Gallium oxide single crystal particles and method for producing same

Abstract

A gallium oxide single crystal grain according to the present invention is an α-Ga2O3 single crystal grain that has a diameter and a height of more than 100 μm.

Description

[Technical field]

[0001] The present invention relates to gallium oxide single crystal particles and a method for producing the same. [Background technology]

[0002] In recent years, gallium oxide (Ga 2 O 3 Gallium oxide is known to have five crystal forms: α, β, γ, δ, and ε. Among these, the metastable phase α-Ga 2 O 3 has a very large band gap of 5.3 eV and is expected to be used as a material for power semiconductors. For example, Patent Document 1 discloses a semiconductor device including a base substrate having a corundum type crystal structure, a semiconductor layer having a corundum type crystal structure, and an insulating film having a corundum type crystal structure. 2 O 3 Patent Document 2 discloses an example of forming a film on a c-plane sapphire substrate. Patent Document 2 also discloses a semiconductor device including an n-type semiconductor layer mainly composed of a crystalline oxide semiconductor having a corundum structure, a p-type semiconductor layer mainly composed of an inorganic compound having a hexagonal crystal structure, and an electrode. In the example of Patent Document 2, an α-Ga 2 O 4 SiO 2 , which has a metastable corundum structure, is formed on a c-plane sapphire substrate as an n-type semiconductor layer. 2 O 3 The film is a p-type semiconductor layer with a hexagonal crystal structure, 2 O 3 It is disclosed that a diode can be fabricated by forming a film of α-Ga 2 O 3 It is also expected to be applied to phosphors. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-72533 A [Patent Document 2] JP 2016-25256 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the large α-Ga 2 O 3 Single crystal particles have not been previously known.

[0005] The present invention has been made to solve these problems, and a main object of the present invention is to provide large gallium oxide single crystal particles. [Means for solving the problem]

[0006] The gallium oxide single crystal particles of the present invention are α-Ga 2 O 3 It is a single crystal particle, the diameter and height of which exceed 100 μm. [Brief description of the drawings]

[0007] [Figure 1] FIG. [Diagram 2] FIG. 1 is a schematic diagram of a hydrothermal synthesis system 20. [Diagram 3] XRD profile of the product obtained in Example 1. [Figure 4] SEM image of the product obtained in Example 1. [Diagram 5] 4 is a Raman spectrum of the product obtained in Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A preferred embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a vertical cross-sectional view of a pressure vessel 10, and Fig. 2 is a schematic diagram of a hydrothermal synthesis system 20.

[0009] The gallium oxide single crystal particles of the present embodiment are α-Ga 2 O 3The particles are single crystal particles having a diameter and height exceeding 100 μm (preferably exceeding 200 μm).

[0010] The gallium oxide single crystal particles of this embodiment have a Raman shift of 690 cm -1 The half-width of the closest Raman peak is 20 cm -1 It is preferable that:

[0011] The gallium oxide single crystal particles of this embodiment preferably have a crystal surface roughness Ra of 100 nm or less.

[0012] In the gallium oxide single crystal particles of the present embodiment, the ratio of Ga atoms to O atoms is preferably 0.70 to 1.00. 2 O 3 ) crystal, the ratio of Ga atoms to O atoms is 0.67.

[0013] Next, a method for producing gallium oxide single crystal particles of this embodiment will be described. In one example of the method for producing gallium oxide single crystal particles, an aqueous solution containing Ga ions is adjusted to a pH of preferably 9.0 to 11.0, and brought to a supercritical state at a temperature of 390° C. or higher (preferably 400° C. or higher) and a pressure of 22.1 MPa or higher. By adjusting the pH, α-Ga 2 O 3 Single crystal particles are preferentially formed.

[0014] Examples of the aqueous solution containing Ga ions include an aqueous gallium halide solution, an aqueous gallium nitrate solution, an aqueous gallium sulfate solution, and an aqueous gallium hydroxide solution. Examples of the gallium halide solution include gallium chloride, gallium bromide, and gallium iodide. The aqueous solution containing Ga ions is adjusted to a pH of preferably 9.0 to 11.0 (more preferably 9.6 to 10.4, and even more preferably 9.8 to 10.2) with a pH adjuster. As the pH adjuster, an aqueous solution of an alkali metal hydroxide (e.g., a KOH aqueous solution) or an aqueous solution containing ammonium ions (e.g., ammonium water) may be used. The Ga ion concentration of the aqueous solution containing Ga ions is not particularly limited, but may be, for example, 0.1 M or more and 10 M or less. Gallium oxyhydroxide (GaOOH) may be added to the aqueous solution containing Ga ions. In this way, gallium oxyhydroxide also functions as a Ga source, so that α-Ga 2 O 3 The amount of crystals produced can be increased. The timing of adding gallium oxyhydroxide may be either before or after adjusting the pH. The aqueous solution containing Ga ions may contain an alkali metal element (alkali metal ion). Examples of alkali metals include Li, Na, and K.

[0015] In order to bring the aqueous solution containing Ga ions into a supercritical state at a temperature of 390°C or more and a pressure of 22.1 MPa or more, it is preferable to put the aqueous solution containing Ga ions into a pressure-resistant container and adjust the temperature to 390°C or more and the pressure to 22.1 MPa or more. The pressure is determined by the internal volume of the pressure-resistant container, the amount of the aqueous solution put into the pressure-resistant container, the temperature inside the pressure-resistant container, and the setting of the pressure regulating valve. The reaction time is not particularly limited, but may be, for example, 0.5 hours or more and 100 hours or less. After the reaction is completed, the temperature inside the pressure-resistant container is lowered, and the product, gallium oxide single crystal particles, are taken out from the pressure-resistant container. A seed crystal may be immersed in the aqueous solution containing Ga ions. The seed crystal may be α-Ga 2 O 3 Single crystals, especially α-Ga with diameter and height exceeding 100μm 2 O 3 Single crystals are included.

[0016] When it is desired to obtain gallium oxide single crystal particles containing a dopant, it is sufficient to add ions corresponding to the dopant to the aqueous solution containing Ga ions. Examples of dopants include Group 14 elements such as carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb). By adding a dopant to the gallium oxide single crystal particles, the conductivity of the gallium oxide single crystal particles can be controlled.

[0017] An example of a pressure-resistant container is shown in Fig. 1. The pressure-resistant container 10 in Fig. 1 is made of stainless steel, and has a lid 12 with a male thread and a protrusion 12a screwed onto a female thread provided at the opening of a bottomed cylindrical container body 11. The internal volume of the pressure-resistant container 10 is preferably 50 mL or more. The container body 11 of the pressure-resistant container 10 contains an aqueous solution 14 containing Ga ions. The aqueous solution 14 is preferably adjusted to a pH of 9.0 to 11.0 (more preferably 9.6 to 10.4, and even more preferably 9.8 to 10.2).

[0018] FIG. 2 is a schematic diagram of a hydrothermal synthesis system 20. In this hydrothermal synthesis system 20, a pressure vessel 10 is set in an electric furnace housing 22. A heater 24 and a thermocouple 26 for measuring the temperature inside the furnace are attached inside the electric furnace housing 22. A pressure vessel thermocouple 28 for measuring the internal temperature of the pressure vessel 10 is attached to the pressure vessel 10. The power supplied to the heater 24 is controlled so that the furnace temperature measured by the thermocouple 26 for measuring the temperature inside the furnace becomes the set temperature. A pipe 30 is connected to the pressure vessel 10. One end 30a of the pipe 30 is disposed inside the pressure vessel 10, and the other end 30b of the pipe 30 is disposed in the atmosphere. The pipe 30 is cooled by cooling water in a cooling water tank 40. A pressure gauge 32, a safety valve 34, and a pressure regulating valve 36 are attached to the pipe 30 between the cooling water tank 40 and the other end 30b. The entire pressure vessel 10 is heated by the heater 24 so that the internal temperature of the pressure vessel 10 is 390°C or higher (preferably 400°C or higher) and the internal pressure of the pressure vessel 10 is 22.1 MPa or higher. The internal pressure of the pressure vessel 10 is determined by the internal volume of the pressure vessel 10, the amount of the aqueous solution 14 put into the pressure vessel 10, the temperature inside the vessel, and the setting of the pressure regulating valve 36. Therefore, the amount of the aqueous solution 14 put into the pressure vessel 10 may be adjusted so that the pressure inside the vessel is 22.1 MPa or higher when the temperature inside the vessel is 390°C or higher. This state is maintained for a predetermined time, and then the internal temperature of the pressure vessel 10 is cooled to room temperature, and the solution containing the crystals is removed from the pressure vessel 10, rinsed with pure water, and then dried in a dryer.

[0019] As described above, the gallium oxide single crystal particles of the present embodiment are large particles that have not been known until now, and therefore are expected to find new applications as semiconductor materials.

[0020] In addition, in the gallium oxide single crystal particles of this embodiment, the Raman shift of 690 cm -1 The half-width of the closest Raman peak is 20 cm -1 If the crystallinity is below this level, it is expected that the crystallinity will be good and that this will contribute to improving the performance of power devices, catalysts, and the like.

[0021] Furthermore, in the gallium oxide single crystal particles of this embodiment, if the surface roughness Ra of the crystal surface is 100 nm or less, the surface smoothness is high, making it easy to form a drift layer or an electrode with a controlled carrier concentration in a power device.

[0022] Furthermore, in the gallium oxide single crystal particles of this embodiment, if the ratio of Ga atoms to O atoms is 0.70 to 1.00, a certain degree of oxygen vacancy is contained, so that electrical conductivity is easily exhibited, making them suitable for power devices.

[0023] Furthermore, α-Ga 2 O 3 When the crystal is used in a power semiconductor or the like that requires high voltage resistance, high crystal quality is required because the dielectric breakdown field characteristics are affected by the crystal quality. Therefore, in the gallium oxide single crystal particle of this embodiment, it is preferable that the X-ray rocking curve half width of at least one of the (006) plane and the (104) plane is 300 arcsec or less, in other words, the crystallinity (crystal quality) is sufficiently high. The X-ray rocking curve half width of the (006) plane is more preferably 110 arcsec or less, and even more preferably 70 arcsec or less. The X-ray rocking curve half width of the (104) plane is more preferably 260 arcsec or less, and even more preferably 80 arcsec or less.

[0024] Furthermore, in the gallium oxide single crystal particles of this embodiment, the content of each alkali metal element is 1.2 × 10 15 ~1.0×10 18 atoms / cm 3 In this way, it is preferable that β-Ga 2 O 3 The formation of heterogeneous phases such as α-Ga 2 O 3 Crystals can be stably generated. Examples of alkali metal elements include Li, Na, and K. In addition, the total content of the alkali metal elements is 1.2 × 10 15 ~1.0×10 18 atoms / cm 3 It is more preferable that:

[0025] It goes without saying that the present invention is not limited to the above-described embodiment, and can be embodied in various forms within the technical scope of the present invention. EXAMPLES

[0026] EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the following examples in any way.

[0027] [Example 1] 1. Hydrothermal synthesis A 0.1M aqueous solution of gallium nitrate octahydrate (Kishida Chemical) was prepared, and the pH was adjusted to 10.0 using a 1M KOH aqueous solution as a pH adjuster to obtain a raw material solution. Next, 45 mL of the raw material solution was placed in a pressure-resistant container 10 (inner diameter 19 mm, internal volume 50 mL) made of SUS316 as shown in FIG. 1 and sealed. Next, the pressure-resistant container 10 was set in the electric furnace housing 22 of the hydrothermal synthesis system 20 shown in FIG. 2. The pressure regulating valve 36 was set in advance so that the internal pressure of the pressure-resistant container 10 was 24.0 MPa. Next, the entire pressure-resistant container 10 was heated by the heater 24 of the electric furnace housing 22, and the internal temperature of the pressure-resistant container 10 was set to 420°C. At this time, the internal pressure of the pressure-resistant container 10 was 24.0 MPa. This state was maintained for 5 hours. Thereafter, the internal temperature of the pressure-resistant container 10 was cooled to room temperature, and the generated particles were taken out of the pressure-resistant container 10, rinsed with pure water, and then dried in a dryer.

[0028] 2. Evaluation (1) Crystalline phase The particles obtained in 1 above were used to obtain an XRD profile under the following conditions using an XRD device (Rigaku, RINT-TTR III). As a result, the XRD profile shown in Figure 3 was obtained. As shown in Figure 3, α-Ga 2 O 3 was identified as the major phase of the product. X-ray tube Cu target Tube voltage: 50kV ·Tube current 300mA 2θ / θ method 2θ range: 10°~80°

[0029] (2) Microstructure and composition The particles obtained in 1 above were observed with a scanning electron microscope (SEM, JEOL JSM-IT500), and the crystals shown in Figure 4 were observed. No holes were observed in the crystals. The composition of the particle surface of one typical particle was confirmed by point analysis using an EDS device attached to the SEM. As a result, the elements detected were as shown in Table 1. The ratio of Ga atoms to O atoms was 0.79, which was within the range of 0.70 to 1.00.

[0030] (3) Particle shape and surface roughness The particle shape (diameter, height) of the particles obtained in 1 above was measured using a shape analysis laser microscope (Keyence VK-X150) by the following method. The particles were scattered on a flat plate made of metal Al coated with DLC (diamond-like carbon), and a typical single particle, in which the particles did not overlap, was observed and the following measurements were performed. The particle diameter was obtained by measuring the diameter in the vertical and horizontal directions for the image observed from above the particle and averaging them. In addition, a "profile measurement" was performed using the software attached to the laser microscope, and the maximum height from the DLC-coated metal Al plate surface was taken as the particle height. As a result, the particle diameter and particle height shown in Table 1 were obtained. Both the particle diameter and particle height were over 100 μm. In addition, the surface roughness Ra of the particle surface was measured using the "line roughness measurement" mode of the attached software using the same shape analysis laser microscope as above. The length of the measurement area was set to 10 μm. As a result, the surface roughness Ra shown in Table 1 was obtained. The surface roughness Ra was 34 nm, which was less than 100 nm.

[0031] (4) Raman peak half-width The Raman spectrum was measured for the particles obtained in 1 above. The particles used were different from those observed in 2.(2) and (3) above. The Raman spectrum was measured using a laser Raman spectrometer LabRAM ARAMIS manufactured by Horiba, Ltd., and the operation software LabSpec (Ver. 5.78). The optical system was a Czerny-Turner type spectroscopic system, backscattering type, and a semiconductor pumped solid-state laser (DPSS, 532 nm) was used as the light source. Before measuring the sample, calibration was performed using a Si wafer. The Raman spectrum of the particles was measured with the laser output adjusted to 24 mW, the Hole (confocal hole diameter) set to 400 μm, and the central wave number of the spectrometer set to 520 cm. -1 The slit was 100 μm, the grating was 1800 gr / mm, the objective lens was 100x, and the analysis was performed in point analysis mode. The exposure time was 60 seconds, the number of integrations was 2, and the wavenumber range was 100 to 900 cm. -1 The neutral density filter was appropriately set so that the count of the strongest peak was between 3000 and 50000. In addition, a Ne lamp was used during the measurement, and the wave number of the peak top due to the Ne lamp emission line in the obtained spectrum was 278.28 cm. -1 The spectrum was corrected so that the baseline was corrected as follows: The baseline was corrected by setting the functions of the software LabSpec to "Type" as "Lines", "Degree" as "5", "Attach" as "No", "Style" as "-", and "Auto". The spectrum obtained in this way was corrected for the Raman shift of 690 cm -1 The half-width of the peak was calculated as the width at half maximum, which is the width at half the height of the count number of the peak top closest to the particle. The results are shown in Table 1. The measured Raman spectrum is shown in Figure 5. The half-width of the particle is 20 cm -1 The results were as follows.

[0032] [Example 2] Particles were synthesized under the same conditions as in Example 1, except that the pressure regulating valve 36 of the hydrothermal synthesis system 20 was set to 30.0 MPa and the internal pressure of the pressure-resistant vessel 10 at 420°C was set to 30.0 MPa. The XRD spectrum of the obtained particles was measured in the same manner as in 2.(1) above. 2 O 3 was identified as the main phase of the product. Evaluation was performed in the same manner as in 2.(2) to (4) above. The results are shown in Table 1. That is, the particle size and particle height were more than 100 μm, the surface roughness Ra of the particles was 100 nm or less, and the Raman shift was 690 cm -1 The half-width of the closest Raman peak is 20 cm -1 or less, and the atomic ratio of Ga / O was within the range of 0.70 to 1.00. Furthermore, as a result of observing the obtained particles by SEM, no holes were observed in the crystals.

[0033] [Example 3] Particles were synthesized under the same conditions as in Example 2, except that the holding time at the maximum temperature was 24 hours. The XRD spectrum of the obtained particles was measured in the same manner as in 2.(1) above. 2 O 3 was identified as the main phase of the product. Evaluation was performed in the same manner as in 2.(2) to (4) above. The results are shown in Table 1. That is, the particle size and particle height were more than 100 μm, the surface roughness Ra of the particles was 100 nm or less, and the Raman shift was 690 cm -1 The half-width of the closest Raman peak is 20 cm -1 or less, and the atomic ratio of Ga / O was within the range of 0.70 to 1.00. Furthermore, as a result of observing the obtained particles by SEM, no holes were observed in the crystals.

[0034] [Example 4] Particles were synthesized under the same conditions as in Example 1, except that 20 mg of the particles obtained under the conditions in Example 3 were added as seed crystals to the raw material solution. The XRD spectrum of the obtained particles was measured in the same manner as in 2.(1) above, and it was found that α-Ga 2 O 3was identified as the main phase of the product. Evaluation was performed in the same manner as in 2.(2) to (4) above. The results are shown in Table 1. That is, the particle size and particle height were more than 100 μm, the surface roughness Ra of the particles was 100 nm or less, and the Raman shift was 690 cm -1 The half-width of the closest Raman peak is 20 cm -1 or less, and the atomic ratio of Ga / O was within the range of 0.70 to 1.00. Furthermore, as a result of observing the obtained particles by SEM, no holes were observed in the crystals.

[0035] [Table 1]

[0036] [Example 5] 1. Hydrothermal synthesis In the same manner as in Example 1, a 0.1 M aqueous solution of gallium nitrate octahydrate was prepared, and the pH was adjusted to 10.0 using a 1 M aqueous solution of KOH as a pH adjuster to obtain a raw material solution. As the pressure-resistant vessel 10 shown in FIG. 1, one made of Hastelloy (registered trademark) C276 was used, the pressure regulating valve 36 of the hydrothermal synthesis system 20 was set to 30.0 MPa, the maximum temperature was set to 410°C, and the holding time at the maximum temperature was set to 24 hours. Except for this, hydrothermal synthesis was performed under the same conditions as in Example 1. The weight of the obtained crystal was 0.042 g.

[0037] 2. Evaluation (1) The crystal phase, microstructure and composition, particle shape and surface roughness, and Raman peak half-width were evaluated in the same manner as in Example 1. The main phase of the product was α-Ga 2 O 3 Other results are shown in Table 2.

[0038] (2) XRC rocking curve half-width The obtained α-Ga was analyzed using an XRD device (D8-DISCOVER, manufactured by Bruker-AXS). 2 O 3 XRC measurements were performed on the (006) and (104) faces of the particles. Specifically, 2θ, ω, χ, and φ were adjusted to obtain α-Ga 2 O3 After aligning the axis so that the peak of the (006) plane or (104) plane appears, using a tube voltage of 40 kV, a tube current of 40 mA, and an anti-scattering slit of 3 mm, in the case of (006) plane measurement, the range of ω = 20.0 to 20.4°, in the case of (104) plane measurement, the range of ω = 16.5 to 17.5°, an ω step width of 0.001°, and a counting time of 0.5 seconds were used. Also, as the X-ray source, a CuKα ray was made into parallel monochromatic light using a Ge(022) asymmetric reflection monochromator. The obtained α-Ga 2 O 3 The full width at half maximum of the XRC profile of was determined by using XRD analysis software (manufactured by Bruker-AXS, "LEPTOS" Ver4.03) and performing peak search after smoothing the profile. The results are shown in Table 2.

[0039] (3) Content of alkali metal elements Using a secondary ion mass spectrometer (SIMS), the content of alkali metal elements (Li, Na, K) near the particle surface was analyzed. The conditions for this D-SIMS analysis were as follows. <D-SIMS analysis conditions> · Apparatus: IMS-7f manufactured by CAMECA · Primary ion species: O 2 + · Primary ion acceleration voltage: 8.0 kV The content of each alkali metal element was Ga 2 O 3 Using a standard sample, it was converted to the unit of "atoms / cm 3 ", a depth profile was created, and it was determined as the average value of the values at a depth of 1 μm to 2 μm from the surface. The results are shown in Table 2.

[0040] [Example 6] When preparing the raw material solution, except that 1M NaOH aqueous solution was used as the pH adjuster and the pH of 0.1M aqueous solution of gallium nitrate octahydrate was set to 9.2, hydrothermal synthesis was carried out in the same manner as in Example 5, and various evaluations were carried out in the same manner as in Example 5. The main phase of the obtained crystal is α-Ga 2 O 3The evaluation results are shown in Table 2.

[0041] [Example 7] In preparing the raw material solution, a 1M LiOH aqueous solution was used as a pH adjuster, and the pH of the 0.1M aqueous solution of gallium nitrate octahydrate was set to 10.5. Except for this, hydrothermal synthesis was performed in the same manner as in Example 5, and various evaluations were performed in the same manner as in Example 5. The main phase of the obtained crystal was α-Ga 2 O 3 The evaluation results are shown in Table 2.

[0042] [Example 8] Hydrothermal synthesis was carried out in the same manner as in Example 5, except that 0.325 g of gallium oxyhydroxide (manufactured by Kojundo Chemical Co., Ltd.) was added to the raw material solution of Example 5, and various evaluations were carried out in the same manner as in Example 5. The main phase of the obtained crystal was α-Ga 2 O 3 The weight of the obtained crystals was 0.31 g. The evaluation results are shown in Table 2.

[0043] As shown in Table 2, the α-Ga 2 O 3 The particle diameter and height are more than 100 μm, the surface roughness Ra is 100 nm or less, and the Raman shift is 690 cm -1 The half-width of the closest Raman peak is 20 cm -1 The Ga / O atomic ratio was within the range of 0.70 to 1.00. The particles were observed by SEM, and no holes were observed in the crystals. Furthermore, the half-widths of the XRC rocking curves of the (006) and (104) planes were both 300 arcsec or less, and the crystallinity was sufficiently high. Furthermore, the content of each alkali metal element was 1.2×10 15 ~1.0×10 18 atoms / cm 3 It was.

[0044] [Table 2]

[0045] In this specification, the use of "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower limit and upper limit.

[0046] This application claims priority from Japanese Patent Application No. 2020-170500, filed on October 8, 2020, and Japanese Patent Application No. 2021-075003, filed on April 27, 2021, the entire contents of which are incorporated herein by reference. [Industrial Applicability]

[0047] The gallium oxide single crystal particles of the present invention can be used, for example, as a semiconductor material. [Explanation of symbols]

[0048] 10 pressure vessel, 11 vessel body, 12 lid, 12a protrusion, 14 aqueous solution containing Ga ions, 20 hydrothermal synthesis system, 22 electric furnace housing, 24 heater, 26 thermocouple for measuring temperature inside the furnace, 28 thermocouple for pressure vessel, 30 piping, 30a one end, 30b other end, 32 pressure gauge, 34 safety valve, 36 pressure regulating valve, 40 cooling water tank.

Claims

1. α-Ga 2 O 3 Single crystal particles having a diameter and height exceeding 100 μm; The ratio of Ga atoms to O atoms is 0.72 to 0.92; Gallium oxide single crystal particles.

2. Raman shift 690 cm -1 The half-width of the closest Raman peak is 20 cm -1 Below is the Gallium oxide single crystal particles according to claim 1.

3. The surface roughness Ra of the crystal surface is 100 nm or less. The gallium oxide single crystal particle according to claim 1 or 2.

4. The X-ray rocking curve half width of at least one of the (006) plane and the (104) plane is 300 arcsec or less. The gallium oxide single crystal particle according to any one of claims 1 to 3.

5. The content of each alkali metal element is 1.2 × 10 15 ~1.0 x 10 18 atoms / cm 3 That is, The gallium oxide single crystal particle according to any one of claims 1 to 4.

6. By placing an aqueous solution containing Ga ions and an alkali metal element and having a pH of 9.0 to 11.0 in a supercritical state at a temperature of 390° C. or higher and a pressure of 22.1 MPa or higher, α-Ga ions having a diameter and height exceeding 100 μm are produced. 2 O 3 Obtaining single crystal particles, Method for producing single crystal particles of gallium oxide.

7. The aqueous solution to which gallium oxyhydroxide has been added is brought into a supercritical state at a temperature of 390° C. or higher and a pressure of 22.1 MPa or higher. A method for producing the gallium oxide single crystal particles according to claim 6.

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