WO2018163842A1 - 弾性波装置、高周波フロントエンド回路及び通信装置 - Google Patents
弾性波装置、高周波フロントエンド回路及び通信装置 Download PDFInfo
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- 238000004891 communication Methods 0.000 title claims description 14
- 239000000463 material Substances 0.000 claims abstract description 96
- 239000013078 crystal Substances 0.000 claims description 50
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- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 claims description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 13
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 13
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- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
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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
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02543—Characteristics of substrate, e.g. cutting angles
- H03H9/02574—Characteristics of substrate, e.g. cutting angles of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate
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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
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
- H03H9/6489—Compensation of undesirable effects
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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
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02818—Means for compensation or elimination of undesirable effects
- H03H9/02866—Means for compensation or elimination of undesirable effects of bulk wave excitation and reflections
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- 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
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- H03H9/02834—Means for compensation or elimination of undesirable effects of temperature influence
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- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/005—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
- H04B1/0053—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges with common antenna for more than one band
- H04B1/0057—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges with common antenna for more than one band using diplexing or multiplexing filters for selecting the desired band
Definitions
- the present invention relates to an acoustic wave device, a high-frequency front-end circuit having the acoustic wave device, and a communication device.
- a piezoelectric body made of LiTaO 3 is laminated on a silicon substrate via a SiO 2 film.
- a piezoelectric body made of LiTaO 3 is laminated on a (111) plane, a (100) plane, or a (110) plane of silicon via a SiO 2 film.
- An object of the present invention is to provide an elastic wave device capable of suppressing higher-order modes while maintaining good characteristics of the main mode, and a high-frequency front-end circuit and a communication device having the elastic wave device. .
- the Euler angles (phi 1, theta 1, [psi 1) has, the Euler angles (phi 1, theta 1, [psi 1) elastic constant in the following formula (1)
- ⁇ and ⁇ are as follows.
- l 1 to l 3 , m 1 to m 3, and n 1 to n 3 in ⁇ and ⁇ are as follows.
- At least a part of the higher-order mode excited by the IDT electrode propagates through both the material layer and the piezoelectric body.
- the material layer is a high sound velocity material in which the sound velocity of the bulk wave is higher than the sound velocity of the elastic wave propagating through the piezoelectric body.
- the thickness of the piezoelectric body is 10 ⁇ or less. In this case, the higher-order mode response can be more effectively suppressed.
- the absolute value of the C 56 of the material layer is not less than 8.4GPa. In this case, the higher order mode can be more effectively suppressed.
- the absolute value of the C 56 of the material layer is less than 28 GPa. In this case, the deterioration of characteristics due to the main mode to be used hardly occurs.
- the material layer is made of a single crystal.
- the single crystal constituting the material layer is made of a single crystal other than a piezoelectric body. In that case, further higher-order modes are unlikely to occur in the material layer. The main mode can be confined by the material layer, and good characteristics can be obtained.
- the thickness of the piezoelectric body is 3.5 ⁇ or less.
- the thickness of the piezoelectric body is 2.5 ⁇ or less.
- the thickness of the piezoelectric body is 1.5 ⁇ or less.
- the thickness of the piezoelectric body is 0.5 ⁇ or less.
- the acoustic wave of the bulk wave that is provided between the material layer and the piezoelectric body is propagated through the piezoelectric body.
- a low sound velocity membrane that is slower than the sound velocity is further provided.
- the low sound velocity film is a silicon oxide film. In this case, the frequency temperature characteristic can be improved.
- the thickness of the low sound velocity film is 2 ⁇ or less.
- the single crystal constituting the material layer is made of silicon. In this case, the higher order mode can be more effectively suppressed.
- the piezoelectric body is made of lithium tantalate.
- the higher-order mode can be suppressed and the electromechanical coupling coefficient can be easily adjusted by adjusting the crystal orientation.
- the acoustic wave of the bulk wave that is laminated between the low acoustic velocity film and the material layer and propagates through the piezoelectric body is laminated.
- a high speed film is further provided, which is faster than the sound speed of. In this case, higher order modes can be effectively suppressed.
- the material layer is a support substrate.
- the material layer is made of a high sound velocity material in which the acoustic velocity of the propagating bulk wave is higher than the acoustic velocity of the elastic wave propagating through the piezoelectric body. It is a support substrate.
- the acoustic wave device further includes a support substrate laminated on a main surface opposite to the main surface on which the piezoelectric body is laminated in the material layer. ing.
- the high-frequency front-end circuit according to the present invention includes an elastic wave device configured according to the present invention and a power amplifier.
- a communication device includes a high-frequency front-end circuit having an elastic wave device and a power amplifier configured according to the present invention, and an RF signal processing circuit.
- the response of the higher-order mode positioned on the high-frequency side of the main mode is effectively suppressed while maintaining the characteristics of the main mode. It becomes possible.
- FIG. 1 is a front sectional view of an acoustic wave device according to a first embodiment of the present invention.
- FIG. 2 is a schematic plan view showing an electrode structure of the acoustic wave device according to the first embodiment of the present invention.
- FIG. 3 is a diagram showing phase characteristics of an acoustic wave device in which a silicon oxide film, a lithium tantalate film, and an IDT electrode made of Al are stacked on a material layer made of silicon using the silicon (100) surface. is there.
- FIG. 4 shows an elastic wave when the absolute value of the elastic constant C 56 is changed on the negative side with respect to a silicon single crystal having Euler angles ( ⁇ 45 °, ⁇ 54.7 °, 0 °).
- FIG. 5 is a schematic diagram showing the relationship between the coordinate system (X, Y, Z) and the Euler angles ( ⁇ , ⁇ , ⁇ ).
- FIG. 6 is a diagram showing the relationship between the elastic constant C 56 and the phase maximum value of the higher-order mode.
- FIG. 7 is a diagram showing the relationship between the elastic constant C 56 and the maximum phase value in the main mode.
- FIG. 8 is a diagram showing the relationship between the film thickness of the piezoelectric body and the higher-order mode phase difference.
- FIG. 9 is a diagram illustrating the relationship between the coordinate axes of the material layer and the piezoelectric body when the Euler angles are (0 °, 0 °, 0 °).
- FIG. 10 is a front cross-sectional view of an acoustic wave device according to a modification of the first embodiment.
- FIG. 11 is a front sectional view of an acoustic wave device according to the second embodiment of the present invention.
- FIG. 12 is a front sectional view of an acoustic wave device according to a third embodiment of the present invention.
- FIG. 13 is a schematic configuration diagram of a communication apparatus having a high-frequency front end circuit.
- FIG. 1 is a front sectional view of an acoustic wave device according to a first embodiment of the present invention
- FIG. 2 is a schematic plan view showing an electrode structure of the acoustic wave device according to the first embodiment.
- the acoustic wave device 1 has a material layer 2 made of silicon (Si) single crystal.
- a piezoelectric body 3 made of a lithium tantalate (LiTaO 3 ) single crystal is laminated. Therefore, the material layer 2 also has a function of a support substrate that supports the piezoelectric body 3 in this embodiment.
- the piezoelectric body 3 has first and second main surfaces 3a and 3b facing each other.
- the piezoelectric body 3 is directly laminated on the material layer 2 from the second main surface 3b side.
- An IDT electrode 4 and reflectors 5 and 6 are provided on the first main surface 3a.
- the surface acoustic wave device 1 is a surface acoustic wave device that uses surface acoustic waves propagating through a piezoelectric body 3.
- the elastic wave device is not limited to one using a surface acoustic wave.
- the IDT electrode 4 and the reflectors 5 and 6 are made of Al. But the IDT electrode 4 and the reflectors 5 and 6 may be comprised with another metal. Further, the IDT electrode 4 and the reflectors 5 and 6 may be made of a laminated metal film in which a plurality of metal films are laminated.
- the Euler angles (phi 1, theta 1, [psi 1) has a Euler angles (phi 1, theta 1, [psi 1) the elastic constant of represented by the following formula (1)
- the first and second main surfaces opposing the material layer are laminated directly or indirectly on the material layer from the second main surface side, and the Euler angles ( ⁇ 2 , ⁇ 2 , ⁇ 2 )
- a silicon oxide film, a lithium tantalate film, and an IDT electrode made of Al are laminated on a silicon single crystal.
- the thickness of the silicon oxide film was 0.35 ⁇
- the thickness of the lithium tantalate film was 0.3 ⁇
- the cut angle was 50 °
- the Euler angles were (0 °, 140 °, 0 °).
- the film thickness of the IDT electrode was 0.08 ⁇ .
- the main mode response appears in the vicinity of 3900 MHz in the elastic wave device using the silicon (100) surface that has been often used conventionally. Since it has the laminated structure as described above, the main mode characteristics are good. However, a higher-order mode response appears on the higher frequency side than the main mode, that is, in the vicinity of 5100 MHz. In this higher-order mode response, the phase maximum value is 90 °, and the higher-order mode response is very strong. Therefore, when an elastic wave filter or the like is configured using this elastic wave device, the filter characteristics of other bandpass filters may be deteriorated.
- multiplexers for carrier aggregation (CA) have been widely used in mobile communication devices such as smartphones.
- CA carrier aggregation
- a plurality of band-pass filters are commonly connected to the antenna terminal.
- one band-pass filter has the elastic wave device, if the pass band of another band-pass filter is at a frequency position including 5100 MHz, the filter characteristics of the other band-pass filter deteriorate. There is a fear. Therefore, suppression of the higher-order mode response is strongly required.
- the present inventor has examined the suppression of the higher order mode, the Euler angles ( ⁇ 1, ⁇ 1, ⁇ 1) having a Euler angle ( ⁇ 1, ⁇ 1, ⁇ 1) elastic constants in the following
- the material layer represented by the formula (1) has first and second main surfaces facing each other, and is laminated directly or indirectly on the material layer from the second main surface side.
- the elastic constants C 11 to C 66 are determinants represented by the following formula (1).
- FIG. 5 is a schematic diagram showing the relationship between the coordinate system (X, Y, Z) and the Euler angles ( ⁇ , ⁇ , ⁇ ).
- Euler angles ( ⁇ , ⁇ , ⁇ ) are based on the document “Acoustic Wave Element Technology Handbook” (Japan Society for the Promotion of Science Elastic Wave Element Technology 150th Committee, 1st edition, 1st edition, November 2001). The right-handed Euler angles described on the 30th, page 549) were used.
- the case of silicon will be described as an example. As shown in FIG. 5, the crystal axes of silicon are defined as an X axis, a Y axis, and a Z axis.
- Euler angles ( ⁇ , ⁇ , ⁇ ) are positive rotation directions of the right screw, and 1) rotate (X, Y, Z) by “ ⁇ ” around the Z axis, and (X 1 , Y 1 , Z 1 Then, 2) (X 1 , Y 1 , Z 1 ) is rotated by “ ⁇ ” around the X 1 axis to be (X 2 , Y 2 , Z 2 ). Face material layer to the Z 2 axis and the normal line, or a major surface of the piezoelectric body. 3) (X 2 , Y 2 , Z 2 ) is rotated by “ ⁇ ” about the Z 2 axis to obtain (X 3 , Y 3 , Z 3 ). At this time, the above-described rotation operation is expressed as ( ⁇ , ⁇ , ⁇ ) in Euler angles.
- the elastic constant represented by the equation (1) refers to an elastic constant obtained by performing coordinate conversion of the elastic constant by the above-described rotation operation with respect to the literature value of the elastic constant of the material layer or the piezoelectric body.
- ⁇ and ⁇ are as follows.
- l 1 to l 3 , m 1 to m 3, and n 1 to n 3 in ⁇ and ⁇ are as follows.
- the elastic constant c ab is an elastic constant after the elastic constant is coordinate-transformed by the rotation operation described above with respect to the literature value c ab 0 of the elastic constant of the material layer or the piezoelectric body. That is, even with the same material, each component of the elastic constant can take various values and signs depending on the Euler angle used.
- FIG. 9 shows the relationship between the coordinate axes of the material layer and the piezoelectric material when the Euler angles are (0 °, 0 °, 0 °).
- the X, Y, and Z axes in the left diagram of FIG. 9 are the crystal axes of the material layer, and Xa, Ya, and Za in FIG. 9 are the crystal axes of the piezoelectric body.
- X and Xa, Y and Ya, and Z and Za are defined in the same direction.
- the elastic wave propagating through the piezoelectric body is X propagation, the Xa direction and the IDT electrode are perpendicular to each other.
- the stress T a is the elastic constant C ab, which is the product of the strain S b.
- the elastic constant C ab is an elastic constant obtained by performing rotation processing corresponding to three Euler angles on a generally known silicon elastic constant tensor.
- the elastic constant in each crystal orientation can be derived by this coordinate conversion method. However, when the crystal orientation of the single crystal is rotated by a rotation operation, the elastic constant represented by the formula (1) changes.
- a piezoelectric body 3 having a thickness of 0.3 ⁇ made of lithium tantalate having a cut angle of 66 ° Y was laminated on the material layer 2 made of silicon single crystal.
- An IDT electrode 4 made of Al and having a thickness of 0.08 ⁇ was provided on the piezoelectric body 3. The wavelength determined by the electrode finger pitch of the IDT electrode 4 was 1.0 ⁇ m.
- the elastic constant of the piezoelectric body 3 in this case is as shown in Table 1 below. Here, those whose absolute values of C 11 to C 66 are 1.0 ⁇ 10 9 [Pa] or less are expressed as 0 [Pa] because the values are small and the influence is small. In Table 1, the significant figures are two digits.
- the elastic constant C 56 is ⁇ 8.4 ⁇ 10 9 [Pa], which is a negative value.
- the elastic constants C 11 to C 66 of the material layer 2 can be changed by rotating the crystal orientation. That is, the values of the elastic constants C 11 to C 66 can be changed by changing the propagation direction ⁇ , ⁇ , and ⁇ of silicon. Further, even if a material other than silicon is selected, the values of C 11 to C 66 can be changed. In other materials, the value varies depending on the orientation.
- C 11 to C 66 are as shown in Table 2 below.
- C56 is a negative value in any crystal orientation. Therefore, when the crystal orientation shown in Tables 2 and 3, the elastic constant C 56 of silicon, the C 56 of the piezoelectric element 3 shown in Table 1, the same sign for positive and negative.
- the absolute value of the C 56 in Table 2 is smaller than that of the piezoelectric body, in the case of Table 3 is greater than the value of the piezoelectric body.
- FIG. 4 shows the phase characteristics of the higher-order mode when changed in this way.
- the present inventor has an elastic constant C 56 of the silicon single crystal is varied over a wider range was investigated changes in phase the maximum value of the higher order modes of the acoustic wave device.
- FIG. 6 is a diagram showing the relationship between the elastic constant C 56 and the phase maximum value of the higher-order mode.
- the absolute value of C 56 is large, it can be seen that the phase maximum value of the higher order mode becomes smaller.
- the absolute value of the phase maximum value C 56 in the higher-order modes is less than 8.4GPa, not observed inhibitory effect of the higher order mode response. Therefore, the absolute value of the elastic constant C 56 is preferably not less than 8.4GPa.
- the limit that the absolute value is 8.4 GPa or more is a lower limit value when the piezoelectric body 3 made of lithium tantalate having the above crystal orientation and a silicon single crystal are used. In the case of using a piezoelectric body having another crystal orientation, this lower limit value is different.
- FIG. 7 is a graph showing changes in phase the maximum value of the main mode in the case of changing the elastic constant C 56 of the silicon single crystal.
- the material layer 2 becomes harder than the piezoelectric body 3 and when the piezoelectric body 3 is excited, the material layer 2 is hardly deformed by the higher order mode.
- the electrode structure and other design parameters so as to obtain good main mode characteristics, and adjusting the elastic constants, the response of higher order modes can be effectively suppressed.
- the horizontal axis of FIG. 8 is the piezoelectric film thickness, that is, the wavelength normalized film thickness of lithium tantalate, and the vertical axis is the higher-order mode phase difference (°).
- the high-order mode phase difference is the maximum value of the high-order mode phase difference when the Euler angle of the silicon single crystal is ( ⁇ 45 °, ⁇ 54.7 °, 0 °), and ( ⁇ 45 °, ⁇
- the difference from the maximum value of the higher-order mode phase difference in the case of 54.7 ° and 180 °) is shown.
- the larger the higher-order mode phase difference is, the more the response by the higher-order mode is suppressed. That is, the higher the higher-order mode phase difference, the greater the improvement in higher-order mode strength.
- the degree of improvement in higher-order mode strength is higher when the piezoelectric film is thinner. This is presumably because if the piezoelectric material is thin, more energy is distributed in the material layer made of silicon single crystal, and the effect of suppressing the response of higher-order modes is enhanced.
- the thickness of the piezoelectric body is preferably 10 ⁇ or less.
- the material layer 2 is made of a silicon single crystal, but the same effect can be obtained by using other single crystal materials. In addition, the same effect can be obtained if the material layer 2 is not limited to a single crystal but is made of a material whose elastic constant is represented by the formula (1).
- the material layer 2 is preferably made of a single crystal, more preferably a single crystal other than the piezoelectric body.
- a new higher-order mode may occur because the piezoelectric effect is exhibited.
- a material layer made of a single crystal other than the piezoelectric body it is difficult to be influenced by such higher order modes.
- lithium tantalate is used, but the piezoelectric single crystal constituting the piezoelectric body is not limited to these.
- the piezoelectric body and the material layer are directly laminated, but a low sound velocity film may be disposed therebetween.
- the energy concentration of the acoustic wave device can be increased, and device characteristics with low loss can be obtained.
- the low sound velocity film is made of silicon oxide. In this case, the temperature characteristics of the device can be improved.
- FIG. 10 is a front cross-sectional view of an elastic wave device according to a modification of the first embodiment.
- a support substrate 52 is laminated on the surface of the material layer 2 opposite to the surface in contact with the piezoelectric body 3.
- the support substrate 52 that supports the material layer 2 may be further provided.
- the material constituting the support substrate 52 is not particularly limited, and appropriate insulating ceramics such as alumina and silicon, metals, and the like can be used.
- FIG. 11 is a front sectional view of the acoustic wave device according to the second embodiment.
- a low acoustic velocity film 62 is laminated between the material layer 2 and the piezoelectric body 3.
- the low acoustic velocity film 62 is made of a low acoustic velocity material in which the acoustic velocity of the propagating bulk wave is lower than the acoustic velocity of the elastic wave propagating through the piezoelectric body 3.
- the low acoustic velocity film 62 is preferably made of silicon oxide.
- the other structure of the elastic wave device 61 is the same as that of the elastic wave device 1.
- FIG. 12 is a front sectional view of the acoustic wave device according to the third embodiment.
- a high acoustic velocity film 64 is provided between the low acoustic velocity film 62 and the material layer 2.
- the high acoustic velocity film 64 is made of a high acoustic velocity material in which the acoustic velocity of the propagating bulk wave is higher than the acoustic velocity of the elastic wave propagating through the piezoelectric body 3.
- the high acoustic velocity film 64 is preferably made of silicon nitride, aluminum oxide, DLC, or the like.
- the other structure of the elastic wave device 61 is the same as that of the elastic wave device 1.
- the film thickness of the piezoelectric body made of the lithium tantalate film is preferably 3.5 ⁇ or less. In that case, the Q value becomes higher than that in the case of exceeding 3.5 ⁇ . More preferably, in order to further increase the Q value, the film thickness of the lithium tantalate film is desirably 2.5 ⁇ or less.
- the absolute value of the frequency temperature coefficient TCF can be made smaller than when the thickness exceeds 2.5 ⁇ . More preferably, the film thickness is desirably 2 ⁇ or less, and in that case, the absolute value of the frequency temperature coefficient TCF can be 10 ppm / ° C. or less. In order to reduce the absolute value of the frequency temperature coefficient TCF, the film thickness of the piezoelectric body is more preferably set to 1.5 ⁇ or less.
- the thickness of the lithium tantalate film is preferably in the range of 0.05 ⁇ to 0.5 ⁇ .
- a film made of various high sound speed materials can be laminated as a high sound speed film on the surface of the silicon oxide film opposite to the piezoelectric body.
- a silicon nitride film, an aluminum oxide film, a DLC film, or the like can be used as the high sound velocity film.
- the electromechanical coupling coefficient and the sound speed hardly change even if the material of the high sound speed film and the film thickness of the silicon oxide film are changed.
- the film thickness of the silicon oxide film is 0.1 ⁇ or more and 0.5 ⁇ or less
- the electromechanical coupling coefficient hardly changes regardless of the material of the high acoustic velocity film.
- the film thickness of the silicon oxide film is 0.3 ⁇ or more and 2 ⁇ or less, the sound speed does not change regardless of the material of the high sound speed film. Therefore, preferably, the film thickness of the low acoustic velocity film made of silicon oxide is 2 ⁇ or less, more desirably 0.5 ⁇ or less.
- the elastic device of the above embodiment can be used as a component such as a duplexer of a high-frequency front end circuit.
- a high frequency front end circuit An example of such a high frequency front end circuit will be described below.
- FIG. 13 is a schematic configuration diagram of a communication apparatus having a high-frequency front end circuit.
- the communication device 240 includes an antenna 202, a high frequency front end circuit 230, and an RF signal processing circuit 203.
- the high frequency front end circuit 230 is a circuit portion connected to the antenna 202.
- the high frequency front end circuit 230 includes a multiplexer 210 and amplifiers 221 to 224.
- the multiplexer 210 has first to fourth filters 211 to 214.
- the elastic wave device of the present invention described above can be used for the first to fourth filters 211 to 214.
- the multiplexer 210 has an antenna common terminal 225 connected to the antenna 202.
- first to third filters 211 to 213 as a reception filter and one end of a fourth filter 214 as a transmission filter are commonly connected to the antenna common terminal 225.
- Output terminals of the first to third filters 211 to 213 are connected to the amplifiers 221 to 223, respectively.
- An amplifier 224 is connected to the input end of the fourth filter 214.
- the output terminals of the amplifiers 221 to 223 are connected to the RF signal processing circuit 203.
- An input terminal of the amplifier 224 is connected to the RF signal processing circuit 203.
- the device including the acoustic wave resonator may be a filter.
- the present invention may be, for example, a triplexer in which antenna terminals of three filters are shared, or a filter of six filters.
- the present invention can also be applied to a multiplexer such as a hexaplexer having a common antenna terminal.
- the multiplexer is not limited to the configuration including both the transmission filter and the reception filter, and may be configured to include only the transmission filter or only the reception filter.
- the acoustic wave device of the present invention can be widely used in communication devices such as mobile phones as filters, multiplexers applicable to multiband systems, front-end circuits, and communication devices.
Abstract
Description
l1=cosψcosφ-cosθsinφsinψ
l2=-sinψcosφ-cosθsinφcosψ
l3=sinθsinφ
m1=cosψsinφ+cosθcosφsinψ
m2=-sinψsinφ+cosθcosφcosψ
m3=-sinθcosφ
n1=sinψsinθ
n2=cosψsinθ
n3=cosθ
図1は、本発明の第1の実施形態に係る弾性波装置の正面断面図であり、図2は、第1の実施形態に係る弾性波装置の電極構造を示す模式的平面図である。
l1=cosψcosφ-cosθsinφsinψ
l2=-sinψcosφ-cosθsinφcosψ
l3=sinθsinφ
m1=cosψsinφ+cosθcosφsinψ
m2=-sinψsinφ+cosθcosφcosψ
m3=-sinθcosφ
n1=sinψsinθ
n2=cosψsinθ
n3=cosθ
タンタル酸リチウム膜からなる圧電体の膜厚は、3.5λ以下が好ましい。その場合には、3.5λを超えた場合に比べて、Q値が高くなる。より好ましくは、Q値をより高めるには、タンタル酸リチウム膜の膜厚は、2.5λ以下であることが望ましい。
2…材料層
3…圧電体
3a,3b…第1,第2の主面
4…IDT電極
5,6…反射器
51,61,63…弾性波装置
52…支持基板
62…低音速膜
64…高音速膜
202…アンテナ
203…RF信号処理回路
210…マルチプレクサ
211~214…第1~第4のフィルタ
221~224…増幅器
225…アンテナ共通端子
230…高周波フロントエンド回路
240…通信装置
Claims (24)
- オイラー角(φ1,θ1,ψ1)を有し、前記オイラー角(φ1,θ1,ψ1)における弾性定数が下記の式(1)で表される材料層と、
対向し合う第1及び第2の主面を有し、前記第2の主面側から前記材料層に直接または間接に積層されており、オイラー角(φ2,θ2,ψ2)を有し、前記オイラー角(φ2,θ2,ψ2)における弾性定数が下記の式(1)で表される圧電体と、
前記圧電体の前記第1の主面及び前記第2の主面のうちの少なくとも一方に設けられており、電極指ピッチで定まる波長がλであるIDT電極と、
を備え、
前記圧電体のC56と前記材料層のC56の積が正の値であり、かつ、
前記圧電体のC56の絶対値よりも前記材料層のC56の絶対値の方が大きい、弾性波装置。
- 前記IDT電極により励振される高次モードの少なくとも一部が、前記材料層と前記圧電体の両方を伝搬する、請求項1または2に記載の弾性波装置。
- 前記材料層が、前記圧電体を伝搬する弾性波の音速よりも、バルク波の音速が高速となる高音速材料である、請求項1~3のいずれか1項に記載の弾性波装置。
- 前記圧電体の厚みが10λ以下である、請求項1~3のいずれか1項に記載の弾性波装置。
- 前記材料層のC56の絶対値が8.4GPa以上である、請求項1~5のいずれか1項に記載の弾性波装置。
- 前記材料層のC56の絶対値が28GPa以下である、請求項1~5のいずれか1項に記載の弾性波装置。
- 前記材料層が単結晶からなる、請求項1~7のいずれか1項に記載の弾性波装置。
- 前記材料層を構成している前記単結晶が、圧電体以外の単結晶からなる、請求項8に記載の弾性波装置。
- 前記圧電体の厚みが、3.5λ以下である、請求項1~9のいずれか1項に記載の弾性波装置
- 前記圧電体の厚みが、2.5λ以下である、請求項10に記載の弾性波装置
- 前記圧電体の厚みが、1.5λ以下である、請求項11に記載の弾性波装置
- 前記圧電体の厚みが、0.5λ以下である、請求項12に記載の弾性波装置
- 前記材料層と、前記圧電体との間に設けられており、伝搬するバルク波の音速が、前記圧電体を伝搬する弾性波の音速よりも低速である低音速膜をさらに備える、請求項1~13のいずれか1項に記載の弾性波装置。
- 前記低音速膜が酸化ケイ素膜である、請求項14に記載の弾性波装置。
- 前記低音速膜の厚みが、2λ以下である、請求項15に記載の弾性波装置。
- 前記材料層を構成している前記単結晶が、シリコンからなる、請求項1~16のいずれか1項に記載の弾性波装置。
- 前記圧電体が、タンタル酸リチウムからなる、請求項1~16のいずれか1項に記載の弾性波装置。
- 前記低音速膜と、前記材料層との間に積層されており、伝搬するバルク波の音速が、前記圧電体を伝搬する弾性波の音速よりも高速である、高音速膜をさらに備える、請求項14~16のいずれか1項に記載の弾性波装置。
- 前記材料層が、支持基板である、請求項1~19のいずれか1項に記載の弾性波装置。
- 前記材料層が、伝搬するバルク波の音速が、前記圧電体を伝搬する弾性波の音速よりも高速である、高音速材料からなる支持基板である、請求項20に記載の弾性波装置。
- 前記材料層において前記圧電体が積層されている側の主面とは反対側の主面に積層されている支持基板をさらに備える、請求項1~20のいずれか1項に記載の弾性波装置。
- 請求項1~22のいずれか1項に記載の弾性波装置と、
パワーアンプと、
を備える、高周波フロントエンド回路。 - 請求項1~22のいずれか1項に記載の弾性波装置及びパワーアンプを有する高周波フロントエンド回路と、
RF信号処理回路と、
を備える、通信装置。
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WO2021215302A1 (ja) * | 2020-04-20 | 2021-10-28 | 株式会社村田製作所 | 複合基板及び弾性波装置 |
US11722117B2 (en) | 2019-12-06 | 2023-08-08 | Taio Yuden Co., Ltd. | Acoustic wave resonator, filter, multiplexer, and wafer |
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