JPH09263483A - Apparatus for producing single crystal and puroduction thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an apparatus for producing a single crystal capable of suppressing the intrusion of impurities from outside into the melt in a quarts crucible and the splashing of the melt to outside and lessening heat radiation loss by making the opening diameter of an upper aperture smaller than the max. dore of a crucible. SOLUTION: The quartz crucible 10 in which the silicon melt 2 obtd. by melting polycrystalline silicon raw materials is housed is rotationally driven around the center of a chamber 5 by a revolving shaft 3. After a silicon seed 6 hung down from above is immersed into the melt 2, the silicon seed is pulled up and the silicon single crystal 8 is pulled up under rotation, by which the silicon single crystal is produced. The crucible of which the opening diameter of the upper aperture is specified to 0.75 to 0.95 times the max. bore of the crucible is used as the quartz crucible 10 of the apparatus. The upper aperture of the crucible may be formed integrally as shown in Fig. or the upper aperture may be formed mounting an upper cover to the upper edge of the cylindrical crucible and drawing the aperture.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to semiconductors, derivatives,
The present invention relates to an apparatus for manufacturing various crystal materials such as magnetic materials and a manufacturing method using the apparatus. In particular, it relates to an apparatus for manufacturing a semiconductor single crystal by the Czochralski method and a manufacturing method using the apparatus.

[0002]

2. Description of the Related Art The so-called Czochralski method is widely used as a method for producing a semiconductor single crystal. In this method, a seed crystal is dipped in a melt of silicon or the like contained in a quartz crucible, and the seed crystal is pulled up to grow a semiconductor single crystal ingot.

FIG. 6 shows an example of an apparatus for producing a silicon single crystal by the Czochralski method. This apparatus includes a quartz crucible 1 containing a silicon melt 2 obtained by melting a polycrystalline silicon raw material, a heater 4 arranged around the quartz crucible 1, a heat insulating material arranged around the heater 4 ( (Not shown) is housed in the chamber 5. The quartz crucible 1 is driven to rotate about the center of the chamber 5 by the rotating shaft 3.

When a silicon single crystal is grown using the above-mentioned single crystal manufacturing apparatus, a polycrystalline silicon raw material is put into the quartz crucible 1 and then the polycrystalline silicon is heated by the heater 4 to a temperature higher than the melting point of the silicon melt. Set to 2. In this state, the silicon seed 6 hung from above is immersed in the silicon melt 2 in the quartz crucible 1 and the silicon seed 6 is pulled up while being rotated by the pulling drive mechanism 7, whereby the silicon single crystal 8 grows in a rod shape. Then, a desired silicon single crystal is obtained.

[0005]

When a silicon single crystal is produced by this method, the silicon melt 2 and the quartz crucible 1 containing the silicon melt 2 react with each other to react with volatile silicon monoxide (hereinafter referred to as "SiO"). May be generated and may be deposited on the heat insulating material or on the inner wall of the chamber 5. If such condensed SiO falls onto the silicon melt 2 when pulling up the silicon single crystal 8, crystal defects may occur in the grown silicon single crystal 8 or the single crystallization may be incomplete, resulting in a large number of parts. It may cause a defect such as crystallization.

Generally, in the quartz crucible used in the Czochralski method, the side wall portion has a cylindrical shape as shown in FIG. 5, and it is easy for impurities such as SiO described above to enter from the outside. In addition to problems, there is a risk that the silicon melt will scatter outside when vibration is applied due to an earthquake, etc., and damage the heater, heat insulating material, etc., and in the worst case, the chamber may be damaged and vapor explosion may occur. is there. Further, the silicon melt in the quartz crucible is melted and heated and held by the heater. However, since the diameter of the upper opening of the quartz crucible is large, there is a problem that the heat radiation loss is large.

With the recent increase in the diameter of semiconductor single crystals, the amount of melt during the manufacturing process has increased. Therefore, the operation damage per operation due to the above problems is large, and especially equipment damage such as steam explosion may be a fatal problem.

The present invention has been made in view of the above problems, and prevents impurities from being mixed into the melt in the quartz crucible from the outside and the melt from scattering to the outside, and also reduces heat radiation loss. It is an object of the present invention to provide a single crystal production apparatus capable of performing the same and a production method using the same.

[0009]

According to the invention of claim 1 of the present application, the opening diameter of the upper opening is 0.75 of the maximum inner diameter of the crucible.
Provided is a single crystal manufacturing apparatus having a crucible that is more than twice and less than 0.95 times.

The invention according to claim 2 of the present application provides the apparatus according to claim 1, wherein the upper opening is integrally formed with the crucible.

The invention according to claim 3 of the present application provides the single crystal manufacturing apparatus according to claim 1 or 2, wherein the upper opening is an upper cover attached to the upper edge of the crucible. .

According to a fourth aspect of the present invention, there is provided a method for producing a single crystal using the apparatus for producing a single crystal according to any one of the first to third aspects.

Next, the present invention will be described in more detail.

The single crystal production apparatus according to claim 1 of the present application is
The opening diameter of the upper opening of the crucible is 0.75 times or more and 0.95 times or less of the maximum inner diameter of the crucible.
As described above, since the opening diameter of the upper opening of the crucible is relatively small, it is difficult for impurities to be mixed into the melt in the crucible, so that problems such as occurrence of crystal defects due to mixing of impurities or polycrystallization are prevented. be able to. Further, since the melt does not easily scatter to the outside, it is possible to prevent an accident due to the splash of the melt and enhance safety. further,
Since the heat radiation loss is also small, the heater power can be reduced. When the opening diameter of the upper opening of the crucible is larger than 0.95 times the maximum inner diameter of the crucible, these effects are hardly obtained.

On the other hand, since the opening diameter of the upper opening of the crucible is 0.75 times or more of the maximum inner diameter of the crucible, the inert gas such as argon flowing from the upper part of the chamber of the single crystal manufacturing apparatus does not stagnant and the single crystal does not stagnant. Can be raised. If this value is less than 0.75 times, the inert gas tends to stagnant in the crucible, which is not preferable.

The single crystal production apparatus according to claim 2 of the present application is
In the structure according to the first aspect, since the upper opening of the crucible is formed integrally with the crucible body, there are advantages such as easy handling.

The single crystal production apparatus according to claim 3 of the present application is
In the structure according to claim 1 or 2, since the upper opening of the crucible is provided as an upper cover that can be separated from the crucible body, there are advantages such as easy manufacture of the crucible.

According to the invention of claim 4 of the present application, a single crystal is produced by using the apparatus for producing a single crystal according to any one of claims 1 to 3, so that generation of crystal defects and polycrystallization are not caused. A single crystal can be manufactured efficiently and safely.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view showing an embodiment of a single crystal manufacturing apparatus of the present invention. The apparatus shown in this figure has the same basic configuration as the apparatus shown in FIG. 5, except for the crucible. That is, a quartz crucible 10 containing a silicon melt 2 obtained by melting a polycrystalline silicon raw material, the quartz crucible 1
The heater 4 is arranged around 0, and a heat insulating material (not shown) arranged around the heater 4 is housed in the chamber 5. The quartz crucible 10 is driven to rotate about the center of the chamber 5 by the rotating shaft 3. The silicon seed 6 suspended from above is immersed in the silicon melt 2 and then raised by the pulling drive mechanism 7, and the silicon single crystal 8 is pulled while rotating along its central axis. Although not shown, a cylindrical heat insulating material may be arranged on the outside of the heater 4, if necessary, as in the apparatus of FIG.

The difference between the apparatus of this embodiment and the conventional apparatus shown in FIG. 5 is that the opening diameter of the upper opening of the crucible 10 is smaller than the maximum inner diameter. That is,
As shown in FIG. 2, the upper opening 10a of the crucible 10 has a spherically narrowed shape. The opening diameter X of the upper opening 10a of the crucible 10 is 0.95 times or less than the maximum inner diameter Y, and the upper opening 10a is not larger than the crucible 10.
It is formed integrally with the main body.

By forming the crucible 10 into the above-described shape, the probability that SiO deposited on the inner wall of the chamber 5 or the like will drop onto the silicon melt 2 decreases, and crystal defects occur in the grown silicon single crystal 8. Alternatively, it is possible to reduce the occurrence of defects such as incomplete single crystallization and generation of polycrystals. In addition, when a large vibration is applied to the crucible 10 and the silicon melt 2 due to an earthquake or the like, in a crucible of a commonly used shape, the silicon melt is splashed upward along the side wall of the crucible and may be scattered to the outside in some cases. However, in the present embodiment, since the upper opening 10a projects inward and the opening diameter is small, the melt scattering direction is bent in the crucible inner peripheral direction, and scattering to the outside is suppressed. Further, a part of the heat radiation from the melt surface to the heat insulating material and the inner wall of the chamber is part of the upper opening 10.
It is blocked by a, heat dissipation loss is reduced, and the heat retention of the melt is improved.

Needless to say, the present invention is not limited to the above-described embodiment, and various modifications and substitutions are possible. For example, in the above embodiment, the quartz crucible has an integrated structure in which the upper opening is narrowed, but the upper opening and the crucible body may not be integrally formed.

Crucible 20 shown in FIGS. 3 and 4, respectively.
The upper covers 21 and 31 formed separately from the crucible body are attached to the upper edge portions of the crucible body, respectively. Even in these cases, the opening diameter X of the openings 21a and 31a of the upper covers 21 and 31 is 0.95 times or less than the maximum inner diameter Y. In this case, the material of the upper cover does not necessarily have to be the same quartz glass as that of the crucible body, and other materials satisfying the conditions can be used. The crucible body may be the same as the conventional one.

The upper opening of the crucible or the upper cover may have various shapes. For example, not only spherical shapes, but also annular plate shapes, cone shapes, etc.
Various shapes are possible.

Furthermore, the present invention is not limited to the case of manufacturing a silicon single crystal by the CZ method, but can be applied to the pulling of a semiconductor other than silicon, a compound semiconductor, or an oxide single crystal.

[0027]

EXAMPLE Using the apparatus shown in FIG. 1, a quartz crucible of 18 ″ φ having crucibles whose upper opening diameters are 0.7, 0.8, 0.9 and 1.0 of the maximum inner diameter of the crucible, respectively. Prepare, put 60 kg of polycrystalline silicon in a crucible and melt it. Make the pulling speed and other conditions the same and set to 6 ".
The φ silicon single crystal was pulled up using each crucible. FIG. 5 shows the heater power when the crucible having each opening diameter is used. As a result, the heater power decreases as the opening diameter of the upper part of the crucible becomes smaller, and in particular, when the opening diameter is 0.7, it is reduced by about 14% compared to when the opening diameter is 1.0, and when the opening diameter is 0.95, it is reduced. 2.5% reduction.

[0028]

As is apparent from the above description, according to the present invention, it is possible to suppress the defect growth of a single crystal and the growth of polycrystal, so that the economical possibility of the crystal growth process can be improved. it can. Further, the safety is improved by suppressing the melt scattering.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a single crystal manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a crucible according to an embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing a crucible according to another embodiment of the present invention.

FIG. 4 is a vertical sectional view showing a crucible according to another embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between an opening diameter of a crucible and heater power.

FIG. 6 is a vertical sectional view showing an example of a conventional single crystal manufacturing apparatus.

[Explanation of symbols]

 2 Silicon melt 3 Crucible rotation shaft 4 Heater 5 Chamber 6 Single crystal seed 7 Pulling drive mechanism 8 Silicon single crystal 10,20 Crucible 10a, 21a, 31a Upper opening 21, 31 Upper cover

Claims (4)

[Claims] 1. An apparatus for producing a single crystal comprising a crucible having an opening diameter of an upper opening which is 0.75 times or more and 0.95 times or less of a maximum inner diameter of the crucible. 2. The single crystal manufacturing apparatus according to claim 1, wherein the upper opening is formed integrally with the crucible. 3. The single crystal manufacturing apparatus according to claim 1, wherein the upper opening is an upper cover attached to an upper edge of the crucible. 4. A method for producing a single crystal using the apparatus for producing a single crystal according to claim 1.