Sic single crystal, sic substrate, and sic epitaxial wafer

Abstract

To provide an SiC single crystal capable of reducing basal plane dislocation density.SOLUTION: In the SiC single crystal according to the present embodiment, all of the lattice planes measured along each of the first straight line, the second straight line, the third straight line, the fourth straight line, the fifth straight line, and the sixth straight line are curved in a convex shape. In the lattice planes measured along each of the first straight line, the second straight line, the third straight line, the fourth straight line, the fifth straight line, and the sixth straight line, the center is on the C plane side from the end portion of the lattice plane measured along each of the straight lines. Each of the first straight line, the second straight line, the third straight line, the fourth straight line, the fifth straight line, and the sixth straight line is a straight line that passes through the center in a plan view from the thickness direction and is inclined by 30 ° with respect to the center.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a SiC single crystal, a SiC substrate, and a SiC epitaxial wafer. [Background technology]

[0002] Silicon carbide (SiC) has an electric breakdown field one order of magnitude larger than silicon (Si) and a band gap three times larger. Silicon carbide (SiC) also has other properties, such as a thermal conductivity three times higher than silicon (Si). Therefore, silicon carbide (SiC) is expected to be applied to power devices, high-frequency devices, and other applications. Furthermore, devices using silicon carbide (SiC) can operate at high temperatures of 150°C or higher. For this reason, SiC epitaxial wafers have recently come to be used in the above-mentioned semiconductor devices.

[0003] SiC epitaxial wafers are obtained by stacking a SiC epitaxial layer on the surface of a SiC substrate. Hereinafter, the substrate before the SiC epitaxial layer is stacked will be referred to as the SiC substrate, and the substrate after the SiC epitaxial layer is stacked will be referred to as the SiC epitaxial wafer. SiC substrates are cut from SiC ingots. SiC ingots are formed by growing a SiC single crystal on a seed crystal.

[0004] High-quality SiC single crystals with fewer defects and dislocations are required. Patent Document 1 describes that there is a correlation between the amount of curvature of the lattice plane of a SiC single crystal and the density of basal plane dislocations (BPDs). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-26373 Summary of the Invention [Problem to be solved by the invention]

[0006] The basal plane dislocation (BPD) density changes as crystal growth progresses. For example, when a SiC single crystal is grown on the C-face, the basal plane dislocation density differs between the Si-face and the C-face. If the basal plane dislocation density on the C-face can be made lower than that on the Si-face, the SiC substrate cut from near the C-face will be of high quality with a low basal plane dislocation density.

[0007] The present disclosure has been made in view of the above problems, and has an object to provide a SiC single crystal that can reduce the basal plane dislocation density in the C-plane. [Means for solving the problem]

[0008] After extensive research, the inventors discovered that the warpage of the lattice plane of a SiC single crystal affects changes in the basal plane dislocation density and threading dislocation density within the SiC single crystal. The warpage of the lattice plane of a SiC single crystal changes due to factors such as internal stresses that arise during crystal growth and cooling of the SiC single crystal, and therefore does not necessarily coincide with the external shape of the SiC single crystal (e.g., the final shape of the crystal growth surface of the SiC single crystal). In other words, the warpage of the SiC lattice plane cannot be determined from the external shape of the SiC single crystal. Simply controlling the external shape of the SiC single crystal does not fully control the warpage of the SiC lattice plane, and therefore the basal plane dislocation density and threading dislocation density in the C-plane cannot be sufficiently reduced. The present disclosure has discovered that the lattice plane warpage of a SiC single crystal can be controlled to reduce the basal plane dislocation density and threading dislocation density in the C-plane. In other words, the present disclosure provides the following means to solve the above problems.

[0009] (1) In a SiC single crystal according to a first aspect, all of the lattice planes measured along the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line are curved in a convex shape. In the lattice planes measured along the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, the centers are located closer to the C-plane side than the ends of the lattice planes measured along the respective lines. The first line is a line passing through the center when viewed in a plan view from the thickness direction. The second line is a line passing through the center and inclined at 30° with respect to the first line with respect to the center. The third line is a line passing through the center and inclined at 60° with respect to the first line with respect to the center. The fourth line is a line passing through the center and inclined at 90° with respect to the first line with respect to the center. The fifth line is a line passing through the center and inclined at 120° with respect to the first line with respect to the center. The sixth straight line passes through the center and is inclined at 150° with respect to the first straight line with respect to the center.

[0010] (2) In the SiC single crystal according to the above aspect, the main surface may have an offset angle with respect to the (0001) plane, in which case the first straight line is a straight line extending in the <11-20> direction.

[0011] (3) In the SiC single crystal according to the above aspect, when the diameter in a planar view from the thickness direction is d, the maximum diffraction peak angle of the (0004) plane at the center is ω0, and the maximum diffraction peak angle of the (0004) plane at a measurement point d / 3 away from the center is ω1, in the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, (ω1-ω0) / (d / 3)<-2.00×10 -6 may be satisfied.

[0012] (4) In the SiC single crystal according to the above aspect, in the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, (ω1-ω0) / (d / 3)<-3.00×10 -6 may be satisfied.

[0013] (5) In the SiC single crystal according to the above aspect, in the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, (ω1-ω0) / (d / 3)<-4.00×10 -6 may be satisfied.

[0014] (6) In the SiC single crystal according to the above aspect, when the diameter in a plan view from the thickness direction is d, in the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, the half-width of the maximum diffraction peak of the (0004) plane at a measurement point d / 3 away from the center is 5.20 × 10 -2 It may be less than.

[0015] (7) In the SiC single crystal according to the above aspect, in the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, the half-width of the maximum diffraction peak of the (0004) plane at a measurement point d / 3 away from the center is 4.80 × 10 -2 It may be less than.

[0016] (8) In the SiC single crystal according to the above aspect, in the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, the half-width of the maximum diffraction peak of the (0004) plane at a measurement point d / 3 away from the center is 4.40 × 10 -2 It may be less than.

[0017] (9) The SiC single crystal according to the above aspect may satisfy (BPD0-BPD1) / BPD0>64%, where BPD0 is the basal plane dislocation density on the Si-plane and BPD1 is the basal plane dislocation density on the C-plane.

[0018] (10) The SiC single crystal according to the above aspect may satisfy (TSD0-TSD1) / TSD0>48.2%, where TSD0 is the threading screw dislocation density on the Si-plane and TSD1 is the threading screw dislocation density on the C-plane.

[0019] (11) The SiC single crystal according to the above aspect may satisfy (BPD0-BPD1) / (BPD0×T)>1% / mm and (TSD0-TSD1) / (TSD0×T)>1% / mm, where BPD0 is the basal plane dislocation density on the Si-plane, BPD1 is the basal plane dislocation density on the C-plane, TSD0 is the threading screw dislocation density on the Si-plane, TSD1 is the threading screw dislocation density on the C-plane, and T is the crystal length in the thickness direction.

[0020] (12) The SiC single crystal according to the above aspect may satisfy (BPD0-BPD1) / (BPD0×T)>2% / mm and (TSD0-TSD1) / (TSD0×T)>2% / mm.

[0021] (13) The SiC single crystal according to the above aspect may satisfy (BPD0-BPD1) / (BPD0×T)>3% / mm and (TSD0-TSD1) / (TSD0×T)>3% / mm.

[0022] (14) The SiC single crystal according to the above aspect may have a diameter of 145 mm or more when viewed in a plan view in the thickness direction.

[0023] (15) The SiC single crystal according to the above aspect may have a diameter of 195 mm or more when viewed in a plan view in the thickness direction.

[0024] (16) The SiC single crystal according to the above aspect may have a diameter of 295 mm or more when viewed in a plan view in the thickness direction.

[0025] (17) The SiC single crystal according to the above aspect has a basal plane dislocation density in the C-plane of 500 / cm 2 The following is also acceptable.

[0026] (18) The SiC single crystal according to the above aspect has a threading screw dislocation density on the C-plane of 300 / cm 2 The following is also acceptable.

[0027] (19) The SiC single crystal according to the above aspect has a defect density of 4000 / cm on the C-plane. 2 The following is also acceptable.

[0028] (20) A SiC substrate according to a second aspect includes the SiC single crystal according to the above aspect.

[0029] (21) A SiC epitaxial wafer according to a third aspect includes the SiC substrate according to the above aspect and an epitaxial layer stacked on one surface of the SiC substrate. [Effects of the Invention]

[0030] The SiC single crystal according to the above embodiment can reduce the basal plane dislocation density in the C-plane. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a perspective view of a SiC single crystal according to an embodiment of the present invention. [Figure 2] 1 is a plan view of a SiC single crystal according to an embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view of a characteristic portion of the SiC single crystal according to the present embodiment. [Figure 4] FIG. 2 is a perspective view of an example of a lattice plane of the SiC single crystal according to the present embodiment. [Figure 5] FIG. 2 is a perspective view of an example of a lattice plane of a SiC single crystal according to a first comparative example. [Figure 6] FIG. 10 is a perspective view of an example of a lattice plane of a SiC single crystal according to a second comparative example. [Figure 7] FIG. 2 is a cross-sectional view of the SiC single crystal manufacturing apparatus according to the present embodiment before crystal growth. [Figure 8] FIG. 2 is a cross-sectional view of a holding member of the SiC single crystal manufacturing apparatus according to the present embodiment. [Figure 9]FIG. 2 is a cross-sectional view of the SiC single crystal manufacturing apparatus according to the present embodiment during crystal growth. [Figure 10] FIG. 10 is a cross-sectional view of another example of a holding member of the SiC single crystal manufacturing apparatus according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] The SiC single crystal according to this embodiment will be described in detail below with reference to the drawings as appropriate. The drawings used in the following description may show characteristic portions enlarged for the sake of clarity, and the dimensional ratios of each component may differ from the actual ones. The materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto. Appropriate modifications can be made within the scope of the present invention.

[0033] In this specification, individual orientations are indicated by [], collective orientations by <>, individual planes by (), and collective planes by {}. For negative indices, a "-" (bar) is placed before the number in crystallography, but in this specification, a negative sign is placed before the number.

[0034] First, let us define the direction. The thickness direction (crystal growth direction) of the SiC single crystal is the Z direction. The Z direction is defined as follows: <0001> It can be a direction, <0001> The Z direction may be tilted by an offset angle relative to the Z direction. For example, the +Z direction is the [000-1] direction, and the -Z direction is the

[0001] direction. With the center of the SiC single crystal in the thickness direction as the reference, the main surface in the [000-1] direction is the C-plane, and the main surface in the

[0001] direction is the Si-plane. One direction of a plane perpendicular to the Z direction is the X direction. The X direction is, for example, the <11-20> direction. For example, with the center as the reference, the -X direction is the [11-20] direction, and the +X direction is the [-1-120] direction. The -X direction is the upstream offset side in the case of offset growth, and the +X direction is the downstream offset side in the case of offset growth. Furthermore, in a plane perpendicular to the Z direction, the direction perpendicular to the X direction is the Y direction. The Y direction is, for example, the <1-100> direction. For example, with the center as the reference, the +Y direction is the [1-100] direction and the -Y direction is the [-1100] direction.

[0035] FIG. 1 is a cross-sectional view of a SiC single crystal 1 according to this embodiment. The SiC single crystal 1 is made of, for example, n-type SiC. The polytype of the SiC single crystal 1 is not particularly limited and may be any of 2H, 3C, 4H, and 6H. The SiC single crystal 1 is, for example, 4H—SiC.

[0036] The SiC single crystal 1 has an Si-face 1A and a C-face 1B. The Si-face 1A and the C-face 1B are both end faces of the SiC single crystal 1 in the Z direction. The SiC single crystal 1 grows on an SiC seed crystal. During crystal growth, the Si-face 1A is often positioned on the SiC seed crystal side, and the C-face 1B becomes the crystal growth surface. The Si-face is the (0001) plane or a plane tilted by an offset angle with respect to the (0001) plane. The C-face is the (000-1) plane or a plane tilted by an offset angle with respect to the (000-1) plane. In other words, the main surface (Si-face or C-face) may or may not have an offset angle with respect to the (0001) plane or the (000-1) plane.

[0037] The offset angle is the angle between the (0004) plane and a plane perpendicular to the Z direction, which is the thickness direction of the SiC single crystal 1. The crystal growth plane of the SiC single crystal 1 may have a portion in the <11-20> direction that has an offset angle with respect to the (0004) plane. When the crystal growth plane has an offset angle with respect to the (0004) plane, the generation of heterogeneous polymorphs can be suppressed. The offset angle is, for example, more than 0° and not more than 10°, preferably 0.1° to 8°, more preferably 3.5° to 4.5°, and even more preferably 4°.

[0038] The plane of the SiC single crystal 1 that is orthogonal to the Z direction does not need to have an offset angle with respect to the (0004) plane. In some cases, the SiC single crystal 1 is produced (just-plane growth) using a SiC seed crystal that does not have an offset angle with respect to the (0004) plane ({0001} plane).

[0039] The crystal length T of the SiC single crystal 1 in the Z direction is, for example, 10 mm or more, preferably 20 mm or more, more preferably 30 mm or more, more preferably 40 mm or more, and particularly preferably 50 mm or more. The crystal length T of the SiC single crystal 1 in the Z direction is preferably, for example, 300 mm or less. The crystal length T of the SiC single crystal 1 in the Z direction is the longest length between the Si face 1A and the C face 1B in the Z direction. The longer the crystal length T of the SiC single crystal 1 in the Z direction, the more SiC substrates can be obtained. Furthermore, the longer the crystal length T of the SiC single crystal 1 in the Z direction, the more the lattice planes can be prevented from flattening when the SiC single crystal 1 is cooled from the high-temperature environment used during crystal growth, and the more the curvature of the lattice planes can be maintained.

[0040] 2 is a plan view of SiC single crystal 1 according to this embodiment, viewed from the Z direction. The shape of SiC single crystal 1 in plan view is substantially circular.

[0041] The diameter d of the SiC single crystal 1 is, for example, 145 mm or more, preferably 149 mm or more. The diameter d of the SiC single crystal 1 is preferably 155 mm or less, more preferably 151 mm or less. The diameter d of the SiC single crystal 1 may be, for example, 195 mm or more, preferably 199 mm or more. The diameter d of the SiC single crystal 1 may be preferably 205 mm or less, more preferably 201 mm or less. The diameter d of the SiC single crystal 1 may be 295 mm or more, preferably 299 mm or more. The diameter d of the SiC single crystal 1 may be 305 mm or less, preferably 301 mm or less. Here, the diameter d of the SiC single crystal 1 is the minimum diameter of the SiC single crystal 1 and corresponds to the minimum diameter of a obtainable SiC substrate. For example, when the diameter of the SiC single crystal 1 expands from the Si-face toward the C-face, the diameter of the Si-face corresponds to the diameter d of the SiC single crystal.

[0042] The SiC single crystal 1 is a compound of Si and C, and has equivalent atomic planes arranged at equal intervals. These atomic planes are called lattice planes. For example, FIG. 3 is a cross-sectional view of a characteristic portion of the SiC single crystal 1 according to this embodiment. FIG. 3 is a cross-sectional view of the SiC single crystal 1 cut along a line extending in the <11-20> direction (first line L1 in FIG. 2). The lattice plane S1 is formed by atoms A constituting the SiC single crystal 1. The lattice plane S1 of the SiC single crystal 1 shown in FIG. 3 is curved in a convex shape toward the C-plane 1B.

[0043] The shape of the lattice plane S1 can be measured by X-ray diffraction (XRD). The lattice plane to be measured is determined depending on the measurement direction. If the measurement direction is [hkil], the measurement plane must satisfy the relationship (mh mk mi n). Here, m is an integer greater than or equal to 0, and n is a natural number. For example, when measuring a lattice plane in the [11-20] direction, the (0004) plane is selected with m = 0 and n = 4, and the (22-416) plane is selected with m = 2 and n = 16. On the other hand, when measuring a lattice plane in the [1-100] direction, the (0004) plane is selected with m = 0 and n = 4, and the (3-3016) plane is selected with m = 3 and n = 16. In other words, the measurement plane may differ depending on the measurement direction. By satisfying the above relationship, it is possible to prevent lattice curvature in the a-plane or m-plane direction, which has little effect on crystal growth, from being mistaken for lattice curvature in the c-plane direction.

[0044] The lattice surface S1 measured along each of the first line L1, second line L2, third line L3, fourth line L4, fifth line L5, and sixth line L6 shown in Figure 2 is curved in a convex shape. In the lattice surface S1 measured along each of the first line L1, second line L2, third line L3, fourth line L4, fifth line L5, and sixth line L6, the center C is located closer to the C-plane 1B than the end of the lattice surface S1 measured along each line. In other words, the lattice surface S1 measured along each line is curved so that the center is convex toward the C-plane.

[0045] X-ray diffraction measurements are performed for each of the first line L1, the second line L2, the third line L3, the fourth line L4, the fifth line L5, and the sixth line L6. When the crystal length T of the SiC single crystal 1 to be measured is 500 μm or less, it is preferable to vacuum-suck the SiC single crystal 1 to the measurement stage to eliminate the influence of warping of the SiC single crystal 1. The first line L1 is a line passing through the center C when viewed from above in the Z direction. When the SiC single crystal 1 has an offset angle, the first line L1 is a line extending in the <11-20> direction. The second line L2 is a line passing through the center C and inclined at 30° with respect to the first line with respect to the center C. The third line L3 is a line passing through the center C and inclined at 60° with respect to the first line with respect to the center C. The second line L2 is a line passing through the center C and inclined at 90° with respect to the first line with respect to the center C. The second straight line L2 passes through the center C and is inclined at 120° with respect to the first straight line with the center C as the reference. The second straight line L2 passes through the center C and is inclined at 150° with respect to the first straight line with the center C as the reference. In Figure 2, the clockwise direction is the positive direction of rotation.

[0046] X-ray diffraction is measured at three points on each line: the center, the first measurement point, and the second measurement point. On the first line L1, X-ray diffraction measurements are performed at the center C, the first measurement point p11, and the second measurement point p12. On the second line L2, X-ray diffraction measurements are performed at the center C, the first measurement point p21, and the second measurement point p22. On the third line L3, X-ray diffraction measurements are performed at the center C, the first measurement point p31, and the second measurement point p32. On the fourth line L4, X-ray diffraction measurements are performed at the center C, the first measurement point p41, and the second measurement point p42. On the fifth line L5, X-ray diffraction measurements are performed at the center C, the first measurement point p51, and the second measurement point p52. On the sixth line L6, X-ray diffraction measurements are performed at the center C, the first measurement point p61, and the second measurement point p62.

[0047] The first and second measurement points are each a point d / 3 away from the center C. For example, if the SiC single crystal 1 is grown by offset, the point in the +X direction is the first measurement point, and the point in the -X direction is the second measurement point. However, because the fourth line L4 is perpendicular to the offset direction, the point d / 3 away from the center C in the -Y direction is the first measurement point p41, and the point d / 3 away from the center C in the +Y direction is the second measurement point p42. If the SiC single crystal 1 is not grown by offset, the +X direction and the -X direction are equivalent, and the +Y direction and the -Y direction are equivalent. Therefore, if the SiC single crystal 1 is not grown by offset, the first and second measurement points are not distinguished.

[0048] When the lattice plane S1 is curved, the diffraction direction of the X-rays changes, and the position of the peak angle (ω angle) of the diffraction peak in the X-ray diffraction image obtained at the center, the first measurement point, and the second measurement point varies. From the positional variation of the peak angle of this diffraction peak, the curvature direction of the lattice plane S1 along each straight line can be confirmed.

[0049] FIG. 4 is a perspective view of an example of a lattice plane S1 of a SiC single crystal 1 according to this embodiment. The lattice plane S1 shown in FIG. 4 has a mountain shape. The center of the lattice plane S1 shown in FIG. 4 is curved in a convex shape from the outer peripheral edge toward the C-plane 1B. The center of the lattice plane S1 is located closer to the C-plane 1B than the outer peripheral portion. The center of the lattice plane S1 is curved in a direction away from the Si-plane 1A. The lattice plane S1 is curved in a convex shape toward the C-plane regardless of which direction it is cut in on the XY plane. That is, in the example shown in FIG. 4, the lattice plane S1 measured along each of the first line L1, the second line L2, the third line L3, the fourth line L4, the fifth line L5, and the sixth line L6 are all curved in a convex shape, satisfying the conditions for the SiC single crystal 1 according to this embodiment.

[0050] In contrast, Fig. 5 is a perspective view of a lattice plane S2 of a SiC single crystal according to a first comparative example. The lattice plane S2 shown in Fig. 5 has a potato chip (saddle) shape. The lattice plane S2 shown in Fig. 5 is curved in a convex shape with its center pointing toward the C-plane 1B in the X direction, but is curved in a concave shape with its center pointing away from the C-plane 1B in the Y direction. Therefore, when cut along the XZ plane, the lattice plane S2 is curved in a convex shape with its center pointing toward the C-plane, but when cut along the YZ plane, it is not curved in a convex shape with its center pointing toward the C-plane.

[0051] FIG. 6 is a perspective view of a lattice plane S3 of a SiC single crystal according to a second comparative example. The lattice plane S3 shown in FIG. 6 has a bowl-like shape. The lattice plane S3 shown in FIG. 6 has a center that is concavely curved in a direction away from the C-plane 1B relative to the outer peripheral edge. The center of the lattice plane S1 is located closer to the Si-plane 1A than the outer peripheral portion. The lattice plane S1 has a center that is curved in a direction away from the C-plane 1B. When cut in either direction on the XY plane, the lattice plane S3 is concavely curved in a direction away from the C-plane.

[0052] In the SiC single crystal 1 according to this embodiment, the X-ray diffraction results measured along the first line L1, the second line L2, the third line L3, the fourth line L4, the fifth line L5, and the sixth line L6 all satisfy (ω1-ω0) / (d / 3)<-2.00×10 -6 It is preferable to satisfy (ω1-ω0) / (d / 3)<-3.00×10 -6 It is more preferable that (ω1-ω0) / (d / 3)<-4.00×10 -6 It is more preferable that the following relationship is satisfied. d is the diameter of the SiC single crystal 1 when viewed in a plan view from the Z direction. ω0 is the maximum diffraction peak angle of the (0004) plane at the center C. ω1 is the maximum diffraction peak angle of the (0004) plane at the first measurement point. The larger this value, the more greatly the lattice plane S1 curves. The larger this value, the smaller the basal plane dislocation density on the C-plane 1B relative to the basal plane dislocation density on the Si-plane 1A. The X-ray diffraction results measured along each of the first line L1, second line L2, third line L3, fourth line L4, fifth line L5, and sixth line L6 all satisfy, for example, (ω1-ω0) / (d / 3)>-1.00×10-5 may be satisfied.

[0053] Furthermore, in the SiC single crystal 1 according to this embodiment, the X-ray diffraction results measured along the first line L1, the second line L2, the third line L3, the fourth line L4, the fifth line L5, and the sixth line L6 all satisfy the following relationship: (ω2-ω0) / (d / 3)<-2.00×10 -6 It is preferable to satisfy (ω2-ω0) / (d / 3)<-3.00×10 -6 It is more preferable to satisfy (ω2-ω0) / (d / 3)<-4.00×10 -6 It is more preferable that the following relation is satisfied. ω2 is the maximum diffraction peak angle of the (0004) plane at the second measurement point. The larger this value, the more greatly the lattice plane S1 curves. The larger this value, the smaller the basal plane dislocation density on the C-plane 1B relative to the basal plane dislocation density on the Si-plane 1A. The X-ray diffraction results measured along each of the first line L1, second line L2, third line L3, fourth line L4, fifth line L5, and sixth line L6 all satisfy the relation (ω2-ω0) / (d / 3)>-1.00×10 -5 may be satisfied.

[0054] In the X-ray diffraction results measured along the first line L1, the second line L2, the third line L3, the fourth line L4, the fifth line L5, and the sixth line L6, the half-width of the maximum diffraction peak of the (0004) plane at the first measurement point and the second measurement point was 5.20 × 10 -2 Preferably, it is less than 4.80 x 10 -2 More preferably, it is less than 4.40 x 10 -2 More preferably, it is less than 4.00 x 10 -2 It is particularly preferable that the half-width of the maximum diffraction peak in X-ray diffraction represents the crystallinity of the SiC single crystal 1. The narrower the half-width of the maximum diffraction peak, the higher the crystallinity of the SiC single crystal 1. The half-width of the maximum diffraction peak of the (0004) plane at the first measurement point and the second measurement point is, for example, 2.00 × 10 -2 It may be more than that.

[0055] The SiC single crystal 1 according to this embodiment preferably satisfies (BPD0 - BPD1) / BPD0 > 64%, more preferably satisfies (BPD0 - BPD1) / BPD0 > 70%, more preferably satisfies (BPD0 - BPD1) / BPD0 > 80%, more preferably satisfies (BPD0 - BPD1) / BPD0 > 90%, more preferably satisfies (BPD0 - BPD1) / BPD0 > 95%, and more preferably satisfies (BPD0 - BPD1) / BPD0 > 99%. BPD0 is the basal plane dislocation density (dislocations / cm) on the Si surface 1A. 2 ), and BPD1 is the basal plane dislocation density (number / cm) on the C-plane. 2 ) SiC single crystal 1 grows with Si-face 1A as the seed crystal side and C-face 1B as the crystal growth surface. Therefore, this value indicates the reduction rate of basal plane dislocations during crystal growth of SiC single crystal 1. The greater the reduction rate of basal plane dislocations in SiC single crystal 1, the higher the quality of the SiC substrate cut out from the vicinity of C-face 1B. SiC single crystal 1 according to this embodiment may satisfy (BPD0-BPD1) / BPD0<100%.

[0056] Furthermore, the SiC single crystal 1 according to this embodiment preferably satisfies (TSD0-TSD1) / TSD0>48.2%, more preferably satisfies (TSD0-TSD1) / TSD0>50%, more preferably satisfies (TSD0-TSD1) / TSD0>60%, more preferably satisfies (TSD0-TSD1) / TSD0>70%, more preferably satisfies (TSD0-TSD1) / TSD0>80%, more preferably satisfies (TSD0-TSD1) / TSD0>90%, more preferably satisfies (TSD0-TSD1) / TSD0>95%, and more preferably satisfies (TSD0-TSD1) / TSD0>99%. TSD0 is the threading screw dislocation density (number / cm) on the Si surface 1A. 2 ), and TSD1 is the threading screw dislocation density (number / cm) on the C-plane. 2) This value indicates the reduction rate of threading screw dislocations during crystal growth of the SiC single crystal 1. The greater the reduction rate of threading screw dislocations in the SiC single crystal 1, the higher the quality of the SiC substrate cut out from the vicinity of the C-plane 1B. The SiC single crystal 1 according to this embodiment may satisfy (TSD0-TSD1) / TSD0<100%.

[0057] Furthermore, the SiC single crystal 1 according to this embodiment preferably satisfies (BPD0 - BPD1) / (BPD0 x T) > 1% / mm and (TSD0 - TSD1) / (TSD0 x T) > 1% / mm. Furthermore, the SiC single crystal 1 according to this embodiment more preferably satisfies (BPD0 - BPD1) / (BPD0 x T) > 2% / mm and (TSD0 - TSD1) / (TSD0 x T) > 2% / mm. Furthermore, the SiC single crystal 1 according to this embodiment more preferably satisfies (BPD0 - BPD1) / (BPD0 x T) > 3% / mm and (TSD0 - TSD1) / (TSD0 x T) > 3% / mm. T is the crystal length of the SiC single crystal 1. (BPD0 - BPD1) / (BPD0 x T) represents the reduction rate of basal plane dislocations per unit length in the Z direction. (TSD0-TSD1) / (TSD0×T) represents the reduction rate of threading screw dislocations per unit length in the Z direction. Furthermore, SiC single crystal 1 according to this embodiment may satisfy (BPD0-BPD1) / (BPD0×T)<5% / mm, or may satisfy (TSD0-TSD1) / (TSD0×T)<10% / mm.

[0058] The basal plane dislocation density (BPD1) on the C-plane 1B of the SiC single crystal 1 is, for example, 500 / cm 2 The basal plane dislocation density (BPD1) on the C-plane 1B may be, for example, 400 / cm 2 Less than 300 pieces / cm is acceptable. 2 Less than 200 pieces / cm is acceptable. 2 Less than 100 pieces / cm is acceptable. 2 Less than 50 pieces / cm is acceptable. 2 The lower the basal plane dislocation density in the C-plane, the higher the quality of the SiC substrate that can be obtained.

[0059] The threading screw dislocation density (TSD1) on the C-plane 1B of the SiC single crystal 1 is, for example, 300 / cm 2 The threading screw dislocation density (TSD1) on the C-plane 1B may be, for example, 200 / cm 2 Less than 172 pieces / cm is also acceptable. 2 Less than 150 pieces / cm is acceptable. 2 Less than 100 pieces / cm is acceptable. 2 Less than 50 pieces / cm is acceptable. 2 The lower the threading screw dislocation density in the C-plane, the higher the quality of the SiC substrate that can be obtained.

[0060] The defect density (EPD) on the C-plane 1B of the SiC single crystal 1 is, for example, 4000 / cm 2 The defect density (EPD) on the C-plane 1B may be, for example, 3000 / cm 2 Less than 2000 pieces / cm is also acceptable. 2 Less than 1300 pieces / cm is also acceptable. 2 Less than 1000 pieces / cm is also acceptable. 2 Less than 500 pieces / cm is acceptable. 2 The lower the defect density in the C-plane, the higher the quality of the SiC substrate that can be obtained.

[0061] The basal plane dislocation density, threading screw dislocation density, and defect density on the C-face 1B of the SiC single crystal 1 may be measured by irradiating the C-face 1B with X-rays and performing reflection X-ray topography analysis. The C-face 1B may be polished before the measurement.

[0062] Next, a method for manufacturing SiC single crystal 1 according to this embodiment will be described. Figures 7 to 9 are diagrams for explaining a method for manufacturing SiC single crystal 1 according to this embodiment.

[0063] Manufacturing apparatus 100 includes, for example, crucible 10, holding member 11, heat insulator 20, heating member 30, and shielding members 41 and 42. Fig. 7 shows the state before crystal growth of SiC single crystal 1 begins.

[0064] Crucible 10 is made of, for example, graphite. Crucible 10 encloses a growth space. A SiC seed crystal 2 and a SiC raw material 3 are placed in the growth space of crucible 10. Gas sublimated from SiC raw material 3 recrystallizes on the surface of SiC seed crystal 2, resulting in crystal growth of SiC single crystal 1.

[0065] The holding member 11 holds the SiC seed crystal 2. The holding member 11 may be integrated with the crucible 10. The thermal expansion coefficient of the holding member 11 is within ±10% of the thermal expansion coefficient of the SiC seed crystal 2. The holding member 11 is made of, for example, graphite. The SiC seed crystal 2 is adhered to the holding member 11 using a carbon adhesive or the like.

[0066] 8 is an enlarged cross-sectional view of the vicinity of the holding member 11. The thickness T 11 is set to, for example, 200% or more and 800% or less of the thickness T2 of the SiC seed crystal 2. The thickness T2 of the SiC seed crystal 2 is set to, for example, 0.3 mm or more and less than 7 mm.

[0067] The holding member 11 has an expansion portion 12 inside. The expansion portion 12 has a larger expansion coefficient than the graphite constituting the holding member 11 in a high-temperature environment where SiC crystals grow. The expansion portion 12 contains a high-melting point metal or a high-melting point metal compound. The expansion portion 12 contains, for example, SiC, Ta, TaC, Nb, NbC, etc. The thickness T of the expansion portion 12 is 12 The diameter d of the expanded portion 12 is set to, for example, 50% or more and 100% or less of the thickness T2 of the SiC seed crystal 2. 12 is, for example, 30% to 70% of the diameter d2 of the SiC seed crystal 2. The expansion portion 12 is disposed at a position away from the bonding surface with the SiC seed crystal 2 by a distance of 10% to 70% of the thickness T2 of the SiC seed crystal 2. That is, the thickness T2 of the holding member 11 between the expansion portion 12 and the SiC seed crystal 2 is 13 is, for example, 10% to 70% of the thickness T2 of the SiC seed crystal 2.

[0068] The size of the holding member 11 and the expanding portion 12 affects the curvature of the grating surface S1. For example, the thickness T 11is set to 200% or more and 300% or less of the thickness T2 of the SiC seed crystal 2, and the thickness T 12 is set to 50% or more and 70% or less of the thickness T2 of the SiC seed crystal 2, and the thickness T 13 is set to 50% or more and 70% or less of the thickness T2 of the SiC seed crystal 2, and when the film formation conditions described later are satisfied, the lattice plane S1 is (ω1-ω0) / (d / 3)<-2.00×10 -6 Meet the following.

[0069] For example, the thickness T of the holding member 11 11 is more than 300% and not more than 500% of the thickness T2 of the SiC seed crystal 2, and the thickness T 12 is more than 70% and not more than 85% of the thickness T2 of the SiC seed crystal 2, and the thickness T 13 is set to 30% or more and less than 50% of the thickness T2 of the SiC seed crystal 2, and the film formation conditions described later are satisfied, the lattice plane S1 is (ω1-ω0) / (d / 3)<-3.00×10 -6 Meet the following.

[0070] For example, the thickness T of the holding member 11 11 is more than 500% and not more than 800% of the thickness T2 of the SiC seed crystal 2, and the thickness T 12 is more than 85% and 100% of the thickness T2 of the SiC seed crystal 2, and the thickness T 13 is set to 10% or more and less than 30% of the thickness T2 of the SiC seed crystal 2, and when the film formation conditions described later are satisfied, the lattice plane S1 is (ω1-ω0) / (d / 3)<-4.00×10 -6 Meet the following.

[0071] The heat insulating material 20 covers the periphery of the crucible 10. The heat insulating material 20 is, for example, graphite felt, a molded heat insulating material obtained by solidifying and molding graphite felt, or the like.

[0072] The heating member 30 surrounds the outer periphery of the crucible 10. The heating member 30 heats the SiC raw material 3. The heating member 30 is, for example, a heating coil.

[0073] When viewed from the Z direction, the shielding members 41 and 42 are disposed between the crucible 10 and the heating member 30. The radial width of the shielding members 41 and 42 is, for example, 2% to 30% of the radial width of the heating member 30. The shielding members 41 and 42 contain, for example, copper.

[0074] 9 shows a state during crystal growth of SiC single crystal 1. The position of shielding member 42 in the Z direction can be changed in accordance with the crystal growth of SiC single crystal 1. By changing the positions of shielding members 41, 42, the temperature distribution in the growth space within crucible 10 can be changed.

[0075] When growing SiC single crystal 1 using the above-described manufacturing apparatus 100, the temperature of SiC source material 3 is set to 2100°C or higher and 2400°C or lower, and the temperature of SiC seed crystal 2 is heated to 2000°C or higher and 2300°C or lower. By heating the growth space, SiC source material 3 sublimes. At this time, expansion portion 12 expands from holding member 11. As expansion portion 12 expands, SiC seed crystal 2 during crystal growth is curved convexly so that its center protrudes toward SiC source material 3. By curving the center of SiC seed crystal 2 convexly toward SiC source material 3, the curvature direction of the lattice plane of SiC single crystal 1 can be controlled.

[0076] It also controls the temperature distribution in the growth space during crystal growth of the SiC single crystal 1 and during cooling of the growth space.

[0077] First, during crystal growth of the SiC single crystal 1, the temperature distribution in the vicinity of the SiC seed crystal 2 (at the boundary between the SiC seed crystal 2 and the SiC single crystal 1) is set to satisfy the following first condition. 1st condition: 0℃ / mm<(T1-T0) / d<5.00℃ / mm

[0078] T1 is the temperature at the outer periphery of the SiC seed crystal 2, and T0 is the temperature at the center of the SiC seed crystal 2. d is the diameter of the SiC single crystal 1. The above condition can be achieved by aligning the height position of the lower end of the shielding member 41 with the height position of the upper end of the holding member 11. By controlling the temperature distribution in the vicinity of the SiC seed crystal 2, the bending direction of the SiC single crystal 1 can be controlled.

[0079] Furthermore, during the latter half of the crystal growth and cooling period of the SiC single crystal 1, the temperature distribution in the vicinity of the crystal growth surface of the SiC single crystal 1 satisfies the following second condition, and the temperature distribution at the central height position in the thickness direction of the holding member 11 satisfies the following third condition. Second condition: -5.00℃ / mm<(T1'-T0') / d<-0.01℃ / mm Third condition: -5.00℃ / mm<(T1''-T0'') / d2<-0.01℃ / mm

[0080] T1' is the temperature at the outer periphery of the SiC single crystal 1, and T0' is the temperature at the center of the SiC single crystal 1. T1'' is the temperature at the outer periphery of the holding member 11, and T0'' is the temperature at the center of the holding member 11. d2 is the diameter of the holding member 11. The latter half of the crystal growth is the time from the end of the growth time until the temperature of the SiC source material 3 exceeds 2100°C, and is in the range of 2% to 10% of the growth time. The cooling period is the time until the temperature of the SiC seed crystal 2 falls to 1000°C or below. The above conditions can be achieved by aligning the height position of the upper end of the shielding member 42 with the height position of the crystal growth surface of the growing SiC single crystal 1.

[0081] During the latter half of the crystal growth and cooling period of the SiC single crystal 1, the isothermal surface near the SiC seed crystal 2 is made convex with the center protruding toward the SiC raw material 3, and the isothermal surface near the crystal growth surface of the SiC single crystal 1 is made concave with the center moving away from the SiC raw material, thereby making the lattice plane of the SiC single crystal 1 convex toward the C-plane 1B.

[0082] The SiC single crystal 1 has a thickness T 11 By making the SiC single crystal 1 thick enough, it is possible to prevent the curvature of the lattice plane from being eliminated when the growth space cools and the expanded portion 12 returns to its original shape.

[0083] As described above, the SiC single crystal 1 according to this embodiment can be produced by providing the expansion portion 12 inside the holding member 11, controlling the temperature distribution in the growth space during crystal growth and cooling of the SiC single crystal 1, and specifying the crystal growth amount of the SiC single crystal 1. That is, by controlling the shape of the crystal growth surface of the SiC single crystal at the beginning of crystal growth and by providing the expansion portion 12 inside the holding member 11, the stress generated inside the SiC single crystal 1 can be controlled, thereby controlling the warpage (shape) of the lattice plane, and the SiC single crystal 1 according to this embodiment can be obtained.

[0084] 10 may be used instead of the holding member 11. The holding member 15 shown in FIG. 10 has a recess 16 formed therein. The recess 16 is located at a position overlapping the SiC seed crystal 2 when viewed from the Z direction. The curvature of the lattice plane of the SiC seed crystal 2 is measured using X-ray diffraction, and the curvature of the recess 16 is determined to be r≧−8.00×10 2 Here, the curvature is considered positive when it is curved in a concave shape toward the C-plane direction (so that the center is located in the -Z direction from the end).

[0085] The thickness T of the graphite member between the SiC seed crystal 2 and the recess 16 17 The thickness T of the holding member 15 in the Z direction is set to 10% or more and 70% or less of the thickness T2 of the SiC seed crystal 2. 15 is set to 200% or more and 800% or less of the thickness T2 of the SiC seed crystal 2. The radial width W of the recess 16 is set to 1% or more and 20% or less of the diameter of the holding member 15.

[0086] For example, the thickness T of the holding member 15 in the Z direction 15 is set to 200% or more and 300% or less of the thickness T2 of the SiC seed crystal 2, the radial width W of the recess 16 is set to 1% or more and 5% or less of the diameter of the holding member 15, and the thickness T 17 is set to 50% or more and 70% or less of the thickness T2 of the SiC seed crystal 2, and the above-mentioned film formation conditions are satisfied, the lattice plane S1 is (ω1-ω0) / (d / 3)<-2.00×10 -6 Meet the following.

[0087] For example, the thickness T of the holding member 15 in the Z direction 15 is more than 300% and not more than 500% of the thickness T2 of the SiC seed crystal 2, the radial width W of the recess 16 is more than 5% and not more than 10% of the diameter of the holding member 15, and the thickness T 17 is set to 30% or more and less than 50% of the thickness T2 of the SiC seed crystal 2, and the above-mentioned film formation conditions are satisfied, the lattice plane S1 is (ω1-ω0) / (d / 3)<-3.00×10 -6 Meet the following.

[0088] For example, the thickness T of the holding member 15 in the Z direction 15 is more than 500% and less than 800% of the thickness T2 of the SiC seed crystal 2, the radial width W of the recess 16 is more than 10% and 20% or less of the diameter of the holding member 15, and the thickness T 17 is set to 10% or more and less than 30% of the thickness T2 of the SiC seed crystal 2, and the above-mentioned film formation conditions are satisfied, the lattice plane S1 is (ω1-ω0) / (d / 3)<-4.00×10 -6 Meet the following.

[0089] When holding member 15 is used instead of holding member 11, the central portion of holding member 15 expands more than the portion where recess 16 is formed, and the same effect as when holding member 11 has expanded portion 12 can be obtained. That is, by controlling the shape of the crystal growth surface of the SiC single crystal in the early stage of crystal growth and controlling the stress generated inside SiC single crystal 1 by holding member 15, the warpage (shape) of the lattice plane can be controlled, and SiC single crystal 1 according to this embodiment can be obtained.

[0090] Moreover, the produced SiC single crystal 1 can be processed into a cylindrical shape and sliced ​​to produce a SiC substrate.

[0091] In the SiC single crystal 1 according to this embodiment, the lattice plane S1 has a convex shape toward the C-plane, and therefore the basal plane dislocation density of the C-plane 1B is smaller than the basal plane dislocation density of the Si-plane 1A. In other words, the SiC single crystal 1 according to this embodiment exhibits a high rate of reduction in basal plane dislocation density due to crystal growth. Therefore, the SiC single crystal 1 according to this embodiment has a low basal plane dislocation density near the C-plane, and a high-quality SiC substrate can be obtained by slicing the SiC substrate from near the C-plane.

[0092] The SiC substrate according to this embodiment is obtained by slicing the SiC single crystal 1 described above. The SiC substrate includes a SiC single crystal that satisfies the above-described conditions. The SiC substrate may be made of a SiC single crystal that satisfies the above-described conditions. Therefore, in the SiC substrate according to this embodiment, the lattice planes S1 measured along the first line L1, the second line L2, the third line L3, the fourth line L4, the fifth line L5, and the sixth line L6 are all curved in a convex shape. In the lattice planes S1 measured along the first line L1, the second line L2, the third line L3, the fourth line L4, the fifth line L5, and the sixth line L6, the center C is located closer to the C-plane than the end of the lattice plane S1 measured along each line. In other words, the lattice planes S1 measured along each line are all curved so that the center is convex toward the C-plane. The SiC substrate according to this embodiment satisfies the above-described conditions, and therefore has a small bias in the in-plane dislocation distribution. Using this SiC substrate increases the yield when fabricating SiC devices.

[0093] The thickness of the SiC substrate in the Z direction is thinner than the crystal length T in the Z direction of the SiC single crystal 1. The thickness of the SiC substrate in the Z direction is, for example, 600 μm or less, or may be 450 μm or less, 400 μm or less, 375 μm or less, 350 μm or less, or 300 μm or less.

[0094] Furthermore, a SiC epitaxial layer may be laminated on one surface of the SiC substrate according to this embodiment. The SiC epitaxial wafer includes a SiC substrate and a SiC epitaxial layer laminated on one surface of the SiC substrate. The SiC epitaxial layer may be laminated on the Si face or the C face of the SiC substrate.

[0095] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as set forth in the claims. [Example]

[0096] "Example 1" A seed crystal with a diameter of 6 inches (150 mm) was prepared. Then, using the manufacturing apparatus 100 shown in Figures 7 to 9, a SiC single crystal 1 was grown to a thickness of 32.6 mm on a SiC seed crystal 2 with a thickness of 1.2 mm.

[0097] The holding member 11 is made of graphite. 11 The thickness T of the expanded portion 12 was set to 700% of the thickness T2 of the SiC seed crystal 2. The material of the expanded portion 12 was NbC. 12 was set to 90% of the thickness T2 of the SiC seed crystal 2. The diameter d 12 was set to 60% of the diameter d2 of the SiC seed crystal 2. The thickness T of the holding member 11 between the expansion portion 12 and the SiC seed crystal 2 13 was set to 20% of the thickness T2 of the SiC seed crystal 2.

[0098] During the growth of the SiC single crystal 1, the lower end of the shielding member 41 was positioned at the same height as the upper end of the holding member 11, and the upper end of the shielding member 42 was positioned at the same height as the crystal growth surface of the growing SiC single crystal 1. As a result, the temperature distribution within the growth space during the crystal growth and cooling period satisfied the first, second, and third conditions. The moving speed of the shielding member 41 was set to 2.0 mm / h or less. If the moving speed is greater than 2.0 mm / h, the crystallinity may deteriorate due to a sudden change in temperature, resulting in a deterioration in the half-value width.

[0099] The fabricated SiC single crystal 1 was removed and subjected to X-ray diffraction measurements along the first line L1, second line L2, third line L3, fourth line L4, fifth line L5, and sixth line L6. X-ray diffraction was performed at the center, first measurement point, and second measurement point on each line. The diffraction peak angle and half-width of the maximum diffraction peak of the (0004) plane at each measurement point were then determined. Using the measurement results at the first measurement point and the center, (ω1-ω0) / (d / 3) was calculated, and using the measurement results at the second measurement point and the center, (ω2-ω0) / (d / 3) was calculated. Both of these represent the change in diffraction peak angle per unit length (deg / mm).

[0100] The X-ray diffraction results for Example 1 are summarized in the following Table 1. As shown in Fig. 4, the changes in the diffraction peak angle per unit length were all negative values, confirming that the shape of the lattice plane S1 of SiC single crystal 1 in Example 1 was a mountain shape with the center protruding toward the C-plane.

[0101] [Table 1]

[0102] Next, the defect density (EPD), basal plane dislocation density (BPD), and threading screw dislocation density (TSD) were measured on each of the Si-face 1A and C-face 1B of the produced SiC single crystal 1. The results are shown in Table 2 below. The type and number of dislocations can be determined from the shape of etch pits that appear after molten KOH etching using an optical microscope, scanning electron microscope (SEM), or the like.

[0103] [Table 2]

[0104] "Comparative Example 1" Comparative Example 1 differs from Example 1 in that a holding member made only of graphite was used. Other conditions were the same as in Example 1, and the SiC single crystal was grown. In Comparative Example 1, the SiC single crystal was grown to a length of 37.4 mm.

[0105] In Comparative Example 1, X-ray diffraction measurements were performed along the first line L1, second line L2, third line L3, fourth line L4, fifth line L5, and sixth line L6, as in Example 1. The X-ray diffraction results for Comparative Example 1 are summarized in Table 3 below. From the measurement results in Table 3, it was confirmed that the shape of the lattice plane S2 of the SiC single crystal in Comparative Example 1 was potato chip-shaped, as shown in FIG.

[0106] [Table 3]

[0107] The SiC single crystal of Comparative Example 1 was also measured for defect density (EPD), basal plane dislocation density (BPD), and threading screw dislocation density (TSD) on the Si plane and C plane, respectively. The results are shown in Table 4 below.

[0108] [Table 4]

[0109] "Comparative Example 2" Comparative Example 2 differs from Example 1 in that a holding member made only of graphite was used, and temperature control using a shielding member was not performed during crystal growth. The other conditions for growing a SiC single crystal were the same as those for Example 1. In Comparative Example 2, a SiC single crystal was grown to a length of 38.3 mm.

[0110] In Comparative Example 2, X-ray diffraction measurements were performed along the first line L1, second line L2, third line L3, fourth line L4, fifth line L5, and sixth line L6, as in Example 1. The X-ray diffraction results for Comparative Example 2 are summarized in Table 5 below. From the measurement results in Table 5, it was confirmed that the shape of the lattice plane S3 of the SiC single crystal in Comparative Example 2 was bowl-shaped, with the center protruding in the direction away from the C-plane, as shown in FIG.

[0111] [Table 5]

[0112] The defect density (EPD), basal plane dislocation density (BPD), and threading screw dislocation density (TSD) were also measured on the Si-face and C-face of the SiC single crystal of Comparative Example 2. The results are shown in Table 6 below.

[0113] [Table 6]

[0114] The SiC single crystal of Example 1 had a lower basal plane dislocation density in the C-plane than those of Comparative Examples 1 and 2. Furthermore, the SiC single crystal of Example 1 exhibited a greater rate of reduction in basal plane dislocation density during crystal growth than those of Comparative Examples 1 and 2.

[0115] In Example 1, Comparative Example 1, and Comparative Example 2, SiC single crystals were produced using a SiC seed crystal with a diameter of 6 inches (150 mm). A similar study was conducted using a SiC seed crystal with a diameter of 8 inches (200 mm). When the diameter was 200 mm, the same tendency as when the diameter was 150 mm was confirmed. [Explanation of symbols]

[0116] 1. SiC single crystal 1A Si surface 1B C side 2 SiC seed crystal 3 SiC raw material 10 Crucible 11, 15 Holding member 12 Expansion section 16 Recess 20. Insulation 30 Heating element 41, 42 Shielding member 100 Manufacturing equipment A atom L1 1st straight line L2 2nd straight line L3 3rd straight line L4 4th straight line L5 5th straight line L6 6th straight line p11, p21, p31, p41, p51, p61 1st measurement point p12, p22, p32, p42, p52, p62 2nd measurement point S1, S2, S3 lattice planes

Claims

1. the grating planes measured along the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line are all curved in a convex shape; a center of the lattice plane measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line is located on a C-plane side of an end of the lattice plane measured along each of the lines; the first straight line is a straight line passing through the center when viewed in a plan view from the thickness direction, the second straight line is a straight line that passes through the center and is inclined at 30° with respect to the first straight line with respect to the center; the third straight line is a straight line that passes through the center and is inclined at 60° with respect to the first straight line with respect to the center; the fourth straight line passes through the center and is inclined at 90° with respect to the first straight line with respect to the center; the fifth straight line is a straight line that passes through the center and is inclined at 120° with respect to the first straight line with respect to the center; The SiC single crystal, wherein the sixth line passes through the center and is inclined at 150° with respect to the first line with respect to the center.

2. The main surface has an offset angle with respect to the (0001) plane, 2. The SiC single crystal according to claim 1, wherein the first straight line is a straight line extending in the <11-20> direction.

3. The diameter when viewed from above in the thickness direction is d, and the maximum diffraction peak angle of the (0004) plane at the center is ω ０ , the maximum diffraction peak angle of the (0004) plane at the measurement point d / 3 away from the center is defined as ω １ When I said, In the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, (ω １ -ω ０ ) / (d / 3) < -2.00 × 10 －６ The SiC single crystal according to claim 1 , which satisfies the above.

4. In the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, (ω １ -ω ０ ) / (d / 3) < -3.00 × 10 －６ The SiC single crystal according to claim 3 , which satisfies the above.

5. In the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, (ω １ -ω ０ ) / (d / 3) < -4.00 × 10 －６ The SiC single crystal according to claim 4, which satisfies the above.

6. When the diameter when viewed in a plan view from the thickness direction is d, In the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, the half-width of the maximum diffraction peak of the (0004) plane at a measurement point d / 3 away from the center is 5.20 × 10 －２ The SiC single crystal of claim 1 , wherein the SiC single crystal has a crystallinity of less than 1000 nm.

7. In the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, the half-width of the maximum diffraction peak of the (0004) plane at a measurement point d / 3 away from the center is 4.80 × 10 －２ The SiC single crystal of claim 6, wherein the SiC single crystal has a crystallinity of less than 1000 nm.

8. In the X-ray diffraction results measured along each of the first line, the second line, the third line, the fourth line, the fifth line, and the sixth line, the half-width of the maximum diffraction peak of the (0004) plane at a measurement point d / 3 away from the center is 4.40 × 10 －２ The SiC single crystal of claim 6, wherein the SiC single crystal has a crystallinity of less than 1000 nm.

9. The basal plane dislocation density on the Si surface is called BPD. ０ , the basal plane dislocation density on the C-plane is BPD １ , and when (BPD ０ -BPD １ ) / BPD ０ The SiC single crystal according to claim 1, wherein the SiC single crystal satisfies >64%.

10. The threading screw dislocation density on the Si surface is TSD. ０ , the threading screw dislocation density on the C-plane is TSD １ , and when (TSD ０ -TSD １ ) / TSD ０ The SiC single crystal according to claim 1, wherein the SiC single crystal satisfies >48.2%.

11. The basal plane dislocation density on the Si surface is called BPD. ０ , the basal plane dislocation density on the C-plane is BPD １ , the threading screw dislocation density on the Si surface is TSD ０ , the threading screw dislocation density on the C-plane is TSD １ , and the crystal length in the thickness direction is T, (BPD ０ -BPD １ ) / (BPD ０ × T) > 1% / mm, (TSD ０ -TSD １ ) / (TSD ０ 2. The SiC single crystal according to claim 1, wherein the SiC single crystal satisfies the following:

12. (BPD ０ -BPD １ ) / (BPD ０ × T) > 2% / mm, (TSD ０ -TSD １ ) / (TSD ０ 12. The SiC single crystal according to claim 11, wherein the SiC single crystal satisfies the following:

13. (BPD ０ -BPD １ ) / (BPD ０ × T) > 3% / mm, (TSD ０ -TSD １ ) / (TSD ０ 13. The SiC single crystal according to claim 12, wherein the SiC single crystal satisfies the following:

14. 2. The SiC single crystal according to claim 1, having a diameter of 145 mm or more when viewed in a plan view in the thickness direction.

15. 2. The SiC single crystal according to claim 1, having a diameter of 195 mm or more when viewed in a plan view in the thickness direction.

16. 2. The SiC single crystal according to claim 1, having a diameter of 295 mm or more when viewed in a plan view in the thickness direction.

17. The basal plane dislocation density on the C-plane is 500 / cm ２ 2. The SiC single crystal according to claim 1, wherein:

18. The threading screw dislocation density on the C-plane is 300 / cm ２ 2. The SiC single crystal according to claim 1, wherein:

19. The defect density on the C-plane is 4000 / cm ２ 2. The SiC single crystal according to claim 1, wherein:

20. A SiC substrate comprising the SiC single crystal of claim 1.

21. A SiC epitaxial wafer comprising: the SiC substrate according to claim 20; and a SiC epitaxial layer stacked on one surface of the SiC substrate.

Images