SiC SINGLE CRYSTAL MANUFACTURING DEVICE AND METHOD OF MANUFACTURING SiC SINGLE CRYSTAL

Abstract

To provide an SiC single crystal manufacturing device and a method of manufacturing an SiC single crystal that are high in use efficiency and energy efficiency.SOLUTION: There is provided an SiC single crystal manufacturing device that comprises a continuous furnace having an entrance, an exit, and a heating region provided between the entrance and the exit, wherein the continuous furnace is provided internally with crucibles which have filled parts filled with SiC solid raw material below it, a support member which is mounted with the crucibles, and carries the crucibles one after another from the entrance toward the exit, and a lower heating heater which is provided along the carrying path of the crucibles and heats the filled parts of the crucibles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an SiC single crystal manufacturing apparatus and a SiC single crystal manufacturing method. [Background technology]

[0002] SiC (silicon carbide) has excellent semiconductor properties and is attracting attention as a semiconductor material for power devices and other applications.

[0003] Since SiC exhibits the characteristic of sublimating at temperatures above 2000°C, SiC single crystals are generally produced by a vapor phase growth-based method known as the modified Lely method.

[0004] In the modified Lely process, a solid SiC source is heated to a temperature exceeding 2000°C, and the sublimated gas generated by decomposition from the solid source is transported by diffusion to the vicinity of a seed crystal that has been placed in advance at a relatively low temperature. The increased degree of supersaturation is used as the driving force for recrystallization on the seed crystal, thereby growing a SiC single crystal.

[0005] Furthermore, in recent years, advances in simulation technology have made it possible to optimize the growth environment of single crystals, including residual stress and temperature distribution within the single crystal. As a result, it has become possible to use the modified Lely method to obtain large-diameter single crystals while preventing the occurrence of microcracks and dislocations.

[0006] Patent Document 1 describes a method and apparatus for producing SiC single crystals using a heating method that does not rely on self-heating of the graphite crucible, in which an external chamber including the crucible is evacuated, and then an induction coil is energized to inductively heat a heater, and the crucible is heated by the radiant heat generated thereby. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-290885 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the manufacturing apparatus described in Patent Document 1 is configured such that the crucible is surrounded by components such as heat insulating materials, and if the heat capacity of the apparatus is increased by increasing the amount of heat insulating materials, it takes time to heat up and cool down, and the operating time of the entire apparatus becomes longer, resulting in a problem of low utilization efficiency (time efficiency) of the apparatus. Furthermore, reducing the amount of insulation and decreasing the heat capacity can shorten the time it takes to heat up and cool down, improving utilization efficiency. However, the reduced insulation increases the amount of energy required to maintain the heating temperature, resulting in a problem of reduced energy efficiency.

[0009] The present invention has been made to solve the above-mentioned problems, and has an object to provide a SiC single crystal manufacturing apparatus and a SiC single crystal manufacturing method that have high utilization efficiency and energy efficiency. [Means for solving the problem]

[0010] The SiC single crystal manufacturing apparatus of the present invention comprises a continuous furnace having an inlet, an outlet, and a heating region provided between the inlet and the outlet, wherein the continuous furnace is provided with a crucible having a filling section at its lower part for filling with a SiC solid raw material, a support member on which the crucible is placed and which transports the crucible sequentially from the inlet to the outlet, and a lower heater provided along the transport path of the crucible and which heats the filling section of the crucible.

[0011] Since the SiC single crystal manufacturing apparatus of the present invention is equipped with a continuous furnace, there is no need to lower the temperature inside the furnace in order to replace the crucible that is the object to be heated, and most of the time during operation of the apparatus can be devoted to heating the crucible, i.e., to forming a single crystal film, resulting in high utilization efficiency and energy efficiency of the apparatus.

[0012] In the SiC single crystal manufacturing apparatus of the present invention, an upper heater is preferably provided above the lower heater. If an upper heater is provided above the lower heater, the upper part of the crucible can be heated to adjust the temperature. Since a SiC seed crystal is placed in the upper part of the crucible, the temperature of the filling section where the SiC solid raw material is placed and the temperature of the seed crystal placement section where the seed crystal is placed can be controlled separately. As a result, an appropriate temperature gradient can be formed between the filling section and the seed crystal placement section, allowing for the production of high-quality SiC single crystals with few defects and distortion.

[0013] In the SiC single crystal manufacturing apparatus of the present invention, a shielding member is preferably provided above the lower heater. When a shielding member is provided above the lower heater, the heat from the lower heater can be prevented from reaching the top of the crucible, thereby forming a temperature gradient between the filling section and the seed crystal placement section where the seed crystal is placed, and a high-quality SiC single crystal with few defects and distortion can be obtained.

[0014] In the SiC single crystal manufacturing apparatus of the present invention, a flange portion that protrudes outward from the side surface of the crucible is preferably provided on the side surface of the crucible at a position above the filling portion of the crucible. The flange prevents heat from the lower heater from reaching the upper part of the crucible, and because a SiC seed crystal is placed in the upper part of the crucible, a temperature gradient can be created between the filling part and the seed crystal placement part, enabling the production of high-quality SiC single crystals with few defects and distortions.

[0015] In the SiC single crystal manufacturing apparatus of the present invention, the flange portion preferably has an annular shape. When the flange portion has a circular ring shape, the heat shielding effect of the flange portion on the side surface of the crucible is uniform even when the crucible is rotated.

[0016] In the SiC single crystal manufacturing apparatus of the present invention, it is preferable that the heights of the flange portions of two crucibles adjacent to each other in the direction of crucible transfer are different. If the heights of the flange portions of two crucibles adjacent to each other in the direction of crucible transport are different, contact between the flange portions can be prevented even when the crucibles are close to each other.

[0017] In the SiC single crystal manufacturing apparatus of the present invention, it is preferable that the heights of the mounting surfaces on which the crucible is mounted of two of the support members adjacent to each other in the direction in which the crucible is transported are different. When the heights of the mounting surfaces of two support members adjacent in the transport direction are different, contact between the flange portions can be prevented even if the heights of the flange portions of two crucibles adjacent in the transport direction are the same.

[0018] In the SiC single crystal manufacturing apparatus of the present invention, it is preferable that the surface of the support member on which the crucible is placed is inclined at a predetermined angle with respect to the direction in which the crucible is transported. When the support surface on which the crucible of the support member is placed is inclined at a predetermined angle with respect to the conveying direction of the crucible, contact between the flange portions of two adjacent crucibles in the conveying direction can be prevented even if the flange portions are the same height.

[0019] In the SiC single crystal manufacturing apparatus of the present invention, the support member preferably includes a rotation mechanism for rotating the crucible. If the support member is equipped with a rotation mechanism for rotating the crucible, the crucible can be uniformly heated by the lower heater. In this case, the temperature distribution inside the crucible is homogenized, resulting in SiC single crystals with few defects and distortion.

[0020] In the SiC single crystal manufacturing apparatus of the present invention, the continuous furnace is equipped with a pressure reduction mechanism for reducing the pressure inside, and further includes a pressure reduction chamber connected to the inlet of the continuous furnace and a pressure recovery chamber connected to the outlet of the continuous furnace, and it is preferable that airtight doors are provided between the continuous furnace and the pressure reduction chamber, and between the continuous furnace and the pressure recovery chamber. If the continuous furnace is provided with a pressure reducing mechanism for reducing the pressure inside, it becomes easy to reduce the pressure inside the continuous furnace. Furthermore, by heating the SiC solid source material in a reduced pressure environment, sublimation of the SiC solid source material is promoted, enabling efficient production of SiC single crystals.

[0021] In the SiC single crystal manufacturing apparatus of the present invention, it is preferable that a pre-processing storage section for storing the crucible before heating is provided upstream of the inlet of the continuous furnace, and a post-processing storage section for storing the crucible after heating is provided downstream of the outlet of the continuous furnace. If a pre-treatment storage section is provided upstream of the inlet of the continuous furnace, the crucibles can be stored before treatment. Also, if a post-treatment storage section is provided downstream of the outlet of the continuous furnace, the crucibles can be stored after treatment.

[0022] The method for producing a SiC single crystal of the present invention is characterized by using the SiC single crystal production apparatus of the present invention. The method for producing a SiC single crystal of the present invention uses the SiC single crystal production apparatus of the present invention, and therefore can produce a SiC single crystal efficiently. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view schematically showing an example of an SiC single crystal manufacturing apparatus according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the SiC single crystal manufacturing apparatus shown in FIG. 1, viewed from a direction perpendicular to the direction of conveyance of the crucible. [Figure 3] FIG. 3 is a top view of the SiC single crystal manufacturing apparatus shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the SiC single crystal manufacturing apparatus shown in FIG. 1 as seen from the front in the direction of crucible transfer. [Figure 5] FIG. 5 is a perspective view schematically showing an example of an SiC single crystal manufacturing apparatus according to the second embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view of the SiC single crystal manufacturing apparatus shown in FIG. 5, viewed from the front in the direction of conveyance of the crucible. [Figure 7] FIG. 7 is a partially enlarged top view of the SiC single crystal manufacturing apparatus shown in FIG. [Figure 8] FIG. 8 is a perspective view schematically showing an example of an SiC single crystal manufacturing apparatus according to the third embodiment of the present invention. [Figure 9] FIG. 9 is a cross-sectional view of the SiC single crystal manufacturing apparatus shown in FIG. 8, viewed from the front in the direction of crucible transfer. [Figure 10] FIG. 10 is a top view of the SiC single crystal manufacturing apparatus shown in FIG. [Figure 11] FIG. 11 is a partial cross-sectional view of the SiC single crystal manufacturing apparatus shown in FIG. 8, viewed from the side in the conveying direction. [Figure 12] FIG. 12 is a partial cross-sectional view schematically showing a modified example of the SiC single crystal manufacturing apparatus according to the third embodiment of the present invention. [Figure 13] FIG. 13 is a partial cross-sectional view schematically showing another modified example of the SiC single crystal manufacturing apparatus according to the third embodiment of the present invention. [Figure 14] FIG. 14 is a diagram schematically showing the arrangement of crucibles when the SiC single crystal manufacturing apparatus shown in FIG. 12 or 13 is viewed from above. [Figure 15] FIG. 15 is a cross-sectional view of an example of an SiC single crystal manufacturing apparatus according to the fourth embodiment of the present invention, viewed from the front in the transfer direction. [Figure 16] FIG. 16 is a top view schematically showing an example of an SiC single crystal manufacturing apparatus according to the fifth embodiment of the present invention. [Figure 17] FIG. 17 is a top view schematically showing an example of an SiC single crystal manufacturing apparatus according to the sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be appropriately modified and applied within the scope of the present invention.

[0025] [SiC single crystal manufacturing equipment] The SiC single crystal manufacturing apparatus of the present invention comprises a continuous furnace having an inlet, an outlet, and a heating region provided between the inlet and the outlet, wherein the continuous furnace is provided with a crucible having a filling section at its lower part for filling with a SiC solid raw material, a support member on which the crucible is placed and which transports the crucible sequentially from the inlet to the outlet, and a lower heater provided along the transport path of the crucible and which heats the filling section of the crucible.

[0026] FIG. 1 is a perspective view schematically showing an example of an SiC single crystal manufacturing apparatus according to a first embodiment of the present invention. 1 includes a continuous furnace 101. In the continuous furnace 101, a crucible 40, a support member 50, and a lower heater 60 are provided.

[0027] Fig. 2 is a cross-sectional view of the SiC single crystal manufacturing apparatus shown in Fig. 1, seen from a direction perpendicular to the direction of conveyance of the crucible. Fig. 3 is a top view of the SiC single crystal manufacturing apparatus shown in Fig. 1. As shown in FIGS. 2 and 3, the continuous furnace 101 is configured with a housing 10 and has an inlet 11, an outlet 13, and a heating region 30 provided between the inlet 11 and the outlet 13. The heating region 30 is also the region where the lower heater 60 is arranged.

[0028] 2, in continuous furnace 101, crucible 40 is placed on support member 50, which sequentially transports crucible 40 from inlet 11 toward outlet 13. The direction in which crucible 40 is transported is indicated by a thick arrow. That is, the direction in which crucible 40 is transported is also the direction indicated by arrow X in FIG. 2 (hereinafter referred to as transport direction X).

[0029] As shown in Fig. 3, the lower heater 60 is provided along the transport path of the crucible 40. The transport path of the crucible 40 is a predetermined area defined by the path (trajectory) along which the crucible 40 is transported. In Fig. 3, the lower heater 60 has a predetermined length (width) in a direction perpendicular to the transport direction X (the direction indicated by the arrow Y in Fig. 2, hereinafter also referred to as the width direction Y), and extends in the transport direction X. The lower heater 60 extends in the transport direction X in the same manner as the transport path, and is provided at a position spaced a certain distance from the transport path in the width direction Y, approximately parallel to the transport path. The lower heater 60 is provided at both ends of the transport path in the width direction Y (both on the -Y direction side and the +Y direction side). However, the lower heater 60 may be provided on only one side of the transport path of the crucible 40 in the width direction Y (either the −Y side or the +Y side).

[0030] The heating region 30 refers to a region of the continuous furnace 101 other than the inlet 11 and the outlet 13 where the lower heater 60 is disposed. The heating zone may be arranged over the entire area of ​​the continuous furnace in the conveying direction X, or may be arranged only in a part of the area. In the SiC single crystal manufacturing apparatus 1 shown in FIGS. 2 and 3, only a part of the conveying direction X of the continuous furnace 101 is the heating region 30.

[0031] FIG. 4 is a cross-sectional view of the SiC single crystal manufacturing apparatus shown in FIG. 1 as seen from the front in the direction of crucible transfer. As shown in FIG. 4, a heat insulating material 15 is provided inside the housing 10, but is omitted in FIGS. 4, crucible 40 extends in a direction perpendicular to transport direction X and width direction Y (the direction indicated by arrow Z in FIG. 2, hereinafter also referred to as height direction Z), has a filling section 41 in which SiC solid raw material 141 is filled at its lower part (downward, −Z direction) and has a seed crystal placement section 43 in which seed crystal 143 is placed at its upper part (upward, +Z direction).

[0032] Lower heater 60 heats filling portion 41 of crucible 40, causing SiC solid source material 141 filled in filling portion 41 to sublimate due to the heat and recrystallize on the surface of seed crystal 143, thereby growing a SiC single crystal. At this time, since only the lower portion of crucible 40 is heated, a temperature gradient in the vertical direction can be efficiently formed in crucible 40.

[0033] The SiC single crystal manufacturing apparatus 1 shown in Figures 1 to 4 is equipped with a continuous furnace 101, so there is no need to lower the temperature inside the entire furnace in order to replace the crucible 40 to be heated, and most of the time during operation of the apparatus can be spent heating the crucible, i.e., forming a single crystal film, resulting in high utilization efficiency and energy efficiency of the apparatus.

[0034] The crucible 40 has a cylindrical space inside, with a lower part of the space serving as a filling section 41 and an upper part of the space serving as a seed crystal placement section 43 . The crucible 40 has a cylindrical outer shape and has the cylindrical space inside, as described above, so that it can be said to have a cylindrical shape as a whole.

[0035] The material constituting the crucible 40 may be any material that can be used at temperatures of 2000° C. or higher, such as carbon, SiC, etc. The surface of the carbon crucible may also be coated with SiC or TaC.

[0036] The height of the crucible is not particularly limited, but is preferably 200 to 1000 mm.

[0037] The cross-sectional area of ​​the crucible is 7000 to 71000 mm 2 It is preferable that: The cross-sectional area of ​​the crucible is the cross-sectional area of ​​the internal space when the crucible is cut at a point half the height of the crucible along a plane perpendicular to the height direction of the crucible. Since the above cross-sectional area of ​​the crucible is essentially the upper limit of the size of the SiC seed crystal, the cross-sectional area of ​​the crucible may be appropriately set depending on the size of the SiC single crystal to be produced.

[0038] When the internal space of the crucible is circular when cut along a plane perpendicular to the height direction of the crucible, the diameter of the circle is also referred to as the inner diameter of the crucible. When the internal space of the crucible has a circular shape, the inner diameter of the crucible is preferably 100 to 300 mm.

[0039] The support member 50 is composed of a flat mounting portion 51 having a mounting surface 51a on which the crucible 40 is placed, and a cylindrical support portion 53 that supports the crucible 40 together with the mounting portion 51. Furthermore, the support portion 53 is provided with a through-hole 53a that penetrates the interior in the length direction (height direction Z) and opens to the mounting surface 51a of the mounting portion 51.

[0040] Because through-hole 53a is open to mounting surface 51a, part of the radiation emitted from the bottom surface of crucible 40 (the surface in contact with mounting surface 51a) reaches the lower part of support member 50 through through-hole 53a. By measuring this radiation with a radiation thermometer, the temperature of crucible 40 can be measured. In addition, multiple radiation thermometers may be provided, and they may be provided outside the housing 10, such as on the top side of the housing 10 so that the top surface of the crucible 40 can be observed, or on the side of the housing 10 so that the side surface of the crucible 40 can be observed.

[0041] The material constituting the support member may be any material that can be used at temperatures of 2000° C. or higher, such as carbon, SiC, etc. The surface of the carbon support member may be coated with SiC or TaC.

[0042] The time required for the support member to transport the crucible from the inlet to the outlet may be 1 to 1000 hours. The conveying speed at which the support member conveys the crucible is, for example, 100 to 10,000 cm / h. The support member may transport the crucible continuously or intermittently, i.e., the crucible may be temporarily not transported in the continuous furnace.

[0043] The lower heater indirectly heats the filling portion of the crucible by generating heat itself, and therefore the lower heater does not directly heat the crucible by induction heating.

[0044] The lower heater may be a resistance heating type heater, or an induction heating type heater in which the heater itself is heated by induction heating.

[0045] The lower heater is disposed along the transfer path of the crucible. The lower heater may be disposed on only one side of the transfer path, but is preferably disposed on both sides of the transfer path as in the SiC single crystal manufacturing apparatus 1 shown in Figures 1 to 4. By disposing the lower heaters on both sides of the transfer path, temperature unevenness in the crucible can be suppressed.

[0046] The shape of the lower heater is not particularly limited as long as it can heat the filling portion of the crucible to 2000° C. or higher. For example, a heater having a rectangular heating region with a predetermined length in the transport direction and a predetermined length (width) in the height direction may be a coil-shaped heater arranged with its main surface facing the transport path, or multiple rod-shaped heaters extending in the height direction may be arranged in the transport direction.

[0047] The lower heater is preferably capable of setting the temperature difference between the filling section and the seed crystal placement section to 10 to 200°C by heating. When the temperature difference (temperature gradient) between the filling section and the seed crystal placement section is within the above range, a high-quality SiC single crystal with few defects and distortion can be obtained. If it is desired to measure the temperatures of the filling section and the seed crystal placement section separately, the radiation emitted from the bottom surface of the crucible and the radiation emitted from the top surface of the crucible can be measured using a radiation thermometer.

[0048] The housing (also referred to as a chamber) of the continuous furnace is preferably made of metal, and a heat insulating material is preferably arranged on the inner surface of the housing. Examples of the heat insulating material include carbon fiber felt and molded bodies.

[0049] The interior of the continuous furnace is preferably substituted with an inert gas, more preferably under reduced pressure, and even more preferably maintained at a vacuum. Examples of the inert gas include N2 gas and Ar gas, with Ar gas being preferred. The pressure inside the continuous furnace is preferably less than 100 Pa, more preferably 10 Pa or less, and even more preferably 1 Pa or less. The oxygen concentration in the continuous furnace is preferably less than 100 ppm.

[0050] (Second embodiment) FIG. 5 is a perspective view schematically showing an example of an SiC single crystal manufacturing apparatus according to the second embodiment of the present invention. As shown in FIG. 5, the SiC single crystal manufacturing apparatus 2 includes a continuous furnace 102 . A crucible 40, a support member 50, a lower heater 60, and an upper heater 70 are provided in the continuous furnace 102.

[0051] FIG. 6 is a cross-sectional view of the SiC single crystal manufacturing apparatus shown in FIG. 5, viewed from the front in the direction of conveyance of the crucible. As shown in FIG. 6, the upper heater 70 is a heater provided above the lower heater 60 (on the positive side in the height direction Z) so as to face the seed crystal placing part 43, and heats the seed crystal placing part 43 of the crucible 40. The provision of upper heater 70 makes it easier to adjust the temperature of seed crystal placement part 43 of crucible 40. Therefore, an appropriate temperature gradient can be formed between filling part 41 and seed crystal placement part 43, and a high-quality SiC single crystal with few defects and distortion can be obtained.

[0052] The crucible 40 is provided with a flange portion 80 . The flange portion 80 is a portion that protrudes outward from the side surface of the crucible 40 at a position on the side surface of the crucible 40 that is above the filling portion 41 and below the seed crystal placement portion 43 . In FIG. 6, flange portion 80 is provided at a position above lower heater 60 and below upper heater 70, sandwiched between lower heater 60 and upper heater 70.

[0053] The provision of flange portion 80 can prevent the heat from lower heater 60 from reaching seed crystal placement portion 43, thereby forming an appropriate temperature gradient between filling portion 41 and seed crystal placement portion 43, and enabling the production of high-quality SiC single crystals with few defects and distortion. Furthermore, when an upper heater 70 is provided, the flange portion 80 can separate the heating regions of the lower heater 60 and the upper heater 70 .

[0054] The shape and heating method of upper heater 70 are not particularly limited as long as it can heat the seed crystal placement portion of the crucible to 2000 to 2400° C., and a heater with the same shape and heating method as lower heater 60 can be used. By using the upper heater 70 to heat the temperature of the seed crystal placement section of the crucible to the above range, a good temperature gradient is achieved between the filling section and the seed crystal placement section, and a high-quality SiC single crystal with few defects and distortion can be obtained.

[0055] FIG. 7 is a partially enlarged top view of the SiC single crystal manufacturing apparatus shown in FIG. 7, flange portion 80 has a circular shape at its portion (inner edge) 80a that contacts crucible 40 and a rectangular shape at its portion (outer edge) 80b that does not contact crucible 40. A flange portion having such a shape is also called a square shape due to the characteristics of its outer shape. When the flange portion has a rectangular shape, gaps are less likely to be formed between adjacent crucibles 40 in the transport direction due to the flange portion 80. Therefore, the heat applied from the lower heater 60 to the seed crystal placement portion 43 can be sufficiently shielded.

[0056] The height at which flange portion 80 is provided may be any height above lower heater 60, and may be any height below upper heater 70 if an upper heater is provided. As long as the above conditions are met, flange portion 80 does not necessarily have to be provided in the center of crucible 40 in the height direction, and its position may vary slightly in the height direction of crucible 40.

[0057] The shape of the flange portion is not limited to the square shape described above. The flange may be formed integrally with the crucible or may be separable from the crucible, which makes it easy to replace the flange depending on its deterioration.

[0058] (Third embodiment) FIG. 8 is a perspective view schematically showing an example of an SiC single crystal manufacturing apparatus according to the third embodiment of the present invention. As shown in FIG. 8, the SiC single crystal manufacturing apparatus 3 includes a continuous furnace 103 . A crucible 40, a support member 50, a lower heater 60, and a shielding member 90 are provided inside the continuous furnace 103. The crucible 40 is provided with a flange portion 81.

[0059] FIG. 9 is a cross-sectional view of the SiC single crystal manufacturing apparatus shown in FIG. 8, viewed from the front in the direction of crucible transfer. As shown in FIG. 9, a shielding member 90 is provided above the lower heater 60. Furthermore, a flange portion 81 is provided on the side surface of the crucible 40 . The flange portion 81 and the shielding member 90 can each block the heat from the lower heater 60 from reaching the seed crystal placement portion 43, thereby forming an appropriate temperature gradient between the filling portion 41 and the seed crystal placement portion 43, and producing a high-quality SiC single crystal with few defects and distortion. Unlike the flange portion 81, the shielding member 90 does not contact the crucible 40. The shielding member 90 is fixed directly or indirectly to the housing 10 that constitutes the continuous furnace 103.

[0060] FIG. 10 is a top view of the SiC single crystal manufacturing apparatus shown in FIG. 10, the arrow above flange portion 81 indicates the direction of rotation of crucible 40. That is, support member 50 (see FIG. 9) is provided with a rotation mechanism that rotates crucible 40 clockwise when viewed from above. If the support member is provided with a rotation mechanism that rotates crucible 40, crucible 40 can be uniformly heated by lower heater 60. In this case, the temperature distribution within crucible 40 is homogenized, making it possible to obtain SiC single crystals with few defects and distortion.

[0061] The speed at which the crucible is rotated by the rotation mechanism is not particularly limited, but is preferably 10 to 0.1 rotations per minute, and the direction of rotation is not particularly limited.

[0062] The shape of flange portion 81 provided on crucible 40, which is rotated by the rotation mechanism, is such that the portion that contacts crucible 40 is circular, and the portion that does not contact crucible 40 is circular. Flange portion 81 of this shape is also referred to as annular due to the characteristics of its outer shape. The shape of the flange portion is not particularly limited, but if flange portion 81 has an annular shape, the heat shielding effect of flange portion 81 becomes uniform when crucible 40 is rotated.

[0063] FIG. 11 is a partial cross-sectional view of the SiC single crystal manufacturing apparatus shown in FIG. 8, viewed from the side in the conveying direction. As shown in FIG. 11, a mounting surface 51a of the support member 50 on which the crucible 40 is mounted is inclined at a predetermined angle θ with respect to the conveying direction X of the crucible 40. As shown in FIG. 11, when the support surface 51a on which the crucible 40 is placed is inclined with respect to the conveying direction X of the crucible 40, even if the heights of the flange portions 81 of two adjacent crucibles 40 in the conveying direction X are the same, the flange portion 81 of the crucible 40 in the +X direction will be positioned higher (+Z direction) than the flange portion 81 of the crucible 40 in the -X direction, thereby preventing the flange portions 81 from coming into contact with each other. The angle θ is not particularly limited as long as it can prevent contact between the flange portions 81, but is preferably, for example, 0.1 to 10°. Furthermore, the placement surface 51a of the support member 50 on which the crucible 40 is placed may be inclined by a predetermined angle −θ in the opposite direction to the transfer direction X of the crucible 40.

[0064] The method of preventing contact between two adjacent flange portions in the conveying direction is not limited to the method of inclining the placement surface described above, and for example, contact between the flange portions can also be prevented by the following method.

[0065] FIG. 12 is a partial cross-sectional view schematically showing a modified example of the SiC single crystal manufacturing apparatus according to the third embodiment of the present invention. In continuous furnace 104 constituting SiC single crystal manufacturing apparatus 4 shown in FIG. 12, flange portions 81 of two crucibles 40 adjacent to each other in conveyance direction X have different heights. 12, the height of the flange portion 81 of each crucible 40 is different from the height of the flange portion 81 of the other crucible 40 adjacent to it in the conveying direction X. For example, when focusing on a crucible 40 having a flange portion 81 with a height h1, the heights of the flange portions 81 of the other two crucibles 40 adjacent to this crucible 40 in the transport direction X are both h2. Therefore, the flange portions 81 do not come into contact with each other.

[0066] FIG. 13 is a partial cross-sectional view schematically showing another modified example of the SiC single crystal manufacturing apparatus according to the third embodiment of the present invention. In continuous furnace 105 constituting SiC single crystal manufacturing apparatus 5 shown in FIG. 13, two support members 50 adjacent to each other in transfer direction X have mounting surfaces 51a on which crucibles 40 are placed at different heights. The plurality of crucibles 40 shown in FIG. 12 all have the same height of the flange portions, but the heights of the support members 50 adjacent to each other in the transport direction X, that is, the heights of the mounting surfaces 51a, are different. Specifically, the heights of the mounting surfaces 51a of two adjacent support members 50 in the transport direction X differ by h3. Therefore, the flange portions 81 of two adjacent crucibles 40 in the transport direction do not come into contact with each other.

[0067] FIG. 14 is a diagram schematically showing the arrangement of crucibles when the SiC single crystal manufacturing apparatus shown in FIG. 12 or 13 is viewed from above. As shown in Figure 14, when the SiC single crystal manufacturing apparatus shown in Figures 12 and 13 is viewed from above, crucibles 40 with flange portions 81 that are relatively high and crucibles 40 with flange portions 81 that are relatively low are arranged alternately in the transport direction X.

[0068] In the above, a method for preventing contact between flange portions has been described using the example of a case where the support member has a rotation mechanism, i.e., a case where the flange portion is annular. However, the above method can also be applied to a case where the support member does not have a rotation mechanism, for example, a case where the flange portion has a rectangular shape as shown in Figures 5 to 7.

[0069] Furthermore, in the SiC single crystal manufacturing apparatus of the third embodiment and its modified example, the spacing between two adjacent crucibles in the transport direction is set to a distance that would cause the flange portions to come into contact with each other if left as is, but as in the SiC single crystal manufacturing apparatus of the second embodiment, the spacing between two adjacent crucibles in the transport direction may also be set to a distance that prevents the flange portions from coming into contact with each other.

[0070] FIG. 15 is a cross-sectional view of an example of an SiC single crystal manufacturing apparatus according to the fourth embodiment of the present invention, viewed from the front in the transfer direction. A continuous furnace 106 constituting the SiC single crystal manufacturing apparatus 6 shown in FIG. 15 contains a crucible 40, a support member 50, a lower heater 60, and a shielding member 90. That is, it can be said that this is an example in which flange portion 80 is removed from continuous furnace 102 constituting SiC single crystal manufacturing apparatus 2 shown in FIGS. 5 to 7, and shielding member 90 is provided instead.

[0071] Both the flange portion and the shielding member can block the heat from the lower heater from reaching the seed crystal placement portion. Therefore, even if only one of the flange portion and the shielding member is placed, an appropriate temperature gradient can be formed between the filling portion and the seed crystal placement portion, and a high-quality SiC single crystal with few defects and distortion can be obtained.

[0072] FIG. 16 is a top view schematically showing an example of an SiC single crystal manufacturing apparatus according to the fifth embodiment of the present invention. 16 comprises a continuous furnace 107, a decompression chamber 200 connected to an inlet 11 of the continuous furnace 107, and a pressure recovery chamber 300 connected to an outlet 13 of the continuous furnace 107. The continuous furnace 107, the decompression chamber 200, and the pressure recovery chamber 300 are each equipped with a pressure reduction mechanism (not shown) for reducing the pressure inside, and airtight doors 110 are provided between the continuous furnace 107 and the decompression chamber 200, and between the continuous furnace 107 and the pressure recovery chamber 300, respectively. It should be noted that a lower heater is disposed in the continuous furnace 107, but is omitted in FIG. The continuous furnace 107, the decompression chamber 200, and the pressure recovery chamber 300 each have a decompression mechanism, so that the pressure inside the continuous furnace 107 can be maintained constant. Furthermore, by providing airtight doors 110 between the continuous furnace 107 and the decompression chamber 200 and between the continuous furnace 107 and the pressure recovery chamber 300, it becomes easier to maintain a decompressed atmosphere inside the continuous furnace 107.

[0073] For example, a decompression chamber 200 is connected to the entrance 11 of the continuous furnace 107, and when the degree of vacuum in the decompression chamber 200 becomes approximately the same as the degree of vacuum inside the continuous furnace 107, the airtight door 110 between the decompression chamber 200 and the continuous furnace 107 is opened, and the crucible 40 can be transported from the decompression chamber 200 to the continuous furnace 107 without reducing the degree of vacuum inside the continuous furnace 107. At this time, only one crucible may be loaded at a time, or multiple crucibles may be loaded.

[0074] Furthermore, as long as the airtight door 110 between the reduced pressure chamber 200 and the entrance 11 of the continuous furnace 107 is closed, even if the reduced pressure chamber 200 is opened to the atmosphere, the degree of vacuum in the continuous furnace 107 is not reduced, so a new (untreated) crucible can be brought into the reduced pressure chamber 200 without stopping the operation of the continuous furnace 107.

[0075] Similarly, if the pressure recovery chamber 300 is connected to the outlet of the continuous furnace 107, the heated crucible 40 can be carried out through the pressure recovery chamber 300 without stopping the operation of the continuous furnace 107.

[0076] From the above, when the above configuration is satisfied, the crucible can be loaded before processing and unloaded after processing without stopping the operation of the continuous furnace 107, resulting in high utilization efficiency and energy efficiency of the equipment.

[0077] Examples of the pressure reducing mechanism include a rotary pump, an oil diffusion pump, and a turbo molecular pump.

[0078] FIG. 17 is a top view schematically showing an example of an SiC single crystal manufacturing apparatus according to the sixth embodiment of the present invention. The SiC single crystal manufacturing apparatus 8 shown in Figure 17 comprises a continuous furnace 108, a pre-treatment storage section 400 provided upstream of the inlet 11 of the continuous furnace 108, and a post-treatment storage section 500 provided downstream of the outlet 13 of the continuous furnace 108. It should be noted that a lower heater is disposed within the continuous furnace 108, but is omitted in FIG. If a pre-treatment storage section 400 is provided upstream of the inlet 11 of the continuous furnace 108, the crucible 40 can be stored before treatment. Also, if a post-treatment storage section 500 is provided downstream of the outlet 13 of the continuous furnace 108, the crucible 40 can be stored after treatment.

[0079] An airtight door may be provided between the pre-treatment storage section and the entrance of the continuous furnace, but it is preferable that no airtight door is provided. Similarly, an airtight door may be provided between the outlet of the continuous furnace and the post-treatment storage section, but an airtight door does not have to be provided.

[0080] The pre-treatment storage section may be provided upstream of the inlet of the continuous furnace, for example, upstream of a decompression chamber connected to the inlet of the continuous furnace. In this case, it is preferable to provide an airtight door between the pre-treatment storage section and the decompression chamber.

[0081] Similarly, the post-treatment storage section may be provided downstream of the outlet of the continuous furnace, for example, downstream of a pressure recovery chamber connected to the outlet of the continuous furnace. In this case, it is preferable to provide an airtight door between the pressure recovery chamber and the post-treatment storage section.

[0082] [SiC single crystal manufacturing method] The method for producing a SiC single crystal of the present invention is characterized by using the SiC single crystal production apparatus of the present invention. The method for producing a SiC single crystal of the present invention uses the SiC single crystal production apparatus of the present invention, and therefore can produce a SiC single crystal efficiently.

[0083] The present specification discloses the following:

[0084] The present disclosure (1) provides a continuous furnace having an inlet, an outlet, and a heating region provided between the inlet and the outlet, The continuous furnace is provided with a crucible having a filling section at its bottom for filling with a SiC solid raw material, a support member on which the crucible is placed and which transports the crucible sequentially from the inlet to the outlet, and a lower heater provided along the transport path of the crucible for heating the filling section of the crucible.

[0085] The present disclosure (2) is the SiC single crystal manufacturing apparatus according to the present disclosure (1), in which an upper heater is provided above the lower heater.

[0086] The present disclosure (3) is the SiC single crystal manufacturing apparatus according to the present disclosure (1) or (2), in which a shielding member is provided above the lower heater.

[0087] The present disclosure (4) is a SiC single crystal manufacturing apparatus that can be arbitrarily combined with any of the present disclosures (1) to (3), in which a flange portion that protrudes outward from the side surface of the crucible is provided at a position on the side surface of the crucible that is higher than the filling portion of the crucible.

[0088] The present disclosure (5) is the SiC single crystal manufacturing apparatus according to the present disclosure (4), wherein the flange portion has an annular shape.

[0089] The present disclosure (6) is the SiC single crystal manufacturing apparatus according to the present disclosure (4) or (5), wherein the heights of the flange portions of two crucibles adjacent to each other in the direction of conveyance of the crucibles are different.

[0090] The present disclosure (7) is a SiC single crystal manufacturing apparatus according to the present disclosure (4) or (5), in which the heights of the support surfaces on which the crucible is placed of the two support members adjacent to each other in the conveying direction of the crucible are different.

[0091] The present disclosure (8) is the SiC single crystal manufacturing apparatus according to the present disclosure (4) or (5), wherein the support surface of the support member on which the crucible is placed is inclined at a predetermined angle with respect to the transport direction of the crucible.

[0092] The present disclosure (9) is an SiC single crystal manufacturing apparatus in any combination with any of the present disclosures (1) to (8), wherein the support member includes a rotation mechanism for rotating the crucible.

[0093] The present disclosure (10) is a method for manufacturing a continuous furnace, wherein the continuous furnace is provided with a decompression mechanism for decompressing the inside thereof, The continuous furnace further includes a decompression chamber connected to the inlet and a pressure recovery chamber connected to the outlet, The SiC single crystal manufacturing apparatus is an optional combination of any of the present disclosures (1) to (9), and has airtight doors provided between the continuous furnace and the decompression chamber, and between the continuous furnace and the pressure recovery chamber.

[0094] The present disclosure (11) provides a method for manufacturing a continuous furnace, the method comprising: providing a pre-treatment storage section upstream of the inlet of the continuous furnace for storing the crucible before heating; The SiC single crystal manufacturing apparatus is an SiC single crystal manufacturing apparatus that can be arbitrarily combined with any of the present disclosures (1) to (10), and further includes a post-treatment storage section that stores the crucible after heating, located downstream of the outlet of the continuous furnace.

[0095] The present disclosure (12) is a method for producing a SiC single crystal, characterized by using an SiC single crystal production apparatus in any combination with any of the present disclosures (1) to (11). [Explanation of symbols]

[0096] 1, 2, 3, 4, 5, 6, 7, 8 SiC single crystal manufacturing equipment 10. Cabinet 11 Entrance 13 Exit 15. Insulation 30 heating area 40 Crucible 41 Filling section 43 Seed crystal arrangement part 50 Support member 51 Placement section 51a Placement surface 53 Support part 53a Through hole 60 Lower heater 70 Upper heater 80 Flange part (square) 80a: The part of the flange that comes into contact with the crucible (inner edge) 80b: The part of the flange that does not come into contact with the crucible (outer edge) 81 Flange part (annular) 90 Shielding material 101, 102, 103, 104, 105, 106, 107, 108 Continuous furnace 110 Airtight Door 141 SiC solid raw material 143 Seed Crystal 200 Decompression Chamber 300 Recompression chamber 400 Pre-processing storage section 500 Post-processing storage section h1, h2 flange height h3: Difference in height between the placement surfaces of adjacent support members in the conveying direction θ Inclination angle of the loading surface relative to the conveying direction

Claims

1. a continuous furnace having an inlet, an outlet, and a heating zone disposed between the inlet and the outlet; a crucible having a filling portion at its lower portion for filling with a SiC solid raw material, a support member on which the crucible is placed and which transports the crucible sequentially from the inlet to the outlet, and a lower heater provided along the transport path of the crucible and which heats the filling portion of the crucible, within the continuous furnace;

2. 2. The SiC single crystal manufacturing apparatus according to claim 1, further comprising an upper heater provided above said lower heater.

3. The SiC single crystal manufacturing apparatus according to claim 1 , wherein a shielding member is provided above the lower heater.

4. 2. The SiC single crystal manufacturing apparatus according to claim 1, wherein a flange portion protruding outward from the side surface of the crucible is provided on the side surface of the crucible at a position above the filling portion of the crucible.

5. The SiC single crystal manufacturing apparatus according to claim 4 , wherein the flange portion has an annular shape.

6. 5. The SiC single crystal manufacturing apparatus according to claim 4, wherein the flange portions of two crucibles adjacent to each other in the direction of crucible transfer are different in height.

7. 5. The SiC single crystal manufacturing apparatus according to claim 4, wherein the heights of the mounting surfaces on which the crucible is placed of two of the support members adjacent to each other in the direction of conveyance of the crucible are different.

8. 5. The SiC single crystal manufacturing apparatus according to claim 4, wherein a mounting surface of said support member on which said crucible is mounted is inclined at a predetermined angle with respect to a direction in which said crucible is transported.

9. The SiC single crystal manufacturing apparatus according to claim 1 , wherein the support member includes a rotation mechanism that rotates the crucible.

10. the continuous furnace is provided with a decompression mechanism for decompressing the interior thereof, The continuous furnace further includes a decompression chamber connected to the inlet and a pressure recovery chamber connected to the outlet, 2. The SiC single crystal manufacturing apparatus according to claim 1, wherein an airtight door is provided between the continuous furnace and the decompression chamber, and between the continuous furnace and the pressure recovery chamber.

11. a pre-treatment storage section for storing the crucible before heating is provided upstream of the inlet of the continuous furnace; 2. The SiC single crystal manufacturing apparatus according to claim 1, further comprising a post-treatment storage section for storing the crucible after heating, provided downstream of the outlet of the continuous furnace.

12. A method for producing a SiC single crystal, comprising using the SiC single crystal production apparatus according to any one of claims 1 to 11.

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