Crystal film, laminate structure, semiconductor device, electronic apparatus, and system

Abstract

To provide a crystal film having excellent crystalline properties useful for a semiconductor device or the like, and a laminate structure.SOLUTION: A laminate structure is configured such that a crystal film is laminated directly or via another layer on a crystal substrate. The crystal film is a crystal film including, as a main component, metal oxide including germanium. The area of the crystal film is 100 μm2 or more. The film thickness is 1 μm or more. The crystal film has a crystal structure of tetragonal. For example, a laminate structure including a crystal film being a single crystal film is used for an application of a semiconductor device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a crystal film and a laminated structure useful for a semiconductor device. [Background technology]

[0002] Conventionally, Ga 2 O 3 is attracting attention as a promising ultra-wide bandgap (UWBG) semiconductor for future power electronics devices.

[0003] However, Ga 2 O 3 However, there was a problem in that p-type semiconductors were difficult to fabricate, and it was not easy to make them inexpensively, so there were still many challenges to overcome before they could be widely adopted. In recent years, rutile germanium dioxide (r-GeO) has been developed as a new UWBG semiconductor with a band gap of 4.44-4.68 eV. 2 ) is being researched, and rutile germanium dioxide can be used as n-type and p-type semiconductors and can be produced inexpensively, so Ga 2 O 3 It is expected to be a UWBG semiconductor to replace r-TiO. 2 r-GeO on (001) substrate 2 A laminated structure in which crystal films are laminated has been studied (Non-Patent Document 1, Patent Document 1). However, Non-Patent Document 2 was submitted as an erratum after Non-Patent Document 1 was peer-reviewed (Non-Patent Document 2), and it was found that the crystal grains (abnormal grains) described in Non-Patent Document 1 and Patent Document 1 were rutile-type germanium dioxide crystals, and the other parts were amorphous phase. In other words, the amorphous phase was formed in most parts, and even if a crystalline phase was formed, the crystal grains were formed only in a part. Therefore, a method for manufacturing a large-area crystal on a substrate surface was eagerly awaited. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Takane, K. Kaneko, “Establishment of a growth route of crystallized rutile GeO2 thin film (≧ 1 mm / h) and its structural properties” Applied Physics Letters Vol.119, pp.062104(1-6) (2021). [Non-Patent Document 2] Takane, K. Kaneko, Erratum: “Establishment of a growth route of crystallized rutile GeO2 thin film (≧1 μm / h) and its structural properties” Applied Physics Letters Vol.120, 099903(1-3) (2022). [Patent documents]

[0005] [Patent Document 1] International Publication No. 2023 / 008454 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a crystal film and a layered structure having excellent crystallinity that are useful for semiconductor devices and the like. [Means for solving the problem]

[0007] As a result of intensive research to achieve the above object, the present inventors have discovered a crystal film containing a metal oxide containing germanium as a main component, the crystal film having an area of ​​100 μm 2As described above, the inventors have succeeded in creating a crystalline film having a thickness of 1 μm or more, and have found that the obtained crystalline film has excellent crystallinity and is useful for semiconductor devices and the like. They have also found that such a crystalline film can solve the above-mentioned conventional problems in one fell swoop. Furthermore, after obtaining the above findings, the present inventors conducted further studies and completed the present invention.

[0008] That is, the present invention relates to the following inventions. [1] A crystal film containing a metal oxide containing germanium as a main component, the crystal film having an area of ​​100 μm 2 The crystal film is characterized in that the thickness of the crystal film is 1 μm or more. [2] The crystal film according to [1] above, wherein the crystal film has a tetragonal crystal structure. [3] The crystal film according to [1] above, which is a single crystal film. [4] A laminated structure in which a crystal film is laminated directly or via another layer on a crystal substrate, the crystal film being the crystal film described in [1] above. [5] The laminated structure according to [4], wherein the crystal substrate has a tetragonal crystal structure. [6] A semiconductor device including a crystal film or a laminated structure, wherein the crystal film is the crystal film described in [1] above, and the laminated structure is the laminated structure described in [4] above. [7] The semiconductor device according to [6] above, which is a power device. [8] The semiconductor device according to [6], which is a Schottky barrier diode (SBD), a junction barrier Schottky diode (JBS), a high electron mobility transistor (HEMT), a metal oxide semiconductor field effect transistor (MOSFET), a junction field effect transistor (JFET), an insulated gate bipolar transistor (IGBT) or a light emitting diode (LED). [9] An electronic device including a semiconductor device, characterized in that the semiconductor device is the semiconductor device described in [6] above.

[10] A system including an electronic device, characterized in that the electronic device is the electronic device described in [6] above. Effect of the Invention

[0009] The crystal film and layered structure of the present invention are useful for semiconductor devices and the like, and exhibit excellent crystallinity. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an example of a film-forming apparatus that can be suitably used in the present invention. [Diagram 2] FIG. 2 is a diagram showing the results of XRD analysis in Example 1. [Diagram 3] FIG. 2 is a diagram showing an SEM image in Example 1. [Figure 4] FIG. 2 is a diagram showing an EDS image in Example 1. [Diagram 5] FIG. 2 is a diagram showing the results of XRD analysis in Comparative Example 1. [Figure 6] FIG. 1 is a diagram showing an SEM image in Comparative Example 1. [Figure 7] FIG. 1 is a diagram showing an EDS image in Comparative Example 1. [Figure 8] FIG. 1 is a diagram illustrating a preferred example of a Schottky barrier diode (SBD) according to the present invention. [Figure 9] 1 is a diagram illustrating a preferred example of a high electron mobility transistor (HEMT) of the present invention. [Figure 10] FIG. 1 is a diagram showing a schematic diagram of a preferred example of a metal oxide semiconductor field effect transistor (MOSFET) of the present invention. [Figure 11] FIG. 1 is a diagram illustrating a preferred example of a junction field effect transistor (JFET) of the present invention. [Figure 12] 1 is a diagram illustrating a preferred example of an insulated gate bipolar transistor (IGBT) according to the present invention; [Figure 13] FIG. 1 is a diagram showing a schematic diagram of a preferred example of a light-emitting element (LED) of the present invention. [Figure 14]FIG. 1 is a diagram illustrating a preferred example of a junction barrier Schottky diode (JBS) of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The crystal film of the present invention is a crystal film containing a metal oxide containing germanium as a main component, and the area of ​​the crystal film is 100 μm 2 The thickness of the crystalline film is preferably 1 μm or more. In the present invention, the crystalline film preferably has a tetragonal crystal structure. According to this preferred range, the semiconductor characteristics can be improved. Furthermore, the crystalline film is preferably a single crystal film. According to this preferred range, the semiconductor characteristics can be improved, the breakdown voltage can be improved, and the semiconductor device can be manufactured with greater industrial advantages.

[0012] The laminated structure of the present invention is characterized in that the crystal film is laminated on a crystal substrate via another layer. In addition, in the laminated structure of the present invention, the crystal substrate preferably has a tetragonal crystal structure. According to such a preferred range, the semiconductor characteristics can be improved, and the crystallinity can be improved. The term "oriented" means a state in which a crystal plane represented by, for example, a (111) plane is aligned in a specific direction. In this specification, "film" can be read as "layer". The "laminated structure" is a structure including one or more crystal layers, and may include a layer other than a crystal layer (e.g., an amorphous layer). The crystal layer is preferably a single crystal layer, but may be a polycrystalline layer. In this specification, the orientation state can be confirmed by X-ray diffraction. More specifically, for example, when the crystal film is oriented in the (111) plane, it can be determined that the crystal film is oriented in the (111) plane when the integrated intensity ratio of the peak derived from the (111) plane to the peak derived from other crystal planes is larger than the integrated intensity ratio of the peak derived from the (111) plane to the peak derived from other crystal planes of the same randomly oriented crystal.

[0013] The term "main component" in the present invention means that the content of the metal oxide containing germanium in the crystal film is 50% or more in terms of the composition ratio in the crystal film. In an embodiment of the present invention, the content of the metal oxide containing germanium in the crystal film is preferably 70% or more, more preferably 90% or more in terms of the composition ratio in the crystal film. The crystal film may also contain other metals than germanium. Examples of the other metals include metals in Group 14 of the periodic table other than germanium (such as tin or silicon) and metals in Group 4 of the periodic table (such as titanium, zirconia or hafnium). The atomic ratio of germanium in the metal elements in the crystal film is preferably 0.5 or more. By setting the atomic ratio of germanium in such a preferred range, a crystal film having better semiconductor properties can be realized.

[0014] In the present invention, the area of ​​the crystal film is 100 μm 2 It is preferable that the area is 100 mm or more. 2 It is more preferable that the crystal film has an area of ​​1 μm or more. In the present invention, it is preferable that the crystal film is a single crystal film. Also, it is preferable that the thickness of the crystal film is 1 μm or more. According to these preferable ranges, the withstand voltage of the semiconductor film can be improved.

[0015] The above-mentioned preferable crystal film and laminated structure may be formed using a known film forming apparatus such as a mist CVD film forming apparatus.

[0016] The crystal substrate is not particularly limited as long as it does not impede the object of the present invention, and may be a known substrate. It may be an insulating substrate, a conductive substrate, a semiconductor substrate, a single crystal substrate, or a polycrystalline substrate. The crystal substrate may be a substrate having a metal film on its surface. In addition, when the crystal substrate is a conductive substrate, a vertical device can be fabricated without removing the substrate. The crystal structure of the crystal substrate is also not particularly limited as long as it does not impede the object of the present invention. Examples of the crystal structure of the crystal substrate include a hexagonal crystal structure, a cubic crystal structure, and a tetragonal crystal structure. Examples of the crystal substrate having a hexagonal crystal structure include a GaN substrate, a SiC substrate, or a sapphire substrate (such as an a-plane sapphire, a c-plane sapphire, an m-plane sapphire, and an r-plane sapphire substrate). Examples of the crystal substrate having a tetragonal crystal structure include GeO 2 Substrate, SrTiO 3 Substrate, TiO 2 Substrate or MgF 2 Examples of the crystal substrate having a cubic crystal structure include a Si substrate and a SiC substrate. The crystal substrate may have an off-angle, specifically, an off-angle of 0.1° to 10°.

[0017] In the present invention, a film may be formed directly on the substrate, or other layers such as a layer different from the oxide semiconductor (e.g., an n-type semiconductor layer, an n+ type semiconductor layer, an n- type semiconductor layer, etc.), an insulator layer (including a semi-insulator layer), a buffer layer, etc. may be laminated on the substrate, and then the film may be formed on the substrate via the other layers. In particular, a buffer layer can be suitably used to reduce the difference in lattice constant between the crystal substrate and the oxide crystal. Examples of materials constituting the buffer layer include SnO 2 , TiO 2 , V.O. 2 ,MnO 2 , RuO 2 , CsO 2 , IrO 2 , GeO 2 , CuO 2 , PbO 2 , AgO 2 , CrO2 , SiO 2 , SiC, GaN and mixed crystals thereof.

[0018] It is also possible to appropriately perform doping using the film forming apparatus. The doped crystal can be suitably used as a semiconductor film or semiconductor layer, and n-type or p-type dopants can be applied to conventional doping means in oxide semiconductors. Examples of the n-type dopant include antimony (Sb), arsenic (As), bismuth (Bi), phosphorus (P), fluorine (F), niobium (Nb), vanadium (V), tantalum (Ta), or tungsten (W). Examples of the p-type dopant include aluminum (Al), gallium (Ga), or indium (In). In the present invention, the laminated structure thus obtained is also included in the present invention.

[0019] The crystal film or the laminated structure is used as it is or after a known processing means such as peeling off of the substrate is applied, for example, by using a known means for a semiconductor device. Examples of the semiconductor device include a Schottky barrier diode (SBD), a junction barrier Schottky diode (JBS), a high electron mobility transistor (HEMT), a metal oxide semiconductor field effect transistor (MOSFET), a junction field effect transistor (JFET), an insulated gate bipolar transistor (IGBT), or a light emitting diode (LED). The semiconductor device may be a module equipped with the semiconductor device, or an electronic device and its parts equipped with the semiconductor device, and is useful for various applications, and is preferably applied to a power device in particular. The semiconductor device can be classified into a horizontal element (horizontal device) in which an electrode is formed on one side of the semiconductor layer, and a vertical element (vertical device) in which an electrode is formed on both the front and back sides of the semiconductor layer, and in the present invention, the semiconductor device can be suitably used for both a horizontal device and a vertical device.

[0020] Examples of semiconductor devices preferably used in the present invention will be described in more detail below with reference to the drawings, but the present invention is not limited to these examples. 2 A preferred example in which a crystal layer containing the above as a main component is used as a semiconductor layer will be described below.

[0021] 8 shows a preferred example of a Schottky barrier diode (SBD) including an n-type semiconductor layer 101a, an n+ type semiconductor layer 101b, a p-type semiconductor layer 102, a metal layer 103, an insulator layer 104, a Schottky electrode 105a, and an ohmic electrode 105b. The metal layer 103 is made of a metal such as Al, and covers the Schottky electrode 105a.

[0022] FIG. 9 shows a preferred example of a high electron mobility transistor (HEMT) including an n-type semiconductor layer 121a having a wide bandgap, an n-type semiconductor layer 121b having a narrow bandgap, an n+-type semiconductor layer 121c, a p-type semiconductor layer 123, a gate electrode 125a, a source electrode 125b, a drain electrode 125c, and a substrate 129.

[0023] 10 shows a preferred example of a metal oxide semiconductor field effect transistor (MOSFET) including an n-type semiconductor layer 131a, a first n+ type semiconductor layer 131b, a second n+ type semiconductor layer 131c, a p-type semiconductor layer 132, a p+ type semiconductor layer 132a, a gate insulating film 134, a gate electrode 135a, a source electrode 135b, and a drain electrode 135c. The p+ type semiconductor layer 132a may be a p-type semiconductor layer or may be the same as the p-type semiconductor layer 132.

[0024] FIG. 11 shows a preferred example of a junction field effect transistor (JFET) including an n-type semiconductor layer 141a, a first n+ type semiconductor layer 141b, a second n+ type semiconductor layer 141c, a p-type semiconductor layer 142, a gate electrode 145a, a source electrode 145b and a drain electrode 145c.

[0025] FIG. 12 shows a preferred example of an insulated gate bipolar transistor (IGBT) including an n-type semiconductor layer 151, an n-type semiconductor layer 151a, an n+ type semiconductor layer 151b, a p-type semiconductor layer 152, a gate insulating film 154, a gate electrode 155a, an emitter electrode 155b, and a collector electrode 155c.

[0026] (LED) An example of the semiconductor device of the present invention being a light emitting diode (LED) is shown in Fig. 14. The semiconductor light emitting device of Fig. 14 includes an n-type semiconductor layer 161 on a second electrode 165b, and a light emitting layer 163 is laminated on the n-type semiconductor layer 161. A p-type semiconductor layer 162 is laminated on the light emitting layer 163. A light-transmitting electrode 167 that transmits light generated by the light emitting layer 163 is provided on the p-type semiconductor layer 162, and a first electrode 165a is laminated on the light-transmitting electrode 167. The semiconductor light emitting device of Fig. 15 may be covered with a protective layer except for the electrode portion.

[0027] Examples of materials for the transparent electrode include conductive oxide materials containing indium (In) or titanium (Ti). More specifically, for example, In 2 O 3 , ZnO, SnO 2 , Ga 2 O 3 , TiO 2 , CEO 2 Or, a mixed crystal of two or more of these, or a doped one of these, etc. can be used. By providing these materials by a known means such as sputtering, a translucent electrode can be formed. After forming the translucent electrode, thermal annealing may be performed for the purpose of making the translucent electrode transparent.

[0028] In the semiconductor light-emitting element of FIG. 13, the first electrode 165a is a positive electrode and the second electrode 165b is a negative electrode, and by passing a current through both of them to the p-type semiconductor layer 162, the light-emitting layer 163, and the n-type semiconductor layer 161, the light-emitting layer 163 emits light.

[0029] Examples of materials for the first electrode 165a and the second electrode 165b include metals such as Al, Mo, Co, Zr, Sn, Nb, Fe, Cr, Ta, Ti, Au, Pt, V, Mn, Ni, Cu, Hf, W, Ir, Zn, In, Pd, Nd, Ag, or the like, or alloys thereof, metal oxide conductive films such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), or the like, organic conductive compounds such as polyaniline, polythiophene, or polypyrrole, or mixtures thereof, etc. The method for forming the electrode film is not particularly limited, and the electrode can be formed on the substrate according to a method appropriately selected from wet methods such as printing, spraying, and coating, physical methods such as vacuum deposition, sputtering, and ion plating, and chemical methods such as CVD and plasma CVD, etc., taking into consideration the suitability of the material.

[0030] FIG. 14 shows a main part of a junction barrier Schottky diode (JBS) which is one of the preferred embodiments of the present invention. The JBS in FIG. 14 includes an ohmic electrode 1020, an n-type semiconductor layer 1010a, an n+ type semiconductor layer 1010b, a Schottky electrode 1030, and an electric field relaxation region 1060. The Schottky electrode 1030 includes a metal layer 1030a, a metal layer 1030b, and a metal layer 1030c. In the semiconductor device in FIG. 14, the outer end of the metal layer 1030a and / or the metal layer 1030b as the second electrode layer is located outside the outer end of the metal layer 1030c as the first electrode layer. In the semiconductor device in FIG. 14, the region of the electric field relaxation region 1060 includes at least two electric field relaxation regions 1060 in a plane including at least a part of the portion of the second electrode layer located outside the outer end of the first electrode layer, and the outer end of the second electrode. In the semiconductor device of FIG. 14, the electric field relaxation region 1060 is made of a p-type semiconductor, and forms a PN junction with the n-type semiconductor layer 1010a.

[0031] 14 may be formed by any known means without any particular limitation as long as it does not impede the object of the present invention, for example, by forming a film by vacuum deposition, CVD, sputtering, or various coating techniques, followed by patterning by photolithography, or by directly patterning using a printing technique. EXAMPLES

[0032] Example 1 1 is a diagram showing an example of a preferred embodiment of a film forming apparatus when the atomizing device of the present invention is used as a film forming atomizing stage. The film forming apparatus 19 is composed of a film forming sample 20, a sample stage 21, a carrier gas source 22a, a carrier gas source 22b, a flow rate control valve 23a, a flow rate control valve 23b, a film forming chamber 27, a heater 28, and an atomizing device 30. The atomizing device 30 is composed of a raw material partition wall 24, a raw material liquid to be atomized 24a, an ultrasonic transmission base material 24b, a stage 24c, an ultrasonic transducer 26, an ultrasonic transmission liquid tank 35, and an ultrasonic transmission liquid 36.

[0033] Next, a TiO2 (001) substrate having a tetragonal rutile structure, a square shape with sides of 10 mm and an average thickness of 500 nm, was placed on the sample stage 21 as the film-forming sample 20, and the heater 28 was operated to raise the temperature in the film-forming chamber 27 to 750°C. Next, the flow rate control valve 23 was opened to supply carrier gas from the carrier gas source 22 into the film-forming chamber 27, and after the atmosphere in the film-forming chamber 27 was sufficiently replaced with the carrier gas, the flow rate of the carrier gas was adjusted to 3 L / min. Oxygen gas was used as the carrier gas.

[0034] Next, the ultrasonic vibrator 26 was vibrated at 3.0 MHz, and the vibration was propagated to the raw material solution 24a through the ultrasonic transmitter 25a, thereby atomizing the raw material solution 24a to generate raw material fine particles. The raw material fine particles were introduced into the film formation chamber 27 by the carrier gas, reacted in the film formation chamber 27, and tetragonal GeO was formed on the film formation sample 20 by the CVD reaction on the film formation surface of the film formation sample 20. 2 A crystalline film was formed.

[0035] Next, the amorphous phase was removed by immersing the sample in ultrapure water for 3 minutes and applying ultrasonic vibration. After removing the amorphous phase, the raw material 24a was supplied to the crystal on the TiO2 substrate (001) to re-grow the crystal. GeO with a tetragonal rutile structure 2 A crystal film was formed with a thickness of 1.7 μm.

[0036] The obtained crystalline film was measured using an X-ray diffraction apparatus. The results of the XRD analysis are shown in Figure 2. As is clear from Figure 2, the obtained crystalline film is GeO with a (002) oriented tetragonal rutile structure with good crystallinity. 2 It was a crystalline film.

[0037] The surface of the obtained crystal film was observed using a SEM. The SEM image is shown in Figure 3. As is clear from Figure 3, the GeO film has excellent surface smoothness and good crystallinity over a large area. 2 In addition, when the surface of the obtained crystal film was evaluated using EDS, it was found that a crystal film had formed over the entire surface, as shown in Figure 4.

[0038] Comparative Example 1 The same procedure as in Example 1 was carried out except that the amorphous phase was removed with ultrapure water and the raw material was not supplied to the crystal again. The result of measuring the obtained crystal film using an XRD diffractometer is shown in FIG. 5. It was found from FIG. 5 that the crystallinity was poor. From this, it was found that the crystal film obtained in Example 1 had excellent crystallinity.

[0039] The surface of the obtained crystal film was observed using an SEM. An SEM image is shown in FIG. 6. As is clear from FIG. 6, crystal grains were only partially formed. This indicates that the crystal film obtained in Example 1 is a GeO film having excellent surface smoothness and good crystallinity over a large area. 2 It was found that a crystalline film was obtained.

[0040] In addition, the surface of the obtained crystal film was evaluated using EDS, and as shown in Figure 7, GeO2 It was found that crystals were partially formed. This shows that the crystal film obtained in Example 1 had a crystal film formed over the entire surface. [Industrial Applicability]

[0041] The crystal and layered structure of the present invention are suitable for use in, for example, semiconductor devices. [Explanation of symbols]

[0042] 19 Film forming equipment 20 Film sample 21 Sample stage 22a Carrier gas source 22b Dilution gas source 23a Flow control valve 23b Flow control valve 24 Raw material bulkhead 24a Raw material liquid for atomization 24b Ultrasonic transparent base material 24c units 26 Ultrasonic transducer 27 Film forming room 28 Heater 30 Atomization device 35 Ultrasonic transmission fluid tank 36 Ultrasonic transmission fluid 37 Film forming room 101a n-type semiconductor layer 101b n+ type semiconductor layer 102 p-type semiconductor layer 103 Metal layer 104 Insulator Layer 105a Schottky electrode 105b Ohmic electrode 111a n-type semiconductor layer 111b n+ type semiconductor layer 114 Semi-insulating layer 115a Gate electrode 115b Source electrode 115c Drain electrode 118 Buffer layer 121a Wide band gap n-type semiconductor layer 121b Narrow band gap n-type semiconductor layer 121c n+ type semiconductor layer 123 p-type semiconductor layer 124 Semi-insulating layer 125a Gate electrode 125b Source electrode 125c Drain electrode 128 Buffer layer 129 Board 131a n-type semiconductor layer 131b First n+ type semiconductor layer 131c second n+ type semiconductor layer 132 p-type semiconductor layer 134 Gate insulating film 135a Gate electrode 135b Source electrode 135c Drain electrode 138 Buffer layer 139 Semi-insulating layer 141a n-type semiconductor layer 141b First n+ type semiconductor layer 141c second n+ type semiconductor layer 142 p-type semiconductor layer 145a Gate electrode 145b Source electrode 145c Drain electrode 151 n-type semiconductor layer 151a n-type semiconductor layer 151b n+ type semiconductor layer 152 p-type semiconductor layer 154 Gate insulating film 155a Gate electrode 155b Emitter electrode 155c Collector electrode 161 n-type semiconductor layer 162 p-type semiconductor layer 163 Light-emitting layer 165a First electrode 165b Second electrode 167 Translucent electrode 169 Board 1010a n-type semiconductor 1010b n+ type semiconductor 1020 Ohmic electrode 1030 Schottky electrode 1030a metal layer 1030b metal layer 1030c metal layer 1060 Electrolytic relaxation region

Claims

1. A crystal film containing a metal oxide containing germanium as a main component, the crystal film having an area of ​​100 μm ２ The crystal film is characterized in that the film thickness is 1 μm or more.

2. 2. The crystal film according to claim 1, wherein said crystal film has a tetragonal crystal structure.

3. 2. The crystalline film of claim 1 which is a single crystal film.

4. 10. A laminated structure in which a crystal film is laminated directly or via another layer on a crystal substrate, the crystal film being the crystal film according to claim 1.

5. 5. The laminated structure according to claim 4, wherein the crystal substrate has a tetragonal crystal structure.

6. 5. A semiconductor device including a crystal film or a laminated structure, wherein the crystal film is the crystal film according to claim 1, and the laminated structure is the laminated structure according to claim 4.

7. 7. The semiconductor device according to claim 6, which is a power device.

8. 7. The semiconductor device according to claim 6, which is a Schottky barrier diode (SBD), a junction barrier Schottky diode (JBS), a high electron mobility transistor (HEMT), a metal oxide semiconductor field effect transistor (MOSFET), a junction field effect transistor (JFET), an insulated gate bipolar transistor (IGBT), or a light emitting diode (LED).

9. 7. An electronic device including a semiconductor device, the semiconductor device being the semiconductor device according to claim 6.

10. A system including an electronic device, the electronic device being the electronic device according to claim 6.

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