Nitride materials and diodes and transistors using the same

Abstract

[assignment] The purpose is to provide a nitride material doped with impurities in AlN, in particular a nitride material with an electrical resistivity of 1.0 Ω·cm or less, and diodes and transistors using the same. [Solution] It is represented by the chemical formula A1α1B1β1Al1-α1-β1N or the chemical formula A1α1B1β1Ga1-α1-β1N, wherein α1 and β1 satisfy the following formula (1), or represented by the chemical formula B2β2Al1-β2N or the chemical formula B2β2Ga1-β2N, wherein β2 satisfies the following formula (2), and B1 and B2 include monovalent ones. 0<α1 / β1<6·····(1) 0<β2<0.52·····(2) (0<α1<1, 0<β1<1, A1 is at least one of Mg and Zn, and B1 and B2 are at least one of Au, Ag and Cu)

Description

Technology Field

[0001] The present invention relates to nitride materials, particularly conductive nitride materials, and diodes and transistors using the same. Background Technology

[0002] Nitride semiconductor materials, represented by AlN, GaN, InN, BN, and mixtures thereof, are characterized by having large band gaps. Semiconductor materials with such large band gaps exhibit excellent performance at high temperatures and high voltages, and are considered suitable for high-power, high-frequency applications or use in high-temperature environments. In particular, AlN is considered a promising material due to its particularly large band gap.

[0003] As such semiconductor materials, multiple Al with different Ga concentrations are used. x Ga 1-x Composed of N layers, such that the lattice constant in the c-axis direction becomes large in the +c-axis direction, each Al x Ga 1-x It has been proposed to reduce the concentration x of Al in the N layer (see Patent Document 1).

[0004] In addition, similarly, as such a semiconductor material, a spatially varied chemical composition (mixing several percent to 30 percent of GaN with respect to AlN) has been proposed (see Non-Patent Literature 1).

[0005] In addition, controlling the p-type electrical conductivity of Mg-doped Al is reported to be a hopeless situation (see Non-Patent Literature 2). Prior art literature

[0006] Japanese Published Patent No. 2023-111945

[0007] Jun Suda, et al., Realization of Ideal Characteristics with Aluminum Nitride (AlN)-based Ultra-Wide Bandgap Semiconductor pn Junction, [online], December 14, 2023, PRTIMES, [Accessed February 18, 2024], Internet <https: / / prtimes.jp / main / html / rd / p / 000000109.000079452.html> Proceedings of the 84th Autumn Conference of the Society for Applied Physics, p. 22-B101-15, "On Mg Acceptor Binding Energy in AlN: Experiment", Kyoto University The problem to be solved

[0008] However, the semiconductor material disclosed in Patent Document 1 was designed to facilitate the injection of electrons into AlN, but it had the problem that it was not a p-type semiconductor material.

[0009] In addition, the semiconductor material disclosed in Non-Patent Literature 1 can be produced as a p-type semiconductor material by doping with impurities, but there was a problem in that electron donation to acceptors does not occur at room temperature because there is insufficient thermal energy, and thus it does not exhibit sufficient electrical conductivity of the p-type semiconductor material.

[0010] Taking into account the circumstances mentioned above, the present invention aims to provide a nitride material in which impurities are doped into AlN (aluminum nitride) or GaN (gallium nitride), in particular, a nitride material having low electrical resistivity (conductivity) and semiconductor properties, and diodes and transistors using the same.

[0011] In addition, International Publication No. 2020 / 170610 contains the Mg described below α1 Au β1 Al 1-α1-β1 Although N is disclosed, it is described as indicating insulating properties. Furthermore, the nitride material described in this publication was obtained by numerical calculation, and there was a problem regarding whether the valence (valence) of Au used in the calculation was correct. Although details will be described later, the nitride material (A1) according to the present inventionα1 B1 β1 Al 1-α1-β1 N, A1 α1 B1 β1 Ga 1-α1-β1 N, B2 β2 Al 1-β2 N or B2 β2 Ga 1-β2 B1 or B2 included in N) comprises at least one of the valence, and furthermore, as mentioned above, the nitride material according to the present invention has conductivity (e.g., electrical resistivity of 10 7 It has a value of Ω·cm or less. Therefore, the present invention is completely different from the invention described in International Publication No. 2020 / 170610. means of solving the problem

[0012] As a result of continuing research regarding the aforementioned problems, the inventor of the present invention discovered the following groundbreaking nitride material.

[0013] A first embodiment of the present invention for solving the above problem is formula A1 α1 B1 β1 Al 1-α1-β1 N or chemical formula A1 α1 B1 β1 Ga 1-α1-β1 Represented by N, α1, β1 satisfy the following equation (1), or formula B2 β2 Al 1-β2 N or chemical formula B2 β2 Ga 1-β2 There is a nitride material characterized by being denoted by N, β2 satisfying the following equation (2), and B1 and B2 including monovalent ones.

[0014] 0<α1+β1<1·····(1)

[0015] 0<β2<1·······(2)

[0016] (0<α1<1, 0<β1<1, A1 is at least one of Mg and Zn, and B1 and B2 are at least one of Au, Ag, and Cu)

[0017] Here, “monovalent” refers to a substance with a valence of 1. The valence of B1 can be detected, for example, by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XANES), TEM-EELS, etc.

[0018] According to this first form, it is possible to provide a nitride material having semiconductor properties that perform electrical conduction mainly by holes while having low electrical resistivity (such as being able to provide a diode that operates at high temperatures (e.g., 100°C or higher) or has a high dielectric breakdown electric field strength (e.g., 2 MV / cm or higher)).

[0019] A second embodiment of the present invention is a nitride material described in the first embodiment, characterized in that α1 and β1 satisfy the following equation (3), and β2 satisfies the following equation (4).

[0020] 0<α1 / β1<6·····(3)

[0021] 0<β2<0.52·····(4)

[0022] According to this second form, it is possible to provide a nitride material having semiconductor properties that perform electrical conduction mainly by holes while having a lower electrical resistivity (such as being able to provide a diode that operates at high temperatures (e.g., 100°C or higher) or has a high dielectric breakdown electric field strength (e.g., 2 MV / cm or higher)).

[0023] A third embodiment of the present invention is a nitride material described in the first embodiment, characterized in that monovalent B1 is contained in the largest amount compared to B1 of a non-monovalent valence, or monovalent B2 is contained in the largest amount compared to B2 of a non-monovalent valence.

[0024] According to this third form, it is possible to provide a nitride material having semiconductor properties while having a lower electrical resistivity.

[0025] A fourth embodiment of the present invention is a nitride material described in the first embodiment, characterized in that its crystal structure is a wurtzite-type crystal structure.

[0026] According to this fourth form, it is possible to provide a nitride material having semiconductor properties while having a lower electrical resistivity.

[0027] A fifth embodiment of the present invention is a nitride material described in the first embodiment, characterized in that α1 and β1 satisfy the following equations (5) and (6).

[0028] 1≤α1 / β1≤5·····(5)

[0029] 0<α1+β1≤0.3····(6)

[0030] According to this fifth form, it is possible to provide a nitride material having semiconductor properties while having a lower electrical resistivity.

[0031] The sixth embodiment of the present invention is a nitride material described in any one of the first to fifth embodiments, characterized by having an electrical resistivity of 10.0 Ω·cm or less.

[0032] According to this sixth form, a nitride material having higher semiconductor properties can be provided.

[0033] The seventh embodiment of the present invention is a nitride material described in any one of the first to fifth embodiments, characterized by having an electrical resistivity of 1.0 Ω·cm or less.

[0034] According to this seventh form, a nitride material having higher semiconductor properties can be provided.

[0035] The eighth embodiment of the present invention is a diode comprising a nitride material described in the first embodiment and an n-type semiconductor material joined to the nitride material.

[0036] According to this eighth embodiment, a diode having a high dielectric breakdown electric field strength (e.g., 2 MV / cm or more) can be provided.

[0037] A ninth embodiment of the present invention is a transistor characterized by being composed of two n-type semiconductor materials joined to a nitride material described in a first embodiment, or being composed of an n-type semiconductor material and two nitride materials described in a first embodiment joined to the n-type semiconductor materials.

[0038] Here, “n-type semiconductor material” refers to a semiconductor material in which electrical conduction occurs through free electrons with negative charges.

[0039] According to this ninth embodiment, a transistor having a high dielectric breakdown electric field strength (e.g., 2 MV / cm or more) can be provided.

[0040] In addition, the specification of Japanese patent application 2024-31899 is incorporated by reference as part of this specification. Brief explanation of the drawing

[0041] FIG. 1 is a table showing the composition and electrical resistivity of an embodiment of Embodiment 1. Figure 2 is a graph showing the measurement results of the X-ray diffraction (XRD) device of Examples 1-1 to 1-3. FIG. 3 is a diagram showing the relationship between binding energy and intensity of Examples 1 and 3 of Embodiment 1. Figure 4 shows Mg 0.050 Au 0.037 Al 0.913 N, Mg 0.073 Au 0.036 Al 0.891 N, Mg 0.101 Au 0.033 Al 0.866 N and Mg 0.388 Au 0.081 Al 0.531 This is a diagram showing the relationship between the binding energy and strength of N. Figure 5 shows Mg0.050 Au 0.037 Al 0.913 This is a diagram showing the relationship between the binding energy and strength of N. Figure 6 shows Mg calculated using VASP 0.0625 Au 0.0625 Al 0.875 This is a diagram showing the band gap of N. FIG. 7 is a schematic diagram of a diode fabricated using a nitride material according to Embodiment 1. Fig. 8 shows Mg 0.06 Cu 0.04 Al 0.90 This is a graph showing the relationship between voltage and current of a diode fabricated using N. Fig. 9 shows Zn 0.02 Ag 0.02 Al 0.96 This is a graph showing the relationship between voltage and current of a diode fabricated using N. FIG. 10 is a table showing the composition and electrical resistivity of an embodiment of Embodiment 2. FIG. 11 is Example 2-1 (Au 0.02 Al 0.98 N), Au 0.05 Al 0.95 N and Au 0.14 Al 0.86 This is a graph showing the measurement results of N's X-ray diffraction (XRD) device. Figure 12 is a diagram showing the relationship between the binding energy and strength of Example 2-1. Figure 13 is a diagram showing the relationship between the binding energy and strength of Example 2-2. Figure 14 shows Au calculated using VASP 0.0625 Al 0.9375 This is a diagram showing the band gap of N. Specific details for implementing the invention

[0042] Embodiments of the nitride material according to the present invention will be described below with reference to the attached drawings. Furthermore, the present invention is not limited to the following embodiments.

[0043] (Embodiment 1)

[0044] The nitride material of this embodiment is formula A1 α1 B1 β1 Al 1-α1-β1 N or A1 α1 B1 β1 Ga 1-α1-β1 It is denoted by N, and α1 and β1 satisfy the following equation (1).

[0045] 0<α1+β1<1·····(1)

[0046] (0<α1<1, 0<β1<1, A1 is at least one of Mg and Zn, and B1 is at least one of Au, Ag and Cu)

[0047] In addition, this nitride material contains B1, which has a valence of 1. Also, the valence of B1 can be detected by X-ray photoelectron spectroscopy (XPS), etc.

[0048] Nitride materials with this composition have an electrical resistivity of 1.47 × 10⁻⁶ -6 It has the properties of a semiconductor that is greater than Ω·cm and less than 10.0Ω·cm (i.e., has conductivity) and performs electrical conduction mainly by holes.

[0049] In addition, it is desirable that α1 and β1 satisfy the following equation (3).

[0050] 0<α1 / β1<6·····(3)

[0051] These nitride materials have lower electrical resistivity and possess high semiconductor properties.

[0052] In addition, among nitride materials of this composition, the electrical resistivity is 1.47 × 10⁻⁶ -6 It is desirable that it has a greater Ω·cm or greater and a lower Ω·cm or less, as it possesses higher semiconductor properties.

[0053] In addition, it is preferable that the crystal structure of the nitride material of the present embodiment is a wurtzite-type crystal structure. Having a wurtzite-type crystal structure has a lower electrical resistivity and possesses high semiconductor properties.

[0054] Here, B1 may include a valence other than monovalence (e.g., 0valence, 2valence, 3valence, etc.), but a nitride material is preferred in which the content of monovalence B1 is the highest compared to that of non-monality B1. A nitride material with this composition has a lower electrical resistivity and possesses higher semiconductor properties.

[0055] In addition, the ratio of α1 and β1 is not particularly limited, but it is more desirable to satisfy the following equations (5) and (6).

[0056] 1≤α1 / β1≤5·····(5)

[0057] 0<α1+β1≤0.3···(6)

[0058] Nitride materials satisfying these equations have lower electrical resistivity and particularly high semiconductor properties.

[0059] Next, a method for manufacturing the nitride materials mentioned above will be described. These nitride materials can be manufactured using general physical vapor deposition (PDV) methods (sputtering, molecular beam epitaxy (MBE), deposition, etc.) or chemical vapor deposition (CVD). Specifically, for example, they can be manufactured by simultaneously sputtering a target composed of B1 (Au, Ag, Cu), a target composed of A1 (Mg, Zn), and a target composed of aluminum (Al) or gallium (Ga) onto a substrate (e.g., a silicon (Si) substrate) under a nitrogen gas (N2) atmosphere or under a mixed atmosphere of nitrogen gas (N2) and argon gas (Ar) (gas pressure 1 Pa or less). Additionally, as a target, an alloy containing B1, A1, and Al or Ga in a predetermined ratio may be used.

[0060] (Example)

[0061] Using the following apparatus and sputtering target, multiple thin films of the nitride material according to the present embodiment with a thickness of 0.4 to 1.5 μm were fabricated on an n-type silicon substrate with a resistivity of 0.02 Ωcm.

[0062] Multi-direction simultaneous sputtering film deposition device (manufactured by Eiko Engineering Co.)

[0063] Au sputtering target material (concentration: 99.9%)

[0064] Ag sputtering target material (concentration: 99.9%)

[0065] Cu sputtering target material (concentration: 99.9%)

[0066] Mg sputtering target material (concentration: 99.99%)

[0067] Zn sputtering target material (concentration: 99.99%)

[0068] Sputtering target material of Al (concentration: 99.999%)

[0069] GaN sputtering target material (concentration: 99.99%)

[0070] Gas: Mixed gas of nitrogen (purity: 99.99995% or higher) and argon (purity: 99.9999% or higher) (mixing ratio 50:50)

[0071] Substrate heating temperature: 500℃

[0072] The tabular formation experiment sets the air pressure inside the sputter chamber to 10 -5 The procedure was performed after lowering the vacuum level to below Pa using a vacuum pump. Additionally, to avoid the incorporation of impurities such as oxygen, the target surface was cleaned immediately after mounting the target or immediately before each film deposition experiment.

[0073] And, the composition and electrical resistivity of each obtained nitride material are shown in FIG. 1. From this figure, it was found that the electrical resistivity of each nitride material is 1.0 Ω·cm or less.

[0074] In addition, the measurement results of the X-ray diffraction (XRD) device of Examples 1-1 to 1-3 are shown in FIG. 2. As can be seen from this figure, it was found that each nitride material of Examples 1-1 to 1-3 has a wurtzite-type crystal structure.

[0075] In addition, Figure 3 shows the relationship between bond energy and strength when the nitride materials of Examples 1-1 and 1-3 were measured by XPS (manufactured by Shimadzu / KRATOS, AXIS-165). Also, Mg 0.050 Au 0.037 Al 0.913 N (topmost), Mg 0.073 Au 0.036 Al 0.891 N (2nd from the top), Mg 0.101 Au 0.033 Al 0.866 N (3rd from the top) and Mg 0.388 Au 0.081 Al 0.531 For N (bottom), the results of measuring the valence of Mg using an X-ray diffraction (XRD) device are shown in Fig. 4, and Mg 0.050 Au 0.037 Al 0.913 The results of measuring the valence of Au in N are shown in Fig. 5. The peaks shown in these figures represent the binding energies of each element. Furthermore, from Figs. 3 and 4, it was found that the binding energy of Mg2p corresponds to that of Mg with a valence of 2 (+2). Similarly, from Figs. 3 and 5, it was found that the binding energy of Au4f corresponds to that of Au with a valence of 1 (+1). Therefore, the nitride materials of Examples 1-1 and 1-3, and Mg 0.050 Au 0.037 Al 0.913 N and Mg 0.101 Au 0.033 Al 0.866 The valence of Mg included in N is 2(+2), and the nitride materials of Examples 1-1 and 1-3, and Mg 0.050 Au 0.037 Al 0.913Au with a valence (valence) of N of 1 (+1) is Au (Au) with a valence of 0 0 I found out that it contains more than ).

[0076] <Band Gap>

[0077] By simulation, the nitride material (Mg 0.0625 Au 0.0625 Al 0.875 The band gap of N) was calculated. For this simulation, software called VASP (Vienna Ab initio Simulation Package) was used, which employs a calculation method called first-principles calculation. Here, first-principles calculation is a general term for electronic state calculation methods that do not use fitting parameters, and is a method that can calculate electronic states using only the atomic number and coordinates of each atom constituting a unit cell or molecule.

[0078] In the simulation of the present embodiment, a wurtzite-type crystal structure of a supercell consisting of 16 aluminum atoms and 16 nitrogen atoms, which is doubled in the a-axis, b-axis, and c-axis directions respectively, was used.

[0079] Calculations were performed using a wurtzite-type crystal structure in which one Al atom was replaced with a Mg atom and one Al atom was replaced with an Au atom in a unit cell consisting of 16 Al atoms and 16 N atoms. Then, for this wurtzite-type crystal structure model, first-principles calculations were performed by simultaneously moving the atomic coordinates, cell volume, and cell shape, and the electronic state of the stable structure was calculated.

[0080] The results are shown in Figure 6. In addition, “E-Ef” on the horizontal axis in this figure represents energy levels based on the Fermi energy (Ef). From these results, it can be seen that there are acceptor levels, which are Density of State (DOS) originating from impurities (Mg, Au), at energy levels slightly higher than the valence band of AlN.

[0081] Here, it is known that semiconductor materials, which conduct electricity primarily through holes, can have a DOS (acceptor level) derived from impurities (added elements) at an energy level slightly higher than the valence band. From this, nitride materials (Mg 0.0625 Au 0.0625 Al 0.875 It can be seen that N) has semiconductor properties.

[0082] <p-type semiconductor>

[0083] The nitride material according to the present embodiment is obtained by doping (adding) at least one of Mg and Zn and at least one of Au, Ag, and Cu to a base material of AlN or GaN. That is, at least one of the divalent elements Mg and Zn and at least one of the monovalent elements Au, Ag, and Cu are doped into Al or Ga, which are trivalent elements contained in the base material of AlN or GaN. As a result, holes are generated, so the nitride material according to the present embodiment becomes a p-type semiconductor.

[0084] In fact, a diode (100) having the structure shown in FIG. 7 was fabricated. This diode (100) has, from bottom to top, a lower electrode, an n-type Si film (120) with a film thickness of 635 μm, and a nitride material (Mg) according to the present embodiment with a film thickness of 0.8 μm to 1.5 μm. 0.06 Cu 0.04 Al 0.90 N or Zn 0.02 Ag 0.02 Al 0.96N) It ​​is composed of a thin film (130) and an Al thin film (140) with a thickness of 80 nm. In addition, the lower electrode is composed of an Au thin film (110) with a thickness of 30 nm and a Ti thin film (111) formed on the film with a thickness of 10 nm.

[0085] For these diodes, the relationship between voltage and current was measured using a KEYSIGHT B2985A Electrometer / High Resistance Meter. The results are shown in Figures 8 and 9. From Figure 8, it can be seen that this diode functions properly as a diode, and Mg 0.06 Cu 0.04 Al 0.90 It was found that N is a p-type semiconductor. Also, from Fig. 9, this diode functions properly as a diode, and Zn 0.02 Ag 0.02 Al 0.96 It was found that N is a p-type semiconductor.

[0086] (Embodiment 2)

[0087] The nitride material of this embodiment is formula B2 β2 Al 1-β2 N or chemical formula B2 β2 Ga 1-β2 It is denoted by N, and β2 satisfies the following equation (2).

[0088] 0<β2<1·····(2)

[0089] (B2 is at least one of Au, Ag, and Cu)

[0090] Nitride materials with this composition have an electrical resistivity of 1.47 × 10⁻⁶ -6 It possesses the properties of a semiconductor, having a resistivity of Ω·cm or greater and 10.0Ω·cm or less (i.e., possessing conductivity) while performing electrical conduction primarily by holes. Furthermore, among nitride materials with this configuration, the electrical resistivity is 1.47×10⁻⁶ -6 It is desirable that it has a greater Ω·cm or greater and a lower Ω·cm or less, as it possesses higher semiconductor properties.

[0091] In addition, it is desirable that β2 satisfies the following equation (4).

[0092] 0<β2<0.52·····(4)

[0093] Such nitride materials have lower electrical resistivity and possess high semiconductor properties. Additionally, a range of β2 of 0 < β2 < 0.2 is more desirable. Nitride materials with β2 in this range have even lower electrical resistivity and possess higher semiconductor properties.

[0094] In addition, the crystal structure of the nitride material of the present embodiment is preferably a wurtzite-type crystal structure. Having a wurtzite-type crystal structure has a lower electrical resistivity and possesses high semiconductor properties.

[0095] Here, B2 may include a valence other than monovalence (e.g., 0valence, 2valence, 3valence, etc.), but a nitride material is preferred in which the content of monovalence B2 is the highest compared to that of non-monality B2. A nitride material with this composition has a lower electrical resistivity and possesses higher semiconductor properties.

[0096] Next, a method for manufacturing the nitride materials mentioned above will be described. These nitride materials can be manufactured using general manufacturing methods such as sputtering or deposition. Specifically, for example, they can be manufactured by simultaneously sputtering a target composed of B2 (Au, Ag, Cu) and a target composed of aluminum (Al) or gallium (Ga) onto a substrate (e.g., a silicon (Si) substrate) under a nitrogen gas (N2) atmosphere or a mixed atmosphere of nitrogen gas (N2) and argon gas (Ar) (gas pressure 1 Pa or less). In addition, as a target, an alloy containing B2 and Al or Ga in a predetermined ratio may be used.

[0097] (Example)

[0098] Using the following apparatus and sputtering target, thin films of the nitride material according to the present embodiment with a thickness of 0.4 to 1.5 μm were each fabricated on an n-type silicon substrate with a resistivity of 0.02 Ωcm.

[0099] Multi-direction simultaneous sputtering film deposition device (manufactured by Eiko Engineering Co.)

[0100] Au sputtering target material (concentration: 99.9%)

[0101] Ag sputtering target material (concentration: 99.9%)

[0102] Cu sputtering target material (concentration: 99.9%)

[0103] Sputtering target material of Al (concentration: 99.999%)

[0104] GaN sputtering target material (concentration: 99.99%)

[0105] Gas: Mixed gas of nitrogen (purity: 99.99995% or higher) and argon (purity: 99.9999% or higher) (mixing ratio 50:50)

[0106] Substrate heating temperature: 500℃

[0107] The tabular formation experiment sets the air pressure inside the sputter chamber to 10 -5 The procedure was performed after lowering the vacuum level to below Pa using a vacuum pump. Additionally, to avoid the incorporation of impurities such as oxygen, the target surface was cleaned immediately after mounting the target or immediately before each film deposition experiment.

[0108] And, the composition and electrical resistivity of each obtained nitride material are shown in FIG. 10. From this figure, it was found that the electrical resistivity of each nitride material is 1.0 Ω·cm or less.

[0109] In addition, Example 2-1 (Au 0.02 Al 0.98 N), Au 0.05 Al 0.95 N and Au 0.14 Al 0.86The measurement results of the X-ray diffraction (XRD) device of N are shown in FIG. 11. As can be seen from this figure, Example 2-1, Au 0.05 Al 0.95 N and Au 0.14 Al 0.86 It was found that each nitride material of N has a wurtzite-type crystal structure.

[0110] In addition, the relationship between bond energy and strength when the nitride materials of Examples 2-1 and 2-2 were measured by XPS (manufactured by Shimadzu / KRATOS, AXIS-165) is shown in Figures 12 and 13, respectively.

[0111] From FIG. 12, it was found that the nitride material of Example 2-1 contains monovalent Au, and contains the most monovalent Au compared to Au of other valencies (0-valence Au).

[0112] In addition, from FIG. 13, it was found that the nitride material of Example 2-2 contains monovalent Ag, and contains the most monovalent Ag compared to Ag of other valencies (zero valence Ag).

[0113] <Band Gap>

[0114] By simulation, the nitride material (Au) according to the present embodiment 0.0625 Al 0.9375 The band gap of N) was calculated. For this simulation, software called VASP was used, as in Embodiment 1.

[0115] In the simulation of the present embodiment, a wurtzite-type crystal structure of a supercell consisting of 16 aluminum atoms and 16 nitrogen atoms, which is doubled in the a-axis, b-axis, and c-axis directions respectively, was used in the simulation.

[0116] Calculations were performed using a wurtzite-type crystal structure in which one Al atom in a unit cell consisting of 16 Al atoms and 16 N atoms was replaced with an Au atom. Then, for this wurtzite-type crystal structure model, first-principles calculations were performed by simultaneously moving the atomic coordinates, cell volume, and cell shape, and the electronic state of the stable structure was calculated.

[0117] The results are shown in Fig. 14. Also, “E-Ef” on the horizontal axis in this figure represents energy levels based on the Fermi energy (Ef). From these results, it can be seen that there is an acceptor level, which is a DOS originating from the impurity (Au), at an energy level slightly higher than the valence band of AlN.

[0118] Here, as mentioned above, it is known that semiconductor materials can have a DOS (acceptor level) derived from impurities (added elements) at an energy level slightly higher than the valence band. From this, nitride materials (Au 0.0625 Al 0.9375 It can be seen that N) has semiconductor properties.

[0119] In addition, the nitride material according to the present embodiment is obtained by doping (adding) at least one of Au, Ag, and Cu to a base material, AlN or GaN. That is, at least one of the monovalent elements Au, Ag, and Cu is doped into Al or Ga, which are trivalent elements contained in the base material, AlN or GaN. As a result, holes are generated, so the nitride material according to the present embodiment becomes a p-type semiconductor.

[0120] (Other embodiments)

[0121] In Embodiment 1 mentioned above, Mg or Zn was used as A1, but the present invention is not limited thereto. For example, a nitride material may be configured to include Mg and Zn as A1 in a predetermined ratio. Even if a nitride material is configured in this way, the same effect as in Embodiment 1 can be obtained.

[0122] Likewise, in Embodiment 1 or 2, Au, Ag, or Cu were used as B1 and B2, but the present invention is not limited thereto. For example, the nitride material may be configured to include two of Au, Ag, and Cu in a predetermined ratio as B1 or B2, or the nitride material may be configured to include Au, Ag, and Cu in a predetermined ratio. Even if the nitride material is configured in this way, the same effect as in Embodiment 1 can be obtained.

[0123] In addition, a diode may be constructed using the nitride material according to the present invention. If the diode is made using the nitride material according to the present invention, its configuration is not particularly limited, and known configurations may be used. As for the configuration of the diode, for example, it may be composed of the nitride material according to the present invention and an n-type semiconductor material (a semiconductor material in which electrical conduction occurs by free electrons having a negative charge) joined to the nitride material. A diode with such a configuration has a high dielectric breakdown electric field strength (e.g., 2 MV / cm or more) compared to a diode using a semiconductor material using Si. In addition, as the n-type semiconductor material, for example, n-type GaN, n-type AlGaN, n-type SiGaN, etc., which have a high dielectric breakdown electric field strength (e.g., 2 MV / cm or more) may be used.

[0124] In addition, a transistor may be constructed using the nitride material according to the present invention. If the transistor utilizes the nitride material according to the present invention, its configuration is not particularly limited, and known configurations may be used. As for the configuration of the transistor, for example, it may be composed of the nitride material according to the present invention and two n-type semiconductor materials (semiconductor materials in which electrical conduction occurs by free electrons having a negative charge) joined via the nitride material, or composed of an n-type semiconductor material and two nitride materials according to the present invention joined via the n-type semiconductor material. A transistor with such a configuration has a high dielectric breakdown electric field strength (e.g., 2 MV / cm or more) compared to a transistor utilizing a p-type semiconductor material utilizing Si. Furthermore, as the n-type semiconductor material, for example, n-type GaN, n-type AlGaN, n-type SiGaN, etc., which have a high dielectric breakdown electric field strength (e.g., 2 MV / cm or more) may be used.

Claims

Claim 1 Chemical formula A1 α1 B1 β1 Al 1-α1-β1 N or chemical formula A1 α1 B1 β1 Ga 1-α1-β1 Represented by N, α1, β1 satisfy the following equation (1), or chemical formula B2 β2 Al 1-β2 N or chemical formula B2 β2 Ga 1-β2 A nitride material characterized by being denoted by N, wherein β2 satisfies the following equation (2), and B1 and B2 include monovalent ones. 0<α1+β1<1·····(1) 0<β2<1·······(2) (0<α1<1, 0<β1<1, A1 is at least one of Mg and Zn, and B1 and B2 are at least one of Au, Ag, and Cu) Claim 2 A nitride material according to claim 1, wherein α1 and β1 satisfy the following equation (3), and β2 satisfies the following equation (4). 0<α1 / β1<6·····(3) 0<β2<0.52····· (4) Claim 3 A nitride material according to claim 1, characterized in that monovalent B1 is contained in the largest amount compared to B1 of a non-monovalent valence, or monovalent B2 is contained in the largest amount compared to B2 of a non-monovalent valence. Claim 4 A nitride material according to claim 1, characterized in that its crystal structure is a wurtzite-type crystal structure. Claim 5 A nitride material according to claim 1, characterized in that the above α1 and the above β1 satisfy the following equations (5) and (6). 1≤α1 / β1≤5·····(5) 0<α1+β1≤0.3····(6) Claim 6 A nitride material characterized by having an electrical resistivity of 10.0 Ω·cm or less in any one of claims 1 to 5. Claim 7 A nitride material characterized by having an electrical resistivity of 1.0 Ω·cm or less in any one of claims 1 to 5. Claim 8 A diode comprising a nitride material described in claim 1 and an n-type semiconductor material joined to said nitride material. Claim 9 A transistor characterized by being composed of a nitride material described in claim 1 and two n-type semiconductor materials joined to said nitride material, or composed of an n-type semiconductor material and two nitride materials described in claim 1 joined to said n-type semiconductor materials.

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