WO2017047244A1

WO2017047244A1 - Method for manufacturing silicon carbide epitaxial substrate and apparatus for silicon carbide epitaxial growth

Info

Publication number: WO2017047244A1
Application number: PCT/JP2016/072141
Authority: WO
Inventors: 土井　秀之; 和田　圭司; 健二平塚
Original assignee: 住友電気工業株式会社
Priority date: 2015-09-14
Filing date: 2016-07-28
Publication date: 2017-03-23

Abstract

This method for manufacturing a silicon carbide epitaxial substrate comprises: preheating nitrogen gas prior to introducing the nitrogen gas into a reactor containing a silicon carbide single crystal substrate; and introducing a gas mixture including carrier gas, raw gas, nitrogen gas, and ammonia gas into the reactor, and then epitaxially growing a nitrogen-doped silicon carbide layer on the silicon carbide single crystal substrate.

Description

Silicon carbide epitaxial substrate manufacturing method and silicon carbide epitaxial growth apparatus

The present disclosure relates to a method for manufacturing a silicon carbide epitaxial substrate and a silicon carbide epitaxial growth apparatus.

This application claims priority based on Japanese Application No. 2015-180664 filed on Sep. 14, 2015, and incorporates all the contents described in the Japanese application.

Japanese Unexamined Patent Publication No. 2006-261612 (Patent Document 1) discloses a method for manufacturing a silicon carbide semiconductor. This manufacturing method includes a preheating step for thermally decomposing a nitrogen compound gas in advance before introduction into a substrate on which silicon carbide crystals are formed.

JP 2006-261612 A

A method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure includes a step of preheating nitrogen gas before introducing nitrogen gas into a silicon carbide single crystal substrate in a reaction chamber, a carrier gas, a source gas, and nitrogen gas. And introducing a mixed gas containing ammonia gas into a heated reaction chamber to epitaxially grow a silicon carbide layer doped with nitrogen on a silicon carbide single crystal substrate.

A silicon carbide epitaxial growth apparatus according to the present disclosure includes a reaction chamber having a gas inlet, a heating mechanism for heating the reaction chamber, and a support arranged in the reaction chamber and configured to support the silicon carbide single crystal substrate. The member, a pipe configured to introduce a mixed gas containing carrier gas, raw material gas, nitrogen gas, and ammonia gas into the gas inlet, and reserve nitrogen gas upstream of the mixed gas flow from the support member A preheating mechanism configured to heat.

FIG. 1 is a schematic cross-sectional view showing the configuration of the silicon carbide epitaxial substrate according to the present embodiment. FIG. 2 is a partial cross-sectional schematic diagram showing the configuration of a film forming apparatus for executing the method for manufacturing a silicon carbide epitaxial substrate according to the present embodiment. FIG. 3 is a flowchart showing a method for manufacturing the silicon carbide epitaxial substrate according to the present embodiment. FIG. 4 is a schematic perspective view showing an example of a silicon carbide single crystal substrate. FIG. 5 is a diagram showing an example of a substrate holder for supporting a plurality of silicon carbide single crystal substrates.

[Description of Embodiment]
(1) A method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure includes a step of preheating nitrogen gas before introducing nitrogen gas into a silicon carbide single crystal substrate in a reaction chamber, a carrier gas, a source gas, Introducing a mixed gas containing nitrogen gas and ammonia gas into a heated reaction chamber to epitaxially grow a silicon carbide layer doped with nitrogen on a silicon carbide single crystal substrate.

Ammonia gas can be thermally decomposed at a lower temperature than nitrogen gas. When the ammonia gas reaches the silicon carbide single crystal substrate, the ammonia can be sufficiently thermally decomposed. Since nitrogen atoms are doped into the silicon carbide layer, with ammonia gas alone, the concentration of nitrogen atoms, which are dopants, tends to decrease toward the downstream side of the gas flow. By heating the nitrogen gas in advance, the efficiency of decomposition of the nitrogen gas in the reaction chamber can be controlled. Inside the reaction chamber, the thermal decomposition of nitrogen gas tends to proceed more downstream in the flow of nitrogen gas. By introducing a gas in which ammonia gas and nitrogen gas are mixed into the reaction chamber, the dopant concentration on the silicon carbide single crystal substrate can be made uniform. Therefore, a silicon carbide layer excellent in in-plane uniformity of doping density can be formed.

(2) The method for manufacturing a silicon carbide epitaxial substrate according to (1) further includes a step of preheating ammonia gas before introducing the ammonia gas into the reaction chamber. The temperature for preheating ammonia gas is lower than the temperature for preheating nitrogen gas.

(3) In the method for manufacturing a silicon carbide epitaxial substrate according to (1) or (2), the temperature for preheating nitrogen gas is 1000 ° C. or higher.

(4) In the method for manufacturing a silicon carbide epitaxial substrate according to any one of (1) to (3), the flow rate of nitrogen gas is larger than the flow rate of ammonia gas.

(5) In the method for manufacturing a silicon carbide epitaxial substrate according to any one of (1) to (3), the flow rate of nitrogen gas is smaller than the flow rate of ammonia gas.

(6) In the method for manufacturing a silicon carbide epitaxial substrate according to any one of (1) to (5), the diameter of the silicon carbide single crystal substrate is 100 mm or more.

(7) In the method for manufacturing a silicon carbide epitaxial substrate according to any one of (1) to (6), in the step of epitaxial growth, a plurality of silicon carbide single crystal substrates are arranged in the reaction chamber.

(8) A method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure includes a step of preheating nitrogen gas and introducing ammonia gas into the reaction chamber before introducing nitrogen gas into the silicon carbide single crystal substrate in the reaction chamber. Before, a step of preheating ammonia gas, a mixed gas containing carrier gas, source gas, nitrogen gas, and ammonia gas is introduced into the reaction chamber, and the silicon carbide layer doped with nitrogen is carbonized. And a step of epitaxial growth on the silicon single crystal substrate. The temperature for preheating ammonia gas is lower than the temperature for preheating nitrogen gas. The temperature for preheating nitrogen gas is 1000 ° C. or higher. The flow rate of nitrogen gas is larger than the flow rate of ammonia gas. The diameter of the silicon carbide single crystal substrate is 100 mm or more. In the epitaxial growth step, a plurality of silicon carbide single crystal substrates are arranged in the reaction chamber.

(9) A silicon carbide epitaxial growth apparatus according to the present disclosure is configured to support a silicon carbide single crystal substrate that is disposed in a reaction chamber having a gas inlet, a heating mechanism for heating the reaction chamber, and the reaction chamber. A support member, a pipe configured to introduce a mixed gas containing carrier gas, raw material gas, nitrogen gas and ammonia gas into the gas inlet, and upstream of the flow of the mixed gas from the support member, A first preheating mechanism configured to preheat the gas.

It is possible to heat the nitrogen gas before introducing it into the reaction chamber by the first preheating mechanism. Thereby, the efficiency of decomposition of the nitrogen gas in the reaction chamber can be controlled.

(10) The silicon carbide epitaxial growth apparatus according to (9) further includes a second preheating mechanism configured to preheat the ammonia gas upstream of the support member in the flow of the mixed gas. The temperature for preheating ammonia gas is lower than the temperature for preheating nitrogen gas.

(11) In the silicon carbide epitaxial growth apparatus according to (9) or (10), the preheating temperature of the nitrogen gas is 1000 ° C. or higher.

(12) In the silicon carbide epitaxial growth apparatus according to any one of (9) to (11), the flow rate of nitrogen gas is larger than the flow rate of ammonia gas.

(13) In the silicon carbide epitaxial growth apparatus according to any one of (9) to (11), the flow rate of nitrogen gas is smaller than the flow rate of ammonia gas.

(14) In the silicon carbide epitaxial growth apparatus according to any one of (9) to (13), the diameter of the silicon carbide single crystal substrate is 100 mm or more.

(15) In the silicon carbide epitaxial growth apparatus according to any one of (9) to (14), the support member is configured to be capable of supporting a plurality of silicon carbide single crystal substrates.

[Details of the embodiment]
Embodiments will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. In the present specification, individual planes are indicated by (), and aggregate planes are indicated by {}. As for the negative index, “−” (bar) is attached on the number in crystallography, but in this specification, a negative sign is attached before the number.

FIG. 1 is a schematic cross-sectional view showing a configuration of a silicon carbide epitaxial substrate according to the present embodiment. As shown in FIG. 1, silicon carbide epitaxial substrate 10 includes a silicon carbide single crystal substrate 20, a silicon carbide layer 31, and a silicon carbide layer 32.

Silicon carbide single crystal substrate 20 is made of, for example, polytype 4H hexagonal silicon carbide. Silicon carbide single crystal substrate 20 has a front surface 21 and a back surface 22. The maximum diameter 23 of the front surface 21 and the back surface 22 is, for example, 100 mm or more. The maximum diameter 23 may be 150 mm or more.

Silicon carbide single crystal substrate 20, silicon carbide layer 31, and silicon carbide layer 32 contain nitrogen as an n-type impurity. In one example, the concentration of n-type impurities in silicon carbide single crystal substrate 20 is higher than the concentration of n-type impurities in silicon carbide layer 31. The concentration of n-type impurities in silicon carbide layer 31 is higher than the concentration of n-type impurities in silicon carbide layer 32.

For example, the concentration of the n-type impurity in silicon carbide single crystal substrate 20 is 1 × 10 ¹⁹ cm ⁻³ . The concentration of n-type impurities in silicon carbide layer 31 is 1 × 10 ¹⁸ cm ⁻³ . The concentration of the n-type impurity of the silicon carbide layer 32 is than 2 × ¹⁰ 16 ^{cm -3} for example least 1 × ¹⁰ 15 ^{cm -3.}

The thickness of the silicon carbide single crystal substrate 20 is, for example, not less than 300 μm and not more than 600 μm. Silicon carbide layer 31 has a thickness of, for example, not less than 0.1 μm and not more than 20 μm. Silicon carbide layer 32 may have a thickness greater than that of silicon carbide layer 31. Silicon carbide layer 32 has a thickness of not less than 1 μm and not more than 150 μm, for example.

FIG. 2 is a partial cross-sectional schematic diagram showing a configuration of a film forming apparatus 40 for executing the method for manufacturing a silicon carbide epitaxial substrate according to the present embodiment. The film forming apparatus 40 is, for example, a CVD (Chemical Vapor Deposition) apparatus. As shown in FIG. 2, the film forming apparatus 40 includes a quartz tube 43, an induction heating coil 44, a heat insulating material 42, a heating element 41, a substrate holder 46, gas supply sources 51 to 55, and a pipe 61. , 62, 63, a valve 64, an exhaust pump 65, and preheating

mechanisms

71, 72.

The heating element 41 has a hollow structure and has a reaction chamber 45 formed therein. The heat insulating material 42 is disposed so as to surround the outer periphery of the heating element 41. The quartz tube 43 is disposed so as to surround the outer periphery of the heat insulating material 42. The induction heating coil 44 is provided so as to wind the outer periphery of the quartz tube 43. The heating element 41, the heat insulating material 42, and the induction heating coil 44 are elements of a heating mechanism for heating the reaction chamber 45.

The substrate holder 46 is placed inside the reaction chamber 45. Substrate holder 46 is a support member configured to hold silicon carbide single crystal substrate 20. In one example, the substrate holder 46 is a susceptor.

The gas supply source 51 supplies hydrogen (H ₂ ) gas as a carrier gas. The

gas supply sources

52 and 53 supply a source gas. The gas supply source 52 supplies a gas containing silicon (Si) atoms. The gas supply source 53 supplies a gas containing carbon (C) atoms.

The gas containing silicon atoms may be silane (SiH ₄ ) gas. Other examples of the gas containing silicon atoms include silicon tetrachloride (SiCl ₄ ) gas, trichlorosilane (SiHCl ₃ ) gas, and dichlorosilane (SiH ₂ Cl ₂ ) gas. The gas containing carbon atoms may be propane (C ₃ H ₈ ) gas.

The

gas supply sources

54 and 55 supply a gas containing nitrogen atoms as a dopant gas. The gas supply source 54 supplies nitrogen (N ₂ ) gas. The gas supply source 55 supplies ammonia (NH ₃ ) gas. In the example described below, the gas containing silicon (Si) atoms is a silane gas. The gas containing carbon atoms is propane (C ₃ H ₈ ) gas.

The pipe 61 is configured to introduce a carrier gas, a raw material gas, and a nitrogen gas into the gas inlet 47. The pipe 62 is configured to introduce ammonia gas into the gas inlet 47. The pipe 62 is connected to the pipe 61. The pipe 61 and the pipe 62 are configured to introduce a mixed gas 80 containing carrier gas, raw material gas, nitrogen gas and ammonia gas into the gas inlet 47.

The pipe 63 is connected to the gas discharge port 48 and is configured to discharge gas from the reaction chamber 45. The exhaust pump 65 is connected to the pipe 63. The valve 64 is provided in the pipe 63.

The preheating mechanism 71 is provided in the pipe 61. The preheating mechanism 72 is provided in the pipe 62. The preheating mechanism 71 can heat the nitrogen gas before the nitrogen gas is introduced into the reaction chamber 45. The preheating mechanism 72 can heat the ammonia gas before the ammonia gas is introduced into the reaction chamber 45.

Each of the preheating

mechanisms

71 and 72 may be, for example, a tube heated from the outside or a room provided with an electric heating coil inside. The preheating mechanism 71 and the preheating mechanism 72 are preferably configured so that the heating temperature can be controlled independently of each other.

The preheating mechanism 71 may be disposed upstream of the substrate holder 46 in the flow of the mixed gas 80. Therefore, the preheating mechanism 71 may be incorporated in the reaction chamber 45. The preheating mechanism 72 may be omitted.

FIG. 3 is a flowchart showing a method for manufacturing the silicon carbide epitaxial substrate according to the present embodiment. As shown in FIG. 3, first, a step (110) of preparing a silicon carbide single crystal substrate is performed. Silicon carbide single crystal substrate 20 is made of, for example, polytype 4H hexagonal silicon carbide. For example, a silicon carbide single crystal substrate 20 having a front surface 21 and a back surface 22 is prepared by slicing an ingot made of a silicon carbide single crystal manufactured by a sublimation method (see FIG. 4).

The surface 21 is a surface inclined by an off angle from the basal plane. The basal plane is, for example, a {0001} plane, specifically a (0001) Si plane. The off angle is, for example, 2 ° or more and 8 ° or less. The off direction may be the <1-100> direction or the <11-20> direction.

Next, a step (120) of forming a first silicon carbide layer (silicon carbide layer 31) is performed. As shown in FIG. 2, silicon carbide single crystal substrate 20 is arranged inside reaction chamber 45. Silicon carbide single crystal substrate 20 is supported by substrate holder 46. Hydrogen gas is supplied to the reaction chamber 45 through the pipe 61. The flow rate of hydrogen gas is, for example, 120 slm. While maintaining the state where hydrogen gas is supplied to reaction chamber 45, silicon carbide single crystal substrate 20 is heated. By causing a high frequency current to flow through the induction heating coil 44, the heating element 41 is induction heated by electromagnetic induction. Thereby, silicon carbide single crystal substrate 20 in reaction chamber 45 is heated to a temperature of about 1500 ° C. to 1700 ° C., for example.

Next, a mixed gas 80 in which hydrogen gas as a carrier gas, raw material gas, and dopant gas are mixed is introduced into the reaction chamber 45. The dopant gas may be either ammonia gas or nitrogen gas, or both. When the dopant gas contains nitrogen gas, the nitrogen gas is heated by the preheating mechanism 71. The heating temperature of nitrogen gas is 1000 ° C. or higher. Inside reaction chamber 45, silicon carbide layer 31 is formed on silicon carbide single crystal substrate 20 by epitaxial growth.

Subsequently, a step (130) of forming a second silicon carbide layer (silicon carbide layer 32) is performed. Similar to step 120, the mixed gas 80 is introduced into the reaction chamber 45. The mixed gas 80 includes ammonia gas and nitrogen gas as dopant gases. The preheating mechanism 71 heats nitrogen gas. In this embodiment, the heating temperature is 1000 ° C. or higher.

Furthermore, the ammonia gas may be preheated by the preheating mechanism 72. Ammonia gas undergoes thermal decomposition from a lower temperature than nitrogen gas. In this embodiment, when the ammonia gas is preheated, the ammonia gas preheating temperature may be lower than the nitrogen gas preheating temperature.

As described above, silicon carbide layer 32 is formed on silicon carbide layer 31 by epitaxial growth.

In order to improve the yield of a device (for example, a high breakdown voltage device) formed on a silicon carbide epitaxial substrate, it is desirable that the nitrogen atom doping density is uniformly distributed in the plane of the substrate. When the ammonia gas reaches the silicon carbide single crystal substrate 20, the ammonia can be sufficiently thermally decomposed. By doping the silicon carbide layer with nitrogen atoms, the concentration of the dopant (nitrogen atoms) decreases toward the downstream side of the ammonia gas flow. When the dopant gas is only ammonia gas, the doping density tends to vary within the substrate plane as the silicon carbide single crystal substrate 20 has a larger diameter. In other words, the in-plane uniformity of the doping density tends to decrease.

On the other hand, nitrogen gas has lower thermal decomposition efficiency than ammonia gas because of the large energy of triple bonds of nitrogen molecules. For this reason, it is considered that the thermal decomposition of the nitrogen gas is more likely to proceed toward the downstream of the nitrogen gas flow inside the reaction chamber 45.

In the present embodiment, a mixed gas of nitrogen gas and ammonia gas is used as the dopant gas. Further, the nitrogen gas is heated before being introduced into the reaction chamber. Thereby, the efficiency of decomposition of nitrogen gas in the reaction chamber can be controlled. Inside the reaction chamber, the thermal decomposition of nitrogen gas tends to proceed more downstream in the flow of nitrogen gas. By introducing a gas in which ammonia gas and nitrogen gas are mixed into the reaction chamber, the dopant concentration on the silicon carbide single crystal substrate can be made uniform. Therefore, a silicon carbide layer excellent in in-plane uniformity of the doping density distribution can be formed.

According to the method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure, in-plane uniformity of the doping density can be improved even when silicon carbide is epitaxially grown in a reaction chamber having a large volume. Therefore, in-plane uniformity of doping density can be improved in a silicon carbide epitaxial substrate having a large diameter (for example, a diameter of 150 mm or more).

An example in which a silicon carbide layer 32 having a doping density of 5 × 10 ¹⁵ (cm ⁻³ ) in a silicon carbide single crystal substrate having a diameter of 150 mm is formed by epitaxial growth according to the present disclosure will be described below. In this example, the temperature for preheating nitrogen gas is 1000 ° C. The flow rate of nitrogen gas is 3 sccm. The flow rate of ammonia gas is 1 sccm. The flow rate of hydrogen gas is 120 slm. The flow rate of silane gas is 46 sccm. The flow rate of propane gas is 17 sccm.

In the above example, the flow rate of nitrogen gas is larger than the flow rate of ammonia gas. However, the flow rate of nitrogen gas can be smaller than the flow rate of ammonia gas. In other words, the ratio of the flow rate of nitrogen gas to the flow rate of ammonia gas (the value obtained by dividing the flow rate of nitrogen gas by the flow rate of ammonia gas) may be greater than 1 or less than 1.

In the above example, a silicon carbide single crystal substrate having a diameter of 150 mm is shown. Even when the method for manufacturing a silicon carbide epitaxial substrate according to the present embodiment is applied to a silicon carbide single crystal substrate having a small diameter, in-plane uniformity of doping density can be improved. The diameter of the silicon carbide single crystal substrate may be 100 mm or more.

Furthermore, according to the present embodiment, even when a plurality of silicon carbide single crystal substrates are arranged in the reaction chamber, the in-plane uniformity of the doping density can be improved in each silicon carbide single crystal substrate. it can.

FIG. 5 is a diagram showing an example of a substrate holder 46 for supporting a plurality of silicon carbide single crystal substrates 20. As shown in FIG. 5, for example, two silicon carbide single crystal substrates 20 are arranged on substrate holder 46. Inside the reaction chamber 45, the substrate holder 46 may rotate about the central axis 49. The diameter of silicon carbide single crystal substrate 20 may be 100 mm or more, or 150 mm or more.

It should be considered that the embodiment disclosed this time is illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include meanings equivalent to the scope of claims and all modifications within the scope.

10 silicon carbide epitaxial substrate, 20 silicon carbide single crystal substrate, 21 front surface, 22 back surface, 23 maximum diameter, 31, 32 silicon carbide layer, 40 film forming device, 41 heating element, 42 heat insulating material, 43 quartz tube, 44 induction heating Coil, 45 reaction chamber, 46 substrate holder, 47 gas inlet, 48 gas outlet, 49 central axis, 51-55 gas supply source, 61-63 piping, 64 valve, 65 exhaust pump, 71, 72 preheating mechanism, 80 gas mixture, 110-130 steps.

Claims

A step of preheating the nitrogen gas before introducing the nitrogen gas into the silicon carbide single crystal substrate in the reaction chamber;
Introducing a mixed gas containing a carrier gas, a source gas, the nitrogen gas, and ammonia gas into the reaction chamber, and epitaxially growing a silicon carbide layer doped with nitrogen on the silicon carbide single crystal substrate; A method for manufacturing a silicon carbide epitaxial substrate.
A step of preheating the ammonia gas before introducing the ammonia gas into the reaction chamber;
The method for manufacturing a silicon carbide epitaxial substrate according to claim 1, wherein a temperature of the ammonia gas preheating is lower than a temperature of the nitrogen gas preheating.
3. The method for manufacturing a silicon carbide epitaxial substrate according to claim 1, wherein a temperature of preheating the nitrogen gas is 1000 ° C. or higher.
The method for manufacturing a silicon carbide epitaxial substrate according to any one of claims 1 to 3, wherein a flow rate of the nitrogen gas is larger than a flow rate of the ammonia gas.
The method for manufacturing a silicon carbide epitaxial substrate according to any one of claims 1 to 3, wherein a flow rate of the nitrogen gas is smaller than a flow rate of the ammonia gas.
The method for manufacturing a silicon carbide epitaxial substrate according to any one of claims 1 to 5, wherein the silicon carbide single crystal substrate has a diameter of 100 mm or more.
The method for manufacturing a silicon carbide epitaxial substrate according to any one of claims 1 to 6, wherein in the epitaxial growth step, a plurality of the silicon carbide single crystal substrates are arranged in the reaction chamber.
A step of preheating the nitrogen gas before introducing the nitrogen gas into the silicon carbide single crystal substrate in the reaction chamber;
A step of preheating the ammonia gas before introducing the ammonia gas into the reaction chamber;
Introducing a mixed gas containing a carrier gas, a source gas, the nitrogen gas, and ammonia gas into the reaction chamber, and epitaxially growing a silicon carbide layer doped with nitrogen on the silicon carbide single crystal substrate; And
The preheating temperature of the ammonia gas is lower than the preheating temperature of the nitrogen gas,
The temperature of the nitrogen gas preheating is 1000 ° C. or higher,
The flow rate of the nitrogen gas is larger than the flow rate of the ammonia gas,
The diameter of the silicon carbide single crystal substrate is 100 mm or more,
A method for manufacturing a silicon carbide epitaxial substrate, wherein in the epitaxial growth step, a plurality of the silicon carbide single crystal substrates are arranged in the reaction chamber.
A reaction chamber having a gas inlet;
A heating mechanism for heating the reaction chamber;
A support member disposed within the reaction chamber and configured to support a silicon carbide single crystal substrate;
A pipe configured to introduce a mixed gas containing carrier gas, source gas, nitrogen gas and ammonia gas into the gas inlet;
A silicon carbide epitaxial growth apparatus comprising: a first preheating mechanism configured to preheat the nitrogen gas upstream of the support member in the mixed gas flow.
A second preheating mechanism configured to preheat the ammonia gas upstream of the support member in the mixed gas flow;
The silicon carbide epitaxial growth apparatus according to claim 9, wherein a temperature of the ammonia gas preheating is lower than a temperature of the nitrogen gas preheating.
The silicon carbide epitaxial growth apparatus according to claim 9 or 10, wherein a temperature of the nitrogen gas preheating is 1000 ° C or higher.
The silicon carbide epitaxial growth apparatus according to any one of claims 9 to 11, wherein a flow rate of the nitrogen gas is larger than a flow rate of the ammonia gas.
The silicon carbide epitaxial growth apparatus according to any one of claims 9 to 11, wherein a flow rate of the nitrogen gas is smaller than a flow rate of the ammonia gas.
The silicon carbide epitaxial growth apparatus according to any one of claims 9 to 13, wherein the support member is configured to be capable of supporting the silicon carbide single crystal substrate having a diameter of 100 mm or more.
The silicon carbide epitaxial growth apparatus according to any one of claims 9 to 14, wherein the support member is configured to be capable of supporting a plurality of the silicon carbide single crystal substrates.