JP2014047129A - Crystal growth apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a floating zone-type crystal growth apparatus capable of suppressing adhesion of a material evaporated from a floating zone to a tubular body.SOLUTION: A crystal growth apparatus 1 comprises: a tubular body 2 having a raw material rod 4 and a seed crystal rod 5 arranged in series in the internal space; and a laser source 3 for heating a boundary portion between the raw material rod 4 and the seed crystal rod 5 through the tubular body 2 to form a molten zone F. A gas jet nozzle 19e is separately arranged on the lower edge side of the tubular body 2 to the molten zone F in the internal space of the tubular body 2 and is provided to jet a gas toward an upper end side of the tubular body 2 so as to surround the molten zone F and generate an air flow along the internal surface of the tubular body 2.

Description

  The present invention relates to a crystal growth apparatus.

  As already known, a floating zone type crystal growth apparatus is used as one of methods for growing a single crystal or a polycrystal (see, for example, Patent Document 1).

  As shown in FIG. 5, this type of crystal growing apparatus 31 includes a tubular body 32 such as a quartz tube and a heating means 33 such as a laser source. In the internal space of the tubular body 32, a raw material rod 34 and a seed crystal rod 35 are arranged in series in contact with each other. The heating means 33 heats the boundary between the raw material rod 34 and the seed crystal rod 35 via the tubular body 32. Then, the boundary between the raw material rod 34 and the seed crystal rod 35 is melted by the heating means 33 to form a melted portion F ′ (floating zone). When the raw material rod 34 and the seed crystal rod 35 are moved downward with respect to the tubular body 32 and the heating means 33, the melting part F ′ moves on the raw material rod 34. As a result, when a part of the raw material rod 34 is melted and then solidified, crystals are grown on the end portion of the seed crystal rod 35.

JP 2007-145629 A

  By the way, the crystal growth apparatus having such a configuration has the following problems. That is, due to the heating by the heating unit 33, a part of the sample evaporates in the melting part F ', and it adheres to the inner surface of the tubular body 32 around the melting part F'. Then, this deposit increases with the passage of time, and due to this influence, the heating energy passing through the tubular body 32 gradually decreases. For this reason, in order to carry out stable crystal growth for a long time, a means such as increasing the output of the heating means 33 is required. In addition, the image of the observation camera provided for confirming the melted state of the melted part F ′ is also not clear as time passes, which may make it difficult to confirm the melted state.

  As countermeasures against the deposits on the tubular body 32, means such as frequent cleaning of the tubular body 32 and periodic replacement of the inner tubular body 32 with the tubular bodies 32 being doubled can be considered. Therefore, labor and equipment are required for management and maintenance, which leads to an increase in manufacturing cost.

  In view of the above circumstances, an object of the present invention is to suppress adhesion of a substance evaporated from a floating zone to a tubular body in a floating zone type crystal growing apparatus.

  The crystal growth apparatus of the present invention for solving the above problems includes a tubular body in which a raw material rod and a seed crystal rod are arranged in series in an internal space, and a boundary portion between the raw material rod and the seed crystal rod via the tubular body In the crystal growing apparatus, the tubular body is provided with a heating unit that heats the boundary portion and the molten portion formed by melting the boundary portion by moving the heating unit moves on the raw material rod. The other end of the tubular body is disposed in an inner space of the tubular body so as to be separated from one end side of the tubular body with respect to the melting portion, and surrounds the molten portion and generates an air flow along the inner surface of the tubular body. Gas ejecting means for ejecting gas toward the side is provided.

  If it is this structure, while enclosing a fusion | melting part (floating zone), the airflow along the inner surface of a tubular body will flow from the one end side of a tubular body to the other end side. Due to this air flow, the substance evaporated from the melted portion is suppressed from diffusing to the inner surface side of the tubular body, and flows to the other end side of the tubular body. Therefore, in the crystal growing device of the present invention, it is possible to suppress the substance evaporated from the melting part from adhering to the inner surface of the tubular body.

  Said structure WHEREIN: The said gas ejection means may eject the said gas in the direction inclined in the circumferential direction side with respect to the axial direction of the said tubular body.

  For example, when a plurality of jet outlets jet gas along the axial direction of the tubular body as the gas jetting means, no gas is jetted between the jet outlets, and in the axial space between the jet outlets, There may be little airflow. On the other hand, when a plurality of jet outlets as gas jetting means jet gas in a direction inclined to the circumferential direction side with respect to the axial direction of the tubular body, an axial space between the jet outlets is provided. In addition, an air flow is generated by the gas ejected from the ejection port. Accordingly, an air flow that surrounds the melting portion and along the inner surface of the tubular body is easily formed continuously in the circumferential direction. Thereby, adhesion of the evaporated substance from the melting part to the inner surface of the tubular body can be efficiently suppressed. Further, in this case, the airflow that surrounds the melting portion and along the inner surface of the tubular body is a spiral airflow.

  Further, when the gas ejection means ejects air along the axial direction of the tubular body, even if the ejection speed from the gas ejection means is increased, the distance from the gas ejection means to the exhaust portion is shortened. The exhaust cannot catch up, and the ejected air tends to stay. For this reason, the velocity of the airflow along the inner surface of the tubular body cannot be increased while surrounding the melting portion. On the other hand, when gas is ejected in a direction inclined to the circumferential side with respect to the axial direction of the tubular body, even if the ejection speed from the gas ejection means is increased, the gas ejection means to the exhaust section Since the distance becomes longer, exhaust is performed sequentially. For this reason, while enclosing a fusion | melting part, the speed of the airflow along the inner surface of a tubular body can be enlarged. This makes it possible to more reliably suppress the evaporation substance from the melting part from adhering to the inner surface of the tubular body.

  In any one of the configurations described above, the gas jetting unit may jet the gas in a direction inclined toward the outer diameter side with respect to the axial direction of the tubular body.

  With this configuration, the gas jetting means surrounds the melting portion and the air flow along the inner surface of the tubular body is applied to the inner surface of the tubular body as compared with the case where the gas ejecting means ejects gas along the axial direction of the tubular body. It is more certain that it will flow along. Accordingly, it is possible to more reliably suppress the evaporation substance from the melting portion from adhering to the inner surface of the tubular body.

  In any one of the above-described configurations, a path for supplying the gas may be provided in the internal space of the tubular body in which the melting portion exists, in addition to the path for supplying the gas to the gas ejection unit.

  With this configuration, it is possible to share a means for supplying gas to the internal space of the tubular body in which the melted portion exists with respect to the conventional crystal growth apparatus. Costs required can be reduced. Moreover, it becomes possible to adjust the pressure of gas separately by the path which supplies gas to a gas ejection means, and the path which supplies gas to the internal space of the tubular body in which a fusion | melting part exists. By this separate pressure adjustment, it can be expected to more effectively suppress the adhesion of the evaporated substance from the melting part to the inner surface of the tubular body.

  In any one of the above-described configurations, an annular air intake unit may be provided in the internal space of the tubular body so as to be spaced apart from the other end side of the tubular body with respect to the melted portion. Good.

  If it is this structure, the air flow which encloses a fusion | melting part and follows the inner surface of a tubular body will be suck | inhaled by the suction means. Thereby, while disturbing the air flow along the inner surface of the tubular body while surrounding the melting portion, it is more reliably flowed from one end side to the other end side of the tubular body. Accordingly, it is possible to more reliably suppress the evaporation substance from the melting portion from adhering to the inner surface of the tubular body.

  In any one of the configurations described above, the velocity of the air flow generated by the gas ejected from the gas ejecting means may be larger than the diffusion rate of the evaporated substance from the melting portion.

  If it is this structure, it will be suppressed more reliably that the substance which evaporated from the fusion | melting part by the air flow along the inner surface of a tubular body is diffused to the inner surface side of a tubular body while enclosing a fusion | melting part. Accordingly, it is possible to more reliably suppress the evaporation substance from the melting portion from adhering to the inner surface of the tubular body.

  In any of the above configurations, the crystal to be grown may be a single crystal.

  If it is this structure, the above-mentioned effect can be enjoyed with the crystal | crystallization apparatus which grows a single crystal.

  ADVANTAGE OF THE INVENTION According to this invention, in the floating zone type crystal growth apparatus, the adhesion to the tubular body of the substance evaporated from the floating zone can be suppressed.

It is an axial direction sectional view showing the important section of the crystal growth device concerning an embodiment of the present invention. It is an axial direction sectional view showing the main part of a tubular body. (A) is the sectional view on the AA line of FIG. 2, (B) is sectional drawing on the BB line of FIG. It is typical sectional drawing in the XX line arrow of FIG. It is an axial sectional view showing a main part of a conventional crystal growth apparatus.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows a main part of a crystal growth apparatus according to an embodiment of the present invention. The crystal growing apparatus 1 is a floating zone type, and in this embodiment, grows a single crystal.

  The crystal growing apparatus 1 includes a tubular body 2 and a laser source 3 as a heating means as main components.

  In the internal space of the tubular body 2, the raw material rod 4 and the seed crystal rod 5 are arranged in series in contact with each other. In this embodiment, the raw material bar 4 is not a single crystal, and the seed crystal bar 5 is a single crystal. The raw material rod 4 is attached to the lower end of the upper crystal drive shaft 6 extending in the vertical direction from above, and the seed crystal rod 5 is attached to the upper end of the lower crystal drive shaft 7 extending in the vertical direction from below. The upper crystal drive shaft 6 and the lower crystal drive shaft 7 are disposed in an airtight manner with respect to the support members 8 and 9. The upper crystal drive shaft 6 and the lower crystal drive shaft 7 are airtightly disposed so as to be rotatable and movable up and down with respect to the support members 8 and 9 by a drive means such as a servo motor (not shown). Further, the upper crystal driving shaft 6 and the lower crystal driving shaft 7 can be synchronized with each other or relatively rotated when rotating.

  The tubular body 2 is supported by support members 8 and 9 (for the sake of easy understanding, these boundaries are indicated by dotted lines). The tubular body 2 is attached to the support members 8 and 9 via fittings 10 and 11 that fit into the end portions of the tubular body 2 and abut against the end surfaces of the support members 8 and 9. The fastening tools 12 and 13 having inner flange portions that abut against the outer flange portions of the mounting tools 10 and 11 are screwed to the end portions of the support members 8 and 9, so that the mounting tools 10 and 11 are attached to the support members 8 and 9. It is fixed.

  If the screw connection of the fastening tools 12 and 13 is released, the tubular body 2 can be detached from the support members 8 and 9 together with the attachment tools 10 and 11. Such removal of the tubular body 2 is performed when the raw material rod 4 and the seed crystal rod 5 are installed or when the grown single crystal is taken out. The support members 8 and 9 and the fixtures 10 and 11 are sealed by O-rings 14 and 15, and the fixtures 10 and 11 and the tubular body 2 are sealed by O-rings 16 and 17. .

  The support member 9 has a cylindrical portion 9a on the inner peripheral side where the lower crystal drive shaft 7 moves up and down. The cylindrical portion 9a is provided with an air supply port 9b. The support member 8 has a cylindrical portion 8a on the inner peripheral side where the upper crystal drive shaft 6 moves up and down. The cylindrical portion 8a is provided with an exhaust port 8b.

  During the operation of the crystal growing apparatus 1, gas is supplied from the air supply port 9 b to the internal space of the tubular body 2 via the internal space of the cylindrical portion 9 a, and this gas flows through the internal space of the tubular body 2. The air is mainly exhausted from the exhaust port 8b via the internal space of the cylindrical portion 8a.

This gas is an inert gas such as helium, argon, or nitrogen when the single crystal is prevented from reacting with oxygen in the air, and it is desired to grow the single crystal by reacting with some gas (for example, oxygen). In some cases, the gas or a mixed gas containing a certain amount of the gas is used.

  A gas supply source such as a gas cylinder (not shown) is connected to the air supply port 9 b of the support member 9. An exhaust means such as a vacuum pump (not shown) is connected to the exhaust port 8 b of the support member 8. Depending on the type of gas discharged from the exhaust port 8b, a means for opening to the atmosphere may be connected.

  Further, the cylindrical portion 8a is provided with a water supply port 8c and a drainage port 8d, and the cooling water supplied from the water supply port 8c is drained from the drainage port 8d via the annular channel 8e. The cylindrical portion 9a is provided with a water supply port 9c and a drainage port 9d, and the cooling water supplied from the water supply port 9c is drained from the drainage port 9d via the annular channel 9e. As a result, the O-rings 14 to 17 around the boundary between the support members 8 and 9 and the tubular body 2 are cooled, and heat is prevented from being conducted upward or downward from the support members 8 and 9.

  The laser source 3 heats and melts the boundary between the raw material rod 4 and the seed crystal rod 5 through the tubular body 2 to form a melted portion F (floating zone). In this embodiment, the laser source 3 is a semiconductor laser. It is the used laser irradiation apparatus. As shown in FIG. 4, in the present embodiment, the laser source 3 has 5 circumferentially equidistantly spaced (72 °) around the tubular body 2 around the axis of the raw material rod 4 and the seed crystal rod 5. Individually arranged. A laser beam damper 18 is disposed at an opposite position across the tubular body 2 of the laser source 3. The laser beam damper 18 receives a region of the laser light L from the laser source 3 that does not hit the melting portion F of the raw material rod 4 and the seed crystal rod 5, and when the melting portion F is broken, the laser beam L To receive.

  As shown in FIG. 1, the tubular body 2 has a main body portion 19, an upper connecting portion 20, and a lower connecting portion 21 as main components (for easy understanding, the boundaries are indicated by dotted lines). ing). In this embodiment, these are comprised by another member, the main-body part 19 of the tubular body 2 is a product made from quartz glass, and the upper side and the lower side connection part 21 are made from stainless steel. The upper end portion of the main body portion 19 is fitted with the lower end portion of the upper connecting portion 20 on the outer peripheral side, and is sealed with an O-ring 22 therebetween. On the other hand, the lower end portion of the main body portion 19 is fitted with the upper end portion of the lower connecting portion 21 on the outer peripheral side, and is sealed with an O-ring 23 therebetween.

  As shown in FIG. 2, the main body portion 19 of the tubular body 2 includes a large diameter cylindrical portion 19a, a first small diameter cylindrical portion 19b formed on the inner peripheral side of the large diameter cylindrical portion 19a, and a second small diameter cylindrical portion 19c. And are the main components. 2 corresponds to the lower side of FIG. 1, and the right side of FIG. 2 corresponds to the upper side of FIG. 1. In the following description, the description will be made in the vertical direction of FIG.

  The lower end (left side in FIG. 2) of the large diameter cylindrical portion 19a and the lower end of the first small diameter cylindrical portion 19b are at the same position in the axial direction of the tubular body 2. The upper end of the first small diameter cylindrical portion 19b is connected to the inner peripheral surface of the large diameter cylindrical portion 19a at the first radial direction portion 19d. The surface connected to the inner peripheral surface of the first small-diameter cylindrical portion 19b in the first radial direction portion 19d gradually increases in diameter as it moves upward. That is, the axial cross section of the surface connected to the inner peripheral surface of the first small diameter cylindrical portion 19b in the first radial direction portion 19d has a curvature. Thereby, even if the substance evaporated from the melting part F adheres to this surface, it is easy to peel off to the lower side. On the other hand, the surface connected to the outer peripheral surface of the first small-diameter cylindrical portion 19b in the first radial direction portion 19d extends substantially along the radial direction.

  The first radial direction portion 19d is provided with a gas ejection port 19e that functions as a gas ejection means. As shown in FIG. 3A, the gas ejection ports 19e are a plurality of through holes formed at equal intervals in the circumferential direction in the first small diameter cylindrical portion 19b. Each of the gas ejection ports 19e has a linear central axis, and the central axis extends in a direction inclined toward the outer diameter side with respect to the axial direction of the tubular body 2 as it moves upward (see FIG. 2). Moreover, as shown to FIG. 3 (A), each center axis | shaft of the gas ejection port 19e is extended in the direction inclined in the circumferential direction side with respect to the axial direction of the tubular body 2 as it shifts to the upper side. About all the several gas jet nozzles 19e, the central axis is inclined and extended in the same circumferential direction side (out of two circumferential directions) with respect to the axial direction of the tubular body 2 as it moves upward.

  As shown in FIG. 1, the gas ejection port 19 e is arranged in the internal space of the tubular body 2 so as to be spaced apart from the lower end side of the tubular body 2 with respect to the melting portion F, and gas is directed toward the upper end side of the tubular body 2. Erupts. The gas ejected from the gas ejection port 19e surrounds the melting portion F and generates an air flow along the inner surface of the tubular body 2. The gas ejected from the gas ejection port 19 e is the same type as the gas supplied from the air supply port 9 b of the support member 9 to the internal space of the tubular body 2.

  As shown in FIG. 2, the upper end (the right side in FIG. 2) of the large diameter cylindrical portion 19 a and the upper end of the second small diameter cylindrical portion 19 c are at the same position in the axial direction of the tubular body 2. The upper end of the second small diameter cylindrical portion 19c is connected to the inner peripheral surface of the large diameter cylindrical portion 19a at the second radial direction portion 19f. The second radial direction portion 19f has a substantially uniform thickness and extends in the radial direction. As shown in FIG. 3B, the second radial portion 19f is provided with a plurality of through holes 19g at equal intervals in the circumferential direction. And the inlet port 19h opened to the lower side of the tubular body 2 is formed between the lower end of the 2nd small diameter cylindrical part 19c, and the internal peripheral surface of the large diameter cylindrical part 19a. The intake port 19h has a continuous annular shape and functions as an intake means.

  As shown in FIG. 1, the air inlet 19 h is disposed in the inner space of the tubular body 2 so as to be spaced apart from the melting portion F toward the upper end side of the tubular body 2 and sucks gas. The gas ejected from the gas ejection port 19e is sucked mainly by the intake port 19h.

  The upper connecting portion 20 of the tubular body 2 includes a thin cylindrical portion 20a whose upper end is attached to the support member 8, and a double cylindrical portion 20b whose upper end is connected to the thin cylindrical portion 20a and whose lower end is attached to the main body portion 19. The The double cylindrical portion 20b has an outer cylindrical portion 20c and an inner cylindrical portion 21d whose upper ends are connected to each other. The lower end portion of the outer cylindrical portion 20c is fitted with the upper end portion of the large-diameter cylindrical portion 19a of the main body portion 19 on the inner peripheral side, and has a large diameter on the lower surface of the step portion adjacent to the lower end portion of the outer cylindrical portion 20c. The upper end surface of the cylindrical part 19a contacts. A tapered surface is formed between the inner peripheral surface of the outer cylindrical portion 20c and the lower surface of the step portion. The lower end surface of the inner cylindrical portion 20 d abuts on the upper end surface of the second small diameter cylindrical portion 19 c of the main body portion 19.

  The lower connecting portion 21 of the tubular body 2 includes a thin cylindrical portion 21a whose lower end is attached to the support member 9, and a double cylindrical portion 21b whose lower end is connected to the thin cylindrical portion 21a and whose upper end is attached to the main body portion 19. Is done. The double cylindrical portion 21b has an outer cylindrical portion 21c and an inner cylindrical portion 21d whose lower ends are connected to each other. The upper end portion of the outer cylindrical portion 21c is fitted with the lower end portion of the large diameter cylindrical portion 19a of the main body portion 19 on the inner peripheral side, and has a large diameter on the upper surface of the step portion adjacent to the upper end portion of the outer cylindrical portion 21c. The lower end surface of the cylindrical part 19a contacts. Another step portion is formed between this step portion and the lower inner peripheral surface of the outer cylindrical portion 21c. Then, the upper end surface of the inner cylindrical portion 21 d abuts on the lower end surface of the first small diameter cylindrical portion 19 b of the main body portion 19.

  An exhaust port 20 e is provided in the double cylindrical portion 20 b of the upper connecting portion 20, and an air supply port 21 e is provided in the double cylindrical portion of the lower connecting portion 21. An exhaust means such as a vacuum pump (not shown) is connected to the exhaust port 20 e of the upper connecting portion 20. This exhaust means may be shared with the exhaust means connected to the exhaust port 8b of the support member 8, or may be separate. However, in any case, it is preferable that the exhaust pressure can be adjusted separately at the exhaust port 20e and the exhaust port 8b. A gas supply source such as a gas cylinder (not shown) is connected to the air supply port 21 e of the lower connecting portion 21. This gas supply source may be shared with the gas supply source connected to the air supply port 9b of the support member 9, or may be different. However, in any case, it is preferable that the pressure can be adjusted separately at the air supply port 21e and the air supply port 9b.

  During the operation of the crystal growing apparatus 1, gas is supplied from the air supply port 21e to the gas ejection port 19e of the main body 19 via the substantially cylindrical flow path R1. The gas ejected from the gas ejection port 19e is mainly sucked into the intake port 19h and is exhausted from the exhaust port 20e via the substantially cylindrical flow path R2. The flow path R1 includes a space between the outer cylindrical portion 21c and the inner cylindrical portion 21d of the double cylindrical portion 21b of the lower connecting portion 21, a large diameter cylindrical portion 19a and a first small diameter cylindrical portion 19b of the main body portion 19. It is formed in the space between. The gas jet port 19e side in the flow channel R1 has a larger cross-sectional area of the flow channel than the air supply port 21e side, but this constitutes an air reservoir (buffer) from the gas jet port 19e. Stabilizes gas ejection. The flow path R2 includes the space between the outer cylindrical portion 20c and the inner cylindrical portion 20d of the double cylindrical portion 20b of the upper connecting portion 20, the large diameter cylindrical portion 19a and the second small diameter cylindrical portion 19c of the main body portion 19. It is formed in the space between.

  Further, the double cylindrical portion 20b of the upper connecting portion 20 is provided with a water supply port 20f and a drainage port 20g, and the cooling water supplied from the water supply port 20f is drained via the annular channel 20h. Drained from the mouth 20g. The double cylindrical portion 21b of the lower connecting portion 21 is also provided with a water supply port 21f and a water discharge port 21g, and the cooling water supplied from the water supply port passes through the annular channel 21h, and the water discharge port 21g. Drained from. As a result, the O-rings 22 and 23 that seal between the upper and lower connecting portions 20 and 21 and the main body portion 19 are cooled, and heat is conducted above and below the upper and lower connecting portions 20 and 21. To suppress.

  Thus, the path for supplying the gas to the internal space in the main body part 19 where the melted part F exists is the path from the air supply port 21e of the tubular body 2 through the gas jet port 19e, and the air supply of the support member 9 There are two systems of paths that pass from the opening 9b to the inner peripheral side of the first small-diameter cylindrical portion 19b. In addition, the path through which the gas is discharged from the internal space in the main body 19 where the melted part F exists is a path from the intake port 19h to the exhaust port 20e of the tubular body 2 and the inner peripheral side of the second small diameter cylindrical portion 19c. There are two systems of paths through the exhaust port 8b of the support member 8.

  The crystal growth apparatus 1 configured as described above is operated as follows.

  In the internal space of the tubular body 2, a boundary portion between the raw material rod 4 and the seed crystal rod 5 that are in contact with each other is installed at a position where the laser beams L of the plurality of laser sources 3 are concentrated.

  On the other hand, water is supplied to the water supply ports 8 c and 9 c of the support members 8 and 9 and the water supply ports 20 f and 21 f of the upper and lower connecting portions 20 and 21. Then, air is supplied to the air supply port 9 b of the support member 9 and the air supply port 21 e of the lower connection portion 21, and exhausted from the exhaust port 8 b of the support member 8 and the exhaust port 20 e of the upper connection portion 20.

  Then, irradiation of the laser beam L from the laser source 3 is started. Thereby, the boundary part of the raw material stick | rod 4 and the seed-crystal stick | rod 5 is heated and fuse | melted, and the fusion | melting part F (floating zone) is formed.

  From this state, the upper crystal drive shaft 6 and the lower crystal drive shaft 7 are rotated or relatively rotated in synchronization with each other and slowly moved downward in synchronization. Thereby, the raw material rod 4 and the seed crystal rod 5 are slowly moved with respect to the tubular body 2 and the laser source 3, and the melting portion F moves slowly on the raw material rod 4. Thereby, when a part of the raw material rod 4 is melted and then solidified, a single crystal is grown on the end portion of the seed crystal rod 5.

  While the melted part F is formed, the substance evaporated from the melted part F diffuses around. On the other hand, in this embodiment, since the gas ejection port 19e ejects gas toward the upper end side of the tubular body 2, while enclosing the fusion | melting part F with the gas ejected from this gas ejection port 19e, Airflow along the inner surface of the tubular body 2 is generated. Due to this air flow, the evaporating substance from the melting part F is suppressed from diffusing to the inner surface side of the tubular body 2, and flows toward the upper end side of the tubular body 2. Therefore, in the crystal growth apparatus 1 of this embodiment, it can suppress that the evaporation substance from the fusion | melting part F adheres to the inner surface of the tubular body 2. FIG.

  Further, as the straight central axis of the gas jet port 19e moves upward, it extends in a direction inclined to the outer diameter side with respect to the axial direction of the tubular body 2 and is circumferential with respect to the axial direction of the tubular body 2. It extends in a direction inclined to the direction side. Thereby, gas is ejected from the gas ejection port 19e in a direction inclined toward the outer diameter side with respect to the axial direction of the tubular body 2 and in a direction inclined toward the circumferential direction side with respect to the axial direction of the tubular body 2. (See FIG. 4).

  As the gas is ejected from the gas ejection port 19e in a direction inclined toward the outer diameter side with respect to the axial direction of the tubular body 2, it is more certain that the generated airflow flows along the inner surface of the tubular body 2. . Gas is ejected from the gas ejection port 19e in a direction inclined in the circumferential direction with respect to the axial direction of the tubular body 2, so that the gas is ejected from the gas ejection port 19e also in the axial space between the gas ejection ports 19e. An air flow is generated by the generated gas. Therefore, the generated airflow is easily formed continuously in the circumferential direction. Accordingly, it is possible to efficiently suppress the adhesion of the evaporated substance from the melting portion F to the inner surface of the tubular body 2.

  Further, since the gas is ejected from the gas outlet 19e in a direction inclined in the circumferential direction with respect to the axial direction of the tubular body 2, the distance from the gas outlet 19e to the intake port 19h is increased. Even if the gas ejection speed from the outlet 19e is increased, the gas is exhausted sequentially. For this reason, while enclosing the fusion | melting part F, the speed of the airflow along the inner surface of the tubular body 2 can be enlarged. This makes it possible to reliably suppress the evaporation substance from the melting portion F from adhering to the inner surface of the tubular body 2.

  Note that a spiral airflow is generated along the inner surface of the large-diameter cylindrical portion 19a of the main body portion 19 toward the upper end of the tubular body 2 as a whole by the gas ejected from the plurality of gas ejection ports 19e.

  In the present embodiment, the velocity of the air flow generated by the gas ejected from the gas ejection port 19e is higher than the diffusion rate of the evaporated substance from the melting portion F. For this reason, it is suppressed more reliably that the substance which evaporated from the fusion | melting part F to the inner surface side of the tubular body 2 with the air flow along the inner surface of the tubular body 2 is surrounded more reliably. Therefore, the suppression of the adhesion of the evaporated substance from the melted portion F to the inner surface of the tubular body 2 becomes more reliable.

  Further, the airflow surrounding the melting portion F and along the inner surface of the tubular body 2 is mainly sucked into the intake port 19h. Thereby, it is suppressed that the airflow along the inner surface of the tubular body 2 surrounds the melted portion F, and flows more reliably from the lower side to the upper side. Therefore, the suppression of the adhesion of the evaporated substance from the melted portion F to the inner surface of the tubular body 2 becomes more reliable.

  In addition, since the tubular body 2 can be detached from the support members 8 and 9, the conventional crystal growth apparatus and the support members 8 and 9 can be used in common, so the cost required for replacement with the conventional crystal growth apparatus. Can be reduced. Moreover, since the path for supplying the gas to the gas outlet 19e and the path for supplying the gas to the internal space of the tubular body 2 where the melted portion F exists are different, the pressure of the gas is adjusted separately in these paths. It is possible. By this separate pressure adjustment, it can be expected that the evaporation substance from the melting portion F is more effectively suppressed from adhering to the inner surface of the tubular body 2.

  In the above embodiment, the intake port 19h as the intake means has a continuous annular shape, but is not limited thereto, and may be an intermittent annular shape. For example, the through holes 19g arranged in an annular shape It may be something like

  In the said embodiment, although the main-body part 19, the upper side connection part 20, and the lower side connection part 21 were comprised by the separate member, it is not limited to this, For example, these are made into one member with quartz glass, for example. You may comprise as.

  In the above embodiment, the laser source 3 is used as the heating means. However, the present invention is not limited to this, and the boundary between the raw material rod 4 and the seed crystal rod 5 is heated via the tubular body 2. For example, a combination of an ellipsoidal mirror and an infrared lamp may be used.

  Moreover, in the said embodiment, although the crystal growing apparatus 1 grew a single crystal, it may grow a polycrystal.

DESCRIPTION OF SYMBOLS 1 Crystal growth apparatus 2 Tubular body 3 Laser source (heating means)
4 Raw material rod 5 Seed crystal rod 19 Body 19e Gas outlet (gas ejection means)
19h Air intake (air supply means)
F Melting zone

Claims (7)

A tubular body in which the raw material rod and the seed crystal rod are arranged in series in the internal space, and a heating means for heating the boundary between the raw material rod and the seed crystal rod via the tubular body, In the crystal growth apparatus in which a crystal is grown by moving a melted part formed by melting the boundary part on the raw material rod,
The tubular body is disposed in an inner space of the tubular body and is spaced apart from one end side of the tubular body with respect to the melting portion, and surrounds the melting portion and generates an air flow along an inner surface of the tubular body. A crystal growth apparatus, characterized in that gas ejection means for ejecting gas toward the other end side of the crystal is provided.   The crystal growth apparatus according to claim 1, wherein the gas jetting unit jets the gas in a direction inclined to a circumferential side with respect to an axial direction of the tubular body.   The crystal growth apparatus according to claim 1, wherein the gas jetting unit jets the gas in a direction inclined toward an outer diameter side with respect to an axial direction of the tubular body.   4. The path according to claim 1, wherein a path for supplying the gas is provided in an internal space of the tubular body in which the melted portion exists, in addition to the path for supplying the gas to the gas ejection unit. Crystal growth device.   5. The annular intake device according to claim 1, further comprising an annular intake unit that is disposed in the internal space of the tubular body so as to be spaced apart from the melted portion on the other end side of the tubular body and sucks the gas. The crystal growth apparatus described in 1.   The crystal growth apparatus according to any one of claims 1 to 5, wherein a velocity of the air flow generated by the gas ejected from the gas ejection means is larger than a diffusion rate of the evaporating substance from the melting portion.   The crystal growing apparatus according to claim 1, wherein the crystal to be grown is a single crystal.

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