An acoustic wave device includes a piezoelectric substrate and an electrode on the piezoelectric substrate and including first and second layers. The first layer includes Al and Cu. The second layer is on a side opposite to a piezoelectric substrate side of the first layer and includes Al. The first layer includes an Al crystal and at least a portion of CuAl.sub.2 crystal grains that are provided in a direction orthogonal or substantially orthogonal to a thickness direction of the piezoelectric substrate. In the electrode, the CuAl.sub.2 crystal grains do not extend to the main surface of the second layer on a side opposite to a first layer side.

An acoustic resonator includes a piezoelectric thin film (PTF) disposed on a carrier substrate. The PTF confines a fundamental shear-horizontal (SH0) surface-acoustic wave (SAW) within the PTF. The acoustic resonator includes an input bus line coupled to an input source and a ground bus line coupled to a ground potential. The acoustic resonator includes a first grating reflector disposed at a first end of the PTF and coupled between the input bus line and the ground bus line. The acoustic resonator includes a second grating reflector disposed at a second end of the PTF and coupled between the input bus line and the ground bus line. The acoustic resonator includes interdigital transducers (IDTs) disposed between the first grating reflector and the second grating reflector. Each IDT includes an input electrode coupled to the input bus line, and a ground electrode coupled to the ground bus line.

A surface acoustic wave resonator includes first and second surface acoustic wave resonator connected in series, and a third surface acoustic wave resonator connected in series with the second surface acoustic wave resonator. Each of the first to third surface acoustic wave resonators includes a pair of comb-shaped electrodes in which electrode fingers of one of the comb-shaped electrodes and electrode fingers of the other one of the comb-shaped electrodes are alternately arranged. The second surface acoustic wave resonator has a lower ratio of a width of the electrode fingers to a pitch between the electrode fingers than the first and third surface acoustic wave resonators.

An electro-acoustic resonator comprises a piezoelectric substrate on which an electrode structure is disposed. The electrode structure comprises a metal layer of aluminum and copper, a barrier layer forming a barrier against the diffusion of copper and another metal layer disposed on the barrier layer comprising aluminum. An AlCu intermetallic phase formed after an anneal is restricted to the portion beneath the barrier layer so that Galvano-corrosion of the electrode structure is avoided.

An improved SAW (SAWR) resonator having an improved power durability and heat resistance and a protection to prevent device failure is provided. The SAW resonator has a carrier substrate (S) and an electrode structure (ES, EF) on a piezoelectric material (PM, PL). Further, the resonator has a shunt path (PCPP) parallel to the electrode structure and provided to enable an RF signal to bypass the electrode structure. The shunt path has a temperature dependent conductance with negative temperature coefficient of resistance.

A packaged acoustic wave component comprises a substrate having a trap-rich layer arranged at a surface of the substrate, a functional layer disposed over the surface of the substrate such as to cover that surface, a piezoelectric layer disposed over the functional layer and covering the functional layer with the exception of a peripheral portion of the functional layer, a first metal layer comprising an electrode structure disposed over the piezoelectric structure, and a second metal layer disposed partially in contact with the first metal layer and partially in contact with the peripheral portion of the functional layer.

There are disclosed acoustic resonators and radio frequency filter devices. An acoustic resonator includes a piezoelectric plate having a front surface. A conductor pattern is formed on the front surface, the conductor pattern including interdigital transducers (IDTs) of one or more pairs of sub-resonators, each pair consisting of two sub-resonators. The two sub-resonators of each pair of sub-resonators are positioned symmetrically about a central axis.

An acoustic wave device includes a high-acoustic-velocity support substrate, a low-acoustic-velocity film provided on the high-acoustic-velocity support substrate, a piezoelectric layer provided on the low-acoustic-velocity film, and an IDT electrode provided on the piezoelectric layer. An acoustic velocity of a bulk wave propagating through the high-acoustic-velocity support substrate is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer. An acoustic velocity of a bulk wave propagating through the low-acoustic-velocity film is lower than an acoustic velocity of a bulk wave propagating through the piezoelectric layer. The low-acoustic-velocity film has a first portion and a second portion that is located closer to the high-acoustic-velocity support substrate than the first portion. The first and second portions include the same or similar materials. A density in the first portion of the low-acoustic-velocity film and a density in the second portion of that are different.

A filter device according to an embodiment of the present disclosure includes a first filter and a second filter that are connected in parallel between a first terminal and a second terminal. The first filter includes multiple series arm resonators. The series arm resonators are disposed in series in a path from the first terminal via the first filter to the second terminal. The series arm resonators include a first series arm resonator and a second series arm resonator. Under a condition that a value obtained by dividing a difference between an antiresonance frequency and a resonance frequency of each series arm resonator by the resonance frequency is defined as a fractional bandwidth, a first fractional bandwidth of the first series arm resonator is different from a second fractional bandwidth of the second series arm resonator.

A filter device includes a first filter and a second filter. The first filter and the second filter are disposed in parallel between a first terminal and a second terminal. A first passband of the filter device includes at least part of a second passband of the first filter. The first passband includes at least part of a third passband of the second filter. The second passband is narrower than the first passband. The third passband is narrower than the first passband. The third passband has a center frequency higher than a center frequency of the second passband. The first filter includes multiple elastic wave resonators and a first capacitive element. The first capacitive element is connected in parallel with the first elastic wave resonator.