Crystal growth apparatus and method, and monocrystalline silicon rod

Abstract

Provided in the present application are a crystal growth apparatus and method, and a monocrystalline silicon rod. The crystal growth apparatus comprises: a furnace, and a crucible, a heater and a thermal insulation structure which are arranged in the furnace, wherein the heater is at least partially arranged on the side face of the crucible, and the thermal insulation structure is sleeved outside the heater; and the thickness of the thermal insulation structure in the radial direction of the furnace meets a first preset range. The crystal growth apparatus of the present application can avoid loss of energy taken away by a cooling medium, thereby achieving the aim of reducing power consumption, and reducing the pulling cost of the monocrystalline silicon rod.

Description

Crystal growth device and method and single crystal silicon rod

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on December 26, 2023, with application number 202311812414.X and entitled “A Crystal Growth Device and Method and Single Crystal Silicon Rod,” the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application belongs to the field of photovoltaic processing technology, and specifically relates to a crystal growth device, a crystal growth method, and a single crystal silicon rod. Background Art

[0004] In recent years, photovoltaic power generation, as a green energy source and a major energy source for sustainable human development, has received increasing attention and has been vigorously developed worldwide. As a fundamental material for photovoltaic power generation, single-crystal silicon wafers enjoy widespread market demand. Single-crystal silicon wafers are typically sliced ​​from single-crystal silicon ingots, which are in turn grown and drawn from silicon material. In specific applications, a single crystal furnace is typically equipped with a heater to provide heat to melt the silicon material. To facilitate operator operation outside the furnace, the furnace temperature must be controlled within a certain range.

[0005] In related technologies, a water-cooling interlayer is typically installed on the single crystal furnace body to control the temperature within an appropriate range. During operation, a cooling medium is introduced into the water-cooling interlayer according to process requirements to achieve cooling. However, although the cooling medium can be recycled, the heat in the furnace can only be dissipated into the environment during the circulation process and cannot be effectively utilized, thereby increasing the production cost of single crystal silicon rods.

[0006] Summary of the Invention

[0007] The present application aims to provide a crystal growth device, a crystal growth method and a single crystal silicon rod to solve the problems of high power consumption and high crystal pulling production cost of the crystal growth device in the related art.

[0008] In order to solve the above technical problems, this application is implemented as follows:

[0009] In a first aspect, the present application discloses a crystal growth device, which includes: a furnace body, and a crucible, a heater, and a heat preservation structure arranged in the furnace body; wherein,

[0010] The heater is at least partially arranged on the side of the crucible, and the heat-insulating structure is sheathed outside the heater;

[0011] The thickness of the heat-insulating structure along the radial direction of the furnace body meets a first preset range.

[0012] Optionally, the insulation structure includes an insulation tube and insulation felt; wherein,

[0013] The heat preservation tube is arranged outside the heater and spaced apart from the heater;

[0014] The thermal insulation felt sleeve is arranged outside the thermal insulation tube and is spaced apart from the inner side wall of the furnace body. The thickness of the thermal insulation felt along the radial direction of the furnace body meets the second preset range.

[0015] Optionally, the thermal insulation felt includes multiple layers of sub-thermal insulation felt, two adjacent layers of sub-thermal insulation felt are connected, and the overall thickness of the multiple layers of sub-thermal insulation felt meets a second preset range.

[0016] Optionally, the second preset range is 120-180 mm.

[0017] Optionally, the first preset range is 240-360 mm.

[0018] Optionally, a reflective member is provided on a side of the side wall of the furnace body adjacent to the heat insulation structure, and the reflectivity of the reflective member meets a third preset range.

[0019] Optionally, the third preset range is greater than or equal to 0.9.

[0020] Optionally, the reflector is an aluminum plate, and the aluminum plate is connected to the inner wall of the furnace body.

[0021] Optionally, the reflector is a coating provided on a side of the side wall of the furnace body adjacent to the thermal insulation felt.

[0022] Optionally, a cooling channel is further provided in the side wall of the furnace body.

[0023] In a second aspect, the present application also discloses a crystal growth method, which adopts: a furnace body and a crucible, a heater and a thermal insulation structure arranged in the furnace body; wherein the heater is at least partially arranged on the side of the crucible, and the thermal insulation structure is arranged outside the heater; the thickness of the thermal insulation structure along the radial direction of the furnace body meets the first preset range of the crystal growth device to prepare single crystal silicon rods.

[0024] Optionally, the crystal growth method comprises:

[0025] Placing silicon material in a crucible inside the furnace;

[0026] Starting the heater to heat the silicon material;

[0027] After the silicon material is melted into silicon liquid, a crystal pulling operation is performed in the silicon liquid. During the equal diameter stage of the crystal growth process, the cooling medium is stopped from being introduced into the cooling channel.

[0028] Optionally, when entering the equal diameter stage, the cooling medium is stopped from being introduced into the cooling channel, which includes:

[0029] When entering the equal diameter stage, the cooling medium is stopped from being introduced into the cooling channel, and the input power of the heater is reduced.

[0030] In a third aspect, the present application further discloses a single crystal silicon rod, which is made by the above-mentioned crystal growth method; wherein,

[0031] The oxygen content of the single crystal silicon rod is less than 10 ppma.

[0032] In the present application, since the furnace body is provided with a thermal insulation structure, and the thickness of the thermal insulation structure along the furnace body radial direction meets the first preset range, the thermal insulation structure can be used to improve the thermal insulation conditions and enhance the thermal insulation effect. Thus, by improving the thermal insulation conditions to achieve a cooling effect, during the single crystal silicon ingot drawing process, it is no longer necessary to introduce a cooling medium into the side walls of the furnace body, thereby avoiding energy loss due to the cooling medium, achieving the purpose of reducing power consumption, and lowering the cost of single crystal silicon ingot drawing.

[0033] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0035] FIG1 is a schematic structural diagram of a crystal growth apparatus according to an embodiment of the present application;

[0036] FIG2 is a schematic diagram of the heat transfer process of the crystal growth apparatus shown in FIG1 ;

[0037] FIG3 is a schematic diagram showing the relationship between the outer temperature of the side wall of the furnace shown in FIG1 and the thickness of the insulation felt;

[0038] FIG4 is a schematic diagram showing the relationship between the reflectivity of the reflector shown in FIG1 , the number of sub-insulation felt layers, and the outer temperature of the side wall of the furnace body;

[0039] FIG5 is a schematic structural diagram of a furnace body according to an embodiment of the present application;

[0040] FIG6 is a flow chart of the steps of a crystal growth method according to an embodiment of the present application.

[0041] Reference numerals: 10 - furnace body, 101 - reflector, 102 - liquid inlet, 103 - liquid outlet, 104 - liquid discharge port, 105 - air vent, 11 - crucible, 12 - heater, 13 - insulation cylinder, 14 - insulation felt. DETAILED DESCRIPTION

[0042] The embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0043] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly refer to one or more of the features. Throughout the description of this application, unless otherwise specified, "plurality" means two or more. Furthermore, "and / or" in the specification and claims refers to at least one of the connected entities, and the character " / " generally indicates an "or" relationship between the connected entities.

[0044] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0046] 1 , there is shown a schematic structural diagram of a crystal growth device according to an embodiment of the present application. As shown in FIG1 , the crystal growth device may specifically include: a furnace body 10, a crucible 11, a heater 12, and a heat-insulating structure arranged in the furnace body 10; wherein, the heater 12 is at least partially arranged on the side of the crucible 11, and the heat-insulating structure is sleeved outside the heater 12; the thickness of the heat-insulating structure along the radial direction of the furnace body 10 (the direction indicated by the arrow in FIG1 ) meets a first preset range, and the heat-insulating structure can be used to improve the heat-insulating conditions. In this way, during the drawing process of the single crystal silicon rod, there is no need to introduce a cooling medium into the side wall of the furnace body 10, thereby avoiding the defect that the heat in the furnace cannot be effectively utilized due to the heat in the furnace being dissipated into the environment during the circulation of the cooling medium, reducing the amount of heat that the heater 12 needs to provide, and thus reducing the production cost of the single crystal silicon rod.

[0047] In a specific application, there may be a certain gap between the heater 12 and the crucible 11 to avoid the problem of local excessive heat caused by the heater 12 directly heating the crucible 11. There is a certain gap between the insulation structure and the heater 12 to avoid the heater 12 directly heating the insulation structure. Optionally, the insulation structure may include an insulation tube 13 and an insulation felt 14, the insulation tube 13 is sleeved outside the heater 12 and spaced apart from the heater 12; the insulation felt 14 is sleeved outside the insulation tube 13 and spaced apart from the inner wall of the furnace body 10, and the thickness of the insulation felt 14 along the radial direction of the furnace body 10 meets the second preset range. Usually, the insulation tube 13 is also called solid felt, and the insulation felt 14 can be a flexible insulation felt.

[0048] It should be noted that in Figure 1, for the sake of convenience, only the side walls of the furnace body 10 are shown. In actual applications, as the structural body of the crystal growth device, the furnace body 10 can be a cylindrical structure, and the crucible 11, the heater 12, the insulation tube 13 and the insulation felt 14 can be arranged in sequence in the furnace body 10 from the center to the edge of the furnace body 10. The crucible 11 is mainly used to hold silicon material, and the heater 12 can be used to heat the silicon material in the crucible 11. The insulation tube 13 can be used for insulation so as to provide a thermal field environment suitable for crystal pulling. In actual applications, the insulation tube 13 can be made of materials with good insulation effect such as carbon-carbon composite materials. The insulation felt 14 can be sleeved on the outside of the insulation tube 13. In the embodiment of the present application, the insulation felt 14 can improve the insulation conditions by setting different thicknesses, thereby further improving the insulation effect.

[0049] In some optional embodiments of the present application, the first preset range is 240-360 mm, so that the insulation structure can better improve the insulation conditions in the furnace body 10. The second preset range of the thickness of the insulation felt 14 can be 120-180 mm. That is, the thickness range of the insulation tube 113 can also be 120-180 mm. In the embodiment of the present application, since the furnace body 10 is provided with an insulation tube 13 and an insulation felt 14 sleeved outside the insulation tube 13, the total thickness of the insulation tube 13 and the insulation felt 14 along the radial direction of the furnace body 10 meets the first preset range. The insulation tube 13 can be used for insulation so as to provide a thermal field environment suitable for crystal pulling, and the insulation felt 14 can be used to improve the insulation conditions, thereby improving the insulation effect.

[0050] In some optional embodiments of the present application, a reflector 101 is provided on the side wall of the furnace body 10 adjacent to the insulation structure. The reflectivity of the reflector 101 satisfies a third preset range. The reflector 101 can be used to reflect heat radiated to the inner side of the side wall of the furnace body 10 back into the furnace body 10, thereby regulating the radiation and enhancing the reflection effect. It can also further reduce the temperature outside the side wall of the furnace body 10, making it easier for operators to operate outside the furnace body 10. In this way, by improving the thermal insulation conditions to achieve a cooling effect, it is possible to prevent heat from being carried away by the cooling medium and causing energy loss, thereby achieving the purpose of reducing power consumption and lowering the cost of pulling single crystal silicon rods.

[0051] In practical applications, since the insulation felt 14 can improve thermal insulation conditions, and the reflector 101 can regulate radiation to enhance reflection, the cooperation between the insulation felt 14 and the reflector 101 eliminates the need to introduce cooling medium into the sidewalls of the furnace body 10 during the single crystal silicon ingot drawing process. This avoids the problem of heat in the furnace not being effectively utilized due to heat dissipated into the environment during the cooling medium circulation process, reduces the amount of heat required to be provided by the heater 12, and thus reduces the production cost of single crystal silicon ingots.

[0052] Referring to FIG2, a schematic diagram of the heat transfer process of the crystal growth device shown in FIG1 is shown, wherein the X-axis in FIG2 represents the coordinate diagram of each component in FIG1 along the radial direction of the furnace body 10, and the Y-axis represents the temperature distribution of each component at different positions in FIG1. ​​As shown in FIG2, the temperatures inside and outside the heat preservation tube 13 are t1 and t2 respectively, and the thickness of the heat preservation tube 13 is δ c The temperatures inside and outside the insulation felt 14 are t2 and t3 respectively, and the thickness of the insulation felt 14 is δ g The temperatures of the inner and outer sides of the side wall of the furnace body 10 are t4 and t5 respectively, and the thickness of the furnace body 10 is δ s The temperature unit is °C and the thickness unit is mm.

[0053] According to Fourier's law of heat conduction, the amount of heat conducted per unit time by the heat preservation tube 13 can be expressed as:

[0054] According to Fourier's law of heat conduction, the amount of heat conducted per unit time by the insulation felt 14 can be expressed as:

[0055] Among them, λ c can be the thermal conductivity of the insulation tube 13, λ g It can be the thermal conductivity of the insulation felt 14.

[0056] In a specific application, since heat conduction is carried out between the insulation felt 14 and the side wall of the furnace body 10 by radiation, according to the Stefan-Boltzmann law, the radiation degree between the insulation felt 14 and the side wall of the furnace body 10 can be expressed as:

[0057] q=εσ[(t3+273.15) 4 -(t4+273.15) 4 ] (Formula 3)

[0058] Where ε is the radiation coefficient and σ is the Stefan-Boltzmann constant or Stefan constant.

[0059] According to Fourier's law of heat conduction, the amount of heat conducted per unit time by the side wall of the furnace body 10 can be expressed as:

[0060] Among them, λ s It may be the thermal conductivity of the side wall of the furnace body 10 .

[0061] In the embodiment of the present application, in the process of pulling the silicon rod in the crystal growth device, in order to avoid the operation of passing the cooling medium into the side wall of the furnace body 10, the thickness δ of the insulation felt 14 is adjusted. g To improve the thermal insulation conditions inside the furnace body 10, and to adjust the radiation by adjusting the reflectivity of the reflector 101 inside the furnace body 10 to achieve the effect of enhancing reflection, the outer temperature t5 of the side wall of the furnace body 10 can be controlled to a temperature suitable for the operator to operate.

[0062] Alternatively, in actual applications, the value range of t5 can be around 44°C. This not only facilitates operation by operators outside the furnace body 10, but also makes it relatively easy to achieve this temperature without introducing a cooling medium simply by adjusting the thickness of the insulation felt 14 and cooperating with the reflector 101. This improves the feasibility of the technical solution of the embodiment of the present application and reduces power consumption during the crystal pulling process.

[0063] In some optional embodiments of the present application, the first preset range is 120-180 mm, so that the thermal insulation felt 14 can better improve the thermal insulation conditions in the furnace body 10.

[0064] In practice, the specific value of the second preset range needs to be set based on the dimensions of the furnace body 10 and the insulation tube 13. The thickness of the insulation felt 14 will vary slightly for furnace bodies 10 and insulation tubes 13 of different diameters. Generally, the larger the diameter of the furnace body 10, the larger the diameter of the insulation tube 13 within it. Accordingly, the thickness of the insulation felt 14 covering the insulation tube 13 and the external temperature of the sidewalls of the furnace body 10 will also vary slightly.

[0065] Referring to Figure 3, a schematic diagram illustrating the relationship between the outside temperature of the side wall of the furnace body shown in Figure 1 and the thickness of the insulation felt is shown. In Figure 3, the X-axis represents the thickness of the insulation felt 14, and the Y-axis represents the outside temperature t5 of the side wall of the furnace body 10. As shown in Figure 3, for furnace bodies 10 of different sizes (diameters can be 1.6 meters and 1.7 meters, respectively), the size of the insulation tube 13 is also different (the diameters of the insulation tube 13 are 32 inches and 36 inches, respectively). As the thickness of the insulation felt 14 increases, the corresponding outside temperature t5 of the side wall of the furnace body 10 shows a trend of first decreasing and then increasing. When the thickness of the insulation felt 14 is 120-180 mm, the outside temperature t5 of the side wall of the furnace body 10 can be maintained at a relatively low level.

[0066] In a specific application, when the thickness of the insulation felt 14 is less than 120 mm, the insulation effect of the insulation felt 14 is poor and it is difficult to meet the insulation requirements. When the thickness of the insulation felt 14 is greater than 180 mm, the insulation effect of the insulation felt 14 is not significantly improved and the insulation felt 14 is bulky, which is not conducive to the layout of the insulation felt 14 in the furnace body 10.

[0067] It should be noted that, in specific applications, those skilled in the art can set the thickness of the insulation felt 14 according to actual needs. For example, the thickness of the insulation felt 14 can be 120 mm, 125 mm, 130 mm, 135 mm, 140 mm, 145 mm, 150 mm, 158 mm, 160 mm, 170 mm, 180 mm, etc. The embodiment of the present application does not specifically limit the thickness of the insulation felt 14.

[0068] Optionally, the insulation felt 14 may include multiple layers of sub-insulation felt, with two adjacent layers of sub-insulation felt connected, and the total thickness of the multiple layers of sub-insulation felt along the radial direction of the furnace body 10 meets the second preset range. In practical applications, the insulation felt 14 is typically configured as multiple layers of sub-insulation felt. In this way, the sub-insulation felt is thinner and easier to process.

[0069] In a specific application, when the insulation blanket 14 is composed of multiple layers of sub-insulation blankets, two adjacent layers of sub-insulation blankets need to be connected to form a single unit. Furthermore, after the multiple layers of sub-insulation blankets are connected, the overall thickness of the multiple layers of sub-insulation blankets should fall within a second predetermined range to improve thermal insulation.

[0070] In some optional embodiments of the present application, the number of sub-insulation felt layers is 12-16, and each layer is 10-12 mm thick. In practical applications, a sub-insulation felt thickness of 10-12 mm facilitates processing. If the sub-insulation felt thickness is 10-12 mm, the number of sub-insulation felt layers can be set to 12-16, so that the overall thickness of the multi-layer sub-insulation felt meets the second preset range, thereby achieving improved thermal insulation.

[0071] It should be noted that in specific applications, the specific thickness of the sub-insulation felt and the number of sub-insulation felt layers need to be set based on actual conditions. Generally, given a given sub-insulation felt thickness, the number of sub-insulation felt layers can be determined based on the dimensions of the furnace body 10 and the insulation tube 13. The following shows the corresponding relationship between the number of sub-insulation felt layers and the dimensions of the furnace body 10 and insulation tube 13, respectively, for a sub-insulation felt thickness of 10 mm.

[0072] Table 1 Corresponding relationship between the size of furnace body and insulation tube and the number of layers of sub-insulation felt

[0073] As shown in Table 1, for a sub-insulation felt thickness of 10 mm, the optimal number of sub-insulation felt layers required to achieve optimal insulation performance varies for furnace bodies 10 and insulation tubes 13 of different sizes. For a 28-inch insulation tube 13, the optimal number of sub-insulation felt layers is 12-14; for a 32-inch insulation tube 13, the optimal number of sub-insulation felt layers is 14-16; and for a 36-inch insulation tube 13, the optimal number of sub-insulation felt layers is 14-16.

[0074] It should be noted that, in specific applications, those skilled in the art can set the specific thickness of the sub-insulation felt according to actual needs, for example, setting the thickness of the sub-insulation felt to 10 mm, 10.5 mm, 11.8 mm, or 12 mm, etc., and the thickness of each layer of the sub-insulation felt can be the same or different. Furthermore, those skilled in the art can also set the specific number of layers of the sub-insulation felt according to actual needs, for example, setting the number of layers of the sub-insulation felt to 12, 14, 15, or 16, etc. The embodiment of the present application does not specifically limit the number of layers of the sub-insulation felt.

[0075] In some optional embodiments of the present application, the insulation felt 14 may further include fixing parts; multiple layers of sub-insulation felt are sequentially wrapped around the outside of the insulation tube 13, and the fixing parts are sequentially passed through the multiple layers of sub-insulation felt to connect the multiple layers of sub-insulation felt, so as to connect the multiple layers of sub-insulation felt into a whole, thereby improving the connection reliability between the sub-insulation felts, thereby further improving the overall insulation effect of the insulation felt 14.

[0076] For example, the insulation felt 14 can be a graphite insulation felt, and the fixing part can be an iron wire. After the graphite insulation felt is wrapped around the insulation tube 13 in sequence and the overall thickness of the multiple layers of graphite insulation felt reaches the first preset range, the iron wire can be used to pass through the multiple layers of graphite insulation felt in sequence to connect the multiple layers of graphite insulation felt into a whole, so as to improve the connection reliability between the graphite insulation felts and enhance the overall insulation effect of the insulation felt.

[0077] In other optional embodiments of the present application, the third preset range is greater than or equal to 0.9, that is, the reflectivity of the reflector 101 is greater than or equal to 0.9, so that the reflector 101 has a better heat reflection effect. At the same time, since there is a difference between the reflectivity of the reflector 104 and the total reflectivity 1, the processing accuracy requirements of the reflector 104 are not too strict, so that the reflector 104 can have better processing performance to achieve the effect of regulating radiation and enhancing reflection.

[0078] In specific applications, if the reflectivity of the reflector 101 is less than 0.9, the reflector 101 has limited heat reflection effect and weak ability to regulate thermal radiation, making it difficult to achieve a good thermal insulation effect. Therefore, it is usually necessary to set the reflectivity of the reflector 101 to be greater than or equal to 0.9.

[0079] Referring to Figure 4, a schematic diagram illustrates the relationship between the reflectivity of the reflective element shown in Figure 1, the number of sub-insulation felt layers, and the external temperature of the furnace sidewall. Figure 4 shows the relationship between the reflectivity of the reflective element, the number of sub-insulation felt layers, and the external temperature of the furnace sidewall, in an application scenario with a 1.4-meter diameter furnace and a 28-inch insulation tube 13. The X-axis represents the number of sub-insulation felt layers, each layer being 10 mm thick, and the Y-axis represents the external temperature t5 of the furnace sidewall 10. As shown in Figure 4, as the number of sub-insulation felt layers increases, the corresponding external temperature t5 of the furnace sidewall 10 decreases and then increases. When the number of sub-insulation felt layers is 14-16, the external temperature t5 of the furnace sidewall can be maintained at a relatively low level. Furthermore, the greater the reflectivity ε of the reflective element 101, the lower the external temperature t5 of the furnace sidewall 101.

[0080] In actual applications, although the higher the reflectivity of the reflector 101, the better the enhanced reflection effect can be achieved by adjusting the radiation of the reflector 101, and the lower the temperature t5 of the outer side wall of the furnace body 10, the correspondingly higher the processing difficulty and cost of the reflector 101. In specific applications, when the reflectivity of the reflector 101 is greater than or equal to 0.9, the radiation of the reflector 101 can be adjusted to achieve the enhanced reflection effect, while also facilitating the processing of the reflector 101. In other words, the processing difficulty of the reflector 101 can be balanced between the heat reflection effect and the processing difficulty of the reflector 101.

[0081] For example, the reflectivity of the reflector 101 may be any one of 0.9, 0.91, 0.922 or 0.9. The embodiment of the present application does not specifically limit the emissivity of the reflector 101.

[0082] In some optional embodiments of the present application, the reflector 101 may be an aluminum plate, which may be connected to the inner sidewall of the furnace body 10 by bonding, clamping, or fastener connection. In practical applications, the aluminum plate may be a polished aluminum plate. Since the polished aluminum plate has a good reflectivity and can be directly connected to the inner side of the sidewall of the furnace body 10 in various ways, it avoids the need for structural modification of the sidewall of the furnace body 10, greatly reducing the difficulty of installing the reflector 101.

[0083] In other optional embodiments of the present application, the reflector 101 can also be a coating arranged on the side of the side wall of the furnace body 10 adjacent to the thermal insulation felt 14. The coating can be used to increase the thermal emissivity of the inner side of the side wall of the furnace body 10, and reflect the heat radiated from the thermal insulation felt 14 to the side wall of the furnace body 10 into the furnace body 10 to reduce the temperature of the side wall of the furnace body 10.

[0084] For example, the coating can be a reflective coating, which can be a nano coating, an aluminum coating, or a silver coating, etc. The embodiment of the present application does not specifically limit the specific material of the reflective coating. The reflective coating can be provided on the inner wall of the furnace body 10 by spraying, deposition, etc.

[0085] 5 , a schematic structural diagram of a furnace body according to an embodiment of the present application is shown. As shown in FIG5 , a cooling channel (not shown) is further provided in the side wall of the furnace body 10. A liquid inlet 102 is provided at one end of the cooling channel. The liquid inlet 102 can be used to pass the coolant into the cooling channel. A liquid outlet 103 is provided at the other end of the cooling channel. The liquid outlet 103 can be used to guide the coolant in the cooling channel out of the cooling channel. During the silicon melting stage of the single crystal silicon rod, due to the high temperature in the furnace body 10, a cooling medium can be introduced into the cooling channel of the side wall of the furnace body 10. By circulating the cooling medium in the cooling channel, the temperature outside the side wall of the furnace body 10 can be quickly reduced to a suitable range, so that the operator can perform related operations outside the furnace body 10.

[0086] Specifically, the cooling medium may include but is not limited to at least one of water, nitrogen, and ammonia. The embodiment of the present application may not limit the specific type of the cooling medium.

[0087] It should be noted that FIG5 only illustrates the case where the liquid inlet 102 is located at the bottom of the cooling channel and the liquid outlet 103 is located at the top of the cooling channel. In actual applications, the liquid inlet 102 may also be located at the top of the cooling channel, and the liquid outlet 103 may be located at the bottom of the cooling channel. The specific locations of the liquid inlet 102 and the liquid outlet 103 are not limited in this embodiment of the application.

[0088] As shown in FIG5 , the bottom of the furnace body 10 is further provided with a drain port 104. This drain port 104 can be located at the bottom of the furnace body 10 and connected to the liquid inlet 102. This drain port 104 can be used to discharge the cooling medium within the cooling channel. The furnace body 10 is also provided with a gas vent 105. This gas vent 105 can be located at the top of the furnace body 10 and connected to the liquid outlet 103. This gas vent 105 can be used to discharge gas within the cooling channel, further improving the cooling effect of the cooling channel.

[0089] In a specific application, the cooling channel's liquid inlet 102 may be provided with a tee connector, which is connected to the liquid inlet 102, the liquid outlet 104, and the cooling channel, respectively, to achieve connectivity among the three. Similarly, the cooling channel's liquid outlet 103 may also be provided with a tee connector, which is connected to the liquid outlet 103, the air vent 105, and the cooling channel, respectively, to achieve connectivity among the three.

[0090] In summary, the crystal growth apparatus according to the embodiment of the present application can at least include the following advantages:

[0091] In the embodiment of the present application, since the furnace body is provided with a thermal insulation structure, and the thickness of the thermal insulation structure along the furnace body radial direction meets the first preset range, the thermal insulation structure can be used to improve the thermal insulation conditions and enhance the thermal insulation effect. Thus, by improving the thermal insulation conditions to achieve a cooling effect, during the single crystal silicon ingot drawing process, it is no longer necessary to introduce a cooling medium into the side walls of the furnace body, thereby avoiding energy loss due to the cooling medium, achieving the purpose of reducing power consumption and lowering the cost of single crystal silicon ingot drawing.

[0092] An embodiment of the present application further provides a crystal growth method, which can adopt the crystal growth apparatus of any of the above embodiments to prepare single crystal silicon rods through the above crystal growth apparatus.

[0093] Specifically, the crystal growth method adopts a crystal growth device including a furnace body, a crucible, a heater and a thermal insulation structure arranged in the furnace body; wherein the heater is at least partially arranged on the side of the crucible, and the thermal insulation structure is arranged outside the heater; the thickness of the thermal insulation structure along the radial direction of the furnace body meets the first preset range to prepare single crystal silicon rods.

[0094] 6 , a flow chart of the steps of a crystal growth method according to an embodiment of the present application is shown. As shown in FIG6 , the crystal growth method may specifically include the following steps:

[0095] Step 601: Place silicon material in a crucible in a furnace body.

[0096] In the embodiments of the present application, after the crystal growth apparatus is assembled, silicon material can be added to the crucible using an external feeding device or a secondary feeder. Specifically, the silicon material can include, but is not limited to, single crystal silicon material, granular material, native multicrystalline silicon material, or re-pulled material. The embodiments of the present application do not limit the specific type of silicon material.

[0097] Step 602: Start the heater to heat the silicon material.

[0098] In the embodiment of the present application, after the silicon material is added into the crucible, a heater may be used to heat the silicon material in the crucible to melt the silicon material into silicon liquid.

[0099] In some embodiments of the present application, in order to avoid the high temperature of the side wall of the furnace body and cause harm to the operator, a cooling medium can be introduced into the cooling channel of the side wall of the furnace body after the furnace is loaded or during the silicon melting stage of the single crystal silicon rod. By circulating the cooling medium in the cooling channel, the outer temperature of the side wall of the furnace body can be quickly reduced to an appropriate range, so that the operator can perform related operations outside the furnace body.

[0100] Step 603: After the silicon material is melted into silicon liquid, a crystal pulling operation is performed in the silicon liquid. During the crystal growth process, when the crystal enters the equal diameter stage, the cooling medium is stopped from being introduced into the cooling channel.

[0101] In the embodiments of the present application, after the silicon material is melted into silicon liquid, a crystal pulling operation is performed within the silicon liquid, namely, seeding, shouldering, and equalizing operations are performed within the silicon liquid to pull a single crystal silicon rod. Specifically, during the crystal pulling operation, after entering the equalizing stage, the flow of cooling medium into the cooling channel can be stopped to reduce the temperature outside the furnace body through the thermal insulation effect of the insulation felt and reflectors.

[0102] Specifically, since the furnace body is provided with an insulation tube and an insulation felt sleeved outside the insulation tube, the thickness of the insulation tube and insulation felt along the radial direction of the furnace body meets a first preset range. The insulation felt is used to improve thermal insulation conditions and enhance the thermal insulation effect. A reflector is provided on the side of the furnace body's sidewall adjacent to the insulation felt. The reflectivity of the reflector meets a third preset range. The reflector can be used to reflect heat radiated to the inner sidewall of the furnace body back into the furnace body, thereby regulating the radiation and achieving an enhanced reflection effect, further reducing the temperature outside the sidewall of the furnace body, and facilitating operations by operators outside the furnace. In this way, by improving the thermal insulation conditions to achieve a cooling effect, energy loss caused by the cooling medium can be avoided, achieving the purpose of reducing power consumption and lowering the cost of drawing single crystal silicon rods.

[0103] Specifically, the operation of seeding can be: extending the seed crystal into the silicon liquid to draw out a thin neck of a certain length and a diameter of 3 to 5 mm to eliminate crystallization dislocations. The operation of shouldering can be: enlarging the diameter of the above-mentioned thin neck to the target diameter. When the thin neck grows to a sufficient length and reaches a certain pulling rate, the pulling speed can be reduced to release the shoulder. The operation of equal diameter can be specifically: when the crystal basically achieves equal diameter growth and reaches the target diameter, it can be pulled to form a single crystal silicon rod. In the embodiment of the present application, since the equal diameter time is long and the temperature is relatively low, it is possible to choose to stop introducing the cooling medium into the side wall of the furnace body at the equal diameter stage to take into account the crystal pulling efficiency.

[0104] Optionally, after entering the calibrating stage, the cooling medium is stopped from flowing into the cooling channel, and the heater power can be reduced, for example, from 40-50 kilowatts to 30-40 kilowatts, to achieve energy conservation. Due to the thermal insulation effect of the insulation tube and insulation blanket, even if the heater power is reduced, the furnace body can still maintain a temperature suitable for calibrating, thus achieving energy conservation.

[0105] The embodiment of the present application also provides a single crystal silicon rod, which can be made by the crystal growth method of any of the above embodiments. In the embodiment of the present application, the cooling effect is achieved by improving the thermal insulation conditions, which not only avoids the energy loss carried away by the cooling medium and achieves the purpose of saving energy consumption, but also significantly reduces the oxygen content of the single crystal silicon rod and improves the quality of the single crystal silicon rod. Experimental data show that the oxygen content of the single crystal silicon rod made by the above crystal growth method can be reduced from more than 10 ppma in the related art to less than 10 ppma. In some embodiments of the present application, the oxygen content can be 9 ppma, 8 ppma, 7 ppma, and 6 ppma. The quality of the single crystal silicon rod obtained by the device and silicon rod drawing method of the present application is significantly improved.

[0106] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0107] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A crystal growth apparatus, wherein, The crystal growth device includes: a furnace body, and a crucible, a heater, and a heat preservation structure arranged in the furnace body; wherein, At least part of the heater is arranged on the side surface of the crucible, and the heat preservation structure is sleeved outside the heater; The thickness of the heat preservation structure in the radial direction of the furnace body satisfies a first preset range.

2. The crystal growth apparatus according to claim 1, wherein, The heat preservation structure includes a heat preservation cylinder and heat preservation felt; wherein, The heat preservation cylinder is sleeved outside the heater and is arranged at an interval from the heater; The heat preservation felt is sleeved outside the heat preservation cylinder and is arranged at an interval from the inner side wall of the furnace body, and the thickness of the heat preservation felt in the radial direction of the furnace body satisfies a second preset range.

3. The crystal growth apparatus according to claim 2, wherein, The heat preservation felt includes multiple layers of sub-heat preservation felts, and adjacent two layers of the sub-heat preservation felts are connected, and the overall thickness of the multiple layers of sub-heat preservation felts satisfies the second preset range.

4. The crystal growth apparatus according to claim 2, wherein, The second preset range is 120 - 180 millimeters.

5. The crystal growth apparatus according to claim 1, wherein, The first preset range is 240 - 360 millimeters.

6. The crystal growth apparatus according to claim 1, wherein, A reflector is arranged on one side of the side wall of the furnace body adjacent to the heat preservation structure, and the reflectivity of the reflector satisfies a third preset range.

7. The crystal growth apparatus according to claim 6, wherein, The third preset range is greater than or equal to 0.

9.

8. The crystal growth apparatus according to any one of claims 6 or 7, wherein, The reflector is an aluminum plate, and the aluminum plate is connected to the inner side wall of the furnace body.

9. The crystal growth apparatus according to claim 8, wherein, The reflector is a coating arranged on one side of the side wall of the furnace body adjacent to the heat preservation felt.

10. The crystal growth apparatus according to any one of claims 1 to 9, wherein, A cooling channel is further arranged inside the side wall of the furnace body.

11. A crystal growth method, wherein, The crystal growth method adopts: a crystal growth device including a furnace body, and a crucible, a heater, and a heat preservation structure arranged in the furnace body; wherein, at least part of the heater is arranged on the side surface of the crucible, the heat preservation structure is sleeved outside the heater, and the thickness of the heat preservation structure in the radial direction of the furnace body satisfies a first preset range to prepare a single crystal rod.

12. The crystal growth method according to claim 11, wherein, The crystal growth method includes: Placing silicon material in the crucible inside the furnace body; Starting the heater to heat the silicon material; After the silicon material is melted into silicon liquid, performing crystal pulling operation in the silicon liquid, and in the equal diameter stage during crystal growth, stopping feeding the cooling medium into the cooling channel.

13. The crystal growth method according to claim 12, wherein, When entering the equal diameter stage, stopping feeding the cooling medium into the cooling channel, which includes: When entering the equal diameter stage, stopping feeding the cooling medium into the cooling channel and reducing the input power of the heater.

14. A single-crystalline silicon rod, wherein, The single crystal rod is made by using the crystal growth method according to any one of claims 11 to 13; wherein, The oxygen content of the single crystal rod is less than 10 ppma.

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