Iii-group compound semiconductor crystal manufacturing device

Abstract

To provide a III-group compound semiconductor crystal manufacturing device that can suppress adhesion of deposits to the inner wall surface of a reaction vessel during III-group compound semiconductor crystal growth.SOLUTION: A III-group compound semiconductor crystal manufacturing device according to the present disclosure includes a substrate holding member for holding a seed substrate, and a gas flow channel forming a gas flow path through which gas flows toward the substrate holding member, and the gas flow channel includes a connection portion whose downstream inner diameter is larger than its upstream inner diameter, and the upper surface of the substrate holding member is positioned within the connection portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a manufacturing apparatus for Group III compound semiconductor crystals, and more particularly to a manufacturing apparatus for Group III compound semiconductor crystals by vapor phase growth, in which gas is supplied to a substrate to be processed placed in a reaction chamber. [Background technology]

[0002] Group III compound semiconductors such as GaN, AlGaN, InGaN, and Ga2O3 are used in fields such as optical devices such as light-emitting diodes and semiconductor lasers, and heterojunction high-speed electronic devices. One method for producing GaN, a Group III compound semiconductor, is a practical hydride vapor phase epitaxy (HVPE) method in which a Group III element metal (e.g., Ga metal) is reacted with a chloride gas (e.g., HCl gas) to generate a Group III element metal chloride gas (GaCl gas), and GaN is grown from the Group III element metal chloride and a nitrogen-containing gas (e.g., NH3 gas) (see, for example, Patent Document 1).

[0003] However, the HVPE method generates a large amount of NH4Cl (ammonium chloride) as a by-product during crystal growth, which clogs the exhaust piping of the manufacturing equipment and inhibits crystal growth. To solve this problem, oxygen vapor phase epitaxy (OVPE) has been proposed, in which a group III element metal (e.g., Ga metal) is reacted with an oxidizing agent (e.g., HO gas) to generate a group III element metal oxide gas (Ga2O gas), and GaN is grown from the group III element metal oxide gas and a nitrogen-containing gas (e.g., NH3 gas) (see, for example, Patent Document 2).

[0004] A feature of the HVPE and OVPE methods is that they can achieve extremely high growth rates of 10 μm / h or more, or even 100 μm / h or more, compared to the typical growth rate of around 1 μm / h in other crystal growth methods such as metalorganic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE).For this reason, they are used to manufacture freestanding GaN substrates.

[0005] FIG. 6 is a schematic cross-sectional view showing a typical cross-sectional structure of an OVPE apparatus, which is one of conventional Group III compound semiconductor crystal manufacturing apparatuses. This OVPE apparatus includes a reaction vessel 101 for growing compound semiconductor crystals, which includes a source material reaction chamber 102 for generating a Group III element gas such as GaO. The source material reaction chamber 102 is heated by a first heater 104, and a metal source material 106 containing Ga, In, Al, etc. is contained in a source material container 103. A reactive gas supply pipe 107 for supplying a reactive gas such as HO gas is connected to the source material reaction chamber 102. The reactive gas supplied from the reactive gas supply pipe 107 to the source material container 103 reacts with the metal source material 106 to generate a Group III element-containing gas in the source material reaction chamber 102. The generated Group III element-containing gas is introduced into the reaction vessel 101 through a Group III element-containing gas supply pipe 108 connected to the source material reaction chamber 102 and transported to a seed substrate 112 placed on a substrate support 113. Seed substrate 112 is heated by second heater 105. Furthermore, reaction vessel 101 is provided with nitrogen-containing gas supply pipes 109a and 109b for supplying a nitrogen-containing gas such as NH gas. The group III element-containing gas and the nitrogen-containing gas transported to seed substrate 112 react with each other, causing group III nitride semiconductor crystal 111 to grow on seed substrate 112. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 52-23600 [Patent Document 2] WO2015 / 053341 Summary of the Invention [Problem to be solved by the invention]

[0007] However, as shown in FIG. 6 , the source gas injected from the group III element-containing gas supply pipe 108 and the nitrogen element-containing gas supply pipes 109a and 109b is supplied over an area wider than the area of ​​the substrate support 113, typically over the entire reaction chamber 101. This reduces the utilization efficiency of the source gas transported to the seed substrate 112. Furthermore, the source gas that is not transported to the seed substrate 112 reacts with the source gas, and deposits of the generated group III compound semiconductor crystal adhere to the inner wall surface of the reaction vessel 101 and the inside of the exhaust pipe. If particles generated from these deposits are mixed into the group III compound semiconductor crystal on the seed substrate 112, dislocations that impede device operation may be concentrated at a high density, potentially causing defects on the order of micrometers to millimeters, such as regions called pits or through-holes. These defects pose a problem of reducing the yield of semiconductor devices.

[0008] The object of the present invention is to solve the above problems and to provide a Group III compound semiconductor crystal manufacturing apparatus that can suppress adhesion of deposits to the inner wall surface of a reaction vessel and improve the manufacturing yield. [Means for solving the problem]

[0009] In order to achieve the above object, the present disclosure provides a manufacturing apparatus for a Group III compound semiconductor crystal, the manufacturing apparatus for a Group III compound semiconductor crystal comprising a reaction vessel, the reaction vessel having a raw material reaction section, a crystal growth section, and a gas flow channel, the raw material reaction section including a raw material reaction chamber for generating a Group III element-containing gas, and a raw material gas nozzle for directing the generated Group III element-containing gas from the raw material reaction chamber and injecting it toward the crystal growth section, the crystal growth section including a substrate holding member for holding and rotating a seed substrate on an upper surface thereof on which a Group III compound semiconductor crystal is to be grown, and a reactive gas nozzle for injecting a reactive gas toward the seed substrate for reacting with the Group III element-containing gas to generate a Group III compound semiconductor crystal, The row channel includes a first flow channel arranged to surround the nozzle of the raw material gas nozzle and the nozzle of the reactive gas nozzle, a second flow channel, and a connecting part, the first flow channel having a first opening, the second flow channel having a second opening, the area of ​​the second opening being larger than the area of ​​the first opening, the connecting part connecting the first opening and the second opening, the gas flow channel forming a gas flow path through which gas ejected from the raw material gas nozzle and the reactive gas nozzle flows within the reaction vessel by passing through the first flow channel, the connecting part, and the second flow channel in that order, and the substrate holding member is arranged inside the gas flow path and downstream of the first opening. [Effects of the Invention]

[0010] The Group III compound semiconductor crystal manufacturing apparatus of the present disclosure can suppress the generation of deposits on the inner wall surfaces of the apparatus upstream of the seed substrate and suppress the incorporation of particles into the Group III compound semiconductor crystal growing on the seed substrate, thereby improving the yield of Group III compound semiconductor crystal manufacturing. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing an example of the configuration of a Group III compound semiconductor crystal manufacturing apparatus according to an embodiment of the present disclosure. [Figure 2]2A and 2B are a front cross-sectional view and a top view showing an example of the arrangement of a source gas nozzle and a reactive gas nozzle in the Group III compound semiconductor crystal manufacturing apparatus of FIG. 1; [Figure 3] FIG. 2 is a schematic cross-sectional view showing the configuration of a Group III compound semiconductor crystal manufacturing apparatus according to Comparative Example 1 of the present disclosure. [Figure 4] 1 is a schematic cross-sectional view showing the configuration of a Group III compound semiconductor crystal manufacturing apparatus according to Reference Example 1 of the present disclosure. [Figure 5] 1A is a photograph showing the appearance of a GaN substrate grown on a seed substrate according to Example 1 of the present disclosure, and FIG. 1B is a photograph showing the appearance of a GaN substrate grown on a seed substrate according to Comparative Example 1. [Figure 6] 1 is a schematic cross-sectional view showing a typical cross-sectional structure of an OVPE apparatus, which is one of conventional apparatuses for producing Group III compound semiconductor crystals. DETAILED DESCRIPTION OF THE INVENTION

[0012] According to a first aspect of the present invention, there is provided an apparatus for manufacturing a Group III compound semiconductor crystal, comprising a reaction vessel, the reaction vessel having a raw material reaction section, a crystal growth section, and a gas flow channel, the raw material reaction section including a raw material reaction chamber for generating a Group III element-containing gas, and a raw material gas nozzle for leading the generated Group III element-containing gas from the raw material reaction chamber and injecting it toward the crystal growth section, the crystal growth section including a substrate holding member for holding and rotating a seed substrate on an upper surface on which a Group III compound semiconductor crystal is to be grown, and a reactive gas nozzle for injecting a reactive gas toward the seed substrate for reacting with the Group III element-containing gas to generate a Group III compound semiconductor crystal, the gas flow channel including an injection port of the raw material gas nozzle and a reaction gas nozzle. a first flow channel arranged to surround an outlet of a reactive gas nozzle, a second flow channel, and a connecting part, the first flow channel having a first opening, the second flow channel having a second opening, the area of ​​the second opening being larger than that of the first opening, the connecting part connecting the first opening and the second opening, the gas flow channel forming a gas flow path through which gases ejected from the source gas nozzle and the reactive gas nozzle flow inside the reaction vessel by passing through the first flow channel, the connecting part, and the second flow channel in this order, and the substrate holding member is arranged inside the gas flow path and downstream of the first opening.

[0013] According to a second aspect of the present invention, there is provided the apparatus for manufacturing a Group III compound semiconductor crystal according to the first aspect, wherein the connection portion is configured in a tapered shape that widens from the first opening toward the second opening.

[0014] According to a third aspect of the present invention, there is provided the apparatus for manufacturing a Group III compound semiconductor crystal according to the first or second aspect, wherein the substrate holding member is disposed downstream of the second opening.

[0015] According to a fourth aspect of the present invention, there is provided the apparatus for manufacturing a Group III compound semiconductor crystal according to any one of the first to third aspects, wherein the difference between the area of ​​the first opening and the area of ​​the upper surface of the substrate holding member is within 30% of the area of ​​the upper surface of the substrate holding member.

[0016] According to a fifth aspect of the present invention, there is provided the apparatus for manufacturing a Group III compound semiconductor crystal according to any one of the first to fourth aspects, wherein the difference between the area of ​​the first opening and the area of ​​the second opening minus the area of ​​the upper surface of the substrate holding member is within 50% of the area of ​​the first opening.

[0017] According to a sixth aspect of the present invention, there is provided the apparatus for producing a Group III compound semiconductor crystal according to any one of the first to fifth aspects, wherein the first flow channel and the second flow channel are configured to have a cylindrical shape, and the difference between the vertical distance from the source gas nozzle to the upper surface of the substrate holding member and the vertical distance from the outlet of the source gas nozzle to the second opening is within 30% of the vertical distance from the source gas nozzle to the upper surface of the substrate holding member.

[0018] According to a seventh aspect of the present invention, there is provided the apparatus for producing a Group III compound semiconductor crystal according to any one of the first to sixth aspects, wherein the source gas nozzle is arranged so that the injection direction of the injection port faces the upper surface of the substrate holding member.

[0019] According to an eighth aspect of the present invention, there is provided the apparatus for manufacturing a Group III compound semiconductor crystal according to any one of the first to seventh aspects, wherein the reactive gas nozzle is arranged so that the ejection direction of the ejection port is inclined with respect to the upper surface of the substrate holding member.

[0020] According to a ninth aspect of the present invention, there is provided the apparatus for producing a Group III compound semiconductor crystal according to any one of the first to eighth aspects, wherein the reactive gas nozzle is arranged so that the injection direction of the injection port on the upper surface of the substrate holding member is deflected with respect to the radial direction of rotation of the seed substrate.

[0021] Hereinafter, a manufacturing apparatus for a group III compound semiconductor crystal according to an embodiment of the present disclosure will be described with reference to the drawings, in which substantially identical components are designated by the same reference numerals.

[0022] (Embodiment) <Manufacturing Apparatus for Group III Compound Semiconductor Crystal> Hereinafter, embodiments of the present disclosure will be described with reference to FIG. 1.

[0023] FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a manufacturing apparatus 1 for a group III compound semiconductor crystal according to an embodiment of the present disclosure. Note that in FIG. 1, the sizes, ratios, etc. of each constituent member may be different from the actual ones.

[0024] The manufacturing apparatus 1 for a group III compound semiconductor crystal according to the present embodiment shown in FIG. 1 is a vapor phase growth apparatus and includes a reaction vessel 20 for crystal growth of a group III compound semiconductor. The reaction vessel 20 may have, for example, a cylindrical shape, and has a raw material reaction section 5 that generates a group III element-containing gas, a crystal growth section 6, and a gas flow channel 10. In a raw material reaction chamber 3 provided in the raw material reaction section 5, a group III element-containing gas is generated. The generated group III element-containing gas is导出 by a raw material gas nozzle 8 and喷射 toward the crystal growth section 6. In the crystal growth section 6, the group III element-containing gas ejected by the raw material gas nozzle 8 and the reactive gas introduced by a reactive gas nozzle 9 are混合 in a mixing region S1 and then react in a crystal growth region S2 on the seed substrate 11, whereby a group III compound semiconductor crystal grows on the seed substrate 11.

[0025] In order to maintain a constant temperature in the raw material reaction section 5 and the crystal growth section 6, a heating section 16 is installed on the outer peripheral portion of the reaction vessel 20. Further, the raw material gases of the unreacted group III element-containing gas and the reactive gas, and carrier gases such as H2 and N2 are排出 from an exhaust port 17 provided on the downstream side of the seed substrate 11.

[0026] According to the manufacturing apparatus 1 for a group III compound semiconductor crystal according to the embodiment, it is possible to suppress the generation of deposits on the inner wall surface of the apparatus on the upstream side of the seed substrate 11 and suppress the contamination of particles into the group III compound semiconductor crystal growing on the seed substrate.

[0027] The components of the Group III compound semiconductor crystal manufacturing apparatus 1 according to the embodiment shown in FIG. 1 will be described in detail below.

[0028] <Raw material reaction section> The raw material reaction section 5 includes a raw material reaction chamber 2 and a raw material gas nozzle, and has a cylindrical shape in this embodiment. In the raw material reaction section 5, a group III element-containing gas is generated.

[0029] (raw material reaction chamber) A source vessel 3 containing a starting Ga source 4, which is a Group III element-containing source, is disposed within the source reaction chamber 2. The source reaction chamber 2 is also connected to a reactive gas supply pipe 7, through which a reactive gas that reacts with the starting Ga source 4 is introduced. The interior of the source reaction chamber 2 is maintained at a desired temperature by a first heater 14 of a heating unit 16. Preferably, the starting Ga source 4 reacts with the reactive gas in the source reaction chamber 2, which is maintained at a temperature of 900°C or higher and 1300°C or lower by heating with the first heater 14, to generate a Group III element-containing gas.

[0030] Here, methods for generating a group III element-containing gas include a method of oxidizing a group III element-containing source and a method of reducing a group III element-containing source.

[0031] As a method for oxidizing a group III element-containing source, a reaction system will be described in which metallic Ga is used as the starting Ga source 4 and HO gas, an oxidizing gas, is used as the reactive gas. In this case, as shown in the following formula (1), the introduced HO gas reacts with metallic Ga under heating to generate GaO gas, a group III element-containing gas.

[0032] [C1] 2Ga+H2O → Ga2O+H2(1)

[0033] In addition to Ga, Al, In, etc. can also be used as the group III element source. In either case, a group III oxide gas is generated.

[0034] Next, a reaction system will be described for a method of reducing a Group III element-containing source, in which Ga2O3 is used as the starting Ga source 4 and H2 gas, a reducing gas, is used as the reactive gas. As shown in the following formula (2), when heated, introduced H2 gas reacts with Ga2O3 to generate Ga2O gas, a Group III element-containing gas.

[0035] [C2] Ga2O3+2H2→Ga2O+2H2O (2)

[0036] In addition to Ga2O3, Al2O3, In2O3, etc. can also be used as the group III element source. In either case, a group III oxide gas is generated.

[0037] As a carrier gas for the oxidizing gas or reducing gas, an inert gas such as Ar or N2, or H2 gas can be used.

[0038] (raw material gas nozzle) The Group III element-containing gas, e.g., GaO gas, generated in the raw material reaction chamber 2 is directed through a raw material gas nozzle 8 located downstream of the raw material reaction section 5 and sprayed toward the crystal growth section 6. To prevent deposits of Group III compound semiconductor crystals from adhering to the inner wall surfaces of the manufacturing apparatus 1, the raw material gas nozzle 8 preferably has a separator gas outlet formed on its inner or outer periphery. The separator gas may be, but is not limited to, an inert gas such as Ar or N2, or H2 gas. The inner diameter of the raw material gas nozzle 8 is preferably, but is not limited to, a range of more than 0 mm and not more than 100 mm, more preferably 20 mm to 60 mm. The wall thickness of the raw material gas nozzle 8 is also not limited to, but is preferably 0.5 mm to 10 mm, more preferably 1 mm to 3 mm.

[0039] <Crystal growth section> The crystal growth section 6 has a cylindrical shape in this embodiment and includes a substrate holding member 12 and a reactive gas nozzle 9. In the crystal growth section 6, the Group III element-containing gas reacts with a reactive gas (such as a nitrogen-containing gas or an oxygen-containing gas), and a Group III compound semiconductor crystal grows on the seed substrate.

[0040] (Substrate holding member) The substrate holding member 12 may be, for example, a substrate susceptor. The seed substrate 11 is held on the upper surface 12a of the substrate holding member 12. The shape of the substrate holding member 12 is not particularly limited, but it is preferable that the substrate holding member 12 does not have a structure that inhibits crystal growth. For example, if a structure that may allow crystal growth exists near the crystal growth surface of the seed substrate 11, a circulating flow will be generated, and deposits will adhere to the structure, thereby deteriorating the uniformity of the Group III compound semiconductor crystal film on the seed substrate 11. In this embodiment, the seed substrate 11 and the substrate holding member 12 are circular. The substrate holding member 12 can be made of a material such as ceramics, such as carbon, SiC-coated carbon, PG-coated carbon, PBN-coated carbon, or SiC; molybdenum, iron, cobalt, nickel; or an alloy containing any of these as its main components.

[0041] Furthermore, substrate holding member 12 is connected to rotating shaft 13, which allows substrate holding member 12 to rotate seed substrate 11 during Group III compound semiconductor crystal growth. Rotating shaft 13 preferably has a mechanism capable of controlling rotation up to 3000 rpm.

[0042] (reactive gas nozzle) The reactive gas nozzle 9 injects a reactive gas (such as a nitrogen-containing gas or an oxygen-containing gas) toward the seed substrate 11 to react with the group III element-containing gas to produce a group III compound semiconductor crystal. In the group III compound semiconductor crystal manufacturing apparatus 1 shown in FIG. 1 , at least two reactive gas nozzles 9 are provided, and the two or more reactive gas nozzles 9 may be arranged, for example, radially with respect to the center of the substrate holding member 12, although this arrangement is not particularly limited. In order to improve the mixing efficiency of the group III element-containing gas injected from the source gas nozzle 8 and the reactive gas injected from the reactive gas nozzle 9, the injection direction of the reactive gas nozzle 9 preferably intersects with the injection direction of the source gas nozzle 8 just before the upstream side of the seed substrate 11, when viewed from the front and from above with respect to the upper surface 12 a of the substrate holding member 12.

[0043] 2A and 2B are a front cross-sectional view and a top view, respectively, showing an example of the arrangement of the source gas nozzle and the reactive gas nozzle in the Group III compound semiconductor crystal manufacturing apparatus 1 of FIG. 1. As shown in FIG. 2A, the source gas nozzle 8 is arranged along a linear direction D, with the ejection direction of its ejection port facing the upper surface 12a of the substrate holding member. The reactive gas nozzle 9 includes a main body 21 and a tip portion 23 having an ejection port 22. The tip portion 23 is inclined at an inclination angle θa with respect to the direction D. That is, in the front view of FIG. 2A, an imaginary line 24 extending along the ejection direction of the reactive gas nozzle 9 and an imaginary line 25 extending along the ejection direction of the source gas nozzle 8 intersect at a position F above the substrate holding member 12. The inclination angle θa is the angle between the ejection directions of the source gas nozzle 8 and the reactive gas nozzle 9 in a plane perpendicular to the upper surface 12a of the substrate holding member.

[0044] Next, as shown in FIG. 2(b), the manufacturing apparatus 1 for producing a Group III compound semiconductor crystal includes at least two reactive gas nozzles 9. In this embodiment, the at least two reactive gas nozzles 9 are arranged radially about the center of the substrate holding member 12, as shown in the top view of FIG. 2(b). The tip 23 of the reactive gas nozzle 9 is inclined at a deflection angle θb with respect to the radial direction E on the top surface 12a of the substrate holding member. That is, the deflection angle θb is the angle formed between the tip 23 of the reactive gas nozzle 9 and the radial direction of the seed substrate 11, as seen in the top view of FIG. 2(b).

[0045] In this embodiment, each reactive gas nozzle 9 is arranged so that when it self-rotates at a deflection angle θb in the forward direction of the rotation direction A of the substrate holding member 12 as viewed from above in FIG. 2(b), it is aligned in the radial direction of the upper surface 12a of the substrate holding member. This allows the reactive gas ejected from the multiple reactive gas nozzles 9 to form a swirling flow, which can improve the mixing efficiency with the group III element-containing gas. Note that the ejection direction of the multiple reactive gas nozzles 9 is not limited to this, and the ejection direction may be deflected in the opposite direction to that shown in FIG. 2(b).

[0046] In the crystal growth section 6, a group III compound semiconductor crystal, such as GaN or Ga2O3, can be grown on the seed substrate 11. When growing a GaN crystal, a nitrogen-containing gas, such as NH3 gas, NO gas, NO2 gas, N2H2 gas, or N2H4 gas, can be used. When growing a Ga2O3 crystal, an oxygen-containing gas, such as O2 gas or HO gas, can be used. Similarly to the source gas nozzle 8, the reactive gas nozzle 9 preferably has a separate gas outlet on its inner or outer periphery to prevent deposits of group III compound semiconductor crystal from adhering to the inner wall surface of the manufacturing apparatus 1. The separate gas may be, but is not limited to, an inert gas, such as Ar or N2, or H2 gas.

[0047] The inner diameter of the reactive gas nozzle 9 is not particularly limited, but is preferably greater than 0 mm and less than 30 mm, more preferably greater than 3 mm and less than 15 mm. The inclination angle θa of the reactive gas nozzle 9 is not particularly limited, but is preferably greater than 0 degrees and less than 90 degrees, more preferably in the range of 5 to 60 degrees. The deflection angle θb of the reactive gas nozzle 9 is not particularly limited, but is preferably greater than 0 degrees and less than 90 degrees, more preferably in the range of 5 to 45 degrees.

[0048] In order to promote the growth of Group III compound semiconductor crystals in the crystal growth region S2, it is preferable to heat the reactive gas nozzle 9 and decompose the nitrogen-containing gas or oxygen-containing gas in the reactive gas nozzle 9 at a predetermined ratio. In this embodiment, the reactive gas nozzle 9 is heated by the first heater 14 of the heating unit 16 installed on the outer periphery thereof in the same manner as the raw material reaction chamber 2 described above.

[0049] <Gas flow channel> The gas flow channel 10 is composed of a first flow channel 10A, a second flow channel 10B, and a connecting portion 10C. As shown in FIG. 1, the first flow channel 10A is disposed so as to surround the source gas nozzle nozzle 8 and the reactive gas nozzle 9, and has a first opening 10A1. The second flow channel 10B is disposed downstream of the first flow channel 10A and has a second opening 10B1. The first flow channel 10A and the second flow channel 10B are connected via a connecting portion 10C at the first opening 10A1 and the second opening 10B1. The area of ​​the second opening 10B1 is configured to be larger than the area of ​​the first opening 10A1, and the width of the connecting portion 10C is configured to gradually increase from the first opening 10A1 to the second opening 10B1. In this embodiment, the shapes of first flow channel 10A and second flow channel 10B are cylindrical, but are not limited thereto and may be other shapes. The shape of connection portion 10C is preferably a shape that widens at a constant angle relative to the distance from first opening 10A1 in side view. In this embodiment, the shape is tapered as shown in FIG. 1 , but is not limited thereto and may be a connection portion having other shapes, such as a curved or stepped shape, in side view. At the connection position between connection portion 10C and second flow channel 10B, the angle α formed between the inner wall surface of connection portion 10C and the plane of second opening 10B1 is not particularly limited, but is preferably greater than 0 degrees and less than 90 degrees, more preferably in the range of 30 to 60 degrees.

[0050] The connection position between first flow channel 10A and connection part 10C is not particularly limited, but is preferably located above upper surface 12a of substrate holding member 12. In the present embodiment, the difference between the vertical distance from the tip of the outlet of source gas nozzle 8 to upper surface 12a of substrate holding member 12 and the vertical distance from the tip of the outlet of source gas nozzle 8 to the plane of second opening 10B1 is preferably within 30%, more preferably within 10%, of the vertical distance from the tip of the outlet of source gas nozzle 8 to upper surface 12a of substrate holding member 12.

[0051] Furthermore, the difference between the area of ​​the first opening 10A1 and the area of ​​the second opening 10B1 minus the area of ​​the upper surface 12a of the substrate holder is not particularly limited, but is preferably within 50%, more preferably within 10%, of the area of ​​the first opening 10A1. Thus, the gas flow channel 10 forms a gas flow path through which the gases ejected from the source gas nozzle and the reactive gas nozzle flow within the reaction vessel 20. By maintaining a constant ratio between the cross-sectional area of ​​the first flow channel 10A on the upstream side of the gas flow path and the cross-sectional area of ​​the second flow channel 10B on the downstream side, the Group III element-containing gas and the reactive gas flow at a constant flow rate within the gas flow channel 10, preventing backflow of gases and preventing deposition of Group III compound semiconductor crystals on the inner wall surfaces of the manufacturing apparatus 1.

[0052] Furthermore, the difference between the area of ​​first opening 10A1 and the area of ​​upper surface 12a of the substrate holding member is not particularly limited, but is preferably within 30%, more preferably within 10%, of the area of ​​upper surface 12a of the substrate holding member. By maintaining a constant ratio between the area of ​​first opening 10A1 and the area of ​​upper surface 12a of the substrate holding member, the Group III element-containing gas sprayed from source gas nozzle 8 and the reactive gas sprayed from reactive gas nozzle 9 in first flow channel 10A flow within the gas flow path formed by gas flow channel 10 and are transported onto seed substrate 11 without spreading, thereby improving gas utilization efficiency.

[0053] The gas flow channel 10 may be made of, for example, quartz, carbon, ceramics such as SiC-coated carbon, PG-coated carbon, PBN-coated carbon, or SiC, or molybdenum, iron, cobalt, nickel, or an alloy containing these as its main component.

[0054] The Group III element-containing gas and the reactive gas flowing in the gas flow passage formed by the gas flow channel 10 are mixed in the mixing region S1. The mixing region S1 is preferably located upward from the surface of the seed substrate 11 toward the source gas nozzle 8. The mixed source gases react on the seed substrate 11 in the growth region S2, resulting in the growth of a Group III compound semiconductor crystal. To promote the reaction of the mixed source gases, the mixing region S1 and the growth region S2 are maintained at desired temperatures. In this embodiment, a second heater 15 of the heating unit is provided around the outer periphery of the mixing region S1 and the growth region S2. The temperature of the second heater 15 is preferably maintained between 900°C and 1400°C inclusive in order to grow a Group III compound semiconductor crystal.

[0055] As a result, it is possible to improve the efficiency of transporting the source gas to seed substrate 11, thereby improving the utilization efficiency of the source gas, and also to suppress adhesion of deposits to the inner wall surfaces of manufacturing apparatus 1. This makes it possible to improve the yield of manufacturing Group III compound semiconductor crystal.

[0056] Example 1 In Example 1, the conditions for the method of manufacturing GaN, which is one of the group III compound semiconductor crystals according to the embodiment of the present disclosure, were specifically designed as follows in the manufacturing apparatus 1 shown in Figure 1, and a GaN crystal was grown on a seed substrate 11. In addition, a thermal fluid analysis was performed using CAE (Computer Aided Engineering) under the same manufacturing conditions.

[0057] The inner diameter of the first flow channel 10A and the outer diameter of the substrate holding member 12 were both 120 mm, the inner diameter of the second flow channel 10B was 170 mm, and the angle α between the inner wall surface of the connection portion 10C and the plane of the second opening 10B1 was 45°. The second opening 10B1 was positioned at the same height as the surface of the substrate holding member 12. The inner diameter of the source gas nozzle 8 was 50 mm, and eight reactive gas nozzles 9 were installed, all with inner diameters of 5 mm. The inclination angle θa was 45° relative to the vertical downward direction, and the deflection angle θb was positioned so that each reactive gas nozzle 9 rotated 10° counterclockwise (direction A shown in Figure 2(b)) in the radial direction when viewed from above in Figure 2(b). The distance from the tip of the source gas nozzle 8 to the surface of the seed substrate 11 was 100 mm. The seed substrate 11 was a GaN single crystal with a diameter of 100 mm.

[0058] As growth conditions, metallic Ga was placed in the source container 3 as a starting Ga source, and the pressure was 1.0×10 5 Under a pressure of 1.0 x 10 Pa, H2O gas, generated from 5 SLM of H2 gas and 20 SCCM of O2 gas, was introduced from a reactive gas supply pipe 7 to generate Ga2O gas, which was then sprayed from a raw material gas nozzle 8 toward the GaN single crystal substrate in the crystal growth area. 5 SLM of H2 gas and 3 SLM of N2 gas were discharged from separate gas outlets located on the outer periphery of the raw material gas nozzle 8. Meanwhile, nitrogen-containing gases NH3 gas and N2 gas were used as reactive gases. A pressure of 1.0 x 10 5 Under a pressure of 1 Pa, 1 SLM of NH3 gas and 9 SLM of N2 gas were introduced and sprayed from the reactive gas nozzle 9 toward the GaN single crystal substrate. 10 SLM of H2 gas and 20 SLM of N2 gas were discharged from separate gas outlets provided on the inner and outer periphery of the reactive gas nozzle 9. Power was supplied to the first heater 14 on the outer periphery of the reaction vessel 20 so that the temperatures reached 1150°C and the second heater 15 reached 1200°C. The substrate holding member 12 was rotated at 1000 RPM.

[0059] Example 2 In Example 2, GaN crystal was grown on seed substrate 11 under the same conditions as in Example 1, except that the angle α between the inner wall surface of connecting portion 10C and the plane of second opening 10B1 in side view in Fig. 1 was set to 30 degrees and 60 degrees, respectively. In addition, a thermal fluid analysis was performed by CAE under the same manufacturing conditions.

[0060] Example 3 In Example 3, GaN crystal was grown on seed substrate 11 under the same conditions as in Example 1, except that in Figure 1, the vertical direction from substrate holding member 12 toward source gas nozzle 8 was defined as positive, and the position of second opening 10B1 (vertical distance T from second opening 10B1 to upper surface 12a of substrate holding member 12: shown in Figure 4, not shown in Figure 1) was set to -15 mm and +15 mm, respectively, relative to Example 1. In addition, a thermal fluid analysis was performed using CAE under the same manufacturing conditions.

[0061] (Comparative Example 1) 3 is a schematic cross-sectional view showing the configuration of Group III compound semiconductor crystal manufacturing apparatus 1A according to Comparative Example 1 of the present disclosure. In Comparative Example 1, in contrast to Example 1, the inner diameters of first flow channel 10A and second flow channel 10B were the same, 170 mm, but other than that, GaN crystal was grown on seed substrate 11 under the same conditions as in Example 1. In addition, a thermal fluid analysis was performed using CAE under the same manufacturing conditions.

[0062] (Reference example 1) 4 is a schematic cross-sectional view showing the configuration of a Group III compound semiconductor crystal manufacturing apparatus 1B according to Reference Example 1 of the present disclosure. In Reference Example 1, in contrast to Example 1, GaN crystal was grown on seed substrate 11 under the same conditions as in Example 1, except that the angle α between the inner wall surface of connecting portion 10C and the plane of second opening 10B1 in side view was set to 0 degrees. In addition, a thermal fluid analysis was performed using CAE under the same manufacturing conditions.

[0063] For each of Examples 1-3, Comparative Example 1, and Reference Example 1, thermal fluid analysis was performed to evaluate the deposition rate of deposits made of Group III compound semiconductor crystals on the inner wall surface of the gas flow channel 10 and the growth rate and in-plane distribution of GaN on the GaN single crystal substrate. The deposition rate of deposits on the inner wall surface of the gas flow channel 10 was evaluated at three locations: heights P1, P2, and P3, as shown in Figures 1, 3, and 4. P2 was the inner wall surface of the gas flow channel 10 at the same height as the upper surface 12a of the substrate holding member 12, and the vertical direction from the substrate holding member 12 toward the source gas nozzle 8 was defined as positive. P1 and P3 were the inner wall surface of the gas flow channel 10 at heights 35 mm (d1) and −35 mm (d2) away from P2, respectively. The deposition rate of deposits at each of the three locations was calculated as the average value of four points in the circumferential direction. The in-plane distribution of the growth rate of GaN crystal grown on the GaN single crystal substrate was calculated by dividing the standard deviation by the average value.

[0064] The evaluation results for Example 1 and Comparative Example 1 are shown in Table 1. As shown in Table 1, the deposition rate of deposits on the inner wall surface of flow channel 10 decreased in the order of P3, P2, and P1, i.e., toward the upstream side. It was found that the deposition rate of deposits at P1 on the inner wall surface of flow channel 10, located upstream of seed substrate 11, was about four times slower in Example 1 than in Comparative Example 1. The in-plane distribution of the growth rate of GaN crystals on seed substrate 11 was about 1.7 times higher in Comparative Example 1 than in Example 1.

[0065] [Table 1]

[0066] Since the adhesion of deposits to the inner wall surface of gas flow channel 10 upstream of seed substrate 11 has the greatest effect on the incorporation of particles generated from deposits into Group III compound semiconductor crystal on seed substrate 11, a slower deposition rate at P1 upstream of seed substrate 11 indicates less particle incorporation into Group III compound semiconductor crystal. Furthermore, the in-plane distribution of the growth rate of GaN crystal on seed substrate 11 is a parameter that represents the uniformity of GaN crystal growth on seed substrate 11. In other words, a lower value for the in-plane distribution of growth rate indicates more uniform growth of GaN crystal on seed substrate 11. Therefore, the results shown in Table 1 confirm that Example 1, compared to Comparative Example 1, suppresses the generation of deposits upstream of seed substrate 11 and grows GaN crystal more uniformly on seed substrate 11.

[0067] Next, the evaluation results of Examples 1 and 2, Reference Example 1, and Comparative Example 1 are shown in Table 2. The results shown in Table 2 reveal that Examples 1 and 2 and Reference Example 1 all provide better results than Comparative Example 1 in terms of the deposition rate of deposits at P1 on the inner wall surface of flow channel 10 located upstream of seed substrate 11, and in the in-plane distribution of the growth rate of GaN on seed substrate 11. Furthermore, it was confirmed that Example 1 suppressed the generation of deposits upstream of seed substrate 11 and allowed GaN crystals to grow more uniformly on seed substrate 11.

[0068] [Table 2]

[0069] Next, the evaluation results of Examples 1 and 3 are shown in Table 3. The results shown in Table 3 reveal that the deposition rate of deposits at P1 on the inner wall surface of flow channel 10 became slower as the position (T) of second opening 10B1 became lower. Furthermore, when the position (T) of second opening 10B1 was −15 mm, the deposition rate of deposits at P2 on the inner wall surface of flow channel 10 became significantly faster than in Example 1, and it was confirmed that the growth rate of GaN crystal on seed substrate 11 was slightly slower and the in-plane distribution of the growth rate was slightly higher.

[0070] [Table 3]

[0071] Figure 5 shows a photograph (a) of the appearance of a GaN substrate grown on a seed substrate according to Example 1, and a photograph (b) of the appearance of a GaN substrate grown on a seed substrate according to Comparative Example 1. The number of pits and through-holes on the surface of the grown GaN was 9 in Figure 5(a) and 60 in Figure 5(b). This is presumably due to deposits adhering to the inner wall surface of the flow channel 10 becoming particles and mixing into the GaN film on the GaN single crystal substrate. In other words, it was confirmed that by suppressing the adhesion of deposits to the inner wall surface of the flow channel upstream of the GaN single crystal substrate surface, the incorporation of particles into the GaN growth film was suppressed, and the number of pits and through-holes on the surface of the grown GaN was reduced.

[0072] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Industrial Applicability]

[0073] The Group III compound semiconductor crystal manufacturing apparatus of the present disclosure can suppress the generation of deposits on the inner wall surfaces of the apparatus upstream of the seed substrate, and can suppress the incorporation of particles into the Group III compound semiconductor crystal growing on the seed substrate, thereby improving the yield of Group III compound semiconductor crystal manufacturing.

[0074] Group III compound semiconductor crystals obtained by the Group III nitride semiconductor crystal manufacturing apparatus according to the present invention can be used, for example, in optical devices such as light-emitting diodes and laser diodes, electronic devices such as rectifiers and bipolar transistors, and semiconductor sensors such as temperature sensors, pressure sensors, radiation sensors, and visible-ultraviolet light detectors. However, the present invention is not limited to the above-mentioned uses and can be applied in a wide range of fields. [Explanation of symbols]

[0075] 1. III-group compound semiconductor crystal manufacturing equipment 2 Raw material reaction chamber 3 Raw material container 4 Starting Ga source 5 Raw material reaction section 6 Crystal growth section 7. Reactive gas supply pipe 8. Source gas nozzle 9 Reactive Gas Nozzle 10 Gas Flow Channels 10A First Flow Channel 10B Second flow channel 10C connection 11 types of substrate 12 Substrate holding member 13 Rotating shaft 14 First heater 15 Second heater 16 Heating section 17 Exhaust port 20 reaction vessel S1 mixed area S2 crystal growth region

Claims

1. a substrate holding member for holding a seed substrate; a gas flow channel forming a gas flow path through which gas flows toward the substrate holding member; Equipped with the gas flow channel has a junction portion having a downstream inner diameter that is larger than an upstream inner diameter; an upper surface of the substrate holding member is disposed within the connecting portion; Equipment for manufacturing Group III compound semiconductor crystals.

2. a difference between an area of ​​a region surrounded by the upstream end face of the connection portion and an area of ​​the upper surface is within 30% of the area of ​​the upper surface; 2. The apparatus for producing a Group III compound semiconductor crystal according to claim 1.

3. When the area of ​​the region surrounded by the upstream end face of the connection portion is S1, the area of ​​the region surrounded by the downstream end face of the connection portion is S2, and the area of ​​the upper surface is S3, -50%≦((S2-S3)-S1) / S1≦50% is satisfied.

2. The apparatus for producing a Group III compound semiconductor crystal according to claim 1.

4. Further comprising a raw material reaction section and a reactive gas nozzle, the raw material reaction section includes a raw material reaction chamber that generates a Group III element-containing gas, and a raw material gas nozzle that guides the generated Group III element-containing gas from the raw material reaction chamber and injects it toward the crystal growth section, the reactive gas nozzle injects a reactive gas toward the seed substrate to react with the Group III element-containing gas to produce the Group III compound semiconductor crystal; the nozzle of the source gas nozzle and the nozzle of the reactive gas nozzle are surrounded by the gas flow channel; 2. The apparatus for producing a Group III compound semiconductor crystal according to claim 1.

5. a difference between a vertical distance from the source gas nozzle to the upper surface of the substrate holding member and a vertical distance from an injection port of the source gas nozzle to a downstream end face of the connection portion is within 30% of the vertical distance from the source gas nozzle to the upper surface; 5. The apparatus for producing a Group III compound semiconductor crystal according to claim 4.

6. the source gas nozzle is disposed so that the injection direction of the injection port faces the upper surface.

5. The apparatus for producing a Group III compound semiconductor crystal according to claim 4.

7. the reactive gas nozzle is disposed so that the jet direction of the jet port is inclined with respect to the upper surface; 5. The apparatus for producing a Group III compound semiconductor crystal according to claim 4.

8. When viewed from above, the reactive gas nozzle is disposed such that the jet direction of the jet port is deflected with respect to a radial direction from a rotation axis of the substrate holding member.

5. The apparatus for producing a Group III compound semiconductor crystal according to claim 4.

9. an imaginary line extending in a spray direction of the source gas nozzle and an imaginary line extending in a spray direction of the reactive gas nozzle intersect between the source gas nozzle and the reactive gas nozzle in a side view; 6. The apparatus for producing a Group III compound semiconductor crystal according to claim 5.

Images