Piezoelectric film integrated device, method for manufacturing the same, and acoustic vibration sensor

Abstract

To improve the performance of a piezoelectric film integrated device by providing two or more types of monocrystalline piezoelectric films on the same substrate.SOLUTION: A piezoelectric film integrated device (100) includes: a substrate (33); an electrode (34) provided on the substrate (33); a first piezoelectric element that is provided on the electrode (34) and that includes a first monocrystalline piezoelectric film (25 or 15) and a first electrode film (26 or 16) superimposed on the first monocrystalline piezoelectric film; and a second piezoelectric element that is provided on the first piezoelectric element and that includes a second monocrystalline piezoelectric film (15 or 25) and a second electrode film (16 or 26) superimposed on the second monocrystalline piezoelectric film.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a piezoelectric film integrated device, a method for manufacturing the same, and an acoustic vibration sensor.

Background Art

[0002] Conventionally, a piezoelectric element in which two piezoelectric films are laminated via an adhesion layer has been disclosed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional device, when a plurality of piezoelectric films are stacked, a high-performance piezoelectric film integrated device cannot be obtained.

[0005] An object of the present disclosure is to provide a high-performance piezoelectric film integrated device in which two or more types of piezoelectric elements having single-crystal piezoelectric films are stacked, a method for manufacturing the same, and an acoustic vibration sensor having the piezoelectric film integrated device.

Means for Solving the Problems

[0006] The piezoelectric film integrated device of the present disclosure 、 includes a substrate, an electrode provided on the substrate, a first single-crystal piezoelectric film and a first electrode film overlapping the first single-crystal piezoelectric film, a first piezoelectric element provided on the electrode, a second single-crystal piezoelectric film having a crystal structure different from the crystal structure of the first single-crystal piezoelectric film, and a second electrode film overlapping the second single-crystal piezoelectric film, and a second piezoelectric element provided on the first piezoelectric element. Furthermore, at least one of the first single-crystal piezoelectric film and the second single-crystal piezoelectric film is an epitaxially grown film that is grown on a growth substrate different from the substrate. It is characterized by the above.

Effects of the Invention

[0007] According to this disclosure, the performance of piezoelectric film integrated devices and acoustic vibration sensors can be improved by stacking two or more piezoelectric elements having single-crystal piezoelectric films. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic side view showing the structure of the piezoelectric film integrated device according to Embodiment 1. [Figure 2] Figure 1 is a schematic top view showing the structure of the piezoelectric film integrated device. [Figure 3] Figure 2 is a cross-sectional view of the piezoelectric film integrated device cut along the line S3-S3. [Figure 4] Figure 1 is a schematic bottom view showing the structure of the piezoelectric film integrated device. [Figure 5] This is a schematic cross-sectional view showing the structure of an epitaxially grown film containing a single-crystal piezoelectric film, specifically a single-crystal PZT film. [Figure 6] Figure 5 shows the crystal structure of a single-crystal PZT film. [Figure 7] Figure 5 shows a schematic diagram of the crystal structure of the epitaxially grown film. [Figure 8] This is a schematic cross-sectional view showing the structure of an epitaxially grown film containing a single-crystal AlN film, which is a single-crystal piezoelectric film. [Figure 9] (A) is a schematic diagram showing the (111) plane of the single-crystal SRO film, single-crystal Pt, and single-crystal ZrO2 crystals in Figure 8, and (B) is a diagram showing the lattice constant of the single-crystal SRO crystal. [Figure 10] (A) is a schematic diagram showing the crystal structure of the single-crystal AlN film in Figure 8, and (B) is a diagram showing the lattice constants of the single-crystal AlN. [Figure 11] Figure 1 is a flowchart showing the manufacturing method of a piezoelectric film integrated device. [Figure 12] (A) and (B) are schematic cross-sectional and top views showing the electrode structure in step ST102 of Figure 11. [Figure 13](A) and (B) are top view and cross-sectional view schematically showing the structure of the first epitaxial growth film in step ST103 of FIG. 11. [Figure 14] (A) and (B) are top view and cross-sectional view schematically showing the structure of the first epitaxial growth film in step ST104 of FIG. 11. [Figure 15] It is a cross-sectional view schematically showing the holding process of the first epitaxial growth film in step ST109 of FIG. 11. [Figure 16] It is a cross-sectional view schematically showing the etching process of the sacrificial layer in step ST109 of FIG. 11. [Figure 17] (A) and (B) are top view and cross-sectional view schematically showing the structure of the second epitaxial growth film in step ST105 of FIG. 11. [Figure 18] (A) and (B) are top view and cross-sectional view schematically showing the structure of the second epitaxial growth film in step ST106 of FIG. 11. [Figure 19] It is a cross-sectional view schematically showing the holding process of the second epitaxial growth film in step ST107 of FIG. 11. [Figure 20] It is a cross-sectional view schematically showing the etching process of the sacrificial layer in step ST107 of FIG. 11. [Figure 21] It is a cross-sectional view schematically showing the attaching process of the first epitaxial growth film in step ST108 of FIG. 11. [Figure 22] It is a cross-sectional view schematically showing the attaching process of the second epitaxial growth film in step ST110 of FIG. 11. [Figure 23] It is a diagram showing the crystal c-axis of the single crystal PZT film which is the first single crystal piezoelectric film and the crystal c-axis of the single crystal AlN film which is the second single crystal piezoelectric film. [Figure 24] It is a diagram schematically showing the configuration of an acoustic vibration sensor using the semiconductor integrated device according to Embodiment 1. [Figure 25] It is a diagram showing the operating principle of the acoustic vibration sensor. [Figure 26]It is a side view schematically showing the structure of a piezoelectric film integrated device according to a modification of Embodiment 1. [Figure 27] It is a top view schematically showing the structure of the piezoelectric film integrated device of FIG. 26. [Figure 28] It is a cross-sectional view of the piezoelectric film integrated device of FIG. 27 cut along line S28-S28. [Figure 29] It is a bottom view schematically showing the structure of the piezoelectric film integrated device of FIG. 26. [Figure 30] It is a side view schematically showing the structure of a piezoelectric film integrated device according to Embodiment 2. [Figure 31] It is a top view schematically showing the structure of the piezoelectric film integrated device of FIG. 30. [Figure 32] It is a cross-sectional view of the piezoelectric film integrated device of FIG. 31 cut along line S32-S32. [Figure 33] It is a flowchart showing the manufacturing method of the piezoelectric film integrated device of FIG. 30. [Figure 34] It is a cross-sectional view schematically showing the structure of the PZT epitaxial growth film in step ST202 of FIG. 33. [Figure 35] It is a cross-sectional view schematically showing the structure of the PZT epitaxial growth film (individual piece) in step ST203 of FIG. 33. [Figure 36] It is a cross-sectional view schematically showing the structure of the PZT epitaxial growth film (individual piece) and the AlN epitaxial growth film (individual piece) in step ST207 of FIG. 33. [Figure 37] It is a side view schematically showing the structure of a piezoelectric film integrated device according to Embodiment 3. [Figure 38] It is a top view schematically showing the structure of the piezoelectric film integrated device of FIG. 37. [Figure 39] It is a cross-sectional view of the piezoelectric film integrated device of FIG. 38 cut along line S39-S39. [Figure 40] It is a flowchart showing the manufacturing method of the piezoelectric film integrated device of FIG. 37. [Figure 41] It is a cross-sectional view schematically showing the structure of the AlN epitaxial growth film in step ST302 of FIG. 40. [Figure 42] Figure 40 is a schematic cross-sectional view showing the structure of the AlN epitaxial growth film (individual piece) in step ST303. [Figure 43] Figure 40 is a schematic cross-sectional view showing the structures of the AlN epitaxial growth film (pieces) and the PZT epitaxial growth film (pieces) in step ST307. [Figure 44] This is a schematic cross-sectional view showing the structure of an epitaxially grown film containing a single-crystal PZT film. [Figure 45] This is a schematic cross-sectional view showing the structure of an epitaxially grown film containing a single-crystal AlN film. [Figure 46] This is a schematic cross-sectional view showing the structure of a piezoelectric film integrated device according to a modified example 1 of Embodiment 1. [Figure 47] Figure 46 is a schematic top view showing the structure of the piezoelectric film integrated device. [Modes for carrying out the invention]

[0009] The following describes a piezoelectric film integrated device, a method for manufacturing the same, and an acoustic vibration sensor according to an embodiment, with reference to the drawings. The following embodiment is merely an example, and various modifications are possible within the scope of this disclosure. In this application, a piezoelectric film integrated device is a device having two or more single-crystal piezoelectric films on the same substrate. In this application, an acoustic vibration sensor is a sensor that outputs an acoustic vibration wave and detects the state of an object to be detected (e.g., distance, shape, movement, etc.) by detecting the reflected wave of the acoustic vibration wave. An acoustic vibration sensor is also called an "ultrasonic sensor." Generally, and also in this application, an acoustic vibration wave consists of at least one of a sound wave and an ultrasonic wave. That is, an acoustic vibration wave consists of a sound wave, or an ultrasonic wave, or both a sound wave and an ultrasonic wave.

[0010] (1) Embodiment 1 《1-1》Structure of piezoelectric film integrated device 100 Figure 1 is a schematic side view showing the structure of the piezoelectric film integrated device 100 according to Embodiment 1. Figure 2 is a schematic top view showing the structure of the piezoelectric film integrated device 100. Figure 3 is a cross-sectional view of the piezoelectric film integrated device 100 in Figure 2, cut along the line S3-S3. Figure 4 is a schematic bottom view showing the structure of the piezoelectric film integrated device 100.

[0011] The piezoelectric film integrated device 100 includes an SOI substrate 33 as a substrate and a platinum (Pt) film 34 as an electrode provided on the SOI substrate 33. As shown in Figure 2, the Pt film 34 is connected to the connector 40 through a wiring layer formed on the SOI substrate 33. SOI stands for Silicon On Insulator. Furthermore, a drive circuit for driving the piezoelectric film integrated device 100 to generate acoustic vibration waves and a processing circuit for processing using the detected acoustic vibration wave signal may be formed within the SOI substrate 33.

[0012] The piezoelectric film integrated device 100 includes a first piezoelectric element (25, 26) which is a lower piezoelectric element provided on a Pt film 34, and a second piezoelectric element (15, 16) which is an upper piezoelectric element provided on the first piezoelectric element. The Pt film 26 serves as a common electrode for the first piezoelectric element (25, 26) and the second piezoelectric element (15, 16). However, the second piezoelectric element (15, 16) may have an electrode film separate from the Pt film 26. The first piezoelectric element has a single-crystal AlN film 25 as a first single-crystal piezoelectric film and a Pt film 26 as a first electrode film superimposed thereon. The second piezoelectric element has a single-crystal PZT film 15 as a second single-crystal piezoelectric film and a Pt film 16 as a second electrode film superimposed thereon. AlN is aluminum nitride. PZT is lead zirconate titanate. As the first single-crystal piezoelectric film, instead of the single-crystal AlN film 25, a piezoelectric film made of another single-crystal material such as a single-crystal lithium tantalate (single-crystal LiTaO3) film or a single-crystal lithium niobate (single-crystal LiNbO3) film may be used. As the second single-crystal piezoelectric film, instead of the single-crystal PZT film 15, a piezoelectric film made of another single-crystal material such as a single-crystal potassium sodium niobate (single-crystal KNN) film or a single-crystal barium titanate (single-crystal BaTiO3) film may be used. In the illustrated example, the first single-crystal piezoelectric film is a piezoelectric body that detects acoustic vibration waves (or their reflected waves), and it is desirable that it has a lower relative permittivity and higher detection sensitivity than the first single-crystal piezoelectric film. The second single-crystal piezoelectric film is a piezoelectric body that generates acoustic vibration waves, and it is desirable that it has a piezoelectric constant larger than the vibration amplitude of the second single-crystal piezoelectric film and is a piezoelectric body that can obtain a large vibration amplitude.

[0013] The lower piezoelectric element, the first piezoelectric element, may have a single-crystal PZT film and a Pt film as the first single-crystal piezoelectric film, while the upper piezoelectric element, the second piezoelectric element, may have a single-crystal AlN film and a Pt film superimposed on it.

[0014] Furthermore, the piezoelectric film integrated device 100 has an insulating film 35a and a wiring film 36a formed thereon, and an insulating film 35b and a wiring film 36b formed thereon.

[0015] The SOI substrate 33 has a Si substrate 30, a silicon oxide (SiO2) portion 31 as an insulating film, and a single-crystal silicon (single-crystal Si) portion 32. By etching the Si substrate 30 in the lower region of the single-crystal PZT film 15 and single-crystal AlN film 25 of the single-crystal silicon (single-crystal Si) portion 32 (i.e., the region overlapping the piezoelectric film), holes 71 (cavities) are formed, and the SiO2 portion 31 and single-crystal silicon (single-crystal Si) portion 32 located in the region where the holes 71 are formed function as a diaphragm. Furthermore, by forming the silicon oxide (SiO2) portion 31, which is made of a different material from the Si substrate 30, and giving it the function of an etching stop layer, it is possible to prevent variations in the thickness of the diaphragm due to the effects of etching. In addition, a substrate made of other materials such as a glass substrate or an organic film substrate may be used as the substrate instead of the SOI substrate 33. Holes 71 are formed in the Si substrate 30 of the SOI substrate 33 to expose the SiO2 portion 31. The hole 71 is formed in a circular shape, which corresponds to the shape of the single-crystal PZT film 15 or the single-crystal AlN film 25. Acoustic vibration waves generated in the single-crystal PZT film 15 are output from the hole 71, and the single-crystal AlN film 25 detects the reflected acoustic vibration waves through the hole 71.

[0016] The single-crystal AlN film 25 of the first piezoelectric element has a (0001) plane, which is a crystal plane parallel to the surface of the Pt film 34, and is an epitaxially grown film attached to the surface of the Pt film 34. The single-crystal PZT film 15 of the second piezoelectric element has a (001) plane, which is a crystal plane parallel to the surface of the Pt film 34, and is an epitaxially grown film attached to the surface of the Pt film 26 of the first piezoelectric element. The thickness of the single-crystal PZT film 15 is generally in the range of 10 nm to 10 μm, and preferably in the range of 100 nm to 5 μm. The thickness of the single-crystal AlN film 25 is generally in the range of 10 nm to 10 μm, and preferably in the range of 100 nm to 2 μm. The Pt film 34 is formed on the upper surface of the SOI substrate 33. The surface (top surface) of the Pt film 34 and the (0001) crystal plane of the single-crystal AlN film 25 are joined by intermolecular forces. The surface (top surface) of the Pt film 34 and the (0001) crystal plane of the single-crystal AlN film 25 are joined by intermolecular forces. The surface of the Pt film 26 of the first piezoelectric element and the (001) crystal plane of the single-crystal PZT film 15 are joined by intermolecular forces. Adhesives are not required for these joining. In order to join these well by intermolecular forces, it is desirable that the surface roughness of the Pt film 34 and the Pt film 26 be 10 nm or less. For this reason, the surfaces of the Pt film 34 and the Pt film 26 may be smoothed.

[0017] Furthermore, the crystal c-axis direction of the single-crystal PZT film 15 and the crystal c-axis direction of the single-crystal AlN film 25 are parallel. This will be explained later using Figure 23.

[0018] 《1-2》Structure of single-crystal PZT film Figure 5 is a schematic cross-sectional view showing the structure of an epitaxially grown film containing a single-crystal PZT film 15. Figure 6 is a diagram showing the crystal structure of the single-crystal PZT film 15 in Figure 5. Figure 7 is a schematic diagram showing the crystal structure of the epitaxially grown film in Figure 5. Note that in Figure 7, the vertical dimensions are significantly reduced compared to the horizontal dimensions.

[0019] The epitaxially grown film in Figure 5 is formed on a growth substrate 11, which is a single-crystal Si substrate. The epitaxially grown film in Figure 5 has a structure in which a single-crystal zirconium oxide (ZrO2) film 12, a single-crystal Pt film 13, a single-crystal SRO film 14, a single-crystal PZT film 15, and a single-crystal Pt film 16 are stacked in this order. The growth substrate 11 is an example of a substrate whose upper surface is a (100) plane. The ZrO2 film 12 is an example of an oriented film having a cubic crystal structure and whose upper surface is a (100) plane. The Pt film 13 is an example of a conductive film having a cubic crystal structure and whose upper surface is a (100) plane. The SRO film 14 is a SrRuO3 film (strontium ruthenate film) and is an example of an oriented film. The single-crystal PZT film 15 is an example of a single-crystal piezoelectric film for vibration output. When the single-crystal PZT film 15 contains a composite oxide having a perovskite-type structure, the single-crystal PZT film 15 can be epitaxially grown on the growth substrate 11 with a tetragonal orientation of (001). Furthermore, a Pt film 16 having a cubic crystal structure and being (100) oriented is epitaxially grown on the single-crystal PZT film 15.

[0020] "The ZrO2 film 12 is (100) oriented" means that the (100) plane of the ZrO2 film 12, which has a cubic crystal structure, is formed along the (100) plane of the growth substrate 11, that is, it is parallel to the (100) plane of the growth substrate 11. Furthermore, "parallel" includes the case where the angle between the top surface of the growth substrate 11 and the (100) plane of the ZrO2 film 12 is 20° or less. The meaning of "orientation" is similar among other films.

[0021] Table 1 shows the lattice constants of the single crystal Si in the growth substrate 11, the ZrO2 in the ZrO2 film 12, the Pt in the Pt film 13, the SRO in the SRO film 14, and the single crystal PZT in the single crystal PZT film 15.

[0022] [Table 1]

[0023] The lattice constant of Si is 0.543 nm, and the lattice constant of ZrO2 is 0.511 nm. The mismatch between the lattice constant of ZrO2 and that of Si is small, at 6.1%, indicating good compatibility between the lattice constant of ZrO2 and that of Si. Therefore, as shown in the schematic diagram Figure 7, the oriented ZrO2 film 12 can be epitaxially grown on the main plane of the growth substrate 11, which consists of the (100) plane. Consequently, the ZrO2 film 12 can be (100) oriented on the (100) plane of the growth substrate 11 with a cubic crystal structure, thereby improving the crystallinity of the ZrO2 film 12.

[0024] If the ZrO2 film 12 has a cubic crystal structure and is a (100) oriented zirconium oxide film, then the ZrO2 film 12 is along the upper surface, which is the main surface of the growth substrate 11. <100> The direction is aligned with the upper surface of the growth substrate 11. <100> It is oriented so as to be parallel to the direction.

[0025] Furthermore, along the upper surface of the growth substrate 11, the ZrO2 film 12 <100> The direction is aligned with the upper surface of the growth substrate 11. <100> Parallel to the direction means that the ZrO2 film 12 <100> The direction is aligned with the upper surface of the growth substrate 11. <100> Not only when perfectly parallel to the direction, but also the ZrO2 film 12 <100> Direction and along the upper surface of the growth substrate 11 <100> This includes cases where the angle with respect to the direction is 20° or less. Furthermore, the same applies to the in-plane orientation of other layers of the film, not just the ZrO2 film 12.

[0026] On the other hand, as shown in Table 1, the lattice constant of ZrO2 is 0.511 nm, and the lattice constant of Pt is 0.392 nm. However, when Pt is rotated 45° in the plane, the length of the diagonal becomes 0.554 nm, and the mismatch between the length of this diagonal and the lattice constant of ZrO2 is small, at 8.1%. For this reason, the Pt film 13 can be epitaxially grown on the (100) plane of the ZrO2 film 12.

[0027] Furthermore, as shown in Table 1, the lattice constant of Pt is 0.392 nm, and the lattice constant of SRO is 0.390-0.393 nm, and the mismatch between the lattice constant of Pt and the lattice constant of single crystal PZT is small, less than 0.5%. Therefore, the lattice constant of SRO matches well with that of Pt, and as shown in Figure 7, the SRO film 14 can be epitaxially grown on the (100) plane of the Pt film 13. Consequently, the SRO film 14 can be (100) oriented in a pseudocubic crystal representation on the (100) plane of the Pt film 13, and the crystallinity of the SRO film 14 can be improved.

[0028] When the single-crystal PZT film 15 has a tetragonal crystal structure and includes a (001) oriented PZT film, the lead zirconate titanate film is along the upper surface of the growth substrate 11 of the lead zirconate titanate film. <100> The direction is along the upper surface of the growth substrate 11. <100> It is oriented so as to be parallel to the direction.

[0029] A Pt film 16 is formed as an electrode by epitaxial growth of a (100) oriented PZT film 15 that is oriented (001). Since the electrode film on the single crystal PZT film 15 is the uppermost layer, it may be formed by other manufacturing methods.

[0030] 《1-3》Structure of a single-crystal AlN film Figure 8 is a schematic cross-sectional view showing the structure of an epitaxially grown film including a single-crystal piezoelectric film, a single-crystal AlN film 25. Figure 9(A) is a schematic diagram showing the (111) plane of the crystals of a single-crystal SRO film, a single-crystal Pt film, and a single-crystal ZrO2 film, and Figure 9(B) is a diagram showing the lattice constant of the crystal of the single-crystal SRO. Figure 10(A) is a schematic diagram showing the crystal structure of the single-crystal AlN film 25, and Figure 10(B) is a diagram showing the lattice constant of the crystal of the single-crystal AlN film 25.

[0031] The epitaxially grown film in Figure 8 is formed on a growth substrate 21, which is, for example, a single-crystal Si substrate. The epitaxially grown film has a structure in which a ZrO2 film 22, a Pt film 23, an SRO film 24, a single-crystal AlN film 25, and a Pt film 26 are stacked in this order. The growth substrate 21 is an example of a substrate whose upper surface is a (111) plane. The ZrO2 film 22 is an example of an oriented film having a cubic crystal structure and whose upper surface is a (111) plane. The Pt film 23 is an example of a conductive film having a cubic crystal structure and whose upper surface is a (111) plane. The SRO film 24 is a SrRuO3 film. The single-crystal AlN film 25 is an example of a single-crystal piezoelectric film for vibration detection (i.e., for input). The Pt film 26 is an example of an upper electrode. Figure 9(A) shows the top-down view of the (111) plane of the SRO cubic crystal. Figure 10(A) shows the top-down view of the (0001) plane, which is a crystal plane of the AlN hexagonal crystal.

[0032] When the single-crystal AlN film 25 is composed of hexagonal aluminum nitride, the single-crystal AlN film 25 can be epitaxially grown on the growth substrate 21 with a (0001) orientation in hexagonal representation. Furthermore, a Pt film 26 having a cubic crystal structure and oriented (100) can be epitaxially grown on the single-crystal AlN film 25.

[0033] "The ZrO2 film 22 is (111) oriented" means that the (111) plane of the ZrO2 film 22, which has a cubic crystal structure, is aligned with the (111) plane of the growth substrate 21, that is, parallel to the (111) plane of the growth substrate 21. Furthermore, "parallel" includes cases where the angle between the (111) plane of the ZrO2 film 22 and the main plane of the growth substrate 21 is 20° or less. The same applies to orientation between other layers.

[0034] Table 2 shows the lattice constants for Si, ZrO2, Pt, SRO, and single-crystal AlN.

[0035] [Table 2]

[0036] The lattice constant of Si is 0.543 nm, and the lattice constant of ZrO2 is 0.511 nm. The mismatch between the lattice constant of ZrO2 and that of Si is small, at 6.1%, indicating good lattice consistency between ZrO2 and Si. Therefore, the ZrO2 film 22 can be epitaxially grown on the main plane of the growth substrate 21, which consists of (111) planes. Consequently, the ZrO2 film 22 can be (111) oriented with a cubic crystal structure on the (111) plane of the growth substrate 21, thereby improving the crystallinity of the ZrO2 film 22. Figure 9(A) shows the (111) plane of a cubic crystal.

[0037] If the oriented film, ZrO2 film 22, has a cubic crystal structure and is a (111) oriented zirconium oxide film, then the ZrO2 film 12 is aligned along the upper surface, which is the main surface of the growth substrate 21. <111> The direction is along the upper surface of the growth substrate 21. <111> It is oriented so as to be parallel to the direction.

[0038] Furthermore, along the upper surface of the growth substrate 21, the ZrO2 film 22 <111> The direction is along the upper surface of the growth substrate 21. <111> Parallel to the direction means that the ZrO2 film 22 <111> The direction is aligned with the upper surface of the growth substrate 21. <111> Not only when perfectly parallel to the direction, but also the ZrO2 film 22 <111> Direction and along the upper surface of the growth substrate 21 <111> This includes cases where the angle with respect to the direction is 20° or less. The same applies to the orientation between layers of film.

[0039] On the other hand, the lattice constant of ZrO2 is 0.511 nm, and the lattice constant of Pt is 0.392 nm. However, when Pt is rotated 45° in the plane, the length of the diagonal becomes 0.554 nm. The mismatch between the length of this diagonal and the lattice constant of ZrO2 is small, at 8.1%, so the Pt film 23 can be epitaxially grown on the (111) plane of the ZrO2 film 22.

[0040] Furthermore, the lattice constant of Pt is 0.392 nm, and the lattice constant of SRO is 0.390 to 0.393 nm, indicating good compatibility between the lattice constant of SRO and that of Pt. Therefore, as shown in Figures 9(A) and (B)5, the SRO film 24 can be epitaxially grown on the (111) plane of the Pt film 23. Consequently, the SRO film 24 can be (111) oriented in a pseudocubic crystal representation on the (111) plane of the Pt film 23, thereby improving the crystallinity of the SRO film 24. The diagonal length of the (111) plane of the SRO film is 0.552 to 0.556 nm, and as shown in Figure 8, the mismatch with the width of the AlN hexagonal crystal (0.539 nm) is small at 2.8%, allowing the single-crystal AlN film 25 to be epitaxially grown on the (111) plane of the SRO film 24 in a (0001) orientation.

[0041] When the single-crystal AlN film 25 has a hexagonal crystal structure and includes an aluminum nitride film oriented to (0001), along the upper surface of the growth substrate 21 of the single-crystal AlN film 25 <111> The direction is the upper surface of the growth substrate 21 <111> The film is oriented parallel to the direction. Figures 10(A) and (B) show the (0001) plane of the hexagonal crystal. A Pt film 26 is then formed as an electrode by epitaxial growth in the (111) orientation on the (0001) oriented single crystal AlN film 25. Since the electrode film on the single crystal AlN film 25 is the uppermost layer, it may be formed by other manufacturing methods.

[0042] 《1-4》Manufacturing method A method for manufacturing a piezoelectric film integrated device 100 will be described using a PZT epitaxial growth film (including a single-crystal PZT film 15 and a Pt film 16) which is a piezoelectric element deposited on a growth substrate 11 whose upper surface is the (100) plane of single-crystal Si, and an AlN epitaxial growth film (including a single-crystal AlN film 25 and a Pt film 26) which is a piezoelectric element deposited on a growth substrate 21 whose upper surface is the (111) plane of single-crystal Si.

[0043] Figure 11 is a flowchart showing the manufacturing method of the piezoelectric film integrated device 100. Figures 12(A) and (B) show step ST102 of Figure 11. Figures 13(A) and (B) show step ST103 of Figure 11, and Figures 14(A) and (B) show step ST104 of Figure 11. Figures 15 and 16 show step ST109 of Figure 11. Figures 17(A) and (B) show step ST105 of Figure 11, and Figures 18(A) and (B) show step ST106 of Figure 11. Figures 19 and 20 show step ST107 of Figure 11. Figure 21 shows step ST108 of Figure 11, and Figure 22 shows step ST110 of Figure 11.

[0044] First, a wiring layer is formed on the SOI substrate 33, which is the device substrate (step ST101). Next, as shown in Figures 12(A) and (B), a Pt film 34 is formed on the main surface of the SOI substrate 33 as an electrode.

[0045] Furthermore, as shown in Figures 13(A) and (B), an SRO film 14, a single-crystal PZT film 15, and a Pt film 16 are epitaxially grown on a growth substrate 11, which is the first growth substrate (step ST103), and as shown in Figures 14(A) and (B), the single-crystal PZT film 15 and the Pt film 16 are etched into a circular shape (step ST104).

[0046] Furthermore, as shown in Figures 17(A) and (B), an SRO film 24, a single-crystal AlN film 25, and a Pt film 26 are epitaxially grown on a second growth substrate, the growth substrate 21 (step ST105), and as shown in Figures 18(A) and (B), the single-crystal AlN film 25 and the Pt film 26 are etched into a circular shape (step ST107).

[0047] Next, as shown in Figure 19, a piece consisting of a single crystal AlN film 25 and a Pt film 26 (i.e., a piezoelectric element which is an AlN epitaxially grown film) is held by a stamp 80 as a holding member, and as shown in Figure 20, the sacrificial layer, the SRO film 24, is etched to peel off the piece and move it onto the SOI substrate 33 (step ST108), and as shown in Figure 21, the piece consisting of a single crystal AlN film 25 and a Pt film 26 (i.e., a piezoelectric element which is an epitaxially grown film) is attached to the Pt film 34.

[0048] Next, as shown in Figure 15, a piece (in Embodiment 1, the second piezoelectric element) consisting of a single crystal PZT film 15 and a Pt film 16 is held by a stamp 80 as a holding member, and as shown in Figure 16, the sacrificial layer, the SRO film 14, is etched to peel off the piece, and as shown in Figure 22, it is moved onto the SOI substrate 33, which is the device substrate (step ST105).

[0049] Next, as shown in Figure 22, individual pieces (i.e., piezoelectric elements which are epitaxially grown films) consisting of a single crystal PZT film 15 and a Pt film 16 are attached to the Pt film 26 (step ST109). Next, an insulating film 35a and a wiring film 36a are formed on the single crystal PZT film 15 and the Pt film 16, and an insulating film 35b and a wiring film 36b are formed on the single crystal AlN film 25 and the Pt film 26.

[0050] Figure 23 shows the crystal c-axis of the first single-crystal piezoelectric film, a single-crystal PZT film 15, and the second single-crystal piezoelectric film, a single-crystal AlN film 25. As shown in Figure 23, when attaching them, the efficiency of piezoelectric vibration driving of the single-crystal PZT film 15 and piezoelectric vibration reception of the single-crystal AlN film 25 is maximized by arranging the hexagonal crystal structure of AlN and the cubic crystal structure of PZT so that their c-axises are parallel, as shown in the figure.

[0051] As shown in Figure 24, the back side of the piezoelectric element is thinned by etching the SOI substrate 33 down to the SiO2 portion 31, thereby creating a diaphragm. The thickness of the diaphragm can be adjusted to the desired thickness by controlling the thickness of each layer of the SOI substrate 33.

[0052] 《1-5》 Acoustic vibration sensor Figure 24 schematically shows the configuration of an acoustic vibration sensor using a semiconductor integrated device according to Embodiment 1. Figure 25 shows the operating principle of the acoustic vibration sensor. The upper and lower electrodes of the single crystal PZT film 15 are connected to the drive-receiving circuit 41, and by applying an AC bias of a frequency in the audible range or higher than the audible range to the electrodes of the single crystal PZT film 15, the single crystal PZT film 15 vibrates in the thickness direction, and the SiO2 part 31 vibrates similarly. Accordingly, acoustic vibration waves are radiated, and the reflected waves bounced off the object to be detected 90 cause the diaphragm of the SOI substrate 33 to which the single crystal AlN film 25 is attached to vibrate. The charge excited in the single crystal AlN film 25 by the vibration is amplified by the drive-receiving circuit 41, and the control circuit 42 calculates the distance to the object to be detected 90 based on the time difference Δt of receiving the reflected wave. The control circuit 42 and the drive-receiving circuit 41 are composed of electrical circuits or information processing devices.

[0053] 《1-6》 Variant Figure 26 is a schematic side view showing the structure of a piezoelectric film integrated device 100a according to a modified example of Embodiment 1. Figure 27 is a schematic top view showing the structure of the piezoelectric film integrated device 100a. Figure 28 is a cross-sectional view of the piezoelectric film integrated device 100a in Figure 27, cut along the line S28-S28. Figure 29 is a schematic bottom view showing the structure of the piezoelectric film integrated device 100a. When etching the SOI substrate 33 down to the SiO2 portion 31, the shape of the holes 72 may be a shape other than a circle, such as a square. It is desirable that the shape of the holes 72 corresponds to the planar shape of the piezoelectric element.

[0054] Effect 1-7 As explained above, single-crystal PZT film 15 and single-crystal AlN film 25, which are difficult to epitaxially grow on the same SOI substrate 33 due to their different lattice constants and crystal structures, can be epitaxially grown on separate growth substrates, peeled off from the growth substrates, and layered onto a common SOI substrate 33 to create a high-performance piezoelectric film integrated device 100.

[0055] Furthermore, since the single-crystal PZT film 15 has a higher piezoelectric constant than the polycrystalline PZT film, the amplitude of vibration can be easily increased.

[0056] Furthermore, since the single-crystal AlN film 25 has a lower dielectric constant than the polycrystalline AlN film, it can improve the sensitivity to vibration reception.

[0057] Furthermore, conventionally, forming dissimilar piezoelectric films involved complex processes such as covering one piezoelectric film with a protective layer and then removing the protective layer after forming the other piezoelectric film. Moreover, the heat applied during each process left residual stress and strain in the piezoelectric film, leading to a decrease in sensor efficiency. In the manufacturing method of Embodiment 1, since the attachment of epitaxially grown films, which are piezoelectric elements, is used, it is possible to construct piezoelectric film integrated devices and acoustic vibration sensors without residual stress and strain.

[0058] (2) Embodiment 2 《2-1》Structure Figure 30 is a schematic side view showing the structure of the piezoelectric film integrated device 200. Figure 31 is a schematic top view showing the structure of the piezoelectric film integrated device 200. Figure 32 is a cross-sectional view of the piezoelectric film integrated device 200 of Figure 31, cut along the line S32-S32.

[0059] In Embodiment 1, an AlN epitaxial growth film containing a single-crystal AlN film 25 and a Pt film 26 is grown on a growth substrate 21 and attached to a Pt film 34 on an SOI substrate 33. A PZT epitaxial growth film containing a single-crystal PZT film 15 and a Pt film 16 is grown on a growth substrate 11 and attached to an AlN epitaxial growth film attached to the Pt film 34 on the SOI substrate 33. Alternatively, in Embodiment 1, an AlN epitaxial growth film is attached to a PZT epitaxial growth film attached to a Pt film 34 on an SOI substrate 33. In contrast, in Embodiment 2, a PZT epitaxial growth film is grown on an SOI substrate 50. The upper surface of the SOI substrate 50 is a (100) plane. Therefore, it is possible to epitaxially grow a PZT epitaxial growth film on the SOI substrate 50 using the same process as in Embodiment 1.

[0060] 《2-2》Manufacturing method Figure 33 is a flowchart showing the manufacturing method of the piezoelectric film integrated device 200. Figure 34 shows step ST201 of Figure 33, and Figure 35 shows step ST202 of Figure 33. Figure 36 shows step ST207 of Figure 33.

[0061] First, as shown in Figure 34, a ZrO2 film 12 and a Pt film 13 as an electrode layer are formed on the main surface of the SOI substrate 50, which is the device substrate (step ST201). Furthermore, an SRO film 14, a single-crystal PZT film 15, and a Pt film 16 are epitaxially grown on the Pt film 13 to form an epitaxially grown film consisting of the SRO film 14, the single-crystal PZT film 15, and the Pt film 16 (step ST201). Next, as shown in Figure 35, the shape of the epitaxially grown film including the single-crystal PZT film 15 is etched to a desired shape (for example, a circular shape) (step ST202). Next, the Pt film 13 as an electrode layer is etched to form a Pt film 34 as an electrode, and a wiring layer is formed on the SOI substrate 30 (step ST203).

[0062] Next, individual pieces of the AlN epitaxial growth film (upper piezoelectric elements), consisting of a single-crystal AlN film 25 and a Pt film 26, are held by a stamp 80 as a holding member, the SRO film 24 which is a sacrificial layer is etched to peel off the individual pieces of the PZT epitaxial growth film, and as shown in Figure 36, they are moved onto the PZT epitaxial growth film on the SOI substrate 50 which is a device substrate and attached (steps ST204 to ST207). In other words, the piezoelectric elements having the single-crystal AlN film 25 and Pt film 26 as described in Embodiment 1 are attached onto the Pt film 16. When attaching, the crystal orientation of the single-crystal PZT film 15 is confirmed by inspection, etc., and the crystal orientation of the single-crystal PZT film 15 and the crystal orientation of the single-crystal AlN film 25 are aligned as shown in Figure 23. The orientation of the single-crystal PZT film 15 is fixed on the SOI substrate 50, so the bonding angle of the single-crystal AlN film 25 is adjusted. Alternatively, after confirming the crystal orientation during the etching process shown in Figure 35, the piezoelectric film may be formed by masking so that it is in the same direction as in Embodiment 1. As shown in Figure 30, an insulating film 35a and a wiring film (lead-out wiring) 36a are formed on the single-crystal PZT film 15 and the Pt film 16, and an insulating film 35b and a wiring film (lead-out wiring) 36b are formed on the single-crystal AlN film 25 and the Pt film 26.

[0063] Subsequently, the SOI substrate 50 is etched in the same manner as in Embodiment 1 to manufacture the piezoelectric film integrated device 200 shown in Figures 30 to 32.

[0064] 《2-3》Effect In Embodiment 2, by attaching an epitaxially grown film containing a single-crystal AlN film 25 to a Pt film 34 on an SOI substrate 50 having an epitaxially grown single-crystal PZT film 15, it becomes possible to obtain a single-crystal, high-performance piezoelectric film integrated device, similar to Embodiment 1.

[0065] In Embodiment 2, the alignment accuracy of the single-crystal PZT film 15 is improved compared to Embodiment 1. Therefore, in Embodiment 2, the output performance of the acoustic vibration wave is improved compared to Embodiments 1 and 3.

[0066] With respect to all other aspects, Embodiment 2 is the same as Embodiment 1.

[0067] (3) Embodiment 3 《3-1》Structure Figure 37 is a schematic side view showing the structure of the piezoelectric film integrated device 300. Figure 38 is a schematic top view showing the structure of the piezoelectric film integrated device 300. Figure 39 is a cross-sectional view of the piezoelectric film integrated device of Figure 38, cut along the line S39-S39.

[0068] In Embodiment 1, an AlN epitaxial growth film was grown on a growth substrate 21, a PZT epitaxial growth film was grown on a growth substrate 11, and the PZT epitaxial growth film was attached to an AlN epitaxial growth film that was attached to a Pt film 34 on an SOI substrate 33. Alternatively, in Embodiment 1, a PZT epitaxial growth film was attached to an AlN epitaxial growth film that was attached to a Pt film 34 on an SOI substrate 33, and an AlN epitaxial growth film was attached to a PZT epitaxial growth film. In contrast, in Embodiment 3, the PZT epitaxial growth film is grown on an SOI substrate 60. The upper surface of the SOI substrate 60 is a (111) plane. Therefore, it is possible to epitaxially grow an AlN epitaxial growth film on the SOI substrate 60 using the same process as in Embodiment 3.

[0069] 《3-2》Manufacturing method Figure 40 is a flowchart showing the manufacturing method of the piezoelectric film integrated device 300. Figure 41 shows step ST301 of Figure 40, and Figure 42 shows step ST302 of Figure 40. Figure 43 shows step ST307 of Figure 33.

[0070] First, as shown in Figure 41, a ZrO2 film 22 and a Pt film 23 as an electrode layer are formed on the main surface of the SOI substrate 60, which is the device substrate. Furthermore, an SRO film 24, a single-crystal AlN film 25, and a Pt film 16 are epitaxially grown on the Pt film 23 to form an epitaxially grown film consisting of the SRO film 24, the single-crystal AlN film 25, and the Pt film 26 (step ST301). Next, as shown in Figure 42, the shape of the epitaxially grown film including the single-crystal AlN film 25 is etched to a desired shape (for example, a circular shape) (step ST302). Next, the Pt film 23 as an electrode layer is etched to form a Pt film 34 as a first electrode, and a wiring layer is formed on the SOI substrate 30 (step ST303).

[0071] Next, individual pieces of the PZT epitaxial growth film (upper piezoelectric elements), consisting of a single-crystal PZT film 15 and a Pt film 16, are held by a stamp 80 as a holding member, the sacrificial layer, the SRO film 14, is etched to peel off the individual pieces of the PZT epitaxial growth film, and as shown in Figure 43, they are moved onto the AlN epitaxial growth film on the SOI substrate 60, which is the device substrate, and attached (steps ST304 to ST307). In other words, the piezoelectric elements having the single-crystal PZT film 15 and the Pt film 16 as described in Embodiment 1 are attached onto the Pt film 26. When attaching, the crystal orientation of the single-crystal PZT film 15 is confirmed by inspection, etc., and the crystal orientation of the single-crystal PZT film 15 and the crystal orientation of the single-crystal AlN film 25 are aligned as shown in Figure 23. The orientation of the single-crystal AlN film 25 is fixed on the SOI substrate 60, so the bonding angle of the single-crystal PZT film 15 is adjusted. Alternatively, after confirming the crystal orientation during the etching process shown in Figure 35, the piezoelectric film may be formed by masking so that it is in the same direction as in Embodiment 1. As shown in Figure 39, an insulating film 35a and a wiring film (lead-out wiring) 36a are formed on the single-crystal PZT film 15 and the Pt film 16, and an insulating film 35b and a wiring film (lead-out wiring) 36b are formed on the single-crystal AlN film 25 and the Pt film 26.

[0072] Subsequently, the SOI substrate 60 is etched in the same manner as in Embodiment 1 to manufacture the piezoelectric film integrated device 200 shown in Figures 37 to 39.

[0073] 《3-3》Effect In Embodiment 3, by attaching an epitaxially grown film containing a single-crystal PZT film 15 to an AlN epitaxially grown film having an epitaxially grown single-crystal AlN film 25 and a Pt film 26, it becomes possible to obtain a high-performance piezoelectric film integrated device 300 using multiple single-crystal piezoelectric films, similar to Embodiment 1.

[0074] In Embodiment 3, the alignment accuracy of the single-crystal AlN film 25 is improved compared to Embodiment 1. Therefore, in Embodiment 3, the detection sensitivity of acoustic vibration waves and the signal-to-noise ratio are improved compared to Embodiments 1 and 2.

[0075] With respect to all other matters, Embodiment 3 is the same as Embodiment 1 or 2.

[0076] (4) Modification Example 1 The piezoelectric film integrated device 500 of Modified Example 1 differs from the piezoelectric film integrated device 100 of Embodiment 1 in that the epitaxial growth film attached to the Pt film 34 on the SOI substrate 33 is composed of a Pt film 126, a single-crystal AlN film 25, and a Pt film 26, and the epitaxial growth film attached to the Pt film 26 is composed of a Pt film 116, a single-crystal PZT film 15, and a Pt film 16. In all other respects, the piezoelectric film integrated device 500 of Modified Example 1 is the same as the piezoelectric film integrated device 100 of Embodiment 1.

[0077] Figure 44 is a cross-sectional view showing the state in which Pt film 13, SRO film 14, Pt film 116, single crystal PZT film 15, and Pt film 16 are sequentially epitaxially grown on a ZrO2 film 12 on a Si substrate 11. Figure 45 is a cross-sectional view showing the state in which Pt film 23, SRO film 24, Pt film 126, single crystal AlN film 25, and Pt film 26 are sequentially epitaxially grown on a ZrO2 film 22 on a Si substrate 21.

[0078] Figure 46 is a schematic cross-sectional view showing the structure of the piezoelectric film integrated device 500 of Modification 1. Figure 47 is a schematic top view showing the structure of the piezoelectric film integrated device 500 of Figure 46. In Figures 46 and 47, components that are the same as or corresponding to those shown in Figures 1 to 4 (Embodiment 1) are denoted by the same reference numerals as in Figures 1 to 4. In the piezoelectric film integrated device 500 of Modification 1, an epitaxial growth film (shown in Figure 45) composed of a Pt film 126, a single crystal AlN film 25, and a Pt film 26 is attached to the Pt film 34, and an epitaxial growth film (shown in Figure 44) composed of a Pt film 116, a single crystal PZT film 15, and a Pt film 16 is attached to the Pt film 26. Apart from this point, the piezoelectric film integrated device 500 of Modification 1 is the same as the piezoelectric film integrated device 100 according to Embodiment 1.

[0079] Furthermore, an epitaxial growth film (shown in Figure 44) composed of a Pt film 116, a single-crystal PZT film 15, and a Pt film 16 can be used in place of the epitaxial growth film composed of a single-crystal PZT film 15 and a Pt film 16 in the piezoelectric film integrated device 200 or 300 according to Embodiment 2 or 3 (shown in Figures 30 to 32 and 37 to 39). Also, an epitaxial growth film (shown in Figure 45) composed of a Pt film 126, a single-crystal AlN film 25, and a Pt film 26 can be used in place of the epitaxial growth film composed of a single-crystal AlN film 25 and a Pt film 26 in the piezoelectric film integrated device 200 or 300 according to Embodiment 2 or 3 (shown in Figures 30 to 32 and 37 to 39).

[0080] (5) Modified example 2 The piezoelectric film integrated devices 100, 200, 300 and the acoustic vibration sensor 400 according to the embodiment can be used not only as distance sensors but also as other sensors such as fingerprint sensors and vein (pulse wave) sensors.

[0081] Furthermore, a piezoelectric film integrated device in which pairs of single-crystal PZT films 15 and single-crystal AlN films 25 are arranged in a matrix makes it possible to detect the surface shape of an object to be detected. [Explanation of Symbols]

[0082] 100, 100a, 200, 300, 500 Piezoelectric film integrated devices, 400 Acoustic vibration sensors, 11, 21 Growth substrates (single crystal Si substrates), 15 Single crystal PZT film (first single crystal piezoelectric film), 16 Pt film (electrode film), 14, 24 SRO film (orientation film), 25 Single crystal AlN film (second single crystal piezoelectric film), 26 Pt film (electrode film), 31 SiO2 portion, 32 Single crystal Si portion, 33, 50, 60 SOI substrates (substrates), 34 Pt film (electrodes), 71, 72 Holes, 116 Pt film, 126 Pt film.

Claims

1. circuit board and An electrode provided on the substrate, A first piezoelectric element comprising a first single-crystal piezoelectric film and a first electrode film overlapping the first single-crystal piezoelectric film, and provided on the electrode, A second piezoelectric element is provided on the first piezoelectric element, comprising a second single-crystal piezoelectric film having a crystal structure different from that of the first single-crystal piezoelectric film, and a second electrode film overlapping the second single-crystal piezoelectric film. It has, At least one of the first single-crystal piezoelectric film and the second single-crystal piezoelectric film is an epitaxially grown film that was grown on a growth substrate different from the substrate. A piezoelectric film integrated device characterized by the following features.

2. The substrate has a diaphragm provided in the lower region of the first single-crystal piezoelectric film. The piezoelectric film integrated device according to feature 1.

3. The aforementioned substrate is a Si substrate and SiO ２ It is an SOI substrate having a part and a single-crystal Si part, The diaphragm is made of SiO ２ Having a part and the single crystal Si part, The piezoelectric film integrated device according to feature 2.

4. The first single-crystal piezoelectric film is a single-crystal PZT film, a single-crystal KNN film, or a single-crystal barium titanate film. The second single-crystal piezoelectric film is a single-crystal AlN film, a single-crystal lithium tantalate film, or a single-crystal lithium niobate film. A piezoelectric film integrated device according to any one of claims 1 to 3.

5. The first single-crystal piezoelectric film is a single-crystal AlN film, a single-crystal lithium tantalate film, or a single-crystal lithium niobate film. The second single-crystal piezoelectric film is a single-crystal PZT film, a single-crystal KNN film, or a single-crystal barium titanate film. A piezoelectric film integrated device according to any one of claims 1 to 3.

6. The first single-crystal piezoelectric film has a (001) plane, which is a crystal plane parallel to the surface of the electrode. The first piezoelectric element is an epitaxially grown film attached to the surface of the electrode. A piezoelectric film integrated device according to any one of claims 1 to 3.

7. The electrode further comprises an SRO film formed on the electrode, The first single-crystal piezoelectric film has a (001) plane which is a crystal plane parallel to the surface of the SRO film, The first piezoelectric element is an epitaxially grown film formed on the surface of the SRO film. A piezoelectric film integrated device according to any one of claims 1 to 3.

8. The second single-crystal piezoelectric film has a (0001) plane, which is a crystal plane parallel to the surface of the electrode. The second piezoelectric element is an epitaxially grown film attached to the surface of the first electrode film. The piezoelectric film integrated device according to claim 6 or 7.

9. The first single-crystal piezoelectric film has a (0001) plane, which is a crystal plane parallel to the surface of the electrode. The first piezoelectric element is an epitaxially grown film attached to the surface of the electrode. A piezoelectric film integrated device according to any one of claims 1 to 3.

10. The electrode further comprises an SRO film formed on the electrode, The first single-crystal piezoelectric film has a (0001) plane, which is a crystal plane parallel to the surface of the SRO film. The first piezoelectric element is an epitaxially grown film formed on the surface of the SRO film. A piezoelectric film integrated device according to any one of claims 1 to 3.

11. The second single-crystal piezoelectric film has a (001) plane, which is a crystal plane parallel to the surface of the electrode. The second piezoelectric element is an epitaxially grown film attached to the surface of the first electrode film. The piezoelectric film integrated device according to claim 9 or 10.

12. The crystal c-axis direction of the first single-crystal piezoelectric film and the crystal c-axis direction of the second single-crystal piezoelectric film are parallel to each other. A piezoelectric film integrated device according to any one of claims 1 to 11.

13. The piezoelectric film integrated device according to any one of claims 1 to 12, One of the first single-crystal piezoelectric film and the second single-crystal piezoelectric film outputs an acoustic vibration wave consisting of at least one of sound waves and ultrasonic waves. The other of the first single-crystal piezoelectric film and the second single-crystal piezoelectric film detects the reflected waves of the acoustic vibration waves. An acoustic vibration sensor characterized by the following features.

14. A first epitaxial growth film, which is a first piezoelectric element having a first single-crystal piezoelectric film and a first electrode film overlapping the first single-crystal piezoelectric film, is grown on a first crystal plane of a growth substrate. A second epitaxial growth film, which is a second piezoelectric element, is grown on a second crystal plane of another growth substrate, having a second single-crystal piezoelectric film having a crystal structure different from that of the first single-crystal piezoelectric film, and a second electrode film overlapping the second single-crystal piezoelectric film. A first epitaxial growth film, peeled off from the growth substrate, is attached to a substrate having electrodes, and a second epitaxial growth film, peeled off from the other growth substrate, is attached to the first epitaxial growth film. A method for manufacturing a piezoelectric film integrated device, characterized by the above.

15. A first epitaxial growth film, which is a first piezoelectric element, is grown on a first crystal plane of a substrate having electrodes, and the first film is a first single-crystal piezoelectric film and a first electrode film overlapping the first single-crystal piezoelectric film. A second epitaxial growth film, which is a second piezoelectric element, is grown on a second crystal plane of a growth substrate, having a second single-crystal piezoelectric film having a crystal structure different from that of the first single-crystal piezoelectric film, and a second electrode film overlapping the second single-crystal piezoelectric film. The second epitaxial growth film, peeled off from the growth substrate, is attached to the first epitaxial growth film. A method for manufacturing a piezoelectric film integrated device, characterized by the above.

16. The crystal c-axis direction of the first single-crystal piezoelectric film and the crystal c-axis direction of the second single-crystal piezoelectric film are parallel to each other. A method for manufacturing a piezoelectric film integrated device according to claim 14 or 15.

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