JP6986960B2 - Silicon Carbide Single Crystal Ingot, Method for Manufacturing Silicon Carbide Single Crystal - Google Patents

Description

The present invention relates to a silicon carbide single crystal ingot and a method for producing a silicon carbide single crystal.

Silicon carbide (SiC), which is a semiconductor material, has a larger bandgap than Si (silicon), which is widely used as a device substrate. Therefore, power devices using silicon carbide single crystal substrates, high-frequency devices, and high-temperature operation Research is being conducted to manufacture devices and the like.

These devices are formed on a silicon carbide single crystal substrate obtained by cutting out from a silicon carbide single crystal ingot grown by a sublimation method or the like, by a chemical vapor deposition (CVD) or the like on an active region of the device. It is manufactured by using a SiC epitaxial wafer on which an epitaxial layer (film) is formed.

The silicon carbide single crystal substrate contains crystal defects called Threading Screw Dislocations (TSDs), which may propagate to the SiC epitaxial film directly above the silicon carbide single crystal substrate, thereby deteriorating the device characteristics. In order to prevent device deterioration caused by TSD, various techniques for reducing the number of TSDs contained in the silicon carbide single crystal substrate are being studied.

For example, in Patent Document 1, in the initial stage of growth of a silicon carbide single crystal, the outer peripheral portion of the silicon carbide single crystal is once squeezed and grown (necking) so that the diameter is smaller than that of the silicon carbide seed crystal. A technique for sweeping out existing TSD has been proposed.

Japanese Unexamined Patent Publication No. 2007-176718

However, when the necking is performed according to the method disclosed in Patent Document 1, the TSD is swept out over the entire outer peripheral portion of the silicon carbide single crystal ingot. Therefore, in the region on the upstream side of the step flow growth surface inclined by the off-angle (off-upstream region), the number of TSDs required for maintaining polymorphism is reduced, so that heterogeneous polymorphism is likely to occur, and the obtained carbide is obtained. The quality of the silicon single crystal substrate deteriorates.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a silicon carbide single crystal ingot in which the number of TSDs is reduced within a range in which high quality can be maintained. Another object of the present invention is to provide a method for producing a silicon carbide single crystal, which makes it possible to sweep out the internal TSD within a range in which high quality can be maintained.

In order to solve the above problems, the present invention employs the following means.

(1) The silicon carbide single crystal ingot according to one aspect of the present invention is a silicon carbide single crystal ingot formed on the main surface of the surface of the silicon carbide seed crystal having an offset angle with respect to the c-plane. At a predetermined position in the crystal growth direction of the silicon carbide single crystal ingot, the central axis side of the silicon carbide single crystal ingot is on the outer peripheral portion including at least a part on the offset upstream side and at least a part on the offset downstream side. It has a necking part that is recessed in.

(2) In the silicon carbide single crystal ingot according to (1), the necking portion is preferably at a distance of 10 mm or less from the silicon carbide seed crystal.

(3) The silicon carbide single crystal ingot according to any one of (1) or (2) has the necking portion, and the center of the cross section perpendicular to the crystal growth direction of the silicon carbide single crystal ingot is the center. In a plan view in the crystal growth direction, it is preferable that the silicon carbide seed crystal is separated from the center of the crystal growth surface by 2 mm or more.

(4) The method for producing a silicon carbide single crystal according to one aspect of the present invention is a method for producing a silicon carbide single crystal, in which a silicon carbide raw material is arranged on one side in the pit and the other in the pit. A silicon carbide seed crystal and a tubular guide member having an opening on one side facing the silicon carbide seed crystal are arranged on the side, and the center of the crystal growth surface of the silicon carbide seed crystal is set in the crystal growth direction. In a plan view, the sublimation gas is supplied to the silicon carbide seed crystal in a state of being offset from the center of the opening of the guide member.

(5) In the method for producing a silicon carbide single crystal according to (4), the center of the crystal growth surface of the silicon carbide seed crystal is from the center of the opening of the guide member in the plan view in the crystal growth direction. It is preferable to adjust the position of the silicon carbide seed crystal with respect to the guide member so as to be separated in a range of 1 mm or more and 5 mm or less.

(6) In the method for producing a silicon carbide single crystal according to any one of (4) or (5), the crystal growth surface of the silicon carbide seed crystal is formed from the opening of the guide member in the crystal growth direction. It is preferable to adjust the position of the silicon carbide seed crystal with respect to the guide member so as to be separated within a range of 5 mm or less.

The silicon carbide single crystal ingot of the present invention has a necking portion on an outer peripheral portion on a side other than the offset upstream side at a predetermined position in the crystal growth direction. The outer peripheral portion on the upstream side of the offset does not have a necking portion. Therefore, while holding the TSD inherent in the offset upstream side, the TSD inherent in the outer peripheral portion other than the offset upstream side can be swept out by the necking portion. Therefore, the silicon carbide single crystal ingot of the present invention suppresses the generation of heterogeneous polymorphs on the upstream side and reduces the number of internal TSDs within the range in which high quality can be maintained.

Further, in the method for producing a silicon carbide single crystal of the present invention, the TSD contained in the silicon carbide seed crystal propagates to the facet portion in the outer peripheral portion on the upstream side of the offset in the process of forming the silicon carbide single crystal ingot, but upstream of the offset. The outer peripheral portion on the side other than the side is swept out by the necking portion. Therefore, according to the method for producing a silicon carbide single crystal according to the present embodiment, the number of internal TSDs is reduced within the range in which the generation of heterogeneous polymorphs on the upstream side of the offset is suppressed and high quality can be maintained. Crystals can be produced.

It is sectional drawing (upper side), plan view (lower side) of the silicon carbide single crystal ingot which concerns on one Embodiment of this invention, and the seed crystal part thereof. It is sectional drawing of the manufacturing apparatus of the silicon carbide single crystal which concerns on one Embodiment of this invention. It is a figure which shows the manufacturing process of the silicon carbide single crystal which concerns on one Embodiment of this invention. It is an enlarged photograph of a part of the silicon carbide ingot obtained by the manufacturing method of the silicon carbide single crystal which concerns on one Embodiment of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings as appropriate. In the figure used in the following description, in order to make the features of the present invention easy to understand, the featured portions may be enlarged for convenience, and the dimensional ratios of each component may differ from the actual ones. There is. Further, the materials, dimensions, etc. exemplified in the following description are examples, and the present invention is not limited thereto, and can be appropriately modified and carried out within the range in which the effect of the present invention is exhibited. ..

(Silicon Carbide Single Crystal Ingot)
FIG. 1 is a cross-sectional view (upper side) of the silicon carbide single crystal ingot 101 according to the embodiment of the present invention and the seed crystal portion 102 as a base thereof along the crystal growth direction D, and a plan view from the crystal growth direction D. It is a plan view (lower side). The silicon carbide single crystal ingot 101 is formed by step flow growth on the main surface of the silicon carbide seed crystal 102 having an offset angle with respect to the c-plane.

The silicon carbide single crystal ingot 101 is located on the downstream side in the offset direction, except for at least a part of the upstream side in the offset direction when the silicon carbide single crystal is step-flow-grown at a predetermined position P in the crystal growth direction D. A necking portion (reduced diameter portion) 101c is provided on the outer peripheral portion (side wall surface 101a) including at least a part of the above.

In the following, when the normal vector of the {0001} plane is projected on the main surface of the basic single crystal (seed crystal), the direction opposite to the direction of the projected vector is referred to as "offset direction". In the silicon carbide single crystal ingot 101 of FIG. 1, the direction from the left side to the right side is the offset direction S. The side facing the projected vector (right side) is referred to as the "offset downstream side", and the opposite side (left side) is referred to as the "offset upstream side".

Necking unit 101c, the silicon carbide single crystal ingot 101, a portion of the side wall surface 101a, which means the recess which has locally recessing the center axis C ₁ side. _{The central axis C 1} of the silicon carbide single crystal ingot 101 means an axis that passes through the center of the crystal growth plane 102a of the silicon carbide seed crystal and extends in a direction orthogonal to the crystal growth plane 102a. In offset direction S, of the outer peripheral portion of the silicon carbide ingot 101, defined from the center axis C ₁ end S ₁ farthest portion on the downstream _side, the farthest portion on the upstream side and the end portion S _2.

As shown on the lower side of FIG. 1, the necking portion 101c is recessed inward from the position of the outer peripheral portion of the crystal growth surface 102a of the silicon carbide seed crystal 102 in a plan view from the crystal growth direction D. It is preferable that the depth d _{1 of the} dent is maximum at the end portion S ₁ on the downstream side of the offset and becomes smaller as it approaches the upstream side of the offset. The depth d _{1 of the} dent is preferably 1 mm or more, preferably 1 mm or more and 5 mm or less. If d ₁ is less than 1 mm, dislocation sweeping may be insufficient, and if it is larger than 5 mm, the diameter of the ingot will be significantly reduced. Will be reduced. The shape of the crystal growth surface 102a is preferably circular, but may be polygonal.

At least a part on the upstream side of the offset does not have a necking portion, and this portion protrudes outward from the position of the outer peripheral portion of the crystal growth surface 102a or is recessed inward within a range of less than 1 mm in the plan view. I'm out.

The necking portion 101c is preferably located at _{a distance d 2} within about 10 mm from the crystal growth surface 102a of the silicon carbide seed crystal. In general, dislocations decrease as the distance from the seed crystal increases. Therefore, in order to obtain a high-quality wafer having a large diameter, it is preferable to provide the necking portion with a diameter reduction at a position close to the seed crystal.

In the cross-sectional view (upper side) of FIG. 1, the case where the necking portion 101c is recessed in a V shape with respect to the side wall surface 102a of the silicon carbide single crystal ingot is illustrated. There is no limitation. For example, the bottom surface of the concave portion constituting the necking portion 101c may be flat or curved.

The silicon carbide single crystal ingot formed by the conventional method expands as the distance from the silicon carbide seed crystal increases so that the area of the cross section perpendicular to the crystal growth direction is larger than the area of the crystal growth plane of the silicon carbide seed crystal. It becomes a shape with a diameter. On the other hand, in the silicon carbide single crystal ingot 101 of the present embodiment, as shown in the plan view (lower side) of FIG. 1, the diameter is locally reduced at the position P of the necking portion 101c, and the crystal growth direction D The area of the cross section 101b perpendicular to is smaller than the area of the crystal growth surface 102a of the silicon carbide seed crystal. The diameter of the silicon carbide single crystal ingot 101 increases as it moves away from the necking portion 101c in the crystal growth direction D.

The center O'of the cross section 101b of the silicon carbide single crystal ingot in the necking portion does not overlap with the center O of the crystal growth surface 102a of the silicon carbide seed crystal in the plan view of the crystal growth direction D. The center O'generally means the position of the center of gravity of the portion (small thickness portion) 101d near the cross section 101b, and the center O means the position of the center of gravity of the portion (small thickness portion) 102b near the crystal growth surface 102a. ing. It is preferable that the position of the center O'is offset to the upstream side of the offset by about 1 mm or more with respect to the position of the center O.

On the upstream side of the offset, the through-spiral dislocations (TSD: indicated by a broken line) inherent in the silicon carbide seed crystal 102 before crystal growth grow together with the silicon carbide single crystal, and the facet portion of the silicon carbide single crystal ingot 101. It has been extended to.

On the other hand, in the outer peripheral portion other than the offset upstream side, the TSD grown from the silicon carbide seed crystal 102 is swept out (removed) at the position P of the necking portion 101c, and the region having less TSD as compared with the offset upstream side. Is formed.

There are various polymorphs having different laminated structures such as 3C, 4H, 6H, and 15R in the silicon carbide member. When the silicon carbide member is used as the wafer of the device, it is preferable to select the silicon carbide member composed of a single polymorph. However, since there is almost no difference in Gibbs free energy between these polymorphs, a plurality of different polymorphs may be mixed in the silicon carbide member.

As one of the means for suppressing the mixing of heterogeneous polymorphs, there is a method of using a seed crystal in which the crystal plane is turned off (tilted) by 0 to 10 ° in the <11-20> direction from the C plane or the Si plane. In this method, the polymorph of the seed crystal is easily inherited because the step of determining the polymorph type is exposed on the surface.

In order to suppress the generation of heterogeneous polymorphs in the manufacturing process of the silicon carbide single crystal, the {0001} plane (c plane) was turned off by 10 ° in the <11-20> direction in the growth of the silicon carbide single crystal. Things are often used. Further, in order to suppress the occurrence of cracks and dislocations of the crystals constituting the ingot, it is preferable to reduce the temperature difference between the center and the outer periphery of the ingot, and the shape of the ingot after growth is the shape of the center and the outer periphery. It is preferable that the difference in the amount of growth is a convex shape of 8 mm or less. However, when such a convex ingot is grown, facets on the C-plane or Si-plane are formed on the off-upstream side. Since step flow growth is not possible within the facet plane, heterogeneous polymorphism is likely to occur.

By conventional necking as disclosed in Patent Document 1, dislocations in the outer peripheral portion of the ingot are mainly swept out of the crystal, so that the quality of the ingot can be improved, but facets are easily formed. Spiral dislocations inherent in the upstream side are also swept out. If there is a spiral dislocation on the facet, a step is formed there, which has the effect of making the polymorph more stable. This effect is impaired.

In the silicon carbide single crystal ingot according to the present embodiment, by providing a region that does not neck only on the off upstream side in the growth process, spiral dislocations are likely to exist on the facet during growth, and heterogeneous polymorphs are less likely to occur. Become. Since the dislocations inherent in other portions are swept out by necking, the grown silicon carbide single crystal ingot is of high quality. That is, according to the present embodiment, it is possible to achieve both high quality by sweeping dislocations and suppression of heterogeneous polymorphism by maintaining spiral dislocations in the facet portion, which was difficult in the prior art.

(Manufacturing method of silicon carbide single crystal)
FIG. 2 is a vertical sectional view of a manufacturing apparatus 10 used for manufacturing a silicon carbide single crystal according to an embodiment of the present invention, and shows a state in which a silicon carbide seed crystal 102 is arranged. The manufacturing apparatus 10 includes at least a crucible 11, a raw material (silicon carbide raw material) 12 arranged on one side of the crucible 11 (lower side in FIG. 2), and the other side in the crucible 11 (upper side in FIG. 2). ), The pedestal (graphite member) 13 of the silicon carbide seed crystal (seed) 102, the tubular guide member 14 for guiding the raw material gas, and the coil 15 surrounding the outer wall of the crucible 11 are provided. The illustration of the depth portion of the coil 15 is omitted.

The guide member 14 is arranged so that one opening 14a faces the silicon carbide seed crystal 102 side and the other opening 14b faces the silicon carbide raw material 12 side. The inner diameter of one opening 14a of the guide member is about the same as the diameter of the crystal growth surface 102a of the silicon carbide seed crystal, specifically, 0.9 times or more and 1.0 times or less the diameter of the crystal growth surface 102a. It is preferable to have.

The guide member 14 has a side wall so that the diameter of the guide member 14 is reduced from the raw material 12 side to the pedestal 13 side from the viewpoint of inducing the raw material gas widely distributed in the crucible 11 so as to collect on the silicon carbide seed crystal 102. It preferably has a tapered shape. The guide angle (taper angle) between the central axis C ₂ of the side wall and the guide member 14 of the member 14 theta, is preferably 5 ° to 60 °. If the angle θ is smaller than 5 °, the diameter of the ingot hardly expands, which makes it difficult to obtain a large-diameter wafer, which is not preferable. Further, when the angle θ is larger than 60 °, the expansion of the diameter of the ingot is promoted, but it becomes difficult to keep the temperature difference between the central portion and the outer peripheral portion of the growing ingot small, and cracks and dislocations of the basal plane occur. Is not preferable because it tends to occur.

The manufacturing process of the silicon carbide single crystal using the manufacturing apparatus 10 will be described. 3 (a) is, in a stage before performing the crystal growth, in the manufacturing apparatus 10 of a silicon carbide single crystal 2 is an enlarged view of a region R ₁ in the vicinity of the silicon carbide seed crystal 102. First, the silicon carbide seed crystal 102 is placed in the crucible 11 in a state of being attached to the pedestal 13.

At this time, the crystal growth surface 102a, the position O "through which a central axis C ₂ of the guide member 14, than to be shifted to the offset position upstream of the center O, adjust the position of the silicon carbide seed crystal 102.

Further, in the plan view of the crystal growth direction D, the center O of the crystal growth surface 102a is separated from the center of the opening 14a of the guide member within a range of 1 mm or more and 5 mm or less, that is, the position O and the position O ”. It is preferable to adjust the position of the silicon carbide seed crystal 102 with respect to the guide member 14 so that the distance d _{3 from the guide member 14 is 1 mm or more and 5 mm or less.}

Further, in the crystal growth direction D, the crystal growth surface 102a is in contact with the opening (opening surface) 14a of the guide member, or is separated from the opening 14a of the guide member within a range of 5 mm or less with respect to the guide member 14. It is preferable to adjust the position of the silicon carbide seed crystal 102. That is, it is preferable to adjust the position of the silicon carbide seed crystal 102 with respect to the guide member 14 so that _{the distance d 4} between the crystal growth surface 102a and the opening 14a is 5 mm or less.

3 (b) is in the stage of performing crystal growth, in the manufacturing apparatus 10 of a silicon carbide single crystal 2 is an enlarged view of a region R ₁ in the vicinity of the silicon carbide seed crystal 102. After arranging each component as described above, an alternating current is applied to the coil 15 to heat the crucible 11. As a result, a raw material gas (sublimation gas) is generated from the raw material 12, and the raw material gas is supplied to the silicon carbide seed crystal 102 installed on the pedestal 13 along the guide member 14. By supplying the raw material gas to the silicon carbide seed crystal 102, the silicon carbide single crystal ingot 101 grows on the main surface of the silicon carbide seed crystal 102. The crystal growth surface 102a of the silicon carbide seed crystal is preferably a carbon surface or a surface having an off angle of 10 ° or less from the carbon surface.

Next, the obtained silicon carbide single crystal ingot 101 is sliced to prepare a silicon carbide single crystal wafer. Slices perpendicular to <0001> or in a direction with an off angle of 0 to 10 ° to prepare a wafer having a plane parallel to the c-plane or having a plane with an off-angle of 0 to 10 ° from the c-plane. The off angle may be provided in any direction. For example, when it is provided in the <11-20> direction, the angle formed by the main surface and the <11-20> direction is the offset angle. The surface of the wafer may be mirror-processed on the (0001) surface side, that is, the Si surface side. The Si surface is a surface that normally undergoes epitaxial growth.

As described above, in the process of forming the silicon carbide single crystal ingot 101, the TSD contained in the silicon carbide seed crystal 102 propagates to the facet portion at the outer peripheral portion on the upstream side of the offset, but the outer peripheral portion on the side other than the upstream side of the offset. Then, it is swept out by the necking portion 101c. Therefore, according to the method for producing a silicon carbide single crystal according to the present embodiment, the number of internal TSDs is reduced within the range in which the generation of heterogeneous polymorphs on the upstream side of the offset is suppressed and high quality can be maintained. Crystals can be produced.

In the present embodiment, an example in which the sublimation method is applied as a method for producing a silicon carbide single crystal has been described, but a vapor phase is used on a silicon carbide seed crystal using an apparatus having a configuration corresponding to the guide member. A gas method for growing from silicon can also be applied.

Hereinafter, the effects of the present invention will be further clarified by examples. The present invention is not limited to the following examples, and can be appropriately modified and implemented without changing the gist thereof.

(Example 1)
The method for producing a silicon carbide single crystal according to the above embodiment was carried out. FIG. 4 is an enlarged photograph of the necking portion on the downstream side of the offset in the silicon carbide single crystal ingot obtained in the manufacturing process. Enlarged portion corresponds to a portion of the region R ₂ shown in FIG. 3, as in the above embodiment, with respect to the central axis of the guide member, the center of the silicon carbide seed crystal is shifted in the offset downstream.

As the silicon carbide seed crystal, a crystal having a crystal growth surface having a diameter of about 160 mm and a thickness of about 2 mm was used. As the guide member, a member having an inner diameter of about 158 mm in the opening on the silicon carbide seed crystal side and a taper angle of about 15 ° on the side wall was used. _{When arranging the pedestal of the silicon carbide seed crystal, the distance d 3} between the center of the crystal growth surface of the silicon carbide seed crystal and the center of the opening of the guide member was set to about 1 mm in a plan view in the crystal growth direction. .. Furthermore, the crystal growth surface of the silicon carbide seed crystal, the distance d ₄ between the opening portion of the guide member, was about 0.5 mm.

As described above, it was confirmed that the necking portion was formed as shown in FIG. 4 by performing the sublimation method after adjusting the position of the silicon carbide seed crystal with respect to the guide member. In the necking portion, the depth of the recess toward the central axis side (left side) became maximum at a position where _{the distance d 2 from the crystal growth surface was about 4 mm.} The depth d _{1 of the} dent was about 2 mm, and the center position of the crystal growth surface was about the same as the distance deviated from the center position of the opening of the guide member in the plan view in the crystal growth direction.

Observation by X-ray topography revealed that the propagation of TSD from the silicon carbide seed crystal side (upper side) was interrupted at the position of the necking part and did not exist in the part grown after the necking part. .. From this result, it was possible to confirm that the TSD was swept out in the necking portion.

The present invention can be utilized when growing a SiC single crystal by a sublimation method or the like, reduces the occurrence of through-spiral dislocations that affect the characteristics of a device using a SiC single crystal, and greatly contributes to improvement in yield. It provides a means of doing so.

101 ... Silicon carbide single crystal ingot 101a ... Side wall surface 101b ... Cross section 101c ... Necking portion 101d ... Part near the cross section 102 ... Silicon carbide seed crystal 102a ... Crystal growth surface 102b ... Part 10 near the crystal growth surface 10 ... Manufacturing equipment 11 ... Rabbit 12 ... Raw material 13 ... Pedestal 14 ... Guide members 14a, 14b ... Opening 15 ... Coil C ₁ , C ₂ ... Central axis D ... Crystal growth direction d ₁ , d ₂ , d ₃ , d ₄ ... Distance O, O', O ", P ... Position R ₁ , R _{2 ...}・ ・ Region S ・ ・ ・ Offset direction S ₁ , S ₂・ ・ ・ End θ ・ ・ ・ Angle

Claims (6)

A silicon carbide single crystal ingot formed on the main surface having an offset angle with respect to the c-plane among the surfaces of the silicon carbide seed crystal.
At a predetermined position in the crystal growth direction of the silicon carbide single crystal ingot, the central axis side of the silicon carbide single crystal ingot is on the outer peripheral portion including at least a part on the offset upstream side and at least a part on the offset downstream side. A silicon carbide single crystal ingot characterized by having a dented necking portion. The silicon carbide single crystal ingot according to claim 1, wherein the necking portion is at a distance within 10 mm from the silicon carbide seed crystal. The center of the cross section of the silicon carbide single crystal ingot having the necking portion and perpendicular to the crystal growth direction is 1 mm or more away from the center of the crystal growth surface of the silicon carbide seed crystal in the plan view of the crystal growth direction. The silicon carbide single crystal ingot according to any one of claims 1 or 2, wherein the ingot is a single crystal. A method for producing a silicon carbide single crystal.
Place the silicon carbide raw material on one side of the crucible,
A silicon carbide seed crystal and a tubular guide member having an opening on one side facing the silicon carbide seed crystal are arranged on the other side of the crucible.
A sublimation gas is supplied to the silicon carbide seed crystal in a state where the center of the crystal growth surface of the silicon carbide seed crystal is shifted from the center of the opening of the guide member in a plan view in the crystal growth direction.
In a plan view in the crystal growth direction, the carbide with respect to the guide member is such that the center of the crystal growth surface of the silicon carbide seed crystal is separated from the center of the opening of the guide member within a range of 1 mm or more and 5 mm or less. A method for producing a silicon carbide single crystal, which comprises adjusting the position of a silicon seed crystal. A method for producing a silicon carbide single crystal.
Place the silicon carbide material on one side of the pit,
A silicon carbide seed crystal and a tubular guide member having an opening on one side facing the silicon carbide seed crystal are arranged on the other side of the crucible.
A sublimation gas is supplied to the silicon carbide seed crystal in a state where the center of the crystal growth surface of the silicon carbide seed crystal is shifted from the center of the opening of the guide member in a plan view in the crystal growth direction.
Adjusting the position of the silicon carbide seed crystal with respect to the guide member so that the crystal growth surface of the silicon carbide seed crystal is separated from the opening of the guide member within a range of 5 mm or less in the crystal growth direction. method for producing a coal of silicon single crystal you characterized. The carbonization of the guide member so that the center of the crystal growth surface of the silicon carbide seed crystal is separated from the center of the opening of the guide member within a range of 1 mm or more and 5 mm or less in a plan view in the crystal growth direction. The method for producing a silicon carbide single crystal according to claim 5 , wherein the position of the silicon seed crystal is adjusted.

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