Bulk acoustic wave resonator, bulk acoustic wave filter

Abstract

A bulk acoustic wave resonator device includes: a first layer, the first layer includes a cavity located on a first side; a first electrode layer, located in the cavity; a second layer, located on the first side and on the first electrode layer, the second layer is a flat layer, covering the cavity; and a second electrode layer, located on the first side and on the second layer, wherein the first electrode layer includes at least two first electrode strips or the second electrode layer includes at least two second electrode strips. The embodiment of the present invention enhances the difference in acoustic impedance between the resonant region and the non-resonant region, thereby improving the Q value of the resonant device. In addition, the piezoelectric layer may not include grains with obvious turning, thereby helping to improve the electromechanical coupling coefficient and Q value of the resonant device. In addition, when forming the electrode layer, the operating frequency of the resonant device can be controlled by adjusting the width of at least two first electrode strips or at least two second electrode strips or the spacing distance between two adjacent first electrode strips or two second electrode strips.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a bulk acoustic wave resonator device and a bulk acoustic wave filter device. Background Art

[0002] The RF (Radio Frequency, RF) front-end chips of wireless communication equipment include power amplifiers, antenna switches, RF filters, duplexers, multiplexers and low noise amplifiers. Among them, RF filters include surface acoustic wave (SAW) filters, bulk acoustic wave (BAW) filters, micro-electro-mechanical system (MEMS) filters, integrated passive devices (IPD) filters, etc. The quality factor value (Q value) of SAW resonators and BAW resonators is relatively high. The low insertion loss and high out-of-band suppression RF filters made of SAW resonators and BAW resonators, namely SAW filters and BAW filters, are the mainstream RF filters used in wireless communication equipment such as mobile phones and base stations. Among them, the Q value is the quality factor value of the resonator, which is defined as the center frequency divided by the 3dB bandwidth of the resonator. The operating frequency of SAW filters is generally 0.4GHz to 2.7GHz, and the operating frequency of BAW filters is generally 0.7GHz to 7GHz.

[0003] Compared with SAW resonators, BAW resonators have better performance, but due to the complex process steps, the manufacturing cost of BAW resonators is higher than that of SAW resonators. However, as wireless communication technology gradually evolves, more and more frequency bands are used. At the same time, with the application of frequency band superposition technologies such as carrier aggregation, the mutual interference between wireless frequency bands has become more and more serious. High-performance BAW technology can solve the problem of mutual interference between frequency bands. With the advent of the 5G era, wireless mobile networks have introduced higher communication frequency bands. Currently, only BAW technology can solve the filtering problem of high-frequency bands.

[0004] Figure 1aA BAW filter circuit is shown, including a ladder circuit composed of multiple BAW resonators, wherein f1, f2, f3, and f4 represent four different frequencies, respectively. In each BAW resonator, the metal electrodes on both sides of the piezoelectric layer of the resonator generate alternating positive and negative voltages, and the piezoelectric layer generates sound waves through the alternating positive and negative voltages. The sound waves in the resonator propagate in a direction perpendicular to the piezoelectric layer. In order to form resonance, the sound wave needs to be totally reflected at the upper surface of the upper metal electrode and the lower surface of the lower metal electrode to form a standing sound wave. The condition for the reflection of the sound wave is that the acoustic impedance of the contact area with the upper surface of the upper metal electrode and the lower surface of the lower metal electrode is significantly different from the acoustic impedance of the metal electrode.

[0005] Film Bulk Acoustic Wave Resonator (FBAR) is a BAW resonator that can confine the energy of acoustic waves within the device. The resonator has air above the resonance area and a cavity below. The acoustic impedance of air is quite different from that of metal electrodes, so the acoustic waves can be fully reflected on the upper surface of the upper metal electrode and the lower surface of the lower metal electrode, forming standing waves.

[0006] Figure 1b A schematic diagram of the cross-section A structure of an FBAR 100 is shown. The FBAR 100 includes: a substrate 101, the substrate 101 includes a cavity 101a; and an active layer 103, which is located on the substrate 101. The active layer 103 includes a piezoelectric layer 105 and electrode layers 107 (i.e., a lower electrode layer) and 109 (i.e., an upper electrode layer) respectively located on both sides of the piezoelectric layer 105, wherein the electrode layer 107 contacts the substrate 101. The resonance region 111 on the active layer 103 has an overlapped portion with the substrate 101, so the resonance region 111 is not suspended relative to the cavity 101a. If the acoustic impedance of the resonance region 111 is similar to that of the non-resonance region, the energy of the resonance region 111 will diffuse to the non-resonance region, thereby causing the Q value of the resonator to decrease. In addition, since the electrode layer 107 is raised, forming the piezoelectric layer 105 directly on the electrode layer 107 will cause some crystals in the piezoelectric layer 105 (for example, crystals at both edges of the piezoelectric layer 105 in the horizontal direction) to turn significantly and become non-parallel to other crystals, thereby reducing the electromechanical coupling coefficient and Q value of the FBAR. In addition, after the electrode layer 109 is formed, the thickness of the electrode layer needs to be adjusted to control the frequency of the resonator. Summary of the invention

[0007] The problem solved by the present invention is to provide a bulk acoustic wave resonator, wherein the resonant region of the bulk acoustic wave resonator is suspended relative to the cavity on the intermediate layer or the support layer or the substrate, which can enhance the difference in acoustic impedance between the resonant region and the non-resonant region, thereby enhancing the Q value of the resonant device. In addition, the piezoelectric layer of the bulk acoustic wave resonator does not include crystals with obvious turning, thereby contributing to enhancing the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device. In addition, when forming the electrode layer, the frequency of the resonant device can be controlled by adjusting the width of the plurality of electrode strips or the spacing distance between two adjacent electrode strips.

[0008] To solve the above problems, an embodiment of the present invention provides a bulk acoustic wave resonance device, comprising: a first layer, the first layer including a cavity located on a first side; a first electrode layer located in the cavity; a second layer, located on the first side and on the first electrode layer, the second layer being a flat layer, covering the first cavity; and a second electrode layer, located on the first side and on the second layer, wherein the first electrode layer includes at least two first electrode strips or the second electrode layer includes at least two second electrode strips.

[0009] It should be noted that by adjusting the positions of the first electrode layer and the second electrode layer so that there is no overlapping contact portion between the resonance region and the first layer, the resonance region is suspended relative to the first cavity, which can increase the difference in acoustic impedance between the resonance region and the non-resonance region and improve the Q value of the resonance device. In addition, when forming the electrode layer, the frequency of the resonance device can be controlled by adjusting the width of the at least two first electrode strips or the at least two second electrode strips or the spacing between two adjacent first electrode strips or two second electrode strips.

[0010] In some embodiments, the first electrode layer comprises a first polarity and the second electrode layer comprises a second polarity. In some embodiments, the at least two first electrode strips comprise the first polarity. In some embodiments, the at least two second electrode strips comprise the second polarity.

[0011] In some embodiments, the first electrode layer includes a first polarity and a second polarity, and the second electrode layer includes the first polarity and the second polarity. In some embodiments, the at least two first electrode strips include the first polarity and the second polarity, and the at least two second electrode strips include the first polarity and the second polarity, wherein the first electrode strips and the second electrode strips corresponding to the two sides of the second layer include the first polarity and the second polarity, respectively. In some embodiments, the first polarity and the second polarity are arranged alternately.

[0012] In some embodiments, the at least two first electrode strips include at least one first duty factor, and the value range of the at least one first duty factor includes but is not limited to 0.1 to 1. It should be noted that the duty factor is defined as the value obtained by dividing the width of the electrode strip by the spacing distance between two adjacent electrode strips. In some embodiments, the at least two second electrode strips include at least one second duty factor, and the value range of the at least one second duty factor includes but is not limited to 0.1 to 1.

[0013] In some embodiments, the spacing distance between two adjacent first electrode strips is consistent, including the first distance. In some embodiments, the spacing distance between two adjacent second electrode strips is consistent, including the second distance.

[0014] In some embodiments, the spacing distance between two adjacent first electrode strips varies, including at least a third distance and a fourth distance. In some embodiments, the spacing distance between two adjacent second electrode strips varies, including at least a fifth distance and a sixth distance.

[0015] In some embodiments, the widths of the at least two first electrode strips are consistent, including the first width. In some embodiments, the widths of the at least two second electrode strips are consistent, including the second width.

[0016] In some embodiments, the widths of the at least two first electrode strips vary, including at least a third width and a fourth width. In some embodiments, the widths of the at least two second electrode strips vary, including at least a fifth width and a sixth width.

[0017] In some embodiments, a portion of the second electrode layer that overlaps with the first electrode layer is located above the cavity, and a projection of the overlapping portion perpendicular to the first layer is located within the cavity.

[0018] In some embodiments, the material of the first electrode layer includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the second electrode layer includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0019] In some embodiments, the first layer further includes: an intermediate layer, the intermediate layer including the cavity. In some embodiments, the material of the intermediate layer includes but is not limited to at least one of the following: a polymer, an insulating dielectric. In some embodiments, the polymer includes but is not limited to at least one of the following: benzocyclobutene, a photosensitive epoxy resin photoresist, and a polyimide. In some embodiments, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide. In some embodiments, the thickness of the intermediate layer includes but is not limited to: 0.1 microns to 10 microns.

[0020] In some embodiments, the first layer further includes: a support layer, the support layer including the first cavity. In some embodiments, the material of the support layer includes but is not limited to at least one of the following: a polymer, an insulating dielectric. In some embodiments, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), a photosensitive epoxy resin photoresist (e.g., SU-8), and polyimide. In some embodiments, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide. In some embodiments, the thickness of the support layer includes but is not limited to: 20 microns to 100 microns.

[0021] In some embodiments, the first layer further comprises: a first substrate, the first substrate comprising the cavity. In some embodiments, the material of the first substrate includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0022] In some embodiments, the first layer also includes: an etching shielding layer, which at least covers the bottom or sidewall of the cavity. In some embodiments, the material of the etching shielding layer includes but is not limited to at least one of the following: aluminum nitride, silicon carbide, diamond, silicon nitride, silicon dioxide, aluminum oxide, titanium dioxide. In some embodiments, the thickness of the etching shielding layer includes but is not limited to: 0.1 micron to 3 microns. In other embodiments, the thickness of the etching shielding layer includes but is not limited to: 2 microns to 6 microns. It should be noted that the etching shielding layer can protect the intermediate layer or the supporting layer or the first substrate when etching to form the cavity. In addition, the etching shielding layer can protect the resonance device from corrosion by water and oxygen.

[0023] In some embodiments, the second layer includes: a piezoelectric layer, the piezoelectric layer includes a plurality of crystals, the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals; a first coordinate axis along the first direction corresponds to the height of the first crystal, and a second coordinate axis along the second direction corresponds to the height of the second crystal, wherein the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means: the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means: the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0024] In some embodiments, the first crystal corresponds to a first coordinate system, which includes the first coordinate axis and a third coordinate axis along a third direction; the second crystal corresponds to a second coordinate system, which includes the second coordinate axis and a fourth coordinate axis along a fourth direction.

[0025] In some embodiments, the first coordinate system further includes a fifth coordinate axis along a fifth direction, and the second coordinate system further includes a sixth coordinate axis along a sixth direction.

[0026] In some embodiments, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0027] In some embodiments, the material of the piezoelectric layer includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0028] In some embodiments, the second layer includes: a piezoelectric layer, the piezoelectric layer includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to indicate the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the half-peak width (Full Width at Half Maximum, FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0029] It should be noted that forming the piezoelectric layer on a plane can make the piezoelectric layer not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0030] In some embodiments, the resonant device further comprises: a second substrate, located on a second side of the first layer, the second side being opposite to the first side. In some embodiments, the material of the second substrate includes but is not limited to at least one of the following: silicon, silicon carbide, and glass. It should be noted that the acoustic impedance of the first layer may be small, thereby preventing sound waves from leaking from the resonance region into the second substrate.

[0031] In some embodiments, the resonant device further comprises: a thin film located between the first layer and the second substrate. In some embodiments, the thin film includes but is not limited to: a polycrystalline thin film. In some embodiments, the material of the polycrystalline thin film includes but is not limited to at least one of the following: polycrystalline silicon, polycrystalline silicon nitride, polycrystalline silicon carbide. It should be noted that the thin film helps to prevent the formation of a free electron layer on the surface of the second substrate, thereby reducing the electrical loss caused by the second substrate.

[0032] An embodiment of the present invention further provides a bulk acoustic wave filter device, comprising: a bulk acoustic wave resonance device provided by at least one of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1a is a schematic diagram of a bulk acoustic wave filter circuit;

[0034] Figure 1b is a schematic diagram of the structure of a cross section A of a FBAR 100;

[0035] Figure 2a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 200 according to an embodiment of the present invention;

[0036] Figure 2bis a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 200 according to an embodiment of the present invention;

[0037] Figure 3a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 300 according to an embodiment of the present invention;

[0038] Figure 3b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 300 according to an embodiment of the present invention;

[0039] Figure 4a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 400 according to an embodiment of the present invention;

[0040] Figure 4b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 400 according to an embodiment of the present invention;

[0041] Figure 5a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 500 according to an embodiment of the present invention;

[0042] Figure 5b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 500 according to an embodiment of the present invention;

[0043] Figure 6a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 600 according to an embodiment of the present invention;

[0044] Figure 6b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 600 according to an embodiment of the present invention;

[0045] Figure 7a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 700 according to an embodiment of the present invention;

[0046] Figure 7b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 700 according to an embodiment of the present invention;

[0047] Figure 8a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 800 according to an embodiment of the present invention;

[0048] Figure 8b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 800 according to an embodiment of the present invention;

[0049] Figure 9a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 900 according to an embodiment of the present invention;

[0050] Figure 9b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 900 according to an embodiment of the present invention;

[0051] Fig.10a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 1000 according to an embodiment of the present invention;

[0052] Fig.10b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 1000 according to an embodiment of the present invention;

[0053] Fig.11a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 1100 according to an embodiment of the present invention;

[0054] Fig.11b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 1100 according to an embodiment of the present invention;

[0055] Fig.12a is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 1200 according to an embodiment of the present invention;

[0056] Figure 12b is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 1200 according to an embodiment of the present invention;

[0057] Fig.13 It is a schematic diagram of the structure of a hexagonal crystal;

[0058] Fig.14 (i) is a schematic diagram of the structure of an orthorhombic crystal;

[0059] Fig.14 (ii) is a schematic diagram of the structure of a tetragonal crystal;

[0060] Fig.14 (iii) is a schematic diagram of the structure of a cubic crystal.

[0061] It should be noted that the section A and the section B are two sections that are orthogonal to each other. DETAILED DESCRIPTION

[0062] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0063] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0064] As described in the background section, see Figure 1b, the resonance zone 111 is not suspended relative to the cavity 101a, and has an overlapping portion with the substrate 101. If the acoustic impedance of the resonance zone 111 is similar to the acoustic impedance of the non-resonance zone, the energy of the resonance zone 111 will diffuse to the non-resonance zone, thereby reducing the Q value of the resonator. In addition, since the electrode layer 107 is raised, forming the piezoelectric layer 105 directly on the electrode layer 107 will cause some crystals in the piezoelectric layer 105 (for example, crystals at the edges of both sides of the piezoelectric layer 105 in the horizontal direction) to turn significantly and not be parallel to other crystals, thereby reducing the electromechanical coupling coefficient of the resonance device and the Q value of the resonance device. In addition, after the electrode layer 109 is formed, it is necessary to adjust the thickness of the electrode layer to control the frequency of the resonator.

[0065] The inventors of the present invention discovered that by adjusting the positions of the two electrode layers so that there is no overlapping contact between the resonance zone and the intermediate layer or the supporting layer or the first substrate, and the resonance zone is suspended relative to the cavity of the intermediate layer or the supporting layer or the first substrate, the difference in acoustic impedance between the resonance zone and the non-resonance zone can be improved, thereby improving the Q value of the resonance device.

[0066] The inventors of the present invention have also found that forming a piezoelectric layer on a plane can make the piezoelectric layer include no obvious turned crystals, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0067] The inventors of the present invention have also discovered that when forming the two electrode layers, the operating frequency of the resonant device can be controlled by adjusting the width of the plurality of electrode strips or the spacing distance between two adjacent electrode strips.

[0068] The inventors of the present invention have also discovered that the use of the intermediate layer having a smaller acoustic impedance than the piezoelectric layer can block the sound waves from leaking from the resonance region into the second substrate.

[0069] The inventors of the present invention have also found that disposing a thin film between the intermediate layer and the second substrate helps to prevent a free electron layer from being formed on the surface of the second substrate, thereby reducing the electrical loss caused by the second substrate.

[0070] An embodiment of the present invention provides a bulk acoustic wave resonance device, comprising: a first layer, the first layer including a cavity located on a first side; a first electrode layer located in the cavity; a second layer, located on the first side and on the first electrode layer, the second layer being a flat layer and covering the first cavity; and a second electrode layer, located on the first side and on the second layer, wherein the first electrode layer includes at least two first electrode strips or the second electrode layer includes at least two second electrode strips.

[0071] It should be noted that by adjusting the positions of the first electrode layer and the second electrode layer so that there is no overlapping contact portion between the resonance region and the first layer, the resonance region is suspended relative to the first cavity, which can increase the difference in acoustic impedance between the resonance region and the non-resonance region, thereby increasing the Q value of the resonance device. In addition, when forming the first electrode layer or the second electrode layer, the frequency of the resonance device can be controlled by adjusting the width of the at least two first electrode strips or the at least two second electrode strips or the spacing distance between two adjacent first electrode strips or two second electrode strips.

[0072] In some embodiments, the first electrode layer comprises a first polarity and the second electrode layer comprises a second polarity. In some embodiments, the at least two first electrode strips comprise the first polarity. In some embodiments, the at least two second electrode strips comprise the second polarity.

[0073] In some embodiments, the first electrode layer includes a first polarity and a second polarity, and the second electrode layer includes the first polarity and the second polarity. In some embodiments, the at least two first electrode strips include the first polarity and the second polarity, and the at least two second electrode strips include the first polarity and the second polarity, wherein the first electrode strips and the second electrode strips corresponding to the two sides of the second layer include the first polarity and the second polarity, respectively. In some embodiments, the first polarity and the second polarity are arranged alternately.

[0074] In some embodiments, the at least two first electrode strips include at least one first duty factor, and the value range of the at least one first duty factor includes but is not limited to 0.1 to 1. It should be noted that the duty factor is defined as the value obtained by dividing the width of the electrode strip by the spacing distance between two adjacent electrode strips. In some embodiments, the at least two second electrode strips include at least one second duty factor, and the value range of the at least one second duty factor includes but is not limited to 0.1 to 1.

[0075] In some embodiments, the spacing distance between two adjacent first electrode strips is consistent, including the first distance. In some embodiments, the spacing distance between two adjacent second electrode strips is consistent, including the second distance. In some embodiments, the distance between two adjacent first electrode strips is variable, including at least a third distance and a fourth distance. In some embodiments, the spacing distance between two adjacent second electrode strips is variable, including at least a fifth distance and a sixth distance.

[0076] In some embodiments, the widths of the at least two first electrode strips are consistent, including the first width. In some embodiments, the widths of the at least two second electrode strips are consistent, including the second width. In some embodiments, the widths of the at least two first electrode strips are variable, including at least a third width and a fourth width. In some embodiments, the widths of the at least two second electrode strips are variable, including at least a fifth width and a sixth width.

[0077] In some embodiments, a portion of the second electrode layer that overlaps with the first electrode layer is located above the cavity, and a projection of the overlapping portion perpendicular to the first layer is located within the cavity.

[0078] In some embodiments, the material of the first electrode layer includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the second electrode layer includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0079] In some embodiments, the first layer further includes: an intermediate layer, the intermediate layer including the cavity. In some embodiments, the material of the intermediate layer includes but is not limited to at least one of the following: a polymer, an insulating dielectric. In some embodiments, the polymer includes but is not limited to at least one of the following: benzocyclobutene, a photosensitive epoxy resin photoresist, and a polyimide. In some embodiments, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide. In some embodiments, the thickness of the intermediate layer includes but is not limited to: 0.1 microns to 10 microns.

[0080] In some embodiments, the first layer further includes: a support layer, the support layer including the first cavity. In some embodiments, the material of the support layer includes but is not limited to at least one of the following: a polymer, an insulating dielectric. In some embodiments, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), a photosensitive epoxy resin photoresist (e.g., SU-8), and polyimide. In some embodiments, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide. In some embodiments, the thickness of the support layer includes but is not limited to: 20 microns to 100 microns.

[0081] In some embodiments, the first layer further comprises: a first substrate, the first substrate comprising the cavity. In some embodiments, the material of the first substrate includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0082] In some embodiments, the first layer further includes: an etching shield layer, at least covering the bottom or sidewall of the cavity. In some embodiments, the material of the etching shield layer includes but is not limited to at least one of the following: aluminum nitride, silicon carbide, diamond, silicon nitride, silicon dioxide, aluminum oxide, titanium dioxide. In some embodiments, the thickness of the etching shield layer includes but is not limited to: 0.1 micron to 3 microns. In some embodiments, the thickness of the etching shield layer includes but is not limited to: 2 microns to 6 microns.

[0083] It should be noted that the etching shielding layer can protect the intermediate layer or the supporting layer or the first substrate when the cavity is formed by etching. In addition, the etching shielding layer can protect the resonance device from being corroded by water and oxygen.

[0084] In some embodiments, the second layer includes: a piezoelectric layer, the piezoelectric layer includes a plurality of crystals, the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals; a first coordinate axis along the first direction corresponds to the height of the first crystal, and a second coordinate axis along the second direction corresponds to the height of the second crystal, wherein the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means: the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means: the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0085] In some embodiments, the first crystal corresponds to a first coordinate system, which includes the first coordinate axis and a third coordinate axis along a third direction; the second crystal corresponds to a second coordinate system, which includes the second coordinate axis and a fourth coordinate axis along a fourth direction.

[0086] In some embodiments, the first coordinate system further includes a fifth coordinate axis along a fifth direction, and the second coordinate system further includes a sixth coordinate axis along a sixth direction. In some embodiments, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0087] In some embodiments, the material of the piezoelectric layer includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0088] In some embodiments, the second layer includes: a piezoelectric layer, the piezoelectric layer includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to indicate the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the half-peak width (Full Width at Half Maximum, FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0089] It should be noted that forming the piezoelectric layer on a plane can make the piezoelectric layer not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0090] In some embodiments, the resonant device further comprises: a second substrate, located on a second side of the first layer, the second side being opposite to the first side. In some embodiments, the material of the second substrate includes but is not limited to at least one of the following: silicon, silicon carbide, and glass. It should be noted that the acoustic impedance of the first layer may be small, thereby preventing sound waves from leaking from the resonance region into the second substrate.

[0091] In some embodiments, the resonant device further comprises: a thin film located between the first layer and the second substrate. In some embodiments, the thin film includes but is not limited to: a polycrystalline thin film. In some embodiments, the material of the polycrystalline thin film includes but is not limited to at least one of the following: polycrystalline silicon, polycrystalline silicon nitride, polycrystalline silicon carbide.

[0092] It should be noted that the thin film disposed between the intermediate layer and the second substrate helps to prevent a free electron layer from being formed on the surface of the second substrate, thereby reducing the electrical loss caused by the second substrate.

[0093] An embodiment of the present invention further provides a bulk acoustic wave filter device, comprising: a bulk acoustic wave resonance device provided by at least one of the above embodiments.

[0094] Figure 2a Schematic diagram of the cross-section A of a bulk acoustic wave resonance device 200 according to an embodiment of the present invention.

[0095] like Figure 2aAs shown, the embodiment of the present invention provides a bulk acoustic wave resonator 200 including: a substrate 201, wherein the upper surface side of the substrate 201 includes a cavity 201a; an electrode layer 203, wherein the first end of the cross section A of the electrode layer 203 contacts the side wall of the cavity 201a, and the second end of the cross section A of the electrode layer 203 is located in the cavity 201a; a piezoelectric layer 205, which is located on the substrate 201 and the electrode layer 203, and the piezoelectric layer 205 is a flat layer, covering the cavity 201a; and an electrode layer 207, which is located on the piezoelectric layer 205. Figure 2a It can be seen that the resonance region 209 (i.e., the overlapping region of the electrode layer 203 and the electrode layer 207) is suspended relative to the cavity 201a and has no overlapping contact portion with the substrate 201. The vertical projection of the resonance region 209 perpendicular to the upper surface is located within the cavity 201a, which can increase the difference in acoustic impedance between the resonance region 209 and the non-resonance region, thereby improving the Q value of the resonance device.

[0096] In this embodiment, the material of the substrate 201 includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0097] In this embodiment, the material of the piezoelectric layer 205 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0098] In this embodiment, the piezoelectric layer 205 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0099] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0100] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0101] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0102] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0103] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0104] In this embodiment, the piezoelectric layer 205 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0105] It should be noted that forming the piezoelectric layer 205 on a plane can make the piezoelectric layer 205 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0106] In this embodiment, the portion of the electrode layer 203 that overlaps with the electrode layer 207 is located in the cavity 201 a ; and the portion of the electrode layer 207 that overlaps with the electrode layer 203 is located above the cavity 201 a .

[0107] In this embodiment, the material of the electrode layer 203 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 207 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0108] In this embodiment, the electrode layer 203 includes a negative electrode, and the electrode layer 207 includes a positive electrode. In another embodiment, the electrode layer 203 includes a positive electrode, and the electrode layer 207 includes a negative electrode.

[0109] Figure 2b 2 is a schematic structural diagram of a cross-section B of a bulk acoustic wave resonance device 200 according to an embodiment of the present invention.

[0110] like Figure 2b As shown, the resonant device 200 includes: the substrate 201, the upper surface side of the substrate 201 includes the cavity 201a; the electrode layer 203, the cross section B of which is located in the cavity 201a; the piezoelectric layer 205, located on the substrate 201 and the electrode layer 203; and the electrode layer 207, located on the piezoelectric layer 205. Figure 2b It can be seen that the resonance region 209 (ie, the overlapping region of the electrode layer 203 and the electrode layer 207 ) is suspended relative to the cavity 201 a and has no overlapping contact portion with the substrate 201 .

[0111] Figure 3a Schematic diagram of the cross-section A of a bulk acoustic wave resonance device 300 according to an embodiment of the present invention.

[0112] like Figure 3a As shown, an embodiment of the present invention provides a bulk acoustic wave resonance device 300 including: a substrate 301, wherein the upper surface side of the cross section A of the substrate 301 includes a cavity 301a and a groove 301b, wherein the groove 301b is located on one side of the cavity 301a in the horizontal direction and communicates with the cavity 301a, and the depth of the groove 301b is less than the depth of the cavity 301a; an electrode layer 303, wherein the first end of the cross section A of the electrode layer 303 is located in the groove 301b, and the second end of the cross section A of the electrode layer 303 is located in the cavity 301a, wherein the depth of the groove 301b is equal to the thickness of the electrode 303; a piezoelectric layer 305, located on the substrate 301 and the electrode layer 303, the piezoelectric layer 305 is a flat layer, covering the cavity 301a; and an electrode layer 307, located on the piezoelectric layer 305. Figure 3a It can be seen that the resonance region 309 (i.e., the overlapping region of the electrode layer 303 and the electrode layer 307) is suspended relative to the cavity 301a, and has no overlapping contact portion with the substrate 301. Therefore, the vertical projection of the resonance region 309 perpendicular to the upper surface is located within the cavity 301a, which can increase the difference in acoustic impedance between the resonance region 309 and the non-resonance region, thereby improving the Q value of the resonance device.

[0113] In this embodiment, the material of the substrate 301 includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0114] In this embodiment, the piezoelectric layer 305 also covers the upper surface side. In this embodiment, the material of the piezoelectric layer 305 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0115] In this embodiment, the piezoelectric layer 305 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0116] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0117] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0118] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0119] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0120] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0121] In this embodiment, the piezoelectric layer 305 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to indicate the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function values ​​before and after a peak are equal to half of the peak value.

[0122] It should be noted that forming the piezoelectric layer 305 on a plane can make the piezoelectric layer 305 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0123] In this embodiment, the portion of the electrode layer 303 that overlaps with the electrode layer 307 is located in the cavity 301 a ; and the portion of the electrode layer 307 that overlaps with the electrode layer 303 is located above the cavity 301 a .

[0124] In this embodiment, the material of the electrode layer 303 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 307 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0125] In this embodiment, the electrode layer 303 includes a negative electrode, and the electrode layer 307 includes a positive electrode. In another embodiment, the electrode layer 303 includes a positive electrode, and the electrode layer 307 includes a negative electrode.

[0126] Figure 3b 1 is a schematic diagram of the cross-section B structure of a bulk acoustic wave resonance device 300 according to an embodiment of the present invention.

[0127] like Figure 3b As shown, the resonant device 300 includes: the substrate 301, the upper surface side of the cross section B of the substrate 301 includes the cavity 301a; the electrode layer 303 includes four electrode strips 303b, and the cross section B of the electrode layer 303 is located in the cavity 301a; the piezoelectric layer 305 is located on the substrate 301 and the electrode layer 303; and the electrode layer 307 is located on the piezoelectric layer 305. Figure 3b It can be seen that the resonance region 309 (ie, the overlapping region of the electrode layer 303 and the electrode layer 307 ) is suspended relative to the cavity 301 a and has no overlapping contact portion with the substrate 301 .

[0128] In this embodiment, the four electrode strips 303b include negative electrodes, and the electrode layer 307 includes positive electrodes. In another embodiment, the four electrode strips 303b include positive electrodes, and the electrode layer 307 includes negative electrodes.

[0129] In this embodiment, the spacing distance between two adjacent electrode strips 303b includes a first distance and a second distance, wherein the first distance is smaller than the second distance.

[0130] In this embodiment, the widths of the four electrode strips 303b are consistent, including the first width.

[0131] In this embodiment, the duty cycle of the four electrode strips 303b includes a first duty cycle corresponding to the first distance and the first width, and a second duty cycle corresponding to the second distance and the first width, wherein the value ranges of the first duty cycle and the second duty cycle include but are not limited to 0.1 to 1, and the first duty cycle is greater than the second duty cycle.

[0132] It should be noted that, when forming the electrode layer 303 , the operating frequency of the resonant device can be controlled by adjusting the first distance or the second distance or the first width.

[0133] In other embodiments, the number of electrodes included in the electrode layer 303 may be other even numbers, for example, 2, 6, 8, 10, 12, 14, 16, 18, 20, etc. In other embodiments, the number of electrodes included in the electrode layer 303 may be an odd number, for example, 3, 5, 7, 9, 11, 13, 15, 17, 19, etc.

[0134] Figure 4a 4 is a schematic diagram of the cross-section A of a bulk acoustic wave resonance device 400 according to an embodiment of the present invention.

[0135] like Figure 4a As shown, the embodiment of the present invention provides a bulk acoustic wave resonance device 400 including: a substrate 401, wherein the upper surface side of the substrate 401 includes a cavity 401a; an etching shielding layer 411, located in the cavity 401a, covering the bottom and side walls of the cavity 401a; an electrode layer 403, wherein the first end of the cross section A of the electrode layer 403 contacts the etching shielding layer 411, and the second end of the cross section A of the electrode layer 403 is located in the cavity 401a; a piezoelectric layer 405, located on the substrate 401 and the electrode layer 403, wherein the piezoelectric layer 405 is a flat layer, covering the cavity 401a; and an electrode layer 407, located on the piezoelectric layer 405. Figure 4a It can be seen that the resonance region 409 (i.e., the overlapping region of the electrode layer 403 and the electrode layer 407) is suspended relative to the cavity 401a, and has no overlapping contact portion with the substrate 401. The vertical projection of the resonance region 409 perpendicular to the upper surface is located within the cavity 401a, which can increase the difference in acoustic impedance between the resonance region 409 and the non-resonance region, thereby improving the Q value of the resonance device.

[0136] In this embodiment, the material of the substrate 401 includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0137] In this embodiment, the material of the etching shielding layer 411 includes but is not limited to at least one of the following: aluminum nitride, silicon carbide, diamond, silicon nitride, silicon dioxide, aluminum oxide, and titanium dioxide.

[0138] It should be noted that the etching shielding layer 411 can protect the substrate 401 when the cavity 401a is formed by etching. In addition, the etching shielding layer 411 can protect the resonance device from being corroded by water and oxygen.

[0139] In this embodiment, the thickness of the etching shielding layer 411 includes, but is not limited to, 0.1 micrometer to 3 micrometers. In another embodiment, the thickness of the etching shielding layer 411 includes, but is not limited to, 2 micrometers to 6 micrometers.

[0140] In this embodiment, the piezoelectric layer 405 also covers the upper surface side. In this embodiment, the material of the piezoelectric layer 405 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0141] In this embodiment, the piezoelectric layer 405 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0142] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0143] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0144] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0145] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0146] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0147] In this embodiment, the piezoelectric layer 405 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0148] It should be noted that forming the piezoelectric layer 405 on a plane can make the piezoelectric layer 405 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0149] In this embodiment, the portion of the electrode layer 403 that overlaps with the electrode layer 407 is located in the cavity 401 a ; and the portion of the electrode layer 407 that overlaps with the electrode layer 403 is located above the cavity 401 a .

[0150] In this embodiment, the material of the electrode layer 403 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 407 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0151] In this embodiment, the electrode layer 403 includes a negative electrode, and the electrode layer 407 includes a positive electrode. In another embodiment, the electrode layer 403 includes a positive electrode, and the electrode layer 407 includes a negative electrode.

[0152] Figure 4b 4 is a schematic diagram of the cross-section B of a bulk acoustic wave resonance device 400 according to an embodiment of the present invention.

[0153] like Figure 4b As shown, the resonant device 400 includes: the substrate 401, the upper surface side of the substrate 401 includes the cavity 401a; the etching shield layer 411 is located in the cavity 401a and covers the bottom and sidewalls of the cavity 401a; the electrode layer 403 includes four electrode strips 403b, and the cross section B of the electrode layer 403 is located in the cavity 401a; the piezoelectric layer 405 is located on the substrate 401 and the electrode layer 403; and the electrode layer 407 is located on the piezoelectric layer 405. Figure 4bIt can be seen that the resonance region 409 (ie, the overlapping region of the electrode layer 403 and the electrode layer 407 ) is suspended relative to the cavity 401 a and has no overlapping contact portion with the substrate 401 .

[0154] In this embodiment, the four electrode strips 403b include negative electrodes, and the electrode layer 407 includes positive electrodes. In another embodiment, the four electrode strips 403b include positive electrodes, and the electrode layer 407 includes negative electrodes.

[0155] In this embodiment, the spacing distance between two adjacent electrode strips 403b is consistent, including the first distance.

[0156] In this embodiment, the widths of the four electrode strips 403b are consistent, including the first width.

[0157] In this embodiment, the duty cycle of the four electrode strips 403b includes a first duty cycle corresponding to the first distance and the first width, and the value range thereof includes but is not limited to 0.1 to 1.

[0158] It should be noted that, when forming the electrode layer 403 , the operating frequency of the resonant device can be controlled by adjusting the first distance or the first width.

[0159] In other embodiments of the present invention, the number of electrodes included in the electrode layer 403 may be other even numbers, for example, 2, 6, 8, 10, 12, 14, 16, 18, 20, etc. In other embodiments of the present invention, the number of electrodes included in the electrode layer 403 may be an odd number, for example, 3, 5, 7, 9, 11, 13, 15, 17, 19, etc.

[0160] Figure 5a Schematic diagram of the cross-section A of a bulk acoustic wave resonance device 500 according to an embodiment of the present invention.

[0161] like Figure 5a As shown, the embodiment of the present invention provides a bulk acoustic wave resonator 500 including: a substrate 501; an intermediate layer 502, located on the substrate 501, the upper surface side of the intermediate layer 502 includes a cavity 502a; an electrode layer 503, the first end of the cross section A of the electrode layer 503 contacts the side wall of the cavity 502a, and the second end of the cross section A of the electrode layer 503 is located in the cavity 502a; a piezoelectric layer 505, located on the intermediate layer 502 and the electrode layer 503, the piezoelectric layer 505 is a flat layer, covering the cavity 502a; an electrode layer 507, located on the piezoelectric layer 505. Figure 5aIt can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 503 and the electrode layer 507) is suspended relative to the cavity 502a and has no overlapping contact portion with the intermediate layer 502, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 502a.

[0162] Therefore, the embodiment of the present invention can improve the difference between the acoustic impedance of the resonant region (not shown) and the non-resonant region, thereby improving the Q value of the resonant device. In addition, the acoustic impedance of the intermediate layer 502 can be small, thereby blocking the sound waves from leaking from the resonant region (not shown) into the substrate 501.

[0163] In this embodiment, the material of the substrate 501 includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0164] In this embodiment, the material of the intermediate layer 502 includes but is not limited to at least one of the following: polymer, insulating dielectric. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), photosensitive epoxy resin photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

[0165] In this embodiment, the thickness of the intermediate layer 502 includes but is not limited to: 0.1 micrometer to 10 micrometers.

[0166] In this embodiment, the piezoelectric layer 505 also covers the upper surface side. In this embodiment, the material of the piezoelectric layer 505 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0167] In this embodiment, the piezoelectric layer 505 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0168] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0169] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0170] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0171] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0172] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0173] In this embodiment, the piezoelectric layer 505 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0174] It should be noted that forming the piezoelectric layer 505 on a plane can make the piezoelectric layer 505 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0175] In this embodiment, the portion of the electrode layer 503 that overlaps with the electrode layer 507 is located in the cavity 502a; and the portion of the electrode layer 507 that overlaps with the electrode layer 503 is located above the cavity 502a.

[0176] In this embodiment, the material of the electrode layer 503 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 507 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0177] In this embodiment, the electrode layer 503 includes a negative electrode, and the electrode layer 507 includes a positive electrode. In another embodiment of the present invention, the electrode layer 503 includes a positive electrode, and the electrode layer 507 includes a negative electrode.

[0178] Figure 5b 1 is a schematic diagram of the cross-section B structure of a bulk acoustic wave resonance device 500 according to an embodiment of the present invention.

[0179] like Figure 5b As shown, the resonant device 500 includes: the substrate 501; the intermediate layer 502, which is located on the substrate 501, and the upper surface side of the intermediate layer 502 includes a cavity 502a; the electrode layer 503, whose cross section B is located in the cavity 502a; the piezoelectric layer 505, which is located on the intermediate layer 502 and the electrode layer 503; the electrode layer 507, which includes 5 electrode strips 507b, and the electrode layer 507 is located on the piezoelectric layer 505. Figure 5b It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 503 and the electrode layer 507) is suspended relative to the cavity 502a and has no overlapping contact portion with the intermediate layer 502. Thus, the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 502a.

[0180] In this embodiment, the electrode layer 503 includes a negative electrode, and the five electrode strips 507b include a positive electrode. In another embodiment, the electrode layer 503 includes a positive electrode, and the five electrode strips 507b include a negative electrode.

[0181] In this embodiment, the spacing distance between two adjacent electrode strips 507b is consistent, including the first distance.

[0182] In this embodiment, the widths of the five electrode strips 507b are consistent, including the first width.

[0183] In this embodiment, the duty cycle of the five electrode strips 507b includes a first duty cycle corresponding to the first distance and the first width, and the value range thereof includes but is not limited to 0.1 to 1.

[0184] It should be noted that, when forming the electrode layer 507 , the operating frequency of the resonant device can be controlled by adjusting the first distance or the first width.

[0185] In other embodiments, the number of electrodes included in the electrode layer 507 may be other odd numbers, for example, 3, 7, 9, 11, 13, 15, 17, 19, etc. In other embodiments, the number of electrodes included in the electrode layer 507 may be an even number, for example, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, etc.

[0186] Figure 6a Schematic diagram of the cross-section A of a bulk acoustic wave resonance device 600 according to an embodiment of the present invention.

[0187] like Figure 6a As shown, the embodiment of the present invention provides a bulk acoustic wave resonance device 600 including: a substrate 601; an intermediate layer 602, located on the substrate 601, the upper surface side of the cross section A of the intermediate layer 602 includes a cavity 602a and a groove 602b, wherein the groove 602b is located on one side of the cavity 602a in the horizontal direction and communicates with the cavity 602a, and the depth of the groove 602b is less than the depth of the cavity 602a; an electrode layer 603, the first end of the cross section A of the electrode layer 603 is located in the groove 602b, and the second end of the cross section A of the electrode layer 603 is located in the cavity 602a, wherein the depth of the groove 602b is equal to the thickness of the electrode 603; a piezoelectric layer 605, located on the intermediate layer 602 and the electrode layer 603, the piezoelectric layer 605 is a flat layer, covering the cavity 602a; an electrode layer 607, located on the piezoelectric layer 605. Figure 6a It can be seen that the resonance region (not shown, that is, the overlapped region of the electrode layer 603 and the electrode layer 607) is suspended relative to the cavity 602a and has no overlapped contact portion with the intermediate layer 602, so that the vertical projection of the resonance region (not shown) perpendicular to the upper surface is located within the cavity 602a.

[0188] The embodiment of the present invention can improve the difference between the acoustic impedance of the resonant region (not shown) and the non-resonant region, thereby improving the Q value of the resonant device. In addition, the acoustic impedance of the intermediate layer 602 can be small, thereby preventing sound waves from leaking from the resonant region (not shown) into the substrate 601.

[0189] In this embodiment, the material of the substrate 601 includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0190] In this embodiment, the material of the intermediate layer 602 includes but is not limited to at least one of the following: polymer, insulating dielectric. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), photosensitive epoxy resin photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

[0191] In this embodiment, the thickness of the intermediate layer 602 includes but is not limited to: 0.1 micrometer to 10 micrometers.

[0192] In this embodiment, the piezoelectric layer 605 also covers the upper surface side. In this embodiment, the material of the piezoelectric layer 605 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0193] In this embodiment, the piezoelectric layer 605 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0194] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0195] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0196] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0197] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0198] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0199] In this embodiment, the piezoelectric layer 605 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0200] It should be noted that forming the piezoelectric layer 605 on a plane can make the piezoelectric layer 605 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0201] In this embodiment, the portion of the electrode layer 603 that overlaps with the electrode layer 607 is located in the cavity 602a; and the portion of the electrode layer 607 that overlaps with the electrode layer 603 is located above the cavity 602a.

[0202] In this embodiment, the material of the electrode layer 603 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 607 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0203] In this embodiment, the electrode layer 603 includes a negative electrode, and the electrode layer 607 includes a positive electrode. In another embodiment of the present invention, the electrode layer 603 includes a positive electrode, and the electrode layer 607 includes a negative electrode.

[0204] Figure 6b Schematic diagram of the cross-section B of a bulk acoustic wave resonator device 600 according to an embodiment of the present invention.

[0205] like Figure 6b As shown, the resonant device 600 includes: the substrate 601; the intermediate layer 602, which is located on the substrate 601, and the upper surface side of the cross section B of the intermediate layer 602 includes a cavity 602a; the electrode layer 603, whose cross section B is located in the cavity 602a; the piezoelectric layer 605, which is located on the intermediate layer 602 and the electrode layer 603; the electrode layer 607, which includes 5 electrode strips 607b, and the electrode layer 607 is located on the piezoelectric layer 605. Figure 6b It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 603 and the electrode layer 607) is suspended relative to the cavity 602a and has no overlapping contact portion with the intermediate layer 602, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 602a.

[0206] In this embodiment, the electrode layer 603 includes a negative electrode, and the five electrode strips 607b include a positive electrode. In another embodiment, the electrode layer 603 includes a positive electrode, and the five electrode strips 607b include a negative electrode.

[0207] In this embodiment, the spacing distance between two adjacent electrode strips 607b is variable, including a first distance and a second distance, wherein the first distance is greater than the second distance.

[0208] In this embodiment, the widths of the five electrode strips 607b are variable, including a first width, a second width and a third width, wherein the first width is smaller than the second width, and the second width is smaller than the third width.

[0209] In this embodiment, the duty factors of the five electrode strips 607b include: a first duty factor, corresponding to the first distance and the first width; a second duty factor, corresponding to the first distance and the second width; a third duty factor, corresponding to the second distance and the second width; and a fourth duty factor, corresponding to the second distance and the third width; wherein the value ranges of the first duty factor, the second duty factor, the third duty factor and the fourth duty factor include but are not limited to 0.1 to 1.

[0210] It should be noted that, when forming the electrode layer 607 , the operating frequency of the resonant device can be controlled by adjusting the first distance or the second distance or the first width or the second width or the third width.

[0211] In other embodiments of the present invention, the number of electrodes included in the electrode layer 607 may be other odd numbers, for example, 3, 7, 9, 11, 13, 15, 17, 19, etc. In other embodiments of the present invention, the number of electrodes included in the electrode layer 607 may be an even number, for example, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, etc.

[0212] Figure 7a Schematic diagram of the cross-section A of a bulk acoustic wave resonator device 700 according to an embodiment of the present invention.

[0213] like Figure 7a As shown, the embodiment of the present invention provides a bulk acoustic wave resonator device 700 including: a substrate 701; an intermediate layer 702, located on the substrate 701, wherein the upper surface side of the cross section A of the intermediate layer 702 includes a cavity 702a and a groove 702b, wherein the groove 702b is located on one side of the cavity 702a in the horizontal direction and communicates with the cavity 702a, and the depth of the groove 702b is less than the depth of the cavity 702a; an etching shielding layer 711, wherein the cross section A covers the bottom and side walls of the cavity 702a, the bottom and side walls of the groove 702b , and the upper surface side of the intermediate layer 702; an electrode layer 703, wherein the first end of the cross-section A of the electrode layer 703 is located in the groove 702b, and the second end of the cross-section A of the electrode layer 703 is located in the cavity 702a, wherein the depth of the groove 702b is equal to the sum of the thickness of the etching shield layer 711 and the thickness of the electrode layer 703; a piezoelectric layer 705, located on the etching shield layer 711 and the electrode layer 703, the piezoelectric layer 705 is a flat layer, covering the cavity 702a; an electrode layer 707, located on the piezoelectric layer 705. Figure 7aIt can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 703 and the electrode layer 707) is suspended relative to the cavity 702a, and has no overlapping contact with the intermediate layer 702 and the etching shielding layer 711, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 702a.

[0214] The embodiment of the present invention can improve the difference between the acoustic impedance of the resonant region (not shown) and the non-resonant region, thereby improving the Q value of the resonant device. In addition, the acoustic impedance of the intermediate layer 702 can be small, thereby preventing sound waves from leaking from the resonant region (not shown) into the substrate 701.

[0215] In this embodiment, the material of the substrate 701 includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0216] In this embodiment, the material of the intermediate layer 702 includes but is not limited to at least one of the following: polymer, insulating dielectric. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), photosensitive epoxy resin photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

[0217] In this embodiment, the thickness of the intermediate layer 702 includes but is not limited to: 0.1 micrometer to 10 micrometers.

[0218] In this embodiment, the material of the etching shielding layer 711 includes but is not limited to at least one of the following: aluminum nitride, silicon carbide, diamond, silicon nitride, silicon dioxide, aluminum oxide, and titanium dioxide.

[0219] It should be noted that the etching shielding layer 711 can protect the intermediate layer 702 when the cavity 702a is formed by etching. In addition, the etching shielding layer 711 can protect the resonance device from being corroded by water and oxygen.

[0220] In this embodiment, the thickness of the etching shielding layer 711 includes but is not limited to: 0.1 micrometer to 3 micrometers.

[0221] In this embodiment, the piezoelectric layer 705 also covers the etching shielding layer 711. In this embodiment, the material of the piezoelectric layer 705 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0222] In this embodiment, the piezoelectric layer 705 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0223] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0224] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0225] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0226] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0227] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0228] In this embodiment, the piezoelectric layer 705 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0229] It should be noted that forming the piezoelectric layer 705 on a plane can make the piezoelectric layer 705 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0230] In this embodiment, the portion of the electrode layer 703 that overlaps with the electrode layer 707 is located in the cavity 702a; and the portion of the electrode layer 707 that overlaps with the electrode layer 703 is located above the cavity 702a.

[0231] In this embodiment, the material of the electrode layer 703 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 707 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0232] In this embodiment, the electrode layer 703 includes a positive electrode and a negative electrode, and the electrode layer 707 includes a positive electrode and a negative electrode.

[0233] Figure 7b 1 is a schematic diagram of the cross-section B structure of a bulk acoustic wave resonance device 700 according to an embodiment of the present invention.

[0234] like Figure 7b As shown, the resonant device 700 includes: the substrate 701; the intermediate layer 702, which is located on the substrate 701, and the upper surface side of the cross section B of the intermediate layer 702 includes the cavity 702a; the etching shield layer 711, whose cross section B covers the bottom and side walls of the cavity 702a and the upper surface side of the intermediate layer 702; the electrode layer 703, including two electrode strips 703b and two electrode strips 703c, and the cross section B of the electrode layer 703 is located in the cavity 702a; the piezoelectric layer 705, which is located on the etching shield layer 711 and the electrode layer 703; the electrode layer 707, which includes two electrode strips 707b and two electrode strips 707c, and the electrode layer 707 is located on the piezoelectric layer 705. Figure 7b It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 703 and the electrode layer 707) is suspended relative to the cavity 702a and has no overlapping contact portion with the intermediate layer 702, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 702a.

[0235] In this embodiment, the two electrode strips 703b include negative electrodes, the two electrode strips 703c include positive electrodes, the two electrode strips 707b include negative electrodes, and the two electrode strips 707c include positive electrodes. In another embodiment, the two electrode strips 703b include positive electrodes, the two electrode strips 703c include negative electrodes, the two electrode strips 707b include positive electrodes, and the two electrode strips 707c include negative electrodes.

[0236] In this embodiment, the distance between the electrode strip 703b and the electrode strip 703c is consistent, and the distance between the electrode strip 707b and the electrode strip 707c is consistent, including the first distance.

[0237] In this embodiment, the widths of the electrode strips 703b, 703c, 707b, 707c are consistent, including the first width.

[0238] In this embodiment, the duty cycle between the two electrode strips 703b includes a first duty cycle, corresponding to the first distance and the first width, and its value range includes but is not limited to 0.1 to 1. In this embodiment, the duty cycle between the two electrode strips 703c includes the first duty cycle. In this embodiment, the duty cycle between the two electrode strips 703b and the two electrode strips 703c includes the first duty cycle.

[0239] In this embodiment, correspondingly, the duty factor between the two electrode strips 707b includes the first duty factor. In this embodiment, correspondingly, the duty factor between the two electrode strips 707c includes the first duty factor. In this embodiment, correspondingly, the duty factor between the two electrode strips 707b and the two electrode strips 707c includes the first duty factor.

[0240] It should be noted that, when forming the electrode layers 703 and 707, the operating frequency of the resonant device can be controlled by adjusting the first distance or the first width.

[0241] In other embodiments, the number of electrode strips included in each of the electrode layers 703 and 707 may be other even numbers, for example, 2, 6, 8, 10, 12, 14, 16, 18, 20, etc. In other embodiments, the number of electrode strips included in each of the electrode layers 703 and 707 may be an odd number, for example, 3, 5, 7, 9, 11, 13, 15, 17, 19, etc.

[0242] In another embodiment, the electrode layer 703 includes 6 electrode strips, and the electrode layer 707 also includes 6 electrode strips, wherein the polarities of the 6 electrode strips included in the electrode layer 703 are negative, negative, positive, positive, positive, negative, negative from left to right in the horizontal direction, and the polarities of the 6 electrode strips included in the electrode layer 707 are positive, positive, negative, negative, negative, positive, positive from left to right in the horizontal direction. In another embodiment, the polarities of the 6 electrode strips included in the electrode layer 703 are negative, negative, negative, positive, positive, positive from left to right in the horizontal direction, and the polarities of the 6 electrode strips included in the electrode layer 707 are positive, positive, positive, positive, negative, negative, negative from left to right in the horizontal direction.

[0243] In another embodiment, the electrode layer 703 includes 5 electrode strips, and the electrode layer 707 also includes 5 electrode strips, wherein the polarities of the 5 electrode strips included in the electrode layer 703 are negative, negative, positive, negative, negative from left to right in the horizontal direction, and the polarities of the 5 electrode strips included in the electrode layer 707 are positive, positive, negative, positive, positive from left to right in the horizontal direction. In another embodiment, the polarities of the 5 electrode strips included in the electrode layer 703 are negative, negative, negative, positive, positive from left to right in the horizontal direction, and the polarities of the 5 electrode strips included in the electrode layer 707 are positive, positive, positive, positive, negative, negative from left to right in the horizontal direction.

[0244] Figure 8a Schematic diagram of the cross-section A of a bulk acoustic wave resonance device 800 according to an embodiment of the present invention.

[0245] like Figure 8a As shown, the embodiment of the present invention provides a bulk acoustic wave resonator 800 including: a support layer 802, wherein the upper surface side of the support layer 802 includes a cavity 802a; an electrode layer 803, wherein the first end of the cross section A of the electrode layer 803 contacts the side wall of the cavity 802a, and the second end of the cross section A of the electrode layer 803 is located in the cavity 802a; a piezoelectric layer 805, which is located on the support layer 802 and the electrode layer 803, and the piezoelectric layer 805 is a flat layer, covering the cavity 802a; and an electrode layer 807, which is located on the piezoelectric layer 805. Figure 8a It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 803 and the electrode layer 807) is suspended relative to the cavity 802a and has no overlapping contact portion with the support layer 802, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 802a.

[0246] The embodiment of the present invention can improve the difference in acoustic impedance between the resonant region (not shown) and the non-resonant region, thereby improving the Q value of the resonant device. In addition, the resonant device 800 provided by the embodiment of the present invention does not include a substrate, thereby eliminating electrical losses caused by the substrate.

[0247] In this embodiment, the material of the support layer 802 includes but is not limited to at least one of the following: polymer, insulating dielectric. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), photosensitive epoxy resin photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

[0248] In this embodiment, the thickness of the support layer 802 includes but is not limited to: 20 microns to 100 microns.

[0249] In this embodiment, the piezoelectric layer 805 also covers the upper surface side. In this embodiment, the material of the piezoelectric layer 805 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0250] In this embodiment, the piezoelectric layer 805 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0251] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0252] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0253] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0254] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0255] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0256] In this embodiment, the piezoelectric layer 805 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0257] It should be noted that forming the piezoelectric layer 805 on a plane can make the piezoelectric layer 805 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0258] In this embodiment, the portion of the electrode layer 803 that overlaps with the electrode layer 807 is located in the cavity 802a; and the portion of the electrode layer 807 that overlaps with the electrode layer 803 is located above the cavity 802a.

[0259] In this embodiment, the material of the electrode layer 803 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 807 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0260] In this embodiment, the electrode layer 803 includes a negative electrode, and the electrode layer 807 includes a positive electrode. In another embodiment of the present invention, the electrode layer 803 includes a positive electrode, and the electrode layer 807 includes a negative electrode.

[0261] Figure 8b 1 is a schematic diagram of the cross-section B structure of a bulk acoustic wave resonance device 800 according to an embodiment of the present invention.

[0262] like Figure 8b As shown, the resonant device 800 includes: the support layer 802, the upper surface side of the support layer 802 includes the cavity 802a; the electrode layer 803 includes four electrode strips 803b, and the cross section B of the electrode layer 803 is located in the cavity 802a; the piezoelectric layer 805 is located on the support layer 802 and the electrode layer 803; the electrode layer 807 includes four electrode strips 807b, and the electrode layer 807 is located on the piezoelectric layer 805. Figure 8b It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 803 and the electrode layer 807) is suspended relative to the cavity 802a and has no overlapping contact portion with the support layer 802, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 802a.

[0263] Electricity Loss In this embodiment, the four electrode strips 803b include negative electrodes, and the four electrode strips 807b include positive electrodes. In another embodiment, the four electrode strips 803b include positive electrodes, and the four electrode strips 807b include negative electrodes.

[0264] In this embodiment, the distances between the electrode strips 803b are consistent, and the distances between the electrode strips 807b are consistent, including the first distance.

[0265] In this embodiment, the widths of the electrode strips 803b and 807b are consistent, including a first width.

[0266] In this embodiment, the duty cycle of the four electrode strips 803b includes a first duty cycle corresponding to the first distance and the first width, and the value range thereof includes but is not limited to 0.1 to 1.

[0267] In this embodiment, correspondingly, the duty cycle of the four electrode strips 807b includes the first duty cycle.

[0268] It should be noted that, when forming the electrode layers 803 and 807, the operating frequency of the resonant device can be controlled by adjusting the first distance or the first width.

[0269] In other embodiments of the present invention, the number of electrode strips included in each of the electrode layers 803 and 807 may be other even numbers, for example, 2, 6, 8, 10, 12, 14, 16, 18, 20, etc. In other embodiments of the present invention, the number of electrode strips included in each of the electrode layers 803 and 807 may be an odd number, for example, 3, 5, 7, 9, 11, 13, 15, 17, 19, etc.

[0270] Figure 9a 1 is a schematic structural diagram of a cross-section A of a bulk acoustic wave resonance device 900 according to an embodiment of the present invention.

[0271] like Figure 9a As shown, an embodiment of the present invention provides a bulk acoustic wave resonance device 900 including: a support layer 902, wherein the upper surface side of the cross-section A of the support layer 902 includes a cavity 902a and a groove 902b, wherein the groove 902b is located on one side of the cavity 902a in the horizontal direction and communicates with the cavity 902a, and the depth of the groove 902b is less than the depth of the cavity 902a; an electrode layer 903, wherein the first end of the cross-section A of the electrode layer 903 is located in the groove 902b, and the second end of the cross-section A of the electrode layer 903 is located in the cavity 902a, wherein the depth of the groove 902b is equal to the thickness of the electrode layer 903; a piezoelectric layer 905, located on the support layer 902 and the electrode layer 903, the piezoelectric layer 905 is a flat layer, covering the cavity 902a; and an electrode layer 907, located on the piezoelectric layer 905. Figure 9a It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 903 and the electrode layer 907) is suspended relative to the cavity 902a and has no overlapping contact portion with the support layer 902, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 902a.

[0272] The embodiment of the present invention can improve the difference in acoustic impedance between the resonant region (not shown) and the non-resonant region, thereby improving the Q value of the resonant device. In addition, the resonant device 900 provided by the embodiment of the present invention does not include a substrate, thereby eliminating electrical losses caused by the substrate.

[0273] In this embodiment, the material of the support layer 902 includes but is not limited to at least one of the following: polymer, insulating dielectric. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), photosensitive epoxy resin photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

[0274] In this embodiment, the thickness of the support layer 902 includes but is not limited to: 20 micrometers to 100 micrometers.

[0275] In this embodiment, the piezoelectric layer 905 also covers the upper surface side. In this embodiment, the material of the piezoelectric layer 905 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0276] In this embodiment, the piezoelectric layer 905 includes a plurality of crystals, the plurality of crystals including a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0277] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0278] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0279] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0280] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0281] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0282] In this embodiment, the piezoelectric layer 905 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0283] It should be noted that forming the piezoelectric layer 905 on a plane can make the piezoelectric layer 905 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0284] In this embodiment, the portion of the electrode layer 903 that overlaps with the electrode layer 907 is located in the cavity 902a; and the portion of the electrode layer 907 that overlaps with the electrode layer 903 is located above the cavity 902a.

[0285] In this embodiment, the material of the electrode layer 903 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 907 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0286] In this embodiment, the electrode layer 903 includes a negative electrode, and the electrode layer 907 includes a positive electrode. In another embodiment, the electrode layer 903 includes a positive electrode, and the electrode layer 907 includes a negative electrode.

[0287] Figure 9b 1 is a schematic diagram of the cross-section B structure of a bulk acoustic wave resonance device 900 according to an embodiment of the present invention.

[0288] like Figure 9b As shown, the resonant device 900 includes: the support layer 902, the upper surface side of the cross section B of the support layer 902 includes the cavity 902a; the electrode layer 903 includes four electrode strips 903b, and the cross section B of the electrode layer 903 is located in the cavity 902a; the piezoelectric layer 905 is located on the support layer 902 and the electrode layer 903; the electrode layer 907 includes four electrode strips 907b, and the electrode layer 907 is located on the piezoelectric layer 905. Figure 9bIt can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 903 and the electrode layer 907) is suspended relative to the cavity 902a and has no overlapping contact portion with the support layer 902, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 902a.

[0289] Electricity Loss In this embodiment, the four electrode strips 903b include negative electrodes, and the four electrode strips 907b include positive electrodes. In another embodiment, the four electrode strips 903b include positive electrodes, and the four electrode strips 907b include negative electrodes.

[0290] In this embodiment, the spacing distance between two adjacent electrode strips 903b is variable, including: a first distance and a second distance, wherein the first distance is smaller than the second distance.

[0291] In this embodiment, correspondingly, the spacing distance between two adjacent electrode strips 907b is variable, including: a third distance and a fourth distance, wherein the third distance is smaller than the fourth distance, the first distance is equal to or close to the third distance, and the second distance is equal to or close to the fourth distance.

[0292] In this embodiment, the widths of the four electrode strips 903b are variable, including: a first width and a second width, wherein the first width is greater than the second width.

[0293] In this embodiment, correspondingly, the widths of the four electrode strips 907b are variable, including: a third width and a fourth width, wherein the third width is greater than the fourth width, the first width is equal to or similar to the third width, and the second width is equal to or similar to the fourth width.

[0294] In this embodiment, the duty factors of the four electrode strips 903b include: a first duty factor, corresponding to the first width and the first distance; a second duty factor, corresponding to the second width and the first distance; a third duty factor, corresponding to the second width and the second distance; and a fourth duty factor, corresponding to the first width and the second distance, wherein the value ranges of the first duty factor, the second duty factor, the third duty factor and the fourth duty factor include but are not limited to 0.1 to 1.

[0295] In this embodiment, correspondingly, the duty cycles of the four electrode strips 907b include: the first duty cycle, the second duty cycle, the third duty cycle and the fourth duty cycle.

[0296] It should be noted that, when forming the electrode layers 903 and 907, the operating frequency of the resonant device can be controlled by adjusting the first distance or the second distance or the first width or the second width.

[0297] In other embodiments, the number of electrode strips included in each of the electrode layers 903 and 907 may be other even numbers, for example, 2, 6, 8, 10, 12, 14, 16, 18, 20, etc. In other embodiments, the number of electrode strips included in each of the electrode layers 903 and 907 may be an odd number, for example, 3, 5, 7, 9, 11, 13, 15, 17, 19, etc.

[0298] Fig.10a 1 is a schematic diagram of the cross-section A of a bulk acoustic wave resonance device 1000 according to an embodiment of the present invention.

[0299] like Fig.10a As shown, the embodiment of the present invention provides a bulk acoustic wave resonance device 1000 including: a support layer 1002, wherein the upper surface side of the cross section A of the support layer 1002 includes a cavity 1002a and a groove 1002b, wherein the groove 1002b is located on one side of the cavity 1002a in the horizontal direction and communicates with the cavity 1002a, and the depth of the groove 1002b is less than the depth of the cavity 1002a; an etching shielding layer 1011, wherein the cross section A covers the bottom and side walls of the cavity 1002a, the bottom and side walls of the groove 1002b, and the support layer 1002; 02; electrode layer 1003, the first end of the cross section A of the electrode layer 1003 is located in the groove 1002b, and the second end of the cross section A of the electrode layer 1003 is located in the cavity 1002a, wherein the depth of the groove 1002b is equal to the sum of the thickness of the etching shield layer 1011 and the thickness of the electrode layer 1003; piezoelectric layer 1005, located on the etching shield layer 1011 and the electrode layer 1003, the piezoelectric layer 1005 is a flat layer, covering the cavity 1002a; electrode layer 1007, located on the piezoelectric layer 1005. Fig.10a It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 1003 and the electrode layer 1007) is suspended relative to the cavity 1002a, and has no overlapping contact with the support layer 1002 and the corresponding etching shielding layer 1011, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 1002a.

[0300] The embodiment of the present invention can improve the difference in acoustic impedance between the resonant region (not shown) and the non-resonant region, thereby improving the Q value of the resonant device. In addition, the resonant device 1000 provided by the embodiment of the present invention does not include a substrate, thereby eliminating electrical losses caused by the substrate.

[0301] In this embodiment, the material of the support layer 1002 includes but is not limited to at least one of the following: polymer, insulating dielectric. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), photosensitive epoxy resin photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

[0302] In this embodiment, the thickness of the support layer 1002 includes but is not limited to: 20 microns to 100 microns.

[0303] In this embodiment, the material of the etching shielding layer 1011 includes but is not limited to at least one of the following: aluminum nitride, silicon carbide, diamond, silicon nitride, silicon dioxide, aluminum oxide, and titanium dioxide.

[0304] In this embodiment, the thickness of the etching shielding layer 1011 includes but is not limited to: 2 microns to 6 microns.

[0305] It should be noted that the etching shielding layer 1011 can protect the supporting layer 1002 when the cavity 1002a is formed by etching. In addition, the etching shielding layer 1011 can protect the resonance device from being corroded by water and oxygen.

[0306] In this embodiment, the piezoelectric layer 305 also covers the etching shielding layer 1011. In this embodiment, the material of the piezoelectric layer 1005 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0307] In this embodiment, the piezoelectric layer 1005 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0308] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0309] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0310] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0311] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0312] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0313] In this embodiment, the piezoelectric layer 1005 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0314] It should be noted that forming the piezoelectric layer 1005 on a plane can make the piezoelectric layer 1005 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0315] In this embodiment, the portion of the electrode layer 1003 that overlaps with the electrode layer 1007 is located in the cavity 1002a; and the portion of the electrode layer 1007 that overlaps with the electrode layer 1003 is located above the cavity 1002a.

[0316] In this embodiment, the material of the electrode layer 1003 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 1007 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0317] In this embodiment, the electrode layer 1003 includes a positive electrode and a negative electrode, and the electrode layer 1007 includes a positive electrode and a negative electrode.

[0318] Fig.10b 1 is a schematic diagram of the cross-section B structure of a bulk acoustic wave resonance device 1000 according to an embodiment of the present invention.

[0319] like Fig.10b As shown, the resonant device 1000 includes: the support layer 1002, the upper surface side of the cross section B of the support layer 1002 includes the cavity 1002a; the etching shield layer 1011, the cross section B of which covers the bottom and sidewalls of the cavity 1002a and the upper surface side of the support layer 1002; the electrode layer 1003, including two electrode strips 1003b and two electrode strips 1003c, the cross section B of the electrode layer 1003 is located in the cavity 1002a; the piezoelectric layer 1005 is located on the etching shield layer 1011 and the electrode layer 1003; the electrode layer 1007, including two electrode strips 1007b and two electrode strips 1007c, the electrode layer 1007 is located on the piezoelectric layer 1005. Fig.10b It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 1003 and the electrode layer 1007) is suspended relative to the cavity 1002a and has no overlapping contact portion with the support layer 1002, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 1002a.

[0320] Electric loss In this embodiment, the two electrode strips 1003b include negative electrodes, the two electrode strips 1003c include positive electrodes, the two electrode strips 1007b include negative electrodes, and the two electrode strips 1007c include positive electrodes. In another embodiment, the two electrode strips 1003b include positive electrodes, the two electrode strips 1003c include negative electrodes, the two electrode strips 1007b include positive electrodes, and the two electrode strips 1007c include negative electrodes.

[0321] In this embodiment, the spacing distances between adjacent electrode strips 1003b and 1003c are consistent, including the first distance.

[0322] In this embodiment, correspondingly, the spacing distances between adjacent electrode strips 1007b and 1007c are consistent, including a second distance, and the first distance is equal to or close to the second distance.

[0323] In this embodiment, the width of the two electrode strips 1003b is consistent with the width of the two electrode strips 1003c, including the first width.

[0324] In this embodiment, correspondingly, the width of the two electrode strips 1007b is consistent with the width of the two electrode strips 1007c, including a second width, and the first width is equal to or similar to the second width.

[0325] In this embodiment, the duty cycle of the two electrode strips 1003b and the two electrode strips 1003c includes a first duty cycle corresponding to the first distance and the first width, and the value range thereof includes but is not limited to 0.1 to 1.

[0326] In this embodiment, correspondingly, the duty cycle of the two electrode strips 1007b and the two electrode strips 1007c include the first duty cycle.

[0327] It should be noted that, when forming the electrode layers 1003 and 1007 , the operating frequency of the resonant device can be controlled by adjusting the first distance or the first width.

[0328] In other embodiments, the number of electrodes included in the electrode layers 1003 and 1007 may be other even numbers, for example, 2, 6, 8, 10, 12, 14, 16, 18, 20, etc. In other embodiments, the number of electrodes included in the electrode layers 1003 and 1007 may be odd numbers, for example, 3, 5, 7, 9, 11, 13, 15, 17, 19, etc.

[0329] Fig.11a 1 is a schematic diagram of the cross-section A of a bulk acoustic wave resonator device 1100 according to an embodiment of the present invention.

[0330] like Fig.11a As shown, the embodiment of the present invention provides a bulk acoustic wave resonance device 1100 including: a substrate 1101; a thin film 1104, located on the substrate 1101; an intermediate layer 1102, located on the thin film 1104, the upper surface side of the intermediate layer 1102 includes a cavity 1102a; an electrode layer 1103, the first end of the cross section A of the electrode layer 1103 contacts the side wall of the cavity 1102a, and the second end of the cross section A of the electrode layer 1103 is located in the cavity 1102a; a piezoelectric layer 1105, located on the intermediate layer 1102 and the electrode layer 1103, the piezoelectric layer 1105 is a flat layer, covering the cavity 1102a; an electrode layer 1107, located on the piezoelectric layer 1105. Fig.11a It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 1103 and the electrode layer 1107) is suspended relative to the cavity 1102a and has no overlapping contact portion with the intermediate layer 1102, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 1102a.

[0331] The embodiment of the present invention can improve the difference between the acoustic impedance of the resonant region (not shown) and the non-resonant region, thereby improving the Q value of the resonant device. In addition, the acoustic impedance of the intermediate layer 1102 can be small, thereby blocking the sound waves from leaking from the resonant region (not shown) into the substrate 1101. In addition, the film 1104 helps to prevent the formation of a free electron layer on the surface of the substrate 1101, so as to reduce the electrical loss caused by the substrate 1101.

[0332] In this embodiment, the material of the substrate 1101 includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0333] In this embodiment, the film 1104 includes but is not limited to a polycrystalline film. In this embodiment, the material of the polycrystalline film includes but is not limited to at least one of the following: polycrystalline silicon, polycrystalline silicon nitride, and polycrystalline silicon carbide.

[0334] In this embodiment, the material of the intermediate layer 1102 includes but is not limited to at least one of the following: polymer, insulating dielectric. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), photosensitive epoxy resin photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

[0335] In this embodiment, the thickness of the intermediate layer 1102 includes but is not limited to: 0.1 micrometer to 10 micrometers.

[0336] In this embodiment, the piezoelectric layer 1105 also covers the upper surface side. In this embodiment, the material of the piezoelectric layer 1105 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0337] In this embodiment, the piezoelectric layer 1105 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14 As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0338] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0339] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0340] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0341] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0342] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0343] In this embodiment, the piezoelectric layer 1105 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function value is equal to half of the peak value in a peak of the function.

[0344] It should be noted that forming the piezoelectric layer 1105 on a plane can make the piezoelectric layer 1105 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0345] In this embodiment, the portion of the electrode layer 1103 that overlaps with the electrode layer 1107 is located in the cavity 1102a; and the portion of the electrode layer 1107 that overlaps with the electrode layer 1103 is located above the cavity 1102a.

[0346] In this embodiment, the material of the electrode layer 1103 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 1107 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0347] In this embodiment, the electrode layer 1103 includes a positive electrode and a negative electrode, and the electrode layer 1107 includes a positive electrode and a negative electrode.

[0348] Fig.11b 1 is a schematic diagram of the cross-section B structure of a bulk acoustic wave resonance device 1100 according to an embodiment of the present invention.

[0349] like Fig.11b As shown, the resonant device 1100 includes: the substrate 1101; the film 1104, located on the substrate 1101; the intermediate layer 1102, located on the film 1104, the upper surface side of the intermediate layer 1102 includes the cavity 1102a; the electrode layer 1103, including two electrode strips 1103b and two electrode strips 1103c, the section B of the electrode layer 1103 is located in the cavity 1102a; the piezoelectric layer 1105, located on the intermediate layer 1102 and the electrode layer 1103; the electrode layer 1107, including two electrode strips 1107b and two electrode strips 1107c, the electrode layer 1107 is located on the piezoelectric layer 1105. Fig.11b It can be seen that the resonance zone (not shown, i.e., the overlapping area of ​​the electrode layer 1103 and the electrode layer 1107) is suspended relative to the cavity 1102a and has no overlapping contact portion with the intermediate layer 1102, so that the vertical projection of the resonance zone (not shown) perpendicular to the upper surface is located within the cavity 1102a.

[0350] In this embodiment, the two electrode strips 1103b include negative electrodes, the two electrode strips 1103c include positive electrodes, the two electrode strips 1107b include negative electrodes, and the two electrode strips 1107c include positive electrodes. In another embodiment, the two electrode strips 1103b include positive electrodes, the two electrode strips 1103c include negative electrodes, the two electrode strips 1107b include positive electrodes, and the two electrode strips 1107c include negative electrodes.

[0351] In this embodiment, the spacing distances between adjacent electrode strips 1103b and 1103c are consistent, including the first distance.

[0352] In this embodiment, correspondingly, the spacing distances between adjacent electrode strips 1107b and 1107c are consistent, including a second distance, and the first distance is equal to or close to the second distance.

[0353] In this embodiment, the widths of the two electrode strips 1103b and the two electrode strips 1103c are consistent, including the first width.

[0354] In this embodiment, the widths of the two electrode strips 1107b and the two electrode strips 1107c are consistent, including a second width, and the first width is equal to or similar to the second width.

[0355] In this embodiment, the duty cycle of the two electrode strips 1103b and the two electrode strips 1103c includes a first duty cycle corresponding to the first distance and the first width, and the value range thereof includes but is not limited to 0.1 to 1.

[0356] In this embodiment, correspondingly, the duty cycle of the two electrode strips 1107b and the two electrode strips 1107c include the first duty cycle.

[0357] It should be noted that when forming the electrode layers 1103 and 1107 , the operating frequency of the resonant device can be controlled by adjusting the first distance or the first width.

[0358] In other embodiments, the number of electrode strips included in each of the electrode layers 1103 and 1107 may be other even numbers, for example, 2, 6, 8, 10, 12, 14, 16, 18, 20, etc. In other embodiments, the number of electrode strips included in each of the electrode layers 1103 and 1107 may be an odd number, for example, 3, 5, 7, 9, 11, 13, 15, 17, 19, etc.

[0359] Fig.12a 1 is a schematic diagram of the cross-section A of a bulk acoustic wave resonance device 1200 according to an embodiment of the present invention.

[0360] like Fig.12a As shown, the embodiment of the present invention provides a bulk acoustic wave resonance device 1200 including: a substrate 1201; a thin film 1204, located on the substrate 1201; an intermediate layer 1202, located on the thin film 1204, the upper surface side of the cross section A of the intermediate layer 1202 includes a cavity 1202a and a groove 1202b, wherein the groove 1202b is located on one side of the cavity 1202a in the horizontal direction and communicates with the cavity 1202a, and the depth of the groove 1202b is less than that of the cavity 1202a The electrode layer 1203 has a first end in the section A of the electrode layer 1203 located in the groove 1202b, and a second end in the section A of the electrode layer 1203 located in the cavity 1202a, wherein the depth of the groove 1202b is equal to the thickness of the electrode layer 1203; a piezoelectric layer 1205 located on the intermediate layer 1202 and the electrode layer 1203, the piezoelectric layer 1205 being a flat layer and covering the cavity 1202a; and an electrode layer 1207 located on the piezoelectric layer 1205. Fig.12a It can be seen that the resonance region (not shown, that is, the overlapped region of the electrode layer 1203 and the electrode layer 1207) is suspended relative to the cavity 1202a and has no overlapped contact portion with the intermediate layer 1202, so that the vertical projection of the resonance region (not shown) perpendicular to the upper surface is located within the cavity 1202a.

[0361] The embodiment of the present invention can improve the difference between the acoustic impedance of the resonant region (not shown) and the non-resonant region, thereby improving the Q value of the resonant device. In addition, the acoustic impedance of the intermediate layer 1202 can be small, thereby blocking the sound waves from leaking from the resonant region (not shown) into the substrate 1201. In addition, the film 1204 helps to prevent the formation of a free electron layer on the surface of the substrate 1201, so as to reduce the electrical loss caused by the substrate 1201.

[0362] In this embodiment, the material of the substrate 1201 includes but is not limited to at least one of the following: silicon, silicon carbide, and glass.

[0363] In this embodiment, the film 1204 includes but is not limited to a polycrystalline film. In this embodiment, the material of the polycrystalline film includes but is not limited to at least one of the following: polycrystalline silicon, polycrystalline silicon nitride, and polycrystalline silicon carbide.

[0364] In this embodiment, the material of the intermediate layer 1202 includes but is not limited to at least one of the following: polymer, insulating dielectric. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (i.e., BCB), photosensitive epoxy resin photoresist (e.g., SU-8), polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, titanium oxide.

[0365] In this embodiment, the thickness of the intermediate layer 1202 includes but is not limited to: 0.1 micrometer to 10 micrometers.

[0366] In this embodiment, the piezoelectric layer 1205 also covers the upper surface side. In this embodiment, the material of the piezoelectric layer 1205 includes but is not limited to at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate.

[0367] In this embodiment, the piezoelectric layer 1205 includes a plurality of crystals, and the plurality of crystals include a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals. A person skilled in the art knows that the crystal orientation, crystal plane, etc. of a crystal can be represented based on a coordinate system. Fig.13 As shown in FIG. 1 , for a hexagonal crystal, such as aluminum nitride crystal, an ac stereo coordinate system (including an a-axis and a c-axis) is used to represent it. Fig.14As shown, for crystals of (i) orthorhombic system (a≠b≠c), (ii) tetragonal system (a=b≠c), (iii) cubic system (a=b=c), etc., an xyz three-dimensional coordinate system (including x-axis, y-axis and z-axis) is used for representation. In addition to the above two examples, crystals can also be represented based on other coordinate systems known to those skilled in the art, so the present invention is not limited to the above two examples.

[0368] In this embodiment, the first crystal can be represented based on a first three-dimensional coordinate system, and the second crystal can be represented based on a second three-dimensional coordinate system, wherein the first three-dimensional coordinate system at least includes a first coordinate axis along a first direction and a third coordinate axis along a third direction, and the second three-dimensional coordinate system at least includes a second coordinate axis along a second direction and a fourth coordinate axis along a fourth direction, wherein the first coordinate axis corresponds to the height of the first crystal, and the second coordinate axis corresponds to the height of the second crystal.

[0369] In this embodiment, the first direction and the second direction are the same or opposite. It should be noted that the first direction and the second direction are the same means that the angle between the vector along the first direction and the vector along the second direction ranges from 0 degrees to 5 degrees; the first direction and the second direction are opposite means that the angle between the vector along the first direction and the vector along the second direction ranges from 175 degrees to 180 degrees.

[0370] In another embodiment, the first three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the first coordinate axis is the first c-axis, and the third coordinate axis is the first a-axis; the second three-dimensional coordinate system is an ac three-dimensional coordinate system, wherein the second coordinate axis is the second c-axis, and the fourth coordinate axis is the second a-axis, wherein the first c-axis and the second c-axis point in the same or opposite directions.

[0371] In another embodiment, the first three-dimensional coordinate system further includes a fifth coordinate axis along a fifth direction, and the second three-dimensional coordinate system further includes a sixth coordinate axis along a sixth direction. In another embodiment, the first direction is the same as or opposite to the second direction, and the third direction is the same as or opposite to the fourth direction. It should be noted that the third direction is the same as the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 0 degrees to 5 degrees; the third direction is opposite to the fourth direction, which means that the angle between the vector along the third direction and the vector along the fourth direction ranges from 175 degrees to 180 degrees.

[0372] In another embodiment, the first three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the first coordinate axis is the first z-axis, the third coordinate axis is the first y-axis, and the fifth coordinate axis is the first x-axis; the second three-dimensional coordinate system is an xyz three-dimensional coordinate system, wherein the second coordinate axis is the second z-axis, the fourth coordinate axis is the second y-axis, and the sixth coordinate axis is the second x-axis. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in the same direction. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in the same direction, and the first y-axis and the second y-axis point in opposite directions. In another embodiment, the first z-axis and the second z-axis point in opposite directions, and the first y-axis and the second y-axis point in the same direction.

[0373] In this embodiment, the piezoelectric layer 1205 includes a plurality of crystals, and the half-peak width of the rocking curve of the crystal composed of the plurality of crystals is less than 2.5 degrees. It should be noted that the rocking curve describes the angular divergence of a certain crystal plane (the crystal plane determined by the diffraction angle) in the sample, and is represented by a plane coordinate system, wherein the horizontal axis is the angle between the crystal plane and the sample plane, and the vertical axis represents the diffraction intensity of the crystal plane at a certain angle. The rocking curve is used to represent the quality of the crystal, and the smaller the half-peak width angle, the better the crystal quality. In addition, the full width at half maximum (FWHM) refers to the distance between the two points where the function values ​​before and after a peak are equal to half of the peak value.

[0374] It should be noted that forming the piezoelectric layer 1205 on a plane can make the piezoelectric layer 1205 not include crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonant device and the Q value of the resonant device.

[0375] In this embodiment, the portion of the electrode layer 1203 that overlaps with the electrode layer 1207 is located in the cavity 1202a; and the portion of the electrode layer 1207 that overlaps with the electrode layer 1203 is located above the cavity 1202a.

[0376] In this embodiment, the material of the electrode layer 1203 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the electrode layer 1207 includes but is not limited to at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

[0377] In this embodiment, the electrode layer 1203 includes a positive electrode and a negative electrode, and the electrode layer 1207 includes a positive electrode and a negative electrode.

[0378] Figure 12b 1 is a schematic diagram of the cross-section B structure of a bulk acoustic wave resonance device 1200 according to an embodiment of the present invention.

[0379] like Figure 12b As shown, the resonant device 1200 includes: the substrate 1201; the film 1204, which is located on the substrate 1201; the intermediate layer 1202, which is located on the film 1204, and the upper surface side of the cross section B of the intermediate layer 1202 includes the cavity 1202a; the electrode layer 1203, which includes two electrode strips 1203b and two electrode strips 1203c, and the cross section B of the electrode layer 1203 is located in the cavity 1202a; the piezoelectric layer 1205, which is located on the intermediate layer 1202 and the electrode layer 1203; the electrode layer 1207, which includes two electrode strips 1207b and two electrode strips 1207c, and the electrode layer 1207 is located on the piezoelectric layer 1205. Figure 12b It can be seen that the resonance region (not shown, that is, the overlapped region of the electrode layer 1203 and the electrode layer 1207) is suspended relative to the cavity 1202a and has no overlapped contact portion with the intermediate layer 1202, so that the vertical projection of the resonance region (not shown) perpendicular to the upper surface is located within the cavity 1202a.

[0380] In this embodiment, the two electrode strips 1203b include negative electrodes, the two electrode strips 1203c include positive electrodes, the two electrode strips 1207b include negative electrodes, and the two electrode strips 1207c include positive electrodes. In another embodiment, the two electrode strips 1203b include positive electrodes, the two electrode strips 1203c include negative electrodes, the two electrode strips 1207b include positive electrodes, and the two electrode strips 1207c include negative electrodes.

[0381] In this embodiment, the spacing distance between adjacent electrode strips 1203b and 1203c is variable, including a first distance and a second distance, wherein the first distance is smaller than the second distance.

[0382] In this embodiment, correspondingly, the spacing distance between adjacent electrode strips 1207b and 1207c is variable, including a third distance and a fourth distance, wherein the third distance is smaller than the fourth distance, the first distance is equal to or close to the third distance, and the second distance is equal to or close to the fourth distance.

[0383] In this embodiment, the widths of the two electrode strips 1203b and the two electrode strips 1203c are variable, including a first width and a second width, wherein the first width is greater than the second width.

[0384] In this embodiment, correspondingly, the widths of the two electrode strips 1207b and the two electrode strips 1207c are variable, including a third width and a fourth width, wherein the third width is greater than the fourth width, the first width is equal to or similar to the third width, and the second width is equal to or similar to the fourth width.

[0385] In this embodiment, the duty factors of the two electrode strips 1203b and the two electrode strips 1203c include: a first duty factor, corresponding to the first distance and the first width; a second duty factor, corresponding to the first distance and the second width; and a third duty factor, corresponding to the second distance and the second width; wherein the value ranges of the first duty factor, the second duty factor, and the third duty factor include but are not limited to 0.1 to 1.

[0386] In this embodiment, correspondingly, the duty cycles of the two electrode strips 1207b and the two electrode strips 1207c include: the first duty cycle, the second duty cycle and the third duty cycle.

[0387] It should be noted that, when forming the electrode layers 1203 and 1207, the operating frequency of the resonant device can be controlled by adjusting the first distance or the second distance or the first width or the second width.

[0388] In other embodiments, the number of electrode strips included in each of the electrode layers 1203 and 1207 may be other even numbers, for example, 2, 6, 8, 10, 12, 14, 16, 18, 20, etc. In other embodiments, the number of electrode strips included in each of the electrode layers 1203 and 1207 may be an odd number, for example, 3, 5, 7, 9, 11, 13, 15, 17, 19, etc.

[0389] An embodiment of the present invention further provides a bulk acoustic wave filter device, including but not limited to: a bulk acoustic wave resonance device provided by at least one of the above embodiments.

[0390] In summary, the present invention adjusts the positions of the two electrode layers so that there is no overlapping contact between the resonance zone and the intermediate layer or the support layer or the first substrate, and the resonance zone is suspended relative to the cavity of the intermediate layer or the support layer or the first substrate, which can enhance the difference in acoustic impedance between the resonance zone and the non-resonance zone and improve the Q value of the resonance device. In addition, forming a piezoelectric layer on a plane can prevent the piezoelectric layer from including crystals with obvious turning, thereby helping to improve the electromechanical coupling coefficient of the resonance device and the Q value of the resonance device. In addition, when forming the two electrode layers, the operating frequency of the resonance device can be controlled by adjusting the width of the plurality of electrode strips or the spacing distance therebetween. In addition, the intermediate layer having a smaller acoustic impedance than the piezoelectric layer can be used to block sound waves from leaking from the resonance zone into the second substrate. In addition, providing a thin film between the intermediate layer and the second substrate helps to prevent the formation of a free electron layer on the surface of the second substrate, thereby reducing the electrical loss caused by the second substrate.

[0391] It should be understood that the examples and embodiments herein are merely illustrative and that various modifications and corrections may be made by those skilled in the art without departing from the spirit and scope of the present invention as defined in this application and the appended claims.

Claims

1. A bulk acoustic wave resonance device, characterized in that: include: a first layer including a cavity on a first side; A first electrode layer, located in the cavity; a second layer, located on the first side and on the first electrode layer, the second layer being a flat layer and covering the cavity, the second layer comprising: a piezoelectric layer, the piezoelectric layer comprising a plurality of crystals, the plurality of crystals comprising a first crystal and a second crystal, wherein the first crystal and the second crystal are any two crystals of the plurality of crystals, a first coordinate axis along the first direction corresponds to a height of the first crystal, and a second coordinate axis along the second direction corresponds to a height of the second crystal, wherein the first direction and the second direction are the same or opposite; and a second electrode layer, located on the first side and on the second layer, wherein the first electrode layer comprises at least two first electrode strips or the second electrode layer comprises at least two second electrode strips.

2. The bulk acoustic wave resonator device according to claim 1, characterized in that: The first electrode layer includes a first polarity, and the second electrode layer includes a second polarity.

3. The bulk acoustic wave resonator device according to claim 2, characterized in that: The at least two first electrode strips comprise the first polarity.

4. The bulk acoustic wave resonator device according to claim 2, characterized in that: The at least two second electrode strips comprise the second polarity.

5. The bulk acoustic wave resonator device according to claim 1, characterized in that: The first electrode layer includes a first polarity and a second polarity, and the second electrode layer includes the first polarity and the second polarity.

6. The bulk acoustic wave resonator device according to claim 5, characterized in that: The at least two first electrode strips include the first polarity and the second polarity, and the at least two second electrode strips include the first polarity and the second polarity, wherein the first electrode strips and the second electrode strips corresponding to the two sides of the second layer include the first polarity and the second polarity respectively.

7. The bulk acoustic wave resonator device according to claim 5, characterized in that: The first polarity and the second polarity are arranged alternately.

8. The bulk acoustic wave resonator device according to claim 1, characterized in that: The at least two first electrode strips include at least one first duty cycle, and a value range of the at least one first duty cycle includes 0.1 to 1.

9. The bulk acoustic wave resonator device according to claim 1, characterized in that: The at least two second electrode strips include at least one second duty cycle, and a value range of the at least one second duty cycle includes 0.1 to 1.

10. The bulk acoustic wave resonator device according to claim 1, characterized in that: The spacing distance between two adjacent first electrode strips is consistent, including the first distance.

11. The bulk acoustic wave resonator device according to claim 1, characterized in that: The spacing distance between two adjacent second electrode strips is consistent, including the second distance.

12. The bulk acoustic wave resonator device according to claim 1, characterized in that: The distance between two adjacent first electrode strips varies, and includes at least a third distance and a fourth distance.

13. The bulk acoustic wave resonator device according to claim 1, characterized in that: The distance between two adjacent second electrode strips varies, and includes at least a fifth distance and a sixth distance.

14. The bulk acoustic wave resonator device according to claim 1, characterized in that: The widths of the at least two first electrode strips are consistent, including the first width.

15. The bulk acoustic wave resonator device according to claim 1, characterized in that: The widths of the at least two second electrode strips are consistent, including the second width.

16. The BAW resonator device according to claim 1, characterized in that: The widths of the at least two first electrode strips vary, and include at least a third width and a fourth width.

17. The BAW resonator device according to claim 1, characterized in that: The widths of the at least two second electrode strips vary, and include at least a fifth width and a sixth width.

18. The bulk acoustic wave resonator device according to claim 1, characterized in that: The overlapping portion of the second electrode layer and the first electrode layer is located above the cavity, and a projection of the overlapping portion perpendicular to the first layer is located within the cavity.

19. The BAW resonator device according to claim 1, characterized in that: The material of the first electrode layer includes at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum; the material of the second electrode layer includes at least one of the following: molybdenum, ruthenium, tungsten, platinum, iridium, and aluminum.

20. The bulk acoustic wave resonator device according to claim 1, characterized in that: The first layer further includes: an intermediate layer, wherein the intermediate layer includes the cavity.

21. The BAW resonator device according to claim 20, characterized in that: The material of the intermediate layer includes at least one of the following: a polymer and an insulating dielectric.

22. The BAW resonator device according to claim 21, characterized in that: The polymer includes at least one of the following: benzocyclobutene, photosensitive epoxy resin photoresist, and polyimide.

23. The BAW resonator device according to claim 21, characterized in that: The insulating dielectric includes at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

24. The BAW resonator device according to claim 20, characterized in that: The thickness of the intermediate layer is in a range of 0.1 micrometers to 10 micrometers.

25. The BAW resonator device according to claim 1, characterized in that: The first layer further includes: a supporting layer, wherein the supporting layer includes the cavity.

26. The bulk acoustic wave resonator device according to claim 25, characterized in that: The material of the support layer includes at least one of the following: polymer, insulating dielectric.

27. The BAW resonator device according to claim 26, characterized in that: The polymer includes at least one of the following: benzocyclobutene, photosensitive epoxy resin photoresist, and polyimide.

28. The BAW resonator device according to claim 26, characterized in that: The insulating dielectric includes at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

29. The BAW resonator device according to claim 25, characterized in that: The thickness of the support layer is in a range of 20 micrometers to 100 micrometers.

30. The BAW resonator device according to claim 1, characterized in that: The first layer further includes: a first substrate including the cavity.

31. The BAW resonator device according to claim 30, characterized in that: The material of the first substrate includes at least one of the following: silicon, silicon carbide, and glass.

32. The BAW resonator device according to claim 1, characterized in that: The first layer further includes: an etching shielding layer, which at least covers the bottom or side wall of the cavity.

33. The BAW resonator device according to claim 32, characterized in that: The material of the etching shielding layer includes at least one of the following: aluminum nitride, silicon carbide, diamond, silicon nitride, silicon dioxide, aluminum oxide, and titanium dioxide.

34. The BAW resonator device according to claim 32, characterized in that: The thickness of the etching shielding layer ranges from 0.1 micrometer to 3 micrometers.

35. The BAW resonator device according to claim 32, characterized in that: The thickness of the etching shielding layer ranges from 2 microns to 6 microns.

36. The BAW resonator device according to claim 1, characterized in that: The first crystal corresponds to a first coordinate system, which includes the first coordinate axis and a third coordinate axis along a third direction; the second crystal corresponds to a second coordinate system, which includes the second coordinate axis and a fourth coordinate axis along a fourth direction.

37. The BAW resonator device according to claim 36, characterized in that: The first coordinate system further includes a fifth coordinate axis along a fifth direction, and the second coordinate system further includes a sixth coordinate axis along a sixth direction.

38. The BAW resonator device according to claim 37, characterized in that: The third direction is the same as or opposite to the fourth direction.

39. The BAW resonator device according to claim 1, characterized in that: The material of the piezoelectric layer includes at least one of the following: aluminum nitride, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, and lead magnesium niobate-lead titanate.

40. The BAW resonator device according to claim 1, characterized in that: The second layer includes: a piezoelectric layer, the piezoelectric layer includes a plurality of crystals, and the half-peak width of a rocking curve of a crystal composed of the plurality of crystals is less than 2.5 degrees.

41. The BAW resonator device according to claim 1, characterized in that: Also includes: The second substrate is located on a second side of the first layer, and the second side is opposite to the first side.

42. The BAW resonator device according to claim 41, characterized in that: The material of the second substrate includes at least one of the following: silicon, silicon carbide, and glass.

43. The BAW resonator device according to claim 41, characterized in that: Also includes: A film is disposed between the first layer and the second substrate.

44. The BAW resonator device according to claim 43, characterized in that: The thin film includes: a polycrystalline thin film.

45. The BAW resonator device according to claim 44, characterized in that: The material of the polycrystalline thin film includes at least one of the following: polycrystalline silicon, polycrystalline silicon nitride, and polycrystalline silicon carbide.

46. ​​A bulk acoustic wave filter device, characterized in that: include: At least one BAW resonator device as claimed in any one of claims 1 to 45.

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