Device and method for preparing silicon carbide crystals by HTCVD (high temperature chemical vapor deposition) method

Abstract

The invention provides a device and a method for preparing silicon carbide crystals by an HTCVD (High Temperature Chemical Vapor Deposition) method, the device comprises a crucible as well as a first chamber and a second chamber which are arranged in the crucible and are sequentially connected along the flowing direction of a gas source, and the first chamber and the second chamber are connected through a gas pipeline; the first cavity is sequentially provided with a first gas source pipeline and a first silicon carbide growth area in the gas source flowing direction; and the second cavity is sequentially provided with a second gas source pipeline and a second silicon carbide growth area along the gas source flowing direction. The device and the method can simultaneously grow single crystal silicon carbide and polycrystal silicon carbide, increase the gas utilization rate, reduce the production cost, and prevent the exhaust pipeline from being blocked by tail gas.

Description

Technical Field

[0001] The present invention belongs to the field of silicon carbide crystal preparation, and relates to a device and a method for preparing silicon carbide crystals by the HTCVD method. Background Art

[0002] SiC crystal growth methods include physical vapor transport (PVT). Since there is no liquid-phase SiC with a Si:C stoichiometric ratio of 1:1 under normal pressure, the melt raw material method commonly used in silicon crystal growth is not applicable to the growth of bulk SiC crystals. Instead, the sublimation method has become the main choice. In the sublimation method, SiC powder and a SiC substrate (as a seed crystal) are placed in a graphite crucible, and the temperature on the SiC powder side is slightly higher by setting a temperature gradient. The overall temperature is maintained in the range of 2000 - 2500 °C. This method is now called the modified Lely method and is widely used in the production of SiC substrates. The SiC crystal growth process of the modified Lely method is as Figure 1 shown. Inside the graphite crucible heated to above 2000 °C, the SiC powder sublimates into molecular states such as Si2C, SiC2, and Si, and is transported to the surface of the seed crystal. These atomic molecules move on the surface of the seed crystal and are guided to suitable crystal formation positions, thereby growing bulk SiC single crystals.

[0003] Although the sublimation method has a place in the preparation of SiC single crystals, its growth rate is still slow compared to the Si single crystal growth method using melt raw materials. Although the quality is gradually improving, there are inevitably challenges such as dislocations in the crystals. The HTCVD method shows many advantages in the growth of bulk SiC crystals. First, the high purity of its raw material gas enables precise control of the C / Si ratio in the gas phase, and this key growth parameter has a significant impact on the defect density. Second, this method can achieve the growth of SiC at a relatively fast speed, and the growth rate can reach more than 1 mm / h. However, the HTCVD method also faces some challenges. A large amount of substances generated during the reaction are easily attached to the inside of the growth furnace and the exhaust pipe, making equipment maintenance difficult. At the same time, gas-phase reactions in the gas may generate particles, and these particles may be incorporated into the crystal as impurities, affecting its quality.

[0004] The precursor gases for the high-temperature chemical vapor deposition (HTCVD) method are generally silane (SiH4) and hydrocarbons, such as C2H4 and C3H8. The reaction temperature of HTCVD is generally 2100 - 2300 °C. In the heating zone, the gas will react to form Si and SiC, and these reaction-generated gases are the raw materials for the growth of SiC ingots. The temperature in the gas reaction zone is higher than that at the seed crystal. The temperature gradient ensures mass transfer, and the lower temperature causes the gas phase to solidify on the seed crystal. The growth pressure and growth rate of typical SiC crystals are 250 - 300 mbar and 0.3 - 1.5 mm·h -1 . The main advantages of HTCVD compared to the PVT method are that the prepared SiC has high purity, the ratio of Si / C atoms can be controlled, and the supply of growth raw materials is continuous.

[0005] In the prior art, only one silicon carbide crystal can be grown in one crucible using this technology. The growth temperature of single-crystal SiC is 2100 - 2300 °C, while the growth temperature of polycrystalline SiC is 1200 - 1400 °C. How to grow single-crystal SiC and polycrystalline SiC simultaneously is an urgent problem to be solved. Summary of the Invention

[0006] To solve the technical problems existing in the prior art, the present invention provides a device and method for preparing silicon carbide crystals by the HTCVD method. This device and method can grow single-crystal silicon carbide and polycrystalline silicon carbide simultaneously, increase gas utilization rate, reduce production costs, and avoid the blockage of the exhaust pipe by tail gas.

[0007] To achieve the above technical effects, the present invention adopts the following technical solutions:

[0008] One of the purposes of the present invention is to provide a device for preparing silicon carbide crystals by the HTCVD method. The device includes a crucible and a first chamber and a second chamber disposed inside the crucible and connected in sequence along the gas source flow direction. The first chamber and the second chamber are connected by a gas pipeline;

[0009] The first cavity is sequentially provided with a first gas source pipeline and a first silicon carbide growth area along the gas source flow direction;

[0010] The second cavity is sequentially provided with a second gas source pipeline and a second silicon carbide growth area along the gas source flow direction.

[0011] As a preferred technical solution of the present invention, the first gas source pipeline includes a silicon source pipeline and a carbon source pipeline disposed around the silicon source pipeline.

[0012] As a preferred technical solution of the present invention, a first seed crystal is disposed in the first silicon carbide growth area, and the first seed crystal is connected to the top of the first cavity through a first seed crystal support assembly.

[0013] As a preferred technical solution of the present invention, the first seed crystal is a silicon carbide seed crystal.

[0014] As a preferred technical solution of the present invention, a gas source inlet is provided at the bottom of the first cavity.

[0015] As a preferred technical solution of the present invention, a second seed crystal is provided in the second silicon carbide growth region, and the second seed crystal is connected to the top of the second cavity through a second seed crystal support assembly.

[0016] As a preferred technical solution of the present invention, the second seed crystal is a single crystal silicon seed crystal.

[0017] A second object of the present invention is to provide a method for preparing silicon carbide crystals by the HTCVD method. This method uses the device for preparing silicon carbide crystals by the HTCVD method provided in the first object. This method includes:

[0018] Independently heating the first silicon carbide growth region and the second silicon carbide growth region to the silicon carbide growth temperature respectively;

[0019] Introducing a carrier gas, a silicon source gas, and a carbon source gas. The carrier gas, the silicon source gas, and the carbon source gas reach the first silicon carbide growth region through the first gas source pipeline for single crystal silicon carbide growth;

[0020] The unreacted silicon source gas and carbon source gas enter the second cavity through the gas pipeline, reach the second silicon carbide growth region through the second gas source pipeline, and perform polycrystalline silicon carbide growth.

[0021] As a preferred technical solution of the present invention, the flow rate of the carrier gas is 35-50 slm, the flow rate of the silicon source gas is 200-450 sccm, and the flow rate of the carbon source gas is 80-150 sccm.

[0022] As a preferred technical solution of the present invention, the growth temperature of single crystal silicon carbide is 2100-2300 °C, and the growth pressure is 200-300 mbar;

[0023] The growth temperature of polycrystalline silicon carbide is 1200-1400 °C, and the growth pressure is 200-300 mbar.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] The present invention provides a device and a method for preparing silicon carbide crystals by the HTCVD method. This device and method can grow single crystal silicon carbide and polycrystalline silicon carbide simultaneously, increase gas utilization rate, reduce production costs, and avoid blockage of the exhaust pipeline by tail gas. Description of the Drawings

[0026] Figure 1Schematic structural diagram of the device for preparing silicon carbide crystals by HTCVD method provided by the present invention.

[0027] Figure 2 Schematic structural diagram of the device for preparing silicon carbide crystals by HTCVD method provided in Comparative Example 1 of the present invention.

[0028] Figure 3 Raman spectrum of the 4H-SiC crystal prepared in Example 2 of the present invention.

[0029] Figure 4 Raman spectrum of the 3C-SiC crystal prepared in Example 2 of the present invention.

[0030] In the figure: 26 - upper cover of the reaction chamber, 28 - lower bottom plate of the reaction chamber, 30 - middle pipe wall, 32 - outer pipe wall, 34 - inner pipe wall, 36 - carbon source pipeline, 38 - silicon source pipeline, 40 - spacer ring, 42 - reaction area, 44 - seed crystal, 46 - seed crystal support assembly, 48 - graphite rod, 50 - silicon carbide ingot, 52 - carbon source inlet, 54 - silicon source inlet, 8 - graphite crucible.

[0031] The present invention will be further described in detail below. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the protection of the present invention. The scope of protection of the present invention is subject to the claims. Specific Embodiments

[0032] The technical solution of the present application will be further described below through specific embodiments.

[0033] The specific embodiment of the present invention provides a device for preparing silicon carbide crystals by HTCVD method. The device includes a crucible and a first chamber and a second chamber which are arranged inside the crucible and are connected in sequence along the gas source flow direction. The first chamber and the second chamber are connected through a gas pipeline;

[0034] A first gas source pipeline and a first silicon carbide growth area are sequentially arranged in the first chamber along the gas source flow direction;

[0035] A second gas source pipeline and a second silicon carbide growth area are sequentially arranged in the second chamber along the gas source flow direction.

[0036] In the present invention, a relatively high temperature is set in the first chamber. After the gas source decomposes and reacts at the relatively high temperature, single-crystal silicon carbide is grown in the first silicon carbide growth region. The unreacted gas source enters the second chamber through a gas pipeline. A relatively low temperature is set in the first chamber, and the unreacted gas source serves as the growth gas source for the second chamber, and polycrystalline silicon carbide is grown in the second silicon carbide growth region. This invention of the device realizes the growth of single-crystal silicon carbide and polycrystalline silicon carbide in the same crucible, improves the utilization rate of the gas source at the same time, reduces the content of the gas source in the tail gas, and avoids the blockage of the exhaust pipeline.

[0037] In a specific embodiment of the present invention, the crucible in the device for preparing silicon carbide crystals by the HTCVD method is a crucible commonly used in the field of silicon carbide preparation, such as a graphite crucible, and its specific material and size can be adjusted according to production requirements and scale, and will not be further limited here.

[0038] In a specific embodiment of the present invention, an induction coil is arranged outside the crucible, and the crucible is heated by using the principle of electromagnetic coupling.

[0039] In a specific embodiment of the present invention, the first gas source pipeline includes a silicon source pipeline and a carbon source pipeline arranged around the silicon source pipeline. That is, the silicon source pipeline and the carbon source pipeline are concentric cylindrical cavities, the silicon source pipeline is in the inner layer, and the carbon source pipeline is in the outer layer.

[0040] In a specific embodiment of the present invention, a first seed crystal is arranged in the first silicon carbide growth region, and the first seed crystal is connected to the top of the first chamber through a first seed crystal support assembly.

[0041] In a specific embodiment of the present invention, the growth surface of the first seed crystal faces the gas source flow direction, the back of the first seed crystal is fixed to the first seed crystal support assembly, the first seed crystal support assembly is fixed to the top of the first chamber, and the first seed crystal support assembly is also connected to a first graphite rod.

[0042] In a specific embodiment of the present invention, a gas source reaction region is arranged between the first gas source pipeline and the first silicon carbide growth region.

[0043] In a specific embodiment of the present invention, the first seed crystal is a silicon carbide seed crystal.

[0044] In a specific embodiment of the present invention, a gas source inlet is arranged at the bottom of the first chamber.

[0045] In a specific embodiment of the present invention, a silicon source inlet corresponding to the silicon source pipeline and a carbon source inlet corresponding to the position of the carbon source pipeline are arranged at the bottom of the first chamber.

[0046] In a specific embodiment of the present invention, a second seed crystal is arranged in the second silicon carbide growth region, and the second seed crystal is connected to the top of the second chamber through a second seed crystal support assembly.

[0047] In a specific embodiment of the present invention, the growth surface of the second seed crystal faces the gas source flow direction, the back surface of the second seed crystal is fixed to the second seed crystal support assembly, the second seed crystal support assembly is fixed to the top of the second cavity, and the second seed crystal support assembly is also connected to the second graphite rod.

[0048] In a specific embodiment of the present invention, a gas source reaction area is provided between the second gas source pipeline and the second silicon carbide growth area.

[0049] In a specific embodiment of the present invention, the second seed crystal is a single crystal silicon seed crystal.

[0050] In a specific embodiment of the present invention, an exhaust pipeline is provided at the top of the second cavity for discharging the carrier gas and the unreacted origin from the crucible.

[0051] A specific embodiment of the present invention provides a method for preparing silicon carbide crystals by the HTCVD method. This method uses the device for preparing silicon carbide crystals by the HTCVD method described above, and this method includes:

[0052] Independently heating the first silicon carbide growth area and the second silicon carbide growth area to the silicon carbide growth temperature respectively;

[0053] Introducing a carrier gas, a silicon source gas, and a carbon source gas. The carrier gas, the silicon source gas, and the carbon source gas reach the first silicon carbide growth area through the first gas source pipeline for single crystal silicon carbide growth;

[0054] The unreacted silicon source gas and carbon source gas enter the second cavity through the gas pipeline, reach the second silicon carbide growth area through the second gas source pipeline, and perform polycrystalline silicon carbide growth.

[0055] In a specific embodiment of the present invention, before heating the first silicon carbide growth area and the second silicon carbide growth area, the inside of the crucible is evacuated.

[0056] In a specific embodiment of the present invention, the carrier gas, the silicon source gas, and the carbon source gas are all gases commonly used in the field of silicon carbide preparation, and no further limitation is made here.

[0057] In a specific embodiment of the present invention, the carrier gas is preferably hydrogen.

[0058] In a specific embodiment of the present invention, the silicon source gas is preferably silane and / or monochlorosilane.

[0059] In a specific embodiment of the present invention, the carbon source gas is preferably ethylene and / or propane.

[0060] In a specific embodiment of the present invention, the flow rate of the carrier gas is 35-50 slm, such as 35 slm, 36 slm, 38 slm, 40 slm, 42 slm, 45 slm, 48 slm or 50 slm, etc.; the flow rate of the silicon source gas is 200-450 sccm, such as 200 sccm, 220 sccm, 250 sccm, 280 sccm, 300 sccm, 320 sccm, 350 sccm, 380 sccm, 400 sccm, 420 sccm or 450 sccm, etc.; the flow rate of the carbon source gas is 80-150 sccm, such as 80 sccm, 90 sccm, 100 sccm, 110 sccm, 120 sccm, 130 sccm, 140 sccm or 150 sccm, etc. However, it is not limited to the listed data, and other unlisted values within the above numerical ranges are equally applicable.

[0061] In a specific embodiment of the present invention, the carrier gas is introduced into the first cavity through the silicon source inlet and the carbon source inlet, and the carrier gas carries the silicon source gas and the carbon source gas and transports them towards the first seed crystal and the second seed crystal.

[0062] In a specific embodiment of the present invention, the growth temperature of single crystal silicon carbide is 2100-2300 °C, and the growth pressure is 200-300 mbar.

[0063] In a specific embodiment of the present invention, the growth temperature of polycrystalline silicon carbide is 1200-1400 °C, and the growth pressure is 200-300 mbar.

[0064] In a specific embodiment of the present invention, the total growth time of single crystal silicon carbide and polycrystalline silicon carbide is 10-15 h, such as 10 h, 11 h, 12 h, 13 h, 14 h or 15 h, etc. However, it is not limited to the listed data, and other unlisted values within this numerical range are equally applicable.

[0065] In a specific embodiment of the present invention, after the growth is completed, the temperature is decreased, the furnace is stopped, and the single crystal silicon carbide and polycrystalline silicon carbide are taken out according to the furnace shutdown procedure. The furnace shutdown procedure is the conventional cooling procedure after growing silicon carbide by HTCVD, and will not be specifically described herein.

[0066] In a specific embodiment of the present invention, the single crystal silicon carbide refers to a 4H-SiC crystal, and the polycrystalline silicon carbide refers to a 3C-SiC crystal.

[0067] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, the typical but non-limiting embodiments of the present invention are as follows:

[0068] Example 1

[0069] This example provides a device for preparing silicon carbide crystals by the HTCVD method, and its structure is asFigure 1 As shown, the device includes a graphite crucible 8 and a first chamber and a second chamber disposed inside the crucible;

[0070] In the first chamber, a first gas source pipeline and a first silicon carbide growth region are sequentially arranged along the gas source flow direction. The first gas source pipeline includes a silicon source pipeline 38 and a carbon source pipeline 36 disposed around the silicon source pipeline. That is, the space surrounded by the inner pipe wall 34 is the silicon source pipeline 38, and the space between the inner pipe wall 34 and the outer pipe wall 32 is the silicon source pipeline 38. A silicon source inlet 54 is provided at the bottom of the first chamber corresponding to the silicon source pipeline 38, and a carbon source inlet 52 is provided corresponding to the carbon source pipeline 36. A seed crystal 44 is provided in the first silicon carbide growth region. The seed crystal 44 is connected to the top of the first chamber through a seed crystal support assembly 46, and the first seed crystal support assembly 46 is connected to a graphite rod 48. A spacer ring 40 is provided between the first gas source pipeline and the first silicon carbide growth region, and the inner region of the spacer ring is a gas source reaction region;

[0071] In the second chamber, a second gas source pipeline and a second silicon carbide growth region are sequentially arranged along the gas source flow direction. The second gas source pipeline is the silicon source pipeline 38. The outer wall of the gas source optical path 38 is the outer pipe wall 32. A seed crystal 44 is provided in the second silicon carbide growth region. The seed crystal 44 is connected to the top of the second chamber through a seed crystal support assembly 46, and the seed crystal support assembly 46 is connected to a graphite rod 48. A spacer ring 40 is provided between the second gas source pipeline and the second silicon carbide growth region, and the inner region of the spacer ring is a gas source reaction region 42. An exhaust pipe is provided at the top of the second chamber.

[0072] Embodiment 2

[0073] This embodiment provides a method for preparing silicon carbide crystals by the HTCVD method. This method uses the device for preparing silicon carbide crystals by the HTCVD method provided in Embodiment 1. This method includes:

[0074] Vacuum the first silicon carbide growth region and the second silicon carbide growth region to 3 mbar;

[0075] Heat the first silicon carbide growth region to 2200 °C and the second silicon carbide growth region to 1300 °C;

[0076] Introduce carrier gas H2 through the silicon source inlet 54 and the carbon source inlet 52, with a flow rate of 45 slm; introduce silicon source gas silane through the silicon source inlet 54, with a flow rate of 300 sccm; introduce carbon source gas ethylene through the carbon source inlet 52, with a flow rate of 120 sccm; the carrier gas H2 carries the silicon source gas silane and the silicon source gas silane, and respectively reaches the reaction region through the silicon source pipeline 38 and the carbon source pipeline 36 to generate Si and SiC, and then is sent to the first silicon carbide growth region by the carrier gas, and 4H-silicon carbide crystals are grown on the seed crystal 44 (silicon carbide seed crystal), and the growth pressure is 250 mbar;

[0077] The unreacted silicon source gas and carbon source gas enter the second cavity through the gas pipeline, reach the reaction area 42 through the second gas source pipeline, and are then sent to the second silicon carbide growth area by the carrier gas, where 3C-silicon carbide crystals grow on the seed crystal 44 (single crystal silicon seed crystal), and the growth pressure is 250 mbar.

[0078] Example 3

[0079] This example provides a method for preparing silicon carbide crystals by the HTCVD method. This method uses the device for preparing silicon carbide crystals by the HTCVD method provided in Example 1, and this method includes:

[0080] The first silicon carbide growth area and the second silicon carbide growth area are evacuated to 3 mbar.

[0081] The first silicon carbide growth area is heated to 2100 °C and the second silicon carbide growth area is heated to 1200 °C.

[0082] Carrier gas H2 is introduced through the silicon source inlet 54 and the carbon source inlet 52 at a flow rate of 35 slm; silane, the silicon source gas, is introduced through the silicon source inlet 54 at a flow rate of 200 sccm; ethylene, the carbon source gas, is introduced through the carbon source inlet 52 at a flow rate of 80 sccm; the carrier gas H2 carries the silane, the silicon source gas, and the silane, the silicon source gas, which reach the reaction area through the silicon source pipeline 38 and the carbon source pipeline 36 respectively to generate Si and SiC, and are then sent to the first silicon carbide growth area by the carrier gas, where 4H-silicon carbide crystals grow on the seed crystal 44 (silicon carbide seed crystal), and the growth pressure is 200 mbar.

[0083] The unreacted silicon source gas and carbon source gas enter the second cavity through the gas pipeline, reach the reaction area 42 through the second gas source pipeline, and are then sent to the second silicon carbide growth area by the carrier gas, where 3C-silicon carbide crystals grow on the seed crystal 44 (single crystal silicon seed crystal), and the growth pressure is 200 mbar.

[0084] Example 4

[0085] This example provides a method for preparing silicon carbide crystals by the HTCVD method. This method uses the device for preparing silicon carbide crystals by the HTCVD method provided in Example 1, and this method includes:

[0086] The first silicon carbide growth area and the second silicon carbide growth area are evacuated to 3 mbar.

[0087] The first silicon carbide growth area is heated to 2300 °C and the second silicon carbide growth area is heated to 1400 °C.

[0088] Carrier gas H2 is introduced through the silicon source inlet 54 and the carbon source inlet 52, with a flow rate of 50 slm; silane, the silicon source gas, is introduced through the silicon source inlet 54, with a flow rate of 450 sccm; ethylene, the carbon source gas, is introduced through the carbon source inlet 52, with a flow rate of 150 sccm; the carrier gas H2 carries the silicon source gas silane and the silicon source gas silane, and they reach the reaction zone through the silicon source pipeline 38 and the carbon source pipeline 36 respectively to generate Si and SiC, and then are sent by the carrier gas to the first silicon carbide growth zone to grow 4H-silicon carbide crystals on the seed crystal 44 (silicon carbide seed crystal), and the growth pressure is 300 mbar;

[0089] The unreacted silicon source gas and carbon source gas enter the second cavity through the gas pipeline, reach the reaction zone 42 through the second gas source pipeline, and then are sent by the carrier gas to the second silicon carbide growth zone to grow 3C-silicon carbide crystals on the seed crystal 44 (single crystal silicon seed crystal), and the growth pressure is 300 mbar.

[0090] Example 5

[0091] In this example, except that the silicon source gas is monochlorosilane and the carbon source gas is propane, the other conditions are the same as those in Example 1.

[0092] Comparative Example 1

[0093] This comparative example provides a device for preparing silicon carbide crystals by the HTCVD method. The structure of the device is as Figure 2 shown. The device includes a quartz tube and a graphite crucible arranged inside the quartz tube. A gas inlet is arranged at the bottom of the graphite crucible for inputting carrier gas, silicon source gas and carbon source gas. A seed crystal is arranged at the top of the graphite crucible. The seed crystal is connected to the top of the graphite crucible through a seed crystal support assembly. The seed crystal support assembly is connected to a graphite rod. An exhaust pipe is also arranged at the top of the graphite crucible, and the exhaust pipe is arranged on both sides of the seed crystal support assembly.

[0094] Using this device to grow 4H-silicon carbide crystals, the growth conditions and the carrier gas, silicon source gas and carbon source gas used are the same as those in Example 2.

[0095] Comparative Example 2

[0096] Using the device provided in Comparative Example 1 to grow 3C-silicon carbide crystals, the growth conditions and the carrier gas, silicon source gas and carbon source gas used are the same as those in Example 2.

[0097] The 4H-SiC crystals and 3C-SiC crystals prepared in Examples 1-5 and Comparative Examples 1 and 2 are tested for crystal form using Raman spectroscopy, and whether there is material deposition inside the exhaust pipe is observed after the growth of the silicon carbide crystals. No material deposition is recorded as Y, and material deposition is recorded as N. The results are shown in Table 1.

[0098] Table 1

[0099] Raman spectrum of 4H-SiC Raman spectrum of 3C-SiC Deposition condition of exhaust pipe Example 2 <![CDATA[204 cm -1 , 777 cm -1 , 971 cm -1 > <![CDATA[796cm -1 ,972cm -1 > Y Example 3 <![CDATA[204cm -1 ,777cm -1 ,971cm -1 > <![CDATA[796cm -1 ,972cm -1 > Y Example 4 <![CDATA[204cm -1 ,777cm -1 ,971cm -1 > <![CDATA[796cm -1 ,972cm -1 > Y Example 5 <![CDATA[204cm -1 ,777cm -1 ,971cm -1 > <![CDATA[796cm -1 ,972cm -1 > Y Comparative Example 1 <![CDATA[204cm -1 ,777cm -1 ,971cm -1 > / N Comparative Example 2 / <![CDATA[796cm -1 ,972cm -1 > N

[0100] The applicant declares that the detailed structural features of the present invention are illustrated by the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the components selected for the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

[0101] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0102] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any suitable manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0103] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. An apparatus for preparing silicon carbide crystals by HTCVD method, characterized in that, The device includes a crucible, and a first chamber and a second chamber which are arranged inside the crucible and are connected in sequence along the gas source flow direction. The first chamber and the second chamber are connected through a gas pipeline; The first chamber is sequentially provided with a first gas source pipeline and a first silicon carbide growth region along the gas source flow direction; The second chamber is sequentially provided with a second gas source pipeline and a second silicon carbide growth region along the gas source flow direction.

2. The device for preparing silicon carbide crystals by the HTCVD method according to claim 1, wherein, The first gas source pipeline includes a silicon source pipeline and a carbon source pipeline arranged around the silicon source pipeline.

3. The device for preparing silicon carbide crystals by the HTCVD method according to claim 1, characterized in that, The first silicon carbide growth region is provided with a first seed crystal, and the first seed crystal is connected to the top of the first chamber through a first seed crystal support assembly.

4. The apparatus for preparing silicon carbide crystals by the HTCVD method according to claim 3, characterized in that, The first seed crystal is a silicon carbide seed crystal.

5. The device for preparing silicon carbide crystals by the HTCVD method according to claim 1, characterized in that, A gas source inlet is arranged at the bottom of the first chamber.

6. The device for preparing silicon carbide crystals by the HTCVD method according to claim 1, characterized in that, The second silicon carbide growth region is provided with a second seed crystal, and the second seed crystal is connected to the top of the second chamber through a second seed crystal support assembly.

7. The apparatus for preparing silicon carbide crystals by the HTCVD method according to claim 6, characterized in that, The second seed crystal is a single crystal silicon seed crystal.

8. A method for preparing silicon carbide crystals by HTCVD method, characterized in that, The method uses the device for preparing silicon carbide crystals by the HTCVD method according to any one of claims 1-7. The method includes: Heating the first silicon carbide growth region and the second silicon carbide growth region to the silicon carbide growth temperature independently and separately; Introducing a carrier gas, a silicon source gas and a carbon source gas. The carrier gas, the silicon source gas and the carbon source gas reach the first silicon carbide growth region through the first gas source pipeline for single crystal silicon carbide growth; The unreacted silicon source gas and carbon source gas enter the second chamber through the gas pipeline, reach the second silicon carbide growth region through the second gas source pipeline, and perform polycrystalline silicon carbide growth.

9. The method for preparing a silicon carbide crystal by the HTCVD method according to claim 8, characterized in that, The flow rate of the carrier gas is 35-50 slm, the flow rate of the silicon source gas is 200-450 sccm, and the flow rate of the carbon source gas is 80-150 sccm.

10. The method for preparing a silicon carbide crystal by the HTCVD method according to claim 8, characterized in that, The growth temperature of the single crystal silicon carbide is 2100-2300 °C, and the growth pressure is 200-300 mbar; The growth temperature of the polycrystalline silicon carbide is 1200-1400 °C, and the growth pressure is 200-300 mbar.

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