JP4877204B2 - Silicon carbide single crystal manufacturing equipment - Google Patents

Description

  The present invention relates to an apparatus for producing a silicon carbide (hereinafter referred to as SiC) single crystal that can be used for a material such as a semiconductor or a light emitting diode.

  Conventionally, a sublimation recrystallization method has been widely used as a method for growing a SiC single crystal. This sublimation recrystallization method involves joining a seed crystal to a graphite pedestal placed in a graphite crucible, heating and sublimating the SiC raw material arranged at the bottom of the crucible, and supplying the sublimation gas to the seed crystal. To grow a SiC single crystal.

  In a SiC single crystal manufacturing apparatus using such a sublimation recrystallization method, for example, a graphite crucible is used as a container constituting the growth space of the SiC single crystal. A conventional graphite crucible includes a bottomed cylindrical crucible body having an open top surface and a lid member that closes the opening of the crucible body. Then, with the portion protruding at the center of the lid as a pedestal, an SiC single crystal substrate serving as a seed crystal is bonded onto the pedestal via an adhesive or the like, and SiC raw material powder is disposed on the bottom surface of the crucible body. .

  Using the graphite crucible having such a configuration, the raw material powder is heated and sublimated by a heating device arranged on the outer periphery of the graphite crucible and supplied to the surface of the SiC single crystal substrate. A single crystal is grown.

  However, if the SiC single crystal substrate to be a seed crystal is directly attached to a graphite pedestal with an adhesive or the like, thermal stress is applied to the SiC single crystal substrate and the grown SiC single crystal due to the difference in thermal expansion coefficient between SiC and graphite. Occurs, and crystal defects are generated in the SiC single crystal.

In order to solve this problem, techniques disclosed in Patent Documents 1 to 3 have been proposed. Specifically, in Patent Document 1, a protective film is disposed on the back surface of an SiC single crystal substrate that serves as a seed crystal, and the outer periphery of the SiC single crystal substrate is bonded without adhering the SiC single crystal substrate and the protective film to a pedestal. Fixing with the surrounding hook suppresses generation of thermal stress in the SiC single crystal substrate. In Patent Document 2, a buffer material is disposed between an SiC single crystal substrate that serves as a seed crystal and a pedestal, and the SiC single crystal substrate is bonded to the pedestal with an adhesive via the buffer material, whereby an SiC single crystal substrate is obtained. The generation of thermal stress is suppressed. In Patent Document 3, a protective film is disposed on the back surface of an SiC single crystal substrate that serves as a seed crystal, a buffer material is disposed between the SiC single crystal substrate and the protective film, and a pedestal, and the SiC single crystal is interposed via the buffer material. By sticking the crystal substrate and the protective film to the pedestal with an adhesive, the occurrence of thermal stress on the SiC single crystal substrate is suppressed.
JP 2002-201097 A JP 2004-269297 A JP 2004-338971 A

  However, in the structure of Patent Document 1, due to a gap generated between the SiC single crystal substrate and the graphite pedestal, and in the structures of Patent Documents 2 and 3, the SiC single crystal grown on the pedestal of the buffer having poor heat conduction. Heat dissipation will be hindered. For this reason, the growth rate of the SiC single crystal is reduced, and the in-plane temperature distribution of the grown crystal becomes non-uniform, which causes crystal defects in the SiC single crystal.

  In addition, although the SiC single crystal manufacturing apparatus in the case of using the sublimation recrystallization method has been described here, the same problem also applies to the SiC single crystal manufacturing apparatus using the gas supply method in which the source gas is supplied from the outside of the graphite crucible. There is.

  In view of the above points, the present invention suppresses the generation of thermal stress due to the difference in thermal expansion coefficient between the SiC single crystal substrate serving as the seed crystal and the pedestal, and releases heat from the SiC single crystal serving as the grown crystal to the pedestal. It aims at providing the manufacturing apparatus of the SiC single crystal which can perform this well.

  In order to achieve the above object, in the present invention, a container (1) used in a SiC single crystal production apparatus in a sublimation recrystallization method or a gas supply method is composed of a hollow main body (1a) having an open surface and a main body (1a). ) And a base (5) on which the SiC single crystal substrate (3) is arranged, and the lid (1b) and the base (5) are provided. The pedestal (5) is composed of three or more layers of graphite members (5a to 5c), and the thermal expansion coefficient β of each of the multiple layers of graphite members (5a to 5c). It is characterized in that the average value is closer to the thermal expansion coefficient β of the silicon carbide substrate (3) than the thermal expansion coefficient β of each of the multiple-layer graphite members (5a to 5c).

  Thus, the pedestal (5) has a multilayer structure of three or more layers, and the average value of the thermal expansion coefficient β of the multiple-layer graphite members (5a to 5c) is the thermal expansion coefficient of the SiC single crystal substrate (3). It is close to β. Therefore, even if the SiC single crystal substrate (3) is attached to the pedestal (5), the SiC single crystal substrate (3) and the grown SiC single crystal are different due to the difference in thermal expansion coefficient β between SiC and graphite. Generation of thermal stress in (4) can be suppressed, and generation of crystal defects in the SiC single crystal (4) can be suppressed. Thereby, since it becomes possible to affix a SiC single crystal substrate (3) to a base (5), the heat dissipation to the base (5) of a SiC single crystal substrate (3) and a SiC single crystal (4) is prevented. Without a decrease in the growth rate of the SiC single crystal (4). And it can prevent that the in-plane temperature distribution of a growth crystal becomes non-uniform | heterogenous, and can suppress generating a crystal defect in a SiC single crystal (4).

  Specifically, the temperature at which the average value of the thermal expansion coefficient β of each of the multiple layers of graphite members (5a to 5c) exceeds 1000 ° C. exceeds 1000 ° C. of each of the multiple layers of graphite members (5a to 5c). It is preferable that the thermal expansion coefficient β of the silicon carbide substrate (3) be closer to the thermal expansion coefficient β at a temperature exceeding 1000 ° C. than the thermal expansion coefficient β.

  For example, the average value of the thermal expansion coefficient β at 2500 ° C. of each of the multiple layers of graphite members (5a to 5c) constituting the pedestal (5) is calculated as the heat at 2500 ° C. of each of the multiple layers of graphite members (5a to 5c). The thermal expansion coefficient β at 2500 ° C. of the silicon carbide substrate (3) may be closer to the expansion coefficient β.

  Further, the average value of the thermal expansion coefficient β of 1000 ° C. or less of each of the multiple layers of graphite members (5a to 5c) is set to be smaller than the thermal expansion coefficient β of 1000 ° C. or less of each of the multiple layers of graphite members (5a to 5c). The average value of the thermal expansion coefficient β at a temperature close to the thermal expansion coefficient β of 1000 ° C. or less of the silicon carbide substrate (3) and exceeding 1000 ° C. of each of the multiple-layer graphite members (5a to 5c). It is preferable to make the thermal expansion coefficient β of the silicon carbide substrate (3) closer to the thermal expansion coefficient β of the silicon carbide substrate (3) than the thermal expansion coefficient β of the graphite member (5a to 5c) at a temperature higher than 1000 ° C.

  As described above, the average value of the thermal expansion coefficient β of the multiple-layer graphite members (5a to 5c) can be brought close to the SiC single crystal substrate (3) not only at a temperature exceeding 1000 ° C. but also at 1000 ° C. or less. As a result, it becomes possible to obtain the effects of the above characteristics more remarkably.

  For example, the temperature exceeding 1000 ° C. can be exemplified at 2500 ° C., and the temperature below 1000 ° C. can be exemplified as 1000 ° C.

  In the above description, the average value of the thermal expansion coefficient β of each of the multiple-layer graphite members (5a to 5c) is described as being close to the thermal expansion coefficient β of the SiC substrate (3). The best.

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

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

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing a state in which a SiC single crystal is grown using the SiC single crystal manufacturing apparatus according to the present embodiment.

  As shown in FIG. 1, a cylindrical graphite crucible 1 is used as a container of a SiC single crystal production apparatus. The graphite crucible 1 is obtained by sublimating the SiC raw material powder (SiC raw material) 2 provided at the bottom of the graphite crucible 1 by heating and supplying the sublimated raw material gas, thereby forming a relatively low temperature seed crystal. The SiC single crystal 4 is grown on a SiC single crystal substrate 3 having a certain thickness, for example, 1 mm.

  The graphite crucible 1 includes a bottomed cylindrical crucible body 1a having an open top surface and a lid 1b that closes the opening of the crucible body 1a. A pedestal 5 is bonded to the central portion of the lid 1b constituting the graphite crucible 1.

  The pedestal 5 is configured as follows so that the thermal expansion coefficient is substantially equal to that of SiC. Specifically, the pedestal 5 is configured by, for example, a multilayer structure of three or more layers having the same thickness. In the present embodiment, the pedestal 5 is configured by a three-layer structure of first, second, and third graphite members 5a, 5b, and 5c. Has been. Each of the first to third graphite members 5a to 5c is a circular plate material having a diameter substantially the same as that of the SiC single crystal substrate 3 which is a seed crystal, and carbon powder, a polymer material (for example, phenol resin), an organic solvent ( For example, phenol and ethyl alcohol) are used as adhesives 5d and 5f. These adhesives 5d and 5e have a thickness of 0.001 to 0.1 mm.

  The first to third graphite members 5a to 5c are composed of carbon powder and a polymer material (for example, phenol) in which the first graphite member 5a located closest to the lid 1b among the first to third graphite members 5a to 5c. Resin) and an organic solvent (for example, phenol and ethyl alcohol) as a raw material, the base 5 is configured by being attached to the lid member 1b via an adhesive 6 and is located closest to the SiC single crystal substrate 3 side. The SiC single crystal substrate 3 is bonded to the graphite member 5c via an adhesive 7 made of carbon powder, a polymer material (for example, phenol resin), and an organic solvent (for example, phenol and ethyl alcohol).

The first and third graphite members 5a and 5c and the second graphite member 5b sandwiched between the first and third graphite members 5a and 5c are made of graphite having different thermal expansion coefficients. The selection of the thermal expansion coefficient β of the first to third graphite members 5a to 5c is performed based on the thermal expansion coefficient β of the SiC single crystal substrate 3 serving as a seed crystal, and the first to third graphites at 2500 ° C. The average value of the thermal expansion coefficients of members 5 a to 5 c is made substantially equal to the thermal expansion coefficient β of SiC single crystal substrate 3. For example, the first and third graphite members 5a and 5c are made of graphite having a thermal expansion coefficient β of 8 × 10 ⁻⁶ [1 / K] at 2500 ° C., and the second graphite member 5b is heated at 2500 ° C. It is made of graphite having an expansion coefficient β of 2 × 10 ⁻⁶ [1 / K]. When graphite having such a thermal expansion coefficient is selected, the average value of the thermal expansion coefficients of the first to third graphite members 5a to 5c is 6 × 10 ⁻⁶ [1 / K], and the heat of the SiC single crystal substrate 3 is increased. It becomes a value equivalent to 6 × 10 ⁻⁶ [1 / K] which is the expansion coefficient β. Note that the coefficient of thermal expansion β of graphite can be adjusted as appropriate depending on the compression force when taking the mold, etc., and manufacturers have various thermal expansion coefficients β as specs. It is possible to appropriately select the thermal expansion coefficient β of the three graphite members 5a to 5c.

  By configuring the pedestal 5 with such a thermal expansion coefficient β of the first to third graphite members 5a to 5c, the thermal expansion coefficient between the pedestal 5 and the SiC single crystal substrate 3 which becomes a seed crystal during crystal growth. The generation of stress due to the difference is suppressed.

  A graphite crucible 1 is provided outside the graphite crucible 1 by an unillustrated heating device such as an induction coil so as to surround the outer periphery of the graphite crucible 1. The graphite crucible 1 is controlled by controlling the power of the heating device. It is configured so that the temperature inside can be controlled. For example, when the SiC single crystal 4 is grown, the temperature of the SiC single crystal substrate 3 as a seed crystal is kept at a temperature about 100 ° C. lower than the temperature of the SiC raw material powder 2 by adjusting the power of the heating device. Can be drunk. Moreover, although not shown in figure, the graphite crucible 1 is accommodated in the vacuum vessel which can introduce | transduce argon gas, and it can heat now in this vacuum vessel.

  An SiC single crystal manufacturing process using the SiC single crystal manufacturing apparatus configured as described above will be described.

  First, the SiC raw material powder 2 is disposed on the bottom surface side of the main body 1a of the graphite crucible 1, and the SiC single crystal, which is a seed crystal, is bonded to the pedestal 5 bonded to the lid 1b via the adhesive 6. A crystal substrate 3 is attached. Then, the lid 1b is attached to the main body 1a, the graphite crucible 1 is accommodated in a vacuum container (not shown), and the inside of the vacuum container is made an argon gas atmosphere. Then, the temperature of SiC raw material powder 2 is heated to 2000-2500 degreeC with the heating apparatus which is not illustrated, and the temperature of SiC single crystal substrate 3 becomes lower than the temperature of SiC raw material powder 2 by adjustment of a heating apparatus, etc. In addition, a temperature gradient is provided in the graphite crucible 1.

  Next, the pressure in the graphite crucible 1 is adjusted to 13.3 Pa to 26.7 kPa by adjusting the degree of vacuum of the vacuum vessel, and when the sublimation growth starts, the SiC raw material powder 2 sublimates to become a sublimation gas, and SiC The SiC single crystal 4 grows on the surface of the SiC single crystal substrate 3 that reaches the single crystal 4 and is at a relatively lower temperature than the SiC raw material powder 2 side. Thereafter, the SiC single crystal 4 is grown while making the amount of reduction of the SiC raw material powder 2 constant. For example, the temperature distribution in the graphite crucible 1 can be adjusted by adjusting the power of the heating device. By doing in this way, the silicon / carbon ratio in the crucible 1 can be stabilized.

  During the growth of the SiC single crystal 4, thermal stress due to a difference in thermal expansion coefficient is generated between the first to third graphite members 5 a to 5 c constituting the pedestal 5, the SiC single crystal substrate 3, and the SiC single crystal 4. there is a possibility. However, as described above, since the average value of the thermal expansion coefficient β of the first to third graphite members 5a to 5c is substantially equal to the thermal expansion coefficient β of the SiC single crystal substrate 3, the pedestal 5 and the SiC single crystal Warping of substrate 3 and SiC single crystal 4 can be suppressed.

In order to confirm this effect, the thermal expansion coefficient β at 2500 ° C. of the first and third graphite members 5a and 5c is 8 × 10 ⁻⁶ [1 / K], and the thermal expansion coefficient of the second graphite member 5b at 2500 ° C. Thermal stress analysis was performed by simulation with β being 2 × 10 ⁻⁶ [1 / K] and the thermal expansion coefficient β of the SiC single crystal substrate 3 and the SiC single crystal 4 being 6 × 10 ⁻⁶ [1 / K]. .

  FIG. 2A is a schematic cross-sectional view of the pedestal 5, the SiC single crystal substrate 3, and the SiC single crystal 4 used for the thermal stress analysis, and FIG. 2B shows the thermal stress displacement distribution of the pedestal 5. FIG. As shown in this figure, it can be seen that the pedestal 5 is not warped and is distributed almost straight and evenly in the thickness direction. From this result, it can be said that the warp of the pedestal 5 can be suppressed, and the influence of the warp of the pedestal 5 can be suppressed from being transmitted to the SiC single crystal substrate 3 and the SiC single crystal 4.

Moreover, generation | occurrence | production of the crystal defect of the obtained SiC single crystal 4 can be suppressed because curvature can be suppressed in this way. Actually, the dislocation density in the SiC single crystal 4 was confirmed and found to be 3000 / cm ² which is equivalent to the SiC single crystal substrate 3 which is the seed crystal.

  Furthermore, since SiC single crystal substrate 3 can be affixed to pedestal 5, the heat dissipation of SiC single crystal substrate 3 and SiC single crystal 4 to pedestal 5 is not hindered. For this reason, a decrease in the growth rate of the SiC single crystal 4 can be prevented. When this growth rate was measured, it was 0.5 mm / h, which is larger than the growth rate of 0.3 mm / h when a buffer material is used as in the prior art.

  As described above, in the present embodiment, the pedestal 5 is constituted by a multilayer structure of three or more layers, and the average value of the thermal expansion coefficients β of the first to third graphite members 5a to 5c is determined by the SiC single crystal substrate 3. The coefficient of thermal expansion is approximately equal to β. For this reason, even if the SiC single crystal substrate 3 is attached to the pedestal 5, thermal stress is generated in the SiC single crystal substrate 3 and the grown SiC single crystal 4 due to the difference in thermal expansion coefficient between SiC and graphite. This can be suppressed, and the occurrence of crystal defects in the SiC single crystal 4 can be suppressed. As a result, the SiC single crystal substrate 3 can be attached to the pedestal 5, so that the heat dissipation of the SiC single crystal substrate 3 and the SiC single crystal 4 to the pedestal 5 is not hindered, and the SiC single crystal 4 is grown. A decrease in speed can be prevented. And it can prevent that the in-plane temperature distribution of a growth crystal becomes non-uniform | heterogenous, and can suppress generating a crystal defect in the SiC single crystal 4. FIG.

As a reference, an experiment was conducted to determine whether the same effect can be obtained when the pedestal 5 has two layers. Specifically, assuming a configuration in which the first graphite member 5a and the second graphite member 5b are bonded together with an adhesive 5d as the pedestal 5, the first graphite member 5a side is attached to the lid 1b with the adhesive 6. The SiC single crystal substrate 3 is pasted on the second graphite member 5b side with an adhesive 7 and the thermal expansion coefficient β at 2500 ° C. of the first graphite member 5a is 8 × 10 ⁻⁶ [1 / K], the thermal expansion coefficient β of the second graphite member 5b at 2500 ° C. is 4 × 10 ⁻⁶ [1 / K], and the thermal expansion coefficients β of the SiC single crystal substrate 3 and the SiC single crystal 4 are 6 × 10 ⁻⁶ [ 1 / K], thermal stress analysis was performed by simulation.

FIG. 3A is a schematic cross-sectional view of the pedestal 5, the SiC single crystal substrate 3 and the SiC single crystal 4 used for the thermal stress analysis, and FIG. 3B shows the thermal stress displacement distribution of the pedestal 5. FIG. As shown in this figure, it can be seen that the base 5 is warped and has a distribution inclined in the thickness direction. Also from this result, it can be said that the influence on the SiC single crystal substrate 3 and the SiC single crystal 4 cannot be prevented by warping the base 5. Therefore, it is effective to make the base 5 have a multilayer structure of three or more layers. Further, when the dislocation density in the SiC single crystal 4 was confirmed, it was 10000 / cm ² which was larger than that of the SiC single crystal substrate 3 which is a seed crystal. However, since it is a structure in which the SiC single crystal substrate 3 is directly attached to the pedestal 5, it is possible to prevent a decrease in the growth rate of the SiC single crystal 4 and, as described above, as in the case where the pedestal 5 has a three-layer structure, The growth rate was 0.5 mm / h.

(Second Embodiment)
A second embodiment of the present invention will be described. The SiC single crystal manufacturing apparatus of the present embodiment is obtained by changing the selection of the thermal expansion coefficient β of the first to third graphite members 5a to 5c with respect to the first embodiment. Therefore, only different parts will be described.

In the first embodiment, for example, the thermal expansion coefficient β at 2500 ° C. of the first and third graphite members 5a and 5c is 8 × 10 ⁻⁶ [1 / K], and the thermal expansion coefficient of the second graphite member 5b at 2500 ° C. The case where β is 2 × 10 ⁻⁶ [1 / K] has been described. This is because the thermal expansion coefficient β at 2500 ° C. of the SiC single crystal substrate 3 and the SiC single crystal 4 is assumed to be 6 × 10 ⁻⁶ [1 / K], but the thermal expansion coefficient β at 1000 ° C. is For example, it may be 5 × 10 ⁻⁶ [1 / K]. In this case, as in the first embodiment, the average value of the thermal expansion coefficients β of the first to third graphite members 5a to 5c at 2500 ° C. may be 6 × 10 ⁻⁶ [1 / K]. The average value of the thermal expansion coefficient β of the first to third graphite members 5a to 5c at 1000 ° C. is 5 × 10 ⁻⁶ [1 / K] which is equivalent to the thermal expansion coefficient β of the SiC single crystal substrate 3 or the SiC single crystal 4. Does not necessarily match.

For this reason, in this embodiment, the graphite which comprises the 1st-3rd graphite members 5a-5c is selected also considering the thermal expansion coefficient (beta) in 1000 degreeC. Specifically, the first and third graphite members 5a and 5c have a thermal expansion coefficient β at 1000 ° C. of 7.5 × 10 ⁻⁶ [1 / K] and a thermal expansion coefficient β at 2500 ° C. of 8 ×. The second graphite member 5b is composed of 10 ⁻⁶ [1 / K] graphite, and the thermal expansion coefficient β at 1000 ° C. is 1 × 10 ⁻⁶ [1 / K], and the thermal expansion coefficient β at 2500 ° C. Is made of 2 × 10 ⁻⁶ [1 / K] graphite. By using such graphite, the average value of the thermal expansion coefficient of the first to third graphite members 5a to 5c is 5 × 10 ⁻⁶ [1 / K] when the temperature is 1000 ° C., and ⁶ when the average temperature is 2500 ° C. Since × 10 ⁻⁶ [1 / K], the thermal expansion coefficient β of the SiC single crystal substrate 3 and the SiC single crystal 4 is equal to both at 1000 ° C. and 2500 ° C.

  Thus, not only at 2500 ° C. but also at 1000 ° C., the average value of the thermal expansion coefficient β of the first to third graphite members 5 a to 5 c is the thermal expansion coefficient of the SiC single crystal substrate 3 or the SiC single crystal 4. By making it equal to β, the effects shown in the first embodiment can be obtained more remarkably.

(Third embodiment)
A third embodiment of the present invention will be described. In the first and second embodiments, the SiC single crystal manufacturing apparatus using the sublimation recrystallization method has been described. In the present embodiment, an SiC single crystal manufacturing apparatus using the gas supply method will be described. The basic structure of the SiC single crystal manufacturing apparatus described in the present embodiment is substantially the same as that of the first embodiment, and only different parts will be described.

  FIG. 4 is a cross-sectional view showing a state in which the SiC single crystal is grown using the SiC single crystal manufacturing apparatus according to the present embodiment. As shown in this figure, a gas supply passage 1c is provided on the bottom surface of a crucible body 1a of a graphite crucible 1, and a raw material gas is introduced through the gas supply passage 1c. A gap is formed between the lid 1b and the crucible body, and the source gas is continuously discharged onto the growth surface of the SiC single crystal substrate 3 or the grown SiC single crystal 4 by discharging the source gas through the gap. It is set as the structure supplied.

  Also in the SiC single crystal manufacturing apparatus using such a gas supply method, the first base or the second embodiment has the same structure as that of the first embodiment or the second embodiment. It is possible to obtain the same effect as in the second embodiment.

(Other embodiments)
In the above embodiment, the case where the pedestal 5 has a three-layer structure has been described, but a multilayer structure of three or more layers may be used. In this case, if the average value of 2500 ° C. of the thermal expansion coefficient β of each layer constituting the pedestal 5 is substantially equal to the thermal expansion coefficient β at 2500 ° C. of the SiC single crystal substrate 3 or the SiC single crystal 4, the first is achieved. The same effect as the embodiment can be obtained. Furthermore, if the average value of the thermal expansion coefficient β of each layer constituting the pedestal 5 at 1000 ° C. is made substantially equal to the thermal expansion coefficient β at 1000 ° C. of the SiC single crystal substrate 3 or the SiC single crystal 4, the second embodiment is carried out. The same effect as the form can be obtained.

  In each of the above embodiments, an example of the thermal expansion coefficient β of each layer constituting the pedestal 5 has been described. However, these are merely examples, and other thermal expansion coefficients β may be selected. I do not care. In this case, it is best that the average value of the thermal expansion coefficient β of 1000 ° C. or 2500 ° C. of each layer is equal to the thermal expansion coefficient β of 1000 ° C. or 2500 ° C. of the SiC single crystal substrate 3 or SiC single crystal 4. It is not necessarily required to be completely equivalent, and at least the average value of the thermal expansion coefficient β when averaged with the thermal expansion coefficient β of the other layers is higher than the individual thermal expansion coefficient β of each layer. If the thermal expansion coefficient β of the substrate 3 or the SiC single crystal 4 is approached, the above effect can be obtained although the effect is reduced as compared with the above embodiments.

  Moreover, in the said 2nd Embodiment, the average value of the thermal expansion coefficient (beta) of the 1st-3rd graphite members 5a-5c in 1000 degreeC or 2500 degreeC is each of these 1st-3rd graphite members 5a-5c. An example was given in which the thermal expansion coefficient β at 1000 ° C. or 2500 ° C. of the silicon carbide substrate 3 was made closer to the thermal expansion coefficient β at 1000 ° C. or 2500 ° C. However, these are merely examples, and at least the average value of the thermal expansion coefficient β of 1000 ° C. or less of each of the first to third graphite members 5a to 5c is that of each of the first to third graphite members 5a to 5c. The temperature that is closer to the thermal expansion coefficient β of 1000 ° C. or lower of the silicon carbide substrate 3 than the thermal expansion coefficient β of 1000 ° C. or lower, and exceeds the respective 1000 ° C. of the first to third graphite members 5a to 5c. The thermal expansion coefficient β of the silicon carbide substrate 3 at a temperature exceeding 1000 ° C. is higher than the thermal expansion coefficient β at a temperature exceeding 1000 ° C. of each of the first to third graphite members 5a to 5c. If they are close to each other, the above effects can be obtained.

It is sectional drawing which showed a mode that the SiC single crystal was grown using the SiC single crystal manufacturing apparatus concerning 1st Embodiment of this invention. (A) is the cross-sectional schematic diagram of the base 5, the SiC single crystal substrate 3, and the SiC single crystal 4 which were used for the thermal stress analysis, (b) is the figure which showed the displacement distribution of the thermal stress in the base 5. . (A) is the cross-sectional schematic diagram of the base 5, the SiC single crystal substrate 3, and the SiC single crystal 4 which were used for the thermal stress analysis, (b) is the figure which showed the displacement distribution of the thermal stress in the base 5. . It is sectional drawing which showed a mode that the SiC single crystal was grown using the manufacturing apparatus of the SiC single crystal concerning 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Graphite crucible, 1a ... Main body, 1b ... Cover material, 1c ... Raw material gas supply path, 2 ... SiC raw material powder, 3 ... Single crystal substrate, 4 ... SiC single crystal, 5 ... Base, 5a-5c ... 1st -3rd graphite member, 5d, 5e ... adhesive, 6, 7 ... adhesive

Claims (11)

A silicon carbide single crystal substrate (3) serving as a seed crystal is placed in a container (1), and a silicon carbide source gas is supplied to the surface of the silicon carbide single crystal substrate (3) to thereby form the silicon carbide single crystal. In a silicon carbide single crystal manufacturing apparatus for growing a silicon carbide single crystal (4) on a substrate (3),
The container (1)
A hollow body (1a) having an open surface;
A lid (1b) disposed on the one surface side of the main body (1a) to be opened;
A pedestal (5) on which the silicon carbide single crystal substrate (3) is disposed,
The lid member (1b) and the pedestal (5) are composed of separate members, and the pedestal (5) is composed of multiple layers of graphite members (5a to 5c) composed of three or more layers, The thermal expansion of the silicon carbide substrate (3) is such that the average value of the thermal expansion coefficient β of each of the multiple layers of graphite members (5a to 5c) is greater than the thermal expansion coefficient β of each of the multiple layers of graphite members (5a to 5c). An apparatus for producing a silicon carbide single crystal characterized by being close to a coefficient β. The average thermal expansion coefficient β of each of the multiple-layer graphite members (5a to 5c) at a temperature exceeding 1000 ° C. is a thermal expansion coefficient at a temperature exceeding 1000 ° C. for each of the multiple-layer graphite members (5a to 5c). The apparatus for producing a silicon carbide single crystal according to claim 1, wherein the silicon carbide substrate (3) is closer to a thermal expansion coefficient β of a temperature exceeding 1000 ° C than β. The average value of the thermal expansion coefficient β at 2500 ° C. of each of the plurality of layers of graphite members (5a to 5c) constituting the pedestal (5) is the heat at 2500 ° C. of each of the plurality of layers of graphite members (5a to 5c). The apparatus for producing a silicon carbide single crystal according to claim 2, wherein the thermal expansion coefficient β of the silicon carbide substrate (3) at 2500 ° C is made closer to the expansion coefficient β. The average value of the thermal expansion coefficient β of 1000 ° C. or less of each of the multiple-layer graphite members (5a to 5c) is more than the thermal expansion coefficient β of 1000 ° C. or less of each of the multiple-layer graphite members (5a to 5c). Average value of thermal expansion coefficient β at a temperature exceeding 1000 ° C. of each of the multiple-layer graphite members (5a to 5c), which is close to the thermal expansion coefficient β of 1000 ° C. or less of the silicon carbide substrate (3). Is closer to the thermal expansion coefficient β of the silicon carbide substrate (3) than 1000 ° C. than the thermal expansion coefficient β of the temperature exceeding 1000 ° C. of each of the multiple-layer graphite members (5a to 5c). The apparatus for producing a silicon carbide single crystal according to claim 1. The average value of the thermal expansion coefficient β at 1000 ° C. of each of the multiple layers of graphite members (5a to 5c) is greater than the thermal expansion coefficient β of 1000 ° C. of each of the multiple layers of graphite members (5a to 5c). The thermal expansion coefficient β of 1000 ° C. of the substrate (3) is approximated, and the average value of the thermal expansion coefficient β of 2500 ° C. of each of the multilayer graphite members (5a to 5c) is the multilayer graphite. 5. The silicon carbide according to claim 4, wherein a thermal expansion coefficient β of 2500 ° C. of the silicon carbide substrate (3) is closer to a thermal expansion coefficient β of 2500 ° C. of each of the members (5 a to 5 c). Single crystal manufacturing equipment. 2. The carbonization according to claim 1, wherein an average value of the thermal expansion coefficients β of the plurality of layers of graphite members (5 a to 5 c) is equal to the thermal expansion coefficient β of the silicon carbide substrate (3). Silicon single crystal manufacturing equipment.
The average value of the thermal expansion coefficient β at 2500 ° C. of each of the multiple-layer graphite members (5a to 5c) constituting the pedestal (5) is equivalent to the thermal expansion coefficient β at 2500 ° C. of the silicon carbide substrate (3). The apparatus for producing a silicon carbide single crystal according to claim 2, wherein: The average value of the thermal expansion coefficient β at 1000 ° C. of each of the multiple layers of graphite members (5a to 5c) is equivalent to the thermal expansion coefficient β of 1000 ° C. of the silicon carbide substrate (3), and the multiple layers The average value of the thermal expansion coefficient β at 2500 ° C. of each of the graphite members (5a to 5c) is equal to the thermal expansion coefficient β at 2500 ° C. of the silicon carbide substrate (3). The manufacturing apparatus of the silicon carbide single crystal of description. The multilayered graphite member (5a to 5c) is bonded with an adhesive (5d, 5e) using carbon powder, a polymer material, and an organic solvent as raw materials. The manufacturing apparatus of the silicon carbide single crystal as described in any one. The apparatus for producing a silicon carbide single crystal according to claim 9, wherein the polymer material is a phenol resin, and the organic solvent is phenol and ethyl alcohol. The thickness of the said adhesive agent (5d, 5e) is 0.001-0.1 mm, The manufacturing apparatus of the silicon carbide single crystal of Claim 9 or 10 characterized by the above-mentioned.

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