a part in blocking the radiation and heat conduction of the main heater, and will absorb a part of the heat radiation from the lower part of the quartz crucible and conduct it out of the furnace, so as to reduce the heat convection at the lower part of the quartz crucible, and reduce oxygen; and the use of a water cooling device can greatly enhance the heat conduction effect of the side heater in the equal-diameter stage, so that the heat convection at the lower part of the quartz crucible is significantly suppressed, and the oxygen reduction effect is remarkable. At the same time, due to the dual performance of the side heater in blocking the radiation and heat conduction of the main heater, the crystallization effect can be greatly improved, and the production capacity of the single crystal furnace can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of an oxygen reduction device for a single crystal furnace thermal field in one embodiment;

[0019] Figure 2 A schematic diagram of a heating monomer in one embodiment;

[0020] Figure 3 Schematic diagram of the structure of the side heater in one embodiment.

[0021] Figure numerals: 1. main heater; 2. side heater; 21. heating unit; 211. upper heating zone; 2111. heating element; 2112. slit zone; 212. lower heating zone; 22. electrode column; 23. U-shaped connecting heating petal; 24. electrode foot plate; 3. water cooling device; 31. water-cooled copper busbar; 32. switch; 4. quartz crucible; 41. crucible R arc; 5. furnace bottom plate; 6. copper electrode; 7. thermal insulation felt; 8. through hole. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present application in a schematic manner, and therefore the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0024] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0025] The directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "middle", "longitudinal", "lateral", "horizontal", "inner", "outer", "radial", "circumferential" and the like in this specification are based on the directions or positional relationships shown in the drawings and are only for the convenience of simplifying the description. They do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0026] At present, the main methods of oxygen reduction include the following:

[0027] First, lower the height of the heating coil of the heater. By continuously lowering the height of the heating coil of the heater, a single crystal silicon rod with a relatively low oxygen content can be obtained. However, the height of the heating coil is reduced. To achieve the same heat as the heating coil of the original height, the heater needs to withstand a larger current, which will shorten the service life of the heater. Secondly, silicon crystal growth requires a relatively stable thermal field environment, and the longitudinal gradient should not be too large. If the height of the heating coil is reduced, the hot zone is more concentrated, and the longitudinal temperature gradient becomes larger, which is easy to cause crystal dislocation defects and affect the crystallization rate and quality of silicon single crystals.

[0028] Second, reduce the crucible rotation speed and reduce the erosion of the quartz crucible to reduce the molten oxygen generated at the position where the quartz crucible is in direct contact with the melt under high temperature. However, reducing the crucible rotation speed will affect the radial temperature gradient of the silicon melt, causing the silicon melt temperature to be unstable, affecting the crystallization of the furnace, and seriously affecting the production capacity of the single crystal furnace. At the same time, the oxygen reduction effect becomes less and less obvious after the crucible rotation speed is reduced to 5 revolutions.

[0029] Third, an insulation ring is set below the side heater and around the quartz crucible to block heat radiation, so that the heat in the single crystal furnace heat field is concentrated in the core position of the heat field dominated by the solid-liquid interface, reducing the heat radiation to the lower part of the heat field, reducing the temperature of the lower part of the heat field, reducing the heat convection of the silicon liquid in the lower part of the quartz crucible, and reducing oxygen. However, this method is easy to cause the temperature of the lower part of the heat field to be too low during the silicon material melting stage, prolonging the melting time.

[0030] Fourth, reduce the furnace pressure of the single crystal furnace, increase the argon flow rate, and precipitate as much oxygen as possible in the silicon liquid to reduce oxygen impurities in the molten liquid and reduce oxygen. However, when the furnace pressure drops to a certain level (800Pa), the liquid surface of the silicon liquid will shake more severely, seriously affecting the liquid level positioning and liquid temperature capture, causing difficulties in neck drawing. At the same time, the temperature fluctuates violently during the equal diameter process, the pulling speed fluctuates greatly, and the edge line is easy to break, which seriously affects the single crystal furnace production capacity. At the same time, as the furnace pressure continues to decrease, the oxygen reduction effect becomes less and less obvious.

[0031] Fifth, add superconducting magnetic fields on both sides of the single crystal furnace to suppress the thermal convection of the silicon liquid through the magnetic field to reduce oxygen. However, this method requires too high product investment and is not cost-effective.

[0032] In summary, the various current oxygen reduction schemes all have corresponding disadvantages, which seriously affect the production capacity of single crystal furnaces.

[0033] Therefore, in order to solve the above-mentioned problems, the embodiments of the present application provide an oxygen reduction device for the thermal field of a single crystal furnace and a single crystal furnace, which can effectively ensure the service life of the equipment and effectively improve product quality and increase the production capacity of the single crystal furnace.

[0034] The following is a detailed description of a single crystal furnace thermal field oxygen reduction device provided in this embodiment in conjunction with the accompanying drawings. Figure 1 As shown, it includes: a main heater 1, a side heater 2 and a water cooling device 3, the main heater 1 is distributed on the upper periphery of the quartz crucible 4, and is used to heat the quartz crucible 4; the side heater 2 is distributed on the lower periphery of the quartz crucible 4 and is located below the main heater 1, and the side heater 2 is at least configured to heat the quartz crucible 4 in the silicon material melting stage and be turned off in the equal diameter stage; the water cooling device 3 is connected to the side heater 2, and is configured to be started in the equal diameter stage to dissipate heat to the side heater 2.

[0035] In this embodiment, the side heater 2 is turned on in the melting stage of the single crystal furnace and turned off in the equal-diameter stage. In the equal-diameter stage, the side heater 2 can partially block the radiation and heat conduction of the main heater 1, absorb a part of the heat radiation from the lower part of the quartz crucible 4 and conduct it out of the furnace, so as to reduce the heat convection in the lower part of the quartz crucible 4 and reduce oxygen; and in the equal-diameter stage, the water cooling device 3 is used to enhance the heat conduction effect of the side heater 2 during the equal-diameter period, so that the heat convection in the lower part of the quartz crucible 4 is significantly suppressed, and the oxygen reduction effect is remarkable. At the same time, due to the dual performance of the side heater 2 in blocking the radiation and heat conduction of the main heater 1, the crystallization effect can be greatly improved, and the production capacity of the single crystal furnace can be increased.

[0036] Please continue to refer to Figure 1As shown, in this embodiment, it should be noted that the side heater 2 and the main heater 1 have a spacing △x in the height direction, and the value range of the spacing △x is set at 20-30mm. In other words, the side heater 2 is located 20-30mm below the main heater 1. A certain spacing is maintained between the side heater 2 and the main heater 1, which can play a dual role of partially blocking the main heater 1 from radiating heat and conducting heat to the lower part of the heat field, so that the lower part of the heat field can maintain a certain low temperature during the equal diameter period to suppress the heat convection at the bottom of the quartz crucible 4 to achieve the purpose of reducing oxygen, but not too cold, thereby avoiding excessive longitudinal temperature gradient of the silicon liquid in the quartz crucible 4, and excessive fluctuation of the pulling speed during the equal diameter process, which affects crystallization and even causes accidents such as crystallization and silicon leakage at the bottom of the quartz crucible 4.

[0037] Furthermore, controlling the spacing △x between the side heater 2 and the main heater 1 to 20-30mm is helpful to effectively improve the quality of the crystal rod. On the one hand, it can prevent the current from being too large due to the small spacing, causing the side heater 2 and the main heater 1 to spark, thus affecting the normal operation of the heater; on the other hand, it can prevent the side heater 2 from being too close to the bottom of the quartz crucible 4 due to the large spacing, increasing the oxygen content at the bottom, thereby affecting the oxygen reduction effect. Preferably, in this embodiment, the value of the spacing △x is: 20mm, 25mm or 30mm.

[0038] Please continue to refer to Figure 1 As shown, in this embodiment, it should be noted that the side heater 2 and the main heater 1 are both set to be cylindrical, and the inner diameter of the side heater 2 is smaller than the inner diameter of the main heater 1. In this embodiment, by setting the inner diameter of the side heater 2 to be smaller than the inner diameter of the main heater 1, the melting time can be shortened during the melting process, the reaction time of the silicon liquid and the quartz crucible 4 can be reduced, and the amount of oxygen entering the silicon liquid can be greatly reduced. Preferably, in this embodiment, the inner diameter of the side heater 2 is selected to be at least 15 mm smaller than the inner diameter of the main heater 1.

[0039] Please refer to Figure 1 , Figure 2 As shown, in some embodiments, the main heater 1 is cylindrical as a whole, and the side heater 2 adopts a splicing design. By setting the side heater 2 as a split structure, it is easy to manufacture and disassemble the side heater 2, and the cost can be greatly reduced. For example, the side heater 2 includes at least two heating units 21. In this embodiment, two heating units 21 are set as an example for explanation. The two heating units 21 are both set as arc structures with equal radius, so that the two heating units 21 can be combined into a cylindrical heating body.

[0040] In one example, the heating unit 21 is divided into an upper heating zone 211 and a lower heating zone 212, the upper heating zone 211 is set as a wide seam structure, and the lower heating zone 212 is set as an integrally connected seamless structure. It can be understood that the upper heating zone 211 includes a plurality of heating elements 2111 and a plurality of slit areas 2112, each slit area 2112 is connected to two adjacent heating elements 2111, that is, the heating elements 2111 and the slit areas 2112 are alternately connected. By increasing the seam width of the upper heating zone 211, the cross-sectional area of ​​the current passing through the upper arc petal becomes smaller, thereby increasing the resistance of the upper arc petal, thereby increasing the heat generation of the upper heating zone 211, while the lower heating zone 212 is seamlessly set, which greatly reduces the heat generation of the lower heating zone 212.

[0041] In this embodiment, the size relationship between the heating unit 21, the upper heating zone 211 and the lower heating zone 212 is also described. For example, the height of the heating unit 21 is set to h1, and the value range of the height h1 is set to 400mm≤h1≤450mm, preferably, h1 is set to 420mm; the height of the upper heating zone 211 is set to h2, and the value range of the height h2 is set to 280mm≤h2≤315mm, preferably, h2 is set to 300mm; the height of the lower heating zone 212 is set to h3, and the value range of the height h3 is set to 120mm≤h3≤135mm, preferably, h3 is set to 120mm. Among them, the height h2 of the upper heating zone 211 is equivalent to the height of the heating element 2111, and the height of the heating element 2111 is the dimension in the direction perpendicular to the arrangement direction of the multiple heating elements 2111 and the multiple slit areas 2112.

[0042] With respect to the upper heating zone 211, the plurality of slit areas 2112 have the same opening direction and are all arranged facing away from the lower heating zone 212. The width of the slit area 2112 is set to be greater than or equal to the width of the heating element 2111. It can be understood that in order to reduce the difficulty of making the heating unit 21 and simplify the difficulty of making the embryo of the heating unit 21, in this embodiment, the plurality of heating elements 2111 and the plurality of slit areas 2112 of the heating unit 21 are respectively set to have the same size parameters, that is, all the heating elements 2111 have the same size parameter, and all the slit areas 2112 also have the same size parameter; wherein, the opening depth of the slit area 2112 matches the height of at least one heating element 2111 in the upper heating zone 211. Preferably, the opening depth of all the slit areas 2112 and the height of all the heating elements 2111 are set to be the same.

[0043] As for the lower heating zone 212, the height of the lower heating zone 212 is the same as the height of the crucible R arc 41 of the quartz crucible 4. During the melting process, the positions of the lower heating zone 212 and the crucible R arc 41 are opposite to each other, which can reduce the reaction rate of the bottom of the quartz crucible 4 and the crucible R arc 41 during the melting process, thereby achieving the purpose of reducing oxygen.

[0044] Please refer to Figure 2 , Figure 3 As shown, in some embodiments, the ends of the lower heating zones 212 of the two heating monomers 21 are connected by two U-shaped connecting heating petals 23, and the two U-shaped connecting heating petals 23 are arranged opposite to each other, and the U-shaped connecting heating petals 23 are arranged horizontally perpendicular to the axis L direction of the heating monomer 21, thereby saving more space along the axis L direction of the heating monomer 21, and more layers or thicker pressing plate felts can be arranged while adapting to the original components, original assembly space and original installation method in the hot field, so that the thermal insulation of the bottom of the hot field is good, the power consumption of crystal pulling is reduced, the power of crystal induction is reduced, the thermal field has good stability, and the success rate of induction is high, which is conducive to crystal pulling.

[0045] The middle of the lower heating zone 212 is also connected to an electrode foot plate 24 , which is fixed to the lower heating zone 212 by bolts. The electrode foot plates 24 of the two heating units 21 are arranged opposite to each other.

[0046] Please refer to Figure 1 , Figure 3 As shown, in this embodiment, it is also necessary to explain that the water cooling device 3 includes a water cooling copper bar 31, the interior of the water cooling copper bar 31 has a flow channel for pure water to flow, and the water cooling copper bar 31 is arranged on the outside of the furnace bottom plate 5. It can be understood that the furnace bottom plate 5 is the bottom of the furnace body, and the inlet and outlet of the water cooling copper bar 31 are connected to the external water inlet and outlet pipelines. A heat preservation felt 7 is also arranged between the inner side of the furnace bottom plate 5 and the bottom of the quartz crucible 4, and the electrode foot plate 24 of the side heater 2 is located between the bottom of the quartz crucible 4 and the heat preservation felt 7. A through hole 8 is arranged at a position corresponding to the furnace bottom plate 5 and the heat preservation felt 7. The electrode foot plate 24 is connected to the electrode column 22 through an electrode bolt, and the lower end of the electrode column 22 extends into the through hole 8, and is connected to the external water cooling copper bar 31 through the copper electrode 6, and the water cooling copper bar 31 is electrically connected to the external power supply equipment. The heat of the side heater 2 is conducted to the copper electrode 6 through the electrode column 22, and then conducted to the water-cooled copper busbar 31 by the copper electrode 6, and then the pure water in the flow channel of the water-cooled copper busbar 31 takes away the heat for dissipation.

[0047] Preferably, a switch 32 is also provided on the water-cooling copper busbar 31, and the switch 32 can be turned on in the equal-diameter stage and turned off in other stages.

[0048] In this embodiment, the side heater 2 adopts a water-cooled copper bus 31 to enhance the heat dissipation capacity during the equal-diameter stage of the single crystal furnace. The use of the water-cooled copper bus 31 can greatly enhance the heat conduction effect of the side heater 2 during the equal-diameter period, so that the heat convection at the bottom of the quartz crucible 4 is significantly suppressed, and the oxygen reduction effect is remarkable.

[0049] Specifically, during the melting process, the side heater 2 and the main heater 1 are turned on at the same time, the power of the main heater 1 is set to 90kw, the power of the side heater 2 is set to 100kw, and the water cooling device 3 is not used. When the material block is melted to a diameter of about 200mm, the side heater 2 is turned off and the water cooling device 3 is turned on to complete the entire crystal pulling process through the processes of neck taper, shoulder release, shoulder rotation, and equal diameter. The water-cooled copper bar 31 of the water cooling device 3 is used throughout the process to achieve the effect of heat conduction, so that the lower part of the heat field is kept at a certain low temperature during the equal diameter period to suppress the heat convection at the lower part of the quartz crucible 4, so as to achieve the purpose of reducing oxygen.

[0050] In this embodiment, a single crystal furnace is also provided, which includes a furnace body, a quartz crucible 4 and the above-mentioned single crystal furnace thermal field deoxygenation device, the quartz crucible 4 is arranged in the furnace body, and the single crystal furnace thermal field deoxygenation device is arranged on the periphery of the quartz crucible 4.

[0051] The implementation principle of this embodiment is as follows: the side heater 2 is turned off in the equal-diameter stage to cool the lower part of the quartz crucible 4, a water cooling device 3 is connected to the side heater 2, and the water cooling device 3 is started in the equal-diameter stage to enhance the cooling effect, thereby reducing oxygen by reducing the heat convection in the lower part of the quartz crucible 4. In particular, combined with technical solutions such as reducing furnace pressure and increasing argon gas flow, oxygen can be further reduced.

[0052] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A deoxidation device for a single crystal furnace thermal field, characterized in that: include: A main heater (1), the main heater (1) being distributed on the upper periphery of the quartz crucible (4) and used for heating the quartz crucible (4); A side heater (2), the side heater (2) being distributed on the lower periphery of the quartz crucible (4) and located below the main heater (1); The side heater (2) is at least configured to heat the quartz crucible (4) in the silicon material melting stage and to be turned off in the equal diameter stage; A water cooling device (3), the water cooling device (3) is connected to the side heater (2) and is configured to be started in the equal diameter stage to dissipate heat from the side heater (2).

2. The oxygen reduction device for the thermal field of a single crystal furnace according to claim 1, characterized in that: The side heater (2) and the main heater (1) have a spacing △x in the height direction; The value range of the spacing △x is set to be 20-30mm.

3. The oxygen reduction device for the thermal field of a single crystal furnace according to claim 1 or 2, characterized in that: The side heater (2) and the main heater (1) are both configured to be cylindrical; The inner diameter of the side heater (2) is at least 15 mm smaller than the inner diameter of the main heater (1).

4. The oxygen reduction device for the thermal field of a single crystal furnace according to claim 3, characterized in that: The side heater (2) comprises at least two heating units (21), and the at least two heating units (21) are assembled to form a cylindrical heating body; The main heater (1) is cylindrical in shape as a whole.

5. The oxygen reduction device for the thermal field of a single crystal furnace according to claim 4, characterized in that: The heating unit (21) is divided into an upper heating zone (211) and a lower heating zone (212); The upper heating zone (211) comprises a plurality of heating elements (2111) and a plurality of slit areas (2112), each of the slit areas (2112) is connected to two adjacent heating elements (2111), and the openings of the plurality of slit areas (2112) have the same opening direction; The lower heating zone (212) is an integrated seamless structure.

6. The oxygen reduction device for the thermal field of a single crystal furnace according to claim 5, characterized in that: The opening depth of the slit area (2112) is the same as the height of at least one of the heating elements (2111) in the upper heating area (211).

7. The oxygen reduction device for the thermal field of a single crystal furnace according to claim 5, characterized in that: The height of the lower heating zone (212) is the same as the height of the crucible R arc (41) of the quartz crucible (4).

8. The oxygen reduction device for the thermal field of a single crystal furnace according to claim 6 or 7, characterized in that: The height of the heating unit (21) is set to h1, and the value range of the height h1 is set to 400mm≤h1≤450mm; The height of the upper heating zone (211) is set to h2, and the value range of the height h2 is set to 280 mm ≤ h2 ≤ 315 mm; The height of the lower heating zone (212) is set to h3, and the value range of the height h3 is set to 120mm≤h3≤135mm.

9. The oxygen reduction device for the thermal field of a single crystal furnace according to claim 1, characterized in that: The water cooling device (3) comprises a water cooling copper bar (31), the water cooling copper bar (31) is arranged on the outside of the furnace bottom plate (5), and the inlet and outlet of the water cooling copper bar (31) are connected to external water inlet and outlet pipelines; The electrode column (22) at the bottom of the side heater (2) is connected to the water-cooled copper bus (31) via a copper electrode (6) to achieve heat conduction.

10. A single crystal furnace, characterized in that: The single crystal furnace comprises a furnace body, a quartz crucible (4) and a deoxidation device for the thermal field of the single crystal furnace as described in any one of claims 1 to 9, wherein the quartz crucible (4) is arranged in the furnace body, and the deoxidation device for the thermal field of the single crystal furnace is arranged on the periphery of the quartz crucible (4).

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