JP4573713B2 - Single crystal manufacturing method and single crystal manufacturing apparatus - Google Patents

Description

  The present invention relates to a method for producing a metal nitride single crystal containing a Group 3 metal element and a single crystal production apparatus used therefor, and in particular, a single crystal used as a light emitting diode and laser diode growth substrate and a power device substrate. The present invention relates to a manufacturing method and a single crystal manufacturing apparatus.

  Recently, research and development on nitride semiconductor materials containing Group 3 elements such as aluminum (Al), gallium (Ga), and indium (In) has been remarkable, and blue light emitting diodes and ultraviolet light emission using nitride semiconductor materials have been developed. Light emitting devices equipped with diodes are beginning to be marketed. In general, these light emitting diodes are formed on a substrate. For example, a gallium nitride (GaN) blue light emitting diode is formed on a substrate by a metal-organic vapor phase epitaxy (MOVPE) or a halogen system. It is formed by a method such as vapor phase growth (Halide Vapor Phase Epitaxy: HVPE). Currently, a sapphire substrate is mainly used as the growth substrate, but sapphire has a large lattice mismatch with the GaN-based light emitting material of 13.8% and has a large number of misfit dislocations. is there.

  For this reason, in order to achieve higher brightness and longer life of the GaN-based light emitting diode, a substrate material having a smaller lattice mismatch than sapphire is required, and the lattice mismatch with the GaN-based light emitting material is 2 Studies have been made to use an aluminum nitride (AlN) single crystal as a substrate that is as small as .4% and has a thermal conductivity that is one digit higher than that of sapphire.

  As a method for producing this AlN single crystal, for example, a sublimation method in which polycrystalline AlN powder is sublimated and then precipitated at a temperature lower than the sublimation temperature (see Patent Document 1), metal Al is vaporized, and Al gas and nitrogen are deposited. The vaporization method (refer nonpatent literature 1) etc. which precipitates what mixed gas is used. FIG. 6 is a cross-sectional view schematically showing a conventional single crystal manufacturing apparatus using a vaporization method. As shown in FIG. 6, the conventional single crystal manufacturing apparatus 50 has a storage container 52 filled with metal Al 53 disposed in a reaction tank 51 provided with an exhaust hole 56 in the upper part. A substrate 55 is disposed above the substrate. Further, a nitrogen gas inlet 54 is provided in a portion between the storage container 52 and the substrate 55 on the side wall of the reaction tank 51. When the AlN single crystal is produced, the vaporization part 61 and the precipitation part 62 are heated by the heating coils 57 and 58, respectively, and nitrogen gas is introduced into the reaction tank 51 from the nitrogen gas inlet 54. As a result, the metal Al 53 is melted, and the Al melt is vaporized according to the vaporization temperature to generate Al gas. Then, the mixed gas of Al gas and nitrogen gas is transferred to the precipitation portion 62 and reacts on the surface of the substrate 55 to precipitate AlN.

Special table 2003-519064 gazette R. Schlesser, 1 other, “Growth of bulk AlN crystals by vaporization of aluminum in a nitrogen atmosphere”, 2002, Journal of Crystal Growth, No. 234, p. 349-353

  However, the conventional techniques described above have the following problems. That is, when an AlN single crystal is produced by a sublimation method, the AlN raw material powder is sintered and its surface area changes, so that there is a problem that it is difficult to make the sublimation rate constant. Further, when an AlN single crystal is produced by a vaporization method, since nitrogen gas is allowed to flow directly on the Al melt, an AlN film is generated on the surface of the Al melt, and the amount of Al vaporization decreases with time. . For this reason, it is difficult to control the vaporization rate of Al with the conventional vaporization method.

  The present invention has been made in view of such a problem, and a nitride film is not formed on the surface of the raw material melt, and the single crystal manufacturing method and the single crystal manufacturing method can stabilize the vaporization rate of the raw material. An object is to provide an apparatus.

  The method for producing a single crystal according to the first invention of the present application includes a step of vaporizing a Group 3 metal material of the periodic table to generate a Group 3 metal gas, and feeding nitrogen gas to a mixing part of the Group 3 metal gas. A step of introducing the Group 3 metal gas into the mixing portion from a nozzle in a state surrounded by a shield gas, and a metal nitride generated by a reaction between the Group 3 metal gas and the nitrogen gas. And a step of precipitating.

  In the present invention, the introduction of the Group 3 metal gas into the mixing portion in a state surrounded by the shield gas prevents the nitrogen gas and the Group 3 metal material from coming into contact with each other. Formation of a nitride film on the surface can be prevented. In addition, the shielding gas can prevent the group 3 metal gas and the nitrogen gas from mixing at the nozzle tip, so that it is difficult for metal nitride to precipitate at the nozzle tip. As a result, the vaporization rate of the Group 3 metal material can be stabilized.

The method for producing a single crystal according to the second invention of the present application includes a step of generating a Group 3 metal gas by vaporizing a Group 3 metal material of the periodic table, and feeding nitrogen gas to a mixing part of the Group 3 metal gas. A step of transporting the metal gas from the group 3 metal material by carrying the metal gas into a carrier gas, and a nozzle in a state where the group 3 metal gas carried by the carrier gas is surrounded by a shielding gas. To the mixing part, and a step of precipitating metal nitride generated by the reaction of the Group 3 metal gas and the nitrogen gas.

  In the present invention, the Group 3 metal gas is carried by a carrier gas, and the Group 3 metal gas carried by the carrier gas is introduced into the mixing portion in a state surrounded by a shield gas. The group 3 metal material is not in direct contact, and the formation of a nitride film on the surface of the group 3 metal material can be prevented. Further, since the shielding gas can prevent the Group 3 metal gas and the nitrogen gas from being mixed in the vicinity of the nozzle tip, the metal nitride is less likely to be deposited at the nozzle tip. As a result, the vaporization rate of the Group 3 metal material can be stabilized.

  As the shielding gas and / or the carrier gas, a gas inert to the Group 3 metal material and the nitrogen gas, such as argon gas, can be used.

  Moreover, you may mix the said group 3 metal gas and the said nitrogen gas on temperature conditions higher than the said precipitation process. Thereby, precipitation of the metal nitride in a mixing part can be prevented.

The apparatus for producing a single crystal according to the third invention of the present application includes a vaporization unit that vaporizes a group 3 metal material of the periodic table to generate a group 3 metal gas, and a mixing unit that mixes the group 3 metal gas and nitrogen gas A nozzle that introduces the Group 3 metal gas into the mixing unit in a state surrounded by a shield gas, and a precipitation unit that deposits a metal nitride generated by the reaction of the Group 3 metal gas and the nitrogen gas And a heating section that heats the vaporizing section, the mixing section, and the precipitation section.

  In the present invention, a nozzle that introduces the Group 3 metal gas into the mixing portion in the state surrounded by the shield gas is provided to prevent contact between the nitrogen gas and the Group 3 metal material. Formation of a nitride film on the surface of the metal material can be prevented. Moreover, since the group 3 metal gas and the nitrogen gas are prevented from being mixed in the vicinity of the nozzle tip by the shielding gas, the deposition of metal nitride at the nozzle tip can be suppressed. As a result, the vaporization rate of the Group 3 metal material can be stabilized.

  The nozzle is, for example, a double pipe in which an inner pipe and an outer pipe having a larger diameter than the inner pipe are arranged coaxially, and the Group 3 metal gas is passed through the inner pipe, The shield gas may flow between the outer pipe and the outer pipe. Thereby, the effect of preventing the formation of a nitride film on the surface of the group 3 metal material and the precipitation of the metal nitride at the nozzle tip is improved, and the vaporization rate of the group 3 metal material is further stabilized.

The apparatus for producing a single crystal according to the fourth invention of the present application introduces a carrier gas on the group 3 metal material, a vaporization section for generating a group 3 metal gas by vaporizing the group 3 metal material of the periodic table, A carrier gas introduction part for transporting the Group 3 metal gas to the carrier gas and transferring it from the Group 3 metal material, a mixing part for mixing the Group 3 metal gas and nitrogen gas, and the carrier gas carried by the carrier gas A nozzle for introducing the Group 3 metal gas into the mixing portion in a state surrounded by a shielding gas; a deposition portion for depositing a metal nitride generated by the reaction of the Group 3 metal gas and the nitrogen gas; And a heating section for heating the vaporizing section, the mixing section, and the precipitation section.

  In the present invention, an introduction part for introducing a carrier gas onto the Group 3 metal material, and a nozzle for introducing the Group 3 metal gas carried by the carrier gas into the mixing part in a state surrounded by a shield gas. Providing and preventing direct contact between the nitrogen gas and the Group 3 metal material can prevent the formation of a nitride film on the surface of the Group 3 metal material. Moreover, since the group 3 metal gas and the nitrogen gas are prevented from being mixed in the vicinity of the nozzle tip by the shielding gas, the deposition of metal nitride at the nozzle tip can be suppressed. As a result, the vaporization rate of the Group 3 metal material can be stabilized.

  The nozzle is, for example, a double pipe in which an inner pipe and an outer pipe having a larger diameter than the inner pipe are coaxially arranged, and the Group 3 metal gas carried by the carrier gas in the inner pipe The shield gas flows between the inner pipe and the outer pipe. This improves the effect of preventing the formation of a nitride film on the surface of the Group 3 metal material and preventing the precipitation of metal nitride at the nozzle tip, and further stabilizes the vaporization rate of the Group 3 metal material.

  According to the present invention, the raw material is obtained by introducing the group 3 metal gas into the mixing section and / or transporting the group 3 metal gas to the mixing section with the carrier gas being transported to the mixing section while being surrounded by the shielding gas. Since the direct contact between the Group 3 metal material and the nitrogen gas is prevented, formation of a nitride film on the surface of the Group 3 metal material is suppressed, and the vaporization rate of the Group 3 metal material can be stabilized. .

Hereinafter, a method for producing a single crystal according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. A method for producing a single crystal according to the present embodiment includes a nitride containing a Group 3 metal element using a vaporization method in which a Group 3 metal gas such as Al, Ga, In, or the like reacts with a nitrogen gas (hereinafter referred to as nitridation). It is a method for producing a single crystal (referred to as a metal). In order to prevent the nitrogen gas and the raw material melt from coming into direct contact with each other, the present inventors have conducted extensive experimental research to solve the above-described problems. A gas inert to the raw material melt and nitrogen gas (hereinafter referred to as an inert gas) such as argon (Ar), helium (He), neon (Ne), and hydrogen (H ₂ ) is flowed between them. In particular, the present inventors have found that when Ar gas is used as an inert gas, the vaporization rate of the raw material is stabilized and fluctuations in production conditions are suppressed.

  First, a method for producing a single crystal according to the first embodiment of the present invention will be described. In the method for producing a single crystal of the present embodiment, a vaporizing section for vaporizing a Group 3 metal material, a mixing section for mixing a Group 3 metal gas generated in the vaporizing section and nitrogen gas, and a metal nitride generated from these mixed gases The single crystal manufacturing apparatus in which the precipitation part which precipitates is provided in this order is used. Then, a carrier gas composed of an inert gas is supplied to the vaporizing portion, and a Group 3 metal gas that is carriered by the carrier gas is introduced into the mixing portion in a state surrounded by a shielding gas, and then nitrided in the precipitation portion. A single crystal of metal is grown.

  FIG. 1 is a cross-sectional view schematically showing a single crystal manufacturing apparatus used in the method for manufacturing a single crystal of the present embodiment. As shown in FIG. 1, a single crystal manufacturing apparatus 10 used in the present embodiment includes, for example, a cylindrical reaction tank 1, and the reaction tank 1 has a Group 3 metal material from below to above. The vaporizing section 21 for vaporizing, the mixing section 22 for mixing the group 3 metal gas generated in the vaporizing section 21 and nitrogen gas, and the precipitation section 23 for depositing metal nitride from these mixed gases are provided in a line in this order. Yes.

  The vaporization section 21 inside the reaction tank 1 is provided with a cylindrical storage container 2 having an open top, and a group 3 metal material 3 such as metal Al is stored in the storage container 2. A carrier gas inlet 4 for introducing a carrier gas made of an inert gas such as Ar is provided on the side wall of the reaction tank 1 above the storage container 2 in the vaporization section 21. This carrier gas has the effect of transferring the group 3 metal gas to the mixing unit 22 and preventing the formation of a nitride film on the melt surface of the group 3 metal material 3. For this reason, in the single crystal manufacturing apparatus 10, it is preferable to set the position of the carrier gas inlet 4 so that the carrier gas is introduced near the surface of the melt of the Group 3 metal material.

  Further, a double pipe is provided coaxially with the reaction tank 1 between the vaporization section 21 and the mixing section 22 inside the reaction tank 1. In this double tube, the outer tube 6 is arranged above the inner tube 5, and the outer diameters of these double tubes are equal to the inner diameter of the reaction tank 1 at the lower end portions, and the inner diameters are the inner tube 5 and the outer tube. An annular member equal to the inner diameter of 6 is joined. And the outer edge part of the annular member joined to the inner tube 5 and the outer tube 6 is joined to the side wall of the reaction tank 1, and the annular member joined to the inner pipe 5 on the side wall of the reaction tank 1 A shield gas inlet 7 for introducing a shield gas made of an inert gas such as Ar is provided at a portion between the annular member joined to the outer tube 6, and a circle joined to the outer tube 6. A nitrogen gas inlet 8 for introducing nitrogen gas is provided in a portion above the annular member. For this reason, the Group 3 metal gas carried by the carrier gas flows through the inner tube 5, and the shielding gas flows between the inner tube 5 and the outer tube 6, and the outer tube 6 and the inner wall of the reaction tank 1 Nitrogen gas flows between them. Thereby, the Group 3 metal gas carried by the carrier gas is introduced into the mixing unit 22 in a state where the periphery thereof is surrounded by the shield gas.

  In the single crystal manufacturing apparatus 10, since a shielding gas is allowed to flow between the inner tube 5 and the outer tube 6 and the periphery of the group 3 metal gas is surrounded by the shielding gas, inflow of nitrogen gas into the vaporizing section 21 is prevented. In addition, it is possible to prevent metal nitride from being deposited on the upper end portion of the inner tube 5. When metal nitride is deposited on the upper end portion of the inner tube 5, the reaction condition between the group 3 metal gas and the nitrogen gas changes, so that the quality of the metal nitride single crystal produced in the precipitation portion 23 is deteriorated.

  Furthermore, a substrate 9 made of AlN, silicon carbide (SiC) or the like is disposed in the precipitation portion 23 inside the reaction tank 1 so as to face the opening of the storage container 2. An exhaust hole 11 for exhausting the gas inside the reaction tank 1 is provided in the upper part of the reaction tank 1. This exhaust hole 11 is for stabilizing the pressure in the reaction tank 1. For example, if the reaction tank 1 is not sealed and the reaction tank 1 has a sealed structure, the gas pressure in the reaction tank 1 fluctuates. Affects the vaporization rate of Group 3 metal materials. The exhaust hole 11 may be provided on the side wall of the reaction tank 1.

  Furthermore, heating coils 12 to 14 are disposed around the reaction tank 1, and these heating coils 12 to 14 individually heat the vaporizing section 21, the mixing section 22, and the precipitation section 23, respectively. Thus, in the single crystal manufacturing apparatus 10, since the temperature of the vaporization part 21, the mixing part 22, and the precipitation part 23 can be controlled separately, a high quality single crystal can be manufactured efficiently.

  Next, the operation of the single crystal manufacturing apparatus 10 configured as described above, that is, a single crystal manufacturing method using the single crystal manufacturing apparatus 10 will be described. First, a storage container 2 disposed in the reaction tank 1 is filled with a Group 3 metal material 3 such as metal Al. Then, the vaporizing section 21 is heated by operating the heating coil 12, the mixing section 22 is heated by operating the heating coil 13, and the precipitation section 23 is heated by operating the heating coil 14. In this case, when the AlN single crystal is manufactured, the vaporization section 22 is, for example, 2000 ° C., the mixing section 22 is, for example, 2200 ° C., and the precipitation section 23 is, for example, 2100 ° C. At this time, an inert gas such as Ar is supplied from the carrier gas inlet 4 to the vaporizing section 21, an inert gas such as Ar is supplied from the shield gas inlet 7, and nitrogen gas is supplied from the nitrogen gas inlet 8. Each is supplied to the mixing unit 22.

  Thereby, the group 3 metal material 3 in the storage container 2 is melted to form a melt, and further vaporized to generate a group 3 metal gas. This Group 3 metal gas is mixed with a carrier gas made of an inert gas such as Ar, flows through the inner pipe 5 and is transferred to the mixing unit 22. Then, in the mixing unit 22, a single crystal of metal nitride is deposited on the substrate 9 disposed in the deposition unit 23 by being mixed with nitrogen gas.

  In the method for producing a single crystal according to the present embodiment, a carrier gas made of an inert gas is caused to flow on the surface of the melt of the Group 3 metal material 3 as a raw material in the vaporization unit 21, and further, Since the shielding gas flows between the gas and the nitrogen gas, it is possible to prevent the nitrogen gas and the raw material melt from coming into contact with each other. As a result, the formation of a nitride film on the melt surface and the deposition of metal nitride on the tip portions of the inner tube 5 and the outer tube 6 are suppressed, so that the vaporization rate of the Group 3 metal material can be stabilized.

  Further, since the shielding gas is allowed to flow between the group 3 metal gas and the nitrogen gas, and the temperature of the mixing portion 22 is set higher than that of the precipitation portion 23, it is possible to prevent the metal nitride from being precipitated in the mixing portion 22. As a result, the Group 3 metal and nitrogen do not react up to the front of the substrate 9 and exist as a Group 3 metal gas and a nitrogen gas, respectively, and bind to each other on the surface of the substrate 9 which is advantageous for nucleation. A quality single crystal is obtained.

  In the method for producing a single crystal according to the present embodiment, the temperature of the vaporization part 21 is 2000 ° C. and the temperature of the precipitation part 23 is 2100 ° C. However, the present invention is not limited to this, and the vaporization part 21 And the temperature of the precipitation part 23 can be suitably set according to the vapor pressure of a raw material. As described above, in order to prevent the metal nitride from being precipitated in the mixing unit 22, the temperature of the mixing unit 22 is desirably higher than the temperature of the precipitation unit 23.

  In the method for producing a single crystal according to the present embodiment, the single crystal is grown on the substrate 9, but the present invention is not limited to this. For example, the inner wall of the reaction vessel is made of carbon (C), tungsten ( When formed of W), tantalum carbide (TaC), or the like, a single crystal can be directly grown on the reaction vessel. However, when epitaxially growing a single crystal, it is preferably formed on a substrate made of AlN, SiC, or the like.

  Next, a method for manufacturing a single crystal according to the second embodiment of the present invention will be described. In the method for producing a single crystal of the first embodiment described above, both the shielding gas and the carrier gas are introduced into the reaction vessel, but the present invention is not limited to this, and the shielding gas and the carrier are used. By introducing at least one of the gases, the effect of stabilizing the vaporization rate of the Group 3 metal material can be obtained.

  Therefore, in the method for producing a single crystal of the present embodiment, a single crystal of metal nitride is produced by introducing only a shielding gas. FIG. 2 is a cross-sectional view schematically showing a single crystal manufacturing apparatus used in the method for manufacturing a single crystal of the present embodiment. In FIG. 2, the same components as those of the single crystal manufacturing apparatus shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. As shown in FIG. 2, the single crystal manufacturing apparatus 30 used in this embodiment includes, for example, a cylindrical reaction tank 1, and the reaction tank 1 has a Group 3 metal material from below to above. The vaporizing section 21 for vaporizing, the mixing section 22 for mixing the group 3 metal gas generated in the vaporizing section 21 and nitrogen gas, and the precipitation section 23 for depositing metal nitride from these mixed gases are provided in a line in this order. Yes.

  The vaporization section 21 inside the reaction tank 1 is provided with a cylindrical storage container 2 having an open top, and a group 3 metal material 3 such as metal Al is stored in the storage container 2. Further, a double pipe is provided coaxially with the reaction tank 1 between the vaporization section 21 and the mixing section 22 inside the reaction tank 1, and a circle joined to the inner pipe 5 on the side wall of the reaction tank 1. A shield gas inlet 7 for introducing a shield gas made of an inert gas such as Ar is provided at a portion between the annular member and the annular member joined to the outer tube 6. A nitrogen gas inlet 8 for introducing nitrogen gas is provided in a portion above the annular member. Then, the Group 3 metal gas generated in the vaporization section 21 flows through the inner pipe 5, and the shielding gas flows between the inner pipe 5 and the outer pipe 6, and the outer pipe 6 and the inner wall of the reaction tank 1 are connected. Nitrogen gas flows between them. As a result, the Group 3 metal gas is introduced into the mixing unit 22 in a state in which the periphery thereof is surrounded by the shield gas.

  Further, an exhaust hole 11 for exhausting the gas inside the reaction tank 1 is provided in the upper part of the reaction tank 1, and a vaporization part 21, a mixing part 22 and a precipitation part 23 are provided around the reaction tank 1. Heating coils 12 to 14 for individually heating are arranged. A substrate 9 made of AlN, SiC, or the like is disposed in the precipitation portion 23 inside the reaction tank 1 so as to face the opening of the storage container 2.

  Next, the operation of the single crystal manufacturing apparatus 30 configured as described above, that is, a single crystal manufacturing method using the single crystal manufacturing apparatus 30 will be described. First, a storage container 2 disposed in the reaction tank 1 is filled with a Group 3 metal material 3 such as metal Al. Then, the vaporizing section 21 is heated by operating the heating coil 12, the mixing section 22 is heated by operating the heating coil 13, and the precipitation section 23 is heated by operating the heating coil 14. In this case, when the AlN single crystal is manufactured, the vaporization section 22 is, for example, 2000 ° C., the mixing section 22 is, for example, 2200 ° C., and the precipitation section 23 is, for example, 2100 ° C. At this time, an inert gas such as Ar is supplied from the shield gas introduction port 7, and nitrogen gas is supplied from the nitrogen gas introduction port 8 to the mixing unit 22.

  Thereby, the group 3 metal material 3 in the storage container 2 is melted to form a melt, and further vaporized to generate a group 3 metal gas. The Group 3 metal gas flows through the inner pipe 5 and is transferred to the mixing unit 22. Then, in the mixing unit 22, a single crystal of metal nitride is deposited on the substrate 9 disposed in the deposition unit 23 by being mixed with nitrogen gas.

  In the method for producing a single crystal of the present embodiment, since the group 3 metal gas is introduced into the mixing portion in a state surrounded by the shield gas, the inflow of the nitrogen gas into the vaporizing portion 21 is prevented, and the inner tube 5 It is possible to prevent metal nitride from being deposited on the upper end. As a result, the formation of a nitride film on the surface of the group 3 metal material and the deposition of metal nitride on the tip portions of the inner tube 5 and the outer tube 6 are suppressed, so that the vaporization rate of the group 3 metal material can be stabilized. .

  Moreover, since the temperature of the mixing unit 22 is set higher than that of the precipitation unit 23, it is possible to prevent metal nitride from being precipitated in the mixing unit 22. Thereby, since the group 3 metal and nitrogen do not react up to the front of the substrate 9 and both are bonded on the surface of the substrate 9, a high-quality single crystal can be obtained. However, in the manufacturing method of the single crystal of this embodiment, since no carrier gas is introduced, the amount of vaporization of the Group 3 metal material is smaller than that of the manufacturing method of the single crystal of the first embodiment described above, Productivity of metal nitride is reduced.

Next, a method for producing a single crystal according to a reference example of the present invention will be described. In the method for producing a single crystal of the present reference example , only a carrier gas is introduced to produce a metal nitride single crystal. FIG. 3 is a cross-sectional view schematically showing a single crystal production apparatus used in the method for producing a single crystal of this reference example . In FIG. 3, the same components as those of the single crystal manufacturing apparatus shown in FIG. As shown in FIG. 3, the single crystal manufacturing apparatus 40 used in this reference example includes a cylindrical reaction tank 1, for example. The reaction tank 1 has a group 3 metal material from below to above. The vaporizing section 21 for vaporizing, the mixing section 22 for mixing the group 3 metal gas generated in the vaporizing section 21 and the nitrogen gas, and the precipitation section 23 for depositing metal nitride from these mixed gases are provided in a line in this order. Yes.

  The vaporization section 21 inside the reaction tank 1 is provided with a cylindrical storage container 2 having an open top, and a group 3 metal material 3 such as metal Al is stored in the storage container 2. A carrier gas inlet 4 for introducing a carrier gas made of an inert gas such as Ar is provided on the side wall of the reaction tank 1 above the storage container 2 in the vaporization section 21.

  A tube 41 is provided between the vaporizing unit 21 and the mixing unit 22. An annular member having an outer diameter equal to the inner diameter of the reaction vessel 1 and an inner diameter equal to the inner diameter of the tube 41 is joined to the lower end portion of the tube 41, and the outer edge portion of the annular member is attached to the side wall of the reaction vessel 1. It is joined. A nitrogen gas inlet 8 for introducing nitrogen gas is provided in a portion of the side wall of the reaction tank 1 above the annular member joined to the pipe 41. For this reason, the group 3 metal gas carried by the carrier gas flows through the pipe 41, and the nitrogen gas flows between the pipe 41 and the inner wall of the reaction tank 1.

  Furthermore, an exhaust hole 11 for exhausting the gas inside the reaction tank 1 is provided in the upper part of the reaction tank 1. Furthermore, heating coils 12 to 14 for individually heating the vaporization unit 21, the mixing unit 22, and the precipitation unit 23 are disposed around the reaction tank 1. A substrate 9 made of AlN, SiC, or the like is disposed in the precipitation portion 23 inside the reaction tank 1 so as to face the opening of the storage container 2.

  Next, the operation of the single crystal manufacturing apparatus 40 configured as described above, that is, a single crystal manufacturing method using the single crystal manufacturing apparatus 40 will be described. First, a storage container 2 disposed in the reaction tank 1 is filled with a Group 3 metal material 3 such as metal Al. Then, the vaporizing section 21 is heated by operating the heating coil 12, the mixing section 22 is heated by operating the heating coil 13, and the precipitation section 23 is heated by operating the heating coil 14. In this case, when the AlN single crystal is manufactured, the vaporization section 22 is, for example, 2000 ° C., the mixing section 22 is, for example, 2200 ° C., and the precipitation section 23 is, for example, 2100 ° C. At this time, an inert gas such as Ar is supplied from the carrier gas inlet 4 to the vaporizer 21, and nitrogen gas is supplied from the nitrogen gas inlet 8 to the mixer 22.

  Thereby, the group 3 metal material 3 in the storage container 2 is melted to form a melt, and further vaporized to generate a group 3 metal gas. This Group 3 metal gas is mixed with a carrier gas made of an inert gas such as Ar, flows through the pipe 41 and is transferred to the mixing unit 22. Then, in the mixing unit 22, a single crystal of metal nitride is deposited on the substrate 9 disposed in the deposition unit 23 by being mixed with nitrogen gas.

In the method for producing a single crystal of the present reference example , since a carrier gas made of an inert gas is allowed to flow on the surface of the melt of the Group 3 metal material 3 as a raw material in the vaporization section 21, a melt of nitrogen gas and the raw material is used. Can be prevented from contacting. As a result, since the formation of a nitride film on the melt surface is suppressed, the vaporization rate of the Group 3 metal material can be stabilized. In addition, since the temperature of the mixing unit 22 is higher than that of the precipitation unit 23, it is possible to prevent metal nitride from being deposited on the tip of the tube 41.

Hereinafter, the effect of the present invention will be described in comparison with a comparative example that is out of the scope of the present invention. First, as an example of the present invention, an AlN single crystal was produced using the apparatus shown in FIG. The manufacturing conditions at that time are shown in Table 1 below. As shown in Table 1 below, metal Al (500 g) was used as a raw material, and the flow rate of nitrogen gas was 500 standard cm ³ / min (sccm). Further, Ar gas was used as the carrier gas and the shield gas, and the flow rates thereof were 50 standard cm ³ / min (sccm). Furthermore, the vaporization part was set to 2000 ° C., the mixing part was set to 2200 ° C., and the precipitation part was set to 2100 ° C. by resistance heating or high-frequency heating. In addition, the temperature of the mixing part shown in following Table 1 is the temperature of an inner tube | pipe and an outer tube | pipe.

  And the reduction | decrease amount of metal Al was measured after 2 hours, 4 hours, 6 hours, and 8 hours after the synthesis | combination start. The results are shown in Table 2 below. FIG. 4 is a graph showing the relationship between the synthesis time and the Al decrease amount in the method for producing a single crystal of this example, with the horizontal axis representing the synthesis time and the vertical axis representing the metal Al decrease amount.

  As shown in Table 2 and FIG. 4, in this example, the synthesis time and the amount of metal Al decrease were in a proportional relationship, and the Al vaporization rate hardly changed.

  Further, as a comparative example of the present invention, an AlN single crystal was produced under the conditions shown in Table 3 below using a conventional single crystal manufacturing apparatus shown in FIG.

  And the reduction | decrease amount of metal Al was measured 2 hours later, 4 hours later, and 6 hours after the synthesis start. The results are shown in Table 4 below. FIG. 5 is a graph showing the relationship between the synthesis time and the Al reduction amount in the method for producing a single crystal of this comparative example, with the synthesis time on the horizontal axis and the metal Al reduction amount on the vertical axis.

  As shown in Table 4 and FIG. 5, in this comparative example, the synthesis time and the amount of metal Al decrease were not proportional, and the Al vaporization rate decreased as the synthesis time increased. Therefore, when the surface of the metal Al as a raw material was analyzed by X-ray diffraction after the experiment was completed, AlN was formed on the surfaces of all the samples. Therefore, in this comparative example, AlN having a vapor pressure lower than that of Al was generated on the surface of the Al melt, so that it is considered that the Al vaporization rate was reduced.

  A single crystal manufacturing method and a single crystal manufacturing apparatus according to the present invention include a metal nitride single crystal suitable as a growth substrate for light emitting diodes such as blue light emitting diodes and ultraviolet light emitting diodes, a growth substrate for laser diodes, and a substrate for power devices. Can be used when producing.

It is sectional drawing which shows typically the single crystal manufacturing apparatus used with the manufacturing method of the single crystal which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows typically the single crystal manufacturing apparatus used with the manufacturing method of the single crystal which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows typically the single crystal manufacturing apparatus used with the manufacturing method of the single crystal which concerns on the reference example of this invention. It is a graph which shows the relationship between the synthesis time in the manufacturing method of the single crystal of the Example of this invention, and Al reduction amount, taking a synthesis time on a horizontal axis and taking a metal Al reduction amount on a vertical axis | shaft. It is a graph which shows the relationship between the synthesis time in the manufacturing method of the single crystal of the comparative example of this invention, and Al reduction amount, taking a synthesis time on a horizontal axis and taking a metal Al reduction amount on a vertical axis | shaft. It is sectional drawing which shows typically the conventional single crystal manufacturing apparatus using the vaporization method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 51; Reaction tank 2, 52; Storage container 3; Group 3 metal material 4; Carrier gas inlet 5, 6, 41; Pipe 7; Shield gas inlet 8, 54; Nitrogen gas inlet 9, 55; 10, 30, 40, 50; Single crystal production apparatus 11, 56; Exhaust holes 12-14, 57, 58; Heating coil 21, 61; Vaporization section 22; Mixing section 23, 62; Precipitation section 53; Metal Al

Claims (11)

A step of evaporating a group 3 metal material of the periodic table to generate a group 3 metal gas, a step of feeding nitrogen gas to a mixing portion with the group 3 metal gas, and a surrounding of the group 3 metal gas A step of introducing into the mixing portion from the nozzle in a state surrounded by a shielding gas, and a step of precipitating metal nitride generated by the reaction between the Group 3 metal gas and the nitrogen gas. Crystal production method. A step of evaporating a group 3 metal material of the periodic table to generate a group 3 metal gas; a step of supplying nitrogen gas to a mixing part of the group 3 metal gas; and the group 3 metal gas as a carrier gas. Carrying the carrier and transferring from the Group 3 metal material, introducing the Group 3 metal gas carried by the carrier gas from the nozzle into the mixing unit in a state surrounded by a shielding gas, and And a step of precipitating metal nitride produced by the reaction between the Group 3 metal gas and the nitrogen gas. The method for producing a single crystal according to claim 1 or 2 , wherein a gas inert to the Group 3 metal material and the nitrogen gas is used as the shielding gas. The method for producing a single crystal according to claim 3 , wherein the shielding gas is an argon gas. The method for producing a single crystal according to claim 2 , wherein a gas inert to the Group 3 metal material and the nitrogen gas is used as the carrier gas. The method for producing a single crystal according to claim 5 , wherein the carrier gas is an argon gas. The method for producing a single crystal according to any one of claims 1 to 6 , wherein the Group 3 metal gas and the nitrogen gas are mixed under a temperature condition higher than that of the precipitation step. A vaporizing section that vaporizes a Group 3 metal material of the periodic table to generate a Group 3 metal gas, a mixing section that mixes the Group 3 metal gas and nitrogen gas, and a shield gas around the Group 3 metal gas A nozzle to be introduced into the mixing part in a state surrounded by a metal, a precipitation part for precipitating metal nitride generated by the reaction between the group 3 metal gas and the nitrogen gas, the vaporization part, the mixing part and the precipitation part And a heating unit that heats the substrate. The nozzle is a double pipe in which an inner pipe and an outer pipe having a larger diameter than the inner pipe are arranged coaxially, and the Group 3 metal gas flows through the inner pipe, and the inner pipe and the outer pipe 9. The apparatus for producing a single crystal according to claim 8 , wherein the shielding gas flows between the tubes. A vaporizing section that vaporizes a Group 3 metal material of the periodic table to generate a Group 3 metal gas; a carrier gas is introduced onto the Group 3 metal material; A carrier gas introduction part for transferring from the Group 3 metal material, a mixing part for mixing the Group 3 metal gas and nitrogen gas, and the Group 3 metal gas carried by the carrier gas are surrounded by a shielding gas. A nozzle that is introduced into the mixing portion in a heated state, a precipitation portion that precipitates metal nitride generated by the reaction of the Group 3 metal gas and the nitrogen gas, and the vaporization portion, the mixing portion, and the precipitation portion are heated. And an apparatus for producing a single crystal. The nozzle is a double pipe in which an inner pipe and an outer pipe having a larger diameter than the inner pipe are arranged coaxially, and the Group 3 metal gas carried by the carrier gas flows through the inner pipe. The apparatus for producing a single crystal according to claim 10 , wherein the shield gas flows between the inner tube and the outer tube.

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