JP5352245B2 - Compound semiconductor single crystal manufacturing method and crystal growth apparatus - Google Patents

Description

  The present invention relates to a method of manufacturing a compound semiconductor single crystal and a crystal growth apparatus, and more particularly to a technique useful when applied to a method of manufacturing, for example, a ZnTe-based compound semiconductor single crystal by a liquid-sealed Czochralski (LEC) method. .

  Conventionally, a vapor phase growth method, a vertical Bridgman method (VB method), and a vertical temperature gradient annealing method (VGF method) have been used for the growth of a ZnTe-based compound semiconductor single crystal.

  However, in the growth of ZnTe-based compound semiconductor crystals by the vapor phase growth method, it is difficult to add a desired impurity during the growth, and it is difficult to control the resistivity of the ZnTe-based compound semiconductor single crystal. It was. Further, the vapor phase growth method has a drawback that the growth rate of ZnTe crystal is extremely slow, so that it is difficult to obtain a sufficiently large single crystal, and the productivity is low.

  In addition, while manufacturing a ZnTe-based compound semiconductor single crystal by the VB method or the VGF method, a large crystal can be grown, but after cooling, it is cooled to room temperature in a state of being covered with a sealing material. Often, the crystal cracked due to the difference in thermal expansion.

  Therefore, the present inventors use a liquid-sealed Czochralski method (LEC method) in which impurities can be added during crystal growth, like the VB method and the VGF method, to provide a large and high-quality ZnTe system. A technique for growing a compound semiconductor single crystal has been proposed (for example, Patent Document 1).

FIG. 5 is a schematic configuration diagram of a conventional crystal growth apparatus used in the LEC method.
The crystal growth apparatus 100 ′ includes a hermetically sealed high-pressure vessel 1, a bottomed cylindrical pBN outer crucible 8, a pB inner crucible 6 having a communication hole with the outer crucible 8 at the bottom, and an inner crucible 6. The crystal pulling shaft 4 having a seed crystal holding portion at the lower end and the high pressure vessel 1 are arranged concentrically with the lower portion of the raw material melt 12 accommodated in the outer crucible 8 and the inner crucible 6. And a multistage heater 3 that heats and melts the contained raw material 12.

  A rotating shaft 7 is disposed at the center of the high-pressure vessel 1, and an outer crucible holder 5 is placed on the upper end of the rotating shaft 7. The outer crucible 8 is held in a state of being fitted to the outer crucible holder 5, for example. On the other hand, the inner crucible 6 is held by the inner crucible holder 2, and the inner crucible holder 2 is arranged so that the inner crucible 6 is inside the outer crucible 8. For example, the inner crucible holder 2 has a flange 2 a that is engaged with the high-pressure vessel 1 at one end, and an engagement portion 2 b that holds the inner crucible 6 on the inner wall, and the flange 2 a is a top plate of the high-pressure vessel 1. It is fixed by being bottled.

  Further, the crystal pulling shaft 4 is connected to a drive unit (not shown) disposed outside the high-pressure vessel 1 to constitute a rotary pulling mechanism. The rotating shaft 7 is connected to a drive unit (not shown) disposed outside the high-pressure vessel 1 to constitute a crucible rotating mechanism and to constitute an elevating mechanism for the outer crucible holder 5. Note that the rotation of the crystal pulling shaft 4 and the rotating shaft 7 and the movement of the lifting and lowering movement are independently set and controlled.

  6A to 6C are enlarged views of the raw material container (around the crucible) of the crystal growth apparatus shown in FIG. 5, and show the process of crystal growth by the LEC method.

  That is, in the LEC method, first, the raw material 12 is put in the inner crucible 6 and the outer crucible 8, and the raw material 12 is melted by the heater 3 in a state where the surface is covered with the sealant 11, and the melted state is held for a certain time. Thereafter, the seed crystal 9 is brought into contact with the surface of the raw material melt (FIG. 6A).

  Thereafter, the crystal pulling shaft 4 is rotated to form a shoulder portion / body portion of the crystal (FIG. 6B). At this time, the diameter of the body portion of the growth crystal 13 is substantially the same as the inner diameter of the inner crucible 6. Next, after the crystal growth, the crystal pulling shaft 4 is raised to pull the growth crystal 13 and cooled for a predetermined time (FIG. 6C).

According to Patent Document 1, it is possible to grow a large ZnTe-based compound semiconductor single crystal by using the LEC method shown in FIGS. 6A to 6C using the crystal growth apparatus 100 ′ shown in FIG. It has become.
JP 2004-99333 A

  However, when a ZnTe single crystal is grown using the prior application technique, the yield of the single crystal may fluctuate depending on the performance of the crystal growth apparatus (for example, the uniformity in the circumferential direction of the heater). It has been found that it is difficult to grow a high quality ZnTe single crystal. Specifically, when (110) and (100) ZnTe single crystals are grown, the single crystals in the grown crystals may be 90% or more, or may not be single crystals at all.

  The present invention is a technique applicable to crystal growth utilizing the LEC method, and an object thereof is to provide a compound semiconductor single crystal manufacturing method and a crystal growth apparatus capable of manufacturing a large ZnTe-based compound semiconductor single crystal with high yield. To do.

In order to achieve the above object, the present invention provides a second crucible having a bottomed cylindrical shape, and a second crucible disposed inside the first crucible and provided with a communication hole for the first crucible at the bottom. A raw material melt containing part composed of a crucible contains a semiconductor raw material and a sealant, and the raw material containing part is heated to melt the raw material, and in this state, the seed crystal contacts the surface of the raw material melt A compound semiconductor single crystal manufacturing method by a liquid-sealed Czochralski method in which the seed crystal is grown while pulling up the seed crystal, wherein both the first crucible and the second crucible are 6 rpm or more and 10 rpm or less. characterized Rutotomoni rotate in the same circumferential direction at the same rotational speed, in accordance with the decrease of the raw material melt by crystal growth, the crystal growth is performed while increasing the first crucible to the second crucible And

Production method of the above-mentioned compound semiconductor single crystal, for example, a dense closed possible high pressure vessel, a first crucible which is rotatably and vertically movably disposed in a central portion of the high pressure vessel, the inside of the first crucible And a second crucible having a communication hole with the first crucible at the bottom and a material crucible accommodated in the second crucible are provided so as to be movable up and down, and a seed crystal is held at the lower end. A crystal pulling shaft having a portion, a heater arranged concentrically with the high-pressure vessel, for heating and melting the raw materials contained in the first crucible and the second crucible, the first crucible or the second crucible One of the first crucible and the second crucible is a crystal growth apparatus comprising: a rotation driving unit that rotationally drives any one of the crucibles; and a control unit that controls raising and lowering of the first crucible. In the rotation drive means Is rotated I and the other is configured to rotate in conjunction with rotation of the one of the crucible, said control means, said first crucible, relative to the second crucible, by crystal growth is realized by utilizing the crystal growth apparatus is characterized in that the so that controls so as to increase in accordance with the decrease of the raw material melt.

  Thereby, even if it is a case where the temperature of the circumferential direction of a heater is not sufficiently uniform, the temperature difference of the raw material melt melted by heating can be reduced.

  The transmission mechanism for interlocking the first crucible and the second crucible is not particularly limited. For example, one of the first crucible and the second crucible is a nail (convex portion), and the other is a nail (convex portion). ) Or a claw support (concave portion), or a gear on one side and a pawl on the other, can be easily interlocked.

Below, the background that led to the completion of the present invention will be described.
First, when the present inventors grew a ZnTe single crystal using the technique described in Patent Document 1, it was difficult to stably grow a good quality ZnTe single crystal because the single crystal yield fluctuated. It turned out to be.

  Then, in order to find out the cause of the fluctuation of the single crystal yield of the ZnTe single crystal, the temperature of the raw material melt in the inner crucible was measured, and a temperature difference of about 4 ° C. occurred in the circumferential direction, and was not uniform. There was found.

  Factors causing the temperature difference of the raw material melt include (1) temperature variation in the circumferential direction of the heater, (2) non-uniform gas flow in the high-pressure vessel, (3) inner crucible, outer crucible, heater In particular, (1) The temperature variation in the circumferential direction of the heater is ± 15 ° C at the foot (hem) part of the heater normally used, and ± 10 ° C at the center. Therefore, it was considered that the temperature difference of the raw material melt had the largest influence.

  Therefore, when melting the raw material melt, we studied a method to reduce the effect of temperature variations in the circumferential direction of the heater and prevent the temperature difference of the raw material melt from occurring, and by rotating the crucible, We thought that the temperature in the circumferential direction of the liquid could be made uniform. Further, since the outer crucible (outer crucible holder) is originally placed on the rotating shaft, a method of effectively using the rotation of the outer crucible was considered.

  And when the temperature difference of the raw material melt when the outer crucible was rotated was examined, the temperature difference of the raw material melt was reduced as compared with the case where the outer crucible was not rotated. However, a temperature difference of about 3 ° C. still remains, which is considered insufficient to improve the single crystal yield of the ZnTe single crystal.

  Furthermore, in order to avoid complication of the crystal growth apparatus, when the inner crucible is rotated using the rotation of the outer crucible (that is, the rotation speed of the outer crucible and the inner crucible becomes the same), the raw material melt The temperature difference of 1 ° C. could be reduced to 1 ° C. or less, and the single crystal yield could be remarkably improved.

  Specifically, the temperature difference could be reduced to 1 ° C. or less by setting the rotation speed to 5 rpm or more. On the other hand, it was found that when the rotational speed exceeds 20 rpm, the raw material melt flows, which is not preferable.

  Moreover, when the rotational speed is in the range of 6-10 rpm, the temperature difference of the raw material melt can be reduced to 1 ° C. or less, and the single crystal in the grown crystal is always 70% or more, and the single crystal yield is stabilized. I was able to.

  Note that the same effect may be obtained when only the inner crucible is rotated. However, in order to rotate only the inner crucible, it is necessary to newly provide a driving means for rotationally driving the inner crucible, which is undesirable from the viewpoint of complicating the crystal growth apparatus.

  The present invention has been completed on the basis of the above knowledge, and in a method for producing a compound semiconductor single crystal by a liquid-sealed Czochralski method, while rotating an outer crucible and an inner crucible in a circumferential direction at a predetermined rotational speed. It is characterized by crystal growth.

  According to the present invention, the first crucible having a bottomed cylindrical shape and a second crucible disposed inside the first crucible and provided with a communication hole with the first crucible at the bottom are configured. In the raw material melt container, the semiconductor raw material and the sealant are accommodated, the raw material container is heated to melt the raw material, and in this state, the seed crystal is brought into contact with the surface of the raw material melt, In the method of manufacturing a compound semiconductor single crystal by the liquid-sealed Czochralski method in which crystal growth is performed while pulling up the crystal, crystal growth is performed while rotating the first crucible and the second crucible in a circumferential direction at a predetermined rotational speed. Since it performed, it can reduce efficiently that the temperature difference of the circumferential direction arises in the raw material melt accommodated in the inner crucible. As a result, the single crystallization rate of the ZnTe-based compound semiconductor single crystal can be improved, and the single crystal yield can be stabilized.

In addition, even if the heater itself has temperature variations in the circumferential direction, the temperature difference of the raw material melt can be reduced, so there is no need to replace it with a heater with good uniformity, minimizing costs associated with equipment improvements. Can do.
Furthermore, since the first crucible rises with the decrease in the raw material melt accompanying the crystal growth, the second crucible is maintained immersed in the raw material melt at a predetermined depth. It is possible to maintain a state in which the temperature difference is small.

It is a schematic block diagram of the crystal growth apparatus used for this embodiment. FIG. 6 is a top view showing an example of an engagement state between the inner crucible holder 2 and the outer crucible holder 5. It is the result of having measured the temperature of the circumferential direction about the raw material melt in the inner crucible 6 when using the crystal growth apparatus (FIG. 1) which concerns on this embodiment. It is the result of having measured the temperature of the circumferential direction about the raw material melt in the inner crucible 6 when using the conventional crystal growth apparatus (FIG. 5). It is a schematic block diagram of the conventional crystal growth apparatus. It is explanatory drawing which shows the crystal growth process by LEC method. It is explanatory drawing which shows the crystal growth process by LEC method. It is explanatory drawing which shows the crystal growth process by LEC method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High pressure vessel 2 Inner crucible holder 2a flange 2b Crucible holding part 21 Claw (engagement piece)
3 Multi-stage heater 4 Crystal pulling shaft 5 Outer crucible holder 51 Claw (engagement piece)
6 Inner crucible (second crucible)
7 Rotating shaft 8 Outer crucible (first crucible)
9 Seed crystal 10 Bearing 11 Sealant 12 Raw material melt 100 Crystal growth device

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a crystal growth apparatus according to this embodiment. The crystal growth apparatus 100 shown in the present embodiment is different from the conventional crystal growth apparatus 100 ′ shown in FIG. 5 in the installation method of the inner crucible holder 2, and the inner crucible holder 2 rotates in conjunction with the rotation of the outer crucible holder 5. It is supposed to be. The details of the crucible rotation mechanism will be described later.

  The crystal growth apparatus 100 includes a hermetically sealed high-pressure vessel 1, a bottomed cylindrical outer crucible 8 made of pBN, an inner crucible 6 made of pB open at the bottom and communicated with the outer crucible 8, and an inner crucible 6. The crystal pulling shaft 4 having a seed crystal holding portion at the lower end and the high pressure vessel 1 are arranged concentrically with the lower portion of the raw material melt 12 accommodated in the outer crucible 8 and the inner crucible 6. And a multistage heater 3 that heats and melts the contained raw material 12.

  A rotating shaft 7 is disposed at the center of the high-pressure vessel 1, and an outer crucible holder 5 is placed on the upper end of the rotating shaft 7. The outer crucible 8 is held in a state of being fitted to the outer crucible holder 5, for example. On the other hand, the inner crucible 6 is held by the inner crucible holder 2, and the inner crucible holder 2 is arranged so that the inner crucible 6 is inside the outer crucible 8.

  Here, the inner crucible holder 2 has a flange 2a engaged with the high-pressure vessel 1 at one end and an engaging portion 2b for holding the inner crucible 6 on the inner wall. Further, a ball bearing 10 is laid in an annular shape on the top plate of the high-pressure vessel 1. By engaging a predetermined portion of the flange 2 a of the inner crucible holder 2 with the bearing 10, the inner crucible holder 2 is rotatably attached to the high-pressure vessel 1.

  Further, the inner crucible holder 2 is engaged with the outer crucible holder 5 so as to rotate in conjunction with the rotation operation of the outer crucible holder 5. That is, a transmission mechanism for interlocking the inner crucible holder 2 and the outer crucible holder 5 is provided.

FIG. 2 is a top view showing an example of an engaged state of the inner crucible holder 2 and the outer crucible holder 5.
As shown in FIG. 2, claws 51 protrude outwardly at two locations on the outer wall surface of the outer crucible holder 5, and claws 21 protrude toward the inner side at two locations on the inner wall surface of the inner crucible holder 2. It is installed. In FIG. 2, when the outer crucible holder 5 rotates counterclockwise, the claw 51 and the claw 21 are engaged, and the inner crucible holder 2 also rotates counterclockwise.

  The outer crucible 8 is merely placed on the outer crucible holder 5 without using any special engagement means, but rotates with the rotation of the outer crucible holder 5. Further, since the inner crucible 6 is fixed by the engaging portion 2 b provided in the inner crucible holder 2, the inner crucible 6 rotates with the rotation of the inner crucible holder 2.

  That is, the fact that the inner crucible holder 2 rotates in conjunction with the rotating operation of the outer crucible holder 5 can be rephrased as the inner crucible 6 rotates in conjunction with the rotating operation of the outer crucible 8. As described above, in the crystal growth apparatus 100 of the present embodiment, the outer crucible 8 and the inner crucible 6 can be rotated by using the rotary shaft 7 provided conventionally, so that the inner crucible 6 is rotated. A mechanism for rotating the outer crucible 8 and the inner crucible 6 can be realized at a relatively low cost without complicating the apparatus configuration, such as providing a new source.

  Further, the crystal pulling shaft 4 is connected to a drive unit (not shown) disposed outside the high-pressure vessel 1 to constitute a rotary pulling mechanism. The rotating shaft 7 is connected to a drive unit (not shown) disposed outside the high-pressure vessel 1 to constitute a crucible rotating mechanism and to constitute an elevating mechanism for the outer crucible holder 5. Note that the rotation of the crystal pulling shaft 4 and the rotating shaft 7 and the movement of the lifting and lowering movement are independently set and controlled.

  FIG. 3 shows the result of measuring the temperature in the circumferential direction of the raw material melt in the inner crucible 6 when the crystal growth apparatus (FIG. 1) according to the present embodiment is used. For example, the temperature difference in the circumferential direction of the raw material melt when both the outer crucible 8 and the inner crucible 6 are rotated at a rotational speed of 5 to 10 rpm is shown. Specifically, the temperature at a position 5 mm away from the inner wall of the inner crucible 6 is measured in increments of 45 ° C. in the circumferential direction.

  As shown in FIG. 3, by rotating the outer crucible 8 and the inner crucible 6 at a rotational speed of 5 to 20 rpm, the temperature difference in the circumferential direction of the raw material melt can be controlled to 1 ° C. or less and can be made uniform. It was. For example, when the temperature difference in the circumferential direction of the heater 3 is about 30 ° C., it is possible to effectively cope with the rotation speed within the above range.

  FIG. 4 shows the results of measuring the temperature in the circumferential direction of the raw material melt in the inner crucible 6 when the conventional crystal growth apparatus (FIG. 5) is used. Note that the legend of ■ indicates the case where the outer crucible 8 is not rotated, and the legend of ▲ indicates the temperature difference in the circumferential direction of the raw material melt when only the outer crucible 8 is rotated at a rotational speed of 5 rpm.

  As shown in FIG. 4, it can be seen that when the outer crucible 8 is rotated, the temperature difference of the raw material melt is reduced as compared with the case where the outer crucible 8 is not rotated. However, a temperature difference of about 3 ° C. remains, and the temperature difference of the raw material melt is larger than when the inner crucible 6 is rotated in conjunction with the outer crucible 8 and the single crystal yield of the ZnTe single crystal is improved. It is not enough to make it happen.

  As described above, by using the crystal growth apparatus 100, the temperature difference of the raw material melt in the inner crucible 6 can be effectively reduced, and a large ZnTe-based compound semiconductor single crystal can be obtained with a high yield by the LEC method. Can be grown.

  Next, a method for manufacturing a ZnTe single crystal as an example of a compound semiconductor using the crystal growth apparatus 100 will be specifically described.

  In this embodiment, a pBN crucible having an inner diameter of 100 mmφ × height of 100 mm × thickness of 1 mm is used as the outer crucible 8, and an inner crucible 6 of inner diameter of 54 mmφ (bottom) to 56 mmφ (top) × height of 100 mm × thickness of 1 mm. A pBN crucible having a tapered structure was used. At this time, the inclination angle θ of the side surface of the inner crucible 6 is about 0.57 ° with respect to the vertical direction.

First, Zn of a purity of 6N and Te of 6N as raw materials are put in a total of 1.5 kg in the outer crucible 8 and the inner crucible so that Zn and Te are in an equimolar ratio, and 400 g of a sealing agent (B ₂ It was covered with O ₃ ) 11 so that the thickness of the sealant layer was 35 mm. The inner crucible 6 was fixed with a holder so that the raw material was melted by the heater 3 and then immersed at a depth of 20 mm from the surface of the raw material melt.

  Although the raw material melt gradually decreases as the crystal grows, the immersion state of the inner crucible 6 was controlled by raising the outer crucible holder susceptor 5 (outer crucible 8) by driving the rotary shaft 7 up and down. For example, the inner crucible 6 is held in a state of being immersed in a range of 10 mm to 40 mm from the liquid surface of the raw material melt.

  Next, the inside of the high-pressure vessel 1 was filled with an inert gas (for example, Ar) and adjusted so as to have a predetermined pressure. And while suppressing the surface of the raw material 12 with the sealing agent 11, it heated at predetermined temperature using the heater 3, and melt | dissolved Zn and Te directly and synthesize | combined them.

  At this time, the outer crucible was rotated by rotating the rotating shaft 7. Further, the inner crucible 6 was rotated at the same rotational speed in conjunction with the rotation operation of the outer crucible 8. Thus, by rotating the inner crucible 6 and the outer crucible 8 at the same speed, the temperature difference in the circumferential direction of the raw material melt 12 could be 1 ° C. or less (for example, FIG. 3).

  Thereafter, after the raw material was melted and held for a certain time, the seed crystal 9 was brought into contact with the surface of the raw material melt 12. Here, a seed crystal having a crystal orientation of (100) was used as the seed crystal. Further, in order to prevent the seed crystal 9 from being decomposed, the seed crystal was covered with a molybdenum cover (not shown).

  Then, the crystal pulling shaft 4 was rotated at a rotational speed of 1 to 2 rpm, and a shoulder portion of the crystal was formed while pulling up at a speed of 2.5 mm / h. Subsequently, after the shoulder portion was formed, the body portion was formed while being pulled up at a speed of 2.5 mm / h. At this time, the rotating shaft 7 was rotated at 0 to 10 rpm.

  As described above, crystal growth was performed by the liquid-sealed Czochralski method, and after the crystal growth, the grown crystal was separated from the encapsulant 11 to obtain a ZnTe compound semiconductor crystal having no cracks. The obtained ZnTe compound semiconductor crystal was a very good single crystal free of polycrystals or twins.

  Further, the size of the grown crystal was 54 mmφ × 60 mm in length, and it was possible to realize the enlargement of the ZnTe-based compound semiconductor single crystal, which was conventionally considered difficult. Furthermore, when ZnTe single crystals were repeatedly grown using the same crystal growth apparatus, 90% or more of the grown crystals became single crystals, and it was confirmed that the single crystal yield was greatly improved.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments.
For example, in the above embodiment, the outer crucible 8 and the inner crucible 6 are provided with claws (projections), but the transmission mechanism for interlocking the outer crucible 8 and the inner crucible 6 is not limited to this. For example, a claw (convex portion) is provided on one of the outer crucible 8 and the inner crucible 6, a claw receptacle (concave portion) is provided on the other side, a gear is provided on one side, and a pawl is provided on the other side. .

  In the above embodiment, the bottom of the inner crucible 6 is opened to communicate with the outer crucible 8, but one communication hole of a predetermined size may be formed on the bottom surface of the inner crucible 6. However, the number of communication holes is not limited to one, and a plurality of communication holes may be provided.

  In addition, the same effect may be obtained even when only the inner crucible 6 is rotated or when the rotational speeds of the outer crucible 8 and the inner crucible 6 are different. However, in order to rotate only the inner crucible 6, it is necessary to newly provide a driving means for rotationally driving the inner crucible, which may lead to the complexity and cost increase of the crystal growth apparatus.

  In addition, not only ZnTe single crystals but also ternary or higher ZnTe-based compound semiconductor single crystals containing ZnTe and other compound semiconductor single crystals can be applied to produce large and high quality compound semiconductor single crystals. Can be obtained.

Claims (2)

A raw material melt container comprising a first cylindrical crucible with a bottom, and a second crucible disposed inside the first crucible and provided with a communication hole with the first crucible at the bottom. Next, the semiconductor raw material and the sealant are accommodated, the raw material accommodating portion is heated to melt the raw material, and in this state, the seed crystal is brought into contact with the surface of the raw material melt, and crystal growth is performed while pulling up the seed crystal. A method for producing a compound semiconductor single crystal by a liquid-sealed Czochralski method,
Said first crucible and said second crucible is rotated in the same circumferential direction together with 10rpm following the same rotational speed or 6rpm Rutotomoni,
A method for producing a compound semiconductor single crystal, wherein crystal growth is performed while raising the first crucible relative to the second crucible in accordance with a decrease in raw material melt accompanying crystal growth . A sealable high-pressure vessel;
A first crucible disposed at the center of the high-pressure vessel so as to be rotatable and movable up and down;
A second crucible disposed inside the first crucible and having a communication hole with the first crucible at the bottom;
A crystal pulling shaft provided so as to be movable up and down above the raw material melt contained in the second crucible and having a seed crystal holding portion at the lower end;
A heater arranged concentrically with the high-pressure vessel, for heating and melting the raw materials contained in the first crucible and the second crucible;
Rotation driving means for rotating and driving either the first crucible or the second crucible;
Control means for controlling raising and lowering of the first crucible;
A crystal growth apparatus comprising:
One of the first crucible or the second crucible is rotationally driven by the rotational drive means, and the other is configured to rotate in conjunction with the rotational operation of the one crucible,
The crystal growth apparatus characterized in that the control means controls the first crucible to rise with the decrease in the raw material melt accompanying the crystal growth with respect to the second crucible .

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