JP2013216514A - Method of manufacturing silicon carbide single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a growth surface of an SiC single crystal becoming a concave shape, to reduce a curvature of the recessed shape at least, and to make the growth surface become a projecting shape desirably.SOLUTION: A third heat insulating material 16 is provided to protrude from an inner periphery wall surface of a heating vessel 8 enclosing a pedestal 9. As a result, a temperature of an outer edge of an SiC single crystal 20 can be pulled to a temperature of the third heat insulating material 16, and that a growth surface of the SiC single crystal 20 becomes a recessed shape can be controlled. Therefore, generation of stress in an intracrystalline part of the SiC single crystal 20 can be controlled, and quality can be prevented from being deteriorated by generation of crystal defect (dislocation) or the like.

Description

  The present invention relates to a method for producing a SiC single crystal in which a SiC single crystal is produced by supplying a raw material gas to a seed crystal composed of a silicon carbide (hereinafter referred to as SiC) single crystal.

  Conventionally, Patent Documents 1 and 2 disclose a method for producing a SiC single crystal in which a SiC single crystal is grown by supplying a source gas to a seed crystal. According to this method for producing a SiC single crystal, by supplying the source gas into a bottomed cylindrical reaction vessel in which the central portion of the bottom is a gas inlet and the upper portion is opened, the upper portion of the reaction vessel An SiC single crystal is grown on the seed crystal arranged in the above.

JP 2002-154898 A JP 2003-306398 A

  When the SiC single crystal is manufactured, the growth surface of the SiC single crystal is flat or has a convex shape protruding slightly from the outer edge at the central portion rather than a concave shape that is recessed from the outer edge at the central portion. It is preferable to do so. When the growth surface of the SiC single crystal becomes concave, stress is generated inside the crystal, and the quality is deteriorated due to generation of crystal defects (dislocations). For this reason, even if the growth surface of the SiC single crystal has a concave shape, it is more preferable that the curvature is smaller if the growth surface is flat or slightly convex.

  In order to control the growth surface of the SiC single crystal, a guide is arranged so as to surround the SiC single crystal, and the temperature of the outer edge of the SiC single crystal is made higher than the inside by the heat of the guide. Can be considered. Specifically, a cylindrical guide may be extended from above the reaction vessel so that a SiC single crystal is grown along the inner peripheral surface of the guide. In this way, the temperature distribution of the SiC single crystal changes sharply from the central part to the outer edge part, and the outer edge part can be made higher in temperature than the central part. Thereby, even if the growth surface of the SiC single crystal has a concave shape, the concave amount of the concave portion is reduced and the curvature can be reduced.

  However, when a cylindrical guide is extended from above the reaction vessel, it is difficult to give a temperature distribution to the guide in the growth direction of the SiC single crystal, and it is difficult to affect the distribution of the crystal surface of the SiC single crystal. That is, the temperature decreases as it goes above the reaction vessel, but the temperature of the guide is pulled to the temperature above that, and the expected high temperature cannot be sufficiently achieved, and the temperature rapidly increases from the center to the outer edge of the SiC single crystal. No longer changes. As a result, the surface of the SiC single crystal becomes concave due to the temperature balance with the reaction vessel.

  In view of the above points, the present invention further suppresses the growth surface of the SiC single crystal from becoming concave, and at least reduces the curvature of the concave shape, preferably so that the growth surface becomes flat or slightly convex. The purpose is to.

  In order to achieve the above object, according to the first aspect of the present invention, a seed crystal (5) made of a SiC single crystal substrate is installed on the pedestal (9), and the periphery of the pedestal is heated by a heating device (13). The SiC single crystal (20) is grown on the surface of the seed crystal by supplying the SiC source gas (3a) from below to the surface of the seed crystal, and the pedestal is pulled up by the pulling mechanism (11). In the manufacturing method of the SiC single crystal in which the SiC single crystal is elongated, the heat insulating material (16) surrounding the outer peripheral portion of the pedestal is disposed so as to protrude from the inner wall surface of the heating container (8), and the pedestal is formed with the heat insulating material. The SiC single crystal is crystal-grown in a state of surrounding the structure.

  Thus, by providing the heat insulating material so as to protrude from the inner peripheral wall surface of the heating container while surrounding the pedestal, the temperature of the outer edge portion of the SiC single crystal can be pulled to the temperature of the heat insulating material, and the growth of the SiC single crystal It can suppress that the surface becomes concave shape. At least the curvature of the concave shape of the growth surface of the SiC single crystal can be reduced, and preferably the growth surface can be flat or slightly convex.

  Specifically, as described in claim 2, when the SiC single crystal is grown in a state where the lower end surface of the heat insulating material is positioned at the same height as or higher than the growth surface of the SiC single crystal, It becomes possible to reduce the concave curvature of the growth surface of the SiC single crystal. In particular, as described in claim 3, the SiC single crystal in a state in which the distance from the lower end surface of the heat insulating material to the growth surface of the SiC single crystal is in the range of 0 to 50 mm in the growth direction of the SiC single crystal. When crystal is grown, the growth surface of the SiC single crystal can be made flat or slightly convex.

  In addition, as described in claim 5, if the SiC single crystal is grown in a state where the lower end surface of the heat insulating material is located below the growth surface of the SiC single crystal, the source gas is introduced from a lower position. Since it can be made to collect in a center part, it becomes possible to increase the gas yield which contributes to the crystal growth of a SiC single crystal.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows an example of a corresponding relationship with the specific means as described in embodiment mentioned later.

It is sectional drawing of the SiC single crystal manufacturing apparatus 1 concerning 1st Embodiment of this invention. It is a graph which shows the result of having investigated the temperature of the growth surface of the SiC single crystal. It is sectional drawing of the SiC single crystal manufacturing apparatus 1 concerning 2nd Embodiment of this invention. It is sectional drawing of the SiC single crystal manufacturing apparatus 1 concerning 3rd Embodiment of this invention. It is sectional drawing of the SiC single crystal manufacturing apparatus 1 concerning 4th Embodiment of this invention. 6 is a graph showing a result of examining a temperature with respect to a distance from a gas high temperature portion inside a heating container 8 to a growth surface of a SiC single crystal 20.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
As shown in FIG. 1, the SiC single crystal manufacturing apparatus 1 supplies a source gas 3a from a source gas supply source 3 through an inlet 2 provided at the bottom and out of the source gas 3a through an outlet 4 at the top. Unreacted gas is discharged. Then, the SiC single crystal manufacturing apparatus 1 forms an ingot of the SiC single crystal 20 by growing the SiC single crystal 20 on the seed crystal 5 made of the SiC single crystal substrate disposed in the apparatus.

  The SiC single crystal manufacturing apparatus 1 includes a source gas supply source 3, a vacuum container 6, a first heat insulating material 7, a heating container 8, a pedestal 9, a second heat insulating material 10, a rotary pulling gas supply mechanism 11, a first and a first Two heating devices 12 and 13, a purge gas supply source 14, and a third heat insulating material 16 are provided.

  The source gas supply source 3 supplies an SiC source gas 3 a containing Si and C together with a carrier gas (for example, a mixed gas of a silane-based gas such as silane and a hydrocarbon-based gas such as propane) from the inlet 2.

  The vacuum vessel 6 is made of quartz glass or the like, has a hollow cylindrical shape, can introduce and lead the carrier gas and the source gas 3a, and accommodates other components of the SiC single crystal manufacturing apparatus 1. The structure is such that the internal space in which it is housed can be depressurized by evacuating it. The inlet 2 of the source gas 3a is provided at the bottom of the vacuum vessel 6, and the outlet 4 of the source gas 3a is provided at the upper part (specifically, the position above the side wall).

  The first heat insulating material 7 has a cylindrical shape, is disposed coaxially with respect to the vacuum vessel 6, and constitutes a raw material gas introduction pipe 7 a with a hollow portion. The first heat insulating material 7 is made of, for example, graphite or graphite whose surface is coated with a refractory metal carbide such as TaC (tantalum carbide) or NbC (niobium carbide) so that thermal etching can be suppressed. Yes.

  Heating vessel 8 is formed in a hollow shape, and constitutes a reaction chamber in which SiC single crystal 20 is grown on the surface of seed crystal 5. The heating container 8 is made of, for example, graphite or graphite whose surface is coated with a refractory metal carbide such as TaC (tantalum carbide) or NbC (niobium carbide), so that thermal etching can be suppressed. The heating container 8 is arranged from the upstream side in the flow direction of the raw material gas 3 a to the downstream side with respect to the base 9 so as to surround the base 9. By this heating container 8, the raw material gas 3 a is decomposed while excluding particles contained in the raw material gas 3 a until the raw material gas 3 a supplied from the inlet 2 is led to the seed crystal 5.

  Specifically, the heating container 8 has a structure having a hollow cylindrical member, and in the case of the present embodiment, the heating container 8 is composed of a bottomed cylindrical member. The heating vessel 8 is provided with a gas introduction port 8a that communicates with the hollow portion of the first heat insulating material 7 at the bottom, and the source gas 3a that has passed through the hollow portion of the first heat insulating material 7 is heated through the gas introduction port 8a. It is introduced into the container 8.

  Further, a purge gas introduction hole 8 b is provided on the inner peripheral wall surface of the heating container 8 on the upstream side of the pedestal 9 in the flow direction of the raw material gas 3 a. A purge gas 15 supplied from a purge gas supply source 14 to be described later is introduced into the heating container 8 through the purge gas introduction hole 8b and flows through a gap between the heating container 8 and the base 9. The purge gas introduction hole 8 b is formed so as to surround the entire inner circumference of the heating container 8, and introduces the purge gas 15 so as to surround the circumference of the base 9.

  The pedestal 9 is composed of a plate-like member that is arranged coaxially with the central axis of the heating container 8. For example, the pedestal 9 is made of graphite or graphite whose surface is coated with a refractory metal carbide such as TaC (tantalum carbide) or NbC (niobium carbide) so that thermal etching can be suppressed. A seed crystal 5 is attached to the pedestal 9, and a SiC single crystal 20 is grown on the surface of the seed crystal 5. The pedestal 9 has a shape corresponding to the shape of the seed crystal 5 to be grown, for example, a disk shape, and is connected to the rotary pulling gas supply mechanism 11 on the surface opposite to the surface on which the seed crystal 5 is disposed.

  The second heat insulating material 10 constitutes an outer peripheral heat insulating material that guides the purge gas 15 into the heating container 8 while surrounding the outer periphery of the heating container 8 and the pedestal 9. In the present embodiment, the second heat insulating material 10 is formed in a cylindrical shape, for example, graphite or graphite whose surface is coated with a refractory metal carbide such as TaC (tantalum carbide) or NbC (niobium carbide). As a result, thermal etching can be suppressed. The inner diameter of the second heat insulating material 10 is made larger than the outer diameters of the first heat insulating material 7 and the heating container 8, and a gap for introducing the purge gas 15 is formed between them. Although not shown in the drawing, the inner diameter of the second heat insulating material 10 can be reduced upward, and with such a configuration, the purge gas 15 can escape more toward the purge gas introduction hole 8b.

  The rotary pulling gas supply mechanism 11 rotates and pulls up the pedestal 9 through the pipe material 11a. One end of the pipe material 11 a is connected to the surface of the pedestal 9 on the side opposite to the attaching surface of the seed crystal 5, and the other end is connected to the main body of the rotary pulling gas supply mechanism 11. The pipe material 11a is also made of, for example, graphite or graphite whose surface is coated with a refractory metal carbide such as TaC (tantalum carbide), so that thermal etching can be suppressed. With such a configuration, the pedestal 9, the seed crystal 5 and the SiC single crystal 20 can be rotated and pulled together with the pipe material 11a, and the SiC single crystal 20 is grown while the growth surface of the SiC single crystal 20 has a desired temperature distribution. The growth surface temperature can always be adjusted to a temperature suitable for growth.

  Further, the rotary pulling gas supply mechanism 11 introduces the purge gas 15 into the pipe material 11a, and supplies the purge gas 15 to the back side of the base 9 connected to the tip of the pipe material 11a. Specifically, a gas introduction hole 11b is formed at the tip position on the base 9 side of the pipe material 11a, and the purge gas 15 is supplied to the back side of the base 9 through the gas introduction hole 11b. A plurality of gas introduction holes 11 b are provided at equal intervals in the circumferential direction of the pipe material 11 a, and the purge gas 15 can be supplied to almost the entire back surface of the base 9. The purge gas 15 supplied from the rotary pulling gas supply mechanism 11 is caused to flow radially outward on the back side of the base 9, and then the unreacted gas in the raw material gas 3a and a purge gas supply source 14 to be described later. Is guided to the outlet 4 side based on the flow of the purge gas 15 supplied from. In this way, by introducing the purge gas 15 from the rotary pulling gas supply mechanism 11 to the back side of the pedestal 9, the source gas 3 a can be prevented from wrapping around the back side of the pedestal 9. Polycrystalline precipitation is suppressed.

  The first and second heating devices 12 and 13 are constituted by, for example, a heating coil (induction heating coil or direct heating coil), and are arranged so as to surround the vacuum vessel 6. In the case of this embodiment, the 1st, 2nd heating apparatuses 12 and 13 are comprised by the coil for induction heating, for example, it is set as the structure which can cool the inside by water with the coil for induction heating. These 1st, 2nd heating apparatuses 12 and 13 are constituted so that temperature control can be carried out independently, respectively, and the 1st heating apparatus 12 is arranged in the position corresponding to the lower part of heating container 8, The second heating device 13 is disposed at a position corresponding to the base 9. Therefore, the temperature of the lower part of the heating container 8 can be controlled by the first heating device 12, and the temperature around the pedestal 9, the seed crystal 5 and the SiC single crystal 20 can be controlled by the second heating device 13. .

The purge gas supply source 14 supplies the purge gas 15. The purge gas 15 is composed of an inert gas such as Ar or He, or an etching gas such as H ₂ or HCl, and functions as an adhesion preventing gas for preventing the deposition of SiC polycrystal. The purge gas 15 supplied from the purge gas supply source 14 passes through the gap between the outer peripheral wall of the first heat insulating material 7 and the heating container 8 and the inner peripheral wall of the second heat insulating material 10, and enters the heating container 8 through the purge gas introduction hole 8 b. To be introduced.

  The third heat insulating material 16 is disposed so as to surround the outer peripheral portion of the base 9. The third heat insulating material 16 is made of, for example, graphite such as felt carbon having a relatively low density, and the surface thereof has a higher density than that of graphite (for example, graphite sheet such as graphoil and Nika film (both are registered trademarks)), TaC ( (Tantalum carbide) or NbC (niobium carbide) coated with a refractory metal carbide, so that the third heat insulating material 16 is composed only of relatively thin graphite such as felt carbon. , It is suppressed that unreacted gas is absorbed and polycrystallized.

  In the present embodiment, the installation start position of the third heat insulating material 16, that is, the lower end surface is the growth surface of the SiC single crystal 20 (the seed crystal 5 attached to the surface of the base 9 at the stage before the growth of the SiC single crystal 20. From the surface), for example, within a range of 0 to 50 mm from the surface of the SiC single crystal 20. Further, the installation end position of the third heat insulating material 16, that is, the upper end surface is set to the back surface of the base 9 or above it. Specifically, the thickness of the third heat insulating material 16 is set to be equal to or greater than the thickness of the pedestal 9 and equal to or less than the growth amount planned when the SiC single crystal 20 is grown long.

  The third heat insulating material 16 is installed on the outer periphery of the pedestal 9 so as to be disposed up to a predetermined distance from the side surface of the SiC single crystal 20 that protrudes from the inner wall surface of the heating container 8 and grows. The temperature in the vicinity of the same height as 9 is transmitted, and the arrangement becomes higher. In the case of this embodiment, the 3rd heat insulating material 16 is comprised by the ring-shaped thing, the heating container 8 and the 2nd heat insulating material 10 are divided | segmented up and down, and 3rd heat insulation is carried out between the divided | segmented lower part and upper part. The material 16 is installed. By setting it as such a structure, the 3rd heat insulating material 16, the heating container 8, and the 2nd heat insulating material 10 can be made into a simple structure, and replacement | exchange of the 3rd heat insulating material 16 can also be performed easily.

  With this structure, the SiC single crystal manufacturing apparatus 1 according to the present embodiment is configured. Then, the manufacturing method of the SiC single crystal 20 using the SiC single crystal manufacturing apparatus 1 concerning this embodiment is demonstrated.

  First, the seed crystal 5 is attached to the pedestal 9 and installed in the heating container 8. At this time, the lower end surface of the third heat insulating material 16 is arranged at the same height or higher than the surface of the seed crystal 5, for example, at a position of 0 to 50 mm from the surface of the seed crystal 5. .

  And the 1st, 2nd heating apparatuses 12 and 13 are controlled and desired temperature distribution is attached. That is, the source gas 3a is recrystallized on the surface of the seed crystal 5 so that the SiC single crystal grows and the sublimation rate becomes higher in the heating vessel 8 than the recrystallization rate. To do. By doing in this way, the surface side of the seed crystal 5 which should grow the SiC single crystal 20 is heated. Moreover, since the arrangement position of the 2nd heating apparatus 13 is a position corresponding to the base 9, the back surface side of the base 9 can be prevented from being heated so much.

In addition, the source gas 3a is introduced through the source gas introduction pipe 7a while introducing a carrier gas using an inert gas such as Ar or He or an etching gas such as H ₂ or HCl while bringing the vacuum vessel 6 to a desired pressure. To do. Thereby, source gas 3a flows as shown by an arrow in FIG. 1, and is supplied to seed crystal 5 to grow SiC single crystal 20. Then, the base 9, the seed crystal 5, and the SiC single crystal 20 are rotated through the pipe material 11 a by the rotary pulling gas supply mechanism 11, and pulled up according to the growth rate of the SiC single crystal 20. Thereby, the height of the growth surface of SiC single crystal 20 is kept substantially constant, and the temperature distribution of the growth surface temperature can be controlled with good controllability.

  Further, the purge gas 15 is introduced from the purge gas supply source 14 through the purge gas introduction hole 8b. As a result, the purge gas 15 is caused to flow toward the outlet 4 through the purge gas introduction hole 8b and the pedestal 9 or between the SiC single crystal 20 and the heating vessel 8 as shown by the arrows in FIG. Further, the purge gas 15 is also introduced from the rotary pulling gas supply mechanism 11 through the pipe material 11a and the gas introduction hole 11b. As a result, as indicated by the arrow in FIG. 1, the purge gas 15 is guided to the back side of the pedestal 9 and then flows radially outward of the pedestal 10. Since the purge gas 15 is introduced in this way, it is possible to suppress the deposition of SiC polycrystals between the pedestal 9 and the heating container 8 or the third heat insulating material 16 or on the back surface of the pedestal 9.

  In this way, the SiC single crystal 20 is grown. Since the third heat insulating material 16 is provided so as to protrude from the inner peripheral wall of the heating container 8 while surrounding the pedestal 9, the crystal surface of the SiC single crystal 20 is The temperature is pulled to the temperature of the third heat insulating material 16. That is, since the temperature of the heating container 8 that is induction-heated by the second heating device 13 is higher than that inside, the portion of the SiC single crystal 20 near the third heat insulating material 16 is the third. The temperature rises due to the heat of the heat insulating material 16. And since the 3rd heat insulating material 16 is equipped so that it may protrude from the inner peripheral wall of the heating container 8, the temperature of the heating container 8 near the same height as the base 9 is transmitted to the 3rd heat insulating material 16. Based on the fact that the temperature of the heating container 8 is gradually lowered from below to above, this temperature is higher than that above the heating container 8 that is the lowest temperature. For this reason, by providing the third heat insulating material 16 so as to protrude from the inner peripheral wall of the heating container 8 as in this embodiment, compared to the case where the third heat insulating material 16 is extended from above the heating container 8, Further, the outer edge portion of the SiC single crystal 20 can be heated to a high temperature.

  Therefore, the temperature of the outer edge portion of the growth surface of SiC single crystal 20 can be made higher than before, and the growth rate can be suppressed, so that the growth surface of SiC single crystal 20 has a concave shape. It becomes possible to suppress becoming. More preferably, the growth surface of SiC single crystal 20 can be flat or slightly convex.

  When the temperature of the growth surface of the SiC single crystal 20 was examined, the result shown in FIG. 2 was obtained. In this figure, x represents the distance from the center of the SiC single crystal 20, and y represents the distance from the growth surface of the SiC single crystal 20 in the growth direction of the SiC single crystal 20 to the lower end surface of the third heat insulating material 16. Show.

  As shown in this figure, in the normal state (conventional) in which the third heat insulating material 16 was not provided, the outer edge portion of the growth surface of the SiC single crystal 20 was lowered by about 20 ° C. compared to the central portion. For this reason, it is considered that the SiC single crystal 20 has a growth rate larger in the outer edge portion than in the central portion, and the growth surface has a concave shape. On the other hand, when the 3rd heat insulating material 16 like this embodiment is provided, it turns out that the temperature of the growth surface of the SiC single crystal 20 can be made substantially constant when y = 0 mm. Furthermore, when y = 25 mm and 50 mm, it can be seen that the temperature of the outer edge portion of SiC single crystal 20 is higher than that of the central portion.

  Therefore, by providing the third heat insulating material 16, it is possible to suppress the growth surface of the SiC single crystal 20 from becoming a concave shape, and even if it becomes a concave shape, the curvature can be reduced compared to the conventional case. . The growth surface of the SiC single crystal 20 can be made substantially flat when y = 0 mm or more, and the growth surface of the SiC single crystal 20 can be made convex when y = 25 mm or more. However, as can be seen from FIG. 2, when y = 25 mm and y = 50 mm are compared, the temperature of the outer edge portion of SiC single crystal 20 is higher when y = 25 mm. For this reason, even if the distance from the growth surface of the SiC single crystal 20 to the lower end surface of the third heat insulating material 16 becomes too large beyond y = 50 mm, the temperature of the outer edge portion of the SiC single crystal 20 is the third heat insulating material. It is preferable that y = 50 mm or less because it will not be pulled at a temperature of 16.

  As described above, by providing the third heat insulating material 16 so as to protrude from the inner peripheral wall surface of the heating container 8 while surrounding the base 9, the temperature of the outer edge portion of the SiC single crystal 20 becomes the temperature of the third heat insulating material 16. It can be pulled and can suppress that the growth surface of SiC single crystal 20 becomes concave. Specifically, at least the curvature of the concave shape of the growth surface of the SiC single crystal 20 can be reduced, and preferably, the growth surface can be flat or slightly convex. Therefore, it is possible to suppress the generation of stress inside the crystal of SiC single crystal 20, and it is possible to prevent the quality from being deteriorated due to the occurrence of crystal defects (dislocations).

(Second Embodiment)
A second embodiment of the present invention will be described. In the present embodiment, the configuration of the third heat insulating material 16 is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, only different portions from the first embodiment will be described. .

  As shown in FIG. 3, in the present embodiment, the third heat insulating material 16 is attached to the inner wall surface of the heating container 8. For example, the third heat insulating material 16 can be fixed to the inner wall surface of the heating container 8 by forming a gap, a groove, or a mounting hole in the heating container 8 and fitting it into the heating container 8. Thus, even if it attaches the 3rd heat insulating material 16 with respect to the heating container 8, the effect similar to 1st Embodiment can be acquired.

(Third embodiment)
A third embodiment of the present invention will be described. In this embodiment, the configuration of the third heat insulating material 16 is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, only different portions from the first embodiment will be described. .

  As shown in FIG. 4, in the present embodiment, the third heat insulating material 16 is divided into a plurality of pieces in the growth direction of the SiC single crystal 20, and a gap is formed between the divided third heat insulating materials 16. . As shown in the present embodiment, it is possible to divide the third heat insulating material 16 into a plurality of pieces, but by providing a gap between the divided third heat insulating materials 16, The temperature in between can be divided, and the temperature distribution change can be changed. For example, as the length of the third heat insulating material 16 in the growth direction of the SiC single crystal 20 becomes longer, the temperature of the lower portion may be lowered due to the influence of the temperature of the upper portion. Therefore, by dividing the third heat insulating material 16 as in the present embodiment, it is possible to prevent the temperature of the third heat insulating material 16 that is disposed below from being lowered. Thereby, it becomes possible to raise the temperature of the outer edge part of the SiC single crystal 20 that is affected by the temperature of the third heat insulating material 16 that is arranged below, and the effects shown in the first embodiment can be further improved. Can be obtained.

  In addition, when dividing | segmenting the 3rd heat insulating material 16 into plurality in this way, each can also be made into a heat insulating material from which heat insulation performance differs. In that case, it becomes possible to obtain the above effect more by arranging ones having different heat insulation performance such as arranging one having higher heat insulation performance below.

(Fourth embodiment)
A fourth embodiment of the present invention will be described. In this embodiment, the configuration of the third heat insulating material 16 is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, only different portions from the first embodiment will be described. .

  As shown in FIG. 5, in the present embodiment, the third heat insulating material 16 is extended in the growth direction of the SiC single crystal 20, and the installation start position of the third heat insulating material 16, that is, the lower end surface is the growth of the SiC single crystal 20. It is located below the surface.

  In this way, since the source gas 3a can be collected from the lower position to the central portion, in addition to obtaining the same effect as the first embodiment, the gas contributing to the crystal growth of the SiC single crystal 20 The yield can be increased. Moreover, the temperature with respect to the distance from the gas high temperature part inside the heating container 8 to the growth surface of the SiC single crystal 20 is set for each of the case where the third heat insulating material 16 is provided and the case where the third heat insulating material 16 is not provided as in the present embodiment. As a result of the examination, the results shown in FIG. 6 were obtained. Note that the gas high temperature portion is a place where the temperature becomes the highest temperature (for example, a temperature exceeding 2300 ° C.) by the heating of the first heating device 12, and in the case of this embodiment, the installation of the third heat insulating material 16 is started. Near the position.

  As shown in this figure, when the third heat insulating material 16 is provided, the high temperature is maintained at the place where the third heat insulating material 16 is provided, as compared with the case where the third heat insulating material 16 is not provided. For this reason, it becomes possible to realize a steep temperature distribution in the growth direction of the SiC single crystal 20. As a result, it becomes possible to suppress nucleation in the gas phase and adhesion of SiC polycrystal to the side wall of the heating vessel 8.

(Other embodiments)
In the above embodiment, as the SiC single crystal manufacturing apparatus 1, after the source gas 3 a is supplied to the growth surface of the SiC single crystal 20, it passes through the outer peripheral surface of the SiC single crystal 20 and the side of the pedestal 9 and is discharged further upward. The method (upflow method) is described as an example. However, the present invention is not limited to this, and a return flow method in which the source gas 3a is supplied to the growth surface of the SiC single crystal 20 and then returned again in the same direction as the supply direction, or the source gas 3a is applied to the growth surface of the SiC single crystal 20. It can also be applied to a method (side flow method) in which the gas is discharged in the outer peripheral direction of the heating container 8 after being supplied.

  The present invention can also be applied to a growth method different from the gas supply method growth for supplying the source gas 3a. That is, SiC raw material powder is placed in advance in a crucible placed in a vacuum vessel, a raw material gas obtained by sublimating the SiC raw material from the SiC raw material powder is generated by heating with a heating device, and an SiC single crystal is formed on the seed crystal surface. The present invention can also be applied to sublimation growth for growth.

  Furthermore, in the above embodiment, the rotary pulling gas supply mechanism 11 capable of rotating and pulling the pedestal 9 and introducing the purge gas 15 is taken as an example. However, any pulling mechanism capable of at least pulling may be used.

DESCRIPTION OF SYMBOLS 1 Single crystal manufacturing apparatus 3 Raw material gas supply source 3a Raw material gas 5 Seed crystal 8 Heating container 9 Base 10 Second heat insulating material 11 Rotating pulling gas supply mechanism 12, 13 First, second heating device 14 Purge gas supply source 15 Purge gas 16 Third heat insulating material 20 SiC single crystal

Claims (7)

A hollow heating vessel (8) constituting the reaction chamber;
A pedestal (9) disposed in the heating vessel;
A heating device (13) that is disposed at a position corresponding to the pedestal of the outer periphery of the heating container and heats the heating container;
Using a manufacturing apparatus (1) having a pulling mechanism (11) for pulling up the pedestal upward,
A seed crystal (5) made of a silicon carbide single crystal substrate is placed on the pedestal, and a silicon carbide source gas (3a) is applied to the surface of the seed crystal from below while heating the periphery of the pedestal with the heating device. The silicon carbide single crystal (20) is crystal-grown on the surface of the seed crystal by supplying, and the silicon carbide single crystal is elongated by pulling up the pedestal by the pulling mechanism A manufacturing method of
A heat insulating material (16) surrounding the outer periphery of the pedestal is disposed so as to protrude from the inner wall surface of the heating container, and the silicon carbide single crystal is grown in a state of surrounding the pedestal with the heat insulating material. A method for producing a silicon carbide single crystal.   2. The carbonization of claim 1, wherein the silicon carbide single crystal is grown in a state in which a lower end surface of the heat insulating material is positioned at the same height as or higher than a growth surface of the silicon carbide single crystal. A method for producing a silicon single crystal.   The silicon carbide single crystal is grown in a state in which the distance from the lower end surface of the heat insulating material to the growth surface of the silicon carbide single crystal is in the range of 0 to 50 mm in the growth direction of the silicon carbide single crystal. The method for producing a silicon carbide single crystal according to claim 2.   4. The silicon carbide according to claim 1, wherein the thickness of the heat insulating material is equal to or greater than the thickness of the pedestal and equal to or less than a growth amount of the silicon carbide single crystal that is expected when grown. 5. A method for producing a single crystal.   2. The method for producing a silicon carbide single crystal according to claim 1, wherein the silicon carbide single crystal is grown in a state where a lower end surface of the heat insulating material is located below a growth surface of the silicon carbide single crystal. .   6. The method for manufacturing a silicon carbide single crystal according to claim 1, wherein the heat insulating material is divided into a plurality of parts in the growth direction of the silicon carbide single crystal.   The method for producing a silicon carbide single crystal according to claim 6, wherein a gap is provided between the plurality of heat insulating materials.

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