WO2023143298A1 - Device for manufacturing silicon carbide crystal and method for manufacturing silicon carbide crystal - Google Patents

Abstract

A device for manufacturing a silicon carbide crystal and a method for manufacturing a silicon carbide crystal, the device for manufacturing a silicon carbide crystal comprising a housing (1), a crucible assembly (2), a seed crystal assembly (3), a heater (4), and a graphite member (5), wherein the housing (1) defines an accommodating cavity (11), the crucible assembly (2) comprises a graphite crucible (21) and a non-graphite crucible (22), which is arranged inside the graphite crucible (21), the non-graphite crucible (22) is configured for containing a cosolvent solution, the seed crystal assembly (3) is liftably fitted in the housing (1), one end of the seed crystal assembly (3) extends into the crucible assembly (2), the seed crystal assembly (3) is configured for containing the silicon carbide crystal, the heater (4) is arranged inside the accommodating cavity (11) and around the crucible assembly (2), the graphite member (5) is liftably fitted in the housing (1), and one end of the graphite member (5) is immersed in the cosolvent solution.

Description

Device for producing silicon carbide crystal and method for producing silicon carbide crystal

This application claims the priority of the Chinese patent application with application number 202210102342.9 submitted to the China Patent Office on January 27, 2022, and the entire content of the above application is incorporated in this application by reference.

technical field

The present application relates to the technical field of silicon carbide manufacturing, for example, to a device for manufacturing silicon carbide crystals and a method for manufacturing silicon carbide crystals.

Background technique

Silicon carbide is a wide bandgap semiconductor material. Devices made of silicon carbide substrates have the advantages of high temperature resistance, high voltage resistance, high frequency, high power, radiation resistance, and high efficiency. They have important roles in radio frequency, new energy vehicles and other fields. Value.

The physical vapor transport method is a common silicon carbide crystal growth method. It heats silicon carbide powder by induction heating in a vacuum environment to sublimate it to produce reaction gases containing different gas phase components such as Si, Si2C, and SiC2. Silicon carbide single crystals are produced by solid-gas reactions. The single crystal produced by this method contains many defects such as micropipes and dislocations, which have a negative impact on the performance of silicon carbide devices.

The crystal growth of the liquid phase method is closer to the thermodynamic equilibrium conditions, which can produce higher quality silicon carbide crystals. The basic principle of the liquid phase method is: put the silicon-containing co-solvent in the graphite crucible, melt the co-solvent by induction heating, and dissolve the carbon in the graphite crucible into the co-solvent; then place the silicon carbide seed crystal in the co-solvent At the liquid level, due to the supercooling of the seed crystal, carbon precipitates on the solid-liquid interface of the seed crystal, and combines with silicon in the co-solvent to form silicon carbide crystals.

Contents of the invention

The present application proposes a device for manufacturing silicon carbide crystals.

The present application proposes a method of manufacturing silicon carbide crystals.

The present application discloses a device for manufacturing silicon carbide crystals, comprising: a housing, the housing defines an accommodating cavity; a crucible assembly, the crucible assembly includes a graphite crucible and a non-graphite crucible disposed in the graphite crucible, The non-graphite crucible is used to carry the co-solvent solution; the seed crystal assembly, the seed crystal assembly can be lifted and fitted in the housing, and one end of the seed crystal assembly extends into the crucible assembly, the seed crystal assembly The assembly is used to carry the silicon carbide crystal; the heating element is arranged in the accommodating chamber and surrounds the crucible assembly; One end of the piece is immersed in the co-solvent solution.

The present application also discloses a method for manufacturing silicon carbide crystals. The method for manufacturing silicon carbide crystals is carried out by using the device for manufacturing silicon carbide crystals described above. The method for manufacturing silicon carbide crystals includes:

Use a vacuum device to evacuate the chamber and inject inert gas;

Start the heating element to melt the co-solvent and bring the co-solvent solution to a specified temperature;

lowering the seed assembly such that the lower surface of the seed assembly contacts the co-solvent solution;

lowering the graphite member such that the graphite member is immersed in the co-solvent solution;

The seed crystal assembly is pulled to achieve silicon carbide crystal growth.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Description of drawings

Fig. 1 is a schematic structural diagram of a device for manufacturing silicon carbide crystals according to an embodiment of the present application;

Fig. 2 is the structural representation of a kind of graphite part of the embodiment of the present application;

Fig. 3 is the structural representation of another kind of graphite part of the embodiment of the present application;

Fig. 4 is a schematic flowchart of a method for manufacturing a silicon carbide crystal according to an embodiment of the present application.

Reference signs:

1. Shell; 11. Accommodating cavity; 2. Crucible assembly; 21. Graphite crucible; 22. Non-graphite crucible; 3. Seed crystal assembly; 31. Seed crystal rod; , heating element; 5, graphite element; 51, hole structure; 6, support rod; 7, crucible holder; 8, heat insulation layer.

Detailed ways

In the liquid phase method crystal growth device in the related art, the graphite crucible is not only a container for a solvent, but also a source of carbon. As the growth progresses, the graphite crucible will continue to dissolve and corrode. At the same time, it is prone to cracks due to thermal shock, resulting in a limited number of cycles, or even one-time use. The cost of high-purity graphite crucible is relatively high, which is one of the main cost components of liquid phase crystal growth. Graphite crucibles have a limited number of cycles, resulting in high crystal manufacturing costs.

In view of the above situation, embodiments of the present application provide a device for manufacturing silicon carbide crystals and a method for manufacturing silicon carbide crystals.

Embodiments of the present application will be described below in conjunction with the accompanying drawings and through specific implementation methods.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "Back","Left","Right","Vertical","Horizontal","Top","Bottom","Inner","Outer","Clockwise","Counterclockwise","Axial" , "circumferential" and so on The orientations or positional relationships shown are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, use a specific orientation construction and operation, therefore should not be construed as limiting the application.

In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of these features, which are used to describe the features differently, without order or importance. In the description of the present application, unless otherwise specified, "plurality" means two or more.

In the description of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations.

The structure of the device for manufacturing silicon carbide crystals according to the embodiment of the present application will be described below with reference to FIGS. 1-3 .

The embodiment of the present application discloses a device for manufacturing silicon carbide crystals. As shown in FIG. Out of the housing chamber 11, the crucible assembly 2 includes a graphite crucible 21 and a non-graphite crucible 22 disposed in the graphite crucible 21, the non-graphite crucible 22 is used to carry the cosolvent solution, the seed crystal assembly 3 can be lifted and fitted in the housing 1, and One end of the seed crystal assembly 3 extends into the crucible assembly 2, the seed crystal assembly 3 is used to carry the silicon carbide crystal, the heating element 4 is arranged in the accommodation chamber 11 and is arranged around the crucible assembly 2, and the graphite element 5 can be raised and lowered to fit in the housing 1, one end of the graphite piece 5 is immersed in the co-solvent solution.

It can be understood that, in the actual working process, after the heating element 4 heats the co-solvent solution in the crucible assembly 2 to a specified temperature, the seed crystal assembly 3 and the graphite component 5 are lowered to a position in contact with the co-solvent solution. The carbon in piece 5 dissolves into the co-solvent solution, and due to the supercooling of the seed crystal component 3, the carbon precipitates on the lower surface of the seed crystal component 3, and combines with the silicon in the co-solvent solution to form silicon carbide crystals. Since the crucible assembly 2 of the present embodiment includes a graphite crucible 21 and a non-graphite crucible 22 disposed in the graphite crucible 21, during the entire reaction process, the graphite crucible 21 will not undergo dissolution and corrosion, and due to the barrier of the non-graphite crucible 22 , there will be no cold and heat shock in the graphite crucible 21, which reduces the probability of cracks in the graphite crucible 21, prolongs the service life of the graphite crucible 21, thereby prolonging the replacement cycle of the graphite crucible 21 and reducing the manufacturing cost of silicon carbide crystals .

At the same time, the melting point of the non-graphite crucible 22 is slightly higher than the temperature of the co-solvent solution, and as the crystal growth time increases, the non-graphite crucible 22 may soften and deform. Therefore, if the non-graphite crucible 22 is placed in the graphite crucible 21, the shape of the graphite crucible 21 is stable at a high temperature, and the shape of the non-graphite crucible 22 can be effectively maintained, thereby avoiding the serious deformation of the non-graphite crucible 22 that cannot produce silicon carbide crystals smoothly. phenomenon occurs.

It should be added that the non-graphite crucible 22 in this embodiment refers to a crucible with a lower cost than high-purity graphite. For example, when the temperature of the co-solvent is about 1400 ° C, a quartz crucible is used, and the melting point of quartz is about 1750°C, slightly higher than the temperature of the co-solvent. For another example, the temperature of the co-solvent is about 1800°C, and a corundum crucible is used, and the melting point of corundum is about 2000°C, which is slightly higher than the temperature of the co-solvent. The non-graphite crucible 22 in this embodiment can also be made of high-melting-point metal materials such as tungsten and molybdenum that do not chemically react with the co-solvent.

In some optional embodiments, the accommodating chamber 11 has at least one air suction port and is connected to a vacuum obtaining device, which can reduce the air pressure in the accommodating chamber 11 to a desired value. The containing chamber 11 has at least one gas filling port, which can be filled with nitrogen, argon, helium or other inert gases.

In some optional embodiments, the containing chamber 11 is connected to at least one vacuum gauge. Thus, the experimenter can intuitively observe the vacuum degree in the accommodation chamber 11 .

In some optional embodiments, the co-solvent solution may also include Ti, Cr, Sc, Ni, Al, Co, Mn, Mg, Ge, As, P, N, O, B, One or more elements of Dy, Y, Nb, Nd, and Fe can be selected according to actual needs.

In some embodiments, as shown in FIG. 1 , the device for making silicon carbide crystals further includes a support rod 6 , the support rod 6 is passed through the housing 1 , and one end of the support rod 6 extends into the housing 1 and connects with the graphite piece 5 connected, and the other end protrudes from the casing 1 and is connected with the external drive mechanism. It can be understood that, since the inside of the containing cavity 11 is always at a relatively high temperature during the whole growth process, if the driving element for driving the graphite element 5 is arranged in the containing cavity 11 , it is easy to cause damage to the driving element. In this embodiment, by setting the support rod 6, the driving member that drives the support rod 6 is set as an external drive mechanism located outside the housing 1, so that the graphite member 5 will not be driven under the premise of ensuring stable crystallization. The driving parts are in a high temperature working environment, thus prolonging their service life.

FIG. 2 schematically shows a section of a part of the graphite member 5 .

In some embodiments, as shown in FIGS. 2-3 , the graphite piece 5 is ring-shaped, and the inner or outer wall of the graphite piece 5 is provided with a hole structure 51 . It can be understood that the graphite part 5 is ring-shaped and the inner and/or outer walls are provided with a hole structure 51, which can increase the contact area between the graphite part 5 and the cosolvent solution, improve the dissolution efficiency of the graphite part 5, and thereby improve the silicon carbide. manufacturing efficiency.

In some embodiments, as shown in FIGS. 2-3 , the hole structure 51 includes a plurality of grooves, the plurality of grooves are arranged at intervals along the axial and/or circumferential directions of the graphite member 5, and each groove is arranged along the graphite The circumferential or axial extension of the member 5 is set. Thus, the hole structure 51 can be processed more conveniently, which reduces the processing difficulty of the graphite piece 5 . What needs to be added here is that in other embodiments of the present application, the graphite member 5 may also be formed in a porous structure or in a shape with other hollow structures, and is not limited to the ring shape in this embodiment.

In some embodiments, the seed assembly 3 includes a seed rod 31 and a seed holder 32, the seed rod 31 is passed through the housing 1, and one end of the seed rod 31 protrudes from the housing 1 and is connected to an external drive mechanism , the other end extends into the crucible assembly 2, and the seed crystal support 32 is provided at one end of the seed rod 31 protruding into the crucible assembly 2, and the seed crystal support 32 is used to carry the growing silicon carbide crystal. It can be understood that since the interior of the chamber 11 is always at a relatively high temperature during the entire growth process, if the driver for driving the seed crystal assembly 3 is placed in the chamber 11 , the driver may be easily damaged. In this embodiment, by setting the seed crystal rod 31, the driving member for driving the seed crystal assembly 3 is set outside the housing cavity 11 to form an external driving structure. On the premise of ensuring stable crystallization, the drive will not The driving part of the seed crystal assembly 3 is in a high-temperature working environment, thereby prolonging the service life of the driving part.

In some embodiments, the seed crystal holder 32 in this embodiment may be a graphite holder or other high-temperature-resistant metal holders, which may be selected according to actual needs.

The external drive mechanism can also drive the seed rod 31 to rotate when driving the seed rod 31 up and down, so that the liquid in the crucible assembly 2 will be stirred, thereby better improving the crystallization effect. At the same time, the external drive mechanism can choose any structure that can realize linear drive and rotational drive, such as a motor driving a ball screw, a cylinder, or an electric push rod, according to actual needs, and the external drive mechanism is not limited here.

In some embodiments, the seed crystal assembly 3 further includes a seed wafer 33 disposed on the seed crystal support 32 , and the seed wafer 33 is used to support the growing silicon carbide crystal. It can be understood that setting the seed wafer 33 on the seed crystal support 32 can make the crystal form of the generated silicon carbide crystal consistent with the seed wafer, and at the same time, it is more convenient to peel the generated silicon carbide crystal from the seed crystal assembly 3 .

In some embodiments, the device for manufacturing silicon carbide crystals further includes a crucible holder 7, the crucible holder 7 is pierced on the housing 1, one end of the crucible holder 7 protrudes from the housing 1 and is connected to an external drive mechanism, and the other end is connected to the graphite The crucibles 21 are connected. It can be understood that, since the inside of the containing chamber 11 is always at a relatively high temperature during the whole growth process, if the driving part for driving the crucible assembly 2 is arranged in the containing chamber 11, the driving part may be easily damaged. In this embodiment, by setting the crucible holder 7, the driving part used for the crucible assembly 2 is arranged outside the containing chamber 11, under the premise of ensuring stable crystallization, the driving part will not be placed in a high-temperature working environment, thereby The service life of the drives of the crucible assembly 2 is extended.

The external drive mechanism can also drive the graphite crucible 21 to rotate when driving the graphite crucible 21 up and down, so that the liquid in the graphite crucible 21 will be stirred, thereby better improving the crystallization effect. At the same time, the external drive mechanism can choose any structure that can realize linear drive and rotational drive, such as a motor driving a ball screw, a cylinder, or an electric push rod, according to actual needs, and the external drive mechanism is not limited here.

In some embodiments, the heating element 4 comprises an induction heating coil formed in a helical shape. It can be understood that the induction heating coil is used for heating. During the working process, the induction heating coil passes an alternating current, An alternating magnetic field is generated, thereby generating an induced current in the graphite crucible 21 to realize heating of the graphite crucible 21, and then the heat is conducted from the graphite crucible 21 to the non-graphite crucible 22, so that the cosolvent in the non-graphite crucible 22 melts and heats up to the required temperature. Compared with the heating structure of heat conduction, in this embodiment, the induction heating coil is used for heating, the heating temperature is higher, the utilization rate of electric energy is higher, and the liquid in the graphite crucible 2 can be electromagnetically stirred.

In some embodiments, the induction heating coil is a helical tube with equal pitch, that is, the distance between two adjacent turns is a fixed value. This can improve the heating uniformity of the induction heating coil. The number of turns of the induction heating coil can be selected as 10-20 turns according to actual needs, and of course other turns can also be used.

In some embodiments, the longitudinal section of the induction heating coil is a circular ring or a rectangular ring, that is, the induction heating coil is a hollow structure, so that the induction heating coil can be cooled by water to avoid overheating of the induction heating coil. In some embodiments, the induction heating coil passes through a flexible circuit and a water circuit, and a vacuum feedthrough provided on the housing 1 , and the vacuum feedthrough is then connected to a power source and a circulating water source outside the chamber. The vacuum feedthrough can be set as a plug structure according to actual needs, which is convenient for installation and disassembly.

In some embodiments, the current frequency of the induction heating coil is 1-100 kHz.

In some embodiments, the device for manufacturing silicon carbide crystals further includes a heat insulating layer 8 , and the heat insulating layer 8 is disposed between the heating element 4 and the graphite crucible 21 and is disposed around the graphite crucible 21 . The setting of the heat insulating layer 8 can avoid the heat loss of the graphite crucible 21 .

For example, the insulating layer material is graphite felt with low thermal conductivity.

Example:

An apparatus for manufacturing a silicon carbide crystal according to an embodiment of the present application will be described below with reference to FIG. 1 .

As shown in Figure 1, the device for manufacturing silicon carbide crystals includes a housing 1, a crucible assembly 2, a seed crystal assembly 3, a graphite piece 5, a support rod 6, a crucible holder 7 and a thermal insulation layer 8, and the housing 1 defines a housing The cavity 11, the crucible assembly 2 includes a graphite crucible 21 and a non-graphite crucible 22 arranged in the graphite crucible 21, the non-graphite crucible 22 is used to carry a cosolvent solution, the support rod 6 is installed on the shell 1, and one end of the support rod 6 It extends into the casing 1 and connects with the graphite piece 5, and the other end extends out of the casing 1 and connects with the external drive mechanism. As shown in Figures 2-3, the graphite part 5 is a ring structure, and the outer or inner peripheral wall of the graphite part 5 is provided with a plurality of grooves, and the plurality of grooves are spaced along the axial and/or circumferential direction of the graphite part 5 Each groove is set along the circumferential or axial extension of the graphite member 5 . The seed crystal assembly 3 includes a seed crystal rod 31 and a seed crystal holder 32, the seed crystal rod 31 is penetrated on the housing 1, and one end of the seed crystal rod 31 protrudes from the housing 1 and is connected with an external drive mechanism, and can be driven externally Driven by the mechanism to lift and rotate, the other end of the seed rod 31 extends into the crucible assembly 2, the seed holder 32 is set at the end where the seed rod 31 extends into the crucible assembly 2, and the seed wafer 33 is located at the end of the seed holder 32. At one end of the crucible assembly 2, the seed wafer 33 is used to support the growing silicon carbide crystal. The heating element 4 is arranged in the accommodating chamber 11 and includes Included is an induction heating coil formed in a helical shape. The crucible holder 7 is mounted on the casing 1 , one end of the crucible holder 7 protrudes from the casing 1 and is connected with an external driving mechanism, and the other end is connected with a graphite crucible 21 . The heat insulation layer 8 is arranged between the heating element 4 and the graphite crucible 21 and is arranged around the graphite crucible 21 .

The flow of the method for manufacturing a silicon carbide crystal according to the embodiment of the present application will be described below with reference to FIG. 4 .

The present application also discloses a method for manufacturing silicon carbide crystals. The method for manufacturing silicon carbide crystals is carried out by using the aforementioned device for manufacturing silicon carbide crystals. The method for manufacturing silicon carbide crystals includes:

S1: using a vacuum device to evacuate the chamber 11 and inject an inert gas;

For example, first use a vacuum device to evacuate the chamber 11, so that the pressure in the chamber 11 drops to a set value, and then fill the chamber 11 with nitrogen, argon, helium or other inert gases, so that The pressure rises to the set value. Both the suction pressure and the inflation pressure can be selected according to actual needs, and the set pressure values are not limited here.

S2: Start the heating element 4 to melt the co-solvent and make the co-solvent solution reach a specified temperature;

For example, a non-contact heating element 4 (such as an induction heating coil) can be used to heat the graphite crucible 21 by an alternating current in the induction heating coil, and the heat of the graphite crucible 21 can be transferred to the non-graphite crucible 22 to make the non-graphite crucible 22 The co-solvent solution in it reaches the specified temperature. What needs to be additionally explained here is that in this embodiment, the temperature of the co-solvent solution can be detected by using an existing detection device, and there is no need to limit how to detect and control it here;

S3: lowering the seed crystal assembly 3 so that the lower surface of the seed crystal assembly 3 contacts the co-solvent solution;

For example, the lower surface of the seed crystal assembly 3 can just touch the liquid level of the co-solvent solution, and can also be immersed in a certain depth of the liquid level, so that supercooling can be better realized and carbon is precipitated, thereby being compatible with the co-solvent solution. The silicon combines to form silicon carbide crystals.

S4: lowering the graphite piece 5 so that the graphite piece 5 is immersed in the co-solvent solution;

For example, after the graphite piece 5 enters the co-solvent solution, the carbon in the graphite piece 5 will dissolve into the co-solvent.

S5: Pulling the seed crystal component 3 to realize silicon carbide crystal growth.

For example, during the process of lifting the seed crystal assembly 3 , silicon carbide crystals can continuously grow on the lower surface of the seed crystal assembly 3 .

It should be noted here that after the silicon carbide crystal growth is completed, the graphite piece 5 needs to be lifted and separated from the co-solvent solution to avoid waste of the graphite piece 5 . And at the same time turn off the heating element 4, and wait for the auxiliary solvent to cool down to the set safe temperature.

In some embodiments, in step S3, lowering the seed crystal assembly 3 can also lift the seed crystal assembly 3 so that the lower surface of the seed crystal assembly 3 is above the liquid level of the co-solvent solution, so that the seed crystal assembly 3 can be pulled out Partial co-solvent solution. It can be understood that, in this way, the lower surface of the seed crystal assembly 3 can be located Above the liquid level, due to the effect of surface tension, a part of the solution is lifted to form a meniscus, which helps the formation of silicon carbide crystals.

In some embodiments, the distance between the lower surface of the seed crystal assembly 3 and the liquid surface of the co-solvent is 0.1 mm-3 mm.

In some embodiments, when the seed crystal assembly 3 is pulled, the seed crystal assembly 3 can be driven to rotate and the crucible assembly 2 can be driven to rotate at the same time. As a result, the co-solvent solution can be shaken, thereby contributing to the formation of silicon carbide crystals.

In some embodiments, when the seed crystal assembly 3 is pulled, the graphite part 5 is driven down to maintain the liquid level of the cosolvent solution constant, and the depth at which the graphite part 5 is immersed in the cosolvent solution is increased, so that the liquid level of the cosolvent solution The height remains basically unchanged during the whole process of crystal growth, thereby ensuring the stability and consistency of the formation of silicon carbide crystals.

In the method for manufacturing silicon carbide crystals in the embodiment of the present application, since graphite parts are used as an external carbon source in the entire manufacturing method, the phenomenon of dissolution and corrosion will not occur in the graphite crucible, which reduces the probability of cracks in the graphite crucible and extends the graphite crucible. The service life of the graphite crucible is extended, and the cost of silicon carbide crystal manufacturing is reduced.

In the description of this specification, descriptions with reference to the terms "some embodiments", "other embodiments", etc. mean that specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one implementation of the present application. example or examples. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Claims (10)

A device for manufacturing silicon carbide crystals, comprising: A housing (1), the housing (1) defining an accommodating chamber (11); Crucible assembly (2), described crucible assembly (2) comprises graphite crucible (21) and the non-graphite crucible (22) that is arranged in described graphite crucible (21), and described non-graphite crucible (22) is used for carrying auxiliary solvent solution; a seed crystal assembly (3), the seed crystal assembly (3) can be lifted and fitted in the housing (1), and one end of the seed crystal assembly (3) extends into the crucible assembly (2), The seed crystal assembly (3) is used to carry silicon carbide crystals; a heating element (4), the heating element (4) is arranged in the accommodating cavity (11) and arranged around the crucible assembly (2); A graphite piece (5), the graphite piece (5) is fitted in the casing (1) in a liftable manner, and one end of the graphite piece (5) is immersed in the co-solvent solution. The device for manufacturing silicon carbide crystals according to claim 1, further comprising a support rod (6), the support rod (6) passing through the housing (1), one end of the support rod (6) The other end of the support rod (6) extends out of the casing (1) and is connected with the external driving mechanism. The device for manufacturing silicon carbide crystals according to claim 1, wherein the graphite piece (5) is annular, and at least one of the inner wall or the outer wall of the graphite piece (5) is provided with a hole structure (51) . The device for manufacturing silicon carbide crystals according to claim 3, wherein the hole structure (51) includes a plurality of grooves, and the plurality of grooves are along the axial or circumferential direction of the graphite piece (5) Arranged at intervals, each of the grooves is arranged along the circumferential or axial extension of the graphite member (5). The device for manufacturing silicon carbide crystals according to claim 1, wherein the seed crystal assembly (3) comprises: A seed rod (31), the seed rod (31) is passed through the casing (1), and one end of the seed rod (31) protrudes from the casing (1) and is connected with an external drive The mechanism is connected, and the other end of the seed rod (31) extends into the crucible assembly (2); A seed crystal holder (32), the seed crystal holder (32) is arranged at the end where the seed crystal rod (31) extends into the crucible assembly (2); A seed wafer (33), the seed wafer (33) is arranged at one end of the seed crystal holder (32) extending into the crucible assembly (2), and the seed wafer (33) is used to carry the grown silicon carbide crystal . The device for manufacturing silicon carbide crystals according to claim 1, further comprising a crucible holder (7), the crucible holder (7) is installed on the housing (1), and one end of the crucible holder (7) It protrudes from the casing (1) and is connected with an external drive mechanism, and the other end of the crucible holder (7) is connected with the graphite crucible (21). The device for manufacturing silicon carbide crystals according to claim 1, further comprising a thermal insulation layer (8), and the thermal insulation layer (8) is arranged between the heating element (4) and the graphite crucible (21) , and surround the graphite crucible (21) set up. A method for manufacturing silicon carbide crystals, the method for manufacturing silicon carbide crystals is performed using the device for manufacturing silicon carbide crystals according to any one of claims 1-7, the method for manufacturing silicon carbide crystals includes: Using a vacuum device to evacuate the chamber (11) and inject an inert gas; Start the heating element (4) to melt the co-solvent and make the co-solvent solution reach a specified temperature; lowering the seed crystal assembly (3) so that the lower surface of the seed crystal assembly (3) contacts the co-solvent solution; Lowering the graphite part (5) so that the graphite part (5) is immersed in the co-solvent solution; The seed crystal assembly (3) is pulled to realize silicon carbide crystal growth. The method for manufacturing silicon carbide crystals according to claim 8, after lowering the seed crystal assembly (3) such that the lower surface of the seed crystal assembly (3) contacts the co-solvent solution, further comprising: Pulling the seed crystal assembly (3) makes the lower surface of the seed crystal assembly (3) above the liquid level of the co-solvent solution, so that the seed crystal assembly (3) pulls out part of the co-solvent solution. solvent solution. The method for manufacturing silicon carbide crystals according to claim 8, further comprising: When the seed crystal assembly (3) is pulled, the graphite member (5) is driven down at the same time to maintain the liquid level of the co-solvent solution constant.