JP2019043788A - Method and apparatus for growing single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a solid-liquid interface shape during single crystal growth. SOLUTION: The single crystal growing method is solidified in a melting step S4 for melting a seed crystal 3 and a single crystal raw material 4 arranged inside a pit 1 and a melt in the pit 1 generated in the melting step S4. The arrangement step S5 in which the liquid interface control unit 11 is inserted and the solid-liquid interface control unit 11 is arranged directly above the solid-liquid interface inside the pit 1 and the solid-liquid interface arranged directly above the solid-liquid interface in the arrangement step S5. A shape control step S6 for controlling the shape of the solid-liquid interface by heating the solid-liquid interface by the control unit 11 is included. The solid-liquid interface control unit 11 has at least one of a cylindrical control unit 6 that heats the central portion of the solid-liquid interface and a cylindrical control unit 7 that heats the peripheral portion of the solid-liquid interface. [Selection diagram] Fig. 1

Description

  The present disclosure relates to a single crystal growth method and a single crystal growth apparatus.

  The Czochralski method (rotational pulling method) is generally represented as a method of growing a single crystal. Another growth method is exemplified by the EFG method (Edge-defined Film-fed Growth Method: ribbon-like crystal growth method), a pulling method for pulling and solidifying a single crystal from a melt, vertical Bridgman method (vertical temperature gradient solidification) And the VGF method (Vertical Gradient Freeze Method: Vertical temperature gradient solidification method), there are a method of solidifying the melt in a crucible (directional solidification crystal growth method) and the like.

  Among these, the pulling method requires a space and a device for pulling the grown single crystal, and the size of the crystal growing apparatus must be increased, and the initial investment cost becomes large. On the other hand, in the Bridgman method and the like, since it is not necessary to pull up the grown single crystal, it is possible to miniaturize and simplify the crystal growth apparatus, and it is possible to suppress the initial investment cost.

  On the other hand, in the unidirectional Bridgman crystal growth method such as the vertical Bridgman method, the growth is carried out while solidifying in the crucible, but as the diameter of the crystal to be obtained becomes larger, the temperatures of the central part and the outer peripheral part in the crystal diameter The difference also increases. At that time, the solid-liquid interface shape during growth may be an extremely convex shape or a concave shape. When the solid-liquid interface shape is convex, cracks easily occur due to the internal stress difference of the crystal, and in the concave shape, dislocations from the seed crystal or dislocations generated at the time of growth concentrate in the crystal center and increase of crystal defects As a result, the yield of crystals tends to decrease.

  To address this problem, for example, Patent Document 1 proposes a method of growing a single crystal to obtain a desired solid-liquid interface shape by controlling the temperature by heating the bottom of the crucible by a heater provided on a support rod at the bottom of the crucible. ing. Moreover, in patent document 2, the temperature gradient of the center of a crucible and a wall surface is provided by providing shielding members, such as a heat insulating material, below the bottom of a crucible, and making it not receive to the influence of the radiant heat from the low temperature side in a crucible bottom by a shielding member. There is proposed a method of obtaining a desired solid-liquid interface shape by making the.

JP, 2011-195375, A JP, 2012-240895, A

  However, in the method of Patent Document 1, the bottom position of the temperature control is greatly different between the initial stage of growth immediately after seeding and the final stage of growth after lowering the pod. That is, since the temperature gradient is not constant, there is a high possibility that the solid-liquid interface shape may change during growth, and there is a problem that stable crystal growth can not be performed.

  In addition, the solid-liquid interface shape made up of the heat insulating material and the refractory placed in the growth furnace as in Patent Document 2 has a solid-liquid interface shape due to deterioration of the heat insulating material and the heater by repeating the growth. Since it collapses, expensive heat insulating materials and refractories have to be produced each time, resulting in high cost.

  The present disclosure aims to provide a single crystal growth method and a single crystal growth apparatus capable of controlling the solid-liquid interface shape during single crystal growth in a directionally solidified crystal growth method such as vertical Bridgman method or VGF method. I assume.

  A single crystal growth method according to one aspect of an embodiment of the present invention includes a melting step of melting a seed crystal and a single crystal raw material disposed inside a crucible, and a melt in the crucible generated in the melting step. A solid-liquid interface control unit inserted in the solid-liquid interface, and the solid-liquid interface controller disposed immediately above the solid-liquid interface in the crucible, and the solid-liquid interface disposed immediately above the solid-liquid interface in the arranging step. Controlling the shape of the solid-liquid interface by heating the solid-liquid interface by the control unit; and controlling the shape of the solid-liquid interface, the solid-liquid interface control unit heating the central part of the solid-liquid interface A method for growing a single crystal, comprising at least one of a portion and a cylindrical control portion for heating the peripheral portion of the solid-liquid interface.

  Similarly, in the single crystal growth method according to one aspect of the embodiment of the present invention, a crucible for containing a single crystal raw material, a heater disposed on the outer peripheral side of the crucible, and a solid-liquid interface inside the crucible directly above. And a solid-liquid interface control unit arranged to heat the solid-liquid interface to control the shape of the solid-liquid interface, the solid-liquid interface control unit heating a central portion of the solid-liquid interface It has at least one of a control part and a cylindrical control part which heats the peripheral part of the solid-liquid interface.

  According to the present disclosure, it is possible to provide a single crystal growth method and a single crystal growth apparatus capable of controlling the solid-liquid interface shape during single crystal growth in a direction solidification crystal growth method such as vertical Bridgman method or VGF method. Can.

It is a sectional view showing a schematic structure of a single crystal growing device concerning this embodiment. It is sectional drawing which shows the internal structure of the column-shaped control part in FIG. It is sectional drawing which shows the internal structure of the cylindrical control part in FIG. It is a flow chart of the single crystal growth method concerning this embodiment. It is a schematic diagram which shows shape control by the cylindrical control part in case solid-liquid interface is extremely convex shape. It is a schematic diagram which shows the shape control by a cylindrical control part in case solid-liquid interface is extremely concave shape.

  Hereinafter, embodiments will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same constituent elements in the drawings are denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  First, the process of having conceived the single crystal growth method and the single crystal growth apparatus according to the present embodiment will be described.

  The inventors of the present invention found no significant difference in the shape of the solid-liquid interface with crystals having a temperature difference of 3 inches or less having a small temperature difference within the crystal diameter during crystal growth, but as the crystal diameter increased for 4 inches or more, It can be seen that the temperature of the difference between the crystal diameter and the crystal diameter also increases, and the heater serving as the heat source is disposed to cover the crucible outer peripheral portion (crystal outer peripheral portion). It became clear that the solid-liquid interface had a convex shape by being smaller than the part.

  Starting from this knowledge, the present inventor has conducted intensive studies on a method of growing a single crystal. As a result, not only from the heater on the side but also from the top to the center of the crystal where heat from the crystal outer periphery is hard to be transmitted. Heat was also applied by a cylindrical heater to try to heat the central part of the crystal. As a result, the temperature difference in the crystal diameter became small, and the solid-liquid interface could be made into a convex shape close to flat.

  In addition, in cases where the furnace internal structure and crucible shape are different, it is also known that the solid-liquid interface has a concave shape due to the temperature in the center of the crystal becoming higher than the crystal outer periphery due to the effects of radiant heat from the crucible side. The The inventors of the present invention can form a solid-liquid interface near a flat convex shape by heating the crystal periphery by applying heat from above using a ring-shaped (cylindrical) heater fitted to the crystal periphery. did it. Also, if the desired solid-liquid interface shape can not be obtained with either a cylindrical or cylindrical heater, combine both the cylindrical and cylindrical heaters, or the heater output or the cylindrical and cylindrical position. By adjusting, the desired solid-liquid interface shape could be obtained. The present embodiment has been completed in this manner.

[Embodiment]
A single crystal growth apparatus 10 according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a cross-sectional view showing a schematic configuration of a single crystal growth apparatus 10 according to the present embodiment.

  The single crystal growth apparatus 10 according to the present embodiment basically has the same configuration as the conventional growth furnace for VGF method or vertical Bridgman method except that the solid-liquid interface control unit 11 is provided. .

  As shown in FIG. 1, in the single crystal growth apparatus 10, a cylindrical heater 5 is disposed inside a chamber and a heat insulating material (not shown). At the time of crystal growth, the inside of the chamber is filled with an inert gas such as argon gas, and a hot zone 9 is formed inside the heater 5. Further, the heater 5 has an upper heater 5a, a middle heater 5b, and a lower heater 5c along the upper side to the lower side in the height direction, and by adjusting the power supplied to these heaters 5a, 5b, 5c. , The temperature gradient in the hot zone 9 can be controlled. For example, the upper side of the heater 5 is high, and the lower side is a low temperature gradient.

  The crucible 1 is placed on a pedestal 2 placed in the hot zone. The gantry 2 can be configured to be vertically movable or rotatable by a support shaft 8 or the like. The crucible 1 is, for example, a bottomed container, and at the time of installation before crystal growth, the seed crystal 3 is disposed at the lower portion, and the single crystal raw material 4 is disposed on the seed crystal 3.

  A solid-liquid interface control unit 11 is provided above the hot zone 9. The solid-liquid interface control unit 11 heats the solid-liquid interface in the crucible 1 to control the shape of the solid-liquid interface. For example, when the crucible 1 is at the position of the highest temperature upper heater 5a at the initial stage of growth, the solid-liquid interface control unit 11 sinks into the molten single crystal raw material 4 inside the crucible 1 and is disposed right above the solid-liquid interface Are arranged to

  The solid-liquid interface control unit 11 includes a cylindrical control unit 6 that heats the central portion of the solid-liquid interface, and a cylindrical control unit 7 that heats the peripheral portion of the solid-liquid interface. The cylindrical control unit 6 and the cylindrical control unit 7 are arranged such that the lower surfaces thereof are on the same plane. Moreover, the cylindrical control part 6 and the cylindrical control part 7 are arrange | positioned in the concentric form which each central axis corresponds. The cylindrical control unit 6 and the cylindrical control unit 7 are preferably arranged such that the central axis coincides with the central axis of the crucible 1.

  The solid-liquid interface control unit 11 is configured to be movable in the vertical direction, for example, by a moving unit (not shown).

  FIG. 2 is a cross-sectional view showing an internal configuration of the cylindrical control unit 6 in FIG. FIG. 3 is a cross-sectional view showing an internal configuration of the cylindrical control unit 7 in FIG. In FIG. 2 and FIG. 3, (a) is a vertical sectional view in which the cutting line is in the vertical direction, and (b) is a horizontal sectional view in which the cutting line is in the horizontal direction.

  As shown in FIG. 2, the cylindrical control unit 6 has a cylindrical outer shell 6 a and a heating element 6 b housed inside the outer shell 6 a. The heating element 6b is, for example, a plurality of heating elements, and is disposed substantially equally to the bottom surface of the cylindrical outer shell 6a. For example, as shown in FIG. 2B, the heating elements 6b are arranged concentrically at substantially equal intervals around the center of the bottom surface.

  As shown in FIG. 3, the cylindrical control part 7 has the cylindrical-shaped outer shell 7a and the heat generating body 7b accommodated in the inside of this outer shell 7a. The outer shell 7a has an internal space between the inner peripheral surface and the outer peripheral surface, and the heat generating body 7b is accommodated in the internal space. The heating element 7b is, for example, a plurality of heating elements, and is disposed substantially equally to the bottom surface of the cylindrical outer shell 7a. For example, as shown in FIG. 3 (b), the heating elements 7b are arranged at substantially equal intervals along the circumferential direction of the annular inner space of the outer shell 7a.

  The outer shells 6a and 7a are formed of, for example, a material having high thermal conductivity, such as metal. The heating elements 6b, 7b are formed of, for example, carbon or molybdenum disilicide.

  A single crystal growth method according to the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart of the single crystal growth method according to the present embodiment. The single crystal growth method according to the present embodiment is basically the same as the conventional method for producing a single crystal by the unidirectional solidification method, except that the solid-liquid interface control unit 11 is used.

  In the single crystal growth method according to the present embodiment, first, crucible 1 is placed on pedestal 2 (step S1), and seed crystal 3 is accommodated from the opening at the top to the bottom of crucible 1 (step S2).

  A necessary amount of single crystal raw material 4 (for example, sapphire) obtained by crushing granular or single crystal from the opening at the top is disposed on the seed crystal 3 (step S3).

  Next, the heater 5 around the crucible 1 is operated to grow a single crystal inside the crucible 1. First, by using the heater 5, the crucible 1 in which the seed crystal 3 and the single crystal raw material 4 are stored is heated so that the temperature distribution is high at the upper side in the height direction and low at the lower side. In this state, the temperature in the furnace is raised until the seed crystal 3 melts to the upper half of the height direction, and seeding is performed (step S4: melting step). At the time of crystal growth, the inside of the furnace is inert atmosphere using argon gas.

  Next, the solid-liquid interface control unit 11 is inserted into the melt in the crucible 1 and brought close to the solid-liquid interface, and the solid-liquid interface control unit 11 is arranged directly above the solid-liquid interface (step S5: arrangement step) . For example, the solid-liquid interface control unit 11 is inserted into the crucible 1 by moving the solid-liquid interface control unit 11 closer to the crucible 1 from the upper side by moving means (not shown). The solid-liquid interface control unit 11 is disposed such that the central axes of the cylindrical control unit 6 and the cylindrical control unit 7 coincide with the central axis of the crucible 1.

  Next, the solid-liquid interface is heated by the solid-liquid interface control unit 11 disposed immediately above the solid-liquid interface to control the shape of the solid-liquid interface to a desired shape (step S6: shape control step).

  In step S6, depending on whether the shape of the solid-liquid interface generated by the heater 5 is convex or concave, the solid-liquid interface control section 11 solidifies using one of the cylindrical control section 6 and the cylindrical control section 7. Heat the liquid interface. For example, when the shape of the solid-liquid interface is an extremely convex shape, heating to the central portion of the solid-liquid interface by the cylindrical control unit 6 can control the solid-liquid interface having a desired convex shape. In addition, when the shape of the solid-liquid interface is an extremely concave shape, by heating the outer peripheral portion of the solid-liquid interface by the cylindrical control unit 7, it is possible to control the solid-liquid interface with a desired convex shape.

  Depending on whether the shape of the solid-liquid interface generated by the heater 5 is convex or concave, one of the cylindrical control unit 6 and the cylindrical control unit 7 of the solid-liquid interface control unit 11 is heated in advance It is also good. If the shape of the solid-liquid interface generated by the heater 5 is not a convex shape or a concave shape but a desired convex shape, heating of the solid-liquid interface by the solid-liquid interface control unit 11 is not performed in this step. May be

  Next, while maintaining the temperature gradient in the furnace, the crucible 1 is lowered downward using the support shaft 8 of the pedestal 2 to solidify all the melt, and then cooling is performed at a predetermined speed (step S7 ).

  Next, after confirming that the temperature in the furnace has reached about room temperature, the crucible 1 containing the grown single crystal is removed from the pedestal 2 and the grown single crystal is taken out from the upper opening of the crucible 1 (step S8).

  The effects of the present embodiment will be described with reference to FIGS. 5 and 6. FIG. 5 is a schematic view showing shape control by the cylindrical control unit 6 when the solid-liquid interface has an extremely convex shape. FIG. 6 is a schematic view showing shape control by the cylindrical control unit 7 when the solid-liquid interface has an extremely concave shape.

  As shown in FIG. 5, if the shape of the solid-liquid interface formed by the heater 5 in step S4 is an extremely convex shape, the temperature of the crystal central portion is lower than that of the crystal outer peripheral portion. For this reason, the temperature difference between the central portion and the outer peripheral portion of the crystal is alleviated by bringing the cylindrical control portion 6 heated to the central portion of the crystal closer to the solid-liquid interface, and a solid liquid interface with a convex shape close to flat is obtained. Be

  As shown in FIG. 6, if the shape of the solid-liquid interface formed by the heater 5 at step S4 is an extremely concave shape, the temperature of the crystal outer peripheral portion is lower than that of the crystal central portion contrary to the convex shape of FIG. . For this reason, the temperature difference between the crystal central portion and the outer peripheral portion is alleviated by bringing it close to the cylindrical control portion 7 heated to the crystal outer peripheral portion, and a convex-shaped solid-liquid interface similar to a flat can be obtained similarly.

  It is also possible to form a desired solid-liquid shape by combining both the cylindrical control unit 6 and the cylindrical control unit 7 or adjusting the heating output and the distance from the solid-liquid interface.

  As described above, in the present embodiment, by heating the solid-liquid interface by the solid-liquid interface control unit 11, it is possible to arbitrarily control the solid-liquid interface shape during single crystal growth in the unidirectional solidification crystal growth method. Become. By controlling the solid-liquid interface shape to a desired shape by the solid-liquid interface control unit 11 at the initial stage of growth, the growth can be performed with a substantially constant solid-liquid interface shape from the initial stage of growth to the final stage. Thereby, a crystal with small internal stress and few crystal defects can be stably obtained. In addition, since it is possible to cope with the case where the solid-liquid interface shape is broken due to the deterioration with time of the heat insulating material and the heater, the life of the heat insulating material and the heater can be extended, leading to cost reduction.

  Further, in the arranging step S4, the central axes of the cylindrical control unit 6 and the cylindrical control unit 7 are arranged to coincide with the central axis of the crucible 1. As a result, the cylindrical control unit 6 can accurately heat the crystal central portion, and the cylindrical control unit 7 can accurately heat the crystal outer peripheral portion, so that the solid-liquid interface can be controlled to a more desired shape.

  The cylindrical control unit 6 and the cylindrical control unit 7 respectively have outer shells 6a and 7a, and heating elements 6b and 7b housed inside the outer shells 6a and 7a. As a result, it is possible to prevent the heating elements 6b and 7b from directly touching and reacting with the crystal melt. Further, since the heat generated by the heating elements 6b and 7b is radiated through the outer shells 6a and 7a, the temperature distribution on the surfaces of the cylindrical control unit 6 and the cylindrical control unit 7 can be made more uniform.

  The solid-liquid interface control unit 11 may be configured to have only one of the cylindrical control unit 6 and the cylindrical control unit 7.

  Hereinafter, the present invention will be described in detail using an example of sapphire growth.

Example 1
Using the single crystal growth apparatus 10 shown in FIG. 1, single crystals were grown in the procedure of the single crystal growth method shown in FIG.

  Size (outside diameter 150 mm, height 400 mm, inside diameter 110-130 mm, taper angle 2 ° of outlet) consisting of Mo (molybdenum), W (tungsten) or an alloy of Mo 50% and W 50% We prepared bowl 1 of. The crucible 1 was placed on the pedestal 2 and the seed crystal 3 having an outer diameter of 110 mm and a height of 30 mm was housed at the bottom of the crucible 1. A necessary amount of single crystal raw material 4 obtained by grinding granules or crystals was placed thereon.

  There was a heater 5 made of carbon around the crucible 1, and the heater 5 was maintained so that the temperature distribution was high at the top and low at the bottom, and the inside of the furnace was performed in an inert atmosphere using argon gas. In this state, the crucible 1 was raised so that the single crystal raw material 4 and the seed crystal 3 were melted to about half the temperature in the furnace, and seeding was performed.

  From there, the solid-liquid interface control unit 11 according to the present embodiment was heated in advance, and was slowly inserted into the melt in the crucible 1 and brought close to the vicinity of the solid-liquid interface. This time, it is made of carbon in order to control the extremely convex shape (35 mm in height from the crystal outer peripheral part to the crystal central part) to be a flat convex shape (5 to 10 mm in height from the crystal outer peripheral part to the crystal central part) The cylindrical control part 6 (cylindrical diameter φ 50 mm) having the heating element 6b inside was used.

  After that, the crucible 1 is lowered at a speed of 5 mm / h for the purpose of growing, but the cylindrical control unit 6 is fixed at the same position as the seeding. After the crucible 1 was lowered to a predetermined position and all the melt was solidified, cooling was performed at a rate of 50 ° C./h. At the same time, the heating output of the cylindrical control unit 6 was dropped and moved up to a predetermined position. After confirming the temperature which can be taken out, the crystal was taken out from the crucible 1 and processed into a wafer shape so that the solid-liquid interface shape at the seeding position could be confirmed by X-ray topography. Twenty lots of such single crystals were grown, the height of the solid-liquid interface from the crystal end to the crystal center was measured, and the incidence of cracks was calculated.

(Comparative example 1)
Twenty lots of single crystals are grown by the same method as in Example 1 except that the shape of the solid-liquid interface is not controlled using solid-liquid interface controller 11 (cylindrical controller 6), and the crystal edge The height of the solid-liquid interface from the part to the central part of the crystal was measured to calculate the incidence of cracks.

What compared the solid-liquid interface height and crack generation rate of Example 1 and Comparative Example 1 is shown in Table 1.

(Example 2)
A cylindrical control unit having a carbon heating element 7b in order to control the solid-liquid interface to have an extremely concave shape with a convex shape close to a flat (5 to 10 mm in height from the crystal outer peripheral portion to the crystal central portion) The single crystal was grown in the same manner as in Example 1 except that 7 was used. Areas of the initial stage of growth, the middle stage and the last stage were processed into a wafer shape with respect to a crystal length of 250 mm, and EPD (dislocation density) was calculated.

(Comparative example 2)
The single crystal is grown in the same manner as in Example 2 except that the shape of the solid-liquid interface is not controlled using the solid-liquid interface controller 11 (cylindrical controller 7), and the crystal length is 250 mm. On the other hand, areas in the initial stage of growth, in the middle and in the last stage were processed into wafers, and EPD (dislocation density) was calculated.

What compared the solid-liquid interface height and dislocation density of Example 2 and Comparative Example 2 is shown in Table 2.

(Evaluation)
Comparative Example 1 (controlled) in Table 1 has a solid-liquid interface height of 40 mm and a crack generation rate of 20%, while Example 1 (controlled) has a solid-liquid interface height of 8 mm and cracked The incidence was 5%. As the solid-liquid interface height indicates, the difference in temperature between the crystal end and the inside is large in Comparative Example 1, and the internal stress of the crystal is also large, and it is considered that cracks easily occur.

  Table 2 shows the results of investigation of dislocation density. In the initial stage of the growth, dislocations propagated from the seed crystal and dislocations caused by seeding are generated, so no difference is observed between Comparative Example 2 (with no control) and Example 2 (with control). In the middle stage and the last stage, in Comparative Example 2, the dislocation density tends to gradually increase. The factor is that the solid-liquid interface has a concave shape, and it is believed that the dislocations lurking at the outer periphery of the crystal, which were not seen in the initial stage of the growth, gather in the central part by crystal growth and the dislocation density increases. On the other hand, in Example 2, since the solid-liquid interface has a convex shape, dislocations fall out to the outer peripheral part, so it is considered that the dislocation density is reduced.

  From the results shown in Examples 1 and 2 and Comparative Examples 1 and 2, according to the present embodiment, the method of heating the solid-liquid interface at the initial stage of growth using the solid-liquid interface control unit 11 is simple in the unidirectional solidification crystal growth method. It has been shown to be extremely effective in that the solid-liquid interface shape during crystal growth can be arbitrarily controlled. In addition, single crystal cracks are generated when the solid-liquid interface shape during growth becomes an extremely convex shape, and the dislocation density of the single crystal increases when the solid-liquid interface shape during growth becomes an extremely concave shape. It has been shown that it is possible to suppress the reduction of the yield of single crystals.

  The present embodiment has been described above with reference to the specific example. However, the present disclosure is not limited to these specific examples. Those appropriately modified in design by those skilled in the art are also included in the scope of the present disclosure as long as the features of the present disclosure are included. The elements included in the above-described specific examples, and the arrangement, conditions, and shapes thereof are not limited to those illustrated, but can be appropriately modified. The elements included in the above-described specific examples can be appropriately changed in combination as long as no technical contradiction arises.

Reference Signs List 1 3 seed crystal 4 single crystal raw material 5 heater 10 single crystal growth apparatus 11 solid-liquid interface control unit 6 cylindrical control unit 6a outer shell 6b heating element 7 cylindrical control unit 7a outer shell 7b heating element

Claims (5)

A melting step of melting a seed crystal and a single crystal raw material disposed inside the crucible;
Placing a solid-liquid interface control unit in the melt in the crucible generated in the melting step, and arranging the solid-liquid interface control unit directly above the solid-liquid interface in the crucible;
A shape control step of controlling the shape of the solid-liquid interface by heating the solid-liquid interface by the solid-liquid interface controller disposed immediately above the solid-liquid interface in the disposing step;
Including
The single crystal growth method, wherein the solid-liquid interface control unit includes at least one of a cylindrical control unit that heats a central portion of the solid-liquid interface and a cylindrical control unit that heats a peripheral portion of the solid-liquid interface. In the arranging step, central axes of the cylindrical control unit and the cylindrical control unit are arranged to coincide with a central axis of the weir.
A method of growing a single crystal according to claim 1. The cylindrical control unit and the cylindrical control unit have an outer shell and a heating element housed inside the outer shell.
The single crystal growth method according to claim 1. The heating element is carbon or molybdenum disilicide.
The single crystal growth method according to claim 3. A weir containing single crystal raw materials,
A heater disposed on an outer peripheral side of the crucible;
A solid-liquid interface control unit disposed immediately above the solid-liquid interface inside the crucible and heating the solid-liquid interface to control the shape of the solid-liquid interface;
Equipped with
The solid-liquid interface control unit includes at least one of a cylindrical control unit that heats a central portion of the solid-liquid interface and a cylindrical control unit that heats a peripheral portion of the solid-liquid interface.
Single crystal growth system.