Silicon carbide crystal growth equipment

Abstract

The utility model discloses silicon carbide crystal growing equipment, which comprises a crystal growing furnace, a material conveying mechanism and a lifting mechanism, the inside of the crystal growing furnace comprises a quartz cover, a growing crucible and a material storage chamber, the growing crucible is positioned inside the quartz cover, and heat preservation cotton is filled between the growing crucible and the quartz cover. An electromagnetic induction coil is wound outside the quartz cover, the quartz cover is mounted at the upper part of the storage chamber, the storage chamber is mounted at the bottom of the crystal growth furnace, and seed crystals are mounted on the inner surface of a crucible cover of the growth crucible; the material conveying mechanism penetrates through the material storage chamber and the growth crucible and is used for conveying powder in the material storage chamber into the growth crucible; and the lifting mechanism is positioned outside the crystal growth furnace, is connected with the electromagnetic induction coil in the crystal growth furnace and is used for controlling the lifting of the electromagnetic induction coil. According to the utility model, new powder can be added in the crystal growth process, the crystal growth thickness is increased, and the utilization rate of the powder and the crystal growth quality are improved at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a silicon carbide crystal growth device. Background Art

[0002] At present, there are various thermal field devices for growing silicon carbide crystals on the market. Inside the thermal field device for crystal growth, the temperature of the crystallization interface, the crystallization driving force, and the crystal growth rate are constantly changing throughout the growth process. However, in the existing partial crucible structures during the crystal growth process, due to the continuous reduction of raw materials, raw materials cannot be continuously output into the crucible. On the one hand, it affects the stability of the reaction and causes uneven crystallization; on the other hand, it affects the growth quality and thickness of the silicon carbide crystal. Secondly, as the crystal thickness increases, the distance between the crystal growth interface and the powder source surface gradually decreases, that is, the crystal growth interface gradually moves towards the region with higher temperature at the bottom, resulting in a significant reduction in the axial temperature gradient between the crystal growth interface and the powder surface, reducing the crystal growth rate and affecting the crystal growth quality at the same time. Summary of the Invention

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. For this reason, the utility model provides a silicon carbide crystal growth device, which can add new powder during the crystal growth process, increase the thickness of crystal growth, improve the utilization rate of the powder and the crystal growth quality at the same time.

[0004] The utility model also provides a silicon carbide crystal growth device, including a crystal growth furnace, a feeding mechanism, and a lifting mechanism. The interior of the crystal growth furnace includes a quartz cover, a growth crucible, and a storage chamber. The growth crucible is located inside the quartz cover, and heat insulation cotton is filled between the growth crucible and the quartz cover. An electromagnetic induction coil is wound around the outside of the quartz cover. The quartz cover is installed above the storage chamber, and the storage chamber is installed at the bottom of the crystal growth furnace. A seed crystal is installed on the inner surface of the crucible cover of the growth crucible. The feeding mechanism penetrates through the storage chamber and the growth crucible and is used to convey the powder in the storage chamber into the growth crucible. The lifting mechanism is located outside the crystal growth furnace and is connected to the electromagnetic induction coil inside the crystal growth furnace and is used to control the lifting of the electromagnetic induction coil. Both the feeding mechanism and the lifting mechanism are electrically connected to the crystal growth furnace control system.

[0005] In the above technical solution, silicon carbide powder is placed in the growth crucible for the growth of silicon carbide crystals. The storage chamber is filled with silicon carbide powder. During operation, the electromagnetic induction coil, the servo motor, and the lifting mechanism work simultaneously. The electromagnetic induction coil is used to heat the growth crucible. When the temperature in the crystal growth furnace reaches a certain temperature value, the silicon carbide powder in the growth crucible starts to volatilize and rises to the surface of the silicon carbide seed crystal for crystallization.

[0006] The feeding mechanism rotates. On the one hand, it stirs the powder in the growth crucible, effectively preventing the formation of ceramic bodies at the center top of the powder in the growth crucible, improving the utilization rate of the powder, and thus increasing the thickness of the crystal. On the other hand, the feeding mechanism can transport the powder in the storage chamber to the growth crucible, replenish new powder into the growth crucible, and further increase the thickness of the crystal.

[0007] The lifting mechanism mainly controls the electromagnetic induction coil to move downward at a set rate during crystal growth, ensuring that the axial temperature gradient between the crystal growth interface and the powder surface is always within the set range, avoiding a large reduction in the axial temperature gradient, which affects the growth rate and quality of the crystal. Although the downward movement of the electromagnetic induction coil will cause the high-temperature zone of the entire thermal field to move downward, further aggravating the formation of ceramic bodies at the center top of the powder in the growth crucible, due to the fact that the feeding rod and the graphite disk of the present invention are always in a rotating state and continuously stir the powder, therefore, when the equipment of this embodiment is used, the powder in the growth crucible will not form ceramic bodies, improving the utilization rate of the powder and being beneficial to the increase of the crystal thickness.

[0008] In some embodiments, the feeding mechanism of the present invention includes a servo motor and a feeding rod. The servo motor is fixedly installed at the bottom of the crystal growth furnace; the bottom of the feeding rod penetrates the bottom wall of the crystal growth furnace and is connected to the output end of the servo motor. Its top extends upward through the top wall of the storage chamber and the bottom wall of the growth crucible to the inner cavity of the growth crucible. The outer surface of the feeding rod is provided with a feeding groove, and the servo motor is connected to the control system of the crystal growth furnace. In this embodiment, the feeding rod transports the powder in the storage chamber to the growth crucible through the feeding groove to replenish the powder in the growth crucible, increasing the thickness of the crystal. At the same time, the feeding rod has a stirring effect on the powder, preventing the formation of ceramic bodies at the center top of the powder in the growth crucible, thereby improving the utilization rate of the powder and being beneficial to the increase of the crystal thickness.

[0009] In some embodiments, a graphite disk is installed at the top of the feeding rod of the present invention for stirring the powder inside the growth crucible. In this embodiment, the graphite disk is mainly used for stirring the powder to prevent the formation of ceramic bodies at the center top of the powder, improving the utilization rate of the powder and increasing the thickness of the silicon carbide crystal.

[0010] In some embodiments, the lifting mechanism of the present utility model includes a lifting box. A AC motor is fixedly connected to the bottom of the lifting box. The output end of the AC motor is fixedly connected to a threaded rod. The top of the threaded rod penetrates through the lifting box and is movably connected to the top of the inner cavity of the lifting box through a bearing. A moving plate is sleeved on the surface of the threaded rod in a threaded manner. A guiding rod is fixedly connected to the left side of the inner cavity of the lifting box. The moving plate is movably sleeved on the outer surface of the guiding rod. The AC motor is electrically connected to the crystal growth furnace control system; it further includes a connecting rod. One end of the connecting rod is fixed on the upper surface of a connecting plate, and the other end passes through the lifting box and the top of the crystal growth furnace and is connected to an electromagnetic induction coil. In this embodiment, the AC motor controls the operation of the threaded rod to drive the moving plate to move upward or downward, thereby controlling the electromagnetic induction coil to move downward or upward. The guiding rod in this embodiment mainly plays a guiding role for the moving plate, ensuring that the moving plate always moves horizontally upward or downward during the moving process.

[0011] In some embodiments, the present utility model further includes a bottom plate. Three support columns are evenly distributed at the bottom of the crystal growth furnace. Support columns are installed at the four corners of the bottom of the lifting box. The crystal growth furnace and the lifting box are fixed on the bottom plate through the support columns.

[0012] Additional aspects and advantages of the present utility model will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of a silicon carbide crystal growth device according to an embodiment of the present utility model;

[0014] Figure 2 is a schematic diagram of a silicon carbide crystal growth device according to an embodiment of the present utility model;

[0015] Figure 3 is a schematic diagram of a silicon carbide crystal growth device according to an embodiment of the present utility model;

[0016] REFERENCE NUMERALS:

[0017] 1000: Silicon carbide growth device

[0018] 100: Crystal growth furnace; 10: Quartz cover; 101 Support column; 20: Thermal insulation cotton; 30: Growth crucible; 40: Seed crystal; 50: Powder; 60: Feeding rod; 601: Feeding groove; 602: Graphite disk; 603: Servo motor; 70: Electromagnetic induction coil; 80: Storage chamber;

[0019] 200: Lifting mechanism; 201: Lifting box; 202: Threaded rod; 203: Moving plate; 204: Guide rod; 205: Connecting rod; 206: AC motor.

[0020] 300: Bottom plate. Detailed implementation manner

[0021] The embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present utility model, and should not be construed as a limitation to the present utility model.

[0022] The following disclosure provides many different embodiments or examples for implementing different structures of the present utility model. To simplify the disclosure of the present utility model, components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present utility model. In addition, the present utility model may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present utility model provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the applicability of other processes and / or the use of other materials.

[0023] The following reference Figures 1 to 3 Describe a silicon carbide growth device 1000 according to an embodiment of the present utility model, including a crystal growth furnace 100, a feeding mechanism, and a lifting mechanism 200; the interior of the crystal growth furnace 100 includes a quartz cover 10, a growth crucible 30, and a storage chamber 80. The growth crucible 30 is located inside the quartz cover 10. Heat-insulating cotton 20 is filled between the growth crucible 30 and the quartz cover 10. An electromagnetic induction coil 70 is wound around the outside of the quartz cover 10 for heating the growth crucible 30. The quartz cover 10 is installed above the storage chamber 80, the storage chamber 80 is installed at the bottom of the crystal growth furnace 100, and a seed crystal 40 is installed on the inner surface of the crucible cover of the growth crucible 30. The feeding mechanism penetrates through the storage chamber 80 and the growth crucible 30 for transporting the powder material 50 in the storage chamber 80 into the growth crucible 30. The lifting mechanism 200 is located outside the crystal growth furnace 100 and is connected to the electromagnetic induction coil 70 inside the crystal growth furnace 100 for controlling the lifting of the electromagnetic induction coil 70. The feeding mechanism, the lifting mechanism 200, and the electromagnetic induction coil 70 are all electrically connected to the control system of the crystal growth furnace 100.

[0024] Specifically, the feeding mechanism in this embodiment is coaxially arranged with the growth crucible 30. In the working chamber of the crystal growth furnace 100, when the feeding mechanism rotates, on the one hand, it stirs the powder material 50 in the growth crucible 30 to prevent the formation of a ceramic body at the top center of the powder material 50, improving the utilization rate of the powder material 50, thereby increasing the thickness of the crystal. On the other hand, as shown in Figure 2 , the feeding mechanism transports the powder material 50 in the storage chamber 80 to the growth crucible 30 to supplement the powder material 50 in the growth crucible 30, adding raw materials for crystal production, and thus increasing the thickness of crystal growth. In this embodiment, the lifting mechanism 200 controls the lifting of the electromagnetic induction coil 70. During the crystal growth process, the lifting mechanism 200 controls the electromagnetic induction coil 70 to move downward at a certain rate, effectively preventing the reduction of the axial temperature gradient between the crystal growth interface and the surface of the powder material 50, which is beneficial to reducing the defects in the crystal and improving the growth quality of the crystal.

[0025] During the crystal growth process, the downward movement of the electromagnetic induction coil 70 will cause the high-temperature area of the entire thermal field to move downward, thus aggravating the formation of the ceramic body at the top center of the powder material 50 in the growth crucible 30. However, in this embodiment, the feeding rod 60 and the graphite disk 602 are always in a rotating state, continuously stirring the powder material 50 in the growth crucible 30. Therefore, no ceramic body will be formed at the top center of the powder material 50, improving the utilization rate of the powder material 50 and being beneficial to the increase of the crystal thickness.

[0026] In some embodiments, as shown in Figure 2 , the feeding mechanism of the present utility model includes a servo motor 603 and a feeding rod 60. Specifically, the servo motor 603 is electrically connected to the control system of the crystal growth furnace 100, and the control system of the crystal growth furnace 100 controls the servo motor 603 to work or stop working. The servo motor 603 is fixedly installed at the bottom of the crystal growth furnace 100; the bottom of the feeding rod 60 penetrates through the bottom wall of the crystal growth furnace 100 and is connected to the output end of the servo motor 603, and its top extends upward through the top wall of the storage chamber 80 and the bottom wall of the growth crucible 30 to the inner cavity of the growth crucible 30. The outer surface of the feeding rod 60 is provided with a feeding groove 601. In this embodiment, the servo motor 603 controls the rotation of the feeding rod 60, and transports the powder material 50 in the storage chamber 80 to the growth crucible 30 through the feeding groove 601 on the feeding rod 60 to supplement the powder material 50 in the growth crucible 30.

[0027] In some embodiments, a graphite disk 602 is installed at the top of the feeding rod 60 of the present utility model for stirring the powder material 50 inside the growth crucible 30. Since the stirring area of the graphite disk 602 is relatively large, therefore, it further effectively prevents the phenomenon of the formation of a ceramic body at the top center of the powder material 50 in the growth crucible 30, improves the utilization rate of the powder material 50, and increases the thickness of the crystal.

[0028] In some embodiments, the lifting mechanism 200 of the present utility model includes a lifting box 201. A bottom of the lifting box 201 is fixedly connected to an AC motor 206. An output end of the AC motor 206 is fixedly connected to a threaded rod 202. A top of the threaded rod 202 penetrates through the lifting box 201 and is movably connected to a top of an inner cavity of the lifting box 201 through a bearing. A moving plate 203 is sleeved on a surface of the threaded rod 202 in a threaded manner. A guiding rod 204 is fixedly connected to a left side of the inner cavity of the lifting box 201. The moving plate 203 is movably sleeved on an outer surface of the guiding rod 204; further includes a connecting rod 205. One end of the connecting rod 205 is fixed on an upper surface of a connecting plate, and the other end passes through the lifting box 201 and a top of the crystal growth furnace 100 and is connected to an electromagnetic induction coil 70. Specifically, one end of the connecting rod 205 extends upward out of the lifting box 201, then extends into the crystal growth furnace 100 from the top of the crystal growth furnace 100 and is connected to the electromagnetic induction coil 70. The AC motor 206 is electrically connected to a control system of the crystal growth furnace 100. The control system of the crystal growth furnace 100 controls the AC motor 206 to work or stop working, thereby controlling the lifting of the connecting rod 205, and further controlling the lowering or rising of the electromagnetic induction coil 70. In this embodiment, the AC motor 206 is used to control the rotation of the threaded rod 202, and the threaded rod 202 drives the moving plate 203 to rise or fall, thereby controlling the lowering or rising of the electromagnetic induction coil 70 through the connecting rod 205.

[0029] In some embodiments, the present utility model further includes a bottom plate 300 (not shown in the figure). Three support columns 101 are evenly distributed at a bottom of the crystal growth furnace 100. Four corners of a bottom of the lifting box 201 are each provided with a support column 101. The crystal growth furnace 100 and the lifting box 201 are fixed on the bottom plate 300 through the support columns 101. In this embodiment, the crystal growth furnace 100 and the lifting mechanism 200 are fixed on the floor through the support columns 101, which is convenient for overall movement.

[0030] In some embodiments, referring to Figure 3 as shown, a longitudinal section of the material storage chamber 80 of the present utility model is a conical structure, which is convenient for the powder material 50 to be concentrated at the bottom of the material storage chamber 80, thereby maximizing the utilization of the powder material 50 inside the material storage chamber 80.

[0031] During operation, the control system of the crystal growth furnace 100 controls the electromagnetic induction coil 70 to heat, and starts the servo motor 603 and the AC motor 206 to work simultaneously.

[0032] The electromagnetic induction coil 70 heats up, and the temperature inside the crystal growth furnace 100 rises. When the temperature inside the furnace rises to a certain temperature, the silicon carbide powder material 50 in the growth crucible 30 starts to volatilize upward and rises to the surface of the silicon carbide seed crystal 40 for crystallization.

[0033] The servo motor 603 operates to drive the material conveying rod 60 to rotate. The graphite disk 602 at the top of the material conveying rod 60 rotates accordingly. The material conveying rod 60 stirs the powder material 50 with the graphite disk 602, effectively preventing the formation of a ceramic body at the top center of the powder material 50 during the crystal growth process, improving the utilization rate of the powder material 50, and thus increasing the thickness of crystal growth. While the material conveying rod 60 is rotating, the spiral material conveying groove 601 on its surface will be filled with the powder material 50. Refer to Figure 2 As shown, when the material conveying groove 601 is exposed above the surface of the powder material 50, the powder material 50 in the material conveying groove 601 located above the surface of the powder material 50 will fall into the growth crucible 30 to supplement the powder material 50 in the growth crucible 30, that is, to add new powder material 50 into the growth crucible 30. Since the material conveying rod 60 continuously transports the powder material 50 in the storage chamber 80 to the growth crucible 30, therefore, the thickness of the silicon carbide crystal is further increased.

[0034] During the crystal growth process, in order to avoid the downward movement of the crystal growth interface, resulting in a significant reduction in the axial temperature gradient between the crystal growth interface and the surface of the powder material 50, refer to Figure 2 As shown, the AC motor 206 of the present invention operates to drive the threaded rod 202 to rotate. The rotation of the threaded rod 202 drives the moving plate 203 to move upward, causing the electromagnetic induction coil 70 to slowly move downward at a rate of 0.1 mm / h, ensuring that the axial temperature gradient between the crystal growth interface and the surface of the powder material 50 always remains within the set range, and there will be no significant reduction in the axial temperature gradient, thereby ensuring the stability of crystal growth and further ensuring the quality of crystal growth. And because the material conveying rod 60 and the graphite disk 602 are in a rotating state throughout the crystal growth process and continuously stir the powder material 50, therefore, there will be no phenomenon of the formation of a ceramic body at the top center of the powder material 50 in the growth crucible 30 due to the downward movement of the electromagnetic induction coil 70.

[0035] Other components of the silicon carbide growth device 1000 according to the embodiments of the present invention, such as the growth crucible 30 and the electromagnetic induction coil 70, etc., and the operations are known to those of ordinary skill in the art and will not be described in detail here.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation on the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, the meaning of "a plurality of" is two or more unless otherwise specifically defined.

[0038] In the present utility model, unless otherwise clearly specified and defined, terms such as "installed", "connected", "joined", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or a communication connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0039] In the present utility model, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0040] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations 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 a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0041] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present utility model, and the scope of the present utility model is defined by the claims and their equivalents.

Claims

1. A silicon carbide crystal growth device, characterized in that: include A crystal growth furnace, wherein the interior of the crystal growth furnace includes a quartz cover, a growth crucible and a storage chamber, the growth crucible is located inside the quartz cover, the space between the growth crucible and the quartz cover is filled with heat insulation cotton, the outside of the quartz cover is surrounded by an electromagnetic induction coil, the quartz cover is installed on the upper part of the storage chamber, the storage chamber is installed at the bottom of the crystal growth furnace, and a seed crystal is installed on the inner surface of the crucible cover of the growth crucible; A material conveying mechanism, which passes through the material storage chamber and the growth crucible and is used to convey the powder in the material storage chamber to the growth crucible; A lifting mechanism, which is located outside the crystal growth furnace and is connected to the electromagnetic induction coil inside the crystal growth furnace, and is used to control the lifting and lowering of the electromagnetic induction coil; The feeding mechanism and the lifting mechanism are both electrically connected to the crystal growth furnace control system.

2. A silicon carbide crystal growth device according to claim 1, characterized in that: The feeding mechanism comprises a servo motor, which is fixedly mounted at the bottom of the crystal growth furnace and electrically connected to the crystal growth furnace control; A feed rod, the bottom of which passes through the bottom wall of the crystal growth furnace and is connected to the output end of the servo motor, and the top of which passes through the top wall of the storage chamber and the bottom wall of the growth crucible upward and extends to the inner cavity of the growth crucible, and a feed trough is provided on the outer surface of the feed rod.

3. A silicon carbide crystal growth device according to claim 2, characterized in that: A graphite disk is installed on the top of the feeding rod for stirring the powder inside the growth crucible.

4. The silicon carbide crystal growth device according to claim 1, characterized in that: The lifting mechanism includes a lifting box, an AC motor is fixedly connected to the bottom of the lifting box, a threaded rod is fixedly connected to the output end of the AC motor, the top of the threaded rod passes through the lifting box, and is movably connected to the top of the inner cavity of the lifting box through a bearing, a movable plate is threadedly sleeved on the surface of the threaded rod, a guide rod is fixedly connected to the left side of the inner cavity of the lifting box, the movable plate is movably sleeved on the outer surface of the guide rod, and the AC motor is electrically connected to the crystal growth furnace control system; It also includes a connecting rod, one end of which is fixed to the upper surface of the connecting plate, and the other end of which passes through the lifting box and the top of the crystal growth furnace and is connected to the electromagnetic induction coil.

5. The silicon carbide crystal growth device according to claim 4, characterized in that: It also includes a bottom plate. Three support columns are evenly distributed on the bottom of the crystal growth furnace. Support columns are installed at the four corners of the bottom of the lifting box. The crystal growth furnace and the lifting box are fixed to the bottom plate through the support columns.

6. The silicon carbide crystal growth device according to claim 1, characterized in that: The longitudinal section of the storage chamber is a conical structure.

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