JP5516635B2 - Group III nitride crystal production equipment - Google Patents

Description

The present invention relates to a production equipment of I II-nitride crystal.

  At present, InGaAlN-based (group III nitride) devices used as purple-blue-green light sources are mainly MO-CVD (metal organic chemical vapor deposition) or MBE on sapphire substrates or SiC substrates. It is manufactured by crystal growth using a method (molecular beam crystal growth method) or the like. As a problem when sapphire or SiC is used as a substrate, there is an increase in crystal defects due to a large difference in thermal expansion coefficient and lattice constant between the substrate and the group III nitride. For this reason, the device characteristics are poor, which leads to the disadvantage that it is difficult to further elongate the life of the light emitting device, for example, or the operating power is increased.

  Furthermore, in the case of a sapphire substrate, since it has an insulating property, it is impossible to take out an electrode from the substrate side like a conventional light emitting device, and an electrode is taken out from the surface side of a crystal-grown nitride semiconductor. Is required. As a result, there is a problem that the device area becomes large, leading to high costs. Further, the group III nitride semiconductor device fabricated on the sapphire substrate is difficult to separate the chip by cleavage, and it is not easy to obtain the resonator end face required for the laser diode (LD) by cleavage. For this reason, at present, the resonator end face is formed by dry etching, or after the sapphire substrate is polished to a thickness of 100 μm or less, the resonator end face is formed in a form close to cleavage. Also in this case, it is difficult to easily perform the resonator end face and the chip separation as in a conventional LD in a single process, resulting in a complicated process and an increase in cost.

  In order to solve these problems, a GaN substrate is desired, and a method of forming a thick film on a GaAs substrate or a sapphire substrate by using the HVPE method (hydride vapor phase epitaxial growth method) and removing these substrates later. Are proposed in Patent Document 1 and Patent Document 2.

Although GaN free-standing substrates can be obtained by these methods, basically different types of materials such as GaAs and sapphire are used as the substrate for formation, so the difference in thermal expansion coefficient and lattice between the group III nitride and the substrate material. Due to the constant difference, high-density crystal defects remain. Even if this defect density can be reduced, it is 105 to 106 cm ⁻² . In order to realize a high performance (high output, long life) semiconductor device, it is necessary to further reduce the defect density. Further, in order to manufacture a single group III nitride crystal substrate, one GaAs substrate or sapphire substrate as the underlying substrate is required, and it is necessary to remove it. Therefore, a thick film having a thickness of several hundreds μm must be grown by vapor phase growth, the process is complicated, and an extra base substrate is required, resulting in an increase in manufacturing cost.

On the other hand, the method disclosed in Patent Document 3 uses sodium azide (NaN ₃ ) and metal Ga as raw materials in a stainless steel reaction vessel (inner dimensions; inner diameter = 7.5 mm, length = 100 mm). A GaN crystal is grown by sealing in a nitrogen atmosphere and holding the reaction vessel at a temperature of 600 to 800 ° C. for 24 to 100 hours. In the case of this Patent Document 3, crystal growth is possible at a relatively low temperature of 600 to 800 ° C., and the pressure in the vessel is relatively low at about 100 kg / cm ² at most, which is a practical growth condition. It is a feature. However, the problem with this method is that the size of the crystals obtained is small enough to be less than 1 mm.

  Until now, the present inventors have made intensive efforts to realize a high-quality group III nitride crystal by reacting a mixed melt composed of an alkali metal and a group III metal with a group V raw material containing nitrogen. Have been doing. The invention relating to this is disclosed in Patent Documents 4 to 36. This method is called the flux method.

  The feature of this flux method is that it is possible to grow extremely high-quality group III nitride crystals. Up to now, the invention has led to an increase in crystal size and further improvement in quality by improving and improving the growth method and growth apparatus of this high-quality group III nitride crystal. Current technical issues include further crystal size expansion.

  As an obstacle to the increase in crystal size, there is flux evaporation. Alkali metal is mainly used as the flux. When the alkali metal evaporates from the mixed melt containing the group III metal and the alkali metal, the quantity ratio of the flux to the group III metal changes. This leads to variations in crystal quality and inhibition of crystal size expansion.

  The present inventors have improved the evaporation of the flux in Patent Document 9, Patent Document 18, and Patent Document 26. Patent Document 9 discloses that the alkali metal is confined in the reaction vessel by controlling the temperature above the surface of the mixed melt or by devising the introduction direction of the nitrogen source gas. Patent Document 18 discloses suppression of alkali metal evaporation by controlling the gas pressure in the reaction vessel and devising the shape of the lid of the mixed melt holding vessel. Patent Document 26 discloses replenishing the reduced alkali metal by introducing the alkali metal from the outside.

  By these inventions, fluctuations in the quantity ratio between the flux and the group III metal can be suppressed, and as a result, stable crystal growth is realized, leading to reduction in variation in crystal quality and increase in crystal size.

  However, in the conventional flux method, it is difficult to prevent the alkali metal from evaporating from the mixed melt to the outside.

Inventions of this is to prevent evaporation of the flux from the molten mixture is to provide an apparatus for manufacturing a Group III nitride crystal can be manufactured group III nitride crystal.

Moreover, according to this invention, a manufacturing apparatus is provided with a reaction container, a holding | maintenance container, a heating means, piping, and a heating means . The reaction vessel can be sealed. The holding container is accommodated in the reaction container and holds a melt containing a group III metal and a flux. The heating means is disposed outside the reaction vessel and heats the reaction vessel. Piping, with connecting the source of material containing nitrogen on the outside of the reaction vessel and the reaction vessel, and has a possible holding structure the flux in a liquid state inside. The heating means maintains the flux held in the pipe in a liquid state. The liquid flux held in the pipe moves in the pipe in a direction corresponding to the pressure difference between the pressure in the space in the reaction vessel and the pressure in the space on the supply source side from the flux in the pipe. The piping is in a closed state or a state in which the closed state is released by the movement of the flux in the piping.

The gas-liquid interface on the supply side of the flux in the liquid state held in the pipe is maintained in the pipe when there is no pressure difference .

Preferably, the manufacturing apparatus further includes another heating unit. The other heating means includes a temperature of the gas-liquid interface closest to the holding container among the at least two gas-liquid interfaces of the liquid state flux held in the pipe in the melt held in the holding container. Set the temperature to prevent the flux from decreasing.

Preferably, the reaction vessel has a structure capable of holding a liquid flux inside. The liquid flux is held in the pipe and the reaction vessel.

Preferably, the manufacturing apparatus further includes a temperature gradient applying unit. The temperature gradient applying unit applies a temperature gradient to the pipe so as to suppress substantial evaporation of the liquid state flux held in the pipe.

Preferably, the substance containing nitrogen is a gas. And the interface which the flux of the liquid state hold | maintained in piping is in contact with the gas from a supply source in this piping is smaller than the internal diameter of piping.

Preferably, the manufacturing apparatus further includes a float. The float is disposed in the pipe, has a specific gravity smaller than that of the flux in the liquid state, and defines the size of the interface.

Preferably, the manufacturing apparatus further includes an auxiliary pipe and a second heating unit . The auxiliary pipe connects the reaction vessel with a gas supply source other than nitrogen outside the reaction vessel. The second heating means maintains the flux held in the auxiliary pipe in a liquid state. The flux in the liquid state held in the auxiliary pipe is in a direction corresponding to the pressure difference between the pressure in the space in the reaction vessel and the pressure in the space on the supply source side of the gas other than nitrogen in the auxiliary pipe. Move through the auxiliary piping. The auxiliary pipe has a structure capable of holding a flux in a liquid state inside , and is in a closed state or a state in which the closed state is released by movement of the flux in the auxiliary pipe. .

Preferably, the manufacturing apparatus further includes a temperature gradient applying unit. The temperature gradient applying means applies a temperature gradient to the auxiliary pipe so as to suppress substantial evaporation of the liquid state flux held in the auxiliary pipe.

  Preferably, the gas other than nitrogen is an inert gas.

Preferably, the liquid flux is an alkali metal.

According to this invention, it can be produced III-nitride crystal to prevent the evaporation of the flux to the outside from the melt. As a result, a large group III nitride crystal can be produced at a lower cost and higher quality than conventional ones.

FIG. 1 is a diagram for explaining a schematic configuration of a GaN crystal manufacturing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a view (No. 1) for explaining a manufacturing method by the manufacturing apparatus of FIG. FIG. 3 is a diagram (No. 2) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 4 is a view (No. 3) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 5 is a view (No. 4) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 6 is a diagram showing the relationship between the nitrogen gas pressure and the crystal growth temperature when a GaN crystal is grown. FIG. 7 is a diagram for explaining a schematic configuration of a GaN crystal manufacturing apparatus according to Embodiment 2 of the present invention. FIG. 8 is a view (No. 1) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 9 is a diagram (No. 2) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 10 is a diagram for explaining a schematic configuration of a GaN crystal manufacturing apparatus according to Embodiment 3 of the present invention. FIG. 11 is a view (No. 1) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 12 is a diagram (No. 2) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 13 is a diagram (No. 3) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 14 is a diagram for explaining a schematic configuration of a GaN crystal manufacturing apparatus according to Embodiment 4 of the present invention. FIG. 15 is a view (No. 1) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 16 is a diagram (No. 2) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 17 is a diagram for explaining a schematic configuration of a GaN crystal manufacturing apparatus according to Embodiment 5 of the present invention. FIG. 18 is a diagram (No. 1) for describing a manufacturing method by the manufacturing apparatus of FIG. FIG. 19 is a diagram (No. 2) for explaining the manufacturing method by the manufacturing apparatus 17. FIG. 20 is a diagram (No. 3) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 21 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the sixth embodiment. FIG. 22 is a timing chart of the temperatures of the melt holding container, the reaction container, and the gas supply pipe. FIG. 23 is a schematic diagram showing state changes in the melt holding container and the reaction container at timing t1 and timing t2 shown in FIG. FIG. 24 is a diagram (No. 1) for describing a manufacturing method by the manufacturing apparatus of FIG. FIG. 25 is a diagram (No. 2) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 26 is a diagram (No. 3) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 27 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the seventh embodiment. FIG. 28 is a diagram (No. 1) for describing a manufacturing method by the manufacturing apparatus of FIG. FIG. 29 is a diagram (No. 2) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 30 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the eighth embodiment. FIG. 31 is a view (No. 1) for describing a manufacturing method by the manufacturing apparatus of FIG. FIG. 32 is a diagram (No. 2) for explaining the manufacturing method by the manufacturing apparatus of FIG. 30. FIG. 33 is a diagram (No. 3) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 34 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the ninth embodiment. FIG. 35 is a view (No. 1) for describing a production method by the production apparatus of FIG. FIG. 36 is a (second) diagram for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 37 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the tenth embodiment. FIG. 38 is a diagram (No. 1) for describing a manufacturing method by the manufacturing apparatus of FIG. FIG. 39 is a diagram (No. 2) for explaining the manufacturing method by the manufacturing apparatus of FIG. FIG. 40 is a diagram (No. 3) for explaining the manufacturing method by the manufacturing apparatus of FIG.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
Next, Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic configuration of a GaN crystal manufacturing apparatus 100A as a group III nitride crystal manufacturing apparatus according to the first embodiment of the present invention. Here, nitrogen gas (N ₂ gas) is used as the substance containing nitrogen.

  A manufacturing apparatus 100A shown in FIG. 1 includes a reaction vessel 103, a melt holding vessel 101, heaters 109, 110, and 111, a nitrogen gas supply source (nitrogen gas cylinder) 105, gas supply pipes 104, 117, and 119, and a valve 115. , 118, 120, pressure sensor 108, gas exhaust pipe 114, vacuum pump 116, pressure regulator 106, and the like.

  The reaction vessel 103 is a closed vessel made of stainless steel. In the reaction vessel 103, a melt holding vessel 101 is accommodated. When the melt holding container 101 is accommodated in the reaction container 103, a predetermined gap is formed between the lower part of the melt holding container 101 and the bottom surface inside the reaction container 103. It has become.

  As an example, the melt holding container 101 is made of P-BN (pioritic boron nitride) and can be taken out from the reaction container 103. In the melt holding container 101, a mixed melt 102 containing sodium (Na) as a flux and metal gallium (Ga) as a group III metal is put.

  The heater 109 is disposed adjacent to the outside of the reaction vessel 103 and heats the reaction vessel 103 from the side.

  The heater 110 is disposed adjacent to the outside of the reaction vessel 103 and heats the reaction vessel 103 from the bottom surface. That is, the reaction vessel 103 is heated by the heater 109 and the heater 110. The melt holding container 101 is heated through the reaction container 103.

  The pressure sensor 108 is provided in the upper part of the reaction vessel 103 and is used to monitor the pressure of the gas in the reaction vessel 103.

  The gas discharge pipe 114 is a pipe for discharging the gas in the reaction vessel 103. One end of the gas discharge pipe 114 is connected to the vacuum pump 116, and the other end is connected to an opening provided in the upper part of the reaction vessel 103.

  The valve 115 is provided in the middle of the gas discharge pipe 114 and close to the reaction vessel 103. When the vacuum pump 116 is in operation and the valve 115 is open, the gas in the reaction vessel 103 is discharged.

  The gas supply pipes 104, 117, and 119 are pipes for supplying nitrogen gas into the reaction vessel 103. One end of the gas supply pipe 119 is connected to the nitrogen gas cylinder 105. The other end of the gas supply pipe 119 is branched into two, and one end of the gas supply pipe 104 and one end of the gas supply pipe 117 are connected to each other.

  The other end of the gas supply pipe 117 is connected to an opening provided at the top of the reaction vessel 103.

  The other end of the gas supply pipe 104 is connected to an opening provided at the bottom of the reaction vessel 103.

  The valve 118 is provided in the middle of the gas supply pipe 117 and close to the reaction vessel 103. Nitrogen gas is supplied into the reaction vessel 103 when the valve 118 is open, and supply of nitrogen gas into the reaction vessel 103 is shut off when the valve 118 is closed.

  The gas supply pipe 104 is a pipe having a U-shaped part. The heater 111 has a plurality of heating portions, is disposed adjacent to the rising portion and the bottom portion of the gas supply pipe 104 that are far from the reaction vessel 103, and is held by the U-shaped portion of the gas supply pipe 104. A temperature gradient that suppresses substantial evaporation of molten Na (liquid) is applied to the U-shaped portion.

  The valve 120 is provided in the middle of the gas supply pipe 104 and close to the reaction vessel 103.

  The pressure regulator 106 is provided in the middle of the gas supply pipe 119 and is used to adjust the pressure of nitrogen gas supplied into the reaction vessel 103.

  Further, as shown in FIG. 2, the reaction vessel 103 can be separated from each pipe including each valve, and can be operated by moving the reaction vessel 103 into a glove box (not shown). It is.

  Next, a method for manufacturing a GaN crystal using the manufacturing apparatus 100A configured as described above will be described.

(1) Close each valve.
(2) The reaction vessel 103 is separated from each pipe and placed in a glove box having an argon (Ar) atmosphere.
(3) Open the lid of the reaction vessel 103 and take out the melt holding vessel 101 from the reaction vessel 103. Then, the raw material Ga and the flux Na are placed in the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(4) Molten Na (referred to as 112) is placed in the reaction vessel 103.
(5) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103. Thereby, as shown in FIG. 3 as an example, the gap between the reaction vessel 103 and the melt holding vessel 101 is filled with molten Na112. Note that the reaction of oxygen and moisture with Ga and Na can be prevented by handling Ga and Na in an argon atmosphere.
(6) Close the lid of the reaction vessel 103. It should be noted that the space other than that occupied by the mixed melt 102 inside the melt holding vessel 101 is connected to the space inside the reaction vessel 103 and has almost the same atmosphere and pressure. Hereinafter, these two spaces are collectively referred to as a space portion 107 in the reaction vessel 103. Here, the space portion 107 in the reaction vessel 103 is an argon atmosphere.
(7) Take out the reaction vessel 103 from the glove box and connect it to each pipe. At this time, for example, nitrogen gas is flowed so that no air remains in each gas supply pipe. As a result, each gas supply pipe is filled with nitrogen gas.
(8) The vacuum pump 116 is operated.
(9) The valve 115 is opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 is discharged. That is, the gas purge in the reaction vessel 103 is performed. (10) With reference to the pressure sensor 108, when the pressure in the space 107 in the reaction vessel 103 reaches a predetermined pressure, the valve 115 is closed.
(11) Open the valve 118 and supply nitrogen gas into the reaction vessel 103. At this time, referring to the pressure sensor 108, the pressure regulator 106 is adjusted so that the pressure of the nitrogen gas in the reaction vessel 103 is approximately 15 atm. When the pressure in the reaction vessel 103 reaches 15 atmospheres, the valve 118 is closed. Each of the above steps is a temperature at which molten Na between the melt holding vessel 101 and the reaction vessel 103 maintains a liquid state, and a temperature at which substantial vapor of Na is suppressed (for example, 100 ° C.). Done in
(12) The valve 120 is opened. Accordingly, as shown in FIG. 4 as an example, a part of the molten Na 112 that fills the gap between the reaction vessel 103 and the melt holding vessel 101 fills the U-shaped portion of the gas supply pipe 104. At this time, the molten Na 112 has two of a gas-liquid interface A in the reaction vessel 103 and a gas-liquid interface B in the gas supply pipe 104. Here, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 113 of the gas supply pipe 104 are substantially equal to each other, the level L1 of the gas-liquid interface A and the level L2 of the gas-liquid interface B are substantially equal to each other. I'm doing it.
(13) The temperature in the reaction vessel 103 is raised to 800 ° C. by the heaters 109 and 110. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

At this time, the heater 111 is controlled so that Na maintains a liquid state at the gas-liquid interface B and substantial evaporation of Na is suppressed. Here, “substantial evaporation is suppressed” means that even if Na diffuses from the gas-liquid interface B into the space 113 on the nitrogen cylinder side of the gas supply pipe 104, the diffusion amount is the time during crystal growth. Within (several tens to hundreds of hours), it means that the crystal growth is not adversely affected. For example, if the heater 111 is controlled so that the temperature of the gas-liquid interface B is maintained at 150 ° C., the liquid state is maintained because it is naturally higher than the melting point of Na (98 ° C.), and the vapor pressure is 7.6 × 10 ⁻ It becomes ⁹ atmospheres, and there is almost no decrease of molten Na112 within the time during crystal growth. At 300 ° C. and 400 ° C., the Na vapor pressures are 1.8 × 10 ⁻⁵ and 4.7 × 10 ⁻⁴ atm, respectively.

  Therefore, the temperature of the gas-liquid interface A becomes higher than the temperature of the gas-liquid interface B, and a temperature gradient is generated between the gas-liquid interface A and the gas-liquid interface B.

In the temperature raising process of the reaction vessel 103, the pressure regulator 106 adjusts the pressure so that the pressure in the space 107 in the reaction vessel 103 and the pressure in the space 113 on the nitrogen cylinder side of the gas supply pipe 104 are substantially the same. While controlling, the pressure is increased to 40 atm.
(14) The temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure in the space 107 in the reaction vessel 103 decreases, as shown in FIG. 5 as an example, the molten Na 112 reacts due to the differential pressure between the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103. Move into the container 103. As a result, the gas-liquid interface A rises and the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104. At this time, the nitrogen gas becomes a bubble and rises in the molten Na 112 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 of the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. In this way, nitrogen gas is supplied from the nitrogen gas cylinder 105 to the space 107 of the reaction vessel 103 until the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other. When the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are approximately equal to each other, the level of the gas-liquid interface A and the level of the gas-liquid interface B are approximately equal to each other. In the process of crystal growth, the state shown in FIG. 4 and the state shown in FIG. 5 are repeated, and nitrogen gas is supplied to the space 107 in the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is 800 ° C. which is the same as the temperature in the reaction vessel 103. Since the Na vapor pressure at this temperature is as large as about 0.45 atm, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, as described above, the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate. Therefore, the Na vapor pressure is small, and Na is upstream from the gas-liquid interface B (nitrogen cylinder 105 side). It is negligible to spread to. Note that even if the molten Na 112 in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. Since it adheres to the temperature-controlled region and is liquefied there, it does not affect the introduction of nitrogen gas into the space 107 in the reaction vessel 103.

  And the GaN crystal manufactured by the method mentioned above is higher quality than the GaN crystal manufactured by the conventional flux method, and has a big size.

  FIG. 6 is a diagram showing the relationship between the nitrogen gas pressure and the crystal growth temperature when a GaN crystal is grown. In FIG. 6, the horizontal axis represents the crystal growth temperature, and the vertical axis represents the nitrogen gas pressure. Note that T on the horizontal axis in FIG. 6 represents an absolute temperature.

  Referring to FIG. 6, region REG1 is a region where the GaN crystal is dissolved, and region REG2 is a region where the GaN crystal is crystal-grown from the seed crystal by suppressing nucleation in mixed melt 102. REG3 is a region where many nuclei are generated on the bottom surface and side surfaces in contact with the mixed melt 102, and columnar GaN crystals grown in the c-axis (<0001>) direction are manufactured.

  In the manufacturing apparatus 100A, while preventing evaporation of metal Na from the mixed melt 102 to the outside by the molten Na 112, various kinds of gases are generated using the nitrogen gas pressure and the crystal growth temperature in the regions REG1, REG2, and REG3 shown in FIG. A GaN crystal is manufactured.

  For example, seed crystal growth and spontaneous nucleus growth are performed using the nitrogen gas pressure and the crystal growth temperature in the regions REG2 and REG3, respectively.

  Also, many spontaneous nuclei are generated in the melt holding vessel 101 using the nitrogen gas pressure and crystal growth temperature in the region REG3, and then many spontaneous nuclei are generated using the nitrogen gas pressure and crystal growth temperature in the region REG1. A part of the GaN crystal is melted, and then a GaN crystal is grown using the remaining spontaneous nuclei as a seed crystal using the nitrogen gas pressure and the crystal growth temperature in the region REG2.

  Furthermore, many spontaneous nuclei are generated in the melt holding vessel 101 using the nitrogen gas pressure and the crystal growth temperature in the region REG3, and then the spontaneous nuclei are seeded using the nitrogen gas pressure and the crystal growth temperature in the region REG2. A GaN crystal is grown.

  As described above, in the manufacturing apparatus 100A, various GaN crystals are manufactured while preventing the metal Na from evaporating from the mixed melt 102 to the outside by the molten Na112.

  As described above, according to the first embodiment, when the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by the molten Na 112, Nitrogen gas is introduced into the reaction vessel 103 when the nitrogen pressure in the reaction vessel 103 decreases. As a result, it becomes possible to achieve both the prevention of diffusion of Na to the outside of the reaction vessel 103 and the stable supply of the nitrogen raw material, and the stable growth of the GaN crystal is continued, and the low-cost, high-quality, large-size, and homogeneous GaN. Crystals can be produced. Therefore, it is possible to grow a large group III nitride crystal with higher quality than the conventional flux method.

  Further, since Na same as the flux exists outside the melt holding container 101 and Na vapor is generated from the gas-liquid interface A, the evaporation of Na from the mixed melt 102 in the melt holding container 101 is suppressed. It becomes possible to do. As a result, the amount (ratio) of Na in the mixed melt 102 is stabilized, and stable growth of the GaN crystal can be maintained at a low cost.

  In the first embodiment, the case where the opening connected to the other end of the gas discharge pipe 114 is provided in the upper part of the reaction vessel 103 has been described. However, the present invention is not limited to this. In short, it is sufficient that the gas in the reaction vessel 103 can be discharged when the space between the reaction vessel 103 and the melt holding vessel 101 is filled with molten Na.

  In the first embodiment, the case where the opening connected to the other end of the gas supply pipe 117 is provided in the upper part of the reaction vessel 103 has been described. However, the present invention is not limited to this. In short, it is only necessary that nitrogen gas can be introduced into the reaction vessel 103 when the space between the reaction vessel 103 and the melt holding vessel 101 is filled with molten Na.

  In the first embodiment, the case where the opening connected to the other end of the gas supply pipe 104 is provided in the lower part of the reaction vessel 103 has been described. However, the present invention is not limited to this. In short, when the pressure in the reaction vessel 103 becomes lower than the pressure suitable for growing GaN crystals in the melt holding vessel 101, the molten Na moves into the reaction vessel 103 due to the pressure difference, and the gas supply pipe When the closed state of 104 is released and the pressure in the reaction vessel 103 becomes a pressure suitable for growing GaN crystals in the melt holding vessel 101, a part of the molten Na in the reaction vessel 103 is transferred to the gas supply pipe. It is only necessary that the gas supply pipe 104 can be closed by moving into the inside 104.

[Embodiment 2]
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 7 shows a schematic configuration of a GaN crystal manufacturing apparatus 100B as a group III nitride crystal manufacturing apparatus according to Embodiment 2 of the present invention. In the following description, the same reference numerals are used for the same or equivalent components as those in the first embodiment, and the description thereof is simplified or omitted.

  7 includes a reaction vessel 103, a pressure vessel 301, a melt holding vessel 101, heaters 109, 110, and 111, a nitrogen gas supply source (nitrogen gas cylinder) 105, and gas supply pipes 104, 117, and 119. 303, valves 115, 118, 120, 305, 307, two pressure sensors 108, 304, gas exhaust pipes 114, 306, vacuum pump 116, pressure regulator 106, and the like. That is, the manufacturing apparatus 100B is obtained by adding the pressure vessel 301, the pressure sensor 304, the gas supply pipe 303, the valves 305 and 307, and the gas discharge pipe 306 to the manufacturing apparatus 100A in the first embodiment.

  The pressure vessel 301 is a stainless steel sealable vessel. In the pressure vessel 301, the reaction vessel 103, heaters 109, 110, and the like are accommodated.

  The gas supply pipe 303 is a branch of the gas supply pipe 117 and is provided to supply nitrogen gas into the pressure vessel 301. One end of the gas supply pipe 303 is connected in the middle of the gas supply pipe 117, and the other end is connected to the opening of the pressure vessel 301.

  The pressure sensor 304 is provided on the top of the pressure vessel 301 and is used to monitor the pressure in the pressure vessel 301.

  The valve 305 is attached to the gas supply pipe 303 in the vicinity of the pressure vessel 301. The valve 305 supplies the nitrogen gas into the pressure vessel 301 or stops supplying nitrogen gas into the pressure vessel 301.

  The gas exhaust pipe 306 has one end connected to the pressure vessel 301 and the other end connected to the gas exhaust pipe 114. The gas discharge pipe 306 guides the gas in the pressure vessel 301 to the vacuum pump 116.

  The valve 307 is attached to the gas discharge pipe 306 in the vicinity of the pressure vessel 301. The valve 307 guides the gas in the pressure vessel 301 to the vacuum pump 116 or stops the supply of the gas in the pressure vessel 301 to the vacuum pump 116 side.

Next, a method for manufacturing a GaN crystal using the manufacturing apparatus 100B configured as described above will be described.
(1) Close each valve.
(2) The reaction vessel 103 is disconnected from each pipe, and the reaction vessel 103 is taken out from the pressure vessel 301.
(3) The taken-out reaction vessel 103 is placed in a glove box with an argon atmosphere.
(4) The melt holding container 101 is taken out from the reaction vessel 103, and raw material Ga and flux Na are put into the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(5) Put molten Na into the reaction vessel 103.
(6) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103. Thereby, as shown in FIG. 3 as an example, the gap between the reaction vessel 103 and the melt holding vessel 101 is filled with molten Na.
(7) Close the lid of the reaction vessel 103.
(8) Take out the reaction vessel 103 from the glove box and store it in a predetermined position in the pressure vessel 301.
(9) The reaction vessel 103 and each pipe are connected. At this time, for example, nitrogen gas is flowed so that no air remains in each gas supply pipe. As a result, each gas supply pipe is filled with nitrogen gas.
(10) Close the lid of the pressure vessel 301.
(11) The vacuum pump 116 is operated.
(12) The valves 115 and 307 are opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 and the gas existing in the space portion 302 between the pressure vessel 301 and the reaction vessel 103 are discharged.
(13) Referring to the pressure sensors 108 and 304, when the pressure of the space portion 107 in the reaction vessel 103 and the space portion 302 between the pressure vessel 301 and the reaction vessel 103 reach a predetermined pressure, the valves 115 and 307 are turned on. Closed.
(14) The valves 118 and 305 are opened, and nitrogen gas is supplied into the reaction vessel 103 and the pressure vessel 301. At this time, referring to the pressure sensors 108 and 304, the pressure regulator 106 is controlled so that the pressure of the nitrogen gas in the reaction vessel 103 and the pressure vessel 301 is approximately 15 atm. When the pressure in the reaction vessel 103 and the pressure vessel 301 reaches 15 atmospheres, the valve 305 is kept open and the valve 118 is closed. The above steps are performed at a temperature at which molten Na between the melt holding vessel 101 and the reaction vessel 103 maintains a liquid state, and at a temperature at which substantial evaporation of Na is suppressed (for example, 100 ° C.). .
(15) The valve 120 is opened. Thereby, as shown in FIG. 8 as an example, a part of the molten Na filling the gap between the reaction vessel 103 and the melt holding vessel 101 fills the U-shaped portion of the gas supply pipe 104. Here, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 113 of the gas supply pipe 104 are substantially equal to each other, the level of the gas-liquid interface A and the level of the gas-liquid interface B substantially coincide with each other. Yes.
(16) Heat the melt holding container 101 and the reaction container 103 to 800 ° C. by the heaters 109 and 110. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

  At this time, the heater 111 is controlled so that Na maintains a liquid state at the gas-liquid interface B and substantial evaporation of Na is suppressed. Therefore, the temperature of the gas-liquid interface A becomes higher than the temperature of the gas-liquid interface B, and a temperature gradient is generated between the gas-liquid interface A and the gas-liquid interface B.

In the temperature raising process of the reaction vessel 103, the pressure in the space 107 in the reaction vessel 103, the pressure in the space 113 on the nitrogen cylinder side of the gas supply pipe 104, and the pressure in the space 302 in the pressure vessel 301 are substantially the same. Thus, the pressure is increased to 40 atm while pressure is controlled by the pressure regulator 106.
(17) The temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure of the space 107 in the reaction vessel 103 decreases, as shown in FIG. 9 as an example, the molten Na 112 reacts due to the differential pressure between the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103. Move into the container 103. As a result, the gas-liquid interface A rises and the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104. At this time, the nitrogen gas becomes a bubble and rises in the molten Na 112 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 of the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. In this way, nitrogen gas is supplied from the nitrogen gas cylinder 105 to the space 107 of the reaction vessel 103 until the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other. When the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are approximately equal to each other, the level of the gas-liquid interface A and the level of the gas-liquid interface B are approximately equal to each other. In the process of crystal growth, the state shown in FIG. 8 and the state shown in FIG. 9 are repeated, and nitrogen gas is supplied to the space 107 in the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is 800 ° C. which is the same as the temperature in the reaction vessel 103. Since the Na vapor pressure at this temperature is as large as about 0.45 atm, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, as described above, the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate. Therefore, the Na vapor pressure is small, and Na is upstream from the gas-liquid interface B (nitrogen cylinder 105 side). It is negligible to spread to. Even if the molten Na in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. It adheres to the temperature-controlled region, becomes molten Na, and does not affect the introduction of nitrogen into the space 107 in the reaction vessel 103.

  In the manufacturing apparatus 100B, the GaN crystal is manufactured using the nitrogen gas pressure and the crystal growth temperature included in the regions REG1, REG2, and REG3 shown in FIG.

  As described above, according to the second embodiment, when the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by molten Na. Nitrogen gas is introduced into the reaction vessel 103 when the nitrogen pressure in the reaction vessel 103 decreases. As a result, it becomes possible to achieve both the prevention of diffusion of Na to the outside of the reaction vessel 103 and the stable supply of the nitrogen raw material, and the stable growth of the GaN crystal is continued, and the low-cost, high-quality, large-size, and homogeneous GaN. Crystals can be produced.

  In addition, the pressure in the space 302 in the pressure vessel 301 and the pressure in the space 107 in the reaction vessel 103 can be made substantially equal to each other. Therefore, in the case of the manufacturing apparatus 100A, the reaction vessel 103 needs to satisfy both pressure resistance and heat resistance. However, in the manufacturing apparatus 100B according to the second embodiment, the reaction vessel 103 is required to have pressure resistance. Not. As a result, the thickness of the reaction vessel 103 can be reduced, the heat capacity of the reaction vessel 103 is reduced, and finer control of the temperature in the pressure vessel 301 is possible. As a result, the temperature fluctuation range in the pressure vessel 301 can be made smaller than that in the first embodiment, and stable GaN crystal growth is continued, and a high-quality, large-sized, and homogeneous GaN crystal can be produced at low cost. Can be manufactured.

[Embodiment 3]
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 10 shows a schematic configuration of a GaN crystal manufacturing apparatus 100C as a group III nitride crystal manufacturing apparatus according to Embodiment 3 of the present invention. In the following, the same reference numerals are used for the same or equivalent components as those in the first embodiment described above, and the description thereof is simplified or omitted.

  A manufacturing apparatus 100C shown in FIG. 10 includes a reaction vessel 103, a melt holding vessel 101, heaters 109, 110, and 111, a nitrogen gas supply source (nitrogen gas cylinder) 105, gas supply pipes 104 and 119, valves 115 and 120, A pressure sensor 108, a gas exhaust pipe 114, a vacuum pump 116, a pressure regulator 106, and the like are included. That is, the manufacturing apparatus 100C is obtained by removing the gas supply pipe 117 and the valve 118 from the manufacturing apparatus 100A according to the first embodiment.

Next, a method for manufacturing a GaN crystal using the manufacturing apparatus 100C configured as described above will be described.
(1) Close each valve.
(2) Separate the reaction vessel 103 from each pipe and place it in a glove box in an argon atmosphere.
(3) The melt holding container 101 is taken out from the reaction vessel 103, and raw material Ga and flux Na are put into the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(4) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103. Here, unlike the first and second embodiments, nothing is put in the gap between the reaction vessel 103 and the melt holding vessel 101.
(5) Close the lid of the reaction vessel 103.
(6) The reaction vessel 103 is taken out of the glove box and connected to each pipe as shown in FIG. 11 as an example. At this time, for example, nitrogen gas is flowed so that no air remains in each gas supply pipe. As a result, the gas supply pipe is filled with nitrogen gas.
(7) The vacuum pump 116 is operated.
(8) The valve 115 is opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 is discharged.
(9) With reference to the pressure sensor 108, when the pressure in the space portion 107 in the reaction vessel 103 reaches a predetermined pressure, the valve 115 is closed.
(10) Open the valve 120 and supply nitrogen gas into the reaction vessel 103. At this time, with reference to the pressure sensor 108, the pressure regulator 106 is controlled so that the pressure of the nitrogen gas in the reaction vessel 103 becomes approximately 15 atm.
(11) Energize the heaters 109 and 110 to raise the temperature in the melt holding vessel 101 and the reaction vessel 103 to 800 ° C. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

  When the temperature in the reaction vessel 103 rises, a part of Na in the mixed melt 102 evaporates and Na vapor exits into the space 107. This Na vapor moves to a low temperature region in the gas supply pipe 104. At this time, the heater 111 controls the temperature of the gas supply pipe 104 to a temperature at which substantial evaporation of Na does not occur, so that molten Na 501 adheres to the inside of the gas supply pipe 104 as shown in FIG. 11 as an example. . Here, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 113 of the gas supply pipe 104 are substantially equal to each other, the level of the gas-liquid interface A and the level of the gas-liquid interface B substantially coincide with each other. Yes.

In the temperature raising process of the reaction vessel 103, the pressure regulator 106 controls the pressure so that the pressure in the space 107 in the reaction vessel 103 and the pressure in the space 113 on the nitrogen cylinder side of the gas supply pipe 104 are substantially the same. While increasing the pressure to 40 atm.
(12) The temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure in the space 107 in the reaction vessel 103 decreases, the molten Na 501 reacts due to the differential pressure between the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103 as shown in FIG. 13 as an example. Move into the container 103. As a result, the gas-liquid interface A rises and the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104. At this time, the nitrogen gas becomes a bubble and rises in the molten Na 112 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 of the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. In this way, nitrogen gas is supplied from the nitrogen gas cylinder 105 to the space 107 of the reaction vessel 103 until the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other. When the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are approximately equal to each other, the level of the gas-liquid interface A and the level of the gas-liquid interface B are approximately equal to each other. In the process of crystal growth, the state shown in FIG. 12 and the state shown in FIG. 13 are repeated, and nitrogen gas is supplied to the space 107 in the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is 800 ° C. which is the same as the temperature in the reaction vessel 103. Since the Na vapor pressure at this temperature is as large as about 0.45 atm, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, as described above, the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate. Therefore, the Na vapor pressure is small, and Na is upstream from the gas-liquid interface B (nitrogen cylinder 105 side). It is negligible to spread to. Even if the molten Na in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. It adheres to the temperature-controlled region, becomes molten Na, and does not affect the introduction of nitrogen into the space 107 in the reaction vessel 103.

  In the manufacturing apparatus 100C, the GaN crystal is manufactured using the nitrogen gas pressure and the crystal growth temperature included in the regions REG1, REG2, and REG3 shown in FIG.

  As described above, according to the third embodiment, when the temperature in the reaction vessel 103 rises, a part of Na in the mixed melt 102 evaporates and condenses in the gas supply pipe 104. Then, the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103 are blocked. Thereafter, in the GaN crystal growth step, when the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by molten Na, Nitrogen gas is introduced into the reaction vessel 103 when the nitrogen pressure of the reactor decreases. As a result, stable growth of the GaN crystal is continued, and a high-quality, large-sized, and homogeneous GaN crystal can be manufactured at a low cost.

  Further, since the gas supply pipe 117 and the valve 118 are not required, the apparatus can be made simpler, the nitrogen pressure can be easily adjusted, the pressure controllability can be improved, and safer and more efficient crystal growth can be achieved. It becomes possible.

[Embodiment 4]
Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 14 shows a schematic configuration of a GaN crystal manufacturing apparatus 100D as a group III nitride crystal manufacturing apparatus according to Embodiment 4 of the present invention. In the following description, the same reference numerals are used for the same or equivalent components as those in the first embodiment, and the description thereof is simplified or omitted.

  14 includes a reaction vessel 103, a melt holding vessel 101, heaters 109, 110, 111, a nitrogen gas supply source (nitrogen gas cylinder) 105, gas supply pipes 104, 117, 119, and a valve 115. , 118, 120, pressure sensor 108, gas exhaust pipe 114, vacuum pump 116, pressure regulator 106, float 601 and the like. That is, manufacturing apparatus 100D is obtained by adding float 601 to manufacturing apparatus 100A in the first embodiment.

  This float 601 has a specific gravity smaller than that of molten Na and is made of a material that is inert to molten Na. The float 601 is a cylindrical member as an example, and the diameter thereof is smaller than the inner diameter of the gas supply pipe 104 and is arranged in the gas supply pipe 104. Therefore, the nitrogen gas can pass through the gap between the gas supply pipe 104 and the float 601.

Next, a method for manufacturing a GaN crystal using the manufacturing apparatus 100D configured as described above will be described.
(1) Close each valve.
(2) Separate the reaction vessel 103 from each pipe and place it in a glove box in an argon atmosphere.
(3) The melt holding container 101 is taken out from the reaction vessel 103, and raw material Ga and flux Na are put into the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(4) Molten Na is put into the reaction vessel 103.
(5) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103. As a result, the gap between the reaction vessel 103 and the melt holding vessel 101 is filled with molten Na.
(6) Close the lid of the reaction vessel 103.
(7) Take out the reaction vessel 103 from the glove box and connect it to each pipe. At this time, for example, nitrogen gas is flowed so that no air remains in each gas supply pipe. As a result, each gas supply pipe is filled with nitrogen gas.
(8) The vacuum pump 116 is operated.
(9) The valve 115 is opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 is discharged.
(10) With reference to the pressure sensor 108, when the pressure in the space 107 in the reaction vessel 103 reaches a predetermined pressure, the valve 115 is closed.
(11) Open the valve 118 and supply nitrogen gas into the reaction vessel 103. At this time, with reference to the pressure sensor 108, the pressure regulator 106 is controlled so that the pressure of the nitrogen gas in the reaction vessel 103 becomes approximately 15 atm. When the pressure in the reaction vessel 103 reaches 15 atmospheres, the valve 118 is closed. The above steps are performed at a temperature at which molten Na between the melt holding vessel 101 and the reaction vessel 103 maintains a liquid state, and at a temperature at which substantial evaporation of Na is suppressed (for example, 100 ° C.). .
(12) The valve 120 is opened. Thereby, as shown in FIG. 15 as an example, a part of the molten Na filling the gap between the reaction vessel 103 and the melt holding vessel 101 fills the U-shaped portion of the gas supply pipe 104. At this time, the float 601 rises in the gas supply pipe 104 while floating in the molten Na. Here, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 113 of the gas supply pipe 104 are substantially equal to each other, the level of the gas-liquid interface A and the level of the gas-liquid interface B substantially coincide with each other. Yes.
(13) The temperature in the melt holding vessel 101 and the reaction vessel 103 is raised to 800 ° C. by the heaters 109 and 110. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

  At this time, the heater 111 is controlled so that Na maintains a liquid state at the gas-liquid interface B and substantial evaporation of Na is suppressed. Therefore, the temperature of the gas-liquid interface A becomes higher than the temperature of the gas-liquid interface B, and a temperature gradient is generated between the gas-liquid interface A and the gas-liquid interface B.

In the temperature raising process of the reaction vessel 103, the pressure regulator 106 controls the pressure so that the pressure in the space 107 in the reaction vessel 103 and the pressure in the space 113 on the nitrogen cylinder side of the gas supply pipe 104 are substantially the same. While increasing the pressure to 40 atm.
(14) The temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure in the space 107 in the reaction vessel 103 decreases, as shown in FIG. 16 as an example, the molten Na 112 reacts due to the differential pressure between the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103. Move into the container 103. As a result, the gas-liquid interface A rises and the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104. At this time, the nitrogen gas becomes a bubble and rises in the molten Na 112 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 of the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. In this way, nitrogen gas is supplied from the nitrogen gas cylinder 105 to the space 107 of the reaction vessel 103 until the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other. When the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are approximately equal to each other, the level of the gas-liquid interface A and the level of the gas-liquid interface B are approximately equal to each other. In the process of crystal growth, the state shown in FIG. 15 and the state shown in FIG. 16 are repeated, and nitrogen gas is supplied to the space 107 in the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is 800 ° C. which is the same as the temperature in the reaction vessel 103. Since the Na vapor pressure at this temperature is as large as about 0.45 atm, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, as described above, the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate. Therefore, the Na vapor pressure is small, and Na is upstream from the gas-liquid interface B (nitrogen cylinder 105 side). It is negligible to spread to. Even if the molten Na in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. It adheres to the temperature-controlled region, becomes molten Na, and does not affect the introduction of nitrogen into the space 107 in the reaction vessel 103.

  In the manufacturing apparatus 100D, the GaN crystal is manufactured using the nitrogen gas pressure and the crystal growth temperature included in the regions REG1, REG2, and REG3 shown in FIG.

  As described above, according to the fourth embodiment, when the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by molten Na. Nitrogen gas is introduced into the reaction vessel 103 when the nitrogen pressure in the reaction vessel 103 decreases. As a result, it becomes possible to achieve both the prevention of diffusion of Na to the outside of the reaction vessel 103 and the stable supply of the nitrogen raw material, and the stable growth of the GaN crystal is continued, and the low-cost, high-quality, large-size, and homogeneous GaN. Crystals can be produced.

  Further, since the opening of the gas-liquid interface B is narrowed by the float 601, a slight amount of Na evaporation can be further reduced, and as a result, safety and stability of crystal growth can be further improved. .

[Embodiment 5]
Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 17 shows a schematic configuration of a GaN crystal manufacturing apparatus 100E as a group III nitride crystal manufacturing apparatus according to Embodiment 5 of the present invention. In the following description, the same reference numerals are used for the same or equivalent components as those in the first embodiment, and the description thereof is simplified or omitted.

  A manufacturing apparatus 100E shown in FIG. 17 includes a reaction vessel 103, a melt holding vessel 101, heaters 109, 110, 111, and 703, a nitrogen gas supply source (nitrogen gas cylinder) 105, and a gas supply pipe for supplying nitrogen gas. 104, 117, 119, nitrogen gas pressure regulator 106, argon gas supply source (argon gas cylinder) 705, gas supply pipe 701 for supplying argon gas, argon gas pressure regulator 706, valves 115, 118, 120, 708, pressure sensor 108, gas exhaust pipe 114, vacuum pump 116, and the like. That is, the manufacturing apparatus 100E is obtained by adding a heater 703, an argon gas cylinder 705, a gas supply pipe 701, a pressure regulator 706, and a valve 708 to the manufacturing apparatus 100A in the first embodiment.

  The gas supply pipe 701 is a pipe having a U-shaped portion for supplying argon gas into the reaction vessel 103. One end of the gas supply pipe 701 is connected to the argon gas cylinder 705 via the pressure regulator 706, and the other end is connected to an opening provided at the bottom of the reaction vessel 103.

  The heater 703 has a plurality of heating portions, is disposed adjacent to the rising portion and the bottom portion of the gas supply pipe 701 that are away from the reaction vessel 103, and is held by the U-shaped portion of the gas supply pipe 701. A temperature gradient that suppresses substantial evaporation of molten Na (liquid) is applied to the U-shaped portion.

  The valve 708 is provided in the middle of the gas supply pipe 701 and close to the reaction vessel 103.

  The pressure regulator 706 is provided in the middle of the gas supply pipe 701 and is used to adjust the pressure of the argon gas.

  Further, as shown in FIG. 18, the reaction vessel 103 can be separated from each pipe including each valve, and the reaction vessel 103 can be moved into the glove box and operated.

Next, a method for manufacturing a GaN crystal by the manufacturing apparatus 100E configured as described above will be described.
(1) Close each valve.
(2) Separate the reaction vessel 103 from each pipe and place it in a glove box in an argon atmosphere.
(3) The melt holding container 101 is taken out from the reaction vessel 103, and raw material Ga and flux Na are put into the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(4) Molten Na112 is put into the reaction vessel 103.
(5) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103. As a result, the gap between the reaction vessel 103 and the melt holding vessel 101 is filled with molten Na.
(6) Close the lid of the reaction vessel 103.
(7) Take out the reaction vessel 103 from the glove box and connect it to each pipe. At this time, for example, connection is made while flowing nitrogen gas so that no air remains in the nitrogen gas supply pipe. As a result, the inside of the gas supply pipe for nitrogen gas is filled with nitrogen gas. Further, for example, the argon gas is connected while flowing argon gas so that no air remains in the argon gas supply pipe 701. As a result, the argon gas supply pipe 701 is filled with the argon gas.
(8) The vacuum pump 116 is operated.
(9) The valve 115 is opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 is discharged.
(10) With reference to the pressure sensor 108, when the pressure in the space 107 in the reaction vessel 103 reaches a predetermined pressure, the valve 115 is closed.
(11) Open the valve 118 and supply nitrogen gas into the reaction vessel 103. At this time, with reference to the pressure sensor 108, the pressure regulator 106 is controlled so that the pressure of the nitrogen gas in the reaction vessel 103 becomes approximately 15 atm. When the pressure in the reaction vessel 103 reaches 15 atmospheres, the valve 118 is closed. The above steps are performed at a temperature at which molten Na between the melt holding vessel 101 and the reaction vessel 103 maintains a liquid state, and at a temperature at which substantial evaporation of Na is suppressed (for example, 100 ° C.). .
(12) The valve 120 and the valve 708 are opened. As a result, as shown in FIG. 19 as an example, a part of the molten Na filling the gap between the reaction vessel 103 and the melt holding vessel 101 is caused by the U-shaped portion of the gas supply pipe 104 and the gas supply pipe. Each of the U-shaped portions 701 is filled. At this time, the molten Na has three gas-liquid interfaces: a gas-liquid interface A in the reaction vessel 103, a gas-liquid interface B in the gas supply pipe 104, and a gas-liquid interface C in the gas supply pipe 701. It becomes. Here, the pressure of the space portion 107 in the reaction vessel 103, the pressure of the space portion 113 of the gas supply pipe 104, and the pressure of the space portion 702 of the gas supply pipe 701 are substantially equal to each other. The level of the liquid interface B and the level of the gas-liquid interface C are almost the same.
(13) The temperature in the melt holding vessel 101 and the reaction vessel 103 is raised to 800 ° C. by the heaters 109 and 110. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

  At this time, the heater 111 is controlled so that Na maintains a liquid state at the gas-liquid interface B and substantial evaporation of Na is suppressed. Therefore, the temperature of the gas-liquid interface A becomes higher than the temperature of the gas-liquid interface B, and a temperature gradient is generated between the gas-liquid interface A and the gas-liquid interface B. In addition, the heater 703 is controlled so that Na remains in a liquid state at the gas-liquid interface C and substantial evaporation of Na is suppressed. Accordingly, the temperature of the gas-liquid interface A becomes higher than the temperature of the gas-liquid interface C, and a temperature gradient is generated between the gas-liquid interface A and the gas-liquid interface C.

In the temperature raising process of the reaction vessel 103, the pressure of the space 107 in the reaction vessel 103, the pressure of the space 113 on the nitrogen cylinder side of the gas supply pipe 104, and the pressure of the space 702 on the argon cylinder 705 side of the gas supply pipe 701 The pressure in the space portion 107 in the reaction vessel 103 is increased to 40 atm while controlling the pressure by the pressure regulator 106 and the pressure regulator 706 so that the pressures are substantially the same.
(14) The temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure in the space 107 in the reaction vessel 103 decreases, as shown in FIG. 20 as an example, the differential pressure between the space 113 in the gas supply tube 104 and the space 107 in the reaction vessel 103, and the gas supply tube 701. Due to the differential pressure between the inner space 702 and the space 107 in the reaction vessel 103, the molten Na 112 moves into the reaction vessel 103. As a result, the gas-liquid interface A rises, the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104, and the gas-liquid interface C reaches to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 701. Moving. At this time, the nitrogen gas becomes a bubble and rises in the molten Na 112 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 of the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. In addition, the argon gas becomes a bubble and rises in the molten Na 112 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 702 of the gas supply pipe 701 and the space 107 in the reaction vessel 103 are continuously connected, and argon gas is supplied to the space 107 in the reaction vessel 103. In this manner, until the pressure in the space 113 of the gas supply pipe 104, the pressure in the space 702 of the gas supply pipe 701, and the pressure in the space 107 in the reaction container 103 are substantially equal to each other, Nitrogen gas is supplied to the space 107, and argon gas is supplied from the argon gas cylinder 705 to the space 107 of the reaction vessel 103. When the pressure in the space 113 of the gas supply pipe 104, the pressure in the space 702 of the gas supply pipe 701, and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, the level of the gas-liquid interface A and the level of the gas-liquid interface B The levels of the gas-liquid interface C are almost equal to each other. In the process of crystal growth, the state shown in FIG. 19 and the state shown in FIG. 20 are repeated, and nitrogen gas and argon gas are supplied to the space 107 of the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is 800 ° C. which is the same as the temperature in the reaction vessel 103. Since the Na vapor pressure at this temperature is as large as about 0.45 atm, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, as described above, the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate. Therefore, the Na vapor pressure is small, and Na is upstream from the gas-liquid interface B (nitrogen cylinder 105 side). It is negligible to spread to. Even if the molten Na in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. It adheres to the temperature-controlled region, becomes molten Na, and does not affect the introduction of nitrogen into the space 107 in the reaction vessel 103. Further, as described above, since the temperature of the gas-liquid interface C is maintained at a temperature at which substantial evaporation of Na does not occur, the Na vapor pressure is small, and Na is upstream from the gas-liquid interface C (argon gas cylinder 705 side). It is negligible to spread to. Even if the molten Na in the gas supply pipe 701 moves into the reaction vessel 103 and the gas-liquid interface C moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface C remains in the gas supply pipe 701. It adheres to the temperature-controlled region, becomes molten Na, and does not affect the introduction of argon gas into the space 107 in the reaction vessel 103.

  Also in the manufacturing apparatus 100E, GaN crystals are manufactured using the nitrogen gas pressure and the crystal growth temperature included in the regions REG1, REG2, and REG3 shown in FIG.

  As described above, according to the fifth embodiment, when the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by molten Na. Nitrogen gas is introduced when the nitrogen pressure in the reaction vessel 103 decreases. As a result, it becomes possible to achieve both the prevention of diffusion of Na to the outside of the reaction vessel 103 and the stable supply of the nitrogen raw material, and the stable growth of the GaN crystal is continued, and the low-cost, high-quality, large-size, and homogeneous GaN. Crystals can be produced.

  In addition, since plural types of gases are mixed in the reaction vessel 103, the nitrogen partial pressure and the total pressure in the reaction vessel 103 can be controlled separately. As a result, the controllable range of the nitrogen dissolution amount in the mixed melt 102 can be widened, and the controllability of crystal growth can be improved.

[Embodiment 6]
FIG. 21 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the sixth embodiment. Referring to FIG. 21, manufacturing apparatus 100F according to the sixth embodiment is the same as manufacturing apparatus 100A except that valve 120 of manufacturing apparatus 100A shown in FIG. 1 is replaced with valve 130 and heater 140 is added. It is.

  The valve 130 is attached to the gas supply pipe 104 in the vicinity of the connection portion between the gas supply pipe 104 and the gas supply pipe 117. Then, the valve 130 supplies nitrogen gas from the gas supply pipe 117 to the reaction container 103 side, or stops supply of nitrogen gas from the gas supply pipe 117 to the reaction container 103 side.

  The heater 140 is disposed around the rising portion 104 </ b> A of the gas supply pipe 104. In the heater 140, the vapor pressure of the metal Na evaporating from the molten Na stored in a part of the gas supply pipe 104 substantially matches the vapor pressure of the metal Na evaporating from the mixed melt 102 in the melt holding container 101. The rising portion 104A of the gas supply pipe 104 is heated to a specific temperature.

  FIG. 22 is a timing chart of temperatures of the melt holding container 101, the reaction container 103, and the gas supply pipe 104. FIG. 23 is a schematic diagram showing changes in the state of the melt holding container 101 and the reaction container 103 at the timing t1 and the timing t2 shown in FIG.

  In FIG. 22, a straight line k1 indicates the temperature of the melt holding container 101 and the reaction container 103, and a curved line k2 and a straight line k3 indicate the temperature of the molten Na in the gas supply pipe 104.

  Referring to FIG. 22, heaters 109 and 110 heat melt holding container 101 and reaction container 103 so that the temperature rises according to straight line k <b> 1 and is maintained at 800 ° C. Further, the heater 140 heats the rising portion 104A of the gas supply pipe 104 so that the temperature rises according to the curve k2 and is held at the specific temperature Tsp1. Furthermore, the heater 111 heats the rising portion 104B and the horizontal portion 104C of the gas supply pipe 104 so that the temperature rises according to the curve k3 and is maintained at the specific temperature Tsp2.

  When the heaters 109 and 110 start to heat the melt holding container 101 and the reaction container 103 and the heaters 111 and 140 start to heat the gas supply pipe 104, molten Na 122 exists in the gas supply pipe 104. In the melt holding container 101, there is a mixed melt 102 containing metal Na and metal Ga (see FIG. 23A).

  Then, the temperatures of the melt holding container 101 and the reaction container 103 reach 98 ° C. at timing t1, and reach 800 ° C. at timing t2. The rising portion 104A of the gas supply pipe 104 reaches the specific temperature Tsp1 at the timing t2, and the rising portion 104B reaches the specific temperature Tsp2 at the timing t2. The specific temperature Tsp1 is a temperature at which the vapor pressure PNa1 of the metal Na evaporating from the molten Na 122 substantially matches the vapor pressure PNa-Ga of the metal Na evaporating from the mixed melt 102. The specific temperature Tsp2 is a temperature at which substantial evaporation of Na from the molten Na accumulated in the gas supply pipe 104 is suppressed as described in the first to fifth embodiments. The specific temperature Tsp1 is lower than 800 ° C., and the specific temperature Tsp2 is lower than the specific temperature Tsp1.

Accordingly, the rising portion 104A of the gas supply pipe 104 is heated by the heater 140 to a specific temperature Tsp1 at which the evaporation of the metal Na from the molten Na 122 and the evaporation of the metal Na from the mixed melt 102 are substantially in equilibrium ( (See (b) of FIG. 23). The rising portion 104B of the gas supply pipe 104 is heated by the heater 111 to a specific temperature Tsp2 at which the evaporation of metal Na from the molten Na 122 does not substantially occur. In this case, the vapor pressure of the metal Na in the rising portion 104B of the gas supply pipe 104 is PNa2, and is 7.6 × 10 ⁻⁹ atmospheric pressure and 1.8 × 10 ^{− −} described in the first to fifth embodiments. Low vapor pressure such as ⁵ and 4.7 × 10 ⁻⁴ atm.

  As a result, the vapor phase transport of the metal Na from the molten Na 122 to the mixed melt 102 and the vapor phase transport of the metal Na from the mixed melt 102 to the molten Na 122 are substantially equilibrated. The vapor transport of metal Na to and from the liquid 102 is stopped. And the fluctuation | variation of the mixing ratio of the metal Na and the metal Ga in the mixed melt 102 by evaporation of the metal Na from molten Na122 and the mixed melt 102 is suppressed.

Next, with reference to FIGS. 24 to 26, a method for manufacturing a GaN crystal by the manufacturing apparatus 100F will be described. In the manufacturing apparatus 100F, as shown in FIG. 24, the reaction vessel 103 and the gas supply pipe 104 can be separated from each pipe including each valve, and the reaction vessel 103 and the gas supply pipe 104 are connected to each other. It is possible to work by moving it into a glove box (not shown).
(1) Close each valve.
(2) The reaction vessel 103 and the gas supply pipe 104 are separated from each pipe and placed in a glove box having an argon (Ar) atmosphere.
(3) Open the lid of the reaction vessel 103 and take out the melt holding vessel 101 from the reaction vessel 103. Then, the raw material Ga and the flux Na are placed in the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(4) Put molten Na 122 into the gas supply pipe 104.
(5) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103. Note that the reaction of oxygen and moisture with Ga and Na can be prevented by handling Ga and Na in an argon atmosphere.
(6) Close the lid of the reaction vessel 103.
(7) The reaction vessel 103 and the gas supply pipe 104 are taken out of the glove box and connected to each pipe. At this time, for example, nitrogen gas is flowed so that no air remains in each gas supply pipe. As a result, each gas supply pipe is filled with nitrogen gas. At this time, as shown in FIG. 23A, the mixed melt 102 is held in the melt holding device 101, and the molten Na 122 is held in the gas supply pipe 104.
(8) The vacuum pump 116 is operated.
(9) The valve 115 is opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 is discharged. That is, the gas purge in the reaction vessel 103 is performed. (10) With reference to the pressure sensor 108, when the pressure in the space 107 in the reaction vessel 103 reaches a predetermined pressure, the valve 115 is closed.
(11) The valves 118 and 130 are opened, and nitrogen gas is supplied into the reaction vessel 103. At this time, referring to the pressure sensor 108, the pressure regulator 106 is adjusted so that the pressure of the nitrogen gas in the reaction vessel 103 is approximately 15 atm. When the pressure in the reaction vessel 103 reaches 15 atmospheres, the valve 118 is closed. Each of the above steps is performed at a temperature at which the molten Na 122 in the gas supply pipe 104 maintains a liquid state.
(12) The temperature in the reaction vessel 103 is raised to 800 ° C. by the heaters 109 and 110. Further, the heaters 111 and 140 are energized, the rising portion 104A of the gas supply pipe 104 is heated to the specific temperature Tsp1, and the rising portion 104B of the gas supply pipe 104 is heated to the specific temperature Tsp2. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

  At this time, as shown in FIG. 25, the molten Na 122 has two gas-liquid interfaces A and B in the gas supply pipe 104. Here, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 113 in the gas supply pipe 104 are substantially equal to each other, the level L1 of the gas-liquid interface A and the level L2 of the gas-liquid interface B are almost equal to each other. Match.

  The vapor pressure PNa1 of metal Na at the gas-liquid interface A substantially matches the vapor pressure PNa-Ga of metal Na evaporated from the mixed melt 102. The fact that the vapor pressure PNa1 substantially matches the vapor pressure PNa-Ga means that the vapor phase transport of metal Na from the molten Na 122 to the mixed melt 102 is different from the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 122. This means that an equilibrium state has been reached, and the reduction of metallic Na from the mixed melt 102 is prevented.

  The vapor pressure PNa2 of the metal Na at the gas-liquid interface B is maintained at a vapor pressure at which the metal Na does not substantially evaporate from the molten Na122.

  Therefore, the gas-liquid interface A of the molten Na 122 held in the gas supply pipe 104 is set to a temperature that prevents the decrease of metal Na from the mixed melt 102, and the gas-liquid interface B of the molten Na 122 is from the molten Na 122. The temperature is set so that the evaporation of the metal Na is substantially suppressed.

In the temperature raising process of the reaction vessel 103 and the gas supply pipe 104, the pressure in the space 107 in the reaction vessel 103 and the pressure in the space 113 on the nitrogen cylinder side of the gas supply pipe 104 are almost the same. While the pressure is controlled by the regulator 106, the pressure is increased to 40 atmospheres.
(13) The temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure in the space 107 in the reaction vessel 103 decreases, as shown in FIG. 26 as an example, due to the differential pressure between the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103, the molten Na 122 It moves into the reaction vessel 103. As a result, the gas-liquid interface A rises and the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104. At this time, the nitrogen gas is foamed and rises in the molten Na 122 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 of the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. In this way, nitrogen gas is supplied from the nitrogen gas cylinder 105 to the space 107 in the reaction vessel 103 until the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other. . When the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are approximately equal to each other, the level of the gas-liquid interface A and the level of the gas-liquid interface B are approximately equal to each other. In the process of crystal growth, the state shown in FIG. 25 and the state shown in FIG. 26 are repeated, and nitrogen gas is supplied to the space 107 in the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is set to a specific temperature Tsp1 at which the vapor phase transport of metal Na from the molten Na 122 to the mixed melt 102 is in equilibrium with the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 122. Is set. Therefore, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, since the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate as described above, the Na vapor pressure is small and Na is upstream from the gas-liquid interface B (on the side of the nitrogen cylinder 105). ) Can be ignored. Even if the molten Na 122 in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. Since it adheres to the temperature-controlled region and is liquefied there, it does not affect the introduction of nitrogen gas into the space 107 in the reaction vessel 103.

  In manufacturing apparatus 100F, various GaN crystals are manufactured using the nitrogen gas pressure and crystal growth temperature contained in regions REG1, REG2, and REG3 shown in FIG.

  As described above, according to the sixth embodiment, when the pressure in the space 113 of the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by the molten Na 122. Nitrogen gas is introduced into the reaction vessel 103 when the nitrogen pressure in the reaction vessel 103 decreases.

  Further, the vapor pressure PNa1 of the metal Na at the gas-liquid interface A on the reaction vessel 103 side of the molten Na 122 held in the gas supply pipe 104 substantially matches the vapor pressure PNa-Ga of the metal Na evaporating from the mixed melt 102. To do.

  As a result, while preventing diffusion of metal Na to the outside of the reaction vessel 103, the mixing ratio of metal Na and metal Ga in the mixed melt 102 can be kept substantially constant, and a stable supply of nitrogen raw material can be achieved at the same time. It becomes possible. And the growth of the stable GaN crystal is continued, and a high quality, large size, and homogeneous GaN crystal can be manufactured at low cost. Therefore, it is possible to grow a large group III nitride crystal with higher quality than the conventional flux method.

  Others are the same as in the first embodiment.

[Embodiment 7]
FIG. 27 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the seventh embodiment. Referring to FIG. 27, manufacturing apparatus 100G according to the seventh embodiment is the same as manufacturing apparatus 100B except that heater 120 is added instead of valve 130 in manufacturing apparatus 100B shown in FIG. It is.

  The valve 130 and the heater 140 are as described in the sixth embodiment.

Next, with reference to FIG. 28 and FIG. 29, the manufacturing method of the GaN crystal by the manufacturing apparatus 100G is demonstrated.
(1) Close each valve.
(2) The reaction vessel 103 and the gas supply pipe 104 are disconnected from each pipe, and the reaction vessel 103 is taken out from the pressure vessel 301.
(3) The taken-out reaction vessel 103 and gas supply pipe 104 are placed in a glove box in an argon atmosphere.
(4) The melt holding container 101 is taken out from the reaction vessel 103, and raw material Ga and flux Na are put into the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(5) Put molten Na into the gas supply pipe 104.
(6) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103.
(7) Close the lid of the reaction vessel 103.
(8) Take out the reaction vessel 103 and the gas supply pipe 104 from the glove box and store them in a predetermined position in the pressure vessel 301.
(9) The reaction vessel 103 and the gas supply pipe 104 are connected to each pipe. At this time, for example, nitrogen gas is flowed so that no air remains in each gas supply pipe. As a result, each gas supply pipe is filled with nitrogen gas.
(10) Close the lid of the pressure vessel 301.
(11) The vacuum pump 116 is operated.
(12) The valves 115 and 307 are opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 and the gas existing in the space portion 302 between the pressure vessel 301 and the reaction vessel 103 are discharged.
(13) With reference to the pressure sensors 108 and 304, when the pressure in the space portion 107 in the reaction vessel 103 and the pressure in the space portion 302 between the pressure vessel 301 and the reaction vessel 103 reach a predetermined pressure, the valve 115, 307 is closed.
(14) The valves 118, 130, and 305 are opened, and nitrogen gas is supplied into the reaction vessel 103 and the pressure vessel 301. At this time, referring to the pressure sensors 108 and 304, the pressure regulator 106 is controlled so that the pressure of the nitrogen gas in the reaction vessel 103 and the pressure vessel 301 is approximately 15 atm. When the pressure in the reaction vessel 103 and the pressure vessel 301 reaches 15 atmospheres, the valve 305 is kept open and the valve 118 is closed. The above steps are performed at a temperature at which the molten Na 122 in the gas supply pipe 104 maintains a liquid state and a temperature at which substantial evaporation of Na is suppressed (for example, 100 ° C.).
(15) The temperature in the reaction vessel 103 is raised to 800 ° C. by the heaters 109 and 110. Further, the heaters 111 and 140 are energized, the rising portion 104A of the gas supply pipe 104 is heated to the specific temperature Tsp1, and the rising portion 104B of the gas supply pipe 104 is heated to the specific temperature Tsp2. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

  At this time, as shown in FIG. 28, the molten Na 122 has two gas-liquid interfaces A and B in the gas supply pipe 104. Here, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 113 of the gas supply pipe 104 are substantially equal to each other, the level L1 of the gas-liquid interface A and the level L2 of the gas-liquid interface B are substantially equal to each other. I'm doing it.

  The vapor pressure PNa1 of metal Na at the gas-liquid interface A substantially matches the vapor pressure PNa-Ga of metal Na evaporated from the mixed melt 102. The fact that the vapor pressure PNa1 substantially matches the vapor pressure PNa-Ga means that the vapor phase transport of metal Na from the molten Na 122 to the mixed melt 102 is different from the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 122. This means that an equilibrium state has been reached, and the reduction of metallic Na from the mixed melt 102 is prevented.

  The vapor pressure PNa2 of the metal Na at the gas-liquid interface B is maintained at a vapor pressure at which the metal Na does not substantially evaporate from the molten Na122.

  Therefore, the gas-liquid interface A of the molten Na 122 held in the gas supply pipe 104 is set to a temperature that prevents the decrease of metal Na from the mixed melt 102, and the gas-liquid interface B of the molten Na 122 is from the molten Na 122. The temperature is set so that the evaporation of the metal Na is substantially suppressed.

In the temperature raising process of the reaction vessel 103 and the gas supply pipe 104, the pressure in the space 107 in the reaction vessel 103, the pressure in the space 113 on the nitrogen cylinder side of the gas supply pipe 104, and the pressure in the space 302 in the pressure vessel 301 are used. The pressure is increased to 40 atmospheres while controlling the pressure by the pressure regulator 106 so that the two are substantially the same.
(16) The temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure of the space 107 in the reaction vessel 103 decreases, as shown in FIG. 29 as an example, the molten Na 122 is caused by the differential pressure between the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103. It moves into the reaction vessel 103. As a result, the gas-liquid interface A rises and the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104. At this time, the nitrogen gas is foamed and rises in the molten Na 122 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. In this way, nitrogen gas is supplied from the nitrogen gas cylinder 105 to the space 107 of the reaction vessel 103 until the pressure of the space 113 in the gas supply pipe 104 and the pressure of the space 107 in the reaction vessel 103 are substantially equal to each other. . When the pressure in the space 113 in the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, the level at the gas-liquid interface A and the level at the gas-liquid interface B are approximately equal to each other. In the process of crystal growth, the state shown in FIG. 28 and the state shown in FIG. 29 are repeated, and nitrogen gas is supplied to the space 107 in the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is set to a specific temperature Tsp1 at which the vapor phase transport of metal Na from the molten Na 122 to the mixed melt 102 is in equilibrium with the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 122. Is set. Therefore, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, since the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate as described above, the Na vapor pressure is small and Na is upstream from the gas-liquid interface B (on the side of the nitrogen cylinder 105). ) Can be ignored. Even if the molten Na 122 in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. Since it adheres to the temperature-controlled region and is liquefied there, it does not affect the introduction of nitrogen gas into the space 107 in the reaction vessel 103.

  In manufacturing apparatus 100G, various GaN crystals are manufactured using the nitrogen gas pressure and crystal growth temperature contained in regions REG1, REG2, and REG3 shown in FIG.

  As described above, according to the seventh embodiment, when the pressure in the space 113 in the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by the molten Na 122. When the nitrogen pressure in the reaction vessel 103 is reduced, nitrogen gas is introduced into the reaction vessel 103.

  Further, the vapor pressure PNa1 of the metal Na at the gas-liquid interface A on the reaction vessel 103 side of the molten Na 122 held in the gas supply pipe 104 substantially matches the vapor pressure PNa-Ga of the metal Na evaporating from the mixed melt 102. To do.

  As a result, while preventing diffusion of metal Na to the outside of the reaction vessel 103, the mixing ratio of metal Na and metal Ga in the mixed melt 102 can be kept substantially constant, and a stable supply of nitrogen raw material can be achieved at the same time. It becomes possible. And the growth of the stable GaN crystal is continued, and a high quality, large size, and homogeneous GaN crystal can be manufactured at low cost. Therefore, it is possible to grow a large group III nitride crystal with higher quality than the conventional flux method.

  Others are the same as in the first and second embodiments.

[Embodiment 8]
FIG. 30 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the eighth embodiment. Referring to FIG. 30, manufacturing apparatus 100J according to the eighth embodiment is the same as manufacturing apparatus 100C except that heater 120 is added instead of valve 130 in manufacturing apparatus 100C shown in FIG. It is.

  The valve 130 and the heater 140 are as described in the sixth embodiment.

Next, with reference to FIGS. 31 to 33, a method of manufacturing a GaN crystal by the manufacturing apparatus 100J will be described.
(1) Close each valve.
(2) The reaction vessel 103 and the gas supply pipe 104 are separated from each pipe and placed in a glove box in an argon atmosphere.
(3) The melt holding container 101 is taken out from the reaction vessel 103, and raw material Ga and flux Na are put into the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(4) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103. In this case, unlike the sixth and seventh embodiments described above, the melt holding device 101 is accommodated in the reaction vessel 103 in a state where molten Na is not put into the gas supply pipe 104.
(5) Close the lid of the reaction vessel 103.
(6) The reaction vessel 103 and the gas supply pipe 104 are taken out of the glove box and connected to each pipe as shown in FIG. 31 as an example. At this time, for example, nitrogen gas is flowed so that no air remains in each gas supply pipe. As a result, the gas supply pipe is filled with nitrogen gas.
(7) The vacuum pump 116 is operated.
(8) The valve 115 is opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 is discharged.
(9) With reference to the pressure sensor 108, when the pressure in the space portion 107 in the reaction vessel 103 reaches a predetermined pressure, the valve 115 is closed.
(10) Open the valve 130 and supply nitrogen gas into the reaction vessel 103. At this time, since the metal Na is not accumulated in the gas supply pipe 104, the nitrogen gas is supplied to the space portion 107 in the reaction vessel 103 through the gas supply pipe 104. Further, referring to the pressure sensor 108, the pressure regulator 106 is controlled so that the pressure of the nitrogen gas in the reaction vessel 103 becomes approximately 15 atm.
(11) Energize the heaters 109 and 110 to raise the temperature in the reaction vessel 103 to 800 ° C. Further, the heaters 111 and 140 are energized, the rising portion 104A of the gas supply pipe 104 is heated to the specific temperature Tsp1, and the rising portion 104B of the gas supply pipe 104 is heated to the specific temperature Tsp2. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

  When energization of the heaters 109, 110, 111, and 140 is started, as shown in FIG. 31, the mixed melt 102 is held in the melt holding container 101, and molten Na is not accumulated in the gas supply pipe 104. State.

  Thereafter, as the temperature of the melt holding vessel 101 and the reaction vessel 103 approaches 800 ° C., the amount of metal Na evaporated from the mixed melt 102 increases, and the metal Na evaporated from the mixed melt 102 is in a liquid state. In the gas supply pipe 104 which may be present in At this point in time, as shown in FIG. 32, the molten Na 122 accumulated in the gas supply pipe 104 has two gas-liquid interfaces A and B in the gas supply pipe 104. Here, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 113 in the gas supply pipe 104 are substantially equal to each other, the level L1 of the gas-liquid interface A and the level L2 of the gas-liquid interface B are almost equal to each other. Match.

  The rising portion 104A of the gas supply pipe 104 is heated to the specific temperature Tsp1, and the rising portion 104B of the gas supply pipe 104 is heated to the specific temperature Tsp2, so that the vapor pressure PNa1 of the metal Na at the gas-liquid interface A Is substantially equal to the vapor pressure PNa-Ga of metal Na evaporating from the mixed melt 102. The fact that the vapor pressure PNa1 substantially matches the vapor pressure PNa-Ga means that the vapor phase transport of metal Na from the molten Na 122 to the mixed melt 102 is different from the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 122. This means that an equilibrium state has been reached, and the reduction of metallic Na from the mixed melt 102 is prevented.

  The vapor pressure PNa2 of the metal Na at the gas-liquid interface B is maintained at a vapor pressure at which the metal Na does not substantially evaporate from the molten Na122.

  Therefore, the gas-liquid interface A of the molten Na 122 held in the gas supply pipe 104 is set to a temperature that prevents the decrease of metal Na from the mixed melt 102, and the gas-liquid interface B of the molten Na 122 is from the molten Na 122. The temperature is set so that the evaporation of the metal Na is substantially suppressed.

In the temperature raising process of the reaction vessel 103 and the gas supply pipe 104, the pressure in the space 107 in the reaction vessel 103 and the pressure in the space 113 on the nitrogen cylinder side of the gas supply pipe 104 are almost the same. While the pressure is controlled by the regulator 106, the pressure is increased to 40 atmospheres.
(12) When the temperature in the reaction vessel 103 reaches 800 ° C., the temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure in the space 107 in the reaction vessel 103 decreases, as shown in FIG. 33 as an example, the molten Na 122 is caused by the differential pressure between the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103. It moves into the reaction vessel 103. As a result, the gas-liquid interface A rises and the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104. At this time, the nitrogen gas is foamed and rises in the molten Na 122 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. In this way, nitrogen gas is supplied from the nitrogen gas cylinder 105 to the space 107 in the reaction vessel 103 until the pressure in the space 113 in the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other. The When the pressure in the space 113 in the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, the level at the gas-liquid interface A and the level at the gas-liquid interface B are approximately equal to each other. In the process of crystal growth, the state shown in FIG. 32 and the state shown in FIG. 33 are repeated, and nitrogen gas is supplied to the space 107 in the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is set to a specific temperature Tsp1 at which the vapor phase transport of metal Na from the molten Na 122 to the mixed melt 102 is in equilibrium with the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 122. Is set. Therefore, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, since the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate as described above, the Na vapor pressure is small and Na is upstream from the gas-liquid interface B (on the side of the nitrogen cylinder 105). ) Can be ignored. Even if the molten Na 122 in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. Since it adheres to the temperature-controlled region and is liquefied there, it does not affect the introduction of nitrogen gas into the space 107 in the reaction vessel 103.

  In manufacturing apparatus 100J, various GaN crystals are manufactured using the nitrogen gas pressure and crystal growth temperature included in regions REG1, REG2, and REG3 shown in FIG.

  As described above, according to the eighth embodiment, when the temperature in the reaction vessel 103 rises, a part of Na in the mixed melt 102 evaporates and condenses in the gas supply pipe 104. Then, the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103 are blocked by the molten Na 122. Thereafter, in the GaN crystal growth step, when the pressure in the space 113 in the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by molten Na 122, and the reaction vessel 103 Nitrogen gas is introduced into the reaction vessel 103 when the nitrogen pressure inside the reactor decreases.

  Further, the vapor pressure PNa1 of the metal Na at the gas-liquid interface A on the reaction vessel 103 side of the molten Na 122 held in the gas supply pipe 104 substantially matches the vapor pressure PNa-Ga of the metal Na evaporating from the mixed melt 102. To do.

  As a result, while preventing diffusion of metal Na to the outside of the reaction vessel 103, the mixing ratio of metal Na and metal Ga in the mixed melt 102 can be kept substantially constant, and a stable supply of nitrogen raw material can be achieved at the same time. It becomes possible. And the growth of the stable GaN crystal is continued, and a high quality, large size, and homogeneous GaN crystal can be manufactured at low cost. Therefore, it is possible to grow a large group III nitride crystal with higher quality than the conventional flux method.

  Others are the same as in the first and third embodiments.

[Embodiment 9]
FIG. 34 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the ninth embodiment. Referring to FIG. 34, manufacturing apparatus 100K according to Embodiment 9 is the same as manufacturing apparatus 100D except that valve 120 of manufacturing apparatus 100D shown in FIG. 14 is replaced with valve 130 and heater 140 is added. It is.

  The valve 130 and the heater 140 are as described in the sixth embodiment.

Next, with reference to FIG. 35 and FIG. 36, the manufacturing method of the GaN crystal by the manufacturing apparatus 100K is demonstrated.
(1) Close each valve.
(2) The reaction vessel 103 and the gas supply pipe 104 are separated from each pipe and placed in a glove box in an argon atmosphere.
(3) The melt holding container 101 is taken out from the reaction vessel 103, and raw material Ga and flux Na are put into the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(4) Put molten Na into the gas supply pipe 104.
(5) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103.
(6) Close the lid of the reaction vessel 103.
(7) The reaction vessel 103 and the gas supply pipe 104 are taken out of the glove box and connected to each pipe. At this time, for example, nitrogen gas is flowed so that no air remains in each gas supply pipe. As a result, each gas supply pipe is filled with nitrogen gas.
(8) The vacuum pump 116 is operated.
(9) The valve 115 is opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 is discharged.
(10) With reference to the pressure sensor 108, when the pressure in the space 107 in the reaction vessel 103 reaches a predetermined pressure, the valve 115 is closed.
(11) The valves 118 and 130 are opened, and nitrogen gas is supplied into the reaction vessel 103. At this time, with reference to the pressure sensor 108, the pressure regulator 106 is controlled so that the pressure of the nitrogen gas in the reaction vessel 103 becomes approximately 15 atm. When the pressure in the reaction vessel 103 reaches 15 atmospheres, the valve 118 is closed. The above steps are performed at a temperature at which the molten Na 122 in the gas supply pipe 104 maintains a liquid state and a temperature at which substantial evaporation of Na is suppressed (for example, 100 ° C.).
(12) The temperature in the reaction vessel 103 is raised to 800 ° C. by the heaters 109 and 110. Further, the heaters 111 and 140 are energized, the rising portion 104A of the gas supply pipe 104 is heated to the specific temperature Tsp1, and the rising portion 104B of the gas supply pipe 104 is heated to the specific temperature Tsp2. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

  At this time, as shown in FIG. 35, the molten Na 122 has two gas-liquid interfaces A and B in the gas supply pipe 104. The float 601 floats on the gas-liquid interface B of the molten Na122. Here, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 113 in the gas supply pipe 104 are substantially equal to each other, the level L1 of the gas-liquid interface A and the level L2 of the gas-liquid interface B are almost equal to each other. Match.

  The vapor pressure PNa1 of metal Na at the gas-liquid interface A substantially matches the vapor pressure PNa-Ga of metal Na evaporated from the mixed melt 102. The fact that the vapor pressure PNa1 substantially matches the vapor pressure PNa-Ga means that the vapor phase transport of metal Na from the molten Na 122 to the mixed melt 102 is different from the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 122. This means that an equilibrium state has been reached, and the reduction of metallic Na from the mixed melt 102 is prevented.

  The vapor pressure PNa2 of the metal Na at the gas-liquid interface B is maintained at a vapor pressure at which the metal Na does not substantially evaporate from the molten Na122.

  Therefore, the gas-liquid interface A of the molten Na 122 held in the gas supply pipe 104 is set to a temperature that prevents the decrease of metal Na from the mixed melt 102, and the gas-liquid interface B of the molten Na 122 is from the molten Na 122. The temperature is set so that the evaporation of the metal Na is substantially suppressed.

In the temperature raising process of the reaction vessel 103 and the gas supply pipe 104, the pressure in the space 107 in the reaction vessel 103 and the pressure in the space 113 on the nitrogen cylinder side of the gas supply pipe 104 are almost the same. While the pressure is controlled by the regulator 106, the pressure is increased to 40 atmospheres.
(13) The temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure in the space 107 in the reaction vessel 103 decreases, as shown in FIG. 36 as an example, the molten Na 122 is caused by the differential pressure between the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103. It moves into the reaction vessel 103. As a result, the gas-liquid interface A rises and the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104. At this time, the nitrogen gas is foamed and rises in the molten Na 122 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. In this way, nitrogen gas is supplied from the nitrogen gas cylinder 105 to the space 107 in the reaction vessel 103 until the pressure in the space 113 in the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other. The When the pressure in the space 113 in the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, the level at the gas-liquid interface A and the level at the gas-liquid interface B are approximately equal to each other. In the process of crystal growth, the state shown in FIG. 35 and the state shown in FIG. 36 are repeated, and nitrogen gas is supplied to the space 107 in the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is set to a specific temperature Tsp1 at which the vapor phase transport of metal Na from the molten Na 122 to the mixed melt 102 is in equilibrium with the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 122. Is set. Therefore, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, since the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate as described above, the Na vapor pressure is small and Na is upstream from the gas-liquid interface B (on the side of the nitrogen cylinder 105). ) Can be ignored. Even if the molten Na 122 in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. Since it adheres to the temperature-controlled region and is liquefied there, it does not affect the introduction of nitrogen gas into the space 107 in the reaction vessel 103.

  In manufacturing apparatus 100K, various GaN crystals are manufactured using the nitrogen gas pressure and crystal growth temperature contained in regions REG1, REG2, and REG3 shown in FIG.

  As described above, according to the ninth embodiment, when the pressure in the space 113 in the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by the molten Na 122. When the nitrogen pressure in the reaction vessel 103 is reduced, nitrogen gas is introduced into the reaction vessel 103.

  Further, the vapor pressure PNa1 of the metal Na at the gas-liquid interface A on the reaction vessel 103 side of the molten Na 122 held in the gas supply pipe 104 substantially matches the vapor pressure PNa-Ga of the metal Na evaporating from the mixed melt 102. To do.

  As a result, while preventing diffusion of metal Na to the outside of the reaction vessel 103, the mixing ratio of metal Na and metal Ga in the mixed melt 102 can be kept substantially constant, and a stable supply of nitrogen raw material can be achieved at the same time. It becomes possible. And the growth of the stable GaN crystal is continued, and a high quality, large size, and homogeneous GaN crystal can be manufactured at low cost. Therefore, it is possible to grow a large group III nitride crystal with higher quality than the conventional flux method.

  Others are the same as in the first and fourth embodiments.

[Embodiment 10]
FIG. 37 is a schematic diagram showing a configuration of a GaN crystal manufacturing apparatus according to the tenth embodiment. Referring to FIG. 37, manufacturing apparatus 100L according to the tenth embodiment is obtained by replacing valves 120 and 708 of manufacturing apparatus 100E shown in FIG. 17 with valves 130 and 710, respectively, and adding heaters 141 to 143. Is the same as the manufacturing apparatus 100E.

  The valve 130 is as described in the sixth embodiment. The valve 710 is attached to the gas supply pipe 701 in the vicinity of the pressure regulator 706. Then, the valve 710 supplies argon gas from the gas cylinder 705 to the reaction container 103 side, or stops supplying argon gas from the gas cylinder 705 to the reaction container 103 side.

  The heater 141 is disposed to face the rising portion 104A of the gas supply pipe 104, the heater 142 is disposed to face the rising portion 104A of the gas supply pipe 104 and the rising portion 701A of the gas supply pipe 701, and the heater 143 is The gas supply pipe 701 is disposed to face the rising portion 701A.

  The heaters 141 and 142 are configured such that the vapor pressure of the metal Na evaporating from the molten Na stored in a part of the gas supply pipe 104 is changed to the vapor pressure of the metal Na evaporating from the mixed melt 102 in the melt holding container 101. The rising portion 104A of the gas supply pipe 104 is heated to a specific temperature Tsp1 that substantially matches. Further, the heaters 142 and 143 are configured such that the vapor pressure of the metal Na evaporating from the molten Na stored in a part of the gas supply pipe 701 is changed to the vapor pressure of the metal Na evaporating from the mixed melt 102 in the melt holding container 101. The rising portion 701A of the gas supply pipe 701 is heated to a specific temperature Tsp1 that substantially matches.

Next, with reference to FIGS. 38 to 40, a method of manufacturing a GaN crystal by the manufacturing apparatus 100L will be described. In the manufacturing apparatus 100L, as shown in FIG. 38, the reaction vessel 103 and the gas supply pipes 104 and 701 can be separated from each pipe including the respective valves. It is possible to work by moving 104 and 701 into a glove box (not shown).
(1) Close each valve.
(2) The reaction vessel 103 and the gas supply pipes 104 and 701 are separated from each pipe and placed in a glove box with an argon atmosphere.
(3) The melt holding container 101 is taken out from the reaction vessel 103, and raw material Ga and flux Na are put into the melt holding container 101. Here, as an example, the molar ratio of Na and Ga was set to 5: 5.
(4) The molten Na 122 and 712 are put into the gas supply pipes 104 and 701.
(5) The melt holding container 101 is accommodated in a predetermined position in the reaction container 103.
(6) Close the lid of the reaction vessel 103.
(7) The reaction vessel 103 and the gas supply pipes 104 and 701 are taken out of the glove box and connected to each pipe. At this time, for example, the connection is made while flowing nitrogen gas so that air does not remain in the nitrogen gas supply pipe 104. As a result, the inside of the nitrogen gas supply pipe 104 is filled with nitrogen gas. Further, for example, the argon gas is connected while flowing argon gas so that no air remains in the argon gas supply pipe 701. As a result, the argon gas supply pipe 701 is filled with the argon gas.
(8) The vacuum pump 116 is operated.
(9) The valve 115 is opened. Thereby, the argon gas contained in the space portion 107 in the reaction vessel 103 is discharged.
(10) With reference to the pressure sensor 108, when the pressure in the space 107 in the reaction vessel 103 reaches a predetermined pressure, the valve 115 is closed.
(11) The valves 118 and 130 are opened, and nitrogen gas is supplied into the reaction vessel 103. At this time, with reference to the pressure sensor 108, the pressure regulator 106 is controlled so that the pressure of the nitrogen gas in the reaction vessel 103 becomes approximately 15 atm. When the pressure in the reaction vessel 103 reaches 15 atmospheres, the valve 118 is closed. The above process is performed at a temperature at which the molten Na 122 in the gas supply pipe 104 and the molten Na 712 in the gas supply pipe 701 maintain a liquid state, and a temperature at which substantial evaporation of Na is suppressed (for example, 100 ° C.). Done.
(12) The temperature in the reaction vessel 103 is raised to 800 ° C. by the heaters 109 and 110. Further, the heaters 111, 141 to 143, 703 are energized, the rising portion 104A of the gas supply pipe 104 and the rising portion 701A of the gas supply pipe 701 are heated to the specific temperature Tsp1, and the rising portion 104B of the gas supply pipe 104 is set to the specific temperature. Heat to Tsp2, and the rising portion 701B of the gas supply pipe 701 is heated to the specific temperature Tsp2. When the temperature of the space portion 107 in the reaction vessel 103 reaches 800 ° C., the pressure of the space portion 107 in the reaction vessel 103 becomes 40 atm. At a temperature of 560 ° C. or higher in the temperature raising process, the metal Na and metal Ga in the melt holding container 101 are completely mixed melt.

  At this time, as shown in FIG. 39, the molten Na 122 has two gas-liquid interfaces A and B in the gas supply pipe 104, and the molten Na 712 has two gas-liquid interfaces C in the gas supply pipe 701. , D. Here, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 113 in the gas supply pipe 104 are substantially equal to each other, the level L1 of the gas-liquid interface A and the level L2 of the gas-liquid interface B are almost equal to each other. Match. Further, since the pressure of the space portion 107 in the reaction vessel 103 and the pressure of the space portion 702 in the gas supply pipe 701 are substantially equal to each other, the level L3 of the gas-liquid interface C and the level L4 of the gas-liquid interface D are substantially equal to each other. I'm doing it.

  The vapor pressure PNa1 of the metal Na at the gas-liquid interface A substantially matches the vapor pressure PNa-Ga of the metal Na evaporating from the mixed melt 102, and the vapor pressure PNa3 of the metal Na at the gas-liquid interface C is This substantially coincides with the vapor pressure PNa-Ga of metal Na evaporating from the liquid 102. The vapor pressures PNa1 and PNa3 substantially coincide with the vapor pressure PNa-Ga because the vapor phase transport of the metal Na from the molten Na 122 to the mixed melt 102 is the vapor phase of the metal Na from the mixed melt 102 to the molten Na 122. It is understood that the vapor phase transport of the metallic Na from the molten Na 712 to the mixed melt 102 has reached the equilibrium state with the vapor phase transport of the metallic Na from the mixed melt 102 to the molten Na 712. This means that the reduction of metallic Na from the mixed melt 102 is prevented.

  Further, the vapor pressure PNa2 of metal Na at the gas-liquid interface B and the vapor pressure PNa4 of metal Na at the gas-liquid interface D are maintained at vapor pressures at which the metal Na does not substantially evaporate from the molten Na122 and 712, respectively.

  Therefore, the gas-liquid interface A of the molten Na 122 held in the gas supply pipe 104 and the gas-liquid interface C of the molten Na 712 held in the gas supply pipe 701 prevent reduction of metal Na from the mixed melt 102. The gas-liquid interface B of the molten Na 122 is set to a temperature at which evaporation of the metal Na from the molten Na 122 is substantially suppressed, and the gas-liquid interface D of the molten Na 712 is set to the temperature of the metal Na from the molten Na 712. It is set to a temperature at which evaporation is substantially suppressed.

In the temperature raising process of the reaction vessel 103 and the gas supply pipes 104 and 701, the pressure in the space 107 in the reaction vessel 103, the pressure in the space 113 on the nitrogen cylinder side of the gas supply pipe 104, and the argon cylinder in the gas supply pipe 701 are used. The pressure in the space portion 107 in the reaction vessel 103 is increased to 40 atm while controlling the pressure by the pressure regulator 106 and the pressure regulator 706 so that the pressure in the space 702 on the 705 side is substantially the same.
(13) The temperature in the reaction vessel 103 is kept at 800 ° C., and the pressure in the space 107 in the reaction vessel 103 is kept at 40 atmospheres. Thereby, the GaN crystal which is a group III nitride starts growing in the mixed melt 102 in the melt holding container 101.

  As the GaN crystal grows, nitrogen gas in the space 107 in the reaction vessel 103 serving as the nitrogen source is consumed, and the pressure in the space 107 decreases. As the pressure in the space 107 in the reaction vessel 103 decreases, as shown in FIG. 40 as an example, the differential pressure between the space 113 in the gas supply tube 104 and the space 107 in the reaction vessel 103, and the gas supply tube Due to the differential pressure between the space 702 in the space 701 and the space 107 in the reaction chamber 103, the molten Na 122 and 712 move into the reaction chamber 103. As a result, the gas-liquid interfaces A and C rise, the gas-liquid interface B moves to the vicinity of the boundary between the reaction vessel 103 and the gas supply pipe 104, and the gas-liquid interface D is the boundary between the reaction vessel 103 and the gas supply pipe 701. Move to near. At this time, the nitrogen gas is foamed and rises in the molten Na 122 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 113 in the gas supply pipe 104 and the space 107 in the reaction vessel 103 are continuously connected, and nitrogen gas is supplied to the space 107 in the reaction vessel 103. Further, the argon gas becomes a bubble and rises in the molten Na 712 and reaches the space 107 in the reaction vessel 103. Alternatively, the space 702 in the gas supply pipe 701 and the space 107 in the reaction vessel 103 are continuously connected, and argon gas is supplied to the space 107 in the reaction vessel 103. In this way, from the nitrogen gas cylinder 105 until the pressure in the space 113 in the gas supply pipe 104, the pressure in the space 702 in the gas supply pipe 701, and the pressure in the space 107 in the reaction container 103 are substantially equal to each other. Nitrogen gas is supplied to the space 107 of 103, and argon gas is supplied from the argon gas cylinder 705 to the space 107 of the reaction vessel 103. When the pressure in the space 113 in the gas supply pipe 104, the pressure in the space 702 in the gas supply pipe 701, and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, the level of the gas-liquid interface A and the pressure of the gas-liquid interface B The level, the level of the gas-liquid interface C, and the level of the gas-liquid interface D are substantially equal to each other. In the process of crystal growth, the state shown in FIG. 39 and the state shown in FIG. 40 are repeated, and nitrogen gas and argon gas are supplied to the space 107 in the reaction vessel 103.

  At this time, the temperature of the gas-liquid interface A is set to a specific temperature Tsp1 at which the vapor phase transport of metal Na from the molten Na 122 to the mixed melt 102 is in equilibrium with the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 122. The temperature at the gas-liquid interface C is set at a specific temperature at which the vapor phase transport of metal Na from the molten Na 712 to the mixed melt 102 is in equilibrium with the vapor phase transport of metal Na from the mixed melt 102 to the molten Na 712. It is set to Tsp1. Therefore, the space 107 in the reaction vessel 103 is a mixed atmosphere of Na vapor and nitrogen gas. On the other hand, since the temperature of the gas-liquid interface B is maintained at a temperature at which Na does not substantially evaporate as described above, the Na vapor pressure is small and Na is upstream from the gas-liquid interface B (on the side of the nitrogen cylinder 105). ) Can be ignored. Further, as described above, the temperature of the gas-liquid interface D is also maintained at a temperature at which Na does not substantially evaporate. Therefore, the Na vapor pressure is small, and Na is upstream from the gas-liquid interface D (on the argon cylinder 705 side). ) Can be ignored. Even if the molten Na 122 in the gas supply pipe 104 moves into the reaction vessel 103 and the gas-liquid interface B moves to the vicinity of the reaction vessel 103, Na vapor diffused from the gas-liquid interface B remains in the gas supply pipe 104. Since it adheres to the temperature-controlled region and is liquefied there, it does not affect the introduction of nitrogen gas into the space 107 in the reaction vessel 103.

  In manufacturing apparatus 100L, various GaN crystals are manufactured using the nitrogen gas pressure and crystal growth temperature contained in regions REG1, REG2, and REG3 shown in FIG.

  As described above, according to the tenth embodiment, when the pressure in the space 113 in the gas supply pipe 104 and the pressure in the space 107 in the reaction vessel 103 are substantially equal to each other, both spaces are blocked by the molten Na 122. When the nitrogen pressure in the reaction vessel 103 is reduced, nitrogen gas is introduced into the reaction vessel 103.

  Further, the vapor pressure PNa1 of the metal Na at the gas-liquid interface A on the reaction vessel 103 side of the molten Na 122 held in the gas supply pipe 104 substantially matches the vapor pressure PNa-Ga of the metal Na evaporating from the mixed melt 102. At the same time, the vapor pressure PNa3 of the metallic Na at the gas-liquid interface C on the reaction vessel 103 side of the molten Na712 held in the gas supply pipe 701 is substantially equal to the vapor pressure PNa-Ga of the metallic Na evaporating from the mixed melt 102. Match.

  As a result, while preventing diffusion of metal Na to the outside of the reaction vessel 103, the mixing ratio of metal Na and metal Ga in the mixed melt 102 can be kept substantially constant, and a stable supply of nitrogen raw material can be achieved at the same time. It becomes possible. And the growth of the stable GaN crystal is continued, and a high quality, large size, and homogeneous GaN crystal can be manufactured at low cost. Therefore, it is possible to grow a large group III nitride crystal with higher quality than the conventional flux method.

  The rest is the same as in the first and fifth embodiments.

  According to each of the embodiments described above, a high-performance and low-cost group III nitride semiconductor device that could not be realized in the past, for example, an optical device such as a light emitting diode, a semiconductor laser, and a photodiode, and an electronic device such as a transistor can be realized. Become.

  In each of the above-described embodiments, the case where Na is used as the flux has been described. However, the present invention is not limited to this. For example, alkaline metal Li, Na, K, etc., alkaline earth metal Mg, Ca, Sr, etc. May be used.

  In each of the above embodiments, the case where nitrogen gas is used as the substance containing nitrogen has been described. However, the present invention is not limited to this. For example, a compound containing nitrogen as a constituent element such as sodium azide or ammonia may be used. .

  Moreover, although each said embodiment demonstrated the case where Ga was used as a group III metal, it is not restricted to this, For example, you may use B, Al, In, etc. Although boron (B) is not a metal, it can be applied in the present invention as a group III material constituting BN as a group III nitride.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H, 100J, 100K, 100L Manufacturing apparatus 101 Melt holding container (holding container)
102 Mixed melt (melt)
103 Reaction vessel 104,306 Gas supply pipe (part of piping)
109 Heater (part of heating means)
110 Heater (part of heating means)
111 heater (temperature gradient applying means)
112,122,712 Molten Na (liquid)
301 pressure vessel

Japanese Patent Laid-Open No. 2000-12900 JP 2003-178984 A US Pat. No. 5,868,837 JP 2001-058900 A JP 2001-064097 A JP 2001-64098 A JP 2001-102316 A JP 2001-119103 A JP 2002-128586 A JP 2002-128587 A JP 2002-201100 A JP 2002-326898 A JP 2002-338397 A JP 2003-012400 A Japanese Patent Laid-Open No. 2003-081696 JP 2003-160398 A JP 2003-160399 A JP 2003-238296 A JP 2003-206198 A JP 2003-212696 A JP 2003-286098 A JP 2003-286099 A JP 2003-292400 A Japanese Patent Laid-Open No. 2003-300798 Japanese Patent Laid-Open No. 2003-300799 JP 2003-313098 A JP 2003-313099 A JP 2004-168650 A JP 2004-189590 A JP 2004-231447 A JP 2004-277224 A JP 2004-281670 A JP 2004-281671 A JP 2004-307322 A US Pat. No. 6,592,663 US Pat. No. 6,780,239

Claims (11)

A sealable reaction vessel;
A holding vessel that is contained in the reaction vessel and holds a melt containing a Group III metal and a flux;
A heating means disposed outside the reaction vessel and heating the reaction vessel;
A pipe having a structure capable of holding a liquid state flux inside the reaction vessel while connecting the supply source of the substance containing nitrogen outside the reaction vessel and the reaction vessel;
Heating means for maintaining the flux held in the pipe in a liquid state;
With
The flux in the liquid state held in the pipe is in the direction according to the pressure difference between the pressure in the space in the reaction vessel and the pressure in the space on the supply source side from the flux in the pipe. Move in,
The apparatus for producing a group III nitride crystal, wherein the pipe is brought into a closed state or a released state by the movement of the flux in the pipe.   2. The group III nitride crystal according to claim 1, wherein a gas-liquid interface on the supply source side of the liquid state flux held in the pipe is maintained in the pipe when there is no pressure difference. Manufacturing equipment.   Of the at least two gas-liquid interfaces held by the flux in the liquid state held in the pipe, the temperature of the gas-liquid interface closest to the holding container is the flux in the melt held in the holding container. The apparatus for producing a group III nitride crystal according to claim 2, further comprising another heating means for setting the temperature to prevent the decrease. The reaction vessel has a structure capable of holding the liquid state flux inside,
The apparatus for producing a group III nitride crystal according to claim 1, wherein the liquid flux is held in the pipe and in the reaction vessel. The temperature gradient to suppress substantial vaporization of the flux in a liquid state is retained in the pipe, a temperature gradient imparting means for imparting to the pipe, from claim 1, further comprising according to claim 4 The apparatus for producing a group III nitride crystal according to any one of the above. The substance containing nitrogen is a gas,
The interface flux in a liquid state is retained in the pipe is in contact with gas from the supply source in該配tract, any one of claims 1 to 5, characterized in that less than the inner diameter of the pipe Item III-nitride crystal production apparatus. The apparatus for producing a group III nitride crystal according to claim 6 , further comprising a float that is disposed in the pipe and has a specific gravity smaller than the flux in the liquid state and defines a size of the interface. . An auxiliary pipe connecting the reaction vessel and a gas supply source other than nitrogen outside the reaction vessel ;
Second heating means for maintaining the flux held in the auxiliary pipe in a liquid state;
Further comprising
The flux in the liquid state held in the auxiliary pipe is a pressure difference between the pressure in the space in the reaction vessel and the pressure in the space on the gas supply source side other than the nitrogen in the auxiliary pipe. Move in the auxiliary pipe in the direction according to
The auxiliary pipe has a structure capable of holding the flux in the liquid state inside , and the closed state or the closed state is released by the movement of the flux in the auxiliary pipe.
The apparatus for producing a group III nitride crystal according to any one of claims 1 to 7 , wherein: According to claim 8, wherein the temperature gradient to suppress substantial vaporization of the flux in a liquid state is retained in the auxiliary pipe, the temperature gradient imparting means for imparting to the auxiliary pipe, and further comprising Group III nitride crystal production equipment. Gas other than the nitrogen producing apparatus of a group III nitride crystal according to claim 8 or claim 9, characterized in that an inert gas. 11. The apparatus for producing a group III nitride crystal according to claim 1, wherein the liquid flux is an alkali metal. 11.

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