JP2016020306A - Seed crystal holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a seed crystal holder, a seed crystal holder, a crystal growth apparatus, and a crystal growth method that suppress peeling of a seed crystal from a holding member.SOLUTION: A manufacturing method of a seed crystal holder includes a preparation step for preparing a holding member 2 made of carbon and a seed crystal 3 made of silicon carbide having a top face 3A larger than a bottom face 2A of the holding member 2, a fixing step for fixing the top face 3A of the seed crystal 3 to the bottom face 2A of the holding member 2, an arrangement step for arranging silicon particles 16 at the part of the top face 3A of the seed crystal 3 protruding from the holding member 2 so that the particles 16 contact a side face 2B of the holding member 2, a heating step for heating the holding member 2 and the particles 16 to a temperature higher than the melting point of silicon, and a bonding step for bonding the seed crystal 3 to the holding member 2 using the melted particles 16.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for producing a seed crystal holding body in which a seed crystal is bonded to a holding member, a seed crystal holding body, a crystal growth apparatus using the seed crystal holding body, and a crystal growing using the seed crystal holding body. The present invention relates to a crystal growth method.

  As a crystal currently attracting attention, there is silicon carbide (SiC) which is a compound of carbon and silicon. Silicon carbide has a wider band gap than silicon, has a high electric field strength that leads to dielectric breakdown (good withstand voltage characteristics), high thermal conductivity, high heat resistance, and excellent chemical resistance. In addition, it attracts attention because of various advantages such as excellent radiation resistance. Fields of interest for silicon carbide are wide, for example, heavy electricity including nuclear power, transportation including automobiles and aviation, home appliances, and space. A single crystal of silicon carbide is manufactured by a solution growth method as described in Patent Document 1, for example.

JP 2000-264790 A

  In the research and development of crystal growth made of silicon carbide, it was difficult to fix the single crystal and the seed crystal grown on the lower surface of the seed crystal to the holding member. The present invention has been devised in view of such circumstances, and a method for producing a seed crystal holding body capable of stably fixing a seed crystal to a holding member, a seed crystal holding body, and the use thereof It is an object of the present invention to provide a crystal growth apparatus and a crystal growth method.

  The method for producing a seed crystal holding body of the present invention includes a preparation step of preparing a holding member made of carbon and a seed crystal made of silicon carbide having an upper surface larger than the lower surface of the holding member, and the holding member A fixing step of fixing the upper surface of the seed crystal to a lower surface, and an arrangement step of arranging silicon particles in contact with a side surface of the holding member in a portion of the upper surface of the seed crystal that protrudes from the holding member And a heating step of heating the seed crystal, the holding member and the particles to a temperature higher than the melting point of silicon, and a bonding step of bonding the seed crystal to the holding member with the molten particles.

  The seed crystal holding body of the present invention has carbon as a main component, a holding member having a bonding region made of silicon carbide on the lower surface, and made of silicon carbide so that the upper surface is in contact with the bonding region on the lower surface of the holding member. And a seed crystal disposed on the surface.

  The crystal growth apparatus according to the present invention includes a crucible, a melt located in the crucible, a carbon-based bonding region that is set so as to be movable in the vertical direction in the crucible, and has a lower surface made of silicon carbide. A holding member that is present, and a seed crystal holding body that has a seed crystal that is made of silicon carbide and has an upper surface disposed in contact with the bonding region of the lower surface of the holding member.

The crystal growth method of the present invention includes a holding member mainly composed of carbon and having a bonding region made of silicon carbide on the lower surface, and made of silicon carbide so that the upper surface is in contact with the bonding region on the lower surface of the holding member. A step of preparing a seed crystal holder having a seed crystal disposed; and bringing the lower surface of the seed crystal into contact with a silicon carbide melt in a crucible and pulling the holding member upward, thereby And growing a silicon carbide crystal on the lower surface of the melt from the melt.

  According to the method for manufacturing a seed crystal holder of the present invention, a seed crystal holder in which the seed crystal is firmly fixed to the holding member can be manufactured. As a result, even when a crystal is grown on the lower surface of the seed crystal, the seed crystal can be hardly separated from the holding member.

  Further, according to the seed crystal holder, crystal growing apparatus and crystal growing method of the present invention, since the seed crystal is firmly fixed to the holding member, the holding member can be used even when the crystal is grown on the lower surface of the seed crystal. The seed crystal can be made difficult to peel off.

It is sectional drawing which shows an example of embodiment of the crystal growth apparatus which concerns on embodiment of this invention. It is a figure which shows the seed crystal holding body which concerns on embodiment of this invention, (a) is sectional drawing to which one part was expanded, (b) is the figure seen through plane from the lower surface side of a seed crystal. It is a figure which shows the modification of the seed-crystal holding body of FIG. 2, is an expanded sectional view which expanded a part, and a graph is a figure which shows how silicon carbide is distributed. It is a figure which shows the modification of the seed crystal holding body of FIG. 2, and is the expanded expanded sectional view. It is a figure which shows the modification of the seed crystal holding body of FIG. 2, (a) is sectional drawing to which one part was expanded, (b) is the figure seen in plane from the lower surface side of the seed crystal. It is a figure which shows the modification of the seed crystal holding body of FIG. 2, (a) is sectional drawing to which one part was expanded, (b) is the figure seen in plane from the lower surface side of the seed crystal. It is a figure which shows the modification of the seed crystal holding body of FIG. 2, and is the expanded sectional view which expanded a part. It is a figure which shows the modification of the seed crystal holding body of FIG. 2, (a) is sectional drawing to which one part was expanded, (b) is the figure seen in plane from the lower surface side of the seed crystal. It is a figure explaining 1 process of the manufacturing method of the seed crystal holding body which concerns on the 1st Embodiment of this invention, and is the expanded sectional view which expanded a part. It is a figure explaining 1 process of the manufacturing method of the seed crystal holding body of FIG. 9, and is the expanded sectional view which expanded a part. It is a figure explaining 1 process of the manufacturing method of the seed crystal holding body of FIG. 9, and is the expanded sectional view which expanded a part. It is a figure explaining 1 process of the manufacturing method of the seed crystal holding body of FIG. 9, and is the expanded sectional view which expanded a part. It is a figure explaining 1 process of the modification of the manufacturing method of the seed crystal holding body which concerns on embodiment of this invention, and is the expanded sectional view which expanded a part. It is the expanded sectional view which expanded a part showing the seed crystal holder manufactured by the manufacturing method of the seed crystal holder concerning a 2nd embodiment of the present invention.

<Seed crystal holder and method for producing seed crystal holder>
[Seed crystal holder]
An embodiment of a seed crystal holder according to the present invention will be described with reference to the drawings. The seed crystal holder 1 is composed of a holding member 2 and a seed crystal 3. The seed crystal holder 1 is used in a crystal growth apparatus 4 as shown in FIG. First, the crystal growth apparatus 4 will be described.

  The crucible 5 is disposed inside the crucible container 6. The crucible container 6 has a function of holding the crucible 5. A heat insulating material 7 is disposed between the crucible container 6 and the crucible 5. This heat insulating material 7 surrounds the crucible 5. The heat insulating material 7 suppresses heat radiation from the crucible 5 and contributes to maintaining the temperature of the crucible 5 stably.

  The crucible 5 has a function as a vessel for melting the raw material of the silicon carbide single crystal to be grown inside. In the present embodiment, the single crystal raw material (carbon and silicon) is melted in the crucible 5 and stored as the melt 8. In the present embodiment, a solution growth method is employed, and crystals are grown by creating a thermal equilibrium state inside the crucible 5.

  The crucible 5 is heated by the heating mechanism 9. The heating mechanism 9 of the present embodiment employs an electromagnetic heating method in which the crucible 5 is heated by electromagnetic waves, and includes a coil 10 and an AC power supply 11. The crucible 5 is made of a material mainly composed of carbon (graphite), for example.

  A melt 8 is disposed inside the crucible 5. In the melt 8, carbon and silicon, which are elements constituting the crystal of silicon carbide to be grown, are melted as a solvent. The solubility of the element that becomes the solute increases as the temperature of the element that becomes the solvent increases. For this reason, since the temperature of the seed crystal 3 is slightly lower than the temperature of the melt 8, the temperature of the melt 8 in which many solutes are dissolved in the solvent at a high temperature is lowered in the vicinity of the seed crystal 3. The solute begins to deposit at the boundary of thermal equilibrium. In the solution growth method employed in this embodiment, the crystal is grown on the lower surface 3B of the seed crystal 3 by utilizing precipitation due to this thermal equilibrium.

  The coil 10 is formed of a conductor and is wound so as to surround the periphery of the crucible 5. The AC power supply 11 is for flowing an AC current through the coil 10, and the heating time up to the set temperature in the crucible 5 can be shortened by using an AC current having a high frequency.

  In the present embodiment, the crucible 5 is heated as follows. First, an electric current is passed through the coil 10 using the AC power source 11 to generate an electromagnetic field in the space including the heat insulating material 7. Next, an induced current flows through the crucible 5 by this electromagnetic field. The induced current flowing through the crucible 5 is converted into thermal energy by various losses such as Joule heat generation due to electric resistance and heat generation due to hysteresis loss. That is, the crucible 5 is heated by the heat loss of the induced current. The electromagnetic field may generate heat by causing an induced current to flow through the melt 8 itself. In this way, when the melt 8 itself generates heat, the crucible 5 itself does not need to generate heat.

  In the present embodiment, an electromagnetic heating method is employed as the heating mechanism 9, but heating may be performed using other methods. The heating mechanism 9 can employ other methods such as a method of transferring heat generated by a heating resistor such as carbon. When this heat transfer type heating mechanism is adopted, a heating resistor is disposed between the crucible 5 and the heat insulating material 7.

  The seed crystal 3 is supplied to the melt 8 of the crucible 5 by the transport mechanism 12. The transport mechanism 12 also has a function of carrying out crystals grown from the melt 8. The transport mechanism 12 includes a holding member 2 and a power source 13. The holding member 2 carries in and out the seed crystal 3 and the crystal grown on the lower surface 3B of the seed crystal 3. The seed crystal 3 is attached to the lower end surface 2A of the holding member 2, and the movement of the holding member 2 is controlled in the vertical directions D1 and D2 by the power source 13. In the present embodiment, the D1 direction means a downward direction on the physical space, and the D2 direction means an upward direction on the physical space.

In the crystal growing apparatus 4, an AC power source 11 of the heating mechanism 9 and a power source 13 of the transport mechanism 12 are included in the control unit 14.
Connected to and controlled. That is, in the crystal growing device 4, the heating and temperature control of the melt 8 and the carry-in / out of the seed crystal 3 are controlled by the control unit 14 in conjunction with each other. The control unit 14 includes a central processing unit and a storage device such as a memory, and is composed of, for example, a known computer.

  The lower surface 3B of the seed crystal 3 fixed to the lower end surface 2A of the holding member 2 can be brought into contact with the melt 8 to grow a crystal on the lower surface 3B. Next, the crystal holder 1 composed of the seed crystal 3 and the holding member 2 will be described in detail.

  As shown in FIG. 2A, the holding member 2 has the upper surface 3A of the seed crystal 3 fixed to the lower end surface 2A. Here, FIG. 2A is an enlarged view of a part including the seed crystal 3 and the holding member 2. The holding member 2 should just have 2 A of lower end surfaces. The lower end surface 2A has a polygonal shape such as a quadrangular shape or a planar view shape such as a circular shape. The holding member 2 has a three-dimensional shape such as a rod shape such as a polygonal column shape or a cylindrical shape, or a rectangular parallelepiped shape.

  The holding member 2 is made of a material mainly composed of carbon. As the holding member 2, for example, a polycrystal of carbon or a fired body obtained by firing carbon can be used. When the holding member 2 is made of a carbon polycrystal or fired body, the porosity in the holding member 2 is high. The porosity inside the holding member 2 can be changed, for example, by adjusting the firing conditions. As a method for calculating the porosity (%), for example, a calculation formula “porosity (%) = volume ÷ mass × 100” can be used.

  The area of the lower end surface 2A of the holding member 2 may be larger than the upper surface 3A of the seed crystal 3, may be the same area as the upper surface 3A of the seed crystal 3, or may be smaller than the upper surface 3A of the seed crystal 3. . In the present embodiment, the lower end surface 2A of the holding member 2 is smaller than the area of the upper surface 3A of the seed crystal 3. When the area of the lower end surface 2A of the holding member 2 is equal to or larger than the area of the upper surface 3A of the seed crystal 3, the heat of the seed crystal 3 can be easily released from the holding member 2.

  A joining region 2 </ b> A ′ made of silicon carbide exists on the lower end surface 2 </ b> A of the holding member 2. FIG. 2B is a plan view of the lower end surface 2A of the holding member 2 seen from the seed crystal 3 side.

  The joining region 2A 'of the holding member 2 may be located over the entire lower end surface 2A, or may be located in a part of the lower end surface 2A. When the joining region 2A 'is located over the entire lower end surface 2A, the holding member 2 and the seed crystal 3 can be made difficult to peel off.

  On the other hand, when the bonding region 2A 'is located at a part of the lower end surface 2A, the area occupied by the bonding region 2A' with respect to the entire lower end surface 2A may be set as appropriate. The joining region 2A 'does not necessarily have a specific planar shape, but is arranged so as to have a planar shape such as a circular shape or an annular shape. When the joining region 2A ′ is a part of the lower end surface 2A, when the seed crystal 3 is fixed to the lower end surface 2A of the holding member 2, the plane of the seed crystal 3 (a plane represented by the D3 direction and the D4 direction) Strain or stress in the direction can be relaxed. Thereby, the flatness of the lower surface 3B of the seed crystal 3 can be maintained, and the crystal growing on the lower surface 3B of the seed crystal 3 can be made less likely to contain dislocations.

  In the present embodiment, the planar shape is provided in an annular shape so that the joining region 2 </ b> A ′ is a part of the lower end surface 2 </ b> A of the holding member 2. Specifically, the joining region 2 </ b> A ′ is disposed so as to include the outer peripheral portion 2 </ b> AA of the lower end surface 2 </ b> A of the holding member 2. This does not exclude the case where the joining region 2A 'is arranged so as not to include the outer peripheral portion 2AA of the lower end surface 2A.

Bonding region 2A ′ may be one in which carbon in lower end surface 2A of holding member 2 is chemically changed to silicon carbide, or silicon carbide crystals may be formed in pores located near lower end surface 2A. Alternatively, it may be a silicon carbide crystal located between the lower end surface 2A and the upper surface 3A of the seed crystal 3. That is, it is only necessary that the lower end surface 2A of the holding member 2 and the upper surface 3A of the seed crystal 3 are joined by silicon carbide.

  In the present embodiment, the holding member 2 and the seed crystal 3 are bonded (fixed) via a bonding region 2A ′ made of silicon carbide. Since the seed crystal 3 is bonded to the holding member 2 via silicon carbide, the melting point (2730 ° C.) of silicon carbide is higher than the temperature of the melt 8. Even when approaching, the seed crystal 3 and the holding member 2 can be stably fixed. That is, the bonding strength between the seed crystal 3 and the holding member 2 can be maintained even in a high temperature atmosphere near the melt 8.

  As a result, even when the crystal is grown greatly on the lower surface 3B of the seed crystal 3, the seed crystal 3 can be made difficult to peel from the holding member 2. Thereby, the crystal grown on the lower surface 3B of the seed crystal 3 can be made larger than the conventional holding method.

  In the conventional seed crystal holder, the holding member and the seed crystal are joined only with the adhesive. Therefore, in the high temperature atmosphere near the melt, a part of the adhesive is vaporized, and the bonding strength between the seed crystal and the holding member is reduced. As a result, when the crystal grown on the lower surface of the seed crystal was enlarged, the weight of the seed crystal and the grown crystal could not be supported, and the seed crystal was peeled off from the holding member.

  Further, in the present embodiment, the holding member 2 and the seed crystal 3 are bonded via a bonding region 2A ′ made of silicon carbide. Therefore, the thermal conductivity (thermal conductivity 200 to 350 [W / m / K]) of silicon carbide constituting the joining region 2A ′ is the thermal conductivity of carbon (thermal conductivity 168 [W / m / K]). Therefore, the heat dissipation of the seed crystal 3 can be improved, a temperature difference can be created at the interface between the lower surface 3B of the seed crystal 3 and the melt 8, and the crystal is formed on the lower surface 3B of the seed crystal 3. It can be easily grown.

(Variation 1 of seed crystal holder)
As shown in FIG. 3, the bonding area 2 </ b> A ′ has a silicon carbide ratio that increases from the center of the lower end surface 2 </ b> A of the holding member 2 toward the outer peripheral portion 2 </ b> AA. Here, the case where an annular joining region 2A ′ is included so as to include the outer peripheral portion 2AA as shown in FIG. 3 is also included.

  The abundance ratio of silicon carbide may gradually increase, for example, from the center of the lower end surface 2A toward the outer periphery 2AA, and the abundance ratio of the region near the outer periphery 2AA increases with respect to the region near the center. It may be. As a method for measuring the abundance ratio of silicon carbide, for example, SIMS method or XPS method can be used.

  Thus, as the abundance ratio of silicon carbide increases from the center of the lower end surface 2A toward the outer peripheral portion 2AA, the area of the junction region 2A ′ can be increased, and the upper surface 3A of the seed crystal 3 can be increased. The strength joined to the holding member 2 can be adjusted. As a result, strain or stress generated in the seed crystal 3 can be suppressed while maintaining the bonding strength.

(Variation 2 of seed crystal holder)
As shown in FIG. 4, the holding member 2 may further include silicon carbide on the side surface 2B. The silicon carbide existing region 2B ′ present on the side surface 2B of the holding member 2 may be, for example, one in which the carbon of the holding member 2 is chemically changed to silicon carbide, or silicon carbide crystals are formed in the pores of the holding member 2. May be located. Since silicon carbide is present on the side surface 2B of the holding member 2 in this manner, the thermal conductivity of silicon carbide is higher than that of carbon, so that the heat dissipation of the holding member 2 can be improved. As a result, heat is easily radiated from the holding member 2, the temperature of the seed crystal 3 can be lowered, and a temperature difference with the melt 8 can be generated. As a result, the crystal can be easily grown on the lower surface 3B of the seed crystal 3.

(Variation 3 of seed crystal holder)
As shown in FIG. 5, the holding member 2 may have a through hole 15 that penetrates from the lower end surface 2 </ b> A to the upper end surface 2 </ b> C. The through hole 15 is provided so that the upper surface 3A of the seed crystal 3 is exposed, and the width Lh is set to be, for example, not less than 0.5 cm and not more than 5 cm. The shape of the through hole 15 in plan view can be set as appropriate, and can be provided, for example, in a polygonal shape or a circular shape.

  Since the through hole 15 is provided in the holding member 2, the contact area between the holding member 2 and the seed crystal 3 can be reduced, and strain or stress generated in the seed crystal 3 can be reduced. Further, in the fixing step described later, when the holding member 2 and the seed crystal 3 are fixed and heated with the adhesive 17, even when the material contained in the adhesive 17 is vaporized, it can be easily removed from the through hole 15. Both can be stably fixed.

(Modification 4 of seed crystal holder)
As shown in FIG. 6, the holding member 2 may have a joining region 2 </ b> A ′ that is a part of the lower end surface 2 </ b> A. Even in a part of the lower end surface 2A, the strain or stress generated in the seed crystal 3 can be relaxed by fixing the seed crystal 3 with a part of the outer peripheral portion 2AA of the holding member 2 in this way. In addition, since the seed crystal 3 is fixed by a part of the outer peripheral portion 2AA of the holding member 2, the growth region 2A ″ in which the distortion of the seed crystal 3 is reduced can be made large. Of the crystals grown to 3A, a crystal with reduced dislocations caused by strain of the seed crystal 3 can be enlarged.

(Variation 5 of seed crystal holder)
The holding member 2 may be set so that the joining region 2A ′ is, for example, 10% or less with respect to the area of the lower end surface 2A. By reducing the area of the joining region 2A ′ relative to the lower end surface 2A of the holding member 2, strain or stress generated in the seed crystal 3 can be relaxed.

  Further, by arranging such a junction region 2A ′ so as to include the vicinity of the center of the upper surface 3A of the seed crystal 3 as shown in FIG. 7, the seed crystal 3 and the seed crystal 3 with respect to the junction region 2A ′. It is possible to suppress the weight of crystals grown on the lower surface 3 </ b> B from being concentrated in one direction.

  Further, at this time, as shown in FIG. 8, a holding member 2 having a through hole 15 may be used. In this case, silicon particles 16 are placed on the upper surface 3A of the seed crystal 3 in the through hole 15 in the arrangement step of the manufacturing method of the seed crystal holding body 1 of the first embodiment to be described later, and the heating step is performed. Manufactured by. Such a seed crystal holding body 1 is formed at a position (2A ′ in the drawing) where the joining region 2A ′ surrounds a region overlapping the through hole 15 when seen in a plan view. By placing the silicon particles 16 in the through holes 15 in this way, it is possible to prevent the melt 16 ′ from flowing to the lower surface 3B of the seed crystal 3 when the particles 16 are heated and melted. it can.

[Method for Producing Seed Crystal Carrier of First Embodiment]
A method for manufacturing the seed crystal holder 1 according to the first embodiment of the present invention will be described. The manufacturing method of the seed crystal holder 1 of the present embodiment includes a step of preparing a seed crystal, a fixing step of fixing the seed crystal to the holding member 2, an arrangement step of arranging silicon particles 16, a seed crystal 3, and a holding member 2. And a heating step for heating the particles 16 and a joining step for joining the seed crystal 3 to the holding member 2. Hereinafter, each process will be described in detail. Each member has the same content as the seed crystal holder 1,
The same reference numerals are given and the description thereof is omitted.

(Preparation process)
A seed crystal 3 having a holding member 2 made of carbon and an upper surface 3B larger than the lower end surface 2A of the holding member 2 and made of silicon carbide is prepared. The holding member 2 should just have carbon as a main component. The holding member 2 is set so that the lower end surface 2A is larger than the upper surface 3A of the seed crystal 3.

(Fixing process)
As shown in FIG. 9, the upper surface 3 </ b> A of the seed crystal 3 is fixed to the lower end surface 2 </ b> A of the holding member 2. As a method of fixing both, for example, it may be fixed by a jig, may be fixed by an adhesive, or the holding member 2 may be placed on the upper surface 3A of the seed crystal 3. In the present embodiment, the case of fixing with the adhesive 17 will be described. As the adhesive 17, for example, an adhesive containing carbon particles can be used.

  When fixing using the adhesive material 17, the adhesive material 17 is applied to a part of the upper surface 3 </ b> A of the seed crystal 3, and the lower end surface 2 </ b> A of the holding member 2 is placed on the adhesive material 17. Thereafter, the adhesive 17 is cured by applying heat to the adhesive 17. The heat given to the adhesive 17 is set to be 100 ° C. or more and 500 ° C. or less, for example. Thereby, the holding member 2 and the seed crystal 3 are temporarily fixed. In the present embodiment, the case of fixing using the adhesive 17 will be described.

Since the upper surface 3A of the seed crystal 3 is larger than the lower end surface 2A of the holding member 2 by fixing the seed crystal 3 to the holding member 2, as shown in FIG. 2 to have an exposed portion 3A ′ exposed from 2. The exposed portion 3A ′ may be set as appropriate, but may be set to be 1 mm ² or more and 10 cm ² or less, for example.

(Arrangement process)
Thereafter, as shown in FIG. 10, silicon particles 16 are arranged on the exposed portion 3A ′ of the upper surface 3A of the seed crystal 3 protruding from the holding member 2 so as to be in contact with the side surface 2B of the holding member 2.

As the silicon particles 16, particles having such a size that can be placed on the exposed portion 3A 'can be used. The number of particles 16 may be one or a group of particles composed of a plurality of particles 16. As the size of one particle 16, for example, a polycrystalline body containing silicon having a particle size of 0.5 mm or more and 5 cm or less can be used. When a particle group having a plurality of particles having a small particle diameter is used as the particle 16, each particle can easily come into contact with air, and the particles can be easily dissolved. On the other hand, when one particle having a large particle diameter is used, dissolution of the particles gradually proceeds, and it is possible to make it difficult to go around the lower surface 3B of the seed crystal 3 and to maintain the state of the lower surface 3B. .

  The particles 16 may be arranged so that at least a part of the side surface 2B of the holding member 2 is in contact. The contact between the particles 16 and the holding member 2 may be in the state before the heating step, and the efficiency of the joining step can be improved by bringing the particles 16 and the holding member 2 into contact with each other and passing through the heating step. . Therefore, even when the holding member 2 and the particles 16 are not in strict contact with each other, the case where the molten particles join the holding member 2 and the seed crystal 3 through the heating step is included in this embodiment. Is.

(Heating process)
Next, the seed crystal 3, the holding member 2, and the particles 16 are heated at a temperature higher than the melting point of silicon. The temperature for heating the seed crystal 3, the holding member 2, and the particles 16 may be any temperature that is higher than the melting point of silicon (1414 ° C.), and can be set to, for example, 1500 ° C. or higher. When the actual melting point of the silicon particles 16 is lower than the melting point of silicon due to impurities or the like, a temperature higher than the actual melting point may be used as the heating temperature.

  Thus, the particles 16 are dissolved by being heated at a temperature higher than that of silicon. As shown in FIG. 11, the melt 16 ′ in which the particles 16 are melted easily enters the inside through the pores of the holding member 2 and easily stays in the vicinity of the holding member 2 and the seed crystal 3.

(Joining process)
The seed crystal 3, the melt 16 ′, and the holding member 2 are cooled by the heating process while the melt 16 ′ in which the particles 16 are melted stays in the vicinity of the holding member 2 and the seed crystal 3. As a result, a crystal made of silicon carbide is formed inside the holding member 2, and this crystal is bonded to the seed crystal 3. In this way, the holding member 2 and the seed crystal 3 are joined to the lower end surface 2A ′ of the holding member 2 by the joining region 2A ′ made of silicon carbide and in contact with the seed crystal 3. Note that the area of the bonding region 2A ′ can be adjusted by adjusting the heating time and the amount of particles 16.

  Cooling of the seed crystal 3, the melt 16 ′ and the holding member 2 is, for example, natural cooling performed by stopping the heating of the particles 16, or forced cooling using a cooling group such as air cooling while stopping the heating of the particles 16. Can be used.

  In this way, the seed crystal holder 1 can be manufactured.

(Modification 1 of the manufacturing method of the seed crystal holding body of 1st Embodiment)
In the heating step, as shown in FIG. 13, at least one of the holding member 2 or the seed crystal 3 may be heated while being pressed toward the fixing portion between them. What is necessary is just to set the fixing | fixed part of the holding member 2 and the seed crystal 3 to the contact interface etc. of the lower end surface 2A of the holding member 2, and the upper surface 3A of the seed crystal 3.

  As means 18 for pressing at least one of the holding member 2 and the seed crystal 3, for example, a weight member heavier than the holding member 2 may be placed on the upper end surface 2C of the holding member 2, or held by a jig. The upper end surface 2C of the member 2 and the lower surface 3B of the seed crystal 3 can be fixed and pressed. By thus pressing at least one of the holding member 2 and the seed crystal 3 and heating the particles 16, the holding member 2 and the seed crystal 3 can be reliably fixed. Further, in the heating process, the melt 16 'enters between the holding member 2 and the seed crystal 3 and is pressed even when the relative position between the holding member 2 and the seed crystal 3 is easily displaced in the plane direction. The holding member 2 and the seed crystal 3 can be joined while maintaining a predetermined relative position.

(Variation 2 of the method for manufacturing the seed crystal holder of the first embodiment)
The heating step may be performed in an atmosphere mainly containing argon, nitrogen, or helium. In such an atmosphere, it is only necessary that the abundance ratio of any one of argon, nitrogen, and helium is larger than the abundance ratio of molecules other than these contained in the atmosphere.

  By performing the heating process in such an atmosphere, argon, nitrogen, or helium is a material that does not easily react with silicon, and thus the substance in the atmosphere is taken in as an impurity in the melt 16 ′ in which the particles 16 are melted. It can be made difficult.

[Method for Producing Seed Crystal Carrier of Second Embodiment]
A method for producing the seed crystal holder 1 ′ according to the second embodiment of the present invention will be described. The manufacturing method of seed crystal holding body 1 ′ of the present embodiment is the same as that of the first embodiment in that the holding member does not have to contain carbon as a main component, and the heating step is performed in an atmosphere mainly containing hydrocarbons. This is different from the method for manufacturing the seed crystal holder 1.

  The holding member 21 may be any material that does not dissolve in the heating process. For example, a material mainly composed of carbon, a metal material such as gold, molybdenum, or tantalum, or an inorganic material such as alumina can be used. Thus, since an inorganic material or the like can be used as the holding member 21, the selectivity of the material can be improved, and the productivity can be improved.

  Next, the heating step is performed mainly in an atmosphere containing hydrocarbons. Specifically, as the hydrocarbon, for example, a carbonized compound such as butane or propane can be used. When alkane, which is a chain hydrocarbon, is used among hydrocarbons, bonds between carbons can be easily broken in a high-temperature atmosphere, and reaction with silicon particles 16 can be facilitated.

  By performing the heating step in an atmosphere containing hydrocarbon in this way, the particles 16 arranged on the upper surface 31A of the seed crystal 31 are melted and combined with hydrocarbon carbon to form silicon carbide. Since this silicon carbide joins holding member 21 and seed crystal 3, seed crystal 31 is joined to holding member 21.

  In this embodiment, since the heating process is performed in an atmosphere containing hydrocarbons, the material selectivity of the holding member 21 can be expanded. That is, in order to further reduce the temperature of the seed crystal 31, a material having a good thermal conductivity or a material having a low thermal expansion coefficient can be selected, and productivity can be improved. In addition, when a material mainly composed of carbon is used as the holding member 21, in addition to the carbon of the holding member 21 and the particles 16 being combined, carbon in the atmosphere is easily taken into the particles 16, Silicon carbide can be easily contained in the melt 16 ′ in which the particles 16 are melted.

(Modification of the method for manufacturing the seed crystal holder of the second embodiment)
In the above-described embodiment, the heating step is performed in an atmosphere containing hydrocarbon. However, for example, the silicon particles 16 may be carbonized by another method. Specifically, a powder containing carbon may be placed on the silicon particles 16 after the arranging step. Thereafter, through a heating step, seed crystal 31 can be bonded to holding member 21 with silicon carbide interposed.

  Further, powder containing carbon may be mixed into the silicon particles 16, and when mixed, the particles 16 can be easily changed to silicon carbide when the particles 16 are melted. Further, the heating step may be performed in an atmosphere containing hydrocarbon, and in this case, the melt 16 'can be more easily changed to silicon carbide.

<Crystal growth apparatus and crystal growth method>
[Crystal growth equipment]
The crystal growth apparatus 4 according to the embodiment of the present invention includes a crucible 5, a melt 8, and a seed crystal holder 1. In addition, about the same content as the content demonstrated by the seed crystal holder 1, the same code | symbol is provided and the description is abbreviate | omitted.

  Since the crystal growth apparatus 4 of this embodiment has the seed crystal holder 1, the seed crystal 3 and the holding member 2 are stably fixed. Therefore, even when the crystal is greatly grown on the lower surface 3 </ b> B of the seed crystal 3, the seed crystal 3 is hardly separated from the lower end surface 2 </ b> A of the holding member 2. As a result, the crystal growing apparatus 4 can increase the size of the crystal to be grown and improve the productivity.

[Crystal growth method]
The crystal growth method according to the embodiment of the present invention includes a step of preparing a seed crystal holder and a step of growing a crystal. In addition, about the same content as the content mentioned above, while giving the same code | symbol, the description is abbreviate | omitted.

(Preparation process)
The holding member 2 is mainly composed of carbon and has a bonding region 2A ′ made of silicon carbide on the lower end surface 2A, and the upper surface 3A is in contact with the bonding region 2A ′ of the lower end surface 2A of the holding member 2. A seed crystal holding body 1 having a seed crystal 3 arranged is prepared.

(Crystal growth process)
Next, the lower surface 3 </ b> B of the seed crystal 3 is brought into contact with the silicon carbide melt 8 in the crucible 5. The lower surface 3B of the seed crystal 3 may be brought into contact with the melt 8 as long as a part of the lower surface 3B is in contact. For example, the seed crystal 3 is melted into the melt 8 until the upper surface 3A of the seed crystal 3 is immersed in the melt 8. You may put it in. Thereafter, a crystal of silicon carbide can be grown from the melt 8 on the lower surface 3B of the seed crystal 3 by pulling the holding member 2 upward (D2 direction). What is necessary is just to set the pulling-up speed of the holding member 2 with the growth rate of the crystal | crystallization growing on the lower surface 3B of the seed crystal 3, for example.

  In the crystal growth method of the present embodiment, since the crystal is grown on the lower surface 3B of the seed crystal 3 using the seed crystal holder 1, the holding member 2 is used even when the crystal growing on the lower surface 3B becomes large. It is difficult for the seed crystal 3 to peel off from the lower end surface 2A. As a result, productivity of crystals to be grown can be improved.

  In the above-described embodiments, the solution growth method has been described as an example. However, the present invention is a technique applicable to the sublimation method, and various modifications are appropriately made within the scope of the effects of the present invention. Can be anything.

1 Seed crystal holding body 2 Holding member 2A Lower end surface (lower surface)
2A 'Joining area 2AA Outer periphery 2B Side surface 2C Upper end surface (upper surface)
3 seed crystal 3A upper surface 3A 'exposed portion 3B lower surface 4 crystal growing apparatus 5 crucible 6 crucible container 7 heat insulating material 8 melt 9 heating mechanism
10 coils
11 AC power supply
12 Transport mechanism
13 Power source
14 Control unit
15 Through hole
16 particles
16 'melt
17 Adhesive
18 Pressing means

The seed crystal holding body of the present invention includes a holding member having a silicon carbide bonding region on a lower end surface, and an upper surface in contact with the bonding region on the lower end surface of the holding member. And
The joining region includes an edge of a lower end surface of the holding member and has an annular planar shape.

Claims (12)

A preparation step of preparing a holding member made of carbon and a seed crystal made of silicon carbide having an upper surface larger than the lower surface of the holding member;
A fixing step of fixing the upper surface of the seed crystal to the lower surface of the holding member;
An arrangement step of disposing silicon particles in contact with a side surface of the holding member on a portion of the upper surface of the seed crystal that protrudes from the holding member;
Heating the seed crystal, the holding member and the particles to a temperature higher than the melting point of silicon;
A method for producing a seed crystal holder, comprising a joining step of joining the seed crystal to the holding member with the melted particles.   The method for producing a seed crystal holding body according to claim 1, wherein in the heating step, heating is performed while pressing at least one of the holding member or the seed crystal toward the fixing portion of both.   The method for producing a seed crystal holder according to claim 1 or 2, wherein the heating step is performed in an atmosphere mainly containing argon, nitrogen, or helium.   The method for producing a seed crystal holding body according to any one of claims 1 to 3, wherein in the fixing step, the upper surface of the seed crystal is fixed to the lower surface of the holding member via an adhesive containing carbon particles. . A preparation step of preparing a holding member and a seed crystal made of silicon carbide having an upper surface larger than a lower surface of the holding member;
A fixing step of fixing the upper surface of the seed crystal to the lower surface of the holding member;
An arrangement step of arranging silicon particles in contact with a side surface of the holding member in a portion of the upper surface of the seed crystal that protrudes from the holding member;
A heating step of heating the seed crystal, the holding member and the particles to a temperature higher than the melting point of silicon in an atmosphere mainly containing hydrocarbons;
A method for producing a seed crystal holder, comprising a joining step of joining the seed crystal to the holding member with the melted particles. A holding member having carbon as a main component and a bonding region made of silicon carbide on the lower surface;
A seed crystal holder comprising a seed crystal made of silicon carbide and having an upper surface disposed in contact with the joining region of the lower surface of the holding member.   The seed crystal holder according to claim 6, wherein the joining region is present on an outer peripheral portion of the lower surface of the holding member.   The seed crystal holding body according to claim 6 or 7, wherein the bonding region has a silicon carbide content ratio that increases from the center of the lower surface of the holding member toward the outer periphery.   The seed crystal holder according to any one of claims 6 to 8, wherein the holding member further includes silicon carbide on a side surface.   The seed crystal holder according to claim 6, wherein the holding member has a hole penetrating from the lower surface to the upper surface. Crucible,
A melt located in the crucible;
The holding member, which is set to be movable in the vertical direction in the crucible, has carbon as a main component and has a bonding region made of silicon carbide on the lower surface, and silicon carbide, and the upper surface of the lower surface of the holding member A crystal growth apparatus comprising: a seed crystal holding body having a seed crystal disposed so as to be in contact with a bonding region. A holding member having carbon as a main component and having a bonding region made of silicon carbide on the lower surface, and a seed having a seed crystal made of silicon carbide and arranged so that the upper surface is in contact with the bonding region on the lower surface of the holding member Preparing a crystal carrier;
Growing a silicon carbide crystal from the melt on the lower surface of the seed crystal by bringing the lower surface of the seed crystal into contact with a silicon carbide melt in a crucible and pulling the holding member upward; A method for growing crystals.

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