JP5278302B2 - Method and apparatus for producing silicon carbide single crystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing clogging in an outlet of a source gas by suppressing growth of an unnecessary SiC polycrystal formed in a place other than a crystal growth surface in a reaction vessel without using an etching gas. <P>SOLUTION: A first inlet passage 9d extending along the center axis of a reaction vessel 9 is disposed on the outer periphery of a hollow part 9c of the reaction vessel 9, and a first outlet passage 9i that connects the first inlet passage 9d and the hollow part 9c of the reaction vessel 9 is disposed on a side part 9e of the reaction vessel 9. By allowing an inert gas 15 to flow from the first outlet passage 9i via the first inlet passage 9d into the hollow part 9c of the reaction vessel 9, a source gas 3 is diluted, which passes through between the inner wall 9m of the reaction vessel 9 and a base 10. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an SiC single crystal manufacturing method and an apparatus for manufacturing an SiC single crystal by supplying a raw material gas to a seed crystal composed of a silicon carbide (hereinafter referred to as SiC) single crystal. .

  Conventionally, a method for growing a SiC single crystal on a seed crystal placed on a pedestal by supplying a raw material gas into a reaction vessel having an inlet having an opening at the center of the bottom and an outlet having an opening at the top. Has been proposed (see, for example, Patent Document 1).

  However, in this growth, the source gas that could not contribute to the crystal growth becomes polycrystallized on the side surface of the base or the inner wall of the reaction vessel. For this reason, the SiC polycrystal clogs the gap between the pedestal serving as the source gas outlet and the inner wall of the reaction vessel, or falls to the bottom of the reaction vessel and closes the source gas supply port. There was a problem that continuous / long growth of SiC single crystal was impossible.

  Therefore, for example, Patent Document 2 proposes a technique for suppressing the growth of unnecessary SiC polycrystals at a place other than the crystal growth surface of the SiC single crystal. Specifically, in Patent Document 2, by introducing an etching gas or an inert gas for etching SiC into the growth vessel from outside the growth vessel through a hole penetrating the wall of the reaction vessel, the side surface of the pedestal or the reaction vessel A method for suppressing the growth of SiC polycrystals on the inner wall of the metal has been proposed.

JP 2002-154898 A JP 2002-362998 A

  However, in the technique described in Patent Document 2, the etching gas for etching the SiC polycrystal etches the growing SiC single crystal, and even if it is an inert gas, the introduction position and introduction method of the gas are limited. Unless this is done, there is a problem that the SiC crystal surface is not saturated and the growth rate of the SiC single crystal is reduced.

  In view of the above points, the present invention suppresses the growth of unnecessary SiC polycrystals that are formed in a place other than the crystal growth surface in the reaction vessel by the introduction position and introduction method of the inert gas, thereby allowing the outlet of the source gas to be discharged. The first object is to prevent clogging of the gap between the side surface of the base and the inner wall of the reaction vessel. Another object of the present invention is to provide a manufacturing apparatus that can prevent clogging of the outlet of the source gas.

  In order to achieve the above object, according to the first aspect of the present invention, the first introduction passage (9d) is formed on the outer periphery of the hollow portion (9c) of the reaction vessel (9) along the central axis of the reaction vessel (9). And a first outlet passage (9i) for connecting the first introduction passage (9d) and the hollow portion (9c) of the reaction vessel (9) to the side portion (9e) of the reaction vessel (9). Yes.

  Then, by flowing an inert gas (15) from the first outlet passage (9i) to the hollow portion (9c) of the reaction vessel (9) through the first introduction passage (9d), the inner wall of the reaction vessel (9) It is characterized by diluting the raw material gas (3) passing between (9m) and the base (10).

  According to this, since the concentration of the source gas (3) passing through the gap between the inner wall (9m) of the reaction vessel (9) and the pedestal (10) is lowered, the inner wall (9m) of the reaction vessel (9) and the pedestal Supply of source gas (3) to (10) can be suppressed. For this reason, it is possible to suppress unnecessary silicon carbide polycrystals from adhering to the inner wall (9m) and the pedestal (10) of the reaction vessel (9) irrespective of the etching gas, and the gap that is the outlet of the source gas (3) Can be prevented.

  In the invention according to claim 2, the first outlet passage is based on one end face (9a) by pulling up the pedestal (10) by the shaft (11) in accordance with the growth of the silicon carbide single crystal (6). (9i) characterized in that the opening (9k) opened in the hollow portion (9c) of the reaction vessel (9) and the crystal surface (6a) of the silicon carbide single crystal (6) are arranged at the same height. To do.

  According to this, the growth rate of the silicon carbide polycrystal formed on the inner wall (9m) and the pedestal (10) of the reaction vessel (9) by the inert gas (15) can be minimized (see FIG. 5).

  In the invention according to claim 3, the first outlet is made with reference to one end face (9 a) by moving the pedestal (10) up and down on the shaft (11) in accordance with the growth of the silicon carbide single crystal (6). The opening (9k) opening in the hollow portion (9c) of the reaction vessel (9) in the passage (9i) and the crystal surface (6a) of the silicon carbide single crystal (6) are arranged at the same height. And

  According to this, even when the silicon carbide single crystal (6) is etched or grows in a concave shape, the crystal surface (6a) of the silicon carbide single crystal (6) can be made the same height. Moreover, the range which an inert gas (15) contacts can be enlarged by moving a base (10) up and down.

  In the invention according to claim 4, a plurality of first outlet passages (9 i) are provided in the side part (9 e) of the reaction vessel (9) along the central axis of the reaction vessel (9). An inert gas (15) is introduced into the hollow portion (9c) of the reaction vessel (9) from each of the outlet passages (9i).

  According to this, it can suppress that an unnecessary silicon carbide polycrystal is formed along the center axis | shaft of reaction container (9).

  In the invention according to claim 5, the pedestal (10) is pulled up by the shaft (11) in accordance with the growth of the silicon carbide single crystal (6), so that the plurality of first surfaces are based on the one end surface (9 a). In the first outlet passage (9i) located on the most end surface (9a) side of the outlet passage (9i), the opening (9k) opening to the hollow portion (9c) of the reaction vessel (9) and the silicon carbide single crystal The crystal surface (6a) of (6) is arranged at the same height.

  According to this, the growth rate of the silicon carbide polycrystal formed on the inner wall (9m) and the pedestal (10) of the reaction vessel (9) by the inert gas (15) can be minimized (see FIG. 5). Even if the pedestal (10) moves in accordance with the growth of the silicon carbide single crystal (6), the opening (9k) of another first outlet passage (9i) is located, so that the reaction vessel (9) The inert gas (15) can continue to be supplied to the gap between the inner wall (9m) and the pedestal (10). Therefore, the clogging of the gap can be suppressed, and the silicon carbide single crystal (6) can be continuously and elongated.

  In the invention according to claim 6, by moving the pedestal (10) up and down on the shaft (11) in accordance with the growth of the silicon carbide single crystal (6), a plurality of first surfaces are obtained with reference to one end surface (9a). In the first outlet passage (9i) located on the most end surface (9a) side of the one outlet passage (9i), the opening (9k) opening to the hollow portion (9c) of the reaction vessel (9) and the silicon carbide single-piece The crystal surface (6a) of the crystal (6) is arranged at the same height.

  According to this, even when the silicon carbide single crystal (6) is etched or grown into a concave shape, the first outlet passage located on the most end surface (9a) side among the plurality of first outlet passages (9i). The opening (9k) of (9i) and the crystal surface (6a) of the silicon carbide single crystal (6) can be made the same height. Moreover, the range which an inert gas (15) contacts can be enlarged by moving a base (10) up and down.

Moreover, in invention of Claim 1 , the connection part (9j) connected to the 1st introduction channel | path (9d) among 1st exit channel | paths (9i) is connected to reaction container ( The first outlet passage (9i) is inclined toward the central axis of the reaction vessel (9) by being positioned closer to one end face (9a) than the opening (9k) that opens to the hollow portion (9c) of 9) The inert gas (15) is introduced into the hollow portion (9c) in a state where the gas is discharged.

  According to this, the inert gas (15) can be easily flowed downstream of the raw material gas (3), so that the growth of the silicon carbide single crystal (6) is not hindered by the inert gas (15). be able to.

The invention according to claim 7 is characterized in that the pedestal (10) is rotated about the central axis of the reaction vessel (9).

  According to this, the inert gas (15) can be uniformly supplied to the gap between the inner wall (9m) of the reaction vessel (9) and the pedestal (10). For this reason, clogging of the entire gap can be prevented.

In the invention described in claim 8 , when the carrier gas includes the source gas (3) and flows into the hollow portion (9c) of the reaction vessel (9), the flow rate of the inert gas (15) is changed to the source gas ( The flow rate of the carrier gas containing 3) is more than the flow rate.

  As a result, the amount of the inert gas (15) passing through the gap between the inner wall (9m) of the reaction vessel (9) and the pedestal (10) is larger than the amount of the raw material gas (3). The source gas (3) can be sufficiently diluted with the gas (15).

According to the ninth aspect of the present invention, the pedestal (10) has a second introduction passage (10a) extending along the central axis of the reaction vessel (9), the second introduction passage (10a), and the reaction vessel (9). A second outlet passage (10b) connecting the hollow portion (9c) of the reaction vessel (9c) to the hollow portion (9c) of the reaction vessel (9) from the second outlet passage (10b) via the second introduction passage (10a). The raw material gas (3) passing between the inner wall (9m) of the reaction vessel (9) and the pedestal (10) is diluted by flowing an inert gas (15) through the reactor (9).

  According to this, since the inert gas (15) is introduced not only from the reaction vessel (9) but also from the pedestal (10) into the hollow portion (9c) of the reaction vessel (9), the inner wall (9m) of the reaction vessel (9) ) And pedestal (10) can be further suppressed from attaching silicon carbide polycrystal.

In the above, although the manufacturing method of the silicon carbide single crystal was described, the same can be said about the manufacturing apparatus for realizing the manufacturing method. That is, in the invention according to claim 10 , the reaction vessel (9) is provided on the outer periphery of the hollow portion (9c) of the reaction vessel (9) and extends along the central axis of the reaction vessel (9). A first outlet passage (9i) provided in the passage (9d) and the side portion (9e) of the reaction vessel (9) and connecting the first introduction passage (9d) and the hollow portion (9c) of the reaction vessel (9). ) And.

  The first outlet passage (9i) is connected to the connection portion (9j) connected to the first introduction passage (9d) in the first outlet passage (9i). 9) is positioned closer to one end face (9a) than the opening (9k) that opens to the hollow portion (9c), and is inclined toward the central axis of the reaction vessel (9) and the reaction vessel (9 ) Are provided along the central axis.

  Then, the inert gas (15) flows from the first outlet passage (9i) to the hollow portion (9c) of the reaction vessel (9) through the first introduction passage (9d), so that the inner wall of the reaction vessel (9) (9m) and the base gas (3) passing between the base (10) can be configured to be diluted.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is sectional drawing of the crystal growth apparatus of the silicon carbide single crystal which concerns on 1st Embodiment of this invention. (A) is the A section enlarged view of FIG. 1, (b) is the B section enlarged view of (a). It is CC sectional drawing of FIG. 2, DD sectional drawing, and EE sectional drawing. It is the figure which showed the raw material gas supply path | route in a crystal growth apparatus. It is a figure which shows the result of having investigated the flow velocity distribution in reaction container and the growth rate of a SiC polycrystal by simulation. It is sectional drawing of the reaction container which concerns on 2nd Embodiment of this invention. It is sectional drawing of the base which concerns on 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a silicon carbide single crystal crystal growth apparatus (manufacturing apparatus) according to the present embodiment. 2A is an enlarged view of a portion A in FIG. 1, and FIG. 2B is an enlarged view of a portion B in FIG. 2A. 3A is a sectional view taken along the line CC in FIG. 2, FIG. 3B is a sectional view taken along the line DD in FIG. 2, and FIG. 3C is a sectional view taken along the line EE in FIG.

  The crystal growth apparatus 1 shown in FIG. 1 supplies a SiC raw material gas 3 containing Si and C through an inlet 2 provided at the bottom, and discharges it through an outlet 4 provided at the top. An SiC single crystal 6 is grown on a seed crystal 5 made of an SiC single crystal substrate disposed in the growth apparatus 1.

  Such a crystal growth apparatus 1 includes a vacuum vessel 7, a first heat insulating material 8, a reaction vessel 9, a pedestal 10, a shaft 11, a second heat insulating material 12, a third heat insulating material 13, and a heating device 14. ing.

  The vacuum vessel 7 has a hollow cylindrical shape, can introduce argon gas (Ar) and the like, and accommodates other components of the crystal growth apparatus 1 and the internal space of the accommodating space. The pressure can be reduced by evacuating the pressure. An inlet 2 for the source gas 3 is provided at the bottom of the vacuum vessel 7, and an outlet 4 for the source gas 3 is provided at the top (specifically, above the side wall).

  The first heat insulating material 8 has a cylindrical shape such as a cylinder, and a raw material gas introduction pipe is constituted by the raw material gas introduction hole 8 a penetrating the first heat insulating material 8. The first heat insulating material 8 is made of, for example, felt carbon.

  The reaction vessel 9 is formed in a hollow cylindrical shape having a hollow portion 9c through which the raw material gas 3 flows from one end surface 9a side to the other end surface 9b side of the reaction vessel 9. In this embodiment, the reaction vessel 9 has a cylindrical shape with the same diameter, and is made of, for example, graphite. And seed crystal 5 is arranged in hollow part 9c which reaction container 9 constitutes, and SiC single crystal 6 is made to grow on the surface of seed crystal 5 in the hollow part 9c.

  Specific structures of the first heat insulating material 8 and the reaction vessel 9 will be described with reference to FIGS. 2 and 3.

  As shown in FIGS. 2 (a) and 3 (a), the first heat insulating material 8 has another through hole 8b provided in parallel to the source gas introduction hole 8a, and the inside of the through hole 8b. Is provided with an inert gas pipe 8c made of graphite, for example. One end side of the inert gas pipe 8 c is connected to the outside of the vacuum vessel 7.

  On the other hand, as shown in FIG. 2A, the reaction vessel 9 extends along the central axis of the reaction vessel 9 and extends in the circumferential direction of the central axis on the outer periphery of the hollow portion 9 c of the reaction vessel 9. An introduction passage 9d is provided. In the present embodiment, the first introduction passage 9 d is provided in the side portion 9 e of the reaction vessel 9.

  One end surface 9a of the reaction vessel 9 is opened in a ring shape, and the other end surface 9b is not opened. Accordingly, the first introduction passage 9d is closed on the other end surface 9b side of the reaction vessel 9, and is connected to the outside via the one end surface 9a. For this reason, one end face 9a of the reaction vessel 9 is arranged on the first heat insulating material 8 so that the hollow portion 9c of the reaction vessel 9 and the source gas introduction hole 8a of the first heat insulating material 8 are connected. The other end side of the inert gas pipe 8 c provided in the first heat insulating material 8 is connected to the first introduction passage 9 d of the reaction vessel 9.

  A gas reservoir 9f is provided in the first introduction passage 9d. This gas reservoir 9 f is a space formed by expanding a part of the first introduction passage 9 d in the radial direction of the reaction vessel 9.

  Further, the first introduction passage 9d of the reaction vessel 9 is provided with a gas stirring plate 9g located on the one end face 9a side of the reaction vessel 9 with respect to the gas reservoir 9f. As shown in FIG. 3 (b), the gas stirring plate 9g is a plate provided with a plurality of gas holes 9h penetrating at regular intervals. The gas introduction plate 9g divides the first introduction passage 9d into one end surface 9a side and the other end surface 9b side of the reaction vessel 9. That is, the gas reservoir 9f on the one end face 9a side of the reaction vessel 9 and the other end face 9b side are connected via a plurality of gas holes 9h.

  2A and 2B, the reaction vessel 9 is connected to the side portion 9e of the reaction vessel 9 with the first introduction passage 9d and the hollow portion 9c of the reaction vessel 9. A plurality of first outlet passages 9i are provided. As shown in FIG. 3C, the plurality of first outlet passages 9i are provided at regular intervals. In FIG. 3C, the SiC single crystal 6 is omitted.

  In the present embodiment, as shown in FIG. 2B, the connecting portion 9j connected to the first introduction passage 9d in the first outlet passage 9i is the hollow portion of the reaction vessel 9 in the first outlet passage 9i. It is located on one end face 9a side of the reaction vessel 9 with respect to the opening 9k opening in 9c. For this reason, the first outlet passage 9 i is inclined toward the central axis side of the reaction vessel 9. That is, the first outlet passage 9 i is a passage branched from the first introduction passage 9 d and is inclined with respect to the first introduction passage 9 d extending along the central axis of the reaction vessel 9.

  Furthermore, with reference to one end surface 9a, the opening 9k that opens to the hollow portion 9c of the reaction vessel 9 in the first outlet passage 9i and the crystal surface 6a of the SiC single crystal 6 are arranged at the same height. Here, the opening 9k of the first outlet passage 9i has a width in a direction parallel to the central axis of the reaction vessel 9, and the crystal surface 6a of the SiC single crystal 6 is not flat but is one end face of the reaction vessel 9. A curved surface is formed on the 9a side. For this reason, “the opening 9k and the crystal surface 6a are arranged at the same height” means that the opening 9k in the direction parallel to the central axis of the reaction vessel 9 is perpendicular to the central axis of the reaction vessel 9. It means that the crystal surface 6a is included in the range of the width.

  The inert gas pipe 8c, the first introduction passage 9d, and the first outlet passage 9i are used as passages for flowing an inert gas 15 such as argon (Ar) or helium (He). That is, as shown in FIG. 2A, the inert gas 15 introduced from the outside of the vacuum vessel 7 into the inert gas pipe 8c is introduced into the first introduction passage 9d through the inert gas pipe 8c. After that, the gas is once stored in the gas reservoir 9f, moves to the other end face 9b side of the reaction vessel 9 through the gas hole 9h of the gas stirring plate 9g, and passes through the first outlet passage 9i to the hollow portion of the reaction vessel 9 Introduced in 9c.

  As described above, the inert gas pipe 8c has a central axis of the reaction vessel 9 as shown in FIG. 3A with respect to the first introduction passage 9d provided in the circumferential direction of the central axis of the reaction vessel 9. Since it is not provided in the circumferential direction, the inert gas 15 introduced into the first introduction passage 9d from the inert gas pipe 8c is dispersed in the circumferential direction of the central axis of the reaction vessel 9, so that the inert gas is contained in the gas reservoir 9f. 15 is collected once.

  A pedestal 10 shown in FIG. 1 is a cylindrical member used for disposing the seed crystal 5 at the tip thereof, and is disposed in the hollow portion 9 c of the reaction vessel 9. The pedestal 10 is made of graphite, for example. The shape and dimensions of pedestal 10 are appropriately adjusted depending on the size of SiC single crystal 6 to be grown.

  The shaft 11 supports the pedestal 10 and is configured to pull up the pedestal 10 as the SiC single crystal 6 grows. That is, the shaft 11 is used as a support member for pulling up the pedestal 10 by a moving mechanism (not shown).

  The 2nd heat insulating material 12 is arrange | positioned along the side wall surface of the vacuum vessel 7, and has comprised the hollow cylinder shape. The second heat insulating material 12 substantially surrounds the first heat insulating material 8, the reaction vessel 9, and the like. The second heat insulating material 12 is made of felt carbon, for example.

  The 3rd heat insulating material 13 is for covering the part opened to the outflow port 4 side of the vacuum vessel 7 among the 2nd heat insulating materials 12, and has comprised plate shape. The third heat insulating material 13 is provided with a through hole 13a, and the shaft 11 is inserted into the through hole 13a. The third heat insulating material 13 is made of, for example, felt carbon.

  The heating device 14 is configured by, for example, an induction heating coil or a heater, and is disposed so as to surround the vacuum vessel 7. The heating device 14 is configured so that the temperature can be controlled along the central axis of the reaction vessel 9. For this reason, finer temperature control can be performed. The above is the overall configuration of the crystal growth apparatus 1 according to the present embodiment.

  Next, a method for manufacturing SiC single crystal 6 using the crystal growth apparatus 1 will be described with reference to FIG. First, as shown in FIG. 4, the seed crystal 5 is attached to the pedestal 10, and the pedestal 10 is positioned in the hollow portion 9 c of the reaction vessel 9 via the shaft 11. Subsequently, the vacuum chamber 7 is evacuated by evacuating the vacuum chamber 7 using an exhaust mechanism (not shown). Then, the heater is induction-heated by energizing the induction coil of the heating device 14, and the inside of the vacuum vessel 7 is heated by the radiant heat.

  In this case, for the portion where the source gas 3 is not desired to be recrystallized, for example, the temperature at which the sublimation rate is higher than the recrystallization rate of the source gas 3 (for example, about 2400 ° C.), the growth of the SiC single crystal 6 On the surface, a temperature at which the growth rate of the SiC single crystal 6 is higher than the sublimation rate (for example, about 2200 ° C.).

  Thereafter, the source gas 3 is contained in the carrier gas, and the source gas 3 is introduced into the vacuum vessel 7 from the inlet 2 of the vacuum vessel 7. As a result, as shown in FIG. 4, the source gas 3 is introduced into the hollow portion 9 c of the reaction vessel 9 through the source gas introduction hole 8 a of the first heat insulating material 8, and the other end from the one end surface 9 a of the reaction vessel 9 Flows to the end face 9b. Thereby, source gas 3 is supplied to seed crystal 5, and SiC single crystal 6 grows on seed crystal 5.

  Further, as the SiC single crystal 6 grows, the pedestal 10 is rotated by the shaft 11 about the central axis of the reaction vessel 9, and the one end surface 9 a of the reaction vessel 9 and the pedestal are aligned along the central axis of the reaction vessel 9. Keep away from 10. When the pedestal 10 is pulled up in this way, the opening 9k of the first outlet passage 9i and the crystal surface 6a of the SiC single crystal 6 are maintained at the same height with respect to one end face 9a of the reaction vessel 9.

  The source gas 3 that has not contributed to the growth of the SiC single crystal 6 passes through the gap between the inner wall 9 m of the reaction vessel 9 and the pedestal 10 and is discharged from the outlet 4 to the outside of the vacuum vessel 7.

  On the other hand, an inert gas 15 such as Ar is introduced into the inert gas pipe 8c. Thereby, as shown in FIG. 4, the inert gas 15 is introduced from the inert gas pipe 8c into the first introduction passage 9d of the reaction vessel 9, and is stored in the gas reservoir 9f. Then, the inert gas 15 passes uniformly through the plurality of gas holes 9h provided in the gas stirring plate 9g in the circumferential direction of the central axis of the reaction vessel 9, and further passes through the first introduction passage 9d to form a plurality of first gas. It is introduced into the hollow portion 9c of the reaction vessel 9 from the outlet passage 9i.

  In this way, when the inert gas 15 is introduced into the hollow portion 9c of the reaction vessel 9, in order to introduce the inert gas 15 uniformly in the circumferential direction of the central axis of the reaction vessel 9, the gas hole 9h is reacted. For example, eight or more locations are preferably provided in the circumferential direction of the central axis of the container 9. Similarly, the first outlet passage 9i is preferably provided with, for example, eight or more locations. Of course, it is desirable that the number of the gas holes 9h and the first outlet passages 9i be appropriately provided according to the size of the reaction vessel 9 and the crystal growth conditions of the SiC single crystal 6.

  In this way, the inert gas 15 flows from the first outlet passage 9i to the hollow portion 9c of the reaction vessel 9 through the first introduction passage 9d, thereby passing between the inner wall 9m of the reaction vessel 9 and the base 10. The source gas 3 that has not contributed to the growth of the SiC single crystal 6 is diluted. For this reason, the density | concentration of the raw material gas 3 which did not contribute to the growth of the SiC single crystal 6 falls, and recrystallization with respect to the inner wall 9m of the reaction container 9 or the side surface of the base 10 and adhesion of a SiC polycrystal are suppressed.

  The inventors set the hollow of the reaction vessel 9 when the opening 9k of the first outlet passage 9i and the crystal surface 6a of the SiC single crystal 6 are arranged at the same height with respect to one end face 9a of the reaction vessel 9. The gas flow velocity distribution in the portion 9c and the growth rate of the SiC polycrystal on the side surfaces of the SiC single crystal 6 and the pedestal 10 were examined by simulation. The result is shown in FIG.

  FIG. 5 shows a flow velocity distribution for a conventional product in which the first introduction passage 9d and the first outlet passage 9i are not provided in the left half of the reaction vessel 9 shown in FIG. 5, and the first introduction passage 9d and the first outlet passage 9i are shown in the right half. The flow velocity distribution of the product of the present invention provided with

  As shown in the flow velocity distribution of FIG. 5, in the product of the present invention, the inert gas 15 is introduced into the hollow portion 9 c of the reaction vessel 9 from the first outlet passage 9 i, so that the SiC single crystal 6 and the reaction vessel 9 A vortex is formed between the inner wall 9m. For this reason, the source gas 3 is easily diluted with the inert gas 15.

  As shown in the graph in the right column of FIG. 5, the growth rate of the SiC polycrystal on the side surfaces of the SiC single crystal 6 and the pedestal 10 is the highest in the conventional product. That is, in the conventional product, it is shown that the SiC polycrystal tends to adhere to the side surfaces of the SiC single crystal 6 and the pedestal 10. The same results were obtained for the inner wall 9m of the reaction vessel 9.

  On the other hand, in the product of the present invention, since the inert gas 15 is introduced into the hollow portion 9c of the reaction vessel 9, the growth rate is lower than the conventional one. That is, the source gas 3 is diluted by the inert gas 15 and is difficult to recrystallize.

  Further, in the graph in the right column of FIG. 5, “upper”, “same”, and “lower” of the product of the present invention indicate the positions of the opening 9 k of the first outlet passage 9 i and the crystal surface 6 a of the SiC single crystal 6. Showing the relationship. “Upper” means that the opening 9k is located on the other end face 9b side of the crystal surface 6a, and “lower” means that the opening 9k is located on the one end face 9a side of the crystal surface 6a. “Same” indicates that the opening 9k of the first outlet passage 9i and the crystal surface 6a of the SiC single crystal 6 are the same.

  The graph shows that the growth rate is the lowest when the opening 9k of the first outlet passage 9i and the crystal surface 6a of the SiC single crystal 6 have the same height. Therefore, by arranging the opening 9k of the first outlet passage 9i and the crystal surface 6a of the SiC single crystal 6 at the same height, the SiC single crystal 6 and the side surface of the pedestal 10 are hardly attached to the SiC polycrystal. can do.

  As described above, in this embodiment, by introducing the inert gas 15 from the outer periphery of the hollow portion 9c of the reaction vessel 9 into the hollow portion 9c, the gap between the inner wall 9m of the reaction vessel 9 and the pedestal 10 is reduced. It is characterized by diluting the raw material gas 3 that has not contributed to the growth that passes therethrough.

  Thereby, the density | concentration of the raw material gas 3 which passes the clearance gap between the inner wall 9m of the reaction container 9 and the base 10 can be lowered | hung. For this reason, supply of the source gas 3 to the inner wall 9m of the reaction vessel 9 and the pedestal 10 can be suppressed, and the SiC single crystal 6 and the SiC polycrystal can be prevented from adhering to the side surfaces of the pedestal 10. Therefore, clogging of the gap between the inner wall 9m of the reaction vessel 9 serving as the outlet of the raw material gas 3 and the pedestal 10 and SiC polycrystal falling to the bottom of the reaction vessel 9 to block the raw material gas 3 supply port. Since it can prevent, the SiC single crystal 6 can be made to grow continuously and long.

  Further, in the present embodiment, the pedestal is arranged such that the opening 9k of the first outlet passage 9i and the crystal surface 6a of the SiC single crystal 6 are arranged at the same height with respect to one end face 9a of the reaction vessel 9. 10 is raised. For this reason, the effect of diluting the source gas 3 with the inert gas 15 can be most enhanced, and the SiC polycrystal can be prevented from adhering to the side surfaces of the SiC single crystal 6 and the pedestal 10.

  When the pedestal 10 is pulled up, the pedestal 10 is rotated about the central axis of the reaction vessel 9, so that the inert gas 15 is concentrated at one place in the gap between the inner wall 9 m of the reaction vessel 9 and the pedestal 10. Can be prevented from being supplied. For this reason, the inert gas 15 can be uniformly supplied in the circumferential direction of the central axis of the reaction vessel 9, and adhesion of SiC polycrystal in the circumferential direction of the central axis of the reaction vessel 9 can be suppressed.

  Furthermore, in the present embodiment, the first outlet passage 9i is inclined toward the central axis side of the reaction vessel 9 with respect to the first introduction passage 9d. For this reason, the inert gas 15 can be introduced into the hollow portion 9 c of the reaction vessel 9 so that the inert gas 15 flows in the same direction as the flow direction of the source gas 3. Therefore, the inert gas 15 does not hinder the flow of the raw material gas 3, and the inert gas 15 easily flows downstream of the raw material gas 3, so that the inert gas 15 does not hinder the growth of the SiC single crystal 6. Can be.

(Second Embodiment)
In the present embodiment, parts different from the first embodiment will be mainly described. FIG. 6 is a view showing the reaction vessel 9 according to the present embodiment, and corresponds to an enlarged view of a part A in FIG.

  As shown in FIG. 6, in this embodiment, a plurality of first outlet passages 9 i are provided in the side portion 9 e of the reaction vessel 9 along the central axis of the reaction vessel 9. And the inert gas 15 is introduce | transduced into the hollow part 9c of the reaction container 9 from each 1st exit channel | path 9i provided in multiple steps.

  Further, when a plurality of first outlet passages 9 i are provided along the central axis of the reaction vessel 9, the most one of the first outlet passages 9 i of the plurality of steps with reference to one end surface 9 a of the reaction vessel 9. The opening 9k of the first outlet passage 9i located on the end face 9a side and the crystal surface 6a of the SiC single crystal 6 are arranged at the same height. This positional relationship is maintained by raising the pedestal 10 in accordance with the growth of the SiC single crystal 6.

  As described above, by providing the first outlet passage 9 i in a plurality of stages along the central axis of the reaction vessel 9, it is possible to suppress the SiC polycrystal from adhering along the central axis of the reaction vessel 9. Even if the pedestal 10 is pulled up in accordance with the growth of the SiC single crystal 6, the growth rate of the SiC polycrystal can be kept low because the opening 9k of the other first outlet passage 9i is provided.

(Third embodiment)
In the present embodiment, parts different from the first and second embodiments will be mainly described. FIG. 7 is a cross-sectional view of the base 10 according to the present embodiment. As shown in this figure, the pedestal 10 has a second introduction passage 10 a extending along the central axis of the reaction vessel 9 and a second outlet connecting the second introduction passage 10 a and the hollow portion 9 c of the reaction vessel 9. And a passage 10b.

  According to this, since the inert gas 15 flows from the second outlet passage 10b to the hollow portion 9c of the reaction vessel 9 through the second introduction passage 10a, the raw material that passes between the inner wall 9m of the reaction vessel 9 and the base 10 is passed. The gas 3 can be diluted more effectively. For this reason, adhesion of SiC polycrystal to the inner wall 9m of the reaction vessel 9 or the pedestal 10 can be further suppressed.

(Other embodiments)
The specific structure of the crystal growth apparatus 1 shown in the above embodiments is merely an example, and the shape, material, and the like can be changed as appropriate. For example, the reaction vessel 9 has a hollow cylindrical shape, but may have a bottomed cylindrical shape. Further, although the first introduction passage 9d is provided in the side portion 9e of the reaction vessel 9, for example, a gap between the outer wall of the reaction vessel 9 and the second heat insulating material 12 may be used as the first introduction passage 9d. In this case, it is only necessary to provide the reaction vessel 9 with the first outlet passage 9i.

  In each of the above embodiments, the source gas 3 is introduced into the inside of the vacuum vessel 7 by including the source gas 3 in the carrier gas, but by defining the flow rate of the carrier gas and the flow rate of the inert gas 15, The effect of dilution of the source gas 3 can be further enhanced. Specifically, the flow rate of the inert gas 15 is set to be equal to or higher than the flow rate of the carrier gas including the source gas 3. Thereby, since the quantity of the inert gas 15 which passes through the clearance gap between the inner wall 9m of the reaction container 9 and the base 10 becomes larger than the quantity of the raw material gas 3, the raw material gas 3 can fully be diluted.

  In each of the above embodiments, the pedestal 10 is pulled up by the shaft 11 in accordance with the growth of the SiC single crystal 6, so that the opening 9 k of the first outlet passage 9 i and the SiC single crystal 6 are based on one end face 9 a. The crystal surface 6a was arranged at the same height. Similarly, even when the first outlet passage 9i is provided in a plurality of stages, the opening of the first outlet passage 9i located on the most end surface 9a side among the plurality of first outlet passages 9i with reference to the one end surface 9a. The portion 9k and the crystal surface 6a of the SiC single crystal 6 are arranged at the same height. However, this is an example in which the pedestal 10 is moved by the shaft 11, and the pedestal 10 may be moved up and down by the shaft 11 in accordance with the growth of the SiC single crystal 6. Thereby, even when SiC single crystal 6 is etched or grows in a concave shape, opening 9k of first outlet passage 9i and crystal surface 6a of SiC single crystal 6 can be arranged at the same height. Moreover, the range which the inert gas 15 contacts can also be enlarged by moving the base 10 up and down.

DESCRIPTION OF SYMBOLS 1 Crystal growth apparatus 3 Source gas 5 Seed crystal 6 SiC single crystal 6a Crystal surface 9 Reaction vessel 9a, 9b End surface of reaction vessel 9c Hollow part of reaction vessel 9d First introduction passage 9e Side part of reaction vessel 9i First exit passage 9j Connection part 9k Opening part 9m Inner wall of reaction vessel 10 Base 15 Inert gas

Claims (10)

A seed crystal (5) composed of a silicon carbide single crystal substrate is placed on a pedestal (10) placed in a hollow portion (9c) of a hollow cylindrical reaction vessel (9), and a silicon carbide source gas A silicon carbide single crystal (6) is grown on the surface of the seed crystal (5) by supplying (3) from one end surface (9a) side of the reaction vessel (9) to the other end surface (9b) side. In the manufacturing method of the silicon carbide single crystal to be made,
A first introduction passage (9d) extending along the central axis of the reaction vessel (9) is provided on the outer periphery of the hollow portion (9c) of the reaction vessel (9), and a side portion (9e) of the reaction vessel (9) is provided. ) Is provided with a first outlet passage (9i) that connects the first introduction passage (9d) and the hollow portion (9c) of the reaction vessel (9),
By flowing an inert gas (15) from the first outlet passage (9i) to the hollow portion (9c) of the reaction vessel (9) through the first introduction passage (9d), the reaction vessel (9) A raw material gas (3) passing between the inner wall (9m) and the pedestal (10) of the silicon carbide single crystal,
The connecting portion (9j) connected to the first introduction passage (9d) in the first outlet passage (9i) is connected to the hollow portion (9c) of the reaction vessel (9) in the first outlet passage (9i). ), The first outlet passage (9i) is inclined toward the central axis of the reaction vessel (9). A process for producing a silicon carbide single crystal, wherein an inert gas (15) is introduced into the hollow portion (9c) .   By pulling up the pedestal (10) by the shaft (11) in accordance with the growth of the silicon carbide single crystal (6), the first outlet passage (9i) The opening (9k) opening in the hollow portion (9c) of the reaction vessel (9) and the crystal surface (6a) of the silicon carbide single crystal (6) are arranged at the same height. 2. A method for producing a silicon carbide single crystal according to 1.   The pedestal (10) is moved up and down by the shaft (11) in accordance with the growth of the silicon carbide single crystal (6), so that the first outlet passage (9i) can be formed on the basis of the one end surface (9a). Of these, the opening (9k) opened in the hollow portion (9c) of the reaction vessel (9) and the crystal surface (6a) of the silicon carbide single crystal (6) are arranged at the same height. Item 2. A method for producing a silicon carbide single crystal according to Item 1.   A plurality of stages of the first outlet passages (9i) are provided in the side portion (9e) of the reaction container (9) along the central axis of the reaction container (9), and the first outlet passages (9i) of the plurality of stages are provided. The method for producing a silicon carbide single crystal according to claim 1, wherein the inert gas (15) is introduced from each into the hollow portion (9c) of the reaction vessel (9).   By pulling up the pedestal (10) with the shaft (11) in accordance with the growth of the silicon carbide single crystal (6), the plurality of first outlet passages (9i) with the one end face (9a) as a reference. Of the first outlet passage (9i) located closest to the one end surface (9a), the opening (9k) that opens to the hollow portion (9c) of the reaction vessel (9) and the silicon carbide single crystal (6 The method for producing a silicon carbide single crystal according to claim 4, wherein the crystal surface (6a) is disposed at the same height.   By moving the pedestal (10) up and down by the shaft (11) in accordance with the growth of the silicon carbide single crystal (6), the plurality of first outlet passages (9i) with the one end surface (9a) as a reference. ) In the first outlet passage (9i) located closest to the one end face (9a) side, the opening (9k) opening in the hollow portion (9c) of the reaction vessel (9) and the silicon carbide single crystal ( The method for producing a silicon carbide single crystal according to claim 4, wherein the crystal surface (6a) of 6) is arranged at the same height. The method for producing a silicon carbide single crystal according to any one of claims 1 to 6 , wherein the pedestal (10) is rotated about a central axis of the reaction vessel (9). When the carrier gas contains the source gas (3) and flows into the hollow portion (9c) of the reaction vessel (9), the flow rate of the inert gas (15) is adjusted to include the source gas (3). The method for producing a silicon carbide single crystal according to any one of claims 1 to 7 , wherein the flow rate is equal to or higher than a flow rate of the carrier gas. The pedestal (10) has a second introduction passage (10a) extending along the central axis of the reaction vessel (9), the second introduction passage (10a), and a hollow portion (9c) of the reaction vessel (9). A second outlet passage (10b) connecting the
By flowing the inert gas (15) from the second outlet passage (10b) to the hollow portion (9c) of the reaction vessel (9) through the second introduction passage (10a), the reaction vessel (9 The raw material gas (3) passing between the inner wall (9m) and the pedestal (10) is diluted, and the production of the silicon carbide single crystal according to any one of claims 1 to 8 Method. A seed crystal (5) composed of a silicon carbide single crystal substrate is placed on a pedestal (10) placed in a hollow portion (9c) of a hollow cylindrical reaction vessel (9), and a silicon carbide source gas A silicon carbide single crystal (6) is grown on the surface of the seed crystal (5) by supplying (3) from one end surface (9a) side of the reaction vessel (9) to the other end surface (9b) side. An apparatus for producing a silicon carbide single crystal,
The reaction vessel (9) is provided on the outer periphery of the hollow portion (9c) of the reaction vessel (9), and extends along the central axis of the reaction vessel (9), and the reaction A first outlet passage (9i) provided on the side (9e) of the vessel (9) and connecting the first introduction passage (9d) and the hollow portion (9c) of the reaction vessel (9). And
In the first outlet passage (9i), the connecting portion (9j) connected to the first introduction passage (9d) in the first outlet passage (9i) is connected to the first outlet passage (9i) in the first outlet passage (9i). The reaction vessel (9) is inclined toward the central axis side of the reaction vessel (9) by being positioned on the one end surface (9a) side of the opening (9k) opening in the hollow portion (9c) of the reaction vessel (9). Are provided along the central axis of the reaction vessel (9),
An inert gas (15) flows from the first outlet passage (9i) to the hollow portion (9c) of the reaction vessel (9) through the first introduction passage (9d), thereby the reaction vessel (9). The raw material gas (3) which passes between the inner wall (9m) and the said base (10) is diluted, The manufacturing apparatus of the silicon carbide single crystal characterized by the above-mentioned.