Group III nitride crystallization manufacturing apparatus

Abstract

The present invention provides a group III nitride crystal manufacturing apparatus capable of monitoring the corrosion state of the refrigerant circulation section that circulates the refrigerant. [Solution] The Group III nitride crystal manufacturing apparatus is a Group III nitride crystal manufacturing apparatus for growing Group III nitride crystals on a substrate, comprising: a vertical reaction vessel extending in the vertical direction; and a cooling unit provided on the outer periphery of the reaction vessel, which supplies refrigerant to a refrigerant circulation unit from a refrigerant supply port provided vertically below, cools the reaction vessel by flowing the refrigerant into the refrigerant circulation unit from vertically below to vertically above, and discharges the refrigerant from the refrigerant circulation unit through a refrigerant discharge port provided vertically above, wherein the cooling unit is provided vertically below the refrigerant supply port and has a refrigerant retention unit for retaining refrigerant, and a drain water discharge port for discharging the refrigerant retained in the refrigerant retention unit.

Description

Technical Field

[0001] The present disclosure relates to a group III nitride crystal manufacturing apparatus. In particular, the present disclosure relates to a group III nitride crystal manufacturing apparatus capable of monitoring the corrosion state of a refrigerant circulation unit that circulates a refrigerant for cooling a reaction vessel.

Background Art

[0002] Group III nitride semiconductors are used in fields such as optical devices including semiconductor lasers and light-emitting diodes, as well as high-frequency or high-power electronic devices. These semiconductors have attracted particular attention in recent years because they are expected to reduce switching loss during power conversion compared with silicon-based devices.

[0003] Group III nitride crystals are produced by, for example, a hydride vapor phase epitaxy method (hereinafter also referred to as HVPE method) and an oxide vapor phase epitaxy method (hereinafter also referred to as OVPE method).

[0004] In general, in a production method by vapor phase growth, cooling water may be caused to flow in the outer peripheral portion of the reaction vessel to cool the reaction vessel (see, for example, Patent Document 1). At this time, instead of clean water, wastewater from other processes or the like may be secondarily used as cooling water. When water containing chlorine ions or the like or dirty water containing rust or the like is secondarily used as cooling water, the cooling efficiency decreases due to adhesion and precipitation of foreign matter, and the corrosion of pipes through which the cooling water flows progresses, which may cause water leakage.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0006] In the cooling water piping example described above, there was a problem in that the reduction in cooling efficiency due to the adhesion and sedimentation of foreign matter, and the progression of corrosion in the piping carrying the cooling water, which could lead to water leaks, could not be detected until a final water leak occurred.

[0007] Therefore, the present disclosure aims to provide a group III nitride crystal manufacturing apparatus that can monitor the corrosion state of the refrigerant circulation section that circulates the refrigerant, even when water containing chloride ions or other contaminated water containing rust or other contaminated water is reused as cooling water. [Means for solving the problem]

[0008] The Group III nitride crystal manufacturing apparatus according to this disclosure is a Group III nitride crystal manufacturing apparatus for producing Group III nitride crystals by growing Group III nitride crystals on a substrate, comprising: a vertical reaction vessel extending in the vertical direction; and a cooling unit provided on the outer periphery of the reaction vessel, which supplies refrigerant to a refrigerant circulation unit from a refrigerant supply port provided vertically below, cools the reaction vessel by flowing the refrigerant into the refrigerant circulation unit from vertically below to vertically above, and discharges the refrigerant from the refrigerant circulation unit through a refrigerant discharge port provided vertically above, wherein the cooling unit is provided vertically below the refrigerant supply port and has a refrigerant retention section for retaining refrigerant, and a drain water discharge port for discharging the refrigerant retained in the refrigerant retention section. [Effects of the Invention]

[0009] The Group III nitride crystal manufacturing apparatus according to this disclosure includes a refrigerant retention section provided vertically below the refrigerant supply port for retaining refrigerant, and a drain water outlet for discharging the refrigerant retained in the refrigerant retention section. Therefore, even when water containing chloride ions or other contaminated water containing rust is reused as cooling water, the corrosion state of the refrigerant circulation section that circulates the refrigerant can be monitored. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing the cross-sectional structure of a group III nitride crystal manufacturing apparatus according to Embodiment 1. [Figure 2]Figure 1 is a schematic partially transparent front view showing the configuration of the cooling section located on the outer circumference of the reaction vessel of the group III nitride crystal manufacturing apparatus, as seen through a partial view from the front. [Figure 3] This is a schematic cross-sectional view showing the cross-sectional structure as seen from direction AA in Figure 2. [Modes for carrying out the invention]

[0011] A Group III nitride crystal manufacturing apparatus according to the first embodiment is a Group III nitride crystal manufacturing apparatus for producing Group III nitride crystals by growing Group III nitride crystals on a substrate, comprising: a vertical reaction vessel extending in the vertical direction; and a cooling unit provided on the outer periphery of the reaction vessel, which supplies refrigerant to a refrigerant circulation unit from a refrigerant supply port provided vertically below, cools the reaction vessel by flowing the refrigerant into the refrigerant circulation unit from vertically below to vertically above, and discharges the refrigerant from the refrigerant circulation unit through a refrigerant discharge port provided vertically above, wherein the cooling unit is provided vertically below the refrigerant supply port and has a refrigerant retention unit for retaining refrigerant, and a drain water discharge port for discharging the refrigerant retained in the refrigerant retention unit.

[0012] In the second embodiment of the group III nitride crystal manufacturing apparatus, the drain water outlet may be located at the bottom of the refrigerant retention section, as in the first embodiment.

[0013] In the third embodiment of the group III nitride crystal manufacturing apparatus, the refrigerant circulation section may have a partition plate that changes the direction of flow of the refrigerant, as in the first or second embodiment described above.

[0014] The fourth embodiment of the group III nitride crystal manufacturing apparatus, in any of the first to third embodiments described above, has a reaction vessel comprising a raw material supply section and a crystal growth section, wherein the raw material supply section includes a raw material gas nozzle for supplying a group III element-containing gas toward the crystal growth section and a nitrogen element-containing gas nozzle for supplying a nitrogen element-containing gas toward the crystal growth section, and the crystal growth section may include a substrate holding member for holding a substrate on its upper surface for growing group III nitride crystals.

[0015] Hereinafter, a group III nitride crystal manufacturing apparatus according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0016] (Embodiment 1) <Overview of Group III Nitride Crystal Manufacturing Apparatus> Figure 1 is a schematic cross-sectional view showing a cross-sectional structure of a group III nitride crystal manufacturing apparatus 100 according to Embodiment 1. For convenience, the vertically upward direction is defined as the Z direction, and the rightward direction in the horizontal plane is defined as the X direction. The overview of the group III nitride crystal manufacturing apparatus according to Embodiment 1 will be described with reference to Figure 1.

[0017] In Figure 1, the size, ratio, and the like of each constituent member may differ from the actual ones. The group III nitride crystal manufacturing apparatus 100 according to Embodiment 1 is a group III nitride crystal manufacturing apparatus that manufactures a group III nitride crystal by causing crystal growth of the group III nitride crystal on a substrate. Specifically, the group III nitride crystal manufacturing apparatus 100 includes a vertical reaction vessel 60 extending in the vertical direction, and a cooling unit 30 provided on the outer peripheral portion of the reaction vessel 60. The cooling unit 30 supplies a coolant to the coolant circulation unit 32 from a coolant supply port 34 provided vertically below, causes the coolant 39 to flow in the coolant circulation unit 32 from the vertically lower side to the vertically upper side to cool the reaction vessel 60, and discharges the coolant 39 from the coolant circulation unit 32 via a coolant discharge port 36 provided vertically above. Further, the cooling unit 30 has a coolant retention unit 40 that is provided vertically below the coolant supply port 34 and retains the coolant 39, and a drain water discharge port 42 that discharges the coolant 39 retained in the coolant retention unit 40. Thereby, even when water containing chlorine ions or the like or dirty water containing rust or the like is secondarily used as cooling water, the corrosion state of the coolant circulation unit 32 that circulates the coolant 39 can be monitored by inspecting the coolant 39 discharged from the drain water discharge port 42.

[0018] Each member constituting this group III nitride crystal manufacturing apparatus 100 will be described below. Note that the group III nitride crystal manufacturing apparatus 100 may have two or more tanks including one tank having the crystal growth unit 20 inside.

[0019] <Reaction Vessel> The reaction vessel 60 is of a vertical type extending in the vertical direction. The reaction vessel 60 may include a raw material supply unit (not shown) and a crystal growth unit 20. The raw material supply unit may include a raw material gas nozzle 66 that supplies a group III element-containing gas toward the crystal growth unit 20, and a nitrogen element-containing gas nozzle 68 that supplies a nitrogen element-containing gas toward the crystal growth unit 20.

[0020] <Crystal Growth Unit> The crystal growth unit 20 may include a substrate holding member 10 that holds the substrate 14 for growing a group III nitride crystal on its upper surface.

[0021] <Substrate Holding Unit> The substrate holding unit 10 carries the substrate 14 and is rotated by a rotating shaft 12. For example, it rotates at 1500 rpm.

[0022] <Heater> The crystal growth unit 20 is heated by heaters 64a and 64b.

[0023] <Cooling Unit> The cooling unit 30 has a refrigerant circulation part 32, a refrigerant retention part 40, and a drain water discharge port 42. Refrigerant is supplied to the refrigerant circulation part 32 from a refrigerant supply port 34 provided vertically downward. Next, the refrigerant 39 is caused to flow in the refrigerant circulation part 32 from vertically downward to vertically upward to cool the reaction vessel 60. Thereafter, the refrigerant 39 is discharged from the refrigerant circulation part 32 via a refrigerant discharge port 36 provided vertically upward. The refrigerant retention part 40 is provided at the lower outer peripheral portion of the reaction vessel 60 vertically below the refrigerant supply port 34, and retains part of the refrigerant supplied from the refrigerant supply port 34. The drain water discharge port 42 discharges the refrigerant 39 retained in the refrigerant retention part 40, and can appropriately monitor the corrosion state of the refrigerant circulation part 32 that circulates the refrigerant. Note that the refrigerant 39 may be, for example, water.

[0024] <Refrigerant Circulation Part> FIG. 2 is a schematic partially transparent front view showing a partially transparent configuration from the front of the cooling unit 30 provided on the outer periphery of the reaction vessel 60 of the group III nitride crystal manufacturing apparatus 100 of FIG. 1. The refrigerant circulation unit 32 receives refrigerant from a refrigerant supply port 34 located vertically downward, and cools the reaction vessel 60 by circulating the refrigerant 39 from vertically downward to vertically upward. After that, the refrigerant 39 is discharged from the refrigerant circulation unit 32 through a refrigerant discharge port 36 located vertically upward.

[0025] <Partition board> Furthermore, the refrigerant circulation unit 32 may have partition plates 38a, 38b, and 38c that change the direction of refrigerant flow. This allows the refrigerant circulation unit 32 to cause the refrigerant 39 to flow around the outer circumference of the reaction vessel 60 from vertically below to vertically above, in a clockwise spiral when viewed from vertically above. In Figures 1 and 2, three partition plates 38a, 38b, and 38c are provided, but this is not limited to this. To circulate around the outer circumference of the reaction vessel 60 two or more times, for example, there may be one, two, or four or more. Also, in Figures 1 and 2, the partition plates 38a, 38b, and 38c change the direction of refrigerant flow twice by 90 degrees, but this is not limited to this, and the direction of refrigerant flow may be changed at an angle of less than 90 degrees.

[0026] <Refrigerant supply port and refrigerant discharge port> The refrigerant supply port 34 is located vertically downward, and the refrigerant discharge port 36 is located vertically upward. Multiple refrigerant discharge ports 36 may be provided.

[0027] <Refrigerant accumulation area and drain water outlet> Figure 3 is a schematic cross-sectional view showing the cross-sectional structure as seen from the AA direction in Figure 2. The refrigerant retention section 40 is located vertically below the refrigerant supply port 34 and retains the refrigerant 39. This allows for cooling of, for example, the O-ring at the bottom of the reaction vessel 60. The drain water outlet 42 is located vertically below the refrigerant supply port 34 and discharges the refrigerant 39 that has accumulated in the refrigerant retention section 40. The drain water outlet 42 may be located at the very bottom of the refrigerant retention section 40. This allows for the discharge of all the refrigerant 39 that has accumulated in the refrigerant retention section 40. Furthermore, as shown in Figure 3, the drain water outlets 42 may be provided at three locations in the XY plane, for example, at 90 degrees to the left and right of the center of the reaction vessel 60, and at 180 degrees opposite the center, relative to the refrigerant supply port 34. In addition, they may be provided at one, two, or four or more locations. This reduces the amount of refrigerant 39 that remains locally. [Industrial applicability]

[0028] According to the Group III nitride crystal manufacturing apparatus described herein, even when water containing chloride ions or other contaminated water containing rust or other substances is reused as cooling water, the corrosion state of the refrigerant circulation section that circulates the refrigerant can be monitored. [Explanation of symbols]

[0029] 10 Board holding part 12-rotation shaft 14 circuit boards 20 Crystal growth section 30 Cooling section 32 Refrigerant circulation section 34 Refrigerant supply port 36 Refrigerant drain outlet 38a, 38b, 38c Partition plates 39 Refrigerant 40 Refrigerant retention area 42 Drain water outlet 60 reaction vessels 64a Heating heater 64b Heating heater 66. Raw material gas nozzle 68 Nitrogen-containing gas nozzles 100 Group III nitride crystal manufacturing equipment

Claims

1. A group III nitride crystal manufacturing apparatus for producing group III nitride crystals by growing group III nitride crystals on a substrate, A vertical reaction vessel extending in the vertical direction, A cooling unit is provided on the outer periphery of the reaction vessel, which supplies refrigerant to a refrigerant circulation unit from a refrigerant supply port located vertically downward, flows the refrigerant into the refrigerant circulation unit from vertically downward to vertically upward to cool the reaction vessel, and discharges the refrigerant from the refrigerant circulation unit through a refrigerant discharge port located vertically upward, Equipped with, The cooling section is provided vertically below the refrigerant supply port and includes a refrigerant retention section for retaining the refrigerant and a drain water outlet for discharging the refrigerant retained in the refrigerant retention section, wherein the apparatus is for manufacturing group III nitride crystals.

2. The group III nitride crystal manufacturing apparatus according to claim 1, wherein the drain water outlet is provided at the lowest part of the refrigerant retention section.

3. The apparatus for manufacturing group III nitride crystals according to claim 1, wherein the refrigerant circulation section has a partition plate that changes the direction of flow of the refrigerant.

4. The reaction vessel has a raw material supply section and a crystal growth section. The raw material supply unit includes a raw material gas nozzle that supplies a Group III element-containing gas toward the crystal growth unit, and a nitrogen element-containing gas nozzle that supplies a nitrogen element-containing gas toward the crystal growth unit. The apparatus for manufacturing group III nitride crystals according to any one of claims 1 to 3, wherein the crystal growth section includes a substrate holding member that holds a substrate on which group III nitride crystals are grown on its upper surface.

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