SiC wafer manufacturing equipment

Abstract

To create a SiC wafer that is less likely to contain defects and to eliminate the need for a separate process from a process for manufacturing the SiC wafer.SOLUTION: A loading portion 50 includes a susceptor portion 60 having a mounting surface 61a on which a rear surface 10b side of a seed substrate 10 is mounted, and a guide portion 70 that is arranged in the susceptor portion 60 to surround the seed substrate 10. Then, when growing an epitaxial layer 11, a first interval L1 between the seed substrate 10 and the guide portion 70 on the upstream side in the step flow growth direction is made narrower than a second interval L2 between the seed substrate 10 and the guide portion 70 on the downstream side in the step flow growth direction, and the temperature of the guide portion 70 is lower than that of the seed substrate 11 when growing the epitaxial layer 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a SiC wafer manufacturing apparatus for manufacturing SiC wafers by growing an epitaxial layer on a seed substrate made of silicon carbide (hereinafter also simply referred to as SiC) and having an off-axis angle. [Background technology]

[0002] It has been proposed to fabricate a SiC wafer by growing an epitaxial layer on a seed substrate made of SiC and having an off-axis angle. It has also been reported that when an epitaxial layer is grown on a seed substrate made of SiC, the epitaxial layer grows in a step-flow manner. Furthermore, it has been reported that when an epitaxial layer is grown on a seed substrate having an off-axis angle, defects including irregularities are likely to occur upstream of the step-flow growth direction.

[0003] Furthermore, if defects, including unevenness, occur in a SiC wafer, and a semiconductor device such as a MOSFET is formed using the SiC wafer with the defects, stress may concentrate in the uneven parts during heat treatment, potentially causing the SiC wafer to crack. Furthermore, if the process of forming a semiconductor device includes a step of placing a resist on the SiC wafer, the resist may easily remain in the uneven parts when the resist is peeled off, potentially becoming foreign matter. Note that MOSFET is an abbreviation for metal oxide semiconductor field effect transistor.

[0004] For this reason, for example, Patent Document 1 proposes growing an epitaxial layer on a seed substrate to form a SiC wafer, and then removing a portion of the SiC wafer located upstream in the step-flow growth direction. That is, Patent Document 1 proposes growing an epitaxial layer on a seed substrate to form a SiC wafer, and then removing the portion that is likely to form defects. Then, by forming a semiconductor element using the removed SiC wafer, it is possible to prevent the SiC wafer from cracking and the resulting SiC semiconductor device from containing foreign matter. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-034670 Summary of the Invention [Problem to be solved by the invention]

[0006] However, removing the portion of the SiC wafer located upstream in the step flow growth direction requires a process separate from the process for manufacturing the SiC wafer, which tends to increase the number of manufacturing processes.

[0007] In view of the above, an object of the present invention is to provide a SiC wafer manufacturing apparatus that can produce SiC wafers that are less likely to contain defects, while eliminating the need for a process separate from the process for manufacturing SiC wafers. [Means for solving the problem]

[0008] Claim 1 for achieving the above object provides a manufacturing apparatus for SiC wafers, the apparatus comprising: a reaction chamber forming section (20) for forming a reaction chamber (20a) into which a reaction gas is introduced and in which an epitaxial layer (11) made of SiC is grown by step flow on a surface (10a) side of a seed substrate (10) made of SiC and having an off-angle; a reaction gas supply pipe (30) provided in the reaction chamber for supplying the reaction gas for growing the epitaxial layer to the reaction chamber; a mounting section (50) arranged in the reaction chamber and on which the seed substrate is placed; and a rotating device (41) having a cylindrical section (41) on one end side of which the mounting section is placed, and which rotates the mounting section together with the seed substrate. The mounting section has a susceptor section (60) having a mounting surface (61a) on which the back surface (10b) of the seed substrate is placed, and a guide section (70) arranged on the susceptor section so as to surround the seed substrate, and when growing an epitaxial layer, a first distance (L1) between the seed substrate and the guide section on the upstream side of the step-flow growth direction is narrower than a second distance (L2) between the seed substrate and the guide section on the downstream side of the step-flow growth direction, and the guide section is configured to have a lower temperature than the seed substrate when growing an epitaxial layer.

[0009] According to this, when growing an epitaxial layer, the guide portion is at a lower temperature than the seed substrate. Also, when growing an epitaxial layer, the first distance between the seed substrate and the guide portion is narrower than the second distance between the seed substrate and the guide portion. Therefore, when growing an epitaxial layer, the epitaxial layer is less likely to grow on the upstream side of the growth direction, where defects are more likely to occur. Therefore, the SiC wafer is less likely to contain irregularities, and can be used directly to manufacture semiconductor devices without performing a process of removing the upstream side of the growth direction.

[0010] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a schematic diagram showing a manufacturing apparatus for a SiC wafer according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing the relationship between surface roughness and emissivity in SiC. [Figure 3] FIG. 2 is a schematic diagram of the vicinity of a seed substrate when an epitaxial layer is grown. [Figure 4] FIG. 2 is a schematic diagram of the vicinity of the seed substrate after the epitaxial layer is grown. [Figure 5] FIG. 2 is a diagram showing conditions for growing an epitaxial layer. [Figure 6] FIG. 1 is a diagram showing the relationship between the distance from the center of the seed substrate, the growth rate, and the heat flux. [Figure 7] FIG. 1 is a plan view of a SiC wafer. [Figure 8] 8 is a binarized optical microscope photograph of region A in FIG. 7 when the first distance is set to 0.0 mm. FIG. [Figure 9] FIG. 8 is a binarized optical microscope photograph of region A in FIG. 7 when the first gap is set to 1.5 mm. [Figure 10] FIG. 8 is a binarized optical microscope photograph of region A in FIG. 7 when the first gap is set to 3.0 mm. [Figure 11] FIG. 10 is a diagram showing the relationship between the distance from the center of the SiC wafer and the step height. [Figure 12] FIG. 10 is a diagram illustrating the relationship between distance and step. [Figure 13] FIG. 10 is a plan view showing a state before rotation when the seed substrate is placed on the mounting portion. [Figure 14] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. [Figure 15] FIG. 10 is a plan view showing a state in which the seed substrate is placed on the mounting portion and is being rotated. [Figure 16] FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. [Figure 17] FIG. 11 is a plan view showing a state in which the seed substrate is being rotated when placed on a mounting portion in the third embodiment. [Figure 18] FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiments, parts that are identical or equivalent to each other will be denoted by the same reference numerals.

[0013] (First embodiment) A first embodiment will be described with reference to the drawings. As shown in Fig. 1, a SiC wafer manufacturing apparatus (hereinafter simply referred to as a manufacturing apparatus) 1 has a chamber 20 that forms a reaction chamber 20a in which an epitaxial layer 11 serving as a semiconductor layer is grown on a surface 10a side of a seed substrate 10 to manufacture a SiC wafer 12. In this embodiment, the chamber 20 corresponds to a reaction chamber forming part that forms the reaction chamber 20a.

[0014] The chamber 20 is provided at its upper side with a reactive gas supply pipe 30 for supplying a reactive gas for growing a crystal thin film onto the surface 10a of the seed substrate 10. In this embodiment, in order to epitaxially grow SiC, the reactive gas contains, for example, a source gas made of silane (SiH4) and propane (C3H8), and a carrier gas made of hydrogen and hydrogen chloride (HCl).

[0015] Specifically, reactive gas supply pipe 30 is disposed above chamber 20 so as to open at a position facing surface 10a of seed substrate 10. As a result, reactive gas is supplied to reaction chamber 20a from a direction intersecting surface 10a of seed substrate 10 (i.e., a direction substantially perpendicular to surface 10a) toward surface 10a of seed substrate 10. For this reason, manufacturing apparatus 1 of this embodiment can be said to have a downflow-type gas supply structure in which reactive gas is blown down toward surface 10a of seed substrate 10.

[0016] Further, in the reaction chamber 20a, a rotation device 40 is disposed on the lower side, on which the seed substrate 10 is disposed. In this embodiment, the seed substrate 10 is disposed on a mounting portion 50 disposed on the rotation device 40.

[0017] The rotation device 40 includes a cylindrical portion 41, a rotation shaft 42, and a drive unit 43. The cylindrical portion 41 is a bottomed cylindrical member that defines a hollow chamber 41a, and the mounting unit 50 is disposed at the end on the open end side. The open end side of the cylindrical portion 41 is disposed so as to face the upper side of the chamber 20 (i.e., the side of the reaction gas supply pipe 30).

[0018] The rotating shaft 42 is a shaft that rotates due to the output of the driving unit 43, and is connected to the cylindrical portion 41 so as to be rotatable integrally with the cylindrical portion 41. The driving unit 43 is composed of a motor or the like that outputs a rotational force, and rotates the rotating shaft 42. In the rotation device 40 configured in this manner, the rotating shaft 42 rotates due to the output of the driving unit 43, and the cylindrical portion 41 and the mounting portion 50 rotate integrally.

[0019] The mounting section 50 has a configuration including a susceptor section 60 and a guide section 70. The susceptor section 60 has an outer shape that matches the open end of the cylindrical section 41, and when placed at the open end of the cylindrical section 41, it substantially closes the cylindrical section 41. As a result, the hollow chamber 41a of the cylindrical section 41 is substantially closed.

[0020] Specifically, the susceptor part 60 is plate-shaped and has one surface 60a and another surface 60b, and a recess 61 for accommodating the seed substrate 10 is formed in the center of the one surface 60a. Therefore, the susceptor part 60 has a step 62 formed at the boundary between the one surface 60a and the recess 61. The recess 61 is formed so that the center of the recess 61 coincides with the central axis of the rotation shaft 42 when the susceptor part 60 is placed in the rotation device 40.

[0021] Furthermore, the susceptor portion 60 has a step portion 63 formed on the outer edge portion of the other surface 60b side to be fitted into the open end of the tubular portion 41. The susceptor portion 60 is disposed in the tubular portion 41 by fitting the step portion 63 into the open end of the tubular portion 41.

[0022] The guide part 70 has a cylindrical shape that matches the shape of the outer edge of the susceptor part 60, and is provided at one end with a step part 71. The guide part 70 is provided on the susceptor part 60 by fitting the step part 71 into the step part 62 of the susceptor part 60.

[0023] Here, the guide portion 70 of this embodiment is configured to have a higher emissivity than the seed substrate 10. According to the inventors' studies, as shown in FIG. 2 , it has been confirmed that the emissivity of SiC increases as the surface roughness Ra increases. Therefore, in this embodiment, the guide portion 70 is made of SiC and has a surface roughness Ra greater than that of the seed substrate 10. The surface roughness Ra of the guide portion 70 can be increased, for example, by adjusting the processing tool used when processing a SiC ingot to form the guide portion 70. The surface roughness Ra of the guide portion 70 can also be increased by, for example, performing a blasting process after processing to increase the surface roughness Ra. The guide portion 70 of this embodiment may be made of a material other than SiC, such as carbide, as long as the emissivity is greater than that of the seed substrate 10.

[0024] The seed substrate 10 is placed on the mounting part 50 such that the bottom surface 61a of the recess 61 of the susceptor part 60 serves as the mounting surface, and the back surface 10b faces the bottom surface 61a. In this embodiment, the guide part 70 is configured as described above. Therefore, it can be said that the seed substrate 10 is disposed in the space 70a within the guide part 70.

[0025] A first heater 80 is disposed in hollow chamber 41a as a heating device that heats seed substrate 10 from the back surface 10b side. First heater 80 is, for example, a resistance heater made of carbon, and although not shown, is connected to a control unit or the like to heat seed substrate 10 to a predetermined temperature. In this embodiment, first heater 80 corresponds to the first heating device.

[0026] In the chamber 20, a second heater 90 is disposed above the rotation device 40 as a heating device that heats the seed substrate 10 from the front surface 10a side. The second heater 90 is, for example, a resistance heater made of carbon, and although not shown, is connected to a control unit or the like to heat the seed substrate 10 to a predetermined temperature. The second heater 90 is disposed, for example, in a ring shape along the inner wall surface of the chamber 20. In this embodiment, the second heater 90 corresponds to the second heating device.

[0027] As will be described in detail later, first heater 80 and second heater 90 in this embodiment are driven so that the temperature of hollow chamber 41 a is higher than the temperature of reaction chamber 20 a. In other words, first heater 80 and second heater 90 are driven so that the temperature of back surface 10 b of seed substrate 10 is higher than the temperature of front surface 10 a.

[0028] Furthermore, a reaction gas exhaust pipe 100 for exhausting reacted gas and unreacted gas is provided on the lower side of the chamber 20. The reaction gas exhaust pipe 100 is connected to a vacuum pump (not shown) on the side opposite to the chamber 20 side, thereby maintaining the reaction chamber 20a at a predetermined pressure.

[0029] Although not specifically shown, an elevator device is disposed in hollow chamber 41a to assist a transfer robot in carrying the mounting part 50, on which seed substrate 10 is placed, into reaction chamber 20a and in carrying out the mounting part 50 from reaction chamber 20a. This elevator device has the function of, for example, lifting mounting part 50 and separating it from cylindrical part 41 when carrying out the mounting part 50, thereby handing over the mounting part 50 to the transfer robot. However, manufacturing apparatus 1 may not necessarily carry in and out the mounting part 50 on which seed substrate 10 is placed, but may carry in and out only seed substrate 10 without moving mounting part 50.

[0030] The above is the configuration of manufacturing apparatus 1 in this embodiment. Next, a method for growing epitaxial layer 11 on surface 10a of seed substrate 10 using manufacturing apparatus 1 will be described.

[0031] First, in the manufacturing apparatus 1 described above, the mounting unit 50 on which the seed substrate 10 is placed is rotated by the rotation device 40 at, for example, 200 rpm, while the reaction chamber 20a is heated to approximately 1600 to 1750°C by the first and second heaters 80, 90. Then, a reaction gas is supplied from the reaction gas supply pipe 30 toward the reaction chamber 20a. As a result, the silane gas and propane gas contained in the reaction gas react with each other, and an epitaxial layer 11 made of SiC is grown on the seed substrate 10 by step flow growth, thereby producing a SiC wafer 12.

[0032] However, in this embodiment, the epitaxial layer 11 is grown specifically as follows. First, the seed substrate 10 is made of SiC, and is, for example, a 4H type substrate having an off-angle of 0 to 8° with respect to the (0001) Si plane. However, the seed substrate 10 is not limited to this, and may be a 6H type or a 3C type substrate, and the specific value of the off-angle may also be changed as appropriate.

[0033] In this embodiment, when reaction chamber 20a is heated by first heater 80 and second heater 90, back surface 10b of seed substrate 10 is made to be at a higher temperature than front surface 10a. Specifically, first heater 80 and second heater 90 are driven so that the temperature of hollow chamber 41a is higher than the temperature of reaction chamber 20a. In this case, in this embodiment, as described above, the emissivity of guide portion 70 is made higher than the emissivity of seed substrate 10. Therefore, guide portion 70, which has a higher emissivity, dissipates more heat than seed substrate 10, and the temperature of guide portion 70 is lower than that of seed substrate 10.

[0034] 3, in this embodiment, epitaxial layer 11 is grown on seed substrate 10 in a step-flow growth direction (hereinafter simply referred to as the growth direction) while the following relationship is satisfied: That is, epitaxial layer 11 is grown on seed substrate 10 such that a first distance L1 between seed substrate 10 on the upstream side in the growth direction and guide portion 70 is narrower than a second distance L2 between seed substrate 10 on the downstream side in the growth direction and guide portion 70.

[0035] As a result, the temperature gradient in the portion corresponding to first distance L1 becomes larger than the temperature gradient in the portion corresponding to second distance L2, and therefore, on the upstream side in the growth direction, the source material M contained in the reaction gas tends to flow toward guide portion 70. Therefore, as shown in Fig. 4, it becomes difficult for epitaxial layer 11 to grow on the upstream side in the growth direction of seed substrate 10. In other words, when epitaxial layer 11 is grown, it becomes difficult for the epitaxial layer to grow on the upstream side in the growth direction where defects such as unevenness are likely to be formed.

[0036] The present inventors performed a simulation of growing epitaxial layer 11 under the conditions shown in Fig. 5, and obtained the results shown in Fig. 6. The conditions for growing epitaxial layer 11 were, as shown in Fig. 5, a central temperature at surface 10a of seed substrate 10 of 1625°C, a silane flow rate of 500 sccm, a propane flow rate of 91 sccm, a hydrogen flow rate of 90 sccm, and a hydrogen chloride flow rate of 5000 sccm. The pressure in chamber 20 was set to 27 kPa, and the growth amount of epitaxial layer 11 was set to 140 µm. The temperature difference ΔT between seed substrate 10 and guide member 70 was set to 4.6°C, and first distance L1 was varied between 0 and 3.0 mm.

[0037] As shown in FIG. 6, it was confirmed that the narrower the first interval L1 is, the easier it is for the source material M to flow toward the guide portion 70 on the upstream side of the growth direction of the epitaxial layer 11, and therefore the slower the growth rate is. It was also confirmed that the narrower the first interval L1 is, the greater the magnitude of the heat flux is on the upstream side of the growth direction of the epitaxial layer 11. Note that FIG. 6 shows the distance along the surface direction from the center of the seed substrate 10, and since a 6-inch substrate is used, 75 mm is the edge of the seed substrate 10. Furthermore, in FIG. 6, the heat flux from the seed substrate 10 toward the epitaxial layer 11 is shown as negative, and the magnitude of the heat flux corresponds to the magnitude of the thermal gradient. In other words, it was confirmed from FIG. 6 that the narrower the first interval L1 is, the greater the temperature gradient is.

[0038] The inventors then actually grew an epitaxial layer 11 on a seed substrate 10, and obtained the results shown in FIGS. 8 to 12. Note that FIGS. 8 to 12 show the results when the epitaxial layer 11 was grown under the conditions shown in FIG. 5 above. Also, FIGS. 8 to 10 are binarized diagrams of the results obtained with an optical microscope for region A located upstream in the growth direction of an SiC wafer 12 grown by step flow growth as shown in FIG. 7. FIG. 11 shows the step height, with a position 70 mm away from the center of the SiC wafer 12 as the reference (i.e., step height 0). In FIG. 12, both ends (i.e., distances of 0 mm and 2 mm) of the portion along line XII-XII in FIGS. 8 to 10 are used as the reference (i.e., step height 0). In FIGS. 11 and 12, a first distance L1 of 0.0 mm refers to a state in which the seed substrate 10 and the guide portion 70 are in contact with each other. Also, in Figures 11 and 12, a first distance L1 of 1.5 μm indicates that the first distance L1 and the second distance L2 are equal, and a first distance L1 of 3.0 μm indicates that the first distance L1 is wider than the second distance L2.

[0039] 8 to 10, it is confirmed that the narrower the first distance L1, the less likely defects including irregularities are to occur. 11 and 12 also confirm that the narrower the first distance L1, the fewer irregularities there are, and that when the first distance L1 is 0.0 mm, almost no irregularities are formed.

[0040] Therefore, in this embodiment, the first distance L1 is made narrower than the second distance L2. Specifically, in this embodiment, in order to make the first distance L1 narrower than the second distance L2, the epitaxial layer 11 is grown on the seed substrate 10 as follows.

[0041] 13 and 14, the bottom surface of recess 61 of susceptor part 60 is made to be a perfect circle. However, the center of recess 61 is made to coincide with center 60c of susceptor part 60 (i.e., the central axis of rotation shaft 42) in the normal direction (hereinafter simply referred to as the normal direction) to the planar direction of bottom surface 61a of susceptor part 60. Furthermore, center 10c of seed substrate 10 is positioned upstream of center 60c of susceptor part 60 in the growth direction.

[0042] Then, in this state, the rotation shaft 42 is rotated to grow an epitaxial layer 11 on the seed substrate 10. At this time, as shown in FIGS. 15 and 16 , the center 10c of the seed substrate 10 is positioned upstream of the center 60c of the susceptor unit 60 in the growth direction. Therefore, the centrifugal force generated by the rotation of the susceptor unit 60 displaces the seed substrate 10 upstream in the growth direction and into contact with the guide unit 70. In other words, the first distance L1 becomes 0.0 mm. Therefore, the epitaxial layer 11 can be grown on the seed substrate 10 with the first distance L1 narrower than the second distance L2. Note that FIG. 8 above shows the results of this method when the first distance L1 is set to 0.0 mm.

[0043] According to the embodiment described above, when growing epitaxial layer 11, guide portion 70 is set to a temperature lower than that of seed substrate 10. Furthermore, when growing epitaxial layer 11, first distance L1 between seed substrate 10 and guide portion 70 is set to be narrower than second distance L2 between seed substrate 10 and guide portion 70. Therefore, when growing epitaxial layer 11, epitaxial layer 11 is less likely to grow on the upstream side of the growth direction, where defects are more likely to occur. Therefore, SiC wafer 12 is less likely to contain irregularities, and can be used as is to manufacture semiconductor devices without performing a process of removing the upstream side of the growth direction.

[0044] In this embodiment, the second distance L2 is wider than the first distance L1. This prevents the epitaxial layer 11 from being difficult to grow on the downstream side of the growth direction when the epitaxial layer 11 is grown. This allows the epitaxial layer 11 to grow with good crystal quality on the downstream side of the growth direction of the SiC wafer 12.

[0045] (1) In this embodiment, the reaction chamber 20a is heated using the first heater 80 and the second heater 90. This makes it easier to adjust the magnitude of the temperature gradient in the portion corresponding to the first distance L1 and the magnitude of the temperature gradient in the portion corresponding to the second distance L2.

[0046] (2) In the present embodiment, by adjusting the position of seed substrate 10 when it is placed on susceptor portion 60, first distance L1 can be set to 0.0 mm when growing epitaxial layer 11. Therefore, a special configuration for setting first distance L1 to 0.0 mm when growing epitaxial layer 11 is not required, and manufacturing apparatus 1 can be prevented from becoming complicated.

[0047] (Second embodiment) A second embodiment will be described. This embodiment is different from the first embodiment in that the configuration of the guide portion 70 is changed. As the rest of the configuration is the same as the first embodiment, a description thereof will be omitted here.

[0048] The basic configuration of the manufacturing apparatus 1 of this embodiment is the same as that of the first embodiment. However, in this embodiment, the emissivity of the guide portion 70 is lower than the emissivity of the seed substrate 10. For example, the guide portion 70 is made of SiC and has a smaller surface roughness Ra than the seed substrate 10.

[0049] In this embodiment, when growing epitaxial layer 11 on seed substrate 10, first heater 80 and second heater 90 are adjusted so that front surface 10a of seed substrate 10 is hotter than back surface 10b. That is, the temperature of hollow chamber 41a is lower than the temperature of reaction chamber 20a. As a result, in this embodiment, when growing epitaxial layer 11, seed substrate 10 absorbs more heat than guide portion 70, and seed substrate 10 becomes hotter than guide portion 70. That is, guide portion 70 becomes cooler than seed substrate 10. Therefore, by making first distance L1 narrower than second distance L2 as in the first embodiment, growth of epitaxial layer 11 on the upstream side in the growth direction can be suppressed.

[0050] As in the present embodiment described above, the emissivity of guide portion 70 may be configured to be lower than the emissivity of seed substrate 10. Even with this configuration, the same effects as those of the first embodiment can be obtained by adjusting first heater 80 and second heater 90 so that front surface 10a of seed substrate 10 is at a higher temperature than back surface 10b and by making first distance L1 narrower than second distance L2.

[0051] (Third embodiment) A third embodiment will be described. This embodiment is different from the first embodiment in that the configuration of the guide portion 70 is changed. As the rest of the configuration is the same as the first embodiment, a description thereof will be omitted here.

[0052] 17 and 18, in the manufacturing apparatus 1 of this embodiment, the guide member 70 has a portion whose thickness varies in the circumferential direction so that the center 70c of the internal space 70a is located downstream of the center 60c of the susceptor member 60 in the growth direction. The seed substrate 10 is positioned so as to coincide with the center 60c of the susceptor member and to abut against the guide member 70 located upstream in the growth direction. The variation in the thickness of the guide member 70 refers to the change in the length between the inner wall surface and the outer wall surface of the guide member 70.

[0053] According to the present embodiment described above, when growing an epitaxial layer, the guide portion 70 is at a lower temperature than the seed substrate 10, and the first distance L1 is narrower than the second distance L2, so that the same effect as in the first embodiment can be obtained.

[0054] (1) As in the present embodiment, the distance between the first gap L1 and the second gap L2 may be adjusted by adjusting the shape of the guide portion 70. In this case, by configuring the guide portion 70 to be separable from the susceptor portion 60, the shape of the guide portion 70 can be easily adjusted.

[0055] (Other embodiments) Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0056] For example, in the above-described embodiments, the first distance L1 is 0.0 mm when growing the epitaxial layer 11. However, as long as the first distance L1 is narrower than the second distance L2, the first distance L1 does not have to be 0.0 mm. For example, a support pin or the like may be disposed on the bottom surface 61 a of the susceptor part 60 so that the first distance L1 does not become 0.0 mm when the mounting part 50 is rotated.

[0057] In each of the above embodiments, the susceptor portion 60 and the guide portion 70 may be integrated.

[0058] Furthermore, the first embodiment does not necessarily have to include the second heater 90. Similarly, the second embodiment does not necessarily have to include the first heater 80.

[0059] The above embodiments may be combined. For example, the second embodiment may be combined with the third embodiment, and the shape of the guide portion 70 may be adjusted to adjust the first distance L1 and the second distance L2. [Explanation of symbols]

[0060] 10 types of substrates 10a surface 10b back side 20 Epitaxial layer 20 Chamber (reaction chamber forming part) 20a Reaction chamber 30 Reaction gas supply pipe 40 Rotating Device 41 Cylinder part 50 Mounting section 60 Susceptor part 61a Placement surface 70 Guide section 80 First heater (heating device) 90 Second heater (heating device) L1 1st interval L2 Second interval

Claims

1. A silicon carbide wafer manufacturing apparatus, a reaction chamber forming section (20) for forming a reaction chamber (20a) into which a reaction gas is introduced and in which an epitaxial layer (11) made of silicon carbide is grown by step flow on a surface (10a) side of a seed substrate (10) made of silicon carbide and having an off-angle; a reaction gas supply pipe (30) provided in the reaction chamber for supplying a reaction gas for growing the epitaxial layer to the reaction chamber; a mounting portion (50) disposed in the reaction chamber and on which the seed substrate is placed; a rotating device (40) having a cylindrical portion (41) on one end side of which the mounting portion is arranged and which rotates the mounting portion together with the seed substrate; a heating device (80, 90) for heating the seed substrate, the mounting portion includes a susceptor portion (60) having a mounting surface (61 a) on which a back surface (10 b) of the seed substrate is placed, and a guide portion (70) that is disposed on the susceptor portion in a state surrounding the periphery of the seed substrate, and is configured such that, when the epitaxial layer is grown, a first distance (L1) between the seed substrate and the guide portion on an upstream side in a step-flow growth direction is narrower than a second distance (L2) between the seed substrate and the guide portion on a downstream side in the step-flow growth direction; The silicon carbide wafer manufacturing apparatus is configured so that the guide portion has a lower temperature than the seed substrate when the epitaxial layer is grown.

2. the guide portion has a higher emissivity than the seed substrate, the heating device includes a first heating device (80) that heats the back surface side of the seed substrate and a second heating device (90) that heats the front surface side of the seed substrate; The silicon carbide wafer manufacturing apparatus according to claim 1 , wherein the first heating device and the second heating device are driven so that the temperature of the back surface side of the seed substrate is higher than the temperature of the front surface side.

3. the guide portion has a lower emissivity than the seed substrate, the heating device includes a first heating device (80) that heats the back surface side of the seed substrate and a second heating device (90) that heats the front surface side of the seed substrate; The silicon carbide wafer manufacturing apparatus according to claim 1 , wherein the first heating device and the second heating device are driven so that the temperature of the front surface side of the seed substrate is higher than the temperature of the back surface side.

4. 4. The silicon carbide wafer manufacturing apparatus according to claim 1, wherein the susceptor section is configured such that, in a direction normal to a surface direction of the mounting surface, a center of the seed substrate is located upstream of a center of the susceptor section in the step flow growth direction.

5. the guide portion is cylindrical and has a portion whose wall thickness varies in a circumferential direction, and a center (70c) of an internal space (70a) has a shape different from a center (60c) of the susceptor portion in a normal direction to a surface direction of the mounting surface of the susceptor portion, 4. The silicon carbide wafer manufacturing apparatus of claim 1, wherein the susceptor portion is configured to be arranged such that a center of the seed substrate coincides with a center of the susceptor portion in a direction normal to a surface direction of the mounting surface.

Images