AlN single crystal substrate and device

Abstract

Provided is an AlN single crystal substrate that is less likely to crack when processed (ground, polished, cut, etc.). In the AlN single crystal substrate, when the thermal conductivity (W / m・K) of the AlN single crystal substrate at 25°C is λ25, the thermal conductivity (W / m・K) of the AlN single crystal substrate at 200°C is λ200, the electrical resistivity (Ω・cm) of the AlN single crystal substrate at 25°C is ρ, the average value of the transmittance (%) at 640 to 660 nm in the transmission spectrum of the AlN single crystal substrate is T640-660, and the average value of the transmittance (%) at 260 to 280 nm in the transmission spectrum is T260-280, the relational expression 5 ≤ [(λ25-λ200) × log10ρ] / (T640-660-T260-280) ≤50 is satisfied.

Description

[Technical Field]

[0001] The present invention relates to an AlN single crystal substrate and a device including the AlN single crystal substrate. [Background technology]

[0002] In recent years, aluminum nitride (AlN) single crystals have been attracting attention as a base substrate for deep ultraviolet light-emitting devices that use AlN-based semiconductors. For example, AlN and AlGaN are used as AlN-based semiconductors. These AlN-based semiconductors have a direct transition band structure, making them suitable for light-emitting devices, and they can be applied to deep ultraviolet light-emitting diodes (LEDs) and laser diodes (LDs).

[0003] For example, Patent Document 1 (WO2015 / 108089A1) discloses an ultraviolet light-emitting diode having a layered structure in which a substrate having a light-emitting principal surface from which light is emitted, an n-type layer, an active layer, and a p-type layer are layered in this order. This document states that when manufacturing ultraviolet light sources such as ultraviolet light-emitting diodes, the AlN single crystal used in the substrate having the light-emitting principal surface is required to have high ultraviolet transmittance. Furthermore, Patent Document 2 (JP 2009-190965 A) discloses a method for growing AlN crystal, including the steps of preparing a layered substrate having a layer structure of base substrate / first layer / second layer and growing AlN crystal on the principal surface of the base substrate by vapor phase epitaxy, in which the first layer is made of a material that is less likely to sublime than the base substrate at the AlN crystal growth temperature, and the second layer is made of a material that has a higher thermal conductivity than the first layer. This document states that AlN crystals have attracted attention as substrate materials for semiconductor devices such as optical devices and electronic devices because they have high thermal conductivity and high electrical resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO2015 / 108089A1 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-190965 Summary of the Invention

[0005] As mentioned above, AlN single crystals are attracting attention for a variety of applications. However, AlN single crystal substrates such as those disclosed in Patent Documents 1 and 2 are prone to cracking when processed (grinding, polishing, cutting, etc.), resulting in a problem of reduced yield. Therefore, it is desirable to suppress the occurrence of cracks in AlN single crystal substrates when processing them.

[0006] The present inventors have now discovered that when an AlN single crystal substrate satisfies certain relational expressions regarding transmittance (for ultraviolet light and visible light), thermal conductivity, and electrical resistivity, cracks are less likely to occur when the substrate is processed (grinded, polished, cut, etc.).

[0007] Therefore, an object of the present invention is to provide an AlN single crystal substrate that is less likely to crack when processed (grinded, polished, cut, etc.).

[0008] According to one aspect of the present invention, there is provided an AlN single crystal substrate, wherein the thermal conductivity (W / m K) of the AlN single crystal substrate at 25°C is λ 25 , the thermal conductivity (W / m K) of the AlN single crystal substrate at 200°C is λ 200 ρ is the electrical resistivity (Ω·cm) of the AlN single crystal substrate at 25°C, and T is the average transmittance (%) in the transmission spectrum of the AlN single crystal substrate from 640 to 660 nm. 640-660 The average value of the transmittance (%) in the range of 260 to 280 nm in the transmission spectrum is T 260-280 When 5≦[(λ 25 -λ 200 )×log 10 ρ] / (T 640-660 -T 260-280 )≦50 An AlN single crystal substrate is provided that satisfies the following relational expression.

[0009] According to another aspect of the present invention, there is provided a device comprising the AlN single crystal substrate. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the configuration of a heat treatment apparatus used to produce AlN raw material powder. [Figure 2] FIG. 1 is a schematic cross-sectional view showing the configuration of a crystal growth apparatus used in a sublimation method. DETAILED DESCRIPTION OF THE INVENTION

[0011] AlN single crystal substrate The AlN single crystal substrate of the present invention satisfies the relational expression relating to transmittance, thermal conductivity, and electrical resistivity: 5≦[(λ 25 -λ 200 )×log 10 ρ] / (T 640-660 -T 260-280 )≦50. 25 is the thermal conductivity (W / m K) of the AlN single crystal substrate at 25°C, and λ 200 is the thermal conductivity (W / m·K) of the AlN single crystal substrate at 200°C. ρ is the electrical resistivity (Ω·cm) of the AlN single crystal substrate at 25°C. T 640-660 is the average transmittance (%) in the range of 640 to 660 nm in the transmission spectrum of the AlN single crystal substrate, and T 260-280 is the average value of the transmittance (%) in the transmission spectrum from 260 to 280 nm. In this way, when the AlN single crystal substrate satisfies the predetermined relationship between the transmittance (for ultraviolet and visible light), thermal conductivity, and electrical resistivity, cracks are less likely to occur when processed (grinding, polishing, cutting, etc.). Therefore, by processing such an AlN single crystal substrate, AlN single crystal substrates can be manufactured with a high yield. That is, as mentioned above, conventional AlN single crystal substrates have the problem of being prone to cracks when processed (grinding, polishing, cutting, etc.), resulting in a decrease in yield. In this regard, the AlN single crystal substrate of the present invention can advantageously solve the above problem.

[0012] Here, the "average transmittance" of a specific wavelength range in the transmission spectrum is determined by dividing the sum of the transmittance (%) of each wavelength (nm) measured in a specific wavelength range (e.g., 260-280 nm, 640-660 nm, etc.) by the number of measurement points. For example, if the transmittance is measured at 1 nm intervals in the 640-660 nm region and the sum of these transmittances is 1050, the average transmittance (e.g., 1050 / 21 = 50%) can be obtained by dividing the sum by 21, which is the number of measurement points. Furthermore, the transmittance at this time is the transmittance T when the thickness of the AlN single crystal substrate is converted to 100 μm. 100μm It is preferable to use a thickness of 1000 nm. This is because if there is variation in the thickness of the AlN single crystal substrate to be measured, the transmittance will also change accordingly. For example, if the AlN single crystal substrate is thick, the transmittance will be low, and if the AlN single crystal substrate is thin, the transmittance will be high.

[0013] The transmittance in the transmission spectrum can be calculated, for example, by the following calculation method: Total light transmittance T of the AlN single crystal substrate a is measured using a spectrophotometer. a The measured transmittance and the theoretical transmittance T of the AlN single crystal substrate t The absorption coefficient α of the AlN single crystal substrate is calculated using the formula: Then, the transmittance T when converted to a thickness of 100 μm of the AlN single crystal substrate is calculated using the formula: 100μm Calculate α and T 100μm is the following formula: α=-1 / t×ln(T a / T t ), and T 100μm =exp(-α / 100) (where t represents the actual thickness (cm) of the AlN single crystal sample). For AlN single crystal samples with low transmittance and for which it is difficult to calculate the absorption coefficient α, the actual thickness is reduced to obtain the total light transmittance T a In this way, the transmittance T when converted to a thickness of 100 μm is 100μm The transmission spectrum based on

[0014] In the transmission spectrum of the AlN single crystal substrate, the average transmittance (T 640-660 ) and the average transmittance (T 260-280 ) difference (T 640-660 -T 260-280 ) is preferably 10 to 80 percentage points (%pt), more preferably 20 to 75%pt, and even more preferably 30 to 70%pt.

[0015] The AlN single crystal substrate has a thermal conductivity (λ 25 ) and thermal conductivity (λ 200 ) difference (λ 25 -λ 200 ) is preferably 60 to 90 W / m·K, more preferably 65 to 85 W / m·K, and even more preferably 70 to 80 W / m·K.

[0016] The electrical resistivity ρ of the AlN single crystal substrate at 25°C is 1×10 3 ~1×10 17 Ω·cm is preferred, and 5×10 3 ~1×10 11 Ω·cm, more preferably 1×10 4 ~1×10 6 Ω·cm.

[0017] As mentioned above, the AlN single crystal substrate has a thickness of 5≦[(λ 25 -λ 200 )×log 10 ρ] / (T 640-660 -T 260-280 )≦50, but preferably 5≦[(λ 25 -λ 200 )×log 10 ρ] / (T 640-660 -T 260-280 )≦35, and more preferably 5≦[(λ 25 -λ 200 )×log 10 ρ] / (T 640-660 -T 260-280)≦20. By satisfying this relationship, an AlN single crystal substrate can be obtained that is less susceptible to cracks when processed (grinding, polishing, cutting, etc.). Furthermore, by processing such an AlN single crystal substrate, AlN single crystal substrates can be manufactured with a higher yield.

[0018] The AlN single crystal substrate of the present invention is preferably an oriented layer oriented in both the c-axis and a-axis directions, and may contain mosaic crystals. Mosaic crystals are a collection of crystals that do not have clear grain boundaries but whose orientation slightly differs from one or both of the c-axis and a-axis. Such an oriented layer has a structure in which the crystal orientation is generally aligned in the approximately normal direction (c-axis direction) and the in-plane direction (a-axis direction). This structure makes it possible to form a semiconductor layer thereon with excellent quality, particularly excellent orientation. In other words, when a semiconductor layer is formed on an oriented layer, the crystal orientation of the semiconductor layer generally follows the crystal orientation of the oriented layer. Therefore, it is easy to form a semiconductor film on an AlN single crystal substrate as an oriented film.

[0019] The method for evaluating the orientation of the AlN single crystal substrate of the present invention is not particularly limited, and known analytical techniques such as EBSD (Electron Backscatter Diffraction Patterns) and X-ray pole figures can be used. For example, when using EBSD, inverse pole figure mapping and crystal orientation mapping of the surface (plate surface) of the AlN single crystal substrate or a cross section perpendicular to the plate surface are measured. The obtained inverse pole figure mapping can be defined as being oriented along two axes, the approximately normal direction and the approximately plate surface direction, when the following four conditions are met: (A) the substrate is oriented in a specific direction (first axis) approximately normal to the plate surface; (B) the substrate is oriented in a specific direction (second axis) approximately in the plate surface and perpendicular to the first axis; and (C) the tilt angles from the first axis are distributed within ±10°; and (D) the tilt angles from the second axis are distributed within ±10°. In other words, when the above four conditions are met, the substrate can be determined to be oriented along two axes, the c-axis and the a-axis. For example, if the approximately normal direction to the plate surface is oriented along the c-axis, the approximately in-plane direction may be oriented along a specific direction (e.g., the a-axis) perpendicular to the c-axis. The AlN single crystal substrate may be oriented along two axes, the approximately normal direction and the approximately in-plane direction, but it is preferable that the approximately normal direction be oriented along the c-axis. The smaller the tilt angle distribution in the approximately normal direction and / or the approximately in-plane direction, the less mosaic the AlN single crystal substrate will have, and the closer it is to zero, the closer it will be to a perfect single crystal. Therefore, from the perspective of the crystallinity of the AlN single crystal substrate, it is preferable that the tilt angle distribution be small in both the approximately normal direction and the approximately in-plane direction; for example, ±5° or less is preferable, and ±3° or less is even more preferable.

[0020] The AlN single crystal substrate has one side preferably 20 cm 2 More than 70cm, preferably 2 More than 170cm, preferably 2 By increasing the area of ​​the AlN single crystal substrate in this way, it is possible to increase the area of ​​the semiconductor layer formed thereon. This makes it possible to obtain a large number of semiconductor elements from a single semiconductor layer, which is expected to reduce manufacturing costs. There is no particular upper limit on the size, but typically, it is 710 cm per side.2 The following is the result.

[0021] Manufacturing method The AlN single crystal substrate of the present invention can be manufactured by various methods as long as the aforementioned relationships between transmittance, thermal conductivity, and electrical resistivity are satisfied. A seed substrate may be prepared and epitaxially grown thereon, or an AlN single crystal substrate may be manufactured directly by spontaneous nucleation without using a seed substrate. The seed substrate used may be an AlN substrate to achieve homoepitaxial growth, or a different substrate may be used for heteroepitaxial growth. While vapor-phase deposition, liquid-phase deposition, or solid-phase deposition may be used to grow the single crystal, vapor-phase deposition is preferred, followed by grinding away the seed substrate as needed to obtain the desired AlN single crystal substrate. Examples of vapor-phase deposition methods include various CVD (chemical vapor deposition) methods (e.g., thermal CVD, plasma CVD, MOVPE, etc.), sputtering, hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE), sublimation, and pulsed laser deposition (PLD), with sublimation and HVPE being preferred. Examples of liquid-phase deposition methods include solution growth (e.g., flux deposition). It is also possible to obtain an AlN single crystal substrate without directly depositing an AlN single crystal on a seed substrate by forming an oriented precursor layer, converting the oriented precursor layer into an AlN single crystal layer by heat treatment, and polishing the seed substrate. Examples of methods for forming the oriented precursor layer include aerosol deposition (AD) and supersonic plasma particle deposition (HPPD).

[0022] Although known conditions can be used for any of the above-mentioned solid-phase deposition, vapor-phase deposition, and liquid-phase deposition methods, the following describes a method for producing an AlN single crystal substrate using, for example, sublimation deposition. Specifically, the substrate is produced by (a) heat-treating AlN polycrystalline powder, (b) depositing an AlN single crystal layer, and (c) grinding off the seed substrate and polishing the surface of the AlN single crystal layer.

[0023] (a) Heat treatment of AlN polycrystalline powder This process heat-treats AlN polycrystalline powder to obtain AlN raw material powder. As shown in FIG. 1, AlN powder 12, the raw material for AlN single crystal, is placed in sheath 10 and heat-treated in a N2 atmosphere. At this time, graphite powder 14 and metal oxide (Y2O3, CaO, CeO2, Yb2O3, Sm2O3, etc.) powder 15 are placed in separate crucibles 16 and 17 so as not to directly contact the AlN powder 12. These crucibles 16 and 17 are large enough to fit within sheath 10. By appropriately adjusting the contents of graphite and metal oxide, an AlN single crystal substrate satisfying the aforementioned relationship between transmittance, thermal conductivity, and electrical resistivity can be fabricated. The pressure inside the sheath 10 is preferably 0.1 to 10 atm, more preferably 0.5 to 5 atm. The heat treatment temperature is preferably 1900°C to 2300°C, more preferably 2000 to 2200°C. Preferred examples of materials for forming the sheath and the crucible include tantalum carbide, tungsten, molybdenum, and boron nitride (BN), and more preferred is BN.

[0024] (b) Deposition of an AlN single crystal layer This process is a process of forming an AlN single crystal film on a seed substrate in a crystal growth apparatus. An example of a crystal growth apparatus used in the sublimation method is shown in FIG. 2. The film formation apparatus 20 shown in FIG. 2 includes a crucible 22, a heat insulator 24 for insulating the crucible 22, and a coil 26 for heating the crucible 22 to a high temperature. The crucible 22 contains AlN raw material powder 28 in its lower part and includes a seed substrate 30 in its upper part on which a sublimate of the AlN raw material powder 28 is deposited. The interior of the crucible 22 is pressurized in an N2 atmosphere, and the crucible 22 is heated by the coil 26 to sublimate the AlN raw material powder 28. The pressure is preferably 10 to 100 kPa, and more preferably 20 to 90 kPa. At this time, a temperature gradient is created so that the temperature in the vicinity of the seed substrate 30 in the upper part of the crucible 22 is lower than the temperature in the vicinity of the AlN raw material powder 28 in the lower part of the crucible 22. For example, the portion of the crucible 22 near the AlN raw material powder 28 is preferably heated to 1900 to 2250°C, more preferably 2000 to 2200°C, and the portion of the crucible 22 near the seed substrate 30 is preferably heated to 1400 to 2150°C, more preferably 1500 to 2050°C. At this time, the temperature of the portion near the seed substrate 30 is preferably 100 to 500°C lower than the portion near the AlN raw material powder 28, more preferably 200 to 400°C. The heating is preferably maintained for 2 to 100 hours, more preferably 4 to 90 hours. Temperature control can be performed by measuring the temperatures of the upper and lower parts of the crucible 22 with radiation thermometers (not shown) through holes in the heat insulating material 24 covering the crucible 22 and feeding the measured temperatures back into the temperature control. In this way, a SiC single crystal is placed as the seed substrate 30, and AlN is re-precipitated on its surface to form an AlN single crystal layer 32.

[0025] (c) Grinding and removing the seed substrate and polishing the surface of the AlN single crystal layer This process includes a grinding step, which removes the seed substrate to expose the AlN single crystal layer, and a polishing step, which removes irregularities and defects on the AlN single crystal surface. Since the AlN single crystal layer fabricated using a SiC substrate as the seed substrate through steps (a) and (b) still contains residual SiC single crystals, a grinding process is performed to expose the surface of the AlN single crystal layer. Furthermore, to achieve a mirror finish on the surface of the AlN single crystal layer after deposition, the plate surface is smoothed by lapping using diamond abrasive grains, and then polished by chemical mechanical polishing (CMP) using colloidal silica or similar. In this way, an AlN single crystal substrate can be fabricated.

[0026] device Devices can also be fabricated using the AlN single crystal substrate of the present invention. That is, devices preferably equipped with an AlN single crystal substrate are provided. Examples of such devices include deep ultraviolet laser diodes, deep ultraviolet diodes, power electronic devices, high-frequency devices, heat sinks, etc. The method for fabricating devices using AlN single crystal substrates is not particularly limited, and they can be fabricated by known methods. [Example]

[0027] The present invention is further illustrated by the following examples.

[0028] Examples 1-12 (1) Preparation of AlN single crystal substrate (1a) Heat treatment of AlN polycrystalline powder As shown in FIG. 1 , commercially available AlN powder 12 with an average particle size of 1 μm, used as a raw material for AlN single crystals, was placed in BN sheath 10. Commercially available graphite powder 14 with an average particle size of 1 μm was placed in BN crucible 16 in the ratio shown in Table 1 relative to 100 parts by weight of the AlN powder, while metal oxide powder 15 was placed in BN crucible 17 in the ratio shown in Table 1 relative to 100 parts by weight of the AlN powder. Here, as metal oxide powder 15, yttrium oxide powder with an average particle size of 0.1 μm was used in Examples 1 to 6 and 10 to 12, cerium oxide powder with an average particle size of 1 μm in Example 7, ytterbium oxide powder with an average particle size of 1 μm in Example 8, and samarium oxide powder with an average particle size of 3 μm in Example 9 were used. These BN crucibles 16 and 17 were placed in BN sheath 10 so as not to directly contact AlN powder 12. The BN crucibles 16 and 17 were large enough to be housed within the sheath 10. The BN sheath 10 was heat-treated in a graphite heater furnace at 2200°C in an N2 atmosphere at 0.1 to 10 atmospheres. In this way, the AlN polycrystalline powder was heat-treated to produce AlN raw material powder.

[0029] (1b) Deposition of AlN single crystal layer 2, a crucible 22 was used as a crystal growth container, and a SiC substrate was placed in the crucible as a base material (seed substrate) 30. The AlN raw material powder 28 prepared in (1a) above was placed in the crucible so as not to come into contact with the SiC substrate. The crucible 22 was pressurized to 50 kPa in an N atmosphere, and the portion of the crucible 22 near the AlN raw material powder 28 was heated to 2100°C by high-frequency induction heating, while the portion of the crucible 22 near the SiC substrate 30 was heated to a lower temperature (temperature difference of 200°C) and maintained at that temperature, thereby re-precipitating an AlN single crystal layer 32 on the SiC substrate 30. The maintenance time was 10 hours.

[0030] (1c) Grinding and removal of SiC substrate and polishing of AlN single crystal layer surface The SiC substrate with re-precipitated AlN obtained in (1b) above was ground using a grinding wheel with a grit size up to #2000 until the AlN single crystal was exposed, and then the surface was further smoothed by lapping using diamond abrasive grains. The surface was then mirror-finished by chemical mechanical polishing (CMP) using colloidal silica. In this way, an AlN single crystal substrate was produced.

[0031] (2) Evaluation of AlN single crystal substrates (2a) EBSD measurement EBSD measurements were carried out on the front and back surfaces of the AlN single crystal substrate, and it was found that the AlN crystal was oriented in both the c-axis and a-axis directions.

[0032] (2b) Transmission spectrum For AlN single crystal substrates, the total light transmittance T including the wavelength range of 200 to 800 nm a was measured using a spectrophotometer (Hitachi High-Tech Science, UH4150). a The measured transmittance and the theoretical transmittance T of the AlN single crystal substrate t After calculating the absorption coefficient α of the AlN single crystal substrate using 100μm α and T 100μm is the following formula: α=-1 / t×ln(T a / T t ), and T 100μm =exp(-α / 100) (where t represents the actual thickness (cm) of the AlN single crystal sample) In this way, the transmittance T when converted to a thickness of 100 μm is 100μm Based on the obtained transmission spectrum, the average transmittance (%) in the range of 640 to 660 nm was calculated as T 640-660 The average transmittance (%) in the range of 260 to 280 nm is T 260-280 When 640-660 and T 260-280 The difference (T 640-660 -T 260-280 ) (%pt) was calculated. The results are shown in Table 1.

[0033] (2c) Thermal conductivity Thermal conductivity λ of AlN single crystal substrate at 25℃ and 200℃ 25 and λ 200was calculated using the formula: (thermal conductivity) = (thermal diffusivity) × (specific heat) × (density). The thermal diffusivity was measured at 25°C and 200°C by processing the AlN single crystal sample into a disk shape with a diameter of 10 mm and a thickness of 0.4 mm using a flash analyzer thermal diffusivity measuring device (NETSCH, LFA467HT). The specific heat was measured at 25°C and 200°C by processing the AlN single crystal sample into a disk shape with a diameter of 5 mm and a thickness of 0.4 mm using a differential scanning calorimeter (NETSCH, DSC404). The density was measured by the Archimedes method in accordance with JIS R 1634:1998. The thermal conductivity λ at 25°C was 25 and thermal conductivity λ at 200°C 200 The difference between (λ 25 -λ 200 ) (W / m K) was calculated. The results are shown in Table 1.

[0034] (2d) Electrical resistivity Ohmic electrodes were formed on the front and back surfaces of the AlN single crystal substrate, and the electrical resistivity was measured at 25° C. by the two-terminal method. The results are shown in Table 1.

[0035] (2e) Calculation of relational expressions Based on the values ​​obtained in (2b) to (2d) above, the relation: [(λ 25 -λ 200 )×log 10 ρ] / (T 640-660 -T 260-280 The values ​​obtained by the above procedure were calculated. The results are shown in Table 1.

[0036] (2f) Check for cracks The surfaces of the AlN single crystal substrates after grinding and polishing in (1c) above were observed under an optical microscope to check for the presence or absence of cracks with a maximum length of 50 μm or more. A total of 10 AlN single crystal substrates were produced using the same method as in (1) above, and the number of AlN single crystal substrates that had cracks was determined and ranked according to the evaluation criteria shown below. The results are shown in Table 1. <Evaluation criteria> - Evaluation A: 9 to 10 AlN single crystal substrates were crack-free - Evaluation B: 6 to 8 AlN single crystal substrates without cracks - Evaluation C: 3 to 5 AlN single crystal substrates without cracks - Rating D: Cracks were observed in all AlN single crystal substrates

[0037] [Table 1]

Claims

1. An AlN single crystal substrate, wherein the thermal conductivity (W / m·K) of the AlN single crystal substrate at 25° C. is λ ２５ , the thermal conductivity (W / m·K) of the AlN single crystal substrate at 200°C is λ ２００ ρ is the electrical resistivity (Ω cm) of the AlN single crystal substrate at 25° C., and T is the average value of the transmittance (%) in the transmission spectrum of the AlN single crystal substrate from 640 to 660 nm. ６４０－６６０ The average transmittance (%) in the transmission spectrum from 260 to 280 nm is T ２６０－２８０ When 5≦[(λ) ２５ -l ２００ )×aog １０ ρ] / (T ６４０－６６０ -D ２６０－２８０ )≦50 An AlN single crystal substrate that satisfies the following relational expression.

2. 5≦[(λ) ２５ -l ２００ )×aog １０ ρ] / (T ６４０－６６０ -D ２６０－２８０ )≦20 2. The AlN single crystal substrate according to claim 1, which satisfies the following relational expression:

3. T ６４０－６６０ and T ２６０－２８０ The difference between (T ６４０－６６０ -T ２６０－２８０ 3. The AlN single crystal substrate according to claim 1, wherein the % pt is 30 to 70 percentage points (%pt).

4. λ ２５ and λ ２００ The difference between (λ ２５ -λ ２００ 4. The AlN single crystal substrate according to claim 1, wherein the thermal conductivity is 70 to 80 W / m·K.

5. ρ is 1×10 ４ ~1 x 10 ６ The AlN single crystal substrate according to any one of claims 1 to 4, wherein the resistivity is Ω·cm.

6. A device comprising the AlN single crystal substrate according to any one of claims 1 to 5.

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