A silicon carbide single crystal growth apparatus and method with reduced energy consumption

Abstract

The present application relates to a kind of silicon carbide single crystal growth device and method for reducing energy consumption, belong to crystal growth technical field.The crucible is included, the charge area in the crucible is provided with heat conduction component, the heat conduction component is constituted by heat conduction plate and several gradually reducing diameter heat conduction cylinder, heat conduction plate is in contact with the inner wall of crucible, several heat conduction cylinder are connected with heat conduction plate, the central axis of several heat conduction cylinder all coincide with the central axis of crucible, the heat conduction plate is opened for material to pass through the through-hole, heat conduction cylinder length gradually shortens according to the direction from outer layer to inner layer, and the top end of all heat conduction cylinder is substantially at the same radial plane of crucible.The present application can effectively reduce single crystal growth energy consumption and the highest temperature in crucible, can significantly prolong the service life of crucible (especially graphite crucible) simultaneously.

Description

Technical Field

[0001] This invention relates to a silicon carbide single crystal growth apparatus and method with reduced energy consumption, belonging to the field of crystal growth technology. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] The main methods for growing silicon carbide single crystals include physical vapor transport (PVT), liquid phase transport, and CVD. Currently, PVT is the most mainstream and commonly used method. In PVT, a silicon carbide substrate (2000~2200℃) serving as the seed crystal is placed on top of a graphite crucible, while silicon carbide powder (2300~2500℃) is spread at the bottom. When the silicon carbide powder decomposes upon heating, the sublimated gaseous components are driven upwards by the temperature gradient inside the crucible to crystallize at the seed crystal. In existing PVT growth systems, a temperature gradient of ~300℃ exists inside the crucible, causing the powder area at the bottom of the graphite crucible to be subjected to an extreme high-temperature load of ~2500℃ for extended periods. Furthermore, the intense reaction between the graphite at the bottom of the crucible and the silicon components in the powder at high temperatures leads to severe wear and tear on the crucible wall, affecting the crucible's lifespan. To improve crucible lifespan, the silicon carbide industry currently widely uses imported isostatic graphite, such as SGL Carbon 6510 from Germany, as the raw material for crucibles. However, imported graphite is expensive, hindering cost reduction. Excessive temperature differences within the crucible during growth also lead to high energy consumption during silicon carbide single crystal growth, which is detrimental to energy conservation and emission reduction. Furthermore, the supersaturation at the growth front of silicon carbide single crystals is closely related to the powder transport efficiency, directly determining the growth rate of the silicon carbide single crystal. The powder transport efficiency, in turn, is related to the axial temperature gradient (▽T) of the growth chamber. g ) and the axial temperature gradient inside the material (▽T) p The degree of matching is directly related to the degree of ▽T. p >▽T g When the component transport within the powder is stronger than that in the growth chamber, gas supersaturation at the raw material interface can trigger secondary crystallization on the powder surface, hindering subsequent component transport. This not only reduces the silicon carbide single crystal growth rate but also decreases the powder utilization rate. p <▽T g At that time, the transport of components within the material was weaker than that within the growth chamber, which limited the improvement of the growth rate of silicon carbide single crystals.

[0004] Chinese patent CN116180221A features an annular material ring with an inner wall opening inside the crucible. Silicon carbide powder is placed through this ring, with the center of the crucible left empty. This allows the powder to be transported under a radial temperature gradient, improving powder utilization efficiency. CN117512772A incorporates a graphite support structure inside the powder. By placing a second seed crystal on this structure, synchronous crystal growth is achieved, replacing the original recrystallization at the powder center with crystal growth, thus improving powder utilization efficiency. CN221320157U includes lifting mechanisms on both the graphite crucible and its lid. The combined lifting of these mechanisms allows for flexible adjustment of the material surface distance, improving powder utilization. CN118461121A incorporates an induction heating component inside the crucible. This component generates heat under the action of an induction coil, thereby increasing the internal temperature of the powder and improving powder utilization. However, these methods suffer from problems such as unavoidable axial crystallization, poor second crystal growth quality, inability to simultaneously improve powder utilization and growth rate, and low internal heating efficiency of the powder, resulting in ineffective improvements in powder utilization and crystal growth rate. CN119553358A incorporates a heat-conducting component within the loading area, using a heat-conducting cylinder at the bottom of the heating chamber and heat-conducting towers and rings within the loading area to conduct heat from the bottom of the crucible to the interior of the powder. However, in induction heating, due to the skin effect of the induced current, most of the heat generated by the graphite crucible is concentrated on the sidewall of the crucible or heating chamber, resulting in a high-temperature zone located on the sidewall. This method's heat-conducting device can only conduct heat from the bottom of the crucible to the interior of the powder, failing to conduct heat from the sidewall. Furthermore, in induction heating, the bottom of the crucible is not the highest temperature within the crucible. Heat transfer from the bottom of the crucible to the powder can easily lead to crystallization at the bottom. Since the highest temperature on the sidewall cannot be reduced, the energy consumption for single crystal growth cannot be reduced, and the lifespan of the graphite crucible cannot be extended. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a silicon carbide single crystal growth apparatus and method with reduced energy consumption. The present invention can effectively reduce the energy consumption of single crystal growth and the maximum temperature in the crucible, while significantly extending the service life of the crucible (especially the graphite crucible).

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, a silicon carbide single crystal growth apparatus with reduced energy consumption includes a crucible. A heat-conducting component is provided in the loading area inside the crucible. The heat-conducting component consists of a heat-conducting plate and several heat-conducting cylinders with gradually decreasing diameters. The heat-conducting plate is in contact with the inner wall of the crucible, and the several heat-conducting cylinders are all connected to the heat-conducting plate. The central axis of the several heat-conducting cylinders coincides with the central axis of the crucible. The heat-conducting plate has through holes for material to pass through. The length of the heat-conducting cylinders gradually shortens from the outer layer to the inner layer, and the tops of all the heat-conducting cylinders are basically located on the same radial surface of the crucible.

[0007] This invention incorporates a heat-conducting component in the crucible. First, this component contacts the inner wall of the crucible via a heat-conducting plate, transferring heat from the crucible's sidewall to the entire component. Then, by connecting the heat-conducting plate and multiple heat-conducting cylinders, the heat conduction path within the powder is controlled, efficiently transferring heat from the crucible's sidewall to the powder. This effectively reduces the crucible's maximum temperature, decreases the temperature gradient in the graphite crucible, reduces energy consumption for single crystal growth, and extends the lifespan of the crucible (especially the graphite crucible).

[0008] The heat-conducting component of the present invention can be an integral structure with the crucible, or it can be a modular separate structure.

[0009] In some implementations, the heat-conducting plate has a conical structure and is located at the bottom of the heat-conducting cylinder. This arrangement helps to further improve the efficiency of heat conduction from the crucible sidewalls to the interior of the powder.

[0010] In some implementations, the innermost heat-conducting cylinder has an inner diameter of 0.1 to 0.4 times the inner diameter of the crucible loading area. This arrangement helps to further reduce the temperature difference within the material and improve powder utilization; at the same time, it helps to increase the single crystal growth rate and extend the crucible life.

[0011] In some implementations, the height of the heat-conducting component is 0.8 to 1.0 times the height of the crucible loading area. This setting helps to further reduce the temperature difference within the material and improve powder utilization; at the same time, it helps to increase the single crystal growth rate and extend the crucible life.

[0012] In some implementations, the thickness of the heat-conducting component is 10-20 mm. This setting helps to further reduce the temperature difference within the material and improve powder utilization; at the same time, it helps to increase the single crystal growth rate and extend the crucible life.

[0013] In some implementations, the distance between adjacent heat-conducting cylinders is 5% to 35% of the crucible diameter. This setting helps to further reduce the temperature difference within the material and improve powder utilization; at the same time, it helps to increase the single crystal growth rate and extend the crucible life.

[0014] In some embodiments, the heat-conducting component is made of high thermal conductivity graphite or high thermal conductivity metal carbide material resistant to high temperatures. More preferably, the high thermal conductivity material has a thermal conductivity of not less than 100 W / (m·K) at room temperature. Specifically, the high thermal conductivity graphite material includes, but is not limited to, isostatically pressed graphite and extruded graphite. Specifically, the high thermal conductivity, high-temperature resistant metal carbide material includes, but is not limited to, tantalum carbide and niobium carbide.

[0015] In some embodiments, the crucible is made of graphite. Specifically, the graphite material of the crucible is isostatically pressed graphite. This invention does not impose strict requirements on the grade of graphite.

[0016] In some embodiments, a crucible heating device is also included, which heats the sidewalls of the crucible. Specifically, the crucible heating device is an induction heater (inductor coil or induction coil) or a resistance heater. When the crucible heating device is an induction coil, an insulation layer is provided between the crucible heating device and the crucible.

[0017] In the silicon carbide single crystal growth apparatus provided by the present invention, the silicon carbide seed crystal is set at the top of the crucible space, and the silicon carbide powder is filled into the loading area in the lower or middle part of the crucible space.

[0018] The heat-conducting component of this invention is made of graphite or high-temperature resistant metal carbide material with a thermal conductivity higher than that of silicon carbide powder. Regarding the specifications of the heat-conducting component, if its inner diameter (i.e., the inner diameter of the innermost heat-conducting cylinder) is too large, it cannot effectively transfer heat from the crucible sidewall to the center of the powder, thus failing to reduce the temperature of the crucible sidewall; if the inner diameter is too small, it will affect the loading and result in insufficient loading, impacting single crystal growth; if its height is too low, heat from the crucible sidewall cannot be effectively transferred to the powder surface, still causing secondary crystallization on the powder surface; if its height is too high, the heat-conducting component will have a guiding effect on the transport of components within the growth cavity, affecting the crystal surface shape; if the spacing between the heat-conducting cylinders is too large, the powder temperature between the cylinders will be low, leading to recrystallization; if the spacing is too small, the loading area will be reduced, resulting in insufficient loading; if its thickness is too thin, the thermal conductivity will be insufficient, still failing to effectively reduce the crucible temperature; if its thickness is too thick, although it enhances the thermal conductivity, it occupies too much space in the loading area, resulting in insufficient loading. Therefore, by setting reasonable inner diameter, height, spacing, and thickness of the heat-conducting components, heat can be efficiently transferred from the crucible sidewall to the center and surface of the powder, effectively reducing the maximum temperature of the crucible and improving the internal temperature uniformity of the powder, thus preventing secondary crystallization. The method described in this invention can effectively reduce the temperature gradient of the growth system, extend the service life of the graphite crucible, and reduce energy consumption during crystal growth.

[0019] Secondly, a method for growing silicon carbide single crystals with reduced energy consumption, providing the aforementioned silicon carbide single crystal growth apparatus, includes the following steps: The silicon carbide powder used as raw material for silicon carbide single crystal growth is evenly spread in the lower or middle-lower part of the loading area inside the crucible, and the silicon carbide powder is submerged in the heat-conducting components. The silicon carbide seed crystal is placed at the top of the space inside the crucible; The silicon carbide single crystal growth apparatus is sealed and subjected to vacuum treatment; The inside of the single crystal growth equipment after vacuum treatment is heated, and carrier gas is introduced to the preset growth pressure to carry out single crystal growth. After the crystal growth is complete, the temperature is lowered and a carrier gas is introduced to the preset cooling pressure. The crystal is then cooled to obtain the desired result.

[0020] In some implementations, the temperature for single crystal growth is 2100–2500 °C. Specifically, the growth time is 60–120 h.

[0021] In some implementations, the growth pressure is 1 to 30 mbar.

[0022] In some implementations, the cooling pressure is 300 to 1000 mbar.

[0023] In some embodiments, the carrier gas may be argon, hydrogen, nitrogen, or a mixture thereof.

[0024] The beneficial effects of this invention are as follows: (1) In this invention, by cleverly setting a heat-conducting component of appropriate size inside the crucible, the heat from the sidewall of the crucible is effectively transferred to the interior and surface of the powder, reducing the maximum temperature of the crucible during single crystal growth, thereby reducing the energy consumption of single crystal growth. In addition, since the maximum temperature of the crucible during single crystal growth is reduced, the operating environment of the crucible (graphite crucible) becomes less harsh, which to some extent reduces the degree of corrosion of the crucible (graphite crucible) by silicon components and improves the service life of the crucible (graphite crucible). Both the reduction in growth energy consumption and the improvement in the service life of the crucible (graphite crucible) are of great significance for reducing the cost of silicon carbide single crystal growth.

[0025] (2) By setting a heat-conducting component inside the crucible, the present invention significantly reduces the operating temperature of the crucible (graphite crucible). Therefore, it can broaden the "material selection window" of the graphite crucible, reduce the requirements for the quality of graphite used to prepare the crucible, not only reduce the cost of graphite materials in silicon carbide single crystal growth, but also increase the proportion of lower quality graphite in the silicon carbide single crystal growth industry chain, and promote the healthy development of the industry chain.

[0026] (3) This invention cleverly transfers the temperature of the crucible sidewall to the powder by setting a heat-conducting component of appropriate size inside the crucible, thereby homogenizing the temperature distribution inside the powder and effectively solving the technical bottleneck of high sidewall temperature and low center temperature in induction heating. It effectively solves the recrystallization phenomenon inside the powder without changing the temperature distribution at the growth front, thus improving the powder utilization rate during single crystal growth. Furthermore, the heat-conducting component allows for flexible adjustment of the axial temperature gradient inside the powder, matching it with the axial temperature gradient within the growth chamber, thereby improving both powder utilization and transport efficiency, and accelerating the crystal growth rate.

[0027] (4) The present invention places the heat-conducting components in the loading area, which will not affect the temperature field of the growth chamber and the growth interface. It is compatible with other current growth processes and is easy to promote and use. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0029] Figure 1 This is a schematic diagram of the silicon carbide single crystal growth apparatus in Embodiment 1 of the present invention.

[0030] Figure 2 This is a three-dimensional schematic diagram of the silicon carbide single crystal growth apparatus in Embodiment 1 of the present invention.

[0031] Figure 3 This is a schematic diagram of the structure of the heat-conducting component in Embodiment 1 of the present invention.

[0032] Figure 4 This is a bottom view of the heat-conducting component in Embodiment 1 of the present invention.

[0033] Figure 5 This is a temperature field diagram inside the graphite crucible for silicon carbide single crystal growth obtained by numerical simulation in Example 2 of this invention.

[0034] Figure 6 This is a temperature field diagram inside the graphite crucible for silicon carbide single crystal growth obtained by numerical simulation in Comparative Example 1 of this invention.

[0035] Among them, 1 is the crucible lid, 2 is the silicon carbide seed crystal, 3 is the grown silicon carbide single crystal, 4 is the graphite crucible, 5 is the heat-conducting component, 6 is the silicon carbide powder, 7 is the heat-conducting plate, and 8 is the heat-conducting cylinder. Detailed Implementation

[0036] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0037] Terminology Explanation: Maximum crucible temperature: In this invention, it refers to the highest temperature of the graphite crucible during single crystal growth. In the PVT method for single crystal growth, the maximum crucible temperature is generally located on the lower sidewall of the crucible.

[0038] Axial temperature gradient within the growth chamber: In this invention, it is represented by ▽Tg, which specifically refers to the temperature difference between the center of the silicon carbide growth interface and the surface of the silicon carbide powder, and the temperature difference per unit length.

[0039] Axial temperature gradient inside the powder: In this invention, it is represented by ▽Tp, which specifically refers to the axial component of the internal temperature difference of the powder, the temperature difference per unit length.

[0040] Secondary crystallization: In this invention, it refers to the phenomenon of crystallization occurring on the surface of powder in a lower temperature region during the growth of silicon carbide single crystals.

[0041] Growth energy consumption: In this invention, this refers to the heating energy consumption required to enter the stable growth stage during the growth of silicon carbide single crystals, which can be expressed as the product of heating frequency and time. It can also be described by heating power within the same time period. Generally, the greater the overall temperature gradient of the growth system, the higher the required growth power. From the perspective of reducing energy consumption, the lower the growth power, the better.

[0042] Crucible weight loss per unit time: In this invention, this refers to the difference between the weight of the graphite crucible after growth and the weight of the graphite crucible before growth per unit time during the silicon carbide single crystal growth process. Because graphite reacts with silicon components and corrodes at high temperatures, and the higher the temperature, the more severe the corrosion. From the perspective of extending the crucible's service life, the smaller the crucible weight loss, the better.

[0043] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0044] Example 1 A silicon carbide single crystal growth device with reduced energy consumption, such as Figures 1-2 As shown, the growth crucible consists of a crucible cover 1, a graphite crucible 4, and a heat-conducting component 5, wherein the heat-conducting component 5 is located in the lower or lower-middle loading area inside the graphite crucible 4. The loading area is used to fill silicon carbide powder 6, and the silicon carbide seed crystal 2 is bonded to the bottom inside the crucible cover 1 to guide the growth of silicon carbide single crystal, thereby forming the grown silicon carbide single crystal 3.

[0045] The heat-conducting component 5 consists of a heat-conducting plate 7 and several heat-conducting cylinders 8 with gradually decreasing diameters, such as... Figure 3 As shown, several heat-conducting cylinders 8 are connected to a heat-conducting plate, and the central axis of several heat-conducting cylinders 8 coincides with the central axis of the graphite crucible 4. The heat-conducting plate 7 has through holes for silicon carbide powder 6 (or silicon carbide vapor) to pass through. The heat-conducting plate 7 is in contact with the inner wall of the graphite crucible 4. The length of the heat-conducting cylinders 8 gradually shortens from the outside to the inside, and the tops of all the heat-conducting cylinders 8 are located on the same radial surface of the graphite crucible 4.

[0046] The heat-conducting component 5 can be an integral part of the crucible or a modular separate structure.

[0047] The heat-conducting plate 7 can be disposed at the top or bottom of the heat-conducting cylinder 8. When the heat-conducting plate 7 is disposed at the bottom of the heat-conducting cylinder, the heat-conducting plate 7 has a conical plate structure. This arrangement is beneficial for further improving the efficiency of heat conduction from the crucible sidewall to the interior of the powder, and also helps to optimize the evaporation path of the silicon carbide powder 6, thereby improving the crystallization effect. Preferably, the through hole for the silicon carbide powder 6 (or silicon carbide vapor) to pass through is located at the center of the conical plate structure, and the diameter of the through hole at the center of the conical plate structure is equal to the inner diameter of the innermost heat-conducting cylinder, such as... Figure 4 As shown.

[0048] Preferably, the innermost heat-conducting cylinder has an inner diameter of 0.1 to 0.4 times the inner diameter of the crucible loading area. This arrangement helps to further reduce the temperature difference within the material and improve powder utilization; at the same time, it helps to increase the single crystal growth rate and extend the crucible life.

[0049] Preferably, the height of the heat-conducting component 5 is 0.8 to 1.0 times the height of the crucible loading area. This setting helps to further reduce the temperature difference within the material and improve the powder utilization rate; at the same time, it helps to increase the single crystal growth rate and extend the crucible life.

[0050] Preferably, the thickness of the heat-conducting component 5 is 10-20 mm. This configuration helps to further reduce the temperature difference within the material and improve the powder utilization rate; at the same time, it helps to increase the single crystal growth rate and extend the crucible life.

[0051] Preferably, in the heat-conducting component 5, the distance between adjacent heat-conducting cylinders (hereinafter referred to as the heat-conducting cylinder interval) is 5% to 35% of the crucible diameter. This setting is beneficial to further reduce the temperature difference within the material and improve the powder utilization rate; at the same time, it is beneficial to improve the single crystal growth rate and increase the crucible life.

[0052] Preferably, the heat-conducting component 5 is made of high thermal conductivity graphite or high thermal conductivity metal carbide material resistant to high temperatures. More preferably, the high thermal conductivity material has a thermal conductivity of not less than 100 W / (m·K) at room temperature. Specifically, the high thermal conductivity graphite material includes, but is not limited to, isostatic graphite and extruded graphite. Specifically, the high thermal conductivity and high temperature-resistant metal carbide material includes, but is not limited to, tantalum carbide and niobium carbide.

[0053] Preferably, the graphite crucible 4 is made of isostatic graphite.

[0054] Taking the thermally conductive component 5 and the graphite crucible 4 as a combined separate structure as an example, the method for growing graphite silicon carbide single crystals includes the following steps: 1. Place the heat-conducting component 5 in the loading area of ​​the graphite crucible 4.

[0055] 2. Spread the silicon carbide powder 6 evenly in the loading area of ​​the graphite crucible 4, ensuring that it does not exceed the heat-conducting component 5.

[0056] 3. Attach the silicon carbide seed crystal 2 to the top of the crucible cover 1.

[0057] 4. Place the graphite crucible 4 into the insulation layer of the energy-saving silicon carbide single crystal growth device, seal it, and perform a vacuum treatment inside.

[0058] 5. Heat the inside of the silicon carbide single crystal growth device after vacuum treatment, and fill the inside of the silicon carbide single crystal growth device with carrier gas to the preset growth pressure. After heating to the set growth temperature, maintain it for a period of time to grow single crystals.

[0059] The growth pressure is 1~30 mbar; the single crystal growth temperature is 2100~2500℃; and the holding time is 60~120 h. The carrier gas can be argon, hydrogen, nitrogen, or a mixture thereof.

[0060] 6. After the crystal growth is completed, the inside of the single crystal growth equipment is cooled down, and carrier gas is introduced into the single crystal growth equipment to the preset cooling pressure, so that the crystal cools down naturally to obtain silicon carbide single crystal.

[0061] The cooling pressure is 300~1000 mbar, and the carrier gas can be argon, hydrogen, nitrogen, or a mixture thereof.

[0062] Methods for detecting energy consumption and crucible lifespan in silicon carbide single crystal growth include: The weight of the graphite crucible before and after growth was measured, and the crucible weight loss per unit time was obtained with reference to the single crystal growth time, in order to evaluate the crucible life during the growth process.

[0063] The growth power during the stable growth process is recorded to assess the energy consumption during growth.

[0064] Example 2 This embodiment is the same as embodiment 1, except that it includes the following steps: (1) Select a crucible made of imported isostatic graphite and place the heat-conducting component inside the graphite crucible. The heat-conducting component is made of isostatic graphite with a thickness of 10 mm. The inner diameter of the innermost heat-conducting cylinder is 0.3 times the inner diameter of the loading area, the outer diameter is the inner diameter of the graphite crucible, the height is 1.0 times the height of the loading area, and the spacing between the heat-conducting cylinders is 25% of the crucible diameter.

[0065] (2) Spread silicon carbide powder, which is used as raw material for silicon carbide single crystal growth, evenly on the bottom of the graphite crucible and above the heat-conducting component. The spreading thickness is 70 mm and the spreading mass is 2000 g. Adhere the silicon carbide seed crystal to the bottom of the crucible cover.

[0066] (3) Place the graphite crucible into the single crystal growth furnace and evacuate it. After reaching the preset growth pressure, heat the graphite crucible to 2100℃ to grow silicon carbide single crystals and maintain it for 70 h. After the growth is completed, cool the inside of the growth furnace to cool the crystal and obtain silicon carbide single crystals.

[0067] (4) The graphite crucible was removed from the growth furnace, and silicon carbide single crystals were obtained. It was found that the powder was entirely in a loose state, with no crystals inside or on the surface of the powder. This indicates that the temperature distribution inside the powder is uniform. The temperature field diagram from the numerical simulation is shown below. Figure 5 As shown.

[0068] (5) The thickness of the silicon carbide single crystal, measured by vernier calipers, was 35.12 mm, and the growth rate of the silicon carbide single crystal was 501.7 μm / h. The crucible weight loss per unit time was 0.76 g / h, the expected crucible lifespan was 50 furnaces, and the heating power during the stable growth process was 17.3 kW. This indicates that the silicon carbide single crystal growth method in this case has low energy consumption, long crucible lifespan, and high single crystal growth efficiency.

[0069] Example 3 This embodiment is the same as embodiment 2, except that it includes the following steps: (1) A crucible made of domestically produced isostatic graphite was selected, and the heat-conducting components were placed inside the graphite crucible. The heat-conducting components were made of isostatic graphite with a thickness of 20 mm. The inner diameter of the innermost heat-conducting cylinder was 0.1 times the inner diameter of the loading area, the outer diameter was the inner diameter of the graphite crucible, the height was 0.8 times the height of the loading area, and the spacing between the heat-conducting cylinders was 35% of the crucible diameter.

[0070] (2) Spread silicon carbide powder, which is used as raw material for silicon carbide single crystal growth, evenly on the bottom of the graphite crucible and above the heat-conducting component. The spreading thickness is 70 mm and the spreading mass is 1900 g. Adhere the silicon carbide seed crystal to the bottom of the crucible cover.

[0071] (3) Place the graphite crucible into the single crystal growth furnace and evacuate it. After reaching the preset growth pressure, heat the graphite crucible to 2100℃ to grow silicon carbide single crystals and maintain it for 70 h. After the growth is completed, cool the inside of the growth furnace to cool the crystal and obtain silicon carbide single crystals.

[0072] (4) The graphite crucible was removed from the growth furnace and silicon carbide single crystals were obtained. It was found that the powder was all in a loose state and there was no crystallization inside or on the surface of the powder. This indicates that the temperature distribution inside the powder is uniform.

[0073] (5) The thickness of the silicon carbide single crystal, measured by vernier calipers, was 33.50 mm, and the growth rate of the silicon carbide single crystal was 478.5 μm / h. The crucible weight loss per unit time was 0.83 g / h, the expected crucible lifespan was 45 furnaces, and the heating power during the stable growth process was 17.6 kW. This indicates that the silicon carbide single crystal growth method in this case has low energy consumption, long crucible lifespan, and high single crystal growth efficiency.

[0074] Example 4 This embodiment is the same as embodiment 2, except that it includes the following steps: (1) Place the heat-conducting component inside the graphite crucible. The heat-conducting component is made of tantalum carbide and has a thickness of 15 mm. The inner diameter of the innermost heat-conducting cylinder is 0.2 times the inner diameter of the loading area, the outer diameter is the inner diameter of the graphite crucible, the height is 0.9 times the height of the loading area, and the spacing between the heat-conducting cylinders is 10% of the crucible diameter.

[0075] (2) Spread silicon carbide powder, which is used as raw material for silicon carbide single crystal growth, evenly on the bottom of the graphite crucible and above the heat-conducting component. The spreading thickness is 70 mm and the spreading mass is 1900 g. Adhere the silicon carbide seed crystal to the bottom of the crucible cover.

[0076] (3) Place the graphite crucible into the single crystal growth furnace and evacuate it. After reaching the preset growth pressure, heat the graphite crucible to 2100℃ to grow silicon carbide single crystals and maintain it for 70 h. After the growth is completed, cool the inside of the growth furnace to cool the crystal and obtain silicon carbide single crystals.

[0077] (4) The graphite crucible was removed from the growth furnace and silicon carbide single crystals were obtained. It was found that the powder was all in a loose state and there was no crystallization inside or on the surface of the powder. This indicates that the temperature distribution inside the powder is uniform.

[0078] (5) The thickness of the silicon carbide single crystal, measured by vernier calipers, was 34.31 mm, and the growth rate of the silicon carbide single crystal was 490.1 μm / h. The crucible weight loss per unit time was 0.73 g / h, the expected crucible lifespan was 55 furnaces, and the heating power during the stable growth process was 17.1 kW. This indicates that the silicon carbide single crystal growth method in this case has low energy consumption, long crucible lifespan, and high single crystal growth efficiency.

[0079] Comparative Example 1 In this comparative example, no thermally conductive components were used for silicon carbide single crystal growth, and the remaining growth conditions were exactly the same as in Example 2.

[0080] After growth, the graphite crucible was removed from the single crystal growth furnace, yielding silicon carbide single crystals. Severe crystallization was observed both inside and on the surface of the silicon carbide powder. This indicates a significant temperature difference within the material. The temperature field diagram from the numerical simulation is shown below. Figure 6 As shown, the powder utilization rate is low. The thickness of the silicon carbide single crystal, measured with vernier calipers, is 14.82 mm, and the growth rate is 211.7 μm / h. The crucible weight loss per unit time is 7.01 g / h, the expected crucible lifespan is 10 furnaces, and the heating power during stable growth is 25.3 kW. This indicates that the silicon carbide single crystal growth method in this study has high energy consumption, short crucible lifespan, and low single crystal growth efficiency.

[0081] Comparative Example 2 In this comparative example, the thickness of the heat-conducting component was changed to 40 mm for silicon carbide single crystal growth, and the remaining growth conditions were exactly the same as in Example 2.

[0082] After growth, the graphite crucible was removed from the single crystal growth furnace, yielding silicon carbide single crystals. It was found that although the silicon carbide powder was entirely in a loose state, with no crystals inside or on the surface, the remaining powder was small, and the crystal surface showed severe decomposition and carbonization. This indicates that although the temperature distribution within the material was uniform, the charge was insufficient. The thickness of the silicon carbide single crystal, measured with calipers, was 19.81 mm, and the growth rate was 283 μm / h. The crucible weight loss per unit time was 0.79 g / h, the expected crucible lifespan was 50 furnaces, and the heating power during stable growth was 17.5 kW. This demonstrates that while this embodiment exhibits low energy consumption, long crucible lifespan, and high single crystal growth efficiency, it suffers from insufficient charge, hindering long-term growth.

[0083] Comparative Example 3 In this comparative example, the inner diameter of the innermost heat-conducting cylinder was set to 0.5 times the inner diameter of the loading area for silicon carbide single crystal growth, and the remaining growth conditions were exactly the same as in Example 2.

[0084] After growth, the graphite crucible was removed from the single crystal growth furnace, yielding silicon carbide single crystals. Severe crystallization was observed both inside and on the surface of the silicon carbide powder, indicating significant temperature variations within the material and low powder utilization. The thickness of the silicon carbide single crystal, measured with calipers, was 18.47 mm, and the growth rate was 263.9 μm / h. The crucible weight loss per unit time was 5.90 g / h, the expected crucible lifespan was 10 furnaces, and the heating power during stable growth was 24.8 kW. This indicates that the silicon carbide single crystal growth method described herein has high energy consumption, short crucible lifespan, and low single crystal growth efficiency.

[0085] Comparative Example 4 In this comparative example, the height of the heat-conducting component was changed to 0.5 times the height of the loading area for silicon carbide single crystal growth, and the remaining growth conditions were exactly the same as in Example 2.

[0086] After growth, the graphite crucible was removed from the single crystal growth furnace, yielding silicon carbide single crystals. Severe crystallization was observed both inside and on the surface of the silicon carbide powder, indicating significant temperature variations within the material and low powder utilization. The thickness of the silicon carbide single crystal, measured with calipers, was 19.29 mm, and the growth rate was 275.5 μm / h. The crucible weight loss per unit time was 5.66 g / h, the expected crucible lifespan was 10 furnaces, and the heating power during stable growth was 24.4 kW. This indicates that the proposed method for silicon carbide single crystal growth suffers from high energy consumption, short crucible lifespan, and low single crystal growth efficiency.

[0087] Comparative Example 5 In this comparative example, the spacing between the heat-conducting cylinders of the heat-conducting components was changed to 50% of the crucible diameter, and silicon carbide single crystal growth was carried out in the heat-conducting cylinders. The remaining growth conditions were exactly the same as in Example 2.

[0088] After growth, the graphite crucible was removed from the single crystal growth furnace, yielding a silicon carbide single crystal. Severe crystallization was observed both inside and on the surface of the silicon carbide powder. The thickness of the silicon carbide single crystal, measured with vernier calipers, was 17.46 mm, and the growth rate was 249.4 μm / h. The crucible weight loss per unit time was 6.11 g / h, the expected crucible lifespan was 10 furnaces, and the heating power during stable growth was 24.9 kW. This indicates that the silicon carbide single crystal growth method described herein has high energy consumption, short crucible lifespan, and low single crystal growth efficiency.

[0089] Comparative Example 6 In this comparative example, the thickness of the heat-conducting component was changed to a 3 mm heat-conducting cylinder for silicon carbide single crystal growth, and the remaining growth conditions were exactly the same as in Example 2.

[0090] After growth, the graphite crucible was removed from the single crystal growth furnace, yielding silicon carbide single crystals. Severe crystallization was observed both inside and on the surface of the silicon carbide powder, indicating significant temperature variations within the material and low powder utilization. The thickness of the silicon carbide single crystal, measured with calipers, was 21.11 mm, and the growth rate was 301.6 μm / h. The crucible weight loss per unit time was 5.10 g / h, the expected crucible lifespan was 15 furnaces, and the heating power during stable growth was 23.7 kW. This indicates that the silicon carbide single crystal growth method described herein has high energy consumption, short crucible lifespan, and low single crystal growth efficiency.

[0091] Table 1. Growth rate, crucible weight loss, expected crucible life, and heating power results between different embodiments and comparative examples.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A silicon carbide single crystal growth apparatus with reduced energy consumption, characterized in that, The device includes a crucible, and a heat-conducting component is provided in the loading area of ​​the crucible. The heat-conducting component consists of a heat-conducting plate and several heat-conducting cylinders with gradually decreasing diameters. The heat-conducting plate is in contact with the inner wall of the crucible, and the heat-conducting cylinders are all connected to the heat-conducting plate. The central axis of the heat-conducting cylinders coincides with the central axis of the crucible. The heat-conducting plate has through holes for material to pass through. The length of the heat-conducting cylinders gradually decreases from the outer layer to the inner layer, and the tops of all the heat-conducting cylinders are located on the same radial plane of the crucible. The inner diameter of the innermost heat-conducting cylinder is 0.1 to 0.4 times the inner diameter of the loading area of ​​the crucible. The heat-conducting plate has a conical structure and is located at the bottom of the heat-conducting cylinders. The through holes are located at the center of the conical plate structure, and the diameter of the through hole at the center of the conical plate structure is equal to the inner diameter of the innermost heat-conducting cylinder. The height of the heat-conducting component is 0.8 to 1.0 times the height of the crucible loading area; the thickness of the heat-conducting component is 10 to 20 mm; and the distance between adjacent heat-conducting cylinders is 5% to 35% of the crucible diameter.

2. The silicon carbide single crystal growth apparatus as described in claim 1, characterized in that, The heat-conducting component is made of high thermal conductivity graphite or high thermal conductivity metal carbide material that is resistant to high temperatures, wherein the high thermal conductivity is not less than 100 W / (m·K) at room temperature. Alternatively, the crucible may be made of graphite; or the graphite material of the crucible may be isostatic graphite.

3. The silicon carbide single crystal growth apparatus as described in claim 1, characterized in that, It also includes a crucible heating device that heats the sidewalls of the crucible.

4. A method for growing silicon carbide single crystals with reduced energy consumption, characterized in that, The silicon carbide single crystal growth apparatus according to any one of claims 1 to 3 is provided, comprising the following steps: The silicon carbide powder used as raw material for silicon carbide single crystal growth is evenly spread in the lower or middle-lower part of the loading area inside the crucible, and the silicon carbide powder is submerged in the heat-conducting components. The silicon carbide seed crystal is placed at the bottom of the crucible lid; The silicon carbide single crystal growth apparatus is sealed and subjected to vacuum treatment; The inside of the single crystal growth equipment after vacuum treatment is heated, and carrier gas is introduced to the preset growth pressure to carry out single crystal growth. After the crystal growth is complete, the temperature is lowered and a carrier gas is introduced to the preset cooling pressure. The crystal is then cooled to obtain the desired result.

5. The silicon carbide single crystal growth method as described in claim 4, characterized in that, The temperature for single crystal growth is 2100~2500℃; Alternatively, the growth pressure is 1~30 mbar; Alternatively, the cooling pressure can be 300~1000 mbar; Alternatively, the carrier gas may be argon, hydrogen, nitrogen, or a mixture thereof.

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