Surface acoustic wave resonance device, forming method thereof and filtering device

Abstract

The invention discloses a surface acoustic wave resonance device, a forming method thereof and a filtering device, and the device comprises a piezoelectric layer which is made of lithium niobate and has a crystal cut angle of 165-175 degrees YX; the interdigital electrode structure is located on the piezoelectric layer, the interdigital electrode structure at least comprises a first metal layer, and the material density of the first metal layer is larger than 15000 kg / m < 3 >; and the temperature compensation layer is positioned on the piezoelectric layer and covers the interdigital electrode structure. The piezoelectric layer is made of lithium niobate with the crystal cut angle of 165-175 degrees YX, and a large electromechanical coupling coefficient (Kt) is obtained. Besides, the material density of the first metal layer is larger than 15000 kg / m < 3 >, and the first metal layer can enable the interdigital electrode structure to become heavy, so that the acoustic wave velocity of a main resonance mode is reduced, the chip size is reduced, the electromechanical coupling coefficient (Kt) is further increased, and the large-bandwidth and small-size filtering device is achieved.

Description

Technical Field

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

[0002] The RF front-end chips of wireless communication devices include power amplifiers, antenna switches, RF filters, multiplexers, and low-noise amplifiers, etc. Among them, RF filters include piezoelectric surface acoustic wave (SAW) filters, piezoelectric bulk acoustic wave (BAW) filters, micro-electro-mechanical system (MEMS) filters, integrated passive devices (IPD) filters, etc.

[0003] The quality factor (Q value) of the SAW resonator is relatively high. The RF filter made of SAW resonator has low insertion loss and high out-band rejection, that is, SAW filter, which is the mainstream RF filter used in wireless communication devices such as mobile phones and base stations. The SAW resonator has a negative temperature coefficient of frequency (TCF), that is, when the temperature rises, the resonant frequency of the resonator decreases, and when the temperature decreases, the resonant frequency increases. This reduces the reliability and stability of the SAW filter. In order to improve the characteristics of the resonant frequency of the SAW resonator drifting with the operating temperature, a temperature compensation layer is added to the piezoelectric layer. The temperature compensation layer has a frequency temperature coefficient opposite to that of the piezoelectric layer. The combination of the two makes the overall frequency temperature coefficient of the resonator tend to zero, improving the reliability and stability of the filter. This SAW resonator containing a temperature compensation layer is called a temperature compensated SAW (TC-SAW) resonator, and the filter composed of TC-SAW resonators is called a TC-SAW filter.

[0004] However, there are still many problems with surface acoustic wave resonator devices. Summary of the invention

[0005] The problem solved by the present invention is to provide a surface acoustic wave resonant device and a forming method thereof, and a filtering device, so as to improve the electromechanical coupling coefficient (Kt) of the resonant device.

[0006] To solve the above problems, the technical solution of the present invention provides a surface acoustic wave resonance device, including: a piezoelectric layer, the material of the piezoelectric layer includes lithium niobate, and the crystal cutting angle of the piezoelectric layer includes 165°~175°YX; an interdigitated electrode structure located on the piezoelectric layer, the interdigitated electrode structure includes at least a first metal layer, and the material density of the first metal layer is greater than 15,000 kilograms per cubic meter; a temperature compensation layer located on the piezoelectric layer, and the temperature compensation layer covers the interdigitated electrode structure.

[0007] Optionally, the main mode excited by the interdigitated electrode structure is a transverse shear wave.

[0008] Optionally, a material of the first metal layer includes: tungsten, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0009] Optionally, the interdigitated electrode structure further includes: a second metal layer located on the first metal layer.

[0010] Optionally, the material density of the first metal layer is greater than the material density of the second metal layer; and the electrical conductivity of the second metal layer is greater than the electrical conductivity of the first metal layer.

[0011] Optionally, the material of the second metal layer includes at least one of aluminum, magnesium, silver, copper, titanium, beryllium and scandium.

[0012] Optionally, the interdigitated electrode structure further includes: a third metal layer located on the second metal layer.

[0013] Optionally, the yield strength of the third metal layer material is greater than the yield strength of the second metal layer material; and the electrical conductivity of the second metal layer is greater than the electrical conductivity of the third metal layer.

[0014] Optionally, the material of the third metal layer includes: titanium, molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0015] Optionally, the thickness of the second metal layer is smaller than the thickness of the first metal layer; and the thickness of the third metal layer is smaller than the thickness of the first metal layer.

[0016] Optionally, the thickness of the first metal layer is in a range of 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure.

[0017] Optionally, the thickness of the temperature compensation layer is in the range of 15% to 40% of the wavelength of the sound wave excited by the interdigital electrode structure.

[0018] Optionally, the material of the temperature compensation layer includes silicon dioxide, silicon oxyfluoride, silicon oxynitride or silicon oxycarbide.

[0019] Correspondingly, the technical solution of the present invention also provides a method for forming a surface acoustic wave resonant device, including: providing a piezoelectric layer, the material of the piezoelectric layer includes lithium niobate, and the crystal cutting angle of the piezoelectric layer includes 165°~175°YX; forming an interdigitated electrode structure on the piezoelectric layer, the interdigitated electrode structure includes at least a first metal layer, and the material density of the first metal layer is greater than 15,000 kilograms per cubic meter; forming a temperature compensation layer on the piezoelectric layer, and the temperature compensation layer covers the interdigitated electrode structure.

[0020] Optionally, the main mode excited by the interdigitated electrode structure is a transverse shear wave.

[0021] Optionally, the interdigitated electrode structure further includes: a second metal layer located on the first metal layer.

[0022] Optionally, the material density of the first metal layer is greater than the material density of the second metal layer; and the electrical conductivity of the second metal layer is greater than the electrical conductivity of the first metal layer.

[0023] Optionally, the interdigitated electrode structure further includes: a third metal layer located on the second metal layer.

[0024] Optionally, the yield strength of the third metal layer material is greater than the yield strength of the second metal layer material; and the electrical conductivity of the second metal layer is greater than the electrical conductivity of the third metal layer.

[0025] Optionally, the thickness of the second metal layer is smaller than the thickness of the first metal layer; and the thickness of the third metal layer is smaller than the thickness of the first metal layer.

[0026] Optionally, the thickness of the first metal layer is in a range of 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure.

[0027] Optionally, the thickness of the temperature compensation layer is in the range of 15% to 40% of the wavelength of the sound wave excited by the interdigital electrode structure.

[0028] Correspondingly, the technical solution of the present invention further provides a filtering device, characterized in that it includes a plurality of surface acoustic wave resonator devices as described in any one of the technical solutions above.

[0029] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0030] In the surface acoustic wave resonator device of the technical solution of the present invention, the material of the piezoelectric layer adopts lithium niobate with a crystal cutting angle of 165° to 175°YX to obtain a larger electromechanical coupling coefficient (Kt); in addition, the material density of the first metal layer is greater than 15,000 kilograms per cubic meter, and the first metal layer can make the interdigitated electrode structure heavier, thereby reducing the acoustic wave velocity of the main resonant mode, reducing the chip size, and further increasing the electromechanical coupling coefficient (Kt), thereby realizing a large bandwidth and small size filtering device.

[0031] In the method for forming a surface acoustic wave resonant device of the technical solution of the present invention, the material of the piezoelectric layer adopts lithium niobate with a crystal cutting angle of 165° to 175°YX to obtain a larger electromechanical coupling coefficient (Kt); in addition, the material density of the first metal layer is greater than 15,000 kilograms per cubic meter, and the first metal layer can make the forked electrode structure heavier, thereby reducing the acoustic wave velocity of the main resonant mode, reducing the chip size, and further increasing the electromechanical coupling coefficient (Kt), thereby realizing a large bandwidth and small size filtering device.

[0032] In the filtering device of the technical solution of the present invention, since the material of the piezoelectric layer in the surface acoustic wave resonance device adopts lithium niobate with a crystal cutting angle of 165° to 175°YX, a larger electromechanical coupling coefficient (Kt) is obtained; in addition, the material density of the first metal layer in the surface acoustic wave resonance device is greater than 15,000 kilograms per cubic meter, and the first metal layer can make the interdigitated electrode structure heavier, thereby reducing the acoustic wave velocity of the main resonance mode, reducing the chip size, and further increasing the electromechanical coupling coefficient (Kt), thereby realizing a large bandwidth and small size filtering device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the structure of a surface acoustic wave resonance device;

[0034] Figures 2 to 5 is a structural schematic diagram of each step of a method for forming a surface acoustic wave resonator device in an embodiment of the present invention;

[0035] Figure 6 is a schematic structural diagram of a surface acoustic wave resonance device in an embodiment of the present invention;

[0036] Figure 7 is a schematic structural diagram of a surface acoustic wave resonator device in another embodiment of the present invention

[0037] Figure 8 is a schematic structural diagram of a filtering device in an embodiment of the present invention;

[0038] Fig. 9 It is a schematic structural diagram of a filtering device in another embodiment of the present invention. DETAILED DESCRIPTION

[0039] As described in the background art, there are still many problems with the surface acoustic wave resonance device, which will be described in detail below with reference to the accompanying drawings.

[0040] Figure 1 It is a structural schematic diagram of a surface acoustic wave resonance device.

[0041] Please refer to Figure 1 A surface acoustic wave resonance device includes: a piezoelectric layer 100, wherein the material of the piezoelectric layer 100 includes lithium niobate, and the crystal cutting angle of the piezoelectric layer 100 includes a Y-cut of 127° to 129°; an interdigitated electrode structure 101 located on the piezoelectric layer 100; and a temperature compensation layer 102 located on the piezoelectric layer 102, wherein the temperature compensation layer 102 covers the interdigitated electrode structure 101.

[0042] In this embodiment, the material of the piezoelectric layer 100 is lithium niobate with a crystal cutting angle of 127° to 129° Y-cut, and the electromechanical coupling coefficient (Kt) of the surface acoustic wave resonator device is small (about 10%). For low-frequency band (500MHz-1000MHz) filtering devices, it cannot meet the requirements of reducing chip size.

[0043] On this basis, the present invention provides a surface acoustic wave resonance device and a method for forming it, and a filtering device. The material of the piezoelectric layer adopts lithium niobate with a crystal cutting angle of 165° to 175°YX to obtain a larger electromechanical coupling coefficient (Kt); in addition, the material density of the first metal layer is greater than 15,000 kilograms per cubic meter, and the first metal layer can make the interdigitated electrode structure heavier, thereby reducing the acoustic wave velocity of the main resonant mode, reducing the chip size, and further increasing the electromechanical coupling coefficient (Kt), thereby realizing a large bandwidth and small size filtering device.

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0046] Figures 2 to 5 It is a structural schematic diagram of each step of the method for forming a surface acoustic wave resonance device in an embodiment of the present invention.

[0047] Please refer to Figure 2 , providing a piezoelectric layer 200, wherein the material of the piezoelectric layer 200 includes lithium niobate, and the crystal cutting angle of the piezoelectric layer 200 includes 165° to 175°YX.

[0048] In this embodiment, the crystal cutting angle of the piezoelectric layer 200 is 170°YX.

[0049] The material of the piezoelectric layer 200 is lithium niobate with a crystal cutting angle of 165° to 175° YX, which can obtain a larger electromechanical coupling coefficient (Kt) than lithium niobate with a crystal cutting angle of 127° to 129° YX.

[0050] Please refer to Figure 3 and Figure 4 , Figure 4 yes Figure 3 In the cross-sectional diagram along line AA, an interdigitated electrode structure 201 is formed on the piezoelectric layer 200 . The interdigitated electrode structure 201 at least includes a first metal layer 201 a . The material density of the first metal layer 201 a is greater than 15,000 kilograms per cubic meter.

[0051] The material density of the first metal layer 201a is greater than 15,000 kilograms per cubic meter, which can make the interdigitated electrode structure 201 heavier, thereby reducing the acoustic wave velocity of the main resonant mode, reducing the chip size, and further increasing the electromechanical coupling coefficient (Kt), thereby realizing a large-bandwidth, small-size filtering device.

[0052] In this embodiment, the material of the first metal layer 201 a includes: tungsten, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0053] In this embodiment, the main mode excited by the interdigital electrode structure 201 is a transverse shear wave (SH wave).

[0054] Please continue to refer to Figure 3 In this embodiment, forming the interdigitated electrode structure 201 includes: forming a first bus 2011 and a second bus 2012 arranged in parallel along a first direction X; forming a plurality of first electrode strips 2013 connected to the first bus 2011, wherein the plurality of first electrode strips 2013 are arranged in parallel along a second direction Y, wherein the first direction X is perpendicular to the second direction Y; forming a plurality of second electrode strips 2014 connected to the second bus 2012, wherein the plurality of second electrode strips 2014 are arranged in parallel along the second direction Y, wherein the first electrode strips 2013 and the second electrode strips 2014 are alternately arranged, and wherein the first electrode strips 2013 and the second electrode strips 2014 have overlapping areas along the second direction Y.

[0055] Please continue to refer to Figure 4In this embodiment, before forming the interdigital electrode structure 201, it further includes: forming an adhesion layer 202 on the piezoelectric layer 200, and the first metal layer 201a is located on the adhesion layer 202. The adhesion layer 202 is used to enhance the bonding force between the interdigital electrode structure 201 and the piezoelectric layer 200.

[0056] In this embodiment, the material of the adhesion layer 202 includes titanium, titanium-tungsten alloy, nickel-chromium alloy or titanium nitride.

[0057] Please continue to refer to Figure 3 In this embodiment, the thickness of the first metal layer 201 a ranges from 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure 201 .

[0058] The wavelength of the acoustic wave excited by the interdigitated electrode structure 201 is the spacing dimension d between adjacent first electrode strips 2013 or adjacent second electrode strips 2014 along the second direction Y. The thickness of the first metal layer 201a is in the range of 3% to 10% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201. This thickness range can be used to build a large bandwidth and small size filtering device within a specific frequency range.

[0059] Please refer to Figure 5 , Figure 5 and Figure 4 In accordance with the viewing direction, a temperature compensation layer 203 is formed on the piezoelectric layer 200 , and the temperature compensation layer 203 covers the interdigital electrode structure 201 .

[0060] It should be noted that the temperature compensation layer 203 has the opposite temperature frequency shift characteristics to the piezoelectric layer 200, which can reduce the temperature coefficient of frequency (TCF) and tend to 0 ppm / r, thereby improving the characteristic of the operating frequency drift of the surface acoustic wave resonator 20 with the operating temperature, and having higher frequency-temperature stability. The surface acoustic wave resonator 20 including the temperature compensation layer 203 is called a temperature compensated surface acoustic wave resonator (i.e., TC-SAW resonator).

[0061] In this embodiment, the material of the temperature compensation layer 203 includes silicon dioxide, silicon oxyfluoride, silicon oxynitride or silicon oxycarbide.

[0062] In this embodiment, the thickness of the temperature compensation layer 203 is in the range of 15% to 40% of the wavelength of the acoustic wave excited by the interdigital electrode structure 201 .

[0063] Please continue to refer to Figure 5After forming the temperature compensation layer 203 , the method further includes: forming a frequency modulation layer 204 on the temperature compensation layer 203 .

[0064] In this embodiment, the material of the frequency modulation layer 204 includes silicon nitride, aluminum nitride, silicon oxynitride, aluminum oxide or silicon carbide.

[0065] Accordingly, a surface acoustic wave resonance device 20 is also provided in the embodiment of the present invention, please continue to refer to Figure 5 , including: a piezoelectric layer 200, the material of the piezoelectric layer 200 includes lithium niobate, and the crystal cutting angle of the piezoelectric layer 200 includes 165°~175°YX; an interdigitated electrode structure 201 located on the piezoelectric layer 200, the interdigitated electrode structure 201 includes at least a first metal layer 201a, and the material density of the first metal layer 201a is greater than 15,000 kilograms per cubic meter; a temperature compensation layer 203 located on the piezoelectric layer 200, and the temperature compensation layer 203 covers the interdigitated electrode structure 201.

[0066] The material of the piezoelectric layer 200 is lithium niobate with a crystal cut angle of 165° to 175° YX, which can obtain a larger electromechanical coupling coefficient (Kt) than lithium niobate with a crystal cut angle of 127° to 129° YX; in addition, the material density of the first metal layer 201a is greater than 15,000 kilograms per cubic meter. The first metal layer 201a can make the interdigital electrode structure 201 heavier, thereby reducing the acoustic wave velocity of the main resonant mode, reducing the chip size, and further increasing the electromechanical coupling coefficient (Kt), thereby realizing a large bandwidth and small size filtering device.

[0067] In this embodiment, the main mode excited by the interdigital electrode structure 201 is a transverse shear wave.

[0068] In this embodiment, the material of the first metal layer 201 a includes: tungsten, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0069] In this embodiment, the thickness of the first metal layer 201 a ranges from 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure 201 .

[0070] The wavelength of the acoustic wave excited by the interdigitated electrode structure 201 is the spacing dimension d between adjacent first electrode strips 2013 or adjacent second electrode strips 2014 along the second direction Y. The thickness of the first metal layer 201a is in the range of 3% to 10% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201. This thickness range can be used to build a large bandwidth and small size filtering device within a specific frequency range.

[0071] In this embodiment, the thickness of the temperature compensation layer 203 is in the range of 15% to 40% of the wavelength of the acoustic wave excited by the interdigital electrode structure 201 .

[0072] In this embodiment, the material of the temperature compensation layer 203 includes silicon dioxide, silicon oxyfluoride, silicon oxynitride or silicon oxycarbide.

[0073] Please continue to refer to Figure 3 In this embodiment, the interdigitated electrode structure 201 includes: a first bus 2011 and a second bus 2012 arranged in parallel along a first direction X; a plurality of first electrode strips 2013 connected to the first bus 2011, the plurality of first electrode strips 2013 are arranged in parallel along a second direction Y, the first direction X is perpendicular to the second direction Y; a plurality of second electrode strips 2014 connected to the second bus 2012, the plurality of second electrode strips 2014 are arranged in parallel along the second direction Y, the first electrode strips 2013 and the second electrode strips 2014 are staggered, and along the second direction Y the first electrode strips 2013 and the second electrode strips 2014 have an overlapping area.

[0074] In this embodiment, the surface acoustic wave resonator device 20 further includes: an adhesive layer 202 located on the piezoelectric layer 200 , and the first metal layer 201 a is located on the adhesive layer 202 .

[0075] In this embodiment, the material of the adhesion layer 202 includes titanium, titanium-tungsten alloy, nickel-chromium alloy or titanium nitride.

[0076] In this embodiment, the surface acoustic wave resonator 20 further includes a frequency modulation layer 204 located on the temperature compensation layer 203 .

[0077] In this embodiment, the material of the frequency modulation layer 204 includes silicon nitride, aluminum nitride, silicon oxynitride, aluminum oxide or silicon carbide.

[0078] Figure 6 FIG. 2 is a schematic structural diagram of a surface acoustic wave resonator device 20 in another embodiment of the present invention.

[0079] This embodiment is based on the above embodiment ( Figure 5 ) is further described on the basis of the surface acoustic wave resonance device 20, and the rest is the same as the above embodiment, except that: the interdigital electrode structure 201 is a double-layer structure. The following will be described in detail with reference to the accompanying drawings.

[0080] Please refer to Figure 6The interdigitated electrode structure 201 further includes: a second metal layer located on the first metal layer 201a, that is, the interdigitated electrode structure 201 includes: the first metal layer 201a, and the second metal layer 201b located on the first metal layer 201a.

[0081] In this embodiment, the material density of the first metal layer 201 a is greater than 15,000 kilograms per cubic meter.

[0082] In this embodiment, the material density of the first metal layer 201a is greater than the material density of the second metal layer 201b; the electrical conductivity of the second metal layer 201b is greater than the electrical conductivity of the first metal layer 201a. The material density of the first metal layer 201a is greater than the material density of the second metal layer 201b to ensure that the mass of the interdigital electrode structure 201 is increased, thereby reducing the acoustic velocity, increasing the electromechanical coupling coefficient (Kt), and being conducive to reducing the chip size. The second metal layer 201b has a higher electrical conductivity, which can improve the Q value and reduce the insertion loss.

[0083] In this embodiment, the material of the first metal layer 201 a includes: tungsten, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0084] In this embodiment, the material of the second metal layer 201 b includes at least one of aluminum, magnesium, silver, copper, titanium, beryllium and scandium.

[0085] In this embodiment, the thickness of the second metal layer 201 b is smaller than the thickness of the first metal layer 201 a .

[0086] Please continue to refer to Figure 3 In this embodiment, the thickness of the first metal layer 201a ranges from 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure 201. The wavelength of the acoustic wave excited by the interdigital electrode structure 201 is the spacing dimension d between adjacent first electrode strips 2013 or between adjacent second electrode strips 2014 along the second direction Y. The thickness of the first metal layer 201a ranges from 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure 201. This thickness range can be used to build a large bandwidth, small size filtering device within a specific frequency range.

[0087] Figure 7 FIG. 2 is a schematic structural diagram of a surface acoustic wave resonator device 20 in another embodiment of the present invention.

[0088] This embodiment is based on the above embodiment ( Figure 6) is further described on the basis of the surface acoustic wave resonance device 20, and the rest is the same as the above embodiment, except that: the interdigital electrode structure 201 is a three-layer structure. The following will be specifically described in conjunction with the accompanying drawings.

[0089] Please refer to Figure 7 The interdigitated electrode structure 201 also includes: a third metal layer 201c located on the second metal layer 201b, that is, the interdigitated electrode structure 201 includes: the first metal layer 201a, the second metal layer 201b located on the first metal layer 201a, and the third metal layer 201c located on the second metal layer 201b.

[0090] In this embodiment, the material density of the first metal layer 201 a is greater than 15,000 kilograms per cubic meter.

[0091] In this embodiment, the material density of the first metal layer 201a is greater than the material density of the second metal layer 201b; the yield strength of the material of the third metal layer 201c is greater than the yield strength of the material of the second metal layer 201b; the conductivity of the second metal layer 201b is greater than the conductivity of the first metal layer 201a, and the conductivity of the second metal layer 201b is greater than the conductivity of the third metal layer 201c. Among them, the material density of the first metal layer 201a is greater than the material density of the second metal layer 201b to ensure that the mass of the interdigitated electrode structure 201 is increased, thereby reducing the speed of sound, increasing the electromechanical coupling coefficient (Kt), and being conducive to reducing the chip size. The second metal layer 201b has a higher conductivity, which can improve the Q value and reduce the insertion loss. The third metal layer 201c has a higher yield strength, which can improve the power tolerance (reliability) of the device structure.

[0092] In this embodiment, the material of the first metal layer 201 a includes: tungsten, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0093] In this embodiment, the material of the second metal layer 201 b includes at least one of aluminum, magnesium, silver, copper, titanium, beryllium and scandium.

[0094] In this embodiment, the material of the third metal layer 201 c includes: titanium, molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

[0095] In this embodiment, the thickness of the second metal layer 201b is smaller than the thickness of the first metal layer 201a, and the thickness of the third metal layer 201c is smaller than the thickness of the first metal layer 201a.

[0096] Please continue to refer to Figure 3In this embodiment, the thickness of the first metal layer 201a ranges from 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure 201. The wavelength of the acoustic wave excited by the interdigital electrode structure 201 is the spacing dimension d between adjacent first electrode strips 2013 or between adjacent second electrode strips 2014 along the second direction Y. The thickness of the first metal layer 201a ranges from 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure 201. This thickness range can be used to build a large bandwidth, small size filtering device within a specific frequency range.

[0097] Figure 8 is a schematic structural diagram of a filtering device in an embodiment of the present invention; Fig. 9 It is a schematic structural diagram of a filtering device in another embodiment of the present invention.

[0098] Correspondingly, a filtering device 30 is also provided in the embodiment of the present invention, please continue to refer to Figures 5 to 7 , comprising a plurality of surface acoustic wave resonator devices 20 as described in any one of the above embodiments.

[0099] Since the material of the piezoelectric layer 200 in the surface acoustic wave resonator 20 adopts lithium niobate with a crystal cutting angle of 165° to 175°YX, a larger electromechanical coupling coefficient (Kt) can be obtained than that of lithium niobate with a crystal cutting angle of 127° to 129°YX; in addition, the material density of the first metal layer 201a is greater than 15,000 kilograms per cubic meter, and the first metal layer 201a can make the interdigitated electrode structure heavier, thereby reducing the acoustic wave velocity of the main resonant mode, reducing the chip size, and further increasing the electromechanical coupling coefficient (Kt), thereby realizing a large bandwidth and small size filtering device.

[0100] Please refer to Figure 8 And continue to combine reference Figures 5 to 7 The filtering device 30 includes: a transmitting filter 301, the transmitting filter 301 is used to transmit signals, the transmitting filter 301 includes multiple surface acoustic wave resonant devices 20, the multiple surface acoustic wave resonant devices 20 include multiple first transmitting series resonant devices TS1 and multiple first transmitting parallel resonant devices TT1; a receiving filter 302, the receiving filter 302 is used to receive signals, the receiving filter 302 includes at least one dual-mode surface acoustic wave filter device 21 and multiple surface acoustic wave resonant devices 20, the multiple surface acoustic wave resonant devices 20 include multiple first receiving series resonant devices RS1 and multiple first receiving parallel resonant devices RT1; wherein, the transmitting filter 301 is connected between the antenna terminal ANT and the transmitting terminal TX, the receiving filter 302 is connected between the antenna terminal ANT and the receiving terminal RX, and the operating frequency of the transmitting filter 301 is different from the operating frequency range of the receiving filter 302.

[0101] Please continue to refer to Figures 5 to 8 In one embodiment, when the operating frequency range of the transmitting filter 301 is 703 MHz to 748 MHz and the operating frequency range of the receiving filter 302 is 758 MHz to 803 MHz, the thickness range of the first metal layer 201a of each surface acoustic wave resonator device 20 in the transmitting filter 301 is 3% to 6% of the wavelength of the acoustic wave excited by the interdigital electrode structure 201; the thickness of the temperature compensation layer 203 of the first transmitting series resonance device TS1 is H TS1 The thickness of the temperature compensation layer 203 of the first transmitting parallel resonance device TT1 is H TT1 The thickness of the temperature compensation layer 203 of the first receiving series resonant device RS1 is H RS1 The thickness of the temperature compensation layer 203 of the first receiving parallel resonance device RT1 is H RT1 , then H TT1 >H TS1 =H RT1 >H RS1 ; The thickness range of the temperature compensation layer 203 of each of the surface acoustic wave resonator devices 20 in the transmitting filter 301 is 20% to 32% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201; the thickness range of the temperature compensation layer 203 of each of the surface acoustic wave resonator devices 20 in the receiving filter 302 is 28% to 38% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201.

[0102] Please continue to refer to Figures 5 to 8 In one embodiment, when the operating frequency range of the transmitting filter 301 is 663 MHz to 698 MHz and the operating frequency range of the receiving filter 302 is 617 MHz to 652 MHz, the thickness range of the first metal layer 201a of each of the surface acoustic wave resonator devices 20 in the transmitting filter 301 is 3% to 5% of the wavelength of the interdigital electrode structure 201; the thickness of the temperature compensation layer 203 of the first transmitting series resonant device TS1 is H TS1 The thickness of the temperature compensation layer 203 of the first transmitting parallel resonance device TT1 is H TT1 The thickness of the temperature compensation layer 203 of the first receiving series resonant device RS1 is H RS1 The thickness of the temperature compensation layer 203 of the first receiving parallel resonance device RT1 is H RT1 , then H RT1 >H RS1 =H TT1 >H TS1; The thickness range of the temperature compensation layer 203 of each of the surface acoustic wave resonator devices 20 in the transmitting filter 301 is 21% to 35% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201; the thickness range of the temperature compensation layer 203 of each of the surface acoustic wave resonator devices 20 in the receiving filter 302 is 19% to 28% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201.

[0103] Please refer to Fig. 9 The filtering device 30 includes at least one dual-mode surface acoustic wave filtering device 21 and a plurality of surface acoustic wave resonant devices 20 , and the plurality of surface acoustic wave resonant devices 20 include a plurality of series resonant devices 201 and a plurality of parallel resonant devices 202 .

[0104] Please continue to refer to Fig. 9 In one embodiment, when the operating frequency range of the filtering device 30 is 2496 MHz to 2690 MHz, the corresponding thickness range of the first metal layer 201a of each of the surface acoustic wave resonator devices 20 in the filtering device 30 is 4% to 8% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201; the thickness range of the temperature compensation layer 203 of each of the surface acoustic wave resonator devices 20 in the filtering device 30 is 20% to 38% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201.

[0105] Please continue to refer to Fig. 9 In one embodiment, when the operating frequency range of the filtering device 30 is 1427 MHz to 1517 MHz, the corresponding thickness range of the first metal layer 201a of each of the surface acoustic wave resonator devices 20 in the filtering device 30 is 3% to 6% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201; the thickness range of the temperature compensation layer 203 of each of the surface acoustic wave resonator devices 20 in the filtering device 30 is 15% to 30% of the wavelength of the acoustic wave excited by the interdigitated electrode structure 201.

[0106] It should be understood that the examples and embodiments herein are merely illustrative and that various modifications and corrections may be made by those skilled in the art without departing from the spirit and scope of the present invention as defined in this application and the appended claims.

Claims

1. A surface acoustic wave resonance device, characterized in that: include: A piezoelectric layer, wherein the material of the piezoelectric layer comprises lithium niobate, and the crystal cutting angle of the piezoelectric layer comprises 165° to 175° YX; an interdigitated electrode structure located on the piezoelectric layer, the interdigitated electrode structure comprising at least a first metal layer, the material density of the first metal layer being greater than 15,000 kilograms per cubic meter; A temperature compensation layer is located on the piezoelectric layer, and the temperature compensation layer covers the interdigital electrode structure.

2. The surface acoustic wave resonator device according to claim 1, characterized in that: The main mode excited by the interdigital electrode structure is a transverse shear wave.

3. The surface acoustic wave resonator device according to claim 1, characterized in that: The material of the first metal layer includes: tungsten, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

4. The surface acoustic wave resonator device according to claim 1, characterized in that: The interdigitated electrode structure further includes: a second metal layer located on the first metal layer.

5. The surface acoustic wave resonator device according to claim 4, characterized in that: The material density of the first metal layer is greater than the material density of the second metal layer; and the electrical conductivity of the second metal layer is greater than the electrical conductivity of the first metal layer.

6. The surface acoustic wave resonator device according to claim 5, characterized in that: The material of the second metal layer includes at least one of aluminum, magnesium, silver, copper, titanium, beryllium and scandium.

7. The surface acoustic wave resonator device according to claim 5, characterized in that: The interdigitated electrode structure further includes: a third metal layer located on the second metal layer.

8. The surface acoustic wave resonator device according to claim 7, characterized in that: The yield strength of the third metal layer material is greater than the yield strength of the second metal layer material; and the electrical conductivity of the second metal layer is greater than the electrical conductivity of the third metal layer.

9. The surface acoustic wave resonator device according to claim 8, characterized in that: The material of the third metal layer includes: titanium, molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold or hafnium.

10. The surface acoustic wave resonator device according to claim 7, characterized in that: The thickness of the second metal layer is smaller than that of the first metal layer; and the thickness of the third metal layer is smaller than that of the first metal layer.

11. The surface acoustic wave resonator device according to claim 1, characterized in that: The thickness of the first metal layer is in the range of 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure.

12. The surface acoustic wave resonator device according to claim 1, characterized in that: The thickness of the temperature compensation layer is in the range of 15% to 40% of the wavelength of the acoustic wave excited by the interdigital electrode structure.

13. The surface acoustic wave resonator device according to claim 1, characterized in that: The material of the temperature compensation layer includes silicon dioxide, silicon oxyfluoride, silicon oxynitride or silicon oxycarbide.

14. A method for forming a surface acoustic wave resonator device, characterized in that: include: Providing a piezoelectric layer, wherein the material of the piezoelectric layer comprises lithium niobate, and the crystal cutting angle of the piezoelectric layer comprises 165° to 175° YX; forming an interdigital electrode structure on the piezoelectric layer, wherein the interdigital electrode structure comprises at least a first metal layer, wherein the material density of the first metal layer is greater than 15,000 kilograms per cubic meter; A temperature compensation layer is formed on the piezoelectric layer, and the temperature compensation layer covers the interdigital electrode structure.

15. The method for forming a surface acoustic wave resonator device according to claim 14, wherein: The main mode excited by the interdigital electrode structure is a transverse shear wave.

16. The method for forming a surface acoustic wave resonator device according to claim 14, wherein: The interdigitated electrode structure further includes: a second metal layer located on the first metal layer.

17. The method for forming a surface acoustic wave resonator device according to claim 16, wherein: The material density of the first metal layer is greater than the material density of the second metal layer; and the electrical conductivity of the second metal layer is greater than the electrical conductivity of the first metal layer.

18. The method for forming a surface acoustic wave resonator device according to claim 17, wherein: The interdigitated electrode structure further includes: a third metal layer located on the second metal layer.

19. The method for forming a surface acoustic wave resonator device according to claim 18, wherein: The yield strength of the third metal layer material is greater than the yield strength of the second metal layer material; and the electrical conductivity of the second metal layer is greater than the electrical conductivity of the third metal layer.

20. The method for forming a surface acoustic wave resonator device according to claim 18, wherein: The thickness of the second metal layer is smaller than that of the first metal layer; and the thickness of the third metal layer is smaller than that of the first metal layer.

21. The method for forming a surface acoustic wave resonator device according to claim 14, wherein: The thickness of the first metal layer is in the range of 3% to 10% of the wavelength of the acoustic wave excited by the interdigital electrode structure.

22. The method for forming a surface acoustic wave resonator device according to claim 14, wherein: The thickness of the temperature compensation layer is in the range of 15% to 40% of the wavelength of the acoustic wave excited by the interdigital electrode structure.

23. A filtering device, characterized in that: The method comprises a plurality of surface acoustic wave resonator devices according to any one of claims 1 to 13.

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