JP2020152616A - Seed crystal used for single crystal growth, installation method of seed crystal, and crucible for single crystal growth - Google Patents

Abstract

To provide a seed crystal capable of easily growing a prism-shape single crystal having a side surface of a specific crystal orientation in a growth of an iron gallium alloy single crystal by a VB method and a VGF method, an installation method of the seed crystal, and a crucible for single crystal growth.SOLUTION: A seed crystal is for growing a single crystal by a VB method or a VGF method, the seed crystal being pillar shape. A top surface of the seed crystal is an inclined plane, the inclined plane inclining to a specific crystal orientation.SELECTED DRAWING: Figure 3

Description

The present invention relates to a seed crystal used for growing a single crystal, a method for setting the seed crystal, and a crucible for growing a single crystal (hereinafter, also referred to as "crucible").

In recent years, with the development of IoT (Internet of Things), vibration power generation, which is a method of energy harvesting technology, has attracted attention as a power source for small electronic devices.

Vibration power generation is a power generation method that converts mechanical energy existing in the environment into electric power and uses it. Piezoelectric type, movable magnet type, electrostatic type and the like have been proposed as a method of vibration power generation, but Patent Document 1 shows a vibration power generation method using a magnetic strain material as a high-efficiency and low-cost power generation method.

As the magnetostrictive material, an iron-gallium alloy having high magnetostrictive characteristics, which is relatively inexpensive and can be machined, is regarded as promising. Then, from the viewpoint of increasing the azimuth integration degree in the <100> direction, which is the direction in which magnetization is easy, development of a manufacturing technique for an iron-gall alloy single crystal is required.

As a single crystal growth method, a pulling method (Czochralski method) is shown in Patent Document 2. However, since the single crystal grows in a columnar shape, there is a problem that the number of man-hours increases when the single crystal is processed into a plate shape and a processing loss of the single crystal alloy occurs.

On the other hand, a vertical bridgeman method (hereinafter, also referred to as "VB method") and a vertical temperature gradient solidification method (hereinafter, also referred to as "VGF method") are performed using a prismatic pit and a seed crystal, and a crystal having a specific side surface is performed. Patent Document 3 shows a method for growing a prismatic single crystal having an orientation.

Japanese Unexamined Patent Publication No. 2014-18006 Japanese Unexamined Patent Publication No. 2016-28831 Japanese Unexamined Patent Publication No. 2014-76915

However, in the method described in Patent Document 3, when the crucible is formed into a prismatic shape, it is necessary to process it with high accuracy so that the side surface of the fixed diameter portion of the crucible and the side surface of the small diameter portion on which the seed crystal is placed are in the same direction. was there. Further, since it is necessary to install the seed crystal so that the side surface of the constant diameter portion of the crucible and the side surface of the seed crystal are parallel to each other, high accuracy is required for the installation of the seed crystal.

In view of these circumstances, the present invention is a seed capable of easily growing a prismatic single crystal having a specific crystal orientation on the side surface in growing an iron-gallium alloy single crystal by the VB method or the VGF method. It is an object of the present invention to provide a method for installing crystals and seed crystals, and a single crystal growing pit.

One aspect of the present invention is a seed crystal for growing a single crystal by the VB method or the VGF method, the seed crystal has a cylindrical shape, the upper surface of the seed crystal is an inclined surface, and the inclined surface is an inclined surface. It is characterized by inclining to a specific crystal orientation.

When growing a single crystal by the VB method or the VGF method, the seed crystal can be placed in the pit so that the direction of the inclined surface of the seed crystal and the predetermined direction of the constant diameter portion of the pit coincide with each other. The side surface direction of the single crystal of the shape can be set to a specific crystal orientation, and the labor of crystal orientation in the plate-shaped member cutting process and the weight loss due to the process can be reduced.

At this time, the seed crystal may be a single crystal of an iron-gallium alloy.

Since the iron-gallium alloy has a body-centered cubic structure, it is possible to grow a prismatic single crystal whose upper and lower surfaces and all side surfaces are (100) surfaces.

At this time, the crystal orientation may be the <100> direction perpendicular to the growth direction of the single crystal.

In this way, it is possible to grow a prismatic single crystal in which the upper and lower surfaces and all the side surfaces are (100) surfaces.

One aspect of the present invention is a method for setting a seed crystal for growing a single crystal using a pit by the VB method or the VGF method, wherein the cross section of the fixed diameter portion of the pit is square, and the seed crystal is It has a cylindrical shape, the upper surface of the seed crystal is an inclined surface, the inclined surface is inclined in a specific crystal orientation, the seed crystal is placed in a small diameter portion of the pit, and the seed crystal is reflected from the upper surface of the seed crystal. It is characterized in that the seed crystal is placed so that the predetermined direction of the constant diameter portion of the pit and the crystal orientation coincide with each other by using the reflection position of the light beam.

When growing a single crystal by the VB method or the VGF method, the seed crystal can be placed in the pit so that the crystal orientation of the inclined surface of the seed crystal and the predetermined direction of the prismatic pit are aligned with each other. The side surface direction of the single crystal can be set to a specific crystal orientation. Then, it is possible to reduce the labor of crystal orientation in the plate-shaped member cutting process and the weight loss due to the process.

At this time, the seed crystal may be a single crystal of an iron-gallium alloy.

Since the iron-gallium alloy has a body-centered cubic structure, it is possible to grow a prismatic single crystal whose upper and lower surfaces and all side surfaces are (100) surfaces.

At this time, the small-diameter portion in which the seed crystal of the crucible is placed may have a cylindrical well shape.

Since the cylindrical seed crystal can be easily rotated about the vertical direction, the crystal orientation of the inclined surface of the seed crystal and the predetermined direction of the prismatic crucible can be easily matched.

At this time, the crystal orientation is the <100> direction perpendicular to the growth direction of the single crystal, and the deviation between the predetermined direction of the constant diameter portion of the crucible and the crystal orientation may be within 1 °.

In this way, when processing a prismatic single crystal into a plate-shaped member, it is possible to reduce the labor of crystal orientation in the cutting process and the weight loss due to the processing.

One aspect of the present invention is a crucible for growing a single crystal by the VB method or the VGF method, the cross section of the fixed diameter portion of the crucible is square, and the small diameter portion on which the seed crystal of the crucible is placed. The cross section is characterized by being circular.

When growing a single crystal by the VB method or the VGF method, the seed crystal can be placed in the pit so that the crystal orientation of the inclined surface of the seed crystal and the predetermined direction of the prismatic pit are aligned with each other. The side surface direction of the single crystal can be set to a specific crystal orientation. Then, it is possible to reduce the labor of crystal orientation in the plate-shaped member cutting process and the weight loss due to the process.

At this time, the seed crystal may be a single crystal of an iron-gallium alloy.

Since the iron-gallium alloy has a body-centered cubic structure, it is possible to grow a prismatic single crystal whose upper and lower surfaces and all side surfaces are (100) surfaces.

According to the present invention, when a single crystal is grown by the VB method or the VGF method, the seed crystal can be placed in the pit so that the crystal orientation of the inclined surface of the seed crystal and the predetermined direction of the prismatic pit coincide with each other. Therefore, the side surface direction of the prismatic single crystal can be set to a specific crystal orientation. Then, it is possible to reduce the labor of crystal orientation in the plate-shaped member cutting process and the weight loss due to the process.

FIG. 1 is a schematic cross-sectional view of a single crystal growing device for growing an iron-gall alloy single crystal ingot according to an embodiment of the present invention. FIG. 2 is a perspective view showing an example of the shape of a crucible in which a seed crystal according to an embodiment of the present invention is installed. FIG. 3 is a perspective view showing a shape example of a seed crystal according to an embodiment of the present invention. FIG. 4 is a schematic perspective view showing the crystal orientation of the inclined surface of the seed crystal and the light reflection on the upper surface of the seed crystal according to the embodiment of the present invention. FIG. 5 is a schematic perspective view illustrating a method of installing a seed crystal according to an embodiment of the present invention.

Hereinafter, a seed crystal of an iron-gall alloy, a method for installing the seed crystal, and a crucible for growing a single crystal according to an embodiment of the present invention will be described. The present invention is not limited to the following examples, and can be arbitrarily modified without departing from the gist of the present invention.

Iron-gallium alloys are attracting attention as magnetostrictive materials used for magnetostrictive vibration power generation because they have high magnetostrictive characteristics, the material is relatively inexpensive, the tensile strength is about the same as iron, and they are hard to crack and easy to process. Further, the plate-shaped member used for the magnetostrictive vibration power generation has a high efficiency of the magnetostrictive vibration power generation when both the longitudinal direction and the side surface direction are <100>. Therefore, in order to increase the degree of azimuth integration in the <100> direction and enhance the characteristics as a magnetostrictive material, it is advantageous to use a single crystal rather than a polycrystal. The plate-shaped member of the iron-gallium alloy is produced by growing a single crystal from a seed crystal by a crystal growth method to produce an ingot, and cutting the ingot in the above specific orientation.

As a method for growing a single crystal of an iron-gallium alloy, a pulling method (Czochralski method) (Patent Document 2), a VB method, and a VGF method are used.

However, in the pulling method, since the single crystal grows in a columnar shape, there is a problem that the number of man-hours increases when the single crystal is processed into a plate shape and a processing loss of the single crystal alloy occurs. Specifically, when the obtained ingot is columnar, an orifla is provided on <100> on the side surface of the columnar ingot using an X-ray diffractometer, and the plate-shaped member is formed in the above crystal orientation with reference to this orifra. Since it is processed, there is a problem that it takes a lot of labor and weight loss during processing.

On the other hand, the VB method has an excellent feature that a single crystal having a low dislocation density can be easily obtained because the temperature gradient in the crystal growth direction can be reduced. In addition, the outer shape of the single crystal is determined by the shape of the crucible, and it is grown according to the shape of the inner wall of the side surface of the crucible. For example, by making the cross-sectional shape of the small-diameter portion and the constant-diameter portion in the crucible a quadrangular shape in the crystal growth direction, it is possible to produce a prismatic single crystal ingot in which the upper surface and side crystal orientations are controlled in specific directions. (Patent Document 3).

In the iron-gallium alloy, if the upper surface and the four side surfaces of the prismatic single crystal are (100) planes, it is not necessary to orient the crystal planes and side surface processing in the cutting process to the plate-shaped member. Since weight loss due to processing is also reduced, reduction in processing cost can be expected. Then, when the method of Patent Document 3 is used, a seed crystal may be prepared so that the end face and the side surface in the longitudinal direction are (100) planes, and the seed crystal may be placed in the small diameter portion.

However, when the crucible is made into a prismatic shape, it is necessary to process it with high accuracy so that the side surface of the fixed diameter portion of the crucible and the side surface of the small diameter portion where the seed crystal is placed are in the same direction. Further, since it is necessary to install the seed crystal so that the side surface of the constant diameter portion of the crucible and the side surface of the seed crystal are parallel to each other, high accuracy is required for the installation of the seed crystal. When growing an iron-gallium alloy single crystal, alumina is used as a crucible material, so it requires advanced technology to accurately process the cross-sectional shape of a small diameter part with a side of about 10 mm into a quadrangle. there were.

The present inventors have made extensive studies to solve the above-mentioned problems. Then, if the orientation of the seed crystal can be controlled so that the side surface of the small diameter portion becomes the (100) plane while the small diameter portion has a cylindrical shape and the seed crystal has a cylindrical shape, the small diameter portion has a prismatic shape. It was noted that a single crystal ingot having a prismatic shape with all (100) planes on each side surface can be produced without forming the seed crystal into a prismatic shape.

However, since the diameter of the seed crystal is small, there is a limit to the accurate installation of the seed crystal even if the seed crystal is provided with a mark indicating the orientation or the orientation flare.

In the VB method and the VGF method, the present inventors have focused on melting the upper part of the seed crystal together with the raw material when growing the single crystal. Focusing on the fact that the upper surface shape of the seed crystal does not necessarily have to be parallel to the melt surface, the upper surface of the seed crystal is made an inclined shape, and the inclined direction is made to coincide with the <100> direction. , I found that the seed crystal can be installed with high accuracy. Then, the present inventors have completed the present invention from such findings. This will be described in detail below.

Using the iron-gallium alloy seed crystal and the seed crystal setting method according to the embodiment of the present invention, a prismatic single crystal ingot having all (100) planes on each side surface is grown by the VB method or the VGF method.

In the VB method or the VGF method, a seed crystal is placed at the bottom of the crucible (hereinafter referred to as a small diameter portion), and a raw material is charged at the top thereof. Next, the entire amount of the charged raw material and the upper 1/3 of the seed crystal are melted. Then, the single crystal is grown in a desired crystal orientation by gradually solidifying the melt from the position of the seed crystal by the temperature drop or the downward movement of the crucible.

The iron-gallium alloy according to the embodiment of the present invention preferably has a gallium content of 17 at% or more and 20 at% or less. When the gallium content is in this range, the iron-gallium alloy can obtain high magnetostrictive characteristics. When the gallium content is less than 17 at% and when the gallium content exceeds 20 at%, it becomes difficult for the iron-gallium alloy to obtain high magnetostrictive characteristics.

Here, the iron-gallium alloy has a body-centered cubic lattice structure, the first to third <100> axes of the directional indexes in the Miller index are equivalent, and the first of the plane indexes in the Miller index is equivalent. It is based on the fact that the third {100} plane is equivalent (that is, (100), (010) and (001) are equivalent).

(Single crystal growing device)
In order to more specifically explain the seed crystal and the seed crystal setting method of the iron gallium alloy according to the embodiment of the present invention, as an example of a growing device using the seed crystal and the seed crystal setting method, first, FIG. The single crystal growing apparatus shown will be described.

FIG. 1 is a schematic cross-sectional view of a single crystal growing device for growing an iron-gall alloy single crystal ingot according to an embodiment of the present invention. In FIG. 1, the positional relationship between the crucible 10 in the single crystal growing apparatus 100, the iron-gallium alloy seed crystal (hereinafter, also referred to as “seed crystal”) 16, and the raw material iron-gallium mixture 17 is schematically shown. There is.

The single crystal growing device 100 includes a heat insulating material 11, an upper heater 12a, a middle heater 12b, a resistance heating heater 12 composed of a lower heater 12c, a movable rod 13, a crucible receiver 14, a thermocouple 15, a vacuum pump 18, and a chamber. It has 19. The structure is such that the upper part of the chamber 19 has a high temperature and the lower part has a low temperature, and a melt of a mixture 17 of iron and gallium 17 is obtained by a unidirectional solidification crystal growth method such as the VB method or the VGF method. A single crystal ingot of an iron-gall alloy can be grown by gradually solidifying from the upper part of the seed crystal 16 in the crucible 10.

As shown in FIG. 1, in the single crystal growing apparatus 100, a carbon resistance heating heater 12 is arranged inside the heat insulating material 11. A hot zone is formed by the resistance heating heater 12 when growing a single crystal ingot of an iron-gallium alloy. The resistance heating heater 12 is composed of an upper heater 12a, a middle heater 12b, and a lower heater 12c, and the temperature gradient in the hot zone can be controlled by adjusting the input power to these heaters 12a to 12c. It has become. The heating method of the single crystal growing apparatus 100 is not particularly limited as long as a temperature gradient can be provided in the hot zone.

A crucible 10 is arranged inside the resistance heating heater 12, and is placed on a crucible receiver 14 (support stand) provided with a movable rod 13 that can move in the vertical direction. The lower part of the crucible 10 is filled with an iron-gallium alloy seed crystal 16, and the iron-gallium alloy seed crystal 16 is filled with a mixture 17 of iron and gallium as a raw material, such as particles or flakes.

A chamber 19 and a vacuum pump 18 are installed in the single crystal growing apparatus 100, and the inside of the chamber 19 can be adjusted to a vacuum atmosphere to grow a single crystal ingot of an iron-gall alloy. Further, an inert gas such as argon or nitrogen can be introduced into the chamber 19, and the inside of the chamber 19 can be adjusted to an inert atmosphere.

The material of the crucible 10 is preferably alumina, which has low chemical reactivity with the iron-gallium alloy and is a high melting point material. Further, magnesia and pyrolytic boron nitride may be used.

As described above, the crucible 10 is placed on the crucible receiver 14 provided with the movable rod 13 in the single crystal growing device 100, and by moving the movable rod 13 up and down, the crucible 10 is moved up and down in the growing furnace. Can be made to. Further, a thermocouple 15 capable of monitoring the temperature of the crucible is attached to the crucible 10.

(Crucible for growing prismatic single crystals)
A crucible in which a seed crystal according to an embodiment of the present invention is installed will be described with reference to FIG. FIG. 2 is a perspective view showing an example of the shape of a crucible in which a seed crystal according to an embodiment of the present invention is installed. By using the prism-shaped crucible 10 as shown in FIG. 2, a prism-shaped single crystal ingot that imitates the crucible shape is grown by the above-mentioned single crystal growing device. At this time, the prismatic single crystal is grown so that the plane in the growth axis direction is <100> and the side surfaces of the prismatic single crystal are all (100) planes.

The 坩 堝 10 has a well-shaped small diameter portion 10a on which a seed crystal is placed, an inverted quadrangular pyramid trapezoidal tubular diameter-increasing portion 10b whose diameter increases upward from the small-diameter portion, and upward from the diameter-increasing portion. It has a square tubular fixed diameter portion 10c that continues as a crystal growth portion. The side surface of the diameter-increasing portion 10b has an angle of 30 to 60 degrees with respect to the horizontal direction. This angle is preferably an angle of 40 to 50 degrees. If this angle is smaller than 40 degrees, the diameter-increasing portion becomes unnecessarily long and the cost increases. If the temperature is higher than 50 degrees, the problem of polycrystallization of the grown crystals tends to occur. It is preferably around 45 degrees. Further, the cross section of the small diameter portion 10a has a circular shape. Then, the cross section of the increased diameter portion 10b changes from a circular shape to a square shape between the contact point with the small diameter portion 10a and the contact point with the fixed diameter portion 10c. The cross section of the fixed diameter portion 10c has a square shape. Further, the crucible 10 has a shape such that the center points of the respective cross-sectional shapes are the same. The size and height of the small diameter portion 10a and the fixed diameter portion 10c are appropriately determined depending on the size and height of the seed crystal and the single crystal to be grown. Further, the size and height of the diameter-increasing portion 10b are appropriately determined so as to satisfy the above angles.

The cross section of the fixed diameter portion 10c is a square shape, and the upper surface and all side surfaces are (100) by adjusting the crystal orientation of the inclined surface of the seed crystal to coincide with the predetermined direction of the prismatic pit, as described later. It is possible to grow a prismatic single crystal ingot that is a surface. Further, by making the cross section of the small diameter portion 10a circular, that is, making the small diameter portion 10a cylindrical well, it becomes easy to rotate the seed crystal described later about the vertical direction, and the seed can be easily rotated. The crystal orientation of the inclined surface of the crystal can be easily adjusted. Then, the crystal orientation of the inclined surface of the seed crystal and the predetermined direction of the prismatic crucible can be easily matched. In the present application, the predetermined direction of the fixed diameter portion 10c of the pit is a direction that passes through the center of the square of the fixed diameter portion of the pit having a square cross section and intersects one side perpendicularly, and is one of the side surfaces of the fixed diameter portion 10c. The direction of the center of one side that is the same distance from the two corners on both sides of the side.

(Seed crystal)
A seed crystal according to an embodiment of the present invention will be described with reference to FIG. FIG. 3 is a perspective view showing a shape example of a seed crystal according to an embodiment of the present invention. The seed crystal 16 has a cylindrical shape, and one of the two end faces in the crystal growth direction of the seed crystal 16 has an inclined shape.

Since the seed crystal 16 has a cylindrical shape, as described above, it is easy to rotate the seed crystal about the vertical direction, and the crystal orientation of the inclined surface of the seed crystal can be easily adjusted. Then, the crystal orientation of the inclined surface of the seed crystal and the predetermined direction of the prismatic crucible can be easily matched.

Then, as shown in FIG. 3, the direction of inclination is set in the <100> direction perpendicular to the longitudinal direction. By adjusting the direction of <100> so as to coincide with a predetermined direction of the fixed diameter portion of the crucible, it is possible to grow a prismatic single crystal ingot whose upper surface and all side surfaces are (100) planes. The angle θ of inclination is appropriately adjusted depending on the inner diameter of the crucible, the length of the crucible, and the like, but is preferably 5 ° to 20 °. As will be described later, in the present invention, the reflected light when the laser beam or the like is reflected from above the seed crystal is visually recognized, and the crystal orientation of the inclined surface of the seed crystal and the predetermined direction of the prismatic pit are adjusted. When the inclination angle is smaller than 5 °, the reflected light is close to the incident light and cannot be visually recognized at the upper part of the crucible. If the inclination angle is larger than 20 °, the reflected light is reflected at a deep position on the side surface of the crucible, so that it is difficult to confirm the deviation of the reflected light. The surface of the inclined surface is not particularly limited as long as it reflects laser light or the like and can be visually recognized at the upper part of the crucible, but the inclined surface is processed into a mirror surface so that the light is reflected without being scattered. Is preferable. The size of the seed crystal 16 is not particularly limited.

Next, the reflected light when the laser beam or the like is reflected from above the seed crystal according to the embodiment of the present invention will be described in detail with reference to FIG. FIG. 4 is a schematic perspective view showing the crystal orientation of the inclined surface of the seed crystal and the light reflection on the upper surface of the seed crystal according to the embodiment of the present invention.

As shown in FIG. 4, the direction of inclination of the upper surface 16a of the seed crystal is set to the <100> direction perpendicular to the longitudinal direction. Then, a laser beam or the like is incident on the upper surface 16a of the seed crystal from above the seed crystal 16 in parallel with the longitudinal direction of the seed crystal 16. The reflected light is reflected in the direction forming the inclination angle θ with the longitudinal direction of the seed crystal 16. Further, since the inclination direction of the upper surface 16a of the seed crystal is the <100> direction perpendicular to the longitudinal direction, the reflected light is reflected along the <100> direction perpendicular to the longitudinal direction as shown in FIG.

Then, as shown in FIG. 4, the plane formed by the incident light and the reflected light forms a (100) plane which is a plane composed of two <100> directions. Further, a plane formed by the <100> direction perpendicular to the longitudinal direction and the inclined direction and the longitudinal direction also forms the (100) plane. Further, since the iron-gallium alloy has a body-centered cubic structure and all the axial angles are 90 °, these (100) planes can be formed. By tilting the upper surface 16a of the seed crystal in the <100> direction in advance, the reflected light can be easily reflected along the <100> direction perpendicular to the longitudinal direction.

By matching the <100> direction, which is the direction of inclination of the upper surface 16a of the seed crystal, with the direction that passes through the center of the square of the fixed diameter portion of the pit whose cross section is square and intersects perpendicularly with one side, the fixed diameter portion of the pit. All four sides are in the <100> direction perpendicular to the longitudinal direction, and all the side surfaces of the constant diameter portion form a (100) plane.

(How to install seed crystals)
A method for installing a seed crystal according to an embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic perspective view illustrating a method of installing a seed crystal according to an embodiment of the present invention.

First, the seed crystal 16 is placed on the small diameter portion 10a of the crucible 10 with the inclined surface facing up. Next, the upper surface of the seed crystal 16 is irradiated with laser light or the like from the light source 20 above the crucible in parallel with the longitudinal direction of the seed crystal 16. As shown in FIG. 5, the reflected light is reflected in the <100> direction perpendicular to the longitudinal direction of the seed crystal. Then, the reflected light is visually recognized at the upper part of the crucible. There is no limit to the type of light as long as the reflected light can be visually recognized other than the laser light. The position of the laser beam is preferably aligned with the crucible axis, but may be tilted if necessary. The method is not particularly limited as long as the orientation of the seed crystal 16 and the position of the crucible body can be aligned based on laser light or the like.

Further, the point where the reflected light intersects perpendicularly with one side of the fixed diameter portion 10c side surface of the crucible 10, that is, the center of one side that is the same distance from the two corners on both sides of one side of the fixed diameter portion 10c. , Set as a reference position. When the direction of the inclined surface of the seed crystal 16 is parallel to each side of the fixed diameter portion 10c cross section, the reflected light coincides with the reference position.

If there is a discrepancy between the position of the reflected light and the reference position value at the top of the crucible, the seed crystal 16 is rotated so that the misalignment disappears. The method of rotation is not particularly limited. For example, it may be rotated from the outside of the crucible 10 by using a magnet or the like. Further, the seed crystal may be sandwiched and rotated from above the crucible. In this case, the length of the seed crystal is preferably longer than that of the small diameter portion. It is possible to sandwich and rotate the portion protruding from the upper end of the small diameter portion. By the above method, the alignment of the crystal orientation of the inclined surface of the seed crystal 16 and the predetermined direction of the crucible can be easily set. Then, it is possible to grow a prismatic single crystal ingot whose upper surface and all side surfaces are (100) planes.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

From an iron gallium single crystal having a gallium content of 18 at%, a columnar seed crystal having a (100) plane in the longitudinal direction <100>, that is, in the direction perpendicular to the longitudinal direction was prepared. The seed crystal has a cylindrical shape with a height of 30 mm and a diameter of 10 mmφ, and the upper surface of the cylinder is provided with an inclination of 15 ° with respect to the <100> direction perpendicular to the longitudinal direction, and the inclined surface does not scatter light. It was processed into a mirror surface so that it would be reflected.

Next, as a crucible, a cylindrical well shape with a thickness of 3 mm, an inner diameter of a small diameter part of φ10 mm, a height of 30 mm with a closed lower end, and a substantially inverted quadrangular pyramid trapezoidal shape with a half-diameter angle of 45 °. A crucible made of dense alumina having a fixed diameter portion of 50 mm × 50 mm square and a total height of 200 mm was prepared, and seed crystals were placed in the small diameter portion. Then, a laser beam parallel to the longitudinal direction of the seed crystal is irradiated on the upper surface of the seed crystal installed in the small diameter portion so that the reflected light of the laser beam intersects one side of the side surface of the fixed diameter portion of the pit perpendicularly. That is, the direction of reflection of the laser beam is adjusted by rotating the seed crystal using a magnet so that the laser beam is located at the center of one side that is the same distance from the two corners on both sides of the side surface of the fixed diameter portion. did. After that, a mixture of iron and gallium was charged in the crucible so that the gallium content was 18 at%, and a single crystal of the iron-gallium alloy was grown by the VB method. When the crystal orientation of one side of the side surface of the straight body of the obtained single crystal was measured by an X-ray diffractometer, the deviation from <100> was 0.58 ° in the direction parallel to the crystal growth direction. ..

The single crystals were grown 9 times in the same procedure, and the crystal orientation of each single crystal was confirmed. The results are shown in Table 1. Table 1 shows the results of measuring the deviation between the crystal orientation of the side surface of the iron-gallium alloy single crystal and the <100> direction.

It was confirmed that the deviation from <100> was within 1 ° in all the crystals. As described above, it can be seen that the iron gallium single crystal is grown into a prismatic shape having a quadrangular cross-sectional shape of the straight body, and the crystal orientation of <100> is secured on one side of the quadrangle. Therefore, the cutting process can be performed along the (100) plane which is the crystal side surface. As a result, it is not necessary to renew the crystal plane measurement and the orientation flat processing of the grown crystal with the X-ray diffractometer, and the weight loss due to the processing is also reduced.

Although one embodiment of the present invention and each embodiment have been described in detail as described above, those skilled in the art will be able to make many modifications that do not substantially deviate from the novel matters and effects of the present invention. , Will be easy to understand. Therefore, all such modifications are included in the scope of the present invention.

For example, a term described at least once in a specification or drawing with a different term in a broader or synonymous manner may be replaced by that different term anywhere in the specification or drawing. Further, the seed crystal used for growing the single crystal, the method for installing the seed crystal, and the structure of the crucible are not limited to those described in one embodiment of the present invention and each embodiment, and various modifications can be carried out.

10 crucible, 10a small diameter part, 10b diameter increase part, 10c fixed diameter part, 11 heat insulating material, 12 resistance heating heater, 12a upper heater, 12b middle heater, 12c lower heater, 13 movable rod, 14 crucible receiver, 15 thermocouple Pair, 16 seed crystals, 16a seed crystal top surface, 17 iron and gallium mixture, 18 vacuum pump, 19 chambers, 20 light sources, 100 single crystal growth device

Claims (9)

A seed crystal for growing a single crystal by the VB method or the VGF method.
The seed crystal has a cylindrical shape and has a cylindrical shape.
The upper surface of the seed crystal is an inclined surface,
The seed crystal is characterized in that the inclined surface is inclined in a specific crystal orientation. The seed crystal according to claim 1, wherein the seed crystal is a single crystal of an iron-gallium alloy. The seed crystal according to claim 1 or 2, wherein the crystal orientation is in the <100> direction perpendicular to the growth direction of the single crystal. It is a method of setting a seed crystal for growing a single crystal using a crucible by the VB method or the VGF method.
The cross section of the fixed diameter portion of the crucible is square,
The seed crystal has a cylindrical shape and has a cylindrical shape.
The upper surface of the seed crystal is an inclined surface,
The inclined surface is inclined to a specific crystal orientation,
The seed crystal is placed in the small diameter portion of the crucible,
Installation of the seed crystal, which is characterized in that the seed crystal is installed so that the predetermined direction of the constant diameter portion of the pit and the crystal orientation coincide with each other by using the reflection position of the light beam reflected from the upper surface of the seed crystal. Method. The method for installing a seed crystal according to claim 4, wherein the seed crystal is a single crystal of an iron-gallium alloy. The method for installing a seed crystal according to claim 4 or 5, wherein the small-diameter portion for installing the seed crystal of the crucible has a cylindrical well shape. The crystal orientation is the <100> direction perpendicular to the growth direction of the single crystal.
The method for installing a seed crystal according to any one of claims 4 to 6, wherein the deviation between the predetermined direction of the constant diameter portion of the crucible and the crystal orientation is within 1 °. A crucible for growing a single crystal by the VB method or the VGF method.
The cross section of the fixed diameter portion of the crucible is square,
A crucible for growing a single crystal, characterized in that the cross section of the small diameter portion on which the seed crystal of the crucible is placed is circular. The crucible for growing a single crystal according to claim 8, wherein the single crystal is a single crystal of an iron-gallium alloy.

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