JP4399631B2 - Method for manufacturing compound semiconductor single crystal and apparatus for manufacturing the same - Google Patents

Description

The present invention relates to a method of manufacturing a compound semiconductor single crystal such as a GaAs single crystal mainly by a vertical board method such as a VB method or a VGF method, and more particularly to a method and apparatus for manufacturing a compound semiconductor single crystal containing carbon. It is.

  As a method for producing a compound semiconductor single crystal, for example, an LEC method (liquid sealing pulling method), a VB method (vertical Bridgman method), a VGF method (vertical temperature gradient method), and the like are known.

  The LEC method is a method in which a compound semiconductor raw material is melted in a crucible, and then the crystal is grown by gradually pulling up the crystal while covering the entire top surface of the melt with boron oxide which is a liquid sealing agent. .

  The VGF method / VB method (hereinafter referred to as a vertical boat method) is a method in which a compound semiconductor raw material is melted in a crucible, and the melt is melted in a vertical furnace having a temperature distribution with a high upper portion and a lower lower portion. This is a method of growing crystals sequentially from the lower end of the crucible by lowering the temperature of the entire temperature distribution or lowering the crucible relatively.

  FIG. 5 shows the configuration of an apparatus for manufacturing a semiconductor single crystal such as a GaAs single crystal by the vertical board method. In the figure, 1 is an airtight container, 2 is a heater provided therein, 3 is a crucible made of pyrolytic boron nitride (hereinafter referred to as PBN), and 4 is a holding cylinder for accommodating and holding the crucible 3. The crucible 3 has a raw material container 3a and a seed crystal container (nozzle part) 3b at the bottom thereof, and the upper surface is open.

  When manufacturing a semiconductor single crystal, the seed crystal 10 is accommodated in the seed crystal accommodating part 3b of the crucible 3, and the solid compound semiconductor raw material 11 is accommodated in the raw material accommodating part 3a. The sealing agent 12 is arrange | positioned. Thereafter, the temperature of the inside of the crucible 3 is increased by the heater 2 disposed so as to surround the outer periphery of the crucible 3 so that the compound semiconductor raw material 11 and the sealant 12 are melted, The upper part of the crystal 10 is melted and this state is maintained for a predetermined time. Thereafter, the temperature in the crucible 3 is gradually lowered from the seed crystal side, and a crystal is grown from the interface between the seed crystal 10 and the melt of the raw material 11 while reproducing the crystal orientation of the seed crystal 10, thereby producing a semiconductor single crystal. obtain.

When growing a single crystal with a crucible 3 made of PBN, it is common to use boron oxide (B ₂ 0 ₃ ) as the sealant 12. The reason for using B ₂ 0 ₃ as a sealant, by the B ₂ 0 ₃ was dissolved softens at high temperature to cover the surface of the raw material melt and the seed crystal, an element constituting the compound melt and the seed crystal It is because it can suppress dissociation from. In addition, the B ₂ 0 ₃ enters between the raw material melt and seed crystal and the PBN crucible, thereby preventing direct contact between the raw material melt and seed crystal and the PBN crucible and generating polycrystals. The effect of suppressing the phenomenon can also be expected.

  By the way, when a compound semiconductor single crystal is manufactured by growing a single crystal from a raw material melt by the LEC method, the vertical boat method or the like, carbon or the like is usually mixed as a residual impurity in the obtained single crystal. These impurities are considered to be generated from graphite usually used for heaters and other furnace members and mixed into the raw material melt in the crucible through the atmospheric gas.

  As described above, the residual impurities mixed in the compound semiconductor single crystal usually show a concentration change along the growth direction of the obtained single crystal, and in particular, impurities that affect the electrical characteristics of the compound semiconductor single crystal. The change in concentration may cause various inconveniences in the device stage.

On the other hand, in the LEC method using a stainless steel chamber as an airtight container, it is known that there is a correlation between the CO gas concentration in the chamber and the carbon concentration in the GaAs crystal in a high-pressure Ar or N ₂ gas atmosphere. For example, Patent Document 1 shows that there is a strong correlation between the CO gas concentration in the LEC furnace and the carbon concentration in the GaAs crystal.

In the LEC method, the carbon concentration in the GaAs crystal can be controlled by controlling the CO gas concentration in the chamber using such correlation. Therefore, for example, in Patent Document 1, as an example based on the LEC method, a raw material container containing a raw material melt is placed in a predetermined gas atmosphere, and among the H ₂ , O ₂ , CO _2, and CO in the atmospheric gas, A technique for detecting a concentration of at least one component gas and controlling the detected component concentration to a predetermined value so that residual impurities mixed in the obtained single crystal are maintained at a predetermined concentration throughout the ingot. It is disclosed.

  For example, Patent Document 2 discloses that a compound semiconductor material is produced by sealing a carbon oxide gas having a predetermined partial pressure and a compound semiconductor material in a gas impermeable hermetic container (quartz ampoule) and increasing the temperature of the hermetic container. After melting, the temperature of the hermetic container is lowered to solidify the melted compound semiconductor raw material, and the compound semiconductor crystal is grown, so that carbon can be added to the compound semiconductor crystal with extremely high reproducibility. It is disclosed.

Japanese Patent Laid-Open No. 1-209089 JP 11-335195 A Advanced Electronics Series I-4 Bulk Crystal Growth Technology (Takeshi Hikawa Henfukan) p184 Fig. 7.22

However, the prior art described in Patent Document 1 is a technique for controlling the carbon concentration in the crystal by controlling the atmospheric gas concentration in the LEC method, and the effect is sufficient even when applied to the vertical boat method as it is. It can be easily inferred that it cannot be obtained. That is, in the vertical boat method, on the contact area between the atmospheric gas and the crucible melt is small, the crystal as the LEC method is responsible for reaction promotion, such stirring the melt of B ₂ 0 ₃ and raw materials There is no means. Therefore, it is difficult to control a sufficient carbon concentration even if only the atmospheric gas concentration is controlled.

In addition, the conventional technique described in Patent Document 2 performs crystal growth in a state in which a compound semiconductor raw material and a carbon oxide gas having a predetermined partial pressure are sealed in a gas impermeable hermetic container (quartz ampule). Therefore, there is a problem that the means for adjusting the carbon concentration is scarce.

In view of the above circumstances, the present invention provides a compound semiconductor crystal manufacturing method and apparatus for manufacturing a compound semiconductor single crystal having a uniform carbon concentration by simply adding simple equipment to conventional equipment. The purpose is to provide.

The method for producing a compound semiconductor single crystal of the first invention is a method for producing a compound semiconductor single crystal by a vertical boat method,
Storing the compound semiconductor raw material and the sealant raw material in an airtight container;
Heating and melting the compound semiconductor raw material and the encapsulant raw material,
Adjusting the inside of the airtight container to a carbon oxide gas atmosphere of a predetermined concentration;
A step of stirring the sealing compound and / or the molten compound semiconductor raw material by an appropriate stirring means to dissolve carbon in the carbon oxide gas atmosphere into the molten compound semiconductor raw material;
A step of producing a compound semiconductor single crystal by cooling and solidifying the melted sealant while stirring .

A method for producing a compound semiconductor single crystal of the second invention is a method for producing a compound semiconductor single crystal by a vertical boat method,
Storing the compound semiconductor raw material and the sealant raw material in an airtight container;
Heating and melting the compound semiconductor raw material and the encapsulant raw material,
In the sealant and / or in the molten compound semiconductor raw material, an appropriate carbon member is immersed, and the carbon in the carbon member is dissolved in the molten compound semiconductor raw material;
A step of producing a compound semiconductor single crystal by cooling and solidifying the melted sealant while stirring .

A method for producing a compound semiconductor single crystal according to a third invention is the method for producing a compound semiconductor single crystal according to the second invention ,
The sealing agent and / or the melted compound semiconductor raw material is stirred by the carbon member.

A method for producing a compound semiconductor single crystal of a fourth invention is a method for producing a compound semiconductor single crystal by a vertical boat method,
Storing the compound semiconductor raw material and the sealant raw material in an airtight container;
Heating and melting the compound semiconductor raw material and the encapsulant raw material,
Adjusting the inside of the airtight container to a carbon oxide gas atmosphere of a predetermined concentration;
In the sealing agent and / or in the molten compound semiconductor raw material, an appropriate carbon stirring means is immersed and stirred, and the carbon in the carbon oxide gas atmosphere and the carbon in the carbon member are removed. Dissolving in the molten compound semiconductor raw material;
A step of producing a compound semiconductor single crystal by cooling and solidifying the melted sealant while stirring .

The method for producing a compound semiconductor single crystal according to a fifth invention is characterized in that, in any one of the first to fourth inventions , boron oxide is used as the sealing agent.

According to a sixth aspect of the present invention , there is provided the method for producing a compound semiconductor single crystal according to the fifth aspect , wherein the weight of the boron oxide is 1 to 10% of the weight of the compound semiconductor raw material.

In the method for producing a compound semiconductor single crystal according to a seventh aspect of the present invention , in any one of the first aspect and the fourth to sixth aspects, the carbon oxide gas contains at least one gas of CO gas or CO ₂ gas. It is characterized by that.

According to an eighth aspect of the present invention , there is provided the method for producing a compound semiconductor single crystal according to any one of the first to seventh aspects, wherein the compound semiconductor material contains GaAs.

An apparatus for producing a compound semiconductor single crystal according to a ninth aspect of the invention is an apparatus for producing a compound semiconductor single crystal used in the method for producing a compound semiconductor single crystal according to any one of the first to eighth aspects,
An airtight container capable of maintaining a carbon oxide gas atmosphere of a predetermined concentration, a crucible placed in the airtight container and containing at least a compound semiconductor raw material, and the raw material in the crucible placed in the airtight container is heated and melted and the crucible And a compound semiconductor single crystal that grows a compound semiconductor single crystal by gradually cooling and solidifying from a melt lower part of the heated and melted compound semiconductor raw material In the manufacturing equipment of
In the airtight container, a carbon member that can be immersed in a melt of the compound semiconductor raw material or a sealant that seals the upper part of the raw material melt is disposed, and the vertical position of the carbon member is arranged. And an elevating mechanism capable of moving the head.

An apparatus for producing a compound semiconductor single crystal according to a tenth aspect of the invention is characterized in that, in the ninth aspect, a mechanism for further rotating the carbon member is provided.

An apparatus for producing a compound semiconductor single crystal according to an eleventh aspect of the invention is the ninth or tenth aspect of the invention, in which the carbon member is placed in the melt of the compound semiconductor raw material or the sealing by controlling the operation of the elevating mechanism. Control means for adjusting the position and time for immersion in the agent is provided.

  According to the present invention, carbon in the carbon oxide in the atmosphere is used as a carbon supply source to the raw material melt using a member disposed in the hermetic container, and / or a member disposed in the hermetic container is made of carbon. By using the member as a carbon supply source to the raw material melt, it is possible to add some equipment to the conventional equipment and / or to make the part of the equipment made of carbon without requiring particularly complicated equipment. By doing so, a compound semiconductor single crystal having a uniform carbon concentration can be produced.

FIG. 1 is a cross-sectional view showing a compound semiconductor single crystal manufacturing apparatus according to an embodiment of the present invention.
This manufacturing apparatus is for manufacturing a semiconductor single crystal such as a GaAs single crystal by a vertical boat method, and there is a method described below.
(A) Sealing agent (B ₂ O ₃ ) 12 or sealing agent (B ₂ ) in addition to carbon supply by controlling the concentration of carbon oxide (CO gas or the like) in the hermetic container 1 according to the prior art A system having a stirring plate 20 for stirring O ₃ ) 12 and the compound semiconductor raw material melt 11.
(B) A method in which the stirring plate 20 is a carbon member as a carbon supply source that replaces the carbon oxide in the hermetic container 1 according to the prior art.
(C) A method in which (a) and (b) described above are used in combination.

First, the method (a) will be described.
The manufacturing apparatus used in the method (a) includes an airtight container 1 that can be evacuated and filled with atmospheric gas from the outside, a crucible 3 made of pyrolytic boron nitride (PBN) disposed in the center of the airtight container 1, and a crucible. A holding cylinder 4 that accommodates and holds 3, a mechanism 5 that raises and lowers and / or rotates the holding cylinder 4 (only a lifting / rotating rod is shown), and a heater 2 that is provided in the airtight container 1 so as to surround the holding cylinder 4, And a stirring plate 20 provided above the crucible 3, and a mechanism 22 (only the lifting / rotating rod is shown) for moving the stirring plate 20 up and down.

  The crucible 3 has a raw material storage part 3a for storing a compound semiconductor raw material and a seed crystal storage part (nozzle part) 3b at the bottom, and the upper end is open. The heater 2 heats and melts the raw material in the crucible 3 and can generate a temperature distribution in the vertical direction with respect to the crucible 3. The manufacturing apparatus also includes control means (not shown) for controlling the heater 2, the crucible lifting / lowering mechanism 5, the carbon plate lifting / lowering mechanism 22, and the like. This control means adjusts the position and time when the stirring plate 20 is immersed in the raw material melt or sealant in the crucible 3 by controlling the operation of the carbon plate lifting and rotating mechanism 22. Can do. As the material of the stirring plate 20, a material that has little influence on the compound semiconductor raw material 11, such as BN, is used.

Next, a method for manufacturing a semiconductor single crystal will be described.
In the case of producing a single crystal, first, the seed crystal 10 is accommodated in the seed crystal accommodating portion 3b of the crucible 3, and the solid compound semiconductor raw material (raw material containing GaAs) 11 is accommodated in the raw material accommodating portion 3a. A sealing agent 12 is disposed on the top of the compound semiconductor raw material 11. Boron oxide (B ₂ O ₃ ) is used as the sealant 12, and the weight of boron oxide is 1 to 10% of the weight of the compound semiconductor raw material 11. The sealant 12 is for covering the entire upper surface of the raw material melt when growing a single crystal.

Next, the temperature of the inside of the crucible 3 is raised by the heater 2 disposed so as to surround the outer periphery of the crucible 3 in the hermetic container 1, thereby melting the compound semiconductor raw material 11 and the sealing agent 12, and the seed crystal 10. Thaw the top of the.
While maintaining this state for a predetermined time, the atmosphere is replaced with gas to adjust the atmosphere to a carbon oxide gas having a predetermined concentration (including at least one of CO gas and CO ₂ gas). Next, the temperature in the crucible 3 is gradually lowered from the seed crystal side to start growing a single crystal. Here, the raising / lowering / rotating mechanism 22 of the stirring plate 20 is controlled to lower the stirring plate 20 into the sealant 12 and / or the compound semiconductor raw material 11, and stirring is performed at 1 to 20 rpm, preferably 4 to 10 rpm. Needless to say, the concentration of the carbon oxide gas in the atmospheric gas may be adjusted during single crystal growth.

  Here, when the stirring plate 20 is lowered, the sealing plate 12 is stirred, the compound semiconductor raw material 11 is stirred, the sealing agent 12 and the compound by adjusting the height direction size and the lowering position of the stirring plate 20 itself. A configuration of stirring in the semiconductor raw material 11 can be selected. In any case, the effect of the present invention can be obtained, but from the viewpoint that it is preferable not to give extra disturbance to the growing compound semiconductor single crystal, the configuration of stirring the sealing agent 12 Is preferred.

  By this stirring, the compound semiconductor single crystal is grown by cooling and solidifying the compound semiconductor raw material 11 while supplying carbon from the carbon oxide gas in the atmosphere to the melt of the compound semiconductor raw material 11. The stirring may be performed continuously, but it is also preferable to stop the operation appropriately while observing the carbon distribution in the compound semiconductor single crystal that is cooled and solidified.

Next, the method (b) will be described.
The manufacturing apparatus used for the method (b) is almost the same as the manufacturing apparatus used for the method (a) described above, but a carbon member is used instead of the stirring plate 20. Various members can be used as the carbon member regardless of the shape, such as a plate shape or a rod shape. In the mechanism 22 for raising and lowering and rotating, the rotation mechanism is not an essential requirement, but may be provided as desired.

Next, a method for manufacturing a semiconductor single crystal will be described.
The manufacturing method used for the method (b) is almost the same as the manufacturing method used for the method (a) described above. However, a seed crystal 10, a solid compound semiconductor raw material (raw material containing GaAs) 11 and a sealing agent 12 are disposed in the crucible 3, and the compound semiconductor raw material 11 and the sealing agent 12 are melted by the heater 2, and the seed crystal While the upper part of 10 is melted and this state is maintained for a predetermined time, the atmosphere is replaced with a gas to adjust the carbon oxide gas atmosphere to a predetermined concentration. Of course, in a carbon oxide gas atmosphere of a predetermined concentration or less, carbon can be supplied into the compound semiconductor raw material 11 melt from the above-described carbon member without any special adjustment.

  Here, when the carbon member is lowered and the position is determined, the carbon member is immersed in the sealant 12, or in the compound semiconductor raw material 11, or in the sealant 12 and the compound semiconductor raw material 11. It is possible to select a configuration of whether or not to immerse. In any case, the effect according to the present invention can be obtained, but from the viewpoint that the concentration distribution of carbon in the compound semiconductor raw material 11 is preferably not so steep, it is contained in the sealant 12. The structure to immerse is preferable. Further, the configuration of whether or not the carbon member is rotated can be selected. However, it may be determined as appropriate, including the temporary stoppage of rotation, while observing the carbon distribution in the compound semiconductor single crystal that is cooled and solidified. When the carbon member is rotated, the member becomes the carbon stirring means. Thus, the compound semiconductor single crystal is grown by cooling and solidifying the melted compound semiconductor raw material 11.

Further, the method (c) will be described.
The manufacturing apparatus used for the method (c) has a configuration that combines the manufacturing apparatuses used for the methods (a) and (b) described above, and uses a carbon member in place of the stirring plate 20.

Next, a method for manufacturing a semiconductor single crystal will be described.
The manufacturing method used for the method (c) has a configuration that combines the manufacturing methods used for the methods (a) and (b) described above. That is, a seed crystal 10, a solid compound semiconductor raw material (raw material containing GaAs) 11 and a sealant 12 are disposed in the crucible 3, and the compound semiconductor raw material 11 and the sealant 12 are melted by the heater 2, and the seed crystal When the atmosphere is replaced with the gas while the upper part of 10 is melted and this state is maintained for a predetermined time, the carbon oxide gas atmosphere is adjusted to a predetermined concentration, and the carbon is obtained from the above-described carbon oxide gas atmosphere and the carbon member. The compound semiconductor raw material 11 is supplied into the melt. At this time, the lowered position of the carbon member and the presence or absence of rotation may be determined in the same manner as in the above-described method (b). Thus, the compound semiconductor single crystal is grown by cooling and solidifying the melted compound semiconductor raw material 11.

A semiconductor single crystal having a uniform carbon concentration in the range of 0.1 to 20 × 10 ¹⁵ cm ⁻³ by manufacturing the semiconductor single crystal by the methods (a) to (c) described above, the tail from the crystal shoulder A semiconductor single crystal having a resistivity distribution within ± 13% to the shoulder is obtained. From these single crystals, wafers having a desired range of carbon concentration and a desired range of resistivity are manufactured with high productivity.
In addition, since the apparatus used for this production is the one that adds the stirring plate 20 and its up-and-down / rotation mechanism 22 to a conventional facility or prepares a carbon member, special and expensive equipment is added. There is no need, the equipment cost can be reduced, and the operation is simple.

  Next, examples and comparative examples of single crystal production will be described. Here, first, a comparative example will be described first, and then an example will be described.

(Comparative Example 1)
It is an example of the vertical boat method which concerns on a prior art.
In Comparative Example 1, first, a cylindrical crucible made of pyrolytic boron nitride (PBN) with an inner diameter of 80 mm, a raw material (GaAs) of 6 kg, a GaAs seed crystal of orientation <100>, and B ₂ as a sealing agent are used. 285 g of O ₃ is put and set at a predetermined position in the airtight container.

Next, the inside of the hermetic container was evacuated and replaced with Ar gas as an atmospheric gas, and then pressurized to a predetermined pressure, and heated with a vertical heater to dissolve the upper portion of the raw material crystal and the seed crystal. At this time, the sealing agent B ₂ O ₃ is dissolved on the raw material melt to prevent As from scattering from the raw material melt.

  With this raw material dissolved, the CO gas concentration in the atmospheric gas was adjusted to a constant value. After this adjustment was completed, the heater temperature was lowered from the seed crystal side, and the entire raw material melt was solidified to grow crystals. During crystal growth, adjustment was continued so that the CO gas concentration was always constant.

  After the growth was completed, the temperature was lowered to room temperature, and then the crystal was taken out from the crucible. In the obtained crystal, the length of the straight cylinder having a diameter of 80 mm was about 190 mm. At the position of the crystal shoulder (solidification rate g = 0.1) and straight body tail (solidification rate g = 0.9), a 4 mm thick FT-IR (Fourier Transform Infrared Spectroscopy) sample was cut out. went. The remaining crystal was subjected to predetermined annealing, and then a sample for resistivity measurement having a thickness of 1 mm was cut out.

When the carbon concentration substituted with arsenic sites was measured by the FT-IR method, it was 2.0 × 10 ¹⁵ cm ⁻³ at the crystal shoulder and 4.0 × 10 ¹⁴ cm ⁻³ at the crystal tail. Similarly, FIG. 2 shows the results of crystal growth by changing the CO concentration in the atmosphere and measuring the carbon concentration. FIG. 2 is a graph in which the horizontal axis represents the CO concentration in the atmosphere, and the vertical axis represents the carbon concentration. The measurement result of the crystal shoulder is plotted with ◆, and the measurement result of the crystal tail is plotted with Δ. As shown in FIG. 2, a good correlation was found between the CO gas concentration in the furnace at the crystal shoulder and the carbon concentration in the crystal, but no correlation was found in the crystal tail.

  Further, FIG. 3 shows the result of examining the relationship between the resistivity and the carbon concentration using the crystal after annealing. In FIG. 3, the horizontal axis represents the carbon concentration and the vertical axis represents the resistivity, and the measurement results are plotted. As shown in FIG. 3, there was a good correlation between resistivity and carbon concentration. From these results, even if the CO gas concentration in the hermetic container is controlled, the effect is up to the position of the shoulder portion of the crystal. It has been found that conventional control of the CO gas concentration in the furnace alone is not sufficient.

(Comparative Example 2)
This is an extension of the prior art.
In Comparative Example 2, the procedure is almost the same as in Comparative Example 1, but the CO gas concentration in the growing hermetic vessel is increased with respect to the initial concentration, and when the crystal growth reaches the crystal tail portion, it is twice the concentration at this point. Growth was carried out while adjusting to 4 times or 10 times. However, almost the same result as in FIG. 2 was obtained.

Example 1
In this example, as shown in FIG. 1, a BN stirring plate 20 was provided, and the growth was performed while the stirring plate 20 was immersed in B ₂ O ₃ as the sealing agent 12 and rotated during crystal growth. At this time, the CO gas concentration in the hermetic container is increased to 4 times the concentration at the time when the growth of the gas gas in the hermetic container is increased from the initial concentration and the crystal growth reaches the crystal tail. Growing while adjusting.

  FIG. 4 shows the result of examining the resistivity distribution in the growth direction of the crystal thus grown. FIG. 4 shows the crystal position from the shoulder of the crystal grown on the horizontal axis, the resistivity on the vertical axis, the value of the comparative example (before improvement) plotted with ■, and connected with a broken line. This is a graph in which the value after improvement is plotted with ◆ and connected with a solid line. As shown in FIG. 4, in the case of this example (after improvement) as compared with the comparative example (before improvement), it has a uniform resistivity with less variation from the crystal shoulder portion to the entire crystal of the tail portion. all right. That is, it was confirmed that a uniform carbon concentration could be achieved throughout the crystal.

(Example 2)
In this example, as shown in FIG. 1, a carbon stirring plate 20 was provided, and growth was performed by immersing the stirring plate 20 in B ₂ O ₃ as the sealant 12 during crystal growth. At this time, the CO gas concentration in the airtight container was set to a constant value.

The stirring plate 20 can be immersed in the sealant 12 at an arbitrary position and for an arbitrary time, and can further rotate. By soaking the stirring plate 20 in this manner, carbon can be supplied into the raw material melt. Further, it is possible to promote the supply of carbon from the CO gas by stirring the B ₂ O ₃ or GaAs melt using the stirring plate 20.

  When the distribution of resistivity in the growth direction of the crystal thus grown was examined, as shown in FIG. 4, in the case of this example (after improvement), the crystal shoulder as compared with the comparative example (before improvement). It was found that there was a uniform resistivity with little variation over the entire crystal from the head to the tail. In other words, it was confirmed that a uniform carbon concentration could be achieved over the entire crystal related to the wafer manufacturing part.

It is a longitudinal cross-sectional view of the manufacturing apparatus of the compound semiconductor single crystal which concerns on embodiment of this invention. It is a figure which shows the relationship between the CO gas density | concentration in the airtight container (inside a furnace) and the carbon density | concentration in a GaAs crystal concerning the comparative example (conventional method and its extension technique). It is a figure which shows the relationship between the carbon density | concentration in the crystal which concerns on a comparative example (conventional method and its extension technique), and resistivity. It is the characteristic comparison figure of the Example (after improvement) of this invention, and a comparative example (before improvement), and is the figure which showed distribution of the resistivity of the growth direction in a crystal | crystallization. It is a longitudinal cross-sectional view of the manufacturing apparatus of the conventional compound semiconductor single crystal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Heater 3 Crucible 3a Raw material accommodating part 3b Seed crystal accommodating part 5 Elevating and rotating mechanism of crucible 10 Seed crystal 11 Compound semiconductor raw material 12 Sealant (B ₂ O ₃ )

Claims (11)

A method for producing a compound semiconductor single crystal by a vertical boat method,
Storing the compound semiconductor raw material and the sealant raw material in an airtight container;
Heating and melting the compound semiconductor raw material and the encapsulant raw material,
Adjusting the inside of the airtight container to a carbon oxide gas atmosphere of a predetermined concentration;
A step of stirring the sealing compound and / or the molten compound semiconductor raw material by an appropriate stirring means to dissolve carbon in the carbon oxide gas atmosphere into the molten compound semiconductor raw material;
A method of producing a compound semiconductor single crystal by cooling and solidifying the melted sealant while stirring . A method for producing a compound semiconductor single crystal by a vertical boat method,
Storing the compound semiconductor raw material and the sealant raw material in an airtight container;
Heating and melting the compound semiconductor raw material and the encapsulant raw material,
In the sealant and / or in the molten compound semiconductor raw material, an appropriate carbon member is immersed, and the carbon in the carbon member is dissolved in the molten compound semiconductor raw material;
A method of producing a compound semiconductor single crystal by cooling and solidifying the melted sealant while stirring . A method for producing a compound semiconductor single crystal according to claim 2,
A method for producing a compound semiconductor single crystal, wherein the sealing agent and / or the melted compound semiconductor raw material is stirred by the carbon member. A method for producing a compound semiconductor single crystal by a vertical boat method,
Storing the compound semiconductor raw material and the sealant raw material in an airtight container;
Heating and melting the compound semiconductor raw material and the encapsulant raw material,
Adjusting the inside of the airtight container to a carbon oxide gas atmosphere of a predetermined concentration;
In the sealing agent and / or in the molten compound semiconductor raw material, an appropriate carbon stirring means is immersed and stirred, and the carbon in the carbon oxide gas atmosphere and the carbon in the carbon member are removed. Dissolving in the molten compound semiconductor raw material;
A method of producing a compound semiconductor single crystal by cooling and solidifying the melted sealant while stirring .   The method for producing a compound semiconductor single crystal according to claim 1, wherein boron oxide is used as the sealant.   6. The method for producing a compound semiconductor single crystal according to claim 5, wherein the weight of the boron oxide is 1 to 10% of the weight of the compound semiconductor raw material. The method for producing a compound semiconductor single crystal according to claim 1, wherein the carbon oxide gas contains at least one of a CO gas and a CO ₂ gas.   The method for producing a compound semiconductor single crystal according to claim 1, wherein the compound semiconductor raw material contains GaAs. A manufacturing apparatus for a compound semiconductor single crystal used in the method for manufacturing a compound semiconductor single crystal according to claim 1,
An airtight container capable of maintaining a carbon oxide gas atmosphere of a predetermined concentration, a crucible placed in the airtight container and containing at least a compound semiconductor raw material, and the raw material in the crucible placed in the airtight container is heated and melted and the crucible And a compound semiconductor single crystal that grows a compound semiconductor single crystal by gradually cooling and solidifying from a melt lower part of the heated and melted compound semiconductor raw material In the manufacturing equipment of
In the airtight container, a carbon member that can be immersed in the melt of the compound semiconductor raw material or a sealant that seals the upper portion of the raw material melt is disposed, and the vertical position of the carbon member is arranged. An apparatus for manufacturing a compound semiconductor single crystal, characterized in that an elevating mechanism capable of moving is provided. The apparatus for producing a compound semiconductor single crystal according to claim 9, further comprising a mechanism for rotating the carbon member. Control means for adjusting the position and time when the carbon member is immersed in the melt of the compound semiconductor raw material or in the sealant by controlling the operation of the lifting mechanism is provided. The manufacturing apparatus of the compound semiconductor single crystal of Claim 9 or 10 .

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