Silicon carbide wafer manufacturing equipment

Abstract

To provide a SiC wafer manufacturing device capable of simplifying a shower head configuration.SOLUTION: A cooling portion 40 is capable of cooling a separation space 201 to 400°C or less, and supply pipes 51 to 53 include a dopant gas supply pipe 51 to which ammonia-based gas contained in reaction gas is supplied, a growth gas supply pipe 53 to which growth gas containing silane-based gas and chlorine-based gas contained in the reaction gas is supplied, and an inert gas supply pipe 52 to supply inert gas contained in the reaction gas between a portion of the separation space 201 to which the ammonia-based gas is supplied and a portion to which the chlorine-based gas is supplied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a manufacturing apparatus for SiC wafers made of silicon carbide (hereinafter also simply referred to as SiC). [Background technology]

[0002] Conventionally, a SiC wafer manufacturing apparatus has been proposed in which a seed substrate is placed on a susceptor and heated while being rotated in a reaction chamber into which a reactive gas containing a raw material gas is introduced, thereby growing an epitaxial layer, which is a semiconductor layer, on the surface of the seed substrate (see, for example, Patent Document 1).

[0003] Specifically, this SiC wafer manufacturing apparatus is equipped with a shower head that roughly divides the reaction chamber into a separation space to which a reaction gas is initially supplied and a growth space to which a seed substrate is placed. The shower head has a plurality of through-holes that communicate the separation space with the growth space. In this SiC semiconductor device, the reaction gas supplied to the separation space is supplied to the growth space through the plurality of through-holes, which facilitates uniform supply of the reaction gas onto the seed substrate.

[0004] The reaction gas contains a chlorine-based gas for growing the epitaxial layer and an ammonia-based gas as a dopant gas, etc. Therefore, the chlorine-based gas and the ammonia-based gas may react with each other in the separation space to produce solid ammonium chloride, which may clog the through-holes in the showerhead.

[0005] Therefore, the SiC wafer manufacturing apparatus is provided with partition walls for dividing the separation space into multiple spaces, and in the SiC semiconductor device, the chlorine-based gas and the ammonia-based gas are supplied to separate spaces, thereby making it difficult for solid ammonium chloride to be generated in the separation space. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-16008 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in such a SiC semiconductor device, the showerhead tends to have a complicated configuration due to the wall portion.

[0008] In view of the above, an object of the present invention is to provide a SiC wafer manufacturing apparatus that can simplify the configuration of the shower head. [Means for solving the problem]

[0009] The invention of claim 1 for achieving the above object is an apparatus for manufacturing SiC wafers, comprising: a cylindrical chamber (20) having an upper part (21) and a lower part (22) that constitutes a reaction chamber (200) to which a reaction gas is supplied and in which an epitaxial layer (11) made of SiC is grown on a surface (10a) side of a seed substrate (10) made of SiC; a susceptor (70) disposed in the lower part of the chamber and on which the seed substrate is disposed; supply pipes (51-53) connected to the upper part of the chamber that supply the reaction gas to the reaction chamber; and a supply pipe (51-53) disposed so as to divide the reaction chamber into a growth space (202) on the lower side and a separation space (201) on the upper side. The apparatus includes a shower head (30) having a plurality of through holes (31) that communicate the growth space and the separation space, and a cooling unit (40) that cools the separation space, and the cooling unit is capable of cooling the separation space to 400°C or less. The supply pipes include a dopant gas supply pipe (51) to which an ammonia-based gas contained in the reaction gas is supplied, a growth gas supply pipe (53) to which a growth gas containing a silane-based gas and a chlorine-based gas contained in the reaction gas is supplied, and an inert gas supply pipe (52) to supply an inert gas contained in the reaction gas between a portion of the separation space to which the ammonia-based gas is supplied and a portion to which the chlorine-based gas is supplied.

[0010] According to this, the separation space is cooled to 400°C or less by the cooling unit, which prevents silane gas from decomposing in the separation space to produce solid silicon, thereby preventing clogging of the through-holes of the showerhead. Furthermore, the inert gas supply pipe is arranged to supply inert gas between the portion of the separation space to which the ammonia-based gas is supplied and the portion to which the chlorine-based gas is supplied. Therefore, in the separation space, reaction between the ammonia-based gas and the chlorine-based gas can be prevented without the need for a partition wall or the like in the separation space, and clogging of the through-holes of the showerhead can be prevented. Therefore, in this SiC wafer manufacturing apparatus, clogging of the through-holes of the showerhead can be prevented without the need for a partition wall or the like that separates the separation space into multiple spaces, and the configuration of the showerhead can be simplified.

[0011] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing a manufacturing apparatus for a SiC wafer according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 10 is a schematic diagram showing a manufacturing apparatus for a SiC wafer according to a second embodiment. [Figure 4] FIG. 10 is a top view of a chamber in the third embodiment. [Figure 5] FIG. 10 is a schematic diagram showing a manufacturing apparatus for a SiC wafer according to a fourth embodiment. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] FIG. 10 is a schematic diagram showing a manufacturing apparatus for a SiC wafer according to a fifth embodiment. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. [Figure 9]FIG. 13 is a top view of a chamber in the sixth embodiment.

[0013] FIG. 2 is a cross-sectional view taken along line II-II in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following embodiments, parts that are identical or equivalent to each other will be denoted by the same reference numerals.

[0015] (First embodiment) A manufacturing apparatus (hereinafter also simply referred to as a manufacturing apparatus) 1 of a SiC wafer according to a first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a cross-sectional view taken along line II in Figure 2.

[0016] As shown in FIG. 1, the manufacturing apparatus 1 has a chamber 20 that constitutes a reaction chamber 200 in which an epitaxial layer 11 serving as a semiconductor layer is grown on a surface 10a side of a seed substrate 10 to manufacture an SiC wafer 12.

[0017] The chamber 20 is generally cylindrical and has an upper portion 21, a lower portion 22, and a side portion 23 connecting the upper portion 21 and the lower portion 22. The chamber 20 is provided with a shower head 30 that generally divides the reaction chamber 200 into a separation space 201 on the upper portion 21 side and a growth space 202 on the lower portion 22 side. The shower head 30 is made of a metal such as SUS, and has a plurality of through holes 31 formed therein that connect the separation space 201 and the growth space 202.

[0018] As will be described later, seed substrate 10 is placed in growth space 202. Shower head 30 is placed above seed substrate 10 and is formed so that through-hole 31 includes a position facing surface 10a of seed substrate 10. Therefore, the reaction gas supplied to separation space 201 is supplied through through-hole 31 toward surface 10a of seed substrate 10 from a direction intersecting surface 10a of seed substrate 10 (i.e., a direction approximately perpendicular to surface 10a). Therefore, manufacturing apparatus 1 of this embodiment can be said to have a downflow-type gas supply structure that blows the reaction gas down toward surface 10a of seed substrate 10.

[0019] A cooling unit 40 for cooling the separation space 201 is provided around the separation space 201 in the chamber 20. The cooling unit 40 is configured, for example, so that cooling water 42 circulates through a cooling passage 41. In practice, the cooling unit 40 is formed with a flowing water inlet and a flowing water outlet (not shown), and is configured so that the separation space 201 can be cooled by introducing the cooling water 42 through the flowing water inlet and discharging the cooling water 42 through the flowing water outlet. In this embodiment, as will be described later, silane gas is supplied as a reaction gas to the separation space 201. The cooling unit 40 is controlled so that the temperature of the separation space 201 is kept at 400°C or less so that the silane gas does not decompose in the separation space 201. Although the configuration in which the cooling unit 40 is provided around the separation space 201 has been described here, the cooling unit 40 may also be configured, for example, so that a predetermined space is formed in the side portion 23 of the chamber 20, and the cooling water 42 circulates through this space as a cooling passage 41.

[0020] The chamber 20 is provided with first to third supply pipes 51 to 53 on the separation space 201 side, which supply reactive gases for growing the epitaxial layer 11. In this embodiment, the chamber 20 is cylindrical, and the upper portion 21 is also circular in plan view. The first supply pipe 51 is tubular and provided at approximately the center of the upper portion 21, and the second supply pipe 52 is annular (i.e., framed) and provided to surround the first supply pipe 51. The third supply pipe 53 is annular (i.e., framed) and provided to surround the second supply pipe 52. In this embodiment, an example in which the second supply pipe 52 and the third supply pipe 53 are annular will be described, but the second supply pipe 52 and the third supply pipe 53 may also be polygonal frame-shaped.

[0021] The reactive gas includes, for example, a source gas as a growth gas containing silane (SiH4) gas and propane (C3H8) gas, an etching gas as a growth gas containing hydrogen chloride (HCl) gas, a dopant gas containing ammonia (NH3) gas, and a carrier gas containing hydrogen gas.

[0022] The carrier gas is a gas that is less reactive with silane gas and ammonia gas, and can also be called an inert gas. In other words, the inert gas is a gas that is less reactive with silane gas than ammonia gas, and is also less reactive with ammonia gas than silane gas. In addition, although hydrogen gas is used as an example of the carrier gas in this embodiment, the carrier gas may also be argon (Ar) gas or helium (He) gas. In this embodiment, ammonia gas corresponds to an ammonia-based gas, hydrogen chloride gas corresponds to a chlorine-based gas, and silane gas corresponds to a silane-based gas.

[0023] In this embodiment, a dopant gas (i.e., ammonia gas) is supplied from the first supply pipe 51. A source gas (i.e., silane gas and propane gas) and an etching gas (i.e., hydrogen chloride gas) are supplied from the third supply pipe 53. A carrier gas (i.e., hydrogen gas) is supplied from the first to third supply pipes 51 to 53. That is, in this embodiment, in the axial direction of the chamber 20 (hereinafter simply referred to as the axial direction), the second supply pipe 52, through which hydrogen gas that does not easily react with ammonia gas and hydrogen chloride gas is supplied, is disposed between the first supply pipe 51, through which ammonia gas is supplied, and the third supply pipe 53, through which hydrogen chloride gas is supplied. Note that the axial direction of the chamber 20 can also be referred to as the direction normal to the surface direction of the upper portion 21, or as viewed from the direction normal to the surface direction of the upper portion 21. In this embodiment, the first supply pipe 51 corresponds to a dopant gas supply pipe, the second supply pipe 52 corresponds to an inert gas supply pipe, and the third supply pipe 53 corresponds to a growth gas supply pipe.

[0024] The reaction gas is supplied from the first to third supply pipes 51 to 53 to the separation space 201 and then supplied to the growth space 202 through the through-hole 31. At this time, the second supply pipe 52 is disposed between the first supply pipe 51 and the third supply pipe 53 in the axial direction. Therefore, in the separation space 201, the hydrogen gas supplied from the second supply pipe 52 is present between the ammonia gas supplied from the first supply pipe 51 and the hydrogen chloride gas supplied from the third supply pipe 53. Therefore, it can be said that the second supply pipe 52 is disposed so as to supply an inert gas between the portion of the separation space 201 to which the ammonia gas is supplied and the portion to which the hydrogen chloride gas is supplied. In the separation space 201, the hydrogen gas is present between the ammonia gas and the hydrogen chloride gas, so that the reaction between the ammonia gas and the hydrogen chloride gas can be suppressed without disposing a partition wall or the like in the separation space 201. Furthermore, the gases supplied from the separation space 201 to the growth space 202 through the through holes 31 have a smaller difference in flow rate in the radial direction relative to the axial direction of the chamber 20 compared to when the second supply pipe 52 is not provided, because the carrier gas is also supplied from the second supply pipe 52. Therefore, convection in the gases supplied from the through holes 31 can be suppressed.

[0025] A rotation device 60 on which the seed substrate 10 is placed is disposed on the lower side of the chamber 20. In this embodiment, the seed substrate 10 is placed on a susceptor 70 disposed on the rotation device 60.

[0026] The rotating device 60 includes a cylindrical portion 61, a rotating shaft 62, and a driving portion 63. The cylindrical portion 61 is a bottomed cylindrical member that defines a hollow chamber 61a, and a susceptor 70 is disposed at the end of the open end. The open end of the cylindrical portion 61 is disposed so that it faces the upper side of the chamber 20 (i.e., the upper portion 21 side).

[0027] The rotating shaft 62 is a shaft that rotates by the output of the driving unit 63, and is connected to the cylindrical portion 61 so as to be rotatable integrally with the cylindrical portion 61. The driving unit 63 is composed of a motor or the like that outputs a rotational force, and rotates the rotating shaft 62. In the rotation device 60 configured in this manner, the rotating shaft 62 rotates by the output of the driving unit 63, and the cylindrical portion 61 and the susceptor 70 rotate integrally.

[0028] The susceptor 70 has an outer shape that matches the open end of the cylindrical portion 61, and is disposed at the open end of the cylindrical portion 61 to substantially close the cylindrical portion 61. As a result, the hollow chamber 61a of the cylindrical portion 61 is substantially closed.

[0029] Specifically, the susceptor 70 is plate-shaped and has one surface 70a and another surface 70b, and a recess 71 for accommodating the seed substrate 10 is formed in the center of the one surface 70a. The susceptor 70 also has a stepped portion 72 formed on the outer edge of the other surface 70b to be fitted into the open end of the cylindrical portion 61. The susceptor 70 is placed in the cylindrical portion 61 by fitting the stepped portion 72 into the open end of the cylindrical portion 61.

[0030] Seed substrate 10 is placed on susceptor 70 with bottom surface 71a of recess 71 in susceptor 70 serving as a placement surface, and back surface 10b facing bottom surface 71a.

[0031] A heater 80 is disposed in hollow chamber 61a as a heating device for heating seed substrate 10 (i.e., reaction chamber 200). Heater 80 is, for example, a resistance heater made of carbon, and although not shown, is connected to a control unit or the like to heat to a predetermined temperature.

[0032] Furthermore, an exhaust pipe 90 for exhausting reacted gases and unreacted gases is provided on the lower side of the chamber 20. The exhaust pipe 90 is connected to a vacuum pump (not shown) on the side opposite to the chamber 20 side, thereby maintaining the reaction chamber 200 at a predetermined pressure.

[0033] Although not specifically shown, an elevator device is disposed in the hollow chamber 61a to assist a transfer robot in carrying the susceptor 70, on which the seed substrate 10 is placed, into the reaction chamber 200 and in carrying the susceptor 70 out of the reaction chamber 200. For example, this elevator device has a function of raising the susceptor 70 and separating it from the cylindrical portion 61 when carrying out the susceptor 70, thereby handing over the susceptor 70 to the transfer robot. However, the manufacturing apparatus 1 may not necessarily carry in and out the susceptor 70 on which the seed substrate 10 is placed, but may carry in and out only the seed substrate 10 without moving the susceptor 70.

[0034] The above is the configuration of manufacturing apparatus 1 in this embodiment. Next, a method for growing epitaxial layer 11 on surface 10a of seed substrate 10 using manufacturing apparatus 1 will be described.

[0035] First, in the manufacturing apparatus 1 as described above, the susceptor 70 on which the seed substrate 10 is placed is rotated by the rotation device 60 at, for example, 200 rpm, while the heater 80 is driven to heat the growth space 202 to approximately 1600 to 1750°C. In addition, the cooling unit 40 is driven to keep the temperature of the separation space 201 at 400°C or lower.

[0036] Then, by supplying reactive gases from the first to third supply pipes 51 to 53 toward the separation space 201, each gas is supplied from each through-hole 31 of the shower head 30 to the growth space 202. For example, the flow rate of ammonia gas supplied from the first supply pipe 51 is set to 30 sccm. The flow rate of silane gas supplied from the third supply pipe 53 is set to 500 sccm, the flow rate of propane gas is set to 150 sccm, and the flow rate of hydrogen chloride gas is set to 5000 sccm. The total flow rate of hydrogen gas supplied from the first to third supply pipes 51 to 53 is set to 100 slm.

[0037] In the growth space 202, the silane gas and the propane gas react with each other while ammonia gas is introduced, and an epitaxial layer 11 made of n-type SiC grows on the seed substrate 10, thereby producing a SiC wafer 12.

[0038] At this time, since separation space 201 is cooled to 400°C or less by cooling unit 40, it is possible to prevent silane gas from being decomposed into solid silicon in separation space 201. This makes it possible to prevent through-hole 31 of showerhead 30 from becoming clogged.

[0039] Furthermore, because the separation space 201 is cooled to 400°C or less by the cooling unit 40, there is a possibility that ammonia gas and silane gas will react in the separation space 201 to produce solid ammonium chloride. However, in this embodiment, because the second supply pipe 52 is disposed axially between the first supply pipe 51 and the third supply pipe 53 as described above, hydrogen gas exists between the ammonia gas and the hydrogen chloride gas in the separation space 201. Therefore, in the separation space 201, reaction between the ammonia gas and the hydrogen chloride gas can be suppressed without disposing a partition wall or the like in the separation space 201, and clogging of the through holes 31 of the showerhead 30 can be suppressed. Therefore, in this embodiment, clogging of the through holes 31 can be suppressed without disposing a partition wall or the like that separates the separation space 201 into multiple spaces, and the configuration of the showerhead 30 can be simplified.

[0040] Furthermore, the difference in flow rate between the axial direction and the radial direction of the chamber 20 is smaller for each gas supplied from the separation space 201 to the growth space 202 through the through-holes 31 than when the second supply pipe 52 is not provided, because the carrier gas is also supplied from the second supply pipe 52. Therefore, the occurrence of convection in the gas supplied from the through-holes 31 can be suppressed.

[0041] As described above, in this embodiment, the separation space 201 is cooled to 400°C or less by the cooling section 40, which prevents the silane gas from decomposing in the separation space 201 to produce solid silicon, and prevents the through holes 31 of the shower head 30 from becoming clogged.

[0042] Furthermore, second supply pipe 52 is arranged to supply inert gas between a portion of separation space 201 to which ammonia gas is supplied and a portion of separation space 201 to which hydrogen chloride gas is supplied. Therefore, in separation space 201, reaction between ammonia gas and hydrogen chloride gas can be suppressed without providing a partition wall or the like in separation space 201, and clogging of through hole 31 of showerhead 30 can be suppressed.

[0043] Furthermore, the difference in flow rate between the axial direction and the radial direction of the chamber 20 is smaller for each gas supplied from the separation space 201 to the growth space 202 through the through-holes 31 than when the second supply pipe 52 is not provided, because the carrier gas is also supplied from the second supply pipe 52. Therefore, the occurrence of convection in the gas supplied from the through-holes 31 can be suppressed.

[0044] (1) In this embodiment, the second supply pipe 52 is disposed axially between the first supply pipe 51 and the third supply pipe 53. This makes it easier to supply an inert gas between the portion of the separation space 201 to which ammonia gas is supplied and the portion to which hydrogen chloride gas is supplied, and further makes it possible to suppress the reaction between the ammonia gas and the hydrogen chloride gas.

[0045] (Second embodiment) A second embodiment will be described. In this embodiment, convex portions are formed on the shower head 30 in comparison with the first embodiment. As the rest of the configuration is the same as the first embodiment, a description thereof will be omitted here.

[0046] 3, the shower head 30 of this embodiment is provided with a convex portion 32 that protrudes toward the separation space 201 at a portion facing the second supply pipe 52. In other words, the shower head 30 is formed with the convex portion 32 that narrows the flow path of the carrier gas supplied from the second supply pipe 52 to the separation space 201.

[0047] According to the present embodiment described above, the second supply pipe 52 for supplying an inert gas is disposed between the portion of the separation space 201 to which ammonia gas is supplied and the portion to which hydrogen chloride gas is supplied, thereby achieving the same effects as those of the first embodiment.

[0048] (1) In this embodiment, the shower head 30 has a protrusion 32 that protrudes toward the separation space 201 at a portion facing the second supply pipe 52. Therefore, the flow rate of the hydrogen gas (i.e., carrier gas) supplied from the second supply pipe 52 increases when it flows from the portion of the separation space 201 above the protrusion 32 toward the connection portion with the first supply pipe 51 and the connection portion with the third supply pipe 53. This prevents the ammonia gas supplied from the first supply pipe 51 from flowing toward the third supply pipe 53 through the portion above the protrusion 32, and also prevents the hydrogen chloride gas supplied from the third supply pipe 53 from flowing toward the first supply pipe 51 through the portion above the protrusion 32. This further prevents the ammonia gas and the silane gas from reacting with each other in the separation space 201.

[0049] (Third embodiment) A third embodiment will be described. This embodiment is different from the first embodiment in that the configurations of the second and third supply pipes 52, 53 are changed. As the rest of the configuration is the same as the first embodiment, a description thereof will be omitted here.

[0050] 4, the second supply pipe 52 and the third supply pipe 53 of this embodiment are configured to be separated in the circumferential direction with respect to the axial direction, as compared to the first embodiment. In other words, a plurality of second supply pipes 52 and a plurality of third supply pipes 53 are provided concentrically. Note that, although the second supply pipe 52 and the third supply pipe 53 are each cylindrical in this embodiment, they may each be polygonal prism-shaped, or may be a mixture of cylindrical and polygonal prism-shaped.

[0051] According to the present embodiment described above, the second supply pipe 52 for supplying an inert gas is disposed between the portion of the separation space 201 to which ammonia gas is supplied and the portion to which hydrogen chloride gas is supplied, thereby achieving the same effects as those of the first embodiment.

[0052] (1) In this embodiment, the second supply pipes 52 and the third supply pipes 53 are each provided in a concentric manner. Therefore, compared to when the second supply pipes 52 and the third supply pipes 53 are provided in an annular frame shape, the supply pipes 51 to 53 can be processed more easily.

[0053] (Fourth embodiment) A fourth embodiment will be described. This embodiment is different from the third embodiment in that the locations of the first to third supply pipes 51 to 53 are changed. As the rest of the configuration is the same as the third embodiment, a description thereof will be omitted here.

[0054] As shown in Figures 5 and 6, the first to third supply pipes 51 to 53 of this embodiment are arranged so as to be scattered in the axial direction. However, the first to third supply pipes 51 to 53 are arranged concentrically in the axial direction, and the second supply pipe 52 is arranged so as to be located between the first supply pipe 51 and the third supply pipe 53. In this embodiment, the second supply pipe 52 is arranged in approximately the center of the upper part 21, and the first to third supply pipes 51 to 53 are arranged concentrically so as to surround the second supply pipe 52. Note that Figure 5 is a cross-sectional view taken along line VV in Figure 6.

[0055] According to the present embodiment described above, the second supply pipe 52 for supplying an inert gas is disposed between the portion of the separation space 201 to which ammonia gas is supplied and the portion to which hydrogen chloride gas is supplied, thereby achieving the same effects as those of the first embodiment.

[0056] (1) In this embodiment, first to third supply pipes 51 to 53 are arranged in a scattered manner. This allows the growth gas and dopant gas to be supplied more uniformly onto seed substrate 10, thereby improving the quality of epitaxial layer 11.

[0057] (Fifth embodiment) A fifth embodiment will be described. This embodiment is different from the fourth embodiment in that the locations of the first to third supply pipes 51 to 53 are changed. As the rest of the configuration is the same as the fourth embodiment, a description thereof will be omitted here.

[0058] 7 and 8, the first to third supply pipes 51 to 53 of this embodiment are scattered along a first direction in the planar direction of the upper portion 21 and a second direction intersecting the first direction. The first to third supply pipes 51 to 53 are arranged such that the second supply pipe 52 is located between the first supply pipe 51 and the third supply pipe 53 in the axial direction. In this embodiment, the third supply pipe 53 is arranged so as to be located in approximately the center of the upper portion 21. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 8.

[0059] According to the present embodiment described above, the second supply pipe 52 for supplying an inert gas is disposed between the portion of the separation space 201 to which ammonia gas is supplied and the portion to which hydrogen chloride gas is supplied, thereby achieving the same effects as those of the first embodiment.

[0060] (1) Even if the first to third supply pipes 51 to 53 are scattered along the first and second directions as in this embodiment, the same effect as in the fourth embodiment can be obtained as long as the second supply pipe 52 is positioned between the first supply pipe 51 and the third supply pipe 53 in the axial direction.

[0061] (Sixth embodiment) The sixth embodiment will be described. This embodiment is a combination of the second and fourth embodiments. As the rest of the configuration is the same as the second and fourth embodiments, a description thereof will be omitted here.

[0062] 9, a convex portion 32 is provided on a portion of the shower head 30 that faces the second supply pipe 52. The first to third supply pipes 51 to 53 are arranged in a scattered manner, but compared to the second embodiment, their locations have been appropriately changed to make it easier to provide the convex portions 32. However, the first to third supply pipes 51 to 53 are arranged such that the second supply pipe 52 is located between the first supply pipe 51 and the third supply pipe 53 in the axial direction.

[0063] According to the present embodiment described above, the second supply pipe 52 for supplying an inert gas is disposed between the portion of the separation space 201 to which ammonia gas is supplied and the portion to which hydrogen chloride gas is supplied, thereby achieving the same effects as those of the second and fourth embodiments.

[0064] (Other embodiments) Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0065] For example, in each of the above embodiments, the growth gas may be a gas containing silane trichloride gas. In this case, hydrogen chloride gas may not be contained. In such a configuration, the silane trichloride gas corresponds to the silane-based gas and the chlorine-based gas.

[0066] Furthermore, in each of the above-described embodiments, a plurality of third supply pipes 53 may be provided, and silane gas and hydrogen chloride gas may be supplied from separate supply pipes. In this case, for example, in the above-described third embodiment, silane gas may be supplied from some of the plurality of third supply pipes 53, and hydrogen chloride gas may be supplied from the remainder.

[0067] In each of the above embodiments, it is sufficient that hydrogen gas (ie, inert gas) is supplied from at least the second supply pipe 52.

[0068] In the third to sixth embodiments, the locations of the first to third supply pipes 51 to 53 can be changed as appropriate.

[0069] The above embodiments may be combined. For example, the second embodiment may be combined with the third or fifth embodiment to provide the shower head 30 with the convex portion 32.

[0070] (Features of the present invention)

[0071] [Claim 1] A silicon carbide wafer manufacturing apparatus, a cylindrical chamber (20) having an upper portion (21) and a lower portion (22) that constitutes a reaction chamber (200) into which a reaction gas is supplied and in which an epitaxial layer (11) made of silicon carbide is grown on a surface (10a) side of a seed substrate (10) made of silicon carbide; a susceptor (70) disposed at a lower side within the chamber and on which the seed substrate is placed; a supply pipe (51-53) connected to the upper part of the chamber and supplying the reaction gas to the reaction chamber; a shower head (30) disposed so as to partition the reaction chamber into a growth space (202) on the lower side and a separation space (201) on the upper side, and having a plurality of through holes (31) formed therein for communicating the growth space with the separation space; a cooling section (40) that cools the separation space, the cooling unit is capable of cooling the separation space to 400°C or less, The supply pipes include a dopant gas supply pipe (51) to which an ammonia-based gas contained in the reaction gas is supplied, a growth gas supply pipe (53) to which a growth gas containing a silane-based gas and a chlorine-based gas contained in the reaction gas is supplied, and an inert gas supply pipe (52) to supply an inert gas contained in the reaction gas between a portion of the separation space to which the ammonia-based gas is supplied and a portion of the separation space to which the chlorine-based gas is supplied.

[0072] [Claim 2] 2. The silicon carbide wafer manufacturing apparatus according to claim 1, wherein the dopant gas supply pipe, the growth gas supply pipe, and the inert gas supply pipe are arranged such that the inert gas supply pipe is located between the dopant gas supply pipe and the growth gas supply pipe in an axial direction of the chamber.

[0073] [Claim 3] 3. The silicon carbide wafer manufacturing apparatus according to claim 1, wherein the shower head is provided with a protrusion (32) that protrudes toward the separation space at a position opposite the inert gas supply pipe.

[0074] [Claim 4] 4. The silicon carbide wafer manufacturing apparatus according to claim 1, wherein one of the dopant gas supply pipe and the growth gas supply pipe is cylindrical, the inert gas supply pipe is cylindrical and surrounds the dopant gas supply pipe, and the other of the dopant gas supply pipe and the growth gas supply pipe is cylindrical and surrounds the inert gas supply pipe.

[0075] [Claim 5] 4. The silicon carbide wafer manufacturing apparatus according to claim 1, wherein the dopant gas supply pipe, the growth gas supply pipe, and the inert gas supply pipe are each cylindrical and are arranged in a scattered manner.

[0076] [Claim 6] 6. The silicon carbide wafer manufacturing apparatus according to claim 5, wherein the dopant gas supply pipe, the growth gas supply pipe, and the inert gas supply pipe are arranged concentrically and scatteredly.

[0077] [Claim 7] 6. The silicon carbide wafer manufacturing apparatus according to claim 5, wherein the dopant gas supply pipe, the growth gas supply pipe, and the inert gas supply pipe are scattered along a first direction in one direction of the surface direction of the upper portion and a second direction intersecting the first direction. [Explanation of symbols]

[0078] 10 types of substrates 10a surface 11 Epitaxial layer 20 Chamber 21 Upper 22 Lower 30 shower head 31 Through hole 40 Cooling section 51 First supply pipe (dopant gas supply pipe) 52 Second supply pipe (inert gas supply pipe) 53 Third supply pipe (growth gas supply pipe) 70 Susceptor 200 reaction chamber 201 Separated space 202 Growth space

Claims

1. A silicon carbide wafer manufacturing apparatus, a cylindrical chamber (20) having an upper portion (21) and a lower portion (22) that constitutes a reaction chamber (200) into which a reaction gas is supplied and in which an epitaxial layer (11) made of silicon carbide is grown on a surface (10a) side of a seed substrate (10) made of silicon carbide; a susceptor (70) disposed at a lower side in the chamber and on which the seed substrate is placed; supply pipes (51-53) connected to the upper portion of the chamber for supplying the reaction gas to the reaction chamber; a shower head (30) disposed so as to partition the reaction chamber into a growth space (202) on the lower side and a separation space (201) on the upper side, and having a plurality of through holes (31) formed therein for communicating the growth space with the separation space; a cooling unit (40) that cools the separation space, the cooling unit is capable of cooling the separation space to 400°C or less, The supply pipes include a dopant gas supply pipe (51) to which an ammonia-based gas contained in the reaction gas is supplied, a growth gas supply pipe (53) to which a growth gas containing a silane-based gas and a chlorine-based gas contained in the reaction gas is supplied, and an inert gas supply pipe (52) to supply an inert gas contained in the reaction gas between a portion of the separation space to which the ammonia-based gas is supplied and a portion of the separation space to which the chlorine-based gas is supplied.

2. 2. The silicon carbide wafer manufacturing apparatus according to claim 1, wherein the dopant gas supply pipe, the growth gas supply pipe, and the inert gas supply pipe are arranged such that the inert gas supply pipe is located between the dopant gas supply pipe and the growth gas supply pipe in an axial direction of the chamber.

3. 2. The silicon carbide wafer manufacturing apparatus according to claim 1, wherein the shower head is provided with a convex portion (32) that protrudes toward the separation space at a position opposite the inert gas supply pipe.

4. 4. The silicon carbide wafer manufacturing apparatus according to claim 1, wherein one of the dopant gas supply pipe and the growth gas supply pipe is cylindrical, the inert gas supply pipe is cylindrical and surrounds the dopant gas supply pipe, and the other of the dopant gas supply pipe and the growth gas supply pipe is cylindrical and surrounds the inert gas supply pipe.

5. 4. The silicon carbide wafer manufacturing apparatus according to claim 1, wherein the dopant gas supply pipe, the growth gas supply pipe, and the inert gas supply pipe are each cylindrical and are arranged in a scattered manner.

6. 6. The silicon carbide wafer manufacturing apparatus according to claim 5, wherein the dopant gas supply pipe, the growth gas supply pipe, and the inert gas supply pipe are arranged concentrically and scatteredly.

7. 6. The silicon carbide wafer manufacturing apparatus according to claim 5, wherein the dopant gas supply pipe, the growth gas supply pipe, and the inert gas supply pipe are scattered along a first direction in one direction of a surface direction of the upper portion and a second direction intersecting the first direction.

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