Susceptor and SiC epitaxial growth apparatus

Abstract

The present invention provides a susceptor and a SiC epitaxial growth apparatus that can suppress interference with wafer removal. [Solution] The susceptor of the embodiment comprises a support base and an annular wafer guide. The support base has a support surface for supporting the wafer. The wafer guide surrounds the wafer supported on the support surface, with a central axis extending in the direction normal to the support surface. The inner circumferential surface of the wafer guide, viewed from the axial direction of the central axis, is provided with an arc-shaped arc portion and a rotation stopper portion. The arc portion extends along a virtual circle centered on the central axis. The rotation stopper portion is located radially inward with respect to the virtual circle. The rotation stopper portion has a tip portion and a side portion. The tip portion is located at the radially inward end of the rotation stopper portion. The side portion is located on at least one side of the tip portion in the circumferential direction with respect to the central axis. The side portion extends radially outward from the tip portion. The side portion connects to the arc portion.

Description

Technical Field

[0001] Embodiments of the present invention relate to a susceptor and a SiC epitaxial growth apparatus.

Background Art

[0002] In a susceptor in a SiC epitaxial growth apparatus, a wafer guide is disposed around a wafer supported on a support surface. The wafer guide is provided with a flat portion facing the flat portion of the wafer in order to suppress the rotation of the wafer. When the wafer guide thermally contracts, it may bite into the wafer at the flat portion and the inner peripheral surface on the opposite side, making it difficult to transport the wafer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a susceptor and a SiC epitaxial growth apparatus capable of suppressing the prevention of wafer unloading.

Means for Solving the Problems

[0005] The susceptor of the embodiment comprises a support base and an annular wafer guide. The support base has a support surface for supporting the wafer. The wafer guide surrounds the wafer supported on the support surface, with a central axis extending in the direction normal to the support surface. The inner circumferential surface of the wafer guide, viewed from the axial direction of the central axis, is provided with an arc-shaped arc portion and a rotation stopper portion. The arc portion extends along a virtual circle centered on the central axis. The rotation stopper portion is located radially inward with respect to the virtual circle. The rotation stopper portion has a tip portion and a side portion. The tip portion is located at the radially inward end of the rotation stopper portion. The side portion is located on at least one side of the tip portion in the circumferential direction with respect to the central axis. The side portion extends radially outward from the tip portion. The side portion connects to the arc portion. [Brief explanation of the drawing]

[0006] [Figure 1] A cross-sectional view showing a SiC epitaxial growth apparatus according to one embodiment. [Figure 2] A plan view showing a wafer guide in one embodiment. [Figure 3] A plan view showing the wafer guide of modified example 1. [Figure 4] A plan view showing the wafer guide of modified example 2. [Figure 5] A plan view showing the wafer guide of modified example 3. [Figure 6] A plan view showing the wafer guide of modified example 4. [Figure 7] A plan view showing a wafer guide in a comparative configuration. [Modes for carrying out the invention]

[0007] The susceptor and SiC epitaxial growth apparatus of the embodiment will be described below with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. Duplication of these components may be omitted.

[0008] The configuration of the SiC epitaxial growth apparatus will be described below. Figure 1 is a cross-sectional view of a SiC epitaxial growth apparatus 1 having a susceptor 10 according to an embodiment.

[0009] In the following explanation, the side into which the supplied raw material gas flows will be referred to as the upper side, and the side out which it flows will be referred to as the lower side. Each figure shows the central axis J of the susceptor 10. In the following explanation, the axial direction of the central axis J may be simply referred to as the "axial direction." The radial direction centered on the central axis J may be simply referred to as the "radial direction." Furthermore, the circumferential direction around the central axis J may be simply referred to as the "circumferential direction."

[0010] As shown in Figure 1, the SiC epitaxial growth apparatus 1 grows an epitaxial film, which will be the active region, on a wafer W made of silicon carbide (SiC) by chemical vapor deposition (thermal CVD) or the like. The SiC epitaxial growth apparatus 1 comprises a chamber 2, a reactor member 3, an upper heater 4, a lower heater 5, a rotating cylinder 6, a partition cylinder 7, a susceptor 10, and a lifting / lowering section 15.

[0011] Chamber 2 is made of a metal material such as stainless steel (SUS). Chamber 2 houses the reactor member 3, upper heater 4, lower heater 5, rotating cylinder 6, partition cylinder 7, and susceptor 10. Chamber 2 has an inlet 2A, an exhaust port 2B, and an insertion port 2C. The inlet 2A is provided on the top plate of Chamber 2. The exhaust port 2B and the insertion port 2C are provided on the bottom 2D of Chamber 2.

[0012] The inlet 2A is formed as an opening at the upper end of the chamber 2. The inlet 2A is the point where the working gas, including the raw material gas G supplied from above along the central axis J, is introduced into the chamber 2. The exhaust port 2B is the point where the working gas, including the raw material gas G used in the SiC epitaxial growth process, is exhausted.

[0013] The raw material gas G reacts on the wafer W to form an epitaxial film. The raw material gas G is, for example, a Si-based gas and a C-based gas. Examples of Si-based gases include silane (SiH4), dichlorosilane (SiH2Cl2), trichlorosilane (SiHCl3), and tetrachlorosilane (SiCl4). An example of a C-based gas is propane (C3H8). In one embodiment, the raw material gas G is SiH4 + C3H8 (flow rate: tens to hundreds of sccm).

[0014] Other gases used in addition to the raw material gas G include impurity gases, carrier gases, and other gases. Examples of impurity gases include N2 (N-type impurity) and TMA (P-type impurity) (flow rate: several to several hundred sccm). Examples of carrier gases include H2 (during growth) and Ar (during transport) (flow rate: 100 to 200 slm). Examples of other gases include HCl (particle suppression during growth, high-speed growth) (flow rate: tens of sccm to several hundred slm).

[0015] The reactor member 3 constitutes the furnace. The reactor member 3 is formed of graphite, for example. The reactor member 3 may have a SiC coating or a TaC coating on its inner surface to prevent dust generation. The reactor member 3 has a first cylindrical portion 3A, a tapered portion 3B, and a second cylindrical portion 3C.

[0016] The first cylindrical portion 3A is located on the upper side of the reactor member 3. The first cylindrical portion 3A opens below the inlet 2A of the chamber 2. The gas, including the raw material gas G, introduced from the inlet 2A is introduced into the internal space of the reactor member 3. The internal space of the reactor member 3 is the film deposition space K.

[0017] The tapered portion 3B extends in a direction toward the outer side in the radial direction as it goes downward from the lower end of the first cylindrical portion 3A. The second cylindrical portion 3C extends downward from the lower end of the tapered portion 3B. The position of the second cylindrical portion 3C in the radial direction is outside the exhaust port 2B of the chamber 2 in the radial direction. The tapered portion 3B is arranged in a range including the axial position of the first surface Wa facing the upper side of the wafer W in the vertical direction. Therefore, the gas containing the source gas G introduced into the film formation space K from the introduction port 2A flows radially outward along the first surface Wa after reaching the wafer W. The gas containing the source gas G that has flowed radially outside the wafer W is guided by the tapered portion 3B and the second cylindrical portion 3C and discharged from the exhaust port 2B of the chamber 2.

[0018] The upper heater 4 surrounds the outer periphery of the first cylindrical portion 3A in the reactor member 3 in the circumferential direction. The upper heater 4 extends axially along the first cylindrical portion 3A. The lower heater 5 is disposed below the susceptor 10 and separated from the susceptor 10. The lower heater 5 is, for example, annular and extends in the circumferential direction. By heating the upper heater 4 and the lower heater 5, the wafer W is heated, for example, in the range of 1500 to 1650 °C. Known ones can be used for the upper heater 4 and the lower heater 5.

[0019] The rotating cylinder 6 is rotatable in the circumferential direction. The rotating cylinder 6 has a first rotating cylinder 6A and a second rotating cylinder 6B. The first rotating cylinder 6A is provided above the second rotating cylinder 6B. The first rotating cylinder 6A is disposed above the bottom 2D in the chamber 2. The lower heater 5 is disposed inside the first rotating cylinder 6A. The diameter of the first rotating cylinder 6A is larger than the diameter of the second rotating cylinder 6B. The second rotating cylinder 6B extends downward from the first rotating cylinder 6A. The second rotating cylinder 6B is inserted into the insertion port 2C.

[0020] The partition cylinder 7 is fixed to the bottom 2D in the chamber 2. The partition cylinder 7 extends upward along the axial direction. The partition cylinder 7 is disposed radially inside the second cylindrical portion 3C and separated radially outside the first rotating cylinder 6A.

[0021] The lifting unit 15 is axially movable between a lowered position and an raised position. In the lowered position, the lifting unit 15 is located below the susceptor 10. By moving from the lowered position to the raised position, the lifting unit 15 lifts the wafer W that is mounted on the susceptor 10 through the through-hole 11B of the susceptor 10.

[0022] The susceptor 10 comprises a support base 11 and a wafer guide 20. The susceptor 10 supports the wafer W on the support surface 11f of the support base 11. The support surface 11f is perpendicular to the central axis J. That is, the normal direction of the support surface 11f extends parallel to the central axis J.

[0023] The support base 11 is disc-shaped with respect to the central axis J. The support base 11 is fixed to the rotating cylinder 6. The support base 11 rotates together with the rotating cylinder 6 about the central axis J. The support base 11 has a support surface 11f and a through hole 11B. The support surface 11f supports the wafer W from below, radially outside the through hole 11B. The through hole 11B penetrates the support base 11 axially with respect to the central axis J.

[0024] The wafer guide 20 is joined and fixed to the support surface 11f of the support base 11. The wafer guide 20 rotates together with the support base 11 around the central axis J.

[0025] Figure 2 is a plan view of the wafer guide 20 of this embodiment. In Figure 2, the wafer W, which is placed radially inside the wafer guide 20, is shown by a dashed line.

[0026] The wafer W has a roughly circular shape, and a linear flat portion Wc is provided in part to indicate the crystal orientation of the wafer W. That is, the outer surface of the wafer W is provided with an arc-shaped outer portion Wb that extends in an arc when viewed from the axial direction, and a linear flat portion Wc that extends in a linear direction when viewed from the axial direction. The flat portion Wc is connected to one end and the other end of the arc-shaped outer portion Wb in the circumferential direction, respectively. Corner portions Wp are provided at the boundary between the arc-shaped outer portion Wb and the flat portion Wc. There are two corner portions Wp on the outer circumference of the wafer W.

[0027] The wafer guide 20 is an annular shape that surrounds the wafer W, which is supported on the support surface 11f, with its central axis J as the center.

[0028] The wafer guide 20 has an inner circumferential surface 20f that faces the outer circumferential surface of the wafer W in the radial direction. The inner circumferential surface 20f is provided with an arc portion 21 and a rotation stopper portion 22.

[0029] The arc portion 21 extends in an arc shape along the circumferential direction with a constant radius centered on the central axis J. The radius of the arc portion 21 is slightly larger than the radius of the wafer W. The arc portion 21 surrounds the outer circumferential surface of the wafer W from the radial outside. As a result, the arc portion 21 guides the outer circumferential surface of the wafer W during the film deposition process and prevents the wafer W from separating from the support surface 11f.

[0030] As shown in Figure 2, a virtual circle VC is assumed to be centered on the central axis J when viewed from the axial direction. The radius of the virtual circle VC is equal to the radius of the arc portion 21. Therefore, the virtual circle VC extends along the arc portion 21.

[0031] The rotation-stopping portion 22 is located radially inward with respect to the virtual circle VC. In this embodiment, the rotation-stopping portion 22 protrudes radially inward with respect to the arc portion 21. In this embodiment, the rotation-stopping portion 22 is substantially rectangular when viewed from the axial direction. The rotation-stopping portion 22 has a tip surface (tip portion) 22a and a pair of side portions 22b.

[0032] The tip surface 22a is located at the radially inner end of the rotation-stopping portion 22. In this embodiment, the tip surface 22a is a flat surface facing radially inward.

[0033] The side portions 22b are located on one and the other side of the tip surface 22a in the circumferential direction. Each of the pair of side portions 22b connects to the tip surface 22a. The side portions 22b extend radially outward from the tip surface 22a.

[0034] The side portion 22b has a chamfered portion 22d and a side surface 22f. The side surface 22f is a flat surface perpendicular to the tip surface 22a. Of the pair of side surfaces 22f, one faces one side in the circumferential direction and the other faces the other side in the circumferential direction. The chamfered portion 22d connects the tip surface 22a and the side surface 22f. The chamfered portion 22d is inclined with respect to both the tip surface 22a and the side surface 22f.

[0035] Because the support surface 11f is formed smoothly, the wafer W may slide and rotate on the support surface 11f. Furthermore, during the film deposition process, reaction products may accumulate not only on the top surface of the wafer W but also in areas of the support surface 11f where the wafer W is not mounted. Therefore, when the wafer W slides and rotates and moves on the support surface 11f, the reaction products accumulated on the support surface 11f may adhere to the back surface of the wafer W. If the movement of the wafer W on the support surface 11f is large, the amount of reaction products adhering to the back surface of the wafer W will also increase, leading to the problem of the wafer W's surface tilting in subsequent processes.

[0036] The wafer guide 20 in this embodiment has a rotation-stopping portion 22 on its inner circumferential surface 20f. Therefore, when mounting the wafer W on the support surface 11f, the flat portion Wc of the wafer W is positioned opposite the tip surface 22a of the rotation-stopping portion 22, thereby limiting the rotation of the wafer W even if it slips on the support surface 11f.

[0037] As shown in Figure 2, the point furthest inward in the rotation-stopping portion 22 is defined as the tip point P. The tip point P is located on the tip surface 22a. Furthermore, the straight line connecting the tip point P and the central axis J, viewed from the axial direction, is defined as the first reference line L1. In addition, the straight line perpendicular to the first reference line along the tip point P, viewed from the axial direction, is defined as the second reference line L2. According to the wafer guide 20 of this embodiment, the rotation-stopping portion 22 is located on one and the other side in the circumferential direction of the tip surface 22a and has side portions 22b extending radially outward from the tip surface 22a. For this reason, the inner circumferential surface 20f of the wafer guide 20 is provided with a retractable recess 23 located radially outward with respect to the second reference line L2.

[0038] Figure 7 is a plan view of the wafer guide 1020 in a comparative configuration. The effects and advantages of this embodiment will be explained by comparing it with the comparative configuration.

[0039] As shown in Figure 7, the inner circumferential surface 1020f of the comparative wafer guide 1020 is provided with an arc portion 1021 and a rotation stopper portion 1022. The arc portion 1021 extends circumferentially along a virtual circle VC. The rotation stopper portion 1022 is located radially inward with respect to the virtual circle VC. The rotation stopper portion 1022 has a tip surface 1022a that faces radially inward. The tip surface 1022a is a flat surface that extends in a straight line. The circumferential ends on both sides of the tip surface 1022a connect to the arc portion 1021.

[0040] In the comparative wafer guide 1020, when the wafer W rotates on the support surface 11f, the wafer W's corner Wp comes into contact with the tip surface 1022a, thereby restricting the rotation of the wafer W. In this case, the wafer W also comes into contact with the wafer guide 1020 at the contact point Wq opposite the corner Wp, with the center of the wafer W in between. Furthermore, in the film deposition process, the temperature inside the chamber 2 is increased to perform film deposition. Due to heat dissipation after the film deposition process, the wafer guide 1020 may shrink due to heat, and the wafer W may become trapped in the wafer guide 1020. In this case, it becomes difficult for the wafer W to detach from the wafer guide 1020, making it difficult to remove the wafer W from the susceptor 10.

[0041] As shown in Figure 2, according to this embodiment, the inner circumferential surface 20f of the wafer guide 20, when viewed from the axial direction, is provided with an arc portion 21 and a rotation stopper portion 22. The arc portion 21 is arc-shaped and extends along a virtual circle VC centered on the central axis J. At least a portion of the rotation stopper portion 22 is located radially inward with respect to the virtual circle VC. The rotation stopper portion 22 has a tip surface 22a and a side portion 22b. The tip surface 22a is located at the radially inward end of the rotation stopper portion 22. The side portion 22b is located at least one side in the circumferential direction relative to the tip surface 22a. The side portion 22b extends radially outward from the tip surface 22a. The side portion 22b connects to the arc portion 21. With this configuration, a retractable recess 23 can be formed on at least one side in the circumferential direction of the rotation stopper portion 22, recessing radially outward relative to the rotation stopper portion 22. Therefore, when the wafer W rotates inside the wafer guide 20, the flat portion Wc can be brought into contact with the rotation stopper portion 22, and the corner portion Wp can be positioned inside the retractable recess 23. As a result, even if the wafer guide 20 shrinks due to heat, it is possible to prevent the wafer W from getting caught in the inner circumferential surface 20f of the wafer guide 20. This makes it possible to smoothly remove the wafer W from the susceptor 10 after the film deposition process. In other words, according to this embodiment, it is possible to provide a susceptor 10 that can prevent interference with the removal of the wafer W.

[0042] As shown in Figure 2, the rotation stopper 22 and the virtual circle VC intersect at two intersection points C on one and the other side in the circumferential direction. Here, the distance between the two intersection points C is defined as the width dimension A2 of the rotation stopper 22. It is preferable that the width dimension A2 of the rotation stopper 22 is shorter than the length dimension B1 of the flat portion Wc of the wafer W as viewed from the axial direction. In this case, when the wafer W rotates, it becomes easier to position the corner portion Wp of the wafer W in the retractable recess 23, and it becomes easier to further suppress the wafer guide 20 from biting the wafer W.

[0043] In this embodiment, the width dimension A3 of the retractable recess 23 along the second reference line L2 is preferably 50% or more of the width dimension A2 of the rotation stopper 22. In this case, by ensuring that the retractable recess 23 is sufficiently large relative to the tip surface 22a of the rotation stopper 22, it becomes easier to position the corner Wp of the wafer W in the retractable recess 23. This makes it possible to provide a wafer guide 20 that can suppress wafer jamming even if the dimensions of each part of the wafer W are slightly changed within the range that fits inside the wafer guide 20.

[0044] In this embodiment, the side portions 22b are provided on one and the other sides in the circumferential direction relative to the tip surface 22a. According to this embodiment, retractable recesses 23 can be formed on both sides in the circumferential direction of the rotation stopper portion 22. According to this embodiment, no matter which direction the wafer W rotates on the support surface 11f, the corner portion Wp can be positioned in one of the retractable recesses 23, preventing the wafer W from getting caught in the inner circumferential surface 20f. In particular, the two retractable recesses 23 of this embodiment are arranged mirror-symmetrically with respect to the first reference line L1. Therefore, no matter which direction the wafer W rotates, the corner portion Wp can be retracted into the retractable recess 23 in the same way.

[0045] According to this embodiment, the side portion 22b has a chamfered portion 22d provided at the portion connected to the tip surface 22a. That is, the rotation-stopping portion 22 of this embodiment has a chamfered portion 22d at its corner. Therefore, the rotation of the wafer W can be restricted by bringing it into contact with the chamfered portion 22d of the rotation-stopping portion 22. In other words, according to this embodiment, the flat portion Wc of the wafer W does not come into contact with the corner portion of the rotation-stopping portion 22, and the application of a large localized force to the wafer W can be suppressed. Note that a curved surface may be provided at the corner portion of the rotation-stopping portion 22 instead of the chamfered portion 22d.

[0046] (Variation 1) Figure 3 is a plan view of a modified wafer guide 120 of Modification 1, which can be used in the susceptor 10 of the above-described embodiment. The wafer guide 120 of this modification differs from the above-described embodiment mainly in the shape of the side portion 122b.

[0047] Similar to the embodiments described above, the inner circumferential surface 120f of the wafer guide 120 is provided with an arc portion 121 extending along a virtual circle VC and a rotation-stopping portion 122 located radially inward with respect to the virtual circle. The rotation-stopping portion 122 has a tip surface (tip portion) 122a and a pair of side portions 122b. The tip surface 122a is a flat surface located at the radially inward end of the rotation-stopping portion 122 and facing radially inward.

[0048] In this modified example, the side portions 122b are located on one and the other circumferential side of the tip surface 122a. Each of the pair of side portions 122b connects to the tip surface 122a. The side portions 122b extend radially outward from the tip surface 122a.

[0049] The side portion 122b has a first side portion 122f, a second side portion 122h, and a third side portion 122g. The first side portion 122f and the second side portion 122h face each other. The first side portion 122f and the second side portion 122h extend along the radial direction. The first side portion 122f connects to the tip surface 122a. The second side portion 122h connects to the arc portion 121. The third side portion 122g faces radially inward. The third side portion 122g connects to the radially outer end of the first side portion 122f. The third side portion 122g connects to the radially outer end of the second side portion 122h.

[0050] In this modified example, the side portion 122b extends radially outward from the tip surface 122a on the first side surface 122f. Furthermore, the side portion 122b connects to the arc portion 121 on the second side surface 122h. Therefore, in this modified example, a retractable recess 123 capable of accommodating the corner portion Wp of the wafer W can be formed on the inner circumferential surface 120f of the wafer guide 120, similar to the embodiment described above. This prevents the wafer W from becoming jammed in the inner circumferential surface 120f of the wafer guide 120. The retractable recess 123 in this modified example extends radially outward with respect to the virtual circle VC. Even when forming such a retractable recess 123, the same effects as in the embodiment described above can be obtained.

[0051] (Modification 2) Figure 4 is a plan view of a modified wafer guide 220 of Modification 1, which can be used in the susceptor 10 of the above-described embodiment. The wafer guide 220 of this modified embodiment differs from the above-described embodiment mainly in that the rotation stopper portion 222 has only one side portion 222b, and that the side portion 222b has a curved surface 222d.

[0052] The inner circumferential surface 220f of the wafer guide 220 is provided with an arc portion 221 extending along a virtual circle VC and a rotation-stopping portion 222 located radially inward from the virtual circle. The rotation-stopping portion 222 has a tip surface (tip portion) 222a and a side portion 222b. In this modified example, the side portion 222b is provided only on one side in the circumferential direction relative to the tip surface 222a. The other end of the tip surface 222a in the circumferential direction is connected to the arc portion 221.

[0053] In this modified example, the side portion 222b is provided only on one side in the circumferential direction relative to the rotation stopper portion 222. In a typical film deposition process, the rotation direction of the rotating cylinder 6 (see Figure 1) is unidirectional. Furthermore, the wafer W being jammed by the wafer guide occurs during heat dissipation after the film deposition process. The wafer W on the support surface 11f slides in the rotation direction of the rotating cylinder 6 due to the inertial force accompanying the stopping of the rotating cylinder 6. Therefore, the rotational displacement of the wafer W during heat dissipation is basically unidirectional. According to this modified example, by arranging the side portion 222b in accordance with the rotation direction of the rotating cylinder 6, the jamming of the wafer W by the wafer guide 220 can be suppressed. The side portion 222b is formed, for example, by a cutting process. According to this modified example, by reducing the number of side portions 222b, the time required for the cutting process during the manufacturing of the wafer guide 220 can be shortened, and the manufacturing cost of the susceptor 10 can be reduced.

[0054] In this modified example, the side portion 222b has a curved surface 222d. The curved surface 222d is a convex arc surface. The curved surface 222d connects to the tip surface 222a at its radially inner end. The curved surface 222d also connects to the arc portion 221 at its radially outer end.

[0055] In this modified example, the curved surface 222d smoothly connects to the tip surface 222a, thereby suppressing the formation of corners on the rotation-stopping portion 222. According to this modified example, no corners are formed on the rotation-stopping portion 222, and when the wafer W rotates, the wafer W can be brought into contact with the curved surface 222d, thereby limiting the rotation of the wafer W. Therefore, it is possible to suppress the application of a large localized force to the flat portion Wc of the wafer W. Note that a chamfered portion may be provided at the corner of the rotation-stopping portion 222 instead of the curved surface 222d.

[0056] (Variation 3) Figure 5 is a plan view of a modified wafer guide 320 of modification 3, which can be used in the susceptor 10 of the above-described embodiment. The main difference between this modified wafer guide 320 and the above-described embodiment is that a recess 322e is provided in the rotation stopper portion 322.

[0057] Similar to the embodiment described above, the inner circumferential surface 320f of the wafer guide 320 in this modified example is provided with an arc portion 21 extending along a virtual circle VC and a rotation-stopping portion 322 located radially inward with respect to the virtual circle.

[0058] Similar to the embodiments described above, the rotation-stopping portion 322 of this modified example has a tip surface (tip portion) 322a facing radially inward and a pair of side portions 322b. The tip surface 322a of this modified example is provided with a recess 322e that is recessed radially outward. The recess 322e is located at the circumferential center of the tip surface 322a. The radially outer end of the recess 322e of this modified example extends in an arc shape along a virtual circle VC. However, the position and shape of the radially outer end of the recess 322e are not limited to this modified example.

[0059] In the film deposition process, reaction products accumulate not only on the upper surface of the wafer W but also on the upper surface of the wafer guide 320. In particular, since the rotation stopper 322 is located radially inward and positioned close to the wafer W, reaction products tend to accumulate on the upper surface of the rotation stopper 322. The deposits on the upper surface of the rotation stopper 322 may adhere to the wafer W during loading or transport. According to this modified example, the rotation stopper 322 is provided with a recess 322e that is recessed radially outward. This reduces the surface area of ​​the upper surface of the rotation stopper 322, thereby suppressing the accumulation of reaction products on the wafer guide 320. This also prevents the reaction products on the upper surface of the rotation stopper 322 from adhering to the wafer W during loading or unloading.

[0060] (Modification 4) Figure 6 is a plan view of a modified wafer guide 420 of Modification 4, which can be used in the susceptor 10 of the above-described embodiment. The wafer guide 420 of this modified embodiment differs from the above-described embodiment mainly in the shape of the rotation stopper portion 422.

[0061] Similar to the embodiment described above, the inner circumferential surface 420f of the wafer guide 420 in this modified example is provided with an arc portion 21 extending along a virtual circle VC and a rotation-stopping portion 422 located radially inward with respect to the virtual circle.

[0062] In this modified example, the rotation-stopping portion 422 is semicircular when viewed from the axial direction. The rotation-stopping portion 422 has a tip portion 422a and a pair of side portions 422b. The tip portion 422a is located at the radially inner end of the rotation-stopping portion 422. The side portions 422b are located on both sides of the tip portion in the circumferential direction. The side portions 422b extend radially outward from the tip portion 422a. The side portions 422b also connect to the arc portion 21. In this modified example, the entire side portion 422b is a curved surface. According to this modified example, the rotation of the wafer W, which slides and rotates on the support surface 11f, can be restricted by bringing it into contact with the curved surface. This makes it possible to suppress the application of a large localized force to the flat portion Wc of the wafer W.

[0063] According to at least one embodiment described above, by having wafer guides 20, 120, 220, 320, and 420, which are provided with rotation-stopping portions 22, 122, 222, 322, and 422 having side portions 22b, 122b, 222b, 322b, and 422b on their inner circumferential surfaces 20f, 120f, 220f, 320f, and 420f, it is possible to suppress the wafer W from sliding and rotating while also suppressing obstruction of the wafer W's removal.

[0064] This embodiment includes the following appended aspects. (Note 1) A support base having a support surface for supporting a wafer, The wafer supported on the support surface is surrounded by an annular wafer guide centered on a central axis extending in the direction normal to the support surface, Viewed from the axial direction of the central axis, the inner circumferential surface of the wafer guide is as follows: An arc-shaped arc portion extending along a virtual circle centered on the aforementioned central axis, A rotation stopper is provided, at least a portion of which is located radially inward of the virtual circle. The aforementioned rotation stopper is The tip portion located at the radially inner end of the rotation-stopping portion, It has a side portion located on at least one side of the tip portion in the circumferential direction with respect to the central axis, extending radially outward from the tip portion and connecting to the arc portion, Suscepta. (Note 2) The side portions are provided on one side and the other side in the circumferential direction relative to the tip portion, The susceptor described in Appendix 1. (Note 3) The aforementioned side portion is provided on one side in the circumferential direction relative to the aforementioned tip portion. The other end of the tip portion in the circumferential direction is connected to the arc portion. The susceptor described in Appendix 1. (Note 4) The rotation-stopping portion is provided with a recess that is recessed outward in the radial direction. A susceptor as described in any one of the appendices 1 to 3. (Note 5) The side portion has a curved surface or a chamfered portion that is provided at the part that connects to the tip portion. A susceptor as described in any one of the appendices 1 to 4. (Note 6) A linearly extending flat portion is provided on the outer circumferential surface of the wafer. The distance between the two intersection points on one and the other side of the circumferential direction between the rotation-stopping portion and the virtual circle is shorter than the length dimension of the flat portion as viewed from the axial direction. A susceptor as described in any one of the appendices 1 to 5. (Note 7) A susceptor comprising the one described in any one of claims 1 to 6, SiC epitaxial growth apparatus.

[0065] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0066] 1…SiC epitaxial growth apparatus, 10…Susceptor, 11…Support base, 11f…Support surface, 20, 120, 220, 320, 420, 1020…Wafer guide, 20f, 120f, 220f, 320f, 420f, 1020f…Inner circumferential surface, 21, 121, 221, 1021…Arch section, 22, 122, 222, 322, 422 ,1022…Rotation stopper part, 22a,122a,222a,322a…Tip surface (tip part), 22b,122b,222b,322b,422b…Side part, 22d…Chamfered part, 222d…Curved surface, 322e…Recess, 422a…Tip part, B1…Length dimension, C…Intersection, J…Central axis, VC…Virtual circle, W…Wafer, Wc…Flat part

Claims

1. A support base having a support surface for supporting a wafer, The wafer supported on the support surface is surrounded by an annular wafer guide centered on a central axis extending in the direction normal to the support surface, Viewed from the axial direction of the central axis, the inner circumferential surface of the wafer guide is as follows: An arc-shaped arc portion extending along a virtual circle centered on the aforementioned central axis, A rotation stopper is provided, at least a portion of which is located radially inward of the virtual circle. The aforementioned rotation stopper is The tip portion located at the radially inner end of the rotation-stopping portion, It has a side portion located on at least one side of the tip portion in the circumferential direction with respect to the central axis, extending radially outward from the tip portion and connecting to the arc portion, Suscepta.

2. The side portions are provided on one side and the other side in the circumferential direction relative to the tip portion, The susceptor according to claim 1.

3. The aforementioned side portion is provided on one side in the circumferential direction relative to the aforementioned tip portion. The other end of the tip portion in the circumferential direction is connected to the arc portion. The susceptor according to claim 1.

4. The rotation-stopping portion is provided with a recess that is recessed outward in the radial direction. The susceptor according to claim 1.

5. The side portion has a curved surface or a chamfered portion that is provided at the part that connects to the tip portion. The susceptor according to claim 1.

6. A linearly extending flat portion is provided on the outer circumferential surface of the wafer. The distance between the two intersection points on one and the other side of the circumferential direction between the rotation-stopping portion and the virtual circle is shorter than the length dimension of the flat portion as viewed from the axial direction. The susceptor according to claim 1.

7. A susceptor comprising the one described in any one of claims 1 to 6, SiC epitaxial growth apparatus.

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