WO2023036024A1

WO2023036024A1 - Surface acoustic wave resonance device, filtering device, and radio frequency front end device

Info

Publication number: WO2023036024A1
Application number: PCT/CN2022/116062
Authority: WO
Inventors: 韩兴; 周建
Original assignee: 常州承芯半导体有限公司
Priority date: 2021-09-08
Filing date: 2022-08-31
Publication date: 2023-03-16
Also published as: CN113810007A; CN113810007B

Abstract

Embodiments of the present invention provide a surface acoustic wave resonance device, a filtering device, and a radio frequency front end device. The surface acoustic wave resonance device comprises: a support layer; a piezoelectric layer that is located above the support layer, the piezoelectric layer comprising a first side and a second side opposite to the first side, and the support layer being located on the first side; a reflective dielectric layer that is located on the first side, located above the support layer, and embedded in the piezoelectric layer; and an electrode layer that is located on the second side and located on the piezoelectric layer. The reflective dielectric layer comprises a first top portion and a first side portion; the first top portion comprises a first concave-convex portion, and the first side portion comprises a second concave-convex portion; and the roughness of the second concave-convex portion is greater than that of the first concave-convex portion. The reflective dielectric layer is located between the piezoelectric layer and the support layer and embedded in the piezoelectric layer, the reflective dielectric layer comprises an irregular concave-convex portion, and bulk acoustic waves generated by the electrode layer are irregularly reflected at the irregular concave-convex portion, such that the bulk acoustic waves reflected to the upper surface of the piezoelectric layer can be reduced, thereby reducing spurious resonance.

Description

Surface acoustic wave resonance device, filter device and radio frequency front-end device

This application claims the priority of the Chinese patent application with the application number 202111054657.2 and the title of the invention "Surface Acoustic Wave Resonator Device, Filter Device, and Radio Frequency Front-End Device" filed with the China Patent Office on September 8, 2021, the entire contents of which are incorporated by reference incorporated in this application.

technical field

The invention relates to the technical field of semiconductors, in particular, the invention relates to a surface acoustic wave resonator device, a filter device and a radio frequency front-end device.

Background technique

Radio Frequency (RF) front-end chips of wireless communication equipment include power amplifiers, antenna switches, RF filters, multiplexers, and low-noise amplifiers. Among them, radio frequency filters include piezoelectric surface acoustic wave (Surface Acoustic Wave, SAW) filter, piezoelectric bulk acoustic wave (Bulk Acoustic Wave, BAW) filter, micro-electro-mechanical system (Micro-Electro-Mechanical System, MEMS) filter , Integrated Passive Devices (IPD) filters, etc.

Figure 1 shows a SAW resonator 100, including: a substrate 110; a piezoelectric layer 130 located on the substrate 110, the piezoelectric layer 130 includes a first side 131 and a second side opposite to the first side 131 Two sides 133, the substrate 110 is located on the first side 131; and an electrode layer 150, located on the second side 133, is located on the piezoelectric layer 130, wherein the electrode layer 150 includes an interdigital transducer InterDigital Transducers (IDT), the IDT includes a plurality of electrode strips 151 and a plurality of electrode strips 153, the polarities of the plurality of electrode strips 151 and the plurality of electrode strips 153 are different, wherein the electrode strips 151 and the electrode strips 153 are alternately placed. It should be noted that, when a voltage is applied between the electrode strips 151 and the electrode strips 153, in addition to exciting the surface acoustic wave propagating parallel to the piezoelectric layer 130, a bulk acoustic wave (bulk acoustic wave) is also generated along the Propagate in a direction perpendicular to the piezoelectric layer 130 (that is, the direction corresponding to the thickness of the piezoelectric layer 130), as shown in FIG. Regular reflection occurs on the surface (that is, the reflection angles of the reflected waves are similar, so the reflection directions of the reflected waves are relatively uniform), and the reflected bulk acoustic wave is transmitted back to the surface of the second side 133 to generate spurious resonance. Referring to the reflection coefficient (S11) curve 170 in FIG. 1b, the undulating section 171 of the curve 170 corresponds to the generated spurious resonance, and the fluctuation of the reflection coefficient of the undulating section 171 will increase the insertion loss in the passband region of the SAW resonator.

Contents of the invention

The problem solved by the present invention is to provide a surface acoustic wave resonator that can reduce the bulk acoustic wave reflected to the upper surface of the piezoelectric layer, thereby reducing the spurious resonance.

In order to solve the above problems, an embodiment of the present invention provides a surface acoustic wave resonator, including: a support layer; a piezoelectric layer located above the support layer, the piezoelectric layer includes a first side opposite to the first side The second side of the support layer is located on the first side; the reflective medium layer is located on the first side, above the support layer, and embedded in the piezoelectric layer; the electrode layer is located on the second side , located on the piezoelectric layer; wherein, the reflective medium layer includes a first top portion and a first side portion, the first top portion includes a first concave-convex portion, the first side portion includes a second concave-convex portion, the The roughness of the second concave-convex portion is greater than the roughness of the first concave-convex portion.

In some embodiments, the medium of the reflective medium layer includes one of the following: vacuum and air. In some embodiments, the material of the reflective medium layer includes at least one of the following: polymer, insulating dielectric, and polysilicon.

In some embodiments, the electrode layer includes an interdigital transducing device, and the interdigital transducing device is located above the reflective medium layer and corresponds to the reflective medium layer.

In some embodiments, the arithmetic average deviation of the profile of the first concave-convex portion is greater than 1 nanometer.

In some embodiments, the arithmetic average deviation of the profile of the second concave-convex portion is greater than 2 nanometers.

In some embodiments, the support layer includes a substrate. In some embodiments, the surface acoustic wave resonator device further includes: a connection layer, located on the first side, between the substrate and the piezoelectric layer, for connecting the substrate and the piezoelectric layer. layer, the reflective medium layer is located on the connection layer or the connection layer is located on both sides of the reflective medium layer in the horizontal direction.

In some embodiments, the supporting layer further includes: an intermediate layer located between the substrate and the piezoelectric layer for blocking leakage waves or temperature compensation, and the reflective medium layer is located on the intermediate layer. In some embodiments, the material of the intermediate layer includes at least one of the following: polymer, insulating dielectric, and polysilicon.

It should be noted that the reflective medium layer is located between the piezoelectric layer and the substrate or the intermediate layer, and is embedded in the piezoelectric layer. The reflective medium layer includes irregular concave-convex portions, and the bulk acoustic wave generated by the electrode layer travels on the irregular concave-convex portions. Irregular reflections (that is, the reflection directions of the reflected waves are not uniform) at the parts can reduce the bulk acoustic waves reflected to the upper surface of the piezoelectric layer, thereby reducing the spurious resonance.

In addition, the roughness of the side of the reflective medium layer is greater than that of the top thereof, which can further increase the irregularity of reflection.

An embodiment of the present invention also provides a filtering device, including but not limited to: at least one surface acoustic wave resonator device provided in one of the above-mentioned embodiments.

An embodiment of the present invention also provides a radio frequency front-end device, including but not limited to: a power amplifying device and at least one filtering device provided in the above-mentioned embodiments; the power amplifying device is connected to the filtering device.

An embodiment of the present invention also provides a radio frequency front-end device, including but not limited to: a low-noise amplification device and at least one filtering device provided in the above-mentioned embodiments; the low-noise amplification device is connected to the filtering device.

An embodiment of the present invention also provides a radio frequency front-end device, including but not limited to: a multiplexing device, where the multiplexing device includes at least one filtering device provided in the foregoing embodiments.

Description of drawings

FIG. 1a is a schematic structural diagram of a section A of a SAW resonator 100;

Fig. 1 b is a schematic diagram of a reflection coefficient (S11) curve of a SAW resonator;

2 is a schematic structural diagram of a section A of a SAW resonator device 200 according to an embodiment of the present invention;

3 is a schematic structural diagram of a section A of a SAW resonator device 300 according to an embodiment of the present invention;

4 is a schematic structural diagram of a section A of a SAW resonator device 400 according to an embodiment of the present invention;

5 is a schematic structural diagram of a section A of a SAW resonator device 500 according to an embodiment of the present invention;

6 is a schematic structural diagram of a section A of a SAW filter device 600 according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a section A of a SAW filter device 700 according to an embodiment of the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings.

In the following description, many specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways than those described here, so the present invention is not limited by the specific embodiments disclosed below.

As mentioned in the background section, applying a voltage between two adjacent electrode strips, in addition to exciting surface acoustic waves, also generates bulk acoustic waves, along the direction perpendicular to the piezoelectric layer (that is, the direction corresponding to the thickness of the piezoelectric layer ) propagation, the bulk acoustic wave is reflected more regularly at the contact surface between the piezoelectric layer and the substrate, and the reflected bulk acoustic wave passes back to the upper surface of the piezoelectric layer to generate spurious resonance, which will increase the SAW resonator pass Insertion loss in band area.

The inventors of the present invention have found that a reflective medium layer is provided between a piezoelectric layer and a substrate or an intermediate layer, and the piezoelectric layer is embedded, the reflective medium layer includes irregular concavo-convex portions, and the bulk acoustic wave generated by the electrode layer passes through the piezoelectric layer. Irregular reflections are generated at the irregular concavo-convex parts, which can reduce bulk acoustic waves reflected to the upper surface of the piezoelectric layer, thereby reducing spurious resonance.

The inventors of the present invention also found that the roughness of the side of the reflective medium layer is greater than that of the top, which can further increase the irregularity of reflection.

An embodiment of the present invention provides a surface acoustic wave resonator device, including: a support layer; a piezoelectric layer located above the support layer, the piezoelectric layer including a first side and a second side opposite to the first side, The support layer is located on the first side; the reflective medium layer is located on the first side, above the support layer, and embedded in the piezoelectric layer; the electrode layer is located on the second side, located on the piezoelectric layer. On the electrical layer; wherein, the reflective medium layer includes a first top and a first side, the first top includes a first concave-convex portion, the first side portion includes a second concave-convex portion, and the second concave-convex portion The roughness of is greater than the roughness of the first concave-convex portion.

In some embodiments, the medium of the reflective medium layer includes but not limited to one of the following: vacuum and air.

In some embodiments, the material of the reflective medium layer includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon.

In some embodiments, the supporting layer further includes: an intermediate layer located between the substrate and the piezoelectric layer for blocking leakage waves or temperature compensation, and the reflective medium layer is located on the intermediate layer. In some embodiments, the material of the intermediate layer includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon.

Fig. 2 to Fig. 5 have shown 4 specific embodiments of the surface acoustic wave resonator device of the present invention, and described 4 specific embodiments adopt the resonator device of different structure, but the present invention can also adopt other and be different from other described here Therefore, the present invention is not limited by the specific embodiments disclosed below.

FIG. 2 is a schematic structural diagram of a section A of a SAW resonator device 200 according to an embodiment of the present invention.

As shown in FIG. 2, an embodiment of the present invention provides a SAW resonator device 200, including: a substrate 210; a reflective medium layer 230 located above the substrate 210; a piezoelectric layer 250 located above the substrate 210, and the piezoelectric layer 250 is located above the substrate 210. The electrical layer 250 includes a first side 251 and a second side 253 opposite to the first side 251, the substrate 210 is located on the first side 251, the reflective medium layer 230 is located on the first side 251, embedded in the The piezoelectric layer 250; and the electrode layer 270, located on the second side 253, located on the piezoelectric layer 250, the electrode layer 270 is located above the reflective medium layer 230; wherein, the reflective medium layer 230 It includes a top portion 231 and a side portion 233, the top portion 231 includes an irregular concave-convex portion, and the side portion 233 includes an irregular concave-convex portion.

It should be noted that, as shown in FIG. 2 , a voltage is applied on the electrode layer 270 to generate a bulk acoustic wave, and the bulk acoustic wave propagates to the top 231 or the side along a direction perpendicular to the piezoelectric layer 250 . Irregular reflections are generated at the irregular concavo-convex portions of the portion 233, which reduces the bulk acoustic waves reflected back to the surface of the second side 253, thereby reducing spurious resonance. Referring again to the reflection coefficient (S11) curve 190 in FIG. 1b, the undulating section 191 of the curve 190 corresponds to the reduced spurious resonance. Comparing the undulating section 171 and the undulating section 191, it can be seen that reducing the spurious resonance can reduce the undulating section The amplitude, thereby reducing the insertion loss in the passband region of the SAW resonator device. It should be noted that Fig. 1b is only schematic and is used for more intuitively understanding the beneficial effect of the embodiment of the present invention, but it is not equivalent to the actual performance of the SAW resonator device of the embodiment of the present invention.

In this embodiment, the material of the substrate 210 includes but is not limited to at least one of the following: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, sapphire, spinel, ceramics, and polymers. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide.

In this embodiment, the medium of the reflective medium layer 230 includes but not limited to one of the following: vacuum and air.

In this embodiment, the left and right sides of the reflective medium layer 230, that is, the two sides in the horizontal direction, are the piezoelectric layer 250, the lower side of the reflective medium layer 230 is the substrate 210, and the reflective medium layer 230 is the substrate 210. The upper side of the dielectric layer 230 is the piezoelectric layer 250 , that is, the two sides in the vertical direction of the reflective dielectric layer 230 are the substrate 210 and the piezoelectric layer 250 respectively.

In this embodiment, the material of the piezoelectric layer 250 includes but is not limited to at least one of the following: aluminum nitride, aluminum oxide, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, Lead Magnesium Niobate - Lead Titanate.

In this embodiment, the electrode layer 270 includes an interdigital transducer (IDT), corresponding to the reflective medium layer 230, and the IDT includes a plurality of first electrode strips and a plurality of second electrode strips, wherein the The plurality of first electrode strips and the plurality of second electrode strips have different polarities, and the first electrode strips and the second electrode strips are alternately placed. It should be noted that the IDT structure in the embodiment of the present invention is a specific embodiment, and the present invention can also be implemented using other IDT structures different from those described here, so the present invention is not limited by the specific embodiment, and belongs to Other IDT structures known to those skilled in the art may be applied to the embodiments of the present invention.

In this embodiment, the roughness of the side portion 233 is greater than the roughness of the top portion 231 to further increase the irregularity of reflection. In this embodiment, the arithmetic average deviation of the contour of the irregular concave-convex part of the top 231 is greater than 1 nanometer. In this embodiment, the arithmetic average deviation of the contour of the irregular concave-convex portion of the side portion 233 is greater than 2 nanometers. It should be noted that the arithmetic mean deviation of the contour refers to the arithmetic mean of the absolute value of the contour deviation within the sampling length, which is used to represent the degree of surface roughness.

In another embodiment, the SAW resonator device further includes a connecting layer, located between the substrate and the piezoelectric layer, for bonding or bonding the substrate and the piezoelectric layer, and the material of the connecting layer includes but not Limited to at least one of the following: polymer, insulating dielectric, polysilicon. Wherein, the polymer includes but not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), polyimide. The insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

FIG. 3 is a schematic structural diagram of a section A of a SAW resonator device 300 according to an embodiment of the present invention.

As shown in FIG. 3 , an embodiment of the present invention provides a SAW resonator device 300, including: a substrate 310; a connection layer 320 located on the substrate 310; a reflective medium layer 330 located above the substrate 310; a piezoelectric layer 340 , located on the connection layer 320, the piezoelectric layer 340 includes a first side 341 and a second side 343 opposite to the first side 341, the substrate 310 is located on the first side 341, the connection layer 320 is located on the first side 341, the reflective medium layer 330 is located on the first side 341, embedded in the piezoelectric layer 340, and the connection layer 320 is located on the left and right sides of the reflective medium layer 330 (that is, two sides in the horizontal direction), for bonding or bonding the substrate 310 and the piezoelectric layer 340; the electrode layer 350, located on the second side 343, is located on the piezoelectric layer 340, the The electrode layer 350 is located above the reflective medium layer 330; and the temperature compensation layer 360 is located on the second side 343, on the piezoelectric layer 340, and covers the electrode layer 350; wherein the reflective medium layer 330 It includes a top portion 331 and a side portion 333 , the top portion 331 includes an irregular concave-convex portion, and the side portion 333 includes an irregular concave-convex portion.

It should be noted that applying a voltage on the electrode layer 350 generates a bulk acoustic wave, and the bulk acoustic wave propagates along a direction perpendicular to the piezoelectric layer 340 to the irregular bumps on the top 331 or the side 333 Irregular reflection is generated at the part, which reduces the bulk acoustic wave reflected back to the surface of the second side 343, thereby reducing the spurious resonance.

In this embodiment, the material of the substrate 310 includes but is not limited to at least one of the following: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, sapphire, spinel, ceramics, and polymers. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide.

In this embodiment, in the vertical direction, the connection layer 320 is located between the base 310 and the piezoelectric layer 340 . In this embodiment, the material of the connection layer 320 includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In this embodiment, the medium of the reflective medium layer 330 includes but not limited to one of the following: vacuum and air.

In this embodiment, the left and right sides of the reflective medium layer 330, that is, the two sides in the horizontal direction, are the connection layer 320 and the piezoelectric layer 340 on the connection layer 320. The reflective medium The lower side of the layer 330 is the base 310, and the upper side of the reflective medium layer 330 is the piezoelectric layer 340, that is, the two sides in the vertical direction of the reflective medium layer 330 are respectively the base 310 and the piezoelectric layer 340. The piezoelectric layer 340 .

In this embodiment, the material of the piezoelectric layer 340 includes but is not limited to at least one of the following: aluminum nitride, aluminum oxide, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, Lead Magnesium Niobate - Lead Titanate.

In this embodiment, the electrode layer 350 includes an interdigital transducer (IDT), corresponding to the reflective medium layer 330, and the IDT includes a plurality of first electrode strips and a plurality of second electrode strips, wherein the The plurality of first electrode strips and the plurality of second electrode strips have different polarities, and the first electrode strips and the second electrode strips are alternately placed. It should be noted that the IDT structure in the embodiment of the present invention is a specific embodiment, and the present invention can also be implemented using other IDT structures different from those described here, so the present invention is not limited by the specific embodiment, and belongs to Other IDT structures known to those skilled in the art may be applied to the embodiments of the present invention.

It should be noted that the material (for example, silicon dioxide) of the temperature compensation layer 360 and the material of the piezoelectric layer 340 have opposite temperature frequency shift characteristics, which can reduce the frequency temperature coefficient (Temperature Coefficient of Frequency, TCF), tends to 0ppm/℃, thus improving the frequency-temperature stability.

In this embodiment, the roughness of the side portion 333 is greater than the roughness of the top portion 331 to further increase the irregularity of reflection. In this embodiment, the arithmetic average deviation of the contour of the irregular concave-convex part of the top 331 is greater than 1 nanometer. In this embodiment, the arithmetic average deviation of the contour of the irregular concave-convex portion of the side portion 333 is greater than 2 nanometers. It should be noted that the arithmetic mean deviation of the contour refers to the arithmetic mean of the absolute value of the contour deviation within the sampling length, which is used to represent the degree of surface roughness.

As shown in FIG. 4 , an embodiment of the present invention provides a SAW resonator device 400, including: a substrate 410; a connection layer 430 located on the substrate 410; a reflective medium layer 450 located on the connection layer 430; a piezoelectric layer 470, located on the connection layer 430, the piezoelectric layer 470 includes a first side 471 and a second side 473 opposite to the first side 471, the base 410 is located on the first side 471, the connection Layer 430 is located on the first side 471, the reflective medium layer 450 is located on the first side 471, embedded in the piezoelectric layer 470; and an electrode layer 490 is located on the second side 473, located on the piezoelectric layer 470; On the layer 470, the electrode layer 490 is located above the reflective medium layer 450; wherein, the reflective medium layer 450 includes a top 451 and a side 453, and the top 451 includes an irregular concave-convex portion.

It should be noted that applying a voltage on the electrode layer 490 generates a bulk acoustic wave, and the bulk acoustic wave propagates along a direction perpendicular to the piezoelectric layer 470 to the irregular concave-convex portion of the top 451 to generate irregular reflection , reducing the bulk acoustic wave reflected back to the surface of the second side 473, thereby reducing the spurious resonance.

In this embodiment, the material of the substrate 410 includes but is not limited to at least one of the following: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, sapphire, spinel, ceramics, and polymers. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide.

In this embodiment, in the vertical direction, the connection layer 430 is located between the substrate 410 and the piezoelectric layer 470 . In this embodiment, the material of the connection layer 430 includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In this embodiment, the material of the reflective medium layer 450 includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In this embodiment, the material of the reflective medium layer 450 is different from that of the connecting layer 430 . In another embodiment, the material of the reflective medium layer and the material of the connection layer may be the same. It should be noted that filling the reflective medium layer can enhance the connection strength between the substrate and the piezoelectric layer.

In another embodiment, the medium of the reflective medium layer includes but not limited to one of the following: vacuum, air.

In this embodiment, the left and right sides of the reflective medium layer 450, that is, the two sides in the horizontal direction, are the piezoelectric layer 470, the lower side of the reflective medium layer 450 is the connection layer 430, and the The upper side of the reflective medium layer 450 is the piezoelectric layer 470 , that is, the two sides in the vertical direction of the reflective medium layer 450 are the connection layer 430 and the piezoelectric layer 470 respectively.

In this embodiment, the material of the piezoelectric layer 470 includes but is not limited to at least one of the following: aluminum nitride, aluminum oxide, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, Lead Magnesium Niobate - Lead Titanate.

In this embodiment, the electrode layer 490 includes an interdigital transducer (IDT), corresponding to the reflective medium layer 450, and the IDT includes a plurality of first electrode strips and a plurality of second electrode strips, wherein the The plurality of first electrode strips and the plurality of second electrode strips have different polarities, and the first electrode strips and the second electrode strips are alternately placed. It should be noted that the IDT structure in the embodiment of the present invention is a specific embodiment, and the present invention can also be implemented using other IDT structures different from those described here, so the present invention is not limited by the specific embodiment, and belongs to Other IDT structures known to those skilled in the art may be applied to the embodiments of the present invention.

In this embodiment, the arithmetic average deviation of the contour of the irregular concave-convex part of the top 451 is greater than 1 nanometer. It should be noted that the arithmetic mean deviation of the contour refers to the arithmetic mean of the absolute value of the contour deviation within the sampling length, which is used to represent the degree of surface roughness.

FIG. 5 is a schematic structural diagram of a section A of a SAW resonator device 500 according to an embodiment of the present invention.

As shown in FIG. 5 , an embodiment of the present invention provides a SAW resonator device 500, including: a substrate 510; an intermediate layer 530 located on the substrate 510 for blocking leaky waves or temperature compensation; a reflective medium layer 550 located on the The piezoelectric layer 570 is located on the intermediate layer 530, the piezoelectric layer 570 includes a first side 571 and a second side 573 opposite to the first side 571, and the substrate 510 is located on the intermediate layer 530. The first side 571, the intermediate layer 530 is located on the first side 571, the reflective medium layer 550 is located on the first side 571, embedded in the piezoelectric layer 570; and the electrode layer 590 is located on the first side Two sides 573 are located on the piezoelectric layer 570, and the electrode layer 590 is located above the reflective medium layer 550; wherein, the reflective medium layer 550 includes a top 551 and a side 553, and the top 551 includes irregular Concave-convex part, the side part 553 includes irregular concavo-convex part.

It should be noted that applying a voltage on the electrode layer 590 generates bulk acoustic waves, and the bulk acoustic waves propagate along a direction perpendicular to the piezoelectric layer 570 to the irregular bumps on the top 551 or the side 553 Irregular reflection is generated at the part, which reduces the bulk acoustic wave reflected back to the surface of the second side 573, thereby reducing the spurious resonance.

In this embodiment, the material of the substrate 510 includes but is not limited to at least one of the following: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, sapphire, spinel, ceramics, and polymers. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide.

In this embodiment, the material of the intermediate layer 530 includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In this embodiment, the material of the reflective medium layer 550 includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In this embodiment, the material of the reflective medium layer 550 is different from that of the intermediate layer 530 . In another embodiment, the material of the reflective medium layer and the material of the intermediate layer may be the same. It should be noted that filling the reflective medium layer can enhance the connection strength between the intermediate layer and the piezoelectric layer.

In this embodiment, the left and right sides of the reflective medium layer 550, that is, the two sides in the horizontal direction, are the piezoelectric layer 570, the lower side of the reflective medium layer 550 is the intermediate layer 530, and the The upper side of the reflective medium layer 550 is the piezoelectric layer 570 , that is, the two sides in the vertical direction of the reflective medium layer 550 are the intermediate layer 530 and the piezoelectric layer 570 respectively.

In this embodiment, the material of the piezoelectric layer 570 includes but is not limited to at least one of the following: aluminum nitride, aluminum oxide, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, Lead Magnesium Niobate - Lead Titanate. It should be noted that the acoustic impedance of the material of the intermediate layer 530 is different from that of the piezoelectric layer 570 , which can block leakage waves. In addition, if the material of the intermediate layer 530 (for example, silicon dioxide) and the material of the piezoelectric layer 570 have opposite temperature frequency shift characteristics, the TCF of the resonant device can be reduced, tending to 0 ppm/°C, thereby Improve frequency-temperature stability, that is, the middle layer 530 is a temperature compensation layer.

In this embodiment, the electrode layer 590 includes an interdigital transducer (IDT), corresponding to the reflective medium layer 550, and the IDT includes a plurality of first electrode strips and a plurality of second electrode strips, wherein the The plurality of first electrode strips and the plurality of second electrode strips have different polarities, and the first electrode strips and the second electrode strips are alternately placed. It should be noted that the IDT structure in the embodiment of the present invention is a specific embodiment, and the present invention can also be implemented using other IDT structures different from those described here, so the present invention is not limited by the specific embodiment, and belongs to Other IDT structures known to those skilled in the art may be applied to the embodiments of the present invention.

In this embodiment, the roughness of the side portion 553 is greater than the roughness of the top portion 551 to further increase the irregularity of reflection. In this embodiment, the arithmetic average deviation of the contour of the irregular concave-convex part of the top 551 is greater than 1 nanometer. In this embodiment, the arithmetic average deviation of the contour of the irregular concave-convex portion of the side portion 553 is greater than 2 nanometers. It should be noted that the arithmetic mean deviation of the contour refers to the arithmetic mean of the absolute value of the contour deviation within the sampling length, which is used to represent the degree of surface roughness.

In this embodiment, the SAW resonator device 500 further includes: a connecting layer 520 located between the base 510 and the intermediate layer 530 for bonding the base 510 and the intermediate layer 530 . In this embodiment, the material of the connection layer 520 includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

Fig. 6 and Fig. 7 have shown 2 specific embodiments of the filtering device of the present invention, and described 2 specific embodiments adopt the filtering device of different structures, but the present invention can also be implemented in other ways different from those described here , so the present invention is not limited by the specific examples disclosed below.

FIG. 6 is a schematic structural diagram of a section A of a SAW filter device 600 according to an embodiment of the present invention.

As shown in FIG. 6, an embodiment of the present invention provides a SAW filter device 600, including: a substrate 610; a connection layer 630 located on the substrate 610; a plurality of reflective medium layers 650 located on the connection layer 630, the The plurality of reflective medium layers 650 include a reflective medium layer 651, a reflective medium layer 653, a reflective medium layer 655, and a reflective medium layer 657; a piezoelectric layer 670 is located on the connection layer 630, and the piezoelectric layer 670 includes a first side 671 and the second side 673 opposite to the first side 671, the substrate 610 is located on the first side 671, the connection layer 630 is located on the first side 671, and the multiple reflective medium layers 650 are located on The first side 671 is respectively embedded in the piezoelectric layer 670; and the electrode layer 690 is located on the second side 673 and on the piezoelectric layer 670, and the electrode layer 690 includes IDT 691, IDT 693, IDT 695 and IDT 697, the IDT 691 is located above the reflective medium layer 651, corresponding to the reflective medium layer 651; the IDT 693 is located above the reflective medium layer 653, corresponding to the reflective medium layer 653; The IDT 695 is located above the reflective medium layer 655, corresponding to the reflective medium layer 655; the IDT 697 is located above the reflective medium layer 657, corresponding to the reflective medium layer 657; wherein, the reflective medium layer 651 includes the first A top and a first side, the first top includes irregular unevenness; the reflective medium layer 653 includes a second top and a second side, the second top includes irregular unevenness; the reflective medium The layer 655 includes a third top portion and a third side portion, the third top portion includes irregular concave-convex portions; the reflective medium layer 657 includes a fourth top portion and a fourth side portion, and the fourth top portion includes irregular concave-convex portions.

It should be noted that applying a voltage on the electrode layer 690 generates a bulk acoustic wave, and the bulk acoustic wave propagates to the irregular concave-convex portions of the plurality of reflective medium layers 650 along a direction perpendicular to the piezoelectric layer 670 Irregular reflection is generated, which reduces the bulk acoustic wave reflected back to the surface of the second side 673, thereby reducing spurious resonance.

In this embodiment, the material of the substrate 610 includes but is not limited to at least one of the following: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, sapphire, spinel, ceramics, and polymers. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide.

In this embodiment, in the vertical direction, the connection layer 630 is located between the base 610 and the plurality of reflective medium layers 650 . In this embodiment, the material of the connection layer 630 includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In this embodiment, the materials of the plurality of reflective medium layers 650 include but are not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In this embodiment, the material of the plurality of reflective medium layers 650 is different from that of the connection layer 630 . In another embodiment, the material of the plurality of reflective medium layers and the material of the connecting layer may be the same. It should be noted that filling multiple reflective medium layers can enhance the connection strength between the substrate and the piezoelectric layer.

In another embodiment, the medium of the plurality of reflective medium layers includes but not limited to one of the following: vacuum, air.

In this embodiment, the left and right sides of the reflective medium layer 651, that is, the two sides in the horizontal direction, are the piezoelectric layer 670, the lower side of the reflective medium layer 651 is the connection layer 630, and the The upper side of the reflective medium layer 651 is the piezoelectric layer 670 , that is, the two sides in the vertical direction of the reflective medium layer 651 are the connection layer 630 and the piezoelectric layer 670 respectively.

In this embodiment, the left and right sides of the reflective medium layer 653, that is, the two sides in the horizontal direction, are the piezoelectric layer 670, the lower side of the reflective medium layer 653 is the connection layer 630, and the The upper side of the reflective medium layer 653 is the piezoelectric layer 670 , that is, the two sides in the vertical direction of the reflective medium layer 653 are the connection layer 630 and the piezoelectric layer 670 respectively.

In this embodiment, the left and right sides of the reflective medium layer 655, that is, the two sides in the horizontal direction, are the piezoelectric layer 670, the lower side of the reflective medium layer 655 is the connection layer 630, and the The upper side of the reflective medium layer 655 is the piezoelectric layer 670 , that is, the two sides in the vertical direction of the reflective medium layer 655 are the connection layer 630 and the piezoelectric layer 670 respectively.

In this embodiment, the left and right sides of the reflective medium layer 657, that is, the two sides in the horizontal direction, are the piezoelectric layer 670, the lower side of the reflective medium layer 657 is the connection layer 630, and the The upper side of the reflective medium layer 657 is the piezoelectric layer 670 , that is, the two sides in the vertical direction of the reflective medium layer 657 are the connection layer 630 and the piezoelectric layer 670 respectively.

In this embodiment, the material of the piezoelectric layer 670 includes but is not limited to at least one of the following: aluminum nitride, aluminum oxide, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, Lead Magnesium Niobate - Lead Titanate.

It should be noted that the IDT structures known to those skilled in the art can be applied to the embodiments of the present invention. In another embodiment, the electrode layer includes 3 or less sets of interdigitated structures, and correspondingly, the multiple reflective medium layers include 3 or less reflective medium layers. In another embodiment, the electrode layer includes 5 or more sets of interdigitated structures, and correspondingly, the multiple reflective medium layers include 5 or more reflective medium layers.

In this embodiment, the arithmetic mean deviation of the contour of the irregular concave-convex part of the first top is greater than 1 nanometer. It should be noted that the arithmetic mean deviation of the contour refers to the arithmetic mean of the absolute value of the contour deviation within the sampling length, which is used to represent the degree of surface roughness. In this embodiment, the arithmetic mean deviation of the contour of the irregular concave-convex portion on the second top is greater than 1 nanometer. In this embodiment, the arithmetic mean deviation of the contour of the irregular concave-convex part of the third top is greater than 1 nanometer. In this embodiment, the arithmetic mean deviation of the contour of the irregular concave-convex part of the fourth top is greater than 1 nanometer.

As shown in FIG. 7 , an embodiment of the present invention provides a SAW filter device 700, including: a substrate 710; an intermediate layer 730 located on the substrate 710 for blocking leaky waves or temperature compensation; multiple reflective medium layers 750, Located on the intermediate layer 730, the multiple reflective medium layers 750 include a reflective medium layer 751, a reflective medium layer 753, and a reflective medium layer 755; a piezoelectric layer 770 is located on the intermediate layer 730, and the piezoelectric layer 770 includes a first side 771 and a second side 773 opposite to the first side 771, the substrate 710 is located on the first side 771, the intermediate layer 730 is located on the first side 771, and the plurality of reflectors The dielectric layer 750 is located on the first side 771 and embedded in the piezoelectric layer 770; and the electrode layer 790 is located on the second side 773 and is located on the piezoelectric layer 770. The electrode layer 790 includes an IDT 791, IDT 793 and IDT 795, the IDT 791 is located above the reflective medium layer 751, corresponding to the reflective medium layer 751; the IDT 793 is located above the reflective medium layer 753, corresponding to the reflective medium layer 753; The IDT 795 is located above the reflective medium layer 755, corresponding to the reflective medium layer 755; wherein, the reflective medium layer 751 includes a first top and a first side, and the first top includes an irregular concave-convex portion, the The first side portion includes irregular concave-convex portions; the reflective medium layer 753 includes a second top and a second side portion, the second top portion includes irregular concave-convex portions, and the second side portion includes irregular concave-convex portions; The reflective medium layer 755 includes a third top portion and a third side portion, the third top portion includes an irregular concave-convex portion, and the third side portion includes an irregular concave-convex portion.

It should be noted that applying a voltage on the electrode layer 790 generates a bulk acoustic wave, and the bulk acoustic wave propagates to the irregular concave-convex portions of the plurality of reflective medium layers 750 along a direction perpendicular to the piezoelectric layer 770 Irregular reflection is generated, which reduces the bulk acoustic wave reflected back to the surface of the second side 773, thereby reducing spurious resonance.

In this embodiment, the material of the substrate 710 includes but is not limited to at least one of the following: silicon, silicon carbide, silicon dioxide, gallium arsenide, gallium nitride, sapphire, spinel, ceramics, and polymers. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide.

In this embodiment, the material of the intermediate layer 730 includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In this embodiment, the materials of the plurality of reflective medium layers 750 include but are not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In this embodiment, the material of the plurality of reflective medium layers 750 is different from that of the intermediate layer 730 . In another embodiment, the material of the plurality of reflective medium layers and the material of the intermediate layer may be the same. It should be noted that filling multiple reflective medium layers can enhance the connection strength between the intermediate layer and the piezoelectric layer.

In this embodiment, the left and right sides of the reflective medium layer 751, that is, the two sides in the horizontal direction, are the piezoelectric layer 770, the lower side of the reflective medium layer 751 is the intermediate layer 730, and the The upper side of the reflective medium layer 751 is the piezoelectric layer 770 , that is, the two sides in the vertical direction of the reflective medium layer 751 are the intermediate layer 730 and the piezoelectric layer 770 respectively.

In this embodiment, the left and right sides of the reflective medium layer 753, that is, the two sides in the horizontal direction, are the piezoelectric layer 770, the lower side of the reflective medium layer 753 is the intermediate layer 730, and the The upper side of the reflective medium layer 753 is the piezoelectric layer 770 , that is, the two sides in the vertical direction of the reflective medium layer 753 are the intermediate layer 730 and the piezoelectric layer 770 respectively.

In this embodiment, the left and right sides of the reflective medium layer 755, that is, the two sides in the horizontal direction, are the piezoelectric layer 770, the lower side of the reflective medium layer 755 is the intermediate layer 730, and the The upper side of the reflective medium layer 755 is the piezoelectric layer 770 , that is, the two sides in the vertical direction of the reflective medium layer 755 are the intermediate layer 730 and the piezoelectric layer 770 respectively.

In this embodiment, the material of the piezoelectric layer 770 includes but is not limited to at least one of the following: aluminum nitride, aluminum oxide, gallium nitride, zinc oxide, lithium tantalate, lithium niobate, lead zirconate titanate, Lead Magnesium Niobate - Lead Titanate. It should be noted that the acoustic impedance of the material of the intermediate layer 730 is different from that of the piezoelectric layer 770 , which can block leakage waves. In addition, if the material of the intermediate layer 730 (for example, silicon dioxide) and the material of the piezoelectric layer 770 have opposite temperature frequency shift characteristics, the TCF of the resonant device can be reduced, tending to 0ppm/°C, thereby improving Frequency-temperature stability, that is, the middle layer 730 is a temperature compensation layer.

It should be noted that the IDT structures known to those skilled in the art can be applied to the embodiments of the present invention. In another embodiment, the electrode layer includes 2 or less sets of interdigitated structures, and correspondingly, the multiple reflective medium layers include 2 or less reflective medium layers. In another embodiment, the electrode layer includes 4 or more sets of interdigitated structures, and correspondingly, the multiple reflective medium layers include 4 or more reflective medium layers.

In this embodiment, the arithmetic mean deviation of the contour of the irregular concave-convex part of the first top is greater than 1 nanometer. In this embodiment, the arithmetic average deviation of the contour of the irregular concave-convex portion on the first side portion is greater than 1 nanometer. It should be noted that the arithmetic mean deviation of the contour refers to the arithmetic mean of the absolute value of the contour deviation within the sampling length, which is used to represent the degree of surface roughness.

In this embodiment, the arithmetic mean deviation of the contour of the irregular concave-convex portion on the second top is greater than 1 nanometer. In this embodiment, the arithmetic mean deviation of the contour of the irregular concave-convex part of the second side part is greater than 1 nanometer.

In this embodiment, the arithmetic mean deviation of the contour of the irregular concave-convex part of the third top is greater than 1 nanometer. In this embodiment, the arithmetic average deviation of the contour of the irregular concave-convex part of the third side part is greater than 1 nanometer.

In this embodiment, the SAW filter device 700 further includes: a connecting layer 720 located between the substrate 710 and the intermediate layer 730 for bonding the substrate 710 and the intermediate layer 730 . In this embodiment, the material of the connection layer 720 includes but is not limited to at least one of the following: polymer, insulating dielectric, and polysilicon. In this embodiment, the polymer includes but is not limited to at least one of the following: benzocyclobutene (ie, BCB), photosensitive epoxy photoresist (eg, SU-8), and polyimide. In this embodiment, the insulating dielectric includes but is not limited to at least one of the following: aluminum nitride, silicon dioxide, silicon nitride, and titanium oxide.

In summary, an embodiment of the present invention provides a surface acoustic wave resonator device including a reflective medium layer, located between the piezoelectric layer and the substrate or an intermediate layer, and embedded in the piezoelectric layer, and the reflective medium layer includes irregular unevenness part, the bulk acoustic wave generated by the electrode layer generates irregular reflection at the irregular concave-convex part, which can reduce the bulk acoustic wave reflected to the upper surface of the piezoelectric layer, thereby reducing the spurious resonance.

It should be understood that the examples and embodiments herein are illustrative only, and that various modifications and correct.

Claims

A surface acoustic wave resonator, characterized in that it comprises:

support layer;

a piezoelectric layer located above the support layer, the piezoelectric layer comprising a first side and a second side opposite to the first side, the support layer located on the first side;

a reflective medium layer, located on the first side, above the supporting layer, embedded in the piezoelectric layer;

an electrode layer, on the second side, on the piezoelectric layer;

Wherein, the reflective medium layer includes a first top portion and a first side portion, the first top portion includes a first concave-convex portion, the first side portion includes a second concave-convex portion, and the roughness of the second concave-convex portion is greater than The roughness of the first concave-convex part.
The surface acoustic wave resonator device according to claim 1, wherein the medium of the reflective medium layer comprises one of the following: vacuum and air.
The surface acoustic wave resonator device according to claim 1, wherein the material of the reflective medium layer comprises at least one of the following: polymer, insulating dielectric, and polysilicon.
The surface acoustic wave resonator device according to claim 1, wherein the electrode layer comprises an interdigital transducer, and the interdigital transducer is located above the reflective medium layer and corresponds to the reflective medium layer.
The surface acoustic wave resonator device according to claim 1, wherein the arithmetic average deviation of the profile of the first concave-convex portion is greater than 1 nanometer.
The surface acoustic wave resonator device according to claim 1, wherein the arithmetic average deviation of the profile of the second concave-convex portion is greater than 2 nanometers.
The surface acoustic wave resonator device according to claim 1, wherein the supporting layer comprises a substrate.
The surface acoustic wave resonator device according to claim 7, further comprising: a connection layer, located on the first side, between the substrate and the piezoelectric layer, for connecting the substrate and the piezoelectric layer. For the piezoelectric layer, the reflective medium layer is located on the connection layer or the connection layer is located on both sides of the reflective medium layer in the horizontal direction.
The surface acoustic wave resonator device according to claim 7, wherein the support layer further comprises: an intermediate layer, located between the substrate and the piezoelectric layer, for blocking leakage waves or temperature compensation, so The reflective medium layer is located on the intermediate layer.
The surface acoustic wave resonator device according to claim 9, wherein the material of the intermediate layer comprises at least one of the following: polymer, insulating dielectric, polysilicon.
A filter device, characterized by comprising: at least one surface acoustic wave resonator device according to any one of claims 1 to 10.
A radio frequency front-end device, characterized by comprising: a power amplifying device and at least one filtering device according to claim 11; the power amplifying device is connected to the filtering device.
A radio frequency front-end device, characterized by comprising: a low-noise amplification device and at least one filtering device according to claim 11; the low-noise amplification device is connected to the filtering device.
A radio frequency front-end device, characterized by comprising: a multiplexing device, the multiplexing device including at least one filter device as claimed in claim 11.