Growth method for improving epitaxial doping concentration stability of silicon carbide and epitaxial wafer

Abstract

The invention discloses a growth method for improving epitaxial doping concentration stability of silicon carbide and an epitaxial wafer. The growth method comprises the following steps: S1, performing high vacuum pumping and low-temperature baking treatment on a reaction cavity; s2, conveying the substrate into a reaction cavity, heating and depressurizing the reaction cavity, and introducing hydrogen into the reaction cavity; s3, introducing hydrogen and HCl gas into the reaction cavity, and performing in-situ etching on the silicon carbide substrate; s4, introducing hydrogen and a carbon source into the reaction cavity, and adjusting the temperature of the reaction cavity to an epitaxial temperature; s5, introducing a silicon source, a carbon source, hydrogen and a doping source ammonia gas into the reaction cavity, and growing a buffer layer; s6, increasing the introduction amount of the silicon source, the carbon source, the hydrogen and the doping source ammonia gas, adjusting the carbon-silicon ratio, and growing a main epitaxial layer; s7, introducing hydrogen into the reaction cavity, and performing low-temperature baking and etching; and S8, after epitaxial growth is completed, closing the reaction gas, cooling and boosting, and taking out the silicon carbide epitaxial wafer.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor preparation, and in particular to a growth method and an epitaxial wafer for improving the stability of silicon carbide epitaxial doping concentration. Background Art

[0002] As a third-generation wide bandgap semiconductor material, 4H-SiC has very excellent material properties in terms of thermal conductivity, critical breakdown field strength, operating temperature, saturated electron drift velocity, etc. compared with traditional Si and GaAs materials. SiC has unique stability, applicability and outstanding performance, which meets the major national strategic needs such as energy conservation and emission reduction, intelligent manufacturing, and information security. It is regarded as one of the key core materials supporting the innovative development and transformation and upgrading of industries such as the new generation of new energy vehicles, high-speed rail trains, high-voltage power grids, and photovoltaics, and has become the focus of global semiconductor technology and industry competition.

[0003] Almost all SiC devices are realized on epitaxial materials. High-quality 4H-SiC homoepitaxial materials are the basis for the development of SiC devices. The performance of epitaxial materials directly determines the realization of SiC device performance. High-current, high-reliability SiC devices have put forward more stringent requirements on the surface morphology, defect density, doping and thickness uniformity of epitaxial materials. Large-size, low-defect density and high-uniformity SiC epitaxial materials have become the key to the development of the SiC power electronics industry. How to better control the doping concentration stability of the epitaxial layer is crucial to the performance of SiC power devices, which directly determines the important electrical parameters of subsequent devices such as on-resistance and blocking voltage. In addition, due to the particularity of the SiC epitaxial process, the self-doping effect of the cavity and graphite parts will affect the stability of the doping concentration parameters and uniformity as the epitaxial thickness accumulates. How to better control the doping concentration stability of the SiC epitaxial layer is also crucial for continuous production and improving the quality of epitaxial wafers. Summary of the invention

[0004] Purpose of the invention: In view of the shortcomings of the prior art, such as poor doping concentration stability, high debugging cost and low production efficiency, the present invention provides a growth method and epitaxial wafer for improving the stability of silicon carbide epitaxial doping concentration. This method can control the stability of the doping concentration of silicon carbide epitaxial wafers, thereby improving the parameter quality of epitaxial wafers, improving the yield of silicon carbide device wafers, and reducing the cost of debugging and verification, thereby ensuring the continuity of epitaxial production and greatly improving the output efficiency of a single machine.

[0005] Technical solution: To solve the above problems, the present invention adopts a growth method for improving the stability of silicon carbide epitaxial doping concentration, comprising the following steps:

[0006] S1, evacuate the reaction chamber to a high vacuum and perform low-temperature baking treatment;

[0007] S2, transferring the substrate into the reaction chamber, increasing the temperature and reducing the pressure of the reaction chamber, and introducing hydrogen into the reaction chamber;

[0008] S3, introducing hydrogen and HCl gas into the reaction chamber to perform in-situ etching on the silicon carbide substrate;

[0009] S4, introducing hydrogen and carbon source into the reaction chamber, and adjusting the temperature of the reaction chamber to the epitaxial temperature;

[0010] S5, introducing silicon source, carbon source, hydrogen and doping source ammonia into the reaction chamber to grow a buffer layer;

[0011] S6, increasing the amount of silicon source, carbon source, hydrogen and doping source ammonia introduced, adjusting the carbon-silicon ratio, and growing the main epitaxial layer;

[0012] S7, introducing hydrogen into the reaction chamber to perform low-temperature baking and etching;

[0013] S8. After the epitaxial growth is completed, the reaction gas is turned off, the temperature is lowered and the pressure is increased, and the silicon carbide epitaxial wafer is taken out.

[0014] Furthermore, in step S1, the pressure of the reaction chamber is first controlled at 1E -5 -1E -4 mbar, the target temperature in the reaction chamber is 1100-1400℃. After reaching the target temperature, maintain it for 1-3 hours, then restore the reaction chamber temperature to 900℃, restore the pressure to 1000mbar, and introduce flotation argon and hydrogen.

[0015] Furthermore, in step S2, the reaction chamber temperature is raised to 1630-1700°C, the reaction chamber pressure is reduced to 80-150mbar, the hydrogen flow rate is 100-160slm, the flotation argon flow rate is 1.8-2.5slm, the ramp time is 5-10mins, and the gas is kept stably flowing for 2-4mins.

[0016] Furthermore, in step S3, the hydrogen flow rate is 100-160 slm, the HCl gas flow rate is 120-220 sccm, and the etching time is 4-8 mins.

[0017] Furthermore, in step S4, the reaction chamber temperature is set to 1600-1650°C, and the reaction chamber temperature of step S4 is lower than that of step S2, and the cooling time is 2-4 minutes; the hydrogen flow rate is 100-160 slm, and the carbon source gas flow rate is 200-300 sccm, and the gas is kept stably flowing for 2-4 minutes.

[0018] Furthermore, in step S5, the silicon source pipeline pressure is 1500-2500mbar, the silicon source pipeline temperature is 30-60°C, and the silicon source gas hydrogen flow rate is 100-200sccm; the carbon source gas flow rate is 50-100sccm, and the hydrogen flow rate is 800-1600sccm, and the hydrogen is used to dilute the doping source ammonia; the ammonia pipeline pressure is 1500-2500mbar, the ammonia pipeline temperature is 60-100°C, the ammonia flow rate is 80-150sccm, and the ammonia concentration is 3000-6000ppm; the reaction C / Si ratio in the reaction chamber is 0.5-0.7, and the gas is kept stable for 2-5min.

[0019] Furthermore, in step S6, the silicon source gas flow rate is increased to 600-800 sccm, the carbon source gas flow rate is increased to 300-400 sccm, the hydrogen flow rate is increased to 1200-2200 sccm, the ammonia flow rate is increased to 300-800 sccm, the ramp time is 1-3 minutes, and the reaction C / Si ratio in the reaction chamber is 0.9-1.1.

[0020] Furthermore, in step S7, the hydrogen flow rate is 20-60 slm, the reaction chamber temperature is 1350-1400° C., and the gas is kept flowing stably for 1-3 minutes.

[0021] Furthermore, the silicon source is trichlorosilane, and the carbon source is ethylene.

[0022] The present invention also provides an epitaxial wafer produced by the growth method for improving the stability of silicon carbide epitaxial doping concentration.

[0023] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) ethylene gas is pre-introduced before epitaxial growth, so that the chamber is in a carbon-rich environment. Since nitrogen atoms and carbon atoms compete for lattice positions during epitaxial growth, the doping efficiency of nitrogen atoms can be reduced in a carbon-rich environment, thereby improving the stability of epitaxial doping concentration; (2) by vacuumizing the chamber and performing low-temperature baking before and after epitaxial growth, the impurity content of the chamber and graphite parts can be effectively reduced, and the background doping level in the chamber can be reduced, which is beneficial to the control of the stability of the doping concentration during the epitaxial process; (3) the doping source uses ammonia gas of a specific concentration instead of nitrogen gas, and utilizes the active physical and chemical properties of ammonia gas. Epitaxial doping is performed after dilution in a specific ratio, which can achieve better uniformity of doping concentration and a stable trend; (4) Compared with the existing process, the present invention also reduces the debugging cost and greatly improves the output efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall process of the growth method of the present invention;

[0025] Figure 2This is a graph showing the test results of the mean concentration and concentration uniformity of the epitaxial wafer obtained in Example 1;

[0026] Figure 3 This is a graph showing the test results of the mean concentration and concentration uniformity of the epitaxial wafer obtained in Example 2;

[0027] Figure 4 The figure is a test result diagram of the mean concentration and concentration uniformity of the epitaxial wafer obtained in Example 3;

[0028] Figure 5 It is a comparison chart of test and output data related to three embodiments of the present invention and the existing process. DETAILED DESCRIPTION

[0029] Embodiment 1

[0030] like Figure 1 As shown, a growth method for improving the stability of silicon carbide epitaxial doping concentration in this embodiment includes the following steps:

[0031] S1. Pump the reaction chamber to a high vacuum and bake it out at a low temperature. After the silicon carbide epitaxial furnace is maintained or a new graphite part is replaced, the reaction chamber pressure is controlled at 1E by the combined action of a dry pump and a molecular pump. -5 mbar range. The machine is temperature controlled in PID mode, the target temperature of the reaction chamber is 1100℃, the heating rate is controlled at 20℃ / min, and after reaching the target temperature, it is maintained for 1 hour. Then the temperature of the reaction chamber is restored to 900℃, the pressure is restored to 1000mbar, and flotation argon and hydrogen are introduced. The flotation argon flow rate is 0.1slm, the tray starts to rotate, and the hydrogen flow rate is 50slm.

[0032] S2. Transfer the substrate into the reaction chamber, raise the temperature of the reaction chamber to 1630°C, reduce the pressure of the reaction chamber to 80mbar, and continuously introduce flotation argon and hydrogen. The hydrogen flow rate is 100slm, the flotation argon flow rate is 1.8slm, the ramp time is 5mins, and the gas is kept stable for 2mins.

[0033] S3, hydrogen and HCl gas are introduced into the reaction chamber to perform in-situ etching on the silicon carbide substrate. The hydrogen flow rate is 100 slm, the HCl gas flow rate is 120 ccm, the flotation argon flow rate is 1.8 slm, and the etching time is 4 minutes.

[0034] S4, hydrogen and ethylene are introduced into the reaction chamber, and the temperature of the reaction chamber is adjusted to the epitaxial temperature. The temperature of the reaction chamber is cooled to 1600°C, and the cooling time is controlled within 2 minutes. Hydrogen and ethylene are introduced into the reaction chamber, and the hydrogen gas flow rate is controlled at 100 slm, and the ethylene gas flow rate is controlled at 200 sccm. The stabilization time is controlled for 2 minutes.

[0035] S5. Introduce trichlorosilane (TCS), ethylene, hydrogen and doping source ammonia into the reaction chamber to grow a buffer layer. The pressure of the trichlorosilane pipeline is 1500mbar, the temperature of the trichlorosilane pipeline is 30°C, and the trichlorosilane hydrogen flow rate is 100sccm. The ethylene flow rate is 50sccm, and the hydrogen flow rate is 800sccm. The hydrogen is used to dilute the doping source ammonia. The ammonia pipeline pressure is 1500mbar, the ammonia pipeline temperature is 60°C, the ammonia flow rate is 80sccm, and the ammonia concentration is 3000ppm; the reaction C / Si ratio in the reaction chamber is 0.5, and the gas is kept stable for 2mins.

[0036] S6, increase the amount of trichlorosilane, ethylene, hydrogen and doping source ammonia, adjust the carbon-silicon ratio, and grow the main epitaxial layer. Adjust the reaction C / Si ratio in the reaction chamber to 0.9, increase the trichlorosilane hydrogen flow rate to 600sccm, the ethylene flow rate to 300sccm, the hydrogen flow rate to 1200sccm, the ammonia flow rate to 300sccm, the ramp time to 1min, and keep the gas stable for a period of time. The stabilization time is adjusted according to the epitaxial target thickness.

[0037] S7, hydrogen is introduced into the reaction chamber for low-temperature baking and etching. The hydrogen flow rate is 20 slm, the reaction chamber temperature is 1350°C, and the gas is kept introduced stably for 1 minute.

[0038] S8. After the epitaxial growth is completed, the reaction gas is turned off, the temperature is lowered and the pressure is increased, and the silicon carbide epitaxial wafer is taken out.

[0039] Embodiment 2

[0040] A growth method for improving the stability of silicon carbide epitaxial doping concentration in this embodiment includes the following steps:

[0041] S1. Pump the reaction chamber to a high vacuum and bake it out at a low temperature. After the silicon carbide epitaxial furnace is maintained or a new graphite part is replaced, the reaction chamber pressure is controlled at 1E by the combined action of a dry pump and a molecular pump. -5 -1E - 4 mbar range. The machine is temperature controlled in PID mode, the target temperature of the reaction chamber is 1300℃, the heating rate is controlled at 20℃ / min, and after reaching the target temperature, it is maintained for 2 hours. Then the temperature of the reaction chamber is restored to 900℃, the pressure is restored to 1000mbar, and flotation argon and hydrogen are introduced. The flotation argon flow rate is 0.1slm, the tray starts to rotate, and the hydrogen flow rate is 50slm.

[0042] S2. Transfer the substrate into the reaction chamber, raise the temperature of the reaction chamber to 1660°C, reduce the pressure of the reaction chamber to 120mbar, and continuously introduce flotation argon and hydrogen. The hydrogen flow rate is 130slm, the flotation argon flow rate is 2.1slm, the ramp time is 7mins, and the gas is kept stable for 3mins.

[0043] S3, hydrogen and HCl gas are introduced into the reaction chamber to perform in-situ etching on the silicon carbide substrate. The hydrogen flow rate is 130 slm, the HCl gas flow rate is 160 ccm, the floating argon gas flow rate is 2.1 slm, and the etching time is 6 minutes.

[0044] S4, hydrogen and ethylene are introduced into the reaction chamber, and the temperature of the reaction chamber is adjusted to the epitaxial temperature. The temperature of the reaction chamber is cooled to 1630°C, and the cooling time is controlled within 3 minutes. Hydrogen and ethylene are introduced into the reaction chamber, and the hydrogen gas flow rate is controlled at 130 slm, and the ethylene gas flow rate is controlled at 250 sccm. The stabilization time is controlled for 3 minutes.

[0045] S5. Introduce trichlorosilane (TCS), ethylene, hydrogen and doping source ammonia into the reaction chamber to grow a buffer layer. The pressure of the trichlorosilane pipeline is 2000mbar, the temperature of the trichlorosilane pipeline is 45°C, and the trichlorosilane hydrogen flow rate is 150sccm. The ethylene flow rate is 75sccm, and the hydrogen flow rate is 1200sccm. The hydrogen is used to dilute the doping source ammonia. The ammonia pipeline pressure is 2000mbar, the ammonia pipeline temperature is 80°C, the ammonia flow rate is 120sccm, and the ammonia concentration is 4500ppm; the reaction C / Si ratio in the reaction chamber is 0.6, and the gas is kept stable for 4mins.

[0046] S6, increase the amount of trichlorosilane, ethylene, hydrogen and doping source ammonia gas introduced, adjust the carbon-silicon ratio, and grow the main epitaxial layer. Adjust the reaction C / Si ratio in the reaction chamber to 1, increase the trichlorosilane hydrogen flow rate to 700sccm, the ethylene flow rate to 350sccm, the hydrogen flow rate to 1700sccm, the ammonia flow rate to 500sccm, set the ramp time to 2min, and keep the gas stable for a period of time. The stabilization time is adjusted according to the epitaxial target thickness.

[0047] S7, hydrogen is introduced into the reaction chamber for low-temperature baking and etching. The hydrogen flow rate is 40 slm, the reaction chamber temperature is 1380°C, and the gas is kept introduced stably for 2 minutes.

[0048] S8. After the epitaxial growth is completed, the reaction gas is turned off, the temperature is lowered and the pressure is increased, and the silicon carbide epitaxial wafer is taken out.

[0049] Embodiment 3

[0050] A growth method for improving the stability of silicon carbide epitaxial doping concentration in this embodiment includes the following steps:

[0051] S1. Pump the reaction chamber to a high vacuum and bake it out at a low temperature. After the silicon carbide epitaxial furnace is maintained or a new graphite part is replaced, the reaction chamber pressure is controlled at 1E by the combined action of a dry pump and a molecular pump. -4 mbar range. The machine is in PID mode for temperature control, the target temperature of the reaction chamber is 1400℃, the heating rate is controlled at 20℃ / min, and after reaching the target temperature, it is maintained for 3 hours. Then the temperature of the reaction chamber is restored to 900℃, the pressure is restored to 1000mbar, and flotation argon and hydrogen are introduced. The flotation argon flow rate is 0.1slm, the tray starts to rotate, and the hydrogen flow rate is 50slm.

[0052] S2. Transfer the substrate into the reaction chamber, raise the temperature of the reaction chamber to 1700°C, reduce the pressure of the reaction chamber to 150mbar, and continuously introduce flotation argon and hydrogen. The hydrogen flow rate is 160slm, the flotation argon flow rate is 2.5slm, the ramp time is 10mins, and the gas is kept stable for 4mins.

[0053] S3, hydrogen and HCl gas are introduced into the reaction chamber to perform in-situ etching on the silicon carbide substrate. The hydrogen flow rate is 160 slm, the HCl gas flow rate is 200 ccm, the flotation argon gas flow rate is 2.5 slm, and the etching time is 8 minutes.

[0054] S4, hydrogen and ethylene are introduced into the reaction chamber, and the temperature of the reaction chamber is adjusted to the epitaxial temperature. The temperature of the reaction chamber is cooled to 1650°C, and the cooling time is controlled within 4 minutes. Hydrogen and ethylene are introduced into the reaction chamber, and the hydrogen gas flow rate is controlled at 160 slm, and the ethylene gas flow rate is controlled at 300 sccm. The stabilization time is controlled for 4 minutes.

[0055] S5. Introduce trichlorosilane (TCS), ethylene, hydrogen and doping source ammonia into the reaction chamber to grow a buffer layer. The pressure of the trichlorosilane pipeline is 2500mbar, the temperature of the trichlorosilane pipeline is 60°C, and the trichlorosilane hydrogen flow rate is 200sccm. The ethylene flow rate is 100sccm, and the hydrogen flow rate is 1600sccm. The hydrogen is used to dilute the doping source ammonia. The ammonia pipeline pressure is 2500mbar, the ammonia pipeline temperature is 100°C, the ammonia flow rate is 150sccm, and the ammonia concentration is 6000ppm; the reaction C / Si ratio in the reaction chamber is 0.7, and the gas is kept stable for 5mins.

[0056] S6, increase the amount of trichlorosilane, ethylene, hydrogen and doping source ammonia, adjust the carbon-silicon ratio, and grow the main epitaxial layer. Adjust the reaction C / Si ratio in the reaction chamber to 1.1, increase the trichlorosilane hydrogen flow rate to 800sccm, the ethylene flow rate to 400sccm, the hydrogen flow rate to 2200sccm, and the ammonia flow rate to 800sccm, set the ramp time to 1min, and keep the gas stable for a period of time, and adjust the stabilization time according to the epitaxial target thickness.

[0057] S7, hydrogen is introduced into the reaction chamber for low-temperature baking and etching. The hydrogen flow rate is 60 slm, the reaction chamber temperature is 1400°C, and the gas is kept introduced stably for 3 minutes.

[0058] S8. After the epitaxial growth is completed, the reaction gas is turned off, the temperature is lowered and the pressure is increased, and the silicon carbide epitaxial wafer is taken out.

[0059] The epitaxial concentration mean and concentration uniformity of the silicon carbide epitaxial wafers obtained in the three embodiments of the present invention were tested. The test results of the first to sixth furnaces are as follows: Figures 2 to 4 As shown in the figure, the concentration averages of the three embodiments for six consecutive furnaces are relatively stable, with a deviation of less than 1%; the uniformity of doping concentration is also stably controlled, with a deviation of less than 1% for six consecutive furnaces. The results show that the background doping concentration of the chamber after treatment is low, the doping furnace drift is small, and the stability of doping concentration is effectively improved. Figure 5 As shown, compared with the existing process, the process of the present invention can also reduce the waiting time for process testing and debugging, reduce the debugging cost, and greatly increase the number of output furnaces.

[0060] The present invention pre-introduces ethylene gas before epitaxial growth, so that the chamber is in a carbon-rich environment. Since nitrogen atoms and carbon atoms compete for lattice positions during epitaxial growth, the doping efficiency of nitrogen atoms can be reduced in a carbon-rich environment, thereby improving the stability of epitaxial doping concentration. By vacuumizing the chamber and performing low-temperature baking before and after epitaxial growth, the impurity content of the cavity and graphite parts can be effectively reduced, and the background doping level in the chamber can be reduced, which is beneficial to the control of the stability of the doping concentration during the epitaxial process. In addition, the doping source uses ammonia of a specific concentration instead of nitrogen, and utilizes the active physical and chemical properties of ammonia. Epitaxial doping is performed after dilution in a specific ratio, which can achieve better uniformity of doping concentration and a stable trend. Compared with the existing process, the present invention also reduces the debugging cost and greatly improves the output efficiency.

Claims

1. A growth method for improving the stability of silicon carbide epitaxial doping concentration, characterized in that: The following steps are involved: S1, evacuate the reaction chamber to a high vacuum and perform low-temperature baking treatment; S2, transferring the substrate into the reaction chamber, increasing the temperature and reducing the pressure of the reaction chamber, and introducing hydrogen into the reaction chamber; S3, introducing hydrogen and HCl gas into the reaction chamber to perform in-situ etching on the silicon carbide substrate; S4, introducing hydrogen and carbon source into the reaction chamber, and adjusting the temperature of the reaction chamber to the epitaxial temperature; S5, introducing silicon source, carbon source, hydrogen and doping source ammonia into the reaction chamber to grow a buffer layer; S6, increasing the amount of silicon source, carbon source, hydrogen and doping source ammonia introduced, adjusting the carbon-silicon ratio, and growing the main epitaxial layer; S7, introducing hydrogen into the reaction chamber to perform low-temperature baking and etching; S8. After the epitaxial growth is completed, the reaction gas is turned off, the temperature is lowered and the pressure is increased, and the silicon carbide epitaxial wafer is taken out.

2. The growth method according to claim 1, characterized in that In step S1, the pressure of the reaction chamber is first controlled at 1E -5 -1E -4 mbar, the target temperature in the reaction chamber is 1100-1400℃. After reaching the target temperature, maintain it for 1-3 hours, then restore the reaction chamber temperature to 900℃, restore the pressure to 1000mbar, and introduce flotation argon and hydrogen.

3. The growth method according to claim 2, characterized in that In step S2, the reaction chamber temperature is raised to 1630-1700°C, the reaction chamber pressure is reduced to 80-150mbar, the hydrogen flow rate is 100-160slm, the flotation argon flow rate is 1.8-2.5slm, the ramp time is 5-10mins, and the gas is kept stably flowing for 2-4mins.

4. The growth method according to claim 1, characterized in that In step S3, the hydrogen flow rate is 100-160 slm, the HCl gas flow rate is 120-220 sccm, and the etching time is 4-8 mins.

5. The growth method according to claim 1 or 3, characterized in that: In step S4, the reaction chamber temperature is set to 1600-1650°C, and the reaction chamber temperature of step S4 is lower than that of step S2, and the cooling time is 2-4 minutes; the hydrogen flow rate is 100-160 slm, the carbon source gas flow rate is 200-300 sccm, and the gas is kept stably flowing for 2-4 minutes.

6. The growth method according to claim 1, characterized in that In step S5, the silicon source pipeline pressure is 1500-2500mbar, the silicon source pipeline temperature is 30-60°C, and the silicon source gas hydrogen flow rate is 100-200sccm; the carbon source gas flow rate is 50-100sccm, and the hydrogen flow rate is 800-1600sccm, and the hydrogen is used to dilute the doping source ammonia; the ammonia pipeline pressure is 1500-2500mbar, the ammonia pipeline temperature is 60-100°C, the ammonia flow rate is 80-150sccm, and the ammonia concentration is 3000-6000ppm; the reaction C / Si ratio in the reaction chamber is 0.5-0.7, and the gas is kept stable for 2-5min.

7. The growth method according to claim 1, characterized in that In step S6, the silicon source gas flow rate is increased to 600-800 sccm, the carbon source gas flow rate is increased to 300-400 sccm, the hydrogen flow rate is increased to 1200-2200 sccm, the ammonia flow rate is increased to 300-800 sccm, the ramp time is 1-3 minutes, and the reaction C / Si ratio in the reaction chamber is 0.9-1.

1.

8. The growth method according to claim 1, characterized in that In step S7, the hydrogen flow rate is 20-60 slm, the reaction chamber temperature is 1350-1400°C, and the gas is kept flowing stably for 1-3 minutes.

9. The growth method according to claim 1, characterized in that The silicon source is trichlorosilane, and the carbon source is ethylene.

10. An epitaxial wafer produced according to the growth method for improving the stability of epitaxial doping concentration of silicon carbide according to any one of claims 1 to 9.

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