Crystal growth apparatus

A crystal growth apparatus including: a heat source, a crucible including a container body in which a raw material can be received and a lid part on which a seed crystal can be mounted; a first heat insulating part which is disposed externally of the crucible and in which a first through-hole penetrating in a thickness direction is provided; a second heat insulating part which is disposed externally of the first heat insulating part and in which a second through-hole penetrating in a thickness direction is provided; a moving mechanism configured to move the first heat insulating part and the second heat insulating part relative to each other; and a radiation type temperature measuring unit configured to measure a temperature of the crucible via the first through-hole and the second through-hole.

CROSS-REFERENCE TO RELATED APPLICATION

Priority is claimed on Japanese Patent Application No. 2018-167067, filed Sep. 6, 2018, the content of which is incorporated herein by reference.

BACKGROUND

Field of the Invention

The present disclosure relates to a crystal growth apparatus, and particularly, to a crystal growth apparatus for growing a single crystal of a material such as silicon carbide (SiC).

Description of Related Art

Crystalline materials including a single crystal are widely used in high-tech devices of various industrial fields. For example, compared to silicon (Si), silicon carbide (SiC) has an additional digit in its breakdown field, has about 3 times the bandgap energy, and has about 3 times the thermal conductivity. For this reason, silicon carbide is useful for power devices, high-frequency devices, high-temperature operation devices, etc., and further improvement in quality is required in the future. Further, aluminum nitride (AlN) has about twice the bandgap energy of silicon carbide, and is being researched in view of power devices and so on.

A sublimation method is well known as one method of producing a single crystal of a material as described above. The sublimation method is a method of disposing a seed crystal composed of a single crystal on a mount disposed in a graphite crucible, heating the crucible to supply the seed crystal with a sublimation gas that is sublimated from a raw material powder in the crucible, and growing the seed crystal into a larger seed crystal. Since a temperature condition during the crystal growth in the sublimation method has a great influence on quality of the obtained single crystal, there is a need to accurately measure a temperature of the crucible when the single crystal undergoes crystal growth.

For example, as technology for obtaining a silicon carbide single crystal, an apparatus for producing a silicon carbide single crystal in which a through-hole is provided in an insulator disposed externally of a crucible and a temperature of an outer wall of the crucible is measured from the outside using a radiation thermometer is disclosed in Patent Document 1.

An apparatus for producing a silicon carbide single crystal that includes a holder that holds a material, a mount (a lid) that is installed to block an opening of the holder, an insulator that is disposed externally of the holder, and a temperature measuring hole that is provided at a position of the insulator which faces the mount is disclosed in Patent Document 2.

An apparatus for producing a silicon carbide single crystal that includes a first hole that is provided in a sidewall of a heating container, a second hole that is disposed externally of the heating container and is provided at a position corresponding to the first hole, and a pyrometer that measures a surface temperature of the SiC single crystal inside the heating container via the first hole and the second hole is disclosed in Patent Document 3.

Further, as technology for obtaining a nitride single crystal, an apparatus for producing a nitride single crystal that includes a growth container that has an opening in an upper portion thereof, a susceptor that blocks the opening, a chamber that holds the growth container and the susceptor in an internal space thereof and has a heat shield member on an entire inner wall thereof, and a thermometer that measures a temperature of an outer wall of the growth container via a window provided on the chamber is disclosed in Patent Document 4.

Further, as a constitution that blocks a hole for measuring a temperature, an apparatus for producing SiO2—TiO2-based glass that includes a radiation thermometer that measures a temperature of a growth plane of a glass ingot via observation openings (through-holes) provided in a furnace frame and a furnace wall, and a transparent glass window that is provided on the observation opening of the furnace frame is disclosed in Patent Document 5.

PATENT DOCUMENTS

[Patent Document 5] PCT International Publication No. WO2014/003129 However, the technologies of Patent Documents 1 to 4 have problems in that, due to a structure in which an internal space in which the crucible is installed always communicates with the outside of the apparatus via a through-hole, heat of the internal space flows out to the outside via the through-hole during heating of a raw material, and the temperature of an outer wall of the crucible is locally lowered around the through-hole, and thus the temperature of the crucible cannot be accurately measured.

Further, there is a risk that, due to a drop in heating efficiency and non-uniformity in temperature of the crucible, a shape of a single crystal ingot impairs symmetry, and a variation in quality occurs.

Further, when the single crystal undergoes crystal growth, a gas in the internal space may flow out to the outside, and a raw material contained in the gas may be recrystallized and precipitated on an inner wall of the through-hole. As a result, due to precipitates attached to the inner wall of the through-hole, the temperature of the crucible cannot be accurately measured in some cases.

In the technology of Patent Document 5, since the transparent glass window is simply disposed in the through-hole of the furnace wall, an outflow of heat occurs at the transparent glass window during heating of a raw material. Accordingly, as in Patent Documents 1 to 4, the temperature of an outer wall of the crucible is locally lowered around the through-hole, and thus it is difficult to accurately measure the temperature of the crucible. Furthermore, a method of curbing the outflow of heat from the through-hole of the furnace wall is not disclosed or suggested in any of Patent Documents 1 to 5.

The present disclosure has been made in view of the above problems, and is directed to providing a crystal growth apparatus capable of realizing an improvement in quality of a crystal by improving heating efficiency and reconciling uniformity of a temperature of a crucible with accurate measurement of the temperature of the crucible.

SUMMARY

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

A crystal growth apparatus is comprised of:

a heat source;

a crucible including a container body in which a raw material is to be received and a lid part on which a seed crystal is to be mounted;

a first heat insulating part which is disposed externally of the crucible and in which at least one first through-hole penetrating in a thickness direction is provided;

a second heat insulating part which is disposed externally of the first heat insulating part and in which at least one second through-hole penetrating in a thickness direction is provided;

a moving mechanism configured to move the first heat insulating part and the second heat insulating part relative to each other; and

a radiation type temperature measuring unit configured to measure a temperature of the crucible via the first through-hole and the second through-hole.

DETAILED DESCRIPTION

First Embodiment

FIG. 1Ais a sectional view schematically showing a constitution of a crystal growth apparatus according to a first embodiment of the present disclosure in a state during crystal growth.FIG. 1Bis a sectional view schematically showing a constitution of the crystal growth apparatus according to the first embodiment in a state when a temperature of a crucible is measured. The drawings used in the following description may show characterized portions in an enlarged scale for convenience in order to facilitate understanding of features, and dimensional ratios or the like of the components are not limited to those shown.

As shown inFIG. 1A, a crystal growth apparatus1is comprised of a heat source11, a crucible14that includes a container body12in which a raw material A1can be received and a lid part13on which a seed crystal B1can be mounted, a first heat insulating part16which is disposed externally of the crucible14and in which a first through-hole15(at least one through-hole) penetrating in a thickness direction is provided, a second heat insulating part18which is disposed externally of the first heat insulating part16and in which a second through-hole17(at least one through-hole) penetrating in a thickness direction is provided, a moving mechanism19that moves the first heat insulating part16and the second heat insulating part18relative to each other, and a radiation type temperature measuring unit20that measures a temperature of the crucible14via the first through-hole15and the second through-hole17.

The heat source11is, for example, a high-frequency coil, and heats the raw material A1using a direct heating method. An induced current is generated near a surface of the crucible14by a magnetic field generated when an alternating current flows to the high-frequency coil, Joule heat thereof causes the crucible14to generate heat, and the raw material A1is heated by conduction of the heat. The heat source11is not limited to this direct heating method and an indirect heating method may be adopted.

The container body12of the crucible14is made up of a lower portion and a trunk portion. For example, the lower portion and the trunk portion, which are different members, are formed by junction. However, without being limited thereto, the lower portion and the trunk portion may be integrally formed. The container body12is filled with a sufficient amount of the raw material A1to grow the seed crystal B1.

The lid part13is mounted on the container body12to block an upper end opening of the container body12. The seed crystal B1is fixed to a lower surface13aof the lid part13. The seed crystal B1and the lid part13may be fixed using a carbon adhesive, and may be physically brought into close contact with each other by providing a fixing member (not shown).

The crucible14preferably has a circular shape in a top view. However, in a case where the moving mechanism19is a lifting device (to be described below), the crucible14can have a different shape instead of the circular shape.

Materials that are stable at a high temperature and generate less of an impurity gas are preferably used as a material of the crucible14. To be specific, for example graphite, silicon carbide, and graphite coated with silicon carbide or tantalum carbide (TaC) are preferably used.

The first heat insulating part16is movably provided along with the crucible14, and is loaded, for example, on a loading table (to be described below) of the moving mechanism19along with the crucible14.

The first heat insulating part16includes a first sidewall16athat is disposed to surround an outer surface14aof the crucible14, and a first upper wall16bthat is disposed to cover an upper surface of the crucible14, namely an upper surface13bof the lid part13. The first sidewall16ais separate from the first upper wall16b,but the first sidewall16amay be integrated with the first upper wall16b.

The first heat insulating part16preferably has a circular shape, for example, in a top view. However, in the case where the moving mechanism19is the lifting device (to be described below), the first heat insulating part16can have a different shape instead of the circular shape. The thickness of the first heat insulating part16is, for example, 5 mm to 100 mm.

The first heat insulating part16is formed of, for example, a material such as carbon fiber, and can stably maintain the temperature of the crucible14in a high-temperature area. As long as the first heat insulating part16can stably maintain the temperature of the crucible14in the high-temperature area, the first heat insulating part16can be formed of a different material instead of the carbon fiber after the thickness and thermal conductivity thereof are adjusted.

The first through-hole15is, for example, a first transverse hole that is provided to pass through the first sidewall16a.The first through-hole15has a shape and dimensions through which radiant light emitted from the crucible14can pass. In a case where the raw material A1is a powder, the first through-hole15is preferably provided at a vertical position corresponding to a region of the crucible14in which the raw material A1is held. Thus, the temperature of the raw material A1when the seed crystal B1is grown can be accurately measured.

The second heat insulating part18is fixed to a furnace body in the present embodiment. In this case, the first heat insulating part16is provided to be movable along with the crucible14, the moving mechanism19moves the crucible14and the first heat insulating part16relative to the second heat insulating part18.

In the present embodiment, the second heat insulating part18includes a second sidewall18athat is disposed to surround an outer surface16cof the first sidewall16a,and a leg part18bthat supports the second sidewall18a.

Like the crucible14and the first heat insulating part16, the second heat insulating part18preferably has a circular shape in a top view. However, in the case where the moving mechanism19is the lifting device (to be described below), the second heat insulating part18can have a different shape instead of the circular shape. The thickness of the second heat insulating part18is, for example, 5 mm to 100 mm.

The second heat insulating part18is formed of, for example, a material such as carbon fiber, and can stably maintain the temperature of the crucible14in the high-temperature area. Like the first heat insulating part16, as long as the second heat insulating part18can stably maintain the temperature of the crucible14in the high-temperature area, the second heat insulating part18can be formed of a different material instead of the carbon fiber.

The second through-hole17is, for example, a second transverse hole that is provided to pass through the second sidewall18a.Like the first through-hole15, the second through-hole17has a shape and dimensions through which radiant light emitted from the crucible14can pass. Further, the second through-hole17is preferably provided at the same vertical position as the first through-hole15. Thus, the first through-hole15and the second through-hole17can reliably cause to communicate with each other by simply turning the crucible14and the first heat insulating part16.

The moving mechanism19moves both the crucible14and the first heat insulating part16relative to the second heat insulating part18. In the present embodiment, the moving mechanism19includes a turning device21that is configured to turn the crucible14and the first heat insulating part16around an axis that extends in a vertical direction. The turning device21includes a loading table21athat loads both the crucible14and the first heat insulating part16, a shaft part21bthat is mounted on a lower portion of the loading table21a,and a motor (not shown) that rotates the shaft part21b.All of the crucible14, the first heat insulating part16, and the second heat insulating part18have circular shapes in a top view, and can be disposed coaxially with one another or equivalent to this.

The radiation type temperature measuring unit20is made up of, for example, an optical detection part, a photoelectric conversion part, a temperature output part, and so on, and measures the temperature of the crucible14, particularly a temperature of the container body12, on the basis of the radiant light emitted from the crucible14. The radiation type temperature measuring unit20is typically a handheld or mounted radiation thermometer.

The raw material A1can be composed of, for example, a SiC-containing powder or an AlN-containing powder.

The seed crystal B1can be composed of any material selected from the group consisting of SiC, AN, GaN, GaAs, and Si. In a case where the raw material A1is composed of the SiC-containing powder or the AlN-containing powder, the seed crystal B1is composed of, for example, a SiC single crystal or an AN single crystal. To be specific, the raw material A1is composed of the SiC-containing powder, and the seed crystal B1is composed of the SiC single crystal. Alternatively, the raw material A1is composed of the AlN-containing powder, and the seed crystal B1is composed of the AN single crystal. However, without being limited thereto, the raw material A1may be composed of the SiC-containing powder, and the seed crystal B1may be composed of the AN single crystal. Alternatively, the seed crystal B1may not be a single crystal, but may be a crystal consisting primarily of a single crystal, or a polycrystal.

In the crystal growth apparatus1having the constitution as described above, in the state in which the second heat insulating part18is fixed to the furnace body, the turning device21turns both the crucible14and the first heat insulating part16, and moves the first through-hole15of the first heat insulating part16to a position that is shifted from the second through-hole17of the second heat insulating part18. For example, in a top view of the crystal growth apparatus1, when an axial direction of the second through-hole17is 0°, the first through-hole15is turned to a position at which an axial direction of the first through-hole15becomes 180° (FIG. 1A). Thus, the first through-hole15is blocked by the second heat insulating part18.

Next, the heat source11is supplied with power, and heats the raw material A1in the crucible14. A heating temperature of the raw material A1is, for example, 1900 to 2500° C. Due to this heating, the raw material A1sublimates, and a raw material gas is generated. The raw material gas is supplied onto the seed crystal B1, and the seed crystal B1undergoes crystal growth.

Further, when the temperature of the crucible14is measured, the turning device21turns both the crucible14and the first heat insulating part16, and moves the first through-hole15of the first heat insulating part16to a position that is lined up with the second through-hole17of the second heat insulating part18in a linear shape. For example, in the top view of the crystal growth apparatus1, when the axial direction of the second through-hole17is 0°, the first through-hole15is turned to a position at which the axial direction of the first through-hole15becomes 0° (FIG. 1B). Thus, the first through-hole15communicates with the second through-hole17.

The radiant light emitted from the crucible14is measured from the radiation type temperature measuring unit20via the first through-hole15and the second through-hole17. Since the first through-hole15and the second through-hole17are lined up with each other in a linear shape, the light emitted from the crucible14reaches the radiation type temperature measuring unit20, and a temperature of the sidewall of the crucible14is measured in a short time. When the temperature measurement is completed, the turning device21turns both the crucible14and the first heat insulating part16, and moves the first through-hole15of the first heat insulating part16to the position that is shifted from the second through-hole17of the second heat insulating part18. Thus, the first through-hole15is blocked by the second heat insulating part18, and an outflow of heat and an outflow of the raw material gas from the crucible14are curbed. Further, the above operation is repeated as needed, and thereby the temperature of the crucible14during crystal growth is measured a plurality of times.

As described above, according to the present embodiment, the first heat insulating part16is disposed externally of the crucible14, and the first through-hole15penetrating in a thickness direction is provided in the first heat insulating part16. Further, the second heat insulating part18is disposed externally of the first heat insulating part16, and the second through-hole17penetrating in a thickness direction is provided in the second heat insulating part18. The moving mechanism19moves the first heat insulating part16and the second heat insulating part18relative to each other, and the radiation type temperature measuring unit20measures the temperature of the crucible14via the first through-hole15and the second through-hole17. Accordingly, the positions of the first through-hole15and the second through-hole17are shifted during heating of the crucible14. Thereby, an outflow of heat from the first through-hole15is prevented, and a phenomenon in which the temperature of the outer wall of the crucible14around the first through-hole15is locally lowered can be prevented. Especially, in a case where the raw material A1is SiC, SiC needs to be sublimated at a high temperature, and thus the outflow of heat from the first through-hole15is prevented. Thereby, a quality of the SiC single crystal can be improved. Further, when the temperature of the crucible14is measured, the positions of the first through-hole15and the second through-hole17are aligned, and thereby the temperature of the crucible14, particularly the container body12, can be accurately measured in a short time. In addition, during crystal growth other than in the event of the temperature measurement, the first through-hole15is blocked by the second heat insulating part18.

Thus, the raw material gas hardly reaches the second through-hole17, and the raw material is hardly precipitated on an inner wall of the second through-hole17. A failure in the temperature measurement caused by presence of precipitates does not occur. Therefore, an improvement in quality of a crystal can be realized by improving heating efficiency and reconciling uniformity of the temperature of the crucible with accurate measurement of the temperature of the crucible.

Further, since all of the crucible14, the first heat insulating part16, and the second heat insulating part18have circular shapes in a sectional view in a horizontal direction, and are disposed coaxially with one another or equivalent to this, and since the turning device21turns the crucible14and the first heat insulating part16around the axis extending in the vertical direction, the first heat insulating part16and the second heat insulating part18can be moved relative to each other with ease.

Furthermore, since the first heat insulating part16includes the first sidewall16athat is disposed to surround the outer surface14aof the crucible14, since the first through-hole15is the first transverse hole that is provided to pass through the first sidewall16a,since the second heat insulating part18includes the second sidewall18athat is disposed to surround the outer surface16cof the first sidewall16a,and since the second through-hole17is the second transverse hole that is provided to pass through the second sidewall18a,the positions of the first transverse hole and the second transverse hole can be shifted in a transverse direction or be aligned by turning the crucible14and the first heat insulating part16, and the uniformity of the temperature of the crucible can be compatible with the accurate measurement of the temperature of the crucible.

Second Embodiment

FIG. 2Ais a sectional view schematically showing a constitution of a crystal growth apparatus2according to a second embodiment of the present disclosure in a state during crystal growth.FIG. 2Bis a sectional view schematically showing a constitution of the crystal growth apparatus2according to the second embodiment in a state when a temperature of a crucible is measured. The crystal growth apparatus2of the second embodiment is different from that of the first embodiment in that a moving mechanism19includes a lifting device instead of the turning device. The components that are the same as those of the first embodiment will be given the same reference numbers as in the first embodiment, and different portions will be described below.

As shown inFIG. 2A, the moving mechanism19includes a lifting device22that raises/lowers a crucible14and a first heat insulating part16. The lifting device22includes a loading table22athat loads both the crucible14and the first heat insulating part16, a shaft part22bthat is mounted on a lower portion of the loading table22a,and a cylinder body (not shown) that is installed to make the shaft part22bmovable in a vertical direction.

A second through-hole17is a second transverse hole that is provided to pass through a second sidewall18a.In the present embodiment, the second through-hole17is preferably provided at the same transverse (circumferential) position as a first through-hole15. Thus, the first through-hole15and the second through-hole17can reliably communicate with each other by simply raising/lowering the crucible14and the first heat insulating part16.

In the crystal growth apparatus2, during or before heating of the crucible14, the lifting device22moves both the crucible14and the first heat insulating part16downward (or upward), and moves the first through-hole15of the first heat insulating part16to a position shifted from the second through-hole17of the second heat insulating part18. Thus, the first through-hole15is blocked by a second heat insulating part18.

On the other hand, when the temperature of the crucible is measured, the lifting device22moves both the crucible14and the first heat insulating part16upward (or downward), and moves the first through-hole15of the first heat insulating part16to a position lined up with the second through-hole17of the second heat insulating part18(FIG. 2B). Thus, the first through-hole15communicates with the second through-hole17, and the temperature of the crucible14is measured in this state.

In this way, in the present embodiment, when the crucible14is heated, the first through-hole15is blocked by the second heat insulating part18, and an outflow of heat and an outflow of a raw material gas from the crucible14are curbed. Further, when the temperature of the crucible14is measured, the first through-hole15communicates with the second through-hole17, and the temperature of the crucible14, particularly the container body12, can be measured by a radiation type temperature measuring unit20.

Therefore, the same effects as in the first embodiment can be exhibited.

Third Embodiment

FIG. 3is a sectional view schematically showing a constitution of a crystal growth apparatus3according to a third embodiment of the present disclosure. The crystal growth apparatus3of the third embodiment is different from that of the first embodiment in that a first through-hole and a second through-hole are provided above a crucible14. The components that are the same as those of the first embodiment will be given the same reference numbers as in the first embodiment, and different portions will be described below.

As shown inFIG. 3, a first heat insulating part16includes a first upper wall16bthat is disposed to cover an upper surface13bof a lid part13, and a first through-hole31penetrating in a thickness direction is provided in the first upper wall16b.The first through-hole31is, for example, a first longitudinal hole that is provided to pass through the first upper wall16b.The first through-hole31is preferably provided at a position corresponding to a position at which a seed crystal B1is mounted, namely in the vicinity of the seed crystal B1. Thus, the temperature of the seed crystal B1when the seed crystal B1is grown can be accurately measured.

A second heat insulating part32includes a second sidewall32athat is disposed to surround the outer surface16cof the first sidewall16a,a leg part32bthat supports the second sidewall32a,and a second upper wall32cthat is disposed to cover an upper surface16dof the first upper wall16b.A second through-hole33penetrating in a thickness direction is provided in the second upper wall32c.

The second through-hole33is, for example, a second longitudinal hole that is provided to pass through the second upper wall32cin a vertical direction. The second through-hole33is preferably provided at the same position as the first through-hole31in a radial direction centered on a turning axis in a top view of the crystal growth apparatus3. Thus, the first through-hole31and the second through-hole33are caused to communicate with each other by simply turning the crucible14and the first heat insulating part16.

A radiation type temperature measuring unit34measures the temperature of the crucible14, particularly a temperature of the lid part13, on the basis of radiant light emitted from above the crucible14.

In the crystal growth apparatus3, during or before heating of the crucible14, both the crucible14and the first heat insulating part16are turned, and the first through-hole31of the first heat insulating part16is moved to a position shifted from the second through-hole33of the second heat insulating part32. In the crystal growth apparatus3ofFIG. 3, a gap between the first upper wall16band the second upper wall32cis provided. However, as long as the first through-hole31and the second through-hole33have a shifted position relationship, a distance of a transfer route of heat that is directed from the crucible14to the outside of the apparatus is increased, and an outflow of heat can be curbed. Further, the second upper wall32cmay be disposed such that there is no gap between the first upper wall16band the second upper wall32c.

When the temperature of the crucible is measured, both the crucible14and the first heat insulating part16are turned, and the first through-hole31of the first heat insulating part16is moved to a position that is lined up with the second through-hole33of the second heat insulating part32in a linear shape. Thus, the first through-hole31communicates with the second through-hole33, and the temperature of the crucible14is measured in this state.

According to the present embodiment, when the crucible14is heated, an outflow of heat and an outflow of a raw material gas from the crucible14are curbed by shifting positions of the first through-hole31and the second through-hole33. Further, when the temperature of the crucible14is measured, the positions of the first through-hole31and the second through-hole33are aligned, and thereby the temperature of the crucible14, particularly the lid part13, can be measured by the radiation type temperature measuring unit34. Therefore, a temperature of a seed crystal B1during crystal growth can be accurately measured, and the same effects as in the first embodiment can be exhibited.

Fourth Embodiment

FIG. 4is a sectional view schematically showing a constitution of a crystal growth apparatus4according to a fourth embodiment of the present disclosure. The crystal growth apparatus4of the fourth embodiment is different from that of the third embodiment in that two first through-holes are provided in a first heat insulating part and two second through-holes are provided in a second heat insulating part. The components that are the same as those of the third embodiment will be given the same reference numbers as in the third embodiment, and different portions will be described below.

As shown inFIG. 4, the two first through-holes31and41provided in the first heat insulating part16are, for example, a first longitudinal hole that is provided to pass through a first upper wall16b,and a first transverse hole that is provided to pass through a first sidewall16a.Further, the two second through-holes33and43provided in the second heat insulating part32are, for example, a second longitudinal hole that is provided to pass through a second upper wall32c,and a second transverse hole that is provided to pass through a second sidewall32a.

As described above, a radiation type temperature measuring unit34measures a temperature of a lid part13on the basis of radiant light emitted from above a crucible14. Further, a radiation type temperature measuring unit44measures a temperature of the container body12on the basis of radiant light emitted from a lateral surface of the crucible14. In the crystal growth apparatus4, when or before the crucible14is heated, a turning device21turns both the crucible14and the first heat insulating part16, and moves the first through-hole31of the first heat insulating part16to a position shifted from the second through-hole33of the second heat insulating part32. Further, the turning device21moves the first through-hole41of the first heat insulating part16to a position shifted from the second through-hole43of the second heat insulating part32.

Further, when a temperature of the crucible is measured, the turning device21turns both the crucible14and the first heat insulating part16, and moves the first through-hole31of the first heat insulating part16to a position that is lined up with the second through-hole33of the second heat insulating part32in a linear shape. Further, the turning device21moves the first through-hole41of the first heat insulating part16to a position that is lined up with the second through-hole43of the second heat insulating part32in a linear shape. Thus, the first through-hole31communicates with the second through-hole33, and the first through-hole41communicates with the second through-hole43. In this state, both the temperature of the lid part13and the temperature of the container body12are measured.

According to the present embodiment, the temperature of the crucible14, particularly the temperature of the lid part13and the temperature of the container body12, can be measured by the radiation type temperature measuring units34and44. Therefore, both a temperature of a seed crystal B1and a temperature of a raw material A1during crystal growth can be measured. Particularly, in a case where all of the crucible14, the first heat insulating part16, and the second heat insulating part32have circular shapes in a sectional view in a horizontal direction and are disposed coaxially with one another or equivalent to this, both the temperature of the seed crystal B1and the temperature of the raw material A1during crystal growth can be simultaneously measured by simply turning the crucible14and the first heat insulating part16around an axis extending in a vertical direction.

Fifth Embodiment

FIG. 5is a sectional view schematically showing a constitution of a crystal growth apparatus5according to a fifth embodiment of the present disclosure, andFIG. 6is a view showing a modification of the crystal growth apparatus5ofFIG. 5. In the crystal growth apparatus5ofFIG. 5and a crystal growth apparatus6ofFIG. 6, a constitution of a heat source is different from that of the first embodiment. The components that are the same as those of the first embodiment will be given the same reference numbers as in the first embodiment, and different portions will be described below.

As shown inFIG. 5, the heat source51of the crystal growth apparatus5includes a high-frequency coil52and a heater53. For example, a graphite heater can be used as the heater53. The heater53is provided between the crucible14and the first heat insulating part16, and is preferably disposed to surround an outer surface14aof a crucible14. The constitution of the heat source51is not limited to this, and may be another constitution in which a raw material A1can be heated by an indirect heating method.

Further, as shown inFIG. 6, only a heater53is provided on the crystal growth apparatus6as the heat source, and electrodes54capable of supplying power from the outside may be connected to the heater53. In this case, the heat source is not limited to the heater, and may have another constitution in which the raw material A1can be heated by a resistance heating method.

The same effects as in the first embodiment can also be exhibited by the present embodiment.

Sixth Embodiment

FIG. 7is a sectional view schematically showing a constitution of a crystal growth apparatus7according to a sixth embodiment of the present disclosure. The crystal growth apparatus7of the sixth embodiment is different from that of the first embodiment in that a raw material is a gas, and is subjected to crystal growth by a gas method. The components that are the same as those of the first embodiment will be given the same reference numbers as in the first embodiment, and different portions will be described below.

The crystal growth apparatus7includes a first gas introduction part64that is provided on a container body61of a crucible63, a first gas discharge part65that is provided on a lid part62of the crucible63, a second gas introduction part66that is provided to pass through the centers of a loading table21aand a shaft part21bof a turning device21and communicates with the first gas introduction part64, and a second gas discharge part67that is provided on a first upper wall16bof a first heat insulating part16and communicates with the first gas discharge part65. A moving mechanism19includes the turning device21in the present embodiment, but it may include a lifting device instead of the turning device.

The shape of the first gas introduction part64has no limitation, but may be, for example, a round hole. The second gas introduction part66has a shape corresponding to the shape of the first gas introduction part64, and preferably has the shape of a round hole provided at the same position as the first gas introduction part64in a top view of the crystal growth apparatus7.

The shape of the first gas discharge part65is, for example, an annular hole. The second gas discharge part67has a shape corresponding to the shape of the first gas discharge part65, and preferably has the shape of an annular hole provided at the same position as the first gas discharge part65in the top view of the crystal growth apparatus7.

A raw material A2is composed of, for example, a gas containing Si and C, or a gas containing Ga and As. In this case, a seed crystal B2is composed of, for example, a SiC single crystal or a GaN single crystal.

In the crystal growth apparatus7, the gas-based raw material A2is supplied from below the crystal growth apparatus7into the crucible63via the second gas introduction part66and the first gas introduction part64, and is discharged to the outside of the crucible63via the first gas discharge part65and the second gas discharge part67. A gas flow (arrows inside the furnace inFIG. 7) of the raw material A2directed from the first gas introduction part64to the first gas discharge part65occurs in the crucible63, and the raw material A2flows near a lower surface and an outer circumferential surface of the seed crystal B2. Thus, the seed crystal B2is grown.

In a case where the seed crystal B2is grown by a gas method, measuring a temperature of a sidewall of the crucible63is important for controlling decomposition of the raw material A2. According to the present embodiment, a temperature of an outer surface63aof the crucible63can be accurately measured, and an improvement in quality of a crystal can be realized.

Seventh Embodiment

FIG. 8is a sectional view schematically showing a constitution of a crystal growth apparatus8according to a seventh embodiment of the present disclosure. The crystal growth apparatus8of the seventh embodiment is different from that of the first embodiment in that a raw material is a liquid, and is subjected to crystal growth by a solution method. The components that are the same as those of the first embodiment will be given the same reference numbers as in the first embodiment, and different portions will be described below.

The crystal growth apparatus8is comprised of a crucible73that includes a container body71in which a raw material A3can be received and a lid part72on which a seed crystal B3can be mounted, and a support member74that is mounted on the lid part72and liftably supports a seed crystal B3in the crucible73. The support member74is, for example, a graphite rod, and the seed crystal B3is mounted on a lower end thereof. In other words, the seed crystal B3is mounted on the lid part72via the support member74.

The raw material A3is composed of, for example, a liquid containing Si and C, or a liquid containing Si. In this case, the seed crystal B3is composed of, for example, a SiC single crystal or a Si single crystal.

In the crystal growth apparatus8, the seed crystal B3mounted on the lower end of the support member74is immersed in the raw material A3of the crucible73by lowering the support member74. In a state in which the seed crystal B3is immersed in the raw material A3, the raw material A3is heated, and then the seed crystal B3is pulled up. Thus, the seed crystal B3is grown.

Even in a case where the seed crystal B3is grown by a solution method, measuring a temperature of a sidewall of the crucible73is important for controlling crystal growth. According to the present embodiment, a temperature of an outer surface73aof the crucible73can be accurately measured, and an improvement in quality of a crystal can be realized.

While preferred embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the specific embodiments, and can be variously modified and changed without departing from the spirit and scope of the present disclosure which are defined in the claims.

For example, the crystal growth apparatus is comprised of the first heat insulating part and the second heat insulating part in the above embodiments, but it is not limited thereto and may include three or more heat insulating parts. In a case where the crystal growth apparatus includes three or more heat insulating parts, at least one first through-hole penetrating in a thickness direction is provided in each of the three or more heat insulating parts.

Further, in the above embodiments, the first heat insulating part is movably provided, and the second heat insulating part is fixed to the furnace body. However, without being limited thereto, the first heat insulating part may be fixed to the furnace body, and the second heat insulating part may be movably provided. Furthermore, both the first heat insulating part and the second heat insulating part may be movably provided. In this case, the moving mechanism can include the first moving mechanism that moves the first heat insulating part, and the second moving mechanism that moves the second heat insulating part.

Further, in the above embodiments, the first heat insulating part is movably provided along with the crucible. However, without being limited thereto, the first heat insulating part may be provided to be movable relative to the crucible. In this case, the moving mechanism may include the first moving mechanism that moves the crucible, and the second moving mechanism that moves the first heat insulating part.