Bulk acoustic wave resonance device

Abstract

A bulk acoustic wave resonance device includes: an acoustic reflection layer; the first electrode layer comprises a first resonance part and a first extension part; a piezoelectric layer; the second electrode layer comprises a second resonance part and a second extension part; a dielectric layer, wherein a first dielectric part of the dielectric layer is located between a part of the first extension part and the piezoelectric layer; the load layer corresponds to the second extension part; the first attenuation area is used for attenuating sound waves; and the first limiting area is used for reflecting sound waves. The first-order transverse mode can pass through the first attenuation area without being affected, and then is fully reflected back to the resonance area in the first limiting area, so that transverse leaky waves are reduced; the high-order lateral parasitic mode entering the first attenuation region is attenuated, and only a small number or even no high-order lateral parasitic mode enters the first confinement region, so that the parallel impedance value and the corresponding Q value can be improved.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor technology, and in particular to a bulk acoustic wave resonator. Background Technology

[0002] Radio frequency (RF) front-end chips in wireless communication devices include power amplifiers, antenna switches, RF filters, multiplexers (including duplexers), and low-noise amplifiers. Among these, RF filters include surface acoustic wave (SAW) filters, bulk acoustic wave (BAW) filters, micro-electro-mechanical system (MEMS) filters, and integrated passive device (IPD) filters.

[0003] Bulk acoustic wave (BAW) resonators have a high quality factor (Q value). Low insertion loss and high out-of-band rejection radio frequency (RF) filters made from BAW resonators, known as BAW filters, are among the mainstream RF filters used in mobile phones, base stations, and other wireless communication devices. The Q value is the quality factor of the resonator, defined as the center frequency divided by the resonator's 3dB bandwidth. BAW filters are typically used in frequencies ranging from 0.7GHz to 7GHz.

[0004] As wireless communication technology evolves, the number of frequency bands used increases. Simultaneously, with the application of technologies such as carrier aggregation and frequency band overlay, mutual interference between wireless frequency bands becomes increasingly severe. High-performance bulk acoustic wave 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, and currently only bulk acoustic wave technology can solve the filtering problem of high-frequency bands.

[0005] However, bulk acoustic resonator devices still have many problems. Utility Model Content

[0006] The technical problem solved by this utility model is to provide a bulk acoustic resonator to improve the Q of the acoustic resonator.

[0007] To address the aforementioned problems, this utility model provides a bulk acoustic resonator, comprising: an acoustic reflection layer; a first electrode layer, the first electrode layer including a first resonant portion and a first extension portion located outside the first resonant portion, the first extension portion surrounding the first resonant portion; a piezoelectric layer including a first side and a second side opposite to the first side, the first electrode layer being located on the first side, and the acoustic reflection layer being located on either the first side or the second side; a second electrode layer, the second electrode layer being located on the second side, the second electrode layer including a second resonant portion and a second extension portion located outside the second resonant portion, the second extension portion surrounding the second resonant portion, the second resonant portion corresponding to the first resonant portion; and a resonant region, the resonant region including... The system comprises: a first resonant region, a second resonant region, and a piezoelectric layer located between the first resonant region and the second resonant region; a dielectric layer located on the first side, the dielectric layer including a first dielectric portion located between the first extension and the piezoelectric layer; a load layer located on the second side, the load layer corresponding to the second extension; a first attenuation region located outside the resonant region for attenuating sound waves, the first attenuation region surrounding the resonant region, the first attenuation region including the first extension and the first dielectric portion; and a first confinement region located outside the first attenuation region for reflecting sound waves, the first confinement region surrounding the first attenuation region, the first confinement region including the second extension and the load layer.

[0008] Optionally, the angle between the first extension and the first resonant portion is greater than or equal to 90° and less than 180°.

[0009] Optionally, the thickness range of the dielectric layer includes 0.1T1 to 10T1, where T1 represents the thickness of the first electrode layer; the width range of the first dielectric portion includes 0.1T to 10T, where T represents the thickness of the resonant region stacked structure.

[0010] Optionally, the thickness of the load layer ranges from 0.1T2 to 10T2, where T2 represents the thickness of the second electrode layer; the width of the load layer ranges from 0.1T to 10T, where T represents the thickness of the resonant region stacked structure.

[0011] Optionally, the load layer is located between the piezoelectric layer and the second extension.

[0012] Optionally, the second extension is located between the piezoelectric layer and the load layer.

[0013] Optionally, the spacing between the outer edge of the second electrode layer and the outer edge of the load layer ranges from -10T to 10T, where T represents the thickness of the resonant region stacked structure.

[0014] Optionally, the first electrode layer further includes: a third extension located outside the first extension, the third extension surrounding the first extension, and a second extension corresponding to the third extension; the dielectric layer further includes: a second dielectric portion located between the third extension and the piezoelectric layer; the first confinement region further includes: the third extension and the second dielectric portion.

[0015] Optionally, the second electrode layer further includes: a fourth extension located outside the second resonant portion, the fourth extension surrounding the second resonant portion, the second extension surrounding the fourth extension, and the fourth extension corresponding to the first extension; the first attenuation region further includes: the fourth extension.

[0016] Optionally, the first electrode layer further includes a fifth extension located outside the first extension, the fifth extension surrounding the first extension; the dielectric layer further includes a third dielectric portion located between the piezoelectric layer and the fifth extension.

[0017] Optionally, it further includes: a second attenuation region located outside the first restriction region for attenuating sound waves, the second attenuation region surrounding the first restriction region, the second attenuation region including the fifth extension and the third dielectric portion.

[0018] Optionally, the second electrode layer further includes: a sixth extension located outside the second extension, the sixth extension surrounding the second extension, the sixth extension corresponding to the fifth extension, and the second attenuation region further including the sixth extension.

[0019] Optionally, the acoustic reflective layer may include a cavity or a Bragg reflective layer.

[0020] Optionally, the acoustic reflection layer is a Bragg reflection layer, the Bragg reflection layer is located on the first side, and the first electrode layer and the dielectric layer are located between the Bragg reflection layer and the piezoelectric layer.

[0021] Optionally, the acoustic reflection layer is a Bragg reflection layer, which is located on the second side, and the second electrode layer and the load layer are located between the Bragg reflection layer and the piezoelectric layer.

[0022] Optionally, the acoustic reflection layer is a cavity located on the first side, the first electrode layer and the dielectric layer are located between the cavity and the piezoelectric layer, and the first electrode layer covers the cavity.

[0023] Optionally, the acoustic reflection layer is a cavity located on the first side, and the first electrode layer and the dielectric layer are located inside the cavity.

[0024] Optionally, the acoustic reflection layer is a cavity located on the second side, the second electrode layer and at least a portion of the load layer are located between the cavity and the piezoelectric layer, and the second electrode layer covers the cavity.

[0025] Optionally, the acoustic reflection layer is a cavity located on the second side, and the second electrode layer and the load layer are located inside the cavity.

[0026] Compared with the prior art, the technical solution of this utility model has the following advantages:

[0027] In the bulk acoustic resonator of this invention, the dielectric layer of the first attenuation region and the load layer of the first confinement region are located on opposite sides of the piezoelectric layer. Since the acoustic impedance of the first attenuation region is matched (e.g., equal to or less than) that of the resonant region, while the acoustic impedance of the first confinement region is mismatched with that of the first attenuation region (i.e., the impedance difference is large), the first-order transverse mode can pass through the first attenuation region unaffected and then be fully reflected back to the resonant region in the first confinement region, thereby significantly reducing transverse leakage. However, higher-order transverse parasitic modes entering the first attenuation region will experience attenuation. By reasonably setting the width of the first attenuation region, the higher-order transverse parasitic modes can be fully attenuated within the first attenuation region, with only a small number or even no higher-order transverse parasitic modes entering the first confinement region, thereby preventing the higher-order transverse parasitic modes from reflecting back to the resonant region and coupling with the first-order transverse mode. This can improve the parallel impedance value and the corresponding Q value. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a bulk acoustic resonator;

[0029] Figure 2 This is a schematic diagram of the structure of a bulk acoustic resonator device in one embodiment of this utility model;

[0030] Figure 3 This is a comparison chart of the real part amplitude of impedance and the quality factor as a function of frequency between the present invention and existing technologies;

[0031] Figure 4 This is a schematic diagram of the structure of a bulk acoustic resonator device in another embodiment of this utility model;

[0032] Figure 5 This is a schematic diagram of the structure of a bulk acoustic resonator device in another embodiment of this utility model;

[0033] Figure 6 This is a schematic diagram of the structure of a bulk acoustic resonator device in another embodiment of this utility model;

[0034] Figure 7 This is a schematic diagram of the structure of a bulk acoustic resonator device in another embodiment of this utility model;

[0035] Figure 8 This is a schematic diagram of the structure of a bulk acoustic resonator device in another embodiment of this utility model;

[0036] Figure 9 This is a schematic diagram of the structure of a bulk acoustic resonator device in another embodiment of this utility model;

[0037] Figure 10 This is a schematic diagram of the structure of a bulk acoustic resonator device in another embodiment of this utility model;

[0038] Figure 11 This is a schematic diagram of the structure of a bulk acoustic resonator device in another embodiment of this utility model;

[0039] Figure 12 This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention. Detailed Implementation

[0040] As described in the background section, bulk acoustic resonator devices still have many problems. These will be explained in detail below with reference to the accompanying drawings.

[0041] Figure 1 This is a schematic diagram of a bulk acoustic resonator.

[0042] Please refer to Figure 1A bulk acoustic resonant device includes: a substrate 100 having a cavity 101 within it, with the cavity 101 exposed on the surface of the substrate 100; a lower electrode layer 102 on the substrate 100, covering the cavity 101; a piezoelectric layer 103 on the lower electrode layer 102; an upper electrode layer 104 on the piezoelectric layer 103, the projections of the upper electrode layer 104 and the lower electrode layer 102 toward the substrate 100 having an overlapping region, the overlapping region constituting a resonant region I; a raised edge structure 105 on the piezoelectric layer 103 surrounding the upper electrode layer 104; and a reflection region II located laterally outside the resonant region I, surrounding the resonant region I, the reflection region II including the raised edge structure 105, the acoustic impedance of the reflection region II being mismatched with the acoustic impedance of the resonant region I, i.e., a large difference in acoustic impedance.

[0043] There are two main factors that reduce the quality factor at the parallel resonant point of the bulk acoustic resonator: (1) the sound wave propagates laterally from the resonant region I to the region outside the resonant region I, causing acoustic energy leakage; (2) the higher-order transverse parasitic mode is coupled with the first-order transverse mode.

[0044] In the above embodiment, the reflection zone II formed by the protruding edge structure 105 on the lateral outer side of the resonant zone I can suppress the influence caused by the first factor and reflect the first-order lateral mode back to the resonant zone I, preventing most of the sound energy leakage. However, it cannot improve the second influencing factor. The protruding edge structure 105 reflects the first-order lateral mode while also reflecting the higher-order lateral parasitic mode.

[0045] Based on this, the present invention provides a bulk acoustic resonator device in which the first-order transverse mode can pass through the first attenuation region unaffected, and then be fully reflected back to the resonant region in the first restriction region, thereby significantly reducing transverse leakage. Higher-order transverse parasitic modes entering the first attenuation region will undergo attenuation, which can ensure that the higher-order transverse parasitic modes are fully attenuated in the first attenuation region, with only a small number or even no higher-order transverse parasitic modes entering the first restriction region, thereby preventing the higher-order transverse parasitic modes from reflecting back to the resonant region and coupling with the first-order transverse mode. This can improve the parallel impedance value and the corresponding Q value.

[0046] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0047] Figure 2 This is a schematic diagram of the structure of a bulk acoustic resonator device in one embodiment of this utility model; Figure 3This is a comparison chart of the real part amplitude of impedance and the quality factor as a function of frequency between the present invention and existing technologies.

[0048] Please refer to Figure 2 A bulk acoustic resonant device includes: an acoustic reflection layer; a first electrode layer 201, the first electrode layer 201 including a first resonant portion 2011 and a first extension portion 2012 located outside the first resonant portion 2011, the first extension portion 2012 surrounding the first resonant portion 2011; a piezoelectric layer 202, the piezoelectric layer 202 including a first side 202a and a second side 202b opposite to the first side 202a, the first electrode layer 201 located on the first side 202a, and the acoustic reflection layer located on either the first side 202a or the second side 202b; a second electrode layer 203, the second electrode layer 203 located on the second side 202b, the second electrode layer 203 including a second resonant portion 2031 and a second extension portion 2033 located outside the second resonant portion 2031, the second extension portion 2033 surrounding the second resonant portion 2031, the second resonant portion 2031 corresponding to the first resonant portion 2011; and a resonant region I, the resonant region I including the first resonant portion 2011. 011, the second resonant portion 2031, and the piezoelectric layer 202 located between the first resonant portion 2011 and the second resonant portion 2031; a dielectric layer 204 located on the first side 202a, the dielectric layer 204 including a first dielectric portion 2041 located between the first extension portion 2012 and the piezoelectric layer 202; a load layer 205 located on the second side 202b, the load layer 205 corresponding to the second extension portion 2033; a first attenuation region II located outside the resonant region I for attenuating sound waves, the first attenuation region II surrounding the resonant region I, the first attenuation region II including the first extension portion 2012 and the first dielectric portion 2041; a first confinement region III located outside the first attenuation region II for reflecting sound waves, the first confinement region III surrounding the first attenuation region II, the first confinement region III including the second extension portion 2033 and the load layer 205.

[0049] The dielectric layer 204 of the first attenuation region II and the load layer 205 of the first confinement region III are located on opposite sides of the piezoelectric layer 202. Since the acoustic impedance of the first attenuation region II is matched (e.g., equal to or less than) the acoustic impedance of the resonant region I, while the acoustic impedance of the first confinement region III is mismatched with that of the first attenuation region II, i.e., the impedance difference is large, the first-order transverse mode can pass through the first attenuation region II unaffected, and then be fully reflected back to the resonant region I in the first confinement region III, thereby significantly reducing transverse leakage. However, the higher-order transverse parasitic modes entering the first attenuation region II will undergo attenuation. By reasonably setting the width of the first attenuation region II, the higher-order transverse parasitic modes can be fully attenuated in the first attenuation region II, with only a small number or even no higher-order transverse parasitic modes entering the first confinement region III, thereby preventing the higher-order transverse parasitic modes from being reflected back to the resonant region I and coupling with the first-order transverse mode. This can improve the parallel impedance value and the corresponding Q value.

[0050] Please refer to Figure 3 In the figure, the horizontal axis represents frequency, the left vertical axis represents the amplitude of the real part of the impedance, and the right vertical axis represents the quality factor (BodeQ) as a function of frequency. The solid triangular line in the figure represents the amplitude of the real part of the impedance in the bulk acoustic wave resonator of this invention, while the dashed triangular line represents the amplitude of the real part of the impedance in a prior art bulk acoustic wave resonator. The frequency corresponding to the highest point represents the parallel resonant frequency of the resonator. The solid line in the figure represents the BodeQ curve of the bulk acoustic wave resonator of this invention, and the dashed line represents the BodeQ curve of a prior art bulk acoustic wave resonator. The point with the maximum vertical value is the Qmax value. The BodeQ of the bulk acoustic wave resonator corresponding to the parallel resonant frequency is the parallel resonant Q value of the bulk acoustic wave resonator. It can be seen from the figure that the Qmax value and parallel resonant Q value of the bulk acoustic wave resonator provided by this embodiment are significantly better than those of the prior art.

[0051] In this embodiment, the first electrode layer 201 further includes a third extension 2013 located outside the first extension 2012, the third extension 2013 surrounding the first extension 2012, and the second extension 2033 corresponding to the third extension 2013; the dielectric layer 204 further includes a second dielectric portion 2042 located between the third extension 2013 and the piezoelectric layer 202; the first confinement region III further includes the third extension 2013 and the second dielectric portion 2042.

[0052] In this embodiment, the second electrode layer 203 further includes: a fourth extension 2032 located outside the second resonant portion 2031, the fourth extension 2032 surrounding the second resonant portion 2031, the second extension 2033 surrounding the fourth extension 2032, the fourth extension 2032 corresponding to the first extension 2012; the first attenuation region II further includes: the fourth extension 2032.

[0053] In this embodiment, the material of the first electrode layer 201 includes, but is not limited to, one of the following: molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold, or hafnium.

[0054] In this embodiment, the material of the second electrode layer 203 includes, but is not limited to, one of the following: molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold, or hafnium.

[0055] In this embodiment, the material of the piezoelectric layer 202 includes, but is not limited to, one of the following: lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate, aluminum nitride, aluminum nitride alloy, gallium nitride, or zinc oxide.

[0056] In this embodiment, the material of the dielectric layer 204 includes, but is not limited to, one of the following: silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, or air.

[0057] In this embodiment, the material of the load layer 205 includes, but is not limited to, one of the following: molybdenum, tungsten, platinum, palladium, gold, chromium, tantalum, or iridium.

[0058] In this embodiment, the first dielectric portion 2041 is located between the first extension portion 2012 and the piezoelectric layer 202, and the second dielectric portion 2042 is located between the third extension portion 2013 and the piezoelectric layer 202.

[0059] Please continue to refer to this. Figure 2 In this embodiment, the included angle between the first extension 2012 and the first resonant part 2011 is equal to 90°.

[0060] In other embodiments, the angle between the first extension and the first resonant portion may be greater than 90° and less than 180°.

[0061] In this embodiment, the thickness of the dielectric layer 204 ranges from 0.1T1 to 10T1, where T1 represents the thickness of the first electrode layer 201; the width of the first dielectric portion 2041 ranges from 0.1T to 10T, where T represents the thickness of the resonant region I stacked structure (for example, the sum of the thicknesses of the first resonant portion 2011, the second resonant portion 2031, and the piezoelectric layer 202).

[0062] In this embodiment, the thickness of the load layer 205 ranges from 0.1T2 to 10T2, where T2 represents the thickness of the second electrode layer 203; the width of the load layer 205 ranges from 0.1T to 10T, where T represents the thickness of the resonant region I stacked structure.

[0063] In this embodiment, the material density of the load layer 205 is greater than or equal to the material density of the second electrode layer 203, which is used to increase the overall mass of the first confinement region III, thereby increasing the difference between the acoustic impedance of the first confinement region III and the acoustic impedance of the resonant region I, thus forming an acoustic impedance mismatch.

[0064] In other embodiments, the material density of the load layer may be less than that of the second electrode layer, such as using aluminum as the material of the load layer.

[0065] Please continue to refer to this. Figure 2 In this embodiment, the load layer 205 is located between the piezoelectric layer 202 and the second extension 2033.

[0066] In other embodiments, the second extension may also be located between the piezoelectric layer and the load layer.

[0067] The spacing between the outer edge of the second electrode layer 203 and the outer edge of the load layer 205 ranges from -10T to 10T, where T represents the thickness of the resonant region I stacked structure. A negative spacing indicates that the outer edge of the second electrode layer 203 is located inside the outer edge of the load layer 205 (i.e., the load layer 205 is not covered by the second electrode layer 203); a positive spacing indicates that the outer edge of the second electrode layer 203 is located outside the outer edge of the load layer 205 (i.e., the load layer 205 is covered by the first electrode layer 201).

[0068] Please continue to refer to this. Figure 2 In this embodiment, the distance between the outer edge of the first electrode layer 201 and the outer edge of the load layer 205 is 0 (i.e., flush).

[0069] In this embodiment, it also includes: a substrate 200, and a cavity 2001 located within the substrate 200, the surface of the substrate 200 exposing the cavity 2001.

[0070] In this embodiment, the acoustic reflection layer includes the cavity 2001, the cavity 2001 is located on the first side 202a, the first electrode layer 201 and the dielectric layer 204 are located between the cavity 2001 and the piezoelectric layer 202, and the first electrode layer 201 covers the cavity 2001.

[0071] Figure 4 This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention.

[0072] Please refer to Figure 4 This embodiment is based on the above embodiment ( Figure 2 Based on the above embodiments, the description of the bulk acoustic resonator device continues. The rest is the same as the above embodiments, except that the angle between the first extension 2012 and the first resonator 2011 is greater than 90° and less than 180°.

[0073] Figure 5 This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention.

[0074] Please refer to Figure 5 This embodiment is based on the above embodiment ( Figure 2 Based on the above embodiments, the description of the bulk acoustic resonator device continues. The rest is the same as the above embodiments, except that the second extension 2033 is located between the piezoelectric layer 202 and the load layer 205.

[0075] Figure 6 This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention.

[0076] This embodiment is based on the above embodiment ( Figure 2 Based on the above embodiments, the description of the bulk acoustic resonator will continue. The rest is the same as the previous embodiments, except that it also includes a second attenuation region. The following will describe this in detail with reference to the accompanying drawings.

[0077] Please refer to Figure 6 The first electrode layer 201 further includes a fifth extension 2014 located outside the third extension 2013, the fifth extension 2014 surrounding the third extension 2013; the dielectric layer 204 further includes a third dielectric portion 2043 located between the piezoelectric layer 202 and the fifth extension 2014; the second electrode layer 203 further includes a sixth extension 2034 located outside the second extension 2033, the sixth extension 2034 surrounding the second extension 2033, the sixth extension 2034 corresponding to the fifth extension 2014.

[0078] Please continue to refer to this. Figure 6 In this embodiment, the bulk acoustic resonator further includes a second attenuation region IV located outside the first restriction region III for attenuating sound waves. The second attenuation region IV surrounds the first restriction region III and includes the fifth extension 2014, the sixth extension 2034, and the third dielectric portion 2043.

[0079] It should be noted that, in addition to the features described in the above embodiments (such as...), the bulk acoustic resonator also includes... Figure 2 The first attenuation region II and the first restriction region III described in the figure can be flexibly configured according to the actual application scenario. However, it should be noted that the attenuation region and the restriction region need to be arranged alternately, and the region adjacent to the resonant region I needs to be the attenuation region (i.e., the first attenuation region II).

[0080] In this embodiment, two attenuation regions and one restriction region are configured, namely the first attenuation region II and the second attenuation region IV, and the first restriction region III located between the first attenuation region II and the second attenuation region IV.

[0081] Figure 7 This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention.

[0082] Please refer to Figure 7 This embodiment is based on the above embodiment ( Figure 2 Based on the above embodiments, the bulk acoustic resonator device will continue to be described. The rest is the same as the above embodiments, except that the cavity 2001 is located on the first side 202a, and the first electrode layer 201 and the dielectric layer 204 are located inside the cavity 2001.

[0083] In other embodiments, the bulk acoustic resonator may further include the second attenuation region (see details). Figure 6 As described in the relevant descriptions, which will not be repeated here, the second electrode layer covers the load layer.

[0084] Figure 8 This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention.

[0085] This embodiment is based on the above embodiment ( Figure 2 Based on the above embodiments, the bulk acoustic resonator will continue to be described. The rest is the same as the previous embodiments, except that the acoustic reflection layer is a Bragg reflector layer 300, which is located on the first side 202a. The following will describe it in detail with reference to the accompanying drawings.

[0086] Please refer to Figure 8In this embodiment, the first electrode layer 201 and the dielectric layer 204 are located between the Bragg reflector layer 300 and the piezoelectric layer 202.

[0087] It should be noted that, in this embodiment, because the dielectric layer 204 is present between the first electrode layer 201 and the piezoelectric layer 202, the first electrode layer 201 will have a stepped shape. Therefore, in order to ensure that the first electrode layer 201 and the Bragg reflector layer 300 can be in close contact, the stepped morphology of the first electrode layer 201 needs to be processed to make the surface in contact with the Bragg reflector layer 300 flat.

[0088] In other embodiments, the bulk acoustic resonator may further include the second attenuation region (see details). Figure 6 As described in the relevant descriptions, which will not be repeated here, the second electrode layer covers the load layer.

[0089] Figure 9 This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention.

[0090] This embodiment is based on the above embodiment ( Figure 2 Based on the above embodiments, the description of the bulk acoustic resonator device will continue. The rest is the same as the previous embodiment, except that the acoustic reflection layer is a Bragg reflector layer 300, which is located on the second side 202b. The following will describe it in detail with reference to the accompanying drawings.

[0091] Please refer to Figure 9 In this embodiment, the second electrode layer 203 and the load layer 205 are located between the Bragg reflector layer 300 and the piezoelectric layer 202.

[0092] It should be noted that the Bragg reflector layer 300 can only be located on the second side 202b when the load layer 205 is located between the piezoelectric layer 202 and the second extension 2033. When the second extension 2033 is located between the piezoelectric layer 202 and the load layer 205, since the load layer 205 is convex and cannot be flattened, the Bragg reflector layer 300 can not be located on the second side 202b in this structure.

[0093] In this embodiment, because the load layer 205 is located between the second electrode layer 203 and the piezoelectric layer 202, the second electrode layer 203 will have a stepped shape. Therefore, in order to ensure that the second electrode layer 203 and the Bragg reflector layer 300 can be in close contact, the stepped morphology of the second electrode layer 203 needs to be processed to make the surface in contact with the Bragg reflector layer 300 flat.

[0094] In other embodiments, the bulk acoustic resonator may further include the second attenuation region (see details). Figure 6 As described in the relevant descriptions, which will not be repeated here, the second electrode layer covers the load layer.

[0095] Figure 10 This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention.

[0096] Please refer to Figure 10 This embodiment is based on the above embodiment ( Figure 2 Based on the above embodiments, the description of the bulk acoustic resonator device continues. The rest is the same as the above embodiments, except that: the cavity 2001 is located on the second side 202b, the second electrode layer 203 is located between the cavity 2001 and the piezoelectric layer 202, at least part of the load layer 205 is located between the cavity 2001 and the piezoelectric layer 202, and the second electrode layer 203 covers the cavity 2001.

[0097] In this embodiment, a portion of the load layer 205 is located between the cavity 2001 and the piezoelectric layer 202.

[0098] Figure 11 This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention.

[0099] Please refer to Figure 11 This embodiment is based on the above embodiment ( Figure 6 Based on the above embodiments, the description of the bulk acoustic resonator device continues. The rest is the same as the above embodiments, except that: the cavity 2001 is located on the second side 202b, the second electrode layer 203 is located between the cavity 2001 and the piezoelectric layer 202, at least part of the load layer 205 is located between the cavity 2001 and the piezoelectric layer 202, and the second electrode layer 203 covers the cavity 2001.

[0100] In this embodiment, the entire load layer 205 is located between the cavity 2001 and the piezoelectric layer 202.

[0101] Figure 12This is a schematic diagram of the structure of a bulk acoustic resonator in another embodiment of the present invention.

[0102] Please refer to Figure 12 This embodiment is based on the above embodiment ( Figure 2 Based on the above embodiments, the description of the bulk acoustic resonator device continues. The rest is the same as the above embodiments, except that the cavity 2001 is located on the second side 202b, and the second electrode layer 203 and the load layer 205 are located inside the cavity 2001.

[0103] In other embodiments, the bulk acoustic resonator may further include the second attenuation region (see details). Figure 6 As described in the relevant descriptions, which will not be repeated here, the second electrode layer covers the load layer.

[0104] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A bulk acoustic wave resonator device, characterized by, The first electrode layer includes a first resonance portion and a first extension portion outside the first resonance portion, the first extension portion surrounding the first resonance portion. The piezoelectric layer includes a first side and a second side opposite to the first side, the first electrode layer being on the first side, the sound reflection layer being on the first side or the second side. The second electrode layer includes a second resonance portion and a second extension portion outside the second resonance portion, the second extension portion surrounding the second resonance portion, the second resonance portion corresponding to the first resonance portion. The resonance region includes the first resonance portion, the second resonance portion, and the piezoelectric layer between the first resonance portion and the second resonance portion. The dielectric layer includes a first dielectric portion between the first extension portion and the piezoelectric layer. The load layer is on the second side, the load layer corresponding to the second extension portion. The first attenuation region outside the resonance region is for attenuating sound waves, the first attenuation region surrounding the resonance region, the first attenuation region including the first extension portion and the first dielectric portion. The first restriction region outside the first attenuation region is for reflecting sound waves, the first restriction region surrounding the first attenuation region, the first restriction region including the second extension portion and the load layer. An included angle between the first extension portion and the first resonance portion is greater than or equal to 90° and less than 180°. A thickness of the dielectric layer ranges from 0.1T1 to 10T1, where T1 represents a thickness of the first electrode layer, and a width of the first dielectric portion ranges from 0.1T to 10T, where T represents a thickness of a resonance region stacked structure.

2. The bulk acoustic wave resonator device of claim 1, wherein, A thickness of the load layer ranges from 0.1T2 to 10T2, where T2 represents a thickness of the second electrode layer, and a width of the load layer ranges from 0.1T to 10T, where T represents the thickness of the resonance region stacked structure.

3. The bulk acoustic wave resonator device of claim 1, wherein, The load layer is between the piezoelectric layer and the second extension portion.

4. The bulk acoustic wave resonator device of claim 1, wherein, The second extension portion is between the piezoelectric layer and the load layer.

5. The bulk acoustic wave resonator device of claim 1, wherein, A spacing between an outer side edge of the second electrode layer and an outer side edge of the load layer ranges from -10T to 10T, where T represents the thickness of the resonance region stacked structure.

6. The bulk acoustic wave resonator device of claim 1, wherein, The first electrode layer further includes a third extension portion outside the first extension portion, the third extension portion surrounding the first extension portion, the second extension portion corresponding to the third extension portion, the dielectric layer further includes a second dielectric portion between the third extension portion and the piezoelectric layer, and the first restriction region further includes the third extension portion and the second dielectric portion.

7. The bulk acoustic wave resonator device of claim 1, wherein, ​ 8. The bulk acoustic wave resonator device of claim 1, wherein, ​ 9. The bulk acoustic wave resonator device of claim 1, wherein, The second electrode layer further comprises a fourth extending part outside the second resonant part, the fourth extending part surrounds the second resonant part, the second extending part surrounds the fourth extending part, and the fourth extending part corresponds to the first extending part; and the first attenuation area further comprises the fourth extending part.

10. The bulk acoustic wave resonator device of claim 1, wherein, The first electrode layer further comprises a fifth extending part outside the first extending part, the fifth extending part surrounds the first extending part; and the dielectric layer further comprises a third dielectric part between the piezoelectric layer and the fifth extending part.

11. The bulk acoustic wave resonator device of claim 10, wherein, Further comprising: a second attenuation area outside the first limiting area, for attenuating sound waves, the second attenuation area surrounds the first limiting area, and the second attenuation area comprises the fifth extending part and the third dielectric part.

12. The bulk acoustic wave resonator device of claim 11, wherein, The second electrode layer further comprises a sixth extending part outside the second extending part, the sixth extending part surrounds the second extending part, the sixth extending part corresponds to the fifth extending part, and the second attenuation area further comprises the sixth extending part.

13. The bulk acoustic wave resonator device of claim 1, wherein, The sound reflection layer comprises a cavity or a Bragg reflection layer.

14. The bulk acoustic wave resonator device of claim 13, wherein, The sound reflection layer is a Bragg reflection layer, the Bragg reflection layer is located on the first side, and the first electrode layer and the dielectric layer are located between the Bragg reflection layer and the piezoelectric layer.

15. The bulk acoustic wave resonator device of claim 13, wherein, The sound reflection layer is a Bragg reflection layer, the Bragg reflection layer is located on the second side, and the second electrode layer and the load layer are located between the Bragg reflection layer and the piezoelectric layer.

16. The bulk acoustic wave resonator device of claim 13, wherein, The sound reflection layer is a cavity, the cavity is located on the first side, the first electrode layer and the dielectric layer are located between the cavity and the piezoelectric layer, and the first electrode layer covers the cavity.

17. The bulk acoustic wave resonator device of claim 13, wherein, The sound reflection layer is a cavity, the cavity is located on the first side, and the first electrode layer and the dielectric layer are located in the cavity.

18. The bulk acoustic wave resonator device of claim 13, wherein, The sound reflection layer is a cavity, the cavity is located on the second side, the second electrode layer and at least part of the load layer are located between the cavity and the piezoelectric layer, and the second electrode layer covers the cavity.

19. The bulk acoustic wave resonator device of claim 13, wherein, The sound reflection layer is a cavity, the cavity is located on the second side, and the second electrode layer and the load layer are located in the cavity.

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