Manufacturing method of silicon carbide epitaxial substrate and manufacturing method of silicon carbide semiconductor device

Abstract

To provide a manufacturing method of a silicon carbide epitaxial substrate capable of improving a yield of a silicon carbide semiconductor device, and a manufacturing method of the silicon carbide semiconductor device.SOLUTION: A manufacturing method of a silicon carbide epitaxial substrate has the steps of: arranging a silicon carbide substrate in a transportation stand-by chamber; transporting the silicon carbide substrate to a growth chamber from the transportation stand-by chamber; and forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber. In a step of transporting the silicon carbide substrate from the transportation stand-by chamber to the growth chamber, a temperature of the growth chamber is 300°C or more and a transportation of the silicon carbide substrate is temporarily stopped in a state where at least a part of the silicon carbide substrate is entered in the growth chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a silicon carbide epitaxial substrate and a method for manufacturing a silicon carbide semiconductor device. [Background technology]

[0002] Japanese Patent Application Laid-Open No. 2017-145150 (Patent Document 1) describes a method for manufacturing a silicon carbide epitaxial substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-145150 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a method for manufacturing a silicon carbide epitaxial substrate and a method for manufacturing a silicon carbide semiconductor device that can improve the yield of silicon carbide semiconductor devices. [Means for solving the problem]

[0005] A method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure includes the following steps: placing a silicon carbide substrate in a transfer standby chamber; transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber; forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber; transferring the silicon carbide substrate from the transfer standby chamber to the growth chamber, the temperature of the growth chamber is 300°C or higher, and transferring the silicon carbide substrate is temporarily stopped with at least a portion of the silicon carbide substrate in the growth chamber; thereby preventing silicon carbide foreign matter from falling onto the silicon carbide substrate; and consequently improving the yield of silicon carbide semiconductor devices. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to provide a method for manufacturing a silicon carbide epitaxial substrate and a method for manufacturing a silicon carbide semiconductor device that can improve the yield of silicon carbide semiconductor devices. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view schematically illustrating the configuration of a silicon carbide substrate. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a cross-sectional view schematically illustrating the configuration of an apparatus for manufacturing a silicon carbide epitaxial substrate according to this embodiment. [Figure 4] FIG. 4 is a flow diagram illustrating a method for manufacturing a silicon carbide epitaxial substrate according to this embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view showing a step of transferring the silicon carbide substrate to a growth chamber. [Figure 6] FIG. 6 is a diagram showing a first example of the relationship between the transport speed of the silicon carbide substrate and time. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a state in which the holder is placed on the stage. [Figure 8] FIG. 8 is a cross-sectional view schematically illustrating the configuration of a silicon carbide epitaxial substrate. [Figure 9] FIG. 9 is a diagram showing a second example of the relationship between the transport speed of the silicon carbide substrate and time. [Figure 10] FIG. 10 is a diagram showing a third example of the relationship between the transport speed of the silicon carbide substrate and time. [Figure 11] FIG. 11 is a cross-sectional view schematically showing the configuration of a silicon carbide semiconductor device in accordance with this embodiment. [Figure 12] FIG. 12 is a schematic view illustrating the method for manufacturing a silicon carbide semiconductor device according to this embodiment. [Figure 13] FIG. 13 is a schematic cross-sectional view showing a step of forming a body region. [Figure 14]FIG. 14 is a schematic cross-sectional view showing a step of forming a source region. [Figure 15] FIG. 15 is a cross-sectional view schematically illustrating a step of forming a trench in first main surface 1. As shown in FIG. [Figure 16] FIG. 16 is a cross-sectional view showing a process of forming a gate insulating film. [Figure 17] FIG. 17 is a cross-sectional view showing a process of forming a gate electrode and an interlayer insulating film. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Summary of the embodiments of the present disclosure] First, an overview of the embodiments of the present disclosure will be described. In the crystallographic descriptions in this specification, individual orientations are represented by [ ], collective orientations by < >, individual planes by ( ), and collective planes by {}. A negative crystallographic index is usually represented by placing a "-" (bar) above the number, but in this specification, a negative crystallographic index is represented by placing a negative sign before the number.

[0009] (1) A method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure includes the following steps: placing a silicon carbide substrate in a transfer standby chamber; transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber; and forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber. In the step of transferring the silicon carbide substrate from the transfer standby chamber to the growth chamber, the temperature of the growth chamber is 300°C or higher, and transfer of the silicon carbide substrate is temporarily stopped with at least a portion of the silicon carbide substrate in the growth chamber. This makes it possible to prevent silicon carbide foreign matter from falling onto the silicon carbide substrate. As a result, the yield of silicon carbide semiconductor devices can be improved.

[0010] (2) In the method for manufacturing a silicon carbide epitaxial substrate according to (1), the growth chamber may include a thermal insulator. Transfer of the silicon carbide substrate may be temporarily stopped before the silicon carbide substrate enters the space surrounded by the thermal insulator.

[0011] (3) A method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure includes the following steps: placing a silicon carbide substrate in a transfer standby chamber; transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber; forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber; in the step of transferring the silicon carbide substrate from the transfer standby chamber to the growth chamber, the temperature of the growth chamber is 300°C or higher; and in the step of placing the silicon carbide substrate in the transfer standby chamber, the temperature of the transfer standby chamber is 10°C or higher.

[0012] (4) According to the method for manufacturing a silicon carbide epitaxial substrate according to (3) above, in the step of placing the silicon carbide substrate in the transfer standby chamber, the temperature of the transfer standby chamber may be 300° C. or higher.

[0013] (5) A method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure includes the following steps: placing a silicon carbide substrate in a transfer standby chamber; transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber; and forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber. In the step of transferring the silicon carbide substrate from the transfer standby chamber to the growth chamber, the temperature of the growth chamber is 300°C or higher, and the transfer speed of the silicon carbide substrate is 200 mm / sec or less.

[0014] (6) A method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure includes the following steps: placing a silicon carbide substrate in a transfer standby chamber; transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber; forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber; in the step of transferring the silicon carbide substrate from the transfer standby chamber to the growth chamber, the temperature of the growth chamber is 300°C or higher, and the silicon carbide substrate is transferred at a first transfer speed and then at a second transfer speed slower than the first transfer speed; the first transfer speed is 200 mm / sec or less.

[0015] (7) In the method for manufacturing a silicon carbide epitaxial substrate according to (6) above, the second transport speed may be 100 mm / sec or less.

[0016] (8) In the method for manufacturing a silicon carbide epitaxial substrate according to any one of (1) to (7), the growth chamber may have a heating element, and the silicon carbide substrate may be disposed inside the heating element.

[0017] (9) In the method for manufacturing a silicon carbide epitaxial substrate according to any one of (1) to (8) above, in the step of transferring the silicon carbide substrate from the transfer standby chamber to the growth chamber, the temperature of the growth chamber may be 500° C. or higher.

[0018] (10) According to the method for manufacturing a silicon carbide epitaxial substrate according to any one of (1) to (9) above, in the step of transferring the silicon carbide substrate from the transfer standby chamber to the growth chamber, the temperature of the growth chamber may be 1200° C. or less.

[0019] (11) A method for manufacturing a silicon carbide semiconductor device according to the present disclosure includes the following steps: A silicon carbide epitaxial substrate is manufactured by the method for manufacturing a silicon carbide epitaxial substrate according to any one of (1) to (10) above; and an electrode is formed on the silicon carbide epitaxial substrate.

[0020] [Details of the embodiments of the present disclosure] Hereinafter, the details of the embodiments of the present disclosure will be described. In the following description, the same or corresponding elements will be denoted by the same reference numerals, and the same description thereof will not be repeated.

[0021] (First embodiment) A method for manufacturing a silicon carbide epitaxial substrate 100 according to the first embodiment will be described. First, a silicon carbide substrate 10 is prepared. FIG. 1 is a plan view schematically showing the configuration of silicon carbide substrate 10. FIG. 2 is a cross-sectional view schematically showing the configuration of silicon carbide substrate 10 taken along line II-II in FIG. 1. As shown in FIGS. 1 and 2, silicon carbide substrate 10 has a third main surface 15 and a second main surface 2. The second main surface 2 is located opposite to the third main surface 15.

[0022] As shown in FIG. 1, silicon carbide substrate 10 has an outer peripheral edge 5. Outer peripheral edge 5 has, for example, an orientation flat 3 and an arc-shaped portion 4. Orientation flat 3 extends along first direction 101. As shown in FIG. 1, orientation flat 3 is linear when viewed along a straight line perpendicular to third main surface 15 (hereinafter also referred to as a plan view). Arc-shaped portion 4 is continuous with orientation flat 3. Arc-shaped portion 4 is arc-shaped in a plan view.

[0023] 1, in a plan view, the third main surface 15 extends along each of a first direction 101 and a second direction 102. In a plan view, the first direction 101 is a direction perpendicular to the second direction 102.

[0024] The first direction 101 is, for example, the <11-20> direction. The first direction 101 may be, for example, the [11-20] direction. The first direction 101 may be a direction obtained by projecting the <11-20> direction onto the first main surface 1. From another perspective, the first direction 101 may be, for example, a direction including a <11-20> direction component.

[0025] The second direction 102 is, for example, the <1-100> direction. The second direction 102 may be, for example, the [1-100] direction. The second direction 102 may be, for example, a direction obtained by projecting the <1-100> direction onto the first main surface 1. From another perspective, the second direction 102 may be, for example, a direction including a <1-100> direction component.

[0026] The third main surface 15 may be a surface inclined with respect to the {0001} plane. When the third main surface 15 is inclined with respect to the {0001} plane, the inclination angle (off angle) with respect to the {0001} plane is, for example, 2° or more and 6° or less. When the third main surface 15 is inclined with respect to the {0001} plane, the inclination direction (off direction) of the third main surface 15 is, for example, the <11-20> direction. From another perspective, the first direction 101 may be the off direction of the third main surface 15.

[0027] As shown in FIG. 1, the maximum diameter W1 of the third main surface 15 is, for example, 100 mm (4 inches). The maximum diameter W1 may be 125 mm (5 inches) or more, or 150 mm (6 inches) or more. There is no particular upper limit to the maximum diameter W1. The maximum diameter W1 may be, for example, 200 mm (8 inches) or less. In a plan view, the maximum diameter W1 is the maximum distance between any two points on the outer circumferential edge 5.

[0028] In this specification, 4 inches refers to 100 mm or 101.6 mm (4 inches x 25.4 mm / inch). 6 inches refers to 150 mm or 152.4 mm (6 inches x 25.4 mm / inch). 8 inches refers to 200 mm or 203.2 mm (8 inches x 25.4 mm / inch).

[0029] The polytype of silicon carbide constituting silicon carbide substrate 10 is, for example, 4H. Silicon carbide substrate 10 contains nitrogen (N) as an n-type impurity. Silicon carbide substrate 10 has an n-type conductivity. Third direction 103 is a direction from third main surface 15 toward second main surface 2. Third direction 103 is perpendicular to each of first direction 101 and second direction 102.

[0030] (Silicon carbide epitaxial substrate manufacturing equipment) 3 is a cross-sectional view schematically illustrating the configuration of an apparatus for manufacturing silicon carbide epitaxial substrate 100 according to this embodiment. As shown in FIG. 3, apparatus 250 for manufacturing silicon carbide epitaxial substrate 100 is, for example, a hot-wall horizontal CVD (Chemical Vapor Deposition) apparatus. Apparatus 250 for manufacturing silicon carbide epitaxial substrate 100 includes a transfer standby chamber 251, a growth chamber 252, a gate valve 264, and a gas supply nozzle (not shown). Gate valve 264 is disposed between transfer standby chamber 251 and growth chamber 252.

[0031] The transfer standby chamber 251 has a storage section 261 and a transfer robot arm 262. The transfer robot arm 262 is disposed inside the storage section 261. The growth chamber 252 has a quartz tube 204, a liner tube 201, a heat insulating material 202, a heating element 203, a susceptor 206, a rotating shaft 209, and an induction heating coil (not shown).

[0032] The liner tube 201 is disposed inside the quartz tube 204. The liner tube 201 is made of, for example, quartz. The liner tube 201 is disposed downstream of the gas supply nozzle.

[0033] Susceptor 206 is disposed in a space surrounded by the inner wall surface of heating element 203. Susceptor 206 is rotatably supported by rotation shaft 209. On susceptor 206, a holder 210 is disposed, on which silicon carbide substrate 10 is disposed.

[0034] The heat insulating material 202 has, for example, a rectangular cylindrical shape. The heat insulating material 202 is disposed inside the quartz tube 204. The heat insulating material 202 is disposed downstream of the liner tube 201. The heating element 203 has, for example, a rectangular cylindrical shape. The heating element 203 is made of, for example, graphite. The heating element 203 is disposed downstream of the liner tube 201.

[0035] The heat insulating material 202 surrounds the outer periphery of the heating element 203. The induction heating coil is wound around the outer periphery of, for example, a quartz tube 204. The induction heating coil is configured so that an alternating current can be supplied from an external power source (not shown). This causes induction heating of the heating element 203. As a result, the heating element 203 generates heat. The heating element 203 may also be heated by, for example, a resistance heating method.

[0036] (Method for manufacturing silicon carbide epitaxial substrate) Next, a method for manufacturing silicon carbide epitaxial substrate 100 in accordance with this embodiment will be described.

[0037] Fig. 4 is a flow diagram illustrating a method for manufacturing a silicon carbide epitaxial substrate 100 according to this embodiment. As shown in Fig. 4, the method for manufacturing a silicon carbide epitaxial substrate 100 according to this embodiment mainly includes a step (S10) of placing a silicon carbide substrate 10 in a transfer standby chamber 251, a step (S20) of transferring the silicon carbide substrate 10 to a growth chamber 252, and a step (S30) of forming a silicon carbide epitaxial layer on the silicon carbide substrate 10.

[0038] First, a silicon carbide substrate 10 is prepared. A silicon carbide single crystal of polytype 4H is manufactured by, for example, sublimation. Next, the silicon carbide single crystal is sliced ​​by, for example, a wire saw, to prepare the silicon carbide substrate 10. The silicon carbide substrate 10 contains an n-type impurity such as nitrogen. The conductivity type of the silicon carbide substrate 10 is, for example, n-type. Next, the silicon carbide substrate 10 is mechanically polished. Next, the silicon carbide substrate 10 is subjected to chemical mechanical polishing.

[0039] Next, a step (S10) of arranging the silicon carbide substrate 10 in the transfer standby chamber 251 is performed. As shown in FIG. 3 , the silicon carbide substrate 10 is arranged on the holder 210. The holder 210 is placed on the transfer robot arm 262. The transfer robot arm 262 supports the holder 210. The silicon carbide substrate 10 may be arranged on the holder 210 outside the transfer standby chamber 251, and then the holder 210 on which the silicon carbide substrate 10 is arranged may be arranged in the transfer standby chamber 251. As another aspect, the holder 210 may be arranged in the transfer standby chamber 251 first, and then the silicon carbide substrate 10 may be arranged on the holder 210. In the step (S10) of arranging the silicon carbide substrate 10 in the transfer standby chamber 251, the gate valve 264 is closed.

[0040] Next, a step (S20) of transferring silicon carbide substrate 10 to growth chamber 252 is performed. FIG. 5 is a cross-sectional view schematically illustrating the step of transferring silicon carbide substrate 10 to growth chamber 252. As shown in FIG. 5, holder 210 on which silicon carbide substrate 10 is placed is transferred from transfer standby chamber 251 to growth chamber 252 by transfer robot arm 262. Transfer robot arm 262 extends from transfer standby chamber 251 toward growth chamber 252. Thereby, silicon carbide substrate 10 is transferred from transfer standby chamber 251 to growth chamber 252. While silicon carbide substrate 10 is being transferred from transfer standby chamber 251 to growth chamber 252, gate valve 264 is open. After passing through gate valve 264, silicon carbide substrate 10 enters inside liner pipe 201.

[0041] In the step (S20) of transferring silicon carbide substrate 10 to growth chamber 252, the temperature of growth chamber 252 is 300°C or higher. Specifically, the temperature of growth chamber 252 is the temperature of heating element 203 disposed in growth chamber 252. The temperature of growth chamber 252 may be 500°C or higher, 600°C or higher, 700°C or higher, 800°C or higher, or 900°C or higher. The temperature of growth chamber 252 may be 1200°C or lower, 1100°C or lower, or 1000°C or lower.

[0042] In the step (S20) of transporting the silicon carbide substrate 10 to the growth chamber 252, the transport of the silicon carbide substrate 10 is temporarily stopped with at least a portion of the silicon carbide substrate 10 inside the growth chamber 252. For example, the transport of the silicon carbide substrate 10 may be temporarily stopped before the silicon carbide substrate 10 enters the space surrounded by the heat insulating material 202. In this case, the front end (the portion on the most downstream side) of the holder 210 is located inside the liner pipe 201. The rear end (the portion on the most upstream side) of the holder 210 may be located in the transport standby chamber 251 or in the growth chamber 252. This causes the temperatures of the holder 210 and the silicon carbide substrate 10 to gradually increase.

[0043] FIG. 6 is a diagram showing a first example relationship between the transport speed of the silicon carbide substrate 10 and time. At a first point in time T1, the holder 210 is located in the transport standby chamber 251. From the first point in time T1 to a second point in time T2, the transport speed of the silicon carbide substrate 10 increases. From the second point in time T2 to a third point in time T3, the transport speed of the silicon carbide substrate 10 (first transport speed A1) is constant. At the first point in time T1, the front end of the holder 210 is located in the transport standby chamber 251. From the third point in time T3 to a fourth point in time T4, the transport speed of the silicon carbide substrate 10 decreases. At the fourth point in time T4, the transport of the silicon carbide substrate 10 temporarily stops. At the fourth point in time T4, the front end of the holder 210 is located in the growth chamber 252. From the fourth point in time T4 to a fifth point in time T5, the silicon carbide substrate 10 is stationary. The time during which the transfer of silicon carbide substrate 10 is stopped (the time from fourth point in time T4 to fifth point in time T5) is, for example, not less than 3 minutes and not more than 30 minutes.

[0044] Between the fifth point in time T5 and the sixth point in time T6, the transport speed of the silicon carbide substrate 10 increases. Between the sixth point in time T6 and the seventh point in time T7, the transport speed of the silicon carbide substrate 10 is constant. Between the seventh point in time T7 and the eighth point in time T8, the transport speed of the silicon carbide substrate 10 decreases. At any point in time between the fifth point in time T5 and the eighth point in time T8, at least a part of the holder 210 enters the area surrounded by the heat insulating material 202. The transport speed of the silicon carbide substrate 10 between the sixth point in time T6 and the seventh point in time T7 may be the same as or different from the transport speed of the silicon carbide substrate 10 between the second point in time T2 and the third point in time T3.

[0045] 7 is a cross-sectional schematic view showing a state in which holder 210 is placed on susceptor 206. After holder 210 on which silicon carbide substrate 10 is placed enters the area surrounded by heat insulating material 202, holder 210 on which silicon carbide substrate 10 is placed is placed on susceptor 206. As shown in FIG. 7, holder 210 is placed in the area surrounded by heating element 203. After holder 210 is placed on susceptor 206, transfer robot arm 262 passes through gate valve 264 and returns to transfer standby chamber 251. After transfer robot arm 262 passes through gate valve 264, gate valve 264 is closed.

[0046] Next, a step (S30) of forming a silicon carbide epitaxial layer on silicon carbide substrate 10 is performed. Specifically, silicon carbide epitaxial layer 20 is formed by epitaxial growth on silicon carbide substrate 10 by a CVD (Chemical Vapor Deposition) method. First, the temperature of growth chamber 252 is increased from the standby temperature to the growth temperature. The standby temperature is, for example, 900°C. The growth temperature is, for example, 1400°C or higher and 1700°C or lower. In the epitaxial growth, for example, silane (SiH4) and propane (C3H8) are used as source gases, and hydrogen (H2) is used as a carrier gas. In the epitaxial growth, for example, ammonia is used as a dopant gas. As a result, nitrogen atoms are introduced into silicon carbide epitaxial layer 20.

[0047] Specifically, a carrier gas is introduced into the growth chamber 252 from a gas supply nozzle. Next, ammonia silane and propane are introduced into the growth chamber 252. The flow rate of the carrier gas is, for example, 100 slm. The flow rate of silane is, for example, 46 sccm. The flow rate of propane is, for example, 29 sccm. The flow rate of ammonia gas is, for example, 1.5 sccm. The pressure inside the growth chamber 252 is, for example, not less than 2 kPa and not more than 6 kPa. As described above, in the growth chamber 252, a silicon carbide epitaxial layer 20 is formed on the silicon carbide substrate 10.

[0048] 8 is a cross-sectional schematic diagram showing the configuration of a silicon carbide epitaxial substrate. As shown in FIG. 8, silicon carbide epitaxial substrate 100 has silicon carbide substrate 10 and silicon carbide epitaxial layer 20. Silicon carbide epitaxial layer 20 has buffer layer 11 and drift layer 14. Buffer layer 11 is provided on third main surface 15. Drift layer 14 is provided on buffer layer 11. Each of buffer layer 11 and drift layer 14 contains an n-type impurity such as nitrogen. The impurity concentration of buffer layer 11 may be higher than the impurity concentration of drift layer 14.

[0049] (Second embodiment) Next, a method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the second embodiment will be described.

[0050] The method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the second embodiment differs from the method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the first embodiment mainly in the configuration in which the temperature of transfer standby chamber 251 is 10° C. or higher, but is substantially the same as the method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the first embodiment in other configurations. The following description will focus on the configurations that differ from the method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the first embodiment.

[0051] The transfer standby chamber 251 has, for example, a heating mechanism (not shown). The heating mechanism can heat the inside of the transfer standby chamber 251. In the step of placing the silicon carbide substrate 10 in the transfer standby chamber 251, the temperature of the transfer standby chamber 251 is, for example, 10°C or higher. The temperature of the transfer standby chamber 251 may be 150°C or higher, 300°C or higher, 500°C or higher, or 700°C or higher. The temperature of the transfer standby chamber 251 may be, for example, 900°C or lower, 700°C or lower, or 500°C or lower.

[0052] The temperature of the transport standby chamber 251 is, for example, 10° C. or higher before the silicon carbide substrate 10 is placed in the transport standby chamber 251. In another aspect, the temperature of the transport standby chamber 251 may be lower than 50° C. before the silicon carbide substrate 10 is placed in the transport standby chamber 251, and may be heated to a temperature of 50° C. or higher after the silicon carbide substrate 10 is placed in the transport standby chamber 251.

[0053] In the step (S20) of transferring silicon carbide substrate 10 to growth chamber 252, it is desirable that the difference in temperature between transfer standby chamber 251 and growth chamber 252 is small. The difference in temperature between transfer standby chamber 251 and growth chamber 252 may be, for example, 500°C or less, 300°C or less, or 100°C or less. The temperature of transfer standby chamber 251 may be lower than, the same as, or higher than the temperature of growth chamber 252.

[0054] In the method for manufacturing silicon carbide epitaxial substrate 100 according to the second embodiment, the transport of silicon carbide substrate 10 may or may not be temporarily stopped when at least a portion of silicon carbide substrate 10 is in growth chamber 252.

[0055] (Third embodiment) Next, a method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the third embodiment will be described.

[0056] The method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the third embodiment differs from the method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the first embodiment mainly in that the transfer speed is slow, but in other respects the method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the first embodiment is substantially the same. The following description will focus on the differences from the method for manufacturing silicon carbide epitaxial substrate 100 in accordance with the first embodiment.

[0057] 9 is a diagram showing a second example of the relationship between the transport speed of silicon carbide substrate 10 and time. At first point in time T1, holder 210 is located in transport standby chamber 251. From first point in time T1 to second point in time T2, the transport speed of silicon carbide substrate 10 increases. From second point in time T2 to third point in time T3, the transport speed of silicon carbide substrate 10 (third transport speed A3) is constant. At second point in time T2, the front end of holder 210 is located in transport standby chamber 251. At third point in time T3, the front end of holder 210 is located in growth chamber 252. From third point in time T3 to fourth point in time T4, the transport speed of silicon carbide substrate 10 decreases. At any point in time between second point in time T2 and third point in time T3, at least a part of holder 210 enters the area surrounded by heat insulating material 202. The transport speed (third transport speed A3) of silicon carbide substrate 10 is 200 mm / sec or less. Third transport speed A3 may be 150 mm / sec or less, 100 mm / sec or less, or 50 mm / sec or less. Third transport speed A3 may be 10 mm / sec or more, or 20 mm / sec or more.

[0058] 10 is a diagram showing a third example of the relationship between the transport speed of the silicon carbide substrate 10 and time. At a first point in time T1, the holder 210 is located in the transport standby chamber 251. From the first point in time T1 to a second point in time T2, the transport speed of the silicon carbide substrate 10 increases. From the second point in time T2 to a third point in time T3, the transport speed of the silicon carbide substrate 10 (first transport speed A1) is constant. At the second point in time T2, the front end of the holder 210 may be located in the transport standby chamber 251. At the third point in time T3, the front end of the holder 210 may be located in the transport standby chamber 251 or in the growth chamber 252. From the third point in time T3 to a fourth point in time T4, the transport speed of the silicon carbide substrate 10 decreases.

[0059] Between fourth point in time T4 and fifth point in time T5, the transport speed of silicon carbide substrate 10 (second transport speed A2) is constant. Between fifth point in time T5 and sixth point in time T6, the transport speed of silicon carbide substrate 10 decreases. At any time between fourth point in time T4 and sixth point in time T6, at least a part of holder 210 enters the area surrounded by heat insulating material 202. Second transport speed A2 is slower than first transport speed A1. That is, silicon carbide substrate 10 is transported at first transport speed A1, and then at second transport speed A2 slower than first transport speed A1. First transport speed A1 is, for example, 200 mm / sec or less. Second transport speed A2 is, for example, 100 mm / sec or less. Second transport speed A2 may be 80 mm / sec or less, 50 mm / sec or less, or 30 mm / sec or less. The second conveying speed A2 may be 5 mm / sec or more, or may be 10 mm / sec or more.

[0060] (Silicon carbide semiconductor device) Next, the configuration of a silicon carbide semiconductor device 300 according to this embodiment will be described. FIG. 11 is a cross-sectional schematic diagram showing the configuration of the silicon carbide semiconductor device 300 according to this embodiment. As shown in FIG. 11 , the silicon carbide semiconductor device 300 according to this embodiment mainly includes a silicon carbide epitaxial substrate 100, a gate insulating film 115, a gate electrode 127, a source electrode 116, a drain electrode 120, a source wiring 119, and an interlayer insulating film 126. The silicon carbide epitaxial substrate 100 includes a silicon carbide substrate 10, a silicon carbide epitaxial layer 20, a first main surface 1, and a second main surface 2. The silicon carbide epitaxial layer 20 includes a buffer layer 11, a drift layer 14, a body region 113, a source region 114, and a contact region 118.

[0061] The body region 113 is formed on the drift layer 14. The body region 113 is in contact with the drift layer 14. The body region 113 contains p-type impurities such as aluminum. The body region 113 has p-type conductivity. The source region 114 is formed on the body region 113. The source region 114 contains n-type impurities such as phosphorus. The source region 114 has n-type conductivity. The concentration of the n-type impurities contained in the source region 114 may be higher than the concentration of the p-type impurities contained in the body region 113.

[0062] The contact region 118 penetrates the source region 114 and the body region 113. The contact region 118 is in contact with each of the source region 114, the body region 113, and the drift layer 14. The contact region 118 contains p-type impurities such as aluminum. The concentration of the p-type impurities contained in the contact region 118 may be higher than the concentration of the n-type impurities contained in the source region 114.

[0063] A trench 106 is provided in the first main surface 1. The trench 106 is defined by a side surface 123 and a bottom surface 124. The side surface 123 is formed by the source region 114, the body region 113, and the drift layer 14. The bottom surface 124 is formed by the drift layer 14.

[0064] The gate insulating film 115 is in contact with the drift layer 14 at its bottom surface 124, and is in contact with each of the drift layer 14, the body region 113, and the source region 114 at its side surface 123. The gate electrode 127 is disposed on the gate insulating film 115. The gate electrode 127 is in contact with the gate insulating film 115 inside the trench 106. The gate electrode 127 faces each of the side surface 123 and the bottom surface 124 of the trench 106.

[0065] The interlayer insulating film 126 covers the gate electrode 127. The interlayer insulating film 126 is in contact with the gate insulating film 115. The interlayer insulating film 126 is made of a material containing, for example, silicon dioxide. The source electrode 116 is in contact with each of the source region 114 and the contact region 118. The source electrode 116 is made of a material containing, for example, Ti, Al, and Si. The source wiring 119 is in contact with the source electrode 116. The source wiring 119 is electrically connected to the source electrode 116. The source wiring 119 covers the source electrode 116 and the interlayer insulating film 126. The drain electrode 120 is in contact with the silicon carbide substrate 10 on the second main surface 2.

[0066] In the above embodiment, the silicon carbide semiconductor device 300 is a MOSFET, but the silicon carbide semiconductor device 300 is not limited to a MOSFET. The silicon carbide semiconductor device 300 may be, for example, an IGBT (Insulated Gate Bipolar Transistor) or the like.

[0067] (Method for manufacturing silicon carbide semiconductor device) Next, a method for manufacturing silicon carbide semiconductor device 300 according to this embodiment will be described.

[0068] Fig. 12 is a schematic diagram illustrating a method for manufacturing a silicon carbide semiconductor device 300 according to this embodiment. As shown in Fig. 12, the method for manufacturing a silicon carbide semiconductor device 300 according to this embodiment includes a step (S1) of manufacturing a silicon carbide epitaxial substrate and a step (S40) of forming an electrode on the silicon carbide epitaxial substrate.

[0069] First, a step of manufacturing silicon carbide epitaxial substrate 100 according to this embodiment is performed. Specifically, a step (S10) of placing silicon carbide substrate 10 in transfer standby chamber 251, a step (S20) of transferring silicon carbide substrate 10 to growth chamber 252, and a step (S30) of forming silicon carbide epitaxial layer 20 on silicon carbide substrate 10 are performed. In this way, a silicon carbide epitaxial substrate having silicon carbide epitaxial layer 20 and silicon carbide substrate 10 is manufactured (see FIG. 8 ).

[0070] Next, a step of forming a body region is performed. Fig. 13 is a cross-sectional view showing the step of forming a body region. Specifically, p-type impurities such as aluminum are ion-implanted into drift layer 14 of silicon carbide epitaxial layer 20. This forms body region 113 having p-type conductivity. Body region 113 has a thickness of, for example, 0.9 µm.

[0071] Next, a step of forming a source region is performed. FIG. 14 is a cross-sectional view showing the step of forming the source region. Specifically, n-type impurities such as phosphorus are ion-implanted into the body region 113. This forms a source region 114 having n-type conductivity. The thickness of the source region 114 is, for example, 0.4 μm. The concentration of the n-type impurity contained in the source region 114 may be higher than the concentration of the p-type impurity contained in the body region 113.

[0072] Next, a p-type impurity such as aluminum is ion-implanted into the source region 114 to form a contact region 118. The contact region 118 is formed to penetrate the source region 114 and the body region 113 and to be in contact with the drift layer 14. The concentration of the p-type impurity contained in the contact region 118 may be higher than the concentration of the n-type impurity contained in the source region 114.

[0073] Next, activation annealing is performed to activate the ion-implanted impurities. The temperature of the activation annealing is preferably 1500°C or higher and 1900°C or lower, for example, about 1700°C. The activation annealing time is, for example, about 30 minutes. The atmosphere for the activation annealing is preferably an inert gas atmosphere, for example, an Ar atmosphere.

[0074] Next, a step of forming trenches in the first main surface 1 is performed. FIG. 15 is a cross-sectional view showing the step of forming trenches in the first main surface 1. As shown in FIG. 15, a mask 117 having openings is formed on the first main surface 1 including the source region 114 and the contact region 118. The source region 114, the body region 113, and a portion of the drift layer 14 are removed by etching using the mask 117. As an etching method, for example, reactive ion etching, particularly inductively coupled plasma reactive ion etching, can be used. Specifically, for example, inductively coupled plasma reactive ion etching using SF or a mixed gas of SF and O as a reactive gas can be used. As a result of the etching, recesses are formed in the first main surface 1.

[0075] Next, thermal etching is performed on the recesses. Thermal etching can be performed, for example, by heating the first main surface 1 with the mask 117 formed thereon in an atmosphere containing a reactive gas having at least one type of halogen atom. The at least one type of halogen atom includes at least one of chlorine (Cl) atoms and fluorine (F) atoms. The atmosphere includes, for example, Cl2, BCl3, SF6, or CF4. For example, thermal etching is performed using a mixed gas of chlorine gas and oxygen gas as the reactive gas, with the heat treatment temperature set to, for example, 700°C or higher and 1000°C or lower. The reactive gas may contain a carrier gas in addition to the above-mentioned chlorine gas and oxygen gas. Examples of the carrier gas that can be used include nitrogen gas, argon gas, and helium gas.

[0076] 15 , trenches 106 are formed in the first main surface 1 by thermal etching. The trenches 106 are defined by side surfaces 123 and a bottom surface 124. The side surfaces 123 are formed by the source region 114, the body region 113, and the drift layer 14. The bottom surface 124 is formed by the drift layer 14. Next, the mask 117 is removed from the first main surface 1.

[0077] Next, a step of forming a gate insulating film is performed. Fig. 16 is a cross-sectional view schematically illustrating the step of forming a gate insulating film. Specifically, silicon carbide epitaxial substrate 100 having trench 106 formed in first main surface 1 is heated in an oxygen-containing atmosphere at a temperature of, for example, 1300°C or higher and 1400°C or lower. This forms gate insulating film 115 that is in contact with drift layer 14 at bottom surface 124, in contact with drift layer 14, body region 113, and source region 114 at side surface 123, and in contact with source region 114 and contact region 118 at first main surface 1.

[0078] Next, a step of forming a gate electrode is performed. Fig. 17 is a cross-sectional view showing a step of forming a gate electrode and an interlayer insulating film. The gate electrode 127 is formed inside the trench 106 so as to contact the gate insulating film 115. The gate electrode 127 is disposed inside the trench 106 and is formed on the gate insulating film 115 so as to face each of the side surface 123 and the bottom surface 124 of the trench 106. The gate electrode 127 is formed by, for example, an LPCVD (Low Pressure Chemical Vapor Deposition) method.

[0079] Next, an interlayer insulating film 126 is formed. The interlayer insulating film 126 is formed so as to cover the gate electrode 127 and to be in contact with the gate insulating film 115. The interlayer insulating film 126 is formed by, for example, chemical vapor deposition. The interlayer insulating film 126 is made of, for example, a material containing silicon dioxide. Next, the interlayer insulating film 126 and the gate insulating film 115 are partially etched so as to form openings over the source region 114 and the contact region 118. As a result, the contact region 118 and the source region 114 are exposed from the gate insulating film 115.

[0080] Next, a step of forming a source electrode is performed. The source electrode 116 is formed so as to contact each of the source region 114 and the contact region 118. The source electrode 116 is formed by, for example, a sputtering method. The source electrode 116 is made of, for example, a material containing Ti, Al, and Si.

[0081] Next, alloying annealing is performed. Specifically, the source electrode 116 in contact with each of the source region 114 and the contact region 118 is maintained at a temperature of, for example, 900°C or higher and 1100°C or lower for about 5 minutes. As a result, at least a portion of the source electrode 116 is silicided. This forms the source electrode 116 in ohmic contact with the source region 114. Preferably, the source electrode 116 forms ohmic contact with the contact region 118.

[0082] Next, the source wiring 119 is formed. The source wiring 119 is electrically connected to the source electrode 116. The source wiring 119 is formed so as to cover the source electrode 116 and the interlayer insulating film 126.

[0083] Next, the step of forming the drain electrode 120 is carried out. First, the silicon carbide substrate 10 is polished on the second main surface 2. Next, the drain electrode 120 is formed. The drain electrode 120 is formed so as to be in contact with the silicon carbide substrate 10 on the second main surface 2. In this way, the silicon carbide semiconductor device 300 is manufactured (see FIG. 11 ).

[0084] Next, the effects of the method for manufacturing silicon carbide epitaxial substrate 100 and the method for manufacturing silicon carbide semiconductor device 300 according to this embodiment will be described.

[0085] Before growing the silicon carbide epitaxial layer 20, silicon carbide foreign matter may be attached to the silicon carbide substrate 10. When the silicon carbide epitaxial layer 20 is formed on the silicon carbide substrate 10 in this state, step-flow growth is hindered, and defects (triangular defects or downfalls) composed of silicon carbide with a 3C polytype may occur. When manufacturing a silicon carbide semiconductor device, the coverage of the gate insulating film formed on the defect deteriorates. As a result, silicon carbide semiconductor devices formed in regions where the defect exists are often determined to have a breakdown voltage defect or the like in initial characteristic tests at the wafer stage. This reduces the yield of silicon carbide semiconductor devices.

[0086] The inventors have conducted extensive research into ways to reduce silicon carbide foreign matter adhering to silicon carbide substrate 10, and as a result have obtained the following findings and discovered a method for manufacturing silicon carbide epitaxial substrate 100 according to this embodiment.

[0087] The inventors have focused on the fact that the adhesion of silicon carbide foreign matter to silicon carbide substrate 10 occurs in the process of transferring silicon carbide substrate 10 from transfer standby chamber 251 to growth chamber 252. Specifically, when silicon carbide substrate 10 is transferred to growth chamber 252, a member inside growth chamber 252 is thermally deformed due to a sudden temperature change. As a result, the inventors have found that the silicon carbide foreign matter adhering to the member peels off and adheres to silicon carbide substrate 10.

[0088] According to the method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure, in the step of transferring silicon carbide substrate 10 from transfer standby chamber 251 to growth chamber 252, transfer of silicon carbide substrate 10 is temporarily stopped with at least a portion of silicon carbide substrate 10 inside growth chamber 252. This allows silicon carbide substrate 10 to be preheated inside growth chamber 252. Therefore, the temperature difference between silicon carbide substrate 10 and a member in growth chamber 252 to which silicon carbide foreign matter is attached can be reduced compared to a case in which transfer of silicon carbide substrate 10 is not temporarily stopped. As a result, the amount of thermal deformation of the member to which silicon carbide foreign matter is attached can be reduced, thereby preventing the silicon carbide foreign matter from falling onto silicon carbide substrate 10. This allows an improvement in the yield of silicon carbide semiconductor devices manufactured using the silicon carbide epitaxial substrate according to the present disclosure.

[0089] Furthermore, as a result of more detailed investigation, it was found that yellow silicon carbide foreign matter was attached to the heat insulating material 202 and the heating element 203, which are made of carbon. The yellow silicon carbide foreign matter is thought to be carbon-rich silicon carbide foreign matter. Silver silicon carbide foreign matter was attached to the liner pipe 201, which is made of quartz. The silver silicon carbide foreign matter is thought to be silicon-rich silicon carbide foreign matter. The method for producing a silicon carbide epitaxial substrate is mainly intended to prevent the yellow silicon carbide foreign matter from falling onto the silicon carbide substrate 10, but it is also possible to prevent the silver silicon carbide foreign matter from falling onto the silicon carbide substrate 10.

[0090] According to the method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure, transportation of silicon carbide substrate 10 may be temporarily stopped before silicon carbide substrate 10 enters the space surrounded by thermal insulation material 202. This makes it possible to prevent silicon carbide foreign matter adhering to thermal insulation material 202 from falling onto silicon carbide substrate 10.

[0091] According to the method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure, in the step of transferring silicon carbide substrate 10 from transfer standby chamber 251 to growth chamber 252, the temperature of growth chamber 252 is 300°C or higher. In the step of placing silicon carbide substrate 10 in transfer standby chamber 251, the temperature of transfer standby chamber 251 is 10°C or higher. This allows silicon carbide substrate 10 to be preheated in transfer standby chamber 251. This reduces the temperature difference between silicon carbide substrate 10 and a member in growth chamber 252 to which silicon carbide foreign matter is attached. As a result, the amount of thermal deformation of the member to which silicon carbide foreign matter is attached can be reduced, thereby preventing the silicon carbide foreign matter from falling onto silicon carbide substrate 10. This improves the yield of silicon carbide semiconductor devices manufactured using the silicon carbide epitaxial substrate according to the present disclosure.

[0092] According to the method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure, in the step of placing silicon carbide substrate 10 in transport standby chamber 251, the temperature of transport standby chamber 251 may be 300°C or higher. This makes it possible to further reduce the temperature difference between silicon carbide substrate 10 and the member to which silicon carbide foreign matter is attached in growth chamber 252. As a result, it is possible to further prevent silicon carbide foreign matter from falling onto silicon carbide substrate 10.

[0093] According to the method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure, in the step of transferring silicon carbide substrate 10 from transfer standby chamber 251 to growth chamber 252, the transfer speed of silicon carbide substrate 10 is 200 mm / sec or less. As a result, silicon carbide substrate 10, while at a high temperature, approaches the member in growth chamber 252 to which the silicon carbide foreign matter is attached. This reduces the temperature difference between the member to which the silicon carbide foreign matter is attached and silicon carbide substrate 10. As a result, the amount of thermal deformation of the member to which the silicon carbide foreign matter is attached can be reduced, thereby preventing the silicon carbide foreign matter from falling onto silicon carbide substrate 10. This improves the yield of silicon carbide semiconductor devices manufactured using the silicon carbide epitaxial substrate according to the present disclosure.

[0094] According to the method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure, silicon carbide substrate 10 may be transported at a first transport speed A1, and then at a second transport speed A2 slower than first transport speed A1. This allows silicon carbide substrate 10 to be transported at a high speed in transport standby chamber 251, and at a low speed in growth chamber 252. This reduces the total transport time of silicon carbide substrate 10, while preventing silicon carbide foreign matter from falling onto silicon carbide substrate 10. This improves the yield of silicon carbide semiconductor devices manufactured using the silicon carbide epitaxial substrate according to the present disclosure.

[0095] When the temperature of growth chamber 252 is high, the temperature difference between the member to which the silicon carbide foreign matter is attached and silicon carbide substrate 10 becomes large. In this case, the amount of thermal deformation of the member to which the silicon carbide foreign matter is attached becomes large. According to the method for manufacturing a silicon carbide epitaxial substrate according to the present disclosure, in the step of transferring silicon carbide substrate 10 from transfer standby chamber 251 to growth chamber 252, the temperature of growth chamber 252 may be 500°C or higher. When the temperature of growth chamber 252 is high, it is possible to effectively prevent silicon carbide foreign matter from falling onto silicon carbide substrate 10.

[0096] Furthermore, since the initial temperature of growth chamber 252 is high, it is possible to reduce the time required for the temperature of growth chamber 252 to reach the temperature (about 1650°C) required to form silicon carbide epitaxial layer 20. As a result, the time required for the process of forming silicon carbide epitaxial layer 20 can be reduced.

[0097] According to the method for manufacturing a silicon carbide semiconductor device according to the present disclosure, the yield of silicon carbide semiconductor devices can be improved.

[0098] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the above-described embodiments, and it is intended to include any modifications within the scope of the claims and meanings equivalent to the claims. [Explanation of symbols]

[0099] 1 First main surface 2 Second main surface 3 Orientation Flat 4 Arc-shaped section 5 outer edge 10 Silicon carbide substrate 11 Buffer layer 14 Drift Layer 15 Third main surface 20 Silicon carbide epitaxial layer 100 Silicon carbide epitaxial substrate 101 1st direction 102 Second direction 103 Third direction 106 Trench 113 Body Region 114 Source Region 115 Gate insulating film 116 Source electrode 117 Mask 118 Contact Area 119 Source wiring 120 drain electrode 123 Side 124 bottom 126 Interlayer insulating film 127 Gate electrode 201 Liner pipe 202 Insulation material 203 Heating element 204 Quartz tube 206 Stages 209 Rotational Axis 210 Holder 250 Manufacturing equipment 251 Transfer waiting chamber 252 Growth Chamber 261 Storage Unit 262 Transport Robot Arm 264 Gate Valve 300 Silicon carbide semiconductor device A1 First conveying speed A2 Second conveying speed A3 Third conveying speed T1 Time 1 T2 Time point 2 T3 Time 3 T4 Time 4 T5 5th time point T6 6th point T7 7th time point T8 8th time point W1 Maximum diameter

Claims

1. placing the silicon carbide substrate in a transfer waiting chamber; transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber; forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber; a temperature of the growth chamber being 300°C or higher, and a step of temporarily stopping the transfer of the silicon carbide substrate when at least a portion of the silicon carbide substrate is in the growth chamber, in the step of transferring the silicon carbide substrate from the transfer standby chamber to the growth chamber.

2. the growth chamber includes insulation; 2. The method for manufacturing a silicon carbide epitaxial substrate according to claim 1, wherein transportation of the silicon carbide substrate is temporarily stopped before the silicon carbide substrate enters the space surrounded by the heat insulating material.

3. placing the silicon carbide substrate in a transfer waiting chamber; transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber; forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber; In the step of transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber, a temperature of the growth chamber is 300° C. or higher; The method for manufacturing a silicon carbide epitaxial substrate, wherein in the step of placing the silicon carbide substrate in a transfer standby chamber, the temperature of the transfer standby chamber is 10° C. or higher.

4. 4. The method for manufacturing a silicon carbide epitaxial substrate according to claim 3, wherein in the step of placing the silicon carbide substrate in a transfer standby chamber, the temperature of the transfer standby chamber is 300°C or higher.

5. placing the silicon carbide substrate in a transfer waiting chamber; transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber; forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber; a temperature of the growth chamber being 300°C or higher and a transport speed of the silicon carbide substrate being 200 mm / sec or lower in the step of transporting the silicon carbide substrate from the transport standby chamber to a growth chamber.

6. placing the silicon carbide substrate in a transfer waiting chamber; transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber; forming a silicon carbide epitaxial layer on the silicon carbide substrate in the growth chamber; In the step of transporting the silicon carbide substrate from the transport standby chamber to a growth chamber, a temperature of the growth chamber is 300°C or higher, and the silicon carbide substrate is transported at a first transport speed and then at a second transport speed slower than the first transport speed; The method for manufacturing a silicon carbide epitaxial substrate, wherein the first transport speed is 200 mm / sec or less.

7. 7. The method for manufacturing a silicon carbide epitaxial substrate according to claim 6, wherein the second transport speed is 100 mm / sec or less.

8. the growth chamber has a heating element; The method for manufacturing a silicon carbide epitaxial substrate according to claim 1 , wherein the silicon carbide substrate is disposed inside the heating element.

9. 8. The method for manufacturing a silicon carbide epitaxial substrate according to claim 1, wherein in the step of transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber, a temperature of the growth chamber is 500°C or higher.

10. 8. The method for manufacturing a silicon carbide epitaxial substrate according to claim 1, wherein in the step of transferring the silicon carbide substrate from the transfer standby chamber to a growth chamber, a temperature of the growth chamber is 1200°C or less.

11. a step of manufacturing a silicon carbide epitaxial substrate by the method for manufacturing a silicon carbide epitaxial substrate according to any one of claims 1 to 7; and forming an electrode on the silicon carbide epitaxial substrate.

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