Back to results
US 12,574,005 B2Granted
Acoustic wave device
AssigneeMurata Manufacturing Co., Ltd.
InventorKatsuya Daimon
Life of this patent
Estimating the term…
Abstract
An acoustic wave device includes a piezoelectric substrate and an IDT electrode on the piezoelectric substrate and including electrode fingers. A portion where adjacent electrode fingers of the IDT electrode overlap each other in an acoustic wave propagation direction is an intersecting region. The intersecting region includes a central region located in a central portion in a direction in which the electrode fingers extend and first and second edge regions on both sides of the central region in the direction in which the electrode fingers extend. The acoustic wave device further includes dielectric films between the piezoelectric substrate and the electrode fingers in the first and second edge regions. The dielectric films include at least one of hafnium oxide, niobium oxide, tungsten oxide, or cerium oxide.
Claims18
An acoustic wave device comprising:
- a piezoelectric substrate;
- and
- an interdigital transducer (IDT) electrode on or above the piezoelectric substrate and including a plurality of electrode fingers;
- wherein
- a portion where adjacent electrode fingers of the plurality of electrode fingers of the IDT electrode overlap each other in an acoustic wave propagation direction is an intersecting region, and the intersecting region includes a central region located in a central portion in a direction in which the plurality of electrode fingers extend and a pair of edge regions on both sides of the central region in the direction in which the plurality of electrode fingers extend;
- the acoustic wave device further includes a dielectric film between the piezoelectric substrate and the plurality of electrode fingers in the pair of edge regions;
- and
- the dielectric film includes at least one of hafnium oxide, niobium oxide, tungsten oxide, or cerium oxide.
5 more elements
An acoustic wave device comprising:
- a piezoelectric substrate including a piezoelectric layer;
- and
- an interdigital transducer (IDT) electrode on or above the piezoelectric substrate and including a plurality of electrode fingers;
- wherein
- a portion where adjacent electrode fingers of the plurality of electrode fingers of the IDT electrode overlap each other in an acoustic wave propagation direction is an intersecting region, and the intersecting region includes a central region located at a central portion in a direction in which the plurality of electrode fingers extend and a pair of edge regions on both sides of the central region in the direction in which the plurality of electrode fingers extend;
- the acoustic wave device further includes a dielectric film between the piezoelectric substrate and the plurality of electrode fingers in the pair of edge regions;
- the piezoelectric layer is a lithium tantalate layer,
- the IDT electrode includes a main electrode layer, and the main electrode layer is an Al layer;
- and
- where λ [μm] is a wavelength defined by an electrode finger pitch of the IDT electrode, t_D [λ] is a thickness of the dielectric film, ε is a dielectric constant of the dielectric film, d [kg/m3] is a density of the dielectric film, Y [GPa] is a Young's modulus of the dielectric film, t_LT [λ] is a thickness of the piezoelectric layer, t_Al [λ] is a thickness of the main electrode layer of the IDT electrode, Vc is an acoustic velocity in the central region, and Ve is an acoustic velocity in the pair of edge regions, t_D [λ], ε, d [kg/m3], Y [GPa], t_LT [λ], and t_Al [λ] are values that make Ve/Vc derived by a following formula 1 less than 1:
- Ve/Vc=1.00431413354797+(−0.00285716659280799)×((d[kg/m3])−4.66559485530547)+0.0000854138472667538×((Y[GPa])−163.239549839228)+(−0.000350625383356713)×(ε−20.050911039657)+0.262088599487209×((t_D[λ])−0,00998794212218652)+(−000121829646867971)×((t_LT[λ])−0.29981243301179)+(−0.0171813623903716)×((t_Al[λ])−0.064995980707398)+0.0000011344571772174×(((d[kg/m3])−4.66559485530547)×((Y[GPa])−163.239549839228))+(−0.0000000938653776651)×(((Y[GPa])−163.239549839228)×((Y[GPa])−163.239549839228)−7625.27702101924)+0.0000162006962167552×((ε−20.050911039657)×(ε−20.050911039657)−125.050998634098)+(−0.286079428865232)×(((d[kg/m3])−4.66559485530547)×((t_D[λ])−0.00998794212218652))+0.00817326864820186×(((Y[GPa])−163.239549839228)×((t_D[λ])−0.00998794212218652))+(−0.0221047213078)×((ε−20.050911039657)×((t_D[λ])−0.00998794212218652))+(−17.2441046243263)×(((t_D[λ])−0.00998794212218652)×((t_D[λ])−0.00998794212218652)−0.0000249563122710345)+0.00438054956998946×(((d[kg/m3])−4.66559485530547)×((t_LT[λ])−0.29981243301179))+(−0.000147617022443897)×(((Y[GPa])−163.239549839228)×((t_LT[λ])−0,29981243301179))+(−0.23034817620302)×(((t_D[λ])−0.00998794212218652)×((t_LT[λ])−0.29981243301179))+(−0.0367578157483136)×(((t_LT[λ])−0.29981243301179)×((t_LT[λ])−0.29981243301179)−0.0199865671766099)+0.000409293299970899×(((Y[GPa])−163.239549839228)×((t_Al[λ])−0.064995980707398))+(−1.89603355496479)×(((t_D[λ])−0.00998794212218652)×((t_Al[λ])−0.064995980707398))+(−0.0528637488540428)×(((t_LT[λ])−0.29981243301179)×((t_Al[λ])−0.064995980707398)) formula 1.
8 more elements
Dependencies are inferred from the claim text.