Piezoelectric element, manufacturing method, actuator and electronic equipment

Abstract

The embodiment of the invention provides a piezoelectric element, a manufacturing method, an actuator and electronic equipment, and relates to the technical field of semiconductors. The piezoelectric element comprises a substrate, wherein the substrate comprises a cavity penetrating through the substrate; a vibration layer is arranged on the substrate and covers the cavity; the first electrode, the piezoelectric film layer and the second electrode are arranged on the vibration layer in a stacked mode, and the first electrode is in lattice matching with the vibration layer. According to the piezoelectric element provided by the embodiment of the invention, the buffer layer is used as the vibration layer, and a grinding process does not need to be used for the vibration layer, so that the film thickness error of the vibration layer is relatively small, and the performance of the piezoelectric element is improved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and in particular to a piezoelectric element, a manufacturing method, an actuator and an electronic device. Background Art

[0002] In recent years, with the development of the semiconductor industry, microelectromechanical systems (MEMS) devices based on piezoelectric elements have been proposed. In the manufacturing process of existing MEMS devices, errors will inevitably occur, which will reduce the performance of the MEMS devices. Summary of the invention

[0003] Embodiments of the present application provide a piezoelectric element, a manufacturing method, an actuator, and an electronic device for reducing errors in the manufacturing process of the piezoelectric element.

[0004] In order to achieve the above objectives, the embodiments of the present application provide the following technical solutions:

[0005] In a first aspect, a piezoelectric element is provided, which includes: a substrate, the substrate including a cavity penetrating the substrate; a vibration layer disposed on the substrate, the vibration layer covering the cavity; a first electrode, a piezoelectric film layer, and a second electrode stacked on the vibration layer, the first electrode being lattice-matched with the vibration layer.

[0006] The piezoelectric element provided in this embodiment includes a stacked substrate, a vibration layer, a first electrode, a piezoelectric film layer, and a second electrode. The cavity in the substrate provides a vibration space for the vibration layer, and the first electrode and the vibration layer are lattice matched, so that the piezoelectric film layer has good piezoelectric properties. In this embodiment, a voltage is applied to the first electrode and the second electrode to form an electric field between the first electrode and the second electrode. Under the action of the electric field, the piezoelectric film layer is deformed and the vibration layer is vibrated, thereby converting electrical energy into mechanical energy. Since a vibration layer of a preset thickness can be directly formed when forming the vibration layer, there is no need to use a grinding process for the vibration layer, so the film thickness error of the vibration layer is small, thereby improving the performance of the piezoelectric element.

[0007] In a possible implementation, the thickness of the vibration layer is 200 nm-8000 nm.

[0008] In this embodiment, the vibration layer needs to have an increased thickness. The increased thickness of the vibration layer means that the lateral dimension of the vibration layer becomes larger, which increases the lateral constraint on the vibration layer. The lateral constraint can make the vibration layer produce greater resistance when subjected to force, thereby improving the stiffness. Therefore, the thickness of the vibration layer can be 200nm-8000nm, so that the vibration layer has a certain stiffness.

[0009] In a possible implementation, the material of the vibration layer includes at least one or more of the following combinations: zirconium oxide, yttrium-stabilized zirconium oxide, hafnium oxide, and hafnium zirconium oxide.

[0010] In a possible implementation, the material of the substrate includes at least one or more of the following combinations: silicon, germanium, silicon carbide, gallium arsenide, indium arsenide, and indium phosphide. The substrate manufacturing process is simple and the cost is low. At the same time, the substrate has good mechanical properties, for example, the substrate has high mechanical strength, high linearity, low creep mechanical properties, and low internal stress, so it can improve the output displacement, force or rotation angle of the actuator, as well as better linearity, consistency and reliability.

[0011] In a possible implementation, a first buffer layer is further provided between the first electrode and the piezoelectric film layer. The first buffer layer can serve as an adhesion layer between the first electrode and the piezoelectric film layer to prevent the piezoelectric film layer from peeling off from the first electrode. At the same time, the first buffer layer can also serve as a barrier layer to prevent the material forming the piezoelectric film layer from diffusing into the first electrode.

[0012] In a possible implementation, a second buffer layer is further provided between the piezoelectric film layer and the second electrode. The third buffer layer can serve as an adhesion layer between the piezoelectric film layer and the second electrode to prevent the piezoelectric film layer from peeling off from the second electrode. At the same time, the second buffer layer can also serve as a barrier layer to prevent the material forming the piezoelectric film layer from diffusing into the second electrode.

[0013] In a possible implementation manner, the first electrode and the piezoelectric film layer are lattice matched.

[0014] In a second aspect, a method for manufacturing a piezoelectric element is provided. The method for manufacturing the piezoelectric element includes: forming a substrate; forming a vibration layer covering the substrate, wherein the thickness of the vibration layer is greater than a first threshold; forming a first electrode on the vibration layer, wherein the first electrode and the vibration layer are lattice matched; forming a piezoelectric film layer on the first electrode; forming a second electrode on the piezoelectric film layer; and forming a cavity on the substrate that penetrates the substrate.

[0015] In a possible implementation, forming a cavity penetrating the substrate on the substrate includes: etching the substrate from a side of the substrate away from the vibration layer to form a cavity penetrating the substrate on the substrate, and the vibration layer is used as an etching stop layer.

[0016] In a possible implementation, before forming the piezoelectric film layer, the forming method further includes: forming a first buffer layer on the first electrode.

[0017] In a possible implementation, before forming the second electrode, the forming method further includes: forming a second buffer layer on the piezoelectric film layer.

[0018] In a possible implementation, forming the piezoelectric film layer includes: depositing a precursor solution of the piezoelectric film layer on the first electrode, and drying the precursor solution to form a thin film layer; and calcining the thin film layer to form the piezoelectric film layer.

[0019] In a third aspect, an actuator is provided, comprising a drive circuit and a piezoelectric element, wherein a first end of the drive circuit is electrically connected to a first electrode of the piezoelectric element; and a second end of the drive circuit is electrically connected to a second electrode of the piezoelectric element.

[0020] According to a fourth aspect, an electronic device is provided. The electronic device includes a printed circuit layer and an actuator, wherein the printed circuit layer is electrically connected to the actuator.

[0021] Among them, the technical effects brought about by any possible implementation method of the second aspect and the fourth aspect can refer to the technical effects brought about by different implementation methods of the above-mentioned first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A schematic diagram of the structure of a piezoelectric element provided in an embodiment of the present application;

[0024] Figure 2 A schematic diagram of the structure of a piezoelectric element provided in another embodiment of the present application;

[0025] Figure 3 A schematic diagram of a process for manufacturing a piezoelectric element according to an embodiment of the present application;

[0026] Figure 4-Figure 12 A schematic diagram of the structure of a piezoelectric element at various stages in the manufacturing process provided by another embodiment of the present application;

[0027] Fig.13 A schematic diagram of the structure of an actuator provided in an embodiment of the present application;

[0028] Fig.14 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0030] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0031] Additionally, for ease of description, spatially relative terms such as "bottom," "below," "below," "above," "above," etc. may be used herein to describe the relationship of one component or feature to another component, or function as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly.

[0032] With the progress of science and technology, electronic and mechanical systems are developing towards miniaturization and micro-miniaturization. The high-density, multi-functional and intelligent integration of chips has become an important research direction, thus giving birth to MEMS technology characterized by miniaturization, integration and intelligence. Actuators, micro-sensors, micro-optical systems, radio frequency systems, micro-chips, micro-fluidic devices, stereo integrated circuits and other electronic devices based on MEMS technology have been widely used in industry, biology, medicine and other industries.

[0033] At present, the actuator is the most basic structural unit of MEMS devices and the basis for realizing various functions. The piezoelectric element in the actuator is an important factor affecting the performance of the actuator. To this end, the embodiment of the present application provides a piezoelectric element. Figure 1 The piezoelectric element includes a silicon on insulator (SOI) substrate 110, and a third buffer layer 115, a first electrode 130, a piezoelectric film layer 140 and a second electrode 150 stacked on the SOI substrate.

[0034] The SOI substrate 110 includes a stacked substrate 101, an insulating layer 102 and a device silicon layer 103. The substrate includes a cavity 104 that penetrates the substrate, and the cavity 104 provides a vibration space for the device silicon layer 103 used for the vibration layer. The insulating layer 102 is between the substrate 101 and the device silicon layer 103, and is used to achieve electrical isolation between the substrate and the device silicon layer. The insulating layer 102 can be a silicon oxide layer obtained by thermal oxygen growth or chemical vapor deposition (CVD). The material of the device silicon layer 103 and the substrate 101 can be the same or different. For example, the material of the substrate 101 and the device silicon layer 103 is a silicon-based material, a ceramic material or a polymer material. In addition, the substrate 101 and the device silicon layer 103 can also include other element semiconductors (such as germanium), or other compound semiconductors (such as silicon carbide, gallium arsenide, indium arsenide, indium phosphide, etc.). The thickness of the device silicon layer 103 can be flexibly set according to the requirements of different actuators for the vibration layer.

[0035] Since the first electrode 130 is directly formed on the device silicon layer 103, the lattice mismatch between the first electrode 130 and the piezoelectric film layer 140 will cause the piezoelectric properties of the piezoelectric film layer to be poor, a third buffer layer 115 is also provided on the device silicon layer 103 in the embodiment of the present application. Since the third buffer layer in the present embodiment is only used to make the lattice match between the first electrode and the piezoelectric film layer 140 formed subsequently, in order to save costs, the third buffer layer 115 can have a thinner thickness. Exemplarily, the thickness of the third buffer layer 115 can be 60nm. The third buffer layer 115 includes at least one or more of the following combinations: zirconium oxide (ZrO2), yttrium stabilized zirconium oxide (YSZ), hafnium oxide (HfO2), and hafnium zirconium oxide (HfZrO2).

[0036] A voltage can be applied to the first electrode 130 and the second electrode 150, so that an electric field can be formed between the first electrode 130 and the second electrode 150. Under the influence of the electric field, the piezoelectric film layer 140 is deformed, and the device silicon layer 103 used as a vibration layer vibrates, so that the inverse piezoelectric effect can be used to convert electrical energy into mechanical energy.

[0037] In a specific embodiment, the process of manufacturing the above-mentioned piezoelectric element is as follows: first, an SOI substrate is formed, and the formed SOI substrate includes: a substrate 101, an insulating layer 102, and a device silicon layer 103. Then, a third buffer layer 115 is formed on the device silicon layer 103, and a first electrode 130, a piezoelectric film layer 140, and a second electrode 150 are sequentially formed on the third buffer layer 115. Finally, an etching process is performed on the substrate 101 on a side away from the insulating layer 102 to form a cavity 104 penetrating the substrate 101, and the insulating layer 102 is used as an etching stop layer.

[0038] The piezoelectric element provided in this embodiment includes a stacked SOI substrate 110, a third buffer layer 115, a first electrode 130, a piezoelectric film layer 140 and a second electrode 150. A voltage is applied to the first electrode 130 and the second electrode 150 to form an electric field between the first electrode 130 and the second electrode 150. Under the action of the electric field, the piezoelectric film layer 140 is deformed, and the device silicon layer 103 as a vibration layer is vibrated, thereby converting electrical energy into mechanical energy. However, compared with other silicon substrates, the SOI substrate used in this embodiment has an increased cost due to the increase in the number of processes. At the same time, the SOI substrate may be a pre-formed substrate. Therefore, in order to meet the requirements of different types of actuators for the thickness of the vibration layer, it is generally necessary to thin the device silicon layer 103 through a grinding process so that the device silicon layer 103 has a preset thickness. However, the grinding process will cause a large deviation in the film thickness of the device silicon layer 103, and the film thickness error of the grinding process is generally ±0.3um. This error will directly lead to errors in the actuator, for example, affecting the displacement and resonance frequency, which are important characteristics of the actuator. This may reduce the margin of actuator design and process and become an obstacle to the development of the actuator.

[0039] To this end, the present application provides a piezoelectric element, see Figure 2 The piezoelectric element includes: a substrate 101, the substrate 101 includes a cavity 104 penetrating the substrate 101; a vibration layer 120 is arranged on the substrate 101, and a first electrode 130, a piezoelectric film layer 140 and a second electrode 150 are stacked on the vibration layer 120. The cavity 104 in the substrate 101 provides a vibration space for the vibration layer 120, and the vibration layer 120 also plays the role of the third buffer layer 115 in the above embodiment, that is, the vibration layer 120 is lattice-matched with the first electrode 130, so that the piezoelectric film layer 140 has good piezoelectric characteristics.

[0040] In an alternative embodiment, see Figure 3 Schematic diagram of the manufacturing process of the piezoelectric element is shown, and the process of manufacturing the above-mentioned piezoelectric element is: S10: forming a substrate 101; S20: forming a vibration layer 120 on the substrate 101; S30: forming a first electrode 130 on the vibration layer 120, and the first electrode 130 and the vibration layer 120 are lattice matched; S40: forming a piezoelectric film layer 140 on the first electrode 130; S50: forming a second electrode 150 on the piezoelectric film layer 140; S60: forming a cavity 104 on the substrate 101 that penetrates the substrate 101.

[0041] The piezoelectric element provided in this embodiment includes a stacked substrate 101, a vibration layer 120, a first electrode 130, a piezoelectric film layer 140, and a second electrode 150. A voltage is applied to the first electrode 130 and the second electrode 150 to form an electric field between the first electrode 130 and the second electrode 150. Under the action of the electric field, the piezoelectric film layer is deformed, and the vibration layer 120 vibrates, thereby converting electrical energy into mechanical energy. Since the vibration layer 120 of a preset thickness can be directly formed when forming the vibration layer 120, there is no need to use a grinding process for the vibration layer 120, so the film thickness error of the vibration layer 120 is small, thereby improving the performance of the piezoelectric element.

[0042] In an optional embodiment, the manufacturing process of the piezoelectric element and the device structure formed during the manufacturing process are described in detail below.

[0043] S10: forming a substrate 101.

[0044] like Figure 4 As shown, the piezoelectric element includes a substrate 101. Exemplarily, the thickness of the substrate 101 can be a standard thickness of 300μm to 800μm. In this embodiment, the substrate 101 can be a single crystal silicon substrate. Compared with SOI substrates, the manufacturing process of single crystal silicon substrates is simple and the cost is low. At the same time, the single crystal silicon substrate has good mechanical properties, for example, the single crystal silicon substrate has high mechanical strength, high linearity, low creep mechanical properties, and low internal stress, so it can improve the output displacement, force or angle of the actuator, as well as better linearity, consistency and reliability. In some other embodiments, the substrate 101 can also be made of silicon or other semiconductor materials. Optionally or additionally, the substrate 101 can include other elemental semiconductor materials such as germanium. In some embodiments, the substrate 101 is made of a compound semiconductor, such as silicon carbide, gallium arsenide, indium arsenide or indium phosphide.

[0045] S20: forming a vibration layer 120 on the substrate 101.

[0046] like Figure 5 The structural diagram of the piezoelectric element shown in the figure, the vibration layer 120 covers the substrate 101, and the material of the vibration layer 120 includes at least one or more of the following combinations: zirconium oxide (ZrO2), yttrium stabilized zirconium oxide (YSZ), hafnium oxide (HfO2), hafnium zirconium oxide (HfZrO2). The vibration layer 120 can be formed by a metal organic chemical vapor deposition (MOCVD) process, an electron beam evaporation process, a sputtering process or other applicable processes.

[0047] The stiffness of the vibration layer has an important influence on its natural frequency and resonant frequency. Higher stiffness can make the natural frequency of the vibration layer higher, thereby improving its frequency stability. At the same time, when the piezoelectric element is used in an actuator, the sensitivity of the vibration layer is an important indicator. Higher stiffness can make the vibration layer more sensitive to external excitation, that is, it is easier to produce displacement or response, thereby improving the performance of the actuator.

[0048] Therefore, a third buffer layer 115 that is too thin, for example, a third buffer layer 115 with a thickness of 60 nm in the above embodiment, cannot meet the stiffness requirements of the vibration layer. Therefore, compared with the third buffer layer 115 provided in the above embodiment, the vibration layer 120 in this embodiment needs to have an increased thickness. The increase in the thickness of the vibration layer 120 means that the lateral dimension of the vibration layer 120 becomes larger, which will increase the lateral constraint on the vibration layer 120. The lateral constraint can make the vibration layer 120 produce greater resistance when subjected to force, thereby improving the stiffness. Therefore, during the formation process, the thickness of the vibration layer 120 should be controlled to be greater than the first threshold so that the vibration layer 120 has a certain stiffness. In an optional embodiment, the thickness of the vibration layer 120 is 200nm-8000nm.

[0049] It is understandable that setting the first threshold too high will make the vibration layer have too high stiffness, which will cause the vibration layer to be too rigid and unable to achieve the desired vibration response. Setting the first threshold too low will make the stiffness of the vibration layer too low, which may cause the vibration layer to be too soft and unable to provide stable vibration characteristics. Therefore, the first threshold can be set according to the rigidity requirements of the vibration layer. For example, when the piezoelectric element is applied to an actuator that requires a small deformation, the first threshold can be set to 2μm; when the piezoelectric element is applied to an actuator that requires a large deformation, the first threshold can be set to 200nm.

[0050] S30 : forming the first electrode 130 on the vibration layer 120 .

[0051] Because, when piezoelectric elements are applied to actuators, miniaturization, low-voltage driving, and high-speed driving are pursued. The higher the piezoelectric constant of the piezoelectric element, the more effectively it can be driven relative to the input voltage, and the larger the capacitance of the piezoelectric element, the greater the power consumption during driving and the heat generated by the element itself. Therefore, for piezoelectric elements generally used in actuators, it is necessary to have a higher piezoelectric constant and a lower dielectric constant. The crystal orientation of the piezoelectric film layer (referred to as crystal orientation) has a great influence on the piezoelectric properties of the piezoelectric element, especially the piezoelectric properties such as conversion efficiency, dielectric constant, and dielectric loss. Therefore, the film forming state of the first electrode 130 is also more important.

[0052] In this embodiment, if Figure 6The schematic diagram of the structure of the piezoelectric element shown in the figure can form the first electrode 130 on the vibration layer 120 by a sputtering process or an electronic evaporation process. The material of the first electrode 130 can be a polysilicon material or a metal material, and the metal material can include one or more of the following combinations: platinum (Pt), gold (AU), copper (AU), and aluminum (Al). It can be understood that the material of the first electrode 130 in the embodiment of the present application can also be other materials, as long as the material of the first electrode 130 and the material of the vibration layer 120 are lattice-matched.

[0053] In order to make the subsequently formed piezoelectric film layer 140 have good piezoelectric properties, in a specific example, the crystal orientation of the first electrode 130 is <100> It can be understood that the crystal orientation of the first electrode 130 is <100> It means that the orientation of most crystals in the first electrode 130 is <100> , for example, 90% of the crystals in the first electrode are oriented <100> There may be a small amount of other crystal orientations in the first electrode 130, for example, there may be a crystal orientation of <001> of crystals.

[0054] S35 : forming a first buffer layer 135 on the first electrode 130 .

[0055] In this embodiment, if Figure 7 The schematic diagram of the structure of the piezoelectric element shown in FIG. 1 is a schematic diagram of the structure of the piezoelectric element, wherein a first buffer layer 135 is formed on the first electrode 130 by a sputtering process, a chemical solution deposition process or other suitable process. The material forming the first buffer layer 135 includes one or more of the following combinations: strontium ruthenate (SRO), lead lanthanum titanate ((Pb, La)TiO3), and lanthanum nickelate (LaNiO3). The crystal orientation of the first buffer layer 135 is the same as that of the first electrode 130, both of which are <100> , to ensure that the piezoelectric film layer 140 formed subsequently has good piezoelectric properties. The first buffer layer 135 can be used as an adhesion layer between the first electrode 130 and the piezoelectric film layer 140 to prevent the piezoelectric film layer 140 from peeling off from the first electrode 130. At the same time, the first buffer layer 135 can also be used as a barrier layer to prevent the material for forming the piezoelectric film layer 140 subsequently from diffusing into the first electrode 130.

[0056] S40: forming a piezoelectric film layer 140 on the first buffer layer 135. Exemplarily, the piezoelectric film layer 140 may be formed by a chemical solution deposition method, and the step further includes:

[0057] S41 : depositing a precursor solution of the piezoelectric film layer 140 on the first buffer layer 135 .

[0058] The precursor solution of the piezoelectric film layer 140 is deposited on the first buffer layer 135, or is coated by a spin coating process such as coating at a rotation speed of 2000 rpm-3000 rpm. According to the rotation speed and time, the precursor solution of the piezoelectric film layer 140 has a desired thickness. The material in the precursor solution of the piezoelectric film layer 140 can be lead zirconate titanate PZT (Pb (Zr, Ti) O3).

[0059] S42: Drying the precursor solution to form a thin film layer, for example, heating the precursor solution at 100° C. to 150° C. for about 1 minute to 10 minutes using a heating layer or an electric furnace. This step can burn and remove organic matter present during the formation of the piezoelectric film layer.

[0060] S43: calcining the thin film layer to form a piezoelectric film layer. For example, using RTA or other processes, heating at 500°C-800°C for about 1 minute to 10 minutes. By introducing oxygen or other atmospheres and sintering under pressure, a denser piezoelectric film layer can be obtained.

[0061] Repeat the above steps S41-4-S43 until a Figure 8 The piezoelectric film layer 140 shown has a desired thickness. For example, the thickness of the piezoelectric film layer 140 is 1 um-5 um.

[0062] In most cases, PZT materials are crystals composed of lead, zirconium, titanium, and oxygen. The crystal orientation of PZT materials has a great influence on piezoelectric properties. In order to show the piezoelectric effect, PZT needs to form a perovskite-type single-phase structure. The ideal perovskite structure is a cubic lattice. The vertices (A position) of the cubic lattice can be metals such as lead (Pb), the body center (B position) can be metals such as zirconium (Zr) and titanium (Ti), and the face center (C position) can be oxygen (O), thus forming an ABO3 crystal. Crystals with perovskite structure also include tetragonal, orthorhombic, and rhombohedral symmetric crystals that are deformed from cubic crystals. This crystal structure has good piezoelectric properties.

[0063] In this embodiment, in order to make the PZT material in the piezoelectric film layer have a perovskite-type single-phase structure, the crystal structure of the material in the first electrode 130 is firstly made similar to the above-mentioned perovskite-type single-phase structure through the aforementioned manufacturing process, and then the first buffer layer 135 replicates the crystal orientation of the first electrode 130, and the crystal phase of the piezoelectric film layer 140 using the PZT material also replicates the crystal orientation of the first buffer layer 135, so that the PZT material in the piezoelectric film layer 140 has a perovskite-type single-phase structure, that is, the crystal orientation in the piezoelectric film layer 140 is also <100> , the piezoelectric film layer 140 is lattice-matched with the first electrode 130, so that the piezoelectric film layer 140 of this crystal orientation has good piezoelectric properties, that is, it has a higher piezoelectric constant and a lower dielectric constant. By using the inverse piezoelectric effect, under the action of the electric field, the piezoelectric film layer 140 is deformed, thereby being able to convert electrical energy into mechanical energy to realize various functions of the actuator.

[0064] S45 : forming a second buffer layer 145 on the piezoelectric film layer 140 .

[0065] In this embodiment, if Fig. 9 The schematic diagram of the structure of the piezoelectric element shown in the figure shows that a second buffer layer 145 is formed on the piezoelectric film layer 140 by a sputtering process, a chemical solution deposition process or other suitable processes, and the material forming the second buffer layer 145 includes one or more of the following combinations: strontium ruthenate (SRO), lead lanthanum titanate ((Pb, La)TiO3), and lanthanum nickelate (LaNiO3). The second buffer layer 145 can be used as an adhesion layer between the piezoelectric film layer 140 and the second electrode 150 to prevent the piezoelectric film layer 140 from peeling off from the second electrode 150. At the same time, the second buffer layer 145 can also be used as a barrier layer to prevent the material forming the piezoelectric film layer 140 from diffusing into the second electrode 150.

[0066] It is understandable that the materials of the first buffer layer 135 and the second buffer layer 145 may be the same or different, and this embodiment of the present application does not limit this.

[0067] S50: forming a second electrode 150 on the second buffer layer 145.

[0068] In this embodiment, if Fig.10 The schematic diagram of the structure of the piezoelectric element shown in the figure can form the second electrode 150 on the second buffer layer 145 by a sputtering process or an electron evaporation process. The material of the second electrode 150 can be a polysilicon material or a metal material, and the metal material can include one or more of the following combinations: Pt, AU, copper (AU), aluminum (Al). It can be understood that since the material of the second electrode 150 does not need to be lattice matched with the material of the vibration layer 120, the material of the second electrode 150 in the embodiment of the present application can also be other conductive materials.

[0069] S55 : patterning the first electrode 130 , the first buffer layer 135 , the piezoelectric film layer 140 , the second buffer layer 145 and the second electrode 150 to form patterned first electrodes 130 , first buffer layers 135 , piezoelectric film layers 140 , second buffer layers 145 and second electrodes 150 .

[0070] In this embodiment, if Fig.11 The schematic diagram of the structure of the piezoelectric element shown in the figure can remove part of the first electrode 130, the first buffer layer 135, the piezoelectric film layer 140, the second buffer layer 145 and the second electrode 150 by a patterning process. The patterning process includes a photolithography process and an etching process. The photolithography process includes photoresist coating (e.g., spin coating), soft baking, mask alignment, exposure, post-exposure baking, developing photoresist, rinsing and drying (e.g., hard baking). The etching process includes a dry etching process or a wet etching process.

[0071] It should be noted that, when the first electrode 130, the first buffer layer 135, the piezoelectric film layer 140, the second buffer layer 145 and the second electrode 150 are patterned, the structure farther away from the substrate 101 contacts the etching medium earlier, for example, the second electrode 150 contacts the etching medium earlier than the second buffer layer 145 contacts the etching medium. Therefore, the patterned first electrode 130, the first buffer layer 135, the piezoelectric film layer 140, the second buffer layer 145 and the second electrode 150 have a width that increases from top to bottom.

[0072] Finally, S60 : forming a cavity 104 penetrating the substrate 101 on the substrate 101 . Specifically, the substrate 101 is etched from a side of the substrate 101 away from the vibration layer 120 , so as to form the cavity 104 penetrating the substrate on the substrate 101 .

[0073] In some embodiments, Fig.12 The schematic diagram of the structure of the piezoelectric element shown in the figure shows that the substrate 101 is etched by a dry etching process, and the vibration layer 120 is used as an etching stop layer during the etching process, that is, when the etching process reaches the vibration layer 120, since the vibration layer 120 reacts slowly or does not react with the etching medium, the vibration layer 120 can effectively prevent the etching from continuing, thereby controlling the etching depth and forming a cavity 104 that penetrates the substrate 101. The dry etching process uses an etching gas as an etching medium, such as carbon tetrafluoride (CF4), argon (Ar), nitrogen trifluoride (NF3), chlorine (Cl2), helium (He), hydrogen bromide (HBr), oxygen (O2), nitrogen (N2), fluoromethane (CH3F), methane (CH4), difluoromethane (CH2F2) or a combination thereof.

[0074] It should be noted that the above embodiments are only specific examples for better understanding the technical methods of the embodiments of the present application, and are not intended to be the sole limitation of the embodiments of the present application. According to the manufacturing method provided in the embodiments of the present application, the order of the various parts of the piezoelectric element can be appropriately adjusted, or increased or decreased according to actual conditions, or combined with other manufacturing process flows of the piezoelectric element to form a corresponding piezoelectric element.

[0075] In a specific example, the piezoelectric element includes a stacked substrate 101, a vibration layer 120, a first electrode 130, a first buffer layer 135, a piezoelectric film layer 140, a second buffer layer 145 and a second electrode 150. The substrate 101 is a single crystal silicon substrate, and a cavity 104 is provided in the substrate 101 that penetrates the substrate 101, and the cavity provides a vibration space for the vibration layer 120. The thickness of the vibration layer 120 is 1000nm. A voltage can be applied to the first electrode 130 and the second electrode 150 to form an electric field between the first electrode 130 and the second electrode 150. Since the electric field will cause the electric dipole moment of the piezoelectric material in the piezoelectric film layer to be redirected, the piezoelectric film layer 140 will generate strain or displacement under the action of the electric field, thereby converting electrical energy into mechanical energy.

[0076] Table 1 below shows a comparison of the dielectric properties of the piezoelectric element in this embodiment and the piezoelectric element provided in the aforementioned embodiment, wherein piezoelectric element 1 is the piezoelectric element in the aforementioned embodiment using an SOI substrate and a third buffer layer 115 with a thickness of 60 nm, and piezoelectric element 2 is the piezoelectric element provided in this embodiment with a vibration layer with a thickness of 1000 nm.

[0077] Table 1

[0078] ZrO2 thickness [nm] Piezoelectric constant d31[pm / V] Relative dielectric constant εr Piezoelectric element 1 60 243 960 Piezoelectric element 2 1000 242 985

[0079] It can be understood that the larger the piezoelectric constant, the stronger the strain effect of the piezoelectric element under the vertical electric field, that is, the more significant the piezoelectric effect. The relative dielectric constant can affect the capacitance value of the piezoelectric element, the electric field distribution of the dielectric material, and the propagation speed of electromagnetic waves in the medium. The larger the relative dielectric constant εr, the stronger the response of the piezoelectric element to the electric field, and the larger the capacitance value of the piezoelectric element. According to Table 1, the piezoelectric constant d31 of the piezoelectric element provided in this embodiment is 242pm / V, and the relative dielectric constant εr is 985. The piezoelectric constant d31 of the piezoelectric element using the SOI substrate and the third buffer layer 115 with a thickness of 60nm in the aforementioned embodiment is 243pm / V, and the relative dielectric constant εr is 960. Therefore, the piezoelectric element 2 provided in the embodiment of the present application and the piezoelectric element 1 in the aforementioned embodiment both have good piezoelectric performance. However, since the vibration layer 120 of a preset thickness can be directly formed in this embodiment, there is no need to use a grinding process for the vibration layer 120, so the film thickness error of the vibration layer is small, thereby improving the working accuracy of the piezoelectric element. At the same time, the use of a single crystal silicon substrate further reduces the cost.

[0080] The present application also provides an actuator 300, see Fig.13 , the actuator 300 includes a driving circuit 200 and the piezoelectric element 100 provided in the above embodiment. The driving circuit 200 and the piezoelectric element 100 are electrically connected. A voltage can be applied to the first electrode and the second electrode in the piezoelectric element 100 through the driving circuit 200. The applied voltage can be a constant DC voltage or an AC voltage, which is not limited in the embodiment of the present application. The voltage applied to the first electrode and the second electrode in the piezoelectric element 100 is used to form an electric field between the first electrode and the second electrode. Under the action of the electric field, the piezoelectric element 100 converts electrical energy into mechanical energy, so that the actuator 300 generates a mechanical displacement or force output.

[0081] It is understandable that the actuator 300 may also include other devices, such as a processor, which can detect the mechanical displacement or force output by the actuator and adjust the voltage applied by the drive circuit 200 to the first electrode and the second electrode to achieve the desired movement or force control.

[0082] The present application embodiment provides another electronic device 500. Fig.14As shown, the electronic device 500 may include the actuator 300 and the printed circuit board (PCB) 400 provided in the above embodiment. The electronic device 500 may include electronic products such as MEMS micromirrors, MEMS microphones, MEMS speakers, micro pumps, inkjet heads, ultrasonic sensors, etc. that require piezoelectric elements with high driving voltage and large deformation (displacement). The specific form of the above electronic device 500 is not particularly limited in the embodiment of the present application.

[0083] Another embodiment of the present application also provides a non-transitory computer-readable storage medium for use with a computer, the computer having software for creating and manufacturing the above-mentioned piezoelectric element, and one or more computer-readable data structures are stored on the computer-readable storage medium, and the one or more computer-readable data structures have control data for manufacturing the piezoelectric element provided in any one of the diagrams provided above, such as photoresist layer data.

[0084] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A piezoelectric element, characterized in that: The method comprises: a substrate, wherein the substrate comprises a cavity penetrating the substrate; A vibration layer is provided on the substrate, and the vibration layer covers the cavity; A first electrode, a piezoelectric film layer and a second electrode are stacked on the vibration layer, and the first electrode is lattice matched with the vibration layer.

2. The piezoelectric element according to claim 1, wherein The thickness of the vibration layer is 200nm-8000nm.

3. The piezoelectric element according to claim 1 or 2, characterized in that: The material of the vibration layer includes at least one or more of the following combinations: zirconium oxide, yttrium stabilized zirconium oxide, hafnium oxide, and hafnium zirconium oxide.

4. The piezoelectric element according to any one of claims 1 to 3, characterized in that: The material of the substrate includes at least one or more of the following combinations: silicon, germanium, silicon carbide, gallium arsenide, indium arsenide, and indium phosphide.

5. The piezoelectric element according to any one of claims 1 to 4, characterized in that: A first buffer layer is further arranged between the first electrode and the piezoelectric film layer.

6. The piezoelectric element according to any one of claims 1 to 5, characterized in that: A second buffer layer is further arranged between the piezoelectric film layer and the second electrode.

7. The piezoelectric element according to any one of claims 1 to 6, characterized in that: The first electrode and the piezoelectric film layer are lattice matched.

8. A method for manufacturing a piezoelectric element, characterized in that: include: forming a substrate; forming a vibration layer covering the substrate; forming a first electrode on the vibration layer, wherein the first electrode is lattice matched with the vibration layer; forming a piezoelectric film layer on the first electrode; forming a second electrode on the piezoelectric film layer; A cavity is formed on the substrate and penetrates the substrate.

9. The method according to claim 8, characterized in that Forming a cavity on the substrate and penetrating the substrate, comprising: The substrate is etched from a side of the substrate away from the vibration layer to form a cavity penetrating the substrate, and the vibration layer is used as an etching stop layer.

10. The method according to claim 8 or 9, characterized in that: Before forming the piezoelectric film layer, the manufacturing method further comprises: A first buffer layer is formed on the first electrode.

11. The method according to any one of claims 8 to 10, characterized in that: Before forming the second electrode, the method further includes: A second buffer layer is formed on the piezoelectric film layer.

12. The method according to any one of claims 8 to 11, characterized in that Forming the piezoelectric film layer comprises: Depositing a precursor solution of the piezoelectric film layer on the first electrode, and drying the precursor solution to form a thin film layer; The thin film layer is calcined to form the piezoelectric film layer.

13. An actuator, characterized in that: It comprises a driving circuit and a piezoelectric element as described in any one of claims 1 to 7, wherein a first end of the driving circuit is electrically connected to a first electrode of the piezoelectric element; and a second end of the driving circuit is electrically connected to a second electrode of the piezoelectric element.

14. An electronic device, characterized in that: The invention comprises a printed circuit layer and the actuator as claimed in claim 13, wherein the printed circuit layer is electrically connected to the actuator.

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