JPH0959090A - Production of chemical single crystal and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To directly form a vapor atmosphere of a high dissociation pressure component and obtain a good-quality single crystal having a desired composition from a raw material melt by providing a vapor source-housing container for housing a high dissociation pressure component in an upper position than a raw material housing container and carrying out growth of the single crystal while carrying out temperature control by independently heating a reserver separately from a heating area for heating the vapor source housing container. SOLUTION: The figure exhibits a single crystal producing apparatus by vertical Bridgeman method. A vapor source housing container 14 for housing a high dissociation pressure component 19 is arranged in an upper part of a crucible 13 arranged in an airtight chamber 15 and vapor for forming vapor atmosphere for suppressing dissociation of the raw material in the crucible 13 is generated and a laser bar 17 is provided below the crucible 13 and the heating temperature is controlled and vapor pressure generated in the vapor source housing container 14 is controlled so as not to become too high. Thereby, the vapor pressure is immediately controlled to that of a prescribed vapor atmosphere to efficiently produce good-quality single crystal having the desired composition.

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 compound single crystal in which a part of constituent elements is easily dissociated to evaporate at high temperature during crystal growth.

[0002]

2. Description of the Related Art Liquid-encapsulated Czochralski method (LEC) is used for the production of compound single crystals in which specific components are easily dissociated and evaporated.
Method), horizontal Bridgman method (HB method), vertical Bridgman method (VB method), vertical temperature gradient solidification method (VGF method), etc. are used. Among them, the VB method and the VGF method have been greatly expected as an industrial production method because they can produce a relatively large-sized single crystal of good quality with few dislocations.

However, in many compound single crystal materials, a particular component dissociates and evaporates at a high temperature in the process of crystal growth in which the raw material is heated and melted and then the melt is solidified. Cause For example II-VI
ZnSe, which is a compound semiconductor of the group III, has a unique problem that Zn of the constituent elements easily evaporates, and the composition of the single crystal thus formed is deviated, so that the desired single crystal cannot be obtained.

Therefore, a manufacturing method for suppressing the transpiration due to the dissociation as described above has been conventionally proposed. For example, Japanese Patent Laid-Open No. 63-274784 discloses a pressure vessel as a furnace body as shown in FIG. An apparatus is disclosed in which a crucible 52 disposed inside the crucible 51 is further provided with a reservoir 53 for generating vapor of a high dissociation pressure component, below the crucible 52. When crystal growth is performed by containing, for example, a polycrystalline raw material 54 of GaAs which is a III-V group compound semiconductor in the crucible 52, As of the V group element is contained as a high dissociation pressure component 55 in the reservoir 53. . The crucible 52 and the reservoir 53 are housed in a cylindrical growth container 56 whose lower part is closed, and set in the pressure container 51. The crucible support base 57 between the crucible 52 and the reservoir 53 is made of, for example, a porous material having air permeability. Also, the growth container
The lid 58 that closes the upper opening of the 55 has an upper shaft 59 that raises and lowers it.
Are connected.

In the above apparatus, first, the gas in the pressure vessel 51 is replaced. This is a lid operated by operating the upper shaft 59.
With 58 raised, with the upper end of growth vessel 56 open,
The pressure vessel 51 is evacuated and then filled with an inert gas such as argon gas to pressurize the pressure vessel 51 to several atmospheres to 100 atmospheres. After that, operate the upper shaft 59 to lower the lid 58, and with the upper opening of the growth container 56 closed,
The heating by the main heater 60 is started and the polycrystalline raw material 54 is melted. At this time, the sub-heater 61 also heats the high dissociation pressure component 55 in the reservoir 53, and the vapor generated thereby adjusts the vapor pressure of the group V element in the growth vessel 56. As a result, dissociation and scattering of the group V element from the melted polycrystalline raw material 54 is suppressed.

In this state, by operating the lower shaft 62, the growth vessel 56 is lowered, the crucible 52 is gradually moved to a low temperature region, and the raw material melt in the crucible 52 is solidified.
A single crystal grows. Incidentally, in recent years, the above-mentioned ZnSe is considered promising for the production of blue light-emitting elements, and the production and development of its single crystal are being actively pursued. When the above-described reservoir is provided to control the vapor pressure in the production of the II-VI group ZnSe single crystal, it is not the anion element in the III-V group, but the cation element, that is, the group II Zn. It is common practice to control the vapor pressure of the. This is because in the case of ZnSe, both Zn and Se have higher vapor pressures at high temperatures, but Zn is more stable as an element, is easier to handle, and has a volume-specific characteristic that is one of the electrical characteristics of single crystals. This is due to the fact that it is easy to control in order to manufacture a conductive substrate by lowering the resistance.

[0007]

However, as described in the above publication, a reservoir 53 is provided below the crucible 52, and the vapor pressure of the surface of the raw material melt in the crucible 52 is controlled by the vapor generated therebelow. However, there is a problem that the dissociative evaporation of the raw material cannot be sufficiently suppressed.

Taking the case of ZnSe as an example, the furnace is pre-filled with an inert gas such as argon gas, and the vapor pressure generating element (Zn in this case) is placed below the crucible in this state. When arranged, the generated vapor diffuses in a form in which it gradually rises upward from the lower part inside the growth vessel.
At this time, since the specific gravity of Zn vapor is high with respect to the high-pressure inert gas, it takes a long time for Zn vapor to reach the upper part of the crucible, and therefore, during normal crystal growth of, for example, several tens of hours. , Zn vapor does not reach the surroundings of the raw material melt in the crucible sufficiently and crystal growth occurs. As a result, a high dissociation pressure component evaporates from the raw material melt in the crucible, and a crystal having a different composition grows.

On the other hand, in the apparatus described in the above publication, the crucible 52 and the reservoir 53 are heated by the sealed growth container 56.
It is surrounded by the inside of 60 and 61 to form a control space for the vapor atmosphere of the high dissociation pressure component.In this case, when the equilibrium dissociation pressure of the high dissociation pressure component is high, the internal / external differential pressure is applied to the growth vessel 56. A large force based on will act. For this a growth vessel
There is also a problem that 56 is easily broken, and as a result, sufficient productivity cannot be obtained.

The present invention has been made in view of the above-mentioned conventional problems, and it is a method for producing a compound single crystal capable of efficiently producing a high quality single crystal by suppressing evaporation of raw material constituent elements during crystal growth. And to provide the device.

[0011]

In order to achieve the above-mentioned object, the method for producing a compound single crystal according to claim 1 of the present invention comprises a raw material container having an upper end opening containing a raw material for growing a single crystal, A method for producing a compound single crystal in which a single crystal is grown from a raw material melt by raising and lowering the temperature in a heating region having a higher temperature in a furnace filled with an inert gas, and at least one of raw material constituent elements The vapor source storage container for storing the high dissociation pressure component is provided above the raw material storage container, while the reservoir for storing the high dissociation pressure component is provided below the raw material storage container, and is heated together with the raw material storage container in the heating region. Is to generate a vapor of at least a high dissociation pressure component from the vapor source storage container, and to adjust the vapor pressure of the high dissociation pressure component around the raw material storage container, the heating temperature in the heating region It is characterized by performing the single crystal growth while controlling the temperature to stand.

According to such a manufacturing method, for example, ZnSe
When manufacturing a single crystal, Zn is stored in each of the vapor source storage container and the reservoir. In the furnace body, a heating region in which the temperature is higher than that in the lower part is formed, and in this heating region, a raw material storage container containing a raw material ZnSe for single crystal growth is arranged and the temperature is raised and lowered. At this time, the vapor source storage container is also heated at the same time as the raw material storage container, and Zn vapor is generated. And since this vapor source storage container is located above the raw material storage container, even if the generated Zn vapor is heavier than the inert gas filled in the furnace body, immediately around the raw material storage container is Zn. It becomes a steam atmosphere.

On the other hand, if the vapor pressure generated in the vapor source container is too high, it will melt into the raw material melt and become Zn rich, but the heating temperature in the reservoir will be adjusted to a predetermined vapor pressure. By doing so, the excess Zn vapor generated in the vapor source storage container flows downward and is condensed and captured in the reservoir portion. Therefore, the melt of the raw material in the raw material container is suppressed from being dissociated and the change in the composition such that it becomes rich in Zn is suppressed, so that the crystal growth of the intended composition is performed throughout.

As in the method for producing a compound single crystal according to claim 2, when a single crystal is grown by arranging a seed crystal at the lower end portion of the above-mentioned raw material container, the whole single crystal having a predetermined orientation is obtained. You can definitely grow. Further, as in the method for producing a compound single crystal according to claim 3, if a raw material having substantially the same composition as the raw material stored in the raw material storage container is stored in the vapor source storage container to perform single crystal growth, The dissociation in the storage container can be more reliably suppressed.

That is, in the heating region where a temperature gradient is provided and the temperature is raised and lowered, the vapor source storage container above the raw material storage container is always maintained at a higher temperature and the temperature is raised and lowered. As a result, the raw material contained in the vapor source container first starts to dissociate to generate steam. As a result, dissociation in the raw material container can be more reliably suppressed as compared with the case where the vapor pressure of some of the constituent elements is adjusted.

The apparatus for producing a compound single crystal for suitably carrying out the above-mentioned production method comprises, as described in claim 4, a hermetically sealed furnace body filled with an inert gas, and a furnace body located above the furnace body. Main heating means arranged in the furnace body to form a high-temperature heating region, a raw material storage container having an upper end opening which is arranged in the heating region while containing raw materials for single crystal growth,
A vapor source storage container that stores at least a high dissociation pressure component in the raw material constituent elements and is heated above the raw material storage container and heated in the heating region, and a raw material storage container that stores the high dissociation pressure component And a sub-heating means for heating the reservoir, a raw material storage container, a vapor source storage container, and a reservoir inside the main heating means, and a communication passage downwardly connecting the inside and the outside with each other. And an airtight chamber made of an airtight material.

According to this structure, since the airtight chamber surrounding the raw material storage container, the vapor source storage container, and the reservoir is provided with the communication passage that does not cause a pressure difference between the inside and the outside.
Even if the vapor pressure due to dissociation during heating is high, the force due to the pressure difference between the inside and the outside does not act on the airtight chamber. This prevents damage to the hermetic chamber. Moreover, part of the vapor flowing to the lower communication passage is deposited at this portion of the communication passage due to the low temperature state of the communication passage, and does not flow out of the airtight chamber. As a result, for example, the maintenance of the device for preventing the occurrence of a short circuit accident is facilitated, so that even a compound having a high dissociation pressure can more efficiently produce its single crystal.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] Next, an embodiment of the present invention will be described with reference to FIG. The figure shows the vertical Bridgman method (VB
Method), a single crystal manufacturing apparatus is shown.
A pressure vessel 1 as a furnace body having a pressure resistant structure, an upper closed heat insulating structure 2 housed inside the pressure vessel 1, and a plurality of upper and lower stages arranged inside thereof (two stages in the case of the figure) A main heater (main heating means) 3 including the cylindrical heater elements 3a and 3b, and a cylindrical sub-heater (sub-heating means) 4 arranged below the main heating heater 3. There is.

The pressure vessel 1 comprises a cylindrical pressure vessel body 5
And an upper lid 6 and a lower lid 7 which cover the upper and lower openings, respectively. The upper lid 6 is provided with a gas supply / discharge passage 8 for injecting an inert gas such as argon gas under pressure into the pressure vessel 1 and discharging the same. The lower lid 7 is
It is detachably attached to the lower opening of the pressure vessel main body 5 and airtightly attached by a seal ring 9.

At the center of the lower lid 7, a seal ring is attached.
A crucible elevating rod 11 is provided airtightly through the lower lid 7 by means of 10. The rod 11 is configured to be vertically movable by an external drive mechanism (not shown), and a substantially column-shaped crucible stand 12 is attached to the upper end of the crucible lifting rod 11. A crucible 13 as a raw material storage container is supported on the crucible base 12 in a substantially upright state.

The crucible 13 is made of, for example, p-BN, and a thin tube portion into which a rod-shaped seed crystal 18 described later is inserted at its lower end portion.
13a is provided, and the upper part is provided with a tapered portion 13b.
It is formed in a tubular shape having an inner diameter of 15 mm. And
A vapor source storage container 14 is provided on the open upper end surface of the crucible 13. The vapor source storage container 14 is formed in a ring shape along the upper edge of the crucible 13 and is configured to accommodate a vapor source 19 described later in an annular groove formed so as to open at the upper surface thereof. There is.

Further, inside the pressure vessel 1, inside the main heater 3 and the sub-heater 4, the airtight chamber 15 in the shape of an inverted cup that surrounds the entire vapor source storage container 14, the crucible 13 and the crucible table 12 is provided. Are placed in a state of being placed on the lower lid 7. The hermetic chamber 15 is made of a material having heat resistance and gas impermeability such as high melting point metal such as molybdenum or glassy carbon. Further, in a portion of the airtight chamber 15 near the lower lid 7 which is kept at a relatively low temperature, a pore-shaped communication passage 16 which communicates the inner and outer spaces of the airtight chamber 15 with each other is formed. The communication passage 16 prevents the pressure difference between the inside and the outside of the airtight chamber 15 from being generated, and thereby prevents the airtight chamber 15 from being damaged when the inside of the pressure container 1 is brought to a predetermined high pressure state.

The airtight chamber 15 has a thick wall below the step surface 15a so that the step surface 15a is formed at the height position between the main heater 3 and the sub heater 4 on the inner surface of the cylindrical portion. It is formed into a shape. And this thick part
An annular groove-shaped reservoir 17 recessed downward from the step surface 15a is formed in 15b, and a high dissociation pressure component 20 described later is accommodated in the reservoir 17. The sub-heater 4 is arranged in accordance with the height position of the high dissociation pressure component 20 in order to heat the high dissociation pressure component 20 contained in the reservoir 17.

The thick portion 15b is formed to have an inner diameter substantially the same as the outer diameter of the crucible base 12 described above, and is configured so that the crucible 12 can move up and down in a substantially fitted state in the thick portion 15b. Has been done. It should be noted that the crucible base 12 is formed with a communication hole 12a in the form of a small hole that penetrates the crucible base 12 in the vertical direction.
Through, the upper and lower spaces of the crucible stand 12 communicate with each other.

On the other hand, in the same figure, the crucible table 12 is shown in the highest position in the pressure vessel 1. In this state, the lower end side of the crucible table 12 is slightly more than the step surface 15a. It is located on the lower side. As a result, the lower space of the crucible base 12 and the upper space of the reservoir 17 are in communication with each other only through the fitting gap between the inner surface of the thick portion 15b and the outer surface of the crucible base 12, and the flow of gas through this gap is substantially blocked. It is configured to be.

In the above apparatus, the electric power supplied to the main heater 3 is adjusted so that the inside of the airtight chamber 15 is maintained at a predetermined temperature distribution in which the temperature is higher toward the top. Therefore, by raising and lowering the crucible raising / lowering rod 11 to change the height position of the crucible 13 in the airtight chamber 15, temperature control is performed when growing a single crystal from the raw material for growing a single crystal in the crucible 13. .

Next, a procedure for producing a ZnSe single crystal using the above apparatus and an example of the result will be described. First, after inserting a rod-shaped ZnSe seed crystal 18 into the thin tube portion 13a of the crucible 13, about 20 g of small ZnSe polycrystals produced by the CVD method of Phase Four Co. was used as a raw material for single crystal growth. Meanwhile, about 5 g of Zn as the vapor source 19 was filled in the vapor source storage container 14, and 10 g of Zn as the high dissociation pressure component 20 was filled in the reservoir 17 respectively.

The crucible 13 / vapor source storage container 14 and the airtight chamber 15 provided with the reservoir 17 are arranged in the pressure container 1 as shown in the figure to seal the pressure container 1 and then through the gas supply / discharge passage 8. The inside of the pressure vessel 1 was evacuated, and then 5 kgf / cm ² argon gas was injected to replace the gas. Then, after filling the pressure vessel 1 with 5 kgf / cm ² of argon gas, the heater element 3a
3b is energized, and the raw material and vapor source storage container 14 in the crucible 13
The heating of the steam source 19 inside was started. Then, the electric power supplied to the main heater 3 was controlled so that the upper part of the crucible 13 was 1580 ° C. and the lower part thereof was 1515 ° C., and the raw material was melted while leaving a part of the seed crystal 18. At this time, the pressure in the pressure vessel 1 was 10 kgf / cm ² .

On the other hand, at the same time when the main heater 3 is energized,
The high dissociation pressure component 20 in the reservoir 17 is also heated by the auxiliary heater 4
Started by, its heating temperature occurs in the reservoir 17
The vapor pressure of Zn vapor was adjusted to about 1000 ° C. so that the equilibrium vapor pressure of Zn vapor at the melting point of ZnSe (1520 ° C.) was about 2 atm. Then, the crucible lifting rod 11 is slowly lowered, and the crucible 13 is gradually lowered to a low temperature region at a rate of 3 mm / h at a temperature gradient of 20 ° C./cm, so that the seed crystal 18 in the raw material melt 21 is reduced. A single crystal 22 was grown from the lower side in contact with to the upper side.

In this way, in the course of the crystal growth operation of heating the raw material in the crucible 13 to a temperature exceeding the melting point of ZnSe and then lowering the temperature, dissociation of the raw material gradually progresses during the temperature rise.
At this time, in the above configuration, first, the upper vapor source storage container
Zn vapor is generated from 14, and since this Zn vapor is heavier than the argon gas filling the airtight chamber 15, it gradually descends and flows into the crucible 13. Therefore, when the raw material is melted, the Zn vapor atmosphere in which the dissociation of the ZnSe raw material is suppressed is already formed in the crucible 13.

At this time, if the vapor pressure of the Zn vapor generated from the vapor source container 14 is too high, the composition of the raw material melt 21 becomes Zn rich and the melting point is lowered, but the vapor of Zn is in the crucible 13 Since the outside also moves downward, if the temperature of the lower reservoir 17 is kept at 1000 ° C. as described above, excess Zn vapor is condensed and trapped in this reservoir 17. Therefore, in the crucible 13, since the dissociation of the raw material melt 21 is suppressed and the composition change such that the material becomes Zn-rich is suppressed and the atmosphere is maintained in the Zn vapor atmosphere, the entire material melt 21 is intended. The single crystal 22 having the above composition is grown.

The raw material melt in the crucible 13 is subjected to the above operation.
The entire 21 solidified, and the upper part of the crucible 13 was approximately 1300 ° C.
When, the main heater 3 and the sub-heater 4
Then, when the furnace was cooled down to about 300 ° C., the argon gas in the pressure vessel 1 was discharged to the outside of the furnace. Next, when the temperature dropped to about room temperature, the lower lid 7 was lowered, the pressure vessel 1 was opened, and the crucible 13 was recovered.

The grown crystal taken out from the crucible 13 has an outer diameter of about 15 mm, a straight body length of 20 mm, and a twin crystal in a part,
It was a yellow transparent single crystal that was considered as one grain as a whole. The weight change in the crucible 13 was 0.1% or less, and it was confirmed that the decomposition of the raw material ZnSe was sufficiently suppressed. For the purpose of investigating the change of Zn composition in the grown crystal, the grown crystal was sliced into a disk shape and the change in the volume resistivity in the vertical direction was measured. As a result, it was confirmed that the volume resistivity was 0.02 to 0.03 Ωcm at any part, and there was almost no variation in characteristics in the vertical direction, that is, there was little variation in composition.

Comparative Example Using the same apparatus as in the first embodiment, except that Zn is not filled in the vapor source storage container 14,
The ZnSe single crystal was grown in the same procedure as in the first embodiment. Although the obtained grown crystal did not show a large difference in color tone when observed with the naked eye, the volume resistivity was measured and it was found that the lower side near the seed crystal in the grown crystal.
A difference of 0.5 to 2 Ωcm and 0.04 Ωcm on the upper side were observed in the vertical direction. From this volume resistivity value, it was found that there was a compositional distribution in which the amount of Zn was low in the lower part and large in the upper part, and it was judged that it could not be used for substrates such as laser diodes because of inhomogeneity. Was done.

[Second Embodiment] Next, another embodiment of the present invention will be described with reference to FIG. For convenience of description, members having the same functions as the members shown in the first embodiment will be designated by the same reference numerals, and the description thereof will be omitted. The figure shows a single crystal manufacturing apparatus by the vertical temperature gradient solidification method (VGF) method.To control the temperature distribution in the vertical direction in the airtight chamber 15 more precisely, the single crystal production apparatus is provided outside the airtight chamber 15. A main heater 3 having upper and lower 10 heater elements 3a to 3j is provided. The pressure vessel 1 as a furnace body is formed in an upper closed shape, and the lower lid 7 is provided with a gas supply / discharge passage 8.

On the other hand, in the airtight chamber 15, a support base 31 is arranged on the bottom side thereof in a state of being placed on the lower lid 7. The sub-heater 4 is arranged on the support base 31, and the bottomed cylindrical inner container 32 is further provided on the sub-heater 4. Like the airtight chamber 15, the inner container 32 is made of a material having heat resistance and airtightness, such as a high melting point metal such as molybdenum or glassy carbon, and a high dissociation pressure component is formed at the bottom of the inner container 32. A reservoir 17 containing 20 is arranged. The crucible table 12 is placed on the upper end surface at the peripheral edge of the reservoir 17, and the crucible 13 is supported on the crucible table 12 in the upright state, as described above.

On the other hand, the side wall surface 32a of the inner container 32 is a crucible.
A vapor source housing container 14 for housing the vapor source 19 is attached to the upper end portion of the side wall surface 32a which is open and extends near the upper wall surface of the airtight chamber 15 beyond the upper end of 13. The airtight chamber in this embodiment
The communication passage 16 on the lower end side is formed by a gap formed between the lower cover 7 and the lower lid 7 by cutting out a part of the lower end edge. Also, the inner container 32
Is formed with an outer diameter dimension having a sufficient gap with the inner surface of the inner chamber 15, and the inside of the inner container 32 becomes a space outside the airtight chamber 15 through the communicating gap 33 and the communicating passage 16 therebetween. It is in communication.

An operation procedure for growing, for example, a ZnSe single crystal using the above apparatus will be described below. First, in the same manner as described above, a ZnSe seed crystal is applied to the thin tube portion 13a of the crucible 13.
18 is set, and a ZnSe polycrystal raw material is filled therein, and Zn is filled in the vapor source storage container 14 and the reservoir 17 as the vapor source 19 and the high dissociation pressure component 20, respectively.

Then, set the crucible 13 as shown in the figure,
Next, the gas inside the pressure vessel 1 is replaced by vacuuming and injecting argon gas, and then argon gas of several atmospheres to several tens of atmospheres is filled. After that, the heater elements 3a to 3j of the main heater 3 are energized to heat and melt the raw material while leaving the lower part of the seed crystal 18. At this time, the temperature is controlled so as to obtain a temperature distribution in which the higher the temperature, the higher the temperature distribution. On the other hand, the portion of the reservoir 17 has a temperature of about 1000 ° C. as described above.
The power supplied to the sub-heater 4 is adjusted.

By such temperature control, as in the above-described embodiment, Zn vapor is generated from the upper vapor source storage container 14, and this Zn vapor is heavier than the argon gas in the hermetic chamber 15, so that it is gradually lowered. Then, it flows into the crucible 13 and an atmosphere is formed in which the dissociation of the ZnSe raw material in the crucible 13 is suppressed. Moreover, excess Zn vapor is condensed and trapped in the lower reservoir 17.

As described above, by controlling the Zn vapor pressure and adjusting the electric power supplied to the heater elements 3a to 3j, the temperature of the entire furnace is gradually lowered while maintaining a predetermined temperature gradient. The first embodiment from the lower side of the crucible 13
Similar to the above, good quality ZnSe single crystal with suppressed composition deviation 22
Can grow. As described above, in each of the above-described embodiments, when the raw material in the crucible 13 is heated to produce a single crystal, first, the Zn vapor generated in the vapor source storage container 14 above the inside of the crucible 13 is used. An atmosphere is formed that suppresses dissociation of the ZnSe raw material. Moreover, since the compositional change such that the Zn vapor becomes excessive and the raw material melt becomes Zn-rich is also suppressed by the temperature control of the lower reservoir 17, a single crystal of good quality having the intended composition throughout the crucible 13 is suppressed. You can grow.

When it is desired to produce a Zn-rich single crystal with an excessive amount of Zn in the raw material melt, the amount of the vapor source 19 is increased and the temperature of the reservoir 17 is higher than 1000.degree. It can be achieved by adjusting the temperature. Therefore, in each of the above-described embodiments, it is possible to adjust the composition in the production of a compound single crystal having a high dissociation pressure, for example, in the case of a binary system, it is possible to reliably grow a single crystal having a composition of 1: 1. It is also possible to change the composition accurately. Moreover, it becomes easy to ensure the homogeneity of the whole single crystal,
The reproducibility of the composition is also good when the single crystal operation is repeated. As a result, it is possible to greatly simplify the industrial production of a single crystal in which variations in quality pose a problem.

Further, in each of the above embodiments, since the vapor source storage container 14 is provided in the heating region where a temperature gradient is provided and the temperature is raised and lowered, the vapor source storage container 14 is provided close to the upper part of the crucible 13. It is not necessary to control heating independently of the crucible 13, and this simplifies the overall configuration. Further, in each of the above embodiments, the airtight chamber 15 that surrounds the crucible 13 and the vapor source storage container 14 is provided with the communication passage 16 below the airtight chamber 15. Therefore, even if the vapor pressure due to dissociation during heating is high, the force due to the difference between the internal pressure and the external pressure does not act on the airtight chamber 15. As a result, since the airtight chamber 15 does not need to have high strength as long as it has heat resistance, it is easy to manufacture, and the selection range of materials is expanded. Is possible. Therefore, the single crystal excellent in quality can be manufactured also by this.

On the other hand, a part of the Zn vapor generated in the vapor source storage container 14 flows downward through the communication hole 12a formed in the crucible base 12 in the first embodiment, for example, and further in the airtight chamber 15. It will flow to the communication passage 16,
At this time, since the communication passage 16 is provided at a portion apart from the heaters 3 and 4 downward, by keeping this portion at a low temperature below the melting point of Zn, vapor is deposited at this portion. You can As a result, steam does not come into contact with the heaters 3 and 4 on the outside of the airtight chamber 15 and members for supplying electric power to the heaters 4, thereby preventing occurrence of a short circuit accident or the like. Further, if the entire inside of the furnace is contaminated by the diffused steam, a large amount of labor is required for maintenance work such as disassembling and cleaning the internal structure of the furnace as needed. Since diffusion throughout the furnace is suppressed, maintenance work is facilitated, thereby improving production efficiency.

In each of the above embodiments, an example was shown in which Zn constituting a part of the crystal growth raw material was stored in the vapor source storage container 14, but instead of this, the same raw material as the crystal growth raw material was stored. It is also possible to grow a single crystal while simultaneously generating vapors of Zn, Zn and Se. In this case, in the heating area where a temperature gradient is provided and the temperature is raised and lowered, the crucible is
The vapor source storage container 14 above 13 is always maintained at a higher temperature and is heated and lowered. As a result, the raw material stored in the steam source storage container 14 first starts to dissociate to generate steam. Therefore, dissociation of the raw material or the melt in the crucible 13 is suppressed.

Thus, for example, when a compound semiconductor composed of two elements is in a molten state, not only one component but also the other component becomes vapor (ZnSe et al., In many cases this corresponds). When the adjustment of the vapor pressure of some of the constituent elements is insufficient to suppress dissociation, the same raw material as the crystal growth raw material is stored in the vapor source storage container 14 as described above. The dissociation can be surely suppressed.

The present invention is not limited to the above-described embodiments. For example, a group II-VI such as CdTe other than ZnSe, a group III-V such as InP and GaP, or a ternary compound thereof. For example, it can be applied to the production of compound single crystals in which a part of the constituent elements dissociates and evaporates easily at a high temperature during crystal growth.

[0048]

As described above, according to the method for producing a compound single crystal of the present invention, even if the vapor of the high dissociation pressure component is heavier than the inert gas filled in the furnace body, The vapor atmosphere of the high dissociation pressure component generated in the vapor source storage container is immediately formed around the storage container. Moreover, since the vapor pressure is maintained at a predetermined pressure by the reservoir, it is possible to grow a good quality single crystal having the intended composition from the raw material melt in the raw material container.

Further, by disposing a seed crystal on the lower end side of the raw material storage container to perform crystal growth, it is possible to surely grow a single crystal having a predetermined orientation as a whole. Further, by storing the same raw material as the growing crystal raw material in the vapor source storage container and performing single crystal growth, dissociation of the raw material in the raw material storage container is further reliably suppressed, and as a result, the composition of the composition as intended is obtained. Single crystal growth can be performed.

In the apparatus for producing a compound single crystal of the present invention, since the airtight chamber provided with the communication passage is provided below, even if the vapor pressure due to dissociation during heating is high, the pressure difference between the inside and the outside of the airtight chamber is reduced. Since no force is exerted on the hermetic chamber, damage to the hermetic chamber is prevented. Moreover, a part of the steam flowing to the lower communication passage in the airtight chamber is deposited at the above-mentioned communication passage. As a result, the outflow of vapor to the outside of the airtight chamber is prevented, and thus the maintenance of the device for preventing the occurrence of, for example, a short-circuit accident is facilitated. Can be manufactured in a simple manner.

[Brief description of drawings]

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

FIG. 2 is a schematic vertical sectional view showing a configuration of a single crystal manufacturing apparatus according to another embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing the configuration of a conventional single crystal manufacturing apparatus.

[Explanation of symbols]

 1 Pressure Vessel (Furnace Body) 3 Main Heater (Main Heating Means) 4 Sub Heater (Sub Heating Means) 13 Crucible (Material Storage Container) 14 Vapor Source Storage Container 15 Airtight Chamber 16 Communication Passage 17 Reservoir 18 Seed Crystal 19 Vapor Source 20 High dissociation pressure component

Claims (4)

[Claims] 1. A raw material melted by heating and lowering a raw material storage container having an upper end opening containing a raw material for growing a single crystal in a heating region in which the temperature is increased as it goes upward in a furnace body filled with an inert gas. A method for producing a compound single crystal in which a single crystal is grown from a liquid, wherein a vapor source storage container for storing at least a high dissociation pressure component of raw material constituent elements is provided above the raw material storage container,
A reservoir for storing the high dissociation pressure component is provided below the raw material storage container, and at least a vapor of the high dissociation pressure component is generated from the vapor source storage container heated together with the raw material storage container in the heating region, and the raw material storage A method for producing a compound single crystal, which comprises performing single crystal growth while controlling the temperature of a reservoir independently of the heating temperature in the heating region in order to adjust the vapor pressure of the high dissociation pressure component around the container. 2. The method for producing a compound single crystal according to claim 1, wherein a single crystal is grown by disposing a seed crystal at the lower end of the raw material storage container. 3. The production of a compound single crystal according to claim 1, wherein a raw material having substantially the same composition as the raw material stored in the raw material storage container is stored in the vapor source storage container for single crystal growth. Method. 4. A hermetically sealed furnace body filled with an inert gas, a main heating means arranged in the furnace body to form a heating region having a higher temperature in the furnace body, and a raw material for growing a single crystal. And a raw material storage container having an upper end opening which is placed in the heating region and contains a high dissociation pressure component in the raw material constituent elements and is placed above the raw material storage container and heated in the heating region. A vapor source storage container, a reservoir that stores the high dissociation pressure component and is arranged below the raw material storage container, an auxiliary heating unit that heats the reservoir, a raw material storage container, a vapor source storage container, and a reservoir. An apparatus for producing a compound single crystal, which is provided with an airtight chamber made of an airtight material that is surrounded by the heating means and has a communication path that communicates the inside and the outside with each other below.