Bulk acoustic wave resonator, filter and electronic device with additional structure separated from top electrode

Abstract

The present invention relates to a bulk acoustic wave resonator, comprising: a substrate; an acoustic mirror; a bottom electrode, arranged above the substrate; a top electrode, having an electrode connection portion; and a piezoelectric layer, arranged above the bottom electrode and between the bottom electrode and the top electrode, wherein: the resonator further comprises an additional structure, the additional structure is arranged at the edge of the top electrode and there is a gap between the top electrode and the additional structure; the resonator further comprises a non-conductive material layer, the non-conductive material layer fills the gap and covers at least a portion of the additional structure and / or at least a portion of the top electrode. The present invention also relates to an electronic device having the above-mentioned semiconductor device.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of semiconductors, and in particular to a bulk acoustic wave resonator in which an additional structure is separated from a top electrode, a filter having the resonator, and an electronic device having the resonator or the filter. Background Art

[0002] Film Bulk Acoustic Resonator (FBAR, also known as BAW) plays an important role in the communication field as a MEMS chip. FBAR filter has excellent characteristics such as small size (μm level), high resonance frequency (GHz), high quality factor (1000), large power capacity, and good roll-off effect. It is gradually replacing traditional surface acoustic wave (SAW) filters and ceramic filters, and plays a huge role in the field of wireless communication radio frequency. Its high sensitivity advantage can also be applied to biological, physical, medical and other sensing fields.

[0003] The main structure of the film bulk acoustic wave resonator is a "sandwich" structure consisting of electrode-piezoelectric film-electrode, that is, a layer of piezoelectric film material is sandwiched between two layers of metal electrode layers. By inputting a sinusoidal signal between the two electrodes, the FBAR uses the inverse piezoelectric effect to convert the input electrical signal into mechanical resonance, and then uses the piezoelectric effect to convert the mechanical resonance into an electrical signal output. The film bulk acoustic wave resonator mainly uses the longitudinal piezoelectric coefficient (d33) of the piezoelectric film to produce the piezoelectric effect, so its main working mode is the longitudinal wave mode in the thickness direction (Thickness Extensional Mode, referred to as TE mode).

[0004] Ideally, a thin film bulk acoustic wave resonator only excites the thickness direction (TE) mode, but in addition to the desired TE mode, transverse parasitic modes such as Rayleigh-Lamb mode acoustic waves are also generated. These transverse mode waves will be lost at the boundary of the resonator, resulting in the loss of energy of the longitudinal mode required by the resonator, which ultimately leads to a decrease in the Q value of the resonator. In order to suppress the leakage of transverse mode acoustic waves at the edge of the resonator, a frame structure (including a convex structure and a concave structure) is generally added to the edge of the top electrode of the resonator, so as to confine the transverse mode acoustic waves within the effective area of ​​the resonator to prevent leakage. However, when the resonator is working, since the frame structure is connected to the top electrode, when a voltage is applied to the top electrode and the bottom electrode of the resonator, in addition to the main resonance generated by the main part of the resonator under the piezoelectric effect of the piezoelectric material, a secondary resonance will also be generated in the frame structure. Because the resonant frequency of the secondary resonance is different from the main resonance, it will affect the performance of the filter, as shown in Figure 1 (A). In the figure, Rm represents the secondary resonance and SW1 represents the parasitic mode. The larger their peak heights, the greater the negative impact on the performance of the resonator and the filter.

[0005] In order to solve this problem, the prior art separates the frame structure from the top electrode, that is, there is an air gap structure as shown in FIG1(B) and 15. In FIG1, 10 is the cavity structure at the bottom of the resonator, 11 is the bottom electrode, 12 is the piezoelectric layer, 13 is the top electrode, 14 is the protrusion structure, and 15 is the air gap structure between the protrusion structure and the top electrode. The existence of the air gap structure 15 can eliminate the sub-resonance in the protrusion structure. However, the existence of this structure will lead to a decrease in the Rp value of the resonator. At the same time, it is not easy to achieve during the processing process, and alignment deviation will easily occur when the gap is formed. Summary of the invention

[0006] The present invention is proposed to alleviate or solve at least one aspect of the above-mentioned problems in the prior art.

[0007] According to one aspect of an embodiment of the present invention, a bulk acoustic wave resonator is provided, comprising:

[0008] substrate;

[0009] Acoustic mirror;

[0010] A bottom electrode disposed above the substrate;

[0011] a top electrode having an electrode connection; and

[0012] a piezoelectric layer disposed above the bottom electrode and between the bottom electrode and the top electrode,

[0013] in:

[0014] The resonator further comprises an additional structure, wherein the additional structure is arranged at an edge of the top electrode and a gap is formed between the top electrode and the additional structure;

[0015] The resonator further comprises a layer of non-conductive material filling the gap and covering at least a portion of the additional structure and / or at least a portion of the top electrode.

[0016] Optionally, the non-conductive material layer covers the additional structure and the top electrode from above the additional structure and the top electrode. Further optionally, the non-conductive material layer completely covers the top electrode and the additional structure. Further, the non-conductive material layer can be a passivation layer. In an optional embodiment, the non-conductive material layer forms a depression at the gap. Alternatively, the top surface of the non-conductive material layer is flush.

[0017] Optionally, the lower side of the additional structure has a first gap, the lower side of the edge of the top electrode has a second gap, the first gap, the second gap and the gap form an inverted T-shaped gap structure; and the non-conductive material layer at least fills the space corresponding to the lateral part of the gap structure. Further optionally, the additional structure is a first convex structure, the edge of the top electrode is provided with a second convex structure; and the bridging width of the first convex structure and the bridging width of the second convex structure are both within the range of 1-3μm.

[0018] Optionally, a top electrode protrusion structure is provided at the edge of the top electrode, and the gap is formed between the top electrode protrusion structure and the additional structure. Further, the additional structure is a protrusion structure; and the thickness of the protrusion structure of the top electrode is the same as the thickness of the protrusion structure of the additional structure.

[0019] Optionally, the additional structure is a protruding structure.

[0020] Optionally, the width of the additional structure is greater than 2 μm, and further, greater than 5 μm.

[0021] Optionally, the additional structure is a combination of a convex structure and a concave structure, wherein the concave structure of the additional structure is on the inner side of the convex structure of the additional structure. Further, the non-conductive material layer completely covers the top electrode and the additional structure. Alternatively, the thickness of the concave structure of the additional structure is the same as the thickness of the top electrode; and the width of the concave structure of the additional structure is in the range of 1-3 μm.

[0022] Optionally, the width of the gap is in the range of 0.1 μm-0.5 μm. Further, the width of the gap may be 0.1-2 μm.

[0023] An embodiment of the present invention further relates to a bulk acoustic wave resonator, comprising:

[0024] substrate;

[0025] Acoustic mirror;

[0026] A bottom electrode disposed above the substrate;

[0027] a top electrode having an electrode connection; and

[0028] a piezoelectric layer disposed above the bottom electrode and between the bottom electrode and the top electrode,

[0029] in:

[0030] The resonator further comprises an additional structure, wherein the additional structure is arranged at an edge of the top electrode and a gap is formed between the top electrode and the additional structure;

[0031] The resonator further includes a non-conductive material layer, which covers the gap and also covers at least a portion of the additional structure on both sides of the gap and at least a portion of the top electrode.

[0032] An embodiment of the present invention further relates to a filter, comprising the above-mentioned BAW resonator.

[0033] An embodiment of the present invention also relates to an electronic device, comprising the above-mentioned filter or the above-mentioned resonator.

[0034] The technical solution of the present invention is helpful to ensure a high Q value and Rp value of the resonator while effectively eliminating the sub-resonance effect therein, thereby effectively improving the performance of the resonator and the filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following description and accompanying drawings may better help understand these and other features and advantages of various embodiments disclosed by the present invention, in which the same reference numerals always represent the same components, wherein:

[0036] Figure 1A Schematic diagram of sub-resonance generation in a resonator;

[0037] Figure 1B is a cross-sectional schematic diagram of a bulk acoustic wave resonator in the prior art;

[0038] Figure 2A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0039] Figure 2B is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0040] Figure 2C is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0041] Figure 3 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0042] Figure 4A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0043] Figure 4B is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0044] Figure 5A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0045] Figure 5Bis a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

[0046] Figure 6 It is a schematic diagram of simulation results of the Rp value of a BAW resonator in the prior art changing with the width of the gap between the protruding structure and the top electrode, wherein simulation results of the connection between the protruding structure and the top electrode and simulation results of the protruding structure and the top electrode with different gap widths are shown;

[0047] Figure 7 Schematic diagram of simulation results of the relationship between the width of the protruding structure and the Rp value in BAW resonators with different structures, which shows the situation where the protruding structure is connected to the top electrode, the situation where there is a gap between the protruding structure and the top electrode but no coverage, and the situation where there is a gap between the protruding structure and the top electrode and the non-conductive dielectric layer fills the gap and covers the protruding structure and the top electrode;

[0048] Figure 8 A schematic diagram of simulation results showing the influence of different gap widths on the Rp value;

[0049] Fig. 9 A schematic diagram of simulation results showing the influence of the filling method of non-conductive material on the Rp value;

[0050] Fig.10 Figure a) shows a frequency (Freq.) impedance (Mag.) curve of a BAW resonator with a conventional structure, Figure b) shows a frequency impedance curve of a BAW resonator according to an exemplary embodiment of the present invention, Figure c) shows a simulation result diagram of a change in the Q value Qsw1 of a resonator (the protruding structure is separated from the top electrode and the non-conductive dielectric layer fills the gap and completely covers the protruding structure and the top electrode) within 60 MHz below the series resonator frequency, and Figure d) shows a simulation result diagram of a change in the Q value Qsw2 of a resonator (the protruding structure is separated from the top electrode and the non-conductive dielectric layer fills the gap and completely covers the protruding structure and the top electrode) within 190 MHz below Qsw1;

[0051] Fig.11 The schematic diagram of the simulation structure of the relationship between the width of the additional structure and Rp based on the different structures of the additional structure and the top electrode in the present invention is exemplified. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further specifically described below by examples and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0053] In the present invention, by changing the frame structure of the edge of the top electrode of the BAW resonator (i.e., the additional structure mentioned later, including a protruding structure or a protruding structure and a recessed structure), the acoustic wave energy of the lateral mode in the resonator can be confined to an effective area while being easy to process and implement, thereby ensuring the high Q value and Rp value of the resonator and effectively eliminating the sub-resonance effect therein, thereby effectively improving the performance of the resonator and the filter.

[0054] In the present invention, since there is a gap between the additional structure and the top electrode, they are electrically isolated.

[0055] The following exemplarily describes with reference to the accompanying drawings a BAW resonator according to an embodiment of the present invention, in which an additional structure is separated from a top electrode to form a gap, and a non-conductive material layer fills the gap and covers at least a portion of the additional structure and at least a portion of the top electrode.

[0056] Figure 2A FIG. 4 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. Figure 2A In the embodiment shown: 10 is an acoustic reflector structure of the resonator, which can be a cavity structure etched in the substrate or a cavity structure protruding upward, or a Bragg reflection structure or other acoustic wave reflection form. Figure 2A , which is a cavity structure etched in the substrate, and this is also applicable to other exemplary embodiments of the present invention. Figure 2A In the figure, 11 is the bottom electrode of the resonator; 12 is the piezoelectric layer of the resonator; 13 is the top electrode of the resonator; 14 is a protruding structure; 15 is the gap between the protruding structure and the top electrode, and the gap width may be typically 0.25 μm, with a preferred range of 0.1-0.5 μm, and a further optional range of 0.1-2 μm; 22 is a non-conductive dielectric layer, which fills the gap 15 and completely covers the protruding structure 14 and the top electrode 13.

[0057] exist Figure 2A In the embodiment shown, the presence of the protruding structure can play a role in acoustic coupling, that is, since the acoustic impedance in the protruding structure does not match the acoustic impedance in the effective area of ​​the resonator, the transmission of the sound wave at the boundary is discontinuous. Therefore, at the boundary, a part of the sound energy will be coupled and reflected into the effective excitation area, and converted into a piston sound wave mode perpendicular to the surface of the piezoelectric layer, so that the Q factor of the resonator is improved;

[0058] At the same time, since the protruding structure is electrically insulated from the top electrode and is completely covered by a non-conductive material, it can play an electrically isolating role. Therefore, when the resonator is working, there is no electric field in the piezoelectric layer under the protruding structure, and no sub-resonance will be generated, so the influence of sub-resonant noise in the resonator can be effectively eliminated. In addition, the protruding structure and the top electrode are connected together by a non-conductive material, so compared with the air gap structure, it can further increase the effect of acoustic wave coupling, so its Rp value is higher than that of the prior art, that is, Figure 1 (B);

[0059] In addition, it is generally believed that the larger the width of the raised structure, the higher the Rp value. However, traditionally, parasitic modes and sub-resonances will also increase as the width of the raised structure increases. Through the design of this structure of the patent, the occurrence of sub-resonances can be avoided or reduced, and the intensity of parasitic modes can be weakened. Therefore, a large-width raised structure can be used to greatly increase the Rp value, and sub-resonances will not appear or will be reduced. Preferably, the width of the raised structure is much larger than 2μm, and can be further larger than 5μm.

[0060] Figure 2B FIG. 1 is a cross-sectional schematic diagram of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. Figure 2A The structures are similar, except that when the width of the air gap structure 15 is wider, a pit shape will be formed on the upper surface of the air gap (ie, the gap) during the process of forming the non-conductive dielectric layer 22 .

[0061] Figure 2C FIG. 1 is a cross-sectional schematic diagram of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. Figure 2A The structures are similar, except that the surface of the non-conductive dielectric layer 22 is smooth and flat, and can be processed by chemical mechanical polishing.

[0062] Figure 3 FIG. 1 is a cross-sectional schematic diagram of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. Figure 2A The structures are similar, except that there is an additional recessed structure 31 around the top electrode. In this embodiment, the thickness of the recessed structure is less than that of the top electrode. The presence of the recessed structure can increase the Qsw value of the resonator, effectively suppress the parasitic mode in the resonator, and further improve the performance of the resonator.

[0063] Figure 4A FIG. 4 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. Figure 4AIn the figure, 10 is the acoustic reflector structure of the resonator; 11 is the bottom electrode of the resonator; 21 is the flat layer located on both sides of the bottom electrode; 12 is the piezoelectric layer of the resonator; 13 is the top electrode of the resonator; 14 is a protruding structure, and a concave structure is arranged inside the protruding structure 14; 15 is the gap between the protruding structure and the top electrode, and the gap width d2 is typically 0.25μm, which is located in the top electrode and has a distance d1 from the edge of the top electrode, which can typically be 1-3μm; 22 is a non-conductive dielectric layer, which fills the gap 15 and completely covers the protruding structure 14 and the top electrode 13. Figure 4A In the embodiment of the present invention, it can be considered that the thickness of the recessed structure of the additional structure is the same as the thickness of the top electrode.

[0064] The manufacturing process of the gap 15 is mainly formed by photolithography and etching, that is, firstly, the pattern on the mask is transferred to the photoresist on the surface of the top electrode by photolithography, and then the thin film material at the gap structure is etched cleanly by etching, and finally the photoresist is removed to form a gap. In the photolithography process, in the process of transferring the pattern on the mask to the photoresist, the problem of alignment offset will occur, that is, the alignment mark on the mask and the alignment mark on the substrate will be offset during the alignment process, so the position of the gap structure finally made will change. Fig.11 From the simulation results, it can be seen that when the gap is located on the protruding structure, that is, case a), the performance of the resonator is better than when the gap is located on the top electrode, that is, case c).

[0065] If the conventional structure, i.e., no alignment offset structure is provided, an offset occurs during the processing, so that one gap is located on the protruding structure and the other gap is located in the top electrode structure, which will reduce the performance of the device. However, through the design of this structure, even if an alignment offset occurs during the processing, the final structure of the resonator will not be changed, and thus its performance will not be affected.

[0066] Figure 4B FIG. 1 is a cross-sectional schematic diagram of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. Figure 4A The structures are similar, except that the gap 15 is located in the protruding structure 14 and is at a distance d2 from the edge of the top electrode. Figure 4B In the embodiment, a convex structure is provided at an edge of the top electrode, and the convex structure of the top electrode and the convex structure as the additional structure are spaced apart from each other.

[0067] Figure 5A FIG. 4 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. Figure 5AIn the figure, 10 is the acoustic reflector structure of the resonator; 11 is the bottom electrode of the resonator; 12 is the piezoelectric layer of the resonator; 13 is the top electrode of the resonator; 14 is the protruding structure; 51 is the non-conductive dielectric layer (composed of non-conductive material), and the protruding structure 14 and the top electrode 13 both span across the two ends of the non-conductive material layer 15 and are not connected. Among them, the width d3 of the gap can be typically 0.25μm, and the width d2 of the top electrode spanning the non-conductive dielectric layer and the width d1 of the protruding structure spanning the non-conductive dielectric layer can be 1-3μm. The design of this structure can effectively prevent the influence of alignment offset on device performance during the processing process.

[0068] Figure 5B FIG. 4 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. Figure 5B In the embodiment shown, the gap 15 is filled with a non-conductive dielectric material and covers the recessed structure 31 and a portion of the top electrode 13. In this embodiment, the thickness of the recessed structure is smaller than the thickness of the top electrode. This structural design can effectively prevent the alignment offset from affecting the device performance during the processing.

[0069] Figure 6 Schematic diagram of simulation results of the Rp value of the BAW resonator in the prior art varying with the width of the gap between the protruding structure and the top electrode, wherein the Reference line is the simulation result of the connection between the protruding structure and the top electrode, and the rest are the cases where there is a gap between the protruding structure and the top electrode. Figure 6 In the figure, the ordinate represents the Rp value of the resonator, and the abscissa represents the width of the protruding structure. Figure 6 It can be seen that when the gap between the protruding structure and the top electrode increases from 0 to 2 μm, its Rp value decreases from 4100 to about 1500, that is, the greater the distance between the protruding structure and the top electrode, the worse the Rp value.

[0070] Figure 7 The figure is a schematic diagram of the simulation results of the relationship between the width of the protruding structure and the Rp value in BAW resonators with different structures, which shows the situation where the protruding structure is connected to the top electrode, the situation where there is a gap between the protruding structure and the top electrode but there is no coverage, and the situation where there is a gap between the protruding structure and the top electrode and the passivation layer fills the gap and covers the protruding structure and the top electrode. Figure 7The resonators with different structures are simulated in the figure, and the three simulation results correspond to the three structures shown in the right figure. It can be seen from the figure that, compared with the case where the protruding structure is connected to the top electrode, the Rp value of the resonator will deteriorate when the protruding structure is separated from the top electrode, that is, the performance of the resonator with the protruding structure separated from the top electrode is worse than that with the protruding structure connected to the top electrode; and when the protruding structure and the top electrode are completely covered with non-conductive material and the gap between them is filled, the Rp value of the resonator can be improved, that is, the performance of the resonator with the non-conductive material filling the gap and completely covering the protrusion and the top electrode is better than that with the protruding structure connected to the top electrode.

[0071] Figure 8 The figure is a schematic diagram of simulation results showing the effect of different gap widths on the Rp value. When a passivation layer is formed on the top of the device and fills the gap between the protruding structure and the top electrode, a simulation is performed to verify whether the gap size will affect the performance of the resonator. Figure 8 It can be seen that when the gap width increases from 0.25μm to 0.5μm, 1μm, 1.5μm, and 2μm, the Rp value gradually decreases. Therefore, the gap between the protruding structures is not as large as possible, and its maximum value is around 0.25μm.

[0072] Fig. 9 Schematic diagram of simulation results showing the effect of the filling method of non-conductive material on the Rp value. Fig. 9 It can be seen that when the non-conductive material is used to fill only the gap between the protruding structure and the top electrode, although the Rp value of the resonator can be improved, the effect is not as good as completely covering the protruding structure and the top electrode with the non-conductive material and filling the gap between them.

[0073] Fig.10 Figure a) shows the frequency impedance curve of a BAW resonator of a conventional structure, Figure b) shows the frequency impedance curve of a BAW resonator according to an exemplary embodiment of the present invention, Figure c) shows a schematic diagram of the simulation results of Qsw1, and Figure d) shows a schematic diagram of the simulation results of Qsw2. In the resonator impedance frequency curve, the change in the resonator Q value within 60MHz below the series resonator frequency is Qsw1, and the change in the resonator Q value within 190MHz below Qsw1 is Qsw2. Among them, the change in the resonator Q value in Qsw1 and Qsw2 represents the strength of the parasitic mode and sub-resonance in the resonator, respectively, and the higher the Q value, the weaker the strength.

[0074] exist Fig.10In a), it can be seen that the resonator of the traditional structure has obvious noise in Qsw1 and Qsw2. When the protruding structure is separated from the top electrode and the gap is filled with non-conductive material and covers the protruding structure and the top electrode, the simulation results are shown in Figures c) and d). It can be seen that its Qsw1 and Qsw2 are much higher than the traditional structure where the protruding structure is connected to the top electrode, that is, the parasitic mode and sub-resonance noise are significantly suppressed, as shown in Figure b).

[0075] It should be noted that, in the present invention, filling the gap not only includes Figure 2A -2C, Figure 3 , Figure 4A -4B, Figure 5B The filling situation shown also includes Figure 5A The filling situation shown, in addition Figure 5A In the embodiment, the vertical gaps may also be filled, which are all within the protection scope of the present invention.

[0076] In addition, although not shown, the present invention may also only cover at least a portion of the additional structure or at least a portion of the top electrode, which also produces a favorable technical effect compared to the situation in the prior art where only the gap is filled without covering the additional structure and the edge of the top electrode on both sides of the gap.

[0077] In addition, although not shown, the present invention can also cover the gap while also covering at least a portion of the additional structure on both sides of the gap and at least a portion of the top electrode, which also produces a favorable technical effect compared to the situation in the prior art where only the gap is filled without covering the additional structure on both sides of the gap and the edge of the top electrode.

[0078] Based on the above, the present invention proposes a bulk acoustic wave resonator, comprising:

[0079] substrate;

[0080] Acoustic mirror;

[0081] A bottom electrode disposed above the substrate;

[0082] a top electrode having an electrode connection; and

[0083] a piezoelectric layer disposed above the bottom electrode and between the bottom electrode and the top electrode,

[0084] in:

[0085] The resonator further comprises an additional structure, wherein the additional structure is arranged at an edge of the top electrode and a gap is formed between the top electrode and the additional structure;

[0086] The resonator further comprises a layer of non-conductive material filling the gap and covering at least a portion of the additional structure and / or at least a portion of the top electrode.

[0087] The present invention also provides a bulk acoustic wave resonator, comprising:

[0088] substrate;

[0089] Acoustic mirror;

[0090] A bottom electrode disposed above the substrate;

[0091] a top electrode having an electrode connection; and

[0092] a piezoelectric layer disposed above the bottom electrode and between the bottom electrode and the top electrode,

[0093] in:

[0094] The resonator further comprises an additional structure, wherein the additional structure is arranged at an edge of the top electrode and a gap is formed between the top electrode and the additional structure;

[0095] The resonator further includes a non-conductive material layer, which covers the gap and also covers at least a portion of the additional structure on both sides of the gap and at least a portion of the top electrode.

[0096] Fig.11 The schematic diagram of the simulation structure of the relationship between the width of the additional structure and Rp based on the different structures of the additional structure and the top electrode in the present invention is exemplified. Fig.11 Case a) corresponds to Figure 4B Case b) corresponds to Figure 2A Case c) corresponds to Figure 4A From Fig.11 It can be seen that Figure 4B The best situation is Figure 2A Secondly, Figure 4A Secondly.

[0097] In the present invention, the electrode composition material can be formed of gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), titanium tungsten (TiW), aluminum (Al), titanium (Ti) and other similar metals.

[0098] The piezoelectric layer material may be aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz (Quartz), potassium niobate (KNbO3) or lithium tantalate (LiTaO3) and the like.

[0099] The material of the non-conductive dielectric layer can be composed of non-conductive materials such as silicon dioxide, aluminum nitride, silicon nitride, silicon carbide, resin, rubber, etc.

[0100] Although not shown, an embodiment of the present invention also relates to a filter including the above-mentioned BAW resonator.

[0101] An embodiment of the present invention also relates to an electronic device, comprising the above-mentioned resonator or the above-mentioned filter.

[0102] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A bulk acoustic wave resonator, comprising: substrate; Acoustic mirror; A bottom electrode disposed above the substrate; a top electrode having an electrode connection portion; and a piezoelectric layer disposed above the bottom electrode and between the bottom electrode and the top electrode, in: The resonator further comprises an additional structure, wherein the additional structure is arranged at an edge of the top electrode and a gap is formed between the top electrode and the additional structure; The resonator further comprises a layer of non-conductive material filling the gap and covering at least a portion of the additional structure and / or at least a portion of the top electrode; The additional structure is a combination of a convex structure and a concave structure, wherein the concave structure of the additional structure is located inside the convex structure of the additional structure.

2. The resonator according to claim 1, wherein: The non-conductive material layer covers the additional structure and the top electrode from above the additional structure and the top electrode.

3. The resonator of claim 2, wherein: The non-conductive material layer completely covers the top electrode and the additional structure.

4. The resonator of claim 3, wherein: The non-conductive material layer is a passivation layer.

5. The resonator of claim 1, wherein: The additional structure has a width greater than 2 μm.

6. The resonator of claim 5, wherein: The additional structure has a width greater than 5 μm.

7. The resonator of claim 1, wherein: The thickness of the recessed structure of the additional structure is the same as the thickness of the top electrode; and The width of the recessed structure of the additional structure is in the range of 1-3 μm.

8. The resonator according to any one of claims 1 to 7, wherein: The width of the gap is in the range of 0.1 μm-2 μm.

9. The resonator of claim 8, wherein: The width of the gap is in the range of 0.1-0.5 μm.

10. A bulk acoustic wave resonator, comprising: substrate; Acoustic mirror; A bottom electrode disposed above the substrate; a top electrode having an electrode connection portion; and a piezoelectric layer disposed above the bottom electrode and between the bottom electrode and the top electrode, in: The resonator further comprises an additional structure, wherein the additional structure is arranged at an edge of the top electrode and a gap is formed between the top electrode and the additional structure; The resonator further comprises a layer of non-conductive material filling the gap and covering at least a portion of the additional structure and / or at least a portion of the top electrode; The lower side of the additional structure has a first gap, and the lower side of the edge of the top electrode has a second gap. The first gap, the second gap and the gap form an inverted T-shaped gap structure, and the non-conductive material layer at least fills the space corresponding to the lateral part of the gap structure.

11. The resonator of claim 10, wherein: The additional structure is a first protruding structure, and a second protruding structure is disposed on the edge of the top electrode; and A width of the first protruding structure across the non-conductive material layer and a width of the second protruding structure across the non-conductive material layer are both in the range of 1-3 μm.

12. The resonator of claim 10, wherein: A top electrode protrusion structure is disposed at the edge of the top electrode, and the gap is formed between the top electrode protrusion structure and the additional structure.

13. The resonator of claim 10, wherein: The non-conductive material layer completely covers the top electrode and the additional structure.

14. The resonator of claim 13, wherein: The non-conductive material layer is a passivation layer.

15. The resonator according to any one of claims 10 to 14, wherein: The additional structure has a width greater than 2 μm.

16. The resonator of claim 15, wherein: The additional structure has a width greater than 5 μm.

17. The resonator according to any one of claims 10 to 14, wherein: The width of the gap is in the range of 0.1 μm-2 μm.

18. The resonator of claim 17, wherein: The width of the gap is in the range of 0.1-0.5 μm.

19. A filter comprising the BAW resonator according to any one of claims 1 to 18.

20. An electronic device comprising the filter according to claim 19 or the resonator according to any one of claims 1-18.

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