JP5195301B2 - Single crystal pulling device - Google Patents

Description

  The present invention relates to an apparatus for producing single crystals such as oxides, fluorides, and metal alloys used for so-called laser optical elements, nonlinear optical elements, medical scintillators, piezoelectric elements, giant magnetostrictive elements, and the like. More specifically, a pulling method for obtaining a desired crystal material while pulling a molten material from a hole provided at the lower end of the crucible, particularly a so-called micro pulling (μ-pD) method for obtaining a fiber-like single crystal. The present invention relates to a single crystal pulling apparatus used in a manufacturing method.

  A pull-out hole is formed in the lower end of the crucible holding the heated and melted raw material, crystal nuclei (hereinafter referred to as seeds) are brought into contact with the raw material melt leaked from the hole, and leakage of the raw material from the hole is caused. A so-called pulling-down method (see Patent Documents 1 to 3) is known in which a single crystal that grows using the seed as a nucleus is obtained by pulling down the seed. A single crystal obtained by this method has a smaller crystal diameter than a single crystal obtained by a so-called pulling method represented by a conventionally known CZ method. However, as a method for obtaining a single crystal having a short time required for crystal growth and excellent in crystallinity at a low cost as compared with the CZ method, it is necessary to modify the actual manufacturing equipment in terms of hardware and various single units. Application to crystals has been studied.

  In the pulling-down method, there is a so-called micro-pulling-down method as a method for obtaining a fiber crystal having higher crystallinity and maintaining a high crystal growth rate. Using this method, a fluoride single crystal such as calcium fluoride used for an optical material for excimer laser, or an oxide single crystal such as alumina or calcia, and also a giant magnetostrictive material exemplified by so-called terphenol D Manufacturing conditions for single crystals are being studied.

JP 2003-095783 A JP 2006-206351 A JP-T-2006-347789

  As the micro-pulling method, a so-called high-quality single crystal is obtained, and a method of controlling the shape of the single crystal by utilizing the shape of the hole provided in the crucible as shown in Patent Document 1 is known. It is also known to consider the wettability between the melt and the material constituting the crucible hole through which the melt passes in order to obtain a suitable drawing state from the hole of the raw material melt. Thus, considering the material of the crucible, a suitable drawing condition can be obtained. On the other hand, since the molten raw material is leaked or drawn out from the hole provided in the crucible, a single crystal is obtained. This may affect the condition inside or around the hole. When unevenness or the like is formed on the surface of the single crystal due to such an influence, it is necessary to perform post-processing on the surface to form a suitable surface state. However, depending on the single crystal to be obtained, the subsequent processing itself may be difficult. In addition, such post-processing leads to a reduction in the diameter of a single crystal that is actually used, an increase in steps due to the presence of the post-processing, and an increase in cost.

  The present invention has been made in view of the above circumstances, and can be suitably controlled for the surface state of a fiber-like single crystal, and can be used for a micro-pulling-down method that enables production of a single crystal without the need for post-processing. The purpose is to provide a single crystal manufacturing apparatus.

  In order to solve the above-described problems, the fiber-shaped single crystal manufacturing apparatus according to the present invention is made of a high-melting-point material capable of conducting high-frequency, and can hold a raw material melt therein. Holding a crucible having a drawable hole at the bottom, a heating coil arranged by winding the crucible and radiating a high frequency to the crucible, and a seed for determining a crystal orientation when the raw material melt is crystallized, A seed holder for pulling down the seed along a predetermined pulling axis passing through the hole of the crucible, and the raw material melt when the raw material melt is drawn from the hole around the hole in the opening of the hole A behavior suppressing member that suppresses the diameter expansion behavior in a plane perpendicular to the predetermined pull-down axis is arranged.

  In the above-described apparatus for pulling down the fiber-like single crystal, the behavior suppressing member is preferably a bowl-shaped member that protrudes from the crucible so as to wind the opening from the end where the hole in the crucible opens. In this case, the bowl-shaped member is preferably made of the same material as the crucible and formed as a part of the crucible. Further, it is more preferable that the flange-shaped member has a triangular shape with a protruding tip portion as a top portion in a cross section in a plane including an axis line in the protruding direction and a predetermined pulling axis. Alternatively, the behavior suppressing member may be configured by making the surface roughness different with respect to the inner surface of the crucible contacting the raw material melt. Alternatively, the behavior suppressing member may be configured of a member having wettability that is opposite to wettability of the inner surface of the crucible that is in contact with the raw material melt, with respect to the raw material melt. Note that these behavior suppressing members described above may have an orientation flat forming portion for forming orientation flats that can specify the crystal orientation in the fiber crystal. Or this behavior suppression member is good also as being arrange | positioned along the outer periphery of the end surface which the hole in a crucible opens. Alternatively, the behavior suppressing member may be disposed along the inner periphery of the hole opening in the crucible. Furthermore, in these apparatuses, it is more preferable that the upper end portion in the movable range along the predetermined pull-down axis of the seed holder is located in the internal space of the crucible.

  According to the present invention, it is possible to easily and reliably obtain a fiber-like single crystal having a smooth surface state and a desired shape. More specifically, according to the present invention, the surface tension of the raw material melt, or the wettability between the surface material such as a crucible in contact with the raw material melt at or around the hole and the wetness of the previous material melt. It is possible to suppress the uneasy behavior of the raw material melt. Therefore, it is possible to suppress the shape abnormality of the surface of the fiber-like single crystal due to such an uneasy behavior, and to process into a desired shape that does not require post-processing.

  Further, according to the present invention, when the wettability between the constituent material of the opening end of the hole and the raw material melt is large, the spread of the raw material melt at the hole opening end is divided within a specific range, and the hole opening end It becomes possible to define the cross-sectional shape of the fiber-like single crystal. Alternatively, according to the present invention, when the wettability between the constituent material of the opening end of the hole and the raw material melt is small, the raw material melt exhibits an unstable behavior at the open end of the hole, for example, by improving the wettability. It is possible to suppress the possibility of the occurrence and to define the cross-sectional shape of the fiber-like single crystal at the hole opening end. Specifically, by forming a so-called inner flange of a triangular pyramid with a convex downward section on the inner periphery side of the opening end, the so-called repelling effect on the raw material melt protruding from the opening end is suppressed. It is possible to do. At the same time, the degree of heating by the self-heating crucible is suppressed at the inner flange, and the effect of lowering the wettability accompanying the decrease in viscosity is obtained. Thereby, the influence of the repelling from the crucible on the raw material melt exiting the open end is suppressed, and a fiber-shaped single crystal having a desired shape can be obtained. Further, according to the present invention, a region having a different surface roughness is provided around the hole opening end, and the wettability between the raw material melt and the material such as the crucible is physically reduced at the boundary between the region and the hole opening. It may be different. That is, the wettability is controlled by a physical method to stabilize the meniscus of the raw material melt and prevent unnecessary spread of the raw material melt at the opening end of the hole. The effect of stabilizing is obtained. By making better use of these effects, it is possible to simultaneously form a so-called orientation flat that indicates, for example, the crystal orientation during single crystal formation.

  Further, according to the present invention, regarding so-called seed touch in which the seed is brought into contact with the raw material melt and the pulling-down process is started, various conditions related to the seed touch such as timing can be made constant. Accordingly, the behavior of the raw material melt at the hole opening end tends to be non-uniform, and the seed touch conditions can be stabilized. In particular, it is possible to always keep the positional relationship between the seed and the pulling-down end of the raw material melt at the time of seed touch. For this reason, it becomes possible to automate the operation required in the single crystal pulling process such as seed touch, which has conventionally been required to be visually observed, and the practicality as a fiber-like single crystal manufacturing apparatus is greatly enhanced. In addition, by stabilizing the conditions of seed touch and improving the surface state of the fiber-like single crystal described above, a fiber single crystal that can withstand practical use can be obtained from the initial growth start region. Therefore, the raw materials are effectively used, and the productivity as a single crystal manufacturing apparatus can be improved.

  An embodiment of the present invention will be described below with reference to the drawings. In the following drawings used to explain the embodiments of the present invention, only the portion of the raw material melt drawn out from the vicinity of the bottom surface of the crucible and the opening provided in the bottom surface, which is a characteristic configuration of the present invention, is extracted. Is shown enlarged. FIG. 1 is a diagram schematically showing an axial cross section of a conventional crucible and a fiber-like single crystal grown from a lower end portion of the crucible as a comparison with the present invention, and is a material having high wettability with respect to the crucible. This shows the case where the reduction is implemented. In the present specification, the so-called contact angle when the raw material melt is present on a flat plate material made of the same material and surface state as the hole opening of the crucible is 90 ° or more. Is defined as a material with low wettability, and the case of less than 90 ° is described as a material with high wettability.

  Here, in the same figure, a hole 11a is provided at the lower end of the crucible 11, but in the form shown in the figure, the diameter of the single crystal is stabilized from the lower end of the crucible 11 to the opening region of the hole 11a. The cylindrical part 11b for this is arrange | positioned. In the form shown in FIGS. 1 to 2C below, the case where the hole 11a is formed of a cylindrical inner surface and the opening has a circular shape for the purpose of obtaining a columnar (so-called fiber-like or rod-like) single crystal. Illustrated. Inside the crucible 11 is a raw material 9 in a molten state, that is, a raw material melt 9. When the raw material melt 9 is a material having high wettability, the raw material melt 9 is transmitted along the end surface of the cylindrical portion 11b and climbs up the outer peripheral surface because of the high wettability as shown in FIG. Indicates an event. The shape of the cross section perpendicular to the growth axis of the growth portion 9b of the single crystal portion 9a is affected by this climbing portion. For this reason, the said cross section will expand beyond the shape and magnitude | size of the surface of the opening edge part of the cylindrical part 11b, and will form the external shape according to the scooping area | region where shape control is not carried out. For this reason, it is not easy to make the outer diameter of the fiber-like single crystal obtained from the above configuration into a desired shape accurately or with good reproducibility.

  In this invention, the structure which regulates the area | region which the raw material melt spreads with respect to the end surface around the hole 11a of the cylindrical part 11b which affects the outer diameter of a single crystal is arranged. A more specific embodiment is shown in FIG. 2A. 2A is grown in the same manner as in FIG. 1 from the end and the end of the crucible 11, which is an embodiment of the present invention, in the same manner as in the embodiment and the embodiment shown in FIGS. 2B and 2C. A fiber-like single crystal is shown. Further, the same reference numerals are used for the same components as those shown in FIG. In the crucible 11 shown in FIG. 2A, a so-called bowl-shaped flange portion 11c in which the outer diameter of the end surface is enlarged in a plane perpendicular to the axis of the cylindrical portion 11b is arranged with respect to the opening end surface of the cylindrical portion 11b. . The amount of the raw material melt climbing up the cylindrical portion 11b is suppressed by the presence of the flange portion 11c, and accordingly, the raw material melt present in the vicinity of the opening end that can affect the outer surface of the crystal is reduced. A fiber-like single crystal is obtained in the state of the outer surface.

  The flange portion 11c is excellent in terms of ease of processing and maintaining the strength of the flange portion. However, since there is a raw material melt that climbs up the outer peripheral surface of the flange portion 11c even if it is small, it is slightly inferior in terms of outer diameter control. That is, from the viewpoint of substantially eliminating the raw material melt that climbs, it is preferable to eliminate the presence of the outer peripheral surface itself. The embodiment shown in FIG. 2B is configured from this viewpoint. That is, in the present embodiment, the flange portion 11d is formed such that, in a cross section along the axial direction, the cross section is triangular and the outer periphery is linear. In other words, in this embodiment, the flange portion 11d having the maximum outer peripheral diameter at the opening end surface is formed in such a manner that the outer peripheral diameter decreases as it moves away from the opening end surface of the cylindrical portion 11b in the axial direction. Yes. According to this embodiment, it is possible to substantially eliminate the raw material melt that climbs up the cylindrical portion 11b by appropriately determining the reduction rate of the outer peripheral diameter. Therefore, it is possible to stably obtain a fiber-like single crystal having a smooth outer surface and a desired outer diameter and excellent crystal quality.

  In the form shown in FIGS. 2A and 2B, the quality of the crystal is improved by controlling the area where the melt melts physically by controlling the wettability of the raw material melt with respect to the outer peripheral portion of the opening end face. Yes. However, the method for controlling the range in which the raw material melt spreads is not limited to this mode. FIG. 2C shows another embodiment for controlling the wet spreading range. In the embodiment shown in FIG. 2C, the wettability of the raw material melt with respect to the raw material melt with respect to the region where the raw material melt spreads and becomes a problem, specifically, the outer peripheral surface of the cylindrical portion 11b connected from the opening end surface. The coating 11e of the material which is inferior is applied. Thereby, the climbing of the cylindrical part 11b of the raw material melt 9 is suppressed, and a fiber-like single crystal corresponding to the outer diameter of the cylindrical part end face is obtained. In this embodiment, the coating 11e is applied to a region where it is desired to avoid wetting and spreading of the raw material melt. However, it is good also as bringing about the difference in wettability between these area | regions, for example by processing to the surface of these members, and making surface roughness differ. The coating 11e or a structure equivalent thereto may be disposed on the opening end face.

  Here, a modified example of the flange portion 11d will be described with reference to the drawings. 3A to 3D show a case where the angle between the side that can be contacted by the raw material melt 9 and the pull-down direction is made different in the triangular cross section of the flange portion 11d. In these drawings, only the configuration corresponding to the cylindrical portion 11b and the flange portion 11d in FIG. 1 and the like is schematically shown as an axial section and a planar state when viewed from below, and a prismatic fiber. A part of the crucible 11 for the purpose of growing a single crystal is shown. As the material having high wettability, the raw material melt 9 having a contact angle of 90 ° or more with respect to the material of the crucible 11 can be considered. In this case, as shown in these drawings, it is preferable to arrange the flange portion 11d on the outer peripheral side of the opening end face and increase the angle formed in the drawings as the contact angle decreases. In addition, the shape of the cross section perpendicular to the growth axis of the obtained fiber-like single crystal matches the shape of the crucible opening in these figures as viewed from below.

  Next, the second embodiment of the present invention for the case where the melt is small in wettability as the material for the fiber-like single crystal, specifically, the case where the contact angle is 90 ° or more is described. . Here, before describing this embodiment, the growth mode of the fiber-like single crystal when a conventional crucible is used will be described. In the forms shown in FIGS. 4 to 5C below, the hole 11a is formed from the inner periphery of the cylinder and the opening has a circular shape for the purpose of obtaining a columnar (so-called rod-like or fiber-like) single crystal. Is illustrated. Moreover, about FIG. 4, FIG. 5A, FIG. 5B, and FIG. 5C mentioned below, these examples are shown in the same manner as FIG. 1 about the crucible 11, the raw material melt 9, and the like. Further, FIG. 4 shows a shape that does not have the above-described cylindrical portion 11b that has been used most frequently for comparison and reference. In addition, for the same configuration as the configuration shown in FIG. 1 and the like, the same reference numerals are used to indicate these configurations. In the case of the raw material melt 9 having a low wettability, when passing through the hole 11a, a force away from the inner wall of the hole 11a, so-called repulsive force, is applied to the raw material melt 9. By leaving the opening of the hole 11a, this repulsive force on the raw material melt 9 disappears suddenly. For this reason, part of the raw material melt 9 in the hole 11a is pushed out of the opening where the repulsive force does not act due to the repulsive force acting just above the opening, and as a result, the outer diameter of the single crystal portion 9a is expanded. Will be allowed to. That is, the passage of the low-viscosity raw material melt 9 through the hole 11a is temporarily accelerated by this repulsive force. In the flow of the raw material melt 9, the momentum passing through the hole 11a is stopped by the upper end portion of the single crystal portion 9a waiting below, and as a result, the raw material melt 9 is accumulated in the upper end portion of the single crystal portion 9a. . Therefore, the outer shape and the like of the single crystal portion 9 are limited by this portion. Further, since the open end face of the crucible 11 exists immediately above the expanded area in the raw material melt, repulsive force is also received from the end face. The expanded diameter area is crushed by the repulsive force and further enlarges the expanded diameter portion. The amount of the raw material melt 9 to be extruded is influenced by its wettability, the state of the inner wall of the hole 11a, the processing state of the corner of the opening, the drawing speed, etc., and this is controlled in detail and evenly over the entire circumference of the crystal. It seems difficult to do.

  In the present embodiment, in order to suppress the influence of the repulsive force at the opening of the hole 11a due to the wettability described above on the outer diameter of the single crystal, the second flange protrudes downward in the axial direction from the periphery of the opening. 11f is arranged. A more specific embodiment is shown in FIG. 5A. In addition to the embodiment shown in FIG. 5B and FIG. 5C, FIG. 5A is grown from the end and the end of the crucible 11 according to the second embodiment of the present invention in the same manner as FIG. A fiber-like single crystal is shown. In the crucible 11 shown in FIG. 5A, the inner peripheral surface of the cylindrical portion 11b is extended on the axial end surface side with respect to the opening end surface of the cylindrical portion 11b, and the top portion extends in the axial direction with the extended portion as one side. A second flange portion 11f constituting a triangle that coincides with the end portion is disposed. In the second flange portion 11f, there is no opening end face that gives repulsive force to the raw material melt 9 that has come out of the opening, and the influence of the repulsive force received from the surface is first excluded.

  Further, the crucible 11 in this embodiment generates heat by a so-called high frequency supplied from a heating coil (not shown) arranged so as to wind the outer periphery of the crucible 11, and the heat is used to melt and melt the raw material. To maintain. Usually, this heating coil is disposed so as to wind the cylindrical portion of the main body of the crucible 11, and the second flange portion 11f exists outside the region surrounded by the heating coil. For this reason, the high frequency which can be transmitted from a heating coil falls from a main-body cylindrical part, and the degree of a heating becomes low. Furthermore, since the distance from the heating coil is also increased, the transmitted high frequency is attenuated and the heating efficiency is lowered. Also, so-called induction heat generation due to high frequency depends on the volume of the object in which high frequency induction occurs. For this reason, in the 2nd flange part 11f from which it leaves | separates from a heating area | region as it reaches a front-end | tip part, heating efficiency falls and thickness becomes thin, the emitted-heat amount falls as it reaches a front-end | tip part, and it connects with the crucible 11. A temperature gradient is generated in the second flange portion 11f from the portion to the tip portion. The expression of the wettability of the raw material melt 9 depends on the viscosity of the raw material melt 9, and the viscosity greatly depends on the temperature change in the vicinity of the melting point of the raw material. In the present invention, by developing a temperature gradient as described above, the viscosity of the raw material melt 9 is reduced when drawn out from the opening formed by the second flange portion 11f, thereby suppressing the expression of wettability. doing. Further, as described above, the presence of the cylindrical portion 11 b and the second flange portion 11 f gives a relatively steep temperature gradient region to the raw material melt 9. As a result, the solid-liquid interface (meniscus) 9b is located in the cylindrical space formed by these configurations. Therefore, when passing through the region, the outer shape of the single crystal portion 9a is defined by the inner wall of the cylindrical space.

  By the synergistic effect of the effect and the effect of eliminating the crucible opening end face described above and eliminating the influence of the repulsive force from the end face, in the present invention, in the raw material melt 9 drawn from the crucible 11, the change in the radial direction is substantially reduced. It can be eliminated. That is, by arranging the second flange portion 11f, it is possible to obtain a situation in which the behavior of the raw material melt 9 drawn out from the opening cannot be expanded in the radial direction. Therefore, the outer peripheral shape of the obtained fiber-like single crystal is based on the opening of the hole portion 11a as compared with that obtained from the configuration shown in FIG. 3, and the state of the outer surface of the crystal is smooth. In addition, a fiber-like single crystal having a desired outer diameter and excellent crystal quality can be stably obtained.

  In the second flange portion 11f in the embodiment shown in FIG. 5A, in the process of reaching the tip portion, the distance from the heating coil is increased, the heating coil is effectively separated from the heating region, and the heat generation volume is reduced. All three are affected. For this reason, when the temperature gradient becomes too large and the position of the solid-liquid boundary region 9b, which is the boundary portion between the raw material melt 9 and the single crystal portion 9a, is too close to the crucible 11 side, the second flange portion 11f It can be considered that it is difficult to lower it. In this case, as shown in FIG. 5B, the second flange portion 11b is formed so that the opening diameter continuously increases from the inner peripheral surface of the opening of the cylindrical portion 11b, and the cross-sectional triangle opposite to that in FIG. 5A is formed. You may comprise the 2nd collar part 11f so that it may become a shape. In the case of this configuration, the extent to which the distance from the heating coil is increased is suppressed from the configuration shown in FIG. 5A, and the arrangement of the growth portion 9b can be shifted away from the crucible 11 with a gentle temperature gradient. .

  5A and 5B, by eliminating the opening end face, the repulsive force applied to the raw material melt 9 from the opening end face is gradually reduced by the wettability of the raw material melt, and a temperature gradient is provided in the second flange portion 11f. By suppressing the wettability and controlling the position of the solid-liquid strengthening region 9b, the diameter of the raw material melt drawn out is physically controlled to improve the crystal quality. However, the method for controlling the suitable gradual reduction of the repulsive force on the raw material melt is not limited to this mode. FIG. 5C shows another form in which repulsive force generated at the opening end face is reduced. In the embodiment shown in FIG. 5C, a material coating that improves the wettability with respect to the raw material melt on the region near the opening of the inner wall of the hole 11a that applies repulsive force to the raw material melt and the opening end face. 11g is given. Thereby, the repulsive force from the inner wall of the cylindrical part 11b with respect to the raw material melt 9 does not change suddenly from the opening part, and the length of the cylindrical part 11f is set to a specific value, so that the solid-liquid boundary region 9b is It is possible to stably form the inside of the cylindrical portion 11b, and a fiber-like single crystal corresponding to the inner diameter of the opening of the cylindrical portion can be obtained. In this embodiment, the coating 11g is applied to the region where it is desired to avoid the addition of repulsive force to the raw material melt. For example, by processing the surface of these members, for example, by varying the surface roughness, etc. It is good also as bringing about the difference in wettability with respect to these area | regions. Moreover, if the thickness change of the part used as the heating object mentioned above is provided by arrange | positioning the said area | region in crucible opening vicinity, a temperature gradient will also be expressed simultaneously and the effect which suppresses expression of wettability will also be acquired.

  As described above, in the present invention, in the case of a combination in which the wettability of the raw material melt is increased with respect to the inner surface of the crucible or the like, the periphery of the hole with respect to the outer end surface where the opening of the hole of the crucible is formed. More specifically, a saddle-shaped member is disposed so as to wind the opening around the end surface, a region having a surface roughness different from that of the inner surface, or a member having different wettability is disposed. It is said. These configurations act as a behavior suppressing member for suppressing the diameter expansion behavior of the raw material melt in a plane perpendicular to the predetermined pulling axis. In the case of a combination in which the wettability of the raw material melt is reduced with respect to the inner surface of the crucible or the like, the opening is wound around the inner peripheral surface or the end surface continuous from the inner peripheral surface of the opening of the crucible hole. As described above, the hook-shaped member is disposed, a region having a surface roughness different from that of the inner surface is disposed, or a member having different wettability is disposed. These structures act as a behavior suppressing member for suppressing the diameter expansion behavior of the raw material melt in a plane perpendicular to a predetermined pulling axis, as in the case of the combination having high wettability described above. That is, the hook-shaped member shown in the above-described embodiment, the region with different wettability, and the like serve as a behavior suppressing member for suppressing the diameter expansion behavior of the raw material melt in a plane perpendicular to a predetermined pulling axis. Is included. It should be noted that the saddle-like member is the same in the case of any combination in that it is arranged so as to wind the opening at the end where the hole opens, and only differs at the embedded end. Further, in any combination of shapes, the so-called triangular shape in which the protruding tip is the top in a cross section in a plane including the axis of the hook-shaped member in the protruding direction and the predetermined pulling axis. It is preferable that If it is the said shape, the effect which prevents this will be acquired about any of transmission of a melt, or addition of the repulsive force with respect to a melt in the top part of a bowl-shaped member. Further, when materials having different wettability are arranged, for example, when the wettability is large and the contact angle is 90 ° or more, the wettability contrary to the wettability is small and the contact angle is less than 90 °. It is preferable to use a material.

  Here, when it is going to obtain a fiber-like single crystal using the raw material melt 9 with low wettability with respect to the crucible 11, the raw material melt 9 is in a state of being repelled by the inner wall surface of the crucible. For this reason, when this wettability is particularly small, it is assumed that the raw material melt 9 does not enter the hole portion 11a as shown in FIG. In such a case, the seed holder holding the seed at its tip is inserted into the hole 11a until it contacts the raw material melt 9, and then the seed is lowered to lower the raw material melt 9 combined with the seed. It is considered that crystal growth can be carried out by pulling out from the hole 11a to the external space. However, the presence or absence of contact between the seed and the raw material melt 9 or the suitability of the contact state is an event in the space covered by the crucible 11, and thus it is difficult to confirm this directly. . For this reason, after the contact operation, the seed is once pulled down to the outside of the hole portion 11a, and after confirming the presence or absence of this contact, etc., a specific pulling operation can be considered. However, such a process requires the visual observation of the operator, and it is necessary to take into consideration that redoing is performed. Such a process may be a big problem in automating the growth of a fiber-like single crystal. Further, as described above, in the case where the solid-liquid boundary region 9b is formed in the cylindrical portion 11b, visual confirmation of this portion is virtually impossible.

  Therefore, in the present embodiment, the conditions for starting the pulling-down operation when using a raw material melt that has a low wettability with respect to the crucible and is particularly difficult to flow out to the outside due to an action such as gravity are defined as follows. A specific method of determining conditions will be described with reference to FIG. 7 and FIGS. 8A and 8B described later show the related configuration in the same manner as FIG. 1 and the like. Normally, even if the raw material melt has low wettability with respect to the crucible 11, for example, in the case of a crucible having a flat lower end surface, the raw material melt forms a lower liquid surface following the lower end surface due to the influence of gravity. It is assumed. However, when the lower end surface has a conical shape projecting downward and communicates with the hole 11a described above at the top of the conical shape, the lower liquid surface does not reach the top of the conical shape. Can be considered.

  For this reason, when performing the so-called seed touch operation in which the seed 7 is inserted into the crucible 11 by the seed holder 8 through the hole 11a and the seed 7 is brought into contact with the raw material melt 9, the cylindrical portion of the crucible 11 It is preferable to insert the seed 7 to the lower surface. That is, ideally, it is necessary to secure the upward movement width of the seed holder 8 by a distance d2 from the opening of the crucible 11 to the lower end of the cylindrical portion. Although it depends on the wettability value and the specific gravity of the raw material melt 9, it is usually assumed that the lower surface of the raw material melt 9 has reached the vicinity of the top of the conical shape. Further, when the seed 7 is inserted into the raw material melt 9 more than necessary, abnormal crystal growth may occur due to the contact between the seed holder 8 and the raw material melt 9 at the initial stage of pulling down. Therefore, normally, the distance d2 described above is replaced with the distance d1 from the opening of the crucible 11 to the opening inside the crucible 11 of the hole 11a, and the distance seed holder 8 is moved to perform the seed touch described above. It is considered preferable. That is, the upper end of the moving width of the sheet holder 8 is set in the space inside the crucible, and more specifically, it is preferably set at a position that satisfies the above-described distance d1 or more.

  In addition, when performing the seed touch based on the distance d1, in the case of a combination of a raw material melt having extremely low wettability and a crucible, there is a possibility that the contact of the seed becomes inappropriate. In such a case, the seed may be brought into contact with the raw material in a stage before melting the raw material, and the raw material may be melted from the state. The procedure is schematically shown in FIGS. 8A and 8B. In FIG. 8A, a raw material 9 ′ before melting is accommodated in the crucible 11. The seed 7 is held at a position in contact with the raw material 9 ′ in the crucible 11 by a seed holder 8 that can expand and contract in the pulling-down direction. From this state, the raw material 9 'is melted. The seed 7 and the raw material melt 9 are essentially the same material and have a very high wettability. Therefore, by this melting operation, the raw material melt 9 is surely formed in contact with the seed 7. By pulling down the seed holder 8 as shown in FIG. 8B from this state, formation of the seed touch and the solid-liquid boundary region 9b in the cylindrical portion 11b is achieved, and stable fiber-like single crystal is grown. It becomes possible to do. Note that since the raw material 9 ′ and the seed 7 are each solid, there is a possibility that the positions of the raw material 9 ′ and the contact state cannot be obtained at the initial melting stage of the raw material 9 ′. As a countermeasure for such a case, the seed 7 may be bonded and fixed to the raw material 9 ′ with an adhesive or the like, for example. Moreover, it is preferable that the insertion depth (entry depth from the opening) d3 into which the seed holder 8 is inserted into the crucible 11 in advance is d1 ≦ d3 <d2 with respect to d1 and d2. By satisfying the condition, both can be stably melted. For example, if a known epoxy type adhesive is used, the adhesive burns and dissipates due to heating when the raw material is melted. Therefore, the influence of the adhesive on the fiber-like single crystal is substantially reduced. Is not considered to exist.

  Further, as another form of so-called seed touch in which the seed and the raw material melt are brought into contact with each other, the seed is melted in advance similarly to the raw material, and the seed in the molten state is inserted into the crucible 11. good. In this case, the insertion depth may be determined in advance as d3, and the insertion may be performed after the seed 7 is melted. When the seed 7 in the molten state is brought close to the raw material melt, both melts are attracted and stabilized by the surface tension between the melts, even if the approach is insufficient and contact is not possible in terms of distance. Seed touch can be performed. In particular, in the case of the crucible in which the above-described rod-shaped member is disposed, unless the position of the seed touch is strictly controlled by the influence of the temperature gradient in the rod-shaped member, the crystal and the raw material melt It is difficult to stably maintain the solid-liquid interface. By ensuring that the seed touch is stably performed as described above, it is possible to stably grow the fiber-like single crystal from the initial stage of growth regardless of the presence of the hook-shaped member. That is, by using the crucible structure described in the second embodiment, it is possible to obtain a high-quality fiber single crystal having an excellent surface state. Further, by adding to the crucible structure and making the operation range of the seed holder 8 at the time of seed touch into a range that takes into account the distance d1 or d2, the fiber-like single crystal can be stably obtained. . Further, by fixing the seed 7 in contact with the raw material 9 'in advance and melting them together, a high-quality fiber single crystal can be obtained with higher reproducibility.

  In the above-described embodiment, the crucible shape or the crucible opening when the shape of the single crystal to be obtained is a columnar shape or a prism shape is described. However, according to the present invention exemplified in the first and second embodiments described above, a fiber-like single crystal having a desired outer shape can be obtained. 9A to 9E illustrate the shape of the opening of the crucible 11 when obtaining single crystals of various desired shapes. 9A is a triangular prism, FIG. 9B is a pentagonal prism, FIG. 9C is a hexagonal prism, FIG. 9D is a substantially U-shaped cross section, FIG. 9E is a cross-shaped cross section, and FIG. 9F is a rectangular section with rounded corners. The opening shape which is going to obtain each single crystal of a shape is shown. In addition, the present invention is not limited to the configuration in which one single crystal is obtained for one crucible. As shown in FIGS. 10A to 10C as a view of the lower surface of the crucible including the opening, a plurality of fiber-like single crystals may be grown simultaneously. 10A is a crucible form for growing two single crystals, FIG. 10B is a crucible form for growing three single crystals, and FIG. 10C is for growing four single crystals. Each of the forms of the crucible is shown. The fiber-like single crystal has a predetermined crystal orientation in a plane perpendicular to the pulling direction. This crystal orientation is always required to be clear in relation to the post-process. In the present invention, processed portions such as notches and notches corresponding to the crystal orientation of the fiber-like single crystal are formed on the flange portion 11d or the second flange portion 11f. According to the present invention, the outer diameter of the fiber-shaped single crystal according to the flange 11d or the like can be obtained according to the outer shape defined by the flange 11d. Therefore, the notch or the like forms a clear mark that defines the directionality with respect to the outer shape of the fiber-like single crystal.

  Next, the single crystal pulling apparatus having the crucible shown in the embodiment described above will be described. FIG. 11 shows a cross-sectional configuration of the main part of the pulling device and along the crystal pulling direction of the device. The pulling device 1 mainly includes a crucible 11, an after heater 13, a heating tube 15, a work coil 17, a tube stage 19, a crucible stage 21, an inner tube 23, an outer tube 25, a first vertical adjustment mechanism 27, and A second vertical adjustment mechanism 29 is provided. The pulling device 1 heats and melts the material by high frequency induction. The high frequency is transmitted to a heating source or the like via a work coil 17 in which a metal tube capable of conducting cooling water or the like is formed in a coil shape having a predetermined inner diameter. The crucible 11 in which the raw material is held and melted has a cylindrical shape with the bottom surface (lower end surface) closed, and is made of carbon or a refractory metal (for example, Re, Ir, W, Ta, Mo, Pt, or These alloys). Since the specific shape of the crucible 11 has already been described in detail, the description thereof is omitted here. The crucible 11 is coaxial with the work coil 17 and is disposed at a central portion in the longitudinal direction of the work coil 17.

  In the present embodiment, the lower end surface is formed in a conical shape in which the central portion where the pores are provided is most convex so that the raw material inside the crucible 11 can be used efficiently. Further, the crystal pulling direction coincides with the axial direction of the crucible 11 and the like described later. Below the crucible 11, a cylindrical after-heater 13 that contacts the lower end of the crucible 11 and supports the crucible 11 is disposed. The after heater 13 is made of the same material as that of the crucible and is arranged so as to be coaxial with the crucible 11. When the raw material is heated, the after-heater 13 also generates heat by high frequency induction, and the raw material leaking from the lower end of the crucible 11 can be heated. Further, the length of the after heater 13 is such that when the crucible 11 disposed in the central portion in the longitudinal direction of the work coil 17 and the after heater 13 are disposed in contact with each other, the effective heating area in the work coil 17 is reduced. The after heater 13 is set to be accommodated. By installing the after heater 13, the soaking area in the pulling-down direction can be expanded, and the conditions for crystal growth can be made wider. In the present embodiment, the after heater 13 is supported at the lower end thereof by the upper surface of the annular crucible stage 21. The crucible stage 21 is made of a material having insulating properties against high frequencies used for heating, such as ceramics and quartz.

  The crucible stage 21 is supported on the lower surface by an upper end portion of a cylindrical inner tube 23 made of the same material as the stage 21. The crucible 11, the after heater 13, the crucible stage 21 and the inner tube 23 are arranged so as to be coaxial, and the crystal pulling operation is performed along the axis. The lower end portion of the inner tube 23 is connected to a second vertical adjustment mechanism 29, and can be moved up and down in the axial direction by the adjustment mechanism 29. In this apparatus, a heating tube 15 exists as a main configuration that generates heat by high frequency. The heating tube 15 has a cylindrical shape having an inner diameter larger than the outer diameter of the crucible 11 and an outer diameter smaller than the inner diameter of the work coil 17, and is made of carbon or high melting point metal (for example, Re, Ir, W, Ta, Mo, Pt, or alloys thereof. The heating tube 15 is disposed so as to be concentric with the crucible 11 so that the crucible 11 is accommodated on the inner side and the work coil 17 is present on the outer peripheral side. The length of the heating tube 15 is set such that the tube 15 slightly protrudes from the effective heating region in the longitudinal direction of the work coil 17.

  The heating tube 15 is in contact with the upper surface of the annular tube stage 19 at the lower end and is supported by the tube stage 19. The annular inner diameter of the tube stage 19 is set to be larger than the outer diameter of the crucible stage 21, and these stages are prevented from interfering with each other when moving independently in the axial direction. The tube stage 19 is made of a material having insulating properties against high frequencies used for heating, such as ceramics and quartz. The tube stage 19 is supported on the lower surface by an upper end portion of a cylindrical outer tube 25 made of the same material as the stage 19. The heating tube 15, the tube stage 19, and the outer tube 25 are arranged so as to be coaxial with the crucible 11 and the like, and accommodate the crucible 11, the after heater 13, the crucible stage 21, and the inner heater 23 on the inner side. Yes. The lower end portion of the outer tube 25 is connected to a first vertical adjustment mechanism 27, and can be moved up and down in the axial direction by the adjustment mechanism 27.

  There is also a high frequency transmitted to the crucible 11 and the after heater 13 through the heating tube 15, and in this configuration, the crucible 11 and the after heater 13 themselves also generate heat. By suitably correlating these heat sources and the soaking area obtained by the heating tube 15, it is possible to obtain a wide soaking area in a plane that is long in the pulling direction and perpendicular to the pulling direction. In addition, the high frequency radiated from the work coil 17 can be efficiently converted into heat, and the raw material can be heated to a higher temperature. In this apparatus, the heating tube 15 and the structure composed of the crucible 11 and the after-heater 13 are each independently movable in the pull-down axis direction. Considering the conditions for crystal growth, for example, it may be necessary to appropriately change the length of the soaking area formed in the pulling direction from the hole of the crucible 11. In this apparatus, by driving at least one of the first vertical adjustment mechanism 27 and the second vertical adjustment mechanism 29, the length of the soaking area, more precisely, the crystal growth site with respect to the soaking area is set. The arrangement can be easily and quickly changed.

  In the embodiment described above, a jig for holding the seed, a structure for moving the jig up and down along the pulling direction, a structure for observing the solid-liquid boundary surface of the raw material melt leaking from the crucible hole, etc. Is omitted. However, in the above-described embodiment, these components are simply omitted for ease of explanation, and these components are actually arranged. In addition, depending on the crystal to be obtained, it may be necessary to reduce the oxygen partial pressure in the atmosphere, or to create an atmosphere environment made of a specific gas. It is preferable to arrange | position in the inside of the airtight space in which etc. are possible. Further, in the present embodiment, each configuration is formed of a cylindrical shape or an annular shape, but the present invention is not limited to these shapes, and as described above, the shape of the cross section (end face) perpendicular to the pulling direction is used. Various modifications can be made according to the outer shape of the fiber-like single crystal to be obtained. In this case, when the respective components are arranged so as to be all concentric with respect to a predetermined axis parallel to the pulling-down direction, the interval formed between the respective components may be kept substantially constant. Moreover, although the inner tube and the outer tube are assumed to be cylindrical members, these may be simply rod-shaped members, and the crucible stage and the tube stage may be supported by these rod-shaped members.

  In addition, although the heating tube is used only as a single unit, a plurality of tubes having different inner and outer diameters may be stacked in a nested manner, and these may be used as a single unit. In this case, the length of each tube may be varied to change the soaking area. In this case, it is good also as a structure which prepares several tubes with the same diameter and short length with respect to a work coil, and arranges these at intervals in the longitudinal direction of a work coil. Alternatively, the heat retaining tube disposed outside the heating tube may be composed of a plurality of tubes, and the same deformation as the above-described heating tube may be performed. By modifying these tube configurations, it is also possible to selectively promote various effects such as expansion of the soaking area, improvement of heating efficiency, and heating of a specific part at a high temperature. Moreover, it is good also as eliminating the after heater and making the heating tube carry out the function of the after heater.

  In the present embodiment, the first and second vertical adjustment mechanisms are used. However, the present invention is not limited to this form. Specifically, it is possible to obtain the adjustment effect of the soaking area by arranging only one of the adjustment mechanisms. Further, in a further embodiment, the heat retaining tube is supported by the same tube stage as the heating tube, but this may be supported by each independent stage so that each stage can be adjusted up and down independently. . Further, the lengths of the heat retaining tube and the heating tube are made substantially the same, and the length of the work coil is set slightly smaller than these lengths, but these lengths may be appropriately modified. For example, the length of the work coil may be extended downward from the illustrated shape, and the length of the heating tube may be extended further downward. Thereby, it becomes possible to make the heating tube act as an after heater, and the after heater can be removed. In the present invention, the crucible 11 is a high melting point material that is resistant to the temperature at which the raw material housed therein is melted, and has such a high frequency that can be generated by the high frequency emitted from the work coil 17. It needs to be made of a material that can conduct electricity. Therefore, although it is preferable to be composed of a refractory metal as described above, for example, it may be formed by adding a material capable of conducting high frequency on the ceramic surface or inside, forming a layer, or the like. Therefore, the crucible is preferably defined as being composed of a high melting point material capable of conducting high frequency. For the same reason, it is preferable that the heating tube 15 and the after-heater 13 are also defined as being composed of a high melting point material capable of conducting high frequency.

  Further, as described above, since each configuration does not need to be a cylinder, each configuration is preferably defined as a cylindrical shape. In addition, when the shape is not a cylinder, it is preferable to geometrically match the predetermined axis that is the crystal pulling direction and the central axis of each configuration, but each actual configuration can obtain a clear central axis. It may be difficult, and it is preferable that the axis of each component to be matched with the central axis is grasped as a substantially central axis. Further, the after heater needs to have a peep hole or the like for observing the solid-liquid interface in crystal growth, and there is a possibility that it differs from a cylinder shape in an accurate sense depending on the formation conditions of the peep hole. Therefore, the shape of the after heater is preferably grasped as a substantially cylindrical shape. The first vertical adjustment mechanism and the second vertical adjustment mechanism only have to be able to move the crucible stage and the tube stage relative to each other in a predetermined axial direction. Therefore, it is preferable that these configurations are grasped as an adjustment mechanism that relatively moves the crucible stage and the tube stage as a unit.

  Next, a lowering device embodying the present invention will be described with reference to the drawings. In addition, about the structure which exhibits the same effect as the structure described in previous embodiment and an apparatus structural example, the same referential mark is used and this shall be abbreviate | omitted for detailed description. FIG. 12 is a front view including a partial cross-sectional view illustrating a configuration when the pulling device according to the present embodiment is viewed from the front. Similar to the apparatus configuration example described above, the pulling apparatus 1 has the work coil 17, the heating tube 15, the crucible 11, the after heater 13, the tube stage 19, the crucible stage 21, the outer tube 25, and the like, with the crystal pulling axis as the axis. An inner tube 23 is provided. The outer tube 25 and the inner tube 23 are supported by an outer tube support base 35 and an inner tube support base 37, respectively. These configurations are all arranged inside the vacuum chamber 43. Further, below the crucible 11 in the axial direction, a seed holder 39 that can be driven on the same axis and a lowering mechanism (not shown) that supports the seed holder 39 in a drivable manner are arranged.

  The vacuum chamber 43 is composed of a substantially columnar chamber whose upper and lower surfaces each have a shape obtained by cutting an ellipse in the minor axis direction, and the side surface that is a plane is an opening surface 43a. A door (not shown) is attached to the opening surface 43a so as to be openable and closable, and a seal member (not shown) disposed in a contact portion between the outer peripheral portion of the opening surface 43a and the door (not shown) Airtightness is maintained. The vacuum chamber 43 is connected to the upper surface of a small-diameter bellows 43b that extends substantially in the vertical direction on the bottom surface. In addition, the bellows 43b is closely fixed to the surface of an XY table (not shown) at the lower end, and a vacuum space is formed by the vacuum chamber 43, the door, the bellows 43b, and the upper surface of the XY table. The vacuum space is connected to an exhaust system 15 (not shown), and the interior of the space is exhausted by the exhaust system, and decompression and pressure control of the space are performed.

  The seed holder 39 is disposed so as to penetrate the inside of the bellows 43b, and a lower end portion thereof is fixed to the upper surface of the XY table. The XY table drives the seed holder 39 in the X and Y biaxial directions orthogonal to each other in the horizontal plane. The XY table is supported by a pulling mechanism so as to be vertically movable, and the seed holder 39 is driven vertically downward at a predetermined speed. The work coil 17 is connected to a high-frequency oscillation device (not shown) outside the vacuum chamber and a vertical adjustment mechanism 45 for the work coil via an introduction hole 43c provided in the vacuum chamber 43 in which a seal member (not shown) is inserted. ing. The vertical adjustment mechanism 45 drives the work coil 17 in the axial direction, adjusts the positional relationship between the work coil 17 and the crucible 11 and adjusts the arrangement of the work coil 17 in the vacuum chamber 43. The work coil up-and-down adjustment mechanism 45 includes a known motor, a ball screw, a ball screw shaft, a linear guide, and the like. However, since the driving device is not the main configuration of the present invention, a description thereof is omitted here. To do.

  The vacuum chamber 43 further includes a viewing window (not shown) that enables observation of the solid-liquid interface between the molten material and the crystal formed below the crucible 5 from different directions. It is preferable that an imaging device in which the imaging optical axis reaches the substantially central portion of the solid-liquid boundary surface through the observation window is disposed outside the observation window. The solid-liquid boundary surface exists in a region surrounded by the work coil 17, the heating tube 15, and the after heater 13. For this reason, the heating tube 17 and the after heater 13 are provided with through holes (not shown) on the side surfaces so that the solid-liquid boundary surface can be observed from the observation window. The outer tube support base 35 is connected to the first vertical adjustment mechanism 27 disposed outside the vacuum chamber through a second introduction hole 43d provided in the vacuum chamber 43 in which a seal member (not shown) is inserted. Has been. As described above, the vertical adjustment mechanism 27 drives the heating tube 15 in the axial direction to adjust the positional relationship between the work coil 17 and the heating tube 15 and the positional relationship between the heating tube 15 and the crucible 11. The first vertical adjustment mechanism 27 includes a known motor, a ball screw, a ball screw shaft, a linear guide, and the like. However, since the driving device is not the main configuration of the present invention, description thereof is omitted here. To do.

  The inner tube support 37 is connected to a second vertical adjustment mechanism 29 disposed outside the vacuum chamber through a third introduction hole 43e provided in the vacuum chamber 43 in which a seal member (not shown) is inserted. Has been. As described above, the vertical adjustment mechanism 29 drives the crucible 11 and the after-heater 13 in the axial direction to adjust the positional relationship between the work coil 17 and the crucible 11 and the positional relationship between the heating tube 15 and the crucible 11. Do. The second vertical adjustment mechanism 29 includes a known motor, a ball screw, a ball screw shaft, a linear guide, and the like. However, since the driving device is not the main configuration of the present invention, description thereof is omitted here. To do. A gas supply system (not shown) is connected to the vacuum chamber 43, and the atmosphere gas required during crystal growth can be introduced into the vacuum space via the gas supply type. Moreover, the pressure at the time of crystal growth is controlled by controlling the opening degree of any of the above-described valves and the gas supply amount. The vacuum chamber 43 is connected to an unillustrated evacuation system, but the evacuation system can be changed as appropriate according to the pulling speed, operating pressure, ultimate vacuum, etc. required for actual crystal growth. Is desirable. Further, the shape of the vacuum chamber 43 is such that the side surface is most releasable from the viewpoint of securing a work space for exchanging and maintaining crucibles, seed crystals, refractories, etc. The shape of the vacuum chamber is not limited to this, and it is desirable to change appropriately from the viewpoints of heating conditions, workability, productivity, and the like.

  The fiber single crystal pulling apparatus described above makes it possible to easily and reliably obtain a fiber single crystal having a smooth surface state and a desired shape. More specifically, according to the pulling-down device according to the present invention, the surface tension of the raw material melt, or the wettability of the surface material such as a crucible in contact with the raw material melt at or around the hole and the previous material melt, It is possible to suppress the uneasy behavior of the raw material melt caused by. Therefore, it is possible to suppress the shape abnormality of the surface of the fiber-like single crystal due to such an uneasy behavior, and to process into a desired shape that does not require post-processing.

  The present invention provides high quality, such as silicon, lithium niobate (LN), lithium tantalate (LT), yttrium-aluminum garnet (YAG), sapphire, eutectic, scintillation crystal, terphenol D, etc. It is applicable when manufacturing a fiber-like single crystal material. More specifically, fibers that were difficult to manufacture by the FZ method, Bridgman method, CZ method, etc., as functional materials used in the field of electronics or optoelectronics, or as structural materials used in high-temperature environments, etc. It can be used as an apparatus for producing a crystal whose shape is controlled to a shape, columnar shape, prismatic shape, plate shape, tube shape or the like.

It is a figure which shows typically the lower end part of the crucible which is a conventional structure, and a part of single crystal pulled down from this crucible. It is a figure which shows the principal part of the structure of the crucible used for the pulling-down apparatus based on one Embodiment of this invention in the style similar to FIG. It is a figure which shows the modification of embodiment shown to FIG. 2A. It is a figure which shows the other modification of embodiment shown to FIG. 2A. In the embodiment shown in FIG. 2B, it is a figure which shows the 1st modification | change mode of the crucible potion according to the property of raw material melt. In the embodiment shown in FIG. 2B, it is a figure which shows the 2nd modification | change mode of a crucible collar part according to the property of raw material melt. In the embodiment shown in FIG. 2B, it is a figure which shows the 3rd modification | change mode of a crucible collar part according to the property of raw material melt. In the embodiment shown in FIG. 2B, it is a figure which shows the 4th modification | change mode of a crucible collar part according to the property of raw material melt. It is a figure which shows typically the lower end part of the crucible which is a conventional structure, and a part of single crystal pulled down from this crucible. It is a figure which shows the principal part of the structure of the crucible used for the pulling-down apparatus based on 2nd embodiment of this invention in the style similar to FIG. It is a figure which shows the modification of embodiment shown to FIG. 5A. It is a figure which shows the other modification of embodiment shown to FIG. 5A. It is a figure which shows typically the state assumed when the wettability with a crucible and a raw material melt is bad in embodiment shown in FIG. It is a figure explaining the coping method with respect to appearance of the state shown in FIG. It is a figure which shows one of the procedure about the coping method with respect to appearance of the state shown in FIG. It is a figure which shows the 2nd procedure about the coping method with respect to appearance of the state shown in FIG. It is a figure which shows typically the shape of the crucible opening for obtaining the fiber-shaped single crystal of a cross-sectional triangle. It is a figure which shows typically the shape of the crucible opening for obtaining the fiber-shaped single crystal of a cross-sectional pentagon. It is a figure which shows typically the shape of the crucible opening for obtaining the fiber-shaped single crystal of a cross-sectional hexagon. It is a figure which shows typically the shape of the crucible opening for obtaining the fiber-shaped single crystal of a U-shaped cross section. It is a figure which shows typically the shape of the crucible opening for obtaining the cross-sectional fiber-shaped single crystal. It is a figure which shows typically the shape of the crucible opening for obtaining the rectangular fiber-shaped single crystal which the cross section rounded the corner | angular part. It is a figure which shows the crucible structure for obtaining two fiber-like single crystals by single operation in the style seen from the lower end part side. It is a figure which shows the crucible structure for obtaining three fiber-like single crystals by single operation in the style seen from the lower end part side. It is a figure which shows the crucible structure for obtaining four fiber-like single crystals by single operation in the style seen from the lower end part side. It is a figure which shows schematic structure in the state which looked at the main structure of this apparatus from the side surface about the pulling-down apparatus which mounts the crucible based on embodiment of this invention. It is a side view which shows the principal part structure of this apparatus about the specific structure of the pulling-down apparatus which concerns on this invention.

Explanation of symbols

1: Pulling device, 7: Seed, 8: Seed holder, 9: Raw material melt, 11: Crucible, 13: After heater, 15: Heated tube, 17: Work coil, 19: Tube stage, 21: Crucible stage, 23 : Inner tube, 25: Outer tube, 27: First vertical adjustment mechanism, 29: Second vertical adjustment mechanism, 31: Thermal insulation tube, 35: Outer tube support base, 37: Inner tube support base, 39: Seed retention Tools, 43: vacuum chamber, 45: vertical adjustment mechanism for work coil

Claims (8)

A crucible made of a high melting point material capable of conducting high frequency, having a hole at the bottom that can hold the raw material melt inside and can draw out the raw material melt from the inside;
A heating coil that is wound around the crucible and radiates the high frequency to the crucible;
Holding a seed that defines a crystal orientation when the raw material melt is crystallized, and a seed holder that pulls down the seed along a predetermined pulling axis passing through the hole of the crucible,
Around the hole in the opening of the hole, a behavior of suppressing a diameter expansion behavior in a plane perpendicular to the predetermined pulling axis of the raw material melt when the raw material melt is drawn out from the hole A restraining member is arranged ,
The behavior suppressing member is configured by enlarging an outer shape of an opening end surface, which is a plane in which the hole in the crucible opens, from the outer shape of the cylindrical portion in which the hole of the crucible is formed, and winds the opening. flanged member der Rukoto projecting the outer direction from the cylindrical portion, pull down device to obtain a fibrous crystals from said raw material melt, characterized in. The pulling device according to claim 1 , wherein the bowl-shaped member is made of the same material as the crucible and is formed as a part of the crucible. The saddle-shaped member has a maximum outer shape at the opening end surface so that the outer shape of the opening end surface decreases as the distance from the opening end surface along the pulling shaft decreases. in cross-section in a plane containing, reductions apparatus according to claim 1 or 2 wherein the tip portion protruding is characterized to be a triangular shape as a top. The behavior suppression member is pulled apparatus according to any one of claims 1 to 3, characterized in that it has an orientation flat forming portion for forming a possible specific orientation flat crystal orientation in the fibrous crystals. The raw material melt that is made of a high melting point material that can conduct high frequency, has a hole in the bottom portion that can hold the raw material melt and can draw the raw material melt from the inside, and leaks from the hole. On the other hand, when making a fiber-shaped single crystal from the raw material melt by bringing a seed that determines a crystal orientation when the raw material melt is crystallized into contact with each other and pulling down the seed along a predetermined pulling axis. A crucible used,
Around the hole in the opening of the hole, a behavior of suppressing a diameter expansion behavior in a plane perpendicular to the predetermined pulling axis of the raw material melt when the raw material melt is drawn out from the hole A restraining member is arranged ,
The behavior suppressing member is configured by enlarging an outer shape of an opening end surface, which is a plane in which the hole in the crucible opens, from the outer shape of the cylindrical portion in which the hole of the crucible is formed, and winds the opening. crucible, wherein the flanged member der Rukoto, protruding in the outer direction from the cylindrical portion. The crucible according to claim 5 , wherein the crucible member is made of the same material as the crucible and is formed as a part of the crucible. The saddle-shaped member has a maximum outer shape at the opening end surface so that the outer shape of the opening end surface decreases as the distance from the opening end surface along the pulling shaft decreases. The crucible according to claim 5 or 6 , wherein in a cross section in a plane including the shape, the protruding tip portion has a triangular shape having a top portion. The crucible according to any one of claims 5 to 7 , wherein the behavior suppressing member has an orientation flat forming portion that forms an orientation flat capable of specifying a crystal orientation in the fiber crystal.

Images