JP5780211B2 - Single crystal growth equipment - Google Patents

Description

  The present invention relates to a single crystal growing apparatus used when growing a silicon single crystal by the Czochralski method.

  A CZ method is generally used as a method for producing a silicon single crystal used as a substrate for a semiconductor integrated circuit. In this CZ method, a silicon raw material is melted in a quartz crucible, a seed crystal is deposited in the melt, and then pulled up to grow a single crystal. This manufacturing method can be roughly divided into two from the viewpoint of raw material supply.

  One is a batch method, which does not supply raw materials during single crystal growth. After pulling up the single crystal, it can be finished as it is, but since the crucible is broken and cannot be reused, the single crystal is grown again by recharging the raw material in the crucible from the viewpoint of crucible cost. As the recharging method, there are a method of supplying a raw material from the upper part of the chamber disclosed in Patent Document 1 and a method of supplying by a recharge pipe having a conical valve disclosed in Patent Documents 2 and 3. However, in the batch method, the dopant for controlling the resistivity, which is an important quality for semiconductors, becomes higher in concentration in the second half due to the segregation phenomenon, and there is a problem in terms of uniformity of resistivity. However, compared with problems such as dislocation transformation of single crystal and energy in the continuous method described later, it is highly superior and is the current mainstream.

  The other is a continuous method in which a raw material melt corresponding to a grown single crystal is added continuously or intermittently. This method can eliminate the non-uniformity of resistivity in the axial direction. In Patent Documents 4 and 5, a raw material melting part is provided in the upper part of the main crucible, and a method of supplying a melt from here is adopted. In this configuration, since the melt is supplied from above, a mechanism for supplying a desired amount is indispensable, which increases the cost. Furthermore, there is a problem that the single crystal is dislocated due to melt surface vibrations in the crucible generated by the molten melt.

  In order to solve this problem of dislocation formation, Patent Documents 6 and 7 disclose a method of introducing a raw material to the outside of a double crucible. With such a double crucible, it is possible not to supply a melt but to put an unmelted raw material as it is. However, in reality, even with such a crucible having a complicated shape, it is difficult to completely prevent dislocation of a single crystal, and the crucible cost is high.

  As a method for preventing dislocation, Patent Document 8 discloses a method in which another crucible is provided in addition to the double crucible, and the crucible is connected to the side of the crucible. This method seems to prevent dislocations. However, when the crucibles are connected in this way, there is a problem that the crucible cannot be rotated during crystal growth, and the convection control of the melt and the oxygen concentration control of the single crystal become difficult. The crucible production cost is also easily estimated to be considerable.

  The method disclosed in Patent Document 9 is considered effective as a method for suppressing the dislocation of the single crystal due to the crucible cost or the supplied melt. In Patent Document 9, two or more crucibles are prepared, and the melts can be supplied by connecting the melts contained in the crucibles with a tube that does not touch the crucible. By connecting with such a tube, the height of the melt surface between the crucibles connected by the tube is basically kept at the same height, so a large-scale supply control device is unnecessary, and the supply of the raw material solution There is no worry of dislocation due to.

However, the continuous method described above is not used at all for the production of the current single crystal. This is because, even in the method of Patent Document 9 which seems to be able to solve the above-described problems to some extent, there is a problem that energy is increased by using a plurality of crucibles. No response has been made to such a problem, and it has not been accepted in the recent direction of energy saving and has not been realized.
Further, this Patent Document 9 also describes a method of supplying a melt from a single crucible to a plurality of pullers, and it seems that energy saving can be achieved by using this method. However, in practice, a complicated control technique is required, and in the MCZ method, which is the mainstream for growing single crystals with a diameter of 200 mm or more, there are magnets next to the pullers, so that a plurality of pullers can be adjacent to each other. Difficult, it is not realistic to install it separately because it requires energy to keep the supply pipe warm.

  Furthermore, with the recent improvement in quality of silicon single crystals, defect-free single crystals are often required. In order to grow this defect-free single crystal, it is important to control the distance between the heat shield member attached so as to surround the single crystal and the melt surface. For this distance control, it is necessary to control the height of the melt surface. However, it is difficult to accurately control the height of the melt surface not only in the method of supplying the raw material from above the crucible but also in the method of connecting the crucible with a tube. Therefore, there is a problem that it is difficult to obtain a current mainstream defect-free single crystal in the continuous method.

JP-A-62-260791 JP-A-2-157180 WO2002 / 068732 JP-A-5-279166 JP-A-8-208371 Japanese Patent Laid-Open No. 62-105992 JP 63-79790 A JP 59-8695 A US patent 4410494

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a single crystal growth apparatus that can efficiently grow a silicon single crystal having a uniform axial resistivity distribution. .

In order to achieve the above object, the present invention is a single crystal growing apparatus for growing a silicon single crystal by the Czochralski method,
The single crystal growth apparatus includes a crystal growth chamber for growing the silicon single crystal, a raw material supply chamber for supplying a melt to the crystal growth chamber, and a fusion connecting the crystal growth chamber and the raw material supply chamber. A liquid supply pipe,
The crystal growth chamber has a quartz crucible for storing the melt and a main chamber for storing a heater for heating and keeping the melt, and a pulling chamber for storing the grown silicon single crystal.
The raw material supply chamber includes a raw material supply crucible for melting the raw material, a heater for heating and melting the raw material, and a raw material supply mechanism for supplying the raw material to the raw material supply crucible,
The melt supply pipe is connected to supply the melt from a raw material supply crucible in the raw material supply chamber to a quartz crucible in the crystal growth chamber,
The outer diameter of the quartz crucible in the crystal growth chamber is 2 to 5 times the diameter of the silicon single crystal to be grown, and the aspect ratio (outer diameter / height) of the quartz crucible is 2 to 10. A single crystal growth apparatus characterized by the above is provided.

  As described above, if the raw material supply chamber is provided separately from the crystal growth chamber and these are connected by the melt supply pipe to supply the melt, the resistivity distribution in the axial direction of the silicon single crystal is made uniform. In addition, it is possible to use a quartz crucible having the above-mentioned outer diameter and aspect ratio, thereby reducing the amount of melt to be stored in the quartz crucible. It is also possible to arrange a heat insulating member or the like so that heat loss can be efficiently suppressed. Therefore, the single crystal growth apparatus can improve energy efficiency and productivity in growing a silicon single crystal.

At this time, the outer diameter of the raw material supply crucible is preferably 1/5 to 1 / 1.5 times the outer diameter of the quartz crucible.
If the outer diameter of such a raw material supply crucible is used, the energy saving effect is large, and the melt supply efficiency is improved.

At this time, it is preferable that the crystal growth chamber is provided with a heat insulating member that is above the quartz crucible and covers an upper end portion of the quartz crucible.
According to the present invention, even if the heat insulating member is provided above the quartz crucible as described above, the quartz crucible does not interfere with the vertical movement of the quartz crucible, and the apparatus has a smaller heat loss.

At this time, it is preferable that at least one of the crystal growth chamber and the raw material supply chamber is provided with a crucible lifting / lowering mechanism for controlling the height of the melt surface.
If it has such a crucible raising / lowering mechanism, control of growth conditions etc. is easy and it becomes an apparatus which can grow a silicon single crystal of desired quality.

At this time, at least one of the crystal growth chamber and the raw material supply chamber has a detection mechanism for calculating or detecting the height of the melt surface, and the height of the melt surface calculated or detected by the detection mechanism. Based on the above, it is preferable that the height of the melt surface is controlled to a desired height by the crucible elevating mechanism.
By detecting the height of the melt surface with such a detection mechanism and growing the silicon single crystal while controlling the height of the melt surface, it is possible to reliably grow a silicon single crystal of a desired quality. It becomes a device.

At this time, the melt supply pipe is preferably made of quartz.
If it is made of such a quartz, the melt is not contaminated, and it becomes an apparatus capable of growing a higher quality silicon single crystal with high productivity.

At this time, it is preferable that the melt supply pipe is provided with a heat retaining means for keeping the melt in the melt supply pipe at or above the melting point.
Thereby, it can prevent that the melt in a melt supply pipe solidifies, and it becomes a more efficient apparatus.

  As described above, according to the present invention, an apparatus capable of improving energy efficiency and productivity in growing a silicon single crystal is obtained.

It is the schematic which shows an example of the single crystal growth apparatus of this invention. It is the schematic which shows the single crystal growth apparatus of the conventional batch method.

Hereinafter, the present invention will be described in detail as an example of an embodiment with reference to the drawings, but the present invention is not limited thereto.
In FIG. 1, the schematic of an example of the single crystal growth apparatus of this invention is shown.

  A single crystal growing apparatus 10 in FIG. 1 is a single crystal growing apparatus 10 for growing a silicon single crystal 15 by the Czochralski method (including a magnetic field applied Czochralski method). A crystal growth chamber 30, a raw material supply chamber 17 for supplying a melt 33 to the crystal growth chamber 30, and a melt supply pipe 13 connecting the crystal growth chamber 30 and the raw material supply chamber 17.

  The crystal growth chamber 30 includes a main chamber 11 that stores a quartz crucible 24 that stores the melt 27 and a heater 29 that heats and maintains the melt 27, and a pulling chamber 12 that stores the grown silicon single crystal 15. The raw material supply chamber 17 includes a raw material supply crucible 22 for melting the raw material, a heater 32 for heating and melting the raw material, and a raw material supply mechanism 14 for supplying the raw material to the raw material supply crucible 22. The melt supply pipe 13 is connected so as to supply the melt 33 from the raw material supply crucible 22 in the raw material supply chamber 17 to the quartz crucible 24 in the crystal growth chamber 30.

  The single crystal growth apparatus 10 of the present invention has an outer diameter of the quartz crucible 24 in the crystal growth chamber 30 that is 2 to 5 times the diameter of the silicon single crystal 15 to be grown, and an aspect ratio of the quartz crucible 24 ( The outer diameter / height) is 2-10.

  In such a single crystal growing apparatus 10 for supplying a melt by the raw material supply chamber 17, the resistivity distribution in the axial direction of the silicon single crystal 15 to be grown can be made uniform as compared with a general batch type. In order to grow the crystal 15, the two chambers 17 and 30 are used, and a plurality of heating means are used, so that the energy increases. Therefore, the outer diameter of the quartz crucible 24 provided in the crystal growth chamber 30 is 2 to 5 times the diameter of the silicon single crystal 15 to be grown, and the aspect ratio (outer diameter / height) of the quartz crucible 24 is It shall be 2-10.

In the case of the widely used batch type single crystal growing apparatus 100 as shown in FIG. 2, it is necessary to store a certain amount of melt in the quartz crucible 110 from the beginning because raw materials cannot be added in the middle. The aspect ratio of the quartz crucible 110 is about 1.5 or less.
When using such a quartz crucible 110 to melt a raw material obtained by pulverizing a polycrystal or single crystal lump to a size of several centimeters, the height of the raw material charged into the quartz crucible 110 is Compared to the height when melted into a melt, it is quite high. Therefore, when melting the raw material, it is necessary to lower the quartz crucible 110 so that the raw material does not come into contact with the upper parts such as a heat shield member equipped for the purpose of blocking the radiant heat to the growing silicon single crystal. There is. For this reason, the lower heat insulating member installed below the quartz crucible 110 needs to be separated from the quartz crucible 110 by some distance.

  Further, during the growth of the silicon single crystal, the melt is reduced by the amount of crystallization, but if it is left as it is, the distance between the melt surface and the heat shield member is increased, and the quality of the single crystal changes. In order to prevent this, the quartz crucible 110 is raised by the crucible lifting mechanism so as to keep the height of the melt surface substantially constant. Here, “substantially constant” is described as the demand for defect-free silicon single crystals is increasing along with the recent improvement in quality of silicon single crystals, but the defect quality of defect-free silicon single crystals is controlled. In order to achieve this, a method of controlling the distance between the heat shield member and the melt surface is used, and the height of the melt surface is not completely constant, and may vary from several millimeters to several centimeters. It is.

  In this way, when the quartz crucible 110 is raised to keep the position of the melt surface substantially constant, the upper end of the quartz crucible 110 moves upwards and protrudes into a cold space. Heat loss will increase. Further, since the quartz crucible 110 rises, the upper heat insulating member or the heat shielding member cannot be disposed on the upper end portion of the outer wall of the quartz crucible 110 in order to avoid interference, and a gap is generated. This gap also causes heat loss.

  However, in the present invention, since the melt 33 can be supplied as needed, it is not necessary to store a large amount of the melt 27 in the quartz crucible 24. Further, since the melt 33 is supplied to the quartz crucible 24 as described above, a moving range of, for example, about several centimeters is sufficient, and the space above and below the quartz crucible 24 can be made small. Therefore, it is possible to use the quartz crucible 24 having a relatively low height and a large aspect ratio as compared with a batch type apparatus. By using the quartz crucible 24 having a large aspect ratio, it is possible to reduce the amount of melt to be stored and to reduce heat loss.

For this reason, by increasing the aspect ratio of the quartz crucible 24 to 2 or more, which is sufficiently larger than about 1.5 in the case of a batch method apparatus, an energy saving effect can be exhibited. As the aspect ratio is increased, the depth of the melt 27 in the quartz crucible 24 becomes shallow, and an energy saving effect can be obtained. However, if the aspect ratio is too large, the melt 27 becomes too shallow and dissolves from the quartz crucible 24. Since the oxygen atoms that come out are easily taken into the silicon single crystal 15 and the oxygen concentration in the silicon single crystal 15 becomes difficult to control, the aspect ratio is set to 10 or less.
Further, if the outer diameter of the quartz crucible 24 becomes too large compared to the diameter of the silicon single crystal 15 to be grown, the area to be heated increases. The diameter is 5 times or less. On the other hand, if the diameter of the silicon single crystal 15 is the same as that of the silicon single crystal 15, the space for installing the melt supply pipe 13 can not be taken. 2 times or more is necessary.

  Here, the crystal growth chamber 30 of the single crystal manufacturing apparatus 10 of the present invention includes a graphite crucible 25 that covers the outside of the quartz crucible 24, a crucible support shaft 26 that supports the quartz crucible 24 and the graphite crucible 25, a quartz crucible 24, A seed crystal is formed by a heater 29 disposed around the graphite crucible 25, a side heat insulating member 23 around the outside of the heater 29, a lower heat insulating member 28 disposed below the quartz crucible 24 and the graphite crucible 25, and the wire 20. A gas rectifying cylinder 18 surrounding the silicon single crystal 15 that is grown at the tip end thereof by pulling up 21 is provided. Further, a heat shield member 19 for blocking heat radiation from the heater 29 and the melt 27 can be provided.

  Further, a convection of the melt 27 is suppressed by installing a magnetic field generator (not shown) outside the main chamber 11 in accordance with manufacturing conditions and applying a horizontal or vertical magnetic field to the melt 27. It is also possible to use a so-called MCZ method apparatus for achieving stable growth of the silicon single crystal 15.

The crystal growth chamber 30 is preferably provided with a heat insulating member (upper heat insulating member 16) that is above the quartz crucible 24 and covers the upper end portion of the quartz crucible 24.
For example, by disposing the upper heat insulating member 16 projecting from the outer wall of the quartz crucible 24 to the inside, it is possible to reduce the heat loss from the upper part of the quartz crucible 24 to the upper side of the main chamber 11, and further energy saving. Can be achieved. Alternatively, if the heat shield member 19 is large, the upper end portion of the quartz crucible 24 can be covered with the heat shield member 19.

In the case of a batch method apparatus 100 as shown in FIG. 2, it is necessary to raise the quartz crucible 110 greatly as the melt decreases due to silicon single crystal growth. It is necessary to provide a space for ascending as shown in FIG. The amount of movement of the quartz crucible 110 depends on the initial melt depth and cannot be generally stated, but it usually reaches several tens of centimeters. For this reason, it is necessary to leave a space of at least several tens of centimeters or more, and heat loss to the space and further to the upper side of the main chamber 120 occurs.
However, in the present invention, since the melt 33 can be supplied at any time, there is almost no need for a space for the quartz crucible 24 to rise. The heat shielding member 19) can be provided, and the energy saving effect by this is very large.

The raw material supply chamber 17 includes a heater 32 for heating the raw material and the melt in the raw material supply crucible 22, and a heat insulating member 31 disposed so as to cover them in the raw material supply chamber 17.
In the crystal growth chamber 30, the melt 27 in the quartz crucible 24 is decreased by the silicon single crystal 15 to be grown, but an amount of solid material corresponding thereto is transferred to the raw material supply crucible 22 in the raw material supply chamber 17. It can be supplied through the supply mechanism 14. Thereby, the heights of the melt surfaces in the crucibles 22 and 24 connected by the melt supply pipe 13 are basically the same. Therefore, it is possible to supply the melt 33 from the raw material supply crucible 22 on the raw material supply chamber 17 side to the quartz crucible 24 on the crystal growth chamber 30 side without providing a special mechanism.

The outer diameter of the raw material supply crucible 22 is preferably 1/5 to 1 / 1.5 times the outer diameter of the quartz crucible 24.
The smaller the outer diameter of the raw material supply crucible 22, the smaller the heat loss. If the outer diameter of the quartz crucible 24 is 1 / 1.5 times or less, the energy saving effect can be obtained with certainty. On the other hand, if the size is 1/5 or more, the capacity is sufficient, and the melt 27 in the quartz crucible 24 of the crystal growth chamber 30 that is reduced by the growth of the silicon single crystal 15 can be efficiently replenished. .

In addition, at least one of the crystal growth chamber 30 and the raw material supply chamber 17 is preferably provided with a crucible lifting / lowering mechanism for controlling the height of the melt surface.
By providing the crucible elevating mechanism, it is possible to easily control the position of the melt surface, so that it is possible to efficiently obtain a high-quality silicon single crystal, particularly a defect-free silicon single crystal, which has been demanded in recent years. . Since the melt surfaces of the melts 27 and 33 connected by the melt supply pipe 13 are basically the same, a crucible lifting mechanism is attached to one of the chambers to control the height of the melt surface. If so, it is possible to control the height of the other melt surface to the same height. Of course, it may be controlled by attaching a crucible lifting mechanism to both chambers and synchronizing the heights.

At this time, at least one of the crystal growth chamber 30 and the raw material supply chamber 17 is provided with a detection mechanism for calculating or detecting the height of the melt surface, and the height of the melt surface calculated or detected by the detection mechanism is set. It is preferable that the height of the melt surface is controlled to a desired height by the crucible lifting mechanism.
By controlling the height of the melt surface in this way, it is possible to grow the silicon single crystal 15 having a desired quality with higher accuracy. The height of the melt surface is relatively determined from the difference between the weight of the grown silicon single crystal 15 and the weight of the charged raw material, the inner diameter of the quartz crucible 24 and the raw material supply crucible 22, the amount moved by the crucible lifting mechanism, and the like. It can be easily calculated. However, when the furnace pressure in the crystal growth chamber 30 and the furnace pressure in the material supply chamber 17 are different, it is necessary to consider the pressure difference. On the other hand, the quartz crucible 24 softens at a high temperature and slightly deforms, so that it can be controlled more accurately by using a method that directly detects the height of the melt surface rather than a calculation method. There are various techniques for detecting the height of the melt surface, such as the method of obtaining by laser reflection, the method of obtaining from the position of the reflected image reflected on the melt surface and the distance between the reflected image and the real image, etc. There is no problem.

  The melt supply pipe 13 connects the crystal growth chamber 30 and the raw material supply chamber 17, but is preferably connected so as not to contact the quartz crucible 24 and the raw material supply crucible 22 accommodated in both chambers. Thereby, the high quality silicon single crystal 15 can be grown without interfering with the rotation or vertical movement of the crucible.

The melt supply pipe 13 is preferably made of quartz.
This is because quartz is a substance composed of silicon and oxygen as used in the crucible material, and is a problem-free material for CZ silicon single crystals containing oxygen.

  Since the melt 33 is supplied through the melt supply pipe 13, it is preferable to have a heat retaining means in order to keep the melt 33 above the melting point. As the heat retaining means, for example, the heat insulating member or the like is preferably used for the portion that can be kept warm by the heat insulating member or the like, and the heater or the like is preferably used for the portion that cannot be kept warm by the heat insulating member or the like.

  Using the single crystal growth apparatus 10 of the present invention, the raw material supply in the raw material supply chamber 17 is supplied to the melt 27 accommodated in the quartz crucible 24 in the crystal growth chamber 30 during the pulling of the silicon single crystal 15. The melt 33 accommodated in the crucible 22 can be supplied continuously or intermittently. At this time, the raw material supply mechanism 14 can supply a raw material supply crucible 22 with a raw material obtained by crushing a polycrystal or single crystal lump to a size of several centimeters or a granular polycrystalline raw material.

  By growing a silicon single crystal with such a single crystal growth apparatus of the present invention, the amount of the melt in the quartz crucible can be kept constant to some extent, so that the resistivity in the axial direction of the grown silicon single crystal The distribution can be made uniform, and further, the electric power necessary for growing the silicon single crystal can be suppressed.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.
(Example)
A silicon single crystal was grown using the single crystal growth apparatus 10 of the present invention as shown in FIG. The apparatus 10 is provided with an upper heat insulating member 16 projecting from the outer wall of the quartz crucible 24 to the inside, and further, the distance between the lower heat insulating member 28 and the crucible bottom is reduced to reduce heat loss upward and downward. .

  As the quartz crucible 24, a 24-inch quartz crucible having an outer diameter of about 610 mm and an overall height of about 175 mm was used. Therefore, the aspect ratio is about 3.5. In addition, a crucible raising / lowering mechanism is provided on the crystal growth chamber 30 side, and the quartz crucible 24 can be moved up and down by a maximum of 5 cm, thereby making it possible to control the height of the melt surface. This crucible raising / lowering mechanism is mainly intended to control the height of the melt surface, but when the melt supply from the raw material supply chamber 17 is stopped by the last single crystal pulling and the melt 27 is reduced, It was used to push up the quartz crucible 24 as in the batch method. This makes it possible to reduce wasted melt.

On the other hand, a 12-inch quartz crucible having an outer diameter of about 305 mm was used as the raw material supply crucible 22 for the raw material supply chamber 17. For this reason, the outer diameter of the raw material supply crucible 22 was ½ times the outer diameter of the quartz crucible 24 for crystal growth. Further, a feeder-type raw material supply mechanism 14 capable of supplying raw materials into the raw material supply crucible 22 is provided. Using this, during the growth, granular polycrystalline raw material was intermittently added to compensate for the melt reduced by the single crystal growth. Then, the melt 27 in the quartz crucible 24 on the crystal growth chamber 30 side and the melt 33 in the raw material supply crucible 22 on the raw material supply chamber 17 side are connected by the quartz melt supply pipe 13 so as not to contact both crucibles. Connected. At this time, the quartz melt supply pipe 13 was kept warm by a heater between the crystal growth chamber 30 and the raw material supply chamber 17, and the other areas were kept warm by a heat insulating material.
Single crystal growth was started with the quartz crucible 24 on the crystal growth chamber 30 side filled with 50 kg of raw material melt and the raw material supply crucible 22 on the raw material supply chamber 17 side filled with 10 kg of raw material melt. At this time, an 8-inch single crystal having a diameter of approximately 200 mm and a weight of 120 kg was grown. Accordingly, the outer diameter of the quartz crucible 24 is about three times the diameter of the single crystal.

As described above, the required power during the single crystal growth when growing the single crystal is about 53% on the crystal growth chamber 30 side based on the power in the batch method in the following comparative example, The temperature of the melt supply pipe 13 was about 14%. Even if both are added, the result is about 67%, which is about 2/3 of the case of the batch method apparatus, and power saving is achieved.
In addition, in terms of the quality of the single crystal, the height of the melt surface was calculated from the weight of the grown single crystal and the weight of the raw material added and controlled to a desired value, so that a defect-free single crystal was obtained. I was able to. Furthermore, by growing while mixing the raw material containing boron for resistance adjustment, the axial resistivity could be controlled within ± 8% of the target value.

(Comparative example)
An 8-inch single crystal having a diameter of approximately 200 mm was grown using the batch method single crystal growth apparatus 100 shown in FIG. At this time, as the quartz crucible 110, a single crystal was grown using a 24-inch quartz crucible having an outer diameter of about 610 mm and an overall height of about 420 mm and an aspect ratio of about 1.45. After 150 kg of raw material was put into the quartz crucible 110 and melted, a single crystal having a weight of about 120 kg was grown.
Since it is necessary to provide a movable space at the upper end of the outer wall of the quartz crucible 110, a gap is provided between the heat shield member and the upper heat insulating member. From this point and the point that the lower heat insulating member is separated from the bottom surface of the crucible, the power during straight crystal growth of the single crystal was about 1.5 times higher than that of the example. Further, the resistivity of the grown single crystal in the axial direction has decreased to 73% on the bottom side relative to the resistivity on the top side. When the average value of the top and bottom was expressed as the center value, the center value was ± 15.6%, and the resistivity distribution spread to nearly twice that of the example.

  In the above, a 24-inch (outside diameter 610 mm) quartz crucible was used, but the present invention is not limited to the above-mentioned range. The present invention is most suitable for an apparatus for a large single crystal having a diameter of 450 mm that will be developed in the future. In a large-sized apparatus, it is essential to increase the horizontal direction according to the size of the single crystal to be grown, but the vertical direction also increases accordingly. In that case, the heat loss from the top and bottom becomes enormous, which not only raises the manufacturing cost but may also adversely affect the environment. Therefore, it is preferable to apply the present invention.

In the embodiment, the electric power is about 2/3 as compared with the comparative example, but further power saving is possible by optimizing the crucible size ratio. In particular, in a large apparatus, a sufficient distance between the melt supply pipe and the growing single crystal can be secured, so that the degree of design freedom increases. By optimizing the size of both crucibles, it is possible to achieve greater power savings in large devices.
Further, in the examples, the resistivity distribution in the axial direction was ± 8%, but it is also possible to keep it in a narrower range by improving the method of adding raw materials and dopants. In the N type in which phosphorus having a segregation coefficient smaller than boron is doped, the effect of the present invention can be exhibited more.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

10 ... Single crystal growing device, 11 ... Main chamber, 12 ... Pulling chamber,
13 ... Melt supply pipe, 14 ... Raw material supply mechanism, 15 ... Silicon single crystal,
16 ... Upper heat insulating member, 17 ... Raw material supply chamber, 18 ... Gas rectifier,
19 ... Heat shield member, 20 ... Wire, 21 ... Seed crystal, 22 ... Raw material supply crucible,
23 ... side heat insulating member, 24 ... quartz crucible, 25 ... graphite crucible,
26 ... crucible support shaft, 27, 33 ... melt, 28 ... lower heat insulating member,
29, 32 ... heater, 30 ... crystal growth chamber, 31 ... heat insulation member.

Claims (6)

A single crystal growing apparatus for growing a silicon single crystal by the Czochralski method,
The single crystal growth apparatus includes a crystal growth chamber for growing the silicon single crystal, a raw material supply chamber for supplying a melt to the crystal growth chamber, and a fusion connecting the crystal growth chamber and the raw material supply chamber. A liquid supply pipe,
The crystal growth chamber has a quartz crucible for storing the melt and a main chamber for storing a heater for heating and keeping the melt, and a pulling chamber for storing the grown silicon single crystal.
The raw material supply chamber includes a raw material supply crucible for melting the raw material, a heater for heating and melting the raw material, and a raw material supply mechanism for supplying the raw material to the raw material supply crucible,
The melt supply pipe, from the raw material supply crucible of the material supply chamber, but connected so as to supply the melt to the quartz crucible of the crystal growth chamber,
The outer diameter of the quartz crucible of the crystal growth chamber is 2 to 5 times the diameter of the silicon single crystal to the development, the aspect ratio is the outer diameter / height of the quartz crucible 2 to 10, And the outer diameter of the said raw material supply crucible is 1/5-1 / 1.5 times the outer diameter of the said quartz crucible, The single crystal growing apparatus characterized by the above-mentioned.   The single crystal growth apparatus according to claim 1, wherein the crystal growth chamber includes a heat insulating member that is above the quartz crucible and covers an upper end portion of the quartz crucible.   3. The single unit according to claim 1, wherein at least one of the crystal growth chamber and the raw material supply chamber is provided with a crucible elevating mechanism for controlling the height of the melt surface. Crystal growth device.   At least one of the crystal growth chamber and the raw material supply chamber has a detection mechanism for calculating or detecting the height of the melt surface, and based on the height of the melt surface calculated or detected by the detection mechanism. 4. The apparatus for growing a single crystal according to claim 3, wherein the height of the melt surface is controlled to a desired height by the crucible elevating mechanism.   The single crystal growth apparatus according to any one of claims 1 to 4, wherein the melt supply pipe is made of quartz. 6. The unit according to any one of claims 1 to 5, wherein the melt supply pipe is provided with a heat retaining means for keeping the melt in the melt supply pipe at a temperature higher than the melting point. Crystal growth device.

Images