Crystal furnace thermal insulation system and silicon carbide crystal growth furnace

Abstract

The invention relates to a crystal furnace heat preservation system and a silicon carbide crystal growth furnace. The crystal furnace heat preservation system comprises at least two heat insulation layers used for being arranged on the outer side of a crystal furnace heat source in a sleeving mode, and a cavity interlayer is arranged between every two adjacent heat insulation layers. The heat insulation layers are all arranged to be of a carbon / carbon composite structure and are arranged in a sleeved mode layer by layer in the heat radiation propagation direction of a heat source of the crystal furnace. And a sealing heat insulation piece is arranged between the edge of any heat insulation layer and the edge of the adjacent heat insulation layer. According to the crystal furnace heat preservation system made of the carbon / carbon composite structure, the anti-radiation capacity is improved, the temperature gradient in the crystal furnace in the heat radiation propagation direction is optimized, and the crystal furnace heat preservation system is high in structural strength, high in corrosion resistance and long in service life.

Description

Technical Field

[0001] The present application relates to the technical field of crystal furnace equipment, and in particular to a crystal furnace insulation system and a silicon carbide crystal growth furnace. Background Art

[0002] With the development of crystal furnace technology, in order to produce silicon carbide crystals, physical vapor deposition is mainly used in crystal furnaces with heat source temperatures above 2000°C. It is extremely difficult to control the gradient of the temperature field in such a high-temperature environment. In order to adapt to the above-mentioned high-temperature environment, the existing silicon carbide crystal growth furnace mainly uses soft felt or hard felt insulation materials to form an insulation system to control the temperature gradient. However, the corrosion resistance and thermal insulation performance of the existing insulation system are poor, and it is impossible to stably control the temperature field of the crystal furnace. It consumes too much energy during the production process and will affect the production quality of large-sized silicon carbide crystals. Summary of the invention

[0003] Based on this, it is necessary to provide a crystal furnace insulation system and a silicon carbide crystal growth furnace to address the defects of the crystal furnace insulation equipment.

[0004] A crystal furnace insulation system, comprising:

[0005] At least two heat-insulating layers are used to cover the outside of the heat source of the crystal furnace, and a cavity interlayer is arranged between two adjacent heat-insulating layers;

[0006] The heat insulation layers are all set to carbon / carbon composite structure, and several layers of heat insulation layers are set layer by layer along the heat radiation propagation direction of the crystal furnace heat source;

[0007] A sealing heat-insulating member is arranged between the edge of any heat-insulating layer and the edge of its adjacent heat-insulating layer.

[0008] In one embodiment, the interior of the heat insulation layer is sequentially arranged in a direction gradually away from the heat source of the crystal furnace as a first heat insulation region, a second heat insulation region and a third heat insulation region;

[0009] The carbon fiber deposition density in the first heat-insulating region is greater than that in the third heat-insulating region, and the carbon fiber deposition density in the third heat-insulating region is greater than that in the second heat-insulating region.

[0010] In one of the embodiments, a surface of the first insulation region of the insulation layer close to the heat source of the crystal furnace is covered with a densification coating.

[0011] In one of the embodiments, a heat insulating reflector is disposed in the cavity interlayer.

[0012] In one embodiment, the heat insulation layer is configured to be cylindrical, and the cylindrical heat insulation layers are sequentially sleeved.

[0013] In one embodiment, the heat insulation layer is configured to be cylindrical, and the cylindrical heat insulation layers are sequentially sleeved.

[0014] In one of the embodiments, the sealing thermal insulation member is configured as a sealing thermal insulation ring.

[0015] In one embodiment, the heat-insulating reflective member is configured as graphite paper.

[0016] In one embodiment, the thickness of each thermal insulation layer is uniform, and the first thermal insulation region, the second thermal insulation region and the third thermal insulation region are evenly distributed in the thermal insulation layer.

[0017] In one of the embodiments, a protective layer is further included, and the protective layer is arranged on the outside of the entire thermal insulation layer.

[0018] A silicon carbide crystal growth furnace comprises any one of the above-mentioned crystal furnace insulation systems.

[0019] The above-mentioned crystal furnace insulation system includes: at least two layers of insulation layers for sleeved on the outside of the crystal furnace heat source, and a cavity interlayer is arranged between two adjacent insulation layers. The arrangement of the cavity interlayer can enhance the interface reflection effect of the insulation layer. The insulation layers are all arranged as carbon / carbon composite structures, and several insulation layers are sleeved layer by layer along the heat radiation propagation direction of the crystal furnace heat source; a sealed insulation piece is arranged between the edge of any insulation layer and the edge of its adjacent insulation layer, and the sealed insulation piece can ensure that the heat reflected by the heat radiation and the insulation layer will not dissipate from between the cavity interlayers, but will propagate in the direction toward the heat source or away from the heat source, thereby optimizing the insulation effect. The present application utilizes a carbon / carbon composite structure to manufacture an insulation system, which improves the anti-radiation capability and optimizes the temperature gradient along the heat radiation propagation direction in the crystal furnace. The insulation system has high structural strength, strong corrosion resistance, and long service life.

[0020] A silicon carbide crystal growth furnace comprises the above-mentioned crystal furnace insulation system and has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a schematic structural diagram of a crystal furnace insulation system provided in an embodiment of the present application.

[0022] FIG2 is a side cross-sectional view of a crystal furnace insulation system provided in an embodiment of the present application.

[0023] FIG3 is a schematic diagram of the propagation direction of heat energy in the first crystal furnace insulation system provided in an embodiment of the present application.

[0024] FIG4 is a schematic diagram of the propagation direction of heat energy in the second crystal furnace insulation system provided in an embodiment of the present application.

[0025] FIG5 is a schematic diagram of the propagation direction of heat energy in the third crystal furnace insulation system provided in an embodiment of the present application.

[0026] Figure Number:

[0027] 1. Crystal furnace heat source; 2. Insulation layer; 2.1. First insulation area; 2.2. Second insulation area; 2.3. Third insulation area; 3. Cavity interlayer; 3.1. Sealed insulation component; 4. Densification coating; 5. Insulation reflector. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0029] In the description of the present application, it should be understood that if 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", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does 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 cannot be understood as a limitation on the present application.

[0030] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0032] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0033] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0034] Referring to Figures 1 and 2, Figure 1 is a schematic diagram of the structure of a crystal furnace insulation system provided in an embodiment of the present application. Figure 2 is a side sectional view of a crystal furnace insulation system provided in an embodiment of the present application. The crystal furnace insulation system shown includes: at least two layers of insulation layers 2 that are continuously arranged in a nested relationship, and a crystal furnace heat source 1 is arranged inside the insulation layer 2 closest to the center. For this crystal furnace heat source 1, the insulation layer 2 is used to achieve a heat preservation effect, prevent the heat energy of the crystal furnace heat source 1 from dissipating, and reflect the heat energy back to the thermal field area where the crystal furnace heat source 1 is located as much as possible. Specifically, the crystal furnace heat source 1 in the crystal furnace refers to the heat energy generated by the center.

[0035] The above-mentioned crystal furnace insulation system is provided with at least two layers of insulation layers 2, and a cavity interlayer 3 is provided between any two adjacent insulation layers 2. Each layer of the above-mentioned insulation layer 2 is provided with a carbon / carbon composite structure to ensure that the density of the carbon / carbon composite material is ≥ (1.2±0.1) g / cm 3 (g / cm3), strength ≥100MPa (megapascals), making it structurally stable. Carbon / carbon composite materials have higher density, higher strength and better processing characteristics, which significantly improve the stability and corrosion resistance of the crystal furnace insulation system.

[0036] The several layers of the above-mentioned heat insulation layers 2 are arranged layer by layer along the heat radiation propagation direction of the above-mentioned crystal furnace heat source 1, ensuring that the heat radiation propagates through at least all the heat insulation layers 2 before propagating to the outside of the crystal furnace insulation system.

[0037] The arrangement of the above-mentioned cavity interlayer 3 can enhance the interface reflection effect of the thermal insulation layer 2, ensuring that part of the heat energy emitted outward from the crystal furnace heat source 1 is more reflected back toward the crystal furnace heat source 1; the arrangement of the cavity interlayer 3 needs to ensure that there is no contact between adjacent thermal insulation layers 2.

[0038] A sealed heat insulating member 3.1 is provided between the edge of any of the above-mentioned heat insulating layers 2 and the edge of the adjacent heat insulating layer 2. The sealed heat insulating member 3.1 can ensure that the heat radiated and reflected by the heat insulating layer 2 will not dissipate from between the cavity interlayers 3, but will propagate in the direction toward the heat source 1 or away from the heat source 1, thereby optimizing the heat preservation effect.

[0039] For the heat source 1 of the crystal furnace, the heat field where the heat source 1 is located mainly transmits heat energy outward in the form of thermal radiation. When the thermal radiation contacts the interface of the thermal insulation layer 2, there are three situations, namely, the interface absorbs the thermal radiation, the thermal radiation penetrates the interface, and the interface reflects the thermal energy. The thermal insulation layer 2 is set in a multi-layer form to enhance the interface effect in the process of thermal radiation propagation, which is equivalent to reducing the heat transfer effect of thermal radiation with each additional layer of interface, thereby achieving the purpose of reducing heat transfer and improving thermal insulation performance.

[0040] In the use of some crystal furnaces, the process of producing crystals will release some corrosive gases and substances, and long-term use will continuously corrode the crystal furnace insulation system. The above-mentioned thermal insulation layer 2 is made of carbon / carbon composite material, which has higher density, better strength, and better corrosion resistance. At the same time, the production of the thermal insulation layer 2 structure can be controlled by controlling the weaving of carbon fibers, thereby controlling the carbon fiber distribution mode of the carbon / carbon composite thermal insulation layer 2, and finally realizing radial heat transfer and heat conduction control. The control method for carbon fiber distribution can be implemented according to the prior art. The present application utilizes a carbon / carbon composite structure to make a crystal furnace insulation system. The crystal furnace insulation system improves the anti-radiation capability and optimizes the temperature gradient in the crystal furnace along the direction of thermal radiation propagation of the heat source 1. The crystal furnace insulation system has high structural strength, strong corrosion resistance, and long service life.

[0041] The crystal furnace can be used for a variety of purposes such as crystal growth, crystal processing and crystal heat treatment. Any scene related to maintaining heat energy can use the crystal furnace insulation system of this application to maintain heat energy. Taking the growth of some large-sized silicon carbide crystals as an example, large-sized crystals have very high requirements for temperature stability in the crystal furnace. The crystal furnace insulation system is required to accurately control the temperature gradient and heat flow distribution to avoid temperature fluctuations from generating stress inside the crystal or increasing the probability of defects such as dislocation. At the same time, the stability of heat represents the stability of the heat energy continuously consumed by the crystal furnace, without the need to increase energy consumption, saving energy costs.

[0042] The above only exemplifies the crystal furnace insulation system in which the thermal insulation layer 2 is set to two layers. The number of thermal insulation layers 2 is set to three or more layers on the basis of meeting the setting requirements to enhance the insulation effect. In actual use, it is foreseeable that the insulation requirements and the number of structural settings of the thermal insulation layer 2 in the crystal furnace need to be taken into account, so as to change the number of thermal insulation layers 2 according to actual needs. Furthermore, the installation of the thermal insulation layer 2 can be performed step by step from the inside to the outside according to the above requirements. The specific setting method of the thermal insulation layer 2 needs to be precisely installed according to the structure of the crystal furnace. For the part of the structural installation coordination, reference can be made to the coordination method of the crystal furnace and the thermal insulation structure in the prior art, which will not be expanded in this article.

[0043] In one embodiment of the present application, with reference to Figures 3 to 5 of the specification, Figure 3 is a schematic diagram of the propagation direction of heat energy in the first crystal furnace insulation system provided in the embodiment of the present application. Figure 4 is a schematic diagram of the propagation direction of heat energy in the second crystal furnace insulation system provided in the embodiment of the present application. Figure 5 is a schematic diagram of the propagation direction of heat energy in the third crystal furnace insulation system provided in the embodiment of the present application.

[0044] The directions of the arrows in all the above figures represent the propagation directions of heat energy: the heat energy propagating in the direction away from the heat source 1 is thermal radiation, and the heat energy propagating toward the heat source 1 is the heat energy reflected back by the insulation layer 2.

[0045] In these three figures, parts of two adjacent insulation layers 2 are selected for display, so as to reflect the relative position relationship between the insulation layers 2 and the change of propagation direction of the heat source 1 after propagating to the insulation layer 2.

[0046] The interior of the thermal insulation layer 2 is sequentially arranged as the first thermal insulation area 2.1, the second thermal insulation area 2.2 and the third thermal insulation area 2.3 along the direction gradually away from the crystal furnace heat source 1. Taking advantage of the designability of the thermal conductivity of the carbon / carbon composite thermal insulation layer 2, the thermal insulation layer 2 is divided into three continuous hierarchical areas along its thickness direction. Specifically, the carbon fiber deposition density in the first thermal insulation area 2.1 is greater than the carbon fiber deposition density in the third thermal insulation area 2.3, and the carbon fiber deposition density in the third thermal insulation area 2.3 is greater than the carbon fiber deposition density in the second thermal insulation area 2.2. That is, the first thermal insulation area 2.1 is a high-density area, the second thermal insulation area 2.2 is a low-density area, and the third thermal insulation area 2.3 is a medium-density area.

[0047] When the crystal furnace insulation system is in use, the thickness direction of the heat insulation layer 2 is consistent with the propagation direction of the heat radiation.

[0048] The carbon / carbon composite material can be densified by chemical vapor deposition during the production process, thereby changing the density difference in the thickness direction. The effects provided by the layered arrangement in the above manner are as follows: the high-density deposition arrangement of the first heat-insulating region 2.1 can reduce the radiation penetration of thermal radiation, increase the reflection effect, and enhance the corrosion resistance; the low-density deposition arrangement of the second heat-insulating region 2.2 can reduce the heat transfer effect of the heat-insulating layer 2 itself and improve the thermal insulation; the medium-density deposition arrangement of the third heat-insulating region 2.3 can block the heat of thermal radiation in the direction away from the heat source 1. At the radial thickness interface of the heat-insulating layer 2, the above-mentioned layered arrangement realizes the density distribution of different radial gradients, thereby realizing the temperature gradient control of the crystal furnace. Among them, for the temperature gradient, it is preferred to keep the distribution direction of the temperature gradient consistent with the propagation direction of the thermal radiation. For example, the space formed by the innermost heat-insulating layer 2 is defined as the heat source space, and the heat source 1 is arranged in the heat source space. When the heat source space is circular, the propagation direction of the heat radiation of the internal heat source 1 is the radial direction of the circular space.

[0049] In one embodiment of the present application, a densification coating 4 is covered on the surface of the first insulation region 2.1 of the insulation layer 2 close to the crystal furnace heat source 1, and the density of the densification coating 4 is ≥1.7g / cm 3 (g / cm3). The densified coating 4 is disposed on the surface of the heat insulation layer 2 facing the heat source 1, which can improve thermal stability, optimize surface properties, enhance corrosion resistance and improve sealing.

[0050] The above-mentioned densification coating 4 can be made of various forms of densification coating materials, and the specific setting method can refer to the prior art. The combination of the densification coating 4 can make up for the relatively high porosity of the carbon / carbon composite material, reduce the penetration of gas and liquid, thereby improving the sealing, preventing impurities from invading, and ensuring the growth quality of the crystal. Similarly, a protective barrier is formed on the surface of the carbon / carbon composite material to resist the erosion of corrosive substances and extend the service life of the crystal furnace insulation system.

[0051] The densification coating 4 is at least disposed on the surface of the innermost insulation layer 2 facing the heat source 1, and may also be disposed on each insulation layer 2 facing the heat source 1. The densification coating 4 needs to completely cover the surface of the insulation layer 2 facing the heat source 1.

[0052] In one embodiment of the present application, a heat-insulating reflector 5 is disposed in the above-mentioned cavity interlayer 3, and the heat-insulating reflector 5 is disposed between two adjacent heat-insulating layers 2, and an interface reflection enhancement region A is formed between the heat-insulating reflector 5 and the heat-insulating layers 2. Assuming that two heat-insulating layers 2 are provided, the arrangement of the heat-insulating reflector 5 needs to ensure that the adjacent side surfaces of the two heat-insulating layers 2 are no longer arranged opposite to each other, and gaps are respectively provided between the heat-insulating reflector 5 and the side surfaces of the two heat-insulating layers 2, thereby forming a reflection enhancement region A.

[0053] The heat-insulating reflector 5 is made of a material that enhances the heat-insulating effect, thereby enhancing the heat-insulating effect. The heat-insulating reflector 5 can evenly conduct heat between the heat-insulating layers to make the temperature distribution more uniform. This helps to reduce the temperature gradient and avoid local overheating or overcooling. The reflection enhancement area A can reflect part of the heat, so that it returns to the vicinity of the heat source 1 or is absorbed by other heat-insulating layers 2. This can further reduce the loss of heat and improve the heat-insulating effect.

[0054] In one embodiment of the present application, the thermal insulation layer 2 is configured as a cylinder, and the thermal insulation layer 2 in the cylinder is sequentially sleeved. The thermal insulation layer 2 in the cylinder has a simple structure, is easy to produce and assemble, and is easy to arrange during the sequential sleeve process.

[0055] It should be noted that the heat insulation layer 2 is set to be cylindrical, in fact, to leave a circular hole in the middle of the cylindrical heat insulation layer 2, through which operations such as adding raw materials or observing the crystal growth process can be performed. In order to avoid the loss of heat at the open circular hole, the cylindrical heat insulation layer 2 can be adaptively provided with heat preservation, such as providing a heat preservation cover, etc., which will not be elaborated in this article.

[0056] In one embodiment of the present application, the above-mentioned sealing insulation component 3.1 is configured as a sealing insulation ring, and an annular gap is left between the layers of cylindrical insulation layers 2. The sealing insulation ring is sealed at the edge of the cylindrical insulation layer 2, thereby sealing the cavity interlayer 3.

[0057] The sealing heat-insulating member 3.1 can be installed between the edges of two adjacent heat-insulating layers 2 by riveting, but is not limited to riveting, which will not be elaborated in this article.

[0058] In one embodiment of the present application, the above-mentioned heat-insulating reflective member 5 is configured as graphite paper, and the surface of the graphite paper is smooth and has a mirror effect, which can enhance the heat reflection capability.

[0059] In one embodiment of the present application, the thickness of each layer of the thermal insulation layer 2 is consistent, and the first thermal insulation region 2.1, the second thermal insulation region 2.2 and the third thermal insulation region 2.3 are evenly distributed in the thermal insulation layer 2. In order to form a uniform temperature gradient in the crystal furnace insulation system, the thickness of each part of the thermal insulation layer 2, the opening distance of the cavity interlayer 3 between the thermal insulation layers 2, and the setting of the three thermal insulation regions in the thermal insulation layer 2 all need to be kept uniform.

[0060] In one embodiment of the present application, a protective layer is also included, and the protective layer is arranged on the outside of all the above-mentioned thermal insulation layers 2. The protective layer is used to protect the entire crystal furnace insulation system from affecting contact with other structures of the crystal furnace, and to protect the crystal furnace insulation system structure from being affected by the temperature on the thermal insulation layer 2 while ensuring the safety of the structure. After being matched with the protective layer, good thermal insulation can reduce the surface temperature of the crystal furnace and reduce heat radiation to surrounding equipment and operators. This helps to improve the safety of the working environment and reduce the risk of burns and other heat-related accidents. For the specific structure and setting method of the protective layer, reference can be made to the prior art, which will not be elaborated in this article.

[0061] A silicon carbide crystal growth furnace includes the above-mentioned crystal furnace insulation system. In the process of silicon carbide crystal growth, a temperature environment of more than 2000°C needs to be maintained, and corrosive gases will also be emitted. The crystal furnace insulation system can complete stability insulation after the temperature environment reaches the requirement, avoid temperature fluctuations, maintain the temperature environment required for crystal growth, reduce the difficulty of temperature control, and ultimately ensure the growth efficiency of the crystal. And the corrosion of the crystal furnace insulation system by corrosive gases will not destroy the heat transfer of the structure, ensure the uniformity of the temperature field, and avoid inconsistent growth conditions of crystals at different positions. In addition, the formation of a temperature gradient can promote the growth requirements of the crystal. In the process of growing silicon carbide single crystals by physical vapor transport, the transmission speed and concentration distribution of the gas phase material can be adjusted by accurately controlling the temperature gradient, thereby controlling the growth rate and quality of the crystal. Further setting of the temperature gradient also has an important influence on the morphology of the crystal. A reasonable temperature gradient can enable the crystal to maintain a good crystalline morphology during the growth process and reduce the generation of defects. If the temperature gradient is uneven or too large, it may cause defects such as polycrystalline, cracks, and dislocations in the crystal, affecting the performance and quality of the crystal.

[0062] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0063] 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 crystal furnace insulation system, characterized in that: include: At least two heat-insulating layers (2) used for covering the outside of the crystal furnace heat source (1), with a cavity interlayer (3) being provided between two adjacent heat-insulating layers (2); The heat insulation layers (2) are all configured as carbon / carbon composite structures, and several layers of the heat insulation layers (2) are arranged layer by layer along the heat radiation propagation direction of the crystal furnace heat source (1); A sealing heat-insulating component (3.1) is provided between the edge of any heat-insulating layer (2) and the edge of the adjacent heat-insulating layer (2).

2. The crystal furnace insulation system according to claim 1, characterized in that: The interior of the heat insulation layer (2) is sequentially arranged into a first heat insulation region (2.1), a second heat insulation region (2.2) and a third heat insulation region (2.3) in a direction gradually away from the crystal furnace heat source (1); The carbon fiber deposition density in the first heat insulation region (2.1) is greater than the carbon fiber deposition density in the third heat insulation region (2.3), and the carbon fiber deposition density in the third heat insulation region (2.3) is greater than the carbon fiber deposition density in the second heat insulation region (2.2).

3. The crystal furnace insulation system according to claim 2, characterized in that: A densification coating (4) is covered on the surface of one side of the first heat insulation region (2.1) of the heat insulation layer (2) close to the crystal furnace heat source (1).

4. The crystal furnace insulation system according to claim 1, characterized in that: A heat-insulating reflective component (5) is arranged in the cavity interlayer (3).

5. The crystal furnace insulation system according to claim 1, characterized in that: The heat insulation layer (2) is arranged in a cylindrical shape, and the cylindrical heat insulation layers (2) are sleeved in sequence.

6. The crystal furnace insulation system according to claim 5, characterized in that: The sealing heat-insulating component (3.1) is configured as a sealing heat-insulating ring.

7. The crystal furnace insulation system according to claim 4, characterized in that: The heat-insulating reflector (5) is configured as graphite paper.

8. The crystal furnace insulation system according to claim 2, characterized in that: The thickness of each thermal insulation layer (2) is consistent, and the first thermal insulation region (2.1), the second thermal insulation region (2.2) and the third thermal insulation region (2.3) are evenly distributed in the thermal insulation layer (2).

9. The crystal furnace insulation system according to claim 1, characterized in that: It also comprises a protective layer, which is arranged on the outside of all the thermal insulation layers (2).

10. A silicon carbide crystal growth furnace, characterized in that: A crystal furnace insulation system comprising any one of claims 1 to 9.

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