Stacked structure and electronic device

Abstract

The present application provides a laminated structure (10) having a substrate (11) and a buffer film (12) formed on the substrate (11). The substrate (11) is composed of a Si substrate or an SOI substrate including a base composed of a Si substrate, an insulating layer on the base, and an SOI layer composed of a Si film on the insulating layer. The buffer film (12) is composed of a first metal oxide including one or more metal elements selected from among Group 4 elements and one or more metal elements selected from among Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements, the first metal oxide being in (111) orientation when expressed in pseudo-cubic crystal.

Description

Technical Field

[0001] This invention relates to laminated structures and electronic devices. Background Technology

[0002] A crystalline film with a yttrium-stabilized zirconia (YSZ) film formed on a substrate is known. Japanese Patent Application Publication No. 2015-025166 (Patent Document 1) discloses a technique in which a crystalline film formed on a substrate having a (100) crystalline plane comprises: a Zr film, and a stacked film or YSZ film formed on the Zr film and having a ZrO2 film and a Y2O3 film stacked thereon, wherein the half-width at half-maximum (FWHM) of the diffraction peaks of the stacked film or YSZ film evaluated by X-ray diffraction is 0.05° to 2.0°. In the technique described in Patent Document 1, the stacked film or YSZ film is a (100) oriented film, a (100) oriented Pt film is formed on the stacked film or YSZ film, and a (001) oriented PZT film is formed on the Pt film.

[0003] Furthermore, a film structure having a substrate and a piezoelectric film containing aluminum nitride (AlN) formed on the substrate, and an electronic device having the film structure are known. International Publication No. 2023 / 171108 (Patent Document 2) discloses a technology in which, in a film structure having a substrate, a buffer film containing ZrO2 formed on the substrate, and a piezoelectric film formed on the buffer film, the substrate is a Si substrate, or an SOI substrate comprising a substrate made of Si substrate, an insulating layer on the substrate, and an SOI layer made of Si film on the insulating layer, wherein the polarization direction of the piezoelectric film is preferably perpendicular to the substrate orientation.

[0004] Furthermore, the miniaturization and high integration of metal-oxide-semiconductor field-effect transistors (MOSFETs), as semiconductor devices, are constantly developing. Japanese Patent Application Publication No. 2004-281594 (Patent Document 3) discloses a technology in which a field-effect transistor includes: a semiconductor substrate, a first crystalline metal oxide layer formed on the semiconductor substrate with a lattice spacing different from that of the semiconductor substrate, a strained semiconductor layer formed on the first crystalline metal oxide layer to form a channel region, a gate insulating film and a gate electrode formed on the channel region, and a source-drain region formed on the side of the channel region.

[0005] Japanese Patent Application Publication No. 2005-005556 (Patent Document 4) discloses a technology in which a gate electrode having a gate insulating film formed on a substrate and comprising a Si film and a SiGe film is provided on the uppermost layer of the gate insulating film, and a SiGe film is formed on the oxide film of the transition metal.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2015-025166;

[0009] Patent Document 2: International Publication No. 2023 / 171108;

[0010] Patent document 3: Japanese Patent Application Publication No. 2004-281594;

[0011] Patent document 4: Japanese Patent Application Publication No. 2005-005556.

[0012] Non-patent literature

[0013] Non-patent literature 1: Chemical Society of Japan, ed., Basic Chemistry Handbook, 5th revised edition, Maruzen Publishing Co., Ltd., February 2004, p. II-291. Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] In the technology described in the aforementioned Patent Document 1, the crystalline film formed on a Si substrate having a (100) crystalline surface includes: a Zr film, and a stacked film or YSZ film on which a ZrO2 film and a Y2O3 film are stacked. However, it is not possible to align the ZrO2 film (111) on a Si substrate having a (100) crystalline surface, and it is difficult to align the piezoelectric film, i.e., the dielectric film, etc., made of AlN on the ZrO2 film (0001).

[0016] In the technology described in Patent Document 2 above, the film structure comprises: a Si(111) substrate, a buffer film containing ZrO2 formed on the Si(111) substrate and oriented in (111), a Pt layer formed on the buffer film and oriented in (111), and a piezoelectric film composed of AlN formed on the Pt layer and oriented in (0001). Here, AlN has a hexagonal crystal structure. However, when forming an AlN film oriented in (0001) on a Si substrate having a different plane orientation than that of the Si(111) substrate, such as a Si(100) substrate, with a ZrO2 film in between, it is difficult to form a piezoelectric film, i.e., a dielectric film, etc., composed of an AlN film having the same quality as the AlN film formed on the Si(111) substrate with a ZrO2 film in between.

[0017] Furthermore, YSZ is a material in which Y2O3 is added to ZrO2 as a stabilizer. However, in the technology described in Patent Document 1 above, when a dielectric film or conductive film with a cubic, tetragonal, or monoclinic crystal structure is oriented as a pseudocubic crystal on a Si substrate having a (100) or (111) crystal plane, it is preferable to use a material that is more stable and easier to control the orientation of the dielectric film than conventional YSZ. However, it is difficult to use a material that is more stable and easier to control the orientation of the dielectric film or conductive film than conventional YSZ.

[0018] In the technology described in Patent Document 3 above, after depositing La2O3, a metal oxide, onto a Si substrate with a (001) plane orientation and transforming it into a crystalline substance of La2O3 single crystal, the Si, which serves as the channel layer, is epitaxially grown, or a SiGe layer is formed on the Si substrate, or a SiGe layer is stacked with an oxide film in between. However, the crystallinity of the Si film or SiGe film formed on the silicon substrate with an oxide film in between is insufficient.

[0019] Furthermore, in the technology described in Patent Document 4 above, the semiconductor device includes: a gate insulating film formed on a silicon substrate and composed of an HfO2 film or a ZrO2 film, and a gate electrode formed on the gate insulating film and composed of a Si film or a SiGe film. Moreover, when the gate electrode is composed of a polycrystalline Si film or a polycrystalline SiGe film, compared to when the gate electrode is composed of an amorphous Si film or an amorphous SiGe film, conductive impurities (e.g., boron) implanted into the gate electrode in subsequent processes can be efficiently thermally diffused along the grain boundaries, reducing the thermal history of subsequent processes and improving the leakage current characteristics or long-term reliability of the gate insulating film. However, the Si film or SiGe film formed on the silicon substrate through an oxide film has insufficient crystallinity.

[0020] The object of the present invention is to provide a stacked structure capable of improving the crystallinity of a dielectric film, conductive film, or semiconductor film formed on a Si substrate, and an electronic device having the stacked structure. Specifically, the object of the present invention is to provide a stacked structure and an electronic device having the stacked structure, which has a buffer film formed on a Si substrate. Even if a dielectric film or conductive film with a hexagonal crystal structure, or a dielectric film or conductive film with a cubic, tetragonal, or monoclinic crystal structure is formed on the buffer film, the dielectric film or conductive film with a hexagonal crystal structure can be easily oriented (0001) regardless of the plane orientation of the Si substrate, or the dielectric film or conductive film with a cubic, tetragonal, or monoclinic crystal structure can be easily oriented (100) or (111) when represented as a pseudocubic crystal.

[0021] Alternatively, the present invention aims to provide a stacked structure and an electronic device having the stacked structure, having a semiconductor film formed on a Si substrate with a metal oxide film in between, which can improve the crystallinity of the Si film or SiGe film formed on the silicon substrate with an oxide film in between.

[0022] Methods for solving problems

[0023] [1] A laminated structure having a substrate and a first buffer film formed on the substrate,

[0024] The aforementioned substrate is composed of a Si substrate or an SOI substrate. The SOI substrate comprises: a substrate composed of a Si substrate, an insulating layer on the substrate, and an SOI layer composed of a Si film on the insulating layer.

[0025] The aforementioned first buffer film is composed of a first metal oxide, which comprises: one or more metal elements selected from Group 4 elements, and one or more metal elements selected from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements.

[0026] The first metal oxide described above is oriented in (111) when represented as a pseudocubic crystal.

[0027] [2] The laminated structure according to [1] has a second buffer film formed on the first buffer film,

[0028] The aforementioned second buffer film is composed of a second metal oxide, which contains one or more metal elements selected from Group 4 elements.

[0029] The aforementioned second metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal.

[0030] [3] According to the stacked structure described in [2], the first metal oxide has a cubic crystal structure with a (111) orientation, or has a tetragonal crystal structure with a (101) orientation.

[0031] The aforementioned second metal oxide has a tetragonal crystal structure and is oriented (101).

[0032] [4] According to the laminated structure described in [3], wherein the first buffer film is composed of the first metal oxide represented by the following composition formula (1),

[0033]

[0034] In formula (1), M is selected from one or more elements chosen from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements.

[0035] The above y1 satisfies 0 < y1 ≤ 0.3.

[0036] The above x1 satisfies 0 ≤ x1 ≤ 1 - y1.

[0037] The second buffer film described above is composed of the second metal oxide represented by the following formula (2).

[0038]

[0039] The above x2 satisfies 0≤x2<1 or x2=1.

[0040] [5] The laminated structure according to [3] has a piezoelectric film formed on the second buffer film described above.

[0041] The aforementioned piezoelectric film is composed of a metal nitride containing AlN.

[0042] The AlN contained in the above metal nitrides is oriented in (0001).

[0043] [6] The stacked structure according to any one of [2] to [5], wherein the substrate is made of a Si (100) substrate, or the SOI layer is made of a Si (100) film.

[0044] [7] The stacked structure according to any one of [2] to [5], wherein the substrate is made of a Si(111) substrate, or the SOI layer is made of a Si(111) film.

[0045] [8] According to the stacked structure described in [5], wherein the metal nitride comprises AlN with added Sc.

[0046] [9] A laminated structure having a substrate and a first buffer film formed on the substrate,

[0047] The aforementioned substrate is composed of a Si substrate or an SOI substrate. The SOI substrate comprises: a substrate composed of a Si substrate, an insulating layer on the substrate, and an SOI layer composed of a Si film on the insulating layer.

[0048] The aforementioned first buffer film is composed of a first metal oxide, which comprises: one or more metal elements selected from Group 4 elements, and one or more metal elements selected from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements.

[0049] When the first metal oxide is represented as a pseudocubic crystal, it is oriented in (100), or has a monoclinic crystal structure and is oriented in (111), or has a monoclinic crystal structure and is oriented in (11-1).

[0050]

[10] The laminated structure according to [9] has a second buffer film formed on the first buffer film,

[0051] The aforementioned second buffer film is composed of a second metal oxide, which contains one or more metal elements selected from Group 4 elements.

[0052] When the aforementioned second metal oxide is represented as a pseudocubic crystal, it exhibits a (100) orientation, or a monoclinic crystal structure with a (111) orientation, or a monoclinic crystal structure with a (11-1) orientation.

[0053]

[11] According to the stacked structure described in

[10] , the Si substrate is composed of a Si(100) substrate, or the SOI layer is composed of a Si(100) film.

[0054] The aforementioned first metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation, or a monoclinic crystal structure with a (11-1) orientation, or an orthorhombic crystal structure with a (100) orientation.

[0055] The aforementioned second metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation, or a monoclinic crystal structure with a (11-1) orientation, or an orthorhombic crystal structure with a (100) orientation.

[0056]

[12] According to the stacked structure described in

[10] , the Si substrate is composed of a Si(111) substrate, or the SOI layer is composed of a Si(111) film.

[0057] The aforementioned first metal oxide has a monoclinic crystal structure and is oriented (111), or has a monoclinic crystal structure and is oriented (11-1).

[0058] The aforementioned second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0059]

[13] According to the laminated structure described in

[11] or

[12] , wherein the first buffer film is composed of the first metal oxide represented by the following composition formula (3),

[0060]

[0061] In formula (3), M is selected from one or more elements chosen from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements.

[0062] The above y1 satisfies 0 < y1 ≤ 0.3.

[0063] The above x1 satisfies 0 ≤ x1 ≤ 1 - y1.

[0064] The second buffer film described above is composed of the second metal oxide represented by the following formula (4).

[0065]

[0066] The above x2 satisfies 0≤x2<1 or x2=1.

[0067]

[14] A stacked structure having a substrate, a buffer film formed on the substrate, and a semiconductor film formed on the buffer film.

[0068] The aforementioned substrate is composed of a Si substrate or an SOI substrate. The SOI substrate comprises: a substrate composed of a Si substrate, an insulating layer on the substrate, and an SOI layer composed of a Si film on the insulating layer.

[0069] The aforementioned buffer film is composed of a metal oxide comprising: one or more metal elements selected from Group 4 elements, and Si.

[0070] The aforementioned semiconductor film contains one or more elements selected from Si and Ge.

[0071] The aforementioned metal oxides, when represented as pseudocubic crystals, exhibit a (100) orientation.

[0072] The aforementioned semiconductor film exhibits a (100) orientation when represented as a pseudocubic crystal.

[0073]

[15] According to the stacked structure described in

[14] , the substrate is composed of a Si (100) substrate comprising a main surface composed of a Si (100) surface or the SOI substrate, wherein the SOI substrate comprises: the substrate, an insulating layer on the substrate, and an SOI layer composed of a Si (100) film on the insulating layer and comprising the main surface composed of a Si (100) surface.

[0074]

[16] According to the stacked structure described in

[15] , the metal oxide has a cubic crystal structure and is (100) oriented, or has a tetragonal crystal structure and is (001) oriented, or has a monoclinic crystal structure and is (100) oriented.

[0075]

[17] According to the laminated structure described in

[15] , the buffer film is composed of the metal oxide represented by the following composition formula (5).

[0076]

[0077] The above y1 satisfies 0 < y1 ≤ 0.3.

[0078] The above x1 satisfies 0≤x1≤1-y1.

[0079]

[18] According to the stacked structure described in

[15] , the semiconductor film has a cubic crystal structure and is (100) oriented.

[0080]

[19] According to the stacked structure described in

[15] , the semiconductor film is epitaxially grown.

[0081]

[20] According to the stacked structure described in

[15] , the semiconductor film is oriented such that the <100> direction of the main surface of the semiconductor film is along the <100> direction of the main surface of the Si contained in the substrate.

[0082]

[21] According to the stacked structure described in

[15] , the buffer film is oriented in such a way that when the pseudocubic crystal is represented, it is oriented along the <100> direction of the main surface of the metal oxide and along the <100> direction of the main surface of the Si contained in the substrate.

[0083]

[22] According to the stacked structure described in

[15] , the angle between the <100> direction along the main surface of the semiconductor film and the <100> direction along the main surface of the Si contained in the substrate is 1.2 to 1.76°.

[0084]

[23] An electronic device having a stacked structure according to any one of [1] to

[22] .

[0085] Invention Effects

[0086] The stacked structure of the present invention and the electronic device having the stacked structure can improve the crystallinity of the dielectric film, conductive film or semiconductor film formed on the Si substrate. Specifically, in the stacked structure of the present invention and the electronic device having the stacked structure, even if a dielectric film with a hexagonal crystal structure or a dielectric film or conductive film with a cubic, tetragonal or monoclinic crystal structure is formed on the buffer film, the dielectric film or conductive film with a hexagonal crystal structure can be easily oriented (0001) regardless of the plane orientation of the Si substrate, or the dielectric film or conductive film with a cubic, tetragonal or monoclinic crystal structure can be easily oriented (100) or (111) when represented as a pseudocubic crystal.

[0087] Alternatively, the stacked structure of the present invention and the electronic device having the stacked structure can improve the crystallinity of the Si film or SiGe film formed on the silicon substrate with a metal oxide film as a barrier in the stacked structure and the electronic device having the stacked structure. Attached Figure Description

[0088] Figure 1 This is a cross-sectional view illustrating an example of the stacked structure of Embodiment 1.

[0089] Figure 2 A cross-sectional view illustrating another example of the stacked structure of Embodiment 1.

[0090] Figure 3 A cross-sectional view illustrating another example of the stacked structure of Embodiment 1.

[0091] Figure 4 A cross-sectional view illustrating another example of the stacked structure of Embodiment 1.

[0092] Figure 5 This is a cross-sectional view showing an example of a layered structure of a variation of Embodiment 1.

[0093] Figure 6 A cross-sectional view showing other examples of the stacked structure of a modified embodiment 1.

[0094] Figure 7 This is a cross-sectional view of the electronic device according to Embodiment 2.

[0095] Figure 8 This is a cross-sectional view illustrating an example of the stacked structure of Embodiment 3.

[0096] Figure 9 A cross-sectional view illustrating another example of the stacked structure of Embodiment 3.

[0097] Figure 10 This is a cross-sectional view illustrating an example of the electronic device according to Embodiment 4.

[0098] Figure 11 A cross-sectional view illustrating another example of the electronic device of Embodiment 4.

[0099] Figure 12 A diagram illustrating the diffraction pattern of the stacked structure of Example 1.

[0100] Figure 13 A diagram illustrating the diffraction pattern of the stacked structure of Example 1.

[0101] Figure 14 A diagram illustrating the diffraction pattern of the stacked structure of Example 2.

[0102] Figure 15 A diagram illustrating the diffraction pattern of the stacked structure of Example 3.

[0103] Figure 16 A diagram illustrating the φ scan of the stacked structure of Example 3.

[0104] Figure 17 A diagram illustrating the diffraction pattern of the stacked structure of Example 4.

[0105] Figure 18 A diagram illustrating the diffraction pattern of the stacked structure of Example 5.

[0106] Figure 19 A diagram illustrating the diffraction pattern of the stacked structure of Example 6.

[0107] Figure 20 A diagram illustrating the diffraction pattern of the stacked structure of Example 7.

[0108] Figure 21 A diagram illustrating the diffraction pattern of the stacked structure of Example 8.

[0109] Figure 22 A diagram illustrating the diffraction pattern of the stacked structure of Example 8.

[0110] Figure 23 A diagram illustrating the diffraction pattern of the stacked structure of Example 9.

[0111] Figure 24A diagram illustrating the diffraction pattern of the stacked structure of Example 9.

[0112] Figure 25 A diagram illustrating the diffraction pattern of the stacked structure of Example 10.

[0113] Figure 26 A diagram illustrating the diffraction pattern of the stacked structure of Example 11.

[0114] Figure 27 A diagram illustrating the diffraction pattern of the stacked structure of Example 12.

[0115] Figure 28 A diagram illustrating the diffraction pattern of the stacked structure of Example 13.

[0116] Figure 29 A diagram illustrating the diffraction pattern of the stacked structure of Example 14.

[0117] Figure 30 A diagram illustrating the diffraction pattern of the stacked structure of Example 15.

[0118] Figure 31 A diagram illustrating the diffraction pattern of the stacked structure of Example 16.

[0119] Figure 32 A diagram illustrating the diffraction pattern of the stacked structure of Example 17.

[0120] Figure 33 A diagram illustrating the diffraction pattern of the stacked structure of Example 18.

[0121] Figure 34 A diagram illustrating the diffraction pattern of the stacked structure of Example 19.

[0122] Figure 35 A diagram illustrating the diffraction pattern of the stacked structure of Example 20.

[0123] Figure 36 A diagram illustrating the diffraction pattern of the stacked structure of Example 20.

[0124] Figure 37 A diagram illustrating the diffraction pattern of the stacked structure of Example 20.

[0125] Figure 38 A diagram illustrating the φ scan of the stacked structure of Example 20.

[0126] Figure 39 A diagram illustrating the diffraction pattern of the stacked structure of Example 21.

[0127] Figure 40A diagram illustrating the diffraction pattern of the stacked structure of Example 21.

[0128] Figure 41 A diagram illustrating the φ scan of the stacked structure of Example 21.

[0129] Figure 42 A diagram illustrating the diffraction pattern of the stacked structure of Example 22.

[0130] Figure 43 A diagram illustrating the diffraction pattern of the stacked structure of Example 22.

[0131] Figure 44 A diagram illustrating the diffraction pattern of the stacked structure of Example 22.

[0132] Figure 45 A diagram illustrating the φ scan of the stacked structure of Example 22. Detailed Implementation

[0133] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings.

[0134] Furthermore, the disclosed content is merely one example. Appropriate modifications that can be readily conceived by those skilled in the art while maintaining the spirit of the invention are naturally included within the scope of this invention. Additionally, for clarity, the accompanying drawings sometimes schematically represent the width, thickness, shape, etc., of various parts relative to the embodiments, but these are merely examples and not intended to limit the interpretation of the invention.

[0135] (Implementation Method 1)

[0136] <Layered Structure>

[0137] First, the stacked structure of Implementation Method 1 will be described. Figure 1 This is a cross-sectional view illustrating an example of the stacked structure of Embodiment 1. Figures 2 to 4 A cross-sectional view illustrating another example of the stacked structure of Embodiment 1.

[0138] Figure 1 and Figure 2 The stacked structure 10 shown has: a substrate 11 including a main surface 11p, a buffer film (first buffer film) 12 formed on the main surface 11p, i.e. on the substrate 11, and a buffer film (second buffer film) 13 formed on the buffer film 12.

[0139] exist Figure 1 In the example shown, substrate 11 is composed of a silicon (Si)(100) substrate containing a main surface 11p formed of Si(100) planes. Figure 2In the example shown, substrate 11 is made of SOI substrate, which includes: a substrate 11a made of Si substrate, an insulating layer 11b on substrate 11a, and an SOI (Silicon On Insulator) layer 11c made of Si (100) film on insulating layer 11b and including a main surface 11p made of Si (100) surface.

[0140] exist Figure 1 In the example shown, substrate 11 can be any Si substrate. Figure 2 In the example shown, the substrate 11 can be any SOI substrate comprising a substrate 11a made of a Si substrate, an insulating layer 11b on the substrate 11a, and an SOI layer 11c made of a Si film on the insulating layer 11b. However, when the substrate 11 is made of a Si (100) substrate, the manufacturing cost of the stacked structure can be reduced compared to when the substrate 11 is not made of a Si (100) substrate. Furthermore, when the SOI layer 11c is made of a Si (100) film, the manufacturing cost of the stacked structure can be reduced compared to when the SOI layer 11c is not made of a Si (100) film.

[0141] Or, in Figure 1 In the example shown, substrate 11 can also be made of a Si(111) substrate containing a main surface 11p formed by Si(111) planes. When substrate 11 is made of a Si(111) substrate, compared to the case where substrate 11 is not made of a Si(111) substrate, the Si(111) plane has three-dimensional symmetry, for example, the Y2O3(111) plane with three-dimensional symmetry is easy to epitaxially grow on the Si(111) plane, making it easier for Y2O3 to be (111) oriented. Similarly, SOI layer 11c can also be made of a Si(111) film. When SOI layer 11c is made of a Si(111) film, compared to the case where SOI layer 11c is not made of a Si(111) film, the Si(111) plane has three-dimensional symmetry, for example, the Y2O3(111) plane with three-dimensional symmetry is easy to epitaxially grow on the Si(111) plane, making it easier for Y2O3 to be (111) oriented.

[0142] Buffer film 12 is composed of a first metal oxide, which comprises one or more metal elements selected from Group 4 elements, and one or more metal elements selected from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. Buffer film 13 is composed of a second metal oxide, which comprises one or more metal elements selected from Group 4 elements. The first metal oxide is (111) oriented when represented as a pseudocubic crystal, and the second metal oxide is (111) oriented when represented as a pseudocubic crystal.

[0143] In this specification, the term "metal oxide with (111) orientation when represented as pseudocubic" means that the metal oxide has a cubic crystal structure and is (111) oriented at room temperature, or even if it has a tetragonal or monoclinic crystal structure at room temperature, it undergoes a phase transition at high temperature and has a cubic crystal structure with (111) orientation (the same applies to the case where it is (100) oriented when represented as pseudocubic).

[0144] In the technology described in the aforementioned Patent Document 1, the crystalline film formed on a Si substrate having a (100) crystalline surface includes a Zr film and a stacked film or YSZ film on which a ZrO2 film and a Y2O3 film are stacked. However, it is not possible to align the ZrO2 film (111) on a Si substrate having a (100) crystalline surface, so it is difficult to align the piezoelectric film, such as a dielectric film, made of AlN on the ZrO2 film (0001).

[0145] In the technology described in Patent Document 2 above, the film structure comprises: a Si(111) substrate, a buffer film containing ZrO2 formed on the Si(111) substrate and oriented in a (111) manner, a Pt layer formed on the buffer film and oriented in a (111) manner, and a piezoelectric film composed of AlN formed on the Pt layer and oriented in a (0001) manner. Here, AlN has a hexagonal crystal structure. However, when forming an AlN film oriented in a (0001) manner on a Si substrate having a different plane orientation than the Si(111) substrate, such as a Si(100) substrate, it is difficult to form a piezoelectric film, i.e., a dielectric film, etc., composed of an AlN film having the same quality as the AlN film formed on the Si(111) substrate with a ZrO2 film in between.

[0146] Furthermore, although YSZ is a material in which Y2O3 is added as a stabilizer to ZrO2, in the technology described in Patent Document 1 above, when a dielectric film or conductive film with a cubic, tetragonal, or monoclinic crystal structure is oriented as a pseudocubic crystal on a Si substrate having a (100) or (111) crystal plane, and with a laminated film or YSZ film in between, a material that is more stable and easier to control the orientation of the dielectric film than conventional YSZ is preferred. However, it is difficult to use a material that is more stable and easier to control the orientation of the dielectric film or conductive film than conventional YSZ.

[0147] On the other hand, the stacked structure of this embodiment 1 has a buffer film 12 and a buffer film 13 sequentially formed on a Si substrate or an SOI substrate. The buffer film 12 is composed of a first metal oxide, which includes one or more metal elements selected from Group 4 elements and one or more metal elements selected from Nb, Ta, Si, Ti, rare earth elements, Al and Group 2 elements. The buffer film 13 is composed of a second metal oxide, which includes one or more metal elements selected from Group 4 elements. The first metal oxide is (111) oriented when represented as a pseudocubic crystal, and the second metal oxide is (111) oriented when represented as a pseudocubic crystal.

[0148] In this case, regardless of the orientation of the Si substrate, since the buffer film 12 and the buffer film 13 can each be oriented (111), the piezoelectric film formed on the buffer film 13 can be oriented (0001). Therefore, in a laminated structure having a buffer film formed on a Si substrate and an electronic device having the laminated structure, even if a piezoelectric film made of AlN is formed on the buffer film, the piezoelectric film made of AlN with a certain quality can be oriented (0001) regardless of the orientation of the Si substrate, thereby unifying the polarization direction of the piezoelectric film to a direction perpendicular to the main surface 11p. Furthermore, even if a dielectric film or conductive film with a hexagonal crystal structure or a cubic, tetragonal or monoclinic crystal structure is formed on the buffer film, it is easy to perform (0001) orientation on the dielectric film or conductive film with a hexagonal crystal structure, or to perform (100) orientation or (111) orientation on the dielectric film or conductive film with a cubic, tetragonal or monoclinic crystal structure when represented as a pseudocubic crystal.

[0149] According to Embodiment 1, a piezoelectric film 14 can be easily grown on a substrate 11 made of a Si substrate or an SOI substrate in a single orientation state, with a buffer film 12 made of a first metal oxide and a buffer film 13 made of a second metal oxide as a barrier. This can be attributed to a so-called crystal growth mechanism, which, for example, is driven by the dynamic lattice matching effect resulting from the twinned martensitic phase transformation exhibited by the first and second metal oxides, acting as the driving force, motive force, and propulsion force for the growth of the piezoelectric film 14 in a single orientation state. However, it is not necessarily limited to this theory.

[0150] Preferred examples of the first metal oxide are shown in Table 1. Table 1 shows the preferred examples of the first metal oxide and the standard Gibbs free energy of formation (kJ / mol) for each first metal oxide. -1 The value of ) is the value recorded in Non-Patent Document 1.

[0151] [Table 1]

[0152]

[0153] Including HfO2 and ZrO2, the standard Gibbs free energy of formation values ​​of each of the first metal oxides shown in Table 1 are lower than the standard Gibbs free energy of formation value of SiO2. In this case, the metal elements contained in each first metal oxide reduce the SiO2 on the Si substrate and oxidize themselves, thereby enabling each first metal oxide to grow directly on the Si substrate.

[0154] The laminated structure 10 of this embodiment 1 may also not have a buffer film 13. In this case, by making the first metal oxide contained in the buffer film 12 oriented in (111) when represented as a pseudocubic crystal, the piezoelectric film formed on the buffer film 12 is oriented in (0001).

[0155] However, when the laminated structure 10 has a buffer film 13, the types of metal elements contained in the first metal oxide contained in the buffer film 12 and the second metal oxide contained in the buffer film 13 can be different. Therefore, for example, the buffer film 12 can use a first metal oxide that is not prone to martensitic phase transformation but has high self-orientation, and the buffer film 13 can use a second metal oxide that has low self-orientation but is prone to martensitic phase transformation. The buffer film as a whole composed of the buffer film 12 and the buffer film 13 can form an orientation-controlled piezoelectric film 14 on the substrate 11 with high yield.

[0156] Furthermore, in the stacked structure 10 of this embodiment 1, similar to the stacked structure of embodiment 6 described later, the substrate 11 can be made of a Si (100) substrate or the SOI layer 11c can be made of a Si (100) film, and the first metal oxide contained in the buffer film 12 can contain Si. In this case, similar to the stacked structure of embodiment 6 described later, by making the first metal oxide contained in the buffer film 12 (100) oriented when represented as a pseudocubic crystal, similar to the stacked structure 10 of embodiment 3 described later, the semiconductor film formed on the buffer film 12 made of Si or SiGe can be (100) oriented.

[0157] Furthermore, the stacked structure 10 of this embodiment 1 may also omit the buffer film 13, the substrate 11 may be made of a Si (100) substrate or the SOI layer 11c may be made of a Si (100) film, and the first metal oxide contained in the buffer film 12 may contain Si. In this case, similar to the stacked structure 10 of embodiment 3 described later, by making the first metal oxide contained in the buffer film 12 (100) oriented when represented as a pseudocubic crystal, the semiconductor film formed on the buffer film 12, which is made of Si or SiGe, can be (100) oriented.

[0158] Preferably, the first metal oxide has a cubic crystal structure with a (111) orientation, or a tetragonal crystal structure with a (101) orientation. In the case where the first metal oxide has a tetragonal crystal structure, the lattice constant of the a-axis is approximately 1 / (2π) compared to the lattice constant of the c-axis. 1 / 2 ) times. In this case, the first metal oxide, which has a tetragonal crystal structure and is (101) oriented, is (111) oriented when represented as a pseudocubic crystal.

[0159] Similarly, preferably, the second metal oxide has a tetragonal crystal structure and is oriented (101). When the second metal oxide has a tetragonal crystal structure, the lattice constant of the a-axis is approximately 1 / (2π) compared to the lattice constant of the c-axis. 1 / 2 ) times. In this case, the second metal oxide, which has a tetragonal crystal structure and is (101) oriented, is (111) oriented when represented as a pseudocubic crystal.

[0160] Preferably, the buffer membrane 12 is composed of a first metal oxide represented by the following composition formula (1).

[0161]

[0162] In the composition formula (1), M is selected from one or more of Nb, Ta, Si, Ti, rare earth elements, Al and group II elements.

[0163] In the above composition (1), y1 satisfies 0<y1≤0.3, and x1 satisfies 0≤x1≤1-y1.

[0164] In the first metal oxide represented by the above composition formula (1), the case where M is yttrium (Y) and satisfies 0 < x1 < 1 and 0 < y ≤ 0.3 is sometimes referred to as YHZO.

[0165] Furthermore, preferably, the buffer membrane 13 is composed of a second metal oxide represented by the following composition formula (2).

[0166]

[0167] In the above composition (2), x2 satisfies 0≤x2<1 or satisfies x2=1.

[0168] In the second metal oxide represented by the above composition formula (2), the case that satisfies 0 < x2 < 1 is sometimes referred to as HZO.

[0169] In this case (but satisfying 0 < x1 ≤ 1 - y1 and 0 < x2 < 1), both the first metal oxide and the second metal oxide are formed by replacing at least part or all of the Hf in HfO2 with Zr. Since Zr is a Group 4 element and a Period 5 element, and Hf is a Group 4 element and a Period 6 element, their chemical properties are similar. Therefore, it is possible to prevent or suppress changes in their crystal structure caused by temperature conditions during the formation of the film buffer film 12.

[0170] Preferably, the buffer film 13 is composed of a second metal oxide containing Hf and one or more metal elements selected from Group 4 elements other than Hf, where x2 satisfies 0 ≤ x2 < 1. This enhances the dynamic lattice matching effect brought about by the twinned martensitic phase transformation.

[0171] Figure 3 and Figure 4 The illustrated laminated structure 10 has a piezoelectric film 14 formed on a buffer film 13. The piezoelectric film 14 is composed of a metal nitride containing aluminum nitride (AlN), wherein the AlN contained in the metal nitride is oriented in a (0001) pattern. In the case where the laminated structure 10 does not have a buffer film 13, the laminated structure 10 has a piezoelectric film 14 formed directly on a buffer film 12.

[0172] As mentioned above, in the stacked structure 10 of this embodiment 1, regardless of the orientation of the Si substrate, since the buffer film 12 and the buffer film 13 can each be (111) oriented, the piezoelectric film 14 formed on the buffer film 13 by AlN can be (0001) oriented, and the polarization direction of the piezoelectric film 14 is unified to the direction perpendicular to the main surface 11p.

[0173] Preferably, the metal nitride comprises AlN with added Sc. When Sc is added to the AlN contained in the metal nitride, the piezoelectricity of the piezoelectric film 14 can be improved compared to when Sc is not added to the AlN contained in the metal nitride.

[0174] It should be noted that, as the piezoelectric film 14, materials composed of metal nitrides containing gallium nitride (GaN) or metal oxides containing lithium niobate (LiNbO3) or lithium tantalate (LiTaO3) can also be used to replace AlN. Furthermore, it is preferable that GaN, LiNbO3, and LiTaO3 are oriented in a (0001) pattern.

[0175] <Examples of variations of layered structures>

[0176] Next, a modified example of the stacked structure of Embodiment 1 will be described. The stacked structure of this modified example differs from the stacked structure of Embodiment 1 in that the first metal oxide is oriented (100) when represented as a pseudocubic crystal, or has a monoclinic crystal structure and is oriented (111), or has a monoclinic crystal structure and is oriented (11-1). Figure 5 This is a cross-sectional view showing an example of a layered structure of a variation of Embodiment 1. Figure 6 A cross-sectional view showing other examples of the stacked structure of a modified embodiment 1.

[0177] Figure 5 and Figure 6 The layered structure 10a shown is also similar to Figure 1 and Figure 2 The stacked structure 10 shown is the same, having: a substrate 11 including a main surface 11p, a buffer film (first buffer film) 12 formed on the main surface 11p, i.e. on the substrate 11, and a buffer film (second buffer film) 13 formed on the buffer film 12.

[0178] exist Figure 5 In the example shown, with Figure 1 The example shown is similar; substrate 11 is composed of a silicon (Si)(100) substrate containing a main surface 11p formed of Si(100) planes. Figure 6 In the example shown, with Figure 2 As shown in the example, substrate 11 is composed of an SOI substrate, which includes: a substrate 11a composed of a Si substrate, an insulating layer 11b on the substrate 11a, and an SOI layer 11c composed of a Si (100) film on the insulating layer 11b and including a main surface 11p composed of the Si (100) surface.

[0179] exist Figure 5 In the example shown, substrate 11 can be any Si substrate. Figure 6 In the example shown, the substrate 11 can be any SOI substrate comprising a substrate 11a made of a Si substrate, an insulating layer 11b on the substrate 11a, and an SOI layer 11c made of a Si film on the insulating layer 11b. However, when the substrate 11 is made of a Si (100) substrate, the manufacturing cost of the stacked structure can be reduced compared to when the substrate 11 is not made of a Si (100) substrate. Furthermore, when the SOI layer 11c is made of a Si (100) film, the manufacturing cost of the stacked structure can be reduced compared to when the SOI layer 11c is not made of a Si (100) film.

[0180] Or, in Figure 5 In the example shown, substrate 11 can also be made of a Si(111) substrate containing a main surface 11p formed by Si(111) planes. When substrate 11 is made of a Si(111) substrate, compared to the case where substrate 11 is not made of a Si(111) substrate, the Si(111) plane has three-dimensional symmetry, for example, the Y2O3(111) plane with three-dimensional symmetry is easy to epitaxially grow on the Si(111) plane, making it easier for Y2O3 to be (111) oriented. Similarly, SOI layer 11c can also be made of a Si(111) film. When SOI layer 11c is made of a Si(111) film, compared to the case where SOI layer 11c is not made of a Si(111) film, the Si(111) plane has three-dimensional symmetry, for example, the Y2O3(111) plane with three-dimensional symmetry is easy to epitaxially grow on the Si(111) plane, making it easier for Y2O3 to be (111) oriented.

[0181] The buffer film 12 is composed of a first metal oxide, which comprises: one or more metal elements selected from Group 4 elements, and one or more metal elements selected from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. When the first metal oxide is represented as a pseudocubic crystal, it is oriented at (100), or has a monoclinic crystal structure and is oriented at (111), or has a monoclinic crystal structure and is oriented at (11-1). When the second metal oxide is represented as a pseudocubic crystal, it is oriented at (100), or has a monoclinic crystal structure and is oriented at (111), or has a monoclinic crystal structure and is oriented at (11-1).

[0182] For example, when the substrate 11 is made of a Si (100) substrate or the SOI layer 11c is made of a Si (100) film, by making the first metal oxide (represented as a pseudo-cubic crystal) oriented (100) and the second metal oxide (represented as a pseudo-cubic crystal) oriented (100), the buffer film 12 and the buffer film 13 can each be oriented (100) in a pseudo-cubic crystal form. This makes it easy to oriented the dielectric film or conductive film formed on the buffer film 13, which has a cubic, tetragonal, or monoclinic crystal structure, in a pseudo-cubic crystal form (100).

[0183] On the other hand, for example, when the substrate 11 is made of a Si (111) substrate or the SOI layer 11c is made of a Si (111) film, by making the first metal oxide have a monoclinic crystal structure and a (111) orientation or a monoclinic crystal structure and a (11-1) orientation, and making the second metal oxide have a monoclinic crystal structure and a (111) orientation or a monoclinic crystal structure and a (11-1) orientation, it is possible to make the buffer film 12 and the buffer film 13 each have a pseudocubic crystal representation and a (111) orientation, thereby making it easy to make the dielectric film or conductive film formed on the buffer film 13 with a cubic, tetragonal or monoclinic crystal structure have a (111) orientation when represented by a pseudocubic crystal.

[0184] Therefore, in a stacked structure having a buffer film formed on a Si substrate and an electronic device having the stacked structure, even if a dielectric film or conductive film with a hexagonal crystal structure or a cubic, tetragonal or monoclinic crystal structure is formed on the buffer film, the dielectric film or conductive film with a hexagonal crystal structure can be easily oriented (0001) regardless of the plane orientation of the Si substrate, or the dielectric film or conductive film with a cubic, tetragonal or monoclinic crystal structure can be easily oriented (100) or (111) when represented as a pseudocubic crystal.

[0185] In other words, when the Si substrate is composed of a Si (100) substrate or the SOI layer is composed of a Si (100) film, the first metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation, or a monoclinic crystal structure with a (11-1) orientation, or an orthorhombic crystal structure with a (100) orientation. Furthermore, the second metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation, or a monoclinic crystal structure with a (11-1) orientation, or an orthorhombic crystal structure with a (100) orientation.

[0186] Furthermore, when the Si substrate is composed of a Si(111) substrate or the aforementioned SOI layer is composed of a Si(111) film, the first metal oxide has a monoclinic crystal structure and is oriented in (111), or has a monoclinic crystal structure and is oriented in (11-1). Furthermore, the second metal oxide has a monoclinic crystal structure and is oriented in (111), or has a monoclinic crystal structure and is oriented in (11-1).

[0187] The laminated structure 10a of this modified example may also be without the buffer film 13. In this case, by aligning the first metal oxide contained in the buffer film 12 in a pseudocubic crystal (111) orientation, the piezoelectric film formed on the buffer film 12 made of AlN can also be oriented in a (0001) orientation. Furthermore, even if a dielectric film or conductive film with a hexagonal crystal structure or a dielectric film or conductive film with a cubic, tetragonal, or monoclinic crystal structure is formed on the buffer film, it is easy to align the dielectric film or conductive film with a hexagonal crystal structure in a (0001) orientation, or to easily align the dielectric film or conductive film with a cubic, tetragonal, or monoclinic crystal structure in a pseudocubic crystal (100) or (111) orientation.

[0188] In this modified example, as in embodiment 1, preferably, the buffer film 12 is composed of a first metal oxide represented by the following composition formula (3).

[0189]

[0190] In the composition formula (3), M is selected from one or more of Nb, Ta, Si, Ti, rare earth elements, Al and group II elements.

[0191] In the above composition (3), y1 satisfies 0<y1≤0.3, and x1 satisfies 0≤x1≤1-y1. The above composition (3) is the same composition as the above composition (1).

[0192] Furthermore, in this modified example, as in Embodiment 1, preferably, the buffer film 13 is composed of a second metal oxide represented by the following composition formula (4).

[0193]

[0194] In the above composition (4), x2 satisfies 0≤x2<1 or satisfies x2=1. The above composition (4) is the same composition as the above composition (2).

[0195] In this case (but satisfying 0 < x1 ≤ 1 - y1 and 0 < x2 < 1), both the first metal oxide and the second metal oxide are formed by replacing at least part or all of the Hf in HfO2 with Zr. Since Zr is a Group 4 element and a Period 5 element, and Hf is a Group 4 element and a Period 6 element, their chemical properties are similar. Therefore, it is possible to prevent or suppress changes in their crystal structure caused by temperature conditions during the formation of the film buffer film 12.

[0196] In this modified example, similar to Embodiment 1, the buffer film 13 is preferably composed of a second metal oxide containing Hf and one or more metal elements selected from Group 4 elements other than Hf, where x2 satisfies 0 ≤ x2 < 1. This enhances the dynamic lattice matching effect brought about by the twinned martensitic phase transformation.

[0197] (Implementation Method 2)

[0198] Next, the electronic device of Embodiment 2 will be described. The electronic device of Embodiment 2 is an electronic device composed of an FBAR (Film Bulk Acoustic Resonator) having a laminated structure of Embodiment 1 or a modified example of a laminated structure of Embodiment 1.

[0199] Figure 7 This is a cross-sectional view of the electronic device according to Embodiment 2. Figure 7 The electronic device 20 shown includes: a substrate 11, a buffer film 12, a buffer film 13, a conductive film 15 formed on the buffer film 13 and made of, for example, platinum (Pt), a piezoelectric film 14 formed on the conductive film 15, and a conductive film 16 formed on the piezoelectric film 14 and made of, for example, Pt.

[0200] In addition, such as Figure 7 As shown, when the stacked structure 10 has a substrate 11 serving as an SOI substrate, for example, by photolithography and etching using an alkaline etching solution, such as... Figure 7 As shown, an opening 11d can be formed by etching a portion of the substrate 11a in the substrate 11. Furthermore, a pattern can be formed by etching a portion of the conductive film 16, which serves as the upper electrode, for example, using photolithography and etching techniques.

[0201] Therefore, as Figure 7 As shown, an electronic device can be formed from an FBAR, which is composed of a stacked structure 10 having an insulating layer 11b, an SOI layer 11c, a buffer film 12, a buffer film 13, a conductive film 15, a piezoelectric film 14, and a conductive film 16 within an opening 11d in a substrate 11a.

[0202] In the electronic device of this embodiment 2, by aligning the AlN contained in the piezoelectric film 14 with a (0001) orientation, compared with the case where AlN is not aligned with a (0001) orientation, the polarization direction of AlN can be made parallel to the electric field applied to the piezoelectric film 14, thereby increasing the piezoelectric constant of the piezoelectric film 14.

[0203] Alternatively, a piezoelectric actuator can be easily formed from a microelectromechanical system (MEMS) consisting of multiple piezoelectric elements formed on the substrate 11a with excellent shape accuracy.

[0204] (Implementation Method 3)

[0205] Next, the laminated structure of Embodiment 3 will be described. The laminated structure of Embodiment 3 differs from the laminated structure of Embodiment 1 in that the ZrO2 or HfO2 contained in HZO is stabilized by SiO2, it has a buffer film 12 but not a buffer film 13, and a semiconductor film 31 is formed on the buffer film 12 instead of the piezoelectric film 14. Figure 8 This is a cross-sectional view illustrating an example of the stacked structure of Embodiment 3. Figure 9 A cross-sectional view illustrating another example of the stacked structure of Embodiment 3.

[0206] Figure 8 The stacked structure 10a shown has: a substrate 11 including a main surface 11p, a buffer film (first buffer film) 12 formed on the main surface 11p, i.e. on the substrate 11, and a semiconductor film 31 formed on the buffer film 12.

[0207] exist Figure 8 In the example shown, substrate 11 is composed of a Si(100) substrate containing a main surface 11p formed of Si(100) planes. Figure 9 In the example shown, the substrate 11 is made of an SOI substrate, which includes: a substrate 11a made of a Si substrate, an insulating layer 11b on the substrate 11a, and an SOI layer 11c made of a Si (100) film on the insulating layer 11b and including a main surface 11p formed by the Si (100) surface.

[0208] exist Figure 8 In the example shown, substrate 11 can be any Si substrate. Figure 9 In the example shown, the substrate 11 can be any SOI substrate comprising a substrate 11a made of a Si substrate, an insulating layer 11b on the substrate 11a, and an SOI layer 11c made of a Si film on the insulating layer 11b. However, when the substrate 11 is made of a Si (100) substrate, the manufacturing cost of the stacked structure can be reduced compared to when the substrate 11 is not made of a Si (100) substrate. Furthermore, when the SOI layer 11c is made of a Si (100) film, the manufacturing cost of the stacked structure can be reduced compared to when the SOI layer 11c is not made of a Si (100) film.

[0209] The buffer film 12 is composed of a metal oxide containing one or more metal elements selected from Group 4 elements and Si. The semiconductor film 31 contains one or more elements selected from Si and Ge. The metal oxide is oriented (100) when represented as a pseudocubic crystal, and the semiconductor film 31 is oriented (100) when represented as a pseudocubic crystal.

[0210] In this specification, the term "metal oxide with (100) orientation when represented as pseudocubic" means that the metal oxide has a cubic crystal structure and is (100) oriented at room temperature, or even if it has a tetragonal or monoclinic crystal structure at room temperature, it is (100) oriented when it undergoes a phase transition at high temperature and has a cubic crystal structure.

[0211] In the technology described in Patent Document 3 above, after depositing La2O3, a metal oxide, onto a Si substrate with a (001) plane orientation and transforming it into a crystalline substance of La2O3 single crystal, the Si, which serves as the channel layer, is epitaxially grown, or a SiGe layer is formed on the Si substrate, or a SiGe layer is stacked with an oxide film in between. However, the crystallinity of the Si film or SiGe film formed on the silicon substrate with an oxide film in between is insufficient.

[0212] Furthermore, in the technology described in Patent Document 4 above, the semiconductor device includes: a gate insulating film formed on a silicon substrate and composed of an HfO2 film or a ZrO2 film, and a gate electrode formed on the gate insulating film and composed of a Si film or a SiGe film. Moreover, when the gate electrode is composed of a polycrystalline Si film or a polycrystalline SiGe film, compared to when the gate electrode is composed of an amorphous Si film or an amorphous SiGe film, conductive impurities (e.g., boron) implanted into the gate electrode in subsequent processes can be efficiently thermally diffused along the grain boundaries, reducing the thermal history of subsequent processes and improving the leakage current characteristics or long-term reliability of the gate insulating film. However, the Si film or SiGe film formed on the silicon substrate through an oxide film has insufficient crystallinity.

[0213] On the other hand, the stacked structure of this embodiment 3 has a buffer film 12 and a semiconductor film 31 sequentially formed on a Si substrate or an SOI substrate. The buffer film 12 is composed of a metal oxide containing one or more metal elements selected from Group 4 elements and Si. The metal oxide is (100) oriented when represented as a pseudocubic crystal, and the semiconductor film 31 is (100) oriented when represented as a pseudocubic crystal.

[0214] In this case, in a field-effect transistor using a semiconductor film 31 as the channel layer, the crystallinity of the Si film or SiGe film formed on the silicon substrate with an oxide film in between can be improved. Therefore, Si epitaxially grows on the Si substrate with a buffer film 12 made of metal oxide in between as the channel layer, and SiGe layer can be formed on the Si substrate with a buffer film 12 made of metal oxide in between.

[0215] Furthermore, in a stacked structure having a semiconductor film formed on a Si substrate with a gate insulating film in between, and in an electronic device having the stacked structure, compared to the case where the gate electrode is made of a polycrystalline Si film or a polycrystalline SiGe film, conductive impurities (e.g., boron) injected into the gate electrode in subsequent processes can be thermally diffused more efficiently along the grain boundaries, which can further reduce the thermal history of subsequent processes and further improve the leakage current characteristics or long-term reliability and other electrical characteristics of the gate insulating film.

[0216] According to Embodiment 3, a semiconductor film 31 can be easily grown on a substrate 11 made of a Si substrate in a single orientation state, with the buffer film 12 made of metal oxide as a barrier. This can be attributed to a so-called crystal growth mechanism, which, for example, is driven by the dynamic lattice matching effect of the twinned martensitic phase transformation exhibited by the metal oxide, acting as the driving force, motive force, and propulsion force for the growth of the semiconductor film 31 in a single orientation state. However, it is not necessarily limited to this theory.

[0217] As illustrated in Table 1 above, the standard Gibbs free energy of formation for metal oxides including HfO2 and ZrO2 is lower than that for SiO2. In this case, the metal element contained in the metal oxide reduces the SiO2 on the Si substrate and oxidizes itself, thereby allowing the metal oxide to be grown directly on the Si substrate.

[0218] Preferably, the metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation. In this case, a Si film or SiGe film with a cubic crystal structure and a (100) orientation can be epitaxially grown on the buffer film 12.

[0219] Preferably, the buffer membrane 12 is composed of a metal oxide represented by the following composition formula (5).

[0220]

[0221] In the above composition formula (5), y1 satisfies 0 < y1 ≤ 0.3, and x1 satisfies 0 ≤ x1 ≤ 1 - y1. Hereinafter, in the metal oxides represented by the above composition formula (5), the case that satisfies 0 < x1 < 1 is sometimes referred to as SHZO.

[0222] In this case (but satisfying 0 < x1 ≤ 1 - y1 and 0 < y1 ≤ 0.3), the metal oxide is formed by replacing at least part or all of the Hf in HfO2 with Zr. Since Zr is a Group 4 element and a Period 5 element, and Hf is a Group 4 element and a Period 6 element, and their chemical properties are similar, it is possible to prevent or suppress changes in their crystal structure caused by temperature conditions during the formation of the film buffer film 12.

[0223] Preferably, the semiconductor film 31 has a cubic crystal structure and is (100) oriented. In this case, for example, with an HfO2 film or a ZrO2 film in between, a single-crystal Si film or a single-crystal SiGe film can be easily formed on the silicon substrate, which can easily improve the leakage current characteristics or long-term reliability and other electrical characteristics of the gate insulating film.

[0224] Preferably, the semiconductor film 31 is epitaxially grown. In this case, compared with the case where the semiconductor film is not epitaxially grown, the semiconductor film 31 is more likely to have a cubic crystal structure and be (100) oriented, and can easily form a single crystal Si film or a single crystal SiGe film.

[0225] Preferably, the semiconductor film 31 is oriented such that the <100> direction along the main surface 11p of the semiconductor film 31 is aligned with the <100> direction along the main surface 11p of the Si contained in the substrate 11. In this case, compared to the case where the <100> direction along the main surface 11p of the semiconductor film 31 is not aligned with the <100> direction along the main surface 11p of the Si contained in the substrate 11, the semiconductor film 31 is more likely to have a cubic crystal structure and be (100) oriented, and can be easily formed into a single-crystal Si film or a single-crystal SiGe film. In this specification, the term "first direction along second direction" means that the angle between the first direction and the second direction is 10° or less.

[0226] Preferably, the buffer film 12 is oriented such that, in a pseudo-cubic crystal representation, the direction of the metal oxide principal plane 11p is aligned with the direction of the Si principal plane 11p contained in the substrate 11 along the <100> direction. In this case, compared to the case where, in a pseudo-cubic crystal representation, the direction of the metal oxide principal plane 11p is not aligned with the direction of the Si principal plane 11p contained in the substrate 11, the semiconductor film 31 is more likely to have a cubic crystal structure and be (100) oriented, and can be easily formed into a single-crystal Si film or a single-crystal SiGe film.

[0227] Preferably, the angle between the <100> direction along the main surface of the semiconductor film 31 and the <100> direction along the main surface 11p of the Si contained in the substrate 11 is 1.2 to 1.76°. When the angle between the <100> direction along the main surface of the semiconductor film 31 and the <100> direction along the main surface 11p of the Si contained in the substrate 11 is 1.2° or more, compared with the case where the angle is less than 1.2°, the angle between the grain boundary of the semiconductor film 31 and the grain boundary of the buffer film 12 is also larger, so conductive impurities implanted into the gate electrode in subsequent processes are less likely to enter the buffer film 12. Furthermore, when the angle between the <100> direction along the main surface of the semiconductor film 31 and the <100> direction along the main surface 11p of the Si contained in the substrate 11 is 1.76° or less, compared with the case where the angle is more than 1.76°, a single-crystal Si film or a single-crystal SiGe film can be formed more easily.

[0228] (Implementation Method 4)

[0229] Next, the electronic device of Embodiment 4 will be described. This electronic device of Embodiment 4 is an electronic device composed of MOSFETs having the stacked structure of Embodiment 3.

[0230] Figure 10 This is a cross-sectional view illustrating an example of the electronic device of Embodiment 4. Figure 11 A cross-sectional view illustrating another example of the electronic device of Embodiment 4.

[0231] exist Figure 10 In the example shown, the electronic device 20a has a stacked structure 10a, which includes a substrate 11, a buffer film 12, and a semiconductor film 31 formed on the buffer film 12. The buffer film 12, serving as an insulating layer, is formed on the substrate 11, which is a silicon substrate. The semiconductor film 31 is formed on the buffer film 12. The semiconductor film 31 includes a channel layer 31a, and a source region 31b and a drain region 31c, which have different conductivity types than the channel layer 31a. A gate insulating film 32, made of an oxide such as SiO2, is formed on the channel layer 31a. A gate electrode 33, made of polysilicon or metal, is formed on the gate insulating film 32. The stacked structure 10a, having a substrate 11, a buffer film 12, and a semiconductor film 31, has a device region 34 on which a MOSFET is formed and an isolation region 35 separating the device region 34. A device isolation insulating film 36 is formed on the isolation region 35.

[0232] exist Figure 10The electronic device 20a shown is similar to the stacked structure 10a of Embodiment 3, having a buffer film 12 and a semiconductor film 31 sequentially formed on a Si substrate or an SOI substrate. The buffer film 12 is composed of a metal oxide containing one or more metal elements selected from Group 4 elements and Si. The semiconductor film 31 contains one or more elements selected from Si and Ge. The metal oxide is (100) oriented when represented as a pseudocubic crystal, and the semiconductor film 31 is (100) oriented when represented as a pseudocubic crystal.

[0233] In this case, in a MOSFET using semiconductor film 31 as the channel layer, the crystallinity of the Si film or SiGe film formed on the silicon substrate through the oxide film can be improved. Therefore, by epitaxially growing the Si film, which serves as the channel layer, on the Si substrate through the metal oxide buffer film 12, or by forming the SiGe film on the Si substrate through the metal oxide buffer film 12, the crystallinity of the Si film or SiGe film can be improved, thereby achieving, for example, a MOSFET with excellent mobility.

[0234] On the other hand, Figure 11 In the example shown, electronic device 20b has a stacked structure 10a, which includes a substrate 11, a buffer film 12, and a semiconductor film 31 formed on the buffer film 12. On the silicon substrate 11, there is a device region 42 for forming semiconductor elements such as transistors and an isolation region 43 that isolates the device region 42. An element isolation insulating film 44 is formed in the isolation region 43. Furthermore, although not shown in the figure, a well region is formed within the substrate 11 of the device region 42.

[0235] A gate insulating film 12a, consisting of a buffer film 12, is formed on the substrate 11 of the element region 42. A gate electrode 31d, consisting of a semiconductor film 31, is formed on the gate insulating film 12a. A source region 45 and a drain region 46 are formed on the upper layer of the substrate 11, separated by a channel region (not shown) below the gate electrode 31d.

[0236] exist Figure 11 The electronic device 20b shown is similar to the stacked structure 10a of Embodiment 3, having a buffer film 12 and a semiconductor film 31 sequentially formed on a Si substrate or an SOI substrate. The buffer film 12 is composed of a metal oxide containing one or more metal elements selected from Group 4 elements and Si. The semiconductor film 31 contains one or more elements selected from Si and Ge. The metal oxide is (100) oriented when represented as a pseudocubic crystal, and the semiconductor film 31 is (100) oriented when represented as a pseudocubic crystal.

[0237] In this case, a single-crystal Si film or a single-crystal SiGe film can be formed on a silicon substrate through, for example, an HfO2 film or a ZrO2 film. Therefore, compared with the case where the gate electrode is composed of a polycrystalline Si film or a polycrystalline SiGe film, conductive impurities (e.g., boron) implanted into the gate electrode in subsequent processes can be thermally diffused more efficiently along the grain boundaries, which can further reduce the thermal history of subsequent processes and further improve the leakage current characteristics or long-term reliability and other electrical characteristics of the gate insulating film.

[0238] Example

[0239] The present invention will now be described in more detail based on the embodiments, but the present invention is not limited to the following embodiments.

[0240] (Example 1)

[0241] [Formation of Layered Structures]

[0242] A stacked structure as described in Example 1 was fabricated. The stacked structure of Example 1 is the one described above used in Embodiment 1. Figure 3 The layered structure described.

[0243] First, the substrate 11 (refer to) is subjected to reactive ion etching (RIE). Figure 3 The Si(111) substrate is crystallized on one side of the growth surface and heated in the presence of oxygen to form a thermal oxide film. Then, without using oxygen, the metal (Hf, Zr, Y) of the evaporation source reacts thermally with the oxygen in the oxide film on the Si substrate using molecular beam epitaxy (MBE). This reaction is used as a buffer film 12 (see reference). Figure 3 An orientation film of the first metal oxide is formed on a Si substrate. Furthermore, the Hf:Zr:Y (atomic ratio, the same below) value is 22.5:67.5:10, as per the target value.

[0244] Evaporation sources: Hf, Zr, Y

[0245] Pressure: 2×10 -4 Pa

[0246] Thickness: 5nm

[0247] Substrate temperature: 1000℃

[0248] Next, oxygen is introduced, the temperature is lowered and the pressure is increased, and then the buffer membrane 13 (see reference) is used by the MBE method. Figure 3 A second metal oxide oriented film is formed. The conditions for this film formation using the MBE method are described below. Furthermore, the Hf:Zr value is a target of 25:75.

[0249] Evaporation sources: Hf, Zr

[0250] Pressure: 2×10 -2 Pa

[0251] Thickness: 95nm

[0252] Substrate temperature: 900℃

[0253] Next, the piezoelectric film 14 composed of AlN (refer to) is sputtered. Figure 3 ) Formed on buffer membrane 13 (refer to Figure 3 The laminated structure of Example 1 was thus fabricated on the piezoelectric film 14. The conditions for forming this piezoelectric film 14 are shown below.

[0254] Equipment: RF sputtering equipment

[0255] Pressure: 1-2 Pa

[0256] Target material: Al

[0257] Gas: Ar / N2

[0258] Electricity: 2500~3500W (AC)

[0259] Substrate temperature: 350~450℃

[0260] Thickness: 100nm

[0261] Thus, the piezoelectric film 14 is formed on the buffer film 13 by sputtering, thereby creating the laminated structure of Example 1.

[0262] X-ray diffraction measurement

[0263] After buffer films 12 and 13 were formed on the main surface 11p of substrate 11, and before the piezoelectric film 14 was formed, the diffraction pattern of the stacked structure was measured by X-ray diffraction (XRD) with the diffraction plane parallel to the main surface 11p. The measured diffraction pattern of the stacked structure of Example 1 is shown below. Figure 12 XRD measurements were performed using the SmartLab X-ray diffraction apparatus manufactured by Rigaku Corporation.

[0264] like Figure 12As shown, in this diffraction pattern, strong diffraction peaks were observed on the tetragonal (101) plane of YHZO (YHZOt(101)) and the tetragonal (202) plane (YHZOt(202)), or on the tetragonal (101) plane and the tetragonal (202) plane of HZO. Furthermore, when YHZO and HZO have a tetragonal crystal structure, the lattice constant of the a-axis is approximately 1 / (2π) of the lattice constant of the c-axis. 1 / 2 ) times. In this case, it can be known that the YHZO contained in the first metal oxide having a tetragonal crystal structure and a (101) orientation has a (111) orientation when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide having a tetragonal crystal structure and a (101) orientation has a (111) orientation when represented as a pseudocubic crystal. Furthermore, it can be known that the YHZO contained in the first metal oxide has a tetragonal crystal structure and a (101) orientation, and the HZO contained in the second metal oxide has a tetragonal crystal structure and a (101) orientation.

[0265] Furthermore, after forming the piezoelectric film 14, the diffraction pattern of the resulting laminated structure of Example 1 was measured by X-ray diffraction with the diffraction plane parallel to the principal plane 11p in an X-ray diffraction measurement using the θ-2θ method. The measured diffraction pattern of the laminated structure of Example 1 is shown below. Figure 13 .

[0266] like Figure 13 As shown, a strong diffraction peak of the (0002) plane of AlN was observed in the diffraction pattern of Example 1. Therefore, in Example 1, it can be seen that the AlN contained in the piezoelectric film 14 has a hexagonal crystal structure and is oriented in (0001).

[0267] (Example 2)

[0268] Next, except that a Si(100) substrate was used instead of a Si(111) substrate as substrate 11 and a piezoelectric film 14 was not formed on buffer film 13, the stacked structure of Example 2 was fabricated in the same manner as in Example 1.

[0269] For the stacked structure of Example 2, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 2 is shown below. Figure 14 .exist Figure 14In this context, the cubic (200) plane is denoted as "c200", and the monoclinic (200) plane is denoted as "m200" (including the orthorhombic (200) plane as "o200", the tetragonal (200) plane as "t200", the monoclinic (11-1) plane as "m11-1", and the monoclinic (111) plane as "m111", which will be discussed later). Figure 15 , Figures 17 to 27 (The same applies to China).

[0270] like Figure 14 As shown, strong diffraction peaks were observed in the cubic (200) plane and monoclinic (200) plane of YHZO, as well as strong diffraction peaks in the cubic (200) plane and monoclinic (200) plane of HZO. Therefore, it can be concluded that the YHZO contained in the first metal oxide is oriented (100) when represented as pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (100) when represented as pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si (100) substrate or the SOI layer is composed of a Si (100) film, it can be concluded that the first metal oxide has a cubic crystal structure and is oriented (100), or has a monoclinic crystal structure and is oriented (100), and the second metal oxide has a cubic crystal structure and is oriented (100), or has a monoclinic crystal structure and is oriented (100).

[0271] (Example 3)

[0272] Next, except that the Hf:Zr:Y (atomic ratio, the same below) value is 20:60:20 as the target value, a Si(100) substrate is used instead of a Si(111) substrate as substrate 11, and a piezoelectric film 14 is not formed on the buffer film 13, the stacked structure of Example 3 was fabricated in the same way as in Example 1.

[0273] For the stacked structure of Example 3, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 3 is shown below. Figure 15 .

[0274] like Figure 15As shown, strong diffraction peaks were observed on the cubic (200) plane of YHZO and on the cubic (200) plane of HZO in the diffraction pattern. Therefore, it can be concluded that the YHZO contained in the first metal oxide is oriented (100) when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (100) when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si (100) substrate or the SOI layer is composed of a Si (100) film, it can be concluded that the first metal oxide has a cubic crystal structure and is oriented (100), and the second metal oxide has a cubic crystal structure and is oriented (100).

[0275] Furthermore, with the stacked structure configured in an in-plane measurement (where the diffraction plane is tilted 90° relative to the principal plane 11p), φ scans were performed on the cubic (200) planes of YHZO and HZO (2θ = 35°) contained in the metal oxide. The φ scans measured on the stacked structure of Example 3 are shown below. Figure 16 .

[0276] like Figure 16 As shown, in this φ scan, four strong diffraction peaks were observed at 90° intervals on the cubic (200) plane of YHZO and the cubic (200) plane of HZO. That is, in this φ scan, four symmetrical diffraction peaks were observed for YHZO and HZO. Therefore, it can be concluded that the crystal axes of YHZO contained in the first metal oxide and HZO contained in the second metal oxide are also consistent in the in-plane direction along the main plane 11p of the substrate 11, indicating that epitaxial growth has been performed.

[0277] (Example 4)

[0278] Next, except that a Si(100) substrate was used instead of a Si(111) substrate as substrate 11 and a piezoelectric film 14 was not formed on buffer film 13, the stacked structure of Example 4 was fabricated in the same manner as in Example 1.

[0279] For the stacked structure of Example 4, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 4 is shown below. Figure 17 .

[0280] like Figure 17As shown, strong diffraction peaks were observed on the monoclinic (11-1) plane of YHZO and HZO in the diffraction pattern. Therefore, it can be concluded that the YHZO contained in the first metal oxide is oriented (111) when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (111) when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si (100) substrate or the SOI layer is composed of a Si (100) film, it can be concluded that the first metal oxide has a monoclinic crystal structure and is oriented (11-1), and the second metal oxide has a monoclinic crystal structure and is oriented (11-1).

[0281] (Example 5)

[0282] Next, except that Al was used as M instead of Y (the Hf:Zr:Al (atomic ratio, the same below) was 20:60:20 based on the target value) and no piezoelectric film 14 was formed on the buffer film 13, the laminated structure of Example 5 was fabricated in the same manner as in Example 1. When Al was used as M instead of Y, the first metal oxide was referred to as Al2O3-HZO. Al2O3-HZO is a material in which ZrO2 or HfO2 contained in HZO is stabilized by Al2O3.

[0283] For the stacked structure of Example 5, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 5 is shown below. Figure 18 .

[0284] like Figure 18 As shown, in this diffraction pattern, strong diffraction peaks were observed on the monoclinic (111) plane of Al2O3-HZO and the monoclinic (11-1) plane of HZO. Therefore, it can be concluded that the Al2O3-HZO contained in the first metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(111) substrate or the SOI layer is composed of a Si(111) film, it can be known that the first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0285] (Example 6)

[0286] Next, except that Si was used to replace Y as M (the Hf:Zr:Si atomic ratio was 22.5:67.5:10 as per the target value), a Si(100) substrate was used to replace the Si(111) substrate as substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13, the laminated structure of Example 6 was fabricated in the same manner as in Example 1. When Si was used to replace Y as M, the first metal oxide was referred to as SiO2-HZO. SiO2-HZO is a material in which ZrO2 or HfO2 contained in HZO is stabilized by SiO2.

[0287] For the stacked structure of Example 6, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 6 is shown below. Figure 19 .

[0288] like Figure 19 As shown, in this diffraction pattern, strong diffraction peaks were observed in the cubic (200) plane of SiO2-HZO, the monoclinic (200) plane, and the orthorhombic (200) plane, as well as in the cubic (200) plane of HZO. Therefore, it can be concluded that the SiO2-HZO contained in the first metal oxide is oriented (100) when represented by pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (100) when represented by pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(100) substrate or the SOI layer is composed of a Si(100) film, it can be known that the first metal oxide has a cubic crystal structure and is (100) oriented, or has a monoclinic crystal structure and is (100) oriented, or has an orthorhombic crystal structure and is (100) oriented, and the second metal oxide has a cubic crystal structure and is (100) oriented, or has a monoclinic crystal structure and is (100) oriented, or has an orthorhombic crystal structure and is (100) oriented.

[0289] In the stacked structure of Example 6, the Si contained in SiO2-HZO is easily etched using alkaline etching solution, thus the buffer film 12 can be easily removed or processed (the same applies to the stacked structure of Example 7 described later).

[0290] (Example 7)

[0291] Next, except that Si was used to replace Y as M (the Hf:Zr:Si value is 20:60:20 as the target value), a Si(100) substrate was used to replace the Si(111) substrate as substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13, the stacked structure of Example 7 was fabricated in the same manner as in Example 1. In Example 7, as in Example 6, the first metal oxide was referred to as SiO2-HZO.

[0292] For the stacked structure of Example 7, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 7 is shown below. Figure 20 .

[0293] like Figure 20 As shown, strong diffraction peaks were observed in the cubic (200) plane and tetragonal (002) plane of SiO2-HZO, as well as strong diffraction peaks in the cubic (200) plane and tetragonal (002) plane of HZO. Therefore, it can be concluded that the SiO2-HZO contained in the first metal oxide is oriented (100) when represented as pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (100) when represented as pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(100) substrate or the SOI layer is composed of a Si(100) film, it can be known that the first metal oxide has a cubic crystal structure and is (100) oriented, or has a tetragonal crystal structure and is (001) oriented, and the second metal oxide has a cubic crystal structure and is (100) oriented, or has a tetragonal crystal structure and is (001) oriented.

[0294] (Example 8)

[0295] Next, except that magnesium (Mg) was used to replace Y as M (the atomic ratio of Hf:Zr:Mg was 22.5:67.5:10 as the target value), a Si (100) substrate was used to replace the Si (111) substrate as substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13, the laminated structure of Example 8 was fabricated in the same manner as in Example 1. In Example 8, the first metal oxide is referred to as MHZO. MHZO is a material in which ZrO2 or HfO2 contained in HZO is stabilized by MgO.

[0296] For the stacked structure of Example 8, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 8 is shown below. Figure 21 .

[0297] like Figure 21 As shown, strong diffraction peaks were observed in the cubic (200) plane and monoclinic (200) plane of MHZO, as well as strong diffraction peaks in the cubic (200) plane and monoclinic (200) plane of HZO. Therefore, it can be concluded that the MHZO contained in the first metal oxide is oriented (100) when represented by pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (100) when represented by pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si (100) substrate or the SOI layer is composed of a Si (100) film, it can be concluded that the first metal oxide has a cubic crystal structure and is oriented (100), or has a monoclinic crystal structure and is oriented (100), and the second metal oxide has a cubic crystal structure and is oriented (100), or has a monoclinic crystal structure and is oriented (100).

[0298] In the laminated structure of Example 8, by including MgO in HZO, the Young's modulus of HZO can be increased by, for example, several times to about 10 times (the same applies to the laminated structure of Example 9 described later).

[0299] In the stacked structure of Example 8, after a conductive film made of Pt and a conductive film made of iron (Fe) were sequentially stacked on the buffer film 13, the stacked structure was configured such that the diffraction plane was parallel to the principal plane 11p in XRD measurement using the θ-2θ method. The diffraction pattern of the stacked structure was then measured by X-ray diffraction. The measured diffraction pattern of the stacked structure of Example 8 is shown below. Figure 22 .

[0300] like Figure 22 As shown, in this diffraction pattern, besides Figure 21 In addition to the diffraction peaks of MHZO and HZO shown, strong diffraction peaks were also observed on the cubic (200) plane of Pt and the cubic (200) plane of Fe. Therefore, it can be concluded that the conductive film composed of Pt has a cubic crystal structure and is oriented at (100), and the conductive film composed of Fe has a cubic crystal structure and is oriented at (100).

[0301] (Example 9)

[0302] Next, except that Mg was used to replace Y as M (the Hf:Zr:Mg value was 22.5:67.5:10 as the target value) and no piezoelectric film 14 was formed on the buffer film 13, the laminated structure of Example 9 was fabricated in the same manner as in Example 1. In Example 9, the first metal oxide was referred to as MHZO, as in Example 8.

[0303] For the stacked structure of Example 9, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 9 is shown below. Figure 23 .

[0304] like Figure 23 As shown, strong diffraction peaks were observed in the monoclinic (111) plane of MHZO and in the monoclinic (11-1) plane of HZO. Therefore, it can be concluded that the MHZO contained in the first metal oxide is oriented (111) when represented by a pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (111) when represented by a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si (111) substrate or the SOI layer is composed of a Si (111) film, it can be concluded that the first metal oxide has a monoclinic crystal structure and is oriented (111), or has a monoclinic crystal structure and is oriented (11-1), and the second metal oxide has a monoclinic crystal structure and is oriented (111), or has a monoclinic crystal structure and is oriented (11-1).

[0305] In the stacked structure of Example 9, after a conductive film made of Pt and a conductive film made of iron (Fe) were sequentially stacked on the buffer film 13, the stacked structure was configured such that the diffraction plane was parallel to the principal plane 11p in XRD measurement using the θ-2θ method. The diffraction pattern of the stacked structure was then measured by X-ray diffraction. The measured diffraction pattern of the stacked structure of Example 9 is shown below. Figure 24 .

[0306] like Figure 24 As shown, in this diffraction pattern, besides Figure 23 In addition to the diffraction peaks of MHZO and HZO shown, strong diffraction peaks were also observed on the cubic (111) plane of Pt and the cubic (110) plane of Fe. Therefore, it can be concluded that the conductive film composed of Pt has a cubic crystal structure with a (111) orientation, and the conductive film composed of Fe has a cubic crystal structure with a (110) orientation.

[0307] (Example 10)

[0308] Next, except that titanium (Ti) was used to replace Y as M (the atomic ratio of Hf:Zr:Ti was 22.5:67.5:10 as the target value), a Si (100) substrate was used to replace the Si (111) substrate as substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13, the laminated structure of Example 10 was fabricated in the same manner as in Example 1. In Example 10, the first metal oxide was referred to as TiO2-HZO. TiO2-HZO is a material in which the ZrO2 or HfO2 contained in HZO is stabilized by TiO2.

[0309] For the stacked structure of Example 10, with the stacked structure configured such that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 10 is shown below. Figure 25 .

[0310] like Figure 25 As shown, strong diffraction peaks were observed in the cubic (200) plane of TiO2-HZO and the monoclinic (200) plane of HZO. Therefore, it can be concluded that the TiO2-HZO contained in the first metal oxide is oriented (100) when represented as pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (100) when represented as pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(100) substrate or the SOI layer is composed of a Si(100) film, it can be known that the first metal oxide has a cubic crystal structure and is (100) oriented, or has a monoclinic crystal structure and is (100) oriented, and the second metal oxide has a cubic crystal structure and is (100) oriented, or has a monoclinic crystal structure and is (100) oriented.

[0311] (Example 11)

[0312] Next, except that lanthanum (La) was used to replace Y as M (the atomic ratio of Hf:Zr:La is 20:60:20 based on the target value) and no piezoelectric film 14 was formed on the buffer film 13, the laminated structure of Example 11 was fabricated in the same manner as in Example 1. In Example 11, the first metal oxide was referred to as La2O3-HZO. La2O3-HZO is a material in which the ZrO2 or HfO2 contained in HZO is stabilized by La2O3.

[0313] For the stacked structure of Example 11, with the stacked structure configured such that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 11 is shown below. Figure 26 .

[0314] like Figure 26 As shown, in this diffraction pattern, strong diffraction peaks were observed on the monoclinic (111) plane of La2O3-HZO and the monoclinic (11-1) plane of HZO. Therefore, it can be concluded that the La2O3-HZO contained in the first metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(111) substrate or the SOI layer is composed of a Si(111) film, it can be known that the first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0315] (Example 12)

[0316] Next, except that niobium (Nb) was used to replace Y as M (the atomic ratio of Hf:Zr:Nb is 22.5:67.5:10 based on the target value), and a piezoelectric film 14 was not formed on the buffer film 13, the laminated structure of Example 12 was fabricated in the same manner as in Example 1. In Example 12, the first metal oxide was referred to as Nb2O5-HZO. Nb2O5-HZO is a material in which the ZrO2 or HfO2 contained in HZO is stabilized by Nb2O5.

[0317] For the stacked structure of Example 12, with the stacked structure configured such that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 12 is shown below. Figure 27 .

[0318] like Figure 27As shown, in this diffraction pattern, strong diffraction peaks were observed on the monoclinic (111) plane of Nb₂O₅-HZO and the monoclinic (11-1) plane of HZO. Therefore, it can be concluded that the Nb₂O₅-HZO contained in the first metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(111) substrate or the SOI layer is composed of a Si(111) film, it can be known that the first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0319] (Example 13)

[0320] Next, except that the Hf:Zr:Y (atomic ratio, the same below) value is 22.5:67.5:10 as the target value, and the piezoelectric film 14 is not formed on the buffer film 13, the same as in Example 1 was used to fabricate the stacked structure of Example 13, such as using a Si(111) substrate as the substrate 11.

[0321] For the stacked structure of Example 13, with the stacked structure configured such that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 13 is shown below. Figure 28 .exist Figure 28 In this context, the monoclinic (11-1) plane is denoted as "m11-1", and the monoclinic (111) plane is denoted as "m111" (including the cubic (200) plane being denoted as "c200" and the tetragonal (002) plane being denoted as "t200", which will be discussed later). Figures 29 to 34 (The same applies to China).

[0322] like Figure 28As shown, strong diffraction peaks were observed on the monoclinic (111) plane and the monoclinic (11-1) plane of YHZO, as well as on the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, it can be concluded that the YHZO contained in the first metal oxide is oriented (111) when represented by pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (111) when represented by pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(111) substrate or the SOI layer is composed of a Si(111) film, it can be known that the first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0323] (Example 14)

[0324] Next, except that the Hf:Zr:Y (atomic ratio, the same below) value is 20:60:20 as the target value and the piezoelectric film 14 is not formed on the buffer film 13, the same as in Example 1, such as using a Si(111) substrate as the substrate 11, the stacked structure of Example 14 was fabricated.

[0325] For the stacked structure of Example 14, with the stacked structure configured such that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 14 is shown below. Figure 29 .

[0326] like Figure 29 As shown, strong diffraction peaks were observed on the monoclinic (111) plane and the monoclinic (11-1) plane of YHZO, as well as on the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, it can be concluded that the YHZO contained in the first metal oxide is oriented (111) when represented by pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (111) when represented by pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(111) substrate or the SOI layer is composed of a Si(111) film, it can be known that the first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0327] (Example 15)

[0328] Next, except that Si was used to replace Y as M (the Hf:Zr:Si atomic ratio, hereinafter the same) was 22.5:67.5:10 as the target value, and no piezoelectric film 14 was formed on the buffer film 13, the laminated structure of Example 15 was fabricated in the same manner as in Example 1, such as using a Si(111) substrate as substrate 11. When Si was used to replace Y as M, the first metal oxide was referred to as SiO2-HZO. SiO2-HZO is a material in which ZrO2 or HfO2 contained in HZO is stabilized by SiO2.

[0329] For the stacked structure of Example 15, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 15 is shown below. Figure 30 .

[0330] like Figure 30 As shown, strong diffraction peaks were observed on the monoclinic (111) plane and the monoclinic (11-1) plane of SiO2-HZO, as well as on the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, it can be concluded that the SiO2-HZO contained in the first metal oxide is oriented (111) when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (111) when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(111) substrate or the SOI layer is composed of a Si(111) film, it can be known that the first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0331] As mentioned above, in the stacked structure of Example 15, the Si contained in SiO2-HZO is easily etched using alkaline etching solution, thus the buffer film 12 can be easily removed or processed.

[0332] (Example 16)

[0333] Next, except that Ce was used to replace Y as M (the atomic ratio of Hf:Zr:Ce was 22.5:67.5:10 based on the target value) and no piezoelectric film 14 was formed on the buffer film 13, the laminated structure of Example 16 was fabricated in the same manner as in Example 1, such as using a Si(111) substrate as substrate 11. When Ce was used to replace Y as M, the first metal oxide was referred to as CeO2-HZO. CeO2-HZO is a material in which ZrO2 or HfO2 contained in HZO is stabilized by CeO2.

[0334] For the stacked structure of Example 16, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 16 is shown below. Figure 31 .

[0335] like Figure 31 As shown, strong diffraction peaks were observed on the monoclinic (111) plane of CeO2-HZO and the monoclinic (11-1) plane of HZO. Therefore, it can be concluded that the CeO2-HZO contained in the first metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(111) substrate or the SOI layer is composed of a Si(111) film, it can be known that the first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0336] (Example 17)

[0337] Next, except that Ti was used to replace Y as M (the atomic ratio of Hf:Zr:Ti is 20:60:20 as the target value) and no piezoelectric film 14 was formed on the buffer film 13, the laminated structure of Example 17 was fabricated in the same manner as in Example 1, such as using a Si(111) substrate as substrate 11. In Example 17, the first metal oxide is referred to as TiO2-HZO. TiO2-HZO is a material in which the ZrO2 or HfO2 contained in HZO is stabilized by TiO2.

[0338] For the stacked structure of Example 17, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 17 is shown below. Figure 32 .

[0339] like Figure 32 As shown, in this diffraction pattern, strong diffraction peaks were observed on the monoclinic (111) plane of TiO2-HZO and the monoclinic (11-1) plane of HZO. Therefore, it can be concluded that the TiO2-HZO contained in the first metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(111) substrate or the SOI layer is composed of a Si(111) film, it can be known that the first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0340] (Example 18)

[0341] Next, except that Ta was used to replace Y as M (the value of Hf:Zr:Ta (atomic ratio, the same below) was 22.5:67.5:10 based on the target value), and no piezoelectric film 14 was formed on the buffer film 13, the laminated structure of Example 18 was fabricated in the same manner as in Example 1, such as using a Si(111) substrate as substrate 11. In Example 18, the first metal oxide was referred to as Ta2O5-HZO. Ta2O5-HZO is a material in which ZrO2 or HfO2 contained in HZO is stabilized by Ta2O5.

[0342] For the stacked structure of Example 18, with the stacked structure configured so that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 18 is shown below. Figure 33 .

[0343] like Figure 33As shown, in this diffraction pattern, strong diffraction peaks were observed on the monoclinic (111) plane of Ta2O5-HZO and the monoclinic (11-1) plane, as well as on the monoclinic (111) plane of HZO. Therefore, it can be concluded that the Ta2O5-HZO contained in the first metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide exhibits a (111) orientation when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si(111) substrate or the SOI layer is composed of a Si(111) film, it can be known that the first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0344] (Example 19)

[0345] Next, except that Ca was used to replace Y as M (the atomic ratio of Hf:Zr:Ca was 20:60:20 as the target value), Si(100) substrate was used to replace Si(111) substrate as substrate 11, and no piezoelectric film 14 was formed on buffer film 13, the laminated structure of Example 19 was fabricated in the same manner as in Example 1. In Example 19, the first metal oxide is referred to as CaO-HZO. CaO-HZO is a material in which ZrO2 or HfO2 contained in HZO is stabilized by CaO.

[0346] For the stacked structure of Example 19, with the stacked structure configured such that the diffraction plane is parallel to the principal plane 11p in XRD measurements using the θ-2θ method, the diffraction pattern of the stacked structure was measured using this X-ray diffraction method. The measured diffraction pattern of the stacked structure of Example 19 is shown below. Figure 34 .

[0347] like Figure 34 As shown, strong diffraction peaks were observed on the cubic (200) plane and the tetragonal (002) plane of CaO-HZO in the diffraction pattern. Therefore, it can be concluded that the YHZO contained in the first metal oxide is oriented (100) when represented as a pseudocubic crystal, and the HZO contained in the second metal oxide is oriented (100) when represented as a pseudocubic crystal. Furthermore, when the Si substrate is composed of a Si (100) substrate or the SOI layer is composed of a Si (100) film, it can be concluded that the first metal oxide has a cubic crystal structure and is oriented (100), or has a tetragonal crystal structure and is oriented (001), and the second metal oxide has a cubic crystal structure and is oriented (100), or has a tetragonal crystal structure and is oriented (001).

[0348] Although detailed descriptions are omitted, in any of Examples 1 to 19, in the first metal oxide, the ratio of Hf:Zr:M (atomic ratio, the same below) is other than 22.5:67.5:10 and 20:60:20, and y1 in the above composition formula (1) or above composition formula (3) satisfies 0 < y1 ≤ 0.3 and x1 satisfies 0 ≤ x1 ≤ 1 - y1. The same results were obtained as in the examples where the ratio of Hf:Zr:M is 22.5:67.5:10 (x1 is 0.675 and y1 is 0.10 in the above composition formula (1) or above composition formula (3)) or 20:60:20 (x1 is 0.60 and y1 is 0.20 in the above composition formula (1) or above composition formula (3).

[0349] Furthermore, although detailed descriptions are omitted, in any of Examples 1 to 19, in the second metal oxide, the ratio of Hf:Zr (atomic ratio, the same below) is other than 25:75, and x2 of the above composition formula (2) or the above composition formula (4) satisfies 0≤x2<1 or satisfies x2=1, the same results were obtained as in the examples where the ratio of Hf:Zr is 25:75 (x2 of the above composition formula (2) or the above composition formula (4) is 0.75).

[0350] (Example 20)

[0351] [Formation of Layered Structures]

[0352] Next, except that Si was used to replace Y as M (the Hf:Zr:Si atomic ratio is 20:60:20 as the target value), a Si(100) substrate was used to replace the Si(111) substrate as substrate 11, a buffer film 12 was formed but a buffer film 13 was not formed, and a semiconductor film 31 was formed on the buffer film 12 instead of the piezoelectric film 14, the stacked structure of Example 20 was fabricated in the same manner as in Example 1. When Si is used to replace Y as M, the metal oxide is referred to as SiO2-HZO or SHZO. SiO2-HZO or SHZO is a material in which ZrO2 or HfO2 contained in HZO is stabilized by SiO2.

[0353] First, the substrate 11 (reference) is subjected to RIE. Figure 8 The Si(100) substrate is crystallized on one side of the growth surface and heated in the presence of oxygen to form a thermal oxide film. Then, without using oxygen, the metal (Hf, Zr, Si) of the evaporation source is thermally reacted with the oxygen in the oxide film on the Si substrate by the MBE method, and a buffer film 12 (refer to) is used. Figure 8An oriented film of metal oxide (Hf:Zr:Si) is formed on a Si substrate. Furthermore, the atomic ratio of Hf:Zr:Si is 20:60:20 (target value).

[0354] Evaporation sources: Hf, Zr, Si

[0355] Pressure: 2×10 -4 Pa

[0356] Thickness: 5nm

[0357] Substrate temperature: 1000℃

[0358] Next, oxygen is introduced, the temperature is lowered and the pressure is increased, and then the buffer membrane 12 (refer to) is used by the MBE method. Figure 8 The orientation film of the metal oxide continues to be formed. The conditions of the MBE method during this film formation are as follows. In addition, the value of Hf:Zr:Si (atomic ratio, the same below) is 20:60:20 as the target value.

[0359] Evaporation sources: Hf, Zr, Si

[0360] Pressure: 2×10 -2 Pa

[0361] Thickness: 95nm

[0362] Substrate temperature: 900℃

[0363] Next, the semiconductor film 31 (refer to) made of Si is subjected to the MBE method. Figure 8 ) Formed on buffer membrane 12 (refer to Figure 8 The semiconductor film was fabricated on a substrate, thus creating the stacked structure of Example 20. The conditions for forming the semiconductor film are shown below.

[0364] Evaporation source: Si

[0365] Pressure: 2×10 -4 Pa

[0366] Thickness: 100nm

[0367] Substrate temperature: 700~900℃

[0368] Thus, the semiconductor film was formed on the buffer film 12 by the MBE method, thereby creating the stacked structure of Example 20.

[0369] X-ray diffraction measurement

[0370] After the buffer film 12 is formed on the main surface 11p of the substrate 11, and before the semiconductor film is formed, the diffraction pattern of the stacked structure is measured by X-ray diffraction with the diffraction plane parallel to the main surface 11p in XRD measurement using the θ-2θ method. The measured diffraction pattern of the stacked structure of Example 20 is shown below. Figure 35 .

[0371] like Figure 35 As shown, in this diffraction pattern, strong diffraction peaks were observed on the cubic (200) plane of SHZO (SHZOc(200)), the cubic (400) plane of SHZO (SHZOc(400)), the tetragonal (002) plane of SHZO (SHZOt(002)), and the tetragonal (004) plane of SHZO (SHZOt(004)). In this case, it can be concluded that the metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation.

[0372] Furthermore, after forming the semiconductor film 31, the diffraction pattern of the resulting stacked structure of Example 20 was measured using X-ray diffraction with the diffraction plane parallel to the principal plane 11p in an out-of-plane measurement. The measured diffraction pattern of the stacked structure of Example 20 is shown below. Figure 36 .

[0373] like Figure 36 As shown, in the diffraction pattern (out-of-plane measurement) of Example 20, a strong diffraction peak (SHZO c(200)) of the cubic (200) plane of SHZO was observed. In this case, it can be known that the metal oxide has a cubic crystal structure and is oriented at (100). Furthermore, since the diffraction peak of the tetragonal (002) plane of SHZO, which was observed before the formation of the semiconductor film 31, was not observed, it can be known that the crystal structure of the buffer film 12 changes due to the martensitic phase transformation caused by the formation of the semiconductor film 31.

[0374] Furthermore, after forming the semiconductor film 31, the semiconductor film 31 was irradiated with incident X-rays. The resulting stacked structure of Example 20 was then measured using X-ray diffraction with the diffraction plane tilted at 90° relative to the principal plane 11p in an in-plane X-ray diffraction measurement employing the θ-2θ method. The diffraction pattern of the uppermost layer of the stacked structure of Example 20 is shown below. Figure 37.

[0375] like Figure 37 As shown, in the diffraction pattern (in-plane measurement) of Example 20, a strong diffraction peak (Si(220)) of the cubic crystal (220) plane of Si was observed. In this case, it can be determined that the semiconductor film 31 contains Si.

[0376] After measuring Figure 37 Following the diffraction pattern shown (in-plane measurement), a φ scan was performed on the cubic (220) plane (2θ = 47°) of Si contained in the semiconductor film 31, with the stacked structure arranged in a manner where the diffraction plane in the X-ray diffraction measurement was tilted at 90° relative to the principal plane 11p (in-plane measurement). Furthermore, with the substrate 11 irradiated by incident X-rays, a φ scan was performed on the cubic (220) plane (2θ = 47°) of Si contained in the substrate 11, with the tilt angle of the diffraction plane in the X-ray diffraction measurement slightly deviated from 90° relative to the principal plane 11p. The φ scans measured on the semiconductor film 31 and substrate 11 of the stacked structure of Example 20 are shown below. Figure 38 . Figure 38 The chart on the top shows the φ scan of semiconductor film 31. Figure 38 The chart below shows the φ scan of substrate 11.

[0377] like Figure 36 As shown, in this diffraction pattern (out-of-plane), only a strong peak was observed on the Si(400) plane for Si. Furthermore, as... Figure 38 As shown in the chart below, four strong diffraction peaks were observed at 90° intervals on the cubic (220) plane of the Si contained in substrate 11 during this φ scan. That is, four symmetrical diffraction peaks were observed in the Si contained in substrate 11 during this φ scan. Furthermore, as... Figure 38 As shown in the graph above, in this φ scan, four strong diffraction peaks were observed at 90° intervals on the cubic (220) plane of the Si contained in the semiconductor film 31. That is, in this φ scan, four symmetrical diffraction peaks were observed in the Si contained in the semiconductor film 31. Furthermore, in comparison... Figure 38 The chart on the top and Figure 38 In the diagram below, the angles of the four strong diffraction peaks of the cubic (220) plane of Si contained in the semiconductor film 31 are close to any one of the angles of the four strong diffraction peaks of the cubic (220) plane of Si contained in the substrate 11.

[0378] Therefore, it can be determined that the Si contained in the semiconductor film 31 has a cubic crystal structure and is oriented at (100), and that the crystal axis of the Si contained in the semiconductor film 31 is also aligned in the in-plane direction along the main surface 11p of the substrate 11, i.e., epitaxial growth has been performed. Furthermore, it can be determined that the semiconductor film 31 is oriented such that the <100> direction along the main surface 11p of the semiconductor film 31 is aligned with the <100> direction along the main surface 11p of the Si contained in the substrate 11. Figure 38 As shown, the angle between the <100> direction along the main surface 11p of the semiconductor film 31 and the <100> direction along the main surface 11p of the Si contained in the substrate 11 is 1.76°.

[0379] Furthermore, although not illustrated, a φ scan was performed on the cubic (220) plane (2θ = 50°) of SHZO contained in the buffer film 12, with the incident X-rays irradiating the buffer film 12 and the diffraction plane in the X-ray diffraction measurement slightly deviated from the tilt angle of the main plane 11p from 90°. As a result, in this φ scan, four symmetrical diffraction peaks were observed in the SHZO contained in the buffer film 12. Furthermore, in this φ scan, four strong diffraction peaks were observed in the cubic (220) plane of SHZO contained in the buffer film 12 at 90° intervals. That is, four symmetrical diffraction peaks were observed in the φ scan. Moreover, the angles of the four strong diffraction peaks in the cubic (220) plane of SHZO contained in the buffer film 12 are close to any one of the angles of the four strong diffraction peaks in the cubic (220) plane of Si contained in the substrate 11.

[0380] Therefore, it can be known that the SHZO contained in the buffer film 12 has a cubic crystal structure and is oriented at (100), and that the crystal axis of the SHZO contained in the buffer film 12 is also consistent in the in-plane direction along the principal plane 11p of the substrate 11, i.e., epitaxial growth has been performed. Furthermore, it can be known that the buffer film 12 is oriented in such a way that when represented as a pseudocubic crystal, it is oriented along the <100> direction of the principal plane 11p of the metal oxide in the manner of the <100> direction along the principal plane 11p of the Si contained in the substrate 11.

[0381] Although detailed descriptions are omitted, in the stacked structures of Embodiments 6 and 7, which replace the stacked structure of Embodiment 20, a semiconductor film 31 containing Si can also be formed on the buffer film 13, and the results are substantially the same as those of Embodiment 20.

[0382] (Example 21)

[0383] Next, in addition to forming a semiconductor film 31 made of SiGe as the semiconductor film 31 (see reference 31), Figure 8Except for replacing the semiconductor film 31 made of Si, the stacked structure of Example 21 was fabricated in the same manner as in Example 20. The Si:Ge (atomic ratio, the same below) value when the semiconductor film 31 was formed by the MBE method was 75:25 as the target value.

[0384] After the buffer film 12 is formed on the main surface 11p of the substrate 11 and before the semiconductor film 31 is formed, the diffraction pattern of the stacked structure is measured by X-ray diffraction with the diffraction plane parallel to the main surface 11p in XRD measurement using the θ-2θ method. Although the results are not illustrated, they are similar to those obtained in the XRD method. Figure 35 The same result was obtained. That is, it can be known that the metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation.

[0385] Furthermore, after forming the semiconductor film 31, the diffraction pattern of the resulting stacked structure of Example 21 was measured using X-ray diffraction with the diffraction plane parallel to the principal plane 11p in an out-of-plane X-ray diffraction measurement. The measured diffraction pattern of the stacked structure of Example 21 is shown below. Figure 39 .

[0386] like Figure 39 As shown, in the diffraction pattern (out-of-plane measurement) of Example 21, strong diffraction peaks were observed on the cubic (200) plane of SHZO (SHZO c(200)), the cubic (400) plane of SHZO (SHZO c(400)), and the tetragonal (002) plane of SHZO (SHZO t(002)). In this case, it can be concluded that the metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation.

[0387] Furthermore, after forming the semiconductor film 31, the semiconductor film 31 was irradiated with incident X-rays. The resulting stacked structure of Example 21 was then measured using an in-plane X-ray diffraction method, where the diffraction plane was tilted 90° relative to the principal plane 11p. The diffraction pattern of the uppermost layer of the stacked structure of Example 21 was determined by this X-ray diffraction measurement. The measured diffraction pattern of the stacked structure of Example 21 is shown below. Figure 40 .

[0388] like Figure 40As shown, in the diffraction pattern (in-plane measurement) of Example 21, a strong diffraction peak (SiGe(220)) of the cubic crystal (220) plane of SiGe was observed. In this case, it can be determined that the semiconductor film 31 contains SiGe.

[0389] After measuring Figure 40 Following the diffraction pattern shown (in-plane measurement), a φ scan was performed on the cubic (220) plane (2θ = 47°) of SiGe contained in the semiconductor film 31, with the stacked structure configured such that the diffraction plane in the X-ray diffraction measurement was tilted at 90° relative to the principal plane 11p (in-plane measurement). Furthermore, a φ scan was performed on the cubic (220) plane (2θ = 47°) of Si contained in the substrate 11, with the substrate 11 irradiated by incident X-rays and the tilt angle of the diffraction plane in the X-ray diffraction measurement relative to the principal plane 11p slightly deviated from 90°. The φ scans measured on the semiconductor film 31 and substrate 11 of the stacked structure of Example 21 are shown below. Figure 41 . Figure 41 The chart on the top shows the φ scan of semiconductor film 31. Figure 41 The chart below shows the φ scan of substrate 11.

[0390] like Figure 39 As shown, in this diffraction pattern (out-of-plane), only a strong peak was observed on the Si(400) plane for Si. Furthermore, as... Figure 41 As shown in the chart below, four strong diffraction peaks were observed at 90° intervals on the cubic (220) plane of the Si contained in substrate 11 during this φ scan. That is, four symmetrical diffraction peaks were observed in the Si contained in substrate 11 during this φ scan. Furthermore, as... Figure 41 As shown in the graph above, four strong diffraction peaks were observed at 90° intervals on the cubic (220) plane of SiGe contained in semiconductor film 31 during this φ scan. That is, four symmetrical diffraction peaks were observed in SiGe contained in semiconductor film 31 during this φ scan. Furthermore, in comparison... Figure 41 The chart on the top and Figure 41 In the diagram below, the angles of the four strong diffraction peaks of the cubic (220) plane of SiGe contained in the semiconductor film 31 are close to any one of the angles of the four strong diffraction peaks of the cubic (220) plane of Si contained in the substrate 11.

[0391] Therefore, it can be determined that the SiGe contained in the semiconductor film 31 has a cubic crystal structure and is oriented at (100), and that the crystal axis of the SiGe contained in the semiconductor film 31 is also aligned in the in-plane direction along the main plane 11p of the substrate 11, i.e., epitaxial growth has been performed. Furthermore, it can be determined that the semiconductor film 31 is oriented such that the <100> direction along the main plane 11p of the semiconductor film 31 is aligned with the <100> direction along the main plane 11p of the Si contained in the substrate 11. Figure 41 As shown, the angle between the <100> direction along the main surface 11p of the semiconductor film 31 and the <100> direction along the main surface 11p of the Si contained in the substrate 11 is 1.65°.

[0392] Furthermore, although not illustrated, a φ scan was performed on the cubic (220) plane (2θ = 50°) of the SHZO contained in the buffer film 12. The results were the same as in Example 20. In this φ scan, the SHZO contained in the buffer film 12 was observed to exhibit four-fold symmetrical diffraction peaks. The angles of the four strong diffraction peaks of the cubic (220) plane of the SHZO contained in the buffer film 12 were close to any one of the angles of the four strong diffraction peaks of the cubic (220) plane of the Si contained in the substrate 11.

[0393] Therefore, it can be known that the SHZO contained in the buffer film 12 has a cubic crystal structure and is oriented at (100), and that the crystal axis of the SHZO contained in the buffer film 12 is also consistent in the in-plane direction along the principal plane 11p of the substrate 11, i.e., epitaxial growth has been performed. Furthermore, it can be known that the buffer film 12 is oriented in such a way that when represented as a pseudocubic crystal, it is oriented along the <100> direction of the principal plane 11p of the metal oxide in the manner of the <100> direction along the principal plane 11p of the Si contained in the substrate 11.

[0394] Although detailed descriptions are omitted, in the stacked structures of Embodiments 6 and 7, which replace the stacked structure of Embodiment 21, a semiconductor film 31 containing SiGe can also be formed on the buffer film 13, and the results are substantially the same as those of Embodiment 21.

[0395] (Example 22)

[0396] Next, except that the Si:Ge (atomic ratio, the same below) value when forming semiconductor film 31 by MBE method is 50:50 as the target value, the stacked structure of Example 22 was fabricated in the same way as in Example 21.

[0397] After the buffer film 12 is formed on the main surface 11p of the substrate 11 and before the semiconductor film 31 is formed, the diffraction pattern of the stacked structure is measured by X-ray diffraction with the diffraction plane parallel to the main surface 11p in XRD measurement using the θ-2θ method. Although the results are not illustrated, they are similar to those obtained in the XRD method. Figure 35 The same result was obtained. That is, it can be known that the metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation.

[0398] Furthermore, after forming the semiconductor film 31, the diffraction pattern of the resulting stacked structure of Example 22 was measured using X-ray diffraction with the diffraction plane parallel to the principal plane 11p in an out-of-plane X-ray diffraction measurement. The measured diffraction pattern of the stacked structure of Example 22 is shown below. Figure 42 .

[0399] like Figure 42 As shown, in the diffraction pattern (out-of-plane measurement) of Example 22, strong diffraction peaks were observed on the cubic (200) plane of SHZO (SHZO c(200)), the cubic (400) plane of SHZO (SHZO c(400)), and the tetragonal (002) plane of SHZO (SHZO t(002)). In this case, it can be concluded that the metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation.

[0400] Furthermore, after forming the semiconductor film 31, the semiconductor film 31 was irradiated with incident X-rays. The resulting stacked structure of Example 22 was then measured using X-ray diffraction with the diffraction plane tilted at 90° relative to the principal plane 11p in an in-plane X-ray diffraction measurement employing the θ-2θ method. The diffraction pattern of the uppermost layer of the stacked structure of Example 22, measured with the diffraction plane tilted at 90° relative to the principal plane 11p, is shown below. Figure 43 The diffraction pattern of the stacked structure of Example 22, measured with the diffraction plane tilted at an angle of slightly less than 90° relative to the principal plane 11p, is shown below. Figure 44 .exist Figure 44 In this case, the incident X-rays irradiate the substrate 11.

[0401] like Figure 43 and Figure 44As shown, in the diffraction pattern (in-plane measurement) of Example 22, a strong diffraction peak (Si(220)) of the cubic (220) plane of SiGe was observed. Furthermore, Figure 43 The intensity of the diffraction peak (Si(220)) of the cubic (220) plane of SiGe is stronger than that of the other two. Figure 44 The intensity of the diffraction peak (Si(220)) of the cubic crystal (220) plane of SiGe. In this case, it can be known that the semiconductor film 31 contains SiGe.

[0402] After measuring Figure 43 and Figure 44 Following the diffraction pattern shown (in-plane measurement), a φ scan was performed on the cubic (220) plane (2θ = 47°) of SiGe contained in the semiconductor film 31, with the stacked structure arranged in a manner where the diffraction plane in the X-ray diffraction measurement was tilted at 90° relative to the principal plane 11p (in-plane measurement). Furthermore, with the substrate 11 irradiated by incident X-rays, a φ scan was performed on the cubic (220) plane (2θ = 47°) of Si contained in the substrate 11, with the tilt angle of the diffraction plane in the X-ray diffraction measurement slightly deviated from 90° relative to the principal plane 11p. The φ scans measured on the semiconductor film 31 and substrate 11 of the stacked structure of Example 22 are shown below. Figure 45 . Figure 45 The chart on the top shows the φ scan of semiconductor film 31. Figure 45 The chart below shows the φ scan of substrate 11.

[0403] like Figure 42 As shown, in this diffraction pattern (out-of-plane), only a strong peak was observed on the Si(400) plane for Si. Furthermore, as... Figure 45 As shown in the chart below, four strong diffraction peaks were observed at 90° intervals on the cubic (220) plane of the Si contained in substrate 11 during this φ scan. That is, four symmetrical diffraction peaks were observed in the Si contained in substrate 11 during this φ scan. Furthermore, as... Figure 45 As shown in the graph above, four strong diffraction peaks were observed at 90° intervals on the cubic (220) plane of SiGe contained in semiconductor film 31 during this φ scan. That is, four symmetrical diffraction peaks were observed in SiGe contained in semiconductor film 31 during this φ scan. Furthermore, in comparison... Figure 45 The chart on the top and Figure 45 In the diagram below, the angles of the four strong diffraction peaks of the cubic (220) plane of SiGe contained in the semiconductor film 31 are close to any one of the angles of the four strong diffraction peaks of the cubic (220) plane of Si contained in the substrate 11.

[0404] Therefore, it can be determined that the SiGe contained in the semiconductor film 31 has a cubic crystal structure and is oriented at (100), and that the crystal axis of the SiGe contained in the semiconductor film 31 is also aligned in the in-plane direction along the main plane 11p of the substrate 11, i.e., epitaxial growth has been performed. Furthermore, it can be determined that the semiconductor film 31 is oriented such that the <100> direction along the main plane 11p of the semiconductor film 31 is aligned with the <100> direction along the main plane 11p of the Si contained in the substrate 11. Figure 45 As shown, the angle between the <100> direction along the main surface 11p of the semiconductor film 31 and the <100> direction along the main surface 11p of the Si contained in the substrate 11 is 1.2°.

[0405] Furthermore, although not illustrated, a φ scan was performed on the cubic (220) plane (2θ = 47°) of the SHZO contained in the buffer film 12. The results were the same as in Example 21. In this φ scan, the SHZO contained in the buffer film 12 was observed to exhibit four symmetrical diffraction peaks. The angles of the four strong diffraction peaks of the cubic (220) plane of the SHZO contained in the buffer film 12 were close to any one of the angles of the four strong diffraction peaks of the cubic (220) plane of the Si contained in the substrate 11.

[0406] Therefore, it can be known that the SHZO contained in the buffer film 12 has a cubic crystal structure and is oriented at (100), and that the crystal axis of the SHZO contained in the buffer film 12 is also consistent in the in-plane direction along the principal plane 11p of the substrate 11, i.e., epitaxial growth has been performed. Furthermore, it can be known that the buffer film 12 is oriented in such a way that when represented as a pseudocubic crystal, it is oriented along the <100> direction of the principal plane 11p of the metal oxide in the manner of the <100> direction along the principal plane 11p of the Si contained in the substrate 11.

[0407] Although detailed descriptions are omitted, in the stacked structures of Embodiments 6 and 7, which replace the stacked structure of Embodiment 22, a semiconductor film 31 containing SiGe can also be formed on the buffer film 13, and the results are substantially the same as those of Embodiment 22.

[0408] Furthermore, based on the results of Examples 20 to 22, it can be seen that the angle between the <100> direction along the main surface 11p of the semiconductor film 31 and the <100> direction along the main surface 11p of the Si contained in the substrate 11 is more suitable to be 1.2 to 1.76°.

[0409] Furthermore, although detailed descriptions are omitted, in any of Examples 20 to 22, in the first metal oxide or metal oxide, the ratio of Hf:Zr:Si (atomic ratio, the same below) is other than 20:60:20, and y1 in the above composition formula (5) satisfies 0 < y1 ≤ 0.3, and x1 satisfies 0 ≤ x1 ≤ 1 - y1, the same results were obtained as in the examples where the ratio of Hf:Zr:Si is 20:60:20 (x1 in the above composition formula (5) is 0.60, and y1 is 0.20).

[0410] Furthermore, although detailed descriptions are omitted, in any of Examples 21 and 22, the same results were obtained for the embodiments in which the Si:Ge ratio (atomic ratio, the same below) was other than 75:25 and 50:50 in the semiconductor film 31.

[0411] [Postscript]

[0412] A portion of the content described in the above embodiments is described below.

[0413] [Postscript 1]

[0414] A laminated structure having a substrate and a first buffer film formed on the substrate,

[0415] The aforementioned substrate is composed of a Si substrate or an SOI substrate. The SOI substrate comprises: a substrate composed of a Si substrate, an insulating layer on the substrate, and an SOI layer composed of a Si film on the insulating layer.

[0416] The aforementioned first buffer film is composed of a first metal oxide, which comprises: one or more metal elements selected from Group 4 elements, and one or more metal elements selected from Nb, Ta, Si, rare earth elements, Al, and Group 2 elements.

[0417] When the first metal oxide is represented as a pseudocubic crystal, it is oriented in (100), or has a monoclinic crystal structure and is oriented in (111), or has a monoclinic crystal structure and is oriented in (11-1).

[0418] [Postscript 2]

[0419] According to Appendix 1, the laminated structure has a second buffer film formed on the first buffer film.

[0420] The aforementioned second buffer film is composed of a second metal oxide, which contains one or more metal elements selected from Group 4 elements.

[0421] When the aforementioned second metal oxide is represented as a pseudocubic crystal, it exhibits a (100) orientation, or a monoclinic crystal structure with a (111) orientation, or a monoclinic crystal structure with a (11-1) orientation.

[0422] [Postscript 3]

[0423] According to the stacked structure described in Appendix 2, the Si substrate is composed of a Si(100) substrate, or the SOI layer is composed of a Si(100) film.

[0424] The aforementioned first metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation, or a monoclinic crystal structure with a (11-1) orientation, or an orthorhombic crystal structure with a (100) orientation.

[0425] The aforementioned second metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation, or a monoclinic crystal structure with a (11-1) orientation, or an orthorhombic crystal structure with a (100) orientation.

[0426] [Postscript 4]

[0427] According to the laminated structure described in Appendix 2, the Si substrate is composed of a Si(111) substrate, or the SOI layer is composed of a Si(111) film.

[0428] The aforementioned first metal oxide has a monoclinic crystal structure and is oriented (111), or has a monoclinic crystal structure and is oriented (11-1).

[0429] The aforementioned second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0430] Symbol Explanation

[0431] 10, 10a: Layered structure;

[0432] 11: Substrate;

[0433] 11a: Matrix;

[0434] 11b: Insulation layer;

[0435] 11c: SOI layer;

[0436] 11d: Opening;

[0437] 11p: Main page;

[0438] 12, 13: Buffer membrane;

[0439] 12a, 32: Gate insulating film;

[0440] 14: Piezoelectric film;

[0441] 15, 16: Conductive film;

[0442] 20, 20a, 20b: Electronic devices;

[0443] 31: Semiconductor film;

[0444] 31a: Channel layer;

[0445] 31b, 45: Source region;

[0446] 31c, 46: Drain region;

[0447] 31d, 33: Gate electrodes;

[0448] 34, 42: Component areas;

[0449] 35, 43: Isolation areas;

[0450] 36, 44: Component isolation insulating film.

Claims

1. A laminated structure having a substrate and a first buffer film formed on said substrate, The substrate is made of either a Si substrate or an SOI substrate. The SOI substrate comprises: a substrate made of a Si substrate, an insulating layer on the substrate, and an SOI layer made of a Si film on the insulating layer. The first buffer film is composed of a first metal oxide, which comprises: one or more metal elements selected from Group 4 elements, and one or more metal elements selected from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. The first metal oxide is (111) oriented when represented as a pseudocubic crystal.

2. The laminated structure according to claim 1, wherein a second buffer film is formed on the first buffer film. The second buffer film is composed of a second metal oxide, which contains one or more metal elements selected from Group 4 elements. The second metal oxide is (111) oriented when represented as a pseudocubic crystal.

3. The stacked structure according to claim 2, wherein, The first metal oxide has a cubic crystal structure with a (111) orientation, or has a tetragonal crystal structure with a (101) orientation. The second metal oxide has a tetragonal crystal structure and is (101) oriented.

4. The stacked structure according to claim 3, wherein, The first buffer film is composed of the first metal oxide represented by the following formula (1). In formula (1), M is selected from one or more elements chosen from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. The y1 satisfies 0 < y1 ≤ 0.

3. The x1 satisfies 0 ≤ x1 ≤ 1 - y1. The second buffer film is composed of the second metal oxide represented by the following formula (2). The x2 satisfies 0 ≤ x2 < 1 or x2 = 1.

5. The laminated structure according to claim 3, wherein a piezoelectric film is formed on the second buffer film. The piezoelectric film is composed of a metal nitride containing AlN. The AlN contained in the metal nitride is oriented in a (0001) pattern.

6. The laminated structure according to claim 2, wherein, The substrate is made of a Si(100) substrate, or the SOI layer is made of a Si(100) film.

7. The laminated structure according to claim 2, wherein, The substrate is made of Si(111) substrate, or the SOI layer is made of Si(111) film.

8. The laminated structure according to claim 5, wherein, The metal nitride comprises AlN with added Sc.

9. A laminated structure having a substrate and a first buffer film formed on said substrate, The substrate is made of either a Si substrate or an SOI substrate. The SOI substrate comprises: a substrate made of a Si substrate, an insulating layer on the substrate, and an SOI layer made of a Si film on the insulating layer. The first buffer film is composed of a first metal oxide, which comprises: one or more metal elements selected from Group 4 elements, and one or more metal elements selected from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. The first metal oxide is (100) oriented when represented as a pseudocubic crystal, or has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

10. The laminated structure according to claim 9, wherein a second buffer film is formed on the first buffer film. The second buffer film is composed of a second metal oxide, which contains one or more metal elements selected from Group 4 elements. The second metal oxide is oriented in (100) when represented as a pseudocubic crystal, or has a monoclinic crystal structure and is oriented in (111), or has a monoclinic crystal structure and is oriented in (11-1).

11. The laminated structure according to claim 10, wherein, The Si substrate is composed of a Si(100) substrate, or the SOI layer is composed of a Si(100) film. The first metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation, or a monoclinic crystal structure with a (11-1) orientation, or an orthorhombic crystal structure with a (100) orientation. The second metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation, or a monoclinic crystal structure with a (11-1) orientation, or an orthorhombic crystal structure with a (100) orientation.

12. The laminated structure according to claim 10, wherein, The Si substrate is composed of a Si(111) substrate, or the SOI layer is composed of a Si(111) film. The first metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented. The second metal oxide has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

13. The laminated structure according to claim 11 or 12, wherein, The first buffer membrane is composed of the first metal oxide represented by the following formula (3). In formula (3), M is selected from one or more elements chosen from Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. The y1 satisfies 0 < y1 ≤ 0.

3. The x1 satisfies 0 ≤ x1 ≤ 1 - y1. The second buffer film is composed of the second metal oxide represented by the following formula (4), The x2 satisfies 0 ≤ x2 < 1 or x2 = 1.

14. A laminated structure having a substrate, a buffer film formed on the substrate, and a semiconductor film formed on the buffer film. The substrate is made of either a Si substrate or an SOI substrate. The SOI substrate comprises: a substrate made of a Si substrate, an insulating layer on the substrate, and an SOI layer made of a Si film on the insulating layer. The buffer film is composed of a metal oxide comprising: one or more metal elements selected from Group 4 elements, and Si. The semiconductor film contains one or more elements selected from Si and Ge. The metal oxide, when represented as a pseudocubic crystal, exhibits a (100) orientation. The semiconductor film is (100) oriented when represented as a pseudocubic crystal.

15. The laminated structure according to claim 14, wherein, The substrate is composed of a Si(100) substrate comprising a main surface with Si(100) facets or the SOI substrate, wherein the SOI substrate comprises: the substrate, an insulating layer on the substrate, and an SOI layer comprising a Si(100) film on the insulating layer and comprising the main surface with Si(100) facets.

16. The laminated structure according to claim 15, wherein, The metal oxide has a cubic crystal structure with a (100) orientation, or a tetragonal crystal structure with a (001) orientation, or a monoclinic crystal structure with a (100) orientation.

17. The laminated structure according to claim 15, wherein, The buffer membrane is composed of the metal oxide represented by the following formula (5). The y1 satisfies 0 < y1 ≤ 0.

3. The x1 satisfies 0≤x1≤1-y1.

18. The laminated structure according to claim 15, wherein, The semiconductor film has a cubic crystal structure and is (100) oriented.

19. The laminated structure according to claim 15, wherein, The semiconductor film is grown epitaxially.

20. The laminated structure according to claim 15, wherein, The semiconductor film is oriented such that it is aligned along the <100> direction of the main surface of the semiconductor film in the same manner as the <100> direction of the main surface of the Si contained in the substrate.

21. The laminated structure according to claim 15, wherein, The buffer film is oriented such that, when represented as a pseudocubic crystal, it is aligned along the <100> direction of the main plane of the metal oxide in a manner that is also aligned along the <100> direction of the main plane of the Si contained in the substrate.

22. The stacked structure according to claim 15, wherein the angle between the <100> direction along the main surface of the semiconductor film and the <100> direction along the main surface of the Si contained in the substrate is 1.2 to 1.76°.

23. An electronic device having a laminated structure as described in any one of claims 1 to 22.

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