Silicon carbide crystal growth device with stable growth rate

Abstract

The utility model discloses a silicon carbide crystal growth device with a stable growth rate, which comprises a crucible body, a crucible cover and a gas phase component adjusting component, and the crucible body defines a containing cavity with an open top; the crucible cover is arranged at the top end of the crucible body, and seed crystals are arranged at the bottom of the crucible cover; the gas-phase component adjusting assembly is arranged in the middle of the crucible body, and the gas-phase component adjusting assembly is used for adjusting a conveying channel of gas-phase components in the crucible body so as to maintain the growth rate of crystals in the whole growth stage. According to the silicon carbide crystal growth device with the stable growth rate, the flowing gas transmission rate which is gradually increased in the crystal growth process can be maintained, so that the diffusion efficiency is increased, and the problem that the growth rate is reduced due to temperature attenuation in the later stage of a thermal field is solved; the stability of the growth rate in the whole growth stage (especially in the middle and later periods) of the crystal is maintained, and the effective thickness of the crystal is increased.

Description

Technical Field

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

[0002] Currently, the price gap between silicon carbide substrates and traditional products continues to narrow, and their application penetration is accelerating. The main factors affecting the price decline of 6-inch silicon carbide substrates are: 1) the continued expansion of 6-inch substrate production capacity and increased supply capacity; 2) the stabilization of 6-inch substrate mass production technology at some domestic wafer fabs, significantly improved yield rates, and continued capacity expansion, driving down market prices; 3) with the entry of more mass production companies, intensified industry competition, leading to further price declines. As of June 2024, the lowest price for MOS-grade and P-grade substrates has fallen below 3,500 yuan per piece.

[0003] Substrates are made from silicon carbide single crystals through a series of processes, including cutting, grinding, and cleaning. The high cost of silicon carbide single crystals is a major constraint on the large-scale application and development of various silicon carbide semiconductor devices. To reduce the cost of silicon carbide single crystals, increasing their thickness while maintaining stable crystal growth and processing yields is an effective approach. Increasing the effective thickness of the crystals and improving single ingot yield fundamentally address the unit cost manufacturing issue. To maintain product competitiveness, we must fundamentally enhance our understanding of current and future technologies and focus on increasing the effective thickness of high-quality 6-inch crystals.

[0004] However, the main reasons why traditional crystals cannot grow thicker are:

[0005] 1) Powder loading: Usually, in order to maintain a reasonable axial and radial temperature gradient in the thermal field, the powder loading is fundamentally limited, resulting in an inability to provide a sufficient growth atmosphere for the crystal. Even if the powder loading of the crucible is greatly increased, if the power, temperature and coil position are not matched, the excess silicon carbide powder cannot be converted into the effective sublimation part.

[0006] 2) Temperature maintenance: Due to the inherent properties of thermal insulation felt, long-term, high-temperature crystal growth inevitably leads to a decrease in thermal insulation performance. As a result, the temperature is high in the early stages of crystal growth, resulting in a rapid growth rate. However, the temperature decay in the middle and late stages of crystal growth cannot provide sufficient driving force for growth. In other words, the crystal growth rate continuously decreases during the growth process. This limits the effective thickening of the crystal in the later stages of growth due to the reduced growth rate. Summary of the Invention

[0007] The present utility model aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present utility model provides a silicon carbide crystal growth device with a stable growth rate, which can maintain the gradually increasing flow gas transmission rate during the crystal growth process, thereby increasing the diffusion efficiency, compensating for the problem of reduced growth rate caused by temperature attenuation in the later stage of the thermal field, maintaining the stability of the growth rate throughout the entire growth stage (especially in the middle and later stages) of the crystal, and increasing the effective thickness of the crystal.

[0008] The silicon carbide crystal growth device with a stable growth rate according to an embodiment of the present utility model includes:

[0009] A crucible body, the crucible body defining a receiving cavity with an open top;

[0010] A crucible cover, the crucible cover being provided at the top end of the crucible body, and a seed crystal being provided at the bottom of the crucible cover;

[0011] A gas phase component adjusting assembly, the gas phase component adjusting assembly being provided in the middle of the crucible body, and the gas phase component adjusting assembly being used to adjust the transport channel of the gas phase components in the crucible body to maintain the growth rate throughout the entire growth stage of the crystal.

[0012] For the silicon carbide crystal growth device with a stable growth rate according to the present utility model, according to the crystal growth stage, the gas phase component adjusting assembly is controlled to realize the control of the cross-sectional area of the transport channel, maintain the gradually increasing flow gas transmission rate during the crystal growth process, thereby increasing the diffusion efficiency, compensating for the problem of reduced growth rate caused by temperature attenuation in the later stage of the thermal field, maintaining the stability of the growth rate throughout the entire growth stage (especially in the middle and later stages) of the crystal, and increasing the effective thickness of the crystal.

[0013] In some embodiments of the present utility model, the gas phase component adjusting assembly includes:

[0014] A graphite plate, the graphite plate being provided on the inner side wall of the crucible body, and a first through hole penetrating the graphite plate being provided at the center of the graphite plate;

[0015] A shielding assembly, the shielding assembly being movably provided on the graphite plate;

[0016] A power mechanism, the power mechanism being connected to the shielding assembly and used to control the shielding assembly to move along the radial direction of the crucible body;

[0017] Wherein, the shielding assembly and the graphite plate jointly define the transport channel of the gas phase components, and by controlling the position of the shielding assembly, the adjustment of the cross-section of the gas phase component delivery channel is realized.

[0018] In some embodiments of the present utility model, the shielding assembly includes a plurality of shielding plates evenly distributed circumferentially along the inner periphery of the crucible body. The shielding plates have at least a first working state and a second working state. In the first working state, the shielding plates are completely moved above the graphite plate so that the first through hole is completely exposed. In the second working state, the shielding plates are moved to the first through hole so that at least a part of the first through hole is shielded. Among them, the plurality of shielding plates move synchronously in the radial direction of the crucible body under the action of the power mechanism.

[0019] In some embodiments of the present utility model, one end of the shielding plate is a plug-in portion, and the other end of the shielding plate is provided with a plug-in groove matching with the plug-in portion. In the first working state, all the shielding plates together form a circular ring having the same inner diameter as the graphite plate. In the second working state, all the shielding plates partially shield the first through hole, and the plug-in portion of one of any two adjacent shielding plates is inserted into the plug-in groove of the other shielding plate. The shielding plate is in a sector ring shape.

[0020] In some embodiments of the present utility model, the power mechanism includes a plurality of power parts having the same number as the shielding plates. Each power part includes:

[0021] A graphite screw rod, the inner end of which passes through the crucible body and is connected to the shielding assembly;

[0022] A rotary motor, which is arranged outside the crucible body and is connected to the outer end of the graphite screw rod.

[0023] In some embodiments of the present utility model, the inner diameter of the graphite plate is 110 - 130 mm.

[0024] In some embodiments of the present utility model, the crucible body includes:

[0025] A lower crucible, which defines a raw material cavity with an open top;

[0026] An upper crucible, which defines a reaction cavity with both an open top and an open bottom, and the upper crucible is arranged on the top of the lower crucible;

[0027] Among them, the gas phase component adjusting assembly is installed on the upper part of the lower crucible.

[0028] In some embodiments of the present utility model, the inner side wall of the top end of the lower crucible is provided with an internal thread, and the outer side wall of the bottom end of the upper crucible is provided with an external thread matching with the internal thread.

[0029] In some embodiments of the present utility model, a clamping groove for clamping the graphite plate is provided on the inner side wall of the crucible body, and a clamping portion matching with the clamping groove is provided at the bottom of the graphite plate.

[0030] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic structural diagram of a silicon carbide crystal growth device with a stable growth rate according to the present utility model;

[0032] Figure 2 is Figure 1 a schematic diagram in the middle and late stages of crystal growth;

[0033] Figure 3 is Figure 2 a top view of the movement of the shielding assembly in the middle;

[0034] Figure 4 is an ideal top view of the movement of the shielding component during the crystal growth stage of the present utility model;

[0035] Figure 5 is a schematic diagram of the initial stage of crystal growth of another embodiment of the present utility model for controlling the gas phase component flow rate of the thermal field;

[0036] Figure 6 is Figure 5 a top view of the shielding assembly at the initial stage of crystal growth;

[0037] Figure 7 is Figure 5 a top view of the movement of the shielding assembly in the middle and late stages of crystal growth;

[0038] Figure 8 is a schematic diagram of the initial stage of crystal growth of yet another embodiment of the present utility model for controlling the gas phase component flow rate of the thermal field;

[0039] Figure 9 is Figure 8 a top view of the first shielding assembly in the middle;

[0040] Figure 10 is Figure 8 a top view of the second shielding assembly in the middle;

[0041] Figure 11 is Figure 8 a top view of the movement of the shielding assembly in the middle and late stages of crystal growth;

[0042] Figure 12 is a schematic diagram of the present utility model without silicon carbide powder loaded.

[0043] Reference numerals:

[0044] Silicon carbide crystal growth apparatus 1000 with a stable growth rate;

[0045] Gas phase component regulating assembly 100;

[0046] Graphite plate 10; First through-hole 11;

[0047] Blocking assembly 20; Baffle plate 21; Second through-hole 2222;

[0048] Power mechanism 30; Power unit 31; Graphite screw 311; Rotating motor 312;

[0049] Crucible body 200; Accommodation cavity 201; Clamping groove 202;

[0050] Lower crucible 210; Raw material cavity 211;

[0051] Upper crucible 220; Reaction cavity 221;

[0052] Crucible cover 300;

[0053] Seed crystal 400;

[0054] Silicon carbide powder 500;

[0055] Heat insulation layer 600;

[0056] Resistance heater 700;

[0057] Furnace body 800. Detailed implementation manners

[0058] The embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present utility model and should not be construed as limiting the present utility model.

[0059] 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 merely 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 may be aware of the applicability of other processes and / or the use of other materials.

[0060] The following will refer to Figures 1 - 12 a silicon carbide crystal growth apparatus 1000 with a stable growth rate according to an embodiment of the present utility model, which includes a gas-phase component adjustment assembly 100, a crucible body 200, and a crucible cover 300. The crucible body 200 defines a receiving cavity 201 that is open at the top; the crucible cover 300 is provided at the top end of the crucible body 200, and a seed crystal 400 is provided at the bottom of the crucible cover 300; the gas-phase component adjustment assembly 100 is provided in the middle of the crucible body 100, and the gas-phase component adjustment assembly 100 is used to adjust the transport channel of the gas-phase components in the crucible body 200 to maintain the growth rate during the entire crystal growth stage. Among them, the gas-phase component adjustment assembly 100 divides the entire receiving cavity 201 into an upper cavity and a lower cavity. The lower cavity is used to store silicon carbide powder 500, and a transport channel flowing from the lower cavity to the upper cavity is defined at the center of the gas-phase component adjustment assembly 100. Heat insulation layers 600 are provided outside the crucible body 200 and the crucible cover 300, and resistance heaters 700 are provided in the heat insulation layers 600 at positions close to the crucible body 200 and facing the upper cavity and the lower cavity; a furnace body 800 is provided outside the heat insulation layers 600, that is, components such as the crucible body 200, the resistance heater 700, and the heat insulation layer 600 are all installed in the furnace body 800.

[0061] Refer to Figures 1 to 12 As shown, silicon carbide powder 500 is loaded into the lower cavity, and the seed crystal 400 is adhered to the center of the bottom of the crucible cover 300. Under the action of the resistance heater 700, the temperature of the crucible body 200 will gradually increase and continue to transfer heat to its interior. Finally, a temperature gradient conducive to crystal growth is formed between the crucible body 200 and the crucible cover 300. At the same time, the internal silicon carbide powder 500 is gradually heated and sublimated to form the gas-phase components required for crystal growth.

[0062] It can be understood that in the early stage of crystal growth, the silicon carbide powder 500 is heated and sublimated, and the formed gas-phase components first enter the upper cavity from the lower cavity through the transport channel defined by the gas-phase component adjustment assembly 100 under the action of the axial temperature gradient, and then continue to move towards the seed crystal 400 on the crucible cover 300, and crystal growth is achieved on the seed crystal 400. At this time, the cross-sectional area of the transport channel defined by the gas-phase component adjustment assembly 100 is in the maximum state. Since the relationship between the flow rate of the gas-phase components and the cross-sectional area of the transport channel defined by the gas-phase component adjustment assembly 100 is inversely proportional, as time goes by, in the middle and late stages of crystal growth, the gas-phase component adjustment assembly 100 is controlled to gradually reduce the cross-sectional area of the transport channel, reduce the channels through which the gas-phase components can flow, so as to maintain the gradually increasing flow gas transmission rate during crystal growth, thereby increasing the diffusion efficiency, making up for the problem of the growth rate reduction caused by temperature attenuation in the later stage of the thermal field, maintaining the stability of the growth rate during the entire crystal growth stage (especially in the middle and late stages), and increasing the effective thickness of the crystal.

[0063] According to the silicon carbide crystal growth device with a stable growth rate of the present utility model, the gas phase component adjustment assembly 100 can be controlled according to the crystal growth stage to achieve the control of the cross-sectional area of the transport channel, maintain the gradually increasing flow gas transmission rate during the crystal growth process, thereby increasing the diffusion efficiency, compensating for the problem of the growth rate reduction caused by the temperature attenuation in the later stage of the thermal field, maintaining the stability of the growth rate throughout the entire crystal growth stage (especially in the middle and later stages), and increasing the effective thickness of the crystal.

[0064] In some embodiments of the present utility model, referring to Figures 1 to 12 As shown, the gas phase component adjustment assembly 100 may include a graphite plate 10, a shielding assembly 20, and a power mechanism 30. The graphite plate 10 is disposed on the inner sidewall of the crucible body 200, and a first through hole 11 penetrating the graphite plate 10 is provided at the center of the graphite plate 10; the shielding assembly 20 is movably disposed on the graphite plate 10, and the shielding assembly 20 defines a second through hole 22, and the shape and size of the second through hole 22 can be changed according to the change in the position of the shielding assembly 20; the power mechanism 30 is connected to the shielding assembly 20 for controlling the shielding assembly 20 to move along the radial direction of the crucible body 200; the shielding assembly 20 and the graphite plate 10 jointly define a transport channel for the gas phase component, and by controlling the position of the shielding assembly 20, the adjustment of the cross-sectional size of the gas phase component transport channel can be achieved. Among them, the first through hole 11 forms a first channel, the second through hole 22 forms a second channel, and the first channel and the second channel jointly form a transport channel for the gas phase component; the position and size of the first channel remain unchanged, and the second channel changes with the movement of the shielding assembly 20.

[0065] For example, the graphite plate 10 can be an annular plate. A clamping groove 202 arranged along its circumferential direction can be provided in the middle of the inner sidewall of the crucible body 200, and a clamping portion cooperating with the clamping groove 202 can be provided on the outer edge of the graphite plate 10. The graphite plate 10 is clamped on the crucible body 200 through the clamping portion. This installation method can ensure that the gas phase component formed by sublimation can only move from the first through hole 11 from the lower cavity to the upper cavity, which is beneficial to the convergence of the gas phase component to the center and beneficial to the growth of the crystal. At the same time, the setting of the clamping groove 202 and the clamping portion can also prevent the graphite plate 10 from moving due to the friction generated when the shielding assembly 20 moves above it. The shielding assembly 20 is arranged closely against the upper surface of the graphite plate 10. Under the action of the power mechanism 30, the structure and position of the shielding assembly 20 can change to form a changing second channel. Under the action of the unchanged first channel and the variable second channel, the transport channel for the gas phase component to move from bottom to top will change, thereby realizing the adjustment of the gas phase component transmission rate and providing support for maintaining a stable crystal growth rate.

[0066] It can be understood that in the early stage of crystal growth, the shielding component 20 is located outside the graphite plate 10, and the second through hole 22 is in the maximum state. The gas-phase components in the lower cavity enter the upper cavity through the first through hole 11 and the second through hole 22, and continue to move and grow in the direction of the seed crystal 400. In the middle and late stages of crystal growth, the power mechanism 30 works to drive the shielding component 20 to move towards the first through hole 11 at the center of the graphite plate 10, gradually partially shielding the first through hole 11, reducing the cross-sectional area of the flow channel for the gas-phase components, increasing the flow rate and diffusion efficiency of the flowing gas, compensating for the problem of reduced growth rate caused by temperature decay in the later stage of the thermal field, maintaining the stability of the growth rate throughout the entire crystal growth stage (especially in the middle and late stages), and increasing the effective thickness of the crystal.

[0067] In some embodiments of the present invention, as shown in Figures 1 to 7 FIG. 5, the shielding component 20 may include a plurality of shielding plates 21 evenly distributed along the inner circumference of the crucible body 200. The shielding plates 21 have at least a first working state and a second working state. In the first working state, the shielding plates 21 are completely moved above the graphite plate 10 so that the first through hole 11 is completely exposed; in the second working state, the shielding plates 21 are moved to the first through hole 11 so that the first through hole 11 is at least partially shielded; wherein, the plurality of shielding plates 21 move synchronously along the radial direction of the crucible body 200 under the action of the power mechanism 30.

[0068] Specifically, the shielding plate 21 may be fan-shaped. The plurality of shielding plates 21 are evenly distributed along the circumferential direction of the graphite plate 10 and are installed closely to the graphite plate 10. The outer sides of the plurality of shielding plates 21 are connected to the power mechanism 30. Under the action of the power mechanism 30, the shielding plates 21 can move along the radial direction of the graphite plate 10 to change their positions, thereby realizing different shielding of the first through hole 11 on the graphite plate 10 and adjusting the cross-sectional area of the gas-phase component transport channel.

[0069] It can be understood that in the initial stage of crystal growth, the plurality of shielding plates 21 are all in the first working state. At this time, the shielding plates 21 are all retracted onto the graphite plate 10 and will not shield the first through hole 11. The gas-phase components in the lower cavity can directly move upward into the upper cavity through the first through hole 11 and grow on the seed crystal 400. In the middle and late stages of crystal growth, the plurality of shielding plates 21 move towards the center simultaneously under the action of the power mechanism 30. The plurality of shielding plates 21 gradually shield the first through hole 11 from the outside, and the cross-sectional area of the gas-phase component transport channel gradually decreases, increasing the flow rate and diffusion efficiency of the flowing gas, compensating for the problem of reduced growth rate caused by temperature decay in the later stage of the thermal field, maintaining the stability of the growth rate throughout the entire crystal growth stage (especially in the middle and late stages), and increasing the effective thickness of the crystal.

[0070] It should be noted that, since multiple baffle plates 21 are evenly distributed in the circumferential direction, under the action of the power mechanism 30, they will synchronously move inward. The cross-sectional area of the second through holes 22 (second channels) formed by the multiple baffle plates 21 approximately decreases geometrically and symmetrically. This ensures that during the crystal growth process, while the gas-phase components stably converge towards the center, the uniformity of the gas-phase components at each position is also ensured as much as possible, which is beneficial to the growth of the crystal.

[0071] In some embodiments of the present invention, referring to Figures 5 to 7 as shown, one end of the baffle plate 21 is a plug-in portion, and the other end of the baffle plate 21 is provided with a plug-in groove that matches the plug-in portion; in the first working state, all the baffle plates 21 together form a circular ring that is the same as the inner diameter of the graphite plate 10; in the second working state, all the baffle plates 21 partially block the first through hole 11, and the plug-in portion of one baffle plate 21 among any two adjacent baffle plates 21 is inserted into the plug-in groove of the other baffle plate 21. Under the action of the power mechanism 30, the baffle plates 21 can be switched between the first working state and the second working state.

[0072] For example, the number of baffle plates 21 is two, and the two baffle plates 21 are installed on the graphite plate 10 in a centrosymmetric manner. The baffle plate 21 is a semi-circular ring structure, and the inner diameter of the baffle plate 21 is equal to the inner diameter of the graphite plate 10 (i.e., the diameter of the first through hole 11). The thicknesses of both ends of the baffle plate 21 are different, the thinner end is the plug-in portion, and the thicker end is provided with a plug-in groove.

[0073] It can be understood that in the initial stage of crystal growth, the two baffle plates 21 are assembled into a circular ring structure, and its inner diameter is the same as that of the graphite plate 10, that is, the two baffle plates 21 are circumferentially arranged around the outside of the first through hole 11 on the graphite plate 10. The second through hole 22 formed by the baffle plates 21 is the same as the first through hole 11, and the gas-phase components are transported upward through the first through hole 11 and the second through hole 22. In the middle and late stages of crystal growth, the power mechanism 30 starts to work, driving the two baffle plates 21 to move synchronously in opposite directions; due to the centrosymmetric arrangement of the two baffle plates 21, the plug-in portion of the left baffle plate 21 will extend into the plug-in groove of the right baffle plate 21, and the plug-in portion of the right baffle plate 21 will also extend into the plug-in groove of the left baffle plate 21, that is, the two ends of the two baffle plates 21 cross corresponding to each other, and the size of the second through hole 22 formed by the two baffle plates 21 gradually decreases, and the cross-sectional area of the transport channel of the gas-phase components jointly formed by the first through hole 11 and the second through hole 22 gradually decreases to increase the flow gas transmission rate, diffusion efficiency, etc.

[0074] Referring to Figure 4As shown in the figure, considering that the cross-sectional area of the gas-phase component transport channel gradually decreases more uniformly in all directions from the periphery (that is, the second through-hole 22 formed by multiple baffle plates 21 is more approximate to a circle), the transportation of gas-phase components is more stable and more conducive to crystal growth. The more baffle plates, the better. However, the more baffle plates, the more complex the structure and the higher the cost. Considering comprehensively, the number of baffle plates is optimally 3 to 5.

[0075] In view of this, in order to make the cross-sectional area of the defined transport channel more approximately geometrically symmetrically decreasing, referring to Figures 8 to 11 As shown in the figure, the shielding assembly 20 can be provided with two groups, and the two groups of shielding assemblies 20 are successively installed on the graphite plate 10. For the convenience of description, let the group of shielding assemblies 20 located below be the first shielding assembly, and the group of shielding assemblies 20 located above be the second shielding assembly. The first shielding assembly is directly installed on the graphite plate 10, and the second shielding assembly is installed above the first shielding assembly. The structures of the first shielding assembly and the second shielding assembly are the same, but the installation angles are different. Assuming that the number of baffle plates in each shielding assembly is N, the included angle between the first shielding assembly and the second shielding assembly is 180 / N degrees, that is, the first shielding assembly rotates 180 / N degrees and then completely coincides with the projection of the second shielding assembly on the graphite plate 10. Taking the number of baffle plates 21 in each shielding assembly 20 as two as an example, the included angle between the first shielding assembly and the second shielding assembly is 90 degrees, that is, the first shielding assembly 20 will completely coincide with the second shielding assembly after rotating 90 degrees. Compared with only setting one layer of shielding assembly, the cross-sectional area of the transport channel defined by the setting of the two-layer shielding assembly structure is more approximately geometrically symmetrically decreasing.

[0076] In some embodiments of the present invention, referring to Figures 1 to 12As shown in the figure, the power mechanism 30 includes a plurality of power units 31 having the same number as the number of shielding plates 21. Each power unit 31 includes: a graphite screw 311 and a rotary motor 312. The inner end of the graphite screw 311 passes through the crucible body 200 and is connected to the shielding assembly 20. The rotary motor 312 is arranged outside the crucible body 200 and is connected to the outer end of the graphite screw 311. Specifically, the graphite screw 311 is rotatably mounted on the side wall of the crucible body 200, and the axial direction of the graphite screw 311 is consistent with the radial direction of the crucible body 200; the inner end of the graphite screw 311 (i.e., the end located inside the crucible body 200, the same below) is provided with a thread, and the end of the graphite screw 311 located outside the crucible body 200 may not be provided with a thread. A slider is provided on the inner end of the graphite screw 311, and the slider is connected to the outer end of the shielding plate 21. Among them, the installation of the slider satisfies that when the graphite screw 311 rotates, the slider can move left and right along the axial direction of the graphite screw 311 to realize the inward and outward movement of the shielding plate 21 along the radial direction of the crucible body 200. The rotary motor 312 is a two-way servo motor, so that the slider can drive the shielding plate 21 to converge stably towards the center at a speed of 0.01 mm / h - 1 mm / h during the crystal growth process.

[0077] It can be understood that when it is necessary to adjust the position of the shielding plate 21, the rotary motor 312 can be started to work. Under the drive of the rotary motor 312, the graphite screw 311 will rotate, and the shielding plate 21 will move along the radial direction of the crucible body 200 under the action of the slider. During the crystal growth process, the slider can be controlled to move away from the direction of the rotary motor 312 over time to realize the movement of the shielding plate 21 towards the center, and push the shielding plate 21 to converge stably towards the center during the crystal growth process, so as to gradually reduce the intermediate channel allowing the gas-phase components formed by the sublimation of silicon carbide powder to be transported. Correspondingly, when the crystal growth is completed, the rotary motor 312 can also be controlled to rotate in the reverse direction to make the shielding plate 21 move towards the direction close to the side wall of the crucible body 200. It should be noted that in order to ensure that the plurality of shielding plates 21 can move synchronously, the rotary motors 312 in the plurality of power units 31 need to work synchronously.

[0078] In some embodiments of the present invention, refer to Figures 1 to 12 As shown in the figure, the inner diameter of the graphite plate 10 is 110 - 130 mm, that is, the diameter of the first through hole 11 is 110 - 130 mm. Since the diameter of a 6-inch crystal is about 150 mm, this structure of the graphite plate 10 also plays a certain role in increasing the flow gas transmission rate and diffusion efficiency at the initial stage of crystal growth, which is beneficial to the growth of the crystal.

[0079] In some embodiments of the present invention, refer to Figures 1 to 12As shown, the crucible body 200 includes a lower crucible 210 and an upper crucible 220. The lower crucible 210 defines a raw material cavity 211 with an open top; the upper crucible 220 defines a reaction cavity 221 with both an open top and an open bottom, and the upper crucible 220 is disposed on the top of the lower crucible 210; the gas-phase component adjustment assembly 100 is installed on the upper part of the lower crucible 210. Specifically, the reaction cavity 221 defined by the upper crucible 220 is the upper cavity, the raw material cavity 211 defined by the lower crucible 210 is the lower cavity, and the gas-phase component adjustment assembly 100 is installed on the top of the lower crucible 210. By controlling the gas-phase component adjustment assembly 100, the cross-sectional area of the transport channel for the gas-phase components entering the upper cavity from the lower cavity can be adjusted.

[0080] It can be understood that the clamping groove 202 can be provided on the lower crucible 210, and the graphite plate 10 is clamped in the clamping groove 202 on the lower crucible 210 through the clamping portion on the outer edge. With this up-and-down structure of the crucible body 200, it is convenient for installation and disassembly, and is also conducive to the construction of the overall temperature gradient.

[0081] In some embodiments of the present invention, referring to Figures 1 to 12 As shown, the inner side wall of the top end of the lower crucible 210 is provided with an internal thread, and the outer side wall of the bottom end of the upper crucible 220 is provided with an external thread that matches the internal thread. Connecting the upper crucible 220 and the lower crucible 210 in this threaded connection manner is not only convenient for installation and disassembly, but also by adjusting different screwing heights, the height of the entire crucible body 200 can be adjusted, which is more conducive to making real-time fine adjustments according to the growth situation of the crystal to ensure obtaining a crystal with the best thickness.

[0082] 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. It is 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 should not be construed as a limitation of the present invention.

[0083] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined.

[0084] In the present utility model, unless otherwise clearly specified or limited, terms such as "installation", "connection", "coupling", "fixing", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; 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.

[0085] In the present utility model, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may mean 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 mean 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 mean 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.

[0086] 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 any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0087] 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 apparatus with a stable growth rate, characterized in that, Comprising: A crucible body which defines a receiving cavity with an open top; A crucible lid which is arranged at the top end of the crucible body, and a seed crystal is provided at the bottom of the crucible lid; A gas-phase component adjusting assembly which is arranged in the middle of the crucible body and is used for adjusting the transport channel of the gas-phase components in the crucible body to maintain the growth rate during the entire crystal growth stage.

2. The silicon carbide crystal growth apparatus with a stable growth rate according to claim 1, characterized in that, The gas-phase component adjusting assembly includes: A graphite plate which is arranged on the inner side wall of the crucible body, and a first through hole penetrating through the graphite plate is provided at the center of the graphite plate; A shielding assembly which is movably arranged on the graphite plate; A power mechanism which is connected to the shielding assembly and is used for controlling the shielding assembly to move along the radial direction of the crucible body; Wherein, the shielding assembly and the graphite plate jointly define a transport channel for the gas-phase components, and by controlling the position of the shielding assembly, the cross-section of the gas-phase component transport channel can be adjusted.

3. The silicon carbide crystal growth device with a stable growth rate according to claim 2, wherein The shielding assembly includes a plurality of shielding plates evenly distributed along the inner circumferential direction of the crucible body. The shielding plates have at least a first working state and a second working state. In the first working state, the shielding plates are completely moved above the graphite plate so that the first through hole is completely exposed; in the second working state, the shielding plates are moved to the first through hole so that at least part of the first through hole is blocked; wherein, the plurality of shielding plates move synchronously along the radial direction of the crucible body under the action of the power mechanism.

4. A silicon carbide crystal growth apparatus having a stable growth rate according to claim 3, characterized in that, One end of the shielding plate is a plugging portion, and a plugging groove matched with the plugging portion is provided at the other end of the shielding plate; in the first working state, all the shielding plates jointly form a circular ring with the same inner diameter as the graphite plate; in the second working state, all the shielding plates partially block the first through hole, and the plugging portion of one of any two adjacent shielding plates is inserted into the plugging groove of the other shielding plate, and the shielding plate is fan-shaped.

5. A silicon carbide crystal growth apparatus having a stable growth rate according to claim 3, characterized in that, The power mechanism includes a plurality of power parts with the same number as the shielding plates. Each power part includes: A graphite screw rod, the inner end of which passes through the crucible body and is connected to the shielding assembly; A rotary motor which is arranged outside the crucible body and is connected to the outer end of the graphite screw rod.

6. The silicon carbide crystal growth apparatus with a stable growth rate according to claim 2, wherein, The inner diameter of the graphite plate is 110 - 130 mm.

7. A silicon carbide crystal growth apparatus having a stable growth rate according to claim 2, characterized in that, The crucible body includes: A lower crucible which defines a raw material cavity with an open top; An upper crucible which defines a reaction cavity with both an open top and an open bottom, and the upper crucible is arranged on the top of the lower crucible; Wherein, the gas-phase component adjusting assembly is installed on the upper part of the lower crucible.

8. A silicon carbide crystal growth apparatus having a stable growth rate according to claim 7, characterized in that, Internal threads are provided on the inner side wall at the top end of the lower crucible, and external threads matched with the internal threads are provided on the outer side wall at the bottom end of the upper crucible.

9. A silicon carbide crystal growth apparatus having a stable growth rate according to claim 2, characterized in that, A clamping groove for clamping the graphite plate is provided on the inner side wall of the crucible body, and a clamping portion matched with the clamping groove is provided at the bottom of the graphite plate.

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