SiC single crystal growth equipment

Abstract

To provide a SiC single crystal growth apparatus capable of sublimating a solid raw material by uniformly heating to produce a gas raw material and reducing a waste of a raw material in growing the SiC single crystal.SOLUTION: A SiC single crystal growth apparatus 1 includes: a raw material accommodating part 12 for accommodating a solid raw material M(s) composed of SiC in a part of an internal space S partitioned by a cylindrical side peripheral part 14; a heating container 10 having a seed crystal attaching part 16 in which a SiC seed crystal 2 is arranged in an internal space S side where the solid raw material (S) is not accommodated in the raw material accommodating part 12; and heating means 3 for heating the heating container 10. The heating means 3 has a first heating part 31 having a first heating surface 31a that is arranged facing a main surface part of the raw material accommodating part 12 in a position relation where a whole outer surface of the main surface part is covered, the main surface part being an outer surface side of the heating container 10 and facing the seed crystal attaching part 16. When a cross sectional area of the internal space S is A and an area of the first heating surface 31a is B, a relationship of B / A≥2 is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a SiC single crystal growth apparatus. [Background technology]

[0002] Silicon carbide (SiC) has excellent electrical properties, such as a dielectric breakdown field strength that is about one order of magnitude larger than that of silicon (Si) and a band gap that is about three times larger. In addition, SiC has excellent thermal properties, such as a thermal conductivity that is about three times higher than that of Si. Because of these excellent properties, SiC is expected to be applied to various devices such as power devices, high-frequency devices, and high-temperature operating devices.

[0003] These devices are manufactured by forming an epitaxial layer, which will be the active region of the device, on a SiC single crystal substrate obtained by processing a SiC single crystal ingot, using a method such as chemical vapor deposition (CVD). Among these, the sublimation method is known as a method for manufacturing a SiC single crystal ingot.

[0004] The sublimation method involves placing a seed crystal made of single crystal SiC in a graphite crucible, heating the crucible and supplying the sublimation gas sublimated from the raw material powder (raw material) in the crucible to the seed crystal, thereby growing the seed crystal into a larger single crystal SiC ingot.

[0005] As a crucible used for producing SiC single crystals by such a sublimation method, Patent Document 1 describes a crucible having a plurality of seed crystal placement sections. More specifically, the crucible has a seed crystal placement section in which a seed crystal is placed and a raw material storage section capable of storing a raw material, in which the sublimated raw material gas can reach the seed crystal through the opening of the raw material storage section, and the inner area of ​​the raw material storage section is 3 times or less the area of ​​the opening of the raw material storage section. Furthermore, Patent Document 1 describes, as a crystal growth method, a process of preparing a crystal growth apparatus equipped with such a crucible, and a method of placing a seed crystal in the seed crystal placement section and storing the raw material in the raw material storage section so that the distance between the seed crystal and the raw material is 0.21 times or less the distance between the (centers) of the plurality of seed crystal placement sections.

[0006] As a method for producing a SiC single crystal ingot by sublimation, Patent Document 2 describes a method for improving the uniformity of the temperature of the raw material. More specifically, Patent Document 2 discloses that a raw material part is formed by arranging a high thermal conductivity raw material layer containing a raw material having a high thermal conductivity at the bottom of the crucible, and a low thermal conductivity raw material layer containing a raw material having a low thermal conductivity at least on either the upper side or the lower side of the high thermal conductivity raw material layer, and heating is performed so that the maximum temperature of the raw material part is in the high thermal conductivity raw material layer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2000-219594 A [Patent Document 2] JP 2020-083704 A Summary of the Invention [Problem to be solved by the invention]

[0008] In this regard, in the crucible and crystal growth method of Patent Document 1, the inner area of ​​the raw material container is set to three times or less the area of ​​the opening of the raw material container, thereby stabilizing the vapor pressure, but the examples only describe an example of simultaneously forming seven small SiC single crystals with a diameter of 2 inches, and do not focus on growing large SiC single crystals with a diameter of, for example, 6 inches or more, or growing more SiC single crystals. In particular, when growing large SiC single crystals or growing more SiC single crystals, the volume of the internal space of the crucible (particularly the cross-sectional area of ​​the internal space) becomes too large, and the gaseous raw material derived from the solid raw material generated by sublimating the solid raw material in the crucible cannot be uniformly distributed to the multiple seed crystals arranged in the upper part of the crucible. Therefore, with the crucible and crystal growth method of Patent Document 1, the SiC single crystal grows non-uniformly, resulting in a large amount of wasted raw material, and the crucible becomes large and heavy, making it difficult to handle.

[0009] In addition, in the method of Patent Document 2, the thermal conductivity of the raw material part is controlled by controlling the particle size of the raw material particles constituting each of the high thermal conductivity raw material layer and the low thermal conductivity raw material layer, and the porosity of the high thermal conductivity raw material layer and the low thermal conductivity raw material layer, and when the raw material part is heated, the highest temperature of the raw material part is set in the high thermal conductivity raw material layer of the raw material part, thereby attempting to uniformly sublimate the raw material part. However, the composition of the raw material part changes due to the sublimation of the raw material part, and the thermal conductivity of the raw material part also changes accordingly, so it is difficult to uniformly sublimate the solid raw material throughout the crystal growth.

[0010] An object of the present invention is to provide a SiC single crystal growth apparatus that can uniformly heat solid raw materials contained in a heating container (e.g., multiple crucibles) to sublimate gaseous raw materials derived from the solid raw materials, and that can reduce waste of raw materials when growing SiC single crystals. [Means for solving the problem]

[0011] The inventors discovered that when the cross-sectional area of ​​the internal space of the raw material storage section is A and the area of ​​the first heating surface of the first heating section, which is positioned opposite the main surface of the raw material storage section in a positional relationship covering the entire outer surface of the main surface of the raw material storage section, is B, by satisfying the relationship B / A≧2, the raw material can be uniformly sublimated throughout crystal growth, and thus completed the present invention.

[0012] That is, the gist of the present invention is as follows. (1) A SiC single crystal growth apparatus comprising: a heating vessel having a cylindrical side peripheral portion, the heating vessel having a source material storage section in which a solid source material made of SiC is stored in a portion of an internal space defined by the side peripheral portion, and a seed crystal mounting section in which a SiC seed crystal is placed, on a side of the source material storage section on which the solid source material is not stored; and heating means for heating the heating vessel, the heating means including at least a first heating section having a first heating surface that is located on the outer surface side of the heating vessel and opposed to a main surface portion of the source material storage section that faces the seed crystal mounting section, in a positional relationship that covers the entire outer surface of the main surface portion, and wherein when a cross-sectional area of ​​the internal space is A and an area of ​​the first heating surface is B, the relationship B / A≧2 is satisfied. (2) The SiC single crystal growth apparatus described in (1) above, wherein the heating means further includes a second heating section having a second heating surface that is disposed on the outer surface side of the heating vessel and facing the side peripheral portion of the raw material storage section in a positional relationship that covers the entire outer surface of the side peripheral portion, and wherein when the heating energy by the first heating section is C and the heating energy by the second heating section is D, C is greater than D. (3) The SiC single crystal growth apparatus according to (2) above, wherein the heating energy C by the first heating part and the heating energy D by the second heating part satisfy the relationship C / D≧1.20. (4) The SiC single crystal growth apparatus according to (1), (2), or (3) above, wherein the heating vessel is composed of a plurality of crucibles, the SiC single crystal growth apparatus further includes a chamber that houses the plurality of crucibles and the heating means, and the plurality of crucibles each have a gap portion through which a portion of the gaseous raw material derived from the solid raw material produced by sublimating the solid raw material contained in the raw material storage portion is released from the raw material storage portion into the chamber. (5) A SiC single crystal growth apparatus according to any one of (1) to (4) above, wherein the first heating surface of the heating means is made of an anisotropic material having at least anisotropy in thermal conductivity. (6) The SiC single crystal growth apparatus according to (5) above, wherein the anisotropic material is a carbon material containing carbon fiber. (7) A SiC single crystal growth apparatus according to any one of (1) to (6) above, wherein the heating means includes a heat source for the first heating surface on the rear side of the first heating surface, and the heat source is constituted by a resistance heating means having a three-phase AC power supply mechanism. Effect of the Invention

[0013] According to the present invention, it is possible to provide a SiC single crystal growth apparatus that can uniformly heat a solid raw material contained in a heating container to sublimate gaseous raw material derived from the solid raw material, and that can reduce waste of raw material when growing a SiC single crystal. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing the structure of a main part of a SiC single crystal growth apparatus according to a first embodiment of the present invention, in which FIG. 1(a) is an oblique view showing a see-through state of the internal space S of a crucible, and FIG. 1(b) is a cross-sectional view taken along a virtual plane P1 in FIG. 1(a). [Diagram 2] FIG. 2 is a schematic diagram showing the flow of heat when the heating vessel constituting the SiC single crystal growth apparatus of the first embodiment is heated by a heating means, where FIG. 2(a) shows a case where the relationship B / A≧2 is satisfied, and FIG. 2(b) shows a case where the relationship B / A≧2 is not satisfied. [Diagram 3]FIG. 3 shows the simulation results for the temperature distribution in a SiC single crystal growth apparatus when the B / A ratio is changed, where FIG. 3(a) shows the simulation results when B / A=2, FIG. 3(b) shows the simulation results when B / A=1, and FIG. 3(c) shows the simulation results when B / A=3. [Figure 4] FIG. 4 is a cross-sectional view showing a schematic diagram of a main structure of an SiC single crystal growth apparatus having a first heating section with a heat equalizing plate. [Diagram 5] FIG. 5 is a schematic diagram showing the main structure of a SiC single crystal growth apparatus of a second embodiment according to the present invention, in which FIG. 5(a) is an oblique view showing the internal space S of the crucible in a transparent state, and FIG. 5(b) is a cross-sectional view taken along imaginary plane P2 in FIG. 5(a). [Figure 6] 6A and 6B are schematic diagrams showing the structure of a SiC single crystal growth apparatus of a third embodiment according to the present invention, where FIG. 6A is a perspective view and FIG. 6B is a cross-sectional view taken along imaginary plane P3 in FIG. 6A. [Figure 7] Figure 7 is a schematic diagram showing the heat flow when the heating vessel constituting the SiC single crystal growth apparatus of the second and third embodiments is heated by a heating means, where Figure 7(a) shows the case of the SiC single crystal growth apparatus of the second embodiment, and Figure 7(b) shows the case of the SiC single crystal growth apparatus of the third embodiment. [Figure 8] FIG. 8 is a schematic diagram showing the simulation results of the temperature distribution of a SiC seed crystal placed in a heating vessel of a SiC single crystal growth apparatus when the C / D ratio is changed, where FIG. 8(a) shows the simulation results when the relationship C / D≧2 is satisfied, and FIG. 8(b) shows the simulation results when the relationship C / D≧2 is not satisfied (when C / D=1). [Figure 9] FIG. 9 is a schematic diagram showing the simulation results of the temperature distribution on the surface of the solid source material contained in the heating vessel of a SiC single crystal growth apparatus and the SiC seed crystal placed in the heating vessel when the C / D ratio is changed, where FIG. 9(a) shows the simulation result when C / D=2.00, and FIG. 9(b) shows the simulation result when C / D=1.25. [Figure 10] FIG. 10 is a schematic diagram showing the simulation results of the temperature distribution on the surface of the solid source material contained in the heating vessel of a SiC single crystal growth apparatus and the SiC seed crystal placed in the heating vessel when the B / A ratio and the C / D ratio are changed, where FIG. 10(a) shows the simulation results when B / A=13.3 and C / D=0.50, and FIG. 10(b) shows the simulation results when B / A=0.30 and C / D=1.25. [Figure 11] Figure 11 shows schematic diagrams of simulation results for the temperature distribution on the surface of a solid raw material contained in a heating vessel of a SiC single crystal growth apparatus when the magnification of thermal conductivity in a direction along the first heating surface relative to the thermal conductivity in a direction perpendicular to the first heating surface is changed, with Figure 11(a) showing the simulation result when the magnification is 10x, Figure 11(b) showing the simulation result when the magnification is 4x, Figure 11(c) showing the simulation result when the magnification is 3x, and Figure 11(d) showing the simulation result when the magnification is 2x. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, SiC single crystal growth apparatuses according to some embodiments of the present invention will be described below.

[0016] First Embodiment FIG. 1 is a diagram showing a schematic structure of a main part of a SiC single crystal growth apparatus according to a first embodiment of the present invention, in which FIG. 1(a) is a perspective view showing the internal space S of the crucible in a see-through state, and FIG. 1(b) is a cross-sectional view of a virtual plane P1 in FIG. 1(a). FIG. 2 is a diagram showing a schematic heat flow when a heating vessel constituting the SiC single crystal growth apparatus of the first embodiment is heated by a heating means, in which FIG. 2(a) shows a case where the relationship B / A≧2 is satisfied, and FIG. 2(b) shows a case where the relationship B / A≧2 is not satisfied. FIG. 3 shows a simulation result of the temperature distribution of the SiC single crystal growth apparatus when the B / A ratio is changed, in which FIG. 3(a) shows a simulation result when B / A=2, FIG. 3(b) shows a simulation result when B / A=3, and FIG. 3(c) shows a simulation result when B / A=1.

[0017] As shown in FIG. 1 , a SiC single crystal growth apparatus 1 according to a first embodiment of the present invention includes a heating vessel 10 having a cylindrical side peripheral portion 14, a source material accommodation section 12 in which a solid source material M(s) made of SiC is accommodated in a portion of an internal space S partitioned off by the side peripheral portion 14, and a seed crystal mounting section 16 in which a SiC seed crystal 2 is placed, on the side of the internal space S of the source material accommodation section 12 where the solid source material M(s) is not accommodated; and a heating means 3 for heating the heating vessel 10. The heating means 3 includes at least a first heating section 31 having a first heating surface 31a that is arranged opposite a main surface portion of the source material accommodation section 12 that is on the outer surface side of the heating vessel 10 and faces the seed crystal mounting section 16, in a positional relationship covering the entire outer surface of the main surface portion. When the cross-sectional area of ​​the internal space S is A and the area of ​​the first heating surface 31a is B, the relationship B / A≧2 is satisfied.

[0018] In this way, the first heating section 31 is disposed as the heating means 3 in a positional relationship covering the entire outer surface of the main surface portion such as the bottom surface portion 15 of the raw material storage section 12, and the area B of the first heating surface 31a of the first heating section 31 is set to be at least twice the cross-sectional area A of the internal space S, so that the entire main surface portion of the raw material storage section 12 is heated by the first heating section 31, and the first heating surface 31a of the first heating section 31 extends not only to the portion facing the raw material storage section 12 but also to the outside of the raw material storage section 12, which is considered to make it difficult for heat H to leak from the vicinity of the outer periphery of the first heating section 31 to the outside of the first heating section 31. Therefore, the SiC single crystal growth apparatus 1 can uniformly heat the solid raw material M(s) contained inside the raw material storage section 12 of the heating vessel 10 (e.g., multiple crucibles 11) to sublimate the gas raw material derived from the solid raw material. Furthermore, by uniformly heating and sublimating the solid source material M(s), the uniformity of the growth rate of the SiC single crystal for each seed crystal and the uniformity of the growth rate within each seed crystal when growing the SiC single crystal can be improved, thereby reducing waste of source material when cutting out substrates or the like from the obtained SiC single crystal.

[0019] The SiC single crystal growth apparatus 1 according to this embodiment includes at least a heating vessel 10 and a heating means 3.

[0020] (About the heating container) Among these, the heating vessel 10 is constituted by one or more crucibles 11. Particularly, in this embodiment, the heating vessel 10 is constituted by one crucible 11.

[0021] The crucibles 11 constituting the heating vessel 10 each have a cylindrical peripheral side portion 14, and have a source material accommodation section 12 in which a solid source material M(s) made of SiC is accommodated in a part of an internal space S partitioned and formed by the peripheral side portion 14. Here, the source material accommodation section 12 is composed of, for example, a bottom portion 13 and a cylindrical peripheral side portion 14 connected to the bottom portion 13.

[0022] The solid raw material M(s) contained in the raw material containing section 12 is preferably contained in a portion of the internal space S of the crucible 11 defined by the side peripheral section 14 in the height direction Y. The solid raw material M(s) is preferably contained in a main surface portion of the crucible 11 that is disposed opposite a first heating surface 31a of the first heating section 31 described later. When the crucible 11 is disposed above the first heating section 31, as shown in FIG. 1, for example, the main surface portion of the crucible 11 is a bottom surface portion 15 at the bottom 13 of the crucible 11. On the other hand, when the crucible 11 is disposed below the first heating section 31, the main surface portion is an upper surface portion at the lid of the crucible 11, and the solid raw material M(s) is contained on the surface facing the upper surface portion (not shown).

[0023] Moreover, the crucible 11 constituting the heating vessel 10 has a seed crystal attachment part 16 in which a SiC seed crystal 2 is placed, on the side of the internal space S in the raw material storage part 12 where the solid raw material M(s) is not stored. As a result, the solid raw material M(s) and the seed crystal 2 are placed in the internal space S, which is the same space, and therefore when the heating vessel 10 is heated by the heating means 3 described below, the gas raw material M(g) generated by sublimation of the solid raw material M(s) stored in the raw material storage part 12 can reach the seed crystal 2, and as a result, a SiC single crystal can be grown.

[0024] Here, there is no particular limitation on the size of the SiC seed crystal 2 attached by the seed crystal attachment portion 16. The SiC single crystal growth apparatus 1 of the present embodiment can uniformly sublimate the solid source material M(s) facing the seed crystal 2 even when a crystal with a large growth surface area is used as the seed crystal 2, for example, a crystal with a diameter of more than 2 inches (50.8 mm) or a crystal with a diameter of 6 inches (152.4 mm) or more, to grow a larger SiC single crystal, and therefore can efficiently grow the SiC single crystal.

[0025] The means for attaching the seed crystal 2 to the crucible 11 with the seed crystal mounting part 16 is not particularly limited. For example, from the viewpoint of facing the lower surface of the seed crystal 2 to the solid raw material M(s), the seed crystal mounting part 16 may be configured to have a pedestal protruding from the inner wall of the crucible 11 and to hold the outer periphery of the seed crystal 2.

[0026] Furthermore, the crucible 11 constituting the heating vessel 10 is preferably provided with a lid 17 in order to increase the vapor pressure inside the crucible 11 of the gaseous raw material M(g) generated by sublimation of the solid raw material M(s).

[0027] The material of the crucible 11 is desirably made of a material that can withstand high temperatures, since the material becomes hot when the solid raw material M(s) is sublimated to grow a SiC single crystal. Examples of materials that can withstand such high temperatures include graphite, graphite coated with tantalum, and tantalum carbide.

[0028] (About heating method) The heating means 3 is disposed on the outer surface side of the heating container 10 and heats the heating container 10. By providing the heating means 3 for heating the heating container 10, the solid source material M(s) contained in the heating container 10 can be heated, thereby causing the solid source material M(s) to sublimate. The gas source material M(g) generated by sublimation passes through the internal space S partitioned and formed by the side peripheral portion 14 of the crucible 11, reaches the seed crystal 2, and is cooled by the seed crystal 2, thereby allowing the growth of a SiC single crystal.

[0029] The SiC single crystal growth apparatus 1 of this embodiment has at least a first heating part 31 as the heating means 3. The first heating part 31 has a first heating surface 31a disposed opposite to a main surface part of the source material housing part 12 facing the seed crystal mounting part 16 of the heating vessel 10 in a positional relationship covering the entire outer surface of this main surface part. This allows the first heating part 31 to heat the entire main surface part of the source material housing part 12 on which the first heating part 31 is disposed.

[0030] 1, when the crucible 11 is disposed above the first heating section 31, the bottom surface 15 of the crucible 11 can be the main surface of the raw material storage section 12. On the other hand, when the crucible 11 is disposed below the first heating section 31, the top surface of the crucible 11 can be the main surface of the raw material storage section 12 (not shown).

[0031] The first heating section 31 constituting the heating means 3 and the crucible 11 constituting the heating vessel 10 are configured to satisfy the relationship B / A≧2, where A is the cross-sectional area of ​​the internal space S of the crucible 11 and B is the area of ​​the first heating surface 31a.

[0032] In this way, as the heating means 3, the first heating section 31 is positioned relative to a main surface portion such as the bottom portion 15 of the raw material storage section 12 in a positional relationship such that it covers the entire outer surface of the main surface portion, and the area B of the first heating surface 31a of the first heating section 31 is made at least twice the cross-sectional area A of the internal space S of the crucible 11.This allows the entire main surface portion of the raw material storage section 12 to be heated by the first heating section 31, and the first heating surface 31a of the first heating section 31 extends not only to the portion facing the raw material storage section 12 but also to the outside of the raw material storage section 12.

[0033] More specifically, as shown in Fig. 2(a), the first heating surface 31a of the first heating section 31 extends from the main surface portion of the raw material accommodating section 12 (the bottom surface portion 15 in Fig. 2(a)) toward at least one side along the surface direction of this main surface portion when viewed in a cross section perpendicular to the first heating surface 31a. More preferably, the first heating surface 31a extends from the main surface portion of the raw material accommodating section 12 toward both sides along the surface direction of this main surface portion.

[0034] Here, by providing the first heating section 31, the heating means 3, in which the first heating surface 31a extends from the main surface portion of the raw material storage section 12, as shown in Fig. 2(a), the heat H emitted from the first heating surface 31a of the first heating section 31 is evenly transferred to the main surface portion of the raw material storage section 12 (bottom surface portion 15 in Fig. 2(a)) by the first heating surface 31a extending from the main surface portion of the raw material storage section 12, so that the solid raw material M(s) stored inside the raw material storage section 12 can be heated evenly. The reason why the main surface portion of the raw material storage section 12 can be heated evenly in this way is that the heat H is unlikely to leak from the vicinity of the outer periphery of the first heating section 31 to the outside of the first heating section 31. On the other hand, when the relationship B / A≧2 is not satisfied, particularly in the comparative SiC single crystal growth apparatus 90 in which the first heating surface 31a does not extend from the main surface portion of the raw material storage section 12 as shown in FIG. 2(b), it is considered that heat H leaks from near the outer periphery of the first heating section 31 to the outside of the first heating section 31, making it difficult to heat the main surface portion of the raw material storage section 12 evenly.

[0035] In this way, the ratio of the area B of the first heating surface 31a of the first heating part 31 to the cross-sectional area A of the internal space S is configured to be 2 or more from the viewpoint of uniformly sublimating the solid raw material M(s). On the other hand, the upper limit of the ratio of the area B of the first heating surface 31a of the first heating part 31 to the cross-sectional area A of the internal space S is not particularly limited, but may be 3 or less from the viewpoint of reducing thermal waste, for example.

[0036] FIG. 3 shows the results when the ratio (B / A ratio) of the area B of the first heating surface 31a of the first heating unit 31 to the cross-sectional area A of the internal space S is changed and the heating power is 40 W / cm 2The temperature distribution of the SiC single crystal growth apparatus when heated at an energy density of 10 ... On the other hand, when the ratio of the area B of the first heating surface 31a of the first heating section 31 to the cross-sectional area A of the internal space S is smaller than 2, for example, when the ratio of B to A is 1, the temperature of the solid raw material M(s) contained in the raw material storage section 12 of the crucible 11 is lower than 2002°C in part as shown in Fig. 3(b), and it is considered that the uniformity of heating the solid raw material M(s) is reduced. Even when the ratio of the area B of the first heating surface 31a of the first heating section 31 to the cross-sectional area A of the internal space S is large, it is considered that the solid raw material M(s) contained in the raw material storage section 12 of the crucible 11 is heated uniformly as shown in Fig. 3(c), but the solid raw material M(s) is heated to 2340°C or more, which may result in thermal waste.

[0037] The type of the heat source 33 of the first heating section 31 constituting the heating means 3 is not particularly limited, and known means such as resistance heating and induction heating can be used. Among them, from the viewpoint of easy control of the amount of heat generated from the heat source 33, it is preferable to configure it by a resistance heating means, and more preferably to configure it by a resistance heating means having a three-phase AC power supply mechanism. In addition, from the viewpoint of improving the heat balance in the first heating section 31, it is preferable to provide the heat source 33 of the first heating section 31 on the back side of the first heating surface 31a. Furthermore, the first heating surface 31a of the first heating section 31 may be the surface of the heat source 33 constituting the first heating section 31 as in the SiC single crystal growth apparatus 1 shown in FIG. 1, or may be the surface of a heat equalizing plate 34 which is a plate-shaped member provided between the heat source 33 and the bottom surface of the heating vessel 10 and approximately parallel to the bottom surface of the heating vessel 10 as in the SiC single crystal growth apparatus 1A shown in FIG. 4, and which constitutes a part of the first heating section 31 together with the heat source 33.

[0038] In the heating means 3, 3A, the first heating surface 31a of the first heating section 31, 31A is preferably made of an anisotropic material having at least anisotropy in thermal conductivity. Here, the heat source 33 and the heat equalizer plate 34 having the first heating surface 31a preferably have a higher thermal conductivity in the direction along the first heating surface 31a than in the direction perpendicular to the first heating surface 31a. This makes the heat conduction along the thickness direction of the heat source 33 and the heat equalizer plate 34 gentle, and promotes the heat conduction along the first heating surface 31a. Therefore, the heat can be evenly transferred to the entire first heating surface 31a, and the heat can be evenly generated from the first heating surface 31a toward the crucible 11. As a result, the solid raw material M(s) can be heated more uniformly.

[0039] In particular, when resistance heating or induction heating is used as the heat source, it is possible that heat generation along the first heating surface 31a may become non-uniform due to the shape of the heat source itself, the presence of electrodes that supply electricity to the heat source, the presence of a support that supports the heat source, etc. Even in such a case, by forming the first heating surface 31a from an anisotropic material having anisotropy in thermal conductivity as described above, it is possible to generate heat uniformly from the first heating surface 31a toward the crucible 11.

[0040] As such an anisotropic material, it is preferable to use a carbon material containing carbon fiber. An example of a carbon material containing carbon fiber is a C / C composite material (Carbon Fiber Reinforced Carbon Composite). This allows the thermal conductivity of the first heating surface 31a to be anisotropic due to the orientation of the carbon fibers, and also allows the mechanical strength of the anisotropic material, such as tensile strength and bending strength, to be improved. Furthermore, the improved mechanical strength allows the heat source 33 and the heat equalizer plate 34, which are made of anisotropic materials, to be made thinner, and this allows the heat capacity of the heat source 33 and the heat equalizer plate 34 to be reduced and these to be heated quickly while appropriately supporting the crucible 11, etc., and therefore also allows the energy required for growing SiC single crystals to be reduced.

[0041] In the anisotropic material, the ratio of the thermal conductivity in the direction along the first heating surface 31a to the thermal conductivity in the direction perpendicular to the first heating surface 31a is preferably 2 or more, and more preferably 4 or more. On the other hand, the upper limit of the ratio of the thermal conductivity in the direction along the first heating surface 31a to the thermal conductivity in the direction perpendicular to the first heating surface 31a is not particularly limited, but from the viewpoint of facilitating the transfer of heat from the heat source to the crucible 11, the upper limit may be 10 times.

[0042] Such an anisotropic material can be formed by arranging carbon fiber along the surface that will become the first heating surface 31a when forming a material that can withstand high temperatures, such as graphite. In this case, the carbon fiber may be thin carbon felt or carbon paper arranged along the surface that will become the first heating surface 31a.

[0043] The thickness of the anisotropic material is preferably 3 mm or more from the viewpoint of increasing the mechanical strength of the first heating parts 31, 31A and facilitating their insertion and removal from the SiC single crystal growth apparatus 1, 1A. On the other hand, the thickness of the anisotropic material is preferably 30 mm or less from the viewpoint of not blocking heat from the heat source.

[0044] <Second embodiment> Fig. 5 is a schematic diagram showing the main structure of a SiC single crystal growth apparatus of a second embodiment according to the present invention, in which Fig. 5(a) is a perspective view showing the internal space S of the crucible as seen through, and Fig. 5(b) is a cross-sectional view taken along imaginary plane P2 of Fig. 5(a). In the following description, the same components as those of the first embodiment are given the same reference numerals, and their description will be omitted or simplified, and differences will be mainly described.

[0045] In the above-mentioned first embodiment, as shown in Figs. 1(a) and (b), the heating vessel 10 has a single crucible 11, but the present invention is not limited thereto. For example, as shown in Fig. 5(a) of an SiC single crystal growth apparatus 1B, the heating vessel 10B may be composed of a plurality of crucibles 11a to 11g. This allows a single SiC single crystal growth apparatus 1B to simultaneously grow a plurality of SiC single crystals, and since the crucibles are individualized compared to the case where a large crucible is used, the weight of the crucibles can be reduced and the handling can be made easier. Furthermore, by configuring the heating vessel 10B with a plurality of crucibles 11a to 11g, the uniform sublimation of the solid raw material M(s) can be further promoted.

[0046] Here, the heating means 3 preferably disposes the first heating section 31 in a positional relationship covering the entire outer surface of the main surface of the raw material storage section 12 for all of the crucibles 11a to 11g constituting the heating vessel 10B. The first heating section 31 constituting the heating means 3 and the crucibles 11a to 11g constituting the heating vessel 10B are configured to satisfy the relationship B / A≧2, where A is the cross-sectional area of ​​each of the internal spaces S of the crucibles 11a to 11g and B is the area of ​​the first heating surface 31a. By configuring the heating vessel 10B and the first heating section 31 in this way, even when a plurality of SiC single crystals are grown simultaneously using one SiC single crystal growth apparatus 1B, the solid raw material M(s) can be uniformly sublimated as shown in FIG. 5(b) to promote uniform growth of SiC single crystals from the seed crystals 2a to 2c, thereby improving the productivity of SiC single crystals.

[0047] The SiC single crystal growth apparatus 1B preferably includes a plurality of crucibles 11a-11g constituting the heating vessel 10B, and a chamber 5 for accommodating the heating vessel 10B. This makes it possible to easily adjust the atmosphere outside the heating vessel 10B, and also makes it possible to prevent damage to the crucibles 11a-11g, etc. due to heating.

[0048] At this time, as shown in Fig. 5(b), it is preferable that the multiple crucibles 11a-11c have gaps 18a-18c that release a part of the gaseous source M(g) derived from the solid source, generated by sublimating the solid source M(s) contained in each of the source containers 12a-12c, from the source containers into the chamber 5. This allows impurities to be discharged from the crucibles 11a-11c through the gaps 18a-18c. At the same time, the gaseous source M(g) is released into the chamber 5 through the gaps 18a-18c of the multiple crucibles 11a-11c, filling the chamber 5, and the vapor pressure of the gaseous source M(g) in the chamber 5 is shared among the multiple crucibles 11a-11c, so that the vapor pressure of the gaseous source M(g) in the multiple crucibles 11a-11c becomes approximately uniform (damping effect). This makes it possible to suppress changes over time in the composition of the source gas M(g) due to impurities in the crucibles 11a to 11c, and to further promote uniform growth of a plurality of SiC single crystals.

[0049] Here, the gaps 18a to 18c can be formed by providing gaps at fitting parts when assembling the crucibles 11a to 11c, as shown in Fig. 5(b). Examples of the fitting parts when assembling the crucibles 11a to 11c include fitting parts between the raw material storage parts 12a to 12c and the seed crystal mounting parts 16a to 16c, and fitting parts between the seed crystal mounting parts 16a to 16c and the lid parts 17a to 17c.

[0050] The number of crucibles constituting the heating vessel 10B of the SiC single crystal growth apparatus 1B is not particularly limited. For example, from the viewpoint of not unnecessarily widening the gap between the crucibles, it is preferable that the number is 7 or more. On the other hand, the number of crucibles provided in the SiC single crystal growth apparatus 1B may be 19 or less.

[0051] The spacing between the multiple crucibles 11a to 11g that make up the heating vessel 10B is not particularly limited, but from the viewpoint of improving the balance of vapor pressure between the crucibles 11a to 11g, the spacing may be less than half the size of the crucibles 11a to 11g along the first heating surface 31a.

[0052] <Third embodiment> Fig. 6 is a schematic diagram showing the structure of a SiC single crystal growth apparatus of a third embodiment according to the present invention, Fig. 6(a) is a perspective view, and Fig. 6(b) is a cross-sectional view in the virtual plane P3 of Fig. 6(a). Fig. 7 is a diagram showing the flow of heat when the heating vessel constituting the SiC single crystal growth apparatus of the second and third embodiments is heated by a heating means, Fig. 7(a) shows the case of the SiC single crystal growth apparatus of the second embodiment, and Fig. 7(b) shows the case of the SiC single crystal growth apparatus of the third embodiment. In the following description, the same components as those of the first or second embodiment are given the same reference numerals, and the description thereof is omitted or simplified, and the differences are mainly described.

[0053] In the above-mentioned second embodiment, as shown in Fig. 5(a) and (b), the heating means 3 includes a first heating section 31 that covers the entire outer surface of the main surface of the raw material housing section 12, but is not limited thereto. For example, as in the SiC single crystal growth apparatus 1C shown in Fig. 6(a) and (b), in addition to the first heating section 31, a second heating section 32 having a second heating surface 32a may be disposed to face the side peripheral sections 14a-14c of the raw material housing sections 12a-12c in a positional relationship covering the entire outer surfaces of the side peripheral sections 14a-14c.

[0054] Here, when the heating energy by the first heating section 31 and the second heating section 32 constituting the heating means 3C is C and the heating energy by the second heating section 32 is D, it is preferable that C is greater than D.

[0055] In this manner, by making the heating energy C by the first heating section 31 greater than the heating energy D by the second heating section 32, the solid source material M(s) contained inside the source material storage sections (source material storage sections 12a to 12c in FIG. 6(b)) of the crucibles 11a to 11g is uniformly heated, and by arranging the crystal growth surfaces of the seed crystals 2a to 2c parallel to the first heating surface 31a, the surface temperatures of the seed crystals 2a to 2c placed in the crucibles 11a to 11g are also uniform, thereby further improving the uniformity of the growth rate of the SiC single crystal.

[0056] Here, the heating means 3C in the SiC single crystal growth apparatus 1C is provided with a first heating section 31 as well as a second heating section 32, and the heating energy C by the first heating section 31 is made greater than the heating energy D by the second heating section 32. As a result, as shown in FIG. 7(b), heat H generated from the first heating surface 31a of the first heating section 31 is evenly transferred to the side away from the first heating surface 31a (the upper side in FIG. 7(b)), and the isotherms L1 to L3 become approximately parallel to the first heating surface 31a, making it possible to make the surface temperatures of the seed crystals 2a to 2c uniform. The reason why the surface temperatures of the seed crystals 2a to 2c can be made uniform in this way is that the presence of the second heating part 32 makes it more difficult for the heat H to leak from the vicinity of the outer periphery of the first heating part 31 to the outside of the first heating part 31, and the heat H locally lost due to leakage to the outside of the first heating part 31 is replenished by the second heating part 32, resulting in equal energy densities in the internal spaces S of the crucibles 11a to 11c. On the other hand, as shown in FIG. 7(a), in the SiC single crystal growth apparatus 1B of the second embodiment not including the second heating part 32, the isotherms L1' to L3' approach the first heating surface 31a in a portion close to the outside of the first heating part 31, so that part of the heat H leaks from the vicinity of the outer periphery of the first heating part 31 to the outside of the first heating part 31, making it difficult to make the surface temperatures of the seed crystals 2a to 2c uniform. Furthermore, if the heating energy D by the second heating part is too large, the isotherm will move away from the first heating surface in a portion near the outside of the first heating part, making it difficult to make the surface temperatures of the seed crystals 2a to 2c uniform (not shown).

[0057] Thus, the ratio of the heating energy C by the first heating section to the heating energy D by the second heating section (C / D ratio) is preferably greater than 1.00 and more preferably equal to or greater than 1.20 from the viewpoint of uniforming the surface temperatures of the seed crystals 2a to 2c. On the other hand, the upper limit of the ratio of the heating energy C by the first heating section to the heating energy D by the second heating section (C / D ratio) is not particularly limited, but may be less than 3.50 or equal to or less than 3.00 from the viewpoint of heating the solid raw material M(s) more uniformly, for example.

[0058] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and includes all aspects encompassed by the concept of the present invention and the scope of the claims, and can be modified in various ways within the scope of the present invention. EXAMPLES

[0059] Next, in order to clarify the effects of the present invention, examples of the present invention will be described, but the present invention is not limited to these examples.

[0060] [Example 1] As a model of a crucible 11 containing a solid raw material M(s) and a seed crystal 2, a model was constructed in which the crucible 11 had a cylindrical internal space S of 180 mm in diameter and 60 mm in height, and had a raw material containing section 12 in which the internal space S was formed by a cylindrical side peripheral portion 14 with an inner diameter of 180 mm. The crucible 11 contained SiC powder (manufactured by Pacific Random Co., Ltd., model number: GMF-H) as the solid raw material M(s) at a height of 70 mm from the bottom of the internal space S, and further provided a seed crystal mounting section 16 at a height of 60 mm from the bottom of the internal space S, and placed a seed crystal 2 having a diameter of 150 mm.

[0061] Nineteen of these models of the crucible 11 were placed at equal intervals on a flat first heating unit 31 having a first heating surface 31a with a diameter of 1100 mm, as shown in FIG. 8(a). At this time, the cross-sectional area A of the internal space S in each crucible 11 was 2.54×10 4 mm 2 , the area B of the first heating surface 31a is 9.50×10 6 mm 2 Therefore, the B / A ratio was 37.4.

[0062] Here, the first heating section 31 is configured to include a plate-shaped heat equalizer 34 having the above-mentioned first heating surface 31a, which is provided approximately parallel to the bottom surface of the crucible 11, and a heat source 33 provided on the back side of the first heating surface 31a of the heat equalizer 34 and constituted by a resistance heating means having a three-phase AC power supply mechanism. Among these, the heat equalizer 34 is made of a C / C composite material which is an anisotropic material, and the thermal conductivity of this anisotropic material in a direction perpendicular to the first heating surface 31a is set to 10 W / mK, and the thermal conductivity in a direction along the first heating surface 31a is set to 40 W / mK. Therefore, the thermal conductivity in the direction along the first heating surface 31a is four times the thermal conductivity in the direction perpendicular to the first heating surface 31a.

[0063] An apparatus model for simulating the surface temperature of the solid source material M(s) of a SiC single crystal growth apparatus was constructed in such a manner that a cylindrical second heating section 32 with an inner diameter of 1200 mm and a height of 230 mm was arranged outside the first heating section 31 so as to be concentric with the first heating section 31 in a plan view. The surface temperature of the solid source material M(s) when heated for 300 minutes with heating energy C by the first heating section of 80 kW and heating energy D by the second heating section of 40 W was simulated using FEMTET (product name) manufactured by Murata Software Co., Ltd. At this time, the ratio of heating energy C by the first heating section to heating energy D by the second heating section (C / D ratio) was 2.00.

[0064] As a result of the simulation, it was found that the temperature difference in the surface temperature of the solid source material M(s) was 10° C. or less. In addition, as shown in FIG. 8(a) showing the simulation result of the temperature distribution of the SiC seed crystal placed in the crucible 11 of the SiC single crystal growth apparatus 1D, it was found that the temperature difference in the surface temperature of the SiC seed crystal 2 was also 10° C. or less.

[0065] [Example 2] The surface temperature of the solid raw material M(s) was simulated when the solid raw material M(s) was heated for 300 minutes with the heating energy C by the first heating part being 60 kW and the heating energy D by the second heating part being 60 kW, using the same equipment model as in Invention Example 1. At this time, the ratio of the heating energy C by the first heating part to the heating energy D by the second heating part (C / D ratio) was 1.00.

[0066] As a result of the simulation, it was found that the temperature difference in the surface temperature of the solid source material M(s) was 10° C. or less. On the other hand, as shown in FIG. 8(b) showing the simulation result of the temperature distribution of the SiC seed crystal placed in the crucible 11 of the SiC single crystal growth apparatus 1E, including the surface of the solid source material M(s), the temperature difference in the surface temperature of the SiC seed crystal 2 was in the range of more than 30° C. and not more than 40° C.

[0067] [Example 3] Using the same model of crucible 11 as in Example 1 of the present invention, seven pieces were placed at equal intervals on a flat first heating part 31 having a first heating surface 31a with a diameter of 650 mm, as shown in FIG. 9(a). At this time, the cross-sectional area A of the internal space S in each crucible 11 was 2.54×10 4 mm 2 , the area B of the first heating surface 31a is 3.31×10 5 mm 2 Therefore, the B / A ratio was 13.0.

[0068] Here, the first heating section 31 was configured to have a heat equalizing plate 34 and a heat source 33 arranged therein, similarly to the first example of the present invention. The heat equalizing plate 34 was made of a C / C composite material, which is an anisotropic material, and the thermal conductivity of this anisotropic material in a direction perpendicular to the first heating surface 31a was set to 10 W / mK, and the thermal conductivity in a direction along the first heating surface 31a was set to 40 W / mK. Therefore, the thermal conductivity in the direction along the first heating surface 31a was four times that in the direction perpendicular to the first heating surface 31a.

[0069] In addition, an apparatus model for simulating the surface temperature of the solid source material M(s) of the SiC single crystal growth apparatus was constructed in such a manner that a cylindrical second heating section 32 with an inner diameter of 750 mm and a height of 230 mm was arranged outside the first heating section 31 so as to be concentric with the first heating section 31 in a plan view. The surface temperature of the solid source material M(s) when heated for 300 minutes with heating energy C by the first heating section of 40 kW and heating energy D by the second heating section of 20 kW was simulated using FEMTET (product name) manufactured by Murata Software Co., Ltd. At this time, the ratio of heating energy C by the first heating section to heating energy D by the second heating section (C / D ratio) was 2.00.

[0070] 9(a) shows a simulation result (left side) of the temperature distribution on the surface of the solid source material M(s) contained in the crucible 11 of the SiC single crystal growth apparatus 1F, and a simulation result (right side) of the temperature distribution of the SiC seed crystal 2 placed in the crucible 11. As a result of the simulation, it was found that the temperature difference between the surface temperature of the solid source material M(s) and the surface temperature of the seed crystal 2 were both 10° C. or less.

[0071] [Example 4] The surface temperature of the solid raw material M(s) was simulated when the solid raw material M(s) was heated for 300 minutes using the same equipment model as in Example 3 of the present invention, with the heating energy C by the first heating part being 25 kW and the heating energy D by the second heating part being 20 kW. At this time, the ratio of the heating energy C by the first heating part to the heating energy D by the second heating part (C / D ratio) was 1.25.

[0072] 9(b) shows the simulation results (left side) of the temperature distribution on the surface of the solid source material M(s) contained in the crucible 11 of the SiC single crystal growth apparatus 1G, and the simulation results (right side) of the temperature distribution of the SiC seed crystal 2 placed in the crucible 11. As a result of the simulation, it was found that the temperature difference between the surface temperature of the solid source material M(s) and the surface temperature of the seed crystal 2 were both 10° C. or less.

[0073] [Example 5] The surface temperature of the solid raw material M(s) was simulated when the solid raw material M(s) was heated for 300 minutes using the same equipment model as in Example 3 of the present invention, with the heating energy C by the first heating part being 20 kW and the heating energy D by the second heating part being 40 kW. At this time, the ratio of the heating energy C by the first heating part to the heating energy D by the second heating part (C / D ratio) was 0.50.

[0074] 10(a) shows the results of a simulation (left side) of the temperature distribution on the surface of the solid source material M(s) contained in the crucible 11 of the SiC single crystal growth apparatus 1H, and the results of a simulation (right side) of the temperature distribution of the SiC seed crystal 2 placed in the crucible 11. As a result of the simulation, it was found that the temperature difference on the surface of the solid source material M(s) was 10°C or less. On the other hand, the temperature difference on the surface of the SiC seed crystal 2 was in the range of more than 20°C to 30°C or less.

[0075] [Comparative Example 1] Using the same model of crucible 11 as in Example 1 of the present invention, seven pieces were placed at equal intervals on a flat first heating part 31 having a first heating surface 31a with a diameter of 98.6 mm, as shown in FIG. 10(b). At this time, the cross-sectional area A of the internal space S in each crucible 11 was 2.54×10 4 mm 2 , the area B of the first heating surface 31a is 7.63×10 3 mm 2 Therefore, the B / A ratio was 0.30.

[0076] In addition, an apparatus model for simulating the surface temperature of the solid source material M(s) of the SiC single crystal growth apparatus was constructed in such a manner that a cylindrical second heating section 32 with an inner diameter of 750 mm and a height of 230 mm was arranged outside the first heating section 31 so as to be concentric with the first heating section 31 in a plan view. The surface temperature of the solid source material M(s) when heated for 300 minutes with the heating energy C by the first heating section being 25 kW and the heating energy D by the second heating section being 20 kW was simulated using FEMTET (product name) manufactured by Murata Software Co., Ltd. At this time, the ratio of the heating energy C by the first heating section to the heating energy D by the second heating section (C / D ratio) was 1.25.

[0077] 10(b) shows the results of a simulation (left side) of the temperature distribution on the surface of the solid source material M(s) contained in the crucible 11 of the SiC single crystal growth apparatus 1I, and the results of a simulation (right side) of the temperature distribution on the SiC seed crystal 2 placed in the crucible 11. As a result of the simulation, a temperature difference occurred in the surface temperature of the solid source material M(s) in the range of more than 20°C to 30°C. The temperature difference on the surface temperature of the seed crystal 2 was 10°C or less.

[0078] [Example 6] Using the same model of crucible 11 as in Example 1 of the present invention, seven pieces were placed at equal intervals on a flat first heating part 31 having a first heating surface 31a with a diameter of 650 mm, as shown in FIG. 11(a). At this time, the cross-sectional area A of the internal space S in each crucible 11 was 2.54×10 4 mm 2 , the area B of the first heating surface 31a is 3.31×10 5 mm 2 Therefore, the B / A ratio was 13.0.

[0079] Here, the first heating section 31 was configured to have a heat equalizing plate 34 and a heat source 33 arranged therein, similarly to the invention example 1. The heat equalizing plate 34 was made of a C / C composite material, which is an anisotropic material, and the thermal conductivity of this anisotropic material in a direction perpendicular to the first heating surface 31a was set to 1 W / mK, and the thermal conductivity in a direction along the first heating surface 31a was set to 10 W / mK. Therefore, the thermal conductivity in the direction along the first heating surface 31a was 10 times the thermal conductivity in the direction perpendicular to the first heating surface 31a.

[0080] In addition, an apparatus model for simulating the surface temperature of the solid source material M(s) of the SiC single crystal growth apparatus was constructed in such a manner that a cylindrical second heating section 32 with an inner diameter of 750 mm and a height of 230 mm was arranged outside the first heating section 31 so as to be concentric with the first heating section 31 in a plan view. The surface temperature of the solid source material M(s) when heated for 300 minutes with the heating energy C by the first heating section being 25 kW and the heating energy D by the second heating section being 20 kW was simulated using FEMTET (product name) manufactured by Murata Software Co., Ltd. At this time, the ratio of the heating energy C by the first heating section to the heating energy D by the second heating section (C / D ratio) was 1.25.

[0081] 11(a) shows the results of a simulation of the temperature distribution on the surface of the solid source material M(s) contained in the crucible 11 of the SiC single crystal growth apparatus 1J. As a result of the simulation, the temperature difference on the surface of the solid source material M(s) was 10° C. or less.

[0082] [Example 7] For the same device model as in Example 6 of the present invention, the surface temperature of the solid raw material M(s) was simulated when the thermal conductivity of the C / C composite material, which is the anisotropic material constituting the heat equalizing plate 34, in the direction perpendicular to the first heating surface 31a was set to 10 W / mK and the thermal conductivity in the direction along the first heating surface 31a was set to 40 W / mK. At this time, the thermal conductivity in the direction along the first heating surface 31a was four times that in the direction perpendicular to the first heating surface 31a.

[0083] 11(b) shows the results of a simulation of the temperature distribution on the surface of the solid source material M(s) contained in the crucible 11 of the SiC single crystal growth apparatus 1K. As a result of the simulation, the temperature difference on the surface of the solid source material M(s) was 10°C or less.

[0084] [Example 8] For the same device model as in Example 6 of the present invention, the surface temperature of the solid raw material M(s) was simulated when the thermal conductivity of the C / C composite material, which is the anisotropic material constituting the heat equalizing plate 34, in the direction perpendicular to the first heating surface 31a was set to 13.3 W / mK and the thermal conductivity in the direction along the first heating surface 31a was set to 40 W / mK. At this time, the thermal conductivity in the direction along the first heating surface 31a was three times that in the direction perpendicular to the first heating surface 31a.

[0085] 11(c) shows the results of a simulation of the temperature distribution on the surface of the solid source material M(s) contained in the crucible 11 of the SiC single crystal growth apparatus 1L. As a result of the simulation, the temperature difference on the surface of the solid source material M(s) was 20°C or less.

[0086] [Example 9] For the same device model as in Example 6 of the present invention, the surface temperature of the solid raw material M(s) was simulated when the thermal conductivity of the C / C composite material, which is the anisotropic material constituting the heat equalizing plate 34, in the direction perpendicular to the first heating surface 31a was set to 20 W / mK and the thermal conductivity in the direction along the first heating surface 31a was set to 40 W / mK. At this time, the thermal conductivity in the direction along the first heating surface 31a was multiplied by two to the thermal conductivity in the direction perpendicular to the first heating surface 31a.

[0087] 11(d) shows the results of a simulation of the temperature distribution on the surface of the solid source material M(s) contained in the crucible 11 of the SiC single crystal growth apparatus 1M. As a result of the simulation, the temperature difference on the surface of the solid source material M(s) was 20°C or less.

[0088] From the above, it was found that in the SiC single crystal growth apparatuses of Examples 1 to 9 of the present invention, the ratio (B / A) of the area B of the first heating surface to the cross-sectional area A of the internal space was 2 or more, and the temperature difference on the surface temperature of the solid source material M(s) was small, resulting in almost uniform heating.

[0089] Therefore, the SiC single crystal growth apparatus of Examples 1 to 9 of the present invention was capable of uniformly heating the solid raw material and sublimating the gaseous raw material derived from the solid raw material, thereby reducing waste of raw material when growing SiC single crystal.

[0090] On the other hand, in the SiC single crystal growth apparatus of Comparative Example 1, the ratio (B / A) of the area B of the first heating surface to the cross-sectional area A of the internal space was less than 2. Therefore, in the SiC single crystal growth apparatus of Comparative Example 1, variation was observed in the surface temperature of the solid source material M(s).

[0091] Furthermore, as shown in Figures 8 to 10, in the SiC single crystal growth apparatuses of Examples 1, 3, and 4 of the present invention, the ratio of the heating energy C by the first heating section to the heating energy D by the second heating section (C / D ratio) exceeds 1.00, and therefore the surface temperature of the seed crystal 2 is also found to be almost uniform, unlike Examples 2 and 5 of the present invention, in which the C / D ratio is below 1.00.

[0092] Furthermore, in the SiC single crystal growth apparatus of Examples 1 to 7 of the present invention, as shown in Figures 8 to 11, first heating surface 31a is formed from an anisotropic material in which the thermal conductivity in the direction along first heating surface 31a is four or more times greater than the thermal conductivity in the direction perpendicular to first heating surface 31a, and it was found that this makes it possible to reduce the temperature difference in the surface temperature of the solid source material M(s) more than in Examples 8 and 9 of the present invention, in which first heating surface 31a is formed from a material in which the thermal conductivity is less than four times greater. [Explanation of symbols]

[0093] 1. 1A~1M SiC single crystal growth equipment 10, 10B, 10C heating container 11, 11a~11g crucible 12, 12a to 12c Raw material storage section 13 Bottom of raw material storage section 14, 14a to 14c: Side peripheral portion of raw material storage section 15 Bottom part of raw material storage section 16, 16a-16c Seed crystal mounting part 17, 17a~17c lid part 18a~18c Gap 2. 2a-2c SiC seed crystals 3 Heating means 31 1st heating section 31a 1st heating surface 32 2nd heating section 32a 2nd heating surface 33 Heat source 34 Soaking plate 4. Insulation 5. Chamber 90 Comparative SiC single crystal growth equipment A: Area of ​​the internal space B Area of ​​the first heating surface H Heat flow from the heating means L1~L3, L1'~L3' isotherm S interior space Y Height direction M(s) solid raw material M(g) Gas source

Claims

1. A raw material storage section having a cylindrical side peripheral portion, the raw material storage section storing a solid raw material made of SiC in a portion of an internal space defined by the side peripheral portion; a heating vessel having a seed crystal mounting portion on which a seed crystal of SiC is placed, on a side of the internal space of the source material storage portion where the solid source material is not stored; A heating means for heating the heating container, the heating means includes at least a first heating section having a first heating surface disposed opposite a main surface portion of the raw material accommodation section that is on the outer surface side of the heating vessel and faces the seed crystal mounting section in a positional relationship covering the entire outer surface of the main surface portion, When the cross-sectional area of ​​the internal space is A and the area of ​​the first heating surface is B, a relationship of B / A≧2 is satisfied, the heating means further includes a second heating section having a second heating surface that is disposed on the outer surface side of the heating container and faces the side peripheral portion of the raw material storage section in a positional relationship that covers the entire outer surface of the side peripheral portion, A SiC single crystal growth apparatus, wherein C is greater than D, where C is the heating energy by the first heating part and D is the heating energy by the second heating part.

2. 2. The SiC single crystal growth apparatus according to claim 1, wherein the heating energy C by the first heating part and the heating energy D by the second heating part satisfy a relationship of C / D≧1.

20.

3. A raw material storage section having a cylindrical side peripheral portion, the raw material storage section storing a solid raw material made of SiC in a portion of an internal space defined by the side peripheral portion; a heating vessel having a seed crystal mounting portion on which a seed crystal of SiC is placed, on a side of the internal space of the source material storage portion where the solid source material is not stored; A heating means for heating the heating container, the heating means includes at least a first heating section having a first heating surface disposed opposite a main surface portion of the raw material accommodation section that is on the outer surface side of the heating vessel and faces the seed crystal mounting section in a positional relationship covering the entire outer surface of the main surface portion, When the cross-sectional area of ​​the internal space is A and the area of ​​the first heating surface is B, a relationship of B / A≧2 is satisfied, A SiC single crystal growth apparatus, wherein the first heating surface of the heating means is made of an anisotropic material having at least anisotropy in thermal conductivity.

4. The SiC single crystal growth apparatus according to claim 3 , wherein the anisotropic material is a carbon material containing carbon fibers.

5. The heating vessel is composed of a plurality of crucibles, The SiC single crystal growth apparatus further comprises a chamber that accommodates the plurality of crucibles and the heating means; 5. The SiC single crystal growth apparatus according to claim 1, wherein the plurality of crucibles each have a gap portion through which a portion of a gaseous raw material derived from a solid raw material generated by sublimating the solid raw material contained in each of the raw material containing portions is released from the raw material containing portion into the chamber.

6. The heating means includes a heat source for the first heating surface on the rear side of the first heating surface, 6. The SiC single crystal growth apparatus according to claim 1, wherein the heat source is constituted by a resistance heating means having a three-phase AC power supply mechanism.

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