JP7061911B2 - Single crystal manufacturing method and single crystal manufacturing equipment - Google Patents

Description

The present disclosure relates to a method for producing a single crystal such as a sapphire single crystal and a single crystal production apparatus.

Conventionally, as a method for growing a single crystal, an edge-defined film fed growth method (edge defined film fed growth method, hereinafter abbreviated as EFG method) has been known. In this method, the raw material of the single crystal filled in the pit is heated and melted, and the slit in the die (mold) installed in the pit is raised to the upper surface of the die by the capillary phenomenon to raise the seed crystal (seed). The melt is slowly cooled while pulling up the seed crystal, and a rod-shaped, plate (ribbon) -shaped, or tubular single crystal is grown. The production of a single crystal by such an EFG method is disclosed in, for example, Patent Document 1.

According to the EFG method, a single crystal can be produced while maintaining the plane orientation of the seed crystal. Therefore, there is an advantage that a single crystal having a desired plane orientation, for example, a plate-shaped single crystal having a main surface having a desired plane orientation can be obtained without performing complicated processing for adjusting the plane orientation in a subsequent step. There is.
On the other hand, in particular, when a plurality of slits are provided in the die to grow a plurality of single crystals at the same time, it is necessary not to reduce the quality and yield of each single crystal.

Japanese Unexamined Patent Publication No. 2016-47792

An object of the present disclosure is to provide a method for producing a single crystal and an apparatus for producing a single crystal, which can improve the crystal quality and stabilize the yield when a plurality of single crystals are grown at the same time.

The method for producing a single crystal according to the present disclosure is to grow a single crystal by the EFG method.
The process of filling the crucible with the raw material of the single crystal and inducing and heating the raw material in the crucible with a high-frequency coil surrounding the outer circumference of the crucible to melt it.
Seed crystals are placed on multiple melt surfaces supplied and held on the upper surface of the die placed in the crucible, and multiple single crystals are grown while pulling the seed crystals vertically from the multiple melt surfaces. Including the process of
It is characterized in that the relative positions of the dies arranged in the crucible and the high-frequency coils are adjusted so that the temperature distributions on the surfaces of the plurality of melts are uniform.

The single crystal manufacturing apparatus of the present disclosure is
A crucible filled with single crystal raw materials,
A heating means for melting the raw material in the crucible,
A die arranged in a crucible, having a plurality of slits for holding the molten liquid, and having a molten liquid surface formed on the upper surface of each slit.
A seed crystal is attached to the lower end, and it is equipped with a pulling means for growing a single crystal while pulling the seed crystal from a plurality of molten liquid surfaces corresponding to a plurality of slits.
The heating means determines the relative position of the high-frequency coil for induction heating surrounding the outer periphery of the pit, the induction heating control unit connected to the high-frequency coil, and the die that holds the high-frequency coil and is arranged in the pit. It is provided with a position adjusting means for adjusting.

According to the present disclosure, the relative positions of the die and the high-frequency coil are adjusted to make the temperature distribution of the plurality of melt surfaces uniform, so that the crystal quality can be improved and the yield can be stabilized. Crystals can be stably grown at the same time.

It is a schematic diagram for demonstrating the EFG method which concerns on this disclosure. It is a schematic sectional drawing which shows one Embodiment of the single crystal body manufacturing apparatus of this disclosure. It is a schematic perspective view which shows the method of producing a plurality of single crystals in an embodiment of this disclosure. It is a schematic diagram which shows the method of pulling up a single crystal body in this disclosure. It is a schematic diagram which shows the pull-up state of a single crystal body. (a) and (b) are schematic views showing the method of adjusting the horizontal relative position of a die and a high frequency coil in the present disclosure. It is a schematic diagram which shows an example of the die which concerns on this disclosure. It is a schematic diagram which shows the method of adjusting the relative position in the vertical direction of a die and a high frequency coil in this disclosure. It is a flowchart which shows one Embodiment of the manufacturing method of the crystal | body which concerns on this disclosure.

The single crystal (5, 105) according to the present disclosure is produced by the EFG method. In the EFG method, as conceptually shown in FIG. 1, a die (die) 102 having a slit (gap) 101 is installed in the crucible 100. The raw material of the single crystal filled in the crucible 100 is heated and melted by the high frequency coil 103 arranged on the outer periphery of the crucible 100. The obtained molten liquid 104 rises in the slit 101 to the upper surface of the die 102 by a capillary phenomenon. The single crystal 105 is grown by bringing the seed crystal into contact with the liquid surface of the molten liquid 104 and pulling it upward. In FIG. 1, reference numeral 106 indicates a solid-liquid interface between the melt 104 and the single crystal 105.
Although FIG. 1 shows a plate (ribbon) -shaped single crystal 105, a rod-shaped or tubular single crystal 105 can be obtained depending on the shape of the upper end surface of the die 102.

FIG. 2 shows a single crystal manufacturing apparatus according to an embodiment of the present disclosure, in which a plurality of single crystals 5 are grown at the same time. As shown in FIG. 2, the crucible 1 to which the raw material of the single crystal 5 is supplied is installed at the lower part in the growth chamber 10 and is held by the gantry 11. The growth chamber 10 is a container having an annular cross section, and is made of a refractory material such as Mo, W, W—Mo alloy, carbon, zirconia (ZrO ₂ ), or alumina. Further, the crucible 1 is made of molybdenum (Mo), tungsten (W), a tungsten molybdenum alloy (W—Mo), iridium (Ir) or the like.

The growing chamber 10 has a closed structure and is provided with a gas supply port and a gas discharge port (not shown). In order to prevent oxidation, an inert gas such as argon is supplied from the gas supply port into the growth chamber 10, and the single crystal is grown under the atmosphere of the inert gas.

A high-frequency coil 3 for heating is spirally wound around the outer periphery of the growing chamber 10 so as to surround the crucible 1. The high frequency coil 3 is an induction coil to which a high frequency voltage is applied and a high frequency current flows. That is, when a high-frequency current flows through the high-frequency coil 3, a magnetic field is formed around the crucible 1, and this magnetic field generates an eddy current on the surface of the crucible 1 to generate heat. As a result, the raw material of the single crystal filled in the crucible 1 is heated and melted by the high frequency coil 3.

Both ends of the high frequency coil 3 are electrically connected to the control unit 15 via the high frequency coil fixing unit 14, and a high frequency current is energized from the control unit 15. The high-frequency coil fixing portion 14 is formed in a plate shape, for example, and is attached to the XYZ stage 16. The XYZ stage 16 is a drive device whose position can be adjusted in three dimensions, and can be used by either an electric type or a manual type. FIG. 1 shows a manual XYZ stage 16 with knobs 16a, 16b, 16c for horizontal and vertical movement. As the XYZ stage 16, for example, an XYZ stage commercially available from Chuo Seiki Co., Ltd., Sigma Kouki Co., Ltd., Suruga Seiki Co., Ltd., etc. can be used.

A die 2 is installed and housed in the crucible 1. As shown in FIG. 3, a plurality of slits 12 are arranged side by side in the die 2 in one direction. The molten liquid obtained by heating and melting the raw material of the single crystal filled in the crucible 1 rises to the upper surface of the slit 12 due to the capillary phenomenon. As a raw material, for example, in the case of producing a sapphire single crystal, alumina (Al ₂ O ₃ ) is used.

Returning to FIG. 2, a seed holder 7 holding the seed crystal (seed) 6 at the lower end is installed above the die 2. The seed holder 7 is composed of a shaft body and can be raised and lowered in the vertical direction by a control means (not shown). The shape of the seed crystal 6 is not particularly limited, but has, for example, a plate-like shape, a rod-like shape, or the like (FIG. 3).

As shown in FIG. 3, the slit 12 of the die 2 is formed by two opposing plate members 13 and 13 constituting the die 2. The upper end surfaces of the two plate members 13 and 13 are formed in a slope shape so as to extend from the slit 12. The tip 6a of the seed crystal 6 comes into contact with the liquid surface of the molten liquid that has risen to the upper surface through the slit 12, and the seed holder 7 is raised in this state.
FIG. 4A shows a state in which the tip 6a of the seed crystal 6 is in contact with the liquid surface of the molten liquid 4. From this state, as shown in FIG. 4B, the melt 4 is pulled up while raising the seed crystal 6 at a predetermined constant speed. In FIG. 17B, reference numeral 17 indicates a solid-liquid interface.
FIG. 5 shows how the melt 4 is pulled up. The melt 4 is cooled in the process of being pulled up from the die 2, and a plate (ribbon) -shaped single crystal 5 is grown. In this embodiment, a plurality of single crystals 5 are grown at the same time using a plurality of seed crystals 6.

6 (a) and 6 (b) show the positional relationship between the die 2 and the high frequency coil 3 in the horizontal direction. A die 2 in which a plurality of slits 12 are arranged in one direction is housed in the crucible 1.
FIG. 6A shows that the crucible 1 is located concentrically with the high frequency coil 3. However, if the temperature distribution of the liquid surface of the melt liquid that has risen from the plurality of slits 12 on the upper surface of the die 2 is non-uniform among the slits 12, the quality of the obtained single crystal 5 and the yield may be lowered. , It becomes impossible to grow a plurality of single crystals 5 having uniform quality at the same time.

For example, in FIG. 6A, when there is a low temperature portion L and a high temperature portion H on the upper surface of the die 2, as shown in FIG. 6B, the low temperature portion L is brought closer to the high frequency coil 3. Adjust the positions of the die 2 and the high frequency coil 3. Specifically, by turning the knobs 16a and 16b of the XYZ stage 16 shown in FIG. 2, as shown in FIG. 6 (b), in the horizontal direction (the xy direction shown in FIG. 6 (b)) in the arrow A direction. The high frequency coil 3 is moved. As a result, the high frequency coil 3 approaches the low temperature portion L and the temperature rises, and conversely, the temperature of the high temperature portion H decreases as the high frequency coil 3 moves away, so that the temperature difference between the two portions is reduced. This makes it possible to make the temperature distribution on the surface of the molten liquid on the upper surface of the die 2 uniform.

Whether or not the temperature distribution of the liquid surface of each of the molten liquids rising in the plurality of slits 12 is uniform is determined by observing the crystal shape of each of the single crystal bodies 5 during the growth of the single crystal body 5. That is, when the crystal shapes of the plurality of single crystals 5 are not uniform, it indicates that the temperature distribution on each molten liquid surface is not uniform. Examples of the crystal shape showing the uniformity of the temperature distribution include the thickness of the single crystal 5 to be pulled up, the solid-liquid interface shape, and the like.

The breeding room 10 is provided with an observation window (not shown). Normally, two observation windows are provided so as to face each other in the y direction shown in FIG. 6 (b). From these windows, the crystal shape of the growing single crystal 6, that is, the solid-liquid interface 17 shown in FIG. 4B, the thickness of the single crystal 6, and the like can be visually observed or observed with a CCD camera.

As a result of observation, a portion where the solid-liquid interface 17 is low (lowered to near the slit 12) or the single crystal body 6 is thick indicates that the temperature of the die 2 in that portion is low. The opposite case, that is, the portion where the solid-liquid interface 17 is relatively high or the thickness of the single crystal body 6 is relatively thin indicates that the temperature of the die 2 in that portion is high.
Therefore, in the y direction shown in FIG. 6 (b), the crystal shapes in the y direction are compared from the observation results of the two observation windows on both sides, and the lower temperature (the lower temperature portion L) is selected. Bring the high frequency coil 3 closer.
On the other hand, in the x direction, the crystal shapes at the left and right ends of the die 2 are observed from one observation window, the crystal shapes in the x direction are compared, and the high frequency coil 3 is moved in the same manner as in the y direction.

Further, the temperature may become non-uniform at the center and ends of the die 2 instead of at both ends of the die 2, and a temperature gradient may be formed on the surface of the molten liquid. In such a case, the high frequency coil 3 is moved in the vertical direction (z direction) with respect to the die 2 to make the temperature distribution on the molten liquid surface uniform.
That is, the die 2 has a plurality of slits 12 arranged in one direction, but in the die 2 in the present embodiment, as shown in FIG. 7, the height of the slit 12 in the central portion C is the slit 12 at both ends E. The entire upper surface is curved in a concave shape, which is lower than the height of. That is, in the molten liquid surface formed on the upper surface of each slit 12, the molten liquid surface of the central portion C in the arrangement direction of the slits 12 is located at a lower position than the molten liquid surface of both ends E, and the plurality of molten liquid surfaces are present. They are arranged in a concave shape. The reason why the slits 12 are arranged so as to be curved in a concave shape in this way is to make the temperature gradient of the die 2 as uniform as possible.

Further, although not shown, it is preferable that not only the arrangement direction of the slits 12 but also the longitudinal direction of the slits 12 orthogonal to the arrangement direction is similarly curved in a concave shape. As a result, the upper surface of the die 2 is formed in a concave spherical shape as a whole. As a result, the temperature gradient of the die 2 can be made more uniform.

When the die 2 whose upper surface is curved in a concave spherical shape is used, as shown in FIG. 8, the plurality of seed crystals 6 attached to the lower ends of the seed holder 7 also have a shape in which the lower surface is curved in a convex spherical shape as a whole. As shown above, the central portion is long and both ends are short. In this state, a plurality of single crystals 5 are simultaneously grown by contacting the plurality of melts on the upper surface of the die 2 and pulling up the seed holder 7 at a predetermined speed.

In the method for growing a single crystal 5 shown in FIG. 8, when the temperature of the molten liquid surface is non-uniform between the central portion C and the end portion E of the die 2, the high frequency coil 3 is installed in the direction perpendicular to the molten liquid surface. Adjust the temperature by raising and lowering. That is, when the temperature of the central portion C of the die 2 is higher than the temperature of both ends E, the high frequency coil 3 is raised with respect to the die 2, the high frequency coil 3 is arranged near both ends E, and both ends are arranged. The temperature of the molten liquid surface in the portion E is raised.
On the contrary, when the temperature of the central portion C of the die 2 is lower than the temperature of both ends E, the high frequency coil 3 is lowered with respect to the die 2 to keep the high frequency coil 3 away from both ends E, and both ends. The temperature of the molten liquid surface in the portion E is lowered, and the temperature of the central portion C is relatively raised.

Whether or not the temperature of the molten liquid surface is uniform between the central portion C and the end portion E of the die 2 can be determined from the thickness of the ribbon-shaped single crystal 5 after growth. That is, the difference in the thickness of the single crystal 5 is confirmed between the central portion C and the end portion E of the die 2, and whether or not the temperature of the molten liquid surface is uniform is confirmed from the thickness distribution thereof, and then the single crystal is confirmed. The height of the high frequency coil 3 when raising the body 5 is determined.

When it is determined that the temperature of the molten liquid surface is not uniform between the central portion and the left and right end portions of the die 2 observed from the observation window described above, instead of the central portion C and the end portion E of the die 2. There is also. Even in such a case, the temperature can be made uniform by moving the high frequency coil 3 up and down with respect to the die 2.

To raise and lower the high frequency coil 3, the knob 16c of the XYZ stage 16 shown in FIG. 2 is turned to raise and lower the high frequency coil fixing plate 14.

Next, the method for producing the single crystal 5 in the present disclosure will be described with reference to FIG. FIG. 9 shows a manufacturing process of the single crystal body 5. First, in the first step (S201), the raw material of the single crystal is filled in the crucible 1. In the case of sapphire, high-purity alumina is used as a raw material. Then, the inside of the growth chamber 10 is replaced with argon gas. In addition, another inert gas may be used instead of the argon gas.

Next, a high frequency is applied to the high frequency coil 3 to heat and melt the raw material in the crucible 1 (S102). That is, the raw material is heated at a temperature equal to or higher than the melting point of alumina (about 2050 ° C.). The obtained melt 4 rises through a plurality of slits 12 formed in the die 2 in the crucible 1 by a capillary phenomenon, reaches the upper surface of the die 2, and is held as a melt.

The positions of the plurality of seed crystals 6 were adjusted so as to be parallel to the longitudinal direction of each slit 12 of the die 2 so that the plate-shaped single crystal 5 having a desired plane orientation (for example, c-plane) was formed. After that, the seed holder 7 is lowered to bring the seed crystal 6 into contact with the liquid surface of the raw material melt 4 held on the die 2 (S203).
The position adjustment is performed by rotating the seed holder 7 or rotating the crucible 1. The rotation may be performed manually or by driving the motor by a control means. Further, the contact may be made by bringing the tip of the seed crystal 6 into contact with at least the liquid surface of the molten liquid 4 held on the upper surface of the die 2.

Then, the seed holder 7 is raised at a predetermined speed to pull up the single crystal 5 (S204). At this time, the melt 4 spreads from the position in contact with the single crystal 5 over the entire length of the slit 12 on the upper surface of the die 2 in the longitudinal direction, and solidifies as the single crystal 5 is pulled up. Single crystal 5a (hereinafter, this is referred to as a first single crystal 5a) is simultaneously grown.

The crystal shape of the first single crystal 5a being grown is observed from an observation window, and the temperature distribution of each melt surface of the upper surface 2 of the die in the x direction and / or the y direction is confirmed (S205). As a result, when it is determined that the temperature distribution in the x-direction and / or the y-direction needs to be corrected, the high-frequency coil 3 is moved in the x-direction and / or the y-direction by the XYZ stage 16 (S206).

On the other hand, from the thickness distribution of the plurality of first single crystals 5a after growing, the temperature distribution of each molten liquid surface in the central portion and the peripheral portion of the die 2 is confirmed (S205). As a result, in the die 2 having a concave spherical upper surface as shown in FIGS. 7 and 8, when the temperature at the center of the die 2 is low, the high frequency coil 3 is lowered with respect to the die 2. As a result, the temperature at the upper end of the peripheral portion of the die 2 is lowered, and the central portion is not affected as much as the peripheral portion, so that the temperature distribution is made uniform.
When the temperature at the center of the die 2 is high, the high frequency coil 3 is raised with respect to the die 2. As a result, the temperature at the upper end of the peripheral portion of the die 2 rises and the temperature at the central portion relatively decreases, so that the temperature distribution becomes uniform.

After adjusting the positions of the die 2 and the high-frequency coil 3, the seed crystal 6 is pulled up from the melt 4 and cooled in the same manner as described above to cool the single crystal 5b (hereinafter, this is referred to as a second single crystal). (S207). As the seed crystal 6 used for growing the second single crystal 5b, the same seed crystal 6 used for growing the first single crystal 5a is used.
Then, the temperature distribution of the molten liquid surface is confirmed from each crystal shape of the obtained second single crystal 5b (S208).

Then, it is also determined whether or not the temperature distribution of the second single crystal 5b is uniform (S209). If the temperature distribution is not uniform or not (NO), the positional relationship between the die 2 and the high frequency coil 3 is adjusted again, a single crystal is grown, and it is confirmed whether the temperature distribution is uniform.
On the other hand, if the temperature distribution is uniform (YES), the production of the single crystal is continued using the same seed crystal 6. Even in that case, there may be a temperature difference on the upper surface of the die 2, so it is desirable to periodically check the temperature distribution in the same manner as described above.

In this way, when the temperature distribution on the upper surface of the die 2 is non-uniform, the position of the high frequency coil 3 is moved up, down, left and right to adjust the positions of the die 2 and the high frequency coil 3, so that the upper surface of the die 2 is adjusted. The temperature distribution of can be made uniform. This makes it possible to improve the quality of the single crystal 5 (for example, suppress bending, shrinkage of width, insufficient thickness, etc.) and stabilize the yield, particularly when a plurality of single crystals 5 are grown at the same time.

The method and apparatus for producing a single crystal of the present disclosure are not limited to the sapphire single crystal, and for example, silicon (Si), gallium oxide (Ga ₂ O ₃ ), rutile (TIO ₂ ) and the like. The same applies to the production of crystals.

Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various improvements and changes can be made within the scope of the claims. For example, in the above embodiment, the position of the high frequency coil 3 is moved with respect to the die 2 to adjust the positions of both, but conversely, the crucible 1 accommodating the die 2 is moved with respect to the high frequency coil 3. You may let me. In this case, the XYZ stage 16 may be attached to the gantry 11 that supports the crucible 1. Others are the same as those in the above embodiment.
Further, the position adjustment between the die 2 and the high frequency coil 3 may be performed only in the horizontal direction or only in the vertical direction, if necessary. In the case of only the horizontal direction, a simpler XY stage than the XYZ stage 16 can be used.
Further, instead of the XYZ stage 16 and the XY stage, other position adjusting means or devices may be used.

In the present disclosure, uniform temperature distribution means that, as described above, the crystal shapes (solid-liquid interface, thickness, etc.) of the plurality of single crystals 5 grown at the same time are substantially irrespective of the position of the die 2. Although it means that it is uniform, the temperature distribution may be confirmed by measuring the temperature of the liquid surface of each melt 4. For temperature measurement, for example, a thermography, a pyrometer, or the like can be used.

1,100 Crucible 2,102 Die 3,103 High frequency coil 4,104 Melt 5,105 Single crystal 5a First single crystal 5b Second single crystal 6 seed crystal 7 Seed holder 10 Growth chamber 11 Stand 12 , 101 Slit 13 Plate 14 High frequency coil fixing part 15 Control part 16 XYZ stage 16a, 16b, 16c Knob 17, 106 Solid-liquid interface

Claims (12)

It is a method for producing a single crystal that grows a single crystal by the edge-defined film fed growth method.
A step of filling the crucible with the raw material of the single crystal and inducing heating the raw material in the crucible with a high-frequency coil surrounding the outer periphery of the crucible to melt the crucible.
Seed crystals are placed on the upper surface of a die arranged in the crucible and having a plurality of slits arranged side by side in one direction with respect to a plurality of molten liquid surfaces supplied and held by rising in the slits. Including a step of growing a plurality of the single crystals while pulling the seed crystal vertically from the plurality of the melt planes.
The crystal shape of the plurality of single crystals is observed from a direction parallel to the direction of the slit, and when the crystal shape of each single crystal is not uniform, it is determined that the temperature distribution of the plurality of molten liquid surfaces is not uniform. ,
By moving the die and the high frequency coil relative to each other in the horizontal direction parallel to the molten liquid surface so that the high frequency coil approaches the portion where the temperature of the molten liquid surface is low, the plurality of the molten liquid surfaces are present. A method for producing a single crystal body, which comprises adjusting the temperature distribution so as to be uniform. The method for producing a single crystal according to claim 1, wherein the crystal shape of the single crystal is the height of the solid-liquid interface or the thickness of the single crystal to be pulled up. The method for producing a single crystal according to claim 1 or 2, wherein the observation from a direction parallel to the direction of the slit is an observation from both sides of the slit. It is a method for producing a single crystal that grows a single crystal by the edge-defined film fed growth method.
A step of filling the crucible with the raw material of the single crystal and inducing heating the raw material in the crucible with a high-frequency coil surrounding the outer periphery of the crucible to melt the crucible.
Seed crystals are placed on the upper surface of a die arranged in the crucible and having a plurality of slits arranged side by side in one direction with respect to a plurality of molten liquid surfaces supplied and held by rising in the slits. Including a step of growing a plurality of the single crystals while pulling the seed crystal vertically from the plurality of the melt planes.
In the die, the height of the slit at the center is lower than the height of the slits at both ends, and the melt surface at the center in the arrangement direction of the plurality of melt surfaces is higher than the melt surface at both ends. It is in a low position, and the plurality of melt surfaces are arranged in a concave shape.
During or after growing the single crystal from each melt surface, it is confirmed from the thickness distribution of the single crystal whether or not the temperature distribution of each melt surface at the center and both ends is uniform. death,
When the temperature of each melt surface in the central portion is higher than the temperature of the melt surfaces at both ends, the high frequency coil is attached to the die in the direction perpendicular to the melt surface at both ends. When the temperature of each molten liquid surface in the central portion is lower than the temperature of the molten liquid surfaces at both ends, the temperature is perpendicular to the die . A single crystal body characterized in that the temperature distribution of each melt surface at the central portion and the both ends is adjusted to be uniform by moving the high frequency coil relative to each other so as to move away from both ends. Manufacturing method. With respect to the plurality of molten liquid surfaces arranged in the crucible and supplied / held in the slits in one direction on the upper surface of the die in which the plurality of slits are arranged side by side in one direction. A step of arranging the seed crystal and growing the plurality of first single crystals while pulling the seed crystal vertically from the plurality of melt planes.
Observing each crystal shape of the plurality of first single crystals from a direction parallel to the direction of the slit, the temperature distribution of the plurality of molten liquid surfaces in the horizontal direction from the crystal shape of each single crystal. And the process of confirming
When it is determined that the temperature distribution of the plurality of molten liquid surfaces is not uniform, the die is placed in the horizontal direction parallel to the molten liquid surface so that the high frequency coil approaches the portion where the temperature of the molten liquid surface is low. The step of relatively moving the high frequency coil and
After adjusting the position, the seed crystal is arranged on the plurality of melt planes, and the seed crystal is pulled up vertically from the plurality of melt planes to grow a plurality of second single crystals. The method for producing a single crystal according to any one of claims 1 to 3. With respect to the plurality of molten liquid surfaces arranged in the crucible and supplied / held in the slits in one direction on the upper surface of the die in which the plurality of slits are arranged side by side in one direction. A step of arranging the seed crystal and growing the plurality of first single crystals while pulling the seed crystal vertically from the plurality of melt planes.
From the thickness distribution of the plurality of first single crystals, a step of confirming whether or not the temperature distribution of each molten liquid surface at the central portion and both ends in the arrangement direction of the plurality of molten liquid surfaces is uniform. When,
When the temperature of each melt surface in the central portion is higher than the temperature of the melt surfaces at both ends, the high frequency coil is attached to the die in the direction perpendicular to the melt surface at both ends. When the temperature of each molten liquid surface in the central portion is lower than the temperature of the molten liquid surfaces at both ends, the temperature is perpendicular to the die . A step of adjusting the temperature distribution of each molten liquid surface at the center portion and both ends thereof by moving the high frequency coil relative to each other so as to be away from both ends thereof.
After adjusting the position, the seed crystal is arranged on the plurality of melt planes, and the seed crystal is pulled up vertically from the plurality of melt planes to grow a plurality of second single crystals. The method for producing a single crystal according to claim 4. The method for producing a single crystal according to any one of claims 1 to 6, wherein the position adjustment between the die and the high frequency coil is performed by operating the XY stage or the XYZ stage to which the holding portion of the high frequency coil is attached. A crucible filled with single crystal raw materials,
A heating means for melting the raw material in the crucible,
A die arranged in the crucible, having a plurality of slits for holding the molten liquid, and having a molten liquid surface formed on the upper surface of each slit.
A seed crystal is attached to the lower end, and a pulling means for growing a single crystal while pulling the seed crystal from a plurality of molten liquid surfaces corresponding to the plurality of slits is provided.
The heating means includes an induction heating high-frequency coil that surrounds the outer periphery of the crucible, an induction heating control unit connected to the high-frequency coil, and the high-frequency coil for the die that holds the high-frequency coil and is arranged in the crucible. The single crystal manufacturing apparatus used in the method for manufacturing a single crystal according to any one of claims 1 to 7, further comprising a position adjusting means for adjusting the relative position of the above. The single crystal manufacturing apparatus according to claim 8, wherein the die has a height of the slit at the center lower than the height of the slit at both ends and the entire upper surface is curved in a concave shape. The single crystal manufacturing apparatus according to claim 8 or 9, wherein the position adjusting means moves the high frequency coil relative to at least in the horizontal direction parallel to the molten liquid surface. The single crystal manufacturing apparatus according to claim 8 or 9, wherein the position adjusting means moves the high frequency coil relative to the molten liquid surface in a vertical direction. The single crystal manufacturing apparatus according to any one of claims 8 to 11, wherein the position adjusting means includes a holding portion of a high-frequency coil and an XY stage or an XYZ stage to which the holding portion is attached.

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