JPH08301696A - Production of compound semiconductor crystal and device therefor - Google Patents

Abstract

PURPOSE: To inexpensively obtain a high-purity and high-quality III-V group compound polycrystal by cooling a crucible after the amount of a group V raw material in a vapor pressure control part is decreased in a specific state by an amount to form a compound with a group III raw material in a crucible. CONSTITUTION: A vapor pressure in a sealed tube is gradually raised while heating a melt in a crucible so as not to raise the temperature at the wall of the sealed quartz tube too high more than a temperature for maintaining the vapor pressure of the group V raw material in the sealed tube at a fixed pressure. Then, synthetic reaction is promoted by making the vapor pressure in the sealed tube into a proper pressure higher than the equilibrium vapor pressure of a group V element in a compound. After the melt of the compound is formed, it is solidified from the lower end of the crucible at a proper rate to give the objective semiconductor polycrystal. Since the temperature at the wall of the sealed quartz tube can be reduced to a mush lower temperature than the softening point of crucible in the production method, Si contamination is extremely lessened and the sealed tube will not cause plastic deformation even if difference in pressure between the inside and outside of the sealed tube is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a compound semiconductor crystal and an apparatus therefor. More specifically, the present invention relates to a method for producing a high-purity and high-quality polycrystal, which is useful for the production of a compound semiconductor single crystal used for a substrate of a compound semiconductor device or the like, and an apparatus therefor. The present invention relates to a method for producing a single crystal using the polycrystal.

[0002]

2. Description of the Related Art III-V compound semiconductors are LEDs, L
It is used in D, other electronic devices, etc., and its progress has been remarkable in recent years. Substrate crystals used in these devices are GaAs, GaP, InP, etc.
Although it is a III-V group compound single crystal, normally, in the production of these single crystals, a melt having a compound composition is first generated and then solidified and grown as a single crystal. As a method of producing a melt having a compound composition, in the same apparatus as the apparatus for performing single crystal growth, the compound melt is produced from the raw materials of the compound constituent elements in the previous stage of the single crystal growth, and then the single crystal growth is directly performed. There is a direct synthesis method, and an indirect method in which a polycrystalline raw material previously synthesized by another device or process is melted to generate a compound melt and single crystal growth is performed. The main production methods of conventional bulk polycrystals used as raw materials for the latter single crystal growth method are summarized as follows: <1> Synthesis of Group III and V raw materials charged together in a container such as a crucible Method III and V are raw materials that are put together in a container such as a crucible and heated and melted to synthesize them. In order to control the loss due to evaporation of the raw materials of Group V, a closed lid for pressing the raw materials and B ₂ O ₃ etc. A method of sealing with the sealing liquid of and pressurizing with an inert gas from above,
There are a method of directly pressurizing the raw material with an inert gas, a method of locally repeating rapid heating-cooling of the raw material locally by high-frequency heating, and the like.

<2> V in the Group III raw material melt under the sealing liquid
Method for blowing Group III raw material gas The Group III melt in the crucible is sealed with a sealing liquid such as B ₂ O ₃ and pressurized with an inert gas, and the sealing liquid is passed from a container containing the Group V raw material through a blowing pipe. There are various compounds that are fed as a gas into the Group III melt below and have been devised, and the shape and function of the blowing tube have been devised, and the solidification method after compound melt synthesis is that of cooling in a crucible. There is also a method of directly shifting to single crystal growth.

<3> Method of reacting group V vapor in a sealed container with a group III raw material in a crucible or a boat A group III raw material is charged into a container such as a crucible or a boat and accommodated in a sealed container, In addition, the group V raw material is also contained in a container such as a crucible or in an appropriate place in this sealed container, and the temperature of the entire sealed container is raised to react with the group V vapor and the group III melt to form a compound melt. This is a method in which a compound polycrystal is prepared by cooling.

[0005]

However, in the conventional method <1> of synthesizing the III and V raw materials in the crucible by sealing with a sealing liquid or the like, the compound composition is stable because the sealing is incomplete. It is difficult to achieve this, and it is difficult to stabilize the thermal environment because it is performed in a high pressure atmosphere. Compared with this, in the method <2> in which the group V gas is blown into the melt in the crucible under the sealing liquid, the pressure vessel of the pressurizing vessel has a smaller pressure resistance, the composition can be easily controlled, and the single crystal can be produced by the same apparatus after the synthesis. Although it has the advantage that it can be transferred to growing, the device is too complicated from the viewpoint of compound polycrystal synthesis, and contamination from the encapsulant is also a problem.

In the method <3> of reacting group V vapor with a group III raw material in a container such as a crucible or a boat in a sealed container, strict composition control is possible in principle, and contamination by the sealing material is possible. However, there is a tendency that it is complicated even though the apparatus and process are basically relatively simple, and the original advantage of this method tends to be impaired. Hereinafter, those main problems will be further described.

First of all, quartz has been often used as a material for a hermetically sealed container for containing Group V vapor.
When synthesizing a compound such as As whose melting point exceeds the softening point of quartz, the temperature of the sealed container itself becomes unnecessarily high, for example, when the entire sealed container is put in an electric furnace. Even if the synthetic vapor pressure is not so high, the sealed container may be deformed or broken due to the pressure difference between the inside and outside of the sealed container. From this, there is an example in which the entire furnace is housed in a pressure vessel, and the deformation of the sealed vessel is measured to perform control so as to eliminate the pressure difference. There are also examples in which Si contamination from quartz is rejected and the material of the sealed container is changed to various ceramics or graphite. However, these materials also have low mechanical strength, and although the above-mentioned mechanism for eliminating the pressure difference between the inside and the outside is adopted, there is a drawback that the price of the ceramic-based material becomes high,
The pressure control system also complicates the device, for example, a part of the wall of the sealed container is made of metal foil to detect the differential pressure. Furthermore,
There is an example of observing a synthetic reaction by using a sealed container or a part thereof as a ceramic transparent to visible light or infrared light, but this also causes a cost increase.

By using the pressure control system as described above, the group V vapor pressure applied to the melt in the sealed container is controlled to be constant, or the group V vapor pressure of the vapor pressure control section in the sealed container is simply kept constant. Since the composition changes with the temperature of the melt and the V group vapor pressure also fluctuates as a result, the measured V group vapor is used for the purpose of preventing this and obtaining stability of the compound composition. There is also a method in which not only the temperature of the V group element reservoir but also the temperature of the growth compound is added to one of the control variables according to the pressure. Although these can be said to be useful as a method for growing a single crystal, there is a drawback that the apparatus and the process are too complicated for the purpose of producing a compound polycrystal. That is, the stoichiometric composition of the compound single crystal is determined by the vapor pressure control in the sense that the optimum vapor pressure that equilibrates with the compound having the exact stoichiometric composition is applied, not the equilibrium vapor pressure during single crystal growth. In this case, the raw material polycrystal in the case of a strictly stoichiometric composition has an excessive specification, and a stoichiometric composition without a second phase such as a group III rich phase. A composition extremely close to is sufficient. It is known that group III-V compounds exist not only in exactly one-to-one group III and group V atomic fractions but also in a small composition range, but the composition is very close to the stoichiometric composition. Means within this composition range.

Finally, when the Group V vapor pressure is applied to the Group III melt, the synthesis reaction rapidly progresses and the supply of the Group V vapor cannot follow it, so that the Group V vapor pressure drops rapidly. In order to prevent the sealed container from being deformed and destroyed, there is a method of adding an appropriate amount of the group III-V compound polycrystal to the group III melt in advance. However, from the viewpoint of not only cost reduction but also prevention of contamination of impurities, it is desirable to avoid such multi-step processes.

[0010]

In order to solve the above-mentioned problems, the present invention provides a raw material of a group III element having a small vapor pressure such as Al, Ga and In in a crucible or a crucible equipped with a susceptor. The raw material of the group V element having a large vapor pressure such as P, As, and Sb is put in a quartz sealed tube, and the vapor pressure control section in the sealed tube is separated from the crucible by an appropriate distance. It accommodates a combined amount of the amount necessary to generate the group raw material and the compound and the amount necessary to fill the internal volume of the sealed tube with the group V vapor of a predetermined pressure, and the end of the vapor pressure control unit is always a sealed tube. The temperature inside the crucible is raised to a predetermined temperature above the melting point of the compound at a predetermined rate of temperature increase while keeping the lowest temperature inside, and in parallel, the vapor pressure control unit also reduces the evaporation loss of at least the Group III raw material in the crucible. The vapor pressure of the group V element in the sealed tube is controlled by After raising the temperature to a predetermined temperature above the equilibrium vapor pressure and confirming that the amount of the group V raw material in the vapor pressure control unit has decreased to the amount that forms a compound with the group III raw material in the crucible, Provided is a method for producing a III-V group compound semiconductor polycrystal, characterized in that a compound melt in a crucible is solidified upward from the lower end by gradually cooling the crucible from the lower end.

The present invention is also a method for producing a mixed crystal semiconductor single crystal, wherein a certain amount of the surface layer of the mixed crystal polycrystal produced by the above method is removed, and then a single crystal is formed by a floating zone melting method. A method for producing a mixed crystal semiconductor single crystal is provided. Furthermore, the present invention comprises a heating furnace including a high-frequency heating unit and a radiant heating unit, a quartz sealed tube containing a raw material, a crucible, or a susceptor, and a vertical movement mechanism for the quartz sealed tube. Consists of a high-frequency coil and a heat-retaining tube made of quartz or the like, which is arranged inside the high-frequency coil if necessary depending on the heating temperature, and the radiant heating section is adjacent to at least one of the width direction of the high-frequency coil in the electric furnace. The quartz sealed tube consists of a crucible housing part and this crucible housing part, and a vapor pressure control part separated by an appropriate distance.The quartz sealed tube is surrounded by a crucible or a crucible. The susceptor mounted is housed with a proper gap between it and the quartz tube wall of the crucible housing part, and the vertical movement mechanism has a structure connected to this quartz tube, and the vapor pressure control part The lowest temperature While raising the temperature of the entire quartz sealed tube with the radiant heat from the radiant heating heater and the radiant heat from the crucible or the susceptor that generates heat by the high frequency heating, even if the raw material in the crucible exceeds the melting point of the compound, the quartz in the crucible storage part Make sure that the wall of the sealed tube does not become higher than or near the temperature required to maintain the vapor pressure in the sealed tube at the specified pressure, and lower the quartz sealed tube by the vertical movement mechanism to cool gradually from the lower end of the crucible. Also provided is a compound semiconductor crystal manufacturing apparatus characterized by causing the temperature of the vapor pressure control unit to follow a predetermined temperature.

[0012]

A feature of the present invention is that the temperature of the quartz sealed tube wall does not become much higher than the temperature required to maintain the group V vapor pressure in the sealed tube at a predetermined pressure, while the temperature of the melt in the crucible is raised. In parallel with this, gradually increase the vapor pressure in the sealed tube,
Promote the synthetic reaction by setting the vapor pressure in the sealed tube to an appropriate pressure higher than the equilibrium vapor pressure of the group V element in the compound,
After formation of the compound melt, solidification from the bottom of the crucible at an appropriate speed under an appropriate vapor pressure will result in high purity and high quality.
The III-V group compound polycrystal can be manufactured at low cost.

Since the temperature of the quartz envelope wall can be kept considerably lower than the softening point of quartz, Si contamination is very small, and the envelope wall is plastically deformed even if a pressure difference between the inside and outside of the envelope occurs. There is no. In addition, As, Sb system III-V
In the case of group compounds, the synthetic vapor pressure may be at most a few atmospheres, so even if the sealed tube is placed under atmospheric pressure, there is almost no possibility of mechanical destruction, so there is no need to put the entire furnace in an expensive pressure vessel, and by any chance. It only needs to be covered with a simple enclosure with an exhaust device in case the sealed tube breaks. However, P
In the case of a system, there is a risk of a pressure difference exceeding the mechanical strength of quartz, so it is necessary to put it in a pressure resistant container that can be balanced with this, but with a pressure resistance capacity of several tens to 100 atmospheres. No expensive high pressure vessels are required.

One of the advantages of raising the group V vapor pressure in parallel with the temperature rise of the melt is that the activity of the group III element in the melt is lowered, so that vacuum pumping is performed first. This is to prevent the group III raw material from escaping outside the crucible inside the quartz sealed tube. The other is that polycrystalline particles of the compound are gradually formed in the melt before the melt temperature reaches the melting point of the compound, which may cause a rapid change in vapor pressure due to a rapid synthesis reaction. Since it does not exist, it is possible to prevent the destruction of the sealed tube due to the drastic fluctuation of the pressure difference inside and outside the sealed tube.
The rate of increasing the vapor pressure is actually set to the rate of temperature rise of the vapor pressure control unit, but the vapor pressure is set to an equilibrium with the saturated solubility of the group V element at each melt temperature during temperature rise. The temperature rise is as a guide, but this need not be so strict.

If the group V vapor pressure in the sealed tube is made higher than the equilibrium vapor pressure in the compound, the synthetic reaction will proceed faster and the process will be more efficient. Therefore, the melting time will be shortened and the crucible and other equipment materials will be used. Less pollution. Further, in the method of the present invention, in order to accelerate the synthetic reaction and prevent the compound solid from being dispersed and fixed in various places in the crucible to form a porous polycrystal, the melt temperature is finally adjusted to Since the temperature is higher than the melting point by several tens of degrees Celsius or more, a higher applied vapor pressure is set in consideration of the increase in the equilibrium vapor pressure in the melt.

From the observation window provided in a part of the furnace, it can be confirmed that almost the compound melt is generated from the amount of the group V raw material remaining in the vapor pressure control section of the quartz sealed tube. The compound melt is cooled and solidified from the lower end of the crucible by gradually lowering the whole and pulling the crucible out of the high frequency coil to obtain a compound polycrystal. At this time, the group V vapor pressure in the sealed tube may be fixed to the same pressure as during synthesis, but the higher the pressure, the larger the amount of excess As in the melt. There is a possibility of danger, so be careful. The vapor pressure of the V group at the time of cooling can be selected to some extent, but it depends on the solidification rate and whether the composition of the polycrystalline body should be the III group rich side or the V group rich side. In any case, according to this method, if the cooling rate is appropriate, the melt composition of the melt in the upper part of the crucible is always adjusted by the reaction with the group V vapor atmosphere, and the stoichiometric composition from the lower end of the crucible becomes extremely high. It is possible to grow a III-V compound polycrystal having a similar composition.

Therefore, when it is desired to further shorten the time of the entire synthesis process, composition segregation within the intended polycrystal is performed, particularly in the case of a binary compound in which the raw materials of both group III and group V are one element. When there is no problem, even if the amount of residual Group V raw material in the vapor pressure control unit in the melt synthesis stage is increased to some extent, cooling is started and a polycrystalline body grows from the lower end of the crucible while the Group V element remains in the melt. Finally, a compound polycrystal having a very close stoichiometric composition can be finally obtained.
However, the third solidified second phase is likely to remain in the final solidifying portion, but if the falling rate of the sealed tube or the temperature of the crucible heating is slowed a little at the end, almost 100
A group III-V compound polycrystal can be obtained with a yield close to%.

The method described above can be applied not only to the binary compounds of the III-V group but also to the synthesis of multi-component mixed crystals or polycrystals of the II-VI group compounds. further,
By using this mixed crystal polycrystal, a mixed crystal single crystal can be easily grown by the FZ method (floating zone melting method).
In this case, single crystal crystallization is further facilitated by removing a certain thickness of the surface of the polycrystalline body by grinding or etching to make the mixed crystal ratio distribution in the radial direction of the polycrystalline body uniform.

The present invention will be specifically described with reference to the following examples.

[0020]

EXAMPLE 1 A GaAs polycrystal was synthesized by the method for producing a III-V compound semiconductor polycrystal of the present invention and an apparatus therefor. FIG. 1 is a sectional view of a GaAs manufacturing apparatus. Reference numeral (1) in the figure is a quartz sealed tube, which has a crucible fixing part (2) into which a crucible or a susceptor for heating a crucible is inserted, and an As vapor vent hole (3) under the crucible fixing part, and an As vapor pressure control at the lower end. Division (4)
P that was charged with the raw material As (5) and the raw material Ga (6)
The carbon susceptor (8) fitted with the BN crucible (7) was inserted into the crucible fixing part (2), vacuum exhaust was performed, and the upper end was sealed after baking.

The quartz sealed tube (1) is mounted in a heating furnace as shown in the figure. The heating furnace comprises an electric furnace (9) (10) (11) and a high frequency coil (12).
A quartz tube (13) for heat retention is arranged inside the (2).
From the susceptor (8), an appropriate gap is provided between the carbon susceptor (8) and the quartz sealing tube (1), and the quartz sealing wall of the crucible housing is not directly heated by the electric furnace. The temperature does not rise too much due to the radiation. On the contrary, a quartz tube (13) for heat retention is provided so that the temperature does not drop too much. The quartz sealed tube (1) is hung on the hook at the lower end of the support rod (15) connected to the vertical movement device (14) so that the crucible (7) is initially at an appropriate position in the high frequency coil (12). To do.

Further, the entire heating furnace is housed in a simple enclosure (16), and the exhaust device (17) prevents As from leaking out of the enclosure (16) even if the quartz sealed tube (1) is broken. I am trying. In the GaAs synthesizer having the above structure, the carbon susceptor (8) is induction-heated by the high-frequency coil (12) at a high frequency of an appropriate frequency to raise the raw material Ga (6) in the crucible (7). Start warming. At this time Ga (6)
If it is heated up to about 1240 ° C., which is the melting point of GaAs, most of the raw material Ga (6) evaporates and escapes to the outside of the crucible (7) and adheres to the inner wall of the quartz sealed tube (1). The electric furnaces (9) (10) (1) so that the vapor pressure control unit (4) becomes the lowest temperature part and As is not attached to the inner wall of the quartz sealed tube (1) other than the As vapor pressure control unit (4).
1) is heated to raise the As vapor pressure in the sealed tube.

Next, through the observation window (21), the susceptor (8) near the crucible (7) to be measured by the pyroscope.
The temperature of the soaking part with an appropriate width of up to 1280 ° C, and the temperature of the vapor pressure control part (4) indicated by the thermocouple (18) are set to 65 ° C.
When the temperature is raised from room temperature to 0 ° C in about 30 minutes, 50% or more of the charged raw material As is absorbed in the melt in the crucible (7),
In order to absorb the predetermined amount of As required for the formation of the compound melt, it is sufficient to hold it for about 30 minutes, and the observation window (19)
It is confirmed by visually observing the decrease amount of As in the vapor pressure control unit through (20).

Next, the vertical movement device (14) is operated to move and lower the quartz sealed tube (1). The moving speed at this time needs to be adjusted to some extent mainly by the diameter of the crucible (7). Taking an example of the case where the inner diameter of the crucible (7) is 20 mm, the average temperature of the steam pressure control unit (4) is 1.5 mm / mm while controlling the temperature of the electric furnace (11) so as to be fixed at 650 ° C.
By moving at a speed of about 100 minutes for about 100 minutes, a dense GaAs polycrystal having a Ga-rich second phase and a length of about 150 mm could be obtained. It takes about 3 hours from the start of heating up to turning off the power of the whole equipment, diameter 20mm, length 150mm
That is, the GaAs polycrystal was obtained.

When the impurity density was measured by SIMS, Si was 1 × 10 ¹⁵ cm ^-3 or less and S was 4 × 10 5.
It was found to be a high-purity GaAs polycrystal with ¹⁴ cm ^-3 or less and Cr of 1 × 10 ¹⁴ cm ^-3 or less. If the inner diameter of the PBN crucible is slightly tapered, a good quality polycrystalline ingot without the second phase can be produced, and the crucible (7) can be inverted and tapped to remove the ingot easily. The crucible (7) has almost no visible damage. Most crucibles remain clean without damage even after being used 50 times or more. Also, the quartz sealed tube (1) can be repeatedly used except for the upper end portion which is welded during vacuum sealing. Example 2 Using the same apparatus as in Example 1, Ga and Al were charged in the crucible (7) at a molar ratio of 7: 3, and As was charged in the vapor pressure control section (4). With a crucible temperature of 1400 ° C. and a vapor pressure control unit temperature of 670 ° C., an average speed of 0.7 mm / min was used to cool the crucible from the lower end to obtain a Ga having a diameter of 20 mm and a length of 70 mm.
_{A 1-X} AlxAs polycrystal could be obtained. The composition x distribution in the axial direction of this type of polycrystal has a gradient portion with a width of 10 to 15 mm at both ends, and the composition x is constant during that time. Example 3 A GaAs polycrystal was synthesized by directly heating a melt in a crucible at high frequency without using a carbon susceptor. In this case, the same crucible (7) as in Example 1 is used, and the high-frequency heating coil (12) and the quartz heat insulating tube (13) arranged inside thereof are used.
The diameter of the crucible fixing part (2) is made smaller by reducing the diameter of the susceptor (8) and the quartz sealing tube (1) is also smaller.
Alumina-based ceramics were used for the.

[0026]

As described above in detail, according to the present invention, a high purity and high quality III crystal having a very close stoichiometric composition can be obtained by an extremely simple structure, an inexpensive apparatus and a simple process.
A group V compound polycrystal can be produced in high yield. Therefore, the production cost and the quality of the III-V compound single crystal can be reduced. In particular, the method of the present invention
It is an optimal method for producing a compound polycrystal to be used as a raw material for growing a single crystal by the Z method, the VB method, the VGF method, or the like.

The present invention can also be applied to the synthesis of II-VI group compounds and other compounds having a component with a high vapor pressure as a constituent element. When the vapor pressure of the constituent elements exceeds 10 atm near the melting point, such as in P-based compounds, the enclosure as described in Example 1 is replaced with an equilibrium vapor pressure near the melting point of the compound. A pressure vessel having pressure resistance may be used.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a preferred embodiment of the present invention.

[Explanation of symbols]

 1 Quartz Sealed Tube 2 Crucible Fixing Section 3 As Steam Vent 4 Steam Pressure Control Section 5 Raw Material As 6 Raw Material Ga 7 PBN Crucible 8 Carbon Susceptor 9 Electric Furnace 10 Electric Furnace 11 Electric Furnace 12 High Frequency Heating Coil 13 Heat Keeping Quartz Tube 14 Upper and Lower Moving device 15 Support rod 16 Enclosure 17 Exhaust device 18 Thermocouple 19 Observation window 20 Observation window 21 Observation window

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yutaka Sawafuji 7-20-1, Nagamachi, Taichiro-ku, Sendai City, Miyagi Prefecture Tohoku Special Steel Co., Ltd.

Claims (3)

[Claims] 1. A raw material of a group III element having a low vapor pressure is charged into a crucible or a crucible equipped with a susceptor and accommodated in a quartz sealed tube, while a raw material of a group V element having a high vapor pressure is charged. , The vapor pressure control unit in the sealed tube, which is separated from the crucible by an appropriate distance, is required to fill the amount of the group III raw material and the compound required to generate the compound and the volume in the sealed tube with the group V vapor of a predetermined pressure. The combined amount is stored, and the end of the vapor pressure control unit always raises the temperature of the raw material in the crucible to a predetermined temperature above the melting point of the compound while keeping the lowest temperature in the sealed tube, and in parallel, Then, the vapor pressure control unit also controls the vapor pressure of the group V element in the sealed tube to be equal to or higher than the equilibrium vapor pressure of the compound melt at a predetermined temperature increasing rate at which evaporation loss of the group III raw material in the crucible is suppressed. The amount of the group V raw material in the vapor pressure control unit that forms a compound with the group III raw material in the crucible After confirming that the crucible has decreased, the compound melt in the crucible is solidified upward from the lower end by gradually cooling the crucible from the lower end under an appropriate Group V vapor pressure. III -Method for producing Group V compound semiconductor polycrystal. 2. A method for producing a mixed crystal semiconductor single crystal, comprising:
A method for producing a mixed crystal semiconductor single crystal, which comprises removing a certain amount of a surface layer of a mixed crystal polycrystal produced by the method of claim 1 and then performing single crystallization by a floating zone melting method. 3. A heating furnace comprising a high-frequency heating unit and a radiant heating unit, a quartz sealed tube containing a raw material, a crucible or a susceptor, and a mechanism for vertically moving the quartz sealed tube. , Consisting of a high-frequency coil and a heat insulating tube arranged inside the high-frequency coil as needed depending on the heating temperature, and the radiant heating section is composed of a radiant heater adjacent to at least one of the high-frequency coil in the axial direction, The quartz sealed tube is composed of a crucible housing part and a vapor pressure control part separated from the crucible housing part by an appropriate distance. The quartz sealed tube is a crucible or a crucible with a susceptor installed around the crucible housing part. It is housed with an appropriate gap between it and the wall of the quartz sealed tube, and the vertical movement mechanism has a structure connected to this quartz sealed tube. When the temperature of the entire quartz sealed tube is increased by the heat generated by the raw material, the crucible, or the radiant heat from the susceptor, even if the raw material in the crucible exceeds the melting point of the compound, the quartz sealed wall of the crucible housing part is sealed. When the quartz sealed tube is lowered by the vertical movement mechanism in order to gradually cool from the lower end of the crucible, the temperature should not be higher than or near the temperature necessary to maintain the vapor pressure of
An apparatus for producing a compound semiconductor crystal, characterized in that the temperature of a vapor pressure controller is made to follow a predetermined temperature.