Laminated structure and electronic device

Abstract

A laminated structure (10) has a substrate (11) and a buffer film (12) formed on the substrate (11). The substrate (11) comprises an Si substrate, or an SOI substrate including a base body comprising an Si substrate, an insulating layer on the base body, and an SOI layer comprising an Si film on the insulating layer. The buffer film (12) comprises a first metal oxide including one or more metal elements selected from the group consisting of Group 4 elements, and one or more metal elements selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. The first metal oxide is (111)-oriented in a pseudo-cubic crystal display.

Description

Laminated structures and electronic devices

[0001] This invention relates to a laminated structure and an electronic device.

[0002] A crystalline film having a yttrium oxide-stabilized zirconium oxide (YSZ) film formed on a substrate is known. Japanese Patent Application Publication No. 2015-025166 (Patent Document 1) describes a crystalline film formed on a substrate having a (100) crystal plane, comprising a Zr film and a ZrO film formed on the Zr film. ２ Membrane and Y ２ O ３ A technique is disclosed comprising a laminated film or YSZ film formed by stacking films, wherein the full width at half maximum of the peak when the laminated film or YSZ film is evaluated by X-ray diffraction is 0.05° to 2.0°. In the technique described in Patent Document 1 above, the laminated film or YSZ film is an oriented film oriented to (100), a Pt film oriented to (100) is formed on the laminated film or YSZ film, and a PZT film oriented to (001) 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 equipped with the film structure are known. International Publication No. 2023 / 171108 (Patent Document 1) describes a substrate and a ZrO film formed on the substrate. ２ A film structure comprising a buffer film containing a silicon film and a piezoelectric film formed on the buffer film is disclosed, wherein the substrate is a Si substrate, or an SOI substrate comprising 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, and the polarization direction of the piezoelectric film is preferentially oriented perpendicular to the substrate.

[0004] In addition, the miniaturization and high integration of metal-oxide-semiconductor field-effect transistors (MOSFETs) as semiconductor devices are being advanced. Japanese Patent Application Laid-Open No. 2004-281594 (Patent Document 3) discloses a technology for a field-effect transistor including a semiconductor substrate, a first crystalline metal oxide layer formed on the semiconductor substrate and having a different lattice spacing from the semiconductor substrate, a strained semiconductor layer serving as a channel region formed on the first crystalline metal oxide layer, a gate insulating film and a gate electrode formed on the channel region, and source / drain regions disposed and formed on side portions of the channel region.

[0005] Japanese Patent Application Laid-Open No. 2005-005556 (Patent Document 4) discloses a technology for a semiconductor device having a gate electrode including a Si film and a SiGe film formed on a substrate via a gate insulating film, wherein an oxide film of a transition metal is provided on the uppermost layer of the gate insulating film, and the SiGe film is formed on the oxide film of the transition metal.

[0006] Japanese Patent Application Laid-Open No. 2015-025166 International Publication No. 2023 / 171108 Japanese Patent Application Laid-Open No. 2004-281594 Japanese Patent Application Laid-Open No. 2005-005556

[0007] Edited by The Chemical Society of Japan, "Chemical Handbook Basic Edition", Revised 5th Edition, Maruzen Publishing Co., Ltd., February 2004, p. II-291

[0008] In the technology described in Patent Document 1 above, in a crystal film formed on a Si substrate having a (100) crystal plane, a Zr film, a ZrO ２ film and a Y ２ O ３ film, or a YSZ film, are provided. However, it is impossible to orient a ZrO ２ film in the (111) direction on a Si substrate having a (100) crystal plane, and it has been difficult to orient a piezoelectric film or a dielectric film made of AlN, etc. in the (0001) direction on the ZrO ２ film.

[0009] In the technology described in Patent Document 2 above, the film structure comprises a Si(111) substrate and a ZrO(111)-oriented ZrO(111) formed on the Si(111) substrate. ２ The system includes a buffer film containing ZrO, a Pt layer formed on the buffer film and oriented (111), and a piezoelectric film made of AlN formed on the Pt layer and oriented (0001). Here, AlN has a hexagonal crystal structure. However, on a Si substrate having a different plane orientation from that of the Si(111) substrate, for example, a Si(100) substrate, ZrO ２ When forming an AlN film or the like oriented (0001) via a film, ZrO ２ It was difficult to form a piezoelectric film, i.e., a dielectric film, etc., made of an AlN film that had the same quality as the AlN film formed via the film.

[0010] Furthermore, YSZ is ZrO ２ ni Y ２ O ３ Although the material has been added as a stabilizer, in the technique described in Patent Document 1, when a dielectric film or conductive film having a crystal structure such as cubic, tetragonal, or monoclinic is oriented to (100) or (111) in pseudocubic form on a Si substrate having a (100) or (111) crystal plane via a multilayer film or YSZ film, it is desirable to use a material that is more stabilized than conventional YSZ and allows for easier control of the orientation of the dielectric film. However, it has been difficult to use a material that is more stabilized than conventional YSZ and allows for easier control of the orientation of the dielectric film or conductive film.

[0011] In the technology described in Patent Document 3 above, La is used as a metal oxide on a Si substrate having a (001) plane orientation. ２ O ３ La is deposited and ２ O ３ After transforming the silicon into a crystalline single crystal, Si is epitaxially grown to form a channel layer, or a layered SiGe layer is formed on the Si substrate via a SiGe layer and an embedded oxide film. However, the crystallinity of the Si film or SiGe film formed on the silicon substrate via an oxide film was not sufficient.

[0012] Furthermore, in the technology described in Patent Document 4 above, the semiconductor device is HfO formed on a silicon substrate. ２ membrane or ZrO ２ The device comprises a gate insulating film made of a film, and a gate electrode made of a Si film and a SiGe film formed on the gate insulating film. Furthermore, when the gate electrode is made of a polycrystalline Si film or a polycrystalline SiGe film, compared to when the gate electrode is made of an amorphous Si film or an amorphous SiGe film, conductive impurities (e.g., boron) injected into the gate electrode in a subsequent process can be efficiently thermally diffused along the grain boundaries, reducing the thermal history in subsequent processes and improving electrical properties such as leakage current characteristics and long-term reliability of the gate insulating film. However, the crystallinity of the Si film or SiGe film formed on a silicon substrate via an oxide film was not sufficient.

[0013] The present invention aims to provide a laminated structure capable of improving the crystallinity of a dielectric film, conductive film, or semiconductor film formed on a Si substrate, and an electronic device equipped with the laminated structure. Specifically, the present invention aims to provide a laminated structure having a buffer film formed on a Si substrate, and an electronic device equipped with the laminated structure, in which, even when a dielectric film or conductive film having a hexagonal crystal structure, or a dielectric film or conductive film having a crystal structure such as cubic, tetragonal, or monoclinic is formed on the buffer film, the dielectric film or conductive film having a hexagonal crystal structure can be easily oriented to (0001) regardless of the plane orientation of the Si substrate, or the dielectric film or conductive film having a crystal structure such as cubic, tetragonal, or monoclinic can be easily oriented to (100) or (111) in pseudo-cubic representation, and an electronic device equipped with the laminated structure.

[0014] Alternatively, the present invention aims to provide a laminated structure having a semiconductor film formed on a Si substrate via a metal oxide film, and an electronic device equipped with the laminated structure, wherein the crystallinity of the Si film or SiGe film formed on the silicon substrate via an oxide film can be improved, and an electronic device equipped with the laminated structure.

[0015] As a result of diligent study, the present inventors have found that the above problems can be solved by the following configuration: [1] A laminated structure having a substrate and a first buffer film formed on the substrate, wherein the substrate is a Si substrate, or an SOI substrate comprising 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 made of a first metal oxide comprising one or more metal elements selected from the group consisting of Group 4 elements, and one or more metal elements selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements, and the first metal oxide is oriented (111) in pseudocubic crystal representation. [2] A laminated structure according to [1], wherein a second buffer film is formed on the first buffer film, the second buffer film is made of a second metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements, and the second metal oxide is (111) oriented in pseudocubic crystal representation. [3] A laminated structure according to [2], wherein the first metal oxide has a cubic crystal structure and is (111) oriented, or has a tetragonal crystal structure and is (101) oriented, and the second metal oxide has a tetragonal crystal structure and is (101) oriented. [4] A laminated structure according to [3], the first buffer film is made of the first metal oxide represented by the following composition formula (1): (Hf １－ｘ１－ｙ１ Zr ｘ１ M ｙ１ ) O ２－ｚ１ ... (1) (However, in composition formula (1), M is one or more selected from the group consisting of 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, and the second buffer film consists of the second metal oxide represented by the following composition formula (2): (Hf １－ｘ２ Zr ｘ２ ) O ２... (2) A laminated structure in which x2 satisfies 0 ≤ x2 < 1 or x2 = 1. [5] A laminated structure in which the laminated structure described in [3] has a piezoelectric film formed on the second buffer film, the piezoelectric film is made of a metal nitride containing AlN, and the AlN contained in the metal nitride is (0001) oriented. [6] A laminated structure in which the laminated structure described in any of [2] to [5] is made of a Si(100) substrate or the SOI layer is made of a Si(100) film. [7] A laminated structure in which the laminated structure described in any of [2] to [5] is made of a Si(111) substrate or the SOI layer is made of a Si(111) film. [8] A laminated structure in which the laminated structure described in [5] is made of a metal nitride containing Sc-doped AlN. [9] A laminated structure comprising a substrate and a first buffer film formed on the substrate, wherein the substrate is a Si substrate, or an SOI substrate comprising 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 made of a first metal oxide comprising one or more metal elements selected from the group consisting of Group 4 elements, and one or more metal elements selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements, the first metal oxide is (100) oriented in pseudocubic crystal representation, or has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, the laminated structure.

[10] The laminated structure according to [9], wherein a second buffer film is formed on the first buffer film, the second buffer film is made of a second metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements, and the second metal oxide is (100) oriented in pseudocubic representation, or has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[11] In the laminated structure described in

[10] , the Si substrate is made of a Si(100) substrate, or the SOI layer is made of a Si(100) film, the first metal oxide has a cubic crystal structure and is (100) oriented, or a tetragonal crystal structure and is (001) oriented, or a monoclinic crystal structure and is (100) oriented, or a monoclinic crystal structure and is (11-1) oriented, or an orthorhombic crystal structure and is (100) oriented, and the second metal oxide has a cubic crystal structure and is (100) oriented, or a tetragonal crystal structure and is (001) oriented, or a monoclinic crystal structure and is (100) oriented, or an orthorhombic crystal structure and is (100) oriented, in the laminated structure.

[12] A laminated structure according to

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

[13] A laminated structure according to

[11] or

[12] , wherein the first buffer film is made of the first metal oxide represented by the following composition formula (3), (Hf. １－ｘ１－ｙ１ Zr ｘ１ M ｙ１ ) O ２－ｚ１ ... (3) (However, in composition formula (3), M is one or more selected from the group consisting of 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, and the second buffer film consists of the second metal oxide represented by the following composition formula (4): (Hf １－ｘ２ Zr ｘ２ ) O ２... (4) A laminated structure in which 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, wherein the substrate is a Si substrate, or an SOI substrate including 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 made of one or more metal elements selected from the group consisting of Group 4 elements and a metal oxide containing Si, the semiconductor film contains one or more elements selected from the group consisting of Si and Ge, the metal oxide is oriented (100) in pseudocubic crystal representation, and the semiconductor film is oriented (100) in pseudocubic crystal representation.

[15] A laminated structure according to

[14] , wherein the substrate is made of a Si(100) substrate including a main surface made of a Si(100) plane, or a laminated structure comprising a substrate, an insulating layer on the substrate, and an SOI layer on the insulating layer consisting of a Si(100) film and including the main surface made of a Si(100) plane.

[16] A laminated structure according to

[15] , wherein 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.

[17] A laminated structure according to

[15] , wherein the buffer film is made of the metal oxide represented by the following composition formula (5): (Hf １－ｘ１－ｙ１ Zr ｘ１ Si ｙ１ ) O ２－ｚ１... (5) A laminated structure in which y1 satisfies 0 < y1 ≤ 0.3 and x1 satisfies 0 ≤ x1 ≤ 1 - y1.

[18] A laminated structure in which the semiconductor film has a cubic crystal structure and is (100) oriented.

[19] A laminated structure in which the semiconductor film is epitaxially grown.

[20] A laminated structure in which the semiconductor film is oriented such that the <100> direction along the main surface of the semiconductor film is aligned with the <100> direction along the main surface of the Si contained in the substrate.

[21] A laminated structure in which the buffer film is oriented such that the <100> direction along the main surface of the metal oxide in pseudocubic crystal representation is aligned with the <100> direction along the main surface of the Si contained in the substrate.

[22] A laminated structure according to

[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 comprising the laminated structure according to any one of [1] to

[22] .

[0016] The laminated structure of the present invention and the electronic device equipped with the laminated structure can improve the crystallinity of a dielectric film, conductive film, or semiconductor film formed on a Si substrate. Specifically, the laminated structure of the present invention and the electronic device equipped with the laminated structure include a laminated structure having a buffer film formed on a Si substrate, and an electronic device equipped with the laminated structure. Even when a dielectric film having a hexagonal crystal structure, or a dielectric film or conductive film having a crystal structure such as cubic, tetragonal, or monoclinic is formed on the buffer film, regardless of the plane orientation of the Si substrate, the dielectric film or conductive film having a hexagonal crystal structure can be easily oriented to (0001), or the dielectric film or conductive film having a crystal structure such as cubic, tetragonal, or monoclinic can be easily oriented to (100) or (111) in pseudo-cubic representation.

[0017] Alternatively, the laminated structure of the present invention and the electronic device equipped with the laminated structure are laminated structures having a semiconductor film formed on a Si substrate via a film made of a metal oxide, and the electronic device equipped with the laminated structure can improve the crystallinity of the Si film or SiGe film formed on a silicon substrate via a film made of an oxide.

[0018] This is a cross-sectional view showing an example of a laminated structure according to Embodiment 1. This is a cross-sectional view showing another an example of a modified laminated structure according to Embodiment 1. This is a cross-sectional view showing another example of a modified laminated structure according to Embodiment 1. This is a cross-sectional view of an electronic device according to Embodiment 2. This is a cross-sectional view showing an example of a laminated structure according to Embodiment 3. This is a cross-sectional view showing another example of a laminated structure according to Embodiment 3. This is a cross-sectional view showing an example of an electronic device according to Embodiment 4. This is a cross-sectional view showing another example of an electronic device according to Embodiment 4. This is a graph showing the diffraction pattern of a laminated structure according to Embodiment 1. This is a graph showing the diffraction pattern of a laminated structure according to Embodiment 1. This is a graph showing the diffraction pattern of a laminated structure according to Embodiment 2. This is a graph showing the diffraction pattern of a laminated structure according to Embodiment 3. This is a graph showing the φ scan of a laminated structure according to Embodiment 3. This is a graph showing the diffraction pattern of a laminated structure according to Embodiment 4. This is a graph showing the diffraction pattern of a laminated structure according to Embodiment 5. This is a graph showing the diffraction pattern of a laminated structure according to Embodiment 6. This is a graph showing the diffraction pattern of a laminated structure according to Embodiment 7. This is a graph showing the diffraction pattern of the laminated structure of Example 8. This is a graph showing the diffraction pattern of the laminated structure of Example 8. This is a graph showing the diffraction pattern of the laminated structure of Example 9. This is a graph showing the diffraction pattern of the laminated structure of Example 9. This is a graph showing the diffraction pattern of the laminated structure of Example 10. This is a graph showing the diffraction pattern of the laminated structure of Example 11. This is a graph showing the diffraction pattern of the laminated structure of Example 12. This is a graph showing the diffraction pattern of the laminated structure of Example 13. This is a graph showing the diffraction pattern of the laminated structure of Example 14. This is a graph showing the diffraction pattern of the laminated structure of Example 15. This is a graph showing the diffraction pattern of the laminated structure of Example 16. This is a graph showing the diffraction pattern of the laminated structure of Example 17. This is a graph showing the diffraction pattern of the laminated structure of Example 18. This is a graph showing the diffraction pattern of the laminated structure of Example 19. This is a graph showing the diffraction pattern of the laminated structure of Example 20. This is a graph showing the diffraction pattern of the laminated structure of Example 20. This is a graph showing the diffraction pattern of the laminated structure of Example 20.This is a graph showing the φ scan of the laminated structure of Example 20. This is a graph showing the diffraction pattern of the laminated structure of Example 21. This is a graph showing the diffraction pattern of the laminated structure of Example 21. This is a graph showing the φ scan of the laminated structure of Example 21. This is a graph showing the diffraction pattern of the laminated structure of Example 22. This is a graph showing the diffraction pattern of the laminated structure of Example 22. This is a graph showing the φ scan of the laminated structure of Example 22.

[0019] The embodiments of the present invention will be described below with reference to the drawings.

[0020] Furthermore, the disclosure is merely an example, and any modifications that a person skilled in the art could easily conceive while maintaining the spirit of the invention are naturally included within the scope of the present invention. In addition, the drawings may schematically represent the width, thickness, shape, etc. of each part in order to clarify the explanation, but these are merely examples and do not limit the interpretation of the present invention.

[0021] (Embodiment 1) <Laminated Structure> First, the laminated structure of Embodiment 1 will be described. Figure 1 is a cross-sectional view showing an example of the laminated structure of Embodiment 1. Figures 2 to 4 are cross-sectional views showing other examples of the laminated structure of Embodiment 1.

[0022] The laminated structure 10 shown in Figures 1 and 2 comprises 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.

[0023] In the example shown in Figure 1, the substrate 11 is made of a silicon (Si) (100) substrate including a main surface 11p made of a Si (100) surface. In the example shown in Figure 2, the substrate 11 is made of an SOI (Silicon On Insulator) substrate including a base body 11a made of a Si substrate, an insulating layer 11b on the base body 11a, and an SOI (Silicon On Insulator) layer 11c on the insulating layer 11b that is made of a Si (100) film and includes a main surface 11p made of a Si (100) surface.

[0024] In the example shown in Figure 1, the substrate 11 may be a Si substrate, and in the example shown in Figure 2, the substrate 11 may be an SOI substrate comprising a base body 11a made of a Si substrate, an insulating layer 11b on the base body 11a, and an SOI layer 11c made of a Si film on the insulating layer 11b. However, if the substrate 11 is made of a Si(100) substrate, the manufacturing cost of the laminated structure can be reduced compared to the case where the substrate 11 is not made of a Si(100) substrate. Also, if the SOI layer 11c is made of a Si(100) film, the manufacturing cost of the laminated structure can be reduced compared to the case where the SOI layer 11c is not made of a Si(100) film.

[0025] Alternatively, in the example shown in Figure 1, the substrate 11 may be made of a Si(111) substrate including a main surface 11p made of a Si(111) plane. When the substrate 11 is made of a Si(111) substrate, the Si(111) plane has threefold symmetry compared to when the substrate 11 is not made of a Si(111) substrate, for example, a Y with threefold symmetry ２ O ３ (111) planes are easily epitaxially grown on the Si(111) plane, etc. ２ O ３ The (111) orientation becomes easier. Similarly, the SOI layer 11c may be made of a Si(111) film. When the SOI layer 11c is made of a Si(111) film, the Si(111) plane has triple symmetry compared to when the SOI layer 11c is not made of a Si(111) film, so for example, a Y with triple symmetry ２ O ３ (111) planes are easily epitaxially grown on the Si(111) plane, etc. ２ O ３ (111) orientation becomes easier.

[0026] The buffer film 12 is made of a first metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements, and one or more metal elements selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. The buffer film 13 is made of a second metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements. The first metal oxide is oriented (111) in pseudocubic crystal representation, and the second metal oxide is oriented (111) in pseudocubic crystal representation.

[0027] In this specification, when a metal oxide is described as being (111) oriented in pseudocubic crystal representation, it means that the metal oxide has a cubic crystal structure at room temperature and is (111) oriented, or that even if it has a tetragonal or monoclinic crystal structure at room temperature, it undergoes a phase transition at high temperatures to have a cubic crystal structure and is (111) oriented (the same applies when it is (100) oriented in pseudocubic crystal representation).

[0028] In the technology described in Patent Document 1 above, a crystalline film formed on a Si substrate having a (100) crystal plane, comprising a Zr film and ZrO formed on the Zr film. ２ Membrane and Y ２ O ３ The invention comprises a laminated film or a YSZ film formed by stacking films. However, the invention provides a ZrO on a Si substrate having a crystal plane of (100). ２ The film could not be oriented (111), ZrO ２ It was difficult to orient a piezoelectric film made of AlN, i.e., a dielectric film, etc., in the (0001) position on the film.

[0029] In the technology described in Patent Document 2 above, the film structure comprises a Si(111) substrate and a ZrO(111)-oriented ZrO(111) formed on the Si(111) substrate. ２ The system includes a buffer film containing ZrO, a Pt layer formed on the buffer film and oriented (111), and a piezoelectric film made of AlN formed on the Pt layer and oriented (0001). Here, AlN has a hexagonal crystal structure. However, on a Si substrate having a different plane orientation from that of the Si(111) substrate, for example, a Si(100) substrate, ZrO ２ When forming an AlN film or the like oriented (0001) via a film, ZrO２ It was difficult to form a piezoelectric film, i.e., a dielectric film, etc., made of an AlN film that had the same quality as the AlN film formed via the film.

[0030] Furthermore, YSZ is ZrO ２ ni Y ２ O ３ Although the material has been added as a stabilizer, in the technique described in Patent Document 1, when a dielectric film or conductive film having a crystal structure such as cubic, tetragonal, or monoclinic is oriented to (100) or (111) in pseudocubic form on a Si substrate having a (100) or (111) crystal plane via a multilayer film or YSZ film, it is desirable to use a material that is more stabilized than conventional YSZ and allows for easier control of the orientation of the dielectric film. However, it has been difficult to use a material that is more stabilized than conventional YSZ and allows for easier control of the orientation of the dielectric film or conductive film.

[0031] On the other hand, the laminated structure of this embodiment 1 has buffer films 12 and 13 sequentially formed on a Si substrate or an SOI substrate. Buffer film 12 is made of a first metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements, and one or more metal elements selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. Buffer film 13 is made of a second metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements. The first metal oxide is oriented (111) in pseudocubic crystal representation, and the second metal oxide is oriented (111) in pseudocubic crystal representation.

[0032] In such cases, regardless of the plane orientation of the Si substrate, the buffer film 12 and the buffer film 13 can each be oriented to (111), so that the piezoelectric film made of AlN formed on the buffer film 13 can be oriented to (0001). Therefore, in a laminated structure having a buffer film formed on a Si substrate, and an electronic device equipped with the laminated structure, even when forming a piezoelectric film made of AlN on the buffer film, regardless of the plane orientation of the Si substrate, a piezoelectric film made of AlN with a certain quality can be oriented to (0001), and the polarization direction of the piezoelectric film can be aligned to a direction perpendicular to the main surface 11p. Furthermore, even when forming a dielectric film or conductive film having a hexagonal crystal structure, or a dielectric film or conductive film having a cubic, tetragonal, or monoclinic crystal structure, on a buffer film, the dielectric film or conductive film having a hexagonal crystal structure can be easily oriented to (0001), or the dielectric film or conductive film having a cubic, tetragonal, or monoclinic crystal structure can be easily oriented to (100) or (111) in pseudo-cubic representation.

[0033] According to this embodiment 1, a piezoelectric film 14 can be easily grown in a single orientation on a substrate 11 made of a Si substrate or an SOI substrate via a buffer film 12 made of a first metal oxide and a buffer film 13 made of a second metal oxide. This is thought to be due to a crystal growth mechanism in which, for example, the dynamic lattice matching effect due to the twinning martensitic transformation exhibited by the first and second metal oxides acts as a driving force, propulsion, and propulsion force when the piezoelectric film 14 grows in a single orientation. However, the invention is not necessarily bound by this theory.

[0034] Table 1 shows preferred examples of the first metal oxide. Table 1 shows preferred examples of the first metal oxide and the standard Gibbs free energy of formation (kJmol) for each first metal oxide. －１ The value of ) is shown, and represents the value described in Non-Patent Document 1.

[0035]

[0036] HfO ２ , ZrO２ Including the above, the standard Gibbs free energy of formation values ​​for each of the first metal oxides shown in Table 1 are SiO ２ It is lower than the standard Gibbs free energy of formation. In such cases, the metal elements contained in each first metal oxide are SiO on the Si substrate. ２ By reducing the first metal oxide and then oxidizing it itself, each first metal oxide can be directly grown on the Si substrate.

[0037] In this embodiment, the laminated structure 10 does not necessarily have a buffer film 13. Even in this case, the first metal oxide contained in the buffer film 12 is oriented (111) in a pseudocubic crystal representation, thereby causing the piezoelectric film made of AlN formed on the buffer film 12 to be oriented (0001).

[0038] However, if the laminated structure 10 has a buffer film 13, the types of metal elements contained in the first metal oxide and the second metal oxide can be different between the first metal oxide contained in the buffer film 12 and the second metal oxide contained in the buffer film 13. For example, a first metal oxide that is less prone to martensitic transformation but has high self-orientation can be used as the buffer film 12, and a second metal oxide that is not highly self-orientation but readily undergoes martensitic transformation can be used as the buffer film 13. As a result, the entire buffer film consisting of the buffer film 12 and the buffer film 13 can be used to form a piezoelectric film 14 on the substrate 11 with controlled orientation and few defects, with good yield.

[0039] Furthermore, in the laminated structure 10 of this embodiment 1, similar to the laminated structure of embodiment 6 described later, 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 also contain Si. In such a case, similar to the laminated structure of embodiment 6 described later, the first metal oxide contained in the buffer film 12 is oriented (100) in a pseudocubic crystal representation, thereby allowing the semiconductor film made of Si or SiGe formed on the buffer film 12 to be oriented (100), similar to the laminated structure 10 of embodiment 3 described later.

[0040] Furthermore, the laminated structure 10 of this embodiment 1 does not necessarily have a buffer film 13, and 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 also contain Si. In such cases, similar to the laminated structure 10 of embodiment 3 described later, the first metal oxide contained in the buffer film 12 is oriented (100) in a pseudocubic crystal representation, thereby causing the semiconductor film made of Si or SiGe formed on the buffer film 12 to be oriented (100).

[0041] Preferably, the first metal oxide has a cubic crystal structure and is (111) oriented, or has a tetragonal crystal structure and is (101) oriented. When the first metal oxide has a tetragonal crystal structure, the lattice constant of the a axis is 1 / (2) greater than 1 times the lattice constant of the c axis. １／２ It is nearly twice as large. In such cases, the first metal oxide, which has a tetragonal crystal structure and is (101) oriented, will be (111) oriented in pseudocubic crystal representation.

[0042] Similarly, preferably, the second metal oxide has a tetragonal crystal structure and is (101) oriented. When the second metal oxide has a tetragonal crystal structure, the lattice constant of the a axis is 1 / (2) greater than 1 times the lattice constant of the c axis. １／２ It is nearly twice as large. In such cases, the second metal oxide, which has a tetragonal crystal structure and is (101) oriented, will be (111) oriented in pseudocubic representation.

[0043] Preferably, the buffer film 12 consists of a first metal oxide represented by the following compositional formula (1). (Hf １－ｘ１－ｙ１ Zr ｘ１ M ｙ１ ) O ２－ｚ１ ... (1) (However, in composition formula (1), M is one or more selected from the group consisting of Nb, Ta, Si, rare earth elements, Al, and group 2 elements.) In the above composition formula (1), y1 satisfies 0 < y1 ≤ 0.3, and x1 satisfies 0 ≤ x1 ≤ 1 - y1.

[0044] In the following, among the first metal oxides represented by the above compositional formula (1), the case in which M is yttrium (Y) and satisfies 0 < x1 < 1 and 0 < y ≤ 0.3 may be referred to as YHZO.

[0045] Preferably, the buffer film 13 consists of a second metal oxide represented by the following compositional formula (2). (Hf １－ｘ２ Zr ｘ２ ) O ２ ... (2) In the above composition formula (2), x² satisfies either 0 ≤ x² < 1 or x² = 1.

[0046] In the following, among the second metal oxides represented by the above compositional formula (2), those satisfying 0 < x² < 1 may be referred to as HZO.

[0047] In such a case (provided that 0 < x1 ≤ 1 - y1 and 0 < x2 < 1 are satisfied), both the first and second metal oxides are HfO ２ Although some or all of the Hf is replaced with at least Zr, 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, and it is possible to prevent or suppress fluctuations in its crystal structure depending on the temperature conditions when the buffer film 12 is formed.

[0048] Preferably, the buffer film 13 is made of a second metal oxide containing Hf and one or more metal elements selected from the group consisting of Group 4 elements other than Hf, and x2 satisfies 0 ≤ x2 < 1. This makes it possible to improve the dynamic lattice matching effect due to twinning martensitic transformation.

[0049] The laminated structure 10 shown in Figures 3 and 4 has a piezoelectric film 14 formed on a buffer film 13. The piezoelectric film 14 is made of a metal nitride containing aluminum nitride (AlN), and the AlN contained in the metal nitride is (0001) oriented. If the laminated structure 10 does not have a buffer film 13, the laminated structure 10 has a piezoelectric film 14 directly formed on a buffer film 12.

[0050] As described above, in the laminated structure 10 of this embodiment 1, regardless of the plane orientation of the Si substrate, the buffer film 12 and the buffer film 13 can each be oriented to (111), so that the piezoelectric film 14 made of AlN formed on the buffer film 13 can be oriented to (0001), and the polarization direction of the piezoelectric film 14 can be aligned to a direction perpendicular to the main surface 11p.

[0051] Preferably, the metal nitride contains AlN with added Sc. When Sc is added to the AlN contained in the metal nitride, the piezoelectric properties of the piezoelectric film 14 can be improved compared to when Sc is not added to the AlN contained in the metal nitride.

[0052] Furthermore, the piezoelectric film 14 may be made of a metal nitride containing gallium nitride (GaN) instead of AlN, or lithium niobate (LiNbO ３ ) or tantalum niobate (LiTaO ３ A metal oxide containing ) can be used. Preferably, GaN, LiNbO ３ , LiTaO ３ It is oriented (0001).

[0053] <Modified Forms of the Laminated Structure> Next, modified forms of the laminated structure of Embodiment 1 will be described. The laminated structure of this modified form differs from the laminated structure of Embodiment 1 in that the first metal oxide is (100) oriented in pseudocubic crystal representation, has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented. Figure 5 is a cross-sectional view showing an example of the laminated structure of the modified form of Embodiment 1. Figure 6 is a cross-sectional view showing another example of the laminated structure of the modified form of Embodiment 1.

[0054] The laminated structure 10a shown in Figures 5 and 6, like the laminated structure 10 shown in Figures 1 and 2, includes 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.

[0055] In the example shown in Figure 5, similar to the example shown in Figure 1, the substrate 11 is made of a silicon (Si) (100) substrate including a main surface 11p made of a Si (100) surface. In the example shown in Figure 6, similar to the example shown in Figure 2, the substrate 11 is made of an SOI substrate including a base body 11a made of a Si substrate, an insulating layer 11b on the base body 11a, and an SOI layer 11c on the insulating layer 11b that is made of a Si (100) film and includes a main surface 11p made of a Si (100) surface.

[0056] In the example shown in Figure 5, the substrate 11 may be any Si substrate, and in the example shown in Figure 6, the substrate 11 may be any SOI substrate comprising a base body 11a made of a Si substrate, an insulating layer 11b on the base body 11a, and an SOI layer 11c made of a Si film on the insulating layer 11b. However, if the substrate 11 is made of a Si(100) substrate, the manufacturing cost of the laminated structure can be reduced compared to the case where the substrate 11 is not made of a Si(100) substrate. Also, if the SOI layer 11c is made of a Si(100) film, the manufacturing cost of the laminated structure can be reduced compared to the case where the SOI layer 11c is not made of a Si(100) film.

[0057] Alternatively, in the example shown in Figure 5, the substrate 11 may be made of a Si(111) substrate including a main surface 11p made of a Si(111) plane. When the substrate 11 is made of a Si(111) substrate, the Si(111) plane has threefold symmetry compared to when the substrate 11 is not made of a Si(111) substrate, so for example, a Y with threefold symmetry ２ O ３ (111) planes are easily epitaxially grown on the Si(111) plane, etc. ２ O ３ The (111) orientation becomes easier. Similarly, the SOI layer 11c may be made of a Si(111) film. When the SOI layer 11c is made of a Si(111) film, the Si(111) plane has triple symmetry compared to when the SOI layer 11c is not made of a Si(111) film, so for example, a Y with triple symmetry ２ O ３ (111) planes are easily epitaxially grown on the Si(111) plane, etc. ２ O ３ (111) orientation becomes easier.

[0058] The buffer film 12 is made of a first metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements, and one or more metal elements selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements. The buffer film 13 is made of a second metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements. The first metal oxide is (100) oriented in pseudocubic crystal representation, or 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 is (100) oriented in pseudocubic crystal representation, or has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0059] For example, if the substrate 11 is made of a Si(100) substrate, or if the SOI layer 11c is made of a Si(100) film, the first metal oxide is oriented (100) in a pseudocubic crystal representation, and the second metal oxide is oriented (100) in a pseudocubic crystal representation, thereby enabling the buffer film 12 and buffer film 13 to be oriented (100) in a pseudocubic crystal representation. This makes it possible to easily align a dielectric film or conductive film formed on the buffer film 13, which has a crystalline structure such as cubic, tetragonal, or monoclinic, to (100) in a pseudocubic crystal representation.

[0060] On the other hand, if, for example, the substrate 11 is made of a Si(111) substrate, or the SOI layer 11c is made of a Si(111) film, the first metal oxide may have a monoclinic crystal structure and be (111) oriented, or have a monoclinic crystal structure and be (11-1) oriented, and the second metal oxide may have a monoclinic crystal structure and be (111) oriented, or have a monoclinic crystal structure and be (11-1) oriented, thereby allowing each of the buffer films 12 and 13 to be (111) oriented in pseudocubic form, and a dielectric film or conductive film formed on the buffer film 13 and having a crystal structure such as cubic, tetragonal, or monoclinic may be easily (111) oriented in pseudocubic form.

[0061] Therefore, in a laminated structure having a buffer film formed on a Si substrate, and in an electronic device equipped with the laminated structure, even when forming a dielectric film or conductive film having a hexagonal crystal structure, or a dielectric film or conductive film having a cubic, tetragonal, or monoclinic crystal structure on the buffer film, regardless of the plane orientation of the Si substrate, the dielectric film or conductive film having a hexagonal crystal structure can be easily oriented to (0001), or the dielectric film or conductive film having a cubic, tetragonal, or monoclinic crystal structure can be easily oriented to (100) or (111) in pseudo-cubic representation.

[0062] In other words, if the Si substrate is made of a Si(100) substrate, or the SOI layer is made of a Si(100) film, then the first metal oxide will have a cubic crystal structure and be (100) oriented, a tetragonal crystal structure and be (001) oriented, a monoclinic crystal structure and be (100) oriented, a monoclinic crystal structure and be (11-1) oriented, or an orthorhombic crystal structure and be (100) oriented. Similarly, the second metal oxide will have a cubic crystal structure and be (100) oriented, a tetragonal crystal structure and be (001) oriented, a monoclinic crystal structure and be (100) oriented, a monoclinic crystal structure and be (11-1) oriented, or an orthorhombic crystal structure and be (100) oriented.

[0063] Furthermore, if the Si substrate is made of a Si(111) substrate, or if the SOI layer is made of a Si(111) film, the first metal oxide will have a monoclinic crystal structure and be (111) oriented, or a monoclinic crystal structure and be (11-1) oriented. Furthermore, the second metal oxide will have a monoclinic crystal structure and be (111) oriented, or a monoclinic crystal structure and be (11-1) oriented.

[0064] Incidentally, the laminated structure 10a of this modification example may not have the buffer film 13. Even in such a case, when the first metal oxide contained in the buffer film 12 is (111) - oriented in the pseudo - cubic crystal representation, the piezoelectric film made of AlN formed on the buffer film 12 can be (0001) - oriented. Also, when forming a dielectric film or a conductor film having a hexagonal crystal structure on the buffer film, or a dielectric film or a conductor film having a crystal structure such as cubic, tetragonal or monoclinic, can the dielectric film or the conductor film having a hexagonal crystal structure be easily (0001) - oriented, or can the dielectric film or the conductor film having a crystal structure such as cubic, tetragonal or monoclinic be easily (100) - oriented or (111) - oriented in the pseudo - cubic crystal representation?

[0065] Also in this modification example, as in the first embodiment, preferably, the buffer film 12 is made of a first metal oxide represented by the following compositional formula (3). (Hf １－ｘ１－ｙ１ Zr ｘ１ M ｙ１ )O ２－ｚ１ ...(3) (However, in the compositional formula (3), M is one or more selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al and Group 2 elements.) In the above compositional formula (3), y1 satisfies 0 < y1 ≤ 0.3, and x1 satisfies 0 ≤ x + 1 ≤ 1 - y1. Incidentally, the above compositional formula (3) is the same compositional formula as the above compositional formula (1).

[0066] Also in this modification example, as in the first embodiment, preferably, the buffer film 13 is made of a second metal oxide represented by the following compositional formula (4). (Hf １－ｘ２ Zr ｘ２ )O ２ ...(4) In the above compositional formula (4), x2 satisfies 0 ≤ x2 < 1 or x2 = 1. Incidentally, the above compositional formula (4) is the same compositional formula as the above compositional formula (2).

[0067] In such a case (however, when 0 < x1 ≤ 1 - y1 and 0 < x2 < 1 are satisfied), both the first metal oxide and the second metal oxide are HfO ２Although some or all of the Hf is replaced with at least Zr, 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, and it is possible to prevent or suppress fluctuations in its crystal structure depending on the temperature conditions when the buffer film 12 is formed.

[0068] In this modified example, as in Embodiment 1, preferably the buffer film 13 is made of a second metal oxide containing Hf and one or more metal elements selected from the group consisting of Group 4 elements other than Hf, and x2 satisfies 0 ≤ x2 < 1. This makes it possible to improve the dynamic lattice matching effect due to twinning martensitic transformation.

[0069] (Embodiment 2) Next, the electronic device of Embodiment 2 will be described. The electronic device of Embodiment 2 is an electronic device consisting of an FBAR (Film Bulk Acoustic Resonator) equipped with the laminated structure of Embodiment 1 or a modified laminated structure of Embodiment 1.

[0070] Figure 7 is a cross-sectional view of the electronic device of Embodiment 2. The electronic device 20 shown in Figure 7 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.

[0071] Furthermore, as shown in Figure 7, if the laminated structure 10 has a substrate 11 as an SOI substrate, for example, by photolithography and etching using an alkaline etching solution, a part of the substrate 11a of the substrate 11 can be etched to form an opening 11d, as shown in Figure 7. Also, for example, by photolithography and etching, a part of the conductive film 16 as the upper electrode can be etched and patterned.

[0072] As a result, as shown in Figure 7, an electronic device made of an FBAR consisting of a laminated 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 can be formed within the opening 11d of the substrate 11a.

[0073] In the electronic device of this second embodiment, the AlN contained in the piezoelectric film 14 is (0001) oriented, which makes it possible to make the polarization direction of the AlN parallel to the electric field applied to the piezoelectric film 14, compared to the case where the AlN is not (0001) oriented, and thus improves the piezoelectric constant of the piezoelectric film 14.

[0074] Alternatively, a piezoelectric actuator consisting of a micro electro-mechanical system (MEMS) having multiple piezoelectric elements formed with high shape accuracy on a substrate 11a can be easily formed.

[0075] (Embodiment 3) Next, the laminated structure of Embodiment 3 will be described. The laminated structure of Embodiment 3 is made of ZrO contained in HZO ２ or HfO ２ is SiO ２ This embodiment differs from the laminated structure of Embodiment 1 in that it is stabilized by [a specific mechanism], has a buffer film 12 but does not have a buffer film 13, and has a semiconductor film 31 formed on the buffer film 12 instead of a piezoelectric film 14. Figure 8 is a cross-sectional view showing an example of the laminated structure of Embodiment 3. Figure 9 is a cross-sectional view showing another example of the laminated structure of Embodiment 3.

[0076] The laminated structure 10a shown in Figure 8 comprises 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.

[0077] In the example shown in FIG. 8, the substrate 11 is made of a Si(100) substrate including a main surface 11p composed of a Si(100) surface. In the example shown in FIG. 9, the substrate 11 is composed of a SOI substrate including a substrate body 11a made of a Si substrate, an insulating layer 11b on the substrate body 11a, and a SOI layer 11c made of a Si(100) film on the insulating layer 11b and including a main surface 11p composed of a Si(100) surface.

[0078] In the example shown in FIG. 8, the substrate 11 may be any Si substrate. In the example shown in FIG. 9, the substrate 11 may be any SOI substrate including a substrate body 11a made of a Si substrate, an insulating layer 11b on the substrate body 11a, and a 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 as compared with the case where the substrate 11 is not made of a Si(100) substrate. Further, when the SOI layer 11c is made of a Si(100) film, the manufacturing cost of the stacked structure can be reduced as compared with the case where the SOI layer 11c is not made of a Si(100) film.

[0079] The buffer film 12 is made of a metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements and Si. The semiconductor film 31 contains one or more elements selected from the group consisting of Si and Ge.The metal oxide is (100)-oriented in the pseudo-cubic crystal representation, and the semiconductor film 31 is (100)-oriented in the pseudo-cubic crystal representation.

[0080] In the present specification, the statement that the metal oxide is (100)-oriented in the pseudo-cubic crystal representation means that the metal oxide has a cubic crystal structure at room temperature and is (100)-oriented, or even if it has a tetragonal or monoclinic crystal structure at room temperature, it is (100)-oriented when it undergoes a phase transition to have a cubic crystal structure at high temperature.

[0081] In the technique described in the above Patent Document 3, La is used as a metal oxide on a Si substrate having a (001) plane orientation. ２ O ３ is vapor-deposited, and La ２ O ３After transforming the silicon into a crystalline single crystal, Si is epitaxially grown to form a channel layer, or a layered SiGe layer is formed on the Si substrate via a SiGe layer and an embedded oxide film. However, the crystallinity of the Si film or SiGe film formed on the silicon substrate via an oxide film was not sufficient.

[0082] Furthermore, in the technology described in Patent Document 4 above, the semiconductor device is HfO formed on a silicon substrate. ２ membrane or ZrO ２ The device comprises a gate insulating film made of a film, and a gate electrode made of a Si film and a SiGe film formed on the gate insulating film. Furthermore, when the gate electrode is made of a polycrystalline Si film or a polycrystalline SiGe film, compared to when the gate electrode is made of an amorphous Si film or an amorphous SiGe film, conductive impurities (e.g., boron) injected into the gate electrode in a subsequent process can be efficiently thermally diffused along the grain boundaries, reducing the thermal history in subsequent processes and improving electrical properties such as leakage current characteristics and long-term reliability of the gate insulating film. However, the crystallinity of the Si film or SiGe film formed on a silicon substrate via an oxide film was not sufficient.

[0083] On the other hand, the laminated structure of this third embodiment has a buffer film 12 and a semiconductor film 31 sequentially formed on a Si substrate or an SOI substrate. The buffer film 12 consists of one or more metal elements selected from the group consisting of Group 4 elements, and a metal oxide containing Si. The metal oxide is oriented (100) in pseudocubic crystal representation, and the semiconductor film 31 is oriented (100) in pseudocubic crystal representation.

[0084] In such cases, in a field-effect transistor where the semiconductor film 31 is the channel layer, the crystallinity of the Si film or SiGe film formed on a silicon substrate via a film made of an oxide can be improved. Therefore, Si, which will form the channel layer, can be epitaxially grown on the Si substrate via a buffer film 12 made of a metal oxide, and a SiGe layer can be formed on the Si substrate via a buffer film 12 made of a metal oxide.

[0085] Furthermore, in a laminated structure having a semiconductor film formed on a Si substrate via a gate insulating film, and in an electronic device equipped with the laminated 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 a subsequent process can be more efficiently thermally diffused along the grain boundaries, further reducing the thermal history in subsequent processes, and further improving electrical characteristics such as leakage current characteristics and long-term reliability of the gate insulating film.

[0086] According to this third embodiment, a semiconductor film 31 can be easily grown in a single orientation on a substrate 11 made of a Si substrate via a buffer film 12 made of a metal oxide. This is thought to be due to a crystal growth mechanism in which, for example, the dynamic lattice matching effect due to the twinning martensitic transformation exhibited by the metal oxide acts as a driving force, propulsion, and driving force when the semiconductor film 31 grows in a single orientation. However, the invention is not necessarily bound by such a theory.

[0087] As explained using Table 1 above, HfO ２ , ZrO ２ The standard Gibbs free energy of formation for metal oxides containing SiO is ２ It is lower than the standard Gibbs free energy of formation. In such cases, the metallic elements contained in the metal oxide are SiO on the Si substrate. ２ By reducing the material and then oxidizing itself, metal oxides can be grown directly on a Si substrate.

[0088] Preferably, 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. In such cases, a Si film or SiGe film having a cubic crystal structure and being (100) oriented can be epitaxially grown on the buffer film 12.

[0089] Preferably, the buffer film 12 consists of a metal oxide represented by the following compositional formula (5). (Hf １－ｘ１－ｙ１ Zr ｘ１ Si ｙ１ ) O２－ｚ１ ... (5) In the above composition formula (5), y1 satisfies 0 < y1 ≤ 0.3, and x1 satisfies 0 ≤ x1 ≤ 1 - y1. In the following, among the metal oxides represented by the above composition formula (5), those that satisfy 0 < x1 < 1 may be referred to as SHZO.

[0090] In such a case (provided that 0 < x1 ≤ 1 - y1 and 0 < y1 ≤ 0.3 are satisfied), the metal oxide is HfO ２ Although some or all of the Hf is replaced with at least Zr, 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, and it is possible to prevent or suppress fluctuations in its crystal structure depending on the temperature conditions when the buffer film 12 is formed.

[0091] Preferably, the semiconductor film 31 has a cubic crystal structure and is (100) oriented. In such a case, for example, HfO is placed on the silicon substrate. ２ membrane or ZrO ２ A single-crystal Si film or a single-crystal SiGe film can be easily formed via the film, and electrical properties such as leakage current characteristics and long-term reliability of the gate insulating film can be easily improved.

[0092] Preferably, the semiconductor film 31 is epitaxially grown. In this case, compared to when the semiconductor film is not epitaxially grown, the semiconductor film 31 has a cubic crystal structure and is more easily oriented (100), making it easy to form a single crystal Si film or a single crystal SiGe film.

[0093] Preferably, the semiconductor film 31 is oriented such that the <100> direction along the main surface 11p of the semiconductor film 31 aligns with the <100> direction along the main surface 11p of the Si contained in the substrate 11. Even in this case, compared to the case where the <100> direction along the main surface 11p of the semiconductor film 31 does not align with the <100> direction along the main surface 11p of the Si contained in the substrate 11, the semiconductor film 31 has a cubic crystal structure and is more easily oriented to (100), making it easy to form a single crystal Si film or a single crystal SiGe film. In this specification, "the first direction aligns with the second direction" means that the angle between the first direction and the second direction is 10° or less.

[0094] Preferably, the buffer film 12 is oriented such that the <100> direction along the main surface 11p of the metal oxide in the pseudocubic crystal representation aligns with the <100> direction along the main surface 11p of the Si contained in the substrate 11. In this case as well, compared to the case where the <100> direction along the main surface 11p of the metal oxide in the pseudocubic crystal representation does not align with the <100> direction along the main surface 11p of the Si contained in the substrate 11, the semiconductor film 31 has a cubic crystal structure and is more easily oriented to (100), making it possible to easily form a single crystal Si film or a single crystal SiGe film.

[0095] 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, the angle between the grain boundary of the semiconductor film 31 and the grain boundary of the buffer film 12 is larger than when the angle is less than 1.2°, so that conductive impurities injected into the gate electrode in a later process do not easily enter the buffer film 12. Also, 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, a single crystal Si film or a single crystal SiGe film can be formed more easily than when the angle exceeds 1.76°.

[0096] (Embodiment 4) Next, the electronic device of Embodiment 4 will be described. The electronic device of Embodiment 4 is an electronic device consisting of a MOSFET equipped with the stacked structure of Embodiment 3.

[0097] Figure 10 is a cross-sectional view showing an example of the electronic device of Embodiment 4. Figure 11 is a cross-sectional view showing another example of the electronic device of Embodiment 4.

[0098] In the example shown in Figure 10, the electronic device 20a comprises a laminated structure 10a having a substrate 11, a buffer film 12, and a semiconductor film 31 formed on the buffer film 12. The buffer film 12 as an insulating layer is formed on the substrate 11, which is a silicon substrate, and 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 with a conductivity type different from that of the channel layer 31a. ２ A gate insulating film 32 made of an oxide such as is formed. A gate electrode 33 made of polysilicon or metal is formed on the gate insulating film 32. The laminated structure 10a, which has a substrate 11, a buffer film 12, and a semiconductor film 31, has an element region 34 on which a MOSFET is formed and an isolation region 35 that separates the element region 34, and an element isolation insulating film 36 is formed in the isolation region 35.

[0099] The electronic device 20a shown in Figure 10 also has a buffer film 12 and a semiconductor film 31 sequentially formed on a Si substrate or an SOI substrate, similar to the laminated structure 10a of Embodiment 3. The buffer film 12 consists of one or more metal elements selected from the group consisting of Group 4 elements, and a metal oxide containing Si. The semiconductor film 31 contains one or more elements selected from the group consisting of Si and Ge. The metal oxide is oriented (100) in pseudocubic crystal representation, and the semiconductor film 31 is oriented (100) in pseudocubic crystal representation.

[0100] In such cases, in a MOSFET with a semiconductor film 31 as the channel layer, the crystallinity of the Si film or SiGe film formed on a silicon substrate via a film made of an oxide can be improved. Therefore, the Si film that will become the channel layer can be epitaxially grown on the Si substrate via a buffer film 12 made of a metal oxide, or the SiGe film can be formed on the Si substrate via a buffer film 12 made of a metal oxide, thereby improving the crystallinity of the Si film or SiGe film and enabling the realization of a MOSFET with excellent mobility, for example.

[0101] On the other hand, in the example shown in Figure 11, the electronic device 20b comprises a laminated structure 10a having a substrate 11, a buffer film 12, and a semiconductor film 31 formed on the buffer film 12. The silicon substrate 11 has an element region 42 on which semiconductor elements such as transistors are formed, and a separation region 43 that separates the element region 42, and an element separation insulating film 44 is formed in the separation region 43. Although not shown in the figure, a well region is also formed within the substrate 11 of the element region 42.

[0102] 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, flanking a channel region (not shown) below the gate electrode 31d.

[0103] The electronic device 20b shown in Figure 11 also has a buffer film 12 and a semiconductor film 31 sequentially formed on a Si substrate or an SOI substrate, similar to the laminated structure 10a of Embodiment 3. The buffer film 12 consists of one or more metal elements selected from the group consisting of Group 4 elements, and a metal oxide containing Si. The semiconductor film 31 contains one or more elements selected from the group consisting of Si and Ge. The metal oxide is oriented (100) in pseudocubic crystal representation, and the semiconductor film 31 is oriented (100) in pseudocubic crystal representation.

[0104] In such cases, for example, HfO is placed on the silicon substrate. ２ membrane or ZrO ２A single-crystal Si film or a single-crystal SiGe film can be formed via the film. Therefore, 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 a subsequent process can be more efficiently thermally diffused along the grain boundaries, further reducing the thermal history in subsequent processes and further improving the electrical properties of the gate insulating film, such as leakage current characteristics and long-term reliability.

[0105] The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples.

[0106] (Example 1) [Formation of Laminated Structure] The laminated structure of Example 1 was fabricated. The laminated structure of Example 1 is the laminated structure described using Figure 3 above in Embodiment 1.

[0107] First, the crystal growth surface of the Si(111) substrate 11 (see Figure 3) was treated with reactive ion etching (RIE), and after heating in the presence of oxygen to form a thermal oxide film, a first metal oxide orientation film, serving as a buffer film 12 (see Figure 3), was formed on the Si substrate by a molecular beam epitaxy (MBE) method, which involved a thermal reaction between the metal (Hf, Zr, Y) of the deposition source and the oxygen in the oxide film on the Si substrate. The Hf:Zr:Y (atomic ratio, hereafter the same) values ​​were 22.5:67.5:10, which was the target value. Deposition source: Hf, Zr, Y Pressure: 2 × 10 －４ Pa thickness: 5 nm, Substrate temperature: 1000°C

[0108] Next, oxygen was introduced, the temperature was lowered, and the pressure was increased to deposit an oriented film of the second metal oxide as a buffer film 13 (see Figure 3) using the MBE method. The conditions for the MBE method during this film deposition were as follows: The Hf:Zr ratio was 25:75, which was the target value. Evaporation source: Hf, Zr Pressure: 2 × 10 －２ Pa Thickness: 95 nm Substrate temperature: 900°C

[0109] Next, a piezoelectric film 14 (see Figure 3) made of AlN was formed on the buffer film 13 (see Figure 3) by sputtering to create the laminated structure of Example 1. The conditions for forming this piezoelectric film 14 are as follows: Apparatus: RF sputtering apparatus Pressure: 1-2 Pa Target: Al Gas: Ar / N ２ Power: 2500-3500W (AC) Substrate temperature: 350-450℃ Thickness: 100nm

[0110] In this way, the laminated structure of Example 1 was fabricated by forming a piezoelectric film 14 on the buffer film 13 by sputtering.

[0111] [X-ray Diffraction Measurement] After forming buffer films 12 and 13 on the main surface 11p of the substrate 11, and before forming the piezoelectric film 14, the laminated structure was positioned so that the diffraction plane in the θ-2θ method X-ray diffraction (XRD) measurement was parallel to the main surface 11p, and the diffraction pattern of the laminated structure was measured by the said X-ray diffraction measurement. The diffraction pattern of the laminated structure of Example 1 measured is shown in Figure 12. The XRD measurement was performed using a Rigaku SmartLab X-ray diffractometer.

[0112] As shown in Figure 12, in the diffraction pattern, strong diffraction peaks were observed in the tetragonal (101) plane of YHZO (YHZO t(101)) and the tetragonal (202) plane (YHZO t(202)), or strong diffraction peaks were observed in 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 1 / (2) greater than 1 times the lattice constant of the c-axis. １／２It is nearly twice as much. In such cases, it was revealed that the YHZO contained in the first metal oxide, which has a tetragonal crystal structure and is (101) oriented, is (111) oriented in pseudocubic representation, and the HZO contained in the second metal oxide, which has a tetragonal crystal structure and is (101) oriented, is (111) oriented in pseudocubic representation. Furthermore, it was revealed that the YHZO contained in the first metal oxide has a tetragonal crystal structure and is (101) oriented, and the HZO contained in the second metal oxide has a tetragonal crystal structure and is (101) oriented.

[0113] Furthermore, after forming the piezoelectric film 14, the diffraction pattern of the laminated structure of Example 1 was measured by X-ray diffraction measurement using the θ-2θ method, with the laminated structure arranged so that the diffraction plane in the X-ray diffraction measurement of Example 1 was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 1 is shown in Figure 13.

[0114] As shown in Figure 13, a strong diffraction peak was observed in the (0002) plane of AlN in the diffraction pattern of Example 1. Therefore, it was revealed that in Example 1, the AlN contained in the piezoelectric film 14 has a hexagonal crystal structure and is (0001) oriented.

[0115] (Example 2) Next, a laminated structure of Example 2 was fabricated in the same manner as in Example 1, except that a Si(100) substrate was used instead of a Si(111) substrate as the substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13.

[0116] For the laminated structure of Example 2, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main plane 11p. The measured diffraction pattern of the laminated structure of Example 2 is shown in Figure 14. In Figure 14, the cubic (200) plane is indicated as "c200" and the monoclinic (200) plane is indicated as "m200" (the same applies to Figures 15, 17 to 27 described later, including the indication of 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").

[0117] As shown in Figure 14, strong diffraction peaks were observed in the diffraction pattern for the cubic (200) plane and the monoclinic (200) plane of YHZO, as well as strong diffraction peaks for the cubic (200) plane and the monoclinic (200) plane of HZO. Therefore, it was revealed that the YHZO contained in the first metal oxide is (100) oriented in pseudocubic form, and the HZO contained in the second metal oxide is (100) oriented in pseudocubic form. Furthermore, it was revealed that when the Si substrate is a Si(100) substrate or the SOI layer is a Si(100) film, 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.

[0118] (Example 3) Next, the laminated structure of Example 3 was fabricated in the same manner as in Example 1, except that the value of Hf:Zr:Y (atomic ratio, the same applies hereafter) was 20:60:20, which was the target value, a Si(100) substrate was used instead of a Si(111) substrate as the substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13.

[0119] For the laminated structure of Example 3, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 3 is shown in Figure 15.

[0120] As shown in Figure 15, strong diffraction peaks were observed in the diffraction pattern of the cubic (200) plane of YHZO and the cubic (200) plane of HZO. Therefore, it was revealed that the YHZO contained in the first metal oxide is (100) oriented in pseudocubic form, and the HZO contained in the second metal oxide is (100) oriented in pseudocubic form. Furthermore, it was revealed that when the Si substrate is a Si(100) substrate or the SOI layer is a Si(100) film, the first metal oxide has a cubic crystal structure and is (100) oriented, and the second metal oxide has a cubic crystal structure and is (100) oriented.

[0121] Furthermore, with the laminated structure positioned so that the diffraction plane in the X-ray diffraction measurement is tilted at 90° with respect to the main plane 11p (in-plane measurement), a φ scan was performed on the cubic (200) plane of YHZO and the cubic (200) plane of HZO (2θ = 35°) contained in the metal oxide. Figure 16 shows the φ scan measured for the laminated structure of Example 3.

[0122] As shown in Figure 16, in the φ scan, four strong diffraction peaks were observed at 90° intervals along the cubic (200) plane of YHZO and the cubic (200) plane of HZO. In other words, in the φ scan, diffraction peaks showing four-fold symmetry were observed for both YHZO and HZO. Therefore, it became clear that the crystal axes of YHZO and HZO contained in the first metal oxide and HZO contained in the second metal oxide are aligned in the in-plane direction along the main surface 11p of the substrate 11, i.e., that they are epitaxially grown.

[0123] (Example 4) Next, a laminated structure of Example 4 was fabricated in the same manner as in Example 1, except that a Si(100) substrate was used instead of a Si(111) substrate as the substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13.

[0124] For the laminated structure of Example 4, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 4 is shown in Figure 17.

[0125] As shown in Figure 17, strong diffraction peaks were observed in the diffraction pattern of the monoclinic (11-1) plane of YHZO and the monoclinic (11-1) plane of HZO. Therefore, it was revealed that the YHZO contained in the first metal oxide is (111) oriented in pseudocubic form, and the HZO contained in the second metal oxide is (111) oriented in pseudocubic form. Furthermore, it was revealed that when the Si substrate is a Si(100) substrate or the SOI layer is a Si(100) film, the first metal oxide has a monoclinic crystal structure and is (11-1) oriented, and the second metal oxide has a monoclinic crystal structure and is (11-1) oriented.

[0126] (Example 5) Next, a laminated structure of Example 5 was fabricated in the same manner as in Example 1, except that Al was used instead of Y as M (the values ​​of Hf:Zr:Al (atomic ratio, the same applies below) were the target values, but 20:60:20), and a piezoelectric film 14 was not formed on the buffer film 13. When Al was used instead of Y as M, the first metal oxide was Al ２ O ３ - Called HZO. Al ２ O ３ -HZO is the ZrO contained in HZO. ２ or HfO ２ Al ２ O ３ It has been stabilized by [this method].

[0127] For the laminated structure of Example 5, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 5 is shown in Figure 18.

[0128] As shown in Figure 18, in the diffraction pattern, Al ２ O ３ Strong diffraction peaks were observed in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO, as well as in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, Al contained in the first metal oxide was observed. ２ O ３ It was revealed that -HZO is (111) oriented in pseudocubic crystal representation, and that HZO contained in the second metal oxide is (111) oriented in pseudocubic crystal representation. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0129] (Example 6) Next, a laminated structure of Example 6 was fabricated in the same manner as in Example 1, except that Si was used instead of Y as M (the values ​​of Hf:Zr:Si (atomic ratio, the same applies below) were the target values, but 22.5:67.5:10), a Si(100) substrate was used instead of a Si(111) substrate as the substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13. When Si was used instead of Y as M, the first metal oxide was SiO ２ - Referred to as HZO. SiO ２ -HZO is the ZrO contained in HZO. ２ or HfO ２ is SiO ２ It has been stabilized by [this method].

[0130] For the laminated structure of Example 6, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 6 is shown in Figure 19.

[0131] As shown in Figure 19, in the diffraction pattern, SiO ２ Strong diffraction peaks were observed in the cubic (200) plane, monoclinic (200) plane, and orthorhombic (200) plane of HZO, as well as in the cubic (200) plane, monoclinic (200) plane, and orthorhombic (200) plane of HZO. Therefore, SiO contained in the first metal oxide was observed. ２ It was revealed that -HZO is (100) oriented in a pseudocubic crystal structure, and that HZO contained in the second metal oxide is (100) oriented in a pseudocubic crystal structure. Furthermore, it was revealed that when the Si substrate is made of a Si(100) substrate, or when the SOI layer is made of a Si(100) film, the first metal oxide has a cubic crystal structure and is (100) oriented, or a monoclinic crystal structure and is (100) oriented, or an orthorhombic crystal structure and is (100) oriented, and the second metal oxide has a cubic crystal structure and is (100) oriented, or a monoclinic crystal structure and is (100) oriented, or an orthorhombic crystal structure and is (100) oriented.

[0132] In the laminated structure of Example 6, SiO ２ - Because the Si contained in HZO is easily etched using, for example, an alkaline etching solution, the buffer film 12 can be easily removed and processed (the same applies to the laminated structure of Example 7 described later).

[0133] (Example 7) Next, the laminated structure of Example 7 was fabricated in the same manner as in Example 1, except that Si was used instead of Y as M (the Hf:Zr:Si values ​​were the target values, but 20:60:20), a Si(100) substrate was used instead of a Si(111) substrate as the substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13. In Example 7 as in Example 6, the first metal oxide was SiO ２ - It is called HZO.

[0134] For the laminated structure of Example 7, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 7 is shown in Figure 20.

[0135] As shown in Figure 20, in the diffraction pattern, SiO ２ Strong diffraction peaks were observed in the cubic (200) plane and the tetragonal (002) plane of HZO, as well as in the cubic (200) plane and the tetragonal (002) plane of HZO. Therefore, SiO contained in the first metal oxide ２ It was revealed that -HZO is (100) oriented in a pseudocubic crystal structure, and that HZO contained in the second metal oxide is (100) oriented in a pseudocubic crystal structure. Furthermore, it was revealed that when the Si substrate is a Si(100) substrate or the SOI layer is a Si(100) film, the first metal oxide has a cubic crystal structure and is (100) oriented, or a tetragonal crystal structure and is (001) oriented, and the second metal oxide has a cubic crystal structure and is (100) oriented, or a tetragonal crystal structure and is (001) oriented.

[0136] (Example 8) Next, a laminated structure of Example 8 was fabricated in the same manner as in Example 1, except that magnesium (Mg) was used instead of Y as M (the values ​​of Hf:Zr:Mg (atomic ratio, the same applies hereafter) were the target values, but 22.5:67.5:10), a Si(100) substrate was used instead of a Si(111) substrate as the substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13. In Example 8, the first metal oxide is referred to as MHZO. MHZO is ZrO contained in HZO ２ or HfO ２ This is stabilized by MgO.

[0137] For the laminated structure of Example 8, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 8 is shown in Figure 21.

[0138] As shown in Figure 21, strong diffraction peaks were observed in the diffraction pattern for the cubic (200) plane and the monoclinic (200) plane of MHZO, as well as strong diffraction peaks for the cubic (200) plane and the monoclinic (200) plane of HZO. Therefore, it was revealed that the MHZO contained in the first metal oxide is (100) oriented in pseudocubic form, and the HZO contained in the second metal oxide is (100) oriented in pseudocubic form. Furthermore, it was revealed that when the Si substrate is a Si(100) substrate or the SOI layer is a Si(100) film, 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.

[0139] In the laminated structure of Example 8, the inclusion of MgO in HZO can increase the Young's modulus of HZO by, for example, several times to about 10 times (the same applies to the laminated structure of Example 9, which will be described later).

[0140] In the laminated structure of Example 8, a conductive film made of Pt and a conductive film made of iron (Fe) were sequentially laminated on the buffer film 13. Then, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 8 is shown in Figure 22.

[0141] As shown in Figure 22, in the diffraction pattern, in addition to the MHZO and HZO diffraction peaks shown in Figure 21, strong diffraction peaks of the cubic (200) plane of Pt and the cubic (200) plane of Fe were observed. Therefore, it became clear that the conductive film made of Pt has a cubic crystal structure and is (100) oriented, and the conductive film made of Fe has a cubic crystal structure and is (100) oriented.

[0142] (Example 9) Next, a laminated structure of Example 9 was fabricated in the same manner as in Example 1, except that Mg was used instead of Y as M (the values ​​of Hf:Zr:Mg were the target values, but 22.5:67.5:10), and the piezoelectric film 14 was not formed on the buffer film 13. In Example 9, as in Example 8, the first metal oxide is referred to as MHZO.

[0143] For the laminated structure of Example 9, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 9 is shown in Figure 23.

[0144] As shown in Figure 23, strong diffraction peaks were observed in the diffraction pattern for the monoclinic (111) plane and the monoclinic (11-1) plane of MHZO, as well as strong diffraction peaks for the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, it was revealed that the MHZO contained in the first metal oxide is (111) oriented in pseudocubic form, and the HZO contained in the second metal oxide is (111) oriented in pseudocubic form. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0145] In the laminated structure of Example 9, a conductive film made of Pt and a conductive film made of iron (Fe) were sequentially laminated on the buffer film 13. Then, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 9 is shown in Figure 24.

[0146] As shown in Figure 24, in the diffraction pattern, in addition to the MHZO and HZO diffraction peaks shown in Figure 23, strong diffraction peaks were observed on the cubic (111) plane of Pt and the cubic (110) plane of Fe. Therefore, it was revealed that the conductive film made of Pt has a cubic crystal structure and is (111) oriented, and the conductive film made of Fe has a cubic crystal structure and is (110) oriented.

[0147] (Example 10) Next, a laminated structure of Example 10 was fabricated in the same manner as in Example 1, except that titanium (Ti) was used instead of Y as M (the value of Hf:Zr:Ti (atomic ratio, the same applies below) was the target value, but 22.5:67.5:10), a Si(100) substrate was used instead of a Si(111) substrate as the substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13. In Example 10, the first metal oxide was TiO ２ - Referred to as HZO. TiO ２ -HZO is the ZrO contained in HZO. ２ or HfO ２ ga TiO ２ It has been stabilized by [this method].

[0148] For the laminated structure of Example 10, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 10 is shown in Figure 25.

[0149] As shown in Figure 25, in the diffraction pattern, TiO ２ Strong diffraction peaks were observed in the cubic (200) plane and monoclinic (200) plane of HZO, as well as in the cubic (200) plane and monoclinic (200) plane of HZO. Therefore, TiO contained in the first metal oxide ２ It was revealed that -HZO is (100) oriented in a pseudocubic crystal structure, and that HZO contained in the second metal oxide is (100) oriented in a pseudocubic crystal structure. Furthermore, it was revealed that when the Si substrate is made of a Si(100) substrate, or when the SOI layer is made of a Si(100) film, 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.

[0150] (Example 11) Next, a laminated structure of Example 11 was fabricated in the same manner as in Example 1, except that lanthanum (La) was used instead of Y as M (the values ​​of Hf:Zr:La (atomic ratio, the same applies below) were the target values, but 20:60:20), and a piezoelectric film 14 was not formed on the buffer film 13. In Example 11, the first metal oxide was La ２ O ３ - Referred to as HZO. La ２ O ３ -HZO is the ZrO contained in HZO. ２ or HfO ２ La ２ O ３ It has been stabilized by [this method].

[0151] For the laminated structure of Example 11, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 11 is shown in Figure 26.

[0152] As shown in Figure 26, in the diffraction pattern, La ２ O ３ Strong diffraction peaks were observed in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO, as well as in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, La contained in the first metal oxide ２ O ３ It was revealed that -HZO is (111) oriented in pseudocubic crystal representation, and that HZO contained in the second metal oxide is (111) oriented in pseudocubic crystal representation. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0153] (Example 12) Next, a laminated structure of Example 12 was fabricated in the same manner as in Example 1, except that niobium (Nb) was used instead of Y as M (the values ​​of Hf:Zr:Nb (atomic ratio, the same applies below) were the target values, but 22.5:67.5:10), and a piezoelectric film 14 was not formed on the buffer film 13. In Example 12, the first metal oxide was Nb ２ O ５ - Referred to as HZO. Nb ２ O ５ -HZO is the ZrO contained in HZO. ２ or HfO ２ ga Nb ２ O ５ It has been stabilized by [this method].

[0154] For the laminated structure of Example 12, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 12 is shown in Figure 27.

[0155] As shown in Figure 27, in the diffraction pattern, Nb ２ O ５ Strong diffraction peaks were observed in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO, as well as in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, Nb contained in the first metal oxide ２ O ５ It was revealed that -HZO is (111) oriented in pseudocubic crystal representation, and that HZO contained in the second metal oxide is (111) oriented in pseudocubic crystal representation. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0156] (Example 13) Next, a laminated structure of Example 13 was fabricated in the same manner as in Example 1, except that the Hf:Zr:Y (atomic ratio, the same applies hereafter) values ​​were 22.5:67.5:10, which are the target values, and that no piezoelectric film 14 was formed on the buffer film 13, and a Si(111) substrate was used as the substrate 11.

[0157] For the laminated structure of Example 13, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main plane 11p. The measured diffraction pattern of the laminated structure of Example 13 is shown in Figure 28. In Figure 28, the monoclinic (11-1) plane is indicated as "m11-1" and the monoclinic (111) plane is indicated as "m111" (the same applies to Figures 29 to 34 described later, including the indication of the cubic (200) plane as "c200" and the tetragonal (002) plane as "t200").

[0158] As shown in Figure 28, strong diffraction peaks were observed in the diffraction pattern for the monoclinic (111) plane and the monoclinic (11-1) plane of YHZO, as well as strong diffraction peaks for the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, it was revealed that the YHZO contained in the first metal oxide is (111) oriented in pseudocubic form, and the HZO contained in the second metal oxide is (111) oriented in pseudocubic form. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0159] (Example 14) Next, a laminated structure of Example 14 was fabricated in the same manner as in Example 1, except that the value of Hf:Zr:Y (atomic ratio, the same applies hereafter) was 20:60:20, which was the target value, and that no piezoelectric film 14 was formed on the buffer film 13, and a Si(111) substrate was used as the substrate 11.

[0160] For the laminated structure of Example 14, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 14 is shown in Figure 29.

[0161] As shown in Figure 29, strong diffraction peaks were observed in the diffraction pattern for the monoclinic (111) plane and the monoclinic (11-1) plane of YHZO, as well as strong diffraction peaks for the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, it was revealed that the YHZO contained in the first metal oxide is (111) oriented in pseudocubic form, and the HZO contained in the second metal oxide is (111) oriented in pseudocubic form. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0162] (Example 15) Next, a laminated structure of Example 15 was fabricated in the same manner as in Example 1, except that Si was used instead of Y as M (the values ​​of Hf:Zr:Si (atomic ratio, the same applies below) were the target values, but 22.5:67.5:10), and a piezoelectric film 14 was not formed on the buffer film 13, and a Si(111) substrate was used as the substrate 11. When Si was used instead of Y as M, the first metal oxide was SiO ２ - Referred to as HZO. SiO ２ -HZO is the ZrO contained in HZO. ２ or HfO ２ is SiO ２ It has been stabilized by [this method].

[0163] For the laminated structure of Example 15, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 15 is shown in Figure 30.

[0164] As shown in Figure 30, in the diffraction pattern, SiO ２ Strong diffraction peaks were observed in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO, as well as in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, SiO contained in the first metal oxide ２ It was revealed that -HZO is (111) oriented in pseudocubic crystal representation, and that HZO contained in the second metal oxide is (111) oriented in pseudocubic crystal representation. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0165] As mentioned above, in the laminated structure of Example 15, SiO ２ - Because the Si contained in HZO is easily etched using, for example, an alkaline etching solution, the buffer film 12 can be easily removed and processed.

[0166] (Example 16) Next, the laminated structure of Example 16 was fabricated in the same manner as in Example 1, except that Ce was used instead of Y as M (the values ​​of Hf:Zr:Ce (atomic ratio, the same applies below) were the target values, but 22.5:67.5:10), and a piezoelectric film 14 was not formed on the buffer film 13, and a Si(111) substrate was used as the substrate 11. When Ce was used instead of Y as M, the first metal oxide was CeO ２ - Referred to as HZO. CEO ２ -HZO is the ZrO contained in HZO. ２ or HfO２ ga CEO ２ It has been stabilized by [this method].

[0167] For the laminated structure of Example 16, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 16 is shown in Figure 31.

[0168] As shown in Figure 31, in the diffraction pattern, CeO ２ Strong diffraction peaks were observed in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO, as well as in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, CeO contained in the first metal oxide ２ It was revealed that -HZO is (111) oriented in pseudocubic crystal representation, and that HZO contained in the second metal oxide is (111) oriented in pseudocubic crystal representation. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0169] (Example 17) Next, a laminated structure of Example 17 was fabricated in the same manner as in Example 1, except that Ti was used instead of Y as M (the values ​​of Hf:Zr:Ti (atomic ratio, the same applies below) were target values, but 20:60:20), and a piezoelectric film 14 was not formed on the buffer film 13, and a Si(111) substrate was used as the substrate 11. In Example 17, the first metal oxide was TiO ２ - Referred to as HZO. TiO ２ -HZO is the ZrO contained in HZO. ２ or HfO ２ ga TiO ２ It has been stabilized by [this method].

[0170] For the laminated structure of Example 17, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 17 is shown in Figure 32.

[0171] As shown in Figure 32, in the diffraction pattern, TiO ２ Strong diffraction peaks were observed in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO, as well as in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, TiO contained in the first metal oxide ２ It was revealed that -HZO is (111) oriented in pseudocubic crystal representation, and that HZO contained in the second metal oxide is (111) oriented in pseudocubic crystal representation. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0172] (Example 18) Next, a laminated structure of Example 18 was fabricated in the same manner as in Example 1, except that Ta was used instead of Y as M (the values ​​of Hf:Zr:Ta (atomic ratio, the same applies below) were the target values, but 22.5:67.5:10), and a piezoelectric film 14 was not formed on the buffer film 13, and a Si(111) substrate was used as the substrate 11. In Example 18, the first metal oxide was Ta ２ O ５ - Referred to as HZO. Ta ２ O ５ -HZO is the ZrO contained in HZO. ２ or HfO ２ ga Ta ２ O ５ It has been stabilized by [this method].

[0173] For the laminated structure of Example 18, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 18 is shown in Figure 33.

[0174] As shown in Figure 33, in the diffraction pattern, Ta ２ O ５ Strong diffraction peaks were observed in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO, as well as in the monoclinic (111) plane and the monoclinic (11-1) plane of HZO. Therefore, Ta contained in the first metal oxide ２ O ５ It was revealed that -HZO is (111) oriented in pseudocubic crystal representation, and that HZO contained in the second metal oxide is (111) oriented in pseudocubic crystal representation. Furthermore, it was revealed that when the Si substrate is made of a Si(111) substrate or the SOI layer is made 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, 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.

[0175] (Example 19) Next, a laminated structure of Example 19 was fabricated in the same manner as in Example 1, except that Ca was used instead of Y as M (the value of Hf:Zr:Ca (atomic ratio, the same applies below) was the target value, but 20:60:20), a Si(100) substrate was used instead of a Si(111) substrate as the substrate 11, and a piezoelectric film 14 was not formed on the buffer film 13. In Example 19, the first metal oxide is referred to as CaO-HZO. CaO-HZO is a compound of ZrO contained in HZO. ２ or HfO ２ This is stabilized by CaO.

[0176] For the laminated structure of Example 19, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement using the θ-2θ method, with the laminated structure positioned so that the diffraction plane in the XRD measurement was parallel to the main surface 11p. The measured diffraction pattern of the laminated structure of Example 19 is shown in Figure 34.

[0177] As shown in Figure 34, strong diffraction peaks were observed in the diffraction pattern of CaO-HZO, specifically in the cubic (200) plane and the tetragonal (002) plane. Therefore, it became clear that the YHZO contained in the first metal oxide is (100) oriented in pseudocubic form, and the HZO contained in the second metal oxide is (100) oriented in pseudocubic form. Furthermore, it became clear that when the Si substrate is a Si(100) substrate or the SOI layer is a Si(100) film, the first metal oxide has a cubic crystal structure and is (100) oriented, or a tetragonal crystal structure and is (001) oriented, and the second metal oxide has a cubic crystal structure and is (100) oriented, or a tetragonal crystal structure and is (001) oriented.

[0178] Although a detailed explanation will be omitted, in all of Examples 1 to 19, even when the ratio of Hf:Zr:M (atomic ratio, the same applies hereinafter) in the first metal oxide is a ratio other than 22.5:67.5:10 or 20:60:20, and y1 in the above composition formula (1) or (3) satisfies 0 < y1 ≤ 0.3 and x1 satisfies 0 ≤ x1 ≤ 1 - y1, the same results as in each example where the ratio of Hf:Zr:M is 22.5:67.5:10 (x1 in the above composition formula (1) or (3) is 0.675 and y1 is 0.10) or 20:60:20 (x1 in the above composition formula (1) or (3) is 0.60 and y1 is 0.20) were obtained.

[0179] Furthermore, although a detailed explanation will be omitted, in all of Examples 1 to 19, even when the ratio of Hf:Zr (atomic ratio, the same applies hereinafter) in the second metal oxide was a ratio other than 25:75, and x² in the above compositional formula (2) or (4) satisfied 0 ≤ x² < 1 or x² = 1, the same results as in each example where the ratio of Hf:Zr was 25:75 (x² in the above compositional formula (2) or (4) was 0.75) were obtained.

[0180] (Example 20) [Formation of Laminated Structure] Next, a laminated structure of Example 20 was fabricated in the same manner as in Example 1, except that Si was used instead of Y as M (the values ​​of Hf:Zr:Si (atomic ratio, the same applies below) were target values, but 20:60:20), a Si(100) substrate was used instead of a Si(111) substrate as the 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 a piezoelectric film 14. When Si is used instead of Y as M, the metal oxide is SiO ２ - Referred to as HZO or SHZO. SiO ２ -HZO or SHZO is a substance containing ZrO in HZO. ２ or HfO ２ is SiO ２ It has been stabilized by [this method].

[0181] First, the crystal growth surface of the Si(100) substrate 11 (see Figure 8) was treated with RIE, and after heating in the presence of oxygen to form a thermal oxide film, the metal oxide oriented film, which serves as the buffer film 12 (see Figure 8), was formed on the Si substrate by the MBE method, which involves a thermal reaction between the metal deposition source (Hf, Zr, Si) and the oxygen in the oxide film on the Si substrate. The Hf:Zr:Si (atomic ratio, the same applies below) was 20:60:20, which was the target value. Deposition source: Hf, Zr, Si Pressure: 2 × 10 －４ Pa thickness: 5 nm, Substrate temperature: 1000°C

[0182] Next, oxygen was introduced, the temperature was lowered, and the pressure was increased to deposit an oriented metal oxide film as buffer film 12 (see Figure 8) using the MBE method. The conditions for the MBE method during this film deposition were as follows: The Hf:Zr:Si (atomic ratio, the same applies below) values ​​were 20:60:20, which was the target value. Evaporation source: Hf, Zr, Si Pressure: 2 × 10 －２ Pa Thickness: 95 nm Substrate temperature: 900°C

[0183] Next, a semiconductor film 31 (see Figure 8) made of Si was formed on the buffer film 12 (see Figure 8) by the MBE method to create the laminated structure of Example 20. The conditions for forming this semiconductor film are as follows: Evaporation source: Si Pressure: 2 × 10 －４ Pa Thickness: 100 nm Substrate temperature: 700-900°C

[0184] In this way, the laminated structure of Example 20 was fabricated by forming a semiconductor film on the buffer film 13 using the MBE method.

[0185] [X-ray diffraction measurement] After forming a buffer film 12 on the main surface 11p of the substrate 11, and before forming the semiconductor film, the diffraction pattern of the laminated structure was measured by X-ray diffraction measurement with the laminated structure positioned so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The diffraction pattern of the laminated structure of Example 20 measured is shown in Figure 35.

[0186] As shown in Figure 35, strong diffraction peaks were observed in the diffraction pattern of the cubic (200) plane of SHZO (SHZO c(200)) and the cubic (400) plane of SHZO (SHZO c(400)), as well as strong diffraction peaks of the tetragonal (002) plane of SHZO (SHZO t(002)) and the tetragonal (004) plane of SHZO (SHZO t(004)). In such cases, it became clear that the metal oxide has a cubic crystal structure and is (100) oriented, or has a tetragonal crystal structure and is (001) oriented.

[0187] Furthermore, after forming the semiconductor film 31, the diffraction pattern of the laminated structure of Example 20 was measured by X-ray diffraction measurement using the θ-2θ method, with the laminated structure positioned so that the diffraction plane in the X-ray diffraction measurement of Example 20 was parallel to the main surface 11p (out-of-plane measurement). The measured diffraction pattern of the laminated structure of Example 20 is shown in Figure 36.

[0188] As shown in Figure 36, a strong diffraction peak (SHZO c(200)) of the cubic (200) plane of SHZO was observed in the diffraction pattern (out-of-plane measurement) of Example 20. In such cases, it is clear that the metal oxide has a cubic crystal structure and is (100) oriented. 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 is clear that the buffer film 12 underwent a martensitic transformation and its crystal structure changed upon the formation of the semiconductor film 31.

[0189] Furthermore, after forming the semiconductor film 31, the diffraction pattern of the uppermost layer of the laminated structure of Example 20 was measured by X-ray diffraction measurement using the θ-2θ method, with the laminated structure positioned such that the diffraction plane in the X-ray diffraction measurement of the obtained Example 20 was tilted at 90° with respect to the main surface 11p, so that the incident X-rays irradiated onto the semiconductor film 31 (in-plane measurement). The measured diffraction pattern of the laminated structure of Example 20 is shown in Figure 37.

[0190] As shown in Figure 37, a strong diffraction peak (Si(220)) was observed in the diffraction pattern (in-plane measurement) of Example 20, specifically in the cubic (220) plane of Si. In such cases, it became clear that the semiconductor film 31 contains Si.

[0191] After measuring the diffraction pattern shown in Figure 37 (in-plane measurement), a φ scan was then performed on the cubic (220) plane (2θ = 47°) of Si contained in the semiconductor film 31, with the stacked structure positioned so that the diffraction plane in the X-ray diffraction measurement was tilted at 90° with respect to the main 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 tilt angle of the diffraction plane in the X-ray diffraction measurement slightly shifted from 90° with respect to the main plane 11p, so that the incident X-rays irradiated onto the substrate 11. Figure 38 shows the φ scans measured for the semiconductor film 31 and substrate 11 of the stacked structure of Example 20. The upper graph in Figure 38 shows the φ scan of the semiconductor film 31, and the lower graph in Figure 38 shows the φ scan of the substrate 11.

[0192] As shown in Figure 36, in the diffraction pattern (out of plane), only a strong peak on the Si(400) plane was observed for Si. Also, as shown in the lower graph of Figure 38, in the φ scan, four strong diffraction peaks on the cubic (220) plane of Si contained in the substrate 11 were observed at 90° intervals. That is, in the φ scan, diffraction peaks showing four-fold symmetry were observed for the Si contained in the substrate 11. Also, as shown in the upper graph of Figure 38, in the φ scan, four strong diffraction peaks on the cubic (220) plane of Si contained in the semiconductor film 31 were observed at 90° intervals. That is, in the φ scan, diffraction peaks showing four-fold symmetry were observed for the Si contained in the semiconductor film 31. Furthermore, comparing the upper graph of Figure 38 with the lower graph of Figure 38, the angles of each of the four strong diffraction peaks on the cubic (220) plane of Si contained in the semiconductor film 31 were close to the angles of any of the four strong diffraction peaks on the cubic (220) plane of Si contained in the substrate 11.

[0193] Therefore, it was revealed that the Si contained in the semiconductor film 31 has a cubic crystal structure and is (100) oriented, and that the crystal axes of the Si contained in the semiconductor film 31 are aligned in the in-plane direction along the main surface 11p of the substrate 11, i.e., epitaxial growth has occurred. Furthermore, it was revealed 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. As shown in Figure 38, 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 was 1.76°.

[0194] Furthermore, although not shown in the diagram, a φ scan was performed on the cubic (220) plane (2θ = 50°) of SHZO contained in the buffer film 12, with the inclination angle of the diffraction plane with respect to the main plane 11p in the X-ray diffraction measurement slightly shifted from 90°, so that the incident X-rays irradiated the buffer film 12. As a result, in this φ scan, diffraction peaks showing four-fold symmetry of SHZO contained in the buffer film 12 were observed. In addition, in this φ scan, four strong diffraction peaks of the cubic (220) plane of SHZO contained in the buffer film 12 were observed at 90° intervals. That is, in this φ scan, diffraction peaks showing four-fold symmetry of SHZO contained in the buffer film 12 were observed. Moreover, the angles of each of the four strong diffraction peaks of the cubic (220) plane of SHZO contained in the buffer film 12 were close to the angles of any of the four strong diffraction peaks of the cubic (220) plane of Si contained in the substrate 11.

[0195] Therefore, it was revealed that the SHZO contained in the buffer film 12 has a cubic crystal structure and is (100) oriented, and that the crystal axes of the SHZO contained in the buffer film 12 are aligned in the in-plane direction along the main surface 11p of the substrate 11, i.e., epitaxial growth has occurred. Furthermore, it was revealed that the buffer film 12 is oriented such that the <100> direction along the main surface 11p of the metal oxide in the pseudocubic crystal representation is aligned with the <100> direction along the main surface 11p of the Si contained in the substrate 11.

[0196] Although a detailed explanation is omitted, instead of the laminated structure of Example 20, a semiconductor film 31 containing Si can be formed on the buffer film 13 in the laminated structures of Examples 6 and 7, and results substantially similar to those of Example 20 can be obtained.

[0197] (Example 21) Next, a laminated structure of Example 21 was fabricated in the same manner as in Example 20, except that a semiconductor film 31 made of SiGe was formed as the semiconductor film 31 (see Figure 8). The Si:Ge (atomic ratio, the same applies below) value when the semiconductor film 31 was formed by the MBE method was 75:25, which was the target value.

[0198] After forming a buffer film 12 on the main surface 11p of the substrate 11, and before forming the semiconductor film 31, the laminated structure was arranged so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The diffraction pattern of the laminated structure was measured by the said X-ray diffraction measurement, and although not shown in the figure, the same result as in Figure 35 was obtained. In other words, it became clear that the metal oxide has a cubic crystal structure and is (100) oriented, or has a tetragonal crystal structure and is (001) oriented.

[0199] Furthermore, after forming the semiconductor film 31, the diffraction pattern of the laminated structure of Example 21 was measured by X-ray diffraction measurement using the θ-2θ method, with the laminated structure positioned so that the diffraction plane in the X-ray diffraction measurement of Example 21 was parallel to the main surface 11p (out-of-plane measurement). The measured diffraction pattern of the laminated structure of Example 21 is shown in Figure 39.

[0200] As shown in Figure 39, in the diffraction pattern of Example 21 (out-of-plane measurement), 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 such cases, it became clear that the metal oxide has a cubic crystal structure and is (100) oriented, or has a tetragonal crystal structure and is (001) oriented.

[0201] Furthermore, after forming the semiconductor film 31, the diffraction pattern of the uppermost layer of the laminated structure of Example 21 was measured by X-ray diffraction measurement using the θ-2θ method, with the laminated structure positioned such that the diffraction plane in the X-ray diffraction measurement of Example 21 was tilted 90° with respect to the main surface 11p, so that the incident X-rays irradiated onto the semiconductor film 31 (in-plane measurement). The measured diffraction pattern of the laminated structure of Example 21 is shown in Figure 40.

[0202] As shown in Figure 40, a strong diffraction peak (SiGe(220)) of the cubic (220) plane of SiGe was observed in the diffraction pattern (in-plane measurement) of Example 21. In such cases, it became clear that the semiconductor film 31 contains SiGe.

[0203] After measuring the diffraction pattern shown in Figure 40 (in-plane measurement), a φ scan was then performed on the cubic (220) plane (2θ = 47°) of SiGe contained in the semiconductor film 31, with the stacked structure positioned so that the diffraction plane in the X-ray diffraction measurement was tilted at 90° with respect to the main surface 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 tilt angle of the diffraction plane in the X-ray diffraction measurement slightly shifted from 90° with respect to the main surface 11p, so that the incident X-rays irradiated onto the substrate 11. Figure 41 shows the φ scans measured for the semiconductor film 31 and substrate 11 of the stacked structure of Example 21. The upper graph in Figure 41 shows the φ scan of the semiconductor film 31, and the lower graph in Figure 41 shows the φ scan of the substrate 11.

[0204] As shown in Figure 39, in the diffraction pattern (out of plane), only a strong peak on the Si(400) plane was observed for Si. Furthermore, as shown in the lower graph of Figure 41, in the φ scan, four strong diffraction peaks on the cubic (220) plane of Si contained in the substrate 11 were observed at 90° intervals. That is, in the φ scan, diffraction peaks showing four-fold symmetry were observed for Si contained in the substrate 11. Furthermore, as shown in the upper graph of Figure 41, in the φ scan, four strong diffraction peaks on the cubic (220) plane of SiGe contained in the semiconductor film 31 were observed at 90° intervals. That is, in the φ scan, diffraction peaks showing four-fold symmetry were observed for SiGe contained in the semiconductor film 31. Furthermore, comparing the upper graph of Figure 41 with the lower graph of Figure 41, the angles of each of the four strong diffraction peaks of the cubic (220) plane of SiGe contained in the semiconductor film 31 were close to the angles of any of the four strong diffraction peaks of the cubic (220) plane of Si contained in the substrate 11.

[0205] Therefore, it was revealed that the SiGe contained in the semiconductor film 31 has a cubic crystal structure and is (100) oriented, and that the crystal axes of the SiGe contained in the semiconductor film 31 are aligned in the in-plane direction along the main surface 11p of the substrate 11, i.e., that it has grown epitaxially. Furthermore, it was revealed 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. As shown in Figure 41, 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 was 1.65°.

[0206] Furthermore, although not shown in the diagram, a φ scan was performed on the cubic (220) plane (2θ = 50°) of SHZO contained in the buffer film 12. As a result, similar to Example 20, in this φ scan, diffraction peaks showing four-fold symmetry were observed in the SHZO contained in the buffer film 12, and the angles of each of the four strong diffraction peaks of the cubic (220) plane of SHZO contained in the buffer film 12 were close to the angles of any of the four strong diffraction peaks of the cubic (220) plane of Si contained in the substrate 11.

[0207] Therefore, it was revealed that the SHZO contained in the buffer film 12 has a cubic crystal structure and is (100) oriented, and that the crystal axes of the SHZO contained in the buffer film 12 are aligned in the in-plane direction along the main surface 11p of the substrate 11, i.e., epitaxial growth has occurred. Furthermore, it was revealed that the buffer film 12 is oriented such that the <100> direction along the main surface 11p of the metal oxide in the pseudocubic crystal representation is aligned with the <100> direction along the main surface 11p of the Si contained in the substrate 11.

[0208] Although a detailed explanation is omitted, instead of the laminated structure of Example 21, a semiconductor film 31 containing SiGe can be formed on the buffer film 13 in the laminated structures of Examples 6 and 7, and results substantially similar to those of Example 21 can be obtained.

[0209] (Example 22) Next, a laminated structure of Example 22 was fabricated in the same manner as in Example 21, except that the Si:Ge (atomic ratio, the same applies hereafter) value when the semiconductor film 31 was formed by the MBE method was 50:50, which was the target value.

[0210] After forming a buffer film 12 on the main surface 11p of the substrate 11, and before forming the semiconductor film 31, the laminated structure was arranged so that the diffraction plane in the XRD measurement using the θ-2θ method was parallel to the main surface 11p. The diffraction pattern of the laminated structure was measured by the said X-ray diffraction measurement, and although not shown in the figure, the same result as in Figure 35 was obtained. In other words, it became clear that the metal oxide has a cubic crystal structure and is (100) oriented, or has a tetragonal crystal structure and is (001) oriented.

[0211] Furthermore, after forming the semiconductor film 31, the diffraction pattern of the laminated structure of Example 22 was measured by X-ray diffraction measurement using the θ-2θ method, with the laminated structure positioned so that the diffraction plane in the X-ray diffraction measurement of Example 22 was parallel to the main surface 11p (out-of-plane measurement). The measured diffraction pattern of the laminated structure of Example 22 is shown in Figure 42.

[0212] As shown in Figure 42, in the diffraction pattern of Example 22 (out-of-plane measurement), 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 such cases, it became clear that the metal oxide has a cubic crystal structure and is (100) oriented, or has a tetragonal crystal structure and is (001) oriented.

[0213] Furthermore, after forming the semiconductor film 31, the diffraction pattern of the uppermost layer of the laminated structure of Example 22 was measured by X-ray diffraction measurement using the θ-2θ method, with the laminated structure positioned such that the diffraction plane in the X-ray diffraction measurement of the obtained Example 22 was tilted at approximately 90° with respect to the main surface 11p, so that the incident X-rays irradiated onto the semiconductor film 31 (in-plane measurement). Figure 43 shows the diffraction pattern of the laminated structure of Example 22 measured with the diffraction plane tilted at 90° with respect to the main surface 11p, and Figure 44 shows the diffraction pattern of the laminated structure of Example 22 measured with the diffraction plane tilted at an angle slightly smaller than 90° with respect to the main surface 11p. In the case of Figure 44, the incident X-rays irradiate the substrate 11.

[0214] As shown in Figures 43 and 44, a strong diffraction peak (Si(220)) of the cubic (220) plane of SiGe was observed in the diffraction pattern (in-plane measurement) of Example 22. Furthermore, the intensity of the diffraction peak (Si(220)) of the cubic (220) plane of SiGe in Figure 43 was stronger than the intensity of the diffraction peak (Si(220)) of the cubic (220) plane of SiGe in Figure 44. In such cases, it became clear that the semiconductor film 31 contains SiGe.

[0215] After measuring the diffraction patterns (in-plane measurement) shown in Figures 43 and 44, a φ scan was performed on the cubic (220) plane (2θ = 47°) of SiGe contained in the semiconductor film 31, with the stacked structure positioned so that the diffraction plane in the X-ray diffraction measurement was tilted at 90° with respect to the main 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 tilt angle of the diffraction plane in the X-ray diffraction measurement slightly shifted from 90° with respect to the main plane 11p, so that the incident X-rays irradiated onto the substrate 11. Figure 45 shows the φ scans measured for the semiconductor film 31 and substrate 11 of the stacked structure of Example 22. The upper graph of Figure 45 shows the φ scan of the semiconductor film 31, and the lower graph of Figure 45 shows the φ scan of the substrate 11.

[0216] As shown in Figure 42, in the diffraction pattern (out of plane), only a strong peak on the Si(400) plane was observed for Si. Furthermore, as shown in the lower graph of Figure 45, in the φ scan, four strong diffraction peaks on the cubic (220) plane of Si contained in the substrate 11 were observed at 90° intervals. That is, in the φ scan, diffraction peaks showing four-fold symmetry were observed for the Si contained in the substrate 11. Furthermore, as shown in the upper graph of Figure 45, in the φ scan, four strong diffraction peaks on the cubic (220) plane of SiGe contained in the semiconductor film 31 were observed at 90° intervals. That is, in the φ scan, diffraction peaks showing four-fold symmetry were observed for the SiGe contained in the semiconductor film 31. Furthermore, comparing the upper graph of Figure 45 with the lower graph of Figure 45, the angles of each of the four strong diffraction peaks of the cubic (220) plane of SiGe contained in the semiconductor film 31 were close to the angles of any one of the four strong diffraction peaks of the cubic (220) plane of Si contained in the substrate 11.

[0217] Therefore, it was revealed that the SiGe contained in the semiconductor film 31 has a cubic crystal structure and is (100) oriented, and that the crystal axes of the SiGe contained in the semiconductor film 31 are aligned in the in-plane direction along the main surface 11p of the substrate 11, i.e., epitaxial growth has occurred. Furthermore, it was revealed 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. As shown in Figure 45, 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 was 1.2°.

[0218] Furthermore, although not shown in the diagram, a φ scan was performed on the cubic (220) plane (2θ = 47°) of SHZO contained in the buffer film 12. As a result, similar to Example 22, in this φ scan, diffraction peaks showing four-fold symmetry were observed in the SHZO contained in the buffer film 12, and the angles of each of the four strong diffraction peaks of the cubic (220) plane of SHZO contained in the buffer film 12 were close to the angles of any of the four strong diffraction peaks of the cubic (220) plane of Si contained in the substrate 11.

[0219] Therefore, it was revealed that the SHZO contained in the buffer film 12 has a cubic crystal structure and is (100) oriented, and that the crystal axes of the SHZO contained in the buffer film 12 are aligned in the in-plane direction along the main surface 11p of the substrate 11, i.e., epitaxial growth has occurred. Furthermore, it was revealed that the buffer film 12 is oriented such that the <100> direction along the main surface 11p of the metal oxide in the pseudocubic crystal representation is aligned with the <100> direction along the main surface 11p of the Si contained in the substrate 11.

[0220] Although a detailed explanation is omitted, instead of the laminated structure of Example 22, a semiconductor film 31 containing SiGe can be formed on the buffer film 13 in the laminated structures of Examples 6 and 7, and results substantially similar to those of Example 22 can be obtained.

[0221] Furthermore, from the results of Examples 20 to 22, it became clear that preferably, 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 to 1.76°.

[0222] Furthermore, although a detailed explanation will be omitted, in all of Examples 20 to 22, even when the ratio of Hf:Zr:Si (atomic ratio, the same applies hereinafter) in the first metal oxide or metal oxide is a ratio 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 as in each example 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) were obtained.

[0223] Furthermore, although a detailed explanation will be omitted, in both Example 21 and Example 22, even when the Si:Ge (atomic ratio, hereinafter the same) ratio in the semiconductor film 31 was a ratio other than 75:25 or 50:50, the same results as in the examples where the Si:Ge ratio was 75:25 or 50:50 were obtained.

[0224] Furthermore, some of the details described in the above embodiment are described below.

[0225] [Note 1] A laminated structure comprising a substrate and a first buffer film formed on the substrate, wherein the substrate is a Si substrate, or an SOI substrate comprising 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 made of a first metal oxide comprising one or more metal elements selected from the group consisting of Group 4 elements, and one or more metal elements selected from the group consisting of Nb, Ta, Si, rare earth elements, Al, and Group 2 elements, the first metal oxide is (100) oriented in pseudocubic crystal representation, or has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, the laminated structure.

[0226] [Note 2] The laminated structure described in Note 1, wherein a second buffer film is formed on the first buffer film, the second buffer film is made of a second metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements, and the second metal oxide is (100) oriented in pseudocubic crystal representation, or has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

[0227] [Note 3] In the laminated structure described in Note 2, the Si substrate is made of a Si(100) substrate, or the SOI layer is made of a Si(100) film, the first metal oxide has a cubic crystal structure and is (100) oriented, or a tetragonal crystal structure and is (001) oriented, or a monoclinic crystal structure and is (100) oriented, or a monoclinic crystal structure and is (11-1) oriented, or an orthorhombic crystal structure and is (100) oriented, and the second metal oxide has a cubic crystal structure and is (100) oriented, or a tetragonal crystal structure and is (001) oriented, or a monoclinic crystal structure and is (100) oriented, or an orthorhombic crystal structure and is (100) oriented, in the laminated structure.

[0228] [Note 4] A laminated structure as described in Note 2, wherein the Si substrate is made of a Si(111) substrate, or the SOI layer is made 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, 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.

[0229] 10, 10a Stacked structure 11 Substrate 11a Base 11b Insulating layer 11c SOI layer 11d Aperture 11p Main surface 12, 13 Buffer film 12a, 32 Gate insulating film 14 Piezoelectric film 15, 16 Conductive film 20, 20a, 20b Electronic device 31 Semiconductor film 31a Channel layer 31b, 45 Source region 31c, 46 Drain region 31d, 33 Gate electrode 34, 42 Element region 35, 43 Isolation region 36, 44 Element isolation insulating film

Claims

1. A laminated structure comprising a substrate and a first buffer film formed on the substrate, wherein the substrate is a Si substrate, or an SOI substrate comprising 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 made of a first metal oxide comprising one or more metal elements selected from the group consisting of Group 4 elements, and one or more metal elements selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements, and the first metal oxide is oriented (111) in pseudocubic crystal representation.

2. A laminated structure according to claim 1, wherein a second buffer film is formed on the first buffer film, the second buffer film is made of a second metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements, and the second metal oxide is (111) oriented in pseudocubic crystal representation.

3. A laminated structure according to claim 2, wherein the first metal oxide has a cubic crystal structure and is (111) oriented, or has a tetragonal crystal structure and is (101) oriented, and the second metal oxide has a tetragonal crystal structure and is (101) oriented.

4. In the laminated structure according to claim 3, the first buffer film is made of the first metal oxide represented by the following composition formula (1): (Hf １－ｘ１－ｙ１ Zr ｘ１ M ｙ１ ) O ２－ｚ１ ... (1) (However, in composition formula (1), M is one or more selected from the group consisting of 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, and the second buffer film consists of the second metal oxide represented by the following composition formula (2): (Hf １－ｘ２ Zr ｘ２ ) O ２ ... (2) The laminated structure in which x2 satisfies 0 ≤ x2 < 1 or x2 = 1.

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

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

8. The laminated structure according to claim 5, wherein the metal nitride includes AlN to which Sc has been added.

9. A laminated structure comprising a substrate and a first buffer film formed on the substrate, wherein the substrate is a Si substrate, or an SOI substrate comprising 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 made of a first metal oxide comprising one or more metal elements selected from the group consisting of Group 4 elements, and one or more metal elements selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements, the first metal oxide is (100) oriented in pseudocubic crystal representation, or has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented, the laminated structure.

10. A laminated structure according to claim 9, comprising a second buffer film formed on the first buffer film, wherein the second buffer film is made of a second metal oxide containing one or more metal elements selected from the group consisting of Group 4 elements, and the second metal oxide is (100) oriented in pseudocubic crystal representation, or has a monoclinic crystal structure and is (111) oriented, or has a monoclinic crystal structure and is (11-1) oriented.

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

12. A laminated structure according to claim 10, wherein the Si substrate is made of a Si(111) substrate, or the SOI layer is made 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, 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.

13. In the laminate structure according to claim 11 or 12, the first buffer film is made of the first metal oxide represented by the following composition formula (3): (Hf １－ｘ１－ｙ１ Zr ｘ１ M ｙ１ )O ２－ｚ１ ... (3) (However, in composition formula (3), M is one or more selected from the group consisting of Nb, Ta, Si, Ti, rare earth elements, Al, and Group 2 elements.) y1 satisfies 0 < y1 ≤ 0.3, x1 satisfies 0 ≤ x1 ≤ 1 - y1, the second buffer film is made of the second metal oxide represented by the following composition formula (4): (Hf １－ｘ２ Zr ｘ２ )O ２ ... (4) x2 satisfies 0 ≤ x2 < 1 or x2 = 1, laminate structure.

14. A laminated structure comprising a substrate, a buffer film formed on the substrate, and a semiconductor film formed on the buffer film, wherein the substrate is a Si substrate, or an SOI substrate comprising 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 made of one or more metal elements selected from the group consisting of Group 4 elements and a metal oxide containing Si, the semiconductor film contains one or more elements selected from the group consisting of Si and Ge, the metal oxide is oriented (100) in pseudocubic crystal representation, and the semiconductor film is oriented (100) in pseudocubic crystal representation.

15. A laminated structure according to claim 14, wherein the substrate is made of a Si(100) substrate including a main surface made of a Si(100) plane, or the SOI substrate comprising the base, the insulating layer on the base, and an SOI layer on the insulating layer that is made of a Si(100) film and includes the main surface made of a Si(100) plane.

16. A laminated structure according to claim 15, wherein 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.

17. In the laminated structure according to claim 15, the buffer film is made of the metal oxide represented by the following composition formula (5): (Hf １－ｘ１－ｙ１ Zr ｘ１ Si ｙ１ ) O ２－ｚ１ ... (5) A laminated structure in which y1 satisfies 0 < y1 ≤ 0.3 and x1 satisfies 0 ≤ x1 ≤ 1 - y1.

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

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

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

21. A laminated structure according to claim 15, wherein the buffer film is oriented such that the <100> direction along the main surface of the metal oxide in the pseudocubic crystal representation is aligned with the <100> direction along the main surface of the Si contained in the substrate.

22. A laminated 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 comprising a laminated structure according to any one of claims 1 to 12, or any one of claims 14 to 22.

Images