JP2000154088A - Method and device for producing single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method which enables improvement in yield of single crystal growth by preventing any damage to a seed crystal from being caused through reaction of a raw material before the crystal synthesis with the seed crystal and also to provide the device for the method. SOLUTION: This device is provided with a first vessel 8 for receiving a seed crystal 9 and growing a single crystal, a heating means 12 placed so as to encircle the first vessel 8; and a second vessel 3 that is placed above the first vessel 8 and has an opening 6 at the bottom and is used for receiving a raw material 4 for single crystal growth wherein the second vessel 3 is attachable and detachable and includes a sealing means 7 for sealing the opening 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a single crystal, and more particularly, to GaAs, InP.
III-V compound semiconductor materials such as CdTe, Zn
II-VI group compound semiconductor materials such as Se, and Si
The present invention relates to a method and an apparatus for producing a single crystal such as a material generated by combining a plurality of elements such as Ge.

[0002]

2. Description of the Related Art As an example of a conventional method and apparatus for producing a single crystal, for example, Japanese Patent Application Laid-Open No. Hei 10-13098 discloses a method and apparatus for growing a binary compound semiconductor single crystal.

In this method and apparatus, an element B corresponding to a high vapor pressure component element is sequentially placed in a crucible from below,
The raw material A corresponding to the other element is mixed with the raw material A without mixing.
The compound semiconductor single crystal is grown after the raw material B of the high dissociation pressure component element is filled from the lower part of the growth vessel with the vapor of the raw material B, and the raw material is directly synthesized in the crucible.

As another example of a conventional method and apparatus for producing a single crystal, a method and apparatus for producing a compound semiconductor single crystal are disclosed, for example, in Japanese Patent Application Laid-Open No. 63-270379.

In this method and apparatus, Ga and A
After directly synthesizing GaAs with the seed crystal, the seed crystal is pushed up from below, and the liquid stopper on the seed crystal is released into the melt to float on the melt surface, thereby bringing the seed crystal into contact with the melt to form GaAs. A single crystal is growing.

As still another example of the conventional method and apparatus for producing a single crystal, Japanese Patent Application Laid-Open No. 63-74990 discloses a method and apparatus for producing a compound semiconductor single crystal.

In this method and apparatus, the crucible uses G
After directly synthesizing a and As, the sealing at the top of the seed crystal is released, and the melt of the compound semiconductor and the seed crystal are brought into contact with each other to form GaAs.
An s single crystal is grown.

[0008]

However, the prior art disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-13098 has the following problems.

That is, when the temperature is raised, the raw material A in the upper layer in the crucible easily combines with the high-dissociation pressure raw material B in the lower layer in the crucible more easily than reacts with the vapor component of the raw material B from the lower part of the growth vessel. . Therefore, the raw material B in the lower layer is destroyed, and the raw material A in the upper layer in the crucible contacts the seed crystal, thereby damaging the seed crystal. That is, the liquid material in the upper layer in the crucible is
There is a problem that the seed crystal easily reaches the seed crystal through the gap between the lower layer raw materials and damages the seed crystal.

Further, in this technique, it is necessary to cover the upper portion of the seed crystal with a dense raw material B having exactly the same shape as the inner surface of the crucible so that the raw material before synthesis does not damage the seed crystal. However, it is extremely difficult to densely fill the raw material B of the high dissociation pressure component element with the shape of the crucible, and even if it can be manufactured by molding, there is also a problem that the cost becomes extremely high. Was.

Further, the above-mentioned Japanese Patent Application Laid-Open No. 63-270379
The prior art disclosed in Japanese Patent Application Laid-Open Publication No. H10-15095 has the following problems.

That is, since a mechanism for accurately moving the seed crystal up and down is required, the structure of the furnace is complicated, resulting in a problem that the cost is increased.

Further, in this technique, in order to prevent the raw material before synthesis from damaging the seed crystal, it is necessary to strongly adhere a precisely shaped liquid stopper to the crucible so that no gap is formed. . As a result, the seed crystal is subjected to a compressive force at a high temperature, so that the seed crystal is damaged and single crystal growth becomes difficult,
There was also a problem that the yield of single crystal production was reduced.

Further, the above-mentioned Japanese Patent Application Laid-Open No. 63-74990 is described.
The prior art disclosed in Japanese Patent Application Laid-Open Publication No. H10-15095 has the following problems.

That is, also in this technique, in order to prevent the raw material before synthesis from damaging the seed crystal, it is necessary to tightly attach a precisely shaped liquid stopper to the crucible so that no gap is formed. . Therefore, there is a need for a mechanism for accurately setting the sealing means above the seed crystal, resulting in a problem that the structure of the furnace is complicated and the cost is high. In addition, there is a problem that the sealing means needs to be in strong contact with the crucible, and the crucible is easily damaged.

An object of the present invention is to solve the above-mentioned problems and to improve the yield of single crystal growth by preventing the raw material before synthesis from reacting with the seed crystal to damage the single crystal. To provide a method for producing a single crystal.

Still another object of the present invention is to provide a single crystal manufacturing apparatus having a more simplified structure for carrying out the above-described method.

[0018]

An apparatus for producing a single crystal according to the present invention is provided with a first container for accommodating a seed crystal and growing the single crystal and surrounding the first container. Heating means, and a second vessel above the first vessel, having an opening at the bottom, and containing a raw material for growing a single crystal, wherein the second vessel comprises: Including a sealing means that is detachable and seals the opening.

The single crystal manufacturing apparatus according to the second aspect of the present invention
In the configuration of the first aspect of the present invention, the first container has a seed crystal storage portion at the bottom portion, the sealing means has a convex shape portion, and is tightly attached to the opening from the inside of the second container. Then, the opening is sealed.

The single crystal manufacturing apparatus according to the invention of claim 3 is
In the structure of the second aspect of the present invention, the sealing of the opening is released by the pressure applied to the convex-shaped portion of the sealing means, whereby the sealing means is detached into the second container.

According to a fourth aspect of the present invention, there is provided a single crystal manufacturing apparatus comprising:
In the structure of the third aspect of the invention, the sealing means is a liquid stopper, and the seed crystal is stored in the seed crystal storage portion of the first container before the start of the single crystal growth, and A crystal containing an element corresponding to the elemental composition of the single crystal is accommodated in the upper portion of the seed crystal, and a raw material for growing the single crystal is accommodated in the second container sealed by the sealing means. , Second
After the raw material melt having the composition corresponding to the composition of the single crystal is synthesized in the container of the above, at the start of the single crystal growth, the relative position between the first container and the second container is changed to obtain the liquid. The sealing of the opening is released by bringing the convex-shaped portion of the stopper plug into contact with the crystal, and the raw material melt is brought into contact with the seed crystal,
The raw material melt is solidified from the contact portion.

A single crystal manufacturing apparatus according to a fifth aspect of the present invention
In the structure of the second aspect of the invention, the sealing of the opening is released by the detachment of the sealing means into the second container by mechanical force.

A single crystal manufacturing apparatus according to the invention of claim 6 is
In any one of claims 1 to 5,
The single crystal is a III-V group compound semiconductor or II-V
It is a group I compound semiconductor single crystal.

[0024] In the method for producing a single crystal according to the invention of claim 7, a step of accommodating a seed crystal in a bottom portion of the first container;
A raw material for growing a single crystal in a second container having an opening at the bottom above the first container and having a detachable sealing means for sealing the opening. And the step of synthesizing a raw material melt having a composition corresponding to the composition of the single crystal in the second container, and releasing the sealing of the opening by removing the sealing means from the opening. And contacting the raw material melt with the seed crystal, and solidifying the raw material melt from a portion in contact with the seed crystal.

The method for producing a single crystal according to the invention of claim 8 is as follows:
The structure of the invention according to claim 7, wherein the sealing means is a liquid stopper, and further comprising a step of housing a crystal containing an element corresponding to the elemental composition of the single crystal on the seed crystal in the first container. The detachment of the sealing means from the opening is performed by changing the relative position between the first container and the second container, thereby bringing the liquid stopper into contact with the crystal.

The method for producing a single crystal according to the ninth aspect of the present invention comprises:
In the configuration of the invention according to claim 7, the sealing means is a liquid stopper, and detachment of the sealing means from the opening is performed by mechanical force.

According to a tenth aspect of the present invention, there is provided a method of manufacturing a single crystal according to any one of the seventh to ninth aspects, wherein the single crystal is a group III-V compound semiconductor or II.
-It is a group VI compound semiconductor single crystal.

[0028]

(Embodiment 1) FIG. 1 is a sectional view showing a schematic configuration of an example of a single crystal manufacturing apparatus according to the present invention.

Referring to FIG. 1, this single crystal manufacturing apparatus comprises:
A first container 8 for accommodating a seed crystal 9 and growing a single crystal in the high-pressure chamber 1, a second container 3 for accommodating a raw material 4 for growing the single crystal, and a first container 8. A heater 12 provided to surround the container 8.

The first container 8 has a concave portion for storing the seed crystal 9 at the bottom, and is mounted on the lower shaft 16. The second container 3 has an opening 6 above the first container 8 at the tip of the tapered portion at the bottom.

This opening 6 is sealed by a liquid stopper 7. The liquid stopper 7 has a convex shape portion and is in close contact with the opening 6 from the inside of the second container 3. in this way,
The opening 6 is sealed by the liquid stopper 7 so that the raw material 4 in the second container 3 does not leak out.

On the seed crystal 9 in the first container 8, B ₂
A sealing material 5 such as O ₃ and a crystal 11 containing an element corresponding to the elemental composition of the single crystal are accommodated. Note that this crystal 1
1 may be a polycrystal or a single crystal. As will be described later, the crystal 11 acts when the liquid stopper 7 is released from the opening 6 of the second container 3, and the raw material 4 leaking from the second container 3 comes into contact with the seed crystal 9. And protects the seed crystal 9. Further, it is desirable that crystal 11 be sufficiently covered with sealing material 5.

On the other hand, the raw material 4 contained in the second container 3
A sealing material 5 such as B ₂ O ₃ is also accommodated in the upper part of FIG.

In this embodiment, an airtight reservoir 2 is inserted in the second container 3. A second raw material 14 of a volatile element is accommodated in the airtight reservoir 2, and a raw material gas is supplied into the second container 3 via a volatile element gas introduction pipe 15. Therefore, in this embodiment, first, only the non-volatile first raw material 4 is stored in the second container 3.

Next, a method of manufacturing a crystal using the crystal manufacturing apparatus configured as described above will be described.

FIG. 2 is a cross-sectional view for explaining an example of the crystal manufacturing method according to the present invention, and is a view showing a method of manufacturing a crystal using the crystal manufacturing apparatus shown in FIG.

In FIG. 2, the high-pressure chamber 1 and the heater 12 in FIG. 1 are omitted.

First, referring to FIG. 2A, a seed crystal 9 is accommodated in the bottom of a first vessel 8 placed on a lower shaft 16, and B ₂ O ₃ or the like is further placed thereon. Sealing material 5 and crystal 1
Accommodates one. The second container 3 has a bottom opening 6 sealed with a liquid stopper 7 and then a non-volatile first raw material 4.
And a sealing material such as B ₂ O ₃ is further housed thereon. This first raw material 4 contains a second raw material 14 of a volatile element.
Is inserted into the volatile element gas introduction pipe 15 of the airtight reservoir 2 containing the gas.

In this state, heating is performed by the heater 12 and the airtight reservoir 2 is introduced into the first raw material 4 contained in the second container 3 through the volatile element gas introduction pipe 15.
The gas of the second raw material 14 housed therein is introduced to synthesize both elements. As a result, as shown in FIG. 2B, a synthetic raw material melt 13 is formed in the second container 3.

When the synthesis of the raw material melt 13 is completed, as shown in FIG.
The sealing of the opening 6 is released by bringing the convex-shaped portion of FIG.

Here, in this embodiment, the liquid stopper 7 is made of a material which is lighter than the synthetic raw material melt 13 and which does not react with the synthetic raw material melt 13. Therefore, as shown in FIG. 2D, the liquid stopper 7 floats on the surface of the synthetic raw material melt 13, and the synthetic raw material melt 13 in the second container 3 passes through the opening 6 to the first synthetic raw material melt 13. It flows into the container 8.

At this time, if the opening 6 of the second container 3 is covered with the sealing material 5, the surface of the synthetic raw material melt 13 flowing out into the first container 8 is also covered with the sealing material 5. Will be Thereafter, the temperature inside the first vessel 8 is gradually raised to melt the crystal 11 and melt to the upper end of the seed crystal 9, and then the lower shaft 16 is gradually lowered as shown in FIG. The single crystal 17 is grown from the seed crystal 9.

In FIGS. 1 and 2, for simplicity, a jig for fixing the airtight reservoir 2 and the second container 3 and the like in a space, a heat insulating material around the heater 12 and a lower portion of the airtight reservoir 2 are shown. Etc. are omitted. The airtight reservoir 2 and the second container 3 can be made to penetrate the upper shaft from the outside of the high-pressure chamber 1 and fixed to the upper shaft so as to be able to move up and down so as to function more actively.

Further, the first container 8 and the second container 3 are surrounded by an airtight container, and the second raw material 14 of the volatile element is arranged inside the airtight container and filled with the volatile element, thereby obtaining the first container. It is not necessary to use the liquid sealing material 5 in the container 8 and the second container 3.

In the present embodiment, in order to accommodate the second raw material 14 of the volatile element, the airtight reservoir 2 is made of airtight carbon, pBN-coated carbon, S
It can be made of iC, quartz, or a composite material thereof. A resilient carbon sheet may be used for the connection part when composed of a composite material. Meanwhile, the first
The container 8 and the second container 3 can be configured using pBN, quartz, carbon, or a composite material thereof.

The form of the sealing means for sealing the opening 6 at the bottom of the second container 3 may be any structure as long as the synthetic raw material melt 13 in the second container 3 does not leak. Various forms are conceivable. For example, even if the liquid stopper plug 7 itself does not have a convex-shaped portion and is flat, even if the crystal 11
A projection can be provided instead.

Various methods can be considered for removing the liquid stopper 7 from the opening 6 of the second container 3. For example, it is also possible to provide a means for pulling up the liquid stopper 7 upward, and to detach the liquid stopper 7 from the opening 6 by mechanical force using this means.

Further, in this embodiment, the relative position between the first container 8 and the second container 3 is changed by raising the first container 8, but the second container 3 is moved down. By doing so, the relative position between the first container 8 and the second container 3 can be changed. Therefore, in the present embodiment, it is sufficient that at least one of the first container 8 and the second container 3 is movable.

(Embodiment 2) FIG. 3 is a cross-sectional view for explaining another example of the single crystal manufacturing method according to the present invention.
In FIG. 3, as in FIG.
The heater 12 and the heater 12 are omitted.

In the method according to the second embodiment shown in FIG. 3, the raw materials 4 and 14 of the two elements are both housed in the second container 3 without using the airtight reservoir 2, and the direct synthesis is performed. The method is different from the method of the first embodiment shown in FIG.

This method is particularly effective when all the raw materials before synthesis are made of materials containing no volatile elements.

The other points are completely the same as those in the method of the first embodiment shown in FIG.

(Embodiment 3) FIG. 4 is a sectional view showing a schematic configuration of still another example of a single crystal manufacturing apparatus according to the present invention.

Referring to FIG. 4, this single crystal manufacturing apparatus
A high-pressure water cooling chamber 22 and a core tube 10 are provided.

The inside of the high-pressure water cooling chamber 22 is separated by the furnace tube 10 into a heater area 31 including the heater 13 and a growth area 32 in which crystal growth is performed.

In the heater area 31, in addition to the heater 13, a heat insulating material 20 and a heater electrode 21 are arranged. The heater area 31 is provided with a heater area gas inlet 24 and a heater area gas outlet 23. On the other hand, in the growth region 32, a first container 8 and a second container 3 similar to those in the apparatus of the first embodiment shown in FIG. The growth zone 32 is provided with a growth zone gas inlet 29 and a growth zone gas outlet 28.

In this single crystal manufacturing apparatus, the heater 13
Is a heater in which a temperature distribution zone of three or more zones is formed in a vertical type, and a plastically deformable material is used as a resistance heating element. Therefore, the structure of the furnace becomes simple, and a multi-zone temperature distribution zone can be formed at low cost. As the plastically deformable material, for example, an alloy mainly containing iron-chromium-aluminum, an alloy mainly containing nickel-chromium, an alloy mainly containing nickel-chromium-iron, or the like can be used.

On the other hand, such a plastically deformable material is
In general, since a metal is contained, when a heater made of such a material is used, there is a problem that the metal is mixed as an impurity into a manufactured crystal. Thus, in this apparatus, the heater region 31 and the growth region 32 are separated by the core tube 10. As a result, contamination of the produced crystal with impurities is effectively prevented. further,
The furnace tube 10 also serves to prevent the heater 13 from deteriorating in order to prevent the vapor of volatile components in the crystal to be manufactured from coming into direct contact with the heater 13.

When the heater region 31 and the growth region 32 are separated as described above, if the pressure difference between the heater region 31 and the growth region 32 becomes too large, the airtight container 22 may be damaged. . Therefore, the single crystal manufacturing apparatus according to this embodiment further includes a pressure balance mechanism for controlling the difference between the gas pressure in heater region 31 and the gas pressure in growth region 32 so as not to exceed a predetermined value. Have.

More specifically, this single crystal manufacturing apparatus includes a heater zone gas pressure sensor 25 for measuring the pressure in the heater zone 31 and a growth zone for measuring the pressure in the growth zone 32 as a pressure balance mechanism. And a gas pressure sensor 27. The gas pressure in the heater area measured by the heater area gas pressure sensor 25 is transmitted as a pressure sensor signal 26 to the heater area gas inlet 24 as shown by the arrow. On the other hand, the gas pressure in the growth area measured by the growth area gas pressure sensor 27 is transmitted as a pressure sensor signal 30 to the growth area gas inlet 29 as shown by the arrow.

An oxidizing gas such as air is used as a heater zone gas, and N ₂ gas is used as a growth zone gas.
When the main components of the gas in the heater region 31 and the growth region 32 are different from each other as in the case of using a non-oxidizing gas such as Ar or Ar, a pressure sensor 25 attached to each region as a pressure balance mechanism, A structure capable of adjusting each gas pressure can be produced electrically or mechanically so that the difference of 27 does not become larger than a certain value. On the other hand, heater area 3
When the main component of the gas in the growth region 32 may be the same as that in the growth region 32,
As a pressure balance mechanism, the airtight core tube 10 500
It is also possible to use a structure in which a small hole is formed in a portion at a temperature of not more than ° C. That is, the part to be perforated is 500 ° C
By doing so, it is possible to prevent the heater 13 from deteriorating due to the raw material vapor and from contaminating impurities from the heater 13 to the raw material. When the pressure is low, the wall of the hermetic container 22 is limited to the growth region 32 only, and the wall of the hermetic container 22 of the heater region 31 is eliminated, so that the heater region 31 is set to the atmospheric pressure atmosphere and the pressure in the furnace tube 10 is reduced. It is also possible to have a structure that gives

Further, in this single crystal manufacturing apparatus, the heater 13 is made of an alloy mainly composed of iron-chromium-aluminum, an alloy mainly composed of nickel-chromium, an alloy mainly composed of nickel-chromium, Nickel-chromium-
When a resistance heating element made of an alloy containing iron as a main component is used, it is preferable that the gas in the heater region 31 be oxidizing gas such as air. This is because the heater 13 can be prevented from deteriorating and its life can be extended, so that the crystal manufacturing cost can be further reduced.

In this single crystal manufacturing apparatus, the material of the furnace tube 10 is quartz, silicon carbide, aluminum oxide, silicon nitride, aluminum nitride, or carbon, or any of these as a base material. It is preferable to use a composite material coated with an oxidation-resistant or dense material. By using such a material, it is possible to easily achieve high purity of the manufactured crystal and prevention of deterioration of the heater.

The other configuration is exactly the same as that of the single crystal manufacturing apparatus according to the first embodiment shown in FIG. 1, and the description thereof is omitted.

Using the single crystal manufacturing apparatus configured as described above, single crystal growth is performed in the same manner as in the method of the first embodiment shown in FIG.

[0066]

(Example 1) An InP single crystal was manufactured by the method shown in FIG. 2 using the single crystal manufacturing apparatus of the first embodiment shown in FIG.

First, referring to FIG. 1 and FIG.
The pressure inside the high-pressure chamber 1 was set to 40 atm of Ar gas, and 7.6 kg of P was charged into the airtight reservoir 2. The second container 3 is made of quartz having a diameter of a straight body of 60 mm, and contains 2 kg of In as a first raw material 4 therein.
80 g of B ₂ O ₃ was charged as the sealing material 5. An opening 6 having a diameter of 10 mm provided at the end of the tapered portion at the bottom was filled with a liquid stopper 7 made of quartz having a convex shape so as to prevent the In solution 4 from leaking outside. On the other hand, a seed crystal 9 is accommodated in the bottom of a first vessel 8 made of quartz having a diameter of a straight body of 80 mm, and 100 g of B ₂ O ₃ as a sealing material 5 and InP 200 g of polycrystalline 11
And doping material (S concentration is 1 × 10 ¹⁸ c
(designed as m ⁻³ ). First
The InP polycrystal 11 in the container 8 prevents the In liquid 4 leaking from the inside of the second container 3 from coming into contact with the seed crystal 9 and also serves to protect the seed crystal 9. Further, B ₂ O ₃ as the sealing material 5 is inserted so as to sufficiently cover the InP polycrystal 11.

In this state, the heater 12 is heated so that the temperature of the raw material 4 in the second container 3 is about 1080 ° C.
The temperature of the airtight reservoir 2 is raised to 500 ° C. or higher while the temperature below the sealing material 5 is maintained at 1050 ° C. or lower,
As shown in FIG. 2B, In as the first raw material 4 and P as the second raw material 14 were synthesized in the second container 3.

When the synthesis of the InP synthesis raw material melt 13 is completed, the lower shaft 16 is raised as shown in FIG.
The convex-shaped portion of the liquid stopper 7 packed in the opening 6 at the bottom of the container 3 is brought into contact with the polycrystal 11 in the first container 8,
The liquid stopper 7 was removed.

As a result, as shown in FIG. 2D, the liquid stopper 7 floats on the surface of the synthetic raw material melt 13 by buoyancy, and the InP synthetic raw material melt 13 in the second container 3 is moved to the first position. It flowed into the container 8. At this time, the opening 6 at the bottom of the second container 3
Is covered with the sealing material 5, so that the surface of the synthetic raw material melt 13 in the second container 3 is covered with the sealing material 5. Thereafter, the temperature inside the first container 8 is gradually increased,
After being melted to the upper end of the seed crystal 9, as shown in FIG. 2 (e), the first container 8 is gradually lowered at a speed of 8 mm / hour to remove the InP single crystal 17 from the seed crystal 9 portion. I grew up.

As a result of performing such an experiment three times, an InP single crystal having a diameter of 3 inches was obtained, and the yield was 60% or more. The obtained crystals had a purity of 1 × 1 except for S.
It was 0 ¹⁵ cm ^-3 or less, and the EPD was extremely good with an average of 500 cm ^-2 or less.

(Example 2) A GaAs single crystal was manufactured by the method described in the second embodiment shown in FIG.

First, referring to FIG. 3A, the pressure in the high pressure chamber 1 was set to 50 atm. The second container 3 is made of pBN having a diameter of a straight body of 80 mm, and contains 5 kg of Ga as the first raw material 4 and A as the second raw material 14.
5.5 kg and 100 g of B ₂ O ₃ as the sealing material 5
And charged. An opening 6 having a diameter of 10 mm provided at the tip of the tapered portion at the bottom is filled with a liquid stopper 7 made of pBN-coated carbon having a convex shape.
Liquid a was prevented from leaking out. On the other hand, the bottom of the first container 8 diameter of the straight body portion is made of pBN of 105 mm, accommodating a seed crystal 9, in its upper part, B ₂ O as the sealing material 5
₃ and 200 g of the GaAs single crystal 11 were accommodated.

In this state, the heater 12 is heated, and the temperature of the raw material 4 in the second container 3 is gradually increased, and as shown in FIG. Was synthesized from Ga as the raw material 4 and As as the second raw material 14.

When the temperature in the second container 3 reaches 1150 ° C. and the synthesis of the GaAs synthesis raw material melt 13 is completed, FIG.
As shown in (c), the lower shaft 16 is raised and the second container 3
The convex-shaped part of the liquid stopper 7 filled in the opening 6 at the bottom of the container was brought into contact with the single crystal 11 in the first container 8 and the liquid stopper 7 was pulled out.

As a result, as shown in FIG. 3D, the liquid stopper 7 floats on the surface of the synthetic raw material melt 13 by buoyancy, and the GaAs synthetic raw material melt 13 in the second container 3 becomes the first synthetic raw material melt 13. It flowed into the container 8.

Then, the temperature inside the first container 8 is gradually increased to melt the seed crystal 9 up to the upper end portion.
As shown in (e), the first container 8 was gradually lowered at a speed of 10 mm / hour to grow the single crystal 17 from the seed crystal 9 portion.

As a result of performing such an experiment six times, Ga
As single crystal was obtained, and the yield was 70% or more. The obtained crystals had a purity of 1 × 10 ¹⁵ cm ⁻³ except for C.
Or less, and the EPD was extremely good with an average of 1000 cm ^-2 or less.

[0079]

As described above, in the conventional single crystal manufacturing apparatus and method, since the container for accommodating the raw material and the container for growing the crystal are the same container, the raw material before the synthesis is a seed crystal. A precise mechanism was needed to protect the seed crystal so as not to damage it. For example, in the case of GaAs, since the GaAs seed crystal reacts and melts at a low temperature when it comes into contact with liquid Ga before synthesis, the upper portion of the seed crystal is covered with a dense As material having the same shape as the inner surface of the crucible, or A mechanism was required to tightly attach a precisely shaped liquid stopper to the crucible so that no gap was formed between the crucible and the liquid stopper.
On the other hand, according to the first or seventh aspect of the present invention, the second container containing the raw material before the synthesis is different from the first container containing the seed crystal. Therefore, it is easy and reliable to seal the raw material before synthesis from flowing out of the second container. As a result, as an apparatus and a method for simultaneously performing the synthesis of the raw material and the crystal growth, it is possible to prevent the raw material before the synthesis from reacting with the seed crystal to damage the single crystal and improve the yield of crystal growth. it can.

Further, claims 2 to 5 or claim 8
According to the ninth to ninth aspects of the present invention, single crystal growth can be performed more reliably with a simplified structure and method.

In particular, according to the invention of claim 4 or claim 8, even if the raw material before synthesis slightly flows out of the second container, the crystal is arranged above the seed crystal in the first container. Therefore, the seed crystal can be easily protected. Therefore, the yield of single crystal growth can be significantly improved.

The present invention also provides a simpler and more effective method for sealing liquid materials before synthesis than conventional techniques.
It is particularly effective when used for the production of a single crystal of a compound containing a low-melting element such as a -V group compound semiconductor or a II-VI group compound semiconductor.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of an example of a single crystal manufacturing apparatus according to the present invention.

FIG. 2 is a cross-sectional view for explaining an example of a single crystal manufacturing method according to the present invention.

FIG. 3 is a cross-sectional view for explaining another example of the method for producing a single crystal according to the present invention.

FIG. 4 is a sectional view showing a schematic configuration of still another example of the single crystal manufacturing apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 22 High-pressure chamber 2 Airtight reservoir 3 2nd container 4 1st raw material 5 Sealing material 6 Opening 7 Liquid stopper 8 1st container 9 Seed crystal 11 Crystal 12 Heater 13 Synthetic raw material melt 14 2nd raw material 15 Volatile element gas introduction pipe 16 Lower axis In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (10)

[Claims] 1. A single crystal manufacturing apparatus, comprising: a first container for accommodating a seed crystal and growing a single crystal; a heating unit provided to surround the first container; Above the one container, having an opening at the bottom,
A second container for accommodating a raw material for growing the single crystal, wherein the second container is detachable and includes sealing means for sealing the opening. Single crystal manufacturing equipment. 2. The first container has a storage portion for the seed crystal at a bottom portion, the sealing means has a convex-shaped portion, and the first container has an opening from the inside of the second container. The apparatus for producing a single crystal according to claim 1, wherein the opening is tightly sealed to seal the opening. 3. The sealing of the opening is released by detaching the sealing means into the second container by a pressure applied to the convex-shaped portion of the sealing means. The single crystal manufacturing apparatus according to claim 2. 4. The method according to claim 1, wherein the sealing unit is a liquid stopper, and the seed crystal is stored in a storage portion of the seed crystal in the first container before the start of the single crystal growth. A crystal containing an element corresponding to the elemental composition of the single crystal is accommodated in the upper portion of the seed crystal in the container, and in the second container sealed by the sealing means,
A raw material for growing the single crystal is accommodated, and a raw material melt having a composition corresponding to the composition of the single crystal is synthesized in the second container. By changing the relative position between the first container and the second container, the sealing of the opening is released by bringing the convex-shaped portion of the liquid stopper into contact with the crystal, and the raw material is removed. The single crystal production apparatus according to claim 3, wherein the melt is brought into contact with the seed crystal, and the raw material melt is solidified from a contact portion. 5. The method according to claim 5, wherein the sealing means is provided with the second force by a mechanical force.
The single crystal production apparatus according to claim 2, wherein the sealing of the opening is released by detaching the opening into the container. 6. The single crystal is a III-V group compound semiconductor or a II-VI group compound semiconductor single crystal.
The single crystal production apparatus according to claim 1. 7. A method for producing a single crystal, comprising the steps of: accommodating a seed crystal in a bottom of a first container; and having an opening in a bottom above the first container, wherein the opening is detachable. Accommodating a raw material for growing the single crystal in a second container including a sealing means for sealing the opening; and converting the composition of the single crystal into the second container in the second container. Synthesizing a raw material melt having a corresponding composition, and removing the sealing means from the opening to release the sealing of the opening, thereby bringing the raw material melt into contact with the seed crystal. And a step of solidifying the raw material melt from a portion in contact with the seed crystal. 8. The method according to claim 1, wherein the sealing means is a liquid stopper, and further comprising: storing a crystal containing an element corresponding to the elemental composition of the single crystal in the upper part of the seed crystal in the first container. The detachment of the sealing means from the opening is performed by changing a relative position between the first container and the second container, thereby bringing the liquid stopper into contact with the crystal. The method for producing a single crystal according to claim 7, which is performed. 9. The method for producing a single crystal according to claim 7, wherein said sealing means is a liquid stopper, and said detachment of said sealing means from said opening is performed by mechanical force. 10. The method for producing a single crystal according to claim 7, wherein the single crystal is a III-V group compound semiconductor or a II-VI group compound semiconductor single crystal.