Resonator, resonator assembly, filter, and electronic device

Abstract

The present application provides a kind of resonator, resonator assembly, filter and electronic equipment.The resonator includes substrate;Acoustic mirror;Seed layer;Bottom electrode, formed on seed layer;Piezoelectric layer;And top electrode;The overlapping part of acoustic mirror, bottom electrode, piezoelectric layer and top electrode collectively forms the effective area of resonator;Wherein, the area of seed layer covering effective area in the transverse direction of resonator is less than the area of effective area, to adjust the effective electromechanical coupling coefficient of resonator by changing the area of seed layer covering effective area.The present application can adjust the effective electromechanical coupling coefficient and other parameters of resonator by changing the area of seed layer covering effective area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, and in particular, to a resonator, a resonator assembly, a filter and an electronic device. BACKGROUND

[0002] With the development of modern wireless communication technology towards high frequency and high speed, filter devices such as resonators, for example, Film Bulk Acoustic Resonator (FBAR) based filters, duplexers and the like, are increasingly favored by the market.

[0003] At present, the filter generally includes a plurality of Film Bulk Acoustic Resonators. Each resonator includes a substrate, and acoustic mirrors, seed layers, lower electrodes, piezoelectric layers, upper electrodes and the like film layers which are sequentially stacked on the substrate. Among them, the thickness ratio of the upper electrode, the lower electrode and the piezoelectric layer in the resonator will determine the parameters of the resonator, and in the filter, each resonator may need to have different performance parameters.

[0004] However, in the existing Film Bulk Acoustic Resonator, the effective electromechanical coupling coefficient Kt is difficult to be freely set and adjusted without changing the thickness of each film layer in the resonator. SUMMARY

[0005] In view of the above problems, the present application provides a resonator, a resonator assembly, a filter and an electronic device, which can adjust the effective electromechanical coupling coefficient of the resonator.

[0006] In order to achieve the above purpose, the first aspect of the present application provides a resonator, comprising a substrate; an acoustic mirror; a seed layer; a bottom electrode formed on the seed layer; a piezoelectric layer; and a top electrode; the overlapping parts of the acoustic mirror, the bottom electrode, the piezoelectric layer and the top electrode together form an effective area of the resonator; wherein the area of the seed layer covering the effective area in the lateral direction of the resonator is less than the area of the effective area, so as to adjust the effective electromechanical coupling coefficient of the resonator by changing the area of the seed layer covering the effective area.

[0007] In an optional implementation, the seed layer covers at least part of the acoustic mirror; and the seed layer covers part of the effective area in the lateral direction of the resonator.

[0008] In an optional implementation, the ratio of the part of the seed layer covering the effective area to the area of the effective area is between 0.1 and 0.9.

[0009] In an optional implementation, the part of the seed layer covering the effective area is continuous.

[0010] In an optional implementation, the seed layer is a hollow ring.

[0011] In an optional embodiment, the seed layer comprises at least two covering portions, the different covering portions have a spacing in the lateral direction of the resonator, and the covering portions and the effective area have an overlapping portion in the lateral direction of the resonator.

[0012] In an optional embodiment, the covering portions and the effective area partially overlap in the lateral direction of the resonator; or, the covering portions are completely located within the effective area in the lateral direction of the resonator.

[0013] In an optional embodiment, the thicknesses of the different covering portions in the lateral direction of the resonator are uniform.

[0014] In an optional embodiment, the at least two covering portions comprise a first covering portion and a second covering portion, the second covering portion is a hollow ring, the first covering portion is located in an area surrounded by the second covering portion and has a spacing from the inner side of the second covering portion.

[0015] In an optional embodiment, the center of the effective area in the lateral direction of the resonator passes through the first covering portion.

[0016] In an optional embodiment, the acoustic mirror comprises an air cavity.

[0017] In an optional embodiment, the air cavity is formed by inwardly recessing the substrate surface.

[0018] In an optional embodiment, the air cavity is located on the side of the substrate surface facing the bottom electrode.

[0019] The resonator further comprises a sandwich electrode, the sandwich electrode is arranged on the substrate, and the sandwich electrode and the seed layer collectively enclose the outside of the air cavity, and the sandwich electrode and the bottom electrode are connected to each other and conductive.

[0020] In an optional embodiment, an etching stop layer is further included, the etching stop layer is arranged on the sandwich electrode and located in the air cavity.

[0021] In an optional embodiment, the material of the seed layer comprises at least one of aluminum nitride, zinc oxide and lead zirconate titanate.

[0022] The second aspect of the present application provides a resonator assembly comprising at least one of the above-mentioned resonators, the seed layers in different resonators have different proportions of the area of the covering effective area to the area of the effective area in the lateral direction of the resonator.

[0023] The third aspect of the present application provides a filter comprising the above-mentioned resonator or resonator assembly.

[0024] The fourth aspect of the present application provides an electronic device comprising the above-mentioned filter.

[0025] The resonator, resonator assembly, filter and electronic device of the present application. The resonator comprises a substrate; an acoustic mirror; a seed layer; a bottom electrode formed on the seed layer; a piezoelectric layer; and a top electrode; the overlapping parts of the acoustic mirror, bottom electrode, piezoelectric layer and top electrode jointly form an effective area of the resonator; wherein the area of the seed layer covering the effective area in the lateral direction of the resonator is less than the area of the effective area, so as to adjust the effective electromechanical coupling coefficient Kt of the resonator by changing the area of the seed layer covering the effective area. In the above scheme, the area of the seed layer covering the effective area in the lateral direction of the resonator is less than the area of the effective area, so that in the effective area of the resonator, a part of the area is formed with the seed layer, in which part the bottom electrode can be deposited on the seed layer, and the crystal orientation is preferable; another part of the area is formed with the bottom electrode directly deposited on the substrate, and the crystal orientation is less preferable, which makes the proportion of the preferable crystal orientation in the whole effective area adjustable in the range less than 1, so as to make the resonator have an adjustable effective electromechanical coupling coefficient Kt, so as to facilitate the adjustment of the performance of the filter. In other words, as long as the ratio of the part of the seed layer covering the effective area to the area of the effective area is adjusted, different Kt can be obtained, and the selection of the Kt degree of freedom is realized. In this way, the selection of the Kt degree of freedom in the resonator is realized, which not only has a simple process and is easy to realize, but also does not need to change the effective area of the resonator. The selectable range is also relatively wide, and the flexibility is relatively high.

[0026] The configuration of the present application and other inventive objects and beneficial effects thereof will be more apparent and understandable through the description of the preferred embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a top view of the resonator provided by the embodiment of the present application;

[0028] Figure 2 is Figure 1 is a sectional view obtained by cutting along A-O-A' in the figure;

[0029] Figure 3 is a comparison schematic diagram of the effective electromechanical coupling coefficients of the resonator without seed layer in the embodiment of the present application and the resonator with seed layer in the prior art;

[0030] Figure 4 is a curve diagram showing the relationship between the ratio of the seed layer to the area of the effective area and the effective electromechanical coupling coefficient in the resonator provided by the embodiment of the present application;

[0031] Figure 5 is a schematic diagram of another structure of the resonator provided by the embodiment of the present application;

[0032] Figure 6 is a schematic diagram of another structure of the resonator provided by the embodiment of the present application;

[0033] Figure 7 A schematic diagram of still another structure of a resonator provided for an embodiment of the present application;

[0034] Figure 8 A schematic diagram of still another structure of a resonator provided for an embodiment of the present application;

[0035] Figure 9 A schematic diagram of still another structure of a resonator provided for an embodiment of the present application.

[0036] Explanation of reference signs:

[0037] 1 - substrate; 2, 2' - air cavity; 3 - bottom electrode; 4 - piezoelectric layer; 5 - top electrode; 6 - passivation layer; 7 - interlayer electrode; 10 - etching stop layer; 8, 9 - seed layer; 80, 90 - covering part; 81, 91 - first covering part; 82, 92 - second covering part; 100, 100' - resonator. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0039] A resonator is a commonly used electronic device for composing filter devices such as filters. The current resonator can include types such as a thin film bulk acoustic resonator. Taking the commonly used thin film bulk acoustic resonator as an example, it is specifically formed by a multi-layer laminated structure. The multi-layer laminated structure includes two oppositely arranged plate electrodes and a piezoelectric material arranged between the two plate electrodes. When a voltage is applied to the plate electrode, the piezoelectric material generates an acoustic wave, and further forms a resonance.

[0040] However, the effective electromechanical coupling coefficient kt and other parameters of the thin film bulk acoustic resonator are determined by the thickness ratio of the electrode and the piezoelectric layer, so it is difficult to freely adjust and set the kt between different resonators inside the same filter design.

[0041] In the present application, the area of the seed layer covering the effective area in the lateral direction of the resonator is less than the area of the effective area. As long as the size of the area of the seed layer covering the effective area is changed, different effective electromechanical coupling coefficients Kt can be obtained, the freedom of the resonator Kt is selected, and the performance of the filter is adjustable.

[0042] The resonator 100, the filter and the electronic device of the embodiments of the present application will be described below with reference to the drawings.

[0043] First, the materials of each layer in the resonator 100 appearing in this application are described.

[0044] The material of the substrate 1 can be: single crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, or a single crystal piezoelectric substrate 1 such as lithium niobate, lithium tantalate, or potassium niobate.

[0045] The acoustic mirror can be an air cavity, a Bragg reflection layer or other equivalent forms.

[0046] The material of the seed layer 8 can be at least one of aluminum nitride (AlN), zinc oxide (ZnO), single crystal lead zirconate titanate (PZT), etc., or a rare earth element doped material containing a certain atomic ratio of the above materials.

[0047] The piezoelectric layer 4 may be aluminum nitride, zinc oxide, single crystal lead zirconate titanate, etc. The piezoelectric material may also be a rare earth element doped material containing a certain atomic ratio of the above materials.

[0048] The material of the top electrode 5 can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite of the above metals or an alloy thereof.

[0049] The material of the bottom electrode 3 can be the same as that of the top electrode 5, and the material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or a composite of the above metals or an alloy thereof. The bottom electrode 3 and the top electrode 5 are generally made of the same material, but can also be different.

[0050] The material of the interlayer electrode 7 can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite of the above metals or an alloy thereof.

[0051] The material of the passivation layer 6 can be silicon dioxide, aluminum nitride, silicon nitride or other types of dielectric materials.

[0052] The etch stop layer 10 may be made of materials such as aluminum nitride, zinc oxide, single crystal lead zirconate titanate (PZT), or a rare earth element doped material containing the above materials in a certain atomic ratio.

[0053] The following is a detailed introduction to the specific structure and various possible implementation forms of the resonator in conjunction with specific embodiments. It should be noted that in this application, the vertical direction of the resonator refers to the stacking direction of the layers of the resonator, that is, the thickness direction of the resonator, and the horizontal direction of the resonator refers to the direction perpendicular to the vertical direction, for example Figure 2 Horizontal direction in .

[0054] Figure 1 This is a schematic top view of a resonator provided in an embodiment of the present application. Figure 2 yes Figure 1The cross-sectional view is obtained by cutting along AO-A'.

[0055] Reference Figure 1 、 Figure 2 The present invention provides a resonator 100 comprising a substrate 1, an acoustic mirror, a seed layer 8, a bottom electrode 3, a piezoelectric layer 4, and a top electrode 5. Optionally, the seed layer 8 may at least partially cover the acoustic mirror; the bottom electrode 3 is formed on the seed layer 8. The overlapping portion of the acoustic mirror, bottom electrode 3, piezoelectric layer 4, and top electrode 5 together form the active region of the resonator 100.

[0056] Among them, those skilled in the art can understand that, in some other embodiments, the resonator 100 also includes structures such as a passivation layer 6 formed on the top electrode 5, and the passivation layer 6 covers the top electrode 5, thereby protecting the top electrode 5 and other structures.

[0057] Optionally, the substrate 1, acoustic mirror, seed layer 8, bottom electrode 3, piezoelectric layer 4, top electrode 5 and passivation layer 6 are sequentially stacked. In addition, the area of ​​the seed layer 8 covering the active region in the lateral direction of the resonator is smaller than the area of ​​the active region.

[0058] In other words, in one possible scenario, the seed layer 8 will cover part of the effective area in the lateral direction of the resonator 100. In this case, it can be understood that the ratio of the area covered by the seed layer 8 in the effective area to the area of ​​the effective area is less than 1 and greater than 0; and in another possible scenario, the seed layer 8 does not cover the effective area in the lateral direction of the resonator 100. In this case, the area covered by the seed layer 8 in the effective area is also smaller than the area of ​​the effective area, and in this case, the ratio of the area covered by the seed layer 8 in the effective area to the area of ​​the effective area is 0. It should be noted that the situation where the seed layer 8 does not cover the effective area in the lateral direction of the resonator 100 can be considered to be equivalent to the fact that the seed layer 8 does not exist in the resonator 100, that is, the bottom electrode 3 is directly arranged on the acoustic mirror.

[0059] Since the area of ​​the effective area covered by the seed layer 8 in the lateral direction of the resonator 100 is always smaller than the area of ​​the effective area itself, in the embodiment of the present application, the effective electromechanical coupling coefficient Kt of the resonator can be adjusted by changing the area of ​​the seed layer 8 covering the effective area.

[0060] In the above scheme, by forming a seed layer 8 on the substrate 1 before forming the bottom electrode 3 and other electrode film layers, the seed layer 8 can induce the crystal growth of the bottom electrode 3 and other electrode film layers in the vertical direction, so that the bottom electrode 3 and other electrode film layers form a good crystal orientation, thereby improving the effective electromechanical coupling coefficient Kt of the resonator 100 to optimize the performance of the resonator 100.

[0061] The seed layer 8 covers at least part of the acoustic mirror, which means that the seed layer 8 can cover the whole acoustic mirror or only part of the acoustic mirror.

[0062] In this case, the seed layer 8 can be formed by sputtering through physical vapor deposition (PVD). For example, the seed layer 8 can be formed by sputtering ALN through physical vapor deposition on the substrate 1. When the bottom electrode 3 is deposited on the seed layer 8, the seed layer 8 can induce the growth of the crystal direction in the vertical direction of the bottom electrode 3, so that the crystal direction of the bottom electrode 3 is better. Furthermore, the seed layer 8 can induce the growth of the crystal direction in the piezoelectric layer 4 deposited on the bottom electrode 3 to be better, so as to improve the effective electromechanical coupling coefficient kt of the resonator 100.

[0063] Figure 3 is a comparison diagram of the effective electromechanical coupling coefficients of the resonator without a seed layer in the embodiment of the present application and the resonator with a seed layer.

[0064] Referring to Figure 3 It can be seen that the effective electromechanical coupling coefficient Kt of the resonator 100 is 7.9% when the resonator 100 does not have a seed layer, and the effective electromechanical coupling coefficient Kt of the resonator 100 is 11.3% when the resonator 100 has the seed layer 8. Therefore, the effective electromechanical coupling coefficient of the resonator 100 is improved when the seed layer 8 is formed on the substrate 1.

[0065] In the embodiment of the present application, the seed layer 8 covers part of the effective area in the lateral direction of the resonator 100, which means that the projection of the effective area and the projection of the seed layer 8 on the substrate 1 have an overlapping area. Furthermore, the seed layer 8 does not cover the whole effective area in the lateral direction of the resonator 100, but only covers part of the effective area.

[0066] In the example of Figure 2 The part of the seed layer 8 covering the effective area is continuous.

[0067] It can be understood that the size of the effective area covered by the seed layer 8 in the lateral direction of the resonator 100 can determine the size of the effective electromechanical coupling coefficient of the resonator 100. This is because the seed layer 8 can directly induce the growth of the crystal direction in the bottom electrode 3, so the size of the seed layer 8 covering the effective area can directly determine how much area in the effective area will be induced by the crystal direction.

[0068] In other words, in the resonator 100, the part with the seed layer 8 induces the electrode layer crystal orientation growth, and the electrode layer such as the bottom electrode 3 is well oriented in this part; while in the part without the seed layer 8, the electrode layer such as the bottom electrode 3 is directly deposited on the surface of the substrate 1, and the quality of the electrode layer is not good, and the crystal orientation of the piezoelectric layer 4 is not good either. As described above, in the same resonator 100, in one part of the effective area, the seed layer 8 is formed, and the bottom electrode 3 is deposited on the seed layer 8; in another part of the effective area, the bottom electrode 3 is directly deposited on the substrate 1, and the effective electromechanical coupling coefficient Kt corresponding to different areas of the resonator 100 is different, and different Kt can be obtained by adjusting the area ratio of the part of the seed layer 8 covering the effective area to the effective area, and the selection of the Kt degree of freedom is realized.

[0069] In the embodiment of the present application, if the selection of the Kt degree of freedom in the resonator 100 is realized by adjusting the area ratio of the part of the seed layer 8 covering the effective area to the effective area, the process is simple and easy to implement, and the effective area of the resonator 100 does not need to be changed. That is, the range of the selectable effective electromechanical coupling coefficient Kt can be adjusted according to the area ratio of the seed layer 8 to the effective area, and the range is wide and the flexibility is high.

[0070] The area ratio of the part of the seed layer covering the effective area to the effective area refers to the projection of the seed layer 8 and the effective area on the substrate 1, and the area ratio of the projection of the part of the seed layer covering the effective area to the projection of the effective area.

[0071] Optionally, the area ratio of the part of the seed layer covering the effective area to the effective area is between 0.1 and 0.9.

[0072] Figure 4 The resonator provided in the embodiment of the present application shows the relationship between the area ratio of the seed layer to the effective area and the effective electromechanical coupling coefficient. Referring to Figure 4 , for example, when the thicknesses of the top electrode 5, the bottom electrode 3 and the piezoelectric layer 4 are preset values, the effective electromechanical coupling coefficient Kt and the area ratio P of the seed layer to the effective area of the resonator follow the following formula:

[0073] The effective electromechanical coupling coefficient Kt=0.034*the area ratio P of the part of the seed layer covering the effective area to the effective area+0.079.

[0074] Experiments show that when the resonator 100 has no seed layer, i.e. the area ratio of the seed layer to the effective area of the resonator 100 is 0, the Kt of the resonator 100 is the lowest; when the seed layer 8 accounts for the entire effective area of the resonator 100, i.e. the area ratio of the seed layer 8 to the effective area of the resonator 100 is 1, the performance of the resonator 100 is the best and the Kt is the highest. When the area ratio of the seed layer 8 to the effective area of the resonator 100 is between 0 and 1, the Kt of the resonator 100 follows the above formula, so that different Kt can be realized in the same resonator 100, and the required Kt can be freely selected by the area ratio of the seed layer 8 to the effective area of the resonator 100.

[0075] Figure 5 FIG. 4 is a schematic view of another structure of a resonator provided in an embodiment of the present application, Figure 6 FIG. 5 is a schematic view of still another structure of a resonator provided in an embodiment of the present application.

[0076] In the embodiment of the present application, the seed layer 8 can have a plurality of different shapes, for example, the seed layer 8 can be a symmetrical structure or an asymmetrical structure, and the covering portion can be a hollow structure or a non-hollow structure.

[0077] In addition, the seed layer 8 can be a single structure or a split structure composed of at least two separated parts. Figure 5 Another resonator cross-sectional structure is listed when the seed layer 8 is a single structure. Specifically, in some embodiments, the seed layer is in a hollow ring shape, at this time, the cross section of the seed layer 8 is in a discontinuous shape with a break in the middle, as shown in FIG. 6. Figure 5 As can be understood by those skilled in the art, in addition to the seed layer 8 structures shown in FIGS. 6 and 7, the seed layer 8 can also have other shapes. Figure 1 and Figure 5 As can be understood by those skilled in the art, in addition to the seed layer 8 structures shown in FIGS. 6 and 7, the seed layer 8 can also have other shapes.

[0078] Referring to FIG. 8, Figure 6 When the seed layer 8 has a split structure, the seed layer 8 can also include at least two covering portions 80, and the different covering portions 80 have a spacing in the lateral direction of the resonator 100, and the covering portion 80 and the effective area have an overlapping portion in the lateral direction of the resonator 100.

[0079] This includes two cases. One is that the covering portion 80 and the effective area partially overlap in the lateral direction of the resonator 100, which means that at least part of the covering portion 80 is located outside the effective area.

[0080] The other is that the covering portion 80 is completely located within the effective area in the lateral direction of the resonator 100, which means that the projection of the covering portion 80 on the substrate 1 is completely within the projection range of the effective area on the substrate 1.

[0081] It should be noted that, to facilitate deposition and obtain a more stable effective electromechanical coupling coefficient, in some embodiments, the thicknesses of different covering portions 80 in the lateral direction of the resonator 100 are uniform. In other embodiments, the thicknesses of different covering portions 80 in the lateral direction of the resonator 100 may also be inconsistent.

[0082] Or, refer to Figure 6 The at least two covering parts 80 include a first covering part 81 and a second covering part 82. The second covering part 82 is hollow and annular. The first covering part 81 is located in the area surrounded by the second covering part 82 and is spaced apart from the inner side of the second covering part 82. In this way, the first covering part 81 is actually located in the area surrounded by the second covering part 82.

[0083] Optionally, the center of the effective area in the transverse direction of the resonator 100 passes through the first covering portion 81. In this way, with the same area ratio of the seed layer 8 to the effective area of ​​the resonator 100, the effective electromechanical coupling coefficient Kt of the resonator 100 can be made higher.

[0084] In the embodiment of the present application, the acoustic mirror may include an air cavity 2. Here, the formation position of the air cavity 2 may be selected according to actual needs and may be located in the substrate 1. As an optional embodiment, refer to Figure 2 、 Figure 5 、 Figure 6 The resonator 100 shown is a case where the air cavity 2 is located in the substrate 1. The air cavity 2 is formed by recessing the surface of the substrate 1. In actual manufacturing processes, the air cavity 2 can be formed by using a sacrificial layer or the like.

[0085] The formation position of the air cavity 2 also includes the case where it is formed above the substrate 1. Figure 7 、 Figure 8 、 Figure 9 Resonator 100' is a resonator in which air cavity 2' is formed above substrate 1. It should be noted that, compared to resonator 100, resonator 100' improves the formation position of the air cavity and adds some membrane layers. The remaining parts, such as the seed layer covering part of the active area in the lateral direction of the resonator, and the ratio of the portion of the seed layer covering the active area to the area of ​​the active area is between 0.1 and 0.9, are the same as those of resonator 100 and will not be repeated here.

[0086] In the resonator 100', the selection of the kt degree of freedom in the resonator is also realized by the ratio of the portion of the seed layer 9 covering the effective area to the area of the effective area. Moreover, since the Chemical Mechanical Polishing (CMP) process is removed, the process can be optimized, the cost can be saved, and the impedance value of the resonator can be reduced, which has a more obvious effect of reducing the resistance for the resonator of high frequency, and effectively improves the performance of the resonator.

[0087] The structure of the resonator 100' will be described in detail below.

[0088] Specifically, in the resonator 100', the air cavity 2' is located on the side of the substrate 1 surface facing the bottom electrode 3. Moreover, the resonator 100' further comprises a sandwich electrode 7, which is arranged on the substrate 1, and the sandwich electrode 7 and the seed layer 9 jointly enclose the outside of the air cavity 2', and the sandwich electrode 7 and the bottom electrode 3 are connected and conductive to each other.

[0089] Optionally, the resonator 100' further comprises an etching stop layer 10, which can be arranged on the sandwich electrode 7 and located in the air cavity 2'. The etching stop layer 10 is used to assist the formation of the air cavity 2'.

[0090] Specifically, referring to Figure 7 The seed layer 9 partially covers the air cavity 2', at this time, the seed layer 9 partially covers the effective area, and the portion of the seed layer 9 covering the effective area is continuous.

[0091] Corresponding to various structures of the seed layer 8 in the resonator 100, the resonator 100' also has the case that the seed layer 9 is a single body or a split body. Referring to Figure 8 As an optional way, the seed layer 9 is a hollow ring.

[0092] In another optional way, similar to the resonator 100, the seed layer 9 can comprise at least two covering portions 90, the different covering portions 90 have a spacing in the lateral direction of the resonator 100', and the covering portion 90 and the effective area have an overlapping portion in the lateral direction of the resonator 100'.

[0093] This includes two cases. One is that the covering portion 90 and the effective area partially overlap in the lateral direction of the resonator 100', which means that at least part of the covering portion 90 is located outside the effective area.

[0094] The other is that the covering portion 90 is completely located in the effective area in the lateral direction of the resonator 100', which means that the projection of the covering portion 90 on the substrate 1 is completely located within the projection range of the effective area on the substrate 1.

[0095] It should be noted that, in order to facilitate deposition and obtain a more stable effective electromechanical coupling coefficient, the thickness of the different cover portions 90 in the lateral direction of the resonator 100' should be uniform.

[0096] In the present application, the number of cover portions 90 can be two or more, for example. Figure 9 The case where the number of cover portions 90 in the resonator 100' is two is shown.

[0097] Referring to Figure 9 As another alternative, the cover portion 90 can include a first cover portion 91 and a second cover portion 92, the second cover portion 92 being a hollow ring, and the first cover portion 91 being located in the area surrounded by the second cover portion 92 and having a spacing from the inner side of the second cover portion 92. In this way, the first cover portion 91 is actually located in the area surrounded by the second cover portion 92.

[0098] Optionally, the center of the effective area in the lateral direction of the resonator 100' passes through the first cover portion 91. In this way, the effective electromechanical coupling coefficient Kt of the resonator 100' can be made higher under the condition that the seed layer 8 occupies the same area ratio of the effective area of the resonator 100'.

[0099] In the present application, the resonator includes a substrate, an acoustic mirror, a seed layer covering at least part of the acoustic mirror, a bottom electrode formed on the seed layer, a piezoelectric layer, a top electrode, and a passivation layer; the substrate, the acoustic mirror, the seed layer, the bottom electrode, the piezoelectric layer, the top electrode, and the passivation layer are sequentially stacked, and the overlapping parts of the acoustic mirror, the bottom electrode, the piezoelectric layer, and the top electrode together form the effective area of the resonator; wherein the seed layer covers part of the effective area in the lateral direction of the resonator. In the above scheme, by adjusting the area ratio of the part of the seed layer covering the effective area to the effective area, different effective electromechanical coupling coefficients Kt can be obtained, realizing the selection of Kt degrees of freedom. In this way, the selection of Kt degrees of freedom in the resonator is realized, which is not only simple in process and easy to implement, but also does not need to change the effective area of the resonator. The alternative range is also relatively wide, and the flexibility is relatively high.

[0100] It is understandable that the present application also provides a resonator assembly, including at least one resonator described in the above embodiment, and the ratio of the area of ​​the effective area covered by the seed layer in the lateral direction of the resonator to the area of ​​the effective area is different in different resonators. Exemplarily, the resonator assembly may include two resonators, and the seed layer in one resonator completely covers the effective area, while the seed layer in the other resonator only covers part of the effective area in the lateral direction of the resonator; or, the resonator may also include two resonators, the seed layers of both resonators cover part of the effective area, and the area of ​​the effective area covered by the seed layer in the two resonators accounts for a different ratio of the area of ​​the corresponding effective area. By analogy, the resonator assembly may also include more than two resonators, and the situation when there are more than two resonators will not be repeated here. It is understandable that the number of resonators in the resonator assembly and the area ratio of the effective area occupied by the seed layer in each resonator can be set as needed.

[0101] As those skilled in the art will appreciate, the resonators 100 and 100' according to the present invention can be used to form filters or electronic devices. In addition to the resonators 100 and 100' described in the aforementioned embodiments, the filters may also be coupled or configured with other basic components. Specifically, the specific structure, function, and main operating principles of the resonators 100 and 100' in the filters and electronic devices have been described in detail in the aforementioned embodiments and will not be further elaborated here.

[0102] The electronic devices here include the above-mentioned filters. The electronic devices include but are not limited to intermediate products such as RF front-ends, filter amplifier modules, and terminal products such as mobile phones, WIFI, and drones.

[0103] In the present invention, the terms "up" and "down" are relative to the bottom surface of the substrate of the resonator. For a component, the side close to the bottom surface is the bottom side, and the side away from the bottom surface is the top side.

[0104] In the present invention, the terms "inside" and "outside" are relative to the center of the effective area of ​​the resonator in the transverse direction or radial direction. The side or end of a component closer to the center is the inside or inner end, while the side or end of the component farther from the center is the outside or outer end. With respect to a reference position, being located inside the position means being between the position and the center in the transverse direction or radial direction, while being located outside the position means being farther from the center in the transverse direction or radial direction than the position.

[0105] In the description of the application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixedly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements, or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0106] The terms "first", "second", "third", "fourth" and the like in the description of the present application and claims, and the above-mentioned drawings (if any) are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein.

[0107] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device containing a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0108] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A resonator, characterized in that include: substrate; Acoustic mirror; seed layer; a bottom electrode formed on the seed layer; Piezoelectric layer; as well as Top electrode; The acoustic mirror, the bottom electrode, the piezoelectric layer, and the overlapping portion of the top electrode together form an active area of ​​the resonator; The area of ​​the effective region covered by the seed layer in the lateral direction of the resonator is smaller than the area of ​​the effective region, so that the effective electromechanical coupling coefficient of the resonator can be adjusted by changing the area of ​​the seed layer covering the effective region.

2. The resonator according to claim 1, characterized in that The seed layer covers at least a portion of the acoustic mirror; and the seed layer covers a portion of the active area in a lateral direction of the resonator.

3. The resonator according to claim 2, characterized in that The ratio of the portion of the seed layer covering the active area to the area of ​​the active area is between 0.1 and 0.

9.

4. The resonator according to any one of claims 1 to 3, characterized in that The portion of the seed layer covering the effective area is continuous.

5. The resonator according to any one of claims 1 to 3, characterized in that: The seed layer is in a hollow ring shape.

6. The resonator according to any one of claims 1 to 3, characterized in that: The seed layer includes at least two covering portions, different covering portions are spaced apart in a lateral direction of the resonator, and the covering portions and the active region have overlapping portions in the lateral direction of the resonator.

7. The resonator according to claim 6, characterized in that The covering portion and the active region partially overlap in the transverse direction of the resonator; or, the covering portion is completely located within the active region in the transverse direction of the resonator.

8. The resonator according to claim 6, characterized in that The thicknesses of the different covering parts in the transverse direction of the resonator are all consistent.

9. The resonator according to claim 6, characterized in that The at least two covering parts include a first covering part and a second covering part. The second covering part is hollow and annular. The first covering part is located in the area surrounded by the second covering part and has a distance from the inner side of the second covering part.

10. The resonator according to claim 9, characterized in that The center of the effective region in the lateral direction of the resonator passes through the first covering portion.

11. The resonator according to any one of claims 1 to 3, characterized in that: The acoustic mirror includes an air cavity.

12. The resonator according to claim 11, characterized in that The air cavity is formed by inward depression of the substrate surface.

13. The resonator according to claim 11, characterized in that The air cavity is located on a side of the substrate surface facing the bottom electrode; The resonator further includes an interlayer electrode, which is disposed on the substrate. The interlayer electrode and the seed layer jointly surround the outside of the air cavity. The interlayer electrode and the bottom electrode are interconnected and conductive.

14. The resonator according to claim 13, characterized in that The invention also includes an etching stopper layer, which is arranged on the interlayer electrode and located in the air cavity.

15. The resonator according to claim 14, characterized in that The material of the seed layer includes at least one of aluminum nitride, zinc oxide, and lead zirconate titanate.

16. A resonator assembly, characterized in that The resonator assembly comprises at least one resonator according to any one of claims 1 to 15, wherein the ratio of the area of ​​the seed layer covering the active region in the lateral direction of the resonator to the area of ​​the active region is different in different resonators.

17. A filter, characterized in that: The invention comprises the resonator according to any one of claims 1 to 15 or the resonator assembly according to claim 16.

18. An electronic device, characterized in that: Comprising the filter according to claim 17.

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