CN116566355A - Elastic wave device, filtering device and multiplexing device - Google Patents
Elastic wave device, filtering device and multiplexing device Download PDFInfo
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- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000010897 surface acoustic wave method Methods 0.000 claims description 25
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 12
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- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02543—Characteristics of substrate, e.g. cutting angles
- H03H9/02559—Characteristics of substrate, e.g. cutting angles of lithium niobate or lithium-tantalate substrates
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02818—Means for compensation or elimination of undesirable effects
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02818—Means for compensation or elimination of undesirable effects
- H03H9/02929—Means for compensation or elimination of undesirable effects of ageing changes of characteristics, e.g. electro-acousto-migration
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/05—Holders; Supports
- H03H9/08—Holders with means for regulating temperature
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
- H03H9/14544—Transducers of particular shape or position
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/25—Constructional features of resonators using surface acoustic waves
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezo-electric or electrostrictive material
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
- H03H9/6489—Compensation of undesirable effects
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
- H03H9/72—Networks using surface acoustic waves
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
An elastic wave device, a filtering device and a multiplexing device, the elastic wave device comprising: the material of the substrate comprises lithium niobate, and the crystal chamfer comprises 130-140 YX; an interdigital transducer on a substrate, the interdigital transducer comprising a plurality of interdigital electrodes alternately arranged along a first direction parallel to the surface of the substrate, the interdigital electrodes comprising at least a first metal layer, the density of the material of the first metal layer being greater than 15000 kilograms per cubic meter; a temperature compensation layer on the substrate and on the interdigital transducer; and the frequency modulation layer is positioned on the temperature compensation layer. The performance of the elastic wave device is improved.
Description
Technical Field
The present invention relates to the field of filters, and in particular, to an elastic wave device, a filtering device, and a multiplexing device.
Background
A Radio Frequency (RF) front-end chip of a wireless communication device includes a power amplifier, an antenna switch, a Radio Frequency filter, a multiplexer, a low noise amplifier, and the like. The radio frequency filter includes a piezoelectric surface acoustic wave (Surface Acoustic Wave, SAW for short), a piezoelectric bulk acoustic wave (Bulk Acoustic Wave, BAW for short), a Micro-Electro-Mechanical System (MEMS for short), an integrated passive device (Integrated Passive Devices, IPD for short), and the like.
The SAW resonator has a high quality factor (Q value), and is manufactured into an RF filter with low insertion loss (insertion loss) and high out-band rejection (out-band rejection), that is, a SAW filter, which is a mainstream RF filter currently used in wireless communication devices such as mobile phones and base stations. SAW resonators have a negative temperature coefficient of frequency (Temperature Coefficient of Frequency, TCF), i.e. the resonant frequency (resonant frequency) of the resonator decreases when the temperature increases and increases when the temperature decreases. The reliability and stability of SAW filters are reduced. In order to improve the characteristic of the resonance frequency drift of the SAW resonator with the operating temperature, a temperature compensation layer is added on the piezoelectric substrate, and the temperature compensation layer has a frequency temperature coefficient opposite to that of the piezoelectric substrate. The combination of the two leads the temperature coefficient of the frequency of the whole resonator to trend to zero, thereby improving the reliability and the stability of the filter. Such a SAW resonator including a temperature compensation layer is called a temperature compensation SAW (Temperature Compensated SAW, TC-SAW) resonator, and a filter composed of the TC-SAW resonator is called a TC-SAW filter.
However, the performance of existing TC-SAW filters remains to be improved.
Disclosure of Invention
The invention solves the technical problem of providing an elastic wave device, a filtering device and a multiplexing device so as to improve the performance of the traditional TC-SAW filter.
In order to solve the above technical problems, the present invention provides an elastic wave device, including: the material of the substrate comprises lithium niobate, and the crystal chamfer comprises 130-140 YX; one or more interdigital transducers on a substrate, the interdigital transducers comprising a plurality of interdigital electrodes alternately arranged along a first direction parallel to the surface of the substrate, the interdigital electrodes comprising at least a first metal layer having a density of material greater than 15000 kilograms per cubic meter; a temperature compensation layer on the substrate and on the interdigital transducer.
Optionally, the material of the first metal layer includes tungsten, platinum, rhenium, osmium, iridium, tantalum, gold, or hafnium.
Optionally, the interdigital electrode further includes: and a second metal layer on the first metal layer.
Optionally, the density of the first metal layer is greater than the density of the second metal layer; the second metal layer has a conductivity greater than the conductivity of the first metal layer.
Optionally, the material of the second metal layer includes one or a combination of two of aluminum, magnesium, silver, copper, titanium, beryllium, and scandium.
Optionally, the interdigital electrode further includes: and a third metal layer on the second metal layer.
Optionally, the grain diameter of the third metal layer material is larger than the grain diameter of the second metal layer material; the second metal layer has a conductivity greater than the third metal layer.
Optionally, the material of the third metal layer includes titanium, molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold, or hafnium.
Optionally, the thickness of the second metal layer is smaller than the thickness of the first metal layer; the thickness of the third metal layer is smaller than that of the first metal layer.
Optionally, the thickness of the first metal layer ranges from 3% to 6% of the wavelength of the interdigital transducer.
Optionally, the thickness range of the temperature compensation layer is 20% -50% of the wavelength of the interdigital transducer.
Correspondingly, the technical scheme of the invention also provides a filtering device, which comprises: the one or more first elastic wave devices as described above, wherein the first elastic wave devices comprise surface acoustic wave resonators.
Optionally, the plurality of first elastic wave devices includes a first series elastic wave device and a first parallel elastic wave device.
Optionally, the working frequency range of the filtering device is 703 MHz-748 MHz.
Optionally, the thickness range of the first metal layer of the interdigital transducer of the first elastic wave device is 3% -6% of the wavelength of the interdigital transducer; the thickness of the temperature compensation layer of the parallel elastic wave device is larger than that of the temperature compensation layer of the serial elastic wave device.
Optionally, the thickness range of the temperature compensation layer of the first parallel elastic wave device is 25% -50% of the wavelength of the interdigital transducer of the first parallel elastic wave device; the thickness range of the temperature compensation layer of the first series elastic wave device is 25% -45% of the wavelength of the interdigital transducer of the first series elastic wave device.
Correspondingly, the technical scheme of the invention also provides a filtering device, which comprises: the one or more second elastic wave devices as described above, wherein the second elastic wave device comprises a surface acoustic wave resonator or a dual-mode surface acoustic wave filter.
Optionally, the working frequency range of the filtering device is 758 MHz-803 MHz.
Optionally, the plurality of second elastic wave devices includes a second series elastic wave device and a second parallel elastic wave device.
Optionally, the thickness range of the first metal layer of the interdigital transducer of the second elastic wave device is 3% -6% of the wavelength of the interdigital transducer; the thickness range of the temperature compensation layer of the parallel elastic wave device is larger than or equal to that of the temperature compensation layer of the serial elastic wave device.
Optionally, the thickness range of the temperature compensation layer of the second parallel elastic wave device is 25% -45% of the wavelength of the interdigital transducer of the second parallel elastic wave device; the thickness range of the temperature compensation layer corresponding to the second series elastic wave device is 20% -40% of the wavelength of the interdigital transducer of the second series elastic wave device.
Correspondingly, the technical scheme of the invention also provides a multiplexing device, which comprises: the first filtering device; and a second filtering means including a ladder filter or a dual mode surface acoustic wave filter.
Optionally, the first filtering device is a transmitting end filter, and the second filtering device is a receiving end filter.
Correspondingly, the technical scheme of the invention also provides a multiplexing device, which comprises: a third filtering means comprising a ladder filter; and the fourth filtering device.
Optionally, the third filtering device is a transmitting end filter, and the fourth filtering device is a receiving end filter.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
according to the technical scheme, the interdigital electrode at least comprises a first metal layer, and the density of the material of the first metal layer is larger than 15000 kilograms per cubic meter. The interdigital electrode can be weighted by adjusting the thickness and the materials of each metal layer, so that the sound wave speed of a main resonance mode is reduced, the electromechanical coupling coefficient is increased, and the chip size is reduced.
Further, the material of the substrate comprises lithium niobate, and the crystal cut angle comprises 130-140 YX. The piezoelectric substrate comprises 130-140 degrees YX-LiNbO 3 The coupling of the transverse shear wave can be reduced, so that the coupling of the transverse shear wave enhanced by the interdigital electrode formed by multiple metal layers is relieved, and the problem of poor filter performance is solved.
Further, the density of the first metal layer is larger than that of the second metal layer, and the density of the first metal layer is larger, so that the interdigital electrode becomes heavy, the sound wave speed of a main resonance mode is reduced, the electromechanical coupling coefficient is increased, and the chip size is reduced.
Further, the conductivity of the second metal layer is larger than that of the first metal layer, and the conductivity of the second metal layer is larger than that of the third metal layer, so that the series quality factor of the resonator can be improved, and the effect of reducing the insertion loss of the filter is achieved.
Further, the grain diameter of the third metal layer material is larger than that of the second metal layer material, so that electromigration of the metal surface of the second metal layer can be inhibited, and tolerance (reliability) of the device under high power is improved.
Further, the thickness of the second metal layer is less than the thickness of the first metal layer; the thickness of the third metal layer is smaller than the thickness of the first metal layer. The density of the first metal layer at the bottommost layer is larger, the thickness of the first metal layer at the bottommost layer is thicker (larger than the thickness of the second metal layer and the thickness of the third metal layer), and the first metal layer at the bottommost layer enables the interdigital electrode to be heavier, so that the sound wave speed of a main resonance mode is reduced, the electromechanical coupling coefficient is increased, and the chip size is reduced.
According to the filtering device, the interdigital electrode of the interdigital transducer at least comprises a first metal layer. The interdigital electrode can be weighted by adjusting the thickness and the material of each metal layer, so that the sound wave speed of a main resonance mode is reduced, the electromechanical coupling coefficient is increased, and the reduction of the wave speed can improve the performance in a filter Band for a filter or a duplexer of a wireless communication frequency Band (e.g. Band 28) with lower frequency, such as increasing the bandwidth, reducing the insertion loss, improving the standing wave ratio and the like.
Drawings
FIG. 1 is a schematic diagram of a SAW resonator in an embodiment;
FIGS. 2 and 3 are schematic views showing the structure of an elastic wave device according to an embodiment of the present invention;
FIG. 4 is a graph showing the relationship between crystal cut angle and clutter distribution according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a multiplexing device according to an embodiment of the invention.
Detailed Description
As described in the background, TC-SAW filter performance is still to be improved. The analysis will now be described with reference to specific examples.
Fig. 1 is a schematic structural diagram of a surface acoustic wave resonator in an embodiment.
Referring to fig. 1, the surface acoustic wave resonator includes: a substrate 100; an interdigital transducer on the substrate 100, the interdigital transducer comprising a plurality of interdigital electrodes alternately arranged along a first direction parallel to the surface of the substrate, the interdigital electrodes comprising a first metal layer 101 and a second metal layer 102 on the first metal layer 101; a temperature compensation layer 103 on the substrate 100 and on the interdigital transducer; a frequency modulation layer 104 on the temperature compensation layer 103.
The acoustic surface wave resonator has a small electromechanical coupling coefficient of about 10%; the wave speed is fast, about 3500m/s. In order to reduce the chip size, a resonator electrode structure with a larger electromechanical coupling coefficient and a slower wave speed is required for a filter and a duplexer in a lower frequency band (500 MHz to 1000 MHz).
In order to solve the above problems, the technical solution of the present invention provides an elastic wave device, a filtering device and a multiplexing device, where the interdigital electrode at least includes a first metal layer, and the density of the material of the first metal layer is greater than 15000 kg per cubic meter. The thickness and the materials of each metal layer can be adjusted to enable the interdigital electrode to be heavy, so that the sound wave speed of a main resonance mode is reduced, the electromechanical coupling coefficient is increased, and the chip size is reduced.
In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.
Fig. 2 and 3 are schematic structural views of an elastic wave device according to an embodiment of the present invention.
Referring to fig. 2 and 3, fig. 3 is a top view of fig. 2 with the temperature compensation layer and the frequency modulation layer omitted, fig. 2 is a schematic structural diagram of fig. 3 along a section line AA1, and the elastic wave device includes: a substrate 200; one or more interdigital transducers on the substrate 200, the interdigital transducers comprising a plurality of interdigital electrodes alternately arranged along a first direction parallel to the surface of the substrate 200, the interdigital electrodes comprising at least a first metal layer 201, the density of the material of the first metal layer 201 being greater than 15000 kilograms per cubic meter; a temperature compensation layer 204 on the substrate 200 and on the interdigital transducer; a frequency modulation layer 205 located on the temperature compensation layer 204.
The material of the substrate 200 comprises a piezoelectric material. In this embodiment, the piezoelectric material includes lithium niobate, and the crystal cut angle includes 130 ° to 140 ° YX (YX-LiNbO) 3 )。
In this embodiment, the interdigital electrode further includes: a second metal layer 202 on the first metal layer 201; a third metal layer 203 located on the second metal layer 202.
Referring to fig. 4, fig. 4 is a schematic diagram showing a relationship between a crystal cut angle and an electromechanical Coupling coefficient according to an embodiment of the present invention, wherein an abscissa in fig. 4 is a crystal cut angle (cut angle) and an ordinate is an electromechanical Coupling coefficient (Coupling Factor). The curve with smaller ordinate corresponds to a transverse shear (Shear Horizontal Wave, abbreviated as SH) wave, the curve with larger ordinate corresponds to a main resonance mode Rayleigh wave (Rayleigh wave), the SH wave is a parasitic mode, and can degrade the performance of the resonator, specifically, the SH wave usually occurs in a region where the series resonator and the parallel resonator are connected, so that a downward concave portion occurs in a passband region of an insertion loss curve of the filter, and the insertion loss of the resonator is increased.
In this embodiment, the piezoelectric material includes lithium niobate, and the crystal cut angle includes 130 ° to 140 ° YX, and referring to fig. 4, it can be seen that the crystal cut angle (cut angle) in the range of 130 ° to 140 ° can reduce the coupling of the transverse shear wave SH, thereby alleviating the coupling of the transverse shear wave SH enhanced by the interdigital electrode formed by the multiple metal layers (the first metal layer 201, the second metal layer 202 and), and further solving the problem of deteriorating the resonator performance.
In this embodiment, the density of the material of the first metal layer 201 is greater than 15000 kilograms per cubic meter.
In this embodiment, the density of the first metal layer 201 is greater than the density of the second metal layer 202; the conductivity of the second metal layer 202 is greater than the conductivity of the first metal layer 201; the grain diameter of the material of the third metal layer 203 is larger than that of the material of the second metal layer 202; the second metal layer 202 has a conductivity greater than the third metal layer 203.
The density of the first metal layer 201 is greater than that of the second metal layer 202, and the density of the first metal layer 201 is greater, so that the interdigital electrode becomes heavy, thereby reducing the sound wave velocity of the main resonance mode, increasing the electromechanical coupling coefficient, and being beneficial to reducing the chip size.
The conductivity of the second metal layer 202 is greater than that of the first metal layer 201, and the conductivity of the second metal layer 202 is greater than that of the third metal layer 203, so that the series quality factor of the resonator can be improved, and the effect of reducing the insertion loss of the filter is achieved.
The grain diameter of the third metal layer 203 material is larger than that of the second metal layer 202 material, and the grain diameter of the third metal layer 203 material is larger, so that electromigration of the metal surface of the second metal layer 202 can be inhibited, and the tolerance (reliability) of the device under high power is improved.
In this embodiment, the material of the first metal layer 201 includes tungsten, platinum, rhenium, osmium, iridium, tantalum, gold, or hafnium.
In this embodiment, the material of the second metal layer 202 includes one or a combination of two of aluminum, magnesium, silver, copper, titanium, beryllium, and scandium.
In this embodiment, the material of the third metal layer 203 includes titanium, molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold, or hafnium.
In this embodiment, the thickness of the second metal layer 202 is smaller than the thickness of the first metal layer 201; the thickness of the third metal layer 203 is smaller than the thickness of the first metal layer 201.
The first metal layer 201 at the bottommost layer has a larger density, and the thickness of the first metal layer 201 at the bottommost layer is thicker (greater than the thickness of the second metal layer 202 and the thickness of the third metal layer 203), so that the interdigital electrode is heavier by the first metal layer 201 at the bottommost layer, thereby reducing the acoustic wave velocity of the main resonance mode, increasing the electromechanical coupling coefficient, and being beneficial to reducing the chip size. In addition, the thicknesses of the third metal layer 203 and the second metal layer 202 are small, so that the processes of the third metal layer and the second metal layer in forming are simple and easy to manufacture.
In this embodiment, the thickness of the first metal layer 201 ranges from 7% to 13% of the wavelength of the interdigital transducer.
In this embodiment, the material of the temperature compensation layer 204 includes silicon dioxide or silicon oxyfluoride.
In this embodiment, the thickness of the temperature compensation layer 204 ranges from 20% to 70% of the interdigital transducer wavelength.
It should be noted that, in the case where the elastic wave device includes a plurality of interdigital transducers, the wavelengths of the interdigital transducers may be different. The thickness of the temperature compensation layer 204 corresponding to the interdigital transducer ranges from 20% to 70% of the wavelength of the interdigital transducer, the thickness of the temperature compensation layer 204 corresponding to each interdigital transducer is the same, and the thickness of the temperature compensation layer 204 corresponding to each interdigital transducer ranges from 20% to 70% of the wavelength of the interdigital transducer. In another embodiment, the thickness of the corresponding temperature compensation layer 204 on each interdigital transducer is different, and the thickness of the corresponding temperature compensation layer 204 on each interdigital transducer is in the range of 20% to 70% of the interdigital transducer wavelength.
The thickness range of the first metal layer 201 and the thickness range of the temperature compensation layer 204 are optimized thicknesses, so that better resonator performance can be obtained.
In this embodiment, the material of the frequency modulation layer 205 includes silicon nitride, aluminum oxynitride, aluminum oxide, or silicon carbide.
In another embodiment, the interdigital electrode comprises: a first metal layer, the first metal layer material having a density greater than 15000 kilograms per cubic meter.
In yet another embodiment, the interdigital electrode comprises: a first metal layer and a second metal layer on the first metal layer, the first metal layer material having a density of greater than 15000 kilograms per cubic meter; the density of the first metal layer is greater than the density of the second metal layer; the second metal layer has a conductivity greater than the first metal layer.
With continued reference to fig. 2 and 3, in this embodiment, the method further includes: an adhesion layer 206 between the interdigitated electrodes and the substrate 200.
In this embodiment, the material of the adhesion layer 206 includes titanium, titanium tungsten alloy, nickel chromium alloy, or titanium nitride.
The adhesion layer 206 serves to enhance the bonding force between the interdigital electrode and the substrate 200.
Accordingly, the embodiment of the present invention further provides a method for forming the elastic wave device as described in fig. 2, 3 and 4, including:
providing a substrate 200, wherein the material of the substrate 200 comprises lithium niobate, and the crystal cut angle comprises 130-140 YX;
forming one or more interdigital transducers on the substrate 200, the interdigital transducers comprising a plurality of interdigital electrodes alternately arranged along a first direction parallel to the surface of the substrate 200, the interdigital electrodes comprising at least a first metal layer 201, the density of the material of the first metal layer 201 being greater than 15000 kilograms per cubic meter;
forming a temperature compensation layer 204 on the substrate and on the interdigital transducer;
a frequency modulation layer 205 is formed on the temperature compensation layer 204.
The forming method of the interdigital transducer comprises the following steps: forming an electrode material layer (not shown) on the substrate 200; and patterning the electrode material layer to form the interdigital transducer.
Correspondingly, the embodiment of the invention also provides a first filtering device, which comprises: a plurality of first acoustic wave devices as described in fig. 2, 3 and 4, wherein the first acoustic wave devices comprise surface acoustic wave resonators.
In this embodiment, the plurality of first elastic wave devices includes a first series elastic wave device and a first parallel elastic wave device.
In this embodiment, the operating frequency range of the filtering device is 703MHz to 748MHz.
In this embodiment, the thickness of the first metal layer of the interdigital transducer of the first elastic wave device ranges from 3% to 6% of the wavelength of the interdigital transducer.
The thickness of the temperature compensation layer of the first parallel elastic wave device is larger than that of the temperature compensation layer of the first series elastic wave device.
In this embodiment, the thickness range of the temperature compensation layer of the first parallel elastic wave device is 25% -50% of the wavelength of the interdigital transducer of the first parallel elastic wave device; the thickness range of the temperature compensation layer of the first series elastic wave device is 25% -45% of the wavelength of the interdigital transducer of the first series elastic wave device.
It should be noted that, in the case where each of the plurality of first elastic wave devices includes a plurality of interdigital transducers, the wavelengths of the interdigital transducers of each of the first elastic wave devices may also be different.
Correspondingly, the embodiment of the invention also provides a fourth filtering device, which comprises: one or more second elastic wave devices as described in fig. 2, 3 and 4, wherein the second elastic wave devices comprise a surface acoustic wave resonator or a dual-mode surface acoustic wave filter.
In this embodiment, the operating frequency range of the filtering device is 758MHz to 803MHz.
In this embodiment, the plurality of second elastic wave devices includes a second series elastic wave device and a second parallel elastic wave device.
In this embodiment, the thickness of the first metal layer of the interdigital transducer of the second elastic wave device ranges from 3% to 6% of the wavelength of the interdigital transducer.
The thickness range of the temperature compensation layer of the second parallel elastic wave device is larger than or equal to that of the temperature compensation layer of the second series elastic wave device.
In this embodiment, the thickness range of the temperature compensation layer of the second parallel elastic wave device is 25% -45% of the wavelength of the interdigital transducer of the second parallel elastic wave device; the thickness range of the temperature compensation layer of the second series elastic wave device is 20% -40% of the wavelength of the interdigital transducer of the second series elastic wave device.
It should be noted that, in the case where each of the plurality of second elastic wave devices includes a plurality of interdigital transducers, the wavelengths of the interdigital transducers of each of the second elastic wave devices may also be different.
Fig. 5 is a schematic structural diagram of a multiplexing device according to an embodiment of the invention.
Referring to fig. 5 in conjunction with fig. 2, 3 and 4, fig. 5 is a top view of a multiplexing device, fig. 3 is an enlarged schematic view of a single elastic wave device, and fig. 2 is a schematic cross-sectional structure of the single elastic wave device along a cross-sectional line AA1 in fig. 3, in this embodiment, the multiplexing device includes: a first filtering means TX comprising a plurality of first elastic wave means as described in fig. 2, 3 and 4, wherein the first elastic wave means comprises a surface acoustic wave resonator; fourth filter means RX comprising one or more second elastic wave means as described in fig. 2, 3 and 4, wherein said second elastic wave means comprises a surface acoustic wave resonator or a dual mode surface acoustic wave filter.
The first filtering device TX is a transmitting end filter, and the fourth filtering device RX is a receiving end filter.
The first filtering means TX comprise: the specific description of the first filtering device TX is described above for the first filtering device, and is not repeated here.
The fourth filtering device RX includes: one or more of the second elastic wave devices shown in fig. 2, 3 and 4, and the detailed description of the fourth filter device RX is described above for the fourth filter device, which is not repeated here.
In this embodiment, the operating frequency range of the first filter TX is 703MHz to 748MHz; the working frequency range of the second filter RX is 758 MHz-803 MHz. The first filter TX is a transmitting end filter of the Band28 duplexer, and the second filter RX is a receiving end filter of the Band28 duplexer.
The first elastic wave device comprises a first serial elastic wave device TS1 and a first parallel elastic wave device TT1; the second elastic wave device comprises a second series elastic wave device RS2 and a second parallel elastic wave device RT2.
In this embodiment, the thickness of the temperature compensation layer of the first parallel elastic wave device TT1 is a first thickness, the thickness of the temperature compensation layer of the second serial elastic wave device RS2 is a second thickness, the thickness of the temperature compensation layers of the first serial elastic wave device TS1 and the second parallel elastic wave device RT2 is a third thickness, the first thickness is greater than the third thickness, and the third thickness is greater than or equal to the second thickness.
The interdigital electrodes of the interdigital transducer comprise at least a first metal layer 201, the first metal layer 201 having a material density of greater than 15000 kilograms per cubic meter (as illustrated in fig. 2 and 3). The interdigital electrode can be heavier by adjusting the thickness and the materials of each metal layer, so that the sound wave speed of a main resonance mode is reduced, and the electromechanical coupling coefficient is increased; reducing the wave speed may improve the performance in the filter band for low frequency filters or diplexers, such as increasing bandwidth, reducing insertion loss, improving standing wave ratio, etc.
In another embodiment, the multiplexing device comprises: a first filtering means TX comprising one or more first elastic wave means as described in fig. 2, 3 and 4, wherein the first elastic wave means comprises a surface acoustic wave resonator; and the second filtering device comprises a ladder filter or a dual-mode surface acoustic wave filter.
The first filtering device TX is a transmitting end filter, and the second filtering device TX is a receiving end filter.
The first filtering means TX comprise: one or more of the first elastic wave devices as described in fig. 2, 3 and 4, and the specific description of the first filtering device TX is described above for the first filtering device, and will not be repeated here.
In another embodiment, the multiplexing device comprises: a third filtering means comprising a ladder filter; and fourth filtering means RX comprising: one or more second elastic wave devices as described in fig. 2, 3 and 4, wherein the second elastic wave devices comprise a surface acoustic wave resonator or a dual-mode surface acoustic wave filter.
The third filter device is a transmitting end filter, and the fourth filter device RX is a receiving end filter.
The fourth filtering device RX includes: one or more of the second elastic wave devices shown in fig. 2, 3 and 4, and the detailed description of the fourth filter device RX is described above for the fourth filter device, which is not repeated here.
Accordingly, an embodiment of the present invention further provides a method for forming a multiplexing device as described in fig. 5, including:
forming a first filtering device TX comprising a plurality of first elastic wave devices as described in fig. 2, 3 and 4, wherein the first elastic wave devices comprise surface acoustic wave resonators;
forming a fourth filter means RX comprising: one or more second elastic wave devices as described in fig. 2, 3 and 4, wherein the second elastic wave devices comprise a surface acoustic wave resonator or a dual-mode surface acoustic wave filter.
An antenna end is formed, which is connected between the first filtering means TX and the fourth filtering means RX.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.
Claims (25)
1. An elastic wave device, comprising:
the material of the substrate comprises lithium niobate, and the crystal chamfer comprises 130-140 YX;
one or more interdigital transducers on the substrate, the interdigital transducers comprising a plurality of interdigital electrodes alternately arranged along a first direction parallel to the surface of the substrate, the interdigital electrodes comprising at least a first metal layer, the first metal layer having a material density of greater than 15000 kilograms per cubic meter of metal layer;
a temperature compensation layer on the substrate and on the interdigital transducer.
2. The elastic wave device of claim 1, wherein the material of the first metal layer comprises tungsten, platinum, rhenium, osmium, iridium, tantalum, gold, or hafnium.
3. The elastic wave device of claim 1, wherein the interdigital electrode further comprises: and a second metal layer on the first metal layer.
4. The elastic wave device of claim 3, wherein a density of the first metal layer is greater than a density of the second metal layer; the second metal layer has a conductivity greater than the first metal layer.
5. The elastic wave device of claim 4, wherein the material of the second metal layer comprises one or a combination of two of aluminum, magnesium, silver, copper, titanium, beryllium, and scandium.
6. The elastic wave device of claim 4, wherein the interdigital electrode further comprises: and a third metal layer on the second metal layer.
7. The elastic wave device of claim 6, wherein a grain diameter of the third metal layer material is larger than a grain diameter of the second metal layer material; the second metal layer has a conductivity greater than the third metal layer.
8. The elastic wave device of claim 7, wherein the material of the third metal layer comprises titanium, molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold, or hafnium.
9. The elastic wave device of claim 6, wherein a thickness of the second metal layer is less than a thickness of the first metal layer; the thickness of the third metal layer is smaller than the thickness of the first metal layer.
10. The acoustic wave device of claim 1, wherein the thickness of the first metal layer ranges from 3% to 6% of the interdigital transducer wavelength.
11. The elastic wave device of claim 1, wherein the temperature compensation layer has a thickness in the range of 20% to 50% of the interdigital transducer wavelength.
12. A filtering apparatus, comprising:
a plurality of first elastic wave devices according to any one of claims 1 to 9, wherein the first elastic wave devices comprise surface acoustic wave resonators.
13. The filter apparatus of claim 12 wherein a plurality of said first elastic wave devices comprise a first series elastic wave device and a first parallel elastic wave device.
14. The filter device of claim 13, wherein the filter device has an operating frequency in the range of 703MHz to 748MHz.
15. The filtering device of claim 14, wherein the thickness of the first metal layer of the interdigital transducer of the first elastic wave device ranges from 3% to 6% of the wavelength of the interdigital transducer; the thickness of the temperature compensation layer of the parallel elastic wave device is larger than that of the temperature compensation layer of the serial elastic wave device.
16. The filtering device of claim 15, wherein the temperature compensation layer of the first parallel elastic wave device has a thickness in the range of 25% to 50% of the interdigital transducer wavelength of the first parallel elastic wave device; the thickness range of the temperature compensation layer of the first series elastic wave device is 25% -45% of the wavelength of the interdigital transducer of the first series elastic wave device.
17. A filtering apparatus, comprising:
the one or more second elastic wave devices according to any one of claims 1 to 9, wherein the second elastic wave device comprises a surface acoustic wave resonator or a dual-mode surface acoustic wave filter.
18. The filter device of claim 17, wherein the filter device has an operating frequency in the range of 758MHz to 803MHz.
19. The filter apparatus of claim 18 wherein a plurality of said second elastic wave devices comprise a second series elastic wave device and a second parallel elastic wave device.
20. The filtering device of claim 19, wherein the thickness of the first metal layer of the interdigital transducer of the second elastic wave device ranges from 3% to 6% of the wavelength of the interdigital transducer; the thickness range of the temperature compensation layer of the parallel elastic wave device is larger than or equal to that of the temperature compensation layer of the serial elastic wave device.
21. The filtering device of claim 20, wherein the temperature compensation layer thickness of the second parallel elastic wave device ranges from 25% to 45% of the interdigital transducer wavelength of the second parallel elastic wave device; the temperature compensation layer thickness range corresponding to the second series elastic wave device is 20% -40% of the interdigital transducer wavelength of the second series elastic wave device.
22. A multiplexing device, comprising:
a first filtering means as claimed in any one of claims 12 to 16; and
and the second filtering device comprises a ladder filter or a dual-mode surface acoustic wave filter.
23. The multiplexing device of claim 22 wherein the first filtering means is a transmit side filter and the second filtering means is a receive side filter.
24. A multiplexing device, comprising:
a third filtering means comprising a ladder filter; and
a fourth filtering device as claimed in any one of claims 17 to 21.
25. The multiplexing device of claim 24 wherein the third filtering means is a transmit side filter and the fourth filtering means is a receive side filter.
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| CN202310388001.7A CN116566355A (en) | 2023-04-12 | 2023-04-12 | Elastic wave device, filtering device and multiplexing device |
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