Gallium nitride material and method for manufacturing gallium nitride material

Abstract

The present application realizes a GaN device with high performance. The gallium nitride material of the present application has at least a gallium nitride layer, and when photoluminescence measurement is performed at room temperature, the ratio (I2 / I1) of the luminescence intensity I2 at a wavelength of +5 nm from the luminescence wavelength of near-band edge luminescence caused by the gallium nitride layer to the luminescence intensity I1 of the near-band edge luminescence is 1.0 or more.

Description

Technical Field

[0001] This invention relates to gallium nitride materials and methods for manufacturing gallium nitride materials. Background Technology

[0002] To achieve high-efficiency optoelectronic devices, the development of gallium nitride (GaN) devices is constantly being advanced.

[0003] For example, Patent Document 1 discloses a technique for obtaining a high-quality semiconductor laminate with a p-type layer. Additionally, for example, Non-Patent Document 1 quantifies the external and internal quantum efficiencies of n-type GaN using photoluminescence measurement.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2023-110417

[0007] Non-patent literature

[0008] Non-patent document 1: Switching of major nonradiative recombination centers (NRCs) from carbon impurities to intrinsic NRCs in GaN crystals, AppliedPhysics Letters, 3 June 2024 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] The purpose of this invention is to realize high-performance GaN devices.

[0011] Solution for solving the problem

[0012] According to one aspect of the present invention, a gallium nitride material is provided, wherein,

[0013] The gallium nitride material has at least a gallium nitride layer.

[0014] When photoluminescence measurements were performed at room temperature, the ratio (I2 / I1) of the luminescence intensity I2 at a wavelength of +5 nm of the near-band-edge emission caused by the gallium nitride layer to the luminescence intensity I1 of the near-band-edge emission was 1.0 or higher.

[0015] Furthermore, according to another aspect of the present invention, a method for manufacturing gallium nitride material is provided, wherein...

[0016] The method for manufacturing the gallium nitride material includes:

[0017] The process of housing a substrate in a hydride vapor phase growth apparatus;

[0018] The process of growing a gallium nitride layer over the substrate using the aforementioned hydride vapor phase growth apparatus; and

[0019] The process of rapidly cooling the grown gallium nitride layer.

[0020] In the process of growing the gallium nitride layer, the heating rate before reaching the growth temperature is set to 30°C / min or more, and in the process of rapidly cooling the gallium nitride layer, the cooling rate during rapid cooling is set to 30°C / min or more.

[0021] The effects of the invention

[0022] According to the present invention, high-performance GaN devices can be realized. Attached Figure Description

[0023] Figure 1 This is a schematic cross-sectional view illustrating an example of a gallium nitride material according to the first embodiment of the present invention.

[0024] Figure 2 This is a flowchart illustrating an example of a method for manufacturing gallium nitride material according to the first embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram of the hydride vapor phase growth apparatus according to the first embodiment of the present invention.

[0026] Figure 4 This is a graph showing the results of photoluminescence measurement according to an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures

[0028] 10 substrate

[0029] 20 Gallium nitride (GaN) layer

[0030] 100 Gallium nitride (GaN) material

[0031] 207 Heater

[0032] 208 base

[0033] 300 Cooling Section

[0034] 310 Growth Section

[0035] 320 water cooling jacket

[0036] S10 Preparation Process

[0037] S20 growth process

[0038] S30 rapid cooling process. Detailed Implementation

[0039] <Insights gained by the inventor>

[0040] First, the inventor's insights will be explained.

[0041] It is known that luminescence efficiency can be improved by reducing the carbon concentration in GaN crystals. However, as described in Non-Patent Document 1, when the carbon concentration falls below a specified value (e.g., 3.5 × 10⁻⁶), the luminescence efficiency is reduced. 14 cm -3 When the carbon concentration is reduced, the main reason hindering the luminous efficiency of GaN changes from carbon to point defects in the crystal. In other words, in order to further improve the luminous efficiency of GaN devices, in addition to reducing the carbon concentration, suppressing the generation of point defects is also important.

[0042] The inventors conducted in-depth research on the aforementioned problems. As a result, they discovered that in the GaN crystal growth method using a hydride vapor phase growth apparatus (HVPE apparatus), point defects can be suppressed by shortening the heating time during crystal growth and rapidly cooling the crystal after growth.

[0043] Furthermore, by performing photoluminescence measurements on GaN crystals with suppressed point defects, the inventors discovered a new phenomenon.

[0044] In photoluminescence measurements of GaN crystals, it is known that luminescence of the LO phonon replica, generated by the transfer of energy from excitons to LO phonons, is observed on the long-wavelength side, slightly longer than the near-band-edge emission (hereinafter also referred to as NBE emission). In this specification, the emission wavelength of the LO phonon replica is defined as the emission wavelength of NBE emission + 5 nm. Previously, it was considered that a portion of NBE emission contributed to the emission of the LO phonon replica; if the emission intensity of NBE emission is set as I1 and the emission intensity of the LO phonon replica is set as I2, then it is generally assumed that I1 > I2. It should be noted that in this specification, the emission intensity I1 of NBE emission refers to the maximum emission intensity within the range of 361~363 nm in photoluminescence measurements, and the emission wavelength at this point is defined as the emission wavelength of NBE emission.

[0045] However, in GaN crystals where point defects have been suppressed using the methods described above, the luminescence intensity I2 of the LO phonon companion line was found to be greater than the luminescence intensity I1 of the NBE luminescence. Conversely, GaN crystals with a LO phonon companion line luminescence intensity I2 greater than the NBE luminescence intensity I1 are high-purity crystals with suppressed point defects, and can be considered suitable for realizing high-performance GaN devices.

[0046] [Details of embodiments of the present invention]

[0047] Next, an embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to these illustrations, but is shown in the technical solution and is intended to include all modifications within the same meaning and scope as the technical solution.

[0048] <First Embodiment of the Invention>

[0049] (1) Gallium nitride material 100

[0050] First, the structure of the gallium nitride material 100 (GaN material 100) in this embodiment will be described. Figure 1 This is a schematic cross-sectional view showing an example of the GaN material 100 of this embodiment. The GaN material 100 is, for example, a disc-shaped laminate with a diameter of 50 mm or more, which is used in the manufacture of semiconductor devices (GaN devices). It should be noted that the upper limit of the diameter of the GaN material 100 is not particularly limited, for example, it is 200 mm or less.

[0051] like Figure 1 As shown, the GaN material 100 has, for example, a substrate 10 and a gallium nitride layer 20 (GaN layer 20) disposed on the substrate 10.

[0052] The substrate 10 is the substrate on which the GaN layer 20 is grown. Preferably, a single crystal of GaN is used as the substrate 10.

[0053] The orientation of the main surface of the substrate 10 (the surface on which the GaN layer 20 is grown) is, for example, the (0001) surface (+c surface). The GaN crystal constituting the substrate 10 may also have a specified offset angle (e.g., more than 0 degrees and less than 1.2 degrees) relative to the main surface of the substrate 10.

[0054] The thickness of the substrate 10 is not particularly limited, for example, it is 150 μm or more and 2000 μm or less.

[0055] The conductivity type of substrate 10 is not particularly limited; for example, it can be an n-type substrate doped with Si.

[0056] The GaN layer 20 is, for example, a single crystal of GaN disposed on top of the substrate 10. The GaN layer 20 has, for example, an n-type conductivity and contains almost no p-type impurities such as Mg. Specifically, the p-type impurity concentration of the GaN layer 20 is preferably 5 × 10⁻⁶. 14 cm -3 The effective carrier concentration is 1×10⁻⁶. 14 cm -3 Above and 1×10 17 cm -3 The following applies. When measuring the p-type impurity concentration of GaN layer 20, the Mg concentration can be measured, for example, by secondary ion mass analysis (SIMS). Furthermore, when measuring the effective carrier concentration of GaN layer 20, from the viewpoint of performing photoluminescence measurement (described later), non-destructive measurement methods such as mercury CV, electrochemical CV, and non-contact CV (corona-Kelvin probe) are preferred.

[0057] The thickness of the GaN layer 20 is not particularly limited, for example, it can be above 100nm and below 2000μm.

[0058] In addition, the C concentration of the preferred GaN layer 20 is less than 5 × 10⁻⁶. 15 cm -3 Fe concentration less than 1×10 15 cm -3 .

[0059] GaN layer 20 is a GaN crystal in which point defects are suppressed by the manufacturing method described later. However, since it is very difficult to directly observe and evaluate point defects in GaN layer 20, in this embodiment, point defects are evaluated by photoluminescence measurement.

[0060] When photoluminescence measurements were performed on the GaN material 100 of this embodiment at room temperature (e.g., 23°C), the ratio (I2 / I1) of the luminescence intensity I2 at the emission wavelength of the LO phonon companion line (emission wavelength of NBE emission + 5 nm) to the luminescence intensity I1 of the near-band edge emission (NBE emission) caused by the GaN layer 20 was 1.0 or higher. This means that the luminescence intensity I2 of the LO phonon companion line is greater than or equal to the luminescence intensity I1 of the NBE emission. Furthermore, such a GaN layer 20 is a high-purity crystal with suppressed point defects, and can be considered a crystal suitable for realizing high-performance GaN devices. It should be noted that the upper limit of I2 / I1 is not particularly limited, for example, it is 2.0 or lower.

[0061] Furthermore, when photoluminescence measurements were performed on the GaN material 100 of this embodiment at room temperature, the emission wavelength with the highest luminescence intensity caused by the GaN layer 20 was preferably 2 nm or more and 10 nm or less above the emission wavelength of NBE emission. In conventional GaN crystals, the emission wavelength with the highest luminescence intensity is almost the emission wavelength of NBE emission (or its vicinity). However, in the GaN material 100 of this embodiment, the emission wavelength with the highest luminescence intensity shifts to a longer wavelength side that is slightly longer than the emission wavelength of NBE emission. Specifically, the luminescence intensity is highest at (or near) the emission wavelength of the LO phonon companion line. Such a GaN layer 20 is a high-purity crystal with suppressed point defects, and can be considered a crystal suitable for realizing high-performance GaN devices.

[0062] Furthermore, when photoluminescence measurements were performed on the GaN material 100 of this embodiment at room temperature, the wavelength range representing the luminescence intensity I1 or higher of the NBE luminescence preferably existed continuously for at least 5 nm. As described above, in the GaN material 100 of this embodiment, the luminescence wavelength with the highest luminescence intensity shifts to a longer wavelength side slightly longer than the NBE luminescence wavelength. Therefore, the wavelength range representing the luminescence intensity I1 or higher of the NBE luminescence exists on the longer wavelength side slightly longer than the NBE luminescence wavelength. Moreover, when this wavelength range is 5 nm or higher, it indicates that point defects in the GaN layer 20 are further suppressed. It should be noted that the upper limit of this wavelength range is not particularly limited, for example, it is 20 nm or less.

[0063] It is known that in photoluminescence measurements of GaN crystals, the emission of a secondary LO phonon companion line (LO2 phonon companion line) is observed on the long wavelength side, which is longer than the emission wavelength of the LO phonon companion line. In this specification, the emission wavelength of the LO2 phonon companion line is defined as the emission wavelength of the NBE emission + 17 nm. Compared with conventional GaN crystals, the emission intensity I3 of the LO2 phonon companion line of the GaN material 100 of this embodiment is increased. For example, when photoluminescence measurements of the GaN material 100 of this embodiment are performed at room temperature, the ratio (I3 / I1) of the emission intensity I3 at the emission wavelength of the LO2 phonon companion line (the emission wavelength of the NBE emission + 17 nm) to the emission intensity I1 of the NBE emission is preferably 0.15 or more. This indicates that point defects in the GaN layer 20 are further suppressed. It should be noted that the upper limit of I3 / I1 is not particularly limited, for example, it is 0.50 or less.

[0064] (2) Method for manufacturing gallium nitride material 100

[0065] Next, the manufacturing method of the GaN material 100 in this embodiment will be described. Figure 2This is a flowchart illustrating an example of a method for manufacturing the GaN material 100 according to this embodiment. For example... Figure 2 As shown, the method for manufacturing GaN material 100 in this embodiment includes, for example, a preparation step S10, a growth step S20, and a quenching step S30.

[0066] (Preparation process S10)

[0067] The preparation process S10 is, for example, the process of preparing a hydride vapor phase growth apparatus (HVPE apparatus) and housing the substrate 10 in the reaction vessel (growth section 310 for growing GaN layer 20) within the HVPE apparatus. Figure 3 This is a schematic diagram of the HVPE device used in this embodiment. Figure 3 As shown, the HVPE apparatus of this embodiment includes a cooling section 300 for rapidly cooling the grown GaN layer 20. Other structures of the HVPE apparatus can use the known structures described in Patent Document 1, and therefore their description is omitted.

[0068] (Growth process S20)

[0069] The growth process S20 is, for example, a process in which a GaN layer 20 is grown on top of a substrate 10 using an HVPE apparatus. In this embodiment, an n-type GaN layer 20 doped with Si is grown.

[0070] In growth process S20, the heating rate before reaching the growth temperature of GaN layer 20 is set to 30°C / min or higher. For rapid heating, for example, in addition to heating the growth section 310 using the heater 207 typically found in HVPE apparatus, the base 208 holding the substrate 10 can be induction heated to locally heat the substrate 10. It should be noted that there is no particular upper limit to the heating rate before reaching the growth temperature of GaN layer 20; for example, it can be 100°C / min or lower.

[0071] (Rapid cooling process S30)

[0072] The quenching process S30 is, for example, a process that quenches the grown GaN layer 20 (GaN material 100). In the quenching process S30, the cooling rate during quenching is set to 30°C / min or more. In the growth process S20, the heating rate before reaching the growth temperature is set to 30°C / min or more for rapid heating, and in the quenching process S30, the cooling rate is set to 30°C / min or more for quenching, thereby suppressing the generation of point defects in the GaN layer 20.

[0073] In the rapid cooling process S30, it is preferable to move the substrate 10 (including the base 208) from the growth section 310 for growing the GaN layer 20 to the cooling section 300 for rapidly cooling the GaN layer 20. Furthermore, as... Figure 3 As shown, the growth section 310 and the cooling section 300 are preferably spatially separated. The cooling section 300 can be configured, for example, to be covered by a water-cooling jacket 320. With such a structure, heat from the growth section 310 is less likely to propagate to the cooling section 300, thus facilitating rapid cooling of the GaN layer 20 and further suppressing the generation of point defects.

[0074] Through the above processes, the GaN material 100 of this embodiment can be manufactured.

[0075] <Other embodiments of the present invention>

[0076] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments and various modifications can be made without departing from its spirit.

[0077] For example, in the above embodiment, the GaN material 100 with a GaN layer 20 disposed on the substrate 10 has been described, but the structure of the GaN material 100 is not limited to this, as long as it has at least a GaN layer 20. For example, the GaN material 100 may also be a GaN self-standing substrate composed only of the GaN layer 20. In addition, for example, the GaN material 100 may have other layers between the substrate 10 and the GaN layer 20, and other layers or films may be stacked (formed) on the GaN layer 20.

[0078] Furthermore, for example, in the above embodiment, the case where the GaN layer 20 is n-type was described, but the GaN layer 20 can also be a high-resistivity GaN doped with Fe or the like. In this case, the resistivity of the GaN layer 20 is preferably 10. 4 Ωcm or more, more preferably 10 7 Ωcm or more.

[0079]

Example

[0080] Next, embodiments of the present invention will be described. These embodiments are examples of the present invention, and the present invention is not limited to these embodiments.

[0081] (1) Manufacturing of GaN materials

[0082] <Sample 1>

[0083] First, prepare a GaN self-standing substrate as the substrate. The main surface of the substrate is oriented as the +c plane, with a diameter of 2 inches (50.8 mm) and a thickness of 500 μm.

[0084] Next, the substrate is housed in the growth section of the HVPE apparatus, and a Si-doped n-type GaN layer is grown on top of the substrate using the manufacturing method described in the above embodiment to produce GaN material (sample 1). The GaN layer has a thickness of 10 μm and an effective carrier concentration of 1.8 × 10⁻⁶. 15 cm -3 .

[0085] The following conditions were applied as growth conditions for Sample 1.

[0086] Heater 207 set temperature: 800℃

[0087] Base 208 set temperature: 1000℃

[0088] Processing pressure: 1 atmosphere

[0089] Partial pressure of GaCl gas: 1 kPa

[0090] Partial pressure of NH3 gas / Partial pressure of GaCl gas: 30

[0091] Partial pressure of H2 gas / Partial pressure of GaCl gas: 50

[0092] <Sample 2>

[0093] First, prepare the same substrate as when manufacturing sample 1.

[0094] Next, the substrate was housed in the growth section of a conventional HVPE apparatus without a cooling section, and a Si-doped n-type GaN layer was grown using a known method to fabricate GaN material (Sample 2). The heating rate before reaching the GaN layer growth temperature was less than 30°C / min. Furthermore, no quenching was performed after GaN layer growth; instead, cooling was carried out slowly within the growth section. The GaN layer thickness was 10 μm, and the effective carrier concentration was 2.1 × 10⁻⁶. 15 cm -3 .

[0095] <Sample 3>

[0096] First, prepare the same substrate as when manufacturing sample 1.

[0097] Next, a Si-doped n-type GaN layer was grown using the well-known metal-organic vapor deposition (MOCVD) method to fabricate GaN material (sample 3). The GaN layer had a thickness of 10 μm and an effective carrier concentration of 1.1 × 10⁻⁶. 15 cm -3 .

[0098] (2) Photoluminescence determination

[0099] Photoluminescence measurements were performed on the GaN layers of samples 1-3 at room temperature (23℃). The light source was a HeCd laser (λ=325nm) with an excitation intensity of 6.538 W / cm². 2 Express the results in Figure 3 middle.

[0100] like Figure 4 As shown, in samples 2 and 3, the luminescence intensity I1 of the NBE (luminescence wavelength of 363 nm in samples 1 and 2, and 362 nm in sample 3) is greater than the luminescence intensity I2 of the LO phonon companion line (LO1) (luminescence wavelength of 368 nm in samples 1 and 2, and 367 nm in sample 3). Conversely, in sample 1 manufactured by the method of the present invention, the luminescence intensity I2 of the LO phonon companion line is greater than the luminescence intensity I1 of the NBE. It should be noted that... Figure 4 The lines shown representing the emission wavelengths of NBE, LO1, and LO2 are based on the emission wavelengths of sample 1.

[0101] Specifically, the I2 / I1 ratio is 1.40 for sample 1, 0.83 for sample 2, and 0.61 for sample 3. Furthermore, when the emission intensity of the LO2 phonon companion line (LO2) is set to I3 (380 nm in samples 1 and 2, and 379 nm in sample 3), the I3 / I1 ratio is 0.17 for sample 1, 0.13 for sample 2, and 0.06 for sample 3. In other words, the I2 / I1 and I3 / I1 values ​​are larger for sample 1 compared to samples 2 and 3.

[0102] (3) Fabrication of GaN devices

[0103] GaN devices (PN junction diodes) were fabricated using GaN materials from samples 1 to 3. The on-resistance and failure rate of these devices were investigated. The results are shown in Table 1.

[0104] Table 1

[0105]

[0106] As shown in Table 1, compared with the devices in samples 2 and 3, the on-resistance of the device in sample 1 is significantly improved, and the failure rate is also improved.

[0107] Based on the above, it has been confirmed that GaN materials capable of producing LO phonon companion lines with luminescence intensity exceeding that of NBE luminescence can be manufactured using the method of the present invention. Furthermore, it has been confirmed that such GaN materials are suitable crystals for realizing high-performance GaN devices.

[0108] <Preferred embodiment of the present invention>

[0109] The preferred embodiments of the present invention are described below.

[0110] (Note 1)

[0111] A gallium nitride material is provided, wherein,

[0112] The gallium nitride material has at least a gallium nitride layer.

[0113] When photoluminescence measurements were performed at room temperature, the ratio (I2 / I1) of the luminescence intensity I2 at a wavelength of +5 nm of the near-band-edge emission caused by the gallium nitride layer to the luminescence intensity I1 of the near-band-edge emission was 1.0 or higher.

[0114] (Note 2)

[0115] Based on the gallium nitride materials described in Appendix 1,

[0116] The p-type impurity concentration of the gallium nitride layer is 5 × 10⁻⁶. 14 cm -3 The effective carrier concentration is 1×10⁻⁶. 17 cm -3 the following.

[0117] (Note 3)

[0118] Based on the gallium nitride materials described in Appendix 1,

[0119] When photoluminescence measurements were performed at room temperature, the wavelength at which the gallium nitride layer caused the maximum luminescence intensity was greater than +2 nm and less than +10 nm of the near-band edge emission wavelength.

[0120] (Note 4)

[0121] Based on the gallium nitride materials described in Appendix 1,

[0122] When photoluminescence measurement is performed at room temperature, it indicates that the wavelength range of the luminescence intensity above I1 is at least 5 nm.

[0123] (Note 5)

[0124] Based on the gallium nitride materials described in Appendix 1,

[0125] When photoluminescence measurements were performed at room temperature, the ratio (I3 / I1) of the luminescence intensity I3 at the near-band edge emission wavelength +17 nm was 0.15 or higher.

[0126] (Note 6)

[0127] Based on the gallium nitride materials described in Appendix 1,

[0128] The C concentration of the gallium nitride layer is less than 5 × 10⁻⁶. 15 cm -3 Fe concentration less than 1×10 15 cm -3 .

[0129] (Note 7)

[0130] Based on the gallium nitride materials described in any of Notes 1 to 6,

[0131] The diameter of the gallium nitride material is 50 mm or more.

[0132] (Postscript 8)

[0133] A method for manufacturing gallium nitride material is provided, wherein...

[0134] The method for manufacturing the gallium nitride material includes:

[0135] The process of housing a substrate in a hydride vapor phase growth apparatus;

[0136] The process of growing a gallium nitride layer over the substrate using the aforementioned hydride vapor phase growth apparatus; and

[0137] The process of rapidly cooling the grown gallium nitride layer.

[0138] In the process of growing the gallium nitride layer, the heating rate before reaching the growth temperature is set to 30°C / min or more, and in the process of rapidly cooling the gallium nitride layer, the cooling rate during rapid cooling is set to 30°C / min or more.

[0139] (Note 9)

[0140] Based on the gallium nitride material manufacturing method described in Appendix 8

[0141] In the process of rapidly cooling the gallium nitride layer, the substrate is moved from the growth section for growing the gallium nitride layer to the cooling section for rapidly cooling the gallium nitride layer, and the growth section and the cooling section are spatially separated.

Claims

1. A gallium nitride material, wherein, The gallium nitride material has at least a gallium nitride layer. When photoluminescence measurements were performed at room temperature, the ratio (I2 / I1) of the luminescence intensity I2 at a wavelength of +5 nm of the near-band-edge emission caused by the gallium nitride layer to the luminescence intensity I1 of the near-band-edge emission was 1.0 or higher.

2. The gallium nitride material according to claim 1, wherein, The p-type impurity concentration of the gallium nitride layer is 5 × 10⁻⁶. 14 cm -3 The effective carrier concentration is 1×10⁻⁶. 17 cm -3 the following.

3. The gallium nitride material according to claim 1, wherein, When photoluminescence measurements were performed at room temperature, the wavelength at which the gallium nitride layer caused the maximum luminescence intensity was greater than +2 nm and less than +10 nm of the near-band edge emission wavelength.

4. The gallium nitride material according to claim 1, wherein, When photoluminescence measurement is performed at room temperature, it indicates that the wavelength range of the luminescence intensity above I1 is at least 5 nm.

5. The gallium nitride material according to claim 1, wherein, When photoluminescence measurements were performed at room temperature, the ratio (I3 / I1) of the luminescence intensity I3 at the near-band edge emission wavelength +17 nm to the luminescence intensity I1 was 0.15 or higher.

6. The gallium nitride material according to claim 1, wherein, The C concentration of the gallium nitride layer is less than 5 × 10⁻⁶. 15 cm -3 Fe concentration less than 1×10 15 cm -3 .

7. The gallium nitride material according to any one of claims 1 to 6, wherein, The diameter of the gallium nitride material is 50 mm or more.

8. A method for manufacturing gallium nitride material, wherein, The method for manufacturing the gallium nitride material includes: The process of housing a substrate in a hydride vapor phase growth apparatus; The process of growing a gallium nitride layer over the substrate using the aforementioned hydride vapor phase growth apparatus; and The process of rapidly cooling the grown gallium nitride layer. In the process of growing the gallium nitride layer, the heating rate before reaching the growth temperature is set to 30°C / min or more, and in the process of rapidly cooling the gallium nitride layer, the cooling rate during rapid cooling is set to 30°C / min or more.

9. The method for manufacturing gallium nitride material according to claim 8, wherein, In the process of rapidly cooling the gallium nitride layer, the substrate is moved from the growth section for growing the gallium nitride layer to the cooling section for rapidly cooling the gallium nitride layer, and the growth section and the cooling section are spatially separated.

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