Method for manufacturing silicon carbide epitaxial wafer and manufacturing apparatus

Abstract

The application provides a silicon carbide epitaxial wafer preparation method and a preparation device. The preparation method comprises the following steps: providing a substrate, placing the substrate in an epitaxial reaction cavity; heating the substrate, controlling the substrate to have a distance H mm from a heated heat source, and the epitaxial reaction cavity has a reaction temperature T ℃; introducing a carrier gas, a growth source and a doping source to prepare an epitaxial layer on the surface of the substrate to obtain a silicon carbide epitaxial wafer; wherein the distance H mm and the reaction temperature T ℃ satisfy: 5.5≤(T-1500) / H≤7. By controlling the distance between the substrate and the heated heat source to adjust the air flow and the temperature field on the surface of the substrate, the temperature difference between the center and the edge of the wafer is reduced, thereby reducing the triangular defects on the surface of the wafer; at the same time, the distance between the substrate and the heated heat source cooperates with the temperature in the epitaxial reaction cavity, which can ensure the growth rate of the epitaxial layer and reduce the triangular defects while avoiding the occurrence of step defects, thereby improving the overall quality of the epitaxial wafer.

Description

Technical Field

[0001] This application belongs to the field of semiconductor manufacturing technology, specifically relating to a method and apparatus for preparing silicon carbide epitaxial wafers. Background Technology

[0002] Silicon carbide (SiC) is a novel semiconductor material. Compared to silicon wafers, SiC exhibits greater bandwidth and higher thermal conductivity, enabling it to operate in high-frequency and high-power applications. This makes SiC wafers promising for applications in wireless communication, radar systems, and power transmission. However, despite significant breakthroughs and rapid development in SiC technology, poor surface quality of its epitaxial layers and high fabrication costs are two major factors limiting its industrialization. Currently, defects such as triangular defects, droplets, and carrot-shaped defects in SiC epitaxial layers are considered fatal. For example, triangular defects in the epitaxial layer can reduce the breakdown voltage of electronic devices such as JBS, SBD, MOSFET, BJT, and IGBT by approximately 50%-90%.

[0003] Existing processes can control triangular defects by increasing temperature. As the temperature increases, silicon vapor nucleation is suppressed, thereby reducing the number of triangular defects on the epitaxial layer surface. However, as the temperature rises, step defects appear on the epitaxial layer surface. The accumulation of step defects increases the leakage current in the Schottky diode, leading to a decrease in breakdown voltage. Summary of the Invention

[0004] This invention provides a method and apparatus for preparing silicon carbide epitaxial wafers, aiming to solve the problems of triangular defects and step defects that occur during the growth of existing silicon carbide epitaxial wafers.

[0005] The first embodiment of this application provides a method for preparing a silicon carbide epitaxial wafer, comprising the following steps:

[0006] A substrate is provided and placed inside an epitaxial reaction chamber;

[0007] The substrate is heated, and the distance between the substrate and the heat source is controlled to be H mm. The epitaxial reaction chamber has a reaction temperature T °C.

[0008] By introducing a carrier gas, a growth source, and a doping source, an epitaxial layer is prepared on the surface of the substrate to obtain the silicon carbide epitaxial wafer;

[0009] Wherein, the distance H mm and the reaction temperature T °C satisfy:

[0010] 5.5≤(T-1500) / H≤7.

[0011] In some embodiments, the carrier gas has a first flow velocity Q1 slm, satisfying:

[0012] 1680≤H·Q1≤2570.

[0013] In some embodiments, the growth source has a second flow rate Q2 sccm, and the doping source has a third flow rate Q3 sccm, satisfying:

[0014] Q1: Q2: Q3=1~1.5: 1~5: 0.5~4.

[0015] In some embodiments, the distance H mm further satisfies: 16.8 ≤ H ≤ 19.8.

[0016] In some embodiments, the reaction temperature T℃ further satisfies: 1580≤T≤1640.

[0017] In some embodiments, the first flow rate Q1 slm further satisfies: 100≤Q1≤130.

[0018] In some embodiments, the second flow rate Q2 slm further satisfies: 120≤Q2≤470.

[0019] In some embodiments, the third flow rate Q3 slm further satisfies: 50 ≤ Q3 ≤ 400.

[0020] In some embodiments, the carrier gas includes hydrogen.

[0021] In some embodiments, the growth source includes a carbon source and a silicon source.

[0022] In some embodiments, the doping source includes a nitrogen source.

[0023] In some embodiments, the flow rate ratio of the carbon source to the silicon source is 1-3:2-9.

[0024] In some embodiments, the carbon source includes at least one of ethylene and propane.

[0025] In some embodiments, the silicon source includes at least one of trimethylsilyl chloride and silane.

[0026] In some embodiments, the nitrogen source includes at least one of ammonia and nitrogen.

[0027] In some embodiments, the step of introducing a carrier gas, a growth source, and a dopant source further includes:

[0028] Inert gas is introduced;

[0029] The flow rate of the inert gas is 0.5 to 1.0 slm.

[0030] In some embodiments, during the step of preparing an epitaxial layer on the substrate surface, the pressure inside the epitaxial reaction chamber is 80–100 mbar.

[0031] The second embodiment of this application provides an apparatus for preparing a silicon carbide epitaxial wafer, used to implement the method for preparing a silicon carbide epitaxial wafer in any of the above embodiments, including:

[0032] The support portion is used to support the substrate;

[0033] A heating element is provided for heating the substrate. The heating element is located on the side of the support element away from the substrate and is detachably connected to the support element.

[0034] In some embodiments, the apparatus for fabricating silicon carbide epitaxial wafers further includes a connecting portion;

[0035] The supporting part is provided with a first placement groove, the heating part is provided with a second placement groove corresponding to the first placement groove, and the connecting part is simultaneously disposed in the first placement groove and the second placement groove.

[0036] In some embodiments, along the thickness direction of the support portion, there is a first dimension D between the side of the connection portion near the substrate and the side of the support portion away from the substrate, satisfying: 5.75mm≤D≤5.95mm.

[0037] This application provides a method for preparing a silicon carbide epitaxial wafer, comprising the following steps: providing a substrate and placing the substrate in an epitaxial reaction chamber; heating the substrate, controlling the distance H mm between the substrate and the heat source, and maintaining a reaction temperature T °C within the epitaxial reaction chamber; introducing a carrier gas, a growth source, and a doping source to prepare an epitaxial layer on the substrate surface, thereby obtaining a silicon carbide epitaxial wafer; wherein the distance H mm and the reaction temperature T °C satisfy: 5.5 ≤ (T - 1500) / H ≤ 7. By controlling the distance between the substrate and the heat source to adjust the airflow and temperature field on the substrate surface, the temperature difference between the wafer center and the edge is reduced, thereby reducing triangular defects on the wafer surface; simultaneously, the distance between the substrate and the heat source, combined with the temperature within the epitaxial reaction chamber, can ensure the epitaxial layer growth rate and reduce triangular defects while avoiding step defects, thereby improving the overall quality of the epitaxial wafer. Attached Figure Description

[0038] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0039] Figure 1 A flowchart illustrating a method for preparing a silicon carbide epitaxial wafer, provided as an embodiment of this application;

[0040] Figure 2A structural diagram of a silicon carbide epitaxial wafer fabrication apparatus provided in this application embodiment;

[0041] Figure 3 This is a schematic diagram of a triangular defect on the surface of an epitaxial wafer.

[0042] Figure 4 The above figures show the surface defect test results of silicon carbide epitaxial wafers provided in the embodiments and comparative examples of this application.

[0043] Figure label:

[0044] 10-Supporting part, 11-First placement groove, 20-Heating part, 21-Second placement groove, 30-Connecting part, 100-Substrate, 200-Epipolar layer. Detailed Implementation

[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for mutual communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically limited. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0047] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure of this application, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit this application.

[0048] The first embodiment of this application provides a method for preparing a silicon carbide epitaxial wafer, such as... Figure 1 As shown, it includes the following steps:

[0049] S1. Provide a substrate 100 and place the substrate 100 in the epitaxial reaction chamber;

[0050] S2. Heat the substrate 100, and control the distance H mm between the substrate 100 and the heat source, and the reaction temperature T °C in the epitaxial reaction chamber.

[0051] S3. Introduce carrier gas, growth source and doping source to prepare epitaxial layer 200 on substrate 100 to obtain silicon carbide epitaxial wafer.

[0052] Wherein, the distance H mm and the reaction temperature T °C satisfy:

[0053] 5.5≤(T-1500) / H≤7.

[0054] It is understandable that the value of (T-1500) / H can be any value among 5.5, 6.0, 6.5, and 7.0, or a range between any two values. By statistically analyzing the length, width, and height of triangular defects in different regions of the epitaxial wafer, such as... Figure 3 As shown, the triangle at the center of the epitaxial wafer has a longer tail and more regular edges. This is due to the temperature difference between the center and the edge. The difference in airflow around the edge results in a lower edge temperature, leading to a more regular triangular defect. For the triangle at the center, the temperature is higher, and the growth rate is faster, resulting in a faster growth rate of 3C-SiC towards the height direction, thus causing a longer boundary between 3C-SiC and 4H-SiC. The distance between the substrate 100 and the heating source affects the temperature field on the surface of the substrate 100, which in turn affects the formation of triangular defects on the surface of the epitaxial wafer. By controlling the distance between the substrate and the heating source, the airflow and temperature field on the substrate surface can be adjusted, reducing the temperature difference between the wafer center and the edge, thereby reducing triangular defects on the wafer surface. Simultaneously, the distance between the substrate and the heating source, combined with the temperature within the epitaxial reaction chamber, can ensure the epitaxial layer growth rate and reduce triangular defects while avoiding step defects, thereby improving the overall quality of the epitaxial wafer.

[0055] In some embodiments, the carrier gas has a first flow velocity Q1 slm, satisfying:

[0056] 1680≤H·Q1≤2570.

[0057] It is understandable that the product of the distance H between the substrate 100 and the heating heat source and the first flow rate Q1 (unit: mm·slm) can be any value or a range between any two of the following: 1680, 1830, 1980, 2130, 2280, 2430, and 2570. Triangular defects in epitaxial wafers are mostly caused by debris falling off during the epitaxial layer growth process. When the etching carrier gas flow is large, loose silicon carbide particles in the cavity are more likely to fall onto the tray. Conversely, when the carrier gas flow is small, the growth rate of the epitaxial layer 200 may be too slow, and the etching effect may be insufficient, leading to surface defects. Furthermore, the distance between the substrate 100 and the heating heat source affects the airflow on the surface of the substrate 100. When the distance H mm and the carrier gas flow rate satisfy the above relationship, it can be ensured that the final epitaxial wafer has fewer defects.

[0058] In some embodiments, the growth source has a second flow rate Q2 sccm, and the doping source has a third flow rate Q3 sccm, satisfying:

[0059] Q1: Q2: Q3=1~1.5: 1~5: 0.5~4.

[0060] Understandably, during the growth of silicon carbide epitaxial wafers, the carrier gas can also act as a dilution gas to regulate the pressure within the epitaxial reaction chamber. Simultaneously, the ratio of carrier gas, growth source, and dopant source within the epitaxial reaction chamber affects the competition between C and N sites on the surface of epitaxial layer 200. Even if the C / N ratio is maintained at the same level, the amount of hydrogen acting as both dilution gas and carrier gas will affect the depletion of growth and doping gases along the growth path. This will further influence the C / Si ratio and N ratio on the actual surface of epitaxial layer 200, and consequently, the growth rate of epitaxial layer 200. Therefore, when the flow rate ratios of carrier gas, growth source, and dopant source satisfy the above-mentioned relationship, it can ensure that the final silicon carbide epitaxial wafer has ideal doping uniformity and good surface quality.

[0061] In some embodiments, the distance H mm further satisfies: 16.8 ≤ H ≤ 19.8.

[0062] It is understood that the distance H (in mm) can be any value or a range between any two of the following: 16.8, 17.3, 17.8, 18.3, 18.8, 19.3, and 19.8. When the distance H mm between the substrate 100 and the heating source meets the above-mentioned range, the airflow and temperature field on the surface of the substrate 100 can be further adjusted, reducing the temperature difference between the wafer center and the edge, thereby reducing triangular defects on the wafer surface.

[0063] In some embodiments, the reaction temperature T °C further satisfies: 1580 ≤ T ≤ 1640. It is understood that the value of the reaction temperature T (unit: °C) can be any value among 1580, 1600, 1620, and 1640, or a range between any two values.

[0064] In some embodiments, the first flow rate Q1 slm further satisfies: 100 ≤ Q1 ≤ 130. It is understood that the value of the first flow rate Q1 (in slm) can be any value among 100, 110, 120, and 130 or a range between any two values.

[0065] In some embodiments, the second flow rate Q2 slm further satisfies: 120 ≤ Q2 ≤ 470. It is understood that the value of the second flow rate Q2 (in slm) can be any value among 120, 200, 300, 400, and 470, or a range between any two values.

[0066] In some embodiments, the third flow velocity Q3 slm further satisfies: 50 ≤ Q3 ≤ 400. It is understood that the value of the third flow velocity Q3 (in slm) can be any value among 50, 100, 200, 300, and 400, or a range between any two values.

[0067] When the reaction temperature T℃, the first flow rate Q1 slm, the second flow rate Q2 slm, and the third flow rate Q3 slm meet the above value range, the internal lattice structure of the silicon carbide epitaxial wafer can be further optimized, while reducing defects such as triangular defects on the outer surface.

[0068] In some embodiments, the carrier gas includes hydrogen.

[0069] In some embodiments, the growth source includes a carbon source and a silicon source.

[0070] In some embodiments, the doping source includes a nitrogen source.

[0071] In some embodiments, the flow rate ratio of the carbon source to the silicon source is 1–3:2–9.

[0072] It is understandable that the flow ratio of carbon source to silicon source can be any value or a range between any two values, such as 1:2, 1:3, 2:5, 3:8, 1:9. When the flow ratio of carbon source to silicon source meets the above range, the integrity of the crystal structure in the silicon carbide epitaxial wafer can be controlled, while ensuring that the epitaxial layer 200 has a reasonable growth rate and avoiding the occurrence of triangular defects and step defects.

[0073] In some embodiments, the carbon source includes at least one of ethylene and propane.

[0074] In some embodiments, the silicon source includes at least one of trimethylsilyl chloride and silane.

[0075] In some embodiments, the nitrogen source includes at least one of ammonia and nitrogen.

[0076] In some embodiments, the step of introducing a carrier gas, a growth source, and a dopant source further includes:

[0077] Inert gas is introduced;

[0078] The flow rate of the inert gas is 0.5–1.0 slm.

[0079] It is understandable that the flow rate of the inert gas (unit: slm) can be any value or a range between any two of 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0. The inert gas can act as a dilution gas to further regulate the pressure within the epitaxial reaction chamber, thereby controlling the growth rate of the epitaxial layer 200 and reducing the generation of triangular and step defects.

[0080] In some embodiments, the inert gas may be argon.

[0081] In some embodiments, during the step of preparing an epitaxial layer on the surface of substrate 100, the pressure inside the epitaxial reaction chamber is 80 to 100 mbar.

[0082] It is understandable that the pressure (unit: mbar) within the epitaxial reaction chamber can be any value or a range between any two of 80, 85, 90, 95, and 100. When the pressure within the epitaxial reaction chamber meets the above-mentioned range, the epitaxial layer 200 has an ideal growth rate, reducing the generation of triangular and step defects.

[0083] The second embodiment of this application provides an apparatus for preparing silicon carbide epitaxial wafers, used to implement the silicon carbide epitaxial wafer preparation method in any of the above embodiments, such as... Figure 2 As shown, it includes:

[0084] The support portion 10 is used to support the substrate 100;

[0085] The heating part 20 is used to heat the substrate 100. The heating part 20 is located on the side of the support part 10 away from the substrate 100 and is detachably connected to the support part 10.

[0086] Based on the above embodiments, such as Figure 2As shown, the support part 10 may include an air flotation tray and a graphite disk. The edge of the heating part 20 is provided with an annular boss to form a groove, so that the support part 10 can be detachably embedded in the groove of the heating part 20. When the carrier gas flow is introduced into the extended chamber, the air flow flows into the groove between the support part 10 and the heating part 20, suspending the air flotation tray on the top of the heating part 20 and causing the air flotation tray to rotate.

[0087] In some embodiments, such as Figure 2 As shown, the apparatus for fabricating silicon carbide epitaxial wafers also includes a connecting part 30;

[0088] The supporting part 10 is provided with a first placement groove 11, the heating part 20 is provided with a second placement groove 21 corresponding to the first placement groove 11, and the connecting part 30 is provided in both the first placement groove 11 and the second placement groove 21.

[0089] The connecting part 30 can further fix the bearing part 10. When the carrier gas flow is introduced into the extended cavity, the connecting part 30 can stabilize the relative position of the bearing part 10 and the heating part 20 during the rotation process and prevent displacement.

[0090] In some embodiments, along the thickness direction of the support portion 10, the side of the connecting portion 30 near the substrate 100 and the side of the support portion 10 away from the substrate 100 have a first dimension D, satisfying: 5.75mm≤D≤5.95mm.

[0091] It is understandable that the value of the first dimension D (unit: mm) can be any value between 5.75, 5.8, 5.85, 5.9, and 5.95, or any range between any two values. When the exposed height of the connecting part 30 relative to the heating part 20 is too high, it is easy to cause the rising position of the support part 10 to be too high, the thermal field to be affected, the temperature difference between the edge and the center to be large, the low temperature is not conducive to triangular conversion, and it will also cause the support part 10 to be unstable during rotation, causing it to shift, contact and friction with the connecting part 30, resulting in carbon powder overflow, wear of the connecting part 30, which is not conducive to the stability of growth, and may even cause the connecting part 30 to break. When the exposed height of the connecting part 30 relative to the heating part 20 is too low, it will cause the rising position of the support part 10 to be too low, the distance between the support part 10 and the heating part 20 to be too close, and it is easy to contact the base and cause friction, which will also cause carbon powder to overflow, affecting the particle size in the epitaxial reaction chamber, and making the rotation of the support part 10 unstable, affecting the film thickness and doping uniformity of the epitaxial layer 200. Therefore, when the first dimension D meets the above value range, it can ensure that the connecting part 30 has a reasonable exposure height, thereby controlling the epitaxial wafer to have fewer triangular defects, while having good thickness and doping uniformity.

[0092] The method and apparatus for preparing silicon carbide epitaxial wafers provided in this application are described below with reference to specific embodiments:

[0093] Example 1

[0094] This embodiment provides an apparatus and method for preparing silicon carbide epitaxial wafers, wherein the preparation apparatus is as follows: Figure 2 As shown, it includes:

[0095] The support portion 10 is used to support the substrate 100, and the support portion 10 is provided with a first placement groove 11;

[0096] The heating part 20 is used to heat the substrate 100. The heating part 20 is located on the side of the support part 10 away from the substrate 100 and is detachably connected to the support part 10. The heating part 20 is provided with a second placement groove 21 corresponding to the first placement groove 11.

[0097] The connecting part 30 is simultaneously disposed in the first placement groove 11 and the second placement groove 21.

[0098] The connecting part 30 has a first dimension D = 5.75 mm.

[0099] Silicon carbide epitaxial wafers are prepared using the above-described preparation apparatus, such as... Figure 1 As shown, the specific steps include the following:

[0100] S1. Provide a substrate 100 and place the substrate 100 in the epitaxial reaction chamber;

[0101] S2. Heat the substrate 100, and control the distance between the substrate 100 and the heat source to be H = 18 mm, and the reaction temperature in the epitaxial reaction chamber to be T = 1610℃.

[0102] S3. Introduce carrier gas, growth source and doping source to prepare epitaxial layer 200 on substrate 100 to obtain silicon carbide epitaxial wafer.

[0103] Example 2

[0104] The silicon carbide epitaxial wafer preparation apparatus and preparation method provided in Example 2 are the same as those in Example 1, except that another epitaxial reaction chamber is used and the first dimension D is adjusted, and the distance H between the substrate 100 and the heating heat source is changed accordingly.

[0105] Examples 3-4

[0106] The silicon carbide epitaxial wafers prepared in Examples 3 and 4 are the same as those in Example 2, except that the process parameters and the first dimension D are adjusted, and the distance H between the substrate 100 and the heating source is changed accordingly.

[0107] Comparative Examples 1-2

[0108] The silicon carbide epitaxial wafers prepared in Comparative Examples 1 and 2 are the same as those in Examples 1 to 4, except that the process parameters and the first dimension D are adjusted, and the distance H between the substrate 100 and the heating source is changed accordingly.

[0109] Comparative Examples 3-4

[0110] The silicon carbide epitaxial wafers prepared in Comparative Examples 3 and 4 are the same as those in Examples 1 and 4, except that the process parameters and the first dimension D are adjusted, and the distance H between the substrate 100 and the heating source is changed accordingly.

[0111] The relevant process parameters of Examples 1-4 and Comparative Examples 1-4 are shown in Table 1.

[0112] Table 1

[0113]

[0114]

[0115] The surface defects of the epitaxial wafers prepared in Examples 1-4 and Comparative Examples 1-4 were scanned and statistically analyzed using a surface defect tester (Candela 8520). The results are as follows: Figure 4 As shown.

[0116] according to Figure 4 As can be seen, the epitaxial wafers prepared by the scheme provided in this application show a significant reduction in triangular defects on their surface.

[0117] The foregoing has provided a detailed description of a silicon carbide epitaxial wafer preparation method and apparatus according to the embodiments of this application. Specific examples have been used in this application to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing a silicon carbide epitaxial wafer, characterized in that, Includes the following steps: A substrate (100) is provided and placed in an epitaxial reaction chamber; The substrate (100) is heated, and the distance between the substrate (100) and the heat source is controlled to be H mm. The epitaxial reaction chamber has a reaction temperature T ℃. By introducing a carrier gas, a growth source, and a doping source, an epitaxial layer (200) is prepared on the surface of the substrate (100) to obtain the silicon carbide epitaxial wafer; Wherein, the distance H mm and the reaction temperature T ℃ satisfy: 5.5≤(T-1500) / H≤7; The carrier gas has a first flow velocity Q1slm, satisfying: 1680≤H·Q1≤2570; The growth source has a second flow rate Q2 sccm, and the doping source has a third flow rate Q3 sccm, satisfying the following: Q1: Q2: Q3=1~1.5: 1~5: 0.5~4.

2. The method for preparing a silicon carbide epitaxial wafer according to claim 1, characterized in that, The distance H mm further satisfies: 16.8 ≤ H ≤ 19.

8.

3. The method for preparing a silicon carbide epitaxial wafer according to claim 1, characterized in that, The reaction temperature T℃ further satisfies: 1580≤T≤1640.

4. The method for preparing a silicon carbide epitaxial wafer according to claim 1, characterized in that, The first flow velocity Q1slm further satisfies: 100≤Q1≤130.

5. The method for preparing a silicon carbide epitaxial wafer according to claim 1, characterized in that, The second flow velocity Q2slm further satisfies: 120≤Q2≤470.

6. The method for preparing a silicon carbide epitaxial wafer according to claim 1, characterized in that, The third flow velocity Q3slm further satisfies: 50≤Q3≤400.

7. The method for preparing a silicon carbide epitaxial wafer according to claim 1, characterized in that, The carrier gas includes hydrogen; and / or, The growth source includes a carbon source and a silicon source; and / or, The doping source includes a nitrogen source.

8. The method for preparing a silicon carbide epitaxial wafer according to claim 7, characterized in that, The flow rate ratio of the carbon source to the silicon source is 1~3:2~9.

9. The method for preparing a silicon carbide epitaxial wafer according to claim 7, characterized in that, The carbon source includes at least one of ethylene and propane; and / or, The silicon source includes at least one of trimethylsilyl chloride and silane; and / or, The nitrogen source includes at least one of ammonia and nitrogen.

10. The method for preparing a silicon carbide epitaxial wafer according to claim 1, characterized in that, The steps of introducing the carrier gas, the growth source, and the dopant source further include: Inert gas is introduced; The flow rate of the inert gas is 0.5~1.0 slm.

11. The method for preparing a silicon carbide epitaxial wafer according to claim 1, characterized in that, In the step of preparing an epitaxial layer on the surface of the substrate (100), the pressure inside the epitaxial reaction chamber is 80~100mbar.

12. An apparatus for preparing a silicon carbide epitaxial wafer, used to implement the method for preparing a silicon carbide epitaxial wafer according to any one of claims 1 to 11, characterized in that, include: The support portion (10) is used to support the substrate (100), and the support portion (10) is provided with a first placement groove (11). A heating part (20) is used to heat the substrate (100). The heating part (20) is located on the side of the support part (10) away from the substrate (100) and is detachably connected to the support part (10). The heating part (20) is provided with a second placement groove (21) corresponding to the first placement groove (11). A connecting part (30) is provided in both the first placement groove (11) and the second placement groove (21); Wherein, along the thickness direction of the support portion (10), the side of the connecting portion (30) near the substrate (100) and the side of the support portion (10) away from the substrate (100) have a first dimension D, which satisfies: 5.75mm≤D≤5.95mm.

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