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WO2025192328A1 - Dispositif à ondes élastiques - Google Patents

Dispositif à ondes élastiques

Info

Publication number
WO2025192328A1
WO2025192328A1 PCT/JP2025/007351 JP2025007351W WO2025192328A1 WO 2025192328 A1 WO2025192328 A1 WO 2025192328A1 JP 2025007351 W JP2025007351 W JP 2025007351W WO 2025192328 A1 WO2025192328 A1 WO 2025192328A1
Authority
WO
WIPO (PCT)
Prior art keywords
wave device
piezoelectric body
elastic wave
thickness
idt electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2025/007351
Other languages
English (en)
Japanese (ja)
Inventor
惣一朗 野添
安藤　智洋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kyocera Corp
Original Assignee
Kyocera Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kyocera Corp filed Critical Kyocera Corp
Publication of WO2025192328A1 publication Critical patent/WO2025192328A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; 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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/25—Constructional features of resonators using surface acoustic waves

Definitions

  • This disclosure relates to an acoustic wave device.
  • FIG. 10 is a graph illustrating the phase characteristics of the elastic wave device according to the second embodiment, which are derived by simulation.
  • FIG. 10 is a cross-sectional view illustrating the configuration of a main part of an elastic wave device according to a third embodiment. 10 is a graph illustrating the phase characteristics of the elastic wave device according to the third embodiment, which are derived by simulation. 11 is a graph illustrating the relationship between the thickness of the first IDT electrode and the bandwidth in the acoustic wave device according to the third embodiment, derived by simulation.
  • FIG. 10 is a cross-sectional view illustrating the configuration of a main part of an elastic wave device according to a fourth embodiment. 10 is a graph illustrating the relationship between the taper angle and the maximum phase value in the elastic wave device according to Embodiment 4, derived by simulation.
  • (Configuration of Elastic Wave Device) 1 is a cross-sectional view illustrating the configuration of an elastic wave device 1 according to embodiment 1.
  • the elastic wave device 1 includes a piezoelectric body 10 and a first inter-digital transducer (IDT) electrode 20.
  • the elastic wave device 1 also includes a substrate 30.
  • the piezoelectric body 10 is an element that generates elastic waves.
  • the piezoelectric body 10 has a first surface 11.
  • the piezoelectric body 10 also has a second surface 12 located on the opposite side of the first surface 11.
  • the first surface 11 is the surface of the piezoelectric body 10 opposite the substrate 30.
  • the second surface 12 is the surface of the piezoelectric body 10 facing the substrate 30.
  • the piezoelectric body 10 has a plurality of first grooves 11a on the first surface 11.
  • the first IDT electrode 20 is an electrode that excites elastic waves in the piezoelectric body 10.
  • the first IDT electrode 20 extends in a direction perpendicular to the plane of the paper. For example, when an AC voltage is applied to such a first IDT electrode 20, elastic waves are excited in the piezoelectric body 10.
  • FIG. 2 is a plan view illustrating an example of the shape of the first IDT electrode 20.
  • the first IDT electrode 20 may have a first electrode finger group 21 and bus bars 22a and 22b.
  • the first electrode finger group 21 may include electrode fingers 21a and dummy electrode fingers 21b.
  • the electrode fingers 21a may be connected to either one of the bus bars 22a and 22b.
  • the electrode fingers 21a may be located in an intersection region where they intersect with electrode fingers 21a connected to bus bars 22a and 22b to which they are not connected.
  • the dummy electrode fingers 21b may be connected to either one of the bus bars 22a and 22b, be shorter than the electrode fingers 21a, and not be located in the intersection region.
  • the first electrode finger group 21 does not have to include dummy electrode fingers 21b.
  • first electrode finger group 21 is located inside first groove 11a. In FIG. 1, the entire first electrode finger group 21 is located inside first groove 11a. However, in acoustic wave device 1, a portion of first electrode finger group 21 may be located outside first groove 11a. Furthermore, at least a portion of bus bars 22a, 22b does not necessarily have to be located inside first groove 11a. In other words, the entirety of bus bars 22a, 22b may be located outside first groove 11a.
  • Substrate 30 is a substrate that supports piezoelectric body 10 and first IDT electrode 20.
  • Substrate 30 may have a recess 31 and a support portion 32 on the surface facing piezoelectric body 10.
  • Piezoelectric body 10 may be supported by being bonded to support portion 32. Therefore, acoustic wave device 1 may have a so-called membrane structure in which a cavity exists between piezoelectric body 10 and substrate 30.
  • the material of the substrate 30 may be, for example, silicon (Si), or other materials. Furthermore, the substrate 30 may be formed from a single material or multiple materials.
  • the substrate 30 having recesses 31 may be formed by etching the surface of a flat, plate-shaped substrate. In this case, the areas that are not etched become the support portions 32.
  • the substrate 30 having the support portions 32 may be formed by arranging the support portions 32 on a flat, plate-shaped substrate. In this case, the areas where the support portions 32 are not arranged become the recesses 31.
  • the piezoelectric body 10 includes AlN doped with Sc.
  • the entire piezoelectric body 10 may be made of AlN doped with Sc.
  • Such a piezoelectric body 10 may be formed, for example, by film deposition. In this case, the uniformity of the film thickness can be easily improved compared to when the piezoelectric body 10 is formed by polishing, for example. Furthermore, by forming the piezoelectric body 10 by film deposition, it is easier to create a structure in which at least a portion of the first IDT electrode 20 is located inside the first groove 11a, compared to when the piezoelectric body 10 is formed by polishing, for example.
  • Sc-doped AlN only has piezoelectricity e15 due to the electric field in the X direction, piezoelectricity e24 due to the electric field in the Y direction, and piezoelectricity e31, e32, and e33 due to the electric field in the Z direction. Therefore, when piezoelectric body 10 contains Sc-doped AlN, spurious emissions are less likely to occur in elastic wave device 1 compared to when piezoelectric body 10 contains LiNbO3 or LiTaO3 .
  • the pitch of the first electrode finger group 21 (described below) is 0.5 ⁇ m, and the piezoelectric body 10 requires a thickness accuracy of ⁇ 5 nm.
  • the material of the piezoelectric body 10 is lithium tantalate (LT) or lithium niobate (LN)
  • the piezoelectric body 10 must be formed by photolithography.
  • the voltage resistance of a piezoelectric body 10 made of LT or LN is lower than that of a piezoelectric body 10 made of AlN with added Sc, because the pitch of the first electrode finger group 21 is smaller.
  • the inventors of the present application performed a simulation of the phase characteristics of the elastic wave device 1 under the following conditions. Thickness of the piezoelectric body 10: 201 nm Material of the first electrode finger group 21: Al Thickness of the first electrode finger group 21: 40 nm Pitch of the first electrode finger group 21: 1 ⁇ m Duty of the first electrode finger group 21: 0.5 The pitch is the distance between adjacent electrode fingers in the first electrode finger group 21. The duty is the ratio of the width of the electrode fingers to the pitch.
  • the first electrode finger group 21 is assumed to extend infinitely on a plane with a constant pitch and duty.
  • the atomic ratio of Sc to Al was 40% Sc and 60% Al, which can be expressed as the chemical formula Sc 0.4 Al 0.6 N.
  • Literature values were used for the density, dielectric constant, elastic constant, piezoelectric constant, and elastic loss of Sc-doped AlN.
  • the Z-axis orientation was assumed, and the crystal orientation was fixed at (0°, 0°, 0°). That is, the Z-axis direction of the Sc-doped AlN was set to be along the thickness direction of the piezoelectric body 10.
  • FIG. 3 is a graph illustrating the phase characteristics of elastic wave device 1 derived by simulation.
  • the horizontal axis represents frequency and the vertical axis represents phase.
  • reference numeral 301 represents a graph covering a wide frequency range from 3 GHz to 12 GHz
  • reference numeral 302 represents a graph covering 8 GHz to 10 GHz, which is close to the band of elastic wave device 1.
  • the solid line represents the phase characteristics of elastic wave device 1
  • the dashed line represents the phase characteristics of an elastic wave device of a comparative example.
  • the resonant frequency of a given elastic wave device is the frequency at which the absolute value of the impedance of that elastic wave device is at its minimum.
  • the resonant frequency is also the frequency at which the phase is 0° in a frequency band where the phase monotonically increases.
  • the antiresonant frequency of a given elastic wave device is the frequency at which the absolute value of the impedance of that elastic wave device is at its maximum.
  • the antiresonant frequency is also the frequency at which the phase is 0° in a frequency band where the phase monotonically decreases.
  • the bandwidth of an elastic wave device is defined by the width of the band between the resonant frequency and antiresonant frequency of the elastic wave device.
  • the resonant frequency of elastic wave device 1 was higher than that of the comparative elastic wave device. Furthermore, the bandwidth of the comparative elastic wave device was 2.5% of the resonant frequency, while the bandwidth of elastic wave device 1 was 3.0% of the resonant frequency. In other words, elastic wave device 1 had a wider bandwidth than the comparative elastic wave device for waves with a sound speed of 18,000 m/s. Furthermore, as shown in FIG. 3, the magnitude of spurious signals near 7 GHz, 10 GHz, and 11 GHz was also reduced in elastic wave device 1 compared to the comparative elastic wave device.
  • the inventors of the present application performed a simulation on the thickness of the piezoelectric body 10 under the following conditions.
  • Material of the first electrode finger group 21 Al Thickness of the first electrode finger group 21: 40 nm Pitch of the first electrode finger group 21: 1 ⁇ m Duty of the first electrode finger group 21: 0.5 Under these conditions, the inventors of the present application performed simulations on the resonance frequency and bandwidth by varying the thickness of the piezoelectric body 10 .
  • FIG. 4 is a graph illustrating the relationship between the thickness of the piezoelectric body 10 in the elastic wave device 1 and the resonant frequency and bandwidth, as derived by simulation.
  • the horizontal axis represents the thickness of the piezoelectric body 10
  • the vertical axis on the left represents the resonant frequency
  • the vertical axis on the right represents the bandwidth.
  • reference numeral 401 represents the resonant frequency
  • reference numeral 402 represents the bandwidth.
  • both the resonant frequency and bandwidth monotonically decreased as the thickness of the piezoelectric body 10 increased.
  • the thickness of the piezoelectric body 10 may be 0.346 ⁇ m or less.
  • the resonant frequency of the elastic wave device 1 can be 6 GHz or higher.
  • first surface 11 is the surface of piezoelectric body 10 opposite substrate 30.
  • first surface 11 may also be the surface of piezoelectric body 10 facing substrate 30. That is, first IDT electrode 20 may be located on the opposite side of piezoelectric body 10 from substrate 30, or on the substrate 30 side of piezoelectric body 10. No significant difference was observed in the phase characteristics of elastic wave device 1 derived by simulation between when first IDT electrode 20 was located on the opposite side of piezoelectric body 10 from substrate 30 and when it was located on the substrate 30 side of piezoelectric body 10.
  • the acoustic wave device 1 has a membrane structure.
  • the acoustic wave device 1 may have a structure other than a membrane structure.
  • the acoustic wave device 1 may have a multilayer structure in which a dielectric multilayer film is present between the piezoelectric body 10 and the substrate 30.
  • the dielectric multilayer film may be a combination of a low acoustic impedance layer containing SiO 2 and a high acoustic impedance layer containing HfO 2 , for example.
  • the acoustic wave device will be described as having a membrane structure.
  • the acoustic wave device according to each embodiment is not limited to a membrane structure and may also have a multilayer film structure.
  • Fig. 5 is a cross-sectional view illustrating the configuration of a main part of an elastic wave device 2 according to embodiment 2. Substrate 30 included in elastic wave device 2 is omitted from Fig. 5. As shown in Fig. 5, elastic wave device 2 differs from elastic wave device 1 in that it includes piezoelectric body 10A instead of piezoelectric body 10 and in that it further includes a second IDT electrode 40.
  • first IDT electrode 20 is located on the first surface 11 side of piezoelectric body 10A
  • second IDT electrode 40 is located on the second surface 12 side of piezoelectric body 10A.
  • the bandwidth is wider and the magnitude of spurious signals is reduced compared to acoustic wave device 1, which does not have second IDT electrode 40.
  • the piezoelectric body 10A may have a plurality of second grooves 12a on the second surface 12. At least a portion of the second electrode finger group 41 may be located inside the second groove 12a. In FIG. 5, the entire second electrode finger group 41 is located inside the second groove 12a. However, the entire second electrode finger group 41 does not necessarily have to be located inside the second groove 12a, and some of the second electrode finger group 41 may be located outside the second groove 12a. This further widens the bandwidth and reduces the number of spurious signals compared to when the entire second electrode finger group 41 is arranged on the flat second surface 12.
  • the thickness of the first electrode finger group 21 may be smaller than the height of the first groove 11a. Furthermore, the thickness of the second electrode finger group 41 may be smaller than the height of the second groove 12a. This prevents the first electrode finger group 21 and the second electrode finger group 41 from protruding from the surface of the piezoelectric body 10A.
  • the inventors of the present application performed a simulation of the phase characteristics of the acoustic wave device 2 under the following conditions. Thickness of the piezoelectric body 10A: 201 nm Material of the first electrode finger group 21 and the second electrode finger group 41: Al Thickness of the first electrode finger group 21 and the second electrode finger group 41: 40 nm Pitch of the first electrode finger group 21 and the second electrode finger group 41: 1 ⁇ m Duty of the first electrode finger group 21 and the second electrode finger group 41: 0.5 In the simulation, the entire first electrode finger group 21 was positioned inside the first groove 11a, and the entire second electrode finger group 41 was positioned inside the second groove 12a.
  • Figure 6 is a graph illustrating the phase characteristics of elastic wave device 2 derived by simulation.
  • the horizontal axis represents frequency and the vertical axis represents phase.
  • reference numeral 601 represents a graph covering a wide frequency range from 3 GHz to 12 GHz
  • reference numeral 602 represents a graph covering 8 GHz to 10 GHz, which is close to the band of elastic wave device 2.
  • the solid line represents the phase characteristics of elastic wave device 2.
  • the dashed line represents the phase characteristics of elastic wave device 1, which were shown as solid lines in Figure 3.
  • the bandwidth of elastic wave device 1 was 3.0% of the resonant frequency.
  • the bandwidth of elastic wave device 2 was 3.5% of the resonant frequency, which was even wider than the bandwidth of elastic wave device 1.
  • the number of spurious signals was reduced in elastic wave device 2 compared to elastic wave device 1.
  • acoustic wave device 2 has a wider bandwidth and fewer spurious components than acoustic wave device 1 by including second IDT electrode 40 located on the second surface 12 side of piezoelectric body 10A.
  • second IDT electrode 40 located on the second surface 12 side of piezoelectric body 10A.
  • the bandwidth is further widened and the number of spurious components is reduced.
  • Fig. 7 is a cross-sectional view illustrating the configuration of a main portion of an elastic wave device 3 according to embodiment 3. Substrate 30 included in elastic wave device 3 is omitted from Fig. 7. As shown in Fig. 7, elastic wave device 3 differs from elastic wave device 1 in that piezoelectric body 10B is included instead of piezoelectric body 10. In piezoelectric body 10B, first surface 11 faces substrate 30 (see Fig. 1), opposite to piezoelectric body 10.
  • first IDT electrode 20 is located on the first surface 11 side of piezoelectric body 10.
  • second surface 12 of piezoelectric body 10 is flat.
  • piezoelectric body 10B may have a convex portion 12b in the region of second surface 12 that overlaps with first IDT electrode 20 when viewed in a direction perpendicular to second surface 12.
  • the inventors of the present application performed a simulation of the phase characteristics of the acoustic wave device 3 under the following conditions. Thickness of the piezoelectric body 10B: 201 nm Material of the first IDT electrode 20: Al Thickness of the first IDT electrode 20: 40 nm Pitch of the first IDT electrode 20: 1 ⁇ m Duty of the first IDT electrode 20: 0.5 Height of the protrusion 12b: 40 nm In the simulation, the entire first electrode finger group 21 was assumed to be located inside the first groove 11a.
  • Figure 8 is a graph illustrating the phase characteristics of elastic wave device 3 derived by simulation.
  • the horizontal axis represents frequency and the vertical axis represents phase.
  • reference numeral 801 represents a graph covering a wide frequency range from 3 GHz to 12 GHz
  • reference numeral 802 represents a graph covering 8 GHz to 10 GHz, which is close to the band of elastic wave device 3.
  • the solid line represents the phase characteristics of elastic wave device 3.
  • the dashed line represents the phase characteristics of elastic wave device 1, which were shown as solid lines in Figure 3.
  • the bandwidth in elastic wave device 1 was 3.0% of the resonant frequency.
  • the bandwidth in elastic wave device 3 was 2.8% of the resonant frequency, which was slightly lower than that of elastic wave device 1.
  • the bandwidth was 2.5% of the resonant frequency. Therefore, it can be said that elastic wave device 3 also had a wider bandwidth than an elastic wave device in which first electrode finger group 21 was not located inside first groove 11a.
  • the piezoelectric body 10B As an example of a method for manufacturing the piezoelectric body 10B, it is possible to first form the first IDT electrode 20 and then deposit the piezoelectric body 10B on top of it. In this manufacturing method, convex portions 12b resulting from the first IDT electrode 20 are formed on the surface of the deposited piezoelectric body 10B. In this manufacturing method, to obtain a piezoelectric body 10 without convex portions 12b as shown in FIG. 1, a process of removing the convex portions 12b after manufacturing the piezoelectric body 10B with the convex portions 12b is required.
  • the manufacturing cost of the piezoelectric body 10 without convex portions 12b is higher than the manufacturing cost of the piezoelectric body 10B.
  • acoustic wave device 3 can achieve a wider bandwidth than an acoustic wave device in which first electrode finger group 21 is not located inside first groove 11a, at a lower cost than acoustic wave device 1.
  • the bandwidth of acoustic wave device 3 is narrower than the bandwidth of acoustic wave device 1.
  • the height of the convex portion 12b may be between -20% and +20% of the depth of the first groove 11a.
  • the height of the convex portion 12b will be within the above range. Therefore, an additional process for adjusting the height of the convex portion 12b after forming the piezoelectric body 10B is not required, reducing the manufacturing cost of the piezoelectric body 10B.
  • the inventors of the present application performed a simulation under the following conditions to examine the relationship between the thickness of first IDT electrode 20 and the bandwidth of acoustic wave device 3 .
  • Thickness of the piezoelectric body 10B 201 nm Material of the first IDT electrode 20: Al Pitch of the first IDT electrode 20: 1 ⁇ m Duty of the first IDT electrode 20: 0.5
  • the inventors of the present application performed a simulation of the bandwidth by varying the thickness of the first IDT electrode 20.
  • the height of the protrusion 12b was set to be the same as the thickness of the first IDT electrode 20.
  • FIG. 9 is a graph illustrating the relationship between the thickness of the first IDT electrode 20 and the bandwidth in the acoustic wave device 3, as derived by simulation.
  • the horizontal axis represents the thickness of the first IDT electrode 20, and the vertical axis represents the bandwidth.
  • the lower horizontal axis represents the thickness of the first IDT electrode 20 in ⁇ m, and the upper horizontal axis represents the ratio (%) of the thickness of the first IDT electrode 20 to the thickness of the piezoelectric body 10B.
  • the bandwidth in the acoustic wave device 3 monotonically decreased as the thickness of the first IDT electrode 20 increased.
  • the bandwidth was 2.5% of the resonant frequency.
  • the bandwidth was 2.5% or more of the resonant frequency.
  • the thickness of first IDT electrode 20 may be 0.053 ⁇ m or less. Furthermore, according to simulations, when the thickness of first IDT electrode 20 is 26.4% or less of the thickness of piezoelectric body 10B, the bandwidth is 2.5% or more of the resonant frequency. Therefore, in acoustic wave device 3, the thickness of first IDT electrode 20 may be 26.4% or less of the thickness of piezoelectric body 10B. This makes the bandwidth of acoustic wave device 3 wider than the bandwidth of an acoustic wave device in which first electrode finger group 21 is not located inside first groove 11a.
  • ⁇ f is not significantly affected by the electrode thickness, unlike when the piezoelectric body 10B has the convex portion 12b. Therefore, when the piezoelectric body 10B does not have the convex portion 12b, it is easier to obtain the desired ⁇ f.
  • the cross-sectional shape of the first IDT electrode 20 is rectangular.
  • the cross-sectional shape of the first IDT electrode 50 may be tapered, with the side surfaces inclined at a predetermined taper angle ⁇ relative to the direction perpendicular to the first surface 11 when placed on the first surface 11.
  • Piezoelectric body 10C differs from piezoelectric body 10 in that it has first groove 11b instead of first groove 11a.
  • First groove 11b differs from first groove 11a in that it has a shape corresponding to first IDT electrode 50.
  • the shape of first groove 11b may be a tapered shape in which the side surface is inclined by a predetermined taper angle ⁇ with respect to the direction perpendicular to first surface 11.
  • the inventors of the present application performed a simulation under the following conditions to examine the relationship between the taper angle ⁇ of the elastic wave device 4 and the maximum phase value of the elastic wave device 4.
  • Thickness of the piezoelectric body 10C 201 nm Material of the first IDT electrode 50: Al Thickness of the first IDT electrode 50: 40 nm Pitch of the first IDT electrode 50: 1 ⁇ m
  • Duty of the first IDT electrode 50 0.5
  • the duty of the first IDT electrode 50 is determined using the width of the first IDT electrode 50 on the first surface 11 .
  • FIG. 11 is a graph illustrating the relationship between the taper angle ⁇ and the maximum phase value in the elastic wave device 4, derived through simulation.
  • the horizontal axis represents the taper angle ⁇
  • the vertical axis represents the maximum phase value.
  • the solid line represents the maximum phase value when a simulation is performed with the taper angle ⁇ actually set as the horizontal axis value.
  • the dashed line represents the maximum phase value when a simulation is performed with the taper angle ⁇ set to 0° in a simulation model for which the taper angle ⁇ is set as the horizontal axis value. Differences exist in the shape of the model depending on the taper angle ⁇ , and differences also arise in the maximum phase value when the taper angle ⁇ is set to 0° in that model. For this reason, the dashed line in the graph in Figure 11 is not constant relative to the horizontal axis.
  • the taper angle ⁇ when the taper angle ⁇ is greater than 0° and less than or equal to 68°, the maximum phase value in the elastic wave device 4 is greater than the maximum phase value in the elastic wave device 4 when the taper angle ⁇ is 0°.
  • the taper angle ⁇ when the taper angle ⁇ is greater than 68°, the maximum phase value in the elastic wave device 4 is less than the maximum phase value in the elastic wave device 4 when the taper angle ⁇ is 0°. Therefore, in the elastic wave device 4, the taper angle ⁇ may be greater than 0° and less than or equal to 68°. This allows the maximum phase value in the elastic wave device 4 to be greater than when the taper angle ⁇ is 0°.
  • the inclination of the side surfaces of the first groove 11b and the first IDT electrode 50 relative to the direction perpendicular to the first surface 11 was constant regardless of the depth from the bottom surface of the first groove 11b.
  • this inclination does not necessarily have to be constant.
  • the taper angle ⁇ may be the inclination of the side surfaces of the first groove 11b or the first IDT electrode 50 relative to the direction perpendicular to the first surface 11 at a height half the height from the bottom surface of the first groove 11b to the top surface of the first IDT electrode 50, for example.
  • Acoustic wave device 4 may further include a second IDT electrode located on the second surface 12 side of piezoelectric body 10C.
  • a second groove may be formed in second surface 12. At least a portion of the second electrode finger group included in the second IDT electrode may be located inside the second groove.
  • the second groove may have a tapered shape. If the second groove has a tapered shape, the taper angle of the second groove may be the same as or different from the taper angle ⁇ of first groove 11b.
  • the first surface 11 may be the surface of the piezoelectric body 10C facing the substrate 30.
  • the second surface 12 may have a convex portion in a region that overlaps with the first IDT electrode 50 when viewed from a direction perpendicular to the second surface 12.
  • the convex portion may have a tapered shape. If the convex portion has a tapered shape, the taper angle of the convex portion may be the same as or different from the taper angle ⁇ of the first groove 11b.
  • An acoustic wave device includes a piezoelectric body having a plurality of first grooves on a first surface, and a first IDT electrode having a first group of electrode fingers, at least a portion of which is located inside the first grooves, and the piezoelectric body includes AlN doped with Sc.
  • An elastic wave device is the same as aspect 2, except that the piezoelectric element has a second groove on the second surface, and the second IDT electrode has a second group of electrode fingers, at least a portion of which is located inside the second groove.
  • An elastic wave device is the same as aspect 3, except that the thickness of the first electrode finger group is smaller than the height of the first groove, and the thickness of the second electrode finger group is smaller than the height of the second groove.
  • An elastic wave device is any one of aspects 1 to 4, wherein the first groove has a tapered shape in which the side surface is inclined at a predetermined taper angle with respect to a direction perpendicular to the first surface, and the taper angle is greater than 0° and less than or equal to 68°.
  • the thickness of the piezoelectric body is 0.346 ⁇ m or less.
  • An elastic wave device is any one of aspects 1 to 6, wherein the piezoelectric element has a second surface located opposite the first surface, and the piezoelectric element has a convex portion on the second surface in a region that overlaps with the first IDT electrode when viewed in a direction perpendicular to the second surface.
  • An elastic wave device is the same as aspect 7, except that the thickness of the first IDT electrode is 0.09 ⁇ m or less.
  • An elastic wave device is the same as aspect 7 or 8, except that the thickness of the first IDT electrode is 44.3% or less of the thickness of the piezoelectric body.
  • An elastic wave device is any one of aspects 7 to 9, wherein the height of the convex portion is greater than or equal to -20% and less than or equal to +20% of the depth of the first groove.
  • An elastic wave device is any one of aspects 7 to 10, in which the thickness of the first IDT electrode is 0.053 ⁇ m or less.
  • An elastic wave device is any one of aspects 7 to 11, wherein the thickness of the first IDT electrode is 26.4% or less of the thickness of the piezoelectric body.
  • An elastic wave device is any one of aspects 1 to 12, in which the piezoelectric body has a membrane structure in which a cavity exists between the region in which the first IDT electrode is arranged and the substrate supporting the piezoelectric body, or a multilayer film structure in which a dielectric multilayer film exists between the piezoelectric body and the substrate.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

La présente invention élargit la largeur de bande d'un dispositif à ondes élastiques. Ce dispositif à ondes élastiques comprend : un corps piézoélectrique qui a une pluralité de premières rainures sur une première surface ; et une première électrode IDT qui a un premier groupe de doigts d'électrode et dans laquelle au moins une partie du premier groupe de doigts d'électrode est située à l'intérieur des premières rainures. Le corps piézoélectrique contient de l'AlN auquel Sc est ajouté.
PCT/JP2025/007351 2024-03-14 2025-03-03 Dispositif à ondes élastiques Pending WO2025192328A1 (fr)

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JP2018182354A (ja) * 2017-04-03 2018-11-15 株式会社村田製作所 弾性波装置
WO2021060507A1 (fr) * 2019-09-27 2021-04-01 株式会社村田製作所 Dispositif à ondes élastiques
JP2021141580A (ja) * 2020-02-28 2021-09-16 スカイワークス ソリューションズ, インコーポレイテッドSkyworks Solutions, Inc. バルク弾性波フィルタのための窒化アルミニウムドーパントスキーム
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WO2006046672A1 (fr) * 2004-10-26 2006-05-04 Koichi Hirama Circuit de resonance composite et circuit d’oscillation utilisant le circuit
WO2014054580A1 (fr) * 2012-10-05 2014-04-10 株式会社村田製作所 Dispositif à ondes élastiques de surface
JP2018506930A (ja) * 2014-12-17 2018-03-08 コルボ ユーエス インコーポレイテッド 波閉じ込め構造を有する板波デバイス及び作製方法
JP2018182354A (ja) * 2017-04-03 2018-11-15 株式会社村田製作所 弾性波装置
WO2021060507A1 (fr) * 2019-09-27 2021-04-01 株式会社村田製作所 Dispositif à ondes élastiques
JP2021141580A (ja) * 2020-02-28 2021-09-16 スカイワークス ソリューションズ, インコーポレイテッドSkyworks Solutions, Inc. バルク弾性波フィルタのための窒化アルミニウムドーパントスキーム
JP2022051000A (ja) * 2020-09-18 2022-03-31 ローム株式会社 圧電素子及びその製造方法、並びに、表面弾性波素子及び圧電薄膜共振素子

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