JP2006062947A - Method and apparatus for growing group iii nitride crystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a large group III nitride crystal by a method and apparatus for growing the group III nitride crystal, in which the generation of clogging at the tip end of a supplying tube for supplying a group III metal can be suppressed. <P>SOLUTION: The method for growing the group III nitride crystal comprises reacting the group III metal and nitrogen in a melt containing an alkali metal. In the method for continuously growing the group III nitride crystal by supplying the group III metal from a vessel accommodating the group III metal 7 into the melt 11, the gas-liquid interface between the group III metal and nitrogen in a supplying member is moved to a site where the temperature is set to be lower than the crystal growth temperature of the group III nitride except a group III metal supply time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a crystal growth method and a crystal growth apparatus for a group III crystal used for a semiconductor light emitting element, a substrate for crystal growth of an electronic device, and the like, and more particularly to a method and an apparatus for obtaining a large crystal.

  In general, when a high-quality semiconductor layer is epitaxially grown on a substrate, the lattice constant and the thermal expansion coefficient of the substrate and the semiconductor layer must be approximately the same. However, there is currently no substrate that satisfies both of the group III nitride semiconductors at the same time.

  Therefore, in the group III nitride, generally, a thick film GaN is formed on a heterogeneous substrate having a lattice constant and a thermal expansion coefficient greatly different from those of a group III nitride semiconductor such as sapphire and GaAs by using a crystal growth technique such as ELO. Growing, and using it as a substrate, a semiconductor laser crystal is produced.

However, a GaN substrate grown using a heterogeneous substrate contains a large number of crystal defects at a dislocation density of about 107 cm ⁻² , which is useful for producing practical high-power laser elements and electronic devices. Is still not of sufficient quality.

  On the other hand, various research institutes have tried to produce a GaN bulk single crystal to produce a high-quality GaN substrate, but only a few millimeters are still available, and it has been put into practical use. It is far from the state.

Conventionally, a GaN crystal growth method using Na as a flux has been shown (for example, see Non-Patent Document 1). In this method, sodium azide (NaN ₃ ) as a flux and metal Ga are used as raw materials, and sealed in a stainless steel reaction vessel (inner dimensions; inner diameter = 7.5 mm, length = 100 mm) in a nitrogen atmosphere, By holding this reaction vessel at a temperature of 600 ° C. to 800 ° C. for 24 to 100 hours, a GaN crystal is grown. This method is characterized in that crystal growth at a relatively low temperature of about 600 ° C. to 800 ° C. is possible, and the internal pressure of the container can be as low as about 100 kg / cm ² at most. The size of the crystals obtained by this method is so small that it is less than 1 mm, which is too small for practical use of the device.

  Further, in order to increase the size of the group III nitride crystal, a method of additionally supplementing the group III metal for crystal growth of the group III nitride crystal is shown (for example, see Patent Document 1). In this method, a growth container containing a flux and a group III metal supply pipe are provided, and the group III metal is additionally supplied to the growth container by its own weight. In this method, by additionally replenishing the Group III metal, it is possible to avoid the depletion of the Group III metal during crystal growth, and to suppress the generation of multinuclei and obtain a large Group III nitride crystal.

  In addition, a method for providing a practical group III nitride crystal without complicating the process, without using an expensive reaction vessel, and without reducing the size of the crystal is shown (for example, patents). Reference 2). In this method, a group III nitride crystal is grown using a seed crystal from a region where a solution containing a group III metal, a flux, and a nitrogen raw material are in contact in a reaction vessel. Is moved to a region where the melt and the nitrogen raw material can come into contact with each other.

Furthermore, a method for producing a high-quality and practical size group III nitride crystal is shown (for example, see Patent Document 3). In this method, the temperature in the crystal growth vessel is raised, GaN in the upper part of the vessel is decomposed into Group III metal (Ga) and nitrogen, passed through the mesh, and then supplied to the Na solution in the lower part of the vessel to react. GaN is regrown.
JP 2003-160398 A JP 2001-064098 A JP 2003-160399 A Chemistry of Materials Vol.9 (1997) p.413-416

However, for example, in the method of Non-Patent Document 1, GaN crystal growth is performed by reacting in a stainless steel reaction vessel using sodium azide (NaN ₃ ) as a flux and metal Ga as raw materials. In this state, when a group III nitride is formed from a mixed melt of a group III metal and sodium azide, a large crystal cannot be obtained because the amount of the group III metal consumed for the raw material is reduced. If a large amount of group III metal is charged to eliminate the depletion of the group III metal raw material, multinuclear growth occurs in the reaction vessel, so that there is also a problem that a crystal size as small as 1 mm is obtained.

In the method of Patent Document 1 in which depletion of group III metal is suppressed and a large crystal can be obtained without occurrence of multinuclear growth, a group III nitride crystal grows on the tip of the supply tube for supplying the group III metal, and the tip of the supply tube It has been found that the problem of clogging occurs. This is because the alkali metal vapor adheres to the Group III metal at the tip of the supply pipe, and N ₂ and the Group III metal react to form Group III nitride, thereby filling the hole at the tip of the supply pipe. When the hole at the tip of the supply pipe is clogged, the supply of the group III metal is stopped, so that crystal growth cannot be performed and a large crystal cannot be obtained.

  The present invention has been made in consideration of the above-described circumstances, and an object thereof is to obtain a large group III nitride crystal by a crystal growth method and a crystal growth apparatus that do not cause clogging of a supply pipe tip for supplying a group III metal. And

  In order to solve the above problems, the invention described in claim 1 is a crystal growth method in which a group III metal and nitrogen are reacted in a melt containing an alkali metal to grow a group III nitride crystal, and III In a method of continuously growing a group III nitride crystal by supplying a group III metal into a melt from a container containing a group metal, the group III in the supply member is supplied except when the group III metal is supplied. A group III nitride crystal growth method is characterized in that a gas-liquid interface between a metal and nitrogen is moved to a place where the temperature is lower than the group III nitride crystal growth temperature.

  The invention according to claim 2 is a crystal growth method for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, and containing the group III metal as a raw material. In the method of continuously growing a group III nitride crystal by supplying a group III metal from a container in the melt containing the alkali metal, the III group metal is supplied except when the group III metal is supplied. A Group III nitride crystal growth method is characterized in that the tip of the Group metal supply member is moved to a location that is lower than the Group III nitride growth temperature.

  The invention according to claim 3 is a crystal growth method for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, and contains the group III metal. In a method of continuously growing a group III nitride crystal by supplying a group III metal from a vessel into a melt, a group III metal at the tip of a supply pipe for supplying a group III metal except when the group III metal is supplied The group III nitride crystal growth method is characterized in that the contact between the alkali metal and nitrogen is cut off.

  The invention according to claim 4 is a crystal growth apparatus for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, and contains the group III metal. In the group III nitride crystal growth apparatus having a structure capable of supplying the group III metal from the container into the melt, the tip of the supply member is placed at a temperature below the crystal growth temperature of the group III nitride except when the group III metal is supplied. The evacuated group III nitride crystal growth apparatus is the main feature.

  The invention according to claim 5 is a crystal growth apparatus for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, from a container containing the group III metal. In a Group III nitride crystal growth apparatus having a structure capable of supplying a Group III metal into the melt, the supply member tip is covered so that the Group III metal and the alkali metal vapor do not come into contact with each other except when the Group III metal is supplied. Group nitride crystal growth equipment is the main feature.

  The invention according to claim 6 is a crystal growth apparatus for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, from a container containing the group III metal. In a group III nitride crystal growth apparatus having a structure capable of supplying a group III metal into a melt, a container for storing a group III metal is a cylinder, a piston and a rod are provided inside the cylinder, and the rod is connected to the piston. Group III nitride crystal growth characterized in that it has a structure in which a piston can be driven by operating a rod from the outside of the pressure vessel to supply Group III metal into the reaction vessel Features the device.

  The invention according to claim 7 is the group III nitride crystal growth apparatus according to claim 4 or claim 5, wherein the tip of the supply member for supplying the group III metal is directed to the mixed melt liquid surface direction in the reaction vessel. The group III nitride crystal growth apparatus is the main feature.

According to the present invention, there is provided a crystal growth method for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, from a container containing a group III metal as a raw material. In the method of continuously growing a group III nitride crystal by supplying a group III metal into the melt containing the alkali metal, the group III metal and nitrogen are mixed except when the group III metal is supplied. According to the Group III nitride crystal growth method, the gas-liquid interface is moved to a place where the temperature is lower than the Group III nitride crystal growth temperature. By adopting a method of moving the liquid interface to a place where the temperature is lower than the growth temperature of the group III nitride, the reaction between the group III metal and N ₂ at the tip of the supply pipe can be suppressed, and clogging of the supply pipe can be eliminated. so It is possible to that III-nitride crystal growth method.

  The first embodiment of the present invention employs a method of moving the gas-liquid interface between the group III metal and nitrogen in the supply pipe to a place where the temperature is lower than the group III nitride growth temperature except when the group III metal is supplied. ing. In order to realize this, the container containing the Group III metal is a cylinder, and a piston and a rod are provided inside the cylinder, and the rod is connected to the piston. By operating, the piston can be driven to supply the Group III metal into the reaction vessel.

  The supply of the Group III metal is, for example, supplying 10 cc of the Group III metal in 500 hours, and the supply amount per hour is as small as 0.02 cc. When the group III metal is in a liquid state, surface tension is generated. As one method for dripping, it operates so that 0.1cc may be supplied every 5 hours.

In other words, the standby time (non-supply time) becomes longer than the supply time, and during that time, alkali metal vapor adheres to the gas-liquid interface between the group III metal and nitrogen, and N ₂ diffuses to cause group III nitride crystal growth. As a result, the hole at the tip of the supply pipe is blocked. Moreover, since the tip of the supply pipe for supplying the Group III metal faces the liquid surface direction of the mixed melt in the reaction vessel, it is easy to drop into the reaction vessel due to the weight of the Group III metal during supply. By moving the gas-liquid interface between the group III metal and nitrogen in the supply pipe to a place below the crystal growth temperature, for example, even if alkali metal vapor enters the supply pipe, crystal growth does not occur. Can be eliminated.

According to the second embodiment of the present invention, the supply pipe tip is moved to a temperature region (about 700 ° C. or less) where the group III nitride does not grow during standby time (non-supply time). are those metal is devised so as not to react with N _2, to realize it, it is to propose a device having a structure capable of moving to a location consisting of supply tube tip below the crystal growth temperature.

The third embodiment of the present invention is devised so that the group III metal at the tip of the supply pipe and the alkali metal vapor or N ₂ do not come into contact except when the group III metal is supplied. Even if the group III metal is at the crystal growth temperature of the group III nitride, the group III nitride does not grow unless it comes into contact with the alkali metal vapor or N ₂ , so that the hole at the tip of the supply pipe is not blocked. What has realized this is an apparatus having a structure in which a lid can be provided at the tip of the supply pipe other than when the group III metal is supplied. By covering the tip of the supply pipe, contact between the group III metal and the alkali metal or N ₂ can be avoided during standby (time during which supply is not performed), so that group III nitride crystal growth does not occur.

This embodiment, as shown in FIG. 1, the supply pipe 4 and N ₂ gas supplied N ₂ gas supply pipe 9 is installed to supply reaction chamber 2 and the group III metal in a pressure vessel 1. The supply pipe 4 for supplying the group III metal is connected to the cylinder 3, and the group III metal 7 is accommodated in the cylinder 3, so that the group III metal 7 can be supplied by pushing the piston 5 with the rod 6. ing. A melt 11 made of an alkali metal and a group III metal is accommodated in the reaction vessel 2 and can be heated by a heater 10. During crystal growth, N ₂ gas is introduced into the pressure-resistant vessel 1, the reaction vessel 2 is heated by a heater, and the group III metal and N ₂ gas are reacted to perform group III nitride crystal growth. At this time, when the group III metal in the reaction vessel 2 is consumed by the reaction with the N ₂ gas, the group III metal is depleted, so that the cylinder 3 containing the group III metal 7 enters the reaction vessel 2 through the supply pipe 4. It has a structure that can be supplied. Moreover, since the front-end | tip of the supply pipe | tube 4 has faced the liquid melt 11 liquid surface direction, it becomes easy to dripping with the own weight of a group III metal.

  In this embodiment, as shown in FIG. 2, the gas-liquid interface between the group III metal and nitrogen in the supply pipe is moved to a place where the temperature is lower than the crystal growth temperature of GaN except when the group III metal is supplied. . In order to move the gas-liquid interface between the group III metal and nitrogen to a place where the temperature is lower than the GaN crystal growth temperature, it is only necessary to operate the rod 6 and pull the piston 5. However, since the position of the gas-liquid interface cannot be determined from the outside of the pressure vessel 1, it is necessary to accurately grasp the inner diameter of the cylinder 3, the hole diameter of the supply pipe 4, and the position of the rod 6 to control the position of the gas-liquid interface. There is.

  In this embodiment, the cylinder 3 has an inner diameter of 20 mm and a length of 40 mm, and the hole diameter of the supply pipe 4 is 1 mm. The distance from the tip of the supply tube 4 to the place where the temperature is below the GaN crystal growth temperature is 100 mm.

To move to the following location GaN crystal growth temperature has to be retracted over 100 mm, from the cylinder 3 the inner diameter area ratio (approximately 314 mm ²⁾ and the supply pipe 4 hole area (approximately 0.78 mm ²⁾ (402-fold) The moving amount of the piston 5 is about 0.25 mm or more. In order to accurately control the piston 5, for example, a mechanism for operating the rod 6 by rotating a screw is provided, and in order to move the piston 5 by 0.25 mm using a screw having a pitch of 3 mm, a 30 ° screw can be rotated. The gas-liquid interface between the group III metal and nitrogen in the supply pipe 4 can be controlled.

  More specifically, the group III metal is Ga, and the alkali metal is Na. Into a reaction vessel 2 made of BN (boron nitride), 3 g of Ga and Na were charged in advance so that the weight ratio was 1: 1 respectively to form a mixed melt 11 and placed in the pressure vessel 1 made of SUS. Install the flange 8 of the container 1. The SUS cylinder 3 is charged with 10 cc of Ga and the supply pipe 4 is inserted through the flange 8 as shown in FIG.

In the GaN crystal growth, N ₂ gas is introduced into the pressure vessel 1 from the N ₂ gas supply pipe 9 so as to be 8 MPa, and heated by the heater 10 so that the temperature becomes 800 ° C. Since Ga and N ₂ react to grow GaN crystals in the reaction vessel 2, the raw material Ga is consumed, so that Ga 7 is supplied into the reaction vessel 2 by operating the rod 6. The crystal growth time is 500 hours, and when Ga is used up within the 10 cc crystal growth time, it becomes 0.02 cc per hour. As described above, at 0.02 cc, 0.1 cc is supplied every 5 hours because it remains at the tip of the supply pipe and cannot be dropped due to the effect of surface tension. When the supply is completed, the rod is operated to move the gas-liquid interface between Ga and nitrogen to a place where the temperature is lower than the growth temperature of the GaN crystal (the portion above AA ′ in FIG. 2), and Ga and N ₂ react. Is prevented.

The present embodiment will be described with reference to FIG. 1. In order to supply the group III metal 7, the tip of the supply pipe 4 is inserted into the reaction vessel 2, and the piston 6 is operated by operating the rod 6 to operate the group III. Metal 7 is supplied into the reaction vessel 2. When the supply is completed, the supply pipe 4 is moved as shown in FIG. 3 so that the tip of the supply pipe 4 comes to a temperature region (above FIG. 3A-A ′) where the group III nitride does not grow. By placing the tip of the supply pipe 4 in a temperature region where the group III nitride does not grow during the standby time (non-supply time), the group III metal at the tip of the supply pipe 4 and the N ₂ gas do not react to eliminate clogging. Can do.

  More specifically, the group III metal is Ga, and the alkali metal is Na. Into a reaction vessel 2 made of BN (boron nitride), 3 g of Ga and Na were charged in advance so that the weight ratio was 1: 1 respectively to form a mixed melt 11 and placed in the pressure vessel 1 made of SUS. Install the flange 8 of the container 1. When 10 cc of Ga is charged in the SUS cylinder 3 and the supply pipe 4 is inserted from the flange 8, the structure shown in FIG. 3 is obtained.

In the GaN crystal growth, N ₂ gas is introduced into the pressure vessel 1 from the N ₂ gas supply pipe 9 so as to be 8 MPa, and heated by the heater 10 so that the temperature becomes 800 ° C. Since Ga and N ₂ react to grow GaN crystals in the reaction vessel 2, the raw material Ga is consumed. Therefore, the supply pipe 4 is moved into the reaction vessel 2, and the operation of the rod 6 causes Ga 7 to be added to the reaction vessel 2. Supply in. The crystal growth time is 500 hours, and when Ga is used up within the 10 cc crystal growth time, it becomes 0.02 cc per hour. As described above, at 0.02 cc, it stays at the tip of the supply pipe due to the effect of surface tension and cannot be dropped, so that 0.1 cc is supplied every 5 hours. When the supply is completed, the tip of the supply tube 4 is moved to a place where the temperature is lower than the growth temperature of the GaN crystal (a portion above AA ′ in FIG. 3), and Ga and N ₂ react at the tip of the supply tube 4. Is preventing.

  In this embodiment, as shown in FIGS. 4 and 5, the cylinder 3 is accommodated in the pressure vessel 1, and the tip of the supply pipe 4 is moved by a cylinder support 12 extending outside the flange 8. The cylinder 3 and the supply pipe 4 are moved simultaneously.

  FIG. 4 is a diagram in which Ga 7 is supplied. The cylinder support 12 is pushed in, the tip of the supply pipe 4 is brought close to the reaction vessel 2, the piston 5 is pushed by operating the rod 6, and Ga is supplied into the reaction vessel 2. Yes. FIG. 5 shows a state during standby (non-supply time). When the supply is completed, the cylinder support 12 is pulled out, and the tip of the supply pipe 4 is temperature range where no Ga nitride crystal grows (from FIG. 5A-A ′). (Upper part).

  By accommodating the cylinder 3 in the pressure vessel 1, projections and the like outside the pressure vessel 1 can be reduced, and the external dimensions of the apparatus can be reduced.

In this embodiment, as shown in FIG. 6, a lid 14 is formed at the tip of the supply pipe 4, and can be opened and closed by an opening / closing bar 13 that operates the lid 14. The lid 14 and the open / close bar 13 are made of SUS, and the contact of Na vapor or N ₂ with the gas can be reduced by making the lid 14 have a protruding shape as shown in FIG. The lid 14 has a structure that can be opened and closed by the operation of the opening / closing bar 13 at the tip of a bar 15 fixed to the tip of the supply pipe 4. Here, when the opening / closing bar 13 is pushed from the outside of the flange 8, the lid at the tip of the supply pipe 4 is closed as shown in FIG. 7A, and when the opening / closing bar 13 is pulled from the outside of the flange 8, it is shown in FIG. In this way, the lid 14 at the tip of the supply pipe 4 is open.

  During standby (non-supply time), in FIG. 7A, the lid 14 is pushed to the tip of the supply pipe 4 by pushing the open / close bar 13, and the lid 14 is pulled out of the supply pipe 4 by pulling the open / close bar 13 during supply. The piston 5 is moved by operating the rod 6 away from the tip, and Ga 7 is supplied to the reaction vessel 2.

Although this lid 14 cannot completely cut off contact with Na vapor or N ₂ gas, clogging of the tip of the supply pipe 4 does not occur due to repeated opening and closing of the lid 14 by supply every 5 hours.

  The container for containing the group III metal 7 has a structure as shown in FIG. 8, the cylinder 3 for containing the group III metal 7 and the rod 6 connected to the piston 5 are installed outside the pressure vessel, and the supply pipe 4 is flanged. 8 is inserted into the reaction vessel. The cylinder 3, the piston 5 and the rod 6 are made of stainless steel, and a packing (not shown) is attached to the piston 5 so that the group III metal 7 does not leak.

  The supply pipe 4 is attached to the flange 8 by packing (not shown), and the group III metal 7 in the cylinder 3 can be supplied into the reaction vessel 2 by moving the rod 6 up and down.

  The supply pipe 4 is made of stainless steel at a portion to be inserted into the pressure resistant container 1, but is connected to a supply pipe made of BN (boron nitride) by a connection pipe 17 in the reaction container 2. In this embodiment, Ga is used as the group III metal material. However, since Ga reacts with Fe at about 400 ° C. or higher and forms an alloy, it does not react with Ga at the portion exposed to the high temperature (800 ° C.) at the tip. A supply pipe 16 made of BN is used.

  In this embodiment, the cylinder 3 has an inner diameter of 20 mm and a length of 40 mm, the supply pipe 4 is a 1/4 inch pipe, the BN supply pipe 16 has an outer diameter of 1/4 inch and an inner diameter of 1 mm.

At the time of supply of group III nitride crystal growth, the rod 6 is pushed in to supply the group III metal 7 into the reaction vessel 2, and at the time of standby (non-supply time), the rod 6 is pulled so that the group III metal 7 and nitrogen gas are supplied. Is moved to a temperature region where Ga and N ₂ do not react.

According to the method of claim 2, when supplying, the cylinder 3 is lowered and the supply tube tip 16 is inserted into the reaction vessel, the rod 6 is pushed to supply the group III metal 7 into the reaction vessel 2, In the (non-supply time), the clogging of the supply pipe tip can be prevented by raising the cylinder 3 and moving the supply pipe tip to a temperature region where Ga and N ₂ do not react.

It is sectional drawing of the reactor which grows the group III nitride crystal of this invention. It is sectional drawing of the reaction apparatus except the time of supply of the group III metal of this invention. It is explanatory drawing of group III metal supply apparatus movement in the crystal growth reaction of this invention. It is sectional drawing of the other reactor which grows the nitride crystal of this invention. It is explanatory drawing of the other supply apparatus movement by the crystal growth reaction of this invention. It is sectional explanatory drawing of the metal supply apparatus with a lid | cover of the crystal growth apparatus of this invention. It is explanatory drawing of the lid | cover operation mechanism of the supply apparatus with a lid | cover of the growth apparatus of this invention. It is an enlarged view which shows the container which accommodates the group III metal of this invention.

Explanation of symbols

1 pressure-resistant container 2 reactor 3 cylinders 4,16 supply pipe 5 the piston 6 rod 7 III metals 8 flange 9 N ₂ gas feed pipe 10 Heater 11 melt 12 cylinder support 13 closing bars 14 cover 15 bar 17 connecting pipe

Claims (7)

A crystal growth method for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, wherein the group III metal is contained in the melt from a container containing the group III metal. In the method of continuously growing the group III nitride crystal by supplying to
The group III nitride is characterized in that the gas-liquid interface between the group III metal and nitrogen in the supply member is moved to a place below the crystal growth temperature of the group III nitride except when the group III metal is supplied. Crystal growth method. A crystal growth method for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, wherein the group III metal is introduced into the alkali from a container containing the group III metal as a raw material. In a method for continuously growing a group III nitride crystal by supplying it into a melt containing a metal,
A Group III nitride crystal growth method, wherein the tip of the Group III metal supply member is moved to a place where the temperature is lower than the Group III nitride growth temperature except when the Group III metal is supplied. A crystal growth method for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, wherein the group III metal is contained in the melt from a container containing the group III metal. In the method of continuously growing the group III nitride crystal by supplying to
A Group III nitride crystal growth method characterized in that contact between the Group III metal, alkali metal and nitrogen at the tip of a supply pipe for supplying a Group III metal is interrupted except when the Group III metal is supplied. A crystal growth apparatus for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, and the group III metal from a container containing the group III metal in the melt In a group III nitride crystal growth apparatus having a structure that can be supplied to
The group III nitride crystal growth apparatus characterized in that the tip of the supply member is retracted to a place where the temperature is lower than the group III nitride crystal growth temperature except when the group III metal is supplied. A crystal growth apparatus for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, and the group III metal from a container containing the group III metal in the melt In a group III nitride crystal growth apparatus having a structure that can be supplied to
A III-nitride crystal growth apparatus characterized in that the tip of the supply member is covered so that the group III metal and the alkali metal vapor are not brought into contact except during the supply of the group III metal.   A crystal growth apparatus for growing a group III nitride crystal by reacting a group III metal and nitrogen in a melt containing an alkali metal, and the group III metal from a container containing the group III metal in the melt In a group III nitride crystal growth apparatus having a structure that can be supplied to a cylinder, a container for storing a group III metal is a cylinder, a piston and a rod are provided inside the cylinder, and the rod is connected to the piston. A group III nitride crystal growth apparatus characterized by having a structure in which a piston can be driven by operating a rod from the outside of a pressure vessel to supply a group III metal into the reaction vessel.   The group III nitride crystal growth apparatus according to claim 4 or 5, wherein a tip of a supply member for supplying the group III metal faces a mixed melt liquid surface direction in a reaction vessel.

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