Crystalline oxide semiconductor film, laminated structure, and semiconductor device

Abstract

The present invention is a crystalline oxide semiconductor film which is a uniaxially oriented film that contains alpha-Ga2O3 as a main component, and which is characterized in that: the crystalline oxide semiconductor film is a uniaxially oriented film that contains alpha-Ga2O3 as a main component; the total area (C2) of rotation domain peaks obtained by phi scanning by X-ray diffraction measurement of the asymmetric plane of the crystalline oxide semiconductor film with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is such that the count of the number of the peaks of the crystalline oxide semiconductor film is 1,000-1,000,000 with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film, and the count of the number of the peaks of the crystalline oxide semiconductor film is 1,000,000-1,000,000 with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film. The total area (C2) of the peaks of the rotational domains is less than 5 counts. This makes it possible to provide a crystalline oxide semiconductor film which has a further reduced rotation domain, has good crystallinity, and is particularly useful for semiconductor devices.

Description

Technical Field

[0001] The present invention relates to a crystalline oxide semiconductor film, a laminated structure, and a semiconductor device. Background Art

[0002] As a next-generation switching element capable of achieving high breakdown voltage, low loss, and high heat resistance, semiconductor devices using gallium oxide (Ga2O3) having a relatively large bandgap have attracted attention, and it is expected that they will be applied to power semiconductor devices such as inverters. According to Non-Patent Document 1, the bandgap of this gallium oxide can be controlled by forming a mixed crystal with indium or aluminum, respectively, or by forming a mixed crystal in combination. Among them, In X1 Al Y1 Ga Z1 O3 (0 ≤ X1 ≤ 2, 0 ≤ Y1 ≤ 2, 0 ≤ Z1 ≤ 2, X1 + Y1 + Z1 = 1.5 to 2.5) The InAlGaO-based semiconductor represented by is a very attractive material.

[0003] In Patent Document 1, a Ga2O3-based semiconductor element formed by forming a p-type α-(Al X2 Ga 1-X2 )2O3 single crystal film (0 ≤ X2 < 1) on an α-Al2O3 substrate is described. However, in the semiconductor element described in Patent Document 1, there are problems in crystal quality, and there are many restrictions when applied to semiconductor elements. In addition, in the MBE method, it is difficult to fabricate an α-Ga2O3 single crystal film (when X2 = 0), and in order to obtain a p-type semiconductor, ion implantation and heat treatment at high temperature are required. Therefore, p-type α-Ga2O3 itself is difficult to realize, and in fact, the semiconductor element described in Patent Document 1 itself is difficult to realize.

[0004] Patent Document 2 describes a corundum structure oxide crystal containing aluminum and gallium, and describes that phase change at high temperature can be suppressed. However, as a mixed crystal having a relatively large bandgap, there are still many technical problems. For example, even when used as a buffer layer, there are rotational domains or warping on the epitaxially grown crystal, which is not necessarily satisfactory.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2013-058637

[0008] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2015-017027

[0009] Patent Document 3: Japanese Patent No. 6876895

[0010] Patent Document 4: Japanese Patent No. 7016489

[0011] Patent Document 5: Japanese Patent No. 7265624

[0012] Non-patent document 1: Kentaro Kaneko, "Growth and Properties of Corundum-structured Gallium Oxide Mixed Crystal Thin Films", PhD thesis, Kyoto University, March 2013 Summary of the invention

[0013] 1. Technical issues to be resolved

[0014] In particular, it is desired to provide a crystalline oxide semiconductor film with reduced rotation domains and good crystallinity.

[0015] Regarding this technical problem, Patent Documents 3 and 4 describe the following examples, that is, by forming α-Ga2O3 on a substrate via a buffer layer of a quantum well structure, α-Ga2O3 containing a dopant and having a rotation domain content of less than 0.02% and a film thickness of more than 1 μm is formed. In addition, Patent Documents 3 and 4 describe the following examples, that is, by forming α-Ga2O3 via a buffer layer of a quantum well structure, α-Ga2O3 containing a dopant and having a rotation domain count of 0 count relative to 100,000 counts is formed.

[0016] However, the inventors of the present application implemented film formation on a 4-inch (100 mm in diameter) substrate according to Patent Documents 3 and 4, and conducted a careful analysis. As a result, rotation domains exist at the following ratio: the total area of the peaks of the rotation domains relative to the total area of the peaks obtained by X-ray diffraction φ scanning of the (104) plane as an asymmetric plane is 2 counts relative to 500,000 counts. This number is 0.4 counts relative to 100,000 counts, that is, if rounded to the first decimal place, it is 0 counts, but it still contains rotation domains. In addition, when film formation is implemented on a substrate larger than 6 inches (150 mm in diameter), more rotation domains will be further included. In the inventions described in Patent Documents 3 and 4, the reduction of rotation domains is insufficient, and it is necessary to further reduce rotation domains.

[0017] In addition, Patent Document 5 describes an example of α-Ga2O3 formed substantially without rotational domains over a large area. However, when the inventors of the present application carried out film formation on a 4-inch (diameter 100 mm) substrate, a 6-inch (diameter 150 mm) substrate, or an 8-inch (diameter 200 mm) substrate according to Patent Document 5, as a result, it was found that the peak intensity obtained by φ-scan of X-ray diffraction measurement for the (104) plane, which is an asymmetric plane, was 158 counts relative to a ratio of 100,000 counts (content ratio: 0.158%), that is, a relatively large number of rotational domains were found. Also, the peak intensity of the rotational domains increases as the distance from the center of the substrate increases. In particular, in the 6-inch substrate or the 8-inch substrate, the content ratio of the rotational domains becomes uneven within the plane. Since the method described in Patent Document 5 involves film formation by supplying mist to the center of the substrate, it is considered that the larger the substrate, the more uneven it becomes. As described above, the reduction of rotational domains in the method described in Patent Document 5 is still insufficient, and there is a particular need for a method for further reducing rotational domains in a large-diameter substrate.

[0018] The present invention has been completed to solve the above problems, and an object thereof is to provide a crystalline oxide semiconductor film in which rotational domains are further reduced, having good crystallinity, and being particularly useful for semiconductor devices.

[0019] (2) Technical Solution

[0020] The present invention has been made to achieve the above object, and provides a crystalline oxide semiconductor film, characterized in that the crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component, and the total area (C2) of peaks of rotational domains obtained by φ-scan of X-ray diffraction measurement for an asymmetric plane of the crystalline oxide semiconductor film with respect to the total area (C1) of peaks of the crystalline oxide semiconductor film is: with respect to 1,000,000 counts of the total area (C1) of peaks of the crystalline oxide semiconductor film, the total area (C2) of peaks of the rotational domains is less than 5 counts.

[0021] According to such a crystalline oxide semiconductor film, rotational domains are further reduced, warpage and cracks are further reduced, and the crystallinity is good, and it is particularly useful for semiconductor devices.

[0022] At this time, it can be set that with respect to 1,000,000 counts of the total area (C1) of peaks of the crystalline oxide semiconductor film, the total area (C2) of peaks of the rotational domains is 0 counts.

[0023] According to such a crystalline oxide semiconductor film, rotational domains are further reduced, warpage and cracks are further reduced, and the crystallinity is good, and it is particularly more useful for semiconductor devices.

[0024] The present invention also provides a crystalline oxide semiconductor film, which is characterized in that the crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component, and the total area (C2) of the peaks of the rotational domains obtained by φ scanning by X-ray diffraction of the asymmetric plane of the crystalline oxide semiconductor film with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film of 500,000 counts, the total area (C2) of the peaks of the rotational domains is 0 count.

[0025] According to such a crystalline oxide semiconductor film, the rotational domains are further reduced, the warpage and cracks are further reduced, and the crystallinity is good, which is particularly useful for semiconductor devices.

[0026] In this case, it can be set that the crystalline oxide semiconductor film contains a dopant.

[0027] If it is such a crystalline oxide semiconductor film, by containing a dopant, the flow of electrons or holes can be controlled.

[0028] In addition, it can be set that the film thickness of the crystalline oxide semiconductor film is 1 μm or more.

[0029] If it is such a crystalline oxide semiconductor film, it is more useful for semiconductor devices.

[0030] In addition, it can be set that in the metals contained in the crystalline oxide semiconductor film, Ga accounts for 90 atomic% or more.

[0031] If it is such a crystalline oxide semiconductor film, it is more useful for semiconductor devices.

[0032] In addition, it can be set that the crystalline oxide semiconductor film has a size of 2 inches (50 mm) or more in diameter. Further, it can be set that the crystalline oxide semiconductor film has a size of 6 inches (150 mm) or more in diameter.

[0033] If it is such a crystalline oxide semiconductor film, the larger the area, the more excellent the productivity.

[0034] In addition, it can be set that the full width at half maximum of the rocking curve of the plane parallel to the main plane of the crystalline oxide semiconductor film is 25 arcseconds or less, and it can be set that the full width at half maximum of the rocking curve of the asymmetric plane is 2500 arcseconds or less.

[0035] If it is such a crystalline oxide semiconductor film, the crystallinity is excellent and it is more useful for semiconductor devices.

[0036] In addition, it can be set that the crystalline oxide semiconductor film has a c-plane as the main plane.

[0037] If it is such a crystalline oxide semiconductor film, it is more useful for semiconductor devices.

[0038] In addition, it is possible to make the full width at half maximum of the rocking curve of the (006) plane of the crystalline oxide semiconductor film 25 arcseconds or less.

[0039] If it is such a crystalline oxide semiconductor film, it has excellent crystallinity and is more useful for semiconductor devices.

[0040] In addition, it is possible to make the full width at half maximum of the rocking curve of the (104) plane of the crystalline oxide semiconductor film 2500 arcseconds or less.

[0041] If it is such a crystalline oxide semiconductor film, it has excellent crystallinity and is more useful for semiconductor devices.

[0042] In addition, it is possible to make the number of cracks per 1 mm 2 of the crystalline oxide semiconductor film zero.

[0043] If it is such a crystalline oxide semiconductor film, it is more useful for semiconductor devices.

[0044] At this time, it is possible to make the content rate [%] of the rotational domain calculated by using the total area (C1) of the peaks of the crystalline oxide semiconductor film and the total area (C2) of the peaks of the rotational domain and C1 / C2×100 less than 0.0005%.

[0045] If it is such a crystalline oxide semiconductor film, it has even more excellent crystallinity and is more useful for semiconductor devices.

[0046] At this time, it is possible to make the content rate of the rotational domain less than 0.0005% in the measurement at five positions in the plane of the crystalline oxide semiconductor film.

[0047] If it is such a crystalline oxide semiconductor film, it is more useful for semiconductor devices.

[0048] At this time, it is possible to make the coefficient of variation of the content rate of the rotational domain measured at five positions in the plane of the crystalline oxide semiconductor film less than 0.35.

[0049] If it is such a crystalline oxide semiconductor film, it is further useful for semiconductor devices.

[0050] In addition, it is possible to make the content rate [%] of the rotational domain calculated by using the total area (C1) of the peaks of the crystalline oxide semiconductor film and the total area (C2) of the peaks of the rotational domain and C1 / C2×100 less than 0.0002%.

[0051] Such a crystalline oxide semiconductor film has better crystallinity and is more useful for semiconductor devices.

[0052] Furthermore, the content of the rotated domains in measurements at five locations within the plane of the crystalline oxide semiconductor film can be set to be less than 0.0002%.

[0053] Such a crystalline oxide semiconductor film is more useful for a semiconductor device.

[0054] Furthermore, among the peaks obtained by X-ray diffraction φ scanning of the asymmetric plane of the crystalline oxide semiconductor film, the count of the highest intensity peak among the peaks of the rotated domain can be 0 count with respect to 150,000 counts of the highest intensity peak.

[0055] Such a crystalline oxide semiconductor film has further excellent crystallinity and is more useful for semiconductor devices.

[0056] The present invention provides a stacked structure, which is formed by stacking a substrate and a crystalline oxide semiconductor film on the substrate with a buffer layer therebetween, characterized in that the buffer layer contains Ga as a main component, and is a stacked structure in which three or more buffer films are stacked in such a manner that the composition ratio of Ga increases from the substrate side of the buffer layer toward the crystalline oxide semiconductor film side, and the film thickness of at least two of the buffer films is greater than 200 nm and less than 650 nm,

[0057] The substrate has a corundum structure, and the crystalline oxide semiconductor film is the crystalline oxide semiconductor film of the present invention.

[0058] According to such a stacked structure, the rotation domain of the crystalline oxide semiconductor film is further reduced, and the warping and cracking are further reduced, and the crystallinity is good, which is particularly useful for semiconductor devices.

[0059] In this case, the film thickness of all the buffer films of the buffer layer can be set to be greater than or equal to 200 nm and less than or equal to 650 nm.

[0060] Such a laminated structure can suppress the introduction of warpage and defects.

[0061] Furthermore, the buffer layer may include Al, and three or more buffer films may be stacked such that the composition ratio of Al decreases from the substrate side of the buffer layer toward the crystalline oxide semiconductor film side.

[0062] In such a stacked structure, stress caused by the lattice constant difference can be alleviated, warping, cracks, and rotational domains can be suppressed, and a crystalline oxide semiconductor film with a small in-plane distribution of film thickness can be obtained at an excellent film formation rate.

[0063] The present invention provides a semiconductor device, characterized in that it includes at least one of the crystalline oxide semiconductor film of the present invention or the stacked structure of the present invention.

[0064] According to such a semiconductor device, since the crystalline oxide semiconductor film of the present invention with further reduced rotational domains and good crystallinity is used, the device characteristics are good.

[0065] In this case, the semiconductor device can be any one of a semiconductor laser, a diode, or a transistor.

[0066] If it is such a semiconductor device, a semiconductor laser, a diode, or a transistor with good device characteristics can be provided.

[0067] (III) Advantageous Effects

[0068] If it is the crystalline oxide semiconductor film of the present invention, a crystalline oxide semiconductor film with further reduced rotational domains, good crystallinity, and particularly useful for semiconductor devices can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is a typical example of the φ scan of the asymmetric plane ((104) plane) of the crystalline oxide semiconductor film of the present invention, and it is a diagram showing the results of Example 1.

[0070] Figure 2 It is a diagram showing one embodiment of the structure of the stacked structure of the present invention.

[0071] Figure 3 It is a diagram showing another embodiment of the structure of the stacked structure of the present invention.

[0072] Figure 4 It is a diagram showing an example of the Schottky barrier diode of the present invention.

[0073] Figure 5 It is a diagram showing an example of the high electron mobility transistor of the present invention.

[0074] Figure 6 It is a diagram showing an example of the semiconductor field effect transistor of the present invention.

[0075] Figure 7 It is a diagram showing an example of the insulated gate bipolar transistor of the present invention.

[0076] Figure 8 A diagram showing an example of the light-emitting element diode of the present invention.

[0077] Figure 9 A diagram showing an example of the film-forming apparatus of the present invention.

[0078] Figure 10 A diagram showing another example of the film-forming apparatus of the present invention.

[0079] Figure 11 A diagram showing an example of the atomizing section of the present invention.

[0080] Figure 12 A diagram showing an example of the film-forming apparatus of the present invention.

[0081] Figure 13 A diagram showing another example of the film-forming apparatus of the present invention.

[0082] Figure 14 A diagram showing the measurement position of the present invention.

[0083] Figure 15 A diagram showing the result of the φ scan of the (104) plane in Comparative Example 1. Detailed Description of the Invention

[0084] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0085] As described above, there is a demand for a crystalline oxide semiconductor film with further reduced rotational domains and good crystallinity.

[0086] The inventors of the present invention have seriously studied the above technical problems, and as a result, have successfully created a crystalline oxide semiconductor film, which is characterized in that the crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component, and the total area (C2) of the peaks of the rotational domains obtained by the φ scan of the asymmetric plane of the crystalline oxide semiconductor film by X-ray diffraction measurement with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is: with respect to 1,000,000 counts of the total area (C1) of the peaks of the crystalline oxide semiconductor film, the total area (C2) of the peaks of the rotational domains is less than 5 counts. According to such a crystalline oxide semiconductor film, not only are the rotational domains further reduced, but also the warpage and cracks are further reduced, and the problems of the past can be solved all at once, and thus the present invention has been completed.

[0087] In addition, the inventors of the present invention have successfully created a crystalline oxide semiconductor film, which is characterized in that the crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component. The total area (C2) of the peaks of the rotational domains obtained by φ-scanning of the asymmetric plane of the crystalline oxide semiconductor film by X-ray diffraction with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is as follows: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film of 500,000 counts, the total area (C2) of the peaks of the rotational domains is 0 count. According to such a crystalline oxide semiconductor film, not only are the rotational domains further reduced, but also the warpage and cracks are further reduced, and the problems of the prior art can be solved at once, and thus the present invention is completed.

[0088] Hereinafter, description will be made with reference to the drawings.

[0089] The crystalline oxide semiconductor film of the present invention is a crystalline oxide semiconductor film, wherein the crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component. The total area (C2) of the peaks of the rotational domains obtained by φ-scanning of the asymmetric plane of the crystalline oxide semiconductor film by X-ray diffraction with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is as follows: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film of 1,000,000 counts, the total area (C2) of the peaks of the rotational domains is less than 5 counts.

[0090] In addition, the crystalline oxide semiconductor film of the present invention is a crystalline oxide semiconductor film, wherein the crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component. The total area (C2) of the peaks of the rotational domains obtained by φ-scanning of the asymmetric plane of the crystalline oxide semiconductor film by X-ray diffraction with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is as follows: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film of 500,000 counts, the total area (C2) of the peaks of the rotational domains is 0 count. Figure 1 A typical example of the φ-scanning measurement of the present invention is shown in, and the detailed content will be described later.

[0091] The crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as the main component, and more preferably a single crystal. In addition, α-Ga2O3 is a metal oxide having a corundum structure and has trigonal symmetry. The main component referred to herein means that α-Ga2O3 accounts for 50 to 100 mol% of the crystalline oxide semiconductor film. In the present application, among the metal components of the crystalline oxide semiconductor film, Ga only needs to account for 50 atomic% or more, preferably 90 atomic% or more, and more preferably 95 atomic% or more. In addition, as long as it is a metal oxide capable of obtaining a corundum structure other than α-Ga2O3, there is no particular limitation, and for example, it can be set to contain an oxide of any one of aluminum, titanium, vanadium, chromium, iron, gallium, rhodium, indium, and iridium.

[0092] In the present application, the uniaxially oriented film means a film in which peaks can be observed only in a specific plane orientation in the X-ray diffraction measurement of the main plane of the crystalline oxide semiconductor film. For example, when the c-plane is the main plane, it is a film in which peaks can be observed only on a part of the plane parallel to the (006) plane.

[0093] The total area of the peaks (C1) of the crystalline oxide semiconductor film and the total area of the peaks (C2) of the rotational domains are measured using an X-ray diffraction measurement device. More specifically, it can be measured by performing a φ scan of the asymmetric plane using an X-ray diffraction measurement device. The asymmetric plane refers to a plane inclined with respect to the main plane of the crystalline oxide semiconductor film. More specifically, when the c-plane is the main plane, examples of the asymmetric plane include the (104) plane, when the a-plane is the main plane, examples of the asymmetric plane include the (300) plane, when the r-plane is the main plane, examples of the asymmetric plane include the (006) plane, when the m-plane is the main plane, examples of the asymmetric plane include the (104) plane, and when the n-plane is the main plane, examples of the asymmetric plane include the (110) plane, etc.

[0094] The φ scan means a method of using an X-ray diffraction measurement device to fix the angles of 2θ, ω, and χ, and rotating the φ axis parallel to the normal line of the sample main plane from 0 to 360° for measurement. For example, the angle formed by the asymmetric plane and the sample surface is calculated by the inner product of the reciprocal lattice vectors, and the χ axis is tilted so that the direction of the scattering vector formed by the X-ray incident light and the X-ray diffracted light is the same as the direction of the reciprocal lattice vector of the asymmetric plane. Then, in the state where the χχω axes are tilted, a 2θ / ω scan is performed, and the respective angles are fixed to 2θ and ω that obtain the diffraction peak of the asymmetric plane. Next, in the state where χ, 2θ, and ω are fixed, scanning is performed by rotating the φ axis to obtain the peaks.

[0095] In the φ scan of the asymmetric plane, peaks appear at angular intervals corresponding to the symmetry of the asymmetric plane with respect to the φ axis. For example, in a sample with the c-plane as the main plane, when measuring the (104) plane as the asymmetric plane, since the (104) plane has three-fold symmetry with respect to the φ axis, three peaks are observed at intervals of 120°.

[0096] The total area (C2) of the peaks of the rotational domains obtained by φ scan with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film of 1,000,000 counts, the total area (C2) of the peaks of the rotational domains is less than 5 counts.

[0097] In addition, the total area (C2) of the peaks of the rotational domains obtained by φ scan with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film of 500,000 counts, the total area (C2) of the peaks of the rotational domains is 0 counts.

[0098] As Figure 1 A typical example of the φ scan of the asymmetric plane ((104) plane) of the crystalline oxide semiconductor film of the present invention is shown. By fixing 2θ and ω at the positions where the peaks are obtained and rotating the φ axis parallel to the sample surface normal, the φ scan of the (104) plane is thus carried out to obtain the result. Preferably: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film of 1,000,000 counts, the total area (C2) of the peaks of the rotational domains is 0 counts, and more preferably: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film of 3,000,000 counts, the total area (C2) of the peaks of the rotational domains is 0 counts. The above-mentioned crystalline oxide semiconductor film has excellent characteristics when used in semiconductor devices.

[0099] In addition, the total area (C1) of the peaks of the crystalline oxide semiconductor film and the total area (C2) of the peaks of the rotational domains mentioned here can be calculated by accumulating the counts at each angle of the peaks in the X-ray diffraction measurement. For example, when a peak A appears at φ = 90.00~90.10° and the step size of the φ axis is 0.02°, the area of peak A can be calculated by accumulating the counts at 90.00°, 90.02°, 90.04°, 90.06°, 90.08°, and 90.10°.

[0100] Among them, the content ratio of the rotational domains can be obtained by using the total area (C1) of the peaks of the crystalline oxide semiconductor film in the φ scan and the total area (C2) of the peaks of the rotational domains, with (content ratio of rotational domains [%]) = C2 / C1 × 100. For example, when the total area of the peaks of the crystalline oxide semiconductor film is 100,000 counts and the total area of the peaks of the rotational domains is 5 counts, the content ratio of the rotational domains is 0.005%. The content ratio of the rotational domains can be less than 0.0005%, preferably less than 0.0002%, more preferably less than 0.0001%, and further preferably 0%.

[0101] In addition, in the measurement at five positions in the plane of the crystalline oxide semiconductor film, the content ratio of the rotational domains can be less than 0.0005% for all, preferably less than 0.0002%, more preferably less than 0.0001%, and further preferably 0%. Additionally, for the measurement positions, for example, when the shape of the crystalline oxide semiconductor film is circular, in the polar coordinate system where the radius of the substrate is set as R, the center of the substrate is set as the origin 0, the distance from the origin 0 is set as r, and the angle formed with the x-axis is set as θ [°], the measurement positions can be set as polar coordinates (r, θ) = (0, 0), (0.5R, 0), (0.5R, 90), (0.5R, 180), (0.5R, 270). When the shape of the crystalline oxide semiconductor film is quadrilateral, it can be set as a total of five points, that is, one point at the center position and four points at the midpoint positions of the straight lines connecting the center and the midpoints of each side. Figure 11 As shown, in the polar coordinate system where the radius of the substrate is set as R, the center of the substrate is set as the origin 0, the distance from the origin 0 is set as r, and the angle formed with the x-axis is set as θ [°], the measurement positions can be set as polar coordinates (r, θ) = (0, 0), (0.5R, 0), (0.5R, 90), (0.5R, 180), (0.5R, 270). When the shape of the crystalline oxide semiconductor film is quadrilateral, it can be set as a total of five points, that is, one point at the center position and four points at the midpoint positions of the straight lines connecting the center and the midpoints of each side.

[0102] In addition, at this time, the coefficient of variation of the content ratio of the rotational domains measured at five places in the plane can be less than 0.35, preferably 0.25 or less. If it is such a crystalline oxide semiconductor film, it is further useful for the semiconductor device. Additionally, the coefficient of variation can be calculated by the following formula.

[0103] [Mathematical formula 1]

[0104]

[0105] In addition, at this time, among the peaks obtained by φ scan in X-ray diffraction measurement of the asymmetric plane of the crystalline oxide semiconductor film, with respect to the count (peak height) of the peak with the highest intensity being 150,000 counts, the count (peak height) of the peak with the highest intensity in the peaks of the rotational domains can be 0 counts, and more preferably with respect to the count (peak height) of the peak with the highest intensity being 300,000 counts, the count (peak height) of the peak with the highest intensity in the peaks of the rotational domains is 0 counts.

[0106] The crystalline oxide semiconductor film preferably has the c-plane as the main plane. Thus, it is more suitable for semiconductor devices. In addition, the full width at half maximum of the rocking curve obtained by ω-scan in X-ray diffraction measurement of the plane parallel to the main plane of the crystalline oxide semiconductor film (for example, the (006) plane when the c-plane is the main plane) can be 25 arcseconds or less, preferably 16 arcseconds or less, and more preferably 10 arcseconds or less. The smaller the full width at half maximum, the more excellent the crystallinity and the better the device characteristics.

[0107] In addition, the full width at half maximum of the rocking curve obtained by ω-scan in X-ray diffraction measurement of the asymmetric plane of the crystalline oxide semiconductor film (for example, the (104) plane when the c-plane is the main plane) can be 2500 arcseconds or less, preferably 2000 arcseconds or less, and more preferably 1500 arcseconds or less. The smaller the full width at half maximum, the more excellent the crystallinity. Especially when used in semiconductor devices, etc., the device characteristics are excellent.

[0108] In addition, the thickness of the crystalline oxide semiconductor film is not particularly limited. In the present invention, it can be 1 μm or more, preferably 2 μm or more, and more preferably 3 μm or more. Thus, it is more suitable for semiconductor devices. The upper limit of the thickness is not particularly limited. For example, it can be set to 1000 μm or less, 500 μm or less, or 100 μm or less.

[0109] In addition, in the present invention, the warp of the crystalline oxide semiconductor film is preferably 0.21 μm or less, and more preferably 0.17 μm or less. In addition, "warp" means the shortest distance between the shortest straight line passing through the two ends of the film (for example, the two ends within 5 mm) and the concave vertex or convex vertex. In the present invention, for example, when the shortest distance between the shortest straight line passing through the two ends within 5 mm of the film and the concave vertex or convex vertex is taken as the warp, the warp is preferably less than 0.042 μm / mm.

[0110] A dopant can be included in the oxide semiconductor film. By including a dopant, the flow of electrons or holes can be controlled. The dopant is not particularly limited. For example, n-type dopants such as tin, germanium, silicon, titanium, zirconium, vanadium, or niobium can be cited, or p-type dopants such as copper, silver, tin, cobalt, iridium, or rhodium, etc. The concentration of the dopant can be, for example, about 1.0×10 16 ~1.0×10 22 / cm 3 , and can be set to a low concentration of about 1.0×10 17 / cm 3 or less, or can also be set to a high concentration of about 1.0×10 20 / cm 3 or more.

[0111] The area of the crystalline oxide semiconductor film is preferably equivalent to an area of 2 inches (50 mm) in diameter or more, more preferably equivalent to an area of 4 inches (100 mm) in diameter or more, and further preferably equivalent to an area of 6 inches (150 mm) in diameter or more. There is no particular limitation on the upper limit of the area, and the productivity is more excellent as the area is larger. For example, it can be set to an area equivalent to 12 inches (300 mm) in diameter or less.

[0112] In addition, in the present invention, it is preferable that the number of cracks in the crystalline oxide semiconductor film per 1 mm 2 is 0, that is, it does not contain cracks. There is no particular limitation on the method for evaluating the number of cracks. The number of cracks on the entire surface of the crystalline oxide semiconductor film can be inspected by an optical surface inspection machine, and the number of cracks per 1 mm 2 can be calculated by dividing the number of cracks by the inspection area. Alternatively, SEM, TEM, an optical microscope, etc. can also be used to observe 1 mm 2 and count the number of cracks.

[0113] By appropriately performing structural design, the crystalline oxide semiconductor film of the present invention can be used for semiconductor devices. In addition, examples of semiconductor devices will be described in detail later.

[0114] (Manufacturing method of crystalline oxide semiconductor film)

[0115] As described later, the crystalline oxide semiconductor film of the present invention can be obtained by appropriately selecting a substrate, a buffer layer, and performing film formation. There is no particular limitation on the film formation method, and it can be achieved by known broad methods such as plasma CVD, LPCVD (low-pressure CVD), APCVD (atmospheric pressure CVD), mist CVD, HVPE, sputtering, ion plating, etc. It is preferable to use the mist CVD method for film formation. The film formation method by the mist CVD method will be described in detail later.

[0116] (Stacked structure)

[0117] Figure 2 , Figure 3 are diagrams showing a scheme of the structure of the stacked structure of the present invention. The stacked structures 100 and 200 having the crystalline oxide semiconductor film of the present invention basically include substrates 101 and 201, buffer layers 112 and 212, and crystalline oxide semiconductor films 103 and 203, and are composed of buffer layers 112 and 212 formed on the main surfaces of substrates 101 and 201 and crystalline oxide semiconductor films 103 and 203 further formed on these buffer layers 112 and 212.

[0118] (Substrate)

[0119] The substrates 101 and 201 are not particularly limited as long as they contain a crystalline substance as the main component, and they can be well-known substrates. They can be insulators, conductors, semiconductors, single crystals, or polycrystals. For example, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron or aluminum, stainless steel, gold, silicon, sapphire, quartz, glass, gallium oxide, lithium niobate, lithium tantalate, etc. can be cited, but are not limited to these materials. Substrates having a corundum structure are particularly preferred.

[0120] In addition, it is preferable to use a substrate in which the main component metal element contained in the largest amount among the metal elements contained in the substrate is aluminum. Among them, from the aspects of quality and cost, it is preferable to use a sapphire wafer.

[0121] The plane orientation of the main plane of the substrate is not particularly limited. When it is a sapphire wafer, for example, planes such as the c-plane, m-plane, a-plane, r-plane, and n-plane can be used. In addition, it can have an offset angle with respect to the front surface. The offset angle is not particularly limited and is preferably 0 to 15°.

[0122] The thickness of the substrates 101 and 201 is not particularly limited. From the aspect of cost, it is preferably about 200 to 800 μm. In addition, the area of the main surface of the substrates 101 and 201 can be 10 cm 2 Above, it is preferably an area equivalent to a diameter of about 5 cm (2 inches) or more, more preferably an area equivalent to a diameter of about 10 cm (4 inches) or more, and further preferably an area equivalent to a diameter of about 15 cm (6 inches) or more. As described above, if the substrates 101 and 201 are large-diameter substrates, the crystalline oxide semiconductor films 103 and 203 formed on the substrates 101 and 201 become further higher in quality and productivity. In addition, the degree of freedom in device design increases. The upper limit of the area is not particularly limited, and the larger the area, the more excellent the productivity. For example, it can be set to an area equivalent to a diameter of 12 inches (300 mm) or less. In the present invention, the shape of the substrates 101 and 201 is not particularly limited. It can be circular or a quadrilateral such as a square.

[0123] (Buffer layer)

[0124] In addition, in the laminated structure of the present invention, the buffer layer contains Ga as the main component, and it is a laminated structure of three or more buffer films laminated in such a manner that the composition ratio of Ga increases from the substrate side of the buffer layer to the crystalline oxide semiconductor film side, and the film thickness of at least two of these buffer films is 200 nm or more and 650 nm or less. In addition, the buffer layer is preferably an oxide semiconductor having a corundum structure.

[0125] The buffer layer, such as Figure 2The buffer layer 112 can be directly formed on the substrate 101 or can be formed on the substrate 101 with other layers in between. As other layers, for example, when a peeling layer for separating the crystalline oxide semiconductor film from the substrate is introduced, etc., the buffer layer 212 as shown in Figure 3 is formed on the peeling layer 204.

[0126] The buffer layer 112 is a laminated structure of a plurality of buffer films 102a, 102b, 102c having different compositions from each other, and the buffer layer 212 is also a laminated structure of a plurality of buffer films 202a, 202b, 202c having different compositions from each other. The buffer films 102a, 102b, 102c or 202a, 202b, 202c of these buffer layers 112, 212 have different compositions from each other. In addition, it contains Ga which is the main component metal element contained the most among the metal elements contained in the above-mentioned crystalline oxide semiconductor films 103, 203. At this time, further, it can also contain the main component metal element contained the most among the metal elements contained in the substrate of the buffer layer. Among them, the main component metal element of the substrate of the buffer layer is Figure 2 in the Figure 3 scheme refers to the main component metal element of the substrate 101, and in the

[0127] scheme refers to the main component metal element of the peeling layer 204. The main component mentioned here refers to the component accounting for 50 to 100 atomic% in the metal component.

[0127] In addition, in the present invention, the buffer layer contains Ga as the main component, and it only needs to be composed of three or more buffer films in such a way that the composition ratio of Ga increases from the substrate side of the buffer layer to the crystalline oxide semiconductor film side, and the total number of layers and composition of the buffer films as a whole can be appropriately adjusted according to conditions such as the thickness of the crystalline oxide semiconductor film. At this time, the film thickness of at least two of the three or more buffer films is set to be 200 nm or more and 650 nm or less. The thicknesses of at least two buffer films can be the same thickness or different thicknesses, but if it is less than 200 nm, sufficient effects cannot be obtained, and in addition, if it is greater than 650 nm, the stress becomes significant, and warping and defects will be introduced. If the film thicknesses of the three or more buffer films are all 200 nm or more and 650 nm or less, it is more preferable.

[0128] In addition, the three or more buffer layers contain Ga as the main component, and it only needs to be formed in such a way that the composition ratio of Ga increases from the substrate side of the buffer layer to the crystalline oxide semiconductor film side. For example, in the Figure 2 scheme, the composition ratio of Ga increases in the order of the buffer films 102a, 102b, 102c.

[0129] When the buffer film contains the main component metal element of the substrate of the buffer layer, the buffer film can be laminated in such a way that the composition ratio of the main component metal element of the substrate of the buffer layer decreases from the substrate side to the crystalline oxide semiconductor film side. For example, when forming a crystalline oxide semiconductor film of α-Ga2O3 on an Al2O3 wafer, a buffer film can be formed as (Al x Ga 1-x )2O3 (0 < x < 1) and the value of x can be decreased from the substrate (wafer) side to the crystalline oxide semiconductor film side. As described above, by forming the crystalline oxide semiconductor film on the buffer layer where the composition changes monotonically in this way, a crystalline oxide semiconductor film with a high film formation rate, reduced stress caused by the lattice constant difference, suppressed warping and cracking, and a small in-plane distribution of film thickness can be obtained.

[0130] In addition, the composition of the buffer layer can be controlled by changing the supply ratio of each metal raw material. For example, when using the mist CVD method, it can be controlled by changing the concentration of the raw material solution, the flow rate of the carrier gas for transporting the mist, and the film formation temperature.

[0131] Furthermore, it is preferable to use a substrate in which the main component metal element contained the most among the metal elements contained in the substrate is aluminum, and it is preferable to use the substrate of the buffer layer as the substrate. This is advantageous in terms of quality and cost.

[0132] (Method for manufacturing a laminated structure)

[0133] The method for manufacturing the laminated structure of the present invention is not particularly limited. The substrate and the buffer layer can be appropriately selected according to the type of the crystalline oxide semiconductor film or the semiconductor element to be applied, and a film can be formed on the substrate to obtain a laminated structure. The film formation method is not particularly limited, and it can be achieved by a wide range of known methods such as plasma CVD, LPCVD (low-pressure CVD), APCVD (atmospheric pressure CVD), mist CVD, HVPE, sputtering, ion plating, etc., but it is preferable to use the mist CVD method for film formation. The film formation method based on the mist CVD method will be described in detail later. In addition, the formation method of the buffer layer (buffer film) is not particularly limited. A method of manufacturing by crystal growth on the substrate using mist is preferable.

[0134] (Semiconductor device)

[0135] In addition, the semiconductor device of the present invention includes at least one of the above-described crystalline oxide semiconductor film or the above-described laminated structure. For example, semiconductor devices (semiconductor elements) such as semiconductor lasers, diodes, or transistors can be provided. Such a semiconductor device may include a substrate or may remove the substrate. The semiconductor device of the present invention uses a high-quality crystalline oxide semiconductor film with good crystallinity and is a high-quality semiconductor device. Application examples (specific examples) of the semiconductor device are described below.

[0136] (Examples of applicable semiconductor devices)

[0137] As described above, the crystalline oxide semiconductor film or the laminated structure having a crystalline oxide semiconductor film has good crystallinity, excellent electrical properties, and is useful for industry. Such a crystalline oxide semiconductor film or a laminated structure having a crystalline oxide semiconductor film can be applied to various semiconductor devices, etc., and is particularly useful for power devices.

[0138] In addition, semiconductor devices can be classified into horizontal elements (horizontal devices) in which electrodes are formed on one side surface of the crystalline oxide semiconductor film and vertical elements (vertical devices) in which electrodes are respectively provided on both the inner and outer surfaces of the crystalline oxide semiconductor film. The semiconductor device of the present invention is applicable to both horizontal devices and vertical devices, but is preferably used for vertical devices. Examples of semiconductor devices include Schottky barrier diodes (SBDs), metal-semiconductor field effect transistors (MESFETs), high electron mobility transistors (HEMTs), semiconductor field effect transistors (MOSFETs), junction field effect transistors (JFETs), insulated gate bipolar transistors (IGBTs), or light-emitting diodes (LEDs), etc.

[0139] (Manufacturing method of semiconductor device)

[0140] First, a buffer layer is formed directly on the main surface of the substrate or through other layers. The buffer layer contains Ga as the main component and is formed by film formation in the following manner: it is composed of more than 3 layers of buffer films in a manner in which the composition ratio of Ga increases from the substrate side of the buffer layer to the crystalline oxide semiconductor film side, and at the same time contains more than 2 layers of buffer films with a thickness of more than 200nm and less than 650nm. It is preferred to make the multilayer buffer films constituting the buffer layer have a thickness of more than 200nm and less than 650nm for film formation. A crystalline oxide semiconductor film with α-Ga2O3 as the main component is formed on the buffer layer to obtain a stacked structure of the present invention. Then, a semiconductor device is further manufactured by forming an electrode on the crystalline oxide semiconductor film. At this time, a stacked structure comprising a substrate, a buffer layer, and a crystalline oxide semiconductor film can be used directly, or the substrate can be removed to leave the buffer layer and the crystalline oxide semiconductor film, or the substrate and the buffer layer can be removed to leave only the crystalline oxide semiconductor film. Thus, a high-performance semiconductor device using a high-quality crystalline oxide semiconductor film with good crystallinity can be manufactured.

[0141] Hereinafter, the optimal example of applying the crystalline oxide semiconductor film of the present invention to an n-type semiconductor layer (n+ type semiconductor or n- semiconductor layer, etc.) is described using the accompanying drawings, but the present invention is not limited to these examples. In addition, in the semiconductor element shown below, other layers (such as an insulator layer or a conductor layer) may be further included, and an intermediate layer or a buffer layer (buffer layer) may be appropriately omitted.

[0142] Figure 4 The SBD 300 is an example of the SBD of the present invention. The SBD 300 includes an n-type semiconductor layer 301 a doped at a relatively low concentration, an n+ type semiconductor layer 301 b doped at a relatively high concentration, a Schottky electrode 302 , and an ohmic electrode 303 .

[0143] The materials of the Schottky electrode 302 and the ohmic electrode 303 can be known electrode materials. Examples of the electrode materials include metals such as aluminum, molybdenum, cobalt, zirconium, tin, niobium, iron, chromium, tantalum, titanium, gold, platinum, vanadium, manganese, nickel, copper, hafnium, tungsten, iridium, zinc, indium, palladium, neodymium or silver, or alloys of these metals, metal oxide conductive films such as tin oxide, zinc oxide, rhenium oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), etc., organic conductive compounds such as polyaniline, polythiophene or polypyrrole, or mixtures and stacks of these materials, etc.

[0144] The formation of the Schottky electrode 302 and the ohmic electrode 303 can be carried out, for example, by a known method such as vacuum evaporation or sputtering. More specifically, for example, when forming a Schottky electrode using two of the above-mentioned metals, namely the first metal and the second metal, it can be carried out in the following manner: laminating a layer composed of the first metal and a layer composed of the second metal, and patterning the layer composed of the first metal and the layer composed of the second metal by using a photolithography method.

[0145] When a reverse bias is applied to the SBD 300, since the depletion layer (not shown) expands in the n-type semiconductor layer 301a, a high-voltage-resistant SBD is formed. In addition, when a forward bias is applied, electrons flow from the ohmic electrode 303 to the Schottky electrode 302. Therefore, the SBD of the present invention has high voltage resistance, is excellent when used for large currents, has a fast switching speed, and also has excellent voltage resistance and reliability.

[0146] Figure 5 This is an example of the HEMT of the present invention. The HEMT 400 includes an n-type semiconductor layer 401 with a wide bandgap, an n-type semiconductor layer 402 with a narrow bandgap, an n+-type semiconductor layer 403, a semi-insulating layer 404, a buffer layer 405, a gate 406, a source 407, and a drain 408.

[0147] Figure 6 This is an example of the MOSFET of the present invention. The MOSFET 500 includes an n-type semiconductor layer 501, n+-type semiconductor layers 502 and 503, a gate insulating film 504, a gate 505, a source 506, and a drain 507.

[0148] Figure 7 This is an example of the IGBT of the present invention. The IGBT 600 includes an n-type semiconductor layer 601, an n-type semiconductor layer 602, an n+-type semiconductor layer 603, a p-type semiconductor layer 604, a gate insulating film 605, a gate 606, an emitter 607, and a collector 608.

[0149] Figure 8 This is an example of the LED of the present invention. The LED 700 includes a first electrode 701, an n-type semiconductor layer 702, a light-emitting layer 703, a p-type semiconductor layer 704, a light-transmissive electrode 705, and a second electrode 706. As the material of the light-transmissive electrode, a conductive material containing an oxide of indium or titanium, etc. can be cited. More specifically, for example, In2O3, ZnO, SnO2, Ga2O3, TiO2, CeO2, or a mixed crystal of two or more of these, or a material doped in these oxides, etc. can be cited. By setting these materials by a known method such as sputtering, a light-transmissive electrode can be formed. In addition, after forming the light-transmissive electrode, thermal annealing aimed at making the light-transmissive electrode transparent can be carried out.

[0150] Examples of materials for the first electrode 701 and the second electrode 706 include metals such as aluminum, molybdenum, cobalt, zirconium, tin, niobium, iron, chromium, tantalum, titanium, gold, platinum, vanadium, manganese, nickel, copper, hafnium, tungsten, iridium, zinc, indium, palladium, neodymium, or silver, alloys of these metals, metal oxide conductive films such as tin oxide, zinc oxide, rhenium oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), organic conductive compounds such as polyaniline, polythiophene, or polypyrrole, or mixtures of these materials. The film formation method of the electrode is not particularly limited, and a method can be appropriately selected from wet methods such as printing, spraying, and coating methods, physical methods such as vacuum evaporation, sputtering, and ion plating methods, chemical methods such as CVD and plasma CVD methods, etc., in consideration of the compatibility with the above materials, and formed on the above substrate.

[0151] (Film formation apparatus)

[0152] Figure 9 An example of a film formation apparatus 800 that can be used in a film formation method such as the crystalline oxide semiconductor film of the present invention is shown. The film formation apparatus 800 has: an atomization unit 820 that atomizes the raw material solution to generate mist, a carrier gas supply unit 830 that supplies a carrier gas for transporting the mist, a film formation unit 840 that heat-treats the mist to form a film on a substrate, and a transport unit 809 that connects the atomization unit 820 and the film formation unit 840 and transports the mist using the carrier gas. In addition, the film formation apparatus 800 can control its operation by including a control unit (not shown) that controls the whole or a part of the film formation apparatus 800.

[0153] (Atomization unit)

[0154] In the atomization unit 820, the raw material solution is atomized to generate mist. As long as the raw material solution can be atomized, the atomization method is not particularly limited, and a known atomization method can be used. An atomization method based on ultrasonic vibration is preferably used. This is because this method can atomize more stably.

[0155] Figure 11An example of the above-described atomization unit 820 is shown. For example, it may include a mist generation source 804 that contains a raw material solution 804a, a container 805 filled with a medium (such as water 805a) capable of conducting ultrasonic vibrations, and an ultrasonic oscillator 806 installed on the bottom surface of the container 805. Specifically, using a support (not shown), the mist generation source 804 composed of a container containing the raw material solution 804a is housed in the container 805 containing water 805a. The ultrasonic oscillator 806 is installed at the bottom of the container 805, and the ultrasonic oscillator 806 is connected to an oscillator 816. And it is configured such that when the oscillator 816 is started, the ultrasonic oscillator 806 vibrates, and the ultrasonic waves are transmitted through the water 805a into the mist generation source 804, and the raw material solution 804a is atomized.

[0156] In addition, when forming the buffer film, the raw material solution 804a mixed with each metal raw material solution can be atomized by being housed in the mist generation source 804 of one atomization unit 820, or as Figure 11 shown in the atomization units 920a and 920b, multiple atomization units can be provided, and each metal raw material solution can be separately housed in the mist generation sources 904a and 904c of different atomization units and atomized separately. When multiple atomization units are provided, as Figure 11 shown, a mist mixer 913 for mixing the atomized respective raw material solutions can be provided, or the mist mixer 913 can be not provided and they can be separately supplied to a film formation chamber 907 (not shown).

[0157] (Carrier gas supply unit)

[0158] The carrier gas supply unit 830 has a carrier gas source 802a that supplies a carrier gas, and may include a flow rate regulating valve 803a for regulating the flow rate of the carrier gas output from the carrier gas source 802a. In addition, according to needs, a dilution carrier gas source 802b for supplying a dilution carrier gas and a flow rate regulating valve 803b for regulating the flow rate of the dilution carrier gas output from the dilution carrier gas source 802b may also be provided.

[0159] The type of the carrier gas is not particularly limited and can be appropriately selected according to the film-forming material. For example, inert gases such as oxygen, ozone, nitrogen, or argon, or reducing gases such as hydrogen or forming gas can be cited. In addition, the type of the carrier gas can be one type or two or more types. For example, a dilution gas obtained by diluting the same gas as the first carrier gas with a gas other than the first carrier gas (for example, diluted 10 times) can be further used as the second carrier gas, and air can also be used. In addition, the supply position of the carrier gas can be not only one position but also two or more positions.

[0160] The flow rate of the carrier gas is not particularly limited. For example, when film formation is performed on a substrate with a diameter of 4 inches (100 mm), it is preferably set to 1 to 80 L / minute, more preferably 4 to 40 L / minute. In addition, the flow rate of the carrier gas in the present invention is the measured value at 20°C and normal pressure. When measuring at other temperatures and pressures or measuring different types of flow rates (such as mass flow rate), the volume flow rate at 20°C and normal pressure can be converted using the gas state equation.

[0161] (Film formation section)

[0162] In the film formation section 840, the mist is heated to cause a thermal reaction, and film formation is performed on a part or all of the surface of the substrate (crystalline substrate) 810. The film formation section 840 includes, for example, a film formation chamber 807. Inside the film formation chamber 807, a substrate (crystalline substrate) 810 is provided, and a heating plate 808 for heating the substrate (crystalline substrate) 810 may be provided. The heating plate 808 may be arranged outside the film formation chamber 807 as shown in Figure 9 or may be arranged inside the film formation chamber 807. In addition, in the film formation chamber 807, an exhaust port 812 for exhaust gas may be provided at a position where it does not affect the supply of the mist to the substrate (crystalline substrate) 810.

[0163] In addition, as shown in the film formation apparatus 800A shown in Figure 10 , the film formation section 840 may include a moving mechanism 814 for moving the substrate 810. The direction of moving the substrate is not particularly limited and may be a reciprocating motion or a rotational motion. In addition, at this time, a mechanism for rotating the substrate may be further provided to rotate the substrate. By moving the substrate to supply the mist to the entire surface of the substrate, even for large-diameter substrates with a diameter of about 15 cm (6 inches), about 20 cm (8 inches), or about 30 cm (12 inches), etc., film formation can be more stably and uniformly performed on the entire surface of the substrate.

[0164] In addition, the substrate (crystalline substrate) 810 may be arranged on the upper surface of the film formation chamber 807 or the like, facing down (face-down), or the substrate (crystalline substrate) 810 may be arranged on the bottom surface of the film formation chamber 807, facing up (face-up). At this time, one substrate 810 may be placed in the film formation chamber 807, or two or more substrates may be placed. When two or more substrates are placed, they may be arranged symmetrically with respect to the mist supply port 809b for supplying the mist to the film formation chamber 807.

[0165] For the thermal reaction, it is only necessary to heat the mist to cause the reaction, and the reaction conditions and the like are not particularly limited. They can be appropriately set according to the raw materials or film-forming materials. For example, the heating temperature ranges from 120 to 600 °C, preferably from 200 to 600 °C, and more preferably set to the range of 300 to 550 °C.

[0166] The thermal reaction can be carried out under any one of the atmospheres of vacuum, non-oxygen atmosphere, reducing gas atmosphere, air atmosphere, and oxygen atmosphere, and can be appropriately set according to the film-forming material. In addition, for the reaction pressure, it can be carried out under any one of the conditions of atmospheric pressure, increased pressure, or reduced pressure. However, for film formation under atmospheric pressure, it is preferred because the device configuration can be simplified.

[0167] (Transportation section)

[0168] The transportation section 809 connects the atomization section 820 and the film-forming section 840. Through the transportation section 809, the mist is transported from the mist generation source 804 of the atomization section 820 to the film-forming chamber 807 of the film-forming section 840 by the carrier gas. For example, as Figure 9 shown, the transportation section 809 can be made into a supply pipe 809a. In addition, for example, as Figure 10 shown, a supply pipe 809a and a mist supply port 809b for supplying mist into the film-forming chamber 807 can be made. As the supply pipe 809a, for example, a quartz tube or a resin tube can be used.

[0169] (Raw material solution)

[0170] As long as it contains materials that can be atomized, the raw material solution (aqueous solution) 804a is not particularly limited and can be either an inorganic material or an organic material. Solutions of metals or metal compounds are preferably used in the raw material solution, and solutions containing one or more metals selected from gallium, iron, indium, aluminum, vanadium, titanium, chromium, rhodium, nickel, and cobalt can be used. As long as the composition and the like are set according to the above raw material solution for a Ga-based crystalline oxide semiconductor film or a buffer layer containing Al as in the present invention.

[0171] As long as the above metal solution can be atomized, the raw material solution is not particularly limited, and a solution obtained by dissolving or dispersing a metal in the form of a complex or a salt in an organic solvent or water can be appropriately used as the raw material solution. As the form of the complex, for example, acetylacetone complex, carbonyl complex, ammonia complex, hydride complex, etc. can be cited. As the form of the salt, for example, metal chloride salts, metal bromide salts, metal iodide salts, etc. can be cited. In addition, substances obtained by dissolving the above metals in hydrobromic acid, hydrochloric acid, hydroiodic acid, etc. can also be used as aqueous salt solutions. The solute concentration is preferably 0.01 to 1 mol / L.

[0172] In addition, substances containing halogens (such as hydrohalic acids) or additives such as oxidants can be mixed in the raw material solution. As the hydrohalic acid, for example, hydrobromic acid, hydrochloric acid, hydroiodic acid, etc. can be cited, and among them, hydrobromic acid or hydroiodic acid is preferred. As the oxidant, for example, peroxides such as hydrogen peroxide (H2O2), sodium peroxide (Na2O2), barium peroxide (BaO2), benzoyl peroxide (C6H5CO)2O2, hypochlorous acid (HClO), perchloric acid, nitric acid, ozone water, organic peroxides such as peracetic acid or nitrobenzene, etc. can be cited.

[0173] Furthermore, a dopant can be included in the raw material solution. The dopant is not particularly limited. For example, n-type dopants such as tin, germanium, silicon, titanium, zirconium, vanadium or niobium, or p-type dopants such as copper, silver, tin, cobalt, iridium, rhodium, etc. can be cited. The concentration of the dopant can be, for example, about 1.0×10 -9 ~1.0 mol / L, can be set to a low concentration of about 1.0×10 -7 mol / L or less, or can be set to a high concentration of about 0.01 mol / L or more.

[0174] (Substrate)

[0175] As described above, as long as film formation can be performed and the film can be supported, the substrate 810 is not particularly limited. It can be a known substrate. It can be an insulator, a conductor, a semiconductor, a single crystal, or a polycrystal. For example, polysulfone, polyethersulfone, polyphenylene sulfide, polyetherether ketone, polyimide, polyetherimide, fluororesin, metals such as iron or aluminum, stainless steel, gold, etc., silicon, sapphire, quartz, glass, gallium oxide, lithium niobate, lithium tantalate, etc. can be cited, but are not limited to these materials. In addition, a substrate in which the main component metal element contained in the metal elements contained in the substrate is aluminum is preferably used. Among them, from the aspects of quality and cost, a sapphire wafer is preferably used.

[0176] The plane orientation of the main surface of the substrate is not particularly limited. When it is a sapphire wafer, for example, main planes such as the c-plane, m-plane, a-plane, etc. can be used. In addition, it can have an offset angle with respect to the front surface. The offset angle is not particularly limited, and is preferably 0 to 15°.

[0177] The thickness of the substrate 810 is not particularly limited. From the aspect of cost, it is preferably about 200 to 800 μm. In addition, the area of the main surface of the substrate 810 can be 10 cm 2Above, it is preferably an area equivalent to a diameter of about 5 cm (2 inches) or more, more preferably a diameter of about 10 cm (4 inches) or more, and further preferably a diameter of about 15 cm (6 inches) or more. As described above, if the substrate 810 is a substrate with a large diameter, the crystalline oxide semiconductor film formed on the substrate 810 will further become a crystalline oxide semiconductor film with high quality and high productivity. In addition, the degree of freedom in device design increases. In the present invention, the shape of the substrate 810 is not particularly limited. It may be circular or may be a quadrilateral such as a square.

[0178] In the present invention, annealing treatment can be performed after film formation. The temperature of the annealing treatment is not particularly limited, and it is preferably 600 °C or lower, more preferably 550 °C or lower. This is for the stability and good crystallinity of the film. The treatment time of the annealing treatment is not particularly limited, and it is preferably 10 seconds to 10 hours, more preferably 10 seconds to 1 hour.

[0179] (Film formation method)

[0180] Hereinafter, with reference to Figure 9 、 Figure 10 An example of the film formation method of the crystalline oxide semiconductor film or the buffer layer of the present invention will be described. First, the raw material solution 804a is accommodated in the mist generating source 804 of the atomizing unit 820, the substrate (crystalline substrate) 810 is placed on the heating plate 808, and the heating plate 808 is started.

[0181] Next, the flow control valves 803a and 803b are opened, carrier gas is supplied from the carrier gas source 802a (main carrier gas) and the dilution carrier gas source 802b (dilution carrier gas) into the film formation chamber 807, the atmosphere in the film formation chamber 807 is sufficiently replaced with the carrier gas, and at the same time, the flow rate of the main carrier gas and the flow rate of the dilution carrier gas are respectively adjusted and controlled.

[0182] In the mist generation process, the ultrasonic oscillator 806 is vibrated, and the vibration is transmitted to the raw material solution 804a through the water 805a, thereby atomizing the raw material solution 804a to generate mist.

[0183] Next, in the mist transportation process of transporting the mist by the carrier gas, the mist is transported from the atomizing unit 820 to the film formation unit 840 via the transportation unit 809 by the carrier gas and introduced into the film formation chamber 807.

[0184] Next, in the film formation process, the mist is supplied to the substrate 810 placed on the heating plate 808, and heat treatment and thermal reaction are performed using the heat of the heating plate 808 in the film formation chamber 807, thereby forming a film on the substrate 810. If the Figure 10 device shown is used, it is also possible to form a film on the substrate 810 while moving the substrate 810 placed on the heating plate 808 by the substrate moving mechanism 814.

[0185] (Stripping)

[0186] The substrate 810 can be stripped from the oxide semiconductor film. The stripping method is not particularly limited and can be a known method. For example, methods such as applying physical impact for stripping, applying heat to utilize thermal stress for stripping, applying vibrations such as ultrasonic waves for stripping, performing etching for stripping, and laser stripping can be cited. Through this stripping, a crystalline oxide semiconductor film as a self-supporting film can be obtained.

[0187] Examples

[0188] In Figure 10 、 12 Examples of the film-forming apparatus used in this example are shown. In addition, although the film-forming apparatus 900A described in Figure 13 does not have the substrate moving mechanism 914 in the film-forming apparatus 900 described in Figure 12 , a crystalline oxide semiconductor film with good crystallinity that reduces the buffer layer or rotational domains and further reduces warping and cracking can also be formed using such a film-forming apparatus 900.

[0189] [Example 1]

[0190] 1. Film formation of buffer layer

[0191] First, with reference to Figure 12 , the film formation of the buffer layer (buffer film) in Example 1 will be described. In Example 1, a c-plane sapphire substrate with a diameter of 4 inches (100 mm) is used as the substrate 910, and the buffer layer is set to (α-Al x Ga 1-x )2O3 (0 < x < 1).

[0192] 1-1. Production process of raw material solution

[0193] 1 vol% of HCl is added to a solution obtained by adding gallium acetylacetonate to water, and the mixture is stirred at 60°C for 120 minutes to dissolve it, thereby preparing an aqueous solution with a concentration of 0.1 mol / L. This aqueous solution is used as the Ga raw material solution 904b. The Ga raw material solution 904b obtained in the above manner is accommodated in the mist generation source 904a. The temperature of the solution at this time is 25°C.

[0194] Next, 1 vol% of HCl is added to a solution obtained by adding aluminum acetylacetonate to water, and the mixture is stirred at 60°C for 120 minutes to dissolve it, thereby preparing an aqueous solution with a concentration of 0.1 mol / L. This aqueous solution is used as the Al raw material solution 904d. The Al raw material solution 904d obtained in the above manner is accommodated in the mist generation source 904c. The temperature of the solution at this time is 25°C.

[0195] 1-2. Heating process of the substrate

[0196] Next, a 4-inch (100 mm) c-plane sapphire substrate as the substrate 910 is placed on the heating plate 908 in the film formation chamber 907, the heating plate 908 is started, and the temperature is raised to 500 °C.

[0197] 1-3. Carrier gas supply process

[0198] Next, the flow control valves 903a, 903b, 903c, and 903d of the carrier gas supply parts 930a and 930b are opened, and oxygen as the carrier gas is supplied into the film formation chamber 907 from the carrier gas source 902a (main carrier gas of Ga), the dilution carrier gas supply source 902b (dilution carrier gas of Ga), the carrier gas source 902c (main carrier gas of Al), and the dilution carrier gas supply source 902d (dilution carrier gas of Al). The atmosphere of the film formation chamber 907 is sufficiently replaced with these carrier gases. At the same time, the flow rate of the main carrier gas of Ga is adjusted to 2 L / min, the flow rate of the dilution carrier gas of Ga is adjusted to 10 L / min, the flow rate of the main carrier gas of Al is adjusted to 10 L / min, and the flow rate of the dilution carrier gas of Al is adjusted to 2 L / min.

[0199] 1-4. Film formation process

[0200] Next, the ultrasonic oscillators 906a and 906b are vibrated at 2.4 MHz by the oscillators 916a and 916b, and the vibration is transmitted to the Ga raw material solution 904b and the Al raw material solution 904d through the water 905b and 905d in the containers 905a and 905c, thereby atomizing the Ga raw material solution 904b and the Al raw material solution 904d to generate mist.

[0201] The mist is transported to the mist mixer 913 through the transport pipes 909a and 909b by the carrier gas, and the mist of the Ga raw material solution 904b and the mist of the Al raw material solution 904d are mixed in the mist mixer 913. The mist mixed in the mist mixer 913 is transported to the film formation chamber 907 of the film formation part 940 through the supply pipe 909c of the transport part 909 by the carrier gas, and the mist is supplied onto the substrate 910.

[0202] Next, the gas is discharged from the exhaust port 912 under atmospheric pressure and at a temperature of 500 °C, and the mist undergoes a thermal reaction in the film formation chamber 907 to form a first-layer buffer film (α-Al x1 Ga 1-x1) A film of 2O3 (0 < x1 < 1). At this time, through the substrate moving mechanism 914, with the mist supply port 909d as the center, while the substrate is reciprocally moved at a speed of 2.5 mm / second within a width of 150 mm, film formation is carried out. The film formation time is set to 60 minutes. At this time, a liquid replenishing mechanism (not shown) is appropriately used to replenish the raw material solutions 904b of Ga and 904d of Al into the mist generation sources 904a and 904b, so that the water surface heights of the raw material solution 904b of Ga in the mist generation source 904a and the raw material solution 904d of Al in the mist generation source 904c are constant during film formation.

[0203] Next, the flow rates of the carrier gases in the above "1 - 3. Carrier gas supply process" are respectively adjusted. The flow rate of the main carrier gas of Ga is adjusted to 4 L / minute, the flow rate of the dilution carrier gas of Ga is adjusted to 8 L / minute, the flow rate of the main carrier gas of Al is adjusted to 8 L / minute, and the flow rate of the dilution carrier gas of Al is adjusted to 4 L / minute. The film formation process is carried out in the same manner as above. On the first - layer buffer film (α - Al x1 Ga 1-x1 )2O3 (0 < x1 < 1), a second - layer buffer film (α - Al x2 Ga 1-x2 )2O3 (0 < x2 < x1) is formed.

[0204] Then, the flow rates of the carrier gases in the above "1 - 3. Carrier gas supply process" are respectively adjusted. The flow rate of the main carrier gas of Ga is adjusted to 6 L / minute, the flow rate of the dilution carrier gas of Ga is adjusted to 6 L / minute, the flow rate of the main carrier gas of Al is adjusted to 6 L / minute, and the flow rate of the dilution carrier gas of Al is adjusted to 6 L / minute. The "1 - 4. Film formation process" is carried out in the same manner as above. On the second - layer buffer film (α - Al x2 Ga 1-x2 )2O3 (0 < x2 < x1), a third - layer buffer film (α - Al x3 Ga 1-x3 )2O3 (0 < x3 < x2) is formed, and the formation of the buffer film is completed.

[0205] 2. Film formation of the crystalline oxide semiconductor film

[0206] Next, the film formation of the crystalline oxide semiconductor film of this Example 1 will be described with reference to Figure 10 this.

[0207] 2 - 1. Raw material solution preparation process

[0208] Gallium iodide and tin(II) chloride dihydrate were added to water in such a way that the atomic ratio of tin to gallium was 1:0.01, and the mixture was stirred at 60 °C for 60 minutes to dissolve it, preparing a 0.1 mol / L aqueous solution, which was used as the raw material solution 804a. The raw material solution 804a obtained in the above manner was accommodated in the mist generation source 804. The temperature of the solution at this time was 25 °C.

[0209] 2-2. Heating step

[0210] Next, in the film formation chamber 807, the substrate 810 on which the buffer layer was formed in the above "1. Formation of the buffer film" was placed on the heating plate 808, and the heating plate 808 was started, and the temperature was raised to 500 °C.

[0211] 2-3. Carrier gas supply step

[0212] Next, the flow control valves 803a and 803b were opened, and nitrogen gas as the carrier gas was supplied from the carrier gas source 802a (main carrier gas) and the dilution carrier gas supply source 802b (dilution carrier gas) into the film formation chamber 807, and the atmosphere of the film formation chamber 807 was partially replaced with these carrier gases. At the same time, the flow rate of the main carrier gas was adjusted to 12 L / minute, and the flow rate of the dilution carrier gas was adjusted to 12 L / minute.

[0213] 2-4. Film formation step

[0214] Next, the ultrasonic oscillator 806 was vibrated at 2.4 MHz, and this vibration was transmitted to the raw material solution 804a through the water 805a, thereby atomizing the raw material solution 804a to generate mist.

[0215] The mist was transported to the film formation chamber 807 through the supply pipe 809a by the carrier gas, and the mist was supplied to the substrate 810.

[0216] Next, gas was discharged from the exhaust port 812 under atmospheric pressure and at 500 °C, and the mist was thermally reacted in the film formation chamber 807 to form a film of α-Ga2O3 having a corundum structure on the substrate 810. At this time, using the substrate moving mechanism 814 as shown in Figure 10 while moving the substrate back and forth at 2.5 mm / second in a width of 150 mm with the mist supply port 809b as the center, film formation was carried out. The film formation time was set to 150 minutes. At this time, a replenishing mechanism (not shown) was appropriately used to replenish the raw material solution 804a into the mist generation source 804 so that the height of the water surface of the raw material solution 804a in the mist generation source 804 was constant during film formation.

[0217] (Evaluation)

[0218] 1. Film thickness measurement

[0219] For the buffer film formed on the substrate 910 and the crystalline oxide semiconductor film formed by film formation on the buffer film, 25 points in the plane on the substrate 910 were set as measurement positions, and the film thickness was measured using an optical interference type film thickness gauge F50.

[0220] At this time, a four-layer laminate with different refractive indexes was measured. As Figure 14 shown, in the polar coordinate system where the radius of the substrate is set as R, the center of the substrate is set as the origin 0, the distance from the origin 0 is set as r, and the angle formed with the x-axis is set as θ [°], the polar coordinates (r, θ) of the measurement point 1002 are (0, 0), (0.3R, θ), (0.6R, θ), (0.9R, θ), and a total of 25 points with θ [°] = 0, 45, 90, 135, 180, 225, 270, 315 were measured.

[0221] Based on each value, the average film thickness was calculated. As a result, the first layer of the buffer film was 250 nm, the second layer was 400 nm, the third layer was 550 nm, and the crystalline oxide semiconductor film was 7.6 μm.

[0222] The distribution of the film thickness at the 25 measurement positions of the crystalline oxide semiconductor film (=(maximum film thickness - minimum film thickness) / 2 / average film thickness × 100) was ±1.9%, the standard deviation was 0.07 μm, and the coefficient of variation (=standard deviation / average film thickness) was 0.009.

[0223] In addition, based on the average film thickness of each film and the film formation time, the film formation speed was calculated. As a result, the first layer of the buffer film was 4.2 nm / minute, the second layer was 6.6 nm / minute, the third layer was 9.2 nm / minute, and the crystalline oxide semiconductor film was 3 μm / hour.

[0224] Next, in order to measure the warpage, the shortest distance between the shortest straight line passing through the two ends within 5 mm and the concave vertex or convex vertex was measured. The warpage was 0.14 μm.

[0225] Next, using an optical microscope, the presence or absence of cracks within 1 mm 2 was observed. No cracks were observed within the observation range.

[0226] 2. Crystalline Structure Evaluation

[0227] XRD 2θ / ω scanning was performed on the buffer film formed on the substrate 910 and the crystalline oxide semiconductor film formed by film formation on the buffer film. As a result, a peak from the (006) plane of the sapphire substrate was observed at 2θ = 41.7°. In addition, a peak was observed at 2θ = 40.3°. It is considered to be from the (006) plane of α-Ga2O3, and it is speculated that the obtained crystalline oxide semiconductor film is α-Ga2O3.

[0228] In addition, three peaks were further observed between 2θ = 40.3° and 41.7°. These are considered to be the peaks from the (006) plane of the buffer film (α-Al x Ga 1-x )2O3 (0 < x < 1). They are considered to be the peaks of the first-layer buffer film (α-Al x1 Ga 1-x1 )2O3 (0 < x1 < 1), the second-layer buffer film (α-Al x2 Ga 1-x2 )2O3 (0 < x2 < x1), and the third-layer buffer film (α-Al x3 Ga 1-x3 )2O3 (0 < x3 < x2) in order from the high-angle side.

[0229] Next, the full width at half maximum was measured by ω-scan of the (006) plane of α-Ga2O3, and the result was 8.6 s. It was confirmed that high-quality α-Ga2O3 was fabricated.

[0230] 3. Rotation domain evaluation

[0231] (1) Out-of-Plane XRD 2θ / ω scan

[0232] Using an X-ray diffractometer (SmartLab manufactured by Rigaku Corporation), an Out-of-Plane XRD 2θ / ω scan measurement was performed on the (104) plane of the buffer film formed on the substrate 910 and the crystalline oxide semiconductor film formed on the buffer film. Since the (104) plane is inclined by about 38° with respect to the c-axis direction, the χ-axis was operated and the measurement was performed with the sample tilted. In addition, the measurement conditions are shown below.

[0233] · Measuring device: SmartLab (product name) manufactured by Rigaku Corporation

[0234] · Analysis conditions

[0235] Measurement method: Out-of-Plane XRD method (2θ / ω scan)

[0236] X-ray generation part: Anticathode Cu

[0237] : Output 45 kV 200 mA

[0238] Detection part: Semiconductor detector

[0239] Incident optical system: Ge(220) channel-cut monochromator

[0240] Soller slit: Incident side -

[0241] : Light-receiving side: 5.0°

[0242] Slit: Incident side IS = 1 (mm)

[0243] : Length limit: 0.5 (mm)

[0244] : Light-receiving side RS1 = 1 RS2 = 1.1 (mm)

[0245] Scanning conditions: Scanning axis 2θ / ω

[0246] : Scanning mode: Stepwise measurement

[0247] : Scanning range: 30~38°

[0248] : Step size: 0.005°

[0249] : Accumulation time: 0.5 sec. / step

[0250] (2) ω-scanning

[0251] Using the 2θ fixed diffraction angle of the peak obtained in the above (1), ω-scanning is performed. The full width at half maximum of the rocking curve of the (104) plane is 1321 s. In addition, the measurement conditions are shown below.

[0252] · Measuring device: SmartLab (product name) manufactured by Rigaku Corporation

[0253] · Analysis conditions

[0254] Measurement method: Rocking curve measurement (ω-scanning)

[0255] X-ray generation section: Anticathode Cu

[0256] : Output: 45 kV 200 mA

[0257] Detection section: Semiconductor detector

[0258] Incident optical system: Ge(220) channel-cut monochromator

[0259] Soller slit: Incident side -

[0260] : Light-receiving side: 5.0°

[0261] Slit: Incident side IS = 1 (mm)

[0262] : Length limit: 0.5 (mm)

[0263] : Light-receiving side RS1 = 1 RS2 = 1.1 (mm)

[0264] Scanning conditions: Evaluate the diffraction plane Ga2O3(104)

[0265] : Scanning axis ω

[0266] : Scanning mode Step determination

[0267] : Scanning range 13~21°

[0268] : Step size 0.005°

[0269] : Accumulation time 0.5 sec. / step

[0270] (3) φ scanning

[0271] Fix 2θ and ω at the peak positions obtained in the above (2), and perform φ scanning of the (104) plane by rotating the φ axis parallel to the specimen surface normal. The content ratio of the rotating domain is calculated by (content ratio of rotating domain [%]) = C2 / C1×100 using the total area (C1) of the peaks appearing in the φ scanning and the total area (C2) of the peaks of the rotating domain. As Figure 1 shown, in the φ scanning of this Example 1, only peaks of three-fold symmetry at approximately 89°, approximately 209°, and approximately 329° were observed, and peaks of three-fold symmetry from the rotating domain at approximately 29°, approximately 149°, and approximately 269° were not observed. Therefore, as shown in Table 1 below, the content ratio of the rotating domain [%] is 0% (= 0 / 3.81×10 7 ×100). In addition, the count of the highest intensity of the peaks of the rotating domain is 0 count relative to the count of the peak of the highest intensity in the φ scanning, which is 343,375 counts.

[0272] Next, for the measurements in the above (1) to (3), as Figure 14 shown, in the polar coordinate system where the radius of the crystalline oxide semiconductor film 1001 formed on the substrate 1000 is R, the center of the crystalline oxide semiconductor film 1001 is the origin 0, the distance from the origin 0 is r, and the angle formed with the x-axis is θ, measurements are performed at a total of 5 positions of polar coordinates (r,θ) = (0,0), (0.5R,0), (0.5R,90), (0.5R,180), and (0.5R,270). In this Example, since the substrate size is 4 inches (100 mm), R = 50 mm, and the measurement positions are 5 points of (r,θ) = (0,0), (25,0), (25,90), (25,180), and (25,270). Peaks from the rotating domain were not detected at any of the 5 measured points, and it can be seen that the content ratio of the rotating domain is 0%. In addition, Figure 1 is the result for the measurement point (0,0). In addition, the following shows the measurement conditions.

[0273] (X-ray measurement conditions: φ scan)

[0274] Measurement method: rocking curve measurement (φ scan)

[0275] X-ray generation section: anticathode Cu

[0276] : Output 45 kV 200 mA

[0277] Detection section: semiconductor detector

[0278] Incident optical system: Ge(220) channel cut monochromator

[0279] Soller slit: incident side -

[0280] : light-receiving side 5.0°

[0281] Slit: incident side IS = 1 (mm)

[0282] : length limit 0.5 (mm)

[0283] : light-receiving side RS1 = 1 RS2 = 1.1 (mm)

[0284] Scanning conditions: evaluation diffraction plane Ga2O3(104)

[0285] : scanning axis φ

[0286] : scanning mode continuous scan

[0287] : scanning range 0~360°

[0288] : step size 0.02°

[0289] : scanning speed 12° / min

[0290] [Comparative Example 1]

[0291] Except that "1. Film formation of the buffer layer" was not performed and the film formation time in "2-4. Film formation process" was set to 240 minutes, film formation was carried out in the same manner as in Example 1. Evaluation was carried out in the same manner as in Example 1. As a result, the film thickness of the crystalline oxide semiconductor film was 6.0 μm, and the film formation speed of the crystalline oxide semiconductor film was 1.5 μm / hour.

[0292] The distribution of the film thickness at 25 points of the measurement position of the crystalline oxide semiconductor film (=(maximum film thickness - minimum film thickness) / 2 / average film thickness × 100) was ±7.1%, the standard deviation was 0.22 μm, and the coefficient of variation (=standard deviation / average film thickness) was 0.037. In addition, the warpage was 0.34 μm, and numerous cracks were observed in the plane.

[0293] Evaluation by XRD revealed the formation of α-Ga2O3. In addition, the full width at half maximum (FWHM) of the rocking curve for the (006) plane was 40.1 s, and that for the (104) plane was 3544 s. Further, φ-scanning of the (104) plane was performed, and the results are as shown in Figure 15 . In addition to the three-fold symmetric peaks at approximately 89°, approximately 209°, and approximately 329°, peaks from rotational domains with three-fold symmetry were observed at approximately 29°, approximately 149°, and approximately 269°. The content ratio of the rotational domains was calculated, and the result was 1.95% (= 1.56×10 4 / 7.99×10 5 ×100). In addition, Figure 15 This is the result for the measurement point (0,0). However, in the polar coordinate system shown in Figure 14 , peaks of rotational domains were observed at a total of five positions with polar coordinates (r,θ) = (0,0), (0.5R,0), (0.5R,90), (0.5R,180), and (0.5R,270). The maximum value among the five positions was 3.28%, and the minimum value was 1.24%. In addition, the median value of the five points was 1.95%. At the point where the content ratio of the smallest rotational domains was 1.24%, with respect to the total peak area of 798,699 counts, the rotational domains were 9,903 counts, which is the ratio of 13,400 counts to 1,000,000 counts. In addition, the average value of the five points was 2.1, the variance given by the sum of the squares of the differences between the average value and each value was 0.55, the standard deviation, which is the square root of the variance, was 0.74, and the coefficient of variation represented by the quotient of the standard deviation and the average value was 0.35.

[0294] In addition, the count of the highest intensity of the peak of the rotational domains was 332 counts with respect to the count of the peak with the highest intensity in the φ-scanning, which was 14,983 counts.

[0295] [Example 2]

[0296] A 6-inch (150 mm) sapphire substrate was used as the substrate. The flow rate of each gas was doubled. The substrate was reciprocally moved at a speed of 2.5 mm / second within a width of 200 mm centered on the mist supply port 909d by the substrate moving mechanism 914 while film formation was carried out. Other than this, the buffer layer was formed in the same manner as in Example 1. Then, germanium oxide was used instead of tin(II) chloride dihydrate in the "2-1. Raw material solution preparation process", and a 0.1 mol / L gallium bromide aqueous solution was prepared such that the atomic ratio of gallium to germanium was 1:0.01. The flow rate of each gas in the "2-3. Carrier gas supply process" was doubled. The film formation time in the "2-4. Film formation process" was set to 120 minutes. The substrate was reciprocally moved at a speed of 2.5 mm / second within a width of 200 mm centered on the mist supply port 809b by the substrate moving mechanism 814 while film formation was carried out. Other than this, film formation was carried out in the same manner as in Example 1.

[0297] Evaluation was carried out in the same manner as in Example 1. As a result, the film thickness of the crystalline oxide semiconductor film was 5.1 μm, and the film formation rate of the crystalline oxide semiconductor film was 2.6 μm / hour. The distribution of the film thickness at 25 points at the measurement position of the crystalline oxide semiconductor film (=(maximum film thickness - minimum film thickness) / 2 / average film thickness × 100) was ±3.6%, the standard deviation was 0.08 μm, and the coefficient of variation (=standard deviation / average film thickness) was 0.016. In addition, the warp was 0.15 μm. In addition, within 1 mm 2 no cracks were observed.

[0298] It was found from the evaluation by XRD that α-Ga2O3 was formed. In addition, the full width at half maximum of the rocking curve of the (006) plane was 15.1 s, and the full width at half maximum of the rocking curve of the (104) plane was 1726 s. Further, φ scanning of the (104) plane was carried out. As a result, Figure 1 the same as 6 only three-fold symmetric peaks at approximately 89°, approximately 209°, and approximately 329° were observed. The content rate of the rotational domain was calculated. As a result, it was 0% (=0 / 3.80×10 Figure 14 ×100). In the polar coordinate system shown in

[0299] [Example 3]

[0300] An 8-inch (150 mm) sapphire substrate was used as the substrate. The flow rate of each gas was set to 4 times. The substrate was reciprocally moved at 2.5 mm / second over a width of 250 mm with the mist supply port 909d as the center by the substrate moving mechanism 914 while film formation was carried out. Except for this, the buffer layer was formed in the same manner as in Example 1. Then, in the "2-1. Raw material solution preparation process", chloro(2-cyanoethyl)dimethylsilane (ClSi(CH3)2((CH2)2CN)) was used instead of tin(II) chloride dihydrate, and a 0.1 mol / L aqueous solution of gallium acetylacetonate containing 1 vol% hydrochloric acid was prepared such that the atomic ratio of gallium to Si was 1:0.01 and used as the raw material solution 804a. The flow rate of each gas in the "2-3. Carrier gas supply process" was set to 4 times. The film formation time in the "2-4. Film formation process" was set to 210 minutes. The substrate was reciprocally moved at 2.5 mm / second over a width of 250 mm with the mist supply port 809b as the center by the substrate moving mechanism 814 while film formation was carried out. Except for this, film formation was carried out in the same manner as in Example 1.

[0301] Evaluation was carried out in the same manner as in Example 1. As a result, the film thickness of the crystalline oxide semiconductor film was 10.0 μm, and the film formation rate of the crystalline oxide semiconductor film was 2.9 μm / hour. The distribution of the film thickness at 25 points at the measurement position of the crystalline oxide semiconductor film (=(maximum film thickness - minimum film thickness) / 2 / average film thickness × 100) was ±2.7%, the standard deviation was 0.12 μm, and the coefficient of variation (=standard deviation / average film thickness) was 0.012. In addition, the warpage was 0.15 μm. In addition, within 1 mm 2 no cracks were observed.

[0302] It was found from the evaluation by XRD that α-Ga2O3 was formed. In addition, the full width at half maximum of the (006) plane was 9.8 s, and the full width at half maximum of the rocking curve of the (104) plane was 1283 s. Further, φ scanning of the (104) plane was carried out. As a result, the same as Figure 1 only three-fold symmetric peaks at approximately 89°, approximately 209°, and approximately 329° were observed. The content rate of the rotational domain was calculated. As a result, it was 0% (=0 / 3.54×10 7 ×100). In the Figure 14 polar coordinate system shown, no rotational domain peaks were observed at a total of 5 positions of polar coordinates (r,θ)=(0,0), (0.5R,0), (0.5R,90), (0.5R,180), and (0.5R,270). In addition, the count of the highest intensity of the rotational domain peak was 0 count relative to the count of the highest intensity peak of the φ scan, which was 305,301 counts.

[0303] [Comparative Example 2]

[0304] In "1. Film formation of the buffer layer", the buffer film of the third layer (α-Al x3 Ga 1-x3 )2O3 (x3 < x2 < 1) is not formed into a film, and only the (α-Al x1 Ga 1-x1 )2O3 (0 < x1 < 1) of the first layer and the (α-Al x2 Ga 1-x2 )2O3 (0 < x2 < x1) of the second layer are formed into a film (i.e., there are 2 layers in the buffer layer). The film formation time is set to 30 minutes, and the film formation time in "2-4. Film formation process" is set to 240 minutes. Except for this, film formation is carried out in the same manner as in Example 1.

[0305] Evaluation is carried out in the same manner as in Example 1. As a result, the thickness of the first layer of the buffer film is 130 nm, the second layer is 200 nm, the thickness of the crystalline oxide semiconductor film is 6.4 μm, and the film formation speed of the crystalline oxide semiconductor film is 1.6 μm / hour. The distribution of the film thickness at 25 points at the measurement position of the crystalline oxide semiconductor film (=(maximum film thickness - minimum film thickness) / 2 / average film thickness × 100) is ±6.5%, the standard deviation is 0.21 μm, and the coefficient of variation (=standard deviation / average film thickness) is 0.033. In addition, the warpage is 0.25 μm, and numerous cracks are observed in the plane.

[0306] It can be known from the evaluation by XRD that α-Ga2O3 is formed. In addition, the full width at half maximum of the (006) plane is 25.1 s, and the full width at half maximum of the rocking curve of the (104) plane is 2542 s. Further, φ scanning of the (104) plane is carried out. As a result, in addition to the three-fold symmetric peaks at about 89°, about 209°, and about 329°, three-fold symmetric peaks from the rotational domains are very weakly observed at about 29°, about 149°, and about 269°. The content ratio of the rotational domains is calculated. As a result, it is 0.005% (=1.25×10 2 / 2.50×10 7 ×100). In the Figure 14 shown polar coordinate system, the peaks of the rotational domains are observed at a total of 5 positions of polar coordinates (r,θ)=(0,0), (0.5R,0), (0.5R,90), (0.5R,180), and (0.5R,270). For the content ratio of the rotational domains, the maximum value at the 5 positions is 0.007%, and the minimum value is 0.002%. In addition, the median value of the 5 points is 0.005%. At the point with the minimum value of 0.002%, relative to 25,014,264 counts, the rotational domains are 500 counts, which is the ratio of 20 counts to 1,000,000 counts.

[0307] In addition, the average value of 5 points is 0.005, and the variance given by the sum of the squares of the differences between the average value and each value is 3.44×10 -6 , the standard deviation, which is the square root of the variance, is 0.0018, and the coefficient of variation represented by the quotient of the standard deviation and the average value is 0.40.

[0308] In addition, the count of the highest intensity peak of the rotational domain relative to the count of the peak with the highest intensity in the φ scan is 210 counts relative to 141,426 counts.

[0309] [Example 4]

[0310] Film formation was carried out in the same manner as in Example 1, except that the film formation time was set to 30 minutes in "1. Film formation of the buffer layer".

[0311] Evaluation was carried out in the same manner as in Example 1. As a result, the thickness of the first layer of the buffer film was 130 nm, the second layer was 200 nm, the third layer was 270 nm, the thickness of the crystalline oxide semiconductor film was 9.0 μm, and the film formation rate of the crystalline oxide semiconductor film was 3.6 μm / hour. The distribution of the film thickness at 25 points at the measurement position of the crystalline oxide semiconductor film (= (maximum film thickness - minimum film thickness) / 2 / average film thickness × 100) was ±1.8%, the standard deviation was 0.10 μm, and the coefficient of variation (= standard deviation / average film thickness) was 0.011. In addition, the warpage was 0.17 μm, and no cracks were observed in the plane.

[0312] It was found by evaluation using XRD that α-Ga2O3 was formed. In addition, the full width at half maximum of the (006) plane was 19.1 s, and the full width at half maximum of the rocking curve of the (104) plane was 1948 s. Further, φ scanning of the (104) plane was carried out. As a result, in addition to the three-fold symmetric peaks at about 89°, about 209°, and about 329°, three-fold symmetric peaks from the rotational domain were very weakly observed at about 29°, about 149°, and about 269°. The content rate of the rotational domain was calculated, and the result was 3.49×10 -4 % (= 1.78×10 2 / 3.64×10 7 ×100). In the polar coordinate system shown in Figure 14 , peaks of the rotational domain were observed at a total of 5 positions of polar coordinates (r,θ) = (0,0), (0.5R,0), (0.5R,90), (0.5R,180), and (0.5R,270). For the content rate of the rotational domain, the maximum value at the 5 positions was 4.97×10 -4 %, and the minimum value was 2.47×10 -4 %. In addition, the median value of the 5 points was 3.49×10 -4 %. At the smallest value of 2.47×10-4 The points of %, counted relative to 36,421,252, the rotation domain is 90 counts, which is the ratio of 2 counts relative to 1,000,000 counts.

[0313] In addition, the average value of 5 points is 3.53×10 -4 %, and the variance given as the sum of the squares of the differences between the average value and each value is 7.66×10 -9 , and the standard deviation, which is the square root of the variance, is 8.75×10 -5 %, and the coefficient of variation represented by the quotient of the standard deviation and the average value is 0.25.

[0314] In addition, the count of the highest intensity of the peak of the rotation domain relative to the count of the peak of the highest intensity of the φ scan is 32 counts relative to 288,301 counts.

[0315] [Table 1]

[0316]

[0317] From Table 1 and Figure 1 、 Figure 15 From the results, it can be seen that the α-Ga2O3 film of the example does not have a rotation domain, the film quality such as crystallinity is excellent, and warping and cracking are reduced. Further, according to the example, a coefficient of variation of the content rate of the rotation domain measured at 5 positions in the plane of the crystalline oxide semiconductor film can be obtained, which is smaller (less than 0.35) than that of the comparative example.

[0318] In addition, Hall effect measurements were performed on the α-Ga2O3 films of Examples 1-4 and Comparative Examples 1-2. The results are shown in Table 2 below. From the results of Table 2, it can be seen that the electrical properties of the crystalline oxide semiconductor film of the present invention are also excellent.

[0319] [Table 2]

[0320]

[0321] This specification includes the following aspects.

[0322] [1]: A crystalline oxide semiconductor film, wherein the crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component, and the total area (C2) of the peaks of the rotation domain obtained by φ scan of the asymmetric plane of the crystalline oxide semiconductor film by X-ray diffraction relative to the total area (C1) of the peaks of the crystalline oxide semiconductor film is: relative to 1,000,000 counts of the total area (C1) of the peaks of the crystalline oxide semiconductor film, the total area (C2) of the peaks of the rotation domain is less than 5 counts.

[0323] [2]: The crystalline oxide semiconductor film according to [1] above, wherein, with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film being 1,000,000 counts, the total area (C2) of the peaks of the rotational domains is 0 count.

[0324] [3]: A crystalline oxide semiconductor film, wherein the crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component, and the total area (C2) of the peaks of the rotational domains obtained by φ-scan in X-ray diffraction measurement of the asymmetric plane of the crystalline oxide semiconductor film with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film being 500,000 counts, the total area (C2) of the peaks of the rotational domains is 0 count.

[0325] [4]: The crystalline oxide semiconductor film according to any one of [1] to [3] above, wherein the crystalline oxide semiconductor film contains a dopant.

[0326] [5]: The crystalline oxide semiconductor film according to any one of [1] to [4] above, wherein the film thickness of the crystalline oxide semiconductor film is 1 μm or more.

[0327] [6]: The crystalline oxide semiconductor film according to any one of [1] to [5] above, wherein, among the metals contained in the crystalline oxide semiconductor film, Ga is 90 atomic % or more.

[0328] [7]: The crystalline oxide semiconductor film according to any one of [1] to [6] above, wherein the crystalline oxide semiconductor film has a size of 2 inches (50 mm) or more in diameter.

[0329] [8]: The crystalline oxide semiconductor film according to any one of [1] to [7] above, wherein the crystalline oxide semiconductor film has a size of 6 inches (150 mm) or more in diameter.

[0330] [9]: The crystalline oxide semiconductor film according to any one of [1] to [8] above, wherein the full width at half maximum of the rocking curve of the plane parallel to the main plane of the crystalline oxide semiconductor film is 25 arcseconds or less, and the full width at half maximum of the rocking curve of the asymmetric plane is 2500 arcseconds or less.

[0331]

[10] : The crystalline oxide semiconductor film according to any one of [1] to [9] above, wherein the crystalline oxide semiconductor film has a c-plane as the main plane.

[0332]

[11] : The crystalline oxide semiconductor film according to

[10] above, wherein the full width at half maximum of the rocking curve of the (006) plane of the crystalline oxide semiconductor film is 25 arcseconds or less.

[0333]

[12] : The crystalline oxide semiconductor film according to

[10] or

[11] above, wherein the full width at half maximum of the rocking curve of the (104) plane of the crystalline oxide semiconductor film is 2500 arcseconds or less.

[0334]

[13] : The crystalline oxide semiconductor film according to any one of [1] to

[12] above, wherein the number of cracks per 1 mm 2 of the crystalline oxide semiconductor film is 0.

[0335]

[14] : The crystalline oxide semiconductor film according to any one of [1] to

[13] above, wherein the content rate [%] of the rotational domain calculated by using the total peak area (C1) of the crystalline oxide semiconductor film and the total peak area (C2) of the peak of the rotational domain and C1 / C2×100 is less than 0.0005%.

[0336]

[15] : The crystalline oxide semiconductor film according to

[14] above, wherein in the measurement at 5 positions in the plane of the crystalline oxide semiconductor film, the content rate of the rotational domain is less than 0.0005% in all cases.

[0337]

[16] : The crystalline oxide semiconductor film according to

[14] or

[15] above, wherein the coefficient of variation of the content rate of the rotational domain measured at 5 positions in the plane of the crystalline oxide semiconductor film is less than 0.35.

[0338]

[17] : The crystalline oxide semiconductor film according to any one of [1] to

[16] above, wherein the content rate [%] of the rotational domain calculated by using the total peak area (C1) of the peak of the crystalline oxide semiconductor film and the total peak area (C2) of the peak of the rotational domain and C1 / C2×100 is less than 0.0002%.

[0339]

[18] : The crystalline oxide semiconductor film according to

[17] above, wherein in the measurement at 5 positions in the plane of the crystalline oxide semiconductor film, the content rate of the rotational domain is less than 0.0002% in all cases.

[0340]

[19] : The crystalline oxide semiconductor film according to any one of [1] to

[18] above, wherein in the peaks obtained by φ scan by X-ray diffraction measurement on the asymmetric plane of the crystalline oxide semiconductor film, the count of the peak with the highest intensity among the peaks of the rotational domain is 0 count with respect to 150,000 counts of the peak with the highest intensity.

[0341]

[20] : A stacked structure formed by laminating a substrate and a crystalline oxide semiconductor film on the substrate with a buffer layer interposed therebetween, wherein the buffer layer contains Ga as a main component and is a stacked structure of three or more buffer films laminated in such a manner that the composition ratio of Ga increases from the substrate side of the buffer layer toward the crystalline oxide semiconductor film side. The film thickness of at least two of the buffer films in the buffer layer is 200 nm or more and 650 nm or less. The substrate has a corundum structure, and the crystalline oxide semiconductor film is the crystalline oxide semiconductor film according to any one of [1] to

[19] above.

[0342]

[21] : The stacked structure according to

[20] above, wherein the film thickness of all of the buffer films in the buffer layer is 200 nm or more and 650 nm or less.

[0343]

[22] : The stacked structure according to

[20] or

[21] above, wherein the buffer layer contains Al and is a stacked structure of three or more buffer films laminated in such a manner that the composition ratio of Al decreases from the substrate side of the buffer layer toward the crystalline oxide semiconductor film side.

[0344]

[23] : A semiconductor device, characterized by including at least one of the crystalline oxide semiconductor films according to any one of [1] to

[19] above or the stacked structures according to any one of

[20] to

[22] above.

[0345]

[24] : The semiconductor device according to

[23] above, wherein the semiconductor device is any one of a semiconductor laser, a diode, or a transistor.

[0346] In addition, the present invention is not limited by the above embodiments. The above embodiments are illustrative, and technical solutions having the same constitution as the technical concept described in the claims of the present invention and achieving the same effects are all included in the technical scope of the present invention.

Claims

1. A crystalline oxide semiconductor film, characterized in that: The crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component. The total area (C2) of the peaks of the rotational domains obtained by φ scanning by X-ray diffraction of the asymmetric plane of the crystalline oxide semiconductor film with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film being 1,000,000 counts, the total area (C2) of the peaks of the rotational domains is less than 5 counts.

2. The crystalline oxide semiconductor film according to claim 1, wherein With respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film being 1,000,000 counts, the total area (C2) of the peaks of the rotational domains is 0 count.

3. A crystalline oxide semiconductor film, characterized in that: The crystalline oxide semiconductor film is a uniaxially oriented film containing α-Ga2O3 as a main component. The total area (C2) of the peaks of the rotational domains obtained by φ scanning by X-ray diffraction of the asymmetric plane of the crystalline oxide semiconductor film with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film is: with respect to the total area (C1) of the peaks of the crystalline oxide semiconductor film being 500,000 counts, the total area (C2) of the peaks of the rotational domains is 0 count.

4. The crystalline oxide semiconductor film according to claim 1, wherein, The crystalline oxide semiconductor film contains a dopant.

5. The crystalline oxide semiconductor film according to claim 1, wherein The film thickness of the crystalline oxide semiconductor film is 1 μm or more.

6. The crystalline oxide semiconductor film according to claim 1, wherein Among the metals contained in the crystalline oxide semiconductor film, Ga is 90 atomic % or more.

7. The crystalline oxide semiconductor film according to claim 1, wherein The crystalline oxide semiconductor film has a size of 2 inches (50 mm) or more in diameter.

8. The crystalline oxide semiconductor film according to claim 1, wherein, The crystalline oxide semiconductor film has a size of 6 inches (150 mm) or more in diameter.

9. The crystalline oxide semiconductor film according to claim 1, wherein The full width at half maximum of the rocking curve of the plane parallel to the main plane of the crystalline oxide semiconductor film is 25 arcseconds or less, and the full width at half maximum of the rocking curve of the asymmetric plane is 2500 arcseconds or less.

10. The crystalline oxide semiconductor film according to claim 1, wherein, The crystalline oxide semiconductor film has the c-plane as the main plane.

11. The crystalline oxide semiconductor film according to claim 10, wherein, The full width at half maximum of the rocking curve of the (006) plane of the crystalline oxide semiconductor film is 25 arcseconds or less.

12. The crystalline oxide semiconductor film according to claim 10, wherein The full width at half maximum of the rocking curve of the (104) plane of the crystalline oxide semiconductor film is 2500 arcseconds or less.

13. The crystalline oxide semiconductor film according to claim 1, wherein, The number of cracks per 1 mm of the crystalline oxide semiconductor film is 0. 2 ​ 14. The crystalline oxide semiconductor film according to claim 1, wherein The content rate [%] of the rotational domains calculated for the crystalline oxide semiconductor film based on the total area (C1) of the peaks of the crystalline oxide semiconductor film and the total area (C2) of the peaks of the rotational domains and using C1 / C2×100 is less than 0.0005%.

15. The crystalline oxide semiconductor film according to claim 14, wherein In the measurement at 5 positions in the plane of the crystalline oxide semiconductor film, the content rate of the rotational domains is less than 0.0005% for all.

16. The crystalline oxide semiconductor film according to claim 14, wherein, The coefficient of variation of the content rate of the rotational domains measured at 5 positions in the plane of the crystalline oxide semiconductor film is less than 0.

35.

17. The crystalline oxide semiconductor film according to claim 1, wherein The content rate [%] of the rotational domains calculated for the crystalline oxide semiconductor film based on the total area (C1) of the peaks of the crystalline oxide semiconductor film and the total area (C2) of the peaks of the rotational domains and using C1 / C2×100 is less than 0.0002%.

18. The crystalline oxide semiconductor film according to claim 17, wherein, In the measurement at five positions in the plane of the crystalline oxide semiconductor film, the content rate of the rotational domains is less than 0.0002%.

19. The crystalline oxide semiconductor film according to claim 1, wherein Among the peaks obtained by φ scanning through X-ray diffraction of the asymmetric plane of the crystalline oxide semiconductor film, the count of the peak with the highest intensity in the rotational domain peaks is 0 count with respect to the count of 150,000 counts of the peak with the highest intensity.

20. A stacked structure formed by laminating a substrate and a crystalline oxide semiconductor film on the substrate with a buffer layer therebetween, characterized in that the buffer layer contains Ga as a main component and is a stacked structure of three or more buffer films laminated in such a manner that the composition ratio of Ga increases from the substrate side of the buffer layer toward the crystalline oxide semiconductor film side, the film thickness of at least two of the buffer films in the buffer layer is 200 nm or more and 650 nm or less, the substrate has a corundum structure, and the crystalline oxide semiconductor film is the crystalline oxide semiconductor film according to claim 1.

21. The laminated structure according to claim 20, characterized in that, The film thickness of all of the buffer films in the buffer layer is 200 nm or more and 650 nm or less.

22. The laminated structure according to claim 20, wherein, The buffer layer contains Al and is laminated with three or more buffer films in such a manner that the composition ratio of Al decreases from the substrate side of the buffer layer toward the crystalline oxide semiconductor film side.

23. A semiconductor device, characterized in that, It includes at least one of the crystalline oxide semiconductor films according to any one of claims 1 to 19 or the stacked structures according to any one of claims 20 to 22.

24. The semiconductor device according to claim 23, wherein, The semiconductor device is any one of a semiconductor laser, a diode, or a transistor.

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