JP2017105676A - Manufacturing method of single crystal, and manufacturing apparatus of single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a single crystal capable of controlling a growth shape of a single crystal by adjusting a temperature distribution in the radial direction of a seed crystal and the single crystal growing thereon during crystal growth.SOLUTION: In a manufacturing method of a single crystal, a seed crystal is disposed on a lid part of a crucible composed of a crucible body and the lid part, while a raw material is housed in the lower part of the crucible body. A raw material gas produced by subliming the raw material is supplied to develop the single crystal on the seed crystal. An insulation member divided into a plurality of pieces of the insulation member is disposed on the top face of the lid part. A part of a plurality of the pieces of the insulation member is moved in the vertical direction to adjust a temperature distribution in the radius direction in the crucible during crystal growth.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a single crystal manufacturing method and a single crystal manufacturing apparatus.

  Since silicon carbide has excellent performance such as high heat resistance, large breakdown voltage, wide energy band gap, and high thermal conductivity, it can be applied to high frequency semiconductor devices and high temperature resistant semiconductor elements. Currently, devices and elements using silicon have become the mainstream, but the limits to the improvement in performance are approaching from the physical properties limit, and expectations for silicon carbide with physical properties superior to silicon have been increasing in recent years. . Recently, attention has been focused on power electronics technology using silicon carbide as an energy-saving technology for reducing energy loss during various power conversions as a countermeasure to the global warming problem.

Conventionally, a sublimation recrystallization method has been known as a method for producing a silicon carbide single crystal for producing a silicon carbide single crystal (hereinafter referred to as “single crystal” as appropriate) from a seed crystal containing silicon carbide and a raw material for sublimation. Yes.
In this sublimation recrystallization method, a raw material for sublimation is heated to 2000 ° C. or higher to sublimate the raw material to generate a sublimation gas, and the sublimation gas is cooled to a temperature several tens to several hundreds of degrees lower than the raw material container. This is a method of growing a silicon carbide single crystal from this seed crystal by supplying it to the crystal.

  When a silicon carbide single crystal is grown using the sublimation recrystallization method, the growth rate of a seed crystal or a silicon carbide single crystal (hereinafter, abbreviated as “ingot” as appropriate) depends on the temperature of the sublimation raw material. It is known that the growth rate increases if the difference is large, and decreases if the difference is small (see, for example, Patent Document 1).

  In addition, in silicon carbide single crystals manufactured using the sublimation recrystallization method, it is known that the shape of the ingot during or at the end of growth affects the residual stress of the ingot in crystal growth ingots. For example, in the case of convex growth in which the central part of the ingot grows larger than other parts on the growth surface of the ingot, the residual stress in the ingot after growth becomes large, and ingot cracking is induced during processing, It is known that distortion increases (see, for example, Patent Document 2).

JP 2014-5159 A JP 2011-219294 A

  The growth shape of the silicon carbide ingot depends on the temperature distribution of the ingot during crystal growth. The growth shape of the silicon carbide ingot affects not only defects such as cracks and distortions, but also the quality of the substrate obtained from the ingot.

  For example, if the center of the ingot is convex growth with a larger growth amount than other parts, ingot cracking occurs due to the large residual stress inside the ingot, resulting in a decrease in the processing yield. As the ingot shape, a shape having a small difference in the growth amount of each part is preferred. Therefore, it is desirable to grow the crystal while controlling the shape.

  In crystal growth, shape adjustment tends to become difficult as the diameter increases and the amount of growth increases, so a precise shape adjustment method is required.

  The present invention has been made in view of the above circumstances, and the growth of a single crystal can be controlled by adjusting the temperature distribution in the radial direction of the seed crystal and the single crystal grown on the seed crystal during crystal growth. An object is to provide a manufacturing method and a single crystal manufacturing apparatus.

  The present invention provides the following means in order to solve the above problems.

(1) In the method for producing a single crystal according to one aspect of the present invention, a seed crystal is disposed in a lid part in a crucible composed of a crucible body and a lid part, and a raw material is accommodated in a lower part of the crucible body. In the method for producing a single crystal in which a raw material gas is supplied by sublimating and growing a single crystal on the seed crystal, a heat insulating member having a structure divided into a plurality of heat insulating member pieces is disposed on the upper surface of the lid portion. The crystal growth of the single crystal is performed by adjusting the temperature distribution in the crucible by moving a part of the plurality of heat insulating member pieces in the vertical direction during the crystal growth.

(2) In the method for producing a single crystal described in (1) above, some of the plurality of heat insulating member pieces may be detached during crystal growth.

(3) A single crystal manufacturing apparatus according to an aspect of the present invention includes a crucible composed of a crucible body and a lid, wherein a seed crystal is disposed in the lid, the raw material is accommodated in a lower portion of the crucible body, and the raw material Is a single crystal manufacturing apparatus for growing a single crystal on the seed crystal by supplying a raw material gas, comprising a heat insulating member disposed on an upper surface of the lid, wherein the heat insulating member includes a plurality of heat insulating members It has a structure divided into pieces, and at least a part of the plurality of heat insulating member pieces is movable in the vertical direction.

(4) In the single crystal manufacturing apparatus according to (3), the heat insulating member may be circular in a plan view, and the division may be axisymmetric with respect to the central axis of the circle.

(5) In the single crystal manufacturing apparatus according to any one of (3) and (4), one of the plurality of heat insulating member pieces includes the circular center, and is axially symmetric with respect to a central axis. It may have various shapes.

(6) In the single crystal manufacturing apparatus according to any one of (3) to (5), a part of the division may be made along a dividing line extending radially from a circular center. Good.

(7) In the single-crystal manufacturing apparatus according to any one of (3) to (6), the heat insulating member is made of any one of a carbon molding material, porous carbon, and glassy carbon whose main material is carbon. It may be.

  According to the method for producing a single crystal of the present invention, the growth shape of the single crystal can be controlled by adjusting the temperature distribution in the radial direction of the seed crystal and the single crystal grown on the seed crystal during the crystal growth.

  According to the single crystal manufacturing apparatus of the present invention, the growth shape of a single crystal can be controlled by adjusting the temperature distribution in the radial direction of the seed crystal and the single crystal grown on the seed crystal during crystal growth.

It is a cross-sectional schematic diagram which shows the single-crystal manufacturing apparatus which concerns on the 1st Embodiment of this invention. It is a plane schematic diagram which shows the heat insulation member which concerns on 1st Embodiment. It is a plane schematic diagram which shows the heat insulation member which concerns on 2nd Embodiment. It is a plane schematic diagram which shows the heat insulation member which concerns on 3rd Embodiment. It is a plane schematic diagram which shows the heat insulation member which concerns on 4th Embodiment. It is a plane schematic diagram which shows the heat insulation member which concerns on 5th Embodiment. It is a plane schematic diagram which shows the heat insulation member which concerns on 6th Embodiment. It is a cross-sectional schematic diagram for demonstrating an example of the shape adjustment method of a silicon carbide single crystal. It is a cross-sectional schematic diagram for demonstrating the other example of the shape adjustment method of a silicon carbide single crystal. It is a cross-sectional schematic diagram for demonstrating the other example of the shape adjustment method of a silicon carbide single crystal. It is a cross-sectional schematic diagram for demonstrating the other example of the shape adjustment method of a silicon carbide single crystal. It is a cross-sectional schematic diagram for demonstrating the other example of the shape adjustment method of a silicon carbide single crystal. It is a cross-sectional schematic diagram for demonstrating an example of the removal structure of a heat insulation member piece.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts may be given the same reference numerals in the drawings. In addition, in the drawings used in the following description, in order to make the characteristics easy to understand, the characteristic parts may be shown in an enlarged manner for convenience, and the dimensional ratios of the respective constituent elements are not always the same as the actual ones. In addition, the materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited thereto, and can be implemented with appropriate modifications within the scope of the effects of the present invention. . The configuration shown in one embodiment can also be applied to other embodiments.

  The present invention can be applied to a vapor phase growth method such as a sublimation recrystallization method and a CVD method. Hereinafter, a case where the sublimation recrystallization method is used will be described as an example. Moreover, although the case where a silicon carbide single crystal is manufactured will be described as an example, the method for manufacturing a single crystal and the single crystal manufacturing apparatus of the present invention are not limited to silicon carbide but can be applied to other materials.

[Single crystal manufacturing apparatus (first embodiment)]
With reference to FIGS. 1 and 2, the structure of a single crystal manufacturing apparatus to which the first embodiment of the present invention is applied will be described.
FIG. 1 is a schematic cross-sectional view showing a single crystal manufacturing apparatus according to a first embodiment of the present invention, which is a stage before a single crystal is grown on a seed crystal. In this figure, the heat insulating member installed on the upper surface of the crucible lid is not removed.

  A single crystal manufacturing apparatus 100 shown in FIG. 1 includes a crucible 1 composed of a crucible body 1a and a lid portion 1b, and a heat insulating member 2 disposed on the outer side (upper surface) of the lid portion 1a. A single crystal in which a seed crystal W is arranged on the lid 1b, a raw material 3 is accommodated in the lower part of the crucible 1, a raw material gas is supplied by sublimating the raw material 3, and a single crystal is grown on the seed crystal W It is a manufacturing apparatus, Comprising: The heat insulation member 2 has the structure divided | segmented into several heat insulation member piece 2A-2E (refer FIG. 2), At least one part of these heat insulation member pieces is movable to a perpendicular direction. .

  The single crystal manufacturing apparatus 100 further includes a growth vessel 4 that accommodates the crucible 1, heating means 5 that is arranged so as to surround the outer surface of the growth vessel 4, and a heat insulating member 2 that is arranged outside the lid portion 1b. The heat insulating member 22 is disposed so as to surround the outer surface of the crucible 1 other than being covered with the heat insulating member 2.

The growth container 4 has a housing part 4a for housing the crucible 1, the heat insulating member 2, and the like, and an introduction pipe 6a and an exhaust pipe 6b are connected to the housing part 4a. Arbitrary gas can be introduce | transduced into the accommodating part 4a and exhausted with the introduction pipe | tube 6a and the exhaust pipe 6b. Further, a vacuum pump (not shown) such as a turbo molecular pump is attached to the exhaust pipe 6b, and the container 4a can be brought into a high vacuum state by exhausting from the exhaust pipe 6b. For example, after exhausting the internal air from the exhaust pipe 6b to a reduced pressure state, high purity argon (Ar) gas is supplied from the introduction pipe 6a to the storage portion 4a, and the reduced pressure state is set again. Can be under reduced pressure in an argon (Ar) atmosphere.
The gas introduced into the growth vessel 4 is preferably an inert gas such as argon (Ar) or helium (He) or hydrogen (H ₂ ) gas. This is because these gases do not cause a special reaction with silicon carbide and also have an effect as a coolant.

  For example, a high-frequency heating coil can be used as the heating means 5. In this case, if a crucible 1 is made of, for example, graphite by generating a high frequency by passing an electric current, the crucible 1 can be heated by induction heating.

  The crucible 1 is composed of a divided crucible body 1a and a lid 1b, but the crucible body 1a and the lid 1b may be further divided. Further, the crucible body 1a and the lid 1b are a part divided into two parts, that is, the side where the raw material is stored and the side where the seed crystal is arranged, and the proportion of each of the whole crucible is As long as the function of each part can be exhibited, it is arbitrary.

  The crucible 1 has an internal space 10 inside. In the upper part in internal space 10, silicon carbide seed crystal W is attached to a pedestal (not shown). In addition, a lower portion in crucible body 1a (internal space 10) is filled with a sufficient amount of silicon carbide raw material powder 3 for crystal growth of a silicon carbide single crystal on silicon carbide seed crystal W.

  As a material for the crucible 1, it is preferable to use a material that is stable at high temperatures and generates little impurity gas. Specifically, for example, graphite (graphite), silicon carbide, and graphite (graphite) coated with silicon carbide or tantalum carbide (TaC) are preferably used.

  The pedestal is a portion to which the silicon carbide seed crystal W is attached, and is configured to protrude downward on the inner surface of the lid portion 1b. The illustrated pedestal is formed of a single material as a member integral with the lid 2b, but may be a separate member from the lid 1b.

The heat insulating member 2 and the heat insulating member 22 are installed so as to cover the entire crucible 2 with these heat insulating members. The heat insulating member 2 and the heat insulating member 22 are preferably disposed in close contact with the crucible.
The heat insulating member 2 and the heat insulating member 22 are for stably maintaining the crucible 1 at a high temperature, and the heat insulating member 2 and the heat insulating member 22 are stably maintained at a high temperature as necessary. Can be appropriately used a material whose thickness and thermal conductivity are adjusted, for example, a carbon fiber material, graphite or the like.
The heat insulating member 2 has a hole 2a so that a part of the upper surface of the lid 2b is exposed. The heat insulating member 22 has a hole 22a so that a part of the bottom surface of the crucible body 2a is exposed. These holes are for measuring and controlling the temperature of the crucible with the radiation thermometers 8a and 8b.

  It is preferable that the outer shape of the heat insulating member 2 is similar to the outer shape of the upper surface of the lid portion 2b. Moreover, it is preferable that the heat insulation member 2 completely covers the upper surface of the lid 2b.

The heat insulating member 2 has a structure divided into a plurality of heat insulating member pieces. That is, the heat insulating member 2 is composed of a plurality of heat insulating member pieces which are separate members, and the heat insulating member is assembled by concentrating the plurality of heat insulating member pieces so as to have a predetermined shape (for example, a circle) of the heat insulating member. It is what makes. It is preferable that the adjacent heat insulating member pieces are arranged closely without gaps, but may be configured so as to be separated from each other as long as the role as a heat insulating member can be exhibited. In addition, adjacent heat insulating member pieces can be joined to each other with an adhesive or the like before moving, as long as each heat insulating member piece can be moved in the vertical direction during crystal growth. The structure etc. may be sufficient. Moreover, the adjacent heat insulation member pieces may be configured to be fitted to each other, or may be connected by a connecting member. Here, the “vertical direction” means a direction perpendicular to the upper surface of the crucible lid (a direction parallel to the direction connecting the crucible lid and the crucible body). Note that “a configuration movable in the vertical direction” does not mean that movement other than the vertical direction is excluded, and since the heat insulating member is disposed on the upper surface of the lid portion, at least in the vertical direction to be separated from the upper surface of the lid portion. It is the structure including the process to move.
In the heat insulating member 2, at least a part of the plurality of heat insulating member pieces is movable in the vertical direction, and the temperature in the radial direction in the crucible is moved by moving a part of the plurality of heat insulating member pieces in the vertical direction during crystal growth. The distribution can be adjusted. The temperature distribution in the radial direction of the crystal growth surface is adjusted by adjusting the temperature distribution in the radial direction in the crucible.
Each of the plurality of heat insulating member pieces constituting the heat insulating member 2 can be detached from the heat insulating member 2, that is, removed. To remove the heat insulating member piece from the heat insulating member 2 means to separate the heat insulating member piece from other heat insulating member pieces constituting the heat insulating member 2. The temperature distribution in the radial direction in the crucible can be adjusted by detaching some of the plurality of heat insulating member pieces during crystal growth. Moreover, the heat insulating member piece desorbed during crystal growth can be returned to the original position of the heat insulating member. That is, the plurality of heat insulating member pieces can be attached and detached (removed, attached (returned to the original)). Moreover, it can also remove | desorb so that a heat insulation member piece may be completely removed from a heat insulation member, and it can also shift to the position where a part of heat insulation member piece remains in a heat insulation member (refer FIG. 12). That is, the distance from the upper surface of the lid portion of the heat insulating member piece can be adjusted. Thus, by adjusting the distance from the upper surface of the lid portion of the heat insulating member piece, the temperature distribution in the radial direction can be adjusted more precisely.

FIG. 2 is a schematic plan view of the heat insulating member according to the first embodiment.
The heat insulating member 2 shown in FIG. 2 has a circular shape in plan view as a whole, and includes a center O of the circular shape. From the circular heat insulating member piece 2A having an axially symmetric shape in plan view and the ring-shaped heat insulating member pieces 2B, 2C, 2D and 2E which are different in inner diameter and outer diameter and concentric with the central axis O. Become. In the ring-shaped heat insulating member pieces 2B, 2C, 2D and 2E, the heat insulating member pieces 2B having the smallest diameter and the heat insulating member pieces 2C, 2D and 2E having a large diameter are juxtaposed in order from the central axis to the outer periphery. The heat insulating member piece 2A has a hole 2a, which is not shown in FIG.
The temperature distribution in the radial direction in the crucible 1 can be adjusted by moving some of the heat insulating member pieces 2A to 2E in the vertical direction during crystal growth.

[Single crystal manufacturing apparatus (second embodiment)]
Since the single crystal manufacturing apparatus of the second embodiment is common to the first embodiment except for the heat insulating member, only the heat insulating member will be described.
In FIG. 3, the plane schematic diagram of the heat insulation member which concerns on 2nd Embodiment is shown.
The heat insulating member 32 shown in FIG. 3 has a circular shape in plan view as a whole, includes a center of the circle, and has a hexagonal heat insulating member piece 32A in plan view having an axisymmetric shape with respect to the central axis O, and the heat insulation thereof. Heat insulation member pieces 32B, 32C, 32D having a hexagonal inner periphery and a hexagonal outer periphery composed of sides parallel to each side of the member piece 32A, and juxtaposed in order from the central axis O, and a heat insulation member piece 32D The heat insulating member piece 32E has a hexagonal inner periphery parallel to each side of the outer periphery of the heat insulating member piece 32D and an outer periphery that is also the outer periphery of the heat insulating member 32.
The temperature distribution in the radial direction in the crucible 1 can be adjusted by moving some of the heat insulating member pieces 32A to 32E in the vertical direction during crystal growth.

[Single Crystal Manufacturing Apparatus (Third Embodiment)]
Since the single crystal manufacturing apparatus of the third embodiment is common to the first embodiment except for the heat insulating member, only the heat insulating member will be described.
In FIG. 4, the plane schematic diagram of the heat insulation member which concerns on 3rd Embodiment is shown.
The heat insulating member 42 shown in FIG. 4 further has the same area in each of the ring-shaped heat insulating member pieces 2B to 2E shown in FIG. 2 radially from the outer periphery of the heat insulating member piece 2A in the heat insulating member 2 shown in FIG. It has a structure divided by dividing lines L ₁ , L ₂ , L ₃ , L ₄ , L ₅ , L ₆ , L ₇ and L _{8 that} are arranged at equal intervals so as to be divided.
As the heat insulating member is divided more finely, the temperature distribution can be adjusted more precisely. Therefore, the heat insulating member 42 shown in FIG. 4 can adjust the temperature distribution more precisely than the heat insulating member 2 shown in FIG. Can do.

[Single crystal manufacturing apparatus (fourth embodiment)]
Since the single crystal manufacturing apparatus of the fourth embodiment is common to the first embodiment except for the heat insulating member, only the heat insulating member will be described.
In FIG. 5, the plane schematic diagram of the heat insulation member which concerns on 4th Embodiment is shown.
The heat insulating member 52 shown in FIG. 5 further extends radially so as to connect the inner and outer peripheral vertices of the heat insulating member pieces 32B to 32D from the outer peripheral vertex of the heat insulating member piece 32A in the heat insulating member 32 shown in FIG. Each of the ring-shaped heat insulating member pieces 32B to 32E shown in FIG. 3 is divided by dividing lines L ₁₁ , L ₂₁ , L ₃₁ , L ₄₁ , L ₅₁ , and L ₆₁ arranged at equal intervals so as to be divided into equal areas. It has the structure which was made.
As the heat insulating member is divided more finely, the temperature distribution can be adjusted more precisely. Therefore, the heat insulating member 52 shown in FIG. 5 has a more precise temperature distribution than the heat insulating member 2 shown in FIG. Can be adjusted.

[Single crystal manufacturing apparatus (fifth embodiment)]
Since the single crystal manufacturing apparatus of the fifth embodiment is the same as that of the first embodiment except for the heat insulating member, only the heat insulating member will be described.
FIG. 6 is a schematic plan view of a heat insulating member according to the fifth embodiment.
The heat insulating member 62 shown in FIG. 6 has a circular heat insulating member piece in a plan view that includes a circular center O and has an axisymmetric shape with respect to the central axis O, as compared with the heat insulating member 2 shown in FIG. In addition, the ring-shaped heat insulating member pieces arranged outside the circular heat insulating member pieces are common in that they are arranged concentrically with respect to the central axis O, but the heat insulating member 2 shown in FIG. While the widths of all the rings of the heat insulating member pieces 2B to 2E are equal, the heat insulating member 62 shown in FIG. 6 is different in that the widths of all the rings of the ring-shaped heat insulating member pieces 62B to 62E are different.
In the heat insulating member 62 shown in FIG. 6, the ring-shaped heat insulating member pieces 62 </ b> B to 62 </ b> E have different ring widths, but may have a ring-shaped heat insulating member piece having the same ring width.

[Single crystal manufacturing apparatus (sixth embodiment)]
Since the single crystal manufacturing apparatus of the sixth embodiment is common to the first embodiment except for the heat insulating member, only the heat insulating member will be described.
In FIG. 7, the plane schematic diagram of the heat insulation member which concerns on 6th Embodiment is shown.
Compared with the heat insulating member 32 shown in FIG. 3, the heat insulating member 72 shown in FIG. 7 includes a circular center O and a hexagonal heat insulating member piece in a plan view having an axisymmetric shape with respect to the central axis O. And a hexagonal inner circumference composed of sides parallel to each side of the hexagonal heat insulating member piece, except for the outermost heat insulating member piece, which is arranged outside the hexagonal heat insulating member piece. In addition, the heat insulating member 32 shown in FIG. 3 has the same width in all of the ring-shaped heat insulating member pieces 32B to 32D, whereas the heat insulating member 32 shown in FIG. 72 is different in that the widths of all the rings of the ring-shaped heat insulating member pieces 72B to 72D are different.
In the heat insulating member 72 shown in FIG. 7, all the ring-shaped heat insulating member pieces 72 </ b> B to 72 </ b> D have different ring widths, but may have a structure with ring-shaped heat insulating member pieces having the same ring width.

[Single crystal manufacturing method]
Next, a method for manufacturing a silicon carbide single crystal according to the present invention will be described with reference to the drawings.
The silicon carbide raw material 3 (for example, SiC powder) is filled in the crucible 1 of the single crystal manufacturing apparatus shown in FIG. 1, and the silicon carbide seed crystal W is fixed to the base of the lid portion 1b of the crucible. In the growth vessel 4 containing the crucible, after evacuation and gas introduction through the introduction pipe 6a and the exhaust pipe 6b and gas exchange, a high-purity Ar gas is introduced, and the inside of the growth container 4 (container 4a) ) Is set to an environment of 9.3 × 10 ⁴ Pa in an Ar atmosphere.
Next, the crucible 1 is heated to a temperature of 1900 ° C. or higher using the heating means 5. Thereby, the silicon carbide raw material powder 3 in the crucible 1 is heated to generate a raw material sublimation gas (raw material gas) from the silicon carbide raw material powder 3, and the generated raw material sublimation gas passes through the inner space (growth space) of the crucible. Thus, silicon carbide is recrystallized on the silicon carbide seed crystal W placed on the crucible lid 1b, which is at a lower temperature than the lower part of the crucible 1, and a silicon carbide single crystal grows. Since the growing crystal inherits the crystal structure of the seed crystal W, for example, if a 4H—SiC single crystal is used as the seed crystal, the 4H—SiC single crystal can be grown on the seed crystal.

According to the method for producing a single crystal of the present invention, a seed crystal is obtained by adjusting a temperature distribution in a crucible by moving a part of a plurality of heat insulating member pieces in a vertical direction while growing the single crystal. In addition, the temperature distribution of a single crystal grown thereon is adjusted to control the growth shape of the single crystal.
The method of moving the plurality of heat insulating member pieces is not particularly limited. For example, a rod or wire is attached to each heat insulating member piece, the rod or wire is extended outside the growth vessel, and the rod or wire is attached. The heat insulating member piece can be removed from the heat insulating member by pulling up. When a rigid rod or the like is used, the once removed heat insulating member piece can be returned to the heat insulating member depending on the state of crystal growth.
The material of the rod or wire is not particularly limited, but, for example, graphite can be used.
The method of attaching the rod or wire to each heat insulating member piece is not particularly limited. For example, the tip of the rod or wire may be formed into a fishhook shape and attached to the heat insulating member piece made of carbon fiber. it can.

  Hereinafter, a method of growing a single crystal by adjusting a temperature distribution in the radial direction in the crucible by moving a part of the plurality of heat insulating member pieces in the vertical direction will be described with reference to the drawings.

FIG. 8 is a schematic cross-sectional view for explaining an example of a method for adjusting the shape of a silicon carbide single crystal (ingot) using the structure shown in FIG. 2 as the heat insulating member. In the figure, only the crucible 1, the heat insulating member 2 composed of a plurality of heat insulating member pieces (2A to 2E), the silicon carbide raw material 3, and the silicon carbide single crystal S (seed crystal is not shown) are drawn.
The example shown in FIG. 8 is a case where the growing ingot shape has a large growth amount in the central portion, and the central portion swells in a convex shape on the raw material side is adjusted to a flat shape.

FIG. 8A shows a state where the heat insulating member piece is moved, and FIG. 8B shows a state after the heat insulating member piece is moved.
In order to adjust the state in which the growth amount of the end portion of the ingot is smaller than that of the central portion, the heat insulating member piece 2C located above the end portion of the ingot is moved in the vertical direction (upward), and the heat insulating member 2 Remove from.
Since the heat insulating member piece 2C is removed, the amount of heat released from the upper part of the end of the crucible ingot to the outside of the crucible increases, and as a result, the temperature of the end of the ingot decreases.
The temperature at the end of the ingot decreases, the recrystallization of the source gas at the end of the ingot is promoted, and the amount of crystal growth at the end of the ingot increases, resulting in a difference in growth from the center. It becomes possible to adjust to a small flat mold.

FIG. 9 is a schematic cross-sectional view for explaining another example of the method for adjusting the shape of a silicon carbide single crystal (ingot) using the structure shown in FIG. 2 as the heat insulating member. In the figure, only the crucible 1, the heat insulating member 2 composed of a plurality of heat insulating member pieces (2A to 2E), the silicon carbide raw material 3, and the silicon carbide single crystal S (seed crystal is not shown) are drawn.
The example shown in FIG. 9 is a case where the growing ingot shape has a small amount of growth in the central portion and the center portion is recessed into a concave shape to be adjusted to a flat shape.

FIG. 9A shows a state where the heat insulating member piece is moved, and FIG. 9B shows a state after the heat insulating member piece is moved.
In order to adjust the state in which the amount of growth in the central portion of the ingot is small compared to the end portion, the heat insulating member piece 2A located above the central portion of the ingot is moved in the vertical direction (upward), and the heat insulating member 2 Remove from.
By removing the heat insulating member piece 2A, the amount of heat released from the upper part of the central part of the crucible ingot to the outside of the crucible increases, and as a result, the temperature of the central part of the ingot decreases.
Lowering the temperature of the central part of the ingot promotes recrystallization of the raw material gas at the central part of the ingot, increasing the amount of crystal growth at the central part of the ingot, thereby increasing the difference in growth amount from the end part. It becomes possible to adjust to a small flat mold.

FIG. 10 is a schematic cross-sectional view for explaining another example of a method for adjusting the shape of a silicon carbide single crystal (ingot) using the heat insulating member having the structure shown in FIG. In the figure, only the crucible 1, the heat insulating member 2 composed of a plurality of heat insulating member pieces (2A to 2E), the silicon carbide raw material 3, and the silicon carbide single crystal S (seed crystal is not shown) are drawn.
The example shown in FIG. 10 is a case where the growing ingot shape is adjusted to a flat shape when the growth amount of the central portion and the end portion is small and the shape is M-shaped.

FIG. 10A shows a state where the heat insulating member piece is moved, and FIG. 10B shows a state after the heat insulating member piece is moved.
In order to adjust the state where the growth amount of the central portion and the end portion of the ingot is small compared to the end portion, the heat insulating member piece 2A and the heat insulating member piece 2C positioned above the central portion and the end portion of the ingot are vertically arranged. Move (upward) and remove from the heat insulating member 2.
By removing the heat insulating member pieces 2A and the heat insulating member pieces 2C, the amount of heat released from the crucible ingot central portion and the upper portion of the end portion to the outside of the crucible increases, and as a result, the central portion and the end portion of the ingot The temperature drops.
By lowering the temperature at the center and end of the ingot, recrystallization of the source gas at the center and end of the ingot is promoted, and the amount of crystal growth at the center and end of the ingot is increased. It becomes possible to adjust to a flat type with a small growth amount difference from other parts.

FIG. 11 is a schematic cross-sectional view for explaining another example of a method for adjusting the shape of a silicon carbide single crystal (ingot) using the structure shown in FIG. 2 as a heat insulating member. In the figure, only the crucible 1, the heat insulating member 2 composed of a plurality of heat insulating member pieces (2A to 2E), the silicon carbide raw material 3, and the silicon carbide single crystal S (seed crystal is not shown) are drawn.
The example shown in FIG. 11 is a case where the growing ingot shape is a W-shape with a small amount of growth at the position between the central portion and the end portion, and is adjusted to a flat shape.

FIG. 11A shows a state where the heat insulating member piece is moved, and FIG. 11B shows a state after the heat insulating member piece is moved.
In order to adjust the state where the amount of growth at the position between the center portion and the end portion of the ingot is small compared to the center portion and the end portion, the position is located above the position between the center portion and the end portion of the ingot. The heat insulating member piece 2B to be moved is moved in the vertical direction (upward) and removed from the heat insulating member 2.
By removing the heat insulating member piece 2B, the amount of heat released to the outside of the crucible from the upper portion of the position between the central portion and the end portion of the crucible ingot increases, and as a result, the central portion and the end portion of the ingot The temperature at the position between is lowered.
Reducing the temperature at the position between the central portion and the end portion of the ingot promotes recrystallization of the source gas at the position between the central portion and the end portion of the ingot, and the central portion and the end portion of the ingot. By increasing the crystal growth amount at a position between the two, it is possible to adjust to a flat type with a small difference in growth amount from other portions.

FIG. 12 is a schematic cross-sectional view for explaining another example of a method for adjusting the shape of a silicon carbide single crystal (ingot) using the structure shown in FIG. 2 as a heat insulating member. In the figure, only the crucible 1, the heat insulating member 2 composed of a plurality of heat insulating member pieces (2A to 2E), the silicon carbide raw material 3, and the silicon carbide single crystal S (seed crystal is not shown) are drawn.
In the example shown in FIG. 12, the growing ingot shape has the smallest amount of growth near the outer periphery between the central portion and the outer periphery, the center portion has the largest amount of growth, and the growth amount on the outer periphery is about the middle of them. This is a case of adjusting a flat shape to a flat shape.

FIG. 12A shows an arrangement configuration of the heat insulating member pieces in which the heat insulating member pieces 2B and 2C are moved once for shape adjustment after the start of ingot growth. In this case, the shape of the ingot is Since it was a distorted shape as shown in the figure (in the case of the arrangement configuration of the heat insulating member pieces shown in FIG. 12 (a), the shape of the ingot does not mean the distorted shape shown in FIG. 12 (a)). FIG. 12 (b) shows the position after the movement of the heat insulating member piece. FIG.
In the arrangement configuration of the heat insulating member pieces shown in FIG. 12 (a), the shape of the ingot has the smallest growth amount at the position near the outer periphery between the central portion and the outer periphery, the central portion has the largest growth amount, The growth amount is a strained shape that is about the middle of them. In order to adjust this distorted shape, only the heat insulating member piece 2C positioned above between the central portion and the outer periphery is moved in the vertical direction (upward). At this time, in order to adjust the deviation of the growth amount, the position after the heat insulating member piece 2B is detached is set closer to the crucible lid than the position of the heat insulating member piece 2C. With this position adjustment, the amount of heat released at the position of the heat insulating member piece 2B is smaller than the amount of heat released at the position of the heat insulating member piece 2C, so that the temperature drop at the position of the heat insulating member piece 2B at the tip of the ingot is reduced. Therefore, the difference in crystal growth amount is adjusted, and the shape of the ingot can be adjusted to a flat type. Further, in order to adjust the temperature, the heat insulating member piece 2C may not be completely detached and may be adjusted such that the heat insulating member piece 2C is stopped at a part of contact with the heat insulating member piece 2B. By such position adjustment, fine adjustment such as a distorted shape becomes possible.
As described with reference to FIG. 12, the movement of the heat insulating member piece for shape adjustment may be performed a plurality of times during the production of the ingot (single crystal).
Although the movement pattern (arrangement configuration) of the heat insulating member pieces for shape adjustment has been described with reference to FIGS. 8 to 12, these figures are exaggerated or simplified for easy understanding. The combination of the shape of the ingot and the movement pattern (arrangement configuration) of the heat insulating member pieces is merely an example.

FIG. 13 is a schematic cross-sectional view for explaining an example of a structure for removing a heat insulating member piece.
FIG. 13 shows a configuration in which the rod 11 is attached to a heat insulating member piece constituting the heat insulating member in the single crystal manufacturing apparatus shown in FIG. 1.
The number of rods 11 is not limited to one for each heat insulating member piece, and a plurality of rods 11 may be attached, and the number of rods 11 can be made suitable for removal.
In the example shown in FIG. 13, although it is the structure provided with the heat insulation member shown in FIG. 2, the two rods 11 are attached also to what was illustrated in each ring-shaped heat insulation member piece.

DESCRIPTION OF SYMBOLS 1 Crucible 1a Crucible body 1b Cover part 2, 32, 42, 52, 62, 72 Heat insulation member 3 Raw material (silicon carbide raw material, silicon carbide raw material powder)
4 Growth vessel 5 Heating means 11 Rod 100 Single crystal production apparatus W Seed crystal

Claims (7)

In a crucible composed of a crucible body and a lid portion, a seed crystal is arranged in the lid portion, a raw material is accommodated in the lower part of the crucible body, the raw material is sublimated and a raw material gas is supplied, and a single crystal is formed on the seed crystal. In the method for producing a single crystal for growing
A heat insulating member having a structure divided into a plurality of heat insulating member pieces is disposed on the upper surface of the lid portion, and a part of the plurality of heat insulating member pieces is moved in the vertical direction during crystal growth, so that the inside of the crucible A method for producing a single crystal, wherein the single crystal is grown by adjusting a temperature distribution.   The method for producing a single crystal according to claim 1, wherein a part of the plurality of heat insulating member pieces is desorbed during crystal growth. In a crucible composed of a crucible body and a lid portion, a seed crystal is arranged in the lid portion, a raw material is accommodated in the lower part of the crucible body, the raw material is sublimated and a raw material gas is supplied, and a single crystal is formed on the seed crystal. A single crystal manufacturing apparatus for growing
A heat insulating member disposed on the upper surface of the lid,
The single crystal manufacturing apparatus, wherein the heat insulating member has a structure divided into a plurality of heat insulating member pieces, and at least a part of the heat insulating member pieces is movable in a vertical direction.   The single crystal manufacturing apparatus according to claim 3, wherein the heat insulating member is circular in a plan view, and the division is axisymmetric with respect to a central axis of the circular shape.   5. The single crystal manufacturing method according to claim 3, wherein one of the plurality of heat insulating member pieces includes the circular center and has an axisymmetric shape with respect to a central axis. apparatus.   6. The single crystal manufacturing apparatus according to claim 3, wherein a part of the division is made along a division line extending radially from a circular center.   The single-crystal manufacturing apparatus according to any one of claims 3 to 6, wherein the heat insulating member is made of any one of a carbon molding material mainly composed of carbon, porous carbon, and glassy carbon.

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