JP2018168010A - Silicon carbide crystal manufacturing device, and method of manufacturing silicon carbide single crystal using the same - Google Patents

Abstract

To provide an SiC single-crystal manufacturing device that facilitates reuse even if SiC is recrystallized at a bottom part.SOLUTION: A silicon carbide single-crystal manufacturing device comprises: a crucible 1 having a container body 1a and a lid material 1b closing one face as an opening part of the container body 1a; and a heating device 5 which heats a cylindrical outer peripheral wall to heat the crucible 1, the silicon carbide single-crystal manufacturing device being characterized in that the container body 1a is filled with a silicon carbide raw material 4, a silicon carbide single-crystal substrate 2 as a seed crystal is arranged for the lid material 1b, and the crucible 1 is heated by the heating device 5 to sublime the silicon carbide raw material 4 for growth of a silicon carbide single crystal 3 on a surface of the silicon carbide single-crystal substrate 2. The crucible 1 has an underlay member 1c which is arranged on a bottom part of the container body 1a to cover at least a center part of the bottom part, and also configured to be removed from the container body 1a. Even if SiC6 is recrystallized on the lower-part member 1c, it can be recovered together with the lower-part member 1c.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a silicon carbide (hereinafter referred to as SiC) single crystal manufacturing apparatus and a method for manufacturing a SiC single crystal using the same.

  Conventionally, as an SiC single crystal manufacturing method for growing an SiC single crystal on a seed crystal, for example, crystal growth of an SiC single crystal by a sublimation recrystallization method is known. In the sublimation recrystallization method, a SiC raw material for sublimation is placed in a graphite crucible having a bottomed cylindrical container body and a lid, and the sublimation gas of the SiC raw material generated by heating with a heating device is covered with the lid. The SiC single crystal is grown on the surface of the seed crystal.

  In such a sublimation recrystallization method, since the SiC raw material is heated by heating the outer peripheral wall of the crucible with an induction heating coil arranged on the outer peripheral side of the crucible, a comparison is made near the center of the bottom of the crucible. The target temperature is lowered and SiC is easily recrystallized. In recent years, it has been desired to reuse the crucible, but it is difficult to remove SiC recrystallized at the bottom, and the crucible will break if it is forcibly removed. For this reason, it becomes difficult to reuse the crucible.

  For this reason, as a means for suppressing recrystallization of SiC, Patent Document 1 proposes a structure including a heat insulating layer for suppressing heat dissipation from the bottom at the bottom of the crucible. As the heat insulating layer, for example, porous carbon or carbon felt in which a plurality of holes are formed is used, and the heat conductivity of the heat insulating layer is set to 0.06 W / m · k or less and low heat conductivity. By disposing such a heat insulating layer at the bottom of the crucible, the temperature reduction of the bottom of the crucible is suppressed, so that recrystallization of SiC is suppressed.

  In addition, the bottom part of the crucible is made of a material having high electrical conductivity so that it can be heated more easily, or the outer peripheral wall of the crucible is extended below the bottom part so that the part that is heated by induction becomes wider. Has also been proposed.

JP 2010-76990 A

  However, as the SiC single crystal increases in diameter, the crucible increases in size, and it is difficult to prevent recrystallization of SiC even if the heat insulating layer is disposed at the bottom of the crucible as in Patent Document 1. In addition, when the bottom part of the crucible is made of a material having high electrical conductivity, and the structure in which the outer peripheral wall of the crucible extends below the bottom part, there are problems similar to the structure of Patent Document 1.

  An object of the present invention is to provide a SiC single crystal manufacturing apparatus that can be easily reused even when SiC is recrystallized at the bottom, and a method of manufacturing a SiC single crystal using the same. And

  In order to achieve the above object, the SiC single crystal manufacturing apparatus according to claim 1 has an opening on one side, a bottom on the other side opposite to the one side, and a cylindrical outer peripheral wall. A crucible (1) having a container body (1a) composed of a bottomed cylindrical member having a hollow inside, a lid member (1b) for closing one surface of the container body, and heating the outer peripheral wall And a heating device (5) for heating the crucible, and the silicon carbide raw material (4) is filled in the container body, and the silicon carbide single crystal substrate (2) serving as a seed crystal for the lid material The silicon carbide single crystal (3) is grown on the surface of the silicon carbide single crystal substrate by heating the crucible with a heating device and sublimating the silicon carbide raw material. In such a configuration, the crucible is provided with an underlay member (1c) that is disposed on the bottom of the container body, covers at least the center of the bottom, and is configured to be removable from the container body.

  Thus, it is set as the structure which arrange | positioned the base material to the bottom part of the container main body. For this reason, when removing recrystallized SiC, by removing together with the underlay member, portions other than the underlay member of the crucible can be reused. Therefore, even if SiC is recrystallized at the bottom of the crucible, a SiC single crystal manufacturing apparatus that can be easily reused can be obtained.

  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 concerning 1st Embodiment. It is sectional drawing of the SiC single crystal manufacturing apparatus concerning 2nd Embodiment. It is sectional drawing of the SiC single crystal manufacturing apparatus concerning 3rd Embodiment. It is sectional drawing of the SiC single crystal manufacturing apparatus concerning 4th Embodiment. It is sectional drawing of the SiC single crystal manufacturing apparatus concerning 5th Embodiment. It is sectional drawing of the SiC single crystal manufacturing apparatus concerning 6th Embodiment.

  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)
An SiC single crystal growth apparatus according to the first embodiment and a method for producing an SiC single crystal using the same will be described with reference to FIG.

  The SiC single crystal manufacturing apparatus shown in FIG. 1 is an apparatus that realizes SiC single crystal growth by a sublimation recrystallization method. This SiC single crystal manufacturing apparatus is provided with a graphite crucible 1 constituted by a container body 1a, a circular lid 1b, and an underlay member 1c.

  The container body 1a is composed of a bottomed cylindrical member having an open side on one side, a bottom side on the other side opposite to the one side, a cylindrical outer peripheral wall, and a hollow part on the inside. Has been. The container main body 1a is made of graphite and has a heat transfer coefficient of 50 to 150 W / m · k.

  The lid member 1b is a member that closes one side of the container body 1a that opens, and is formed into a disk shape. The lid member 1b is made of graphite of the same material as the container body 1a, so that the heat transfer coefficient is the same as that of the container body 1a. ing. A SiC single crystal substrate 2 serving as a seed crystal is bonded to the center of the back surface of the lid member 1b via an adhesive (not shown) or the like, and an SiC single crystal 3 is grown on the SiC single crystal substrate 2. Note that lid 1b may be formed of a simple disk-shaped member, but a pedestal may be formed by projecting a central portion where SiC single crystal substrate 2 is disposed downward.

The underlay member 1c is a disc-like member, and is disposed at the bottom of the container body 1a and is disposed so as to cover at least the center of the bottom. The constituent material of the underlay member 1c is made of graphite having a heat transfer coefficient equal to or higher than that of the container body 1a.
The underlay member 1c is only placed on the bottom of the container body 1a, and is not fixed to the container body 1a with an adhesive or the like, and is removable from the container body 1a. It is configured.

  The SiC raw material 4 is filled in the hollow part of the container main body 1a in the crucible 1 configured as described above, more specifically, on the bottom part of the container main body 1a and the underlying member 1c. As the SiC raw material 4, SiC in powder form is used.

  And the heating apparatus 5 comprised by the induction heating coil etc. is arrange | positioned on the outer periphery of the crucible 1, The outer peripheral wall of the container main body 1a in the crucible 1 is mainly heated by the induction heating by the heating apparatus 5, and the SiC raw material 4 Can be sublimated by heating. In FIG. 1, the heating device 5 is provided only at a position corresponding to the SiC raw material 4 in the crucible 1, but may be provided at a position corresponding to the growth space of the SiC single crystal 3. In the case of such a configuration, each part of the heating device 5 is configured to be able to independently adjust the heating temperature, and can be controlled so that the temperature of the growth surface of the SiC single crystal 3 is lower than the SiC raw material 4 by a predetermined temperature. Is done.

  Here, although the dimensions of the respective parts constituting the crucible 1 are arbitrary, the distance from the side wall surface of the container body 1a to the underlay member 1c is larger than the maximum particle size of the powdered SiC raw material 4. . Specifically, assuming that the diameter of the underlaying member 1c is D1, the inner diameter of the container body 1a is D2, and the maximum particle diameter of the SiC raw material 4 is D3, the dimensional relationship satisfies the relationship of D1 <D2-D3 × 2. The lower limit value of the diameter D1 of the underlay member 1c is a value determined according to the value of the inner diameter D2 of the container body 1a. The larger the inner diameter D2, the larger the lower limit value of the diameter D1. That is, the underlaying member 1c only needs to be formed so as to cover at least a region where SiC6 is recrystallized and deposited, and the region where SiC6 is recrystallized and precipitated is assumed to have a constant power of the heating device 5 It is determined by the distance from the wall surface of the container body 1a. For this reason, the diameter D1 of the underlay member 1c is increased as the inner diameter D2 is increased.

  On the other hand, the diameter D1 of the underlay member 1c is preferably smaller than the inner diameter D2 of the container main body 1a so that it can be easily removed from the container main body 1a. However, if the difference between the diameter D1 and the inner diameter D2 is small, that is, if the gap between the container main body 1a and the underlay member 1c is narrow, the residue of the SiC raw material 4 is caught between them, and the underlay member 1c is removed from the container main body. It becomes difficult to remove from 1a. For this reason, it is preferable to satisfy the relationship of D1 <D2-D3 × 2.

  Although not shown, the crucible 1 is accommodated in a vacuum container such as a quartz container and placed on a rotating device. And while introducing inert gas, such as Ar, hydrogen gas, etc. in a vacuum vessel, the crucible 1 is rotated with a rotating device, and the crucible 1 is induction-heated with a heating device 5, whereby the SiC single crystal 3 Crystal growth is performed.

  As described above, the SiC single crystal manufacturing apparatus according to the present embodiment is configured. Then, the manufacturing method of the SiC single crystal 3 using the SiC single crystal manufacturing apparatus comprised in this way is demonstrated.

  First, after placing the underlay member 1c on the bottom of the container body 1a, the SiC raw material 4 is filled on the bottom of the container body 1a and the underlay member 1c. Moreover, after affixing the SiC single crystal substrate 2 used as a seed crystal to the back surface side of the lid | cover material 1b, the lid | cover material 1b is installed in the container main body 1a. Then, an inert gas or the like in a growth atmosphere is introduced into a vacuum container (not shown), and a gas serving as a dopant source, for example, a nitrogen gas serving as a nitrogen source is introduced as necessary. By controlling the power of the heating device 5 in this state, the temperature in the vicinity of the SiC raw material 4 becomes equal to or higher than the sublimation temperature of the SiC raw material 4, and the temperature in the vicinity of the SiC single crystal substrate 2 serving as a seed crystal is higher than that. A heating process is performed so that the temperature is reduced to about 10 ° C to 200 ° C. Further, by rotating the crucible 1 with a rotating device, heating unevenness is suppressed so that the temperature distribution is uniform with respect to the central axis of the crucible 1. Under such conditions, for example, a SiC single crystal 3 doped with nitrogen is grown. And after growing the SiC single crystal 3, after performing the process of cooling the SiC single crystal 3 with the crucible 1, the removal process of the cover material 1b and the SiC single crystal 3 is performed, or the residue of the SiC raw material 4 is removed. The process of removing is performed and the crucible 1 is made into a reusable state.

  At this time, during the growth of the SiC single crystal 3, that is, during the heating process, the temperature becomes lower than the outer peripheral wall side in the vicinity of the center of the bottom of the container body 1 a that is far from the heating device 5. Thereby, a part of SiC raw material 4 recrystallizes SiC6. However, since the underlay member 1c is disposed on the bottom of the container main body 1a, a step of recrystallizing SiC6 on the underlay member 1c can be performed.

  In this manner, SiC 6 can be selectively recrystallized on the underlying member 1c. Therefore, it is possible to easily remove SiC6 by performing the step of removing the recrystallized SiC6 together with the underlaying member 1c simultaneously with or after the step of removing the residue of the SiC raw material 4. It becomes. If the new underlay member 1c is arranged at the bottom of the container body 1a, the container body 1a and the lid member 1b can be used as they are, so that the crucible 1 can be reused.

  As described above, the SiC single crystal manufacturing apparatus according to the present embodiment has a structure in which the underlay member 1c is disposed at the bottom of the container body 1a. For this reason, when removing the recrystallized SiC 6 together with the underlay member 1c, a portion other than the underlay member 1c in the crucible 1 can be reused. Therefore, even if SiC is recrystallized at the bottom of the crucible 1, a SiC single crystal manufacturing apparatus that can be easily reused can be obtained.

(Second Embodiment)
A second embodiment will be described. In the present embodiment, the structure of the container main body 1a is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, differences from the first embodiment will be mainly described.

  As shown in FIG. 2, in this embodiment, the recessed part 1d is formed in the bottom part of the container main body 1a, and the underlaying member 1c is engage | inserted in this recessed part 1d. Specifically, the recess 1d is formed in a shape and size corresponding to the underlay member 1c. For this reason, when the underlay member 1c is fitted in the recess 1d, the end surface of the underlay member 1c and the side surface of the recess 1d are opposed to each other, preferably in contact with each other, and other than the recess 1d in the bottom of the container body 1a. The upper surface of the portion and the upper surface of the underlying member 1c are substantially flush.

  Thus, you may make it form the recessed part 1d which fits the base material 1c in the bottom part of the container main body 1a. Even with such a structure, it is possible to obtain the same effect as in the first embodiment, and it is difficult for the residue of the SiC raw material 4 to adhere to the end face of the underlaying member 1c, and it is more selective near the center of the bottom of the container body 1a. In addition, SiC6 can be easily recrystallized.

(Third embodiment)
A third embodiment will be described. In the present embodiment, the structure of the container main body 1a is changed with respect to the second embodiment, and the other parts are the same as those in the second embodiment. Therefore, differences from the first embodiment will be mainly described.

  As shown in FIG. 3, in the present embodiment, a recess 1d is formed in the bottom of the container body 1a, and the underlay member 1c is fitted into the recess 1d, while the bottom of the container body 1a is other than the recess 1d. The upper surface of the portion is positioned higher than the upper surface of the underlay member 1c. That is, the depth of the concave portion 1d is made larger than the thickness of the underlying member 1c.

Even with such a structure, the same effects as those of the second embodiment can be obtained, and the height of the upper surface of the underlaying member 1c is lower than the upper surface of the bottom portion of the container body 1a other than the concave portion 1d. As a result, it becomes easier for the underlay member 1c to be lowered in temperature. For this reason, SiC6 can be easily recrystallized selectively near the center of the bottom of the container body 1a.

(Fourth embodiment)
A fourth embodiment will be described. In this embodiment, the structure of the underlaying member 1c is changed with respect to the second and third embodiments, and the other parts are the same as those of the second and third embodiments, and therefore the second and third embodiments. The differences will be mainly described. Here, the case where the structure of the present embodiment is applied to the configuration of the second embodiment will be described as an example, but the present embodiment can also be applied to the structure of the third embodiment.

  As shown in FIG. 4, in the present embodiment, a recess 1e is formed at the center position of the underlay member 1c, that is, at the portion corresponding to the center position of the bottom of the container body 1a. That is, the center position of the underlay member 1c is set lower than the upper surface of the bottom portion of the container body 1a other than the recess 1d.

Even with such a structure, the same effect as in the second and third embodiments can be obtained, and the upper surface of the recessed portion 1e is higher than the upper surface of the bottom portion of the container body 1a other than the recessed portion 1d. Therefore, the temperature of the underlaying member 1c is easily lowered in the recessed portion 1e. For this reason, SiC6 can be easily recrystallized selectively near the center of the bottom of the container body 1a.

(Fifth embodiment)
A fifth embodiment will be described. The present embodiment is different from the first to fourth embodiments in that the underlaying member 1c is provided with a detaching mechanism, and the other parts are the same as the first to fourth embodiments, and thus the first to fourth embodiments. The part different from the form will be mainly described. Here, the case where the structure of the present embodiment is applied to the configuration of the first embodiment will be described as an example, but the present invention can also be applied to the structures of the second to fourth embodiments.

  As shown in FIG. 5, in this embodiment, a bar-shaped member 1f extending to the lid 1b side, that is, upward is attached to the center position of the underlay member 1c. The bar-shaped member 1f is made of the same material as the underlay member 1c. The height of the rod-shaped member 1 f is preferably set to a height that is higher than the filling height of the SiC raw material 4 and does not affect the growth of the SiC single crystal 3.

  Thus, by attaching the rod-like member 1f to the underlay member 1c, it is possible to remove the underlay member 1c using the rod-like member 1f as a removal mechanism after the SiC single crystal 3 is manufactured. Thereby, while being able to acquire the same effect as 1st-4th embodiment, it becomes possible to make removal of the base material 1c easy.

(Sixth embodiment)
A sixth embodiment will be described. The present embodiment is provided with a mechanism for removing the underlay member 1c with respect to the first to fifth embodiments, and is otherwise the same as the first to fifth embodiments, so the first to fifth embodiments. The part different from the form will be mainly described. Here, the case where the structure of the present embodiment is applied to the configuration of the first embodiment will be described as an example, but the present invention can also be applied to the structures of the second to fifth embodiments.

  As shown in FIG. 6, in this embodiment, an opening 1g is formed at the center of the bottom of the container body 1a. By using such an opening 1g as a detaching mechanism and pushing out the underlying member 1c through the opening 1g, the underlying member 1c can be easily removed.

  Thus, by forming the opening 1g at the bottom of the container body 1a, it is possible to remove the underlay member 1c using the opening 1g as a detaching mechanism after the SiC single crystal 3 is manufactured. Thereby, while being able to acquire the effect similar to 1st-5th embodiment, it becomes possible to make removal of the base material 1c easy.

(Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

  For example, in each of the above embodiments, an example of the structure of the crucible 1 has been shown. However, the structure shown in each of the above embodiments only shows the main structure of the crucible 1 and may have other structures. For example, the container body 1a may be divided into a plurality of structures, or the lid member 1b may be provided with a guide wall extending in the growth direction of the SiC single crystal 3. Further, the shape of the underlay member 1c is not limited to a disk shape, but may be other shapes such as a polygonal plate shape.

  Further, the bar-shaped member 1f described in the fifth embodiment is formed at the center position of the underlay member 1c, and the opening 1g described in the sixth embodiment is also formed at the center position of the bottom of the container body 1a. Yes. However, this is only an example, and it may be formed in another place. However, in consideration of the symmetry of the temperature distribution during heating, it is preferable that the bar-shaped member 1f and the opening 1g are formed in a place as in the fifth and sixth embodiments.

  Moreover, although the crucible 1 is made of graphite, it may be made of other materials, and all of them need not be made of graphite. For example, it may be partially coated with a refractory metal.

DESCRIPTION OF SYMBOLS 1 Crucible 1a Container main body 1b Cover material 1c Underlay member 1d Recess 1e Recess 2 SiC single crystal substrate 3 SiC single crystal 4 SiC raw material 5 Heating device

Claims (9)

A container body composed of a bottomed cylindrical member having an opening on one side, a bottom side on the other side opposite to the one side, a cylindrical outer peripheral wall, and a hollow inside. A crucible (1) having (1a) and a lid member (1b) for closing the one surface of the container body;
A heating device (5) for heating the crucible by heating the outer peripheral wall,
The container body is filled with a silicon carbide raw material (4), and a silicon carbide single crystal substrate (2) serving as a seed crystal is disposed with respect to the lid member, and the crucible is heated by the heating device to perform the carbonization. A silicon carbide single crystal manufacturing apparatus for growing a silicon carbide single crystal (3) on a surface of the silicon carbide single crystal substrate by sublimating a silicon raw material,
The crucible is disposed on the bottom of the container body, covers at least the center of the bottom, and has an underlay member (1c) configured to be removable from the container body. manufacturing device. The underlay member is configured in a disc shape,
The silicon carbide raw material is powdered silicon carbide,
2. The carbonization according to claim 1, wherein D1 <D2−D3 × 2 is established, where D1 is a diameter of the underlay member, D2 is an inner diameter of the container body, and D3 is a particle diameter of the silicon carbide raw material. Silicon single crystal manufacturing equipment.   A concave portion (1d) is formed in the bottom portion of the container main body, the underlay member is fitted in the concave portion, and an upper surface of the underlay member is a portion of the bottom portion of the container main body other than the concave portion. The silicon carbide single crystal manufacturing apparatus according to claim 1 or 2, wherein the height is equal to or lower than a height of an upper surface of the silicon carbide.   The underlay member is formed with a recess (1e) at the center position of the underlay member, wherein the upper surface of the underlay member is the upper surface of the bottom portion of the container body other than the recess. The silicon carbide single crystal manufacturing apparatus according to claim 3, wherein the apparatus is lower than the height of the silicon carbide single crystal.   The silicon carbide single crystal manufacturing apparatus according to any one of claims 1 to 4, wherein the underlay member is provided with a rod-like member (1f) extending upward from the underlay member.   The silicon carbide single crystal manufacturing apparatus according to any one of claims 1 to 5, wherein an opening (1g) is formed in a part of the bottom portion of the container body where the underlay member is disposed. A container body composed of a bottomed cylindrical member having an opening on one side, a bottom side on the other side opposite to the one side, a cylindrical outer peripheral wall, and a hollow inside. A crucible (1) having (1a) and a lid member (1b) for closing the one surface of the container body;
Using a silicon carbide single crystal manufacturing apparatus provided with a heating device (5) for heating the crucible by heating the outer peripheral wall,
The container body is filled with a silicon carbide raw material (4), and a silicon carbide single crystal substrate (2) serving as a seed crystal is disposed with respect to the lid member, and the crucible is heated by the heating device to perform the carbonization. A method for producing a silicon carbide single crystal in which a silicon carbide single crystal (3) is grown on a surface of the silicon carbide single crystal substrate by sublimating a silicon raw material,
Disposing an underlay member (1c) that covers at least a central portion of the bottom portion and is configured to be removable from the container body, on the bottom portion of the container body;
After placing the underlay member, filling the silicon carbide raw material on the bottom and the underlay member in the container body;
Sublimating the silicon carbide raw material by heating the crucible with the heating device, and growing the silicon carbide single crystal on the surface of the silicon carbide single crystal substrate;
After the growth of the silicon carbide single crystal, the silicon carbide single crystal and the lid member are removed from the container body, and the silicon carbide raw material residue is removed, and the underlay member is removed during the growth of the silicon carbide single crystal. Removing the underlay member from the container body together with silicon carbide (6) recrystallized above, to produce a silicon carbide single crystal.   8. The silicon carbide single crystal according to claim 7, wherein the silicon carbide single crystal is selectively recrystallized on the underlay member in a center portion of the bottom portion of the container body in growing the silicon carbide single crystal. Manufacturing method.   The method for producing a silicon carbide single crystal according to claim 7 or 8, wherein in removing the underlay member from the container body, the residue of the silicon carbide raw material is simultaneously removed.

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