JP6473649B2 - Laser single crystal growth apparatus and single crystal - Google Patents

Description

  The present invention relates to a laser single crystal growth apparatus and a single crystal.

  Conventionally, a method of irradiating a raw material rod with a plurality of heating laser beams from the surroundings using a plurality of heating laser sources has been proposed, compared to a floating melting zone method using halogen lamp heating. The method using a plurality of heating laser beams can distinguish the melting zone where the raw material is melted from the liquid temperature distribution at the crystal interface. Thereby, it is possible to stably take out the crystal phase from the decomposition melt type liquid.

  FIG. 30 shows a conventional single crystal growth apparatus 500 using a halogen lamp heating method. In the single crystal growing apparatus 500, an infrared lamp such as a halogen lamp 520 is disposed at the left and right focal positions of the confocal ellipsoidal reflecting mirror 530. Further, a quartz tube 510 is disposed at the center position of the two confocal ellipsoidal reflecting mirrors 530, and a raw material rod 501 is placed in the quartz tube 510. Thereby, the single crystal growing apparatus 500 condenses the reflected light from the left and right confocal ellipsoidal reflecting mirrors 530 and melts the raw material bar 501. The molten part is held in a balance of the viscosity of the melt, the surface tension, and the weight of the molten part. In the case of a material having a large melting portion and low viscosity, the upper and lower gaps of the melting portion must be narrowed in order to maintain the melting zone. If this gap is wide, the melted part hangs down on the crystal rod, and the melted part cannot be maintained. In order to increase the diameter of the crystal rod, the gap between the melting zones must be increased. This is to increase the melting material supplied to the crystal rod and to maintain the melting zone temperature. However, the change of the heating range cannot be realized because it changes the basic structure of the single crystal growth apparatus 500.

  On the other hand, the laser beam heating method also has some problems. First, it is not realistic to adjust the optical path, shape, and intensity distribution of the five laser irradiation lights shaped into a substantially square shape that is not visible light. In particular, when the laser irradiation light shape changes frequently, the confirmation operation of the laser irradiation light shape accompanying the change of the laser irradiation light shape cannot be realized each time. The wavelength of the heating laser light uses an infrared wavelength. This wavelength region can efficiently heat the raw material rod. In this wavelength region, semiconductor laser devices having high laser light intensity are supplied. However, infrared light cannot be seen with the naked eye. For this purpose, an infrared / visible light conversion panel is used, infrared light is irradiated onto the conversion panel, and the position and irradiation shape of the heating laser light are confirmed with visible light emitted on the irradiation panel. However, it is difficult and impractical to adjust a large number of infrared laser irradiation lights by such a method. In the adjustment, the output of the semiconductor laser is adjusted as low as possible. However, since the incident of scattered light on the eye is very dangerous, infrared light blocking goggles are obligatory, and workability is impaired. Further, the emission intensity of the converted visible light is extremely weak, and is insufficient for adjustment. The shape and intensity distribution of the M heating laser beams irradiated to the raw material rod cannot be confirmed freely.

  Secondly, the problem of directly observing the temperature of the melting zone in the raw material rod has not been known. In addition to the black body radiation known from Planck's equation, the radiation from the melting zone includes intense scattered light of the heating laser light. Therefore, the conventional radiation thermometer cannot block the strong scattered light of the heating laser beam, and the temperature of the melting zone cannot be directly observed.

  Thirdly, in the laser beam heating method, heating to other than the melting zone is drastically reduced, so that the upper and lower sides of the melting zone become dark. Therefore, it becomes impossible to observe the state of the upper and lower crystal rods and the raw material part of the melting zone.

  Fourthly, the laser beam heating method showed excellent characteristics for obtaining a single crystal of a decomposed and melted material by making the temperature distribution between the melting zone and the crystal rod steep. However, on the other hand, the crystal part grown by the laser beam heating method is rapidly cooled. For this reason, strain may remain in the portion of the grown crystal rod. Certain materials cause serious problems such as cracks in the grown crystal parts. If the crack extends to the entire crystal, a desired single crystal cannot be obtained.

  In the first aspect of the present invention, in a single crystal growth apparatus using M heating laser beams, one heating laser beam is generated based on one laser power source and the power supplied by one laser power source. One semiconductor laser device that emits light, a laser beam splitting device that splits one semiconductor laser beam into M heating laser beams, and M heating laser beams about the central axis of the raw material rod M laser irradiation heads that irradiate the raw material rod radially with a rectangular irradiation light shape, one reference light laser device that irradiates the raw material rod with the reference laser light, and the reference laser light to the laser light splitting device as a semiconductor laser A single crystal comprising: an optical path integrating unit that leads to the same optical path as the light; a temperature measuring unit that measures the temperature of the raw material rod; and an output control unit that controls the output of M heating laser beams based on the temperature of the raw material rod A training device is provided.

  According to a second aspect of the present invention, there is provided a single crystal growth apparatus including M laser irradiation heads capable of changing a substantially square irradiation shape having a top flat irradiation intensity distribution of M heating laser beams.

  In the third aspect of the present invention, a single crystal provided with M laser irradiation heads capable of changing the top-flat irradiation intensity distribution of M heating laser beams into a bell-shaped intensity distribution and changing the substantially rectangular irradiation shape. A training device is provided.

  In the fourth aspect of the present invention, there is provided a heating auxiliary unit that has N reflecting mirrors and N heating halogen lamps, reflects the light irradiated by the heating halogen lamps to the reflecting mirror, and irradiates the raw material rod. A single crystal growth apparatus according to the first aspect, further comprising:

  The fifth aspect of the present invention further includes a melting zone monitoring unit that monitors a melting zone in the raw material rod, and the melting zone monitoring unit attenuates the radiation light from the raw material rod and a camera that acquires an image of the raw material rod. And the optical filter provides the single crystal growth apparatus according to the first aspect or the second aspect, which includes two polarizers.

  According to a sixth aspect of the present invention, there is provided the single crystal growth apparatus according to any one of the first to fifth aspects, further comprising a magnetic field applying unit that applies a magnetic field to the raw material rod.

  According to a seventh aspect of the present invention, there is provided the single crystal growing apparatus according to any one of the first aspect to the fifth aspect, further comprising a high-frequency applying unit that applies a high frequency to the raw material rod.

  In an eighth aspect of the present invention, a method for producing a single crystal of an iron oxide compound having a Y, W, Z type ferrite structure using the single crystal growth apparatus according to any of the first to seventh aspects I will provide a.

  The summary of the invention does not enumerate all the features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

An outline of the configuration of the single crystal growing apparatus 100 is shown. An example of the top view of the structure of the single crystal growth apparatus 100 is shown. An example of the perspective view of the single crystal growth apparatus 100 is shown. The time dependence of the measured temperature of the raw material stick | rod 1 is shown. An example of the structure of the laser irradiation head 21 is shown. An observation photograph of the reference laser beam 6 at the position of the raw material rod 1 is shown. The actual measurement result of the light intensity distribution from the laser irradiation head 21 which concerns on Example 1 is shown. 1 shows a configuration example of a laser beam splitter 130 according to a first embodiment. The relationship between the temperature (degree) of the raw material stick | rod 1 and the irradiation light intensity (W) from a laser irradiation head is shown. FIG. 10A shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 3 mm × 8 mm. FIG. 10B shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 4 mm × 8 mm. FIG. 10C shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 10 mm × 10 mm. FIG. 10D shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 15 mm × 15 mm. The actual measurement result of intensity distribution of irradiation light of 3 mm × 8 mm is shown. The actual measurement result of the intensity distribution of irradiation light of 10 mm × 10 mm is shown. The actual measurement result of the intensity distribution of irradiation light of 15 mm × 15 mm is shown. FIG. 14A shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 3 mm × 10 mm. FIG. 14B shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 5 mm × 10 mm. FIG. 14C shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 10 mm × 10 mm. 8 shows a configuration example of a single crystal growth apparatus 100 according to Example 7. FIG. 16 (a) shows a photograph of the vicinity of the melting zone when there is no irradiation light when the raw material rod 1 is heated. FIG. 16 (b) is a photograph of the vicinity of the melting zone when irradiated with high-intensity diode light. It is a photograph of the Y-type ferrite single crystal rod of chemical formula A ₂ B ₂ C ₁₂ O ₂₂ . It is a photograph of a W-type ferrite single crystal rod of chemical formula AB ₂ C ₁₆ O ₂₇ . It is a photograph of the Z-type ferrite single crystal rod of the chemical formula A ₃ B ₂ C ₂₄ O ₄₁ . An example of the configuration of the melting zone monitoring unit 54 is shown. 21 (a) and 21 (b) show a more detailed view of the polarizer rotator 56. FIG. An example of the structure of the laser irradiation head 21 is shown. An example of the structure of the laser irradiation head 21 is shown. An example of the structure of the single crystal growth apparatus 100 provided with the auxiliary heating part 80 is shown. An example of a top view of the auxiliary heating unit 80 is shown. An example of the temperature in the vicinity of the melting zone 4 is shown. An example of the structure of the single crystal growth apparatus 100 provided with the auxiliary heating part 80 is shown. The structural example of the single crystal growth apparatus 100 provided with a magnetic field application part is shown. The structural example of the single crystal growth apparatus 100 provided with a high frequency application part is shown. A halogen lamp heating method having a confocal ellipsoidal mirror surface is shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 shows an example of a perspective view of a single crystal growing apparatus 100. The single crystal growth apparatus 100 includes M laser irradiation heads, M fibers, and an optical stage 140 for fixing those optical systems. Under the optical bench 140, a laser power source 110, a semiconductor laser device 120, a laser beam splitting device 130, a reference beam laser device 150, and an optical path integrating unit 155 are arranged.

  The single crystal growing apparatus 100 is an apparatus for growing a single crystal by irradiating the raw material rod 1 with the heating laser beam 3 by a floating melting zone method.

  The semiconductor laser device 120 is driven by the power supply from the laser power supply 110 to generate the semiconductor laser light 5. The semiconductor laser device 120 emits the generated semiconductor laser light 5 to the laser beam splitter 130. The single crystal growth apparatus 100 of this example has one laser power source 110 and one semiconductor laser apparatus 120.

  The laser beam splitter 130 splits the semiconductor laser beam 5 into M pieces. The laser beam splitter 130 makes the divided semiconductor laser beam 5 incident on the fibers 31, 32, 33, 34, and 35. The laser beam splitter 130 of this example splits the semiconductor laser beam 5 into five.

  The reference light laser device 150 generates the reference laser light 6. The reference light laser device 150 makes the generated reference laser light 6 enter the optical path integration unit 155. The single crystal growth apparatus 100 of this example has one reference light laser apparatus 150 integrated with a reference laser power source.

  The optical path integrating unit 155 makes the incident semiconductor laser beam 5 and reference laser beam 6 enter the laser beam splitting device 130 through the same optical path. Although the optical path integration unit 155 of this example is configured by a half mirror, a split mirror, a prism, a triangular prism mirror, or the like may be used. Further, by reversing the traveling direction of the laser incident on the laser beam splitter 130, the optical system shown by the laser beam splitter 130 can be used as the optical path integrating unit 155.

  The laser beam splitting device 130 splits the reference laser beam 6 into M pieces. The laser beam splitter 130 makes the divided reference laser beam 6 incident on the fibers 31, 32, 33, 34, and 35. The laser beam splitter 130 of this example splits the reference laser beam 6 into five.

  The raw material rod 1 is a cylindrical rod formed of a material corresponding to a single crystal to be grown. For example, the diameter of the raw material stick 1 is 2 mm to 15 mm. The raw material rod 1 is heated with the heating laser beam 3 to form a melting zone 4 on the crystal rod 2. For example, the melting temperature of the raw material rod 1 is 300 ° C. to 2000 ° C. The melting zone 4 is a layer in which the raw material rod 1 is melted by the heating laser beam 3, and a single crystal corresponding to the material of the raw material rod 1 is grown by descending the crystal rod. The raw material rod 1 and the crystal rod 2 are installed in a quartz tube and fixed to the raw material rod holding part 11 and the single crystal holding part 12, respectively. Since the single crystal growing apparatus 100 of this example does not need to place the raw material rod 1 in the crucible, it can grow an extremely high-purity single crystal rod without contamination from the crucible. It is also possible to add a trace amount of element to the raw material rod 1.

  The raw material rod holding unit 11 holds the raw material rod 1 in the quartz tube. The raw material rod holding part 11 rotates the raw material rod 1 counterclockwise with respect to the central axis of the raw material rod 1 in plan view. For example, the raw material rod holding part 11 has a shaft, and the raw material rod 1 is suspended from the shaft by a high melting point wire such as a platinum wire. What is necessary is just to determine the rotational speed of the raw material stick | rod 1 to arbitrary speeds, and is about 10-60 rpm in an example.

  Single crystal holding unit 12 holds crystal rod 2 in a quartz tube. The single crystal holding unit 12 rotates the crystal rod 2 clockwise with respect to the central axis of the crystal rod 2 in plan view. That is, the raw material rod holding unit 11 and the single crystal holding unit 12 rotate so that the rotation direction of the raw material rod 1 and the rotation direction of the crystal rod 2 are opposite to each other. What is necessary is just to determine the rotational speed of the crystal | crystallization rod 2 to arbitrary speeds, and is about 10-60 rpm in an example. The rotation speed of the crystal rod 2 is preferably the same as the rotation speed of the raw material rod 1, but is not limited thereto. By rotating the raw material rod 1 and the crystal rod 2, the temperature uniformity of the melting zone 4 is improved.

  The raw material bar holding unit 11 and the single crystal holding unit 12 gradually move the holding positions of the raw material bar 1 and the crystal bar 2 downward while the melting zone 4 is stabilized at a predetermined temperature. Thereby, it is gradually crystallized from a region where the melting zone 4 is no longer irradiated with the heating laser beam 3. The moving speed of the raw material rod holding unit 11 and the single crystal holding unit 12 is arbitrarily set according to the characteristics of the single crystal material, the intensity of the heating laser beam 3, and the like.

  The laser irradiation heads 21, 22, 23, 24, and 25 shape the light incident from the fibers 31, 32, 33, 34, and 35 with a lens, and generate the heating laser light 3 having a substantially square irradiation intensity distribution. The laser irradiation heads 21, 22, 23, 24, and 25 are arranged so as to radiate a plurality of heating laser beams 3 radially with respect to the central axis of the raw material rod 1 and at equal intervals. That is, the laser irradiation heads 21, 22, 23, 24, and 25 irradiate the heating laser light 3 from five directions at an angle of about 72 degrees around the raw material rod 1.

  The laser irradiation heads 21, 22, 23, 24, and 25 shape the reference laser light 6 incident from the fibers 31, 32, 33, 34, and 35 with a lens in the same manner as the heating laser light 3, and the heating laser light 3 The reference laser beam 6 having the substantially square irradiation intensity distribution is generated. The reference laser beam 6 is visible light, and a wavelength close to the infrared wavelength region used for the heating laser beam 3 is selected. This is to make the refractive index of the laser irradiation head lens or the like close to that of infrared light. The laser irradiation heads 21, 22, 23, 24, and 25 irradiate a plurality of reference laser beams 6 radially with respect to the central axis of the raw material rod 1 and at equal intervals. The reference laser beam 6 may be irradiated at the stage of adjusting the heating laser beam 3.

  FIG. 2 shows an example of a top view of the configuration of the single crystal growing apparatus 100. FIG. 3 shows an example of a perspective view of the single crystal growing apparatus 100. The single crystal growing apparatus 100 further includes a quartz tube 10, M dampers, a photodetector 53, a melting zone monitoring unit 54, and an output control unit 70. In this example, the number M = 5 is shown.

  The quartz tube 10 is a transparent tube made of quartz. The raw material rod 1 is disposed on the central axis of the quartz tube 10. The quartz tube 10 is filled with a suitable gas according to the material of the raw material rod 1 and the like. For example, oxygen gas is supplied to the quartz tube 10 and the inside of the quartz tube 10 is adjusted to a predetermined pressure.

  The dampers 41, 42, 43, 44, 45 have a water cooling mechanism and absorb a part of the heating laser beam 3. The dampers 41, 42, 43, 44, and 45 are provided to face the laser irradiation heads 21, 22, 23, 24, and 25, respectively, with the raw material rod 1 interposed therebetween. For example, the damper 41 absorbs the heating laser light 3 that has passed through the left and right of the raw material rod 1 among the heating laser light 3 output from the laser irradiation head 21. Thereby, damage inside the single crystal growing apparatus 100 by the laser irradiation head 21 can be prevented.

  The temperature measurement unit 50 optically measures the temperature of at least a part of the melting zone 4. More specifically, the temperature measuring unit 50 measures the temperature of the melting zone 4 by detecting the emitted light of the heated raw material rod 1 or the melting zone 4. That is, the temperature measuring unit 50 can measure the temperature of the melting zone 4 at the same time that the heating laser light 3 from the laser irradiation head is irradiated onto the raw material rod 1. The temperature measurement unit 50 includes a lens 51, a filter 52, and a light detector 53.

  The lens 51 is used to limit a heating region that is a target of temperature measurement. For example, the lens 51 limits the heating area to be temperature-measured to an area within 2 mmφ.

  The filter 52 includes a spectroscope or an optical filter, and blocks the heating laser light 3 and illumination light described later from entering the photodetector 53. In addition, the temperature measurement part 50 may limit the range of the area | region of temperature measurement by providing a pinhole, and may interrupt | block the light from others.

  The light detector 53 receives light incident through the lens 51 and the filter 52. For example, the photodetector 53 has an InGaAs sensor. Since the InGaAs sensor has a detection wavelength range in the far-infrared wavelength range, even the light after passing through the filter 52 can detect the radiation light sufficient to detect the temperature of the melting zone 4. The InGaAs sensor is sensitive to radiation from the black body when the raw material rod 1 and the crystal rod 2 are black bodies. Therefore, an InGaAs sensor is suitable as the photodetector 53.

  The light detector 53 calibrates the output voltage of the sensor based on the radiation light from the black body of the raw material rod 1 or the crystal rod 2. Thereby, the light detector 53 converts the temperature of the melting zone 4 from the output voltage of the sensor. In the conventional single crystal growing apparatus using the confocal ellipsoidal reflector, the confocal ellipsoidal reflector completely covers the raw material rod 1, so that the lens 51, the filter 52, and the photodetector 53 like the temperature measuring unit 50. An optical measurement system equipped with cannot be installed. In the laser heating type single crystal growth apparatus 100, the temperature measuring unit 50 can be arranged, so that the temperature of a narrow region in the melting zone 4 can be measured with high accuracy. As described above, the temperature measuring unit 50 of this example measures the temperature of the melting zone 4 by a non-contact measurement method that is completely different from the temperature measurement by the conventional thermocouple.

  The melting zone monitoring unit 54 images the melting zone 4. The melting zone monitoring unit 54 of this example includes a camera 55 and a polarizer rotating device 56. The camera 55 acquires an image in the vicinity of the melting zone 4. The polarizer rotating device 56 is composed of two polarizers, and polarizes the emitted light from the melting zone 4. The single crystal growing apparatus 100 may control the output control unit 70 according to the crystallinity of the single crystal by acquiring an image in the vicinity of the melting zone 4.

  The output control unit 70 changes the irradiation intensity of the heating laser beam 3 based on the temperature of the melting zone 4 measured by the temperature measurement unit 50. Further, the output control unit 70 may change the irradiation intensity of the heating laser light 3 based on the image of the melting zone 4 acquired by the melting zone monitoring unit 54. In one example, the output control unit 70 controls the temperature of the melting zone 4 by a PID (Proportional Integral Derivative) control method. PID control is a control method performed based on three elements, P (proportional control), I (integral control), and D (differential control). The output control unit 70 performs PID control on the power supplied to the semiconductor laser device 120 to control the irradiation intensity of the heating laser light 3. For example, the output control unit 70 increases the irradiation intensity of the heating laser light 3 by increasing the power supplied from the laser power supply 110 when the temperature of the melting zone 4 is lower than a predetermined temperature. When controlling a plurality of semiconductor laser devices, the outputs of a plurality of laser power sources are controlled. The intensity of the semiconductor laser beam 5 from the semiconductor laser device 120 is substantially linear with respect to the supplied power, but has a different function form. Therefore, it is necessary to determine the power supplied from the plurality of laser power sources 110 based on data obtained by measuring the relationship between the laser power source 110 and the laser output intensity in advance. Further, this function changes with the elapsed use time of the heating laser beam 3. That is, when a plurality of semiconductor laser devices are used, it has been difficult to control the output of each semiconductor laser device, which is not practical.

  On the other hand, the single crystal growth apparatus 100 disclosed in this specification may control one laser power source. Since there is only one function form of the semiconductor laser light output intensity and the supplied power, PID control may be used. Further, the change with time of the semiconductor laser light may be monitored periodically. According to PID control, it is only necessary to change an appropriate control parameter. The heating laser beam 3 can be easily controlled by measuring the temperature of the raw material rod 1 and the melting zone 4. Further, the output control unit 70 may change the size of the irradiation light shape of the heating laser light 3 according to the shape of the raw material rod 1, the temperature, stability, height, and width of the melting zone 4.

[Example 1]
FIG. 4 shows the time dependence of the measured temperature when a sintered bar of Y-type ferrite of SrBaCoZnFe ₁₁ AlO ₂₂ is used as the raw material bar 1. The vertical axis indicates the temperature (degrees) of the raw material rod 1, and the horizontal axis indicates time (hours). The wavelength of the semiconductor laser beam 5 is 940 nm. One semiconductor laser beam 5 having a wavelength of 940 nm is irradiated by power supplied from one semiconductor power source. One semiconductor laser beam 5 is divided into five by a laser beam splitting device 130 and condensed into five fibers. The semiconductor laser beam 5 from the fiber formed into a substantially quadrangular shape was irradiated to the raw material rod 1 from five directions by five irradiation heads with five heating laser beams 3 having a top flat irradiation intensity distribution of 4 mm × 8 mm. The raw material rod 1 rotates at 20 rpm.

  It can be seen that the temperature variation shown in FIG. 4 is within the temperature range of ± 1 ° C. The extremely small temperature fluctuation of the rotating raw material rod 1 is realized by the following procedure. An irradiation shape of the semiconductor laser beam 5 and a top flat irradiation light intensity distribution are prepared. In order to realize the irradiation shape of the semiconductor laser light 5, the laser irradiation head is adjusted so that the irradiation light shape on the raw material rod 1 becomes the irradiation shape of the desired semiconductor laser light 5 with the reference laser light 6. Since the reference laser beam 6 is a light having a wavelength in the visible region, the irradiation light can be easily adjusted. The wavelength of the reference laser beam 6 used in Example 1 is 655 nm, and the output intensity is 1 mW.

  FIG. 5 shows an example of the configuration of the laser irradiation head 21. The laser irradiation head 21 includes a parallel light generation unit 26 and a laser condensing unit 27.

  The laser irradiation head 21 outputs a reference laser beam 6 having an irradiation light shape of 4 mm × 8 mm. In this specification, the description of Amm × Bmm as the irradiation light shape of the laser light indicates that the height of the irradiation light shape is Amm and the width of the irradiation light shape is Bmm. That is, the height of the irradiation light shape of the reference laser light 6 is 4 mm, and the width of the irradiation light shape of the reference laser light 6 is 8 mm. Although the height of the irradiation light shape in this example is 4 mm, 3 mm may be selected when the viscosity of the melting zone 4 is low. The laser irradiation head 21 heats the raw material rod 1 having a height of 4 mm irradiated with the reference laser beam 6. Note that the reference laser beam 6 of this example has a top-flat irradiation light intensity distribution.

  The parallel light generation unit 26 includes a single convex lens and converts the reference laser light 6 from the fiber 31 into parallel light. The exit shape of the fiber 31 is a regular square, and the exit at the fiber 31 has a two-dimensional radiation intensity distribution. In order to prevent adhesion of dust and the like in the surrounding environment, the irradiation light exit of the parallel light generation unit 26 is covered with a transparent protective glass. The parallel light generator 26 is a cylindrical device and is fixed to the optical bench by an annular fixing jig d1.

  The laser condensing unit 27 converts the regular rectangular column-shaped parallel light from the parallel light generation unit 26 into a substantially rectangular irradiation light shape having a desired size. The laser condensing unit 27 includes a cylindrical lens and a convex lens having a horizontal axis and a vertical axis. The cylindrical lens includes a cross section having a curved surface and a cross section having no curved surface. By using a cylindrical lens, the ratio of the height and width of the irradiation light shape can be changed. The left and right entrance and exit sides of the laser focusing unit 27 are covered with transparent protective glass. The laser condensing unit 27 is a cylindrical device and is fixed to the optical bench by an annular fixing jig d2.

  FIG. 6 shows a photograph at the position of the raw material rod of the irradiation light shape of the reference laser beam 6 of the laser irradiation head 21 according to the first embodiment. It can be seen from the irradiation optical system shown in FIG. 5 that the reference laser beam 6 has an irradiation light shape of 4 mm × 8 mm. The peripheral circular spread is due to the fact that the antireflection film thickness of the laminated multilayer film applied to the lens is optimized with the wavelength of the infrared light of the heating laser beam 3. This is because multiple reflections occur at the wavelength in the visible region of the reference laser beam 6 and scattered light is generated around the square shape. The cylindrical lens is designed so that the irradiation light intensity distribution of the reference laser beam 6 has a top-flat intensity distribution with a 4 mm × 8 mm irradiation light shape. The other four laser irradiation heads also use the reference laser light 6 to adjust the height and direction of the laser irradiation heads so that the heights of the five beams coincide with the central axis of the raw material rod 1. Further, the lens position is adjusted so that the five reference laser beams 6 are focused on the central axis of the raw material rod 1. Thus, after adjusting the arrangement of the laser irradiation head 21 and the lens system with the reference laser light 6 that is visible light, the irradiation shape and intensity distribution of the heating laser light 3 having a wavelength in the infrared region have a desired irradiation shape. And a two-dimensional infrared sensor to confirm that the intensity distribution is present. This one-to-one confirmation may be performed once.

  FIG. 7 shows an actual measurement example of the two-dimensional infrared sensor of the two-dimensional irradiation intensity of the heating laser beam 3 at the raw material bar position according to the first embodiment. It can be seen that an irradiation light shape of 4 mm × 8 mm is realized. The irradiation intensity A of the heating laser beam 3 indicates the intensity distribution of the heating laser beam 3 on the horizontal axis a indicated by a broken line. That is, the irradiation intensity A indicates the intensity distribution in the width direction of the heating laser beam 3. On the other hand, the irradiation intensity B of the heating laser beam 3 indicates the intensity distribution of the heating laser beam 3 on the vertical axis b indicated by a broken line. That is, the irradiation intensity B indicates the intensity distribution of the heating laser beam 3 in the height direction. The vertical axis b coincides with the central axis of the raw material bar 1. From the measurement result of this example, although the end of the heating laser beam 3 is slightly deformed, it has a very good rectangular shape. In addition, the irradiation intensity A of the heating laser beam 3 is a trapezoidal irradiation light intensity distribution at the cut surface of the vertical axis b and the horizontal axis a, and the variation in the irradiation intensity on the upper side of the trapezoidal intensity distribution is It is within ± 5% of the irradiation light intensity. The irradiation light intensity distribution of almost perfect top flat is shown. It is confirmed that the two-dimensional irradiation intensity distribution of the heating laser beam 3 from the other four irradiation heads has a top flat intensity distribution with an infrared sensor.

  Once the one-to-one correspondence between the irradiation shape and the intensity distribution of the reference laser beam 6 and the heating laser beam 3 can be confirmed, the irradiation light shape and the irradiation light intensity distribution of the reference laser beam 6 can be obtained from the next. By observing, the irradiation position and irradiation intensity of the heating laser beam 3 can also be confirmed. That is, observation of the heating laser beam 3 with a two-dimensional infrared sensor can be omitted. Therefore, the adjustment of the five irradiation heads accompanying the change of the substantially rectangular shape can be greatly reduced. The top flat irradiation light intensity distribution from the five directions thus obtained realizes high uniformity of the heating temperature distribution in the circumferential direction of the raw material rod 1. As a result, high stability of the irradiation temperature can be ensured.

  FIG. 8 shows an example of the configuration of the laser beam splitter 130 used in the first embodiment. The laser beam splitting device 130 of this example splits the semiconductor laser beam 5 emitted from the semiconductor laser device 120 into a plurality of beams. The laser beam splitting device 130 includes a Y-direction collimator 131, an X-direction collimator 132, an attenuation mirror 134, a first condenser lens 136, a second condenser lens 137, and a half mirror 139.

  The laser beam splitting device 130 makes the semiconductor laser beam 5 emitted from the semiconductor laser device 120 enter the Y-direction collimator 131 and the X-direction collimator 132. The Y direction collimator 131 and the X direction collimator 132 convert the semiconductor laser beam 5 into parallel laser beams.

  The half mirror 139 divides the parallel semiconductor laser light 5 converted by the Y direction collimator 131 and the X direction collimator 132 into M pieces. The half mirror 139 has a reflective film having a multilayer structure. Thereby, the half mirror 139 bends a part of the incident semiconductor laser light 5 in a predetermined direction and transmits the other part. The half mirror 139 is arranged so that the vertical axis of the half mirror 139 forms 45 degrees with respect to the traveling direction of the incident semiconductor laser beam 5. The half mirror 139 bends the semiconductor laser light 5 by 90 degrees to the left with respect to the traveling direction. The half mirror 139 of this example includes half mirrors 139a, 139b, 139c, 139d, and 139e. The reflectivities of the half mirrors 139a, 139b, 139c, 139d, and 139e are 15%, 18.4%, 23.5%, 32.8%, and 54% from the half mirror 139 close to the semiconductor laser device 120, respectively. .

  The loss of each half mirror 139 in this example is 3%. In this case, the semiconductor laser beam 5 having substantially the same reflection intensity within 15 ± 0.1% is obtained as the reflection intensity of the semiconductor laser beam 5 divided into five.

  The attenuation mirror 134 adjusts the reflection intensity of the five semiconductor laser beams 5 reflected by the half mirror 139. The attenuation mirror 134 is arranged so that the vertical axis of the attenuation mirror 134 forms 45 degrees with respect to the traveling direction of the semiconductor laser light 5 from the half mirror 139. Thereby, the attenuation mirror 134 reflects at least a part of the semiconductor laser light 5 to a damper or the like, and attenuates the irradiation intensity of the semiconductor laser light 5. The attenuation mirror 134 may include a mechanism such as an actuator in order to move without changing the angle between the M semiconductor laser beams 5 incident thereon and the vertical axis of the attenuation mirror 134. When the attenuation mirror 134 includes an actuator, the attenuation factor of each of the M semiconductor laser beams 5 divided can be freely adjusted. Therefore, the laser beam intensity of the M semiconductor laser beams 5 divided can be controlled to be uniform. The attenuation mirror 134 of this example includes attenuation mirrors 134a, 134b, 134c, 134d, and 134e corresponding to the half mirrors 139a, 139b, 139c, 139d, and 139e.

  The first condenser lens 136 and the second condenser lens 137 collect the semiconductor laser light 5 attenuated by the attenuation mirror 134 and make it incident on the fibers 31, 32, 33, 34, and 35. The lens that condenses the semiconductor laser beam 5 on the fibers 31, 32, 33, 34, and 35 is composed of a first condensing lens 136 and a second condensing lens 137 that are the minimum number of two condensing lenses. However, a combination of more condensing lenses may be used.

  The laser beam splitting device 130 is configured by the half mirror 139, but may be configured by a reflection mirror. Further, the laser beam splitting device 130 may use a prism-shaped reflection mirror. The laser beam splitting device 130 may use a split fiber that splits incident light. Further, the laser beam splitter 130 may be a laser beam splitter that combines these components. The reference laser beam 6 in the first embodiment is split into M reference laser beams 6 using a laser beam splitter 130. The reference light laser device 150 makes the reference laser light 6 enter the optical path integration unit 155. For example, the reference light laser device 150 is a laser device such as a YAG laser or a He—Ne laser.

  The optical path integration unit 155 is disposed on the optical paths of the semiconductor laser light 5 and the reference laser light 6. The optical path integrating unit 155 passes the incident semiconductor laser beam 5 and enters the laser beam splitting device 130. The optical path integration unit 155 reflects the reference laser light 6 so as to have the same optical path as the semiconductor laser light 5. The optical path integration unit 155 may be arranged to reflect the semiconductor laser light 5 and allow the reference laser light 6 to pass therethrough. The optical path integration unit 155 of this example uses a half mirror as an example, but the optical paths of the semiconductor laser light 5 and the reference laser light 6 can be integrated even if other optical systems are used.

  The reference laser beam 6 is split into M reference laser beams 6 by a laser beam splitting device 130 and is incident on M fibers. The reference laser beam 6 is shaped by a fiber and becomes a substantially square shape. Further, the reference laser beam 6 is irradiated to the raw material rod 1 in the same irradiation beam shape as the semiconductor laser beam 5 by M irradiation heads. The irradiation position and intensity distribution of the reference laser beam 6 may be confirmed using a cardboard for observation instead of the raw material bar 1 or a white bar.

  Further, long-term temperature fluctuation is controlled by the output control unit 70 from the temperature measuring unit 50 of the melting zone 4. The output control unit 70 outputs a control signal based on the PID method, and controls the output of one laser power source 110. The output control unit 70 can freely adjust the temperature sensitivity by adopting the PID method. PID control has a function to determine optimum sensitivity and response speed by itself. Switching between manual control mode and automatic control mode is easy. The reproducibility of the temperature measured by the temperature measuring unit 50 is realized within ± 0.2 ° C. High reproducibility of the temperature measured by the temperature measuring unit 50 is important for accurately controlling the temperature of the melting zone 4. FIG. 4 shows that the single crystal growth apparatus 100 according to Example 1 can be controlled so that the temperature of the region within 2 mmφ at the center of the melting zone 4 is within ± 1 ° C. over several hours.

  In the method for producing a floating melt zone crystal using light irradiation, it is extremely important for crystal production that the light irradiation intensity can be controlled while monitoring the melting zone temperature during crystal production. In the conventional method for producing a floating melting zone crystal using a confocal ellipsoid using a halogen lamp, the confocal ellipsoidal reflector 530 surrounds the periphery, and thus the melting zone temperature cannot be observed (see FIG. 30). The molten zone state means that the width of the molten zone decreases or increases, the molten zone state fluctuates left and right and becomes unstable. In addition, the melting zone temperature is also lowered because the rotation of the raw material rod 1 becomes discontinuous. Such a phenomenon is not observed until the lower limit or near the upper limit of the temperature region where the melting zone 4 is stabilized. Since the single crystal growth apparatus 100 of this example can detect the melting zone temperature with a temperature accuracy within ± 0.2 ° C., it is a sensitive detection method that can detect the state of the melting zone 4 before the melting zone 4 becomes unstable. I will provide a.

  According to the first embodiment, with respect to a new laser heating method using a semiconductor laser light source, a method of measuring radiated light and controlling it by the measurement output has not been known. Since a large number of semiconductor laser power sources such as 5 or 7 had to be controlled at the same time, the difficulty in controlling the measurement output was also expected. In the first embodiment having the laser beam splitting device 130, it is only necessary to control one laser power source 110, so the heating laser beams 3 from the five laser irradiation heads are simultaneously controlled by a highly accurate control method such as the PID method. It has become possible. The output control unit 70 of the melting zone 4 is output for control. The result can be easily stored as a temperature history in a recorder. Since the temperature of the melting zone 4 is unstable at the initial stage of crystal growth, the semiconductor laser power output is manually controlled while monitoring the temperature of the melting zone 4. Since there is one laser power source 110, it is possible to easily control the irradiation intensity of the heating laser beam 3 from five irradiation heads simultaneously. After that, it switches to automatic control at a relatively stable stage. In the automatic control method, a PID control method may be used. The output control unit 70 controls the laser power supply 110 so that the temperature of the melting zone 4 is kept constant during the growth time of several days to several weeks. In automatic control operation, it is important to set an upper temperature limit. For some reason, dripping of the melt zone 4 may occur and the dripping may occur. In such a case, it is important to determine that the temperature has suddenly decreased, and to have an emergency shut-off process that does not increase the output of the laser power supply 110 in order to increase the irradiation intensity of the semiconductor laser light 5.

  As can be seen from the above examples, the single crystal growing apparatus 100 accurately measures the temperature of a small region of 2 mmφ at the center of the melting zone 4 during heating of the raw material rod 1. That is, the single crystal growing apparatus 100 can accurately heat the melting zone 4 to a desired temperature shown in the crystal phase diagram. In particular, the effect is high when using a solvent moving floating zone (TSFZ) method.

  The TSFZ method is a crystal production method using a flux material having a component different from that of a crystal to be grown. The crystal growth rate by the TSFZ method is about 0.5 mm per unit time. Therefore, in the TSFZ method, it takes about 200 hours (about 9 days) to grow a 10 cm crystal. The single crystal growing apparatus 100 can determine the flux component concentration of the melting zone 4 during crystal growth by knowing the stable temperature of the melting zone 4. For example, in the single crystal growing apparatus 100, if the temperature of the melting zone 4 is increased, it can be seen that the flux concentration of the melting zone 4 is biased to one side. From the deviation of the flux concentration in the melting zone 4, the growth continuation time can be estimated. Estimation of the growth continuation time is particularly important in a crystal growth method that requires a long growth time, such as the TSFZ method. Further, the flux concentration can be adjusted in advance based on the deviation of the flux concentration in the melting zone 4. Once the relationship between the melting zone composition and the melting temperature is known, an appropriate melting zone temperature can be determined. Crystal growth over several days can be stably maintained by controlling the intensity of the heating laser beam 3 based on the temperature actually measured so as to maintain the melting temperature.

  Moreover, the single crystal growing apparatus 100 can know the melting point of the raw material rod 1 immediately before the melting temperature by actually measuring the temperature of the melting zone 4 during heating. In order for the raw material rod 1 to melt, melting heat is required. Therefore, even if the intensity of the heating laser beam 3 is gradually increased, a temperature region is generated in which the temperature of the raw material rod 1 does not increase accordingly. Since the single crystal growing apparatus 100 can detect the actual temperature of the raw material rod 1, it can grasp the melting heat phenomenon of the raw material rod 1. Since it is known in advance that the single crystal growing apparatus 100 is heated to a temperature close to the melting temperature of the raw material rod 1, the intensity of the heating laser beam 3 may be carefully controlled at the stage where the raw material rod 1 is melted. It is important to grasp the melting heat phenomenon of the raw material rod 1 in order to accurately grasp the melting point temperature of a new material or an unknown material. That is, the single crystal growth apparatus 100 can melt the raw material rod 1 and grow a single crystal at an arbitrary temperature even when the temperature of the crystal phase diagram is inaccurate.

[Example 2]
FIG. 9 shows the relationship between the temperature (degree) of the raw material rod 1 and the irradiation light intensity (W). The single crystal growing apparatus 100 of this example heats the raw material rod 1 by five laser irradiation heads 21, 22, 23, 24 and 25. The material of the raw material rod 1 is PrCaMnO ₃ (PCMO), and is a black material having a melting point temperature of 2000 ° C. or higher. The wavelength of the heating laser beam 3 is 940 nm.

  The irradiation light intensity is determined according to the heating temperature of the raw material rod 1 and the size of the irradiation light shape. From the measurement result of this example, when the irradiation light shape is 4 mm × 8 mm, the intensity of irradiation light of 10 W or more is required per unit to heat the raw material rod 1 to 1000 ° C. In order to heat the raw material rod 1 to 1500 ° C., an irradiation light intensity of 25 W or more per unit is required. In order to heat the raw material rod 1 to 2000 ° C. or higher, an irradiation light intensity of 70 W or more per unit is required. From the above, in order to heat the black material rod 1 to a temperature of about 2000 ° C., an irradiation light intensity of 70 W or more per unit is required when the irradiation light shape is 4 mm × 8 mm.

With a material generally used for the raw material rod 1, heating to about 2000 ° C. is sufficient for growing a single crystal. Therefore, in the case where the single crystal growing apparatus 100 uses five irradiation lights, 70 W or more per unit is sufficient for heating and melting the black body material. In addition, if the irradiation light area is large, the heating laser beam 3 with a larger output is required. Therefore, in order to heat the raw material rod 1 to 2000 ° C. or higher, the output of the heating laser beam 3 of 2.2 W / mm ² or more in unit area is required.

[Example 3]
10A to 10D show a configuration example of the laser irradiation head 21. FIG. 10A to 10D, the irradiation light shape and the size of the heating laser light 3 irradiated by the laser irradiation head 21 are different from each other. However, the respective laser irradiation heads 21 may use common fixing jigs d1 and d2. FIG. 10B shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 4 mm × 8 mm. FIG. 10B is the same as the laser irradiation head 21 shown in FIG. In addition, the irradiation light shape of the heating laser beam 3 may have a width of the irradiation light shape of 7 mm or more and less than 20 mm and a height of 3 mm or more and less than 20 mm.

  FIG. 10A shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 3 mm × 8 mm. The laser condensing unit 27 of this example includes a cylindrical lens having a focal length smaller than that of the vertical cylindrical lens in the laser condensing unit 27 of the first embodiment. Thereby, the irradiation light shape of this example is reduced from 4 mm to 3 mm in height with respect to the first embodiment.

  FIG. 11 shows a result of actual measurement using a two-dimensional infrared sensor of the intensity of the substantially square irradiation light of 3 mm × 8 mm. The irradiation intensity C of the heating laser beam 3 indicates the intensity distribution in the width direction of the heating laser beam 3 at the broken line c. On the other hand, the irradiation intensity D of the heating laser beam 3 indicates the intensity distribution in the height direction of the heating laser beam 3 at the broken line d. The measurement result of this example shows that the heating laser beam 3 has an irradiation light shape of 3 mm × 8 mm and has a top flat irradiation intensity distribution. The variation of the irradiation light intensity on the upper side of the trapezoidal intensity distribution is within ± 5% of the irradiation light intensity.

[Example 4]
FIG. 10C shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 10 mm × 10 mm. In this example, the height and width of the irradiation light shape are equal. The laser condensing unit 27 can easily realize a square irradiation light shape using a convex lens. Also in this case, the laser condensing unit 27 is fixed by the fixing jig d2.

  FIG. 12 shows the result of actual measurement using a two-dimensional infrared sensor of the intensity of the substantially square irradiation light of 10 mm × 10 mm. The irradiation intensity E of the heating laser beam 3 indicates the intensity distribution in the width direction of the heating laser beam 3 at the broken line e. On the other hand, the irradiation intensity F of the heating laser beam 3 indicates the intensity distribution in the height direction of the heating laser beam 3 along the broken line f. The measurement result of this example shows that the heating laser beam 3 has an irradiation light shape of 10 mm × 10 mm and has a top flat irradiation intensity distribution. The variation in the irradiation light intensity of the top is within ± 5% of the irradiation light intensity. The laser irradiation head 21 of this example is used when the diameter of the raw material rod 1 is relatively thick, such as about 8 mm. Here, when the raw material rod 1 becomes large, it is often necessary to increase the length of the melting zone 4. Further, when the diameter of the raw material rod 1 is increased, the solid phase of the raw material rod 1 and the crystal rod 2 may collide. Therefore, in the irradiation light shape of this example, in addition to increasing the width to 10 mm, the height is also increased to 10 mm.

[Example 5]
FIG. 10D shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 15 mm × 15 mm. As in the case of the third embodiment, the laser condensing unit 27 of this example can easily realize a square irradiation light shape using a convex lens. Also in this case, the laser condensing unit 27 is fixed by the fixing jig d2.

  FIG. 13 shows the result of actual measurement using a two-dimensional infrared sensor of the intensity of the substantially square irradiation light of 15 mm × 15 mm. The irradiation intensity G of the heating laser beam 3 indicates the intensity distribution in the width direction of the heating laser beam 3 along the broken line g. On the other hand, the irradiation intensity H of the heating laser beam 3 indicates the intensity distribution in the height direction of the heating laser beam 3 at the broken line h. The measurement result of this example shows that the heating laser beam 3 has an irradiation light shape of 15 mm × 15 mm and has a top flat irradiation intensity distribution. The variation in the irradiation light intensity of the top is within ± 5% of the irradiation light intensity. The laser irradiation head 21 of this example can cope with a case where the diameter of the raw material rod 1 is larger than that of the third embodiment.

[Example 6]
14A to 14C show a configuration example of the laser irradiation head 21. FIG. The laser irradiation head 21 of this example has an exit side lens 28, and changes the height while keeping the width of the irradiation light shape constant. FIG. 14A shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 3 mm × 10 mm. FIG. 14B shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 5 mm × 10 mm. FIG. 14C shows a configuration example of the laser irradiation head 21 that generates an irradiation light shape of 10 mm × 10 mm.

  The exit side lens 28 generates the heating laser light 3 having an arbitrary irradiation light shape based on the semiconductor laser light from the fiber 31. The exit side lens 28 moves back and forth with respect to the traveling direction of the heating laser beam 3 in the laser condensing unit 27. The exit lens 28 is moved by an actuator or the like provided in the laser irradiation head 21. Thereby, the laser irradiation head 21 changes the height while keeping the width of the irradiation light shape of the heating laser light 3 constant. For example, the laser irradiation head 21 sets the irradiation light shape to 3 mm × 10 mm by setting the distance from the exit side lens 28 to the position of the irradiation light shape as Da. Further, the laser irradiation head 21 sets the irradiation light shape to 5 mm × 10 mm by setting the distance from the exit side lens 28 to the position of the irradiation light shape as Db. Further, the laser irradiation head 21 sets the irradiation light shape to 10 mm × 10 mm by setting the distance from the exit side lens 28 to the position of the irradiation light shape as Dc. Da, Db, and Dc in this example have a relationship of Da <Db <Dc. Although the case where the width of the irradiation light shape is 10 mm has been described here, the height can be changed by fixing the width of the irradiation light shape similarly when the width of the irradiation light shape is 8 mm or 15 mm. The laser condensing unit 27 has a gear having a rotation mechanism for controlling the lens position, and may be controlled by a pulse motor from the outside. Thereby, the single crystal growing apparatus 100 can control the irradiation light shape while irradiating the heating laser beam 3 based on the state of the melting zone 4 and the irradiation temperature.

  As described above, the laser irradiation head 21 freely changes the size of the irradiation light shape of the heating laser light 3 by adjusting the position of the exit side lens 28. Further, the size of the irradiation light shape of the heating laser beam 3 is an index for controlling the temperature of the melting zone 4. That is, the laser irradiation head 21 can control the temperature of the melting zone 4 by freely changing the irradiation intensity of the heating laser light 3.

[Example 7]
FIG. 15 shows a configuration example of the single crystal growing apparatus 100 according to the seventh embodiment. The single crystal growing apparatus 100 of this example further includes an illumination unit 60.

  The illumination unit 60 irradiates the raw material rod 1 and the crystal rod 2 near the melting zone 4 with illumination light. For example, the illumination light is light from a halogen lamp or a semiconductor diode. The arrangement position of the illumination part 60 should just be a position which does not disturb the optical path of the heating laser beam 3 irradiated to the raw material stick | rod 1. FIG. The illumination unit 60 of this example is disposed between the laser irradiation head 22 and the damper 42. On the other hand, in the conventional single crystal growing apparatus using the confocal ellipsoidal reflector, the confocal ellipsoidal reflector is arranged on the left and right of the raw material rod 1, so that the illumination unit 60 cannot be arranged in the vicinity of the raw material rod 1. .

  FIG. 16A shows a photograph of the vicinity of the melting zone 4 when there is no irradiation light when the raw material rod 1 is heated. Since the molten zone 4 emits light by heating, it can be observed without illumination light. However, the raw material rod 1 and the crystal rod 2 above and below the melting zone 4 are dark and cannot be observed. Further, when the light emitted from the melting zone 4 is strong, it is necessary to protect the camera sensor by increasing the aperture of the observation camera. As a result, the observation image of the raw material rod 1 during crystal growth or the grown single crystal becomes dark and cannot be observed.

  FIG. 16B is a photograph of the vicinity of the melting zone 4 when irradiated with high-intensity diode light. In this example, the high intensity diode light is irradiated from the illumination unit 60 to the raw material rod 1 and the crystal rod 2 in the vicinity of the melting zone 4. Since the emission intensity of the melting zone 4 is strong, high-intensity diode illumination may be used. Thereby, even if the melting zone 4 is in a high temperature state, the sensor of the camera can be protected and the vicinity of the melting zone 4 can be observed. By observing the vicinity of the melting zone 4, the crystal plane of the grown single crystal can be observed.

  The observation photograph of the crystal plane shows that the raw material rod 1 is single-crystallized by heating. When the crystal plane is not observed, there is a high possibility that the raw material rod 1 is not single-crystallized by heating. Further, when the crystal plane grows in an oblique direction or has a plane where the crystal planes intersect, a crystal having a twin structure is grown instead of a single crystal. In this case, the single crystal growing apparatus 100 needs to perform a necking process or the like in which the radius of the melting zone 4 is once reduced to narrow the diameter of the grown crystal. Depending on the crystal plane, multiple necking processes may be required. Therefore, it is important to confirm that the growth surface of the single crystal grows regularly after the raw material rod 1 is heated.

[Example 8]
FIG. 17 is a photograph of a Y-type ferrite single crystal rod having the chemical formula A ₂ B ₂ C ₁₂ O ₂₂ . A Y-type ferrite single crystal rod of chemical formula A ₂ B ₂ C ₁₂ O ₂₂ is grown by a single crystal growth apparatus 100 having five laser irradiation heads. The growth conditions in this example are under 9.9 atmospheres of oxygen as in Example 1. The growth rate is 1 mm per hour.

In the Y-type ferrite single crystal rod of the chemical formula A ₂ B ₂ C ₁₂ O ₂₂ , A contains at least one of Ba, Sr, Sc, and Pb elements. B contains at least one of Co, Zn, Cu, Cd, Ni, and Mg elements. C contains Fe, the main component, and Al, Ga, or Mn element. The single crystal rod in the photograph has the chemical formula (Ba _1-x Sr _x ) ₂ Co ₂ Fe _12-y Al _y O ₂₂ , 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, and x = 0.5, y = This is the case of 1. A cleaved surface is observed at the right end of the single crystal bar, indicating that the single crystal bar is a good quality crystal.

  The Y-type ferrite material of this example decomposes near the melting point. In a single crystal growth apparatus using a halogen lamp, the temperature of the interface between the melting zone 4 and the single crystal cannot be distinguished, and therefore a Y-type ferrite single crystal cannot be grown. On the other hand, the single crystal growing apparatus 100 using the heating laser beam 3 can distinguish the temperature at the interface between the melting zone 4 and the single crystal. In the melting zone 4, even if the decomposition solution has a different crystal composition, if there is a desired crystal phase in the lower part, it can be epitaxially grown with the same crystal composition as the lower crystal composition. Thereby, the single crystal growing apparatus 100 realizes growth of a large Y-type ferrite single crystal by a floating melting zone method.

[Example 9]
FIG. 18 is a photograph of a W-type ferrite single crystal rod having the chemical formula AB ₂ C ₁₆ O ₂₇ . A W-type ferrite single crystal rod of chemical formula AB ₂ C ₁₆ O ₂₇ is grown by a single crystal growth apparatus 100 having five laser irradiation heads. The growth conditions are under 9.9 atmospheres of oxygen as in Example 1. The growth rate is 1 mm per hour.

In the W-type ferrite single crystal rod of the chemical formula AB ₂ C ₁₆ O ₂₇ , A contains at least one of Ba, Sr, Sc, and Pb elements. B contains at least one of Co, Zn, Cu, Cd, Ni, and Mg elements. C contains Fe, the main component, and Al, Ga, or Mn element. The single crystal bar in the photograph is a case where the chemical formula Ba _1-x Sr _x Co ₂ Fe _16-y Al _y O ₂₂ , 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, and x = 0 and y = 0. The strong reflected light on the surface of the single crystal rod indicates a specific crystal plane in a mirror state where the crystal side surface is excellent. This indicates that a crystal having such a beautiful reflecting surface is a high-quality single crystal.

  The W-type ferrite material of this example decomposes near the melting point. In a single crystal growing apparatus using a halogen lamp, the temperature of the interface between the melting zone 4 and the single crystal cannot be distinguished, and thus a W-type ferrite single crystal cannot be grown. On the other hand, the single crystal growing apparatus 100 using the heating laser beam 3 can distinguish the temperature at the interface between the melting zone 4 and the single crystal. In the melting zone 4, even if the decomposition solution has a different crystal composition, if there is a desired crystal phase in the lower part, it can be epitaxially grown with the same crystal composition as the lower crystal composition. Thereby, the single crystal growth apparatus 100 realizes growth of a large W-type ferrite single crystal by a floating melting zone method.

[Example 10]
FIG. 19 is a photograph of a Z-type ferrite single crystal rod having the chemical formula A ₃ B ₂ C ₂₄ O ₄₁ . A Z-type ferrite single crystal rod of the chemical formula A ₃ B ₂ C ₂₄ O ₄₁ is grown by a single crystal growing apparatus 100 having five laser irradiation heads. The growth conditions are under 9.9 atmospheres of oxygen as in Example 1. The growth rate is 1 mm per hour.

In the Z-type ferrite single crystal rod of the chemical formula A ₃ B ₂ C ₂₄ O ₄₁ , A contains at least one of Ba, Sr, Sc, and Pb elements. B contains at least one of Co, Zn, Cu, Cd, Ni, and Mg elements. C contains Fe, the main component, and Al, Ga, or Mn element. The single crystal rod in the photograph is represented by the chemical formula (Ba _1-x Sr _x ) ₃ Co ₂ Fe _24-y Al _y O ₄₁ , 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, and x = 0 and y = 0 It is. The right end of the single crystal bar shows a clean cleavage plane, indicating that a high quality single crystal is obtained.

  The Z-type ferrite material of this example decomposes near the melting point. In a single crystal growth apparatus using a halogen lamp, the temperature at the interface between the melting zone 4 and the single crystal cannot be distinguished, and thus a Z-type ferrite single crystal cannot be grown. On the other hand, the single crystal growing apparatus 100 using the heating laser beam 3 can distinguish the temperature at the interface between the melting zone 4 and the single crystal. In the melting zone 4, even if the decomposition solution has a different crystal composition, if there is a desired crystal phase in the lower part, it can be epitaxially grown with the same crystal composition as the lower crystal composition. Thereby, the single crystal growing apparatus 100 realizes growth of a large Z-type ferrite single crystal by a floating melting zone method.

  Examples 8 to 10 demonstrate that, when the heating laser beam 3 is used as an irradiation light source, a large single crystal can be obtained even in a material in which the melt is decomposed and melted. This is because heating the raw material rod 1 using the heating laser beam 3 enables heating with a sharp temperature gradient at the interface between the melting zone 4 and the single crystal. That is, the melt does not cover the single crystal surface. Therefore, the single crystal growing apparatus 100 of this example can grow single crystal rods of Y-type, W-type, and Z-type ferrite materials by forming a sharp temperature gradient at the interface between the melting zone 4 and the single crystal. Regarding other materials, the single crystal growing apparatus 100 has the potential to grow single crystals of materials that could not be grown by the conventional single crystal growing apparatus using the confocal ellipsoidal reflector.

  FIG. 20 shows an example of the configuration of the melting zone monitoring unit 54. 21A and 21B show more detailed views of the polarizer rotating device 56. FIG. The polarizer rotating device 56 of this example includes a fixed polarizer 57, a rotating polarizer 58, and a polarizer rotating unit 59.

  The fixed polarizer 57 is arranged with the polarization axis with respect to the camera 55 fixed. On the other hand, the rotating polarizer 58 can rotate the polarization axis with respect to the camera 55 by the polarizer rotating unit 59. The polarizer rotating unit 59 may include a mechanism for rotating the rotating polarizer 58 such as an actuator. For example, the polarizer rotating unit 59 rotates the polarization axis of the rotating polarizer 58 according to a polarizer rotating pulse input from the outside. More specifically, the polarizer rotating unit 59 crosses the polarization direction of the fixed polarizer 57 and the polarization direction of the rotating polarizer 58 to make the transmittance of the heating laser light 3 zero. The polarizer rotating unit 59 can adjust the transmittance of the heating laser light 3 by gradually rotating the polarization direction of the rotating polarizer 58.

  FIG. 22 shows an example of the configuration of the laser irradiation head 21. The laser irradiation head 21 includes a reflecting mirror 29.

  The reflecting mirror 29 is a reflecting mirror that heats the crystal rod 2 by reflecting the heating laser beam 3. For example, the reflecting mirror 29 is a concave mirror that spreads the heating laser beam 3. The heating range of the crystal rod 2 can be expanded by rotating the concave mirror. That is, by expanding the irradiation range of the heating laser beam 3 using the reflecting mirror 29, the steep temperature gradient between the melting zone 4 and the crystal rod region can be relaxed. As a result, the crystal rod 2 is difficult to crack. Therefore, the single crystal growing apparatus 100 is effective when the material of the crystal rod 2 is a material that easily cracks. However, when the reflecting mirror 29 is used, the temperature of the melting zone 4 is lower than when the reflecting mirror 29 is not used. Therefore, the single crystal growing apparatus 100 may adjust the rotation angle of the reflecting mirror 29 according to the material of the raw material rod 1 to be used. Further, the single crystal growing apparatus 100 may have a mechanism for adjusting the angle of the reflecting mirror 29 during irradiation with the heating laser beam 3.

  FIG. 23 shows an example of the configuration of the laser irradiation head 21. The laser irradiation head 21 includes an exit side lens 28.

  The exit side lens 28 is configured by a concave cylindrical lens. The exit side lens 28 expands the incident heating laser beam 3. The exit side lens 28 converts the top flat irradiation light intensity distribution into a bell-shaped intensity distribution.

  The bell-shaped intensity distribution is a Gaussian-shaped irradiation light intensity distribution having a peak near the center of the irradiation light shape. That is, the bell-shaped intensity distribution is an intensity distribution obtained by relaxing the steep top flat intensity distribution. In the bell-shaped intensity distribution, cracks are less likely to occur in the crystal rod 2 by relaxing the irradiation light intensity distribution. Therefore, the single crystal growth apparatus 100 may use the exit side lens 28 of this example when the material of the crystal rod 2 is a material that easily cracks.

  FIG. 24 shows an example of the configuration of the single crystal growing apparatus 100 including the auxiliary heating unit 80. FIG. 25 shows an example of a top view of the auxiliary heating unit 80.

  The auxiliary heating unit 80 auxiliaryly heats the area near the melting zone 4. The auxiliary heating unit 80 includes a pair of halogen lamps 81 and a reflecting mirror 82 disposed with the raw material rod 1 interposed therebetween. The auxiliary heating unit 80 arranges the halogen lamp 81 at the focal position of the reflecting mirror 82. The reflecting mirror 82 irradiates the raw material rod 1 with infrared rays emitted from the halogen lamp 81. For example, the auxiliary heating unit 80 can easily heat the temperature of the raw material rod 1 to 1000 ° C. or more by irradiating the vicinity of the melting zone 4 with infrared rays. Thereby, even if the single crystal growing apparatus 100 of this example is a material which is easy to generate | occur | produce the crack by a thermal strain, it can obtain a crack-free single crystal rod. The auxiliary heating unit 80 may include a plurality of sets of halogen lamps 81 and reflecting mirrors 82 arranged with the raw material rod 1 interposed therebetween.

  FIG. 26 shows an example of the temperature in the vicinity of the melting zone 4. The horizontal axis indicates the position (mm) in the height direction of the melting zone 4, and the vertical axis indicates the temperature (° C.) of the melting zone 4. The single crystal growing apparatus 100 of this example uses the auxiliary heating unit 80 to uniformly control the temperature of the melting zone 4.

  The center (0 mm) of the measurement position indicates the center position of the melt zone 4 in the height direction. The temperature at the center position of the melting zone 4 exceeds 1000 ° C. Further, the temperature of the melting zone 4 linearly decreases as the center of the melting zone 4 reaches the maximum temperature and moves away from the center of the melting zone 4. The temperature distribution of the melting zone 4 is preferably a bell distribution as shown in FIG. In this example, the infrared rays from the auxiliary heating unit 80 are irradiated in a range of ± 10 mm from the center of the melting zone 4.

  FIG. 27 shows an example of the configuration of the single crystal growing apparatus 100 including the auxiliary heating unit 80. The auxiliary heating unit 80 of this example includes a pair of linear lamps 83 and a concave mirror 84. The auxiliary heating unit 80 may include a plurality of sets of linear lamps 83 and concave mirrors 84.

  The linear lamp 83 has a plurality of halogen lamps and irradiates infrared rays with uniform intensity. The linear lamp 83 is disposed at the focal position of the concave mirror 84. The linear lamp 83 in this example uses a halogen lamp, but may be a mercury lamp.

  The concave mirror 84 reflects the infrared rays emitted from the linear lamp 83 to the raw material rod 1 linearly. Reflecting linearly means reflecting the infrared rays emitted from the linear lamp 83 uniformly in the height direction of the raw material rod 1. The concave mirror 84 has a linear focal point on the central axis of the raw material rod 1 and has a concave mirror shape on a surface perpendicular to the central axis of the raw material rod 1. The shape of the concave mirror 84 may be a semi-cylindrical shape.

  The auxiliary heating part 80 of this example can expand the area | region which irradiates infrared rays to the raw material stick | rod 1 rather than the case shown in FIG. The auxiliary heating unit 80 in this example heats the region closer to the crystal rod 2 than the melting zone 4. The irradiation region of the auxiliary heating unit 80 may be in the range of 0 to 10 cm or more from the center of the melting zone 4 of the raw material rod 1. Thereby, the auxiliary | assistant heating part 80 of this example can further reduce the crack by heat strain, heating the temperature of the raw material stick | rod 1 to 1000 degreeC or more. Note that the auxiliary heating unit 80 may heat the region closer to the raw material rod 1 than the melting zone 4.

  FIG. 28 shows a configuration example of a single crystal growth apparatus 100 including a magnetic field application unit. The magnetic field application unit of this example includes a coil C and a DC power supply 90.

  The coil C generates a magnetic field in the coil C according to the direct current from the DC power supply 90. The coil C is disposed so that the raw material rod 1 and the crystal rod 2 are included in the coil C. However, the position of the coil C is adjusted so that the heating laser beam 3 does not irradiate the coil C. Thereby, a magnetic field can be applied to the raw material rod 1, the melting zone 4, and the single crystal part. The magnetic field generated in the coil C has a convection effect on the melting zone 4. Moreover, the single crystal growing apparatus 100 of this example can be used for controlling the magnetic moment of an element when growing a single crystal having magnetism. For example, the magnetic moment is aligned in one direction by applying a magnetic material at a high temperature. Thereafter, even if the crystal rod is cooled, a single crystal rod having a magnetic moment aligned in a predetermined direction can be obtained. As described above, the single crystal growing apparatus 100 can manufacture a magnetic crystal having a new magnetic phase by combining the application of a magnetic field and the floating melting zone method at high temperature.

  FIG. 29 shows a configuration example of a single crystal growth apparatus 100 including a high frequency application unit. The magnetic field application unit of this example includes a coil C and an AC power source 95.

  The coil C applies a high frequency in the coil C according to the alternating current from the AC power source 95. The coil C is disposed so that the raw material rod 1 and the crystal rod 2 are included in the coil C. However, the position of the coil C is adjusted so that the heating laser beam 3 does not irradiate the coil C. Thereby, a high frequency can be applied to the raw material rod 1, the melting zone 4, and the single crystal part.

  In the application of the high frequency, the high frequency itself vibrates the electrons in the raw material rod 1 to directly heat the raw material rod 1. Particularly, when the material of the raw material rod 1 is a metal material, the effect of heating by high frequency is remarkable. Thereby, the single crystal growing apparatus 100 of this example can control the temperature separately from the heating by the heating laser beam 3 while strictly distinguishing the temperature states of the raw material rod 1 and the melting zone 4. Since the single crystal growth apparatus 100 of this example has high controllability of temperature, it can perform a physical analysis in detail regarding the growth of a metal single crystal. Detailed physical analysis is particularly useful for materials with complex alloy phases.

The single crystal growth apparatus 100 using the laser beam disclosed in this specification has the following characteristics.
1. The single crystal growth apparatus 100 includes a laser power source, a heating laser light source, and a laser beam splitting device that divides the laser beam into M pieces of irradiation light. The irradiation light which has is irradiated. Furthermore, it has one reference laser light source, is divided into M reference laser beams by a laser splitting device in the same manner as the heating laser, and has the same substantially square shape and irradiation light intensity distribution as the heating laser from the M irradiation heads Irradiate light. The substantially rectangular shape of the heating laser and the irradiation light intensity distribution can be easily and safely adjusted with the reference laser light in the visible region.
2. The single crystal growth apparatus 100 is composed of one laser power source, one laser light source, and a laser beam splitter that divides the laser beam into M pieces of irradiation light, and has a substantially square shape irradiation light intensity distribution from the M irradiation heads. Irradiation light is irradiated, the heating part of the raw material rod 1 directly measured by the temperature measuring unit 50, the temperature of the melting zone 4 and the like are fed back, the output control unit 70 controls the output of one laser power source, and the raw material The heating temperature of the rod 1 is controlled. That is, the single crystal growing apparatus 100 can easily set the temperature of the melting zone 4 to a desired temperature, and can control the heating temperature stably for a long time with high accuracy.
3. The single crystal growing apparatus 100 can freely control the substantially rectangular irradiation shape and irradiation light intensity distribution from the top flat shape to the bell-shaped irradiation light intensity distribution according to the state and temperature of the melting zone 4.
4). The single crystal growth apparatus 100 can irradiate the high-intensity diode light for irradiation above and below the melting zone 4 and observe the raw material rod 1 and the surface of the single crystal close to the melting zone 4. Thereby, the single crystal growing apparatus 100 can observe the phenomenon of sucking the molten material into the raw material rod 1 and confirm the growth of the crystal plane of the crystal rod 2.
5. In the case of a material that is not suitable for rapid cooling of the temperature during the growth of the original crystal, the single crystal growing apparatus 100 can improve the crystallinity by heating the melting zone 4 of the raw material rod 1 with infrared rays from the outside.
6). The single crystal growing apparatus 100 can control the polarizer rotating apparatus 56 during single crystal growth without exposing the operator to laser light.
7). The single crystal growing apparatus 100 can arrange a coil wire for applying a magnetic field or a high frequency.

  As described above, the single crystal growing apparatus 100 can freely add a function necessary for controlling the single crystal rod in parallel with the heating of the raw material rod 1 by the heating laser beam 3. With such a configuration, the single crystal growing apparatus 100 can obtain Y-type, W-type, and Z-type ferrite crystals in which the raw material is decomposed and melted in the melting portion.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 1 ... Raw material rod, 2 ... Crystal rod, 3 ... Heating laser beam, 4 ... Melting zone, 5 ... Semiconductor laser beam, 6 ... Reference laser beam, 10 ... Quartz Tube: 11 ... Raw material rod holder, 12 ... Single crystal holder, 21 ... Laser irradiation head, 22 ... Laser irradiation head, 23 ... Laser irradiation head, 24 ... Laser irradiation Head, 25... Laser irradiation head, 26... Parallel light generation unit, 27... Laser condensing unit, 28. ... Fiber, 33 ... Fiber, 34 ... Fiber, 35 ... Fiber, 41 ... Damper, 42 ... Damper, 43 ... Damper, 44 ... Damper, 45 ... Damper, 50 ... temperature measuring unit, 51 ... lens, 52 ... filter, 53 ..Photodetector, 54... Melting zone monitoring unit, 55... Camera, 56... Polarizer rotating device, 57. Polarizer rotating unit, 60 ... illuminating unit, 70 ... output control unit, 80 ... auxiliary heating unit, 81 ... halogen lamp, 82 ... reflecting mirror, 83 ... linear lamp, 84 ... concave mirror, 90 ... DC power source, 95 ... AC power source, 100 ... single crystal growing device, 500 ... single crystal growing device, 501 ... raw material rod, 510 ... quartz Tube: 520 ... Halogen lamp, 530 ... Confocal ellipsoidal reflector, 110 ... Laser power supply, 120 ... Semiconductor laser device, 130 ... Laser beam splitting device, 131 ... Y direction Collimator 132 ... X direction collimator 134 ... Attenuating mirror 13 ... first condensing lens, 137 ... second condensing lens, 139 ... half mirror, 140 ... optical bench, 150 ... reference beam laser device, 155 ... optical path integration unit

Claims (32)

In a single crystal growth apparatus using M heating laser beams,
One semiconductor laser power supply;
One semiconductor laser device that emits one semiconductor laser beam based on the power supplied by the one semiconductor laser power source;
A laser beam splitting device for splitting the one semiconductor laser beam into M heating laser beams;
M laser irradiation heads that irradiate the raw material rods radially with the M heating laser beams in a substantially rectangular irradiation light shape around the central axis of the raw material rods;
One reference light laser device for irradiating the raw material bar with visible reference laser light;
An optical path integrating unit that guides the reference laser beam to the same optical path as the semiconductor laser beam to the laser beam splitter;
A temperature measuring unit for measuring the temperature of the raw material rod;
A single crystal growth apparatus comprising: an output control unit that controls output of the M heating laser beams based on a temperature of the raw material rod. The single crystal growing apparatus according to claim 1, wherein the temperature measuring unit optically measures the temperature of the raw material rod when the M heating laser beams are irradiated to the raw material rod. The temperature measuring unit is
A lens that collects the emitted light from the raw material rod;
A laser blocking unit that blocks irradiation of the M heating laser beams to the temperature measuring unit;
The single crystal growth apparatus according to claim 1, further comprising: a light intensity detector that detects the emitted light.   4. The single crystal growth apparatus according to claim 1, wherein the temperature measuring unit measures the temperature of at least a part of the irradiation region of the M heating laser beams in the raw material bar. 5. The single crystal growth apparatus according to claim 4, wherein the temperature measurement unit has a pinhole for limiting a range of a temperature measurement region . The output control unit controls the output of the M heating laser beams according to a temperature change of the raw material rod, and controls the irradiation intensity of the M heating laser beams. The single crystal growing apparatus according to one item. The single output unit according to any one of claims 1 to 6, wherein the output control unit controls an output of the M heating laser beams by a PID control method and controls an irradiation intensity of the M heating laser beams. Crystal growth device. The output control unit controls the irradiation intensity of the M heating laser beams so that the temperature of the raw material rod is equal to or lower than a predetermined temperature, and the temperature of the raw material rod exceeds a predetermined temperature. case, the single crystal growth apparatus according to any one of the M present claims 1 to 7 you cut off the output of the heating laser beam. 9. The M laser irradiation heads are arranged so as to irradiate M heating laser beams having a substantially rectangular irradiation light shape that is radial with respect to the central axis and at an equal interval. The single crystal growth apparatus as described in any one of Claims. The single crystal growing apparatus according to any one of claims 1 to 9, wherein the M laser irradiation heads change a substantially rectangular irradiation light shape in the heating laser light. The M laser irradiation heads are:
An exit side lens is provided on the irradiation port side that irradiates the heating laser beam,
The single crystal growth apparatus according to any one of claims 1 to 10, wherein a shape of the substantially square irradiation light of the heating laser light is changed by changing a position of the exit side lens. The M laser irradiation heads are:
The single crystal growth apparatus according to claim 11, wherein a width of the irradiation light shape is fixed and a height of the irradiation light shape is changed. The M laser irradiation heads are:
The width of the irradiation light shape of the heating laser light is changed within a range of 7 mm or more and less than 20 mm, and the height of the substantially rectangular irradiation light shape is changed within a range of 3 mm or more and less than 20 mm. The single crystal growing apparatus described. The single crystal growing apparatus according to any one of claims 1 to 13, wherein the M laser irradiation heads output heating laser light having a top-flat irradiation intensity distribution. The raw material rod has a columnar shape,
The number of the M laser irradiation heads is 5,
The single crystal growth apparatus according to any one of claims 1 to 14, wherein an irradiation light intensity from the laser irradiation head has an irradiation light intensity of 2.2 W / mm ² or more. The M laser irradiation heads are:
Having a reflecting mirror disposed on the irradiation port side for irradiating the heating laser beam;
The single crystal growing device according to any one of claims 11 to 15, wherein the reflecting mirror reflects the crystal rod so as to irradiate at least a part of the M heating laser beams. The M laser irradiation heads are:
An exit side cylindrical lens is provided on the irradiation port side that irradiates the heating laser beam,
The single crystal growing apparatus according to any one of claims 1 to 10, wherein the exit side cylindrical lens changes an irradiation light intensity distribution of the M heating laser beams to a bell-shaped intensity distribution. The single crystal growth apparatus according to any one of claims 1 to 17, further comprising an illumination unit that irradiates light for illumination in a region adjacent to the irradiation region of the heating laser light in the raw material rod. N reflecting mirrors and N heating lamps, the light irradiated by the heating lamps is reflected by the reflecting mirrors,
The single crystal growth apparatus according to any one of claims 1 to 18, further comprising a heating auxiliary unit that irradiates the crystal rod. The N reflecting mirrors have a concave shape,
The single crystal growing apparatus according to claim 19, wherein the light irradiated by the heating lamp is reflected linearly on the crystal rod. The single crystal growing apparatus according to claim 20, wherein the N reflecting mirrors have a semi-cylindrical shape. The N reflecting mirrors have a linear focal point on the central axis of the crystal rod, and
The single crystal growing apparatus according to claim 20 or 21, wherein the single crystal growing apparatus has a concave mirror shape in a plane perpendicular to a central axis of the crystal rod. A melting zone monitoring unit for monitoring a melting zone in the raw material rod;
The melting zone monitoring unit
A camera for acquiring a picture of the raw material rod;
An optical filter for attenuating the emitted light from the raw material rod,
The single crystal growing device according to any one of claims 1 to 22, wherein the optical filter includes two polarizers. The two polarizers are
A fixed polarizer arranged with a polarization axis fixed to the camera;
The single crystal growing apparatus according to claim 23, comprising: a rotating polarizer having a mechanism for rotating a direction of a polarization axis with respect to the camera. The single crystal growing apparatus according to any one of claims 1 to 24, further comprising a magnetic field applying unit that applies a magnetic field to the raw material bar. The single crystal growth apparatus according to any one of claims 1 to 24, further comprising a high frequency application unit that applies a high frequency to the raw material rod. A method for producing a single crystal of an oxide compound A ₂ B ₂ C ₁₂ O ₂₂ having a Y-type ferrite structure using the single crystal growth apparatus according to any one of claims 1 to 26,
A includes at least one of Ba, Sr, Sc, and Pb elements,
B includes at least one of Co, Zn, Cu, Cd, Ni, and Mg elements;
C is a production method comprising Fe as a main component and containing at least one of Al, Ga or Mn element. The oxidized compound A ₂ B ₂ C ₁₂ O ₂₂ is
The process according to Formula _{(Ba 1-x Sr x)} 2 Co 2 Fe 12-y Al y O 22, 0 ≦ x ≦ 1,0 consisting ≦ y ≦ 1 claim 27. A method for producing an oxide compound AB ₂ C ₁₆ O ₂₇ having a W-type ferrite structure using the single crystal growth apparatus according to any one of claims 1 to 26,
A includes at least one of Ba, Sr, Sc, and Pb elements,
B includes at least one of Co, Zn, Cu, Cd, Ni, and Mg elements;
C is a production method comprising Fe as a main component and containing at least one of Al, Ga or Mn element. The oxidized compound AB ₂ C ₁₆ O ₂₇ is
The process according to formula _{Ba 1-x Sr x Co 2} Fe 16 -y Al y O 22, 0 ≦ x ≦ 1,0 ≦ y ≦ 1 claim 29 consisting of. A method for growing a single crystal of an oxide compound A ₃ B ₂ C ₂₄ O ₄₁ having a Z-type ferrite structure using the single crystal growth apparatus according to any one of claims 1 to 26,
A includes at least one of Ba, Sr, Sc, and Pb elements,
B includes at least one of Co, Zn, Cu, Cd, Ni, and Mg elements;
C is a production method comprising Fe as a main component and containing at least one of Al, Ga or Mn element. The oxidized compound A ₃ B ₂ C ₂₄ O ₄₁ is
The process according to Formula _{(Ba 1-x Sr x)} 3 Co 2 Fe 24-y Al y O 41, 0 ≦ x ≦ 1,0 claim 31 consisting ≦ y ≦ 1.