Bulk acoustic wave resonance device, forming method thereof and filter

Abstract

The invention discloses a bulk acoustic wave resonance device, a forming method thereof and a filter. An intermediate layer on the substrate, the intermediate layer including a cavity and a crystal defect, the crystal defect including one or more of a point defect, a line defect, and a surface defect; the piezoelectric layer is located on the middle layer, the piezoelectric layer comprises a first side and a second side which are opposite to each other, and the middle layer and the substrate are located on the first side; the first electrode layer is located on the first side of the piezoelectric layer; the second electrode layer is located on the second side of the piezoelectric layer, and the projection of the first electrode layer and the projection of the second electrode layer towards the direction of the substrate have an overlapped area. The crystal defect in the middle layer can form a charge trap, and a conductive plane can be prevented from being formed on the surface of the substrate, so that the generated parasitic coupling phenomenon is effectively inhibited, the electric loss is reduced, and the Q value of the resonance device or the electromechanical coupling coefficient (Kt) of the resonance device is improved.

Description

Technical Field

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

[0002] The RF front-end chips of wireless communication devices include power amplifiers, antenna switches, RF filters, multiplexers, and low-noise amplifiers, etc. 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.

[0003] The quality factor (Q value) of surface acoustic wave resonators and bulk acoustic wave resonators is relatively high. The low insertion loss and high out-of-band suppression RF filters made of surface acoustic wave resonators and bulk acoustic wave resonators, namely surface acoustic wave filters and bulk acoustic wave filters, are the mainstream RF filters currently used in wireless communication devices 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 surface acoustic wave filters is generally 0.4GHz to 2.7GHz, and the operating frequency of bulk acoustic wave filters is generally 0.7GHz to 7GHz.

[0004] 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 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.

[0005] However, there are still many problems with BAW devices. Summary of the invention

[0006] The problem solved by the present invention is to provide a bulk acoustic wave resonator device and a forming method thereof, and a filter, so as to improve the Q value of the resonator device or the electromechanical coupling coefficient (Kt) of the resonator device.

[0007] To solve the above problems, the technical solution of the present invention provides a bulk acoustic wave resonance device, comprising: a substrate; an intermediate layer, located on the substrate, the intermediate layer including cavities and crystal defects, the crystal defects including: one or more of point defects, line defects and surface defects; a piezoelectric layer, located on the intermediate layer, the piezoelectric layer including a first side and a second side opposite to each other, the intermediate layer and the substrate being located on the first side; a first electrode layer, located on the first side of the piezoelectric layer; a second electrode layer, located on the second side of the piezoelectric layer, the projections of the first electrode layer and the second electrode layer toward the substrate having an overlapping area.

[0008] Optionally, at least one end of the first electrode layer is located in the cavity.

[0009] Optionally, the first electrode layer is located on the intermediate layer, and the first electrode layer covers the cavity.

[0010] Optionally, the cavity and the crystal defect are located on two opposite sides of the intermediate layer, the cavity is located between the crystal defect and the piezoelectric layer, and the crystal defect is located between the cavity and the substrate.

[0011] Optionally, the intermediate layer includes a first portion located between the cavity and the substrate, and a second portion located between the first portion and the piezoelectric layer, and the crystal defect is located in a side of the first portion close to the substrate.

[0012] Optionally, the point defect includes: a vacancy defect or an impurity defect.

[0013] Optionally, the vacancy defect includes: a Frankel vacancy or a Schottky vacancy.

[0014] Optionally, the impurity defects include: interstitial impurities or substitutional impurities.

[0015] Optionally, the line defect includes: a dislocation defect.

[0016] Optionally, the dislocation defect includes: edge dislocation or screw dislocation.

[0017] Optionally, the surface defect includes: a translation interface, a twin interface or a grain boundary.

[0018] Optionally, the translation interface includes: surface state defects.

[0019] Optionally, the surface state defects include: reconstructed atoms or relaxed surfaces.

[0020] Optionally, the material of the intermediate layer includes: silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound obtained by adding fluorine, carbon or boron to silicon dioxide, or any one of materials with the above materials as main components.

[0021] Correspondingly, the technical solution of the present invention also provides a method for forming a bulk acoustic wave resonance device, including: providing a substrate; forming a piezoelectric layer, the piezoelectric layer includes a first side and a second side opposite to each other, the substrate is located on the first side; forming a first electrode layer, the first electrode layer is located on the first side; forming an intermediate layer, located between the substrate and the piezoelectric layer, the intermediate layer includes a cavity and a crystal defect, the intermediate layer is located on the first side, and the crystal defect includes: one or more of a point defect, a line defect and a surface defect; forming a second electrode layer, the second electrode layer is located on the second side, and the projections of the first electrode layer and the second electrode layer toward the substrate have an overlapping area.

[0022] Optionally, the method for forming the intermediate layer includes: forming a cavity pretreatment layer on the piezoelectric layer, the cavity pretreatment layer is used to form the cavity, the cavity pretreatment layer covers the first electrode layer, the cavity pretreatment layer is located on the first side, and forming the cavity pretreatment layer includes forming a sacrificial layer and a first bonding layer, the sacrificial layer at least covers a portion of the first electrode layer, and the first bonding layer at least covers the sacrificial layer.

[0023] Optionally, the method of forming the first bonding layer includes: forming the crystal defect in the first bonding layer.

[0024] Optionally, the crystal defect and the sacrificial layer are located on two opposite sides of the first bonding layer, and the sacrificial layer is located between the crystal defect and the piezoelectric layer.

[0025] Optionally, the method of forming the intermediate layer further includes: bonding the cavity pretreatment layer and the substrate.

[0026] Optionally, bonding the cavity pretreatment layer and the substrate includes: bonding the first bonding layer and the substrate, wherein bonding surfaces of the first bonding layer and the substrate have the crystal defects.

[0027] Optionally, the method for forming the intermediate layer further includes: forming a second bonding layer on the substrate; and bonding the cavity pretreatment layer and the second bonding layer.

[0028] Optionally, bonding the cavity pretreatment layer and the second bonding layer includes: bonding the first bonding layer and the second bonding layer, the first bonding layer and the second bonding layer being made of the same material.

[0029] Optionally, a bonding surface between the cavity pretreatment layer and the second bonding layer has the crystal defect.

[0030] Optionally, the method of forming the second bonding layer includes: forming the crystal defect in the second bonding layer.

[0031] Optionally, the method for forming the intermediate layer further includes: removing the sacrificial layer to form the cavity.

[0032] Correspondingly, the technical solution of the present invention further provides a filter, characterized in that it includes: a bulk acoustic wave resonance device as described in any one of the technical solutions above.

[0033] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0034] In the bulk acoustic wave resonator of the technical solution of the present invention, the crystal defects in the intermediate layer can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0035] Furthermore, the cavity and the crystal defect are located on opposite sides of the intermediate layer, the cavity is located between the crystal defect and the piezoelectric layer, and the crystal defect is located between the cavity and the substrate, which can keep the crystal defect away from the piezoelectric layer, further suppress the parasitic coupling phenomenon generated between the piezoelectric layer and the substrate, reduce electrical losses, and thereby improve the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0036] In the method for forming a bulk acoustic wave resonator device of the technical solution of the present invention, the crystal defects in the intermediate layer can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses to improve the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0037] Furthermore, the crystal defect and the sacrificial layer are located on opposite sides of the first bonding layer, and the sacrificial layer is located between the crystal defect and the piezoelectric layer. By arranging the crystal defect and the sacrificial layer to be located on opposite sides of the first bonding layer, after the subsequent removal of the sacrificial layer, the formed cavity and the crystal defect are located on opposite sides of the intermediate layer, the cavity is located between the crystal defect and the piezoelectric layer, and the crystal defect is located between the cavity and the substrate, so that the crystal defect can be kept away from the piezoelectric layer, further suppressing the parasitic coupling phenomenon generated between the piezoelectric layer and the substrate, reducing electrical losses, and improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the structure of a bulk acoustic wave resonance device;

[0039] Figures 2 to 8 is a structural schematic diagram of each step of a method for forming a bulk acoustic wave resonator device in an embodiment of the present invention;

[0040] Fig. 9 Schematic diagram of a defect of a Frankel vacancy in an embodiment of the present invention;

[0041] Fig.10 is a schematic diagram of a defect of a Schottky vacancy in another embodiment of the present invention;

[0042] Figures 11 to 18 is a structural schematic diagram of each step of a method for forming a bulk acoustic wave resonator device in another embodiment of the present invention;

[0043] Fig.19 is a schematic diagram of defects of interstitial impurities in another embodiment of the present invention;

[0044] Fig. 20 is a schematic diagram of defects of substitutional impurities in another embodiment of the present invention;

[0045] Fig.21 is a schematic diagram of an edge dislocation defect in another embodiment of the present invention;

[0046] Fig. 22 is a schematic diagram of a screw dislocation defect in another embodiment of the present invention;

[0047] Fig.23 is a schematic diagram of defects in reconstructing atoms in another embodiment of the present invention;

[0048] Fig.24 is a schematic diagram of defects on a relaxed surface in another embodiment of the present invention;

[0049] Fig.25 is a schematic structural diagram of a bulk acoustic wave resonance device in another embodiment of the present invention;

[0050] Fig.26 It is a schematic structural diagram of a bulk acoustic wave resonance device in another embodiment of the present invention. DETAILED DESCRIPTION

[0051] As described in the background art, there are still many problems with the BAW resonator, which will be described in detail below with reference to the accompanying drawings.

[0052] Figure 1 It is a structural schematic diagram of a bulk acoustic wave resonance device.

[0053] Please refer to Figure 1A bulk acoustic wave resonance device comprises: a substrate 100; an intermediate layer 101, located on the substrate 100, the intermediate layer 101 comprising a cavity 102; a piezoelectric layer 103, located on the intermediate layer 101, the piezoelectric layer 103 comprising a first side 103a and a second side 103b opposite to each other, the intermediate layer 101 and the substrate 100 being located on the first side 103a; a first electrode layer 104, located on the first side 103a of the piezoelectric layer 103; a second electrode layer 105, located on the second side 103b of the piezoelectric layer 103, the projections of the first electrode layer 104 and the second electrode layer 105 towards the substrate 100 having an overlapping area.

[0054] In this embodiment, the material of the intermediate layer 101 includes: silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound obtained by adding fluorine, carbon or boron to silicon dioxide, or any one of the materials with the above materials as the main components.

[0055] However, there is a parasitic surface conductivity effect (PSC) at the interface between the intermediate layer 101 and the substrate 100 made of the above material, and parasitic coupling occurs between the piezoelectric layer 103 and the substrate 100, resulting in electrical loss, thereby reducing the Q value or electromechanical coupling coefficient (Kt).

[0056] On this basis, the present invention provides a bulk acoustic wave resonator device and a method for forming the same, as well as a filter. The crystal defects in the intermediate layer can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0057] 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.

[0058] 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.

[0059] Figures 2 to 8 is a structural schematic diagram of each step of a method for forming a bulk acoustic wave resonator device in an embodiment of the present invention; Fig. 9 Schematic diagram of a defect of a Frankel vacancy in an embodiment of the present invention; Fig.10 Schematic diagram of a defect of a Schottky vacancy in another embodiment of the present invention.

[0060] Please refer to Figure 2, providing a substrate 200.

[0061] It should be noted that, in this embodiment, the substrate 200 mainly plays a supporting role in the subsequent device manufacturing process, and the substrate 200 is made of a material with a resistivity higher than 1000 ohm / cm.

[0062] The material of the substrate 200 includes: single crystal silicon, glass, sapphire, and silicon carbide.

[0063] In this embodiment, the substrate 200 is made of single crystal silicon.

[0064] After providing the substrate 200, the method further includes: forming a piezoelectric layer, the piezoelectric layer including a first side and a second side opposite to each other, the substrate 200 being located on the first side; forming a first electrode layer, the first electrode layer being located on the first side; forming an intermediate layer, located between the substrate 200 and the piezoelectric layer, the intermediate layer including cavities and crystal defects, the intermediate layer being located on the first side, the crystal defects including: one or more of point defects, line defects and surface defects; forming a second electrode layer, the second electrode layer being located on the second side, the projections of the first electrode layer and the second electrode layer toward the substrate 200 having an overlapping area. For the specific formation process of the piezoelectric layer, the intermediate layer, the first electrode layer and the second electrode layer, please refer to Figures 3 to 8 .

[0065] Please refer to Figure 3 , providing a sacrificial substrate 201.

[0066] It should be noted that, in this embodiment, the sacrificial substrate 201 is used as a temporary support in the process of forming the bulk acoustic wave resonator device. After the different parts are joined together, the sacrificial substrate 201 needs to be removed.

[0067] Please refer to Figure 4 A piezoelectric layer 202 is formed on the sacrificial substrate 201 , wherein the piezoelectric layer 202 includes a first side 202 a and a second side 202 b opposite to each other, and the sacrificial substrate 201 is located on the second side 202 b .

[0068] The material of the piezoelectric layer 202 includes, but is not limited to, at least one of the following: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, and lead magnesium niobate-lead titanate.

[0069] Please refer to Figure 5 , forming a first electrode layer 203, wherein the first electrode layer 203 is located at the first side 202a.

[0070] The material of the first electrode layer 203 includes, but is not limited to, at least one of the following: molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0071] In this embodiment, a protection layer (not shown) is formed on the surface of the first electrode layer 203 to enhance the protection of the first electrode layer 203 .

[0072] After forming the first electrode layer 203, the intermediate layer is formed, and the intermediate layer includes: a first bonding layer and the cavity located in the first bonding layer. For the specific formation process of the intermediate layer, please refer to Figures 6 to 8 .

[0073] Please refer to Figure 6 , a cavity pretreatment layer 204 is formed on the piezoelectric layer 202, the cavity pretreatment layer 204 is used to form the cavity, the cavity pretreatment layer 204 covers the first electrode layer 203, the cavity pretreatment layer 204 is located on the first side 202a, and the formation of the cavity pretreatment layer 204 includes forming a sacrificial layer 2042 and the first bonding layer 2041.

[0074] In this embodiment, the sacrificial layer 2042 covers one end of the first electrode layer 203 , and the first bonding layer 2041 at least covers the sacrificial layer 2042 .

[0075] In other embodiments, the sacrificial layer may also completely cover the first electrode layer, that is, the sacrificial layer covers two opposite ends of the first electrode layer.

[0076] It should be noted that, in this embodiment, the sacrificial layer 2042 is used to form an advance placeholder for the cavity, and the sacrificial layer 2042 needs to be removed in a subsequent process to form the cavity.

[0077] In this embodiment, the method for forming the first bonding layer 2041 includes: forming the crystal defect in the first bonding layer 2041 .

[0078] The crystal defects in the intermediate layer can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate 200, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0079] In this embodiment, the crystal defect and the sacrificial layer 2042 are located on two opposite sides of the first bonding layer 2041 , and the sacrificial layer 2042 is located between the crystal defect and the piezoelectric layer 202 .

[0080] The material of the first bonding layer 2041 includes: silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound obtained by adding fluorine, carbon or boron to silicon dioxide, or any one of the materials having the above materials as main components.

[0081] It should be noted that since the first bonding layer 2041 is part of the intermediate layer, the corresponding material of the intermediate layer also includes: silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound formed by adding fluorine, carbon or boron to silicon dioxide, or any one of the materials with the above materials as the main components.

[0082] In this embodiment, the material of the first bonding layer 2041 is silicon dioxide.

[0083] The crystal defects include: one or more of point defects, line defects and surface defects.

[0084] It should be noted that the crystal defects can be formed by common process methods used by those skilled in the art. There are many factors affecting the formation of the crystal defects, such as ion implantation and thermal diffusion, which can both produce crystal point defects.

[0085] Among them, atoms or molecules are ionized to form plasma, which carries a certain amount of charge. The ions are accelerated by the electric field and the magnetic field is used to change their direction of movement, so that the ions can be controlled to enter the crystal with a certain energy. This process will cause a large number of point defects such as vacancies and gaps in the crystal, as well as complex defects formed by vacancies combined with other impurities. The formation of defects is related to the energy, mass, dose, target material and target temperature of the injected ions.

[0086] Crystal defects can also be generated by thermal diffusion, which is divided into interstitial diffusion and substitutional diffusion. At high temperatures, lattice atoms vibrate near the lattice equilibrium position, and matrix atoms have a certain probability of obtaining enough energy to break away from the lattice and become interstitial atoms, creating a vacancy. At this time, the adjacent impurity atoms can occupy this vacancy. This is substitutional diffusion. If the interstitial impurity atoms move from one position to another and do not occupy the lattice point, this is interstitial diffusion. Vacancy defects and impurity defects are easily generated during the diffusion process.

[0087] In this embodiment, the crystal defect is a point defect, and the point defect is a vacancy defect.

[0088] Please refer to Fig. 9 In this embodiment, the vacancy defect is a Frankel vacancy.

[0089] Please refer to Fig.10 In other embodiments, the vacancy defect may also be a Schottky vacancy.

[0090] Please refer to Figure 7 , bonding the cavity pretreatment layer 204 and the substrate 200; after bonding the cavity pretreatment layer 204 and the substrate 200, removing the sacrificial layer 2042 to form the cavity 205, and the cavity 205 and the first bonding layer 2041 form the intermediate layer.

[0091] By adding the intermediate layer and the substrate 200 below the piezoelectric layer 202, the two will have a difference in acoustic impedance due to different materials, which can effectively prevent energy from leaking downward, thereby improving the Q value of the resonant device. Since the intermediate layer and the substrate 200 are solid materials, their heat transfer coefficient is greater than the heat transfer coefficient of air, which can improve the heat dissipation of the resonant device, increase the power capacity of the resonant device, and improve the performance of the resonant device.

[0092] In this embodiment, bonding the cavity pretreatment layer 204 and the substrate 200 includes: bonding the first bonding layer 2041 and the substrate 200, wherein the bonding surfaces of the first bonding layer 2041 and the substrate 200 also have the crystal defects.

[0093] In other embodiments, the bonding surface between the first bonding layer and the substrate may not have the crystal defects.

[0094] In this embodiment, one end of the first electrode layer 203 is located in the cavity 205 .

[0095] In other embodiments, when the sacrificial layer covers two ends of the first electrode layer, the corresponding two ends of the first electrode layer are both located in the cavity.

[0096] In this embodiment, the cavity 205 and the crystal defect are located on opposite sides of the first bonding layer 2041, the cavity 205 is located between the crystal defect and the piezoelectric layer 202, and the crystal defect is located between the cavity 205 and the substrate 200. The crystal defect can be kept away from the piezoelectric layer 202, further suppressing the parasitic coupling phenomenon generated between the piezoelectric layer 202 and the substrate 200, reducing electrical losses, and improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0097] In this embodiment, after the first bonding layer 2041 and the substrate 200 are bonded, the sacrificial substrate 201 is removed.

[0098] Please refer to Figure 8After removing the sacrificial substrate 201 , a second electrode layer 206 is formed, the second electrode layer 206 is located on the second side 202 b , and projections of the first electrode layer 203 and the second electrode layer 206 toward the substrate 200 have an overlapping area.

[0099] In this embodiment, the material of the second electrode layer 206 includes but is not limited to at least one of the following: molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0100] In this embodiment, a protection layer (not shown) is formed on the surface of the second electrode layer 206 to enhance the protection of the second electrode layer 206 .

[0101] Correspondingly, a bulk acoustic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Figure 8 , including: a substrate 200; an intermediate layer, located on the substrate 200, the intermediate layer including a cavity 205 and a crystal defect, the crystal defect including: one or more of a point defect, a line defect and a surface defect; a piezoelectric layer 202, located on the intermediate layer, the piezoelectric layer 202 including a first side 202a and a second side 202b opposite to each other, the intermediate layer and the substrate 200 are located on the first side 202a; a first electrode layer 203, located on the first side 202a of the piezoelectric layer 202; a second electrode layer 206, located on the second side 202b of the piezoelectric layer 202, the projections of the first electrode layer 203 and the second electrode layer 206 toward the substrate 200 have an overlapping area.

[0102] By adding the intermediate layer and the substrate 200 below the piezoelectric layer 202, the two will have a difference in acoustic impedance due to different materials, which can effectively prevent energy from leaking downward, thereby improving the Q value of the resonant device. Since the intermediate layer and the substrate 200 are solid materials, their heat transfer coefficient is greater than the heat transfer coefficient of air, which can improve the heat dissipation of the resonant device, increase the power capacity of the resonant device, and improve the performance of the resonant device.

[0103] In addition, the crystal defects in the intermediate layer can form charge traps, thereby preventing the formation of a conductive plane on the surface of the substrate 200, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0104] In this embodiment, the crystal defect is a point defect, and the point defect is a vacancy defect.

[0105] Please continue to refer to Fig. 9 In this embodiment, the vacancy defect is a Frankel vacancy.

[0106] Please continue to refer to Fig.10 In other embodiments, the vacancy defect may also be a Schottky vacancy.

[0107] In this embodiment, the intermediate layer includes: a first bonding layer 2041 , and the cavity 205 located in the first bonding layer 2041 , and the first bonding layer 2041 is bonded to the substrate 200 .

[0108] In this embodiment, the first bonding layer 2041 has the crystal defects therein.

[0109] The material of the first bonding layer 2041 includes: silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound obtained by adding fluorine, carbon or boron to silicon dioxide, or any one of the materials having the above materials as main components.

[0110] It should be noted that since the first bonding layer 2041 is part of the intermediate layer, the corresponding material of the intermediate layer also includes: silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound formed by adding fluorine, carbon or boron to silicon dioxide, or any one of the materials with the above materials as the main components.

[0111] In this embodiment, the material of the first bonding layer 2041 is silicon dioxide.

[0112] In this embodiment, the bonding surface between the first bonding layer 2041 and the substrate 200 also has the crystal defects.

[0113] In other embodiments, the bonding surface between the first bonding layer and the substrate may not have the crystal defects.

[0114] In this embodiment, one end of the first electrode layer 203 is located in the cavity 205 .

[0115] In other embodiments, both ends of the first electrode layer may be located in the cavity.

[0116] In this embodiment, the cavity 205 and the crystal defect are located on opposite sides of the intermediate layer, the cavity 205 is located between the crystal defect and the piezoelectric layer 202, and the crystal defect is located between the cavity 205 and the substrate 200. The crystal defect can be kept away from the piezoelectric layer 202, further suppressing the parasitic coupling phenomenon generated between the piezoelectric layer 202 and the substrate 200, reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0117] In this embodiment, the present invention further includes: a protection layer (not shown) located on the surface of the second electrode layer 206 to enhance the protection of the second electrode layer 206 .

[0118] In this embodiment, it further includes: a protection layer (not shown) located on the surface of the first electrode layer 203 to enhance the protection of the first electrode layer 203 .

[0119] In this embodiment, the intermediate layer includes a first portion 207 located between the cavity 205 and the substrate 200 , and a second portion 208 located between the first portion 207 and the piezoelectric layer 202 , and the crystal defect is located in a side of the first portion 207 close to the substrate 200 .

[0120] Figures 11 to 18 It is a structural schematic diagram of each step of a method for forming a bulk acoustic wave resonator device in another embodiment of the present invention.

[0121] Please refer to Fig.11 , providing a substrate 300.

[0122] It should be noted that, in this embodiment, the substrate 300 mainly plays a supporting role in the subsequent device manufacturing process, and the substrate 300 is made of a material with a resistivity higher than 1000 ohm / cm.

[0123] The material of the substrate 300 includes: single crystal silicon, glass, sapphire, and silicon carbide.

[0124] In this embodiment, the substrate 300 is made of single crystal silicon.

[0125] After providing the substrate 300, the method further includes: forming a piezoelectric layer, the piezoelectric layer including a first side and a second side opposite to each other, the substrate 300 being located on the first side; forming a first electrode layer, the first electrode layer being located on the first side; forming an intermediate layer, located between the substrate 300 and the piezoelectric layer, the intermediate layer including cavities and crystal defects, the intermediate layer being located on the first side, the crystal defects including: one or more of point defects, line defects and surface defects; forming a second electrode layer, the second electrode layer being located on the second side, the projections of the first electrode layer and the second electrode layer toward the substrate 300 having an overlapping area. For the specific formation process of the piezoelectric layer, the intermediate layer, the first electrode layer and the second electrode layer, please refer to Figures 12 to 18 .

[0126] Please refer to Fig.12 , providing a sacrificial substrate 301.

[0127] It should be noted that, in this embodiment, the sacrificial substrate 301 is used as a temporary support in the process of forming the bulk acoustic wave resonator device. After the different parts are joined together, the sacrificial substrate 301 needs to be removed.

[0128] Please refer to Fig.13 A piezoelectric layer 302 is formed on the sacrificial substrate 301 , wherein the piezoelectric layer 302 includes a first side 302 a and a second side 302 b opposite to each other, and the sacrificial substrate 301 is located on the second side 302 b .

[0129] The material of the piezoelectric layer 302 includes, but is not limited to, at least one of the following: aluminum nitride, aluminum nitride alloy, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, and lead magnesium niobate-lead titanate.

[0130] Please refer to Fig.14 , forming a first electrode layer 303, wherein the first electrode layer 303 is located at the first side 302a.

[0131] The material of the first electrode layer 303 includes, but is not limited to, at least one of the following: molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0132] In this embodiment, a protection layer (not shown) is formed on the surface of the first electrode layer 303 to enhance the protection of the first electrode layer 303 .

[0133] After forming the first electrode layer 303, the intermediate layer is formed, and the intermediate layer includes: a first bonding layer, a second bonding layer, and the cavity located in the first bonding layer. For the specific formation process of the intermediate layer, please refer to Figures 15 to 18 .

[0134] Please refer to Fig.15 , a cavity pretreatment layer 304 is formed on the piezoelectric layer 302, the cavity pretreatment layer 304 is used to form the cavity, the cavity pretreatment layer 304 covers the first electrode layer 303, the cavity pretreatment layer 304 is located on the first side 302a, and the formation of the cavity pretreatment layer 304 includes forming a sacrificial layer 3042 and the first bonding layer 3041.

[0135] In this embodiment, the sacrificial layer 3042 at least covers a portion of one end of the first electrode layer 303 , and the first bonding layer 3041 at least covers the sacrificial layer 3042 .

[0136] It should be noted that, in the present embodiment, the sacrificial layer 3042 is used to form an advance placeholder for the cavity, and the sacrificial layer 3042 needs to be removed in a subsequent process to form the cavity.

[0137] The material of the first bonding layer 3041 includes silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound obtained by adding fluorine, carbon or boron to silicon dioxide, or any one of the materials having the above materials as main components.

[0138] In this embodiment, the material of the first bonding layer 3041 is silicon dioxide.

[0139] Please refer to Fig.16 , forming the second bonding layer 305 on the substrate 300 .

[0140] In this embodiment, the first bonding layer 3041 and the second bonding layer 305 are made of the same material.

[0141] The material of the second bonding layer 305 includes silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound obtained by adding fluorine, carbon or boron to silicon dioxide, or any one of materials having the above materials as main components.

[0142] In this embodiment, the second bonding layer 305 is made of silicon dioxide.

[0143] In this embodiment, the crystal defects are formed in the second bonding layer 305 .

[0144] The crystal defects include: one or more of point defects, line defects and surface defects.

[0145] It should be noted that the crystal defects can be formed by common process methods used by those skilled in the art. There are many factors affecting the formation of the crystal defects, such as ion implantation and thermal diffusion, which can both produce crystal point defects.

[0146] Among them, atoms or molecules are ionized to form plasma, which carries a certain amount of charge. The ions are accelerated by the electric field and the magnetic field is used to change their direction of movement, so that the ions can be controlled to enter the crystal with a certain energy. This process will cause a large number of point defects such as vacancies and gaps in the crystal, as well as complex defects formed by vacancies combined with other impurities. The formation of defects is related to the energy, mass, dose, target material and target temperature of the injected ions.

[0147] Crystal defects can also be generated by thermal diffusion, which is divided into interstitial diffusion and substitutional diffusion. At high temperatures, lattice atoms vibrate near the lattice equilibrium position, and matrix atoms have a certain probability of obtaining enough energy to break away from the lattice and become interstitial atoms, creating a vacancy. At this time, the adjacent impurity atoms can occupy this vacancy. This is substitutional diffusion. If the interstitial impurity atoms move from one position to another and do not occupy the lattice point, this is interstitial diffusion. Vacancy defects and impurity defects are easily generated during the diffusion process.

[0148] In this embodiment, the crystal defect is a point defect, and the point defect is a vacancy defect.

[0149] Please continue to refer to Fig. 9 In this embodiment, the vacancy defect is a Frankel vacancy.

[0150] Please continue to refer to Fig.10 In other embodiments, the vacancy defect may also be a Schottky vacancy.

[0151] Please refer to Fig.17 , bonding the cavity pretreatment layer 304 and the second bonding layer 305, including: bonding the first bonding layer 3041 and the second bonding layer 305; after bonding the first bonding layer 3041 and the second bonding layer 305, removing the sacrificial layer 3042 to form the cavity 306, and the cavity 306, the first bonding layer 3041 and the second bonding layer 305 form an intermediate layer 308.

[0152] It should be noted that since the first bonding layer 3041 and the second bonding layer 305 are both part of the intermediate layer 308, the corresponding material of the intermediate layer 308 also includes: silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound formed by adding fluorine, carbon or boron to silicon dioxide, or any one of the materials with the above materials as the main components.

[0153] The crystal defects in the intermediate layer 308 can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate 300, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0154] In addition, by adding the intermediate layer 308 and the substrate 300 below the piezoelectric layer 302, the two will have a difference in acoustic impedance due to different materials, which can effectively prevent energy from leaking downward, thereby improving the Q value of the resonant device. Since the intermediate layer 308 and the substrate 300 are solid materials, their heat transfer coefficient is greater than the heat transfer coefficient of air, which can improve the heat dissipation of the resonant device, increase the power capacity of the resonant device, and improve the performance of the resonant device.

[0155] In this embodiment, the cavity 306 and the crystal defect are located on opposite sides of the intermediate layer 308 , the cavity 306 is located between the crystal defect and the piezoelectric layer 302 , and the crystal defect is located between the cavity 306 and the substrate 300 .

[0156] In this embodiment, one end of the first electrode layer 303 is located in the cavity 306 .

[0157] In other embodiments, both ends of the first electrode layer may be located in the cavity.

[0158] It should be noted that whether the end of the first electrode layer 303 is located in the cavity 306 depends on whether the sacrificial layer 3042 covers the end of the first electrode layer 303 when the sacrificial layer 3042 is formed.

[0159] In this embodiment, after the first bonding layer 3041 and the second bonding layer 305 are bonded, the sacrificial substrate 301 is removed.

[0160] In this embodiment, the first bonding layer 3041 and the second bonding layer 305 are directly bonded using a silicon base.

[0161] In this embodiment, the crystal defect is formed in a side of the second bonding layer 305 close to the substrate 300 .

[0162] In other embodiments, the bonding surface of the first bonding layer and the second bonding layer may further have the crystal defect.

[0163] In other embodiments, the crystal defects may be formed in both the first bonding layer and the second bonding layer.

[0164] In other embodiments, the crystal defect may be formed only in the first bonding layer. Preferably, the crystal defect is formed in a side of the first bonding layer close to the second bonding layer, and the thickness of the second bonding layer is less than 10 nm.

[0165] Please refer to Fig.18After removing the sacrificial substrate 301 , a second electrode layer 307 is formed, the second electrode layer 307 is located on the second side 302 b , and the projections of the first electrode layer 303 and the second electrode layer 307 toward the substrate 300 have an overlapping area.

[0166] In this embodiment, the material of the second electrode layer 307 includes but is not limited to at least one of the following: molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0167] In this embodiment, a protection layer (not shown) is formed on the surface of the second electrode layer 307 to enhance the protection of the second electrode layer 307 .

[0168] Correspondingly, a bulk acoustic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Fig.18 , including: a substrate 300; an intermediate layer 308, located on the substrate 300, the intermediate layer 308 including a cavity 306 and a crystal defect, the crystal defect including: one or more of a point defect, a line defect and a surface defect; a piezoelectric layer 302, located on the intermediate layer 308, the piezoelectric layer 302 including a first side 302a and a second side 302b opposite to each other, the intermediate layer 308 and the substrate 300 are located on the first side 302a; a first electrode layer 303, located on the first side 302a of the piezoelectric layer 302; a second electrode layer 307, located on the second side 302b of the piezoelectric layer 302, and the projections of the first electrode layer 303 and the second electrode layer 307 toward the substrate 300 have an overlapping area.

[0169] By adding the intermediate layer 308 and the substrate 300 below the piezoelectric layer 302, the two will have a difference in acoustic impedance due to different materials, which can effectively prevent energy from leaking downward, thereby improving the Q value of the resonant device. Since the intermediate layer 308 and the substrate 300 are solid materials, their heat transfer coefficient is greater than the heat transfer coefficient of air, which can improve the heat dissipation of the resonant device, increase the power capacity of the resonant device, and improve the performance of the resonant device.

[0170] In addition, the crystal defects in the intermediate layer 308 can form charge traps, thereby preventing the formation of a conductive plane on the surface of the substrate 300, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0171] In this embodiment, the crystal defect is a point defect, and the point defect is a vacancy defect.

[0172] Please refer to Fig. 9 In this embodiment, the vacancy defect is a Frankel vacancy.

[0173] Please refer to Fig.10 In other embodiments, the vacancy defect may also be a Schottky vacancy.

[0174] In this embodiment, the intermediate layer 308 includes: a first bonding layer 3041 , a second bonding layer 305 , and the cavity 306 located in the first bonding layer 3041 , and the first bonding layer 3041 is bonded to the second bonding layer 305 .

[0175] In this embodiment, the second bonding layer 305 has the crystal defects therein.

[0176] The material of the first bonding layer 3041 includes silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound obtained by adding fluorine, carbon or boron to silicon dioxide, or any one of the materials having the above materials as main components.

[0177] The material of the second bonding layer 305 includes silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound obtained by adding fluorine, carbon or boron to silicon dioxide, or any one of materials having the above materials as main components.

[0178] It should be noted that since the first bonding layer 3041 and the second bonding layer 305 are both part of the intermediate layer 308, the corresponding material of the intermediate layer 308 also includes: silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound formed by adding fluorine, carbon or boron to silicon dioxide, or any one of the materials with the above materials as the main components.

[0179] In this embodiment, the material of the first bonding layer 3041 is silicon dioxide; the material of the second bonding layer 305 is silicon dioxide.

[0180] In this embodiment, the first bonding layer 3041 and the second bonding layer 305 are directly bonded using a silicon base.

[0181] In this embodiment, the crystal defect is located in a side of the second bonding layer 305 close to the substrate 300 .

[0182] In other embodiments, the bonding surface of the first bonding layer and the second bonding layer may further have the crystal defect.

[0183] In other embodiments, the crystal defects may be present in both the first bonding layer and the second bonding layer.

[0184] In other embodiments, the crystal defect may be present only in the first bonding layer, while the crystal defect may not be present in the second bonding layer. Preferably, the thickness of the second bonding layer is less than 10 nm.

[0185] In this embodiment, one end of the first electrode layer is located in the cavity 306 .

[0186] In other embodiments, both ends of the first electrode layer may be located in the cavity.

[0187] In this embodiment, the present invention further includes: a protection layer (not shown) located on the surface of the first electrode layer 303 to enhance the protection of the first electrode layer 303 .

[0188] In this embodiment, the present invention further includes: a protection layer (not shown) located on the surface of the second electrode layer 307 to enhance the protection of the second electrode layer 307 .

[0189] Fig.19 is a schematic diagram of defects of interstitial impurities in another embodiment of the present invention; Fig. 20 Schematic diagram of defects caused by substitutional impurities in another embodiment of the present invention.

[0190] In this embodiment, in the above embodiment ( Figure 8 and Fig.18 ) is further described on the basis of the method for forming a bulk acoustic wave resonator device, which is different from the above embodiment in that: the point defect is an impurity defect. The following will be specifically described in conjunction with the accompanying drawings.

[0191] Please refer to Fig.19 In this embodiment, the impurity defects are interstitial impurities.

[0192] Please refer to Fig. 20 In other embodiments, the impurity defects are substitutional impurities.

[0193] Correspondingly, a bulk acoustic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Fig.19 or Fig. 20 , the rest of the structure is the same as the BAW resonator described in the above embodiment, except that: the point defect is an impurity defect.

[0194] Please continue to refer to Fig.19 In this embodiment, the impurity defects are interstitial impurities.

[0195] Please continue to refer to Fig. 20 In other embodiments, the impurity defects are substitutional impurities.

[0196] Fig.21is a schematic diagram of an edge dislocation defect in another embodiment of the present invention; Fig. 22 Schematic diagram of a screw dislocation defect in another embodiment of the present invention.

[0197] In this embodiment, in the above embodiment ( Figure 8 and Fig.18 ), the method for forming a bulk acoustic wave resonator device is further described based on the above embodiment, which is different from the above embodiment in that: the crystal defect is a line defect, and the line defect is a dislocation defect. The following will be specifically described in conjunction with the accompanying drawings.

[0198] The formation of dislocation defects usually includes: due to the influence of temperature gradient, concentration gradient, mechanical vibration, etc., the growing crystal deflects or bends, causing phase differences between adjacent crystal blocks, and dislocations are formed between them; there are a large number of vacancies in the crystal, and the aggregation of vacancies can form dislocations; certain interfaces (such as second phase particles, twins, grain boundaries, etc.) and microcracks inside the crystal often have stress concentration due to the effects of thermal stress and structural stress, and dislocations are easily generated in this area. Dislocation defects can be formed using the process methods commonly used by those skilled in the art.

[0199] Please refer to Fig.21 In this embodiment, the dislocation defect is an edge dislocation.

[0200] Please refer to Fig. 22 In other embodiments, the dislocation defect is a screw dislocation.

[0201] Correspondingly, a bulk acoustic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Fig.21 or Fig. 22 , the rest of the structure is the same as the BAW resonator described in the above embodiment, except that: the crystal defect is a line defect, and the line defect is a dislocation defect.

[0202] Please continue to refer to Fig.21 In this embodiment, the dislocation defect is an edge dislocation.

[0203] Please continue to refer to Fig. 22 In other embodiments, the dislocation defect is a screw dislocation.

[0204] Fig.23 is a defect schematic diagram of a reconstructed atom in another embodiment of the present invention; Fig.24 It is a schematic diagram of defects on a relaxed surface in another embodiment of the present invention.

[0205] In this embodiment, in the above embodiment ( Figure 8 and Fig.18), the method for forming a bulk acoustic wave resonator device is further described based on the above embodiment, which is different from the above embodiment in that: the crystal defect is a surface defect, and the surface defect includes: a translation interface, a twin interface or a grain boundary. The following will be specifically described in conjunction with the accompanying drawings.

[0206] In this embodiment, the translation interface is a surface state defect.

[0207] Please refer to Fig.23 In this embodiment, the surface state defect is a reconstructed atom. Reconstructed atoms refer to the periodicity of the surface atomic layer in the horizontal direction being different from that of the atoms in the body, that is, the horizontal spacing between the surface atoms is d1, which is different from the horizontal spacing between the atoms in the body is d2, but the interlayer spacing in the vertical direction is the same as that of the atoms in the body. Reconstructed atomic defects can be formed by roughening (grinding, polishing), heat treatment or homoepitaxial growth, etc., which are commonly used by those skilled in the art.

[0208] Please refer to Fig.24 In other embodiments, the surface state defect is a relaxed surface. A relaxed surface refers to a phenomenon in which the vertical distance d3 between the surface layers is expanded and compressed compared to the vertical distance d4 between the surface and the atomic body, while the horizontal atomic distance is the same. Relaxed surface defects can be formed by annealing, mechanical deformation caused by applying stress, or growth process, etc., which are commonly used by those skilled in the art.

[0209] Correspondingly, a bulk acoustic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Fig.23 or Fig.24 , the rest of the structure is the same as the BAW resonator described in the above embodiment, except that: the crystal defect is a surface defect, and the surface defect includes: a translation interface, a twin interface or a grain boundary.

[0210] In this embodiment, the translation interface is a surface state defect.

[0211] Please refer to Fig.23 In this embodiment, the surface state defects are reconstructed atoms. Reconstructed atoms refer to the periodicity of the surface atomic layer in the horizontal direction being different from that of the atoms in the body, that is, the horizontal spacing between the surface atoms is d1, which is different from the horizontal spacing between the atoms in the body is d2, but the interlayer spacing in the vertical direction is the same as that of the atoms in the body.

[0212] Please refer to Fig.24 In other embodiments, the surface state defect is a relaxed surface. A relaxed surface refers to a phenomenon in which the vertical distance d3 between surface layers is expanded and compressed compared to the vertical distance d4 between the surface and the atomic body, while the horizontal atomic distance is the same.

[0213] Fig.25It is a schematic structural diagram of a bulk acoustic wave resonance device in another embodiment of the present invention.

[0214] Please refer to Fig.25 A bulk acoustic wave resonance device comprises: a substrate 400; an intermediate layer 401, located on the substrate 400, the intermediate layer 401 comprising a cavity 4011 and a crystal defect, the crystal defect comprising: one or more of a point defect, a line defect and a surface defect; a piezoelectric layer 402, located on the intermediate layer 401, the piezoelectric layer 402 comprising a first side 402a and a second side 402b opposite to each other, the intermediate layer 401 and the substrate 400 being located on the first side 402a; a first electrode layer 403, located on the first side 402a of the piezoelectric layer 402, the first electrode layer 403 being located on the intermediate layer 401 and covering the cavity 4011; a second electrode layer 404, located on the second side 402b of the piezoelectric layer 402, the projections of the first electrode layer 403 and the second electrode layer 404 towards the substrate 400 having an overlapping area.

[0215] It should be noted that, in this embodiment, the BAW resonator is formed in a stacking manner, and the corresponding piezoelectric layer 402 and the second electrode layer 404 have raised portions.

[0216] In this embodiment, the cavity 4011 and the crystal defect are located on opposite sides of the intermediate layer 401 , the cavity 4011 is located between the crystal defect and the piezoelectric layer 402 , and the crystal defect is located between the cavity 4011 and the substrate 400 .

[0217] In this embodiment, the crystal defect is located in a side of the intermediate layer 401 close to the substrate 400. Specifically, the intermediate layer 401 includes a first part 405 located between the cavity 4011 and the substrate 400, and a second part 406 located between the first part 405 and the piezoelectric layer 402. The crystal defect is located in a side of the first part 405 close to the substrate 400.

[0218] In this embodiment, the crystal defect can be any of the above embodiments ( Figure 8 , Figure 18 to Figure 24 ) are the same and will not be described again here.

[0219] Fig.26 It is a schematic structural diagram of a bulk acoustic wave resonance device in another embodiment of the present invention.

[0220] Please refer to Fig.26, a bulk acoustic wave resonance device, comprising: a substrate 500; an intermediate layer 501, located on the substrate 500, the intermediate layer 501 comprising a cavity 5011 and a crystal defect, the crystal defect comprising: one or more of a point defect, a line defect and a surface defect; an isolation layer 505, the isolation layer 505 being located between the substrate 500 and the intermediate layer 501; a piezoelectric layer 502, located on the intermediate layer 501, the piezoelectric layer 502 comprising a first side 502a and a second side 502b opposite to each other, the intermediate layer 501, the isolation layer 505 and the substrate 500 being located on the first side 502a; a first electrode layer 503, located on the first side 502a of the piezoelectric layer 502; a second electrode layer 504, located on the second side 502b of the piezoelectric layer 502, the projections of the first electrode layer 503 and the second electrode layer 504 toward the substrate 500 having an overlapping area.

[0221] The material of the isolation layer 505 includes, but is not limited to, one of the following: silicon dioxide, silicon nitride, silicon carbide or an amorphous insulating material.

[0222] In this embodiment, the isolation layer 505 is made of silicon dioxide.

[0223] In this embodiment, the thickness of the isolation layer 505 is less than 2 nm, or is between 20 nm and 20 um.

[0224] In this embodiment, the isolation layer 505 is first formed on the substrate 500 , and then the isolation layer 505 is bonded to the intermediate layer 501 .

[0225] In other embodiments, the isolation layer may be formed on the intermediate layer, and then the isolation layer is bonded to the substrate.

[0226] By forming the isolation layer 505 between the substrate 500 and the intermediate layer 501, the isolation layer 505 can block the heat transferred from the substrate 500 in the subsequent heat treatment process, thereby preventing the crystal defects in the intermediate layer 501 from being repaired due to heat, thereby causing the performance of the intermediate layer 501 to capture charges to decrease, thereby ensuring the capture performance of the intermediate layer 501 and improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0227] In this embodiment, the specific structure of the intermediate layer 501 and the distribution of the crystal defects can be the same as any of the above embodiments ( Figure 8 , Figure 18 to Figure 24 ) are the same and will not be described again here.

[0228] In this embodiment, one end of the first electrode layer 503 is located in the cavity 5011 .

[0229] In other embodiments, both ends of the first electrode layer may be located in the cavity, or the first electrode layer may be located on the middle layer.

[0230] Correspondingly, an embodiment of the present invention further provides a filter, comprising: a bulk acoustic wave resonance device as described in any one of the above embodiments.

[0231] 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: substrate; An intermediate layer, located on the substrate, the intermediate layer comprising cavities and crystal defects, wherein the crystal defects comprise: one or more of point defects, line defects and surface defects; a piezoelectric layer disposed on the intermediate layer, the piezoelectric layer comprising a first side and a second side opposite to each other, the intermediate layer and the substrate being disposed on the first side; A first electrode layer, located on a first side of the piezoelectric layer; The second electrode layer is located on the second side of the piezoelectric layer, and projections of the first electrode layer and the second electrode layer toward the substrate have an overlapping area.

2. The bulk acoustic wave resonator device according to claim 1, characterized in that: At least one end of the first electrode layer is located in the cavity.

3. The bulk acoustic wave resonator device according to claim 1, characterized in that: The first electrode layer is located on the middle layer, and the first electrode layer covers the cavity.

4. The bulk acoustic wave resonator device according to claim 1, characterized in that: The cavity and the crystal defect are located on opposite sides of the intermediate layer, the cavity is located between the crystal defect and the piezoelectric layer, and the crystal defect is located between the cavity and the substrate.

5. The bulk acoustic wave resonator device according to claim 4, characterized in that: The intermediate layer includes a first portion located between the cavity and the substrate, and a second portion located between the first portion and the piezoelectric layer, and the crystal defect is located in a side of the first portion close to the substrate.

6. The bulk acoustic wave resonator device according to claim 1, characterized in that: The point defects include: vacancy defects or impurity defects.

7. The bulk acoustic wave resonator device according to claim 6, characterized in that: The vacancy defects include Frankel vacancies or Schottky vacancies.

8. The bulk acoustic wave resonator device according to claim 6, characterized in that: The impurity defects include interstitial impurities or substitutional impurities.

9. The bulk acoustic wave resonator device according to claim 1, characterized in that: The line defects include: dislocation defects.

10. The bulk acoustic wave resonator device according to claim 9, characterized in that: The dislocation defect includes edge dislocation or screw dislocation.

11. The bulk acoustic wave resonator device according to claim 1, characterized in that: The surface defects include: translational interfaces, twin interfaces or grain boundaries.

12. The bulk acoustic wave resonator device according to claim 11, characterized in that: The translation interface includes: surface state defects.

13. The bulk acoustic wave resonator device according to claim 12, characterized in that: The surface state defects include: reconstructed atoms or relaxed surfaces.

14. The bulk acoustic wave resonator device according to claim 1, characterized in that: The material of the intermediate layer includes silicon dioxide, glass, silicon oxynitride, tantalum oxide, silicon nitride, titanium oxide, or a compound obtained by adding fluorine, carbon or boron to silicon dioxide, or any one of materials having the above materials as main components.

15. A method for forming a bulk acoustic wave resonator, characterized in that: include: providing a substrate; forming a piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite each other, the substrate being located on the first side; forming a first electrode layer, wherein the first electrode layer is located on the first side; forming an intermediate layer located between the substrate and the piezoelectric layer, the intermediate layer comprising cavities and crystal defects, the intermediate layer being located on the first side, the crystal defects comprising: one or more of point defects, line defects and surface defects; A second electrode layer is formed, where the second electrode layer is located on the second side, and projections of the first electrode layer and the second electrode layer toward the substrate have an overlapping area.

16. The method for forming a bulk acoustic wave resonator device according to claim 15, wherein: The method for forming the intermediate layer includes: forming a cavity pretreatment layer on the piezoelectric layer, the cavity pretreatment layer is used to form the cavity, the cavity pretreatment layer covers the first electrode layer, the cavity pretreatment layer is located on the first side, and forming the cavity pretreatment layer includes forming a sacrificial layer and a first bonding layer, the sacrificial layer at least covers a portion of the first electrode layer, and the first bonding layer at least covers the sacrificial layer.

17. The method for forming a bulk acoustic wave resonator device according to claim 16, wherein: The method of forming the first bonding layer includes forming the crystal defect in the first bonding layer.

18. The method for forming a bulk acoustic wave resonator device according to claim 17, wherein: The crystal defect and the sacrificial layer are located on two opposite sides of the first bonding layer, and the sacrificial layer is located between the crystal defect and the piezoelectric layer.

19. The method for forming a bulk acoustic wave resonator device according to claim 16, wherein: The method of forming the intermediate layer further includes bonding the cavity pretreatment layer and the substrate.

20. The method for forming a bulk acoustic wave resonator device according to claim 19, wherein: Bonding the cavity pretreatment layer and the substrate includes bonding the first bonding layer and the substrate, bonding surfaces of the first bonding layer and the substrate having the crystal defects.

21. The method for forming a bulk acoustic wave resonator device according to claim 16, wherein: The method of forming the intermediate layer further includes: forming a second bonding layer on the substrate; and bonding the cavity pretreatment layer and the second bonding layer.

22. The method for forming a bulk acoustic wave resonator device according to claim 21, wherein: Bonding the cavity pretreatment layer and the second bonding layer includes bonding the first bonding layer and the second bonding layer, wherein the first bonding layer and the second bonding layer are made of the same material.

23. The method for forming a bulk acoustic wave resonator device according to claim 21, wherein: A bonding surface of the cavity pretreatment layer and the second bonding layer has the crystal defect.

24. The method for forming a bulk acoustic wave resonator device according to claim 21, wherein: The method of forming the second bonding layer includes forming the crystal defects in the second bonding layer.

25. The method for forming a bulk acoustic wave resonator device according to claim 16, wherein: The method of forming the intermediate layer further includes: removing the sacrificial layer to form the cavity.

26. A filter, characterized in that: include: A bulk acoustic wave resonator device as claimed in any one of claims 1 to 14.

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