JP6601956B2 - Wafer support, SiC epitaxial wafer manufacturing apparatus and method including the same - Google Patents

Description

  The present invention relates to a wafer support and a manufacturing apparatus and a manufacturing method of a SiC epitaxial wafer including the same.

  As a means for forming a thin film on a substrate, various film forming methods such as a sputtering method, a vacuum evaporation method, and a chemical vapor deposition (CVD) method are generally used.

When a chemical vapor deposition method is used, a high quality film can be formed. Since the performance of semiconductor devices, etc. varies when the thickness and composition of the film to be formed and the concentration of added impurities vary, there is a demand for particularly high-quality films. A chemical vapor deposition method is generally used as a film forming method.
For example, a SiC epitaxial wafer uses a SiC single crystal substrate processed from a SiC bulk single crystal produced by a sublimation method or the like as a substrate on which a SiC epitaxial film is formed. Usually, a chemical vapor deposition method (CVD) is formed thereon. To grow a SiC epitaxial film which becomes an active region of the SiC semiconductor device.

In such an epitaxial wafer manufacturing process, flattening the surface of the wafer has been a long-standing issue, and in order to increase the effective area of the wafer, edge exclusion (from the invalid area around the semiconductor wafer, usually the edge) It is desired to increase the size of the wafer.
If the edge exclusion can be reduced, the effective area ratio of the chip can be increased and the yield of the semiconductor chip can be improved. For this reason, in recent years, it has been required to further reduce the width of edge exclusion.

  However, in crystal growth, it is observed that the growth rate differs between the center and the outer periphery of the wafer even when the wafer is placed in a space under the same conditions. It is known that when an epitaxial growth is performed on a single crystal wafer, a so-called epicrown is generated in which the outer peripheral portion becomes thick. Such an epicrown is required to be removed because it increases the width of edge exclusion.

Here, “the width of the edge exclusion increases” does not simply increase due to the influence of the film thickness difference in the outer peripheral portion where the epicrown is formed. For example, if an epicrown is formed on the upstream side of the step flow, homogeneous gas supply may be hindered, and defects due to various transitions may occur in the epitaxial film of the epitaxial wafer. The accompanying increase in the width of edge exclusion is also conceivable.
In addition, the epicrown is required to be removed because it may break during transportation and damage the epitaxial surface of the wafer or cause cracks during processing.

Conventionally, the elimination of the epi-crown is to remove the outer peripheral portion of the wafer in advance in accordance with the growth of the epi-crown so that the outer peripheral portion of the epitaxial wafer does not become thick (for example, Patent Document 1). Has been done. Further, the formed epicrown is removed after epitaxial growth (for example, Patent Document 2).
Further, in a chemical vapor deposition apparatus, a wafer (substrate) on which an epitaxial film is grown is usually provided in a susceptor (substrate support member) provided with a recess (such as a counterbore). It has been common to reduce the level difference because of the concern that the gas flow may be disturbed at the level difference between the surface and the surface of the susceptor (for example, Patent Document 3). Therefore, in the epitaxial growth of silicon, the depth of the concave portion of the susceptor is changed according to the thickness of the silicon wafer so that the step between the upper surface of the susceptor and the upper surface of the silicon wafer is reduced. (Patent Document 4).

JP 7-226349 A JP 2014-27006 A JP-A-4-354119 Japanese Patent Laid-Open No. 2003-12397

  However, in the method of removing a part of the outer peripheral portion in advance as in Patent Document 1, for example, the outer peripheral portion is removed in accordance with the thickness of the epitaxial film to be formed and the thickness of the epicrown formed at that time. Therefore, it becomes a dedicated wafer for forming an epitaxial film having a specific thickness. In an actual production site, it is common to change the epitaxial film to be grown depending on the application and conditions, and using a wafer dedicated to specific film formation conditions significantly deteriorates the production efficiency.

  In addition, for example, when the epicrown is removed after growing the epitaxial film as in Patent Document 2, the vicinity of the removed epicrown is shaved by polishing, which causes a problem that the epitaxial film becomes rough due to damage during polishing. A semiconductor device laminated on such a polished surface is inferior in performance and cannot be used as a product. That is, it is impossible to solve the problem of reducing edge exclusion for the purpose of removing the epicrown.

  Further, there is a problem that man-hours are required to remove the epicrown regardless of which method is used. There was a problem that the yield was also lowered because cracking was likely to occur in the processing. In addition, there is a problem that particles generated during polishing adhere to the surface of the epitaxial film and cause defects in the semiconductor device.

As described above, conventionally, there has been no actual proposal for an apparatus that can efficiently and sufficiently suppress the epicrown that occurs when an epitaxial film is grown on a wafer. Moreover, the actual situation is that there has not been a sufficient proposal for an epitaxial wafer that can sufficiently reduce edge exclusion.
For this reason, the manufacturing apparatus which can reduce an epicrown efficiently and fully has been calculated | required earnestly.

Also, the manufacture of the SiC epitaxial wafer is performed so as to pass over the SiC substrate from the outside of the outer peripheral edge of the SiC substrate using a Si atom-containing gas such as SiH ₄ and a C-containing source gas such as C ₃ H ₈ as process gases. Gas is being supplied to. At this time, the epitaxial film is grown by depositing an epitaxial material on the substrate while maintaining the SiC single crystal substrate at a high temperature by the heating means.
However, when the SiC epitaxial film is grown on the SiC substrate, the carrier concentration becomes too high in the outer peripheral portion of the SiC epitaxial film, that is, near the edge, and the variation of the carrier concentration in the surface of the SiC epitaxial film becomes large. was there.

As a result of intensive studies on the cause of the carrier concentration variation as described above, the present inventors have found that propane (C ₃ H ₈ ) and silane-based gas (generally used as raw material gases for SiC epitaxial films) It has been found that the cause of this is that the decomposition rate is greatly different from that of SiH ₄ ).
It is known that C ₃ H ₈ containing carbon has a slower decomposition rate than SiH ₄ . In addition, when the source gas is supplied onto the SiC substrate during epitaxial growth, the SiC substrate is rotating, so that the outer peripheral end of the SiC substrate is close to the gas inlet (upstream side of the gas flow). That is, when the SiC epitaxial film grows with the supply of these source gases, the decomposition of C ₃ H ₈ containing carbon is not sufficiently advanced in the vicinity of the outer peripheral portion of the SiC substrate on the upstream side of the gas flow. The carbon contained in the growth film is reduced. On the other hand, in the vicinity of the substrate center on the downstream side, the decomposition of C ₃ H ₈ containing carbon proceeds sufficiently, so that the carbon ratio increases relatively as compared with the vicinity of the outer peripheral portion.
The C / Si ratio of the raw material gas to be supplied is set on the assumption that propane (C ₃ H ₈ ) and silane-based gas (SiH ₄ ) are sufficiently decomposed. Accordingly, the C / Si ratio is relatively low in the outer peripheral portion of the SiC epitaxial film. That is, in the vicinity of the center of the substrate where the decomposition has progressed sufficiently, the carrier concentration in the plane of the SiC epitaxial film is appropriately controlled, while the C / Si ratio is lowered at the outer peripheral portion, and the carrier concentration is increased. is there.

  A description will be given of the fact that the carrier concentration increases in the outer peripheral portion because the C / Si ratio is low in the outer peripheral portion. In SiC epitaxial growth, N is generally used as a carrier, but this N is selectively introduced into a site occupied by carbon atoms. When the C / Si ratio is low, the amount of carbon in the source gas is relatively low, so that N serving as a carrier easily enters a site occupied by carbon in the epitaxially grown SiC film. That is, the uptake of N as a carrier increases and the carrier concentration increases. Therefore, in the conventional method, there is a problem that the carrier concentration in the outer peripheral portion of the SiC epitaxial film becomes high and the variation becomes large.

  Here, since the amount of carbon in the outer peripheral portion is insufficient, the carrier concentration becomes low. For example, by increasing the carbon concentration of the source gas, the C / Si ratio in the outer peripheral portion of the SiC epitaxial film is increased. Can be considered. However, by simply increasing the carbon concentration, the C / Si ratio at the center varies, and the carrier concentration difference between the wafer center and the outer periphery cannot be suppressed.

  The present invention has been made in view of the above problems, and a support base capable of efficiently and sufficiently reducing the epicrown and achieving a uniform carrier concentration in the wafer surface, and an SiC including the same. An object of the present invention is to provide an epitaxial wafer manufacturing apparatus and a manufacturing method.

As a result of intensive studies, the present inventors paid attention to the positional relationship between the upper surface on the reaction space side of the support member for supporting the wafer when growing the epitaxial film and the main surface of the wafer. The “wafer main surface” means a flat surface on which an epitaxial film is formed. When the chamfered portion is formed at the wafer end, the inclined surface of the chamfered portion is not called the main surface.
In the chemical vapor deposition apparatus, the wafer main surface on which the epitaxial film is grown and the support member formed around the wafer do not disturb the laminar flow supplied into the reaction space, so as not to generate a step as much as possible. Was common. Further, even if a step is provided, it is common knowledge for engineers in the field to suppress it to about several hundred μm.
However, the present inventors, when growing the epitaxial film, the portion of the upper surface on the reaction space side of the support member for supporting the wafer that is farthest from the wafer mounting surface, the main surface of the wafer on which the epitaxial film is grown, It was found that the epi-crown can be efficiently and sufficiently reduced by setting the step of 1 mm or more, which is a value that can be regarded as insane for engineers in the field, and completed the present invention.
That is, the present invention provides the following means in order to solve the above problems.

(1) The wafer support of the present invention is a wafer support used in a chemical vapor deposition apparatus for growing an epitaxial film on the main surface of the wafer by chemical vapor deposition, and the wafer support is The wafer has a wafer placement surface on which the substrate is placed and a wafer support portion that stands up so as to surround the periphery of the wafer to be placed. The height from the part far from the mounting surface to the main surface of the wafer mounted on the wafer mounting surface is 1 mm or more, and at least a part of the wafer support part is a part of the constituent elements of the epitaxial film. It consists of the material which contains.

(2) In the wafer support base of (1), it is preferable that the wafer is a SiC single crystal substrate, the epitaxial film is a SiC epitaxial film, and at least a part of the wafer support portion is made of graphite.
(3) In the wafer support base of (1) or (2), the wafer support portion is made of graphite, and a coating layer is formed on at least a part of the wafer support base portion and is not covered with the coating layer. The graphite is exposed in the portion.

(4) A SiC epitaxial wafer manufacturing apparatus according to the present invention is a SiC epitaxial wafer manufacturing apparatus for growing a SiC epitaxial film on a main surface of a SiC substrate by a chemical vapor deposition method. And a wafer support base according to any one of (1) to (3) above, wherein the wafer support plate is disposed in the concave accommodating portion and on which the SiC substrate is placed.
(5) In this invention, it is preferable that the flow velocity of the gas supplied with respect to the main surface of the SiC substrate mounted on the said wafer support stand is 0.1m / s-10m / s.

(6) A manufacturing method of the present invention is a manufacturing method of a SiC epitaxial wafer in which a SiC epitaxial film is grown on a main surface of a SiC substrate by a chemical vapor deposition method, and includes a mounting plate having a concave housing portion, Using the SiC epitaxial wafer manufacturing apparatus provided with the wafer support base according to any one of (1) to (3) above, wherein the wafer is disposed in the concave accommodating portion and on which an SiC substrate is placed. A SiC epitaxial film is formed on the SiC substrate while generating a flow of a source gas that reaches the main surface of the SiC substrate after getting over the support portion.
(7) In the manufacturing method of this invention, it is preferable that the flow velocity of the gas supplied with respect to the main surface of the SiC substrate mounted on the said wafer support stand is 0.1m / s-10m / s.

  The wafer support provided in the wafer support of the present invention is from the portion farthest from the wafer mounting surface on the upper surface on the reaction space side of the wafer support to the main surface of the wafer mounted on the wafer mounting surface. Is 1 mm or more in height. Therefore, it is possible to suppress the source gas from being supplied to the outer peripheral portion of the wafer, to suppress the growth of the epicrown, and to obtain an epitaxial wafer having a large effective area with a small edge exclusion width. In addition, since at least a part of the wafer support base contains a part of the constituent elements of the epitaxial film, elements necessary for the growth of the epitaxial film can be supplied from the wafer support part, and the carrier concentration varies in the in-plane direction. It is possible to provide an epitaxial wafer including an epitaxial film that suppresses the above.

  According to the manufacturing apparatus and the manufacturing method of the present invention, the above-described wafer support portion is provided. Therefore, by using the manufacturing apparatus and the manufacturing method of the present invention, the epicrown can be efficiently and sufficiently reduced, and the SiC epitaxial wafer having a large effective area with a small edge exclusion width is obtained. A SiC epitaxial wafer having a uniform carrier concentration can be obtained.

It is sectional drawing which illustrates typically the manufacturing apparatus of the SiC epitaxial wafer which is one Embodiment of this invention. It is the schematic diagram which planarly viewed the mounting plate of the manufacturing apparatus of the SiC epitaxial wafer which is one Embodiment of this invention. It is a cross-sectional schematic diagram which shows 1st Embodiment of the wafer support stand which concerns on this invention. It is a cross-sectional schematic diagram which shows 2nd Embodiment of the wafer support stand which concerns on this invention. It is a cross-sectional schematic diagram which shows 3rd Embodiment of the wafer support stand which concerns on this invention. It is a cross-sectional schematic diagram which shows 4th Embodiment of the wafer support stand which concerns on this invention. It is a cross-sectional schematic diagram which shows 5th Embodiment of the wafer support stand which concerns on this invention. It is a cross-sectional schematic diagram which shows 6th Embodiment of the wafer support stand which concerns on this invention. It is the cross-sectional schematic diagram which cut | disconnected the epitaxial wafer which has an epicrown in the cross section which passes along the center. It is a cross-sectional SEM (scanning electron microscope) image which expanded the wafer peripheral part in which the epicrown was formed. It is a cross-sectional schematic diagram of the arbitrary cross sections which pass along the wafer center of the epitaxial wafer which concerns on one Embodiment of this invention. It is a SEM (scanning electron microscope) image which expanded the cross section of the peripheral part of the epitaxial wafer which concerns on one Embodiment of this application. It is a figure for demonstrating Example 7 and Example 8 of this invention, (a) is a graph which shows distribution of the carrier concentration in the radial direction of a SiC epitaxial wafer, (b) is with respect to the carrier concentration of a wafer center. It is the graph which showed ratio of the carrier concentration in the radial direction of a SiC epitaxial wafer.

Hereinafter, a wafer support unit, a SiC epitaxial wafer manufacturing apparatus, and a SiC epitaxial wafer manufacturing method to which the present invention is applied will be described in detail with reference to the drawings as appropriate.
In the drawings used in the following description, in order to make the characteristics of the present invention easier to understand, the characteristic parts may be shown in an enlarged manner for the sake of convenience, and the dimensional ratios of the respective components are different from actual ones. Sometimes. In addition, the materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited to them, and can be appropriately changed and implemented without changing the gist thereof.
In the present invention, the term “wafer” may refer to a single crystal substrate wafer before epitaxial growth or a wafer having an epitaxial film. Also, a wafer in the middle of epitaxial growth may be described as a “wafer”. In particular, when distinguishing wafers after epitaxial growth, they are described as “epitaxial wafers”.

(SiC epitaxial wafer manufacturing equipment, wafer support)
FIG. 1 is a diagram schematically illustrating a cross section of a SiC epitaxial wafer manufacturing apparatus according to an embodiment of the present invention. Although the SiC epitaxial wafer manufacturing apparatus of the present invention is not limited to the configuration of FIG. 1, the present invention will be described based on the manufacturing apparatus of FIG. 1 for easy understanding.
The SiC epitaxial wafer manufacturing apparatus 100 according to the present embodiment, for example, deposits and grows a layer on the surface of the heated wafer W while supplying the source gas G into a chamber (deposition chamber) that can be evacuated under reduced pressure. It is a device to let you. For example, when SiC is epitaxially grown, silane (SiH ₄ ), dichlorosilane (SiCl ₂ H ₂ ), trichlorosilane (SiCl ₃ ), silicon tetrachloride (SiCl ₄ ) or the like is used as the source gas G for the source gas G. Propane (C ₃ H ₈ ), ethane (C ₂ H ₆ ), or the like can be used as the carbon (C) source. A carrier gas containing hydrogen (H ₂ ) or the like can be used.

This manufacturing apparatus 100 is opposed to the upper surface of the mounting plate 10 so as to form a reaction space K between the mounting plate 10 on which a plurality of wafers W are mounted and the mounting plate 10 inside the chamber. The sealing (top plate) 50 is disposed, and the peripheral wall 60 is disposed outside the wafer support 20 and the sealing 50 so as to surround the reaction space K. In this example, a plurality of wafer support tables 20 are installed on the upper surface side of the mounting plate 10 as will be described later.
An induction coil (heating means) 70 is provided around the mounting plate 10 and the ceiling 50 so as to surround them.
When a high frequency current is supplied to the induction coil 70 from a high frequency power supply (not shown), the mounting plate 10 and the ceiling 50 are heated by high frequency induction heating. The wafer W placed on the wafer support table 20 can be heated by radiation from the mounting plate 10 and the ceiling 50, heat conduction from the wafer support table 20, or the like. The heating means is not limited to the configuration disposed on the lower surface side of the mounting plate 10 (the turntable 13) and the upper surface side of the ceiling 50, and may be configured to be disposed only on either one of these. is there. Further, not only high-frequency induction heating but also resistance heating or the like may be used.

  A gas introduction pipe 30 is provided so as to penetrate the center of the ceiling 50 vertically, and the raw material gas G discharged from the gas introduction pipe 30 is radially supplied to the wafer W from the center side to the outside of the reaction space K. By flowing, the source gas G can be supplied in parallel to the surface of the wafer W. The gas that is no longer necessary in the chamber can be discharged out of the chamber through an exhaust port (not shown) provided outside the peripheral wall 60.

The mounting plate 10 employs a so-called planetary (self-revolving) system, and a rotating shaft 12 is connected to the center of the bottom of the mounting plate 10. When the rotary shaft 12 is rotationally driven by a drive motor (not shown), the mounting plate 10 is also rotated around its central axis and the mounting plate 10 integrated on the rotary base 13 is also rotated. Driven.
On the upper surface side of the mounting plate 10, a plurality of concave accommodating portions 11 are provided in a circular shape in a plan view and arranged in a plurality at equal intervals in the circumferential direction (rotating direction) of the rotating shaft 12. FIG. 2 is a schematic view in plan view of the mounting plate 10 of the manufacturing apparatus 100. The case where the six recessed accommodating parts 11 are provided along with the circumference of the mounting plate 10 at equal intervals is illustrated.

The wafer support 20 is accommodated in the concave accommodating portion 11 of the mounting plate 10 as shown in FIG. 2, and the wafer W can be placed on the upper surface. In FIG. 2, for the sake of simplification, a state in which the wafer support 20 is accommodated only in the two concave accommodating portions 11 of the mounting plate 10 is shown, but the configuration is not limited thereto.
The wafer support table 20 is rotationally driven around the central axis of the wafer support table 20 when a driving gas different from the source gas G is supplied between the lower surface of the wafer support table 20 and the concave accommodating portion 11. (Not shown). Thereby, since each wafer support stand 20 is rotated separately from the rotation of the mounting plate 10, film formation can be performed uniformly on the wafer W placed on the wafer support stand 20.

FIG. 3 is a schematic cross-sectional view of the AA ′ plane (FIG. 2) of the wafer support according to the embodiment of the present invention. The wafer support 20 includes a disk-shaped wafer mounting unit 21 on which a substrate is mounted on an upper surface 21a, and a ring-shaped wafer support unit 22 standing so as to surround the periphery of the wafer W to be mounted. . The wafer mounting portion 21 is formed with a peripheral step portion 21b on the peripheral upper surface side, and a ring-shaped wafer support portion 22 is inserted into the peripheral step portion 21b, and the wafer mounting portion 21 and the wafer support portion are integrated. 22 are both accommodated in the concave accommodating portion 11.
As an example, the wafer mounting portion 21 may employ a structure in which the outer peripheral surface of a disk made of graphite is covered with a TaC or SiC film. The wafer support portion 22 is made of graphite as an example.

A height h from the portion farthest from the wafer placement surface 21a to the main surface Wa of the wafer W placed on the wafer placement surface 21a on the upper surface 22a on the reaction space K side of the wafer support portion 22 is 1 mm or more. The height h is preferably 1.5 mm or more, and more preferably 2 mm or more. The height h is preferably 5 mm or less.
If the height h from the portion farthest from the wafer placement surface 21a on the upper surface 22a on the reaction space K side of the wafer support portion 22 to the main surface Wa of the wafer W placed on the wafer placement surface 21a is 1 mm or more. The source gas can be suppressed from being supplied to the outer peripheral portion of the wafer, and the epicrown can be prevented from growing.
The ratio of the crown height to the epi layer thickness can be reduced as the height h is greater than 1 mm. Further, if the height h is more than 5 mm, the laminar flow of the gas supplied into the chemical vapor deposition apparatus is disturbed, which is not preferable.
Here, “the portion farthest from the wafer placement surface on the upper surface on the reaction space side” means the portion of the wafer support portion that is farthest from the wafer placement surface in the vertical direction. In addition, the wafer shown by “the main surface Wa of the wafer W placed on the wafer placement surface 21 from the portion farthest from the wafer placement surface on the upper surface 22a on the reaction space K side” is basically a single crystal substrate. The main surface.
Since the thickness of the single crystal substrate is constant and the main surface is flat, it can be clearly defined.
On the other hand, epitaxial growth basically grows while maintaining surface uniformity below a certain value. Further, since the epitaxial film to be grown is thinner than the thickness of the single crystal substrate, the epitaxial film may be regarded as the main surface of the epitaxial wafer during and after the growth. In other words, the distance between the main surface of the epitaxial wafer surface on which the target epitaxial film is formed and the uppermost surface on the reaction space side of the wafer support portion farthest from the wafer mounting surface may be 1 mm or more.

In the case of FIG. 3, since the upper surface 22a is a plane parallel to the wafer placement surface, any point on the upper surface 22a is the portion farthest from the wafer placement surface.
The term “height” used herein means the length of a perpendicular line extending from the portion of the upper surface on the reaction space side that is farthest from the wafer placement surface onto the extended line of the wafer placement surface.
The epicrown is a portion where the film thickness of the epitaxial film formed on the periphery of the epitaxial film grown on the epitaxial substrate is thick.
In the case of FIG. 3, the wafer support portion 22 is drawn in a rectangular cross section, but it may be a triangular cross section.

Conventionally, in conventional epitaxial growth of silicon or the like, if the height is about several hundred μm or more, it is expected to disturb the laminar flow of the gas, and it has not been considered to exceed the range. However, this time, it was found that there is no difference in the performance of the epitaxial film formed on the wafer W even if it has a step of about several mm contrary to expectation. At this time, the inventors have found that the epicrown can be efficiently inhibited from growing at the same time.
The effect of such a level difference is particularly small when the growth pressure is a low pressure of 25 kPa or less and the growth temperature is as high as 1400 ° C. or more, and there is a difference in the performance of the epitaxial film formed on the wafer W. Hardly occurs. That is, in the case of the SiC epitaxial film manufactured under the above-mentioned conditions, it means that it is not easily affected by the step.

FIG. 3 is a schematic cross-sectional view of the AA ′ plane (FIG. 2) including the mounting plate around the wafer support base according to the embodiment of the present invention.
As shown in FIG. 3, the height H from the highest point of the upper surface 22a on the reaction space K side of the wafer support 22 to the upper surface 10A on the reaction space K side of the mounting plate 10 is −1 mm or more and 5 mm or less. Preferably, it is 0 mm or more and 2 mm or less.
If the height exceeds 5 mm, the laminar flow of the gas supplied from the plane parallel to the mounting plate 10 is disturbed by the step, making it difficult to grow a homogeneous epitaxial film.

In the wafer support portion 22 of the present embodiment, the whole is made of graphite and the entire surface of the graphite of the wafer support portion 22 is exposed. However, as shown by the oblique lines in FIG. The covering layer 22b may be formed on the peripheral edge, the lower surface, and the lower edge peripheral edge, respectively, and the upper surface side graphite of the wafer support portion 22 and the lower surface side graphite of the wafer support portion 22 may be partially covered. A thin film of metal carbide such as TaC can be used as the coating layer.
By covering the graphite on the upper surface side and the lower surface side of the wafer support portion 22, the area where the graphite is exposed can be reduced, so that the carbon supply from the wafer support portion 22 during film formation depends on the size of the area covered by the coating layer 22b. The amount can be adjusted to the desired amount.

  Wafer support portion 22 preferably includes the same material as the epitaxial film formed on the main surface of wafer W. If the wafer support part 22 contains the same material as the epitaxial film formed on the main surface of the wafer W, even if a part of the wafer support part 22 sublimates, it is formed on the main surface of the wafer W. The influence on the epitaxial film can be suppressed. In the case of epitaxial growth, a reaction occurs in a portion other than on the wafer W, and deposits are deposited. By including the same material as the epitaxial film as the material of the wafer support portion 22, it is possible to suppress the difference in thermal expansion coefficient that occurs at the interface between the deposit and the adherend surface and prevent the deposit from peeling off and forming particles. it can. As a wafer support part containing the same material as the epitaxial film, the upper surface side of the wafer support part can be made of SiC polycrystal.

The flow rate of the gas supplied to the main surface Wa of the wafer W placed on the wafer support 20 is preferably 0.1 m / s to 10 m / s, and preferably 0.2 m / s to 5 m / s. It is more preferable that
If the flow rate of the gas supplied to the main surface Wa of the wafer W is more than 10 m / s, turbulent flow is likely to occur even with a slight level difference. That is, if the level difference between the upper surface 22a of the wafer support 22 and the main surface Wa of the wafer W is too large, turbulent flow is likely to occur.
Further, if the flow rate of the gas supplied to the main surface Wa of the wafer W is less than 0.1 m / s, it is desirable that the gas reacts on the wafer W and epitaxial growth is originally performed. A reaction occurs before it reaches, and deposits adhere to parts other than the wafer. These deposits cause particles by peeling.

The wafer support 22 is preferably arranged so as to follow along the periphery of the wafer W. For example, when the wafer W has an orientation flat (OF), the wafer support portion 22 is preferably formed so as to follow the shape of the orientation flat. A portion where the orientation flat of the wafer W is formed (hereinafter referred to as an orientation flat portion) exists inside the outer peripheral portion of the wafer W on which the epicrown grows when viewed in plan. If the wafer support portion 22 is formed in a circular shape without following the orientation flat shape, there is a distance between the orientation flat portion and the wafer support portion 22 in a plan view, and it becomes difficult to obtain a sufficient shielding effect by the wafer support portion 22. . That is, it becomes difficult to sufficiently suppress the epicrown formed in the orientation flat part.
Further, if there is a portion on the wafer placement surface 21 that is not covered by the wafer W, crystals are also deposited on that portion. This deposit may cause the wafer W to float with respect to the mounting surface. Therefore, by arranging the inner peripheral edge of the wafer support portion 22 so as to follow along the periphery of the wafer W, it is possible to prevent unnecessary crystals from being deposited on the mounting surface outside the orientation flat.

  The support portion 61 is a shielding plate support portion provided on the inner peripheral surface of the peripheral wall 60 over the entire circumference, and the outer peripheral portion of the sealing 50 is placed on the shielding plate support portion.

In the manufacturing apparatus 100 of this embodiment, by supplying the source gas G from the source gas introduction pipe 30 downward, from the outside of the outer peripheral end of the wafer W placed on the wafer support 20, The source gas G is supplied so as to pass over the main surface Wa of the wafer W. Then, an epitaxial film is deposited by depositing an epitaxial material on the wafer W while maintaining the wafer W at a high temperature by an induction coil (heating means) 70 made of a high-frequency coil or the like.
At this time, carbon (C) is generated from the wafer support portion 22 made of graphite with heating by the heating means, and on the upstream side in the gas flow of the raw material gas G, that is, on the F1 side of the arrow F shown in FIG. By supplying carbon toward, the C / Si ratio on the upstream (F1) side is increased.

As described above, since the hydrocarbon gas constituting the source gas G usually has a slower decomposition rate than Si contained in the silane gas, the SiC epitaxial film located on the upstream side of the gas flow of the source gas G in particular. There is a tendency that the C concentration becomes lower in the outer peripheral portion.
On the other hand, according to the manufacturing apparatus 100 of the present embodiment, by adopting the above-described configuration including the wafer support portion 22 made of graphite, carbon is directed toward the upstream (F1) side of the gas flow of the source gas G. By supplying, the C / Si ratio of the gas in the vicinity of the outer peripheral portion of the SiC epitaxial film can be increased, and the SiC epitaxial film can be grown. Thereby, the variation in the C / Si ratio in the plane of the SiC epitaxial film due to the difference in the decomposition rate of each component constituting the source gas G can be suppressed. Thus, with the reduction in the position dependency of the C / Si ratio of the gas in the entire plane of the SiC epitaxial film, the variation in the carrier concentration of the SiC epitaxial film can be reduced.
In the case of the self-revolving type apparatus as in the present embodiment, the gas spreads from the center to the outer peripheral side of the mounting plate and the source gas is also decomposed and consumed, so the growth rate of the SiC epitaxial film Becomes smaller toward the outer periphery of the mounting plate. Therefore, when attention is paid to the end portion on one side of the SiC substrate, the growth when it is on the center side has a larger contribution. When the wafer support 20 is rotating, it is averaged to some extent. However, as a substantial growth condition, the wafer peripheral part is on the upstream side of the gas by comparing the center part and the outer peripheral part of the wafer. The carrier concentration distribution reflects this.

The wafer support 20 is not limited to the configuration shown in FIG.
FIG. 4 shows a second embodiment of the wafer support base. The wafer support base 25 of the second embodiment includes a wafer mounting portion 21 equivalent to the previous embodiment and a double ring fitted on the outer peripheral portion thereof. It consists of a mold wafer support 26. The wafer support portion 26 includes a ring-shaped inner peripheral support member 26A provided on the inner peripheral side and a ring-shaped outer peripheral support member 26B provided on the outer peripheral side thereof.
In this example, the inner circumferential support member 26A and the outer circumferential support member 26B have the same height, and the above-described height h is defined by their upper surfaces 26a.
Support members 26A and 26B of the present embodiment are both made of graphite.
In this embodiment, for example, the graphite on the entire surface of the inner peripheral support member 26A is exposed, and the entire surface of the outer peripheral support member 26B is covered with a coating layer of SiC, TaC, or the like, and supplied from the wafer support 26 during film formation. The amount of carbon to be changed can be changed from the case of the previous embodiment. Further, the entire surface of the inner peripheral support member 26A may be covered with a coating layer such as SiC or TaC, and the graphite of the entire outer peripheral support member 26B may be exposed. With this configuration, the amount of carbon supplied from the wafer support 26 during film formation can be changed from the previous structure.

FIG. 5 shows a third embodiment of the wafer support, and the wafer support 27 according to the third embodiment comprises a wafer installation part 21 and a multi-ring type wafer support part 28 installed on the outer periphery thereof. . The wafer support portion 28 is provided on the inner circumferential upper and lower sides of the ring, and the ring-shaped inner circumferential lower support member 28A, inner circumferential upper support member 28B and rings provided on the outer circumferential side thereof are made of graphite. And an outer peripheral support member 28C.
In this structure, for example, the inner peripheral lower support member 28A is covered with a TaC or SiC coating layer, and the graphite of the inner peripheral upper support member 28B is exposed entirely, so that carbon can be supplied only from the inner peripheral upper support member 28B. It can be configured as follows.
Further, for example, by covering the inner peripheral upper side support member 28B with a TaC or SiC coating layer and exposing the entire surface of the inner peripheral lower side support member 28A, carbon can be supplied only from the inner peripheral lower side support member 28A. Can be configured.
In this embodiment, any one of the inner peripheral lower side support member 28A, the inner peripheral upper side support member 28B, and the outer peripheral side support member 28C may be covered with a coating layer, or any of them may be exposed. The amount of carbon supplied during film formation can be adjusted by changing the support member covered with the coating layer.

FIG. 6 shows a fourth embodiment of the wafer support base, and the wafer support base 32 of this fourth embodiment comprises a wafer installation portion 21 and a ring-type wafer support portion 33 installed on the outer periphery thereof. The wafer support portion 33 is entirely made of graphite, and a coating layer is formed on almost the entire surface thereof. A plurality of 33b are formed, and the graphite is partially exposed.
With this structure, the amount of carbon supplied during film formation can be adjusted to a target value by adjusting the exposed portion of graphite.
FIG. 7 shows a fifth embodiment of the wafer support base. The wafer support base 34 of the fifth embodiment includes a wafer installation portion 21 and a ring-type wafer support portion 35 installed on the outer periphery thereof. The wafer support portion 35 is provided so as to cover a graphite ring-shaped inner peripheral lower side support member 35A provided on the inner peripheral lower portion thereof and the upper and outer peripheral sides of the inner peripheral lower support member 35A. It consists of graphite outer peripheral side support members 35B. An inner peripheral step portion 35C is formed on the inner peripheral lower portion side of the outer peripheral side support member 35B, and the inner peripheral lower portion support member 35A is integrated so as to be fitted to the inner means portion 35C.

In this structure, for example, the inner peripheral lower support member 35A is covered with a TaC or SiC coating layer, and the graphite of the outer peripheral support member 35B is exposed to the entire surface, so that carbon can be supplied only from the outer peripheral support member 35B. .
Further, for example, the outer peripheral support member 35B is covered with a TaC or SiC coating layer, and the graphite of the inner peripheral lower support member 35A is exposed to the entire surface, so that carbon can be supplied only from the inner peripheral lower support member 35A. it can.

FIG. 8 shows a sixth embodiment of the wafer support, and the wafer support 36 of this sixth embodiment is installed on the portion of the wafer installation section 21 used in the previous embodiment and on the outer periphery thereof. A ring-shaped outer peripheral support member is integrated, and the whole is made of graphite. That is, it is composed of a disk-shaped wafer mounting portion 36A and a ring-shaped wafer support portion 36B integrally formed on the outer peripheral portion thereof. The upper surface of the wafer installation portion 36A is the wafer installation surface 36C, and the upper surface 36a of the wafer support portion 36B. Defines the height h described above.
In the configuration of FIG. 8, since the entire wafer support 36 is made of graphite, a structure suitable for supplying more carbon than in the previous embodiment is obtained.

As described above, the wafer support can take various forms.
In addition, the cross-sectional shape of the wafer support portion of each embodiment on the AA ′ plane does not need to be a quadrangle as shown in FIGS. 3 to 8 and may be a triangle or the like.

(Epitaxial wafer)
FIG. 9 is a schematic cross-sectional view when an epitaxial film is provided on a wafer and the epitaxial film has a flat portion and an epicrown. FIG. 10 is an SEM (scanning electron microscope) image (cross-sectional SEM image) in which the cross section of the peripheral portion of the epitaxial wafer on which the epicrown is formed is enlarged. As shown in FIG. 9, an epitaxial film E is stacked on the wafer W.
The epitaxial film E has a flat portion Ef and an epicrown Ec. The epitaxial film E is basically formed flat, and the thickness of the flat portion Ef is substantially uniform, and the thickness is in the range of ± 5% with respect to the thickness at the center C. On the other hand, the height of the epicrown Ec has a film thickness exceeding 40 to 100% with respect to the film thickness at the center of the wafer.
Here, the height of the epi crown is the height h _e from the level surface of the epitaxial layer surface on the main surface (line b in FIG. 10) to the top surface or apex of the epi crown (line a in FIG. 10) .

The level surface is an ideal surface on which an epitaxial wafer is formed and is a level surface. Originally, it is ideal that the epitaxial film has the same film thickness at the center and other parts. The level surface means a surface that is vertically separated from the main surface (line c in FIG. 10), which is the outermost surface of the substrate wafer, by the epitaxial film thickness at the center of the wafer when the main surface of the substrate wafer is used as a reference. . In other words, “the height from the level surface to the top surface (vertex) of the epicrown” means the width of the vertical line drawn from the top surface (vertex) of the epicrown to the level surface of the wafer. Note that when the edge of the substrate wafer is chamfered, even if the top surface (vertex) of the epicrown is present on the surface of the epitaxial layer grown on the chamfered portion, the surface of that portion of the epicrown The height from the top surface (vertex) to the level surface of the surface of the epitaxial layer on the extrapolated main surface may be the height of the epicrown.
The wafer peripheral portion means a portion around the wafer that has a great influence on device fabrication. When the OF is formed on the wafer, the vicinity of the OF is removed with a certain width for device fabrication, so the influence on the product quality of the crown is practically small, so the “OF part” is included in the peripheral part of the wafer. It does not have to be.

  When the epicrown Ec is provided, the width of the edge exclusion is increased, and the effective area ratio at which the chip can be taken is reduced. There is also a possibility of causing various defects. Further, when the height is large, inconvenience occurs in the device forming process. Here, the film thickness means the film thickness of the epitaxial film in a direction perpendicular to the main surface Wa of the wafer W. The film thickness and epicrown height can be measured from a cross-sectional SEM image as shown in FIG.

FIG. 11 is a schematic cross-sectional view of an arbitrary cross section passing through the wafer center of the epitaxial wafer according to one embodiment of the present invention.
The epitaxial wafer according to an embodiment of the present invention has an epitaxial film E on the main surface Wa of the wafer W, and the height of the epicrown is within 30% of the film thickness of the epitaxial film at the wafer center C. is there.

FIG. 12 is an SEM (scanning electron microscope) image in which the cross section of the peripheral portion of the epitaxial wafer according to an embodiment of the present application is enlarged. The photographed part is not the OF part of the wafer but the peripheral part where the OF is not formed. Since the edge of the wafer is chamfered, the corners of the surface are rounded. In the photograph of FIG. 12, since the peripheral part on the image is difficult to see, the part corresponding to the peripheral part is traced with a dotted line.
The surface of the peripheral portion of the wafer is on the extension of the level surface that is the surface of the main surface, the height of the epicrown is 0, and the generation of the epicrown is suppressed. In FIG. 12, the portion surrounded by the alternate long and short dash line is unevenness or the like generated during cleavage, and is not an epicrown. Since the SiC single crystal is very hard, such unevenness may be observed at the time of cleavage, but it can be clearly determined by confirming that it is not an epicrown while changing the magnification or the like.

  The film thickness of the epitaxial film at the center of the wafer is preferably 30 μm or more. If the thickness of the epitaxial film is 30 μm or more, a high breakdown voltage device can be manufactured. In particular, a device using an epitaxial film made of SiC is particularly preferable because high pressure resistance is required.

  The epitaxial film E is not particularly limited, and may be Si, SiC, a III-V group compound, or the like. Further, the wafer W is not particularly limited. However, it can be preferably applied to epitaxial growth of SiC having a particularly high growth temperature and a low growth pressure.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

  Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

Example 1
As a wafer, a 4-inch (0001) Si surface 4 ° off SiC substrate having a thickness of 350 μm with OF was used and placed on a wafer support of a planetary chemical vapor deposition apparatus. At this time, a ring-shaped member made of graphite was disposed as a wafer support portion around the wafer. The ring-shaped member having a thickness of 2 mm was used. The cross-section of the ring-shaped member is a quadrangle, and the height from the upper surface on the reaction space side to the main surface of the wafer placed on the wafer placement surface was 1.65 mm. The ring member was provided with a straight line portion at a position corresponding to the OF portion of the wafer so that the inside of the ring member followed along the periphery of the wafer. The distance between the wafer outer periphery and the ring member was set to 0.15 mm.
As the source gas, a mixed gas of silane and propane is used, and hydrogen gas is used as the carrier gas. The growth pressure is 15 kPa, the growth temperature is 1600 ° C., and the flow rate toward the wafer is 2 m / s at the portion corresponding to the center of the wafer. Supplied.
Under such conditions, the epitaxial film was grown 30 μm on the flat portion, and the height of the epicrown formed at that time was measured. As a result, the height of the epicrown formed on the OF surface of the SiC substrate was 6 μm, and the thickness of the epicrown on the outer peripheral surface other than the OF surface was 6 μm.

(Example 2)
The thickness of the epicrown was measured under the same conditions as in Example 1 except that the inside of the ring-shaped member was circular and no OF portion was provided.
As a result, the height of the epicrown formed on the OF surface of the SiC substrate was 24 μm, and the height of the epicrown on the outer peripheral surface other than the OF surface was 8 μm.

(Example 3)
The thickness of the epicrown was measured under the same conditions as in Example 2 except that the wafer was a SiC substrate having a thickness of 500 μm.
As a result, the height of the epicrown formed on the OF surface of the SiC substrate was 32 μm, and the thickness of the epicrown on the outer peripheral surface other than the OF surface was 9 μm.

(Examples 4 to 6)
The thickness of the epicrown was measured under the same conditions as in Examples 1 to 3 except that the thickness of the ring-shaped member was 4 mm.
In Example 4, no epicrown was observed.
In Example 5, no epicrown was observed except in the OF portion.
In Example 6, no epi-crown was observed except for the OF portion, the thickness of the epi-crown formed on the OF surface of the SiC substrate was 20 μm, and the thickness of the epi-crown on the outer peripheral surface other than the OF surface was 0 μm. It was.

(Comparative Examples 1-3)
The thickness of the epicrown was measured under the same conditions as in Examples 1 to 3 except that the thickness of the ring-shaped member was 1 mm.
In Comparative Example 1, the thickness of the epicrown formed on the OF surface of the SiC substrate was 13 μm, and the thickness of the epicrown on the outer peripheral surface other than the OF surface was 13 μm.
In Comparative Example 2, the thickness of the epicrown formed on the OF surface of the SiC substrate was 29 μm, and the thickness of the epicrown on the outer peripheral surface other than the OF surface was 13 μm.
In Comparative Example 3, the thickness of the epicrown formed on the OF surface of the SiC substrate was 50 μm, and the thickness of the epicrown on the outer peripheral surface other than the OF surface was 20 μm.
The results of Examples 1 to 6 and Comparative Examples 1 to 3 are summarized in Table 1.

  As can be seen from Table 1, it can be seen that as the height from the upper surface of the wafer support portion to the main surface of the wafer increases, the thickness of the epicrown decreases. Moreover, in Examples 1-6 in which the height from the wafer support portion upper surface to the wafer main surface is 1 mm or more as compared with Comparative Examples 1-3, epicrowns other than the OF portion are suppressed, It can be seen that the height is within 30% of the film thickness at the center of the wafer. Further, the inner height of the ring member follows the periphery of the wafer, whereby the crown height can be suppressed over the entire periphery of the wafer peripheral portion.

[Example 7]
In Example 7, first, a lapping method using a diamond slurry in which the C surface of a SiC substrate (6 inch, 4H—SiC-4 ° off substrate) is the main surface and the average particle size of secondary particles is 0.25 μm. After polishing, CMP polishing was further performed.
In SiC epitaxial growth on the C plane, the carrier concentration is greatly affected by the C / Si ratio, so the carrier concentration distribution becomes large. This time, in order to show the effect of improving the carrier concentration distribution by the carbon member more significantly, a C-plane wafer was used.

Next, a SiC epitaxial film having a thickness of 5 μm was formed on the main surface (C surface) of the polished SiC substrate using a manufacturing apparatus (CVD film forming apparatus) as shown in FIG. At this time, the SiC substrate was placed on a wafer support (satellite) provided on the mounting plate, and the source gas was supplied together with the carrier gas while the SiC substrate was revolving.
Further, as the film formation conditions at this time, the growth temperature is 1600 ° C., hydrogen is used as the carrier gas, nitrogen is used as the dopant gas, propane is used as the C source gas, silane is used as the Si source gas, and C / Si The ratio was 1.1.

In this example, the wafer support of the type shown in FIG. 3 of the first embodiment was used. That is, the ring-shaped wafer support portion 22 is provided on the wafer placement portion 21.
At this time, the substrate of the wafer support 20 was made of ultra high purity graphite. In the wafer support 20, the wafer setting portion 21 is covered with a SiC coating layer, and graphite is not exposed. The wafer support portion 22 has a structure having a carbon supply source from which ultra-high purity graphite is exposed. In other words, the upper surface of the ring is SiC and has a structure with graphite below. The cross-section of the ring-shaped member is a quadrangle, and the height from the upper surface on the reaction space side to the main surface of the wafer placed on the wafer placement surface was 1.65 mm. The ring member was provided with a straight line portion at a position corresponding to the OF portion of the wafer so that the inside of the ring member followed along the periphery of the wafer. The distance between the wafer outer periphery and the ring member was set to 0.15 mm.
The commercially available ultra-high-purity graphite has impurities of B of 0.1 ppm wt, Mg of 0.001 ppm wt or less, Al of 0.001 ppm wt or less, Ti of 0.001 ppm wt or less, and V of 0.001 ppm. What was less than wt, Cr was 0.004 ppm wt or less, Fe was 0.02 ppm wt or less, Ni was about 0.001 ppm wt or less, and further baked to remove nitrogen was used. Therefore, elements other than carbon are rarely supplied.

Then, regarding the SiC epitaxial wafer obtained by the above procedure and having the SiC epitaxial film formed on the main surface of the SiC substrate, in the radial direction of the SiC epitaxial wafer, using the CV measuring device, the outer peripheral end portion to the central portion to the outer peripheral portion The carrier concentration was measured at a pitch of 10 mm toward the end, and the results are shown in the graphs of FIGS. 13 (a) and (b).
FIG. 13A is a graph showing the carrier concentration distribution in the radial direction of the SiC epitaxial wafer, and FIG. 13B is a graph showing the ratio of the carrier concentration in the radial direction of the SiC epitaxial wafer to the carrier concentration at the center of the wafer. It is.

[Comparative Example 4]
In Comparative Example 4, the same procedure as in Example 7 was used, except that the manufacturing apparatus used had a structure in which the entire surface of the ring serving as the wafer support 22 was SiC and had no exposed graphite. Then, an SiC epitaxial wafer was manufactured under the conditions.
Then, the carrier concentration was measured at a pitch of 10 mm from the outer peripheral end to the central portion to the outer peripheral end in the radial direction of the SiC epitaxial wafer by the same method as in Example 7, and the results are shown in FIG. And in the graph of (b).

[Evaluation results]
As shown in the graphs of FIGS. 13 (a) and 13 (b), using the manufacturing apparatus of the present invention, the SiC epitaxial film is formed on the main surface of the SiC substrate while supplying carbon upstream of the source gas. It can be seen that the SiC epitaxial wafer of Example 7 thus obtained has a uniform carrier concentration as compared with Comparative Example 4 over the entire surface.

Here, in Comparative Example 4, although a relatively low carrier concentration is shown in the vicinity of the wafer central portion, a very high carrier concentration is shown in the outer peripheral portion of the wafer (near the edge), and in the plane of the SiC epitaxial film. It can be seen that the carrier concentration is extremely uneven.
On the other hand, in Example 7, the carrier concentration variation was smaller than that in Comparative Example 4. As shown in FIG. 13B, in Comparative Example 4, the carrier concentration variation (difference in carrier concentration between the central portion and the outer peripheral portion) was 25% or more, whereas in Example 7, it was about 10%. there were.
In particular, in Example 7, the carrier concentration is controlled to be lower than that of Comparative Example 1 in the entire surface, and it can be seen that the carrier concentration is greatly reduced particularly in the outer peripheral portion of the wafer.

  From the above results, in the SiC epitaxial wafer manufactured in Example 7, the reason that the carrier concentration in the outer peripheral portion is particularly reduced is that the wafer support portion made of graphite is formed upstream of the source gas, that is, around the wafer. By installing the SiC epitaxial film under the condition of supplying carbon from here, the C / Si ratio is increased at the wafer outer periphery located upstream of the gas flow. It is thought that the concentration was lowered.

  DESCRIPTION OF SYMBOLS 100 ... Manufacturing apparatus, 10 ... Mounting plate, 10A ... Mounting plate upper surface, 11 ... Concave accommodation part, 12 ... Rotating shaft, 13 ... Rotating table, 20, 25, 27, 32, 34, 36 ... Wafer support table, 21, 36A ... Wafer mounting part, 21a, 36c ... Wafer mounting surface, 22, 26, 28, 33, 35, 36 ... Wafer supporting part, 22a, 26a, 28a, 33a, 35a, 36a ... Upper surface of wafer supporting part, 30 DESCRIPTION OF SYMBOLS ... Gas introduction pipe, 31 ... Gas introduction port, 50 ... Sealing, 60 ... Peripheral wall, 70 ... Induction coil, G ... Source gas, K ... Reaction space, W ... Wafer, Wa ... Wafer main surface, E ... Epitaxial film, Ef ... Flat part, Ec ... Epicrown, C ... Center, R ... Peripheral part.

Claims (6)

A SiC epitaxial wafer manufacturing apparatus for growing an epitaxial film on a main surface of a wafer by chemical vapor deposition,
A mounting plate having a concave accommodating portion; and a wafer support table disposed in the concave accommodating portion and on which an SiC substrate is placed.
The wafer support has a wafer placement surface on which a substrate is placed, and a wafer support portion that stands up to surround the wafer to be placed,
The height from the most distant from the wafer mounting surface on the upper surface on the reaction space side of the wafer support portion to the main surface of the wafer mounted on the wafer mounting surface is 1 mm or more,
A height from a portion farthest from the wafer mounting surface on the upper surface on the reaction space side of the wafer support portion to an upper surface on the reaction space side of the mounting plate is greater than 0 and 5 mm or less;
The SiC epitaxial wafer manufacturing apparatus, wherein at least a part of the wafer support part is made of a material containing a part of the constituent elements of the epitaxial film. 2. The SiC epitaxial wafer manufacturing apparatus according to claim 1, wherein the wafer is a SiC single crystal substrate, the epitaxial film is a SiC epitaxial film, and at least a part of the wafer support portion is made of graphite. The said wafer support part consists of graphite, and the coating layer was formed in at least one part of the said wafer support part, and graphite was exposed to the part which is not covered with the said coating layer. SiC epitaxial wafer manufacturing equipment . The flow rate of the gas supplied with respect to the main surface of the SiC substrate mounted on the said wafer support stand is 0.1 m / s-10 m / s, The any one of Claims 1-3 characterized by the above-mentioned. The SiC epitaxial wafer manufacturing apparatus according to the item . A SiC epitaxial wafer manufacturing method for growing a SiC epitaxial film on a main surface of a SiC substrate by chemical vapor deposition,
Using the SiC epitaxial wafer manufacturing apparatus according to any one of claims 1 to 3,
A SiC epitaxial film is formed on the SiC substrate while generating a flow of a source gas that reaches over the main surface of the SiC substrate after overcoming the wafer support portion. Production method. 6. The SiC epitaxial wafer according to claim 5 , wherein a flow rate of a gas supplied to a main surface of the SiC substrate placed on the wafer support is 0.1 m / s to 10 m / s. Manufacturing method.