Piezoelectric device and method of forming the same

Abstract

The present invention provides a piezoelectric device comprising a substrate, a metal-insulator-metal (MIM) element, a hydrogen barrier layer, a passivation layer, a first contact terminal, and a second contact terminal. The MIM element is disposed on the substrate. The hydrogen barrier layer is disposed on the MIM element. The passivation layer covers the hydrogen barrier layer and the MIM element. The first contact terminal is electrically connected to the MIM element. The second contact terminal is electrically connected to the MIM element.

Description

Technical Field

[0001] Embodiments of the present invention relate to a piezoelectric device and a method for forming the same. Background Art

[0002] Piezoelectric devices are used in various fields and global demand for piezoelectric devices has become strong today. Summary of the Invention

[0003] According to an embodiment of the present invention, a piezoelectric device includes a substrate, a metal-insulator-metal (MIM) element, a hydrogen barrier layer, a passivation layer, a first contact terminal, and a second contact terminal. The MIM element is disposed on the substrate. The hydrogen barrier layer is disposed on the MIM element. The passivation layer covers the hydrogen barrier layer and the MIM element. The first contact terminal is electrically connected to the MIM element. The second contact terminal is electrically connected to the MIM element.

[0004] According to an embodiment of the present invention, a piezoelectric device includes a substrate, a first electrode, a piezoelectric layer, a second electrode, a hydrogen barrier layer, a passivation layer, a first contact terminal, and a second contact terminal. The first electrode is disposed on the substrate. The piezoelectric layer is disposed on the first electrode. The second electrode is disposed on the piezoelectric layer. The hydrogen barrier layer is disposed on the second electrode and above the substrate. The passivation layer covers the hydrogen barrier layer, the second electrode, the piezoelectric layer, and the first electrode. The first contact terminal is electrically connected to the first electrode. The second contact terminal is electrically connected to the second electrode.

[0005] According to an embodiment of the present invention, a method for forming a piezoelectric device includes: sequentially forming a first conductive layer, a piezoelectric material layer, and a second conductive layer on a substrate; forming a first hydrogen barrier material layer on the second conductive layer; patterning the first hydrogen barrier material layer to form a first hydrogen barrier layer; and forming a passivation layer to cover the first hydrogen barrier layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Various aspects of the present disclosure will be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the critical dimensions of various features may be arbitrarily increased or decreased for clarity of discussion.

[0007] Figure 1 Schematic cross-sectional view showing a piezoelectric device according to some embodiments.

[0008] Figure 2 FIG. 1 is a schematic top view illustrating a piezoelectric device according to some embodiments.

[0009] Figures 3A to 3I To illustrate the formation of Figure 1 and Figure 2 Schematic cross-sectional views of various stages of the method of making a piezoelectric device.

[0010] Figure 4 is a schematic cross-sectional view illustrating a piezoelectric device according to an alternative embodiment.

[0011] Figure 5 is a schematic cross-sectional view illustrating a piezoelectric device according to an alternative embodiment.

[0012] Figure 6A and Figure 6B is a schematic diagram illustrating an exemplary application of a piezoelectric device according to some embodiments.

[0013] Explanation of Figure Numbers

[0014] 10, 20a, 20b, 1000: piezoelectric device;

[0015] 100: substrate;

[0016] 101: first electrode;

[0017] 101A: first metal pattern;

[0018] 102: piezoelectric layer;

[0019] 103: second electrode;

[0020] 103A: second metal pattern;

[0021] 104: hydrogen barrier layer;

[0022] 104a: first hydrogen barrier layer;

[0023] 104b: second hydrogen barrier layer;

[0024] 104c: third hydrogen barrier layer;

[0025] 105: passivation layer;

[0026] 106: first contact terminal;

[0027] 107: second contact terminal;

[0028] 108: first conductive layer;

[0029] 109: piezoelectric material layer;

[0030] 110: second conductive layer;

[0031] 111: first hydrogen barrier material layer;

[0032] 112: second hydrogen barrier material layer;

[0033] 113: a third hydrogen barrier material layer;

[0034] 2000: Glass carrier;

[0035] 2002: Transparent polymer;

[0036] 2004: Glass film;

[0037] A-A', B-B': line;

[0038] F: focus;

[0039] H1: first contact hole;

[0040] H2: second contact hole;

[0041] L: beam;

[0042] MIM: Metal-Insulator-Metal components;

[0043] P1, P2: contact parts;

[0044] PR1: first photoresist layer;

[0045] PR2: second photoresist layer;

[0046] PR3: third photoresist layer;

[0047] θ: angle. DETAILED DESCRIPTION

[0048] The following disclosure provides many different embodiments or examples for implementing the different features of the provided themes. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not intended to be restrictive. For example, in the following description, the formation of a first feature above or on a second feature may include an embodiment in which the first feature and the second feature are directly in contact with each other, and may also include an embodiment in which an additional feature may be formed between the first feature and the second feature so that the first feature and the second feature may not be in direct contact. In addition, the present disclosure may reuse reference numerals and / or letters in various examples. This repetition is for the purpose of simplicity and clarity and does not itself indicate the relationship between the various embodiments and / or configurations discussed.

[0049] Furthermore, for ease of description, spatially relative terms such as "below," "beneath," "lower," "on," "over," "overlying," "above," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the various 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 similarly accordingly.

[0050] Piezoelectric devices are devices that utilize the piezoelectric effect, including piezoelectric sensors, actuators, transducers, transformers, and motors. A piezoelectric device (such as an actuator) may include a piezoelectric layer stacked between a first electrode and a second electrode. When a voltage is applied, the electric field generated by the applied voltage will cause the piezoelectric layer to stretch or compress (i.e., deform) in a direction perpendicular to the piezoelectric layer. The deformation of the piezoelectric layer is converted into physical displacement. This physical displacement can be used to move or position targets in various mechanical and optical systems. The amount of physical displacement or movement depends roughly on the applied voltage and the piezoelectric coefficient of the piezoelectric layer (i.e., the efficiency of the piezoelectric material in converting electrical energy into mechanical energy). The performance of a piezoelectric device can be determined by the characteristics of the piezoelectric layer in the piezoelectric device. In order to improve the reliability of the piezoelectric device, it is better to reduce or minimize the amount of hydrogen ions present in the piezoelectric layer of the piezoelectric device.

[0051] During the manufacturing process, hydrogen ion treatment may be performed after the piezoelectric layer is formed, which may cause hydrogen ions to be contained in the piezoelectric layer and reduce the reliability of the piezoelectric device. According to some embodiments, it is desirable to form a barrier material or shielding layer before performing the hydrogen ion treatment to prevent and hinder hydrogen ions from entering the piezoelectric layer.

[0052] Figure 1 Schematic cross-sectional view showing a piezoelectric device according to some embodiments. Figure 2 FIG. 1 is a schematic top view illustrating a piezoelectric device according to some embodiments. Figure 2 It is along Figure 1 It should be noted that for simplicity, Figure 2 Some elements of the piezoelectric device 10 are omitted from illustration.

[0053] See Figure 1 and Figure 2The piezoelectric device 10 includes a substrate 100, a first electrode 101, a piezoelectric layer 102, a second electrode 103, a hydrogen barrier layer 104, a passivation layer 105, a first contact terminal 106, and a second contact terminal 107. In some embodiments, the first electrode 101 is disposed on the substrate 100, the piezoelectric layer 102 is disposed on the first electrode 101, the second electrode 103 is disposed on the piezoelectric layer 102, the hydrogen barrier layer 104 is disposed on the second electrode 103, the passivation layer 105 covers the hydrogen barrier layer 104, the second electrode 103, the piezoelectric layer 102, and the first electrode 101, the first contact terminal 106 is electrically connected to the first electrode 101, and the second contact terminal 107 is electrically connected to the second electrode 103.

[0054] exist Figure 1 and Figure 2 In the embodiment of the present invention, the first electrode 101, the piezoelectric layer 102 and the second electrode 103 are stacked in sequence on the substrate 100. In other words, the piezoelectric layer 102 is located between the first electrode 101 and the second electrode 103. In some embodiments, the first electrode 101 includes a first metal pattern 101A, and the second electrode 103 includes a second metal pattern 103A. In some embodiments, the material of the piezoelectric layer 102 includes a piezoelectric ceramic material such as lead zirconate titanate (PZT). Specifically, the stacked structure of the first electrode 101, the piezoelectric layer 102 and the second electrode 103 constitutes a metal-insulator-metal (MIM) element. That is, in some embodiments, the metal-insulator-metal (MIM) element is disposed on the substrate 100, the hydrogen barrier layer 104 is disposed on the metal-insulator-metal (MIM) element, the passivation layer 105 covers the hydrogen barrier layer 104 and the metal-insulator-metal (MIM) element, and the first contact terminal 106 and the second contact terminal 107 are electrically connected to the metal-insulator-metal (MIM) element.

[0055] Still see Figure 1 , from a top view, the first electrode 101 is designed to be a substantially annular electrode having a contact portion P1 protruding from the outline of the annular electrode, and the second electrode 103 is designed to be a substantially annular electrode having a contact portion P2 protruding from the outline of the annular electrode. However, the present disclosure is not limited thereto. In some alternative embodiments, from a top view, the shape of the pattern of the first electrode 101 and the second electrode 103 may be an elliptical, quadrilateral, hexagonal or polygonal or any suitable shape. In addition, the shape of the pattern of the piezoelectric layer 102 is designed to be annular (corresponding to the shape of the top electrode 101 and the bottom electrode 103). According to Figure 1In the top view shown in FIG, the first electrode 101, the piezoelectric layer 102, and the second electrode 103 are arranged in concentric circles. However, the present disclosure is not limited thereto. In some alternative embodiments, the pattern of the piezoelectric layer 102 can be designed to be a polygon or any other suitable shape when viewed from above. In other alternative embodiments, the first electrode 101, the piezoelectric layer 102, and the second electrode 103 can be arranged in non-concentric circles.

[0056] Continue to read Figure 1 , according to the top view, the span of the first electrode 101 is greater than the span of the piezoelectric layer 102, and the span of the piezoelectric layer 102 is greater than the span of the second electrode 103. From another point of view, Figure 2 As shown in the cross section of FIG, the first electrode 101, the piezoelectric layer 102 and the second electrode 103 form a staircase shaped stacked-structure.

[0057] In some embodiments, first contact terminal 106 is electrically connected to first electrode 101 via first contact hole H1 in passivation layer 105 and hydrogen barrier layer 104, and second contact terminal 107 is electrically connected to second electrode 103 via second contact hole H2 in passivation layer 105 and hydrogen barrier layer 104. Specifically, first contact terminal 106 is electrically connected to contact portion P1 of first electrode 101, and second contact terminal 107 is electrically connected to contact portion P2 of second electrode 103. In some embodiments, both first contact terminal 106 and second contact terminal 107 can function as external input / output terminals for piezoelectric device 10. When a voltage is applied between first contact terminal 106 and second contact terminal 107, the same voltage is also applied between first electrode 101 and second electrode 103. The electric field generated by the applied voltage can cause piezoelectric layer 102 to stretch or compress in a direction perpendicular to the surface of substrate 100. The stretching and compression of piezoelectric layer 102 is converted into physical displacement used to control a mechanical or optical system.

[0058] In some embodiments, the hydrogen barrier layer 104 includes a first hydrogen barrier layer 104a, a second hydrogen barrier layer 104b, and a third hydrogen barrier layer 104c. That is, in some embodiments, the hydrogen barrier layer 104 is a multilayer structure. Specifically, Figure 2As shown in FIG, first hydrogen barrier layer 104a covers and contacts the top surface of second electrode 103, second hydrogen barrier layer 104b covers first hydrogen barrier layer 104a and contacts the top surface of piezoelectric layer 102, and third hydrogen barrier layer 104c covers second hydrogen barrier layer 104b and contacts the top surface of first electrode 101. In other words, during the manufacturing process of piezoelectric device 10, hydrogen barrier layer 104 covers and protects the outermost top surface of the metal-insulator-metal (MIM) element. Because hydrogen barrier layer 104 covers and protects the outermost top surface of the metal-insulator-metal (MIM) element, hydrogen barrier layer 104 can prevent hydrogen ions in the photoresist layer from penetrating into the metal-insulator-metal (MIM) element. As a result, no or very few hydrogen ions are contained in piezoelectric layer 102 of piezoelectric device 10, and the piezoelectric properties of piezoelectric layer 102 are maintained. In other words, hydrogen barrier layer 104 can achieve improved reliability of piezoelectric device 10.

[0059] The method of forming the piezoelectric device 10 will be described below with reference to Figures 3A to 3I Detailed description. Figures 3A to 3I To illustrate the formation of Figure 1 and Figure 2 Schematic cross-sectional views of various stages of the method of making a piezoelectric device.

[0060] refer to Figure 3A , providing a substrate 100. In some embodiments, the material of the substrate 100 may include, for example, silicon, glass, silicon dioxide, aluminum oxide, or the like. Figure 3A, a first conductive layer 108, a piezoelectric material layer 109, a second conductive layer 110, and a first hydrogen barrier material layer 111 are sequentially formed on the substrate 100. In other words, the piezoelectric material layer 109 is located between the first conductive layer 108 and the second conductive layer 110, and the first hydrogen barrier material layer 111 is located on the second conductive layer 110. In some embodiments, the materials of the first conductive layer 108 and the second conductive layer 110 may each include, but are not limited to, molybdenum (Mo), titanium nitride (TiN), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), combinations thereof, or the like. In some embodiments, the material of the first conductive layer 108 is the same as the material of the second conductive layer 110. In some alternative embodiments, the material of the first conductive layer 108 is different from the material of the second conductive layer 110. In some embodiments, the first conductive layer 108 and the second conductive layer 110 may each have a thickness ranging from about 200 angstroms to about 2000 angstroms. In some embodiments, the first conductive layer 108 and the second conductive layer 110 may each be formed by a deposition process, such as chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD).

[0061] In some embodiments, the material of the piezoelectric material layer 109 may include, but is not limited to, aluminum nitride (AlN), lead zirconate titanate (PZT), gallium orthophosphate (GaPO4), lanthanum gallium silicate (langasite, La3Ga5SiO 14 ), barium titanate (BaTiO3), potassium niobate (KNbO3), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), sodium tungstate (Na2WO3), zinc oxide (ZnO), combinations thereof, or the like. In some embodiments, the piezoelectric material layer 109 may have a thickness ranging from approximately 2,000 angstroms to 20,000 angstroms. In some embodiments, the piezoelectric material layer 109 may be formed by PVD or a sol-gel process.

[0062] In some embodiments, the material of the first hydrogen barrier material layer 111 may include a metal oxide. Examples of metal oxides may include aluminum oxide (Al2O3), titanium dioxide (TiO2), iron oxide (Fe2O3), zirconium dioxide (ZrO2), zinc oxide (ZnO), copper oxide (CuO), or tantalum pentoxide (Ta2O5). In some embodiments, the first hydrogen barrier material layer 111 may have a thickness greater than 200 angstroms. Specifically, due to its thickness greater than 200 angstroms, the first hydrogen barrier layer 104a formed by the first hydrogen barrier material layer 111 has excellent hydrogen ion barrier capabilities. In some embodiments, the first hydrogen barrier material layer 111 may be formed by a deposition process, such as ALD or PVD. Specifically, the first hydrogen barrier material layer 111 is formed by ALD, and thus the first hydrogen barrier material layer 111 is sufficiently dense so that the first hydrogen barrier layer 104a formed by the first hydrogen barrier material layer 111 has excellent hydrogen ion barrier capabilities. In addition, the first hydrogen barrier material layer 111 is formed by PVD, and thus no additional hydrogen ions are present from the first hydrogen barrier material layer 111 .

[0063] See Figure 3B , a first photolithography step is performed to form a first photoresist layer PR1 on the first hydrogen barrier material layer 111. In other words, the first hydrogen barrier material layer 111 is located between the first photoresist layer PR1 and the second conductive layer 110. In some embodiments, the first photolithography step for forming the first photoresist layer PR1 may include the following steps: coating a photoresist material on the first hydrogen barrier material layer 111, exposing the photoresist material using a photolithography mask (or photomask), and developing the exposed photoresist material. In some embodiments, the first photoresist layer PR1 includes a positive photoresist material that is photo-solubilized when exposed to light. In some alternative embodiments, the first photoresist layer PR1 includes a negative photoresist material.

[0064] See Figure 3B and Figure 3C, a first etching step is performed on the first hydrogen barrier material layer 111 and the second conductive layer 110 using the first photoresist layer PR1 as an etching mask, so that the first hydrogen barrier material layer 111 and the second conductive layer 110 are etched to form the first hydrogen barrier layer 104a and the second electrode 103, and the portion of the piezoelectric material layer 109 not covered by the first hydrogen barrier layer 104a and the second electrode 103 is exposed. In other words, the first hydrogen barrier material layer 111 and the second conductive layer 110 are patterned simultaneously using the same mask to form the first hydrogen barrier layer 104a and the second electrode 103. That is, the first hydrogen barrier layer 104a and the second electrode 103 have substantially the same layout. In some embodiments, the first etching step is an ion beam etching step for patterning the first hydrogen barrier material layer 111 and the second conductive layer 110 in a single patterning process. In some embodiments, during the ion beam etching step, there is substantially no etching selectivity between the first hydrogen barrier material layer 111 and the second conductive layer 110 , which means that the ratio of the etching rate of the material of the first hydrogen barrier material layer 111 to the material of the second conductive layer 110 is substantially 1. It should be noted that since the first hydrogen barrier material layer 111 is formed between the first photoresist layer PR1 and the second conductive layer 110 , during the first etching step, the first hydrogen barrier layer 104 a helps prevent hydrogen ions in the first photoresist layer PR1 from penetrating into the second electrode 103 .

[0065] like Figure 3C As shown in FIG, the first hydrogen barrier layer 104a is located between the first photoresist layer PR1 and the second electrode 103. From another perspective, the first hydrogen barrier layer 104a is formed to physically contact the second electrode 103 at the top surface of the second electrode 103. The details of the first hydrogen barrier layer 104a and the second electrode 103 have been described above and will not be repeated here.

[0066] See Figure 3C and Figure 3D After forming the first hydrogen barrier layer 104a and the second electrode 103, the first photoresist layer PR1 is removed. In some embodiments, the first photoresist layer PR1 can be removed by a stripping process, such as a dry stripping process, a wet stripping process, or a combination thereof. As mentioned above, since the first hydrogen barrier layer 104a is located between the first photoresist layer PR1 and the second electrode 103, during the stripping process of the first photoresist layer PR1, the first hydrogen barrier layer 104a helps prevent hydrogen ions in the first photoresist layer PR1 from penetrating into the second electrode 103.

[0067] Still see Figure 3D, the second hydrogen barrier material layer 112 is formed on the first hydrogen barrier layer 104a and the second electrode 103. In addition, the second hydrogen barrier material layer 112 is formed on the portion of the piezoelectric material layer 109 not covered by the first hydrogen barrier layer 104a and the second electrode 103. In some embodiments, the second hydrogen barrier material layer 112 is a conformal layer. In detail, the second hydrogen barrier material layer 112 conformally and completely covers the top surface and sidewalls of the first hydrogen barrier layer 104a, the sidewalls of the second electrode 103, and the portion of the piezoelectric material layer 109 not covered by the first hydrogen barrier layer 104a and the second electrode 103. However, the present disclosure is not limited to this. In some alternative embodiments, the second hydrogen barrier material layer 112 is not a conformal layer.

[0068] In some embodiments, the material of the second hydrogen barrier material layer 112 may include a metal oxide. Examples of metal oxides may include Al2O3, TiO2, Fe2O3, ZrO2, ZnO, CuO, or Ta2O5. In some embodiments, the material of the second hydrogen barrier material layer 112 is the same as the material of the first hydrogen barrier material layer 111. In some alternative embodiments, the material of the second hydrogen barrier material layer 112 is different from the material of the first hydrogen barrier material layer 111.

[0069] In some embodiments, the second hydrogen barrier material layer 112 may have a thickness greater than 200 angstroms. Specifically, due to its thickness greater than 200 angstroms, the second hydrogen barrier layer 104b formed by the second hydrogen barrier material layer 112 has excellent hydrogen ion blocking capabilities. In some embodiments, the thickness of the second hydrogen barrier material layer 112 is the same as the thickness of the first hydrogen barrier material layer 111. In some alternative embodiments, the thickness of the second hydrogen barrier material layer 112 is different from the thickness of the first hydrogen barrier material layer 111.

[0070] In some embodiments, the second hydrogen barrier material layer 112 can be formed by a deposition process, such as ALD or PVD. Specifically, the second hydrogen barrier material layer 112 is formed by ALD, and thus the second hydrogen barrier material layer 112 is sufficiently dense so that the second hydrogen barrier layer 104b formed by the second hydrogen barrier material layer 112 has good hydrogen ion barrier capability. In addition, the second hydrogen barrier material layer 112 is formed by PVD, and thus no additional hydrogen ions are generated from the second hydrogen barrier material layer 112.

[0071] Continue to read Figure 3D, a second photolithography step is performed to form a second photoresist layer PR2 on the second hydrogen barrier material layer 112. In other words, the second hydrogen barrier material layer 112 is located between the second photoresist layer PR2 and the second electrode 103, and between the second photoresist layer PR2 and the piezoelectric material layer 109. In some embodiments, the second photolithography step for forming the second photoresist layer PR2 may include the following steps: coating a photoresist material on the second hydrogen barrier material layer 112, exposing the photoresist material with a photolithography mask (or photomask), and developing the exposed photoresist material. In some embodiments, the second photoresist layer PR2 includes a positive photoresist material that is photodissolved when exposed to light. In some alternative embodiments, the second photoresist layer PR2 includes a negative photoresist material.

[0072] See Figure 3D and Figure 3E , a second etching step is performed on the second hydrogen barrier material layer 112 and the piezoelectric material layer 109 using the second photoresist layer PR2 as an etching mask, so that the second hydrogen barrier material layer 112 and the piezoelectric material layer 109 are etched to form the second hydrogen barrier layer 104b and the piezoelectric layer 102, and the portion of the first conductive layer 108 not covered by the second hydrogen barrier layer 104b and the piezoelectric layer 102 is exposed. In other words, the second hydrogen barrier material layer 112 and the piezoelectric material layer 109 are patterned simultaneously to form the second hydrogen barrier layer 104b and the piezoelectric layer 102 by using the same mask. That is, the second hydrogen barrier layer 104b and the piezoelectric layer 102 have substantially the same layout. In some embodiments, the second etching step is an ion beam etching step for patterning the second hydrogen barrier material layer 112 and the piezoelectric material layer 109 in a single patterning process. In detail, in some embodiments, during the ion beam etching step, there is substantially no etching selectivity between the second hydrogen barrier material layer 112 and the piezoelectric material layer 109, which means that the ratio of the etching rate of the material of the second hydrogen barrier material layer 112 to the material of the piezoelectric material layer 109 is substantially 1. It should be noted that since the second hydrogen barrier material layer 112 is formed between the second photoresist layer PR2 and the second electrode 103, and between the second photoresist layer PR2 and the piezoelectric material layer 109, during the second etching step, the second hydrogen barrier layer 104b can inhibit hydrogen ions in the second photoresist layer PR2 from penetrating into the second electrode 103 and the piezoelectric layer 102.

[0073] like Figure 3EAs shown in FIG, the second hydrogen barrier layer 104b is located between the second photoresist layer PR2 and the first hydrogen barrier layer 104a, between the second photoresist layer PR2 and the second electrode 103, and between the second photoresist layer PR2 and the piezoelectric layer 102. Specifically, the second hydrogen barrier layer 104b is formed to physically contact the first hydrogen barrier layer 104a at the top surface and sidewalls of the first hydrogen barrier layer 104a, to physically contact the second electrode 103 at the sidewalls of the second electrode 103, and to physically contact the piezoelectric layer 102 at the top surface of the piezoelectric layer 102. In addition, as shown in FIG. Figure 3E As shown in the cross section of FIG, the sidewall of the piezoelectric layer 102 is laterally displaced from the sidewall of the second electrode 103. In detail, the sidewall of the piezoelectric layer 102 is laterally displaced outward from the sidewall of the second electrode 103. In other words, Figure 3E In the cross section of , the width of the piezoelectric layer 102 is greater than the width of the second electrode 103. Specifically, as Figure 3E As shown in the cross section of FIG, the second electrode 103 and the piezoelectric layer 102 form a stacked structure having stepped sidewalls on both sides. Figure 3E As shown in FIG, the second electrode 103 covers a portion of the piezoelectric layer 102, and thus the top surface of the piezoelectric layer 102 in contact with the second hydrogen barrier layer 104b is not covered by the second electrode 103. From another point of view, according to Figure 1 In the top view, the boundary of the second electrode 103 is within the boundary of the piezoelectric layer 102. Other details of the second hydrogen barrier layer 104b and the piezoelectric layer 102 have been described above and will not be repeated here.

[0074] See Figure 3E and Figure 3F After forming the second hydrogen barrier layer 104b and the piezoelectric layer 102, the second photoresist layer PR2 is removed. In some embodiments, the second photoresist layer PR2 can be removed by a stripping process, such as a dry stripping process, a wet stripping process, or a combination thereof. As mentioned above, since the second hydrogen barrier layer 104b is located between the second photoresist layer PR2 and the second electrode 103 and between the second photoresist layer PR2 and the piezoelectric layer 102, during the stripping process of the second photoresist layer PR2, the second hydrogen barrier layer 104b helps prevent hydrogen ions in the second photoresist layer PR2 from penetrating into the second electrode 103 and the piezoelectric layer 102.

[0075] Still see Figure 3F, the third hydrogen barrier material layer 113 is formed on the second hydrogen barrier layer 104b and the piezoelectric layer 102. In addition, the third hydrogen barrier material layer 113 is formed on the portion of the first conductive layer 108 not covered by the second hydrogen barrier layer 104b and the piezoelectric layer 102. In some embodiments, the third hydrogen barrier material layer 113 is a conformal layer. In detail, the third hydrogen barrier material layer 113 conformally and completely covers the top surface and sidewalls of the second hydrogen barrier layer 104b, the sidewalls of the piezoelectric layer 102, and the portion of the first conductive layer 108 not covered by the second hydrogen barrier layer 104b and the piezoelectric layer 102. However, the present disclosure is not limited to this. In some alternative embodiments, the third hydrogen barrier material layer 113 is not a conformal layer.

[0076] In some embodiments, the material of the third hydrogen barrier material layer 113 may include a metal oxide. Examples of metal oxides may include Al2O3, TiO2, Fe2O3, ZrO2, ZnO, CuO, or Ta2O5. In some embodiments, the material of the third hydrogen barrier material layer 113 is the same as the material of the second hydrogen barrier material layer 112 and the material of the first hydrogen barrier material layer 111. In some alternative embodiments, the material of the third hydrogen barrier material layer 113 is different from at least one of the material of the second hydrogen barrier material layer 112 and the material of the first hydrogen barrier material layer 111. In other words, the material of the third hydrogen barrier material layer 113 is the same as or different from the material of the second hydrogen barrier material layer 112, and the material of the third hydrogen barrier material layer 113 is the same as or different from the material of the first hydrogen barrier material layer 111.

[0077] In some embodiments, the third hydrogen barrier material layer 113 may have a thickness greater than 200 angstroms. In detail, due to having a thickness greater than 200 angstroms, the third hydrogen barrier layer 104c formed by the third hydrogen barrier material layer 113 has good blocking ability against hydrogen ions. In some embodiments, the thickness of the third hydrogen barrier material layer 113 is the same as the thickness of the second hydrogen barrier material layer 112 and the thickness of the first hydrogen barrier material layer 111. In some alternative embodiments, the thickness of the third hydrogen barrier material layer 113 is different from at least one of the thickness of the second hydrogen barrier material layer 112 and the thickness of the first hydrogen barrier material layer 111. That is, the thickness of the third hydrogen barrier material layer 113 is the same as or different from the thickness of the second hydrogen barrier material layer 112, and the thickness of the third hydrogen barrier material layer 113 is the same as or different from the thickness of the first hydrogen barrier material layer 111.

[0078] In some embodiments, the third hydrogen barrier material layer 113 can be formed by a deposition process, such as ALD or PVD. Specifically, the third hydrogen barrier material layer 113 is formed by ALD, and thus the third hydrogen barrier material layer 113 is sufficiently dense so that the third hydrogen barrier layer 104c formed by the third hydrogen barrier material layer 113 has good hydrogen ion barrier capability. In addition, the third hydrogen barrier material layer 113 is formed by PVD, and thus no additional hydrogen ions are generated from the third hydrogen barrier material layer 113.

[0079] Continue to read Figure 3F , a third photolithography step is performed to form a third photoresist layer PR3 on the third hydrogen barrier material layer 113. In other words, the third hydrogen barrier material layer 113 is located between the third photoresist layer PR3 and the piezoelectric layer 102 and between the third photoresist layer PR3 and the first conductive layer 108. In some embodiments, the third photolithography step for forming the third photoresist layer PR3 may include the following steps: coating a photoresist material on the third hydrogen barrier material layer 113, exposing the photoresist material using a photolithography mask (or photomask), and developing the exposed photoresist material. In some embodiments, the third photoresist layer PR3 includes a positive photoresist material that is photodissolved when exposed to light. In some alternative embodiments, the third photoresist layer PR3 includes a negative photoresist material.

[0080] See Figure 3F and Figure 3G, a third etching step is performed on the third hydrogen barrier material layer 113 and the first conductive layer 108 using the third photoresist layer PR3 as an etching mask, so that the third hydrogen barrier material layer 113 and the first conductive layer 108 are etched to form the third hydrogen barrier layer 104c and the first electrode 101, and the portion of the substrate 100 not covered by the third hydrogen barrier layer 104c and the first electrode 101 is exposed. In other words, the third hydrogen barrier material layer 113 and the first conductive layer 108 are patterned simultaneously using the same mask to form the third hydrogen barrier layer 104c and the first electrode 101. That is, the third hydrogen barrier layer 104c and the first electrode 101 have substantially the same layout. In some embodiments, the third etching step is an ion beam etching step for patterning the third hydrogen barrier material layer 113 and the first conductive layer 108 in a single patterning process. In detail, in some embodiments, during the ion beam etching step, there is substantially no etching selectivity between the third hydrogen barrier material layer 113 and the first conductive layer 108, which means that the ratio of the etching rate of the material of the third hydrogen barrier material layer 113 to the material of the first conductive layer 108 is substantially 1. It should be noted that since the third hydrogen barrier material layer 113 is formed between the third photoresist layer PR3 and the piezoelectric layer 102 and between the third photoresist layer PR3 and the first conductive layer 108, during the third etching step, the third hydrogen barrier layer 104c helps to prevent hydrogen ions in the third photoresist layer PR3 from penetrating into the piezoelectric layer 102 and the first electrode 101.

[0081] like Figure 3G As shown in FIG, the third hydrogen barrier layer 104c is located between the third photoresist layer PR3 and the second hydrogen barrier layer 104b, between the third photoresist layer PR3 and the piezoelectric layer 102, and between the third photoresist layer PR3 and the first electrode 101. Specifically, the third hydrogen barrier layer 104c is formed to physically contact the second hydrogen barrier layer 104b at the top surface and sidewalls of the second hydrogen barrier layer 104b, to physically contact the piezoelectric layer 102 at the sidewalls of the piezoelectric layer 102, and to physically contact the first electrode 101 at the top surface of the first electrode 101. In addition, as shown in FIG. Figure 3G As shown in the cross section of FIG, the sidewall of the first electrode 101 is laterally displaced from the sidewall of the piezoelectric layer 102. In detail, the sidewall of the first electrode 101 is laterally displaced outward from the sidewall of the piezoelectric layer 102. In other words, Figure 3G In the cross section of , the width of the first electrode 101 is greater than the width of the piezoelectric layer 102. Specifically, as Figure 3G As shown in the cross section of FIG, the piezoelectric layer 102 and the first electrode 101 form a stacked structure having stepped sidewalls on both sides. Figure 3GAs shown in FIG, the piezoelectric layer 102 covers a portion of the first electrode 101, and thus the top surface of the first electrode 101 in contact with the third hydrogen barrier layer 104c is not covered by the piezoelectric layer 102. From another point of view, as shown in FIG. Figure 1 In the top view, the boundary of the piezoelectric layer 102 is within the boundary of the first electrode 101. Other details of the third hydrogen barrier layer 104c and the first electrode 101 have been described above and will not be repeated here.

[0082] After the first electrode 101 is formed, the formation of the metal-insulator-metal element MIM including the first electrode 101, the piezoelectric layer 102, and the second electrode 103 is completed. In detail, as mentioned above, since the second electrode 103 and the piezoelectric layer 102 are formed to form a stacked structure having stepped sidewalls on both sides, and the piezoelectric layer 102 and the first electrode 101 are also formed to form a stacked structure having stepped sidewalls on both sides, the metal-insulator-metal element MIM including the first electrode 101, the piezoelectric layer 102, and the second electrode 103 has a stepped stacked structure, as shown in FIG. Figure 3G shown in a cross section.

[0083] In addition, after the third hydrogen barrier layer 104c is formed, the formation of the hydrogen barrier layer 104 including the first hydrogen barrier layer 104a, the second hydrogen barrier layer 104b and the third hydrogen barrier layer 104c is completed. Figure 3G As shown in FIG, the hydrogen barrier layer 104 covers and contacts the top surface of the second electrode 103, and the hydrogen barrier layer 104 contacts a portion of the top surface of the first electrode 101 and a portion of the top surface of the piezoelectric layer 102. Specifically, the hydrogen barrier layer 104 physically contacts the metal-insulator-metal element MIM at the top surface and sidewalls of the second electrode 103, at the sidewalls and a portion of the top surface of the piezoelectric layer 102, and at a portion of the top surface of the first electrode 101. Figure 3G As shown in the figure, the thickness of the hydrogen barrier layer 104 located on the top surface of the second electrode 103 and in contact therewith is greater than the thickness of the hydrogen barrier layer 104 located on the top surface of the piezoelectric layer 102 and in contact therewith, and the thickness of the hydrogen barrier layer 104 located on the top surface of the piezoelectric layer 102 and in contact therewith is greater than the thickness of the hydrogen barrier layer 104 located on the top surface of the first electrode 101 and in contact therewith.

[0084] See Figure 3G and Figure 3HAfter forming the third hydrogen barrier layer 104c and the first electrode 101, the third photoresist layer PR3 is removed. In some embodiments, the third photoresist layer PR3 can be removed by a stripping process, such as a dry stripping process, a wet stripping process, or a combination thereof. As mentioned above, since the third hydrogen barrier layer 104c is located between the third photoresist layer PR3 and the piezoelectric layer 102 and between the third photoresist layer PR3 and the first electrode 101, during the stripping process of the third photoresist layer PR3, the third hydrogen barrier layer 104c helps prevent hydrogen ions in the third photoresist layer PR3 from penetrating into the piezoelectric layer 102 and the first electrode 101.

[0085] Still see Figure 3H , forming a passivation layer 105 to cover the hydrogen barrier layer 104 and the metal-insulator-metal element MIM. In some embodiments, the passivation layer 105 can be formed by CVD, PVD, or any other suitable technique. In some embodiments, the material of the passivation layer 105 can be a dielectric material, such as silicon oxide, silicon nitride, silicon oxynitride, or a combination thereof. In some embodiments, the passivation layer 105 can have a thickness ranging from about 200 angstroms to about 2000 angstroms. The details of the passivation layer 105 have been described above and are not repeated here.

[0086] See Figure 3H and Figure 3I The passivation layer 105 and the hydrogen barrier layer 104 are patterned to form a first contact hole H1 and a second contact hole H2 for exposing the contact portion P1 of the first electrode 101 and the contact portion P2 of the second electrode 103. Figure 3I As shown in FIG, first contact hole H1 is formed in passivation layer 105 and third hydrogen barrier layer 104c, and second contact hole H2 is formed in passivation layer 105, first hydrogen barrier layer 104a, second hydrogen barrier layer 104b, and third hydrogen barrier layer 104c. In some embodiments, first contact hole H1 and second contact hole H2 can be formed by performing photolithography and etching processes.

[0087] Then, return to see Figure 2A first contact terminal 106 is formed on the passivation layer 105 to electrically connect to the first electrode 101 through a first contact hole H1, and a second contact terminal 107 is formed on the passivation layer 105 to electrically connect to the second electrode 103 through a second contact hole H2. Specifically, the first contact terminal 106 is formed to electrically connect to the contact portion P1 of the first electrode 101, and the second contact terminal 107 is formed to electrically connect to the contact portion P2 of the second electrode 103. In some embodiments, the materials of the first and second contact terminals 106 and 107 may each include, but are not limited to, silver (Ag), titanium (Ti), tantalum (Ta), ruthenium (Ru), aluminum (Al), copper (Cu), gold (Au), combinations thereof, or the like. This completes the fabrication of the piezoelectric device 10 according to some embodiments. The first and second contact terminals 106 and 107 provide input / output terminals for receiving a voltage to control the physical displacement of the piezoelectric device 10. The details of the first and second contact terminals 106 and 107 have been described above and are not further elaborated here.

[0088] exist Figures 3A to 3I In the above-mentioned embodiment illustrated in , since the corresponding hydrogen barrier material layer (i.e., the first hydrogen barrier material layer 111, the second hydrogen barrier material layer 112, the third hydrogen barrier material layer 113) has been formed before each photoresist layer (i.e., the first photoresist layer PR1, the second photoresist layer PR2, the third photoresist layer PR3) used as an etching mask for forming the metal-insulator-metal element MIM is formed, the hydrogen ions in the photoresist layer are prohibited from penetrating into the metal-insulator-metal element MIM by the corresponding hydrogen barrier material layer during the etching process and the stripping process. From another perspective, since hydrogen barrier layer 104 includes first hydrogen barrier layer 104a, second hydrogen barrier layer 104b, and third hydrogen barrier layer 104c, with first hydrogen barrier layer 104a formed to cover and contact the top surface of second electrode 103, second hydrogen barrier layer 104b formed to cover second electrode 103 and contact the top surface of piezoelectric layer 102, and third hydrogen barrier layer 104c formed to cover second electrode 103 and piezoelectric layer 102 and contact the top surface of first electrode 101, during the manufacture of piezoelectric device 10, each of first hydrogen barrier layer 104, second hydrogen barrier layer 104b, and third hydrogen barrier layer 104c helps prevent hydrogen ions from the photoresist layer from penetrating into the metal-insulator-metal (MIM) element during the manufacture of piezoelectric device 10. Based on the above discussion, it should be noted that due to the arrangement of hydrogen barrier layer 104, the number of hydrogen ions present in the metal-insulator-metal (MIM) element of piezoelectric device 10 is reduced, and the reliability of piezoelectric device 10 is improved.

[0089] When compared with a piezoelectric device without a hydrogen barrier layer, the number of hydrogen ions of the metal-insulator-metal element MIM included in the piezoelectric device is reduced by about 50% due to the arrangement of the hydrogen barrier layer.

[0090] Furthermore, during reliability testing under the same conditions, piezoelectric devices designed with at least one hydrogen barrier layer according to certain of the aforementioned embodiments had a near-zero failure rate, compared to a failure rate of greater than 50% for piezoelectric devices without a hydrogen barrier layer. Furthermore, piezoelectric devices designed with at least one hydrogen barrier layer according to certain of the aforementioned embodiments provided a higher breakdown voltage. When compared to piezoelectric devices without a hydrogen barrier layer, a breakdown voltage difference of 20 volts or greater was observed. Based on the above results, the performance and reliability of piezoelectric devices can be significantly improved by arranging a hydrogen barrier layer in the piezoelectric device.

[0091] exist Figure 1 and Figure 2 In the embodiment of the present invention, the metal-insulator-metal element MIM has a stepped stacking structure. However, the present disclosure is not limited thereto. Possible modifications and changes may be made to the configuration of the metal-insulator-metal element MIM. Such modifications and changes will be described below with reference to Figure 4 and Figure 5 The descriptions herein provide such modifications and alterations for the purpose of illustration and are not to be construed as limiting the present disclosure.

[0092] Figure 4 Schematic cross-sectional view showing a piezoelectric device according to an alternative embodiment. Figure 4 and Figure 2 , Figure 4 The piezoelectric device 20a is similar to Figure 2 The piezoelectric device 10 is cut along line AA' of the piezoelectric device 10, and thus the same reference numerals are used to refer to the same or similar components, and detailed descriptions thereof are omitted herein. The differences between the piezoelectric device 20a and the piezoelectric device 10 will be described below.

[0093] See Figure 4 In the piezoelectric device 20a, the sidewalls of the first electrode 101, the piezoelectric layer 102, and the second electrode 103 are vertically aligned. Figure 4 As shown in FIG, the sidewalls of the hydrogen barrier layer 104 are vertically aligned with the sidewalls of the first electrode 101, the piezoelectric layer 102, and the second electrode 103. From another perspective, in the piezoelectric device 20a, the hydrogen barrier layer 104 is disposed directly above the second electrode 103 and physically contacts the metal-insulator-metal element MIM at the top surface of the second electrode 103. In detail, as shown in FIG. Figure 4As shown in FIG, the hydrogen barrier layer 104 physically contacts the second electrode 103 at the top surface of the second electrode 103, and does not physically contact the piezoelectric layer 102 and the first electrode 101. In some embodiments, as Figure 4 As shown in FIG. 1 , the hydrogen barrier layer 104 is a single layer. However, the present disclosure is not limited thereto. In some alternative embodiments, the hydrogen barrier layer 104 of the piezoelectric device 20 a is a multi-layer structure.

[0094] Figure 5 Schematic cross-sectional view showing a piezoelectric device according to an alternative embodiment. Figure 5 and Figure 4 , Figure 5 The piezoelectric device 20b and Figure 4 The piezoelectric device 20b is similar to the piezoelectric device 20a, and the main difference between them is that in the piezoelectric device 20b, the sidewalls of the first electrode 101, the piezoelectric layer 102, and the second electrode 103 are inclined sidewalls; while in the piezoelectric device 20a, the sidewalls of the first electrode 101, the piezoelectric layer 102, and the second electrode 103 are vertically aligned. That is, in the piezoelectric device 20b, the metal-insulator-metal element MIM has a tapered profile. In addition, as Figure 5 As shown in FIG, the sidewalls of the hydrogen barrier layer 104 are also inclined sidewalls. In some embodiments, the inclined sidewalls of each of the first electrode 101, the piezoelectric layer 102, the second electrode 103, and the hydrogen barrier layer 104 are aligned with the normal direction of the substrate 100 (as indicated by Figure 5 The angle θ between the substrate 100 and the piezoelectric device 20b (shown by the dashed line in FIG) may be in a range from greater than 0° to about 40°. In some embodiments, the method of forming a metal-insulator-metal (MIM) element having a tapered profile in the piezoelectric device 20b may include adjusting the incident angle of the ion beam relative to the normal direction of the substrate 100 during the ion beam etching step.

[0095] Figure 6A and Figure 6B FIG is a schematic diagram illustrating an exemplary application of a piezoelectric device according to some embodiments. Figure 6A and Figure 6B , two piezoelectric devices 1000 are used to control a variable focus optical system. It should be noted that the piezoelectric device 1000 can be implemented by using the piezoelectric device 10, the piezoelectric device 20a, or the piezoelectric device 20b in the above-mentioned embodiment. In addition, Figure 6A and Figure 6B The number and type of piezoelectric devices 1000 shown in FIG are for illustrative purposes only, and the present disclosure is not limited thereto. In some alternative embodiments, one piezoelectric device 1000 or more than two piezoelectric devices 1000 may be used to control a variable-focus optical system.

[0096] like Figure 6A and Figure 6B As shown in , the variable focus optical system includes a glass carrier 2000, a glass film 2004, and a transparent polymer 2002. The piezoelectric device 1000 is disposed on the glass film 2004. The transparent polymer 2002 having a well-defined optical index can be used to fill the space between the glass carrier 2000 and the glass film 2004. As mentioned above, when a voltage is applied to the piezoelectric device 1000, the piezoelectric layer of each piezoelectric device 1000 can be stretched or compressed to provide a physical displacement in a direction perpendicular to the surface of the glass film 2004. Therefore, each piezoelectric device 1000 applies a force to the glass film 2004 so as to change the position of the glass film 2004 and / or the shape of the glass film 2004. That is, the piezoelectric device 1000 can function as an actuator. Figure 6B As shown in FIG, the piezoelectric device 1000 applies force to the glass film 2004 to cause it to bend accordingly. Figure 6B As shown, the light beam L is focused at the focal point F after passing through the glass carrier 2000, the transparent polymer 2002, and the glass film 2004. It should be noted that since the amount of physical displacement depends roughly on the voltage applied to the piezoelectric device, the position of the focal point F will change by adjusting the magnitude of the applied voltage. In addition, when the piezoelectric device 1000 is in the standby mode, no force is applied to the glass film 2004, and thus the light beam L passes through the glass carrier 2000, the transparent polymer 2002, and the glass film 2004 without deflection, as shown in FIG. Figure 6A shown in.

[0097] In some embodiments, the variable focus optical system may be included in a package of a semiconductor chip having one or more image sensors. For example, in some embodiments, the variable focus optical system may be configured to focus light onto an integrated chip having one or more image sensor devices (e.g., a complementary metal oxide semiconductor (CMOS) image sensor, a charge-coupled device (CCD) image sensor). It should be understood that Figure 6A and Figure 6B The variable focus optical system shown in FIG. 1 is only one example of a possible application of the piezoelectric device 1000. Those skilled in the art will appreciate other possible applications of the piezoelectric device 1000.

[0098] According to some embodiments of the present disclosure, a piezoelectric device is provided, comprising a substrate, a metal-insulator-metal (MIM) element, a hydrogen barrier layer, a passivation layer, a first contact terminal, and a second contact terminal. The MIM element is disposed on the substrate. The hydrogen barrier layer is disposed on the MIM element. The passivation layer covers the hydrogen barrier layer and the MIM element. The first contact terminal is electrically connected to the MIM element. The second contact terminal is electrically connected to the MIM element.

[0099] In some embodiments, the metal-insulator-metal element includes a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on the substrate.

[0100] In some embodiments, the hydrogen barrier layer physically contacts the metal-insulator-metal element at a top surface of the second electrode.

[0101] In some embodiments, the hydrogen barrier layer covers and contacts a top surface of the second electrode and contacts a top surface of the first electrode and a top surface of the piezoelectric layer.

[0102] In some embodiments, the material of the hydrogen barrier layer includes aluminum oxide, titanium dioxide, iron oxide, zirconium dioxide, zinc oxide, copper oxide, or tantalum pentoxide.

[0103] In some embodiments, the thickness of the hydrogen barrier layer located on and in contact with the top surface of the second electrode is greater than the thickness of the hydrogen barrier layer located on and in contact with the top surface of the piezoelectric layer, and the thickness of the hydrogen barrier layer located on and in contact with the top surface of the piezoelectric layer is greater than the thickness of the hydrogen barrier layer located on and in contact with the top surface of the first electrode.

[0104] According to an alternative embodiment of the present disclosure, a piezoelectric device is provided, comprising a substrate, a first electrode, a piezoelectric layer, a second electrode, a hydrogen barrier layer, a passivation layer, a first contact terminal, and a second contact terminal. The first electrode is disposed on the substrate. The piezoelectric layer is disposed on the first electrode. The second electrode is disposed on the piezoelectric layer. The hydrogen barrier layer is disposed on the second electrode and above the substrate. The passivation layer covers the hydrogen barrier layer, the second electrode, the piezoelectric layer, and the first electrode. The first contact terminal is electrically connected to the first electrode. The second contact terminal is electrically connected to the second electrode.

[0105] In some embodiments, the hydrogen barrier layer is disposed directly above and physically contacts the second electrode at a top surface of the second electrode.

[0106] In some embodiments, sidewalls of the first electrode, the piezoelectric layer, and the second electrode are inclined sidewalls.

[0107] In some embodiments, sidewalls of the first electrode, the piezoelectric layer, and the second electrode are vertically aligned.

[0108] In some embodiments, the hydrogen barrier layer includes a first hydrogen barrier layer, a second hydrogen barrier layer, and a third hydrogen barrier layer, wherein the first hydrogen barrier layer contacts the top surface of the second electrode, the second hydrogen barrier layer covers the first hydrogen barrier layer and contacts the top surface of the piezoelectric layer, and the third hydrogen barrier layer covers the second hydrogen barrier layer and contacts the top surface of the first electrode.

[0109] In some embodiments, the first hydrogen barrier layer, the second hydrogen barrier layer, and the third hydrogen barrier layer are made of the same material.

[0110] In some embodiments, in a cross section, the first electrode, the piezoelectric layer, and the second electrode form a stepped stacked structure.

[0111] In some embodiments, the passivation layer and the hydrogen barrier layer have a first contact hole and a second contact hole, the first contact terminal is electrically connected to the first electrode through the first contact hole, and the second contact terminal is electrically connected to the second electrode through the second contact hole.

[0112] In some embodiments, the material of the hydrogen barrier layer includes aluminum oxide, titanium dioxide, iron oxide, zirconium dioxide, zinc oxide, copper oxide, or tantalum pentoxide.

[0113] According to another alternative embodiment of the present disclosure, a method for forming a piezoelectric device is provided, comprising at least the following steps: A first conductive layer, a piezoelectric material layer, and a second conductive layer are sequentially formed on a substrate; a first hydrogen barrier material layer is formed on the second conductive layer; the first hydrogen barrier material layer is patterned to form a first hydrogen barrier layer; and a passivation layer is formed to cover the first hydrogen barrier layer.

[0114] In some embodiments, patterning the first hydrogen barrier material layer to form the first hydrogen barrier layer includes: forming a first photoresist layer on the first hydrogen barrier material layer; and performing a first etching step on the first hydrogen barrier material layer and the second conductive layer by using the first photoresist layer as an etching mask to form the first hydrogen barrier layer and the second electrode.

[0115] In some embodiments, before forming the passivation layer to cover the first hydrogen barrier layer, the method for forming a piezoelectric device further includes: forming a second hydrogen barrier material layer on the first hydrogen barrier layer and the second electrode; forming a second photoresist layer on the second hydrogen barrier material layer; performing a second etching step on the second hydrogen barrier material layer and the piezoelectric material layer by using the second photoresist layer as an etching mask to form a second hydrogen barrier layer and a piezoelectric layer; forming a third hydrogen barrier material layer on the piezoelectric layer and the second hydrogen barrier layer; forming a third photoresist layer on the third hydrogen barrier material layer; and performing a third etching step on the third hydrogen barrier material layer and the first conductive layer by using the third photoresist layer as an etching mask to form a third hydrogen barrier layer and a first electrode.

[0116] In some embodiments, at least one of the first hydrogen barrier material layer, the second hydrogen barrier material layer, and the third hydrogen barrier material layer is formed by atomic layer deposition or physical vapor deposition.

[0117] In some embodiments, at least one of the first etching step, the second etching step, and the third etching step comprises an ion beam etching step.

[0118] The foregoing summarizes the features of several embodiments so that those skilled in the art may better understand the various aspects of the present disclosure. Those skilled in the art will appreciate that they may readily use this disclosure as a basis for designing or modifying other processes and structures for achieving the same purposes and / or achieving the same advantages of the embodiments introduced herein. Those skilled in the art will also recognize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and modifications may be made herein without departing from the spirit and scope of the present disclosure.

Claims

1. A piezoelectric device comprising: substrate; a metal-insulator-metal element disposed on the substrate, wherein the metal-insulator-metal element comprises a first electrode, a piezoelectric layer, and a second electrode stacked sequentially on the substrate; a hydrogen barrier layer disposed on the metal-insulator-metal element, wherein the hydrogen barrier layer covers and contacts a top surface of the second electrode and contacts a top surface of the first electrode and a top surface of the piezoelectric layer, a thickness of the hydrogen barrier layer on and in contact with the top surface of the second electrode is greater than a thickness of the hydrogen barrier layer on and in contact with the top surface of the piezoelectric layer, and a thickness of the hydrogen barrier layer on and in contact with the top surface of the piezoelectric layer is greater than a thickness of the hydrogen barrier layer on and in contact with the top surface of the first electrode; a passivation layer covering the hydrogen barrier layer and the metal-insulator-metal element; a first contact terminal electrically connected to the metal-insulator-metal element; as well as The second contact terminal is electrically connected to the metal-insulator-metal element. 2 . The piezoelectric device of claim 1 , wherein the hydrogen barrier layer physically contacts the metal-insulator-metal element at a top surface of the second electrode. 3 . The piezoelectric device according to claim 1 , wherein a material of the hydrogen barrier layer comprises aluminum oxide, titanium dioxide, iron oxide, zirconium dioxide, zinc oxide, copper oxide, or tantalum pentoxide.

4. A piezoelectric device comprising: substrate; a first electrode disposed on the substrate; a piezoelectric layer disposed on the first electrode; a second electrode disposed on the piezoelectric layer; a hydrogen barrier layer disposed on the second electrode and over the substrate, wherein the hydrogen barrier layer comprises a first hydrogen barrier layer, a second hydrogen barrier layer, and a third hydrogen barrier layer, the first hydrogen barrier layer contacts a top surface of the second electrode, the second hydrogen barrier layer covers the first hydrogen barrier layer and contacts a top surface of the piezoelectric layer, and the third hydrogen barrier layer covers the second hydrogen barrier layer and contacts a top surface of the first electrode; a passivation layer covering the hydrogen barrier layer, the second electrode, the piezoelectric layer and the first electrode; a first contact terminal electrically connected to the first electrode; as well as The second contact terminal is electrically connected to the second electrode. 5 . The piezoelectric device of claim 4 , wherein the hydrogen barrier layer is disposed directly above the second electrode and physically contacts the second electrode at a top surface of the second electrode. 6 . The piezoelectric device according to claim 5 , wherein side walls of the first electrode, the piezoelectric layer, and the second electrode are inclined side walls. 7 . The piezoelectric device according to claim 5 , wherein sidewalls of the first electrode, the piezoelectric layer, and the second electrode are vertically aligned. 8 . The piezoelectric device according to claim 4 , wherein the first hydrogen barrier layer, the second hydrogen barrier layer, and the third hydrogen barrier layer are made of the same material. 9 . The piezoelectric device according to claim 4 , wherein the first electrode, the piezoelectric layer, and the second electrode form a stepped stack structure.

10. The piezoelectric device according to claim 4, wherein the passivation layer and the hydrogen barrier layer have a first contact hole and a second contact hole, the first contact terminal is electrically connected to the first electrode through the first contact hole, and the second contact terminal is electrically connected to the second electrode through the second contact hole. 11 . The piezoelectric device according to claim 4 , wherein a material of the hydrogen barrier layer comprises aluminum oxide, titanium dioxide, iron oxide, zirconium dioxide, zinc oxide, copper oxide, or tantalum pentoxide.

12. A method of forming a piezoelectric device, comprising: forming a first conductive layer, a piezoelectric material layer, and a second conductive layer on the substrate in sequence; forming a first hydrogen barrier material layer on the second conductive layer; patterning the first hydrogen barrier material layer to form a first hydrogen barrier layer; as well as forming a passivation layer to cover the first hydrogen barrier layer, Before forming the passivation layer to cover the first hydrogen barrier layer, the method for forming a piezoelectric device further comprises: forming a second hydrogen barrier material layer on the first hydrogen barrier layer; forming a second photoresist layer on the second hydrogen barrier material layer; performing a second etching step on the second hydrogen barrier material layer and the piezoelectric material layer by using the second photoresist layer as an etching mask to form a second hydrogen barrier layer and a piezoelectric layer; forming a third hydrogen barrier material layer on the piezoelectric layer and the second hydrogen barrier layer; forming a third photoresist layer on the third hydrogen barrier material layer; and A third etching step is performed on the third hydrogen barrier material layer and the first conductive layer by using the third photoresist layer as an etching mask to form a third hydrogen barrier layer and a first electrode.

13. The method of forming a piezoelectric device according to claim 12, wherein patterning the first hydrogen barrier material layer to form the first hydrogen barrier layer comprises: forming a first photoresist layer on the first hydrogen barrier material layer; as well as The first hydrogen barrier layer and the second electrode are formed by performing a first etching step on the first hydrogen barrier material layer and the second conductive layer using the first photoresist layer as an etching mask. 14 . The method of forming a piezoelectric device according to claim 12 , wherein at least one of the first hydrogen barrier material layer, the second hydrogen barrier material layer, and the third hydrogen barrier material layer is formed by atomic layer deposition or physical vapor deposition. 15 . The method of forming a piezoelectric device according to claim 13 , wherein at least one of the first etching step, the second etching step, and the third etching step comprises an ion beam etching step.

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