A lead-out wiring, which is connected to a comb-shaped electrode formed on a principal surface of a piezoelectric substrate and is disposed to extend to an outer edge of the piezoelectric substrate an outer surrounding wall layer, which is arranged surrounding an outer periphery of the piezoelectric substrate including the lead-out wiring and forms a hollow portion that serves as an operation space for the comb-shaped electrode, and a top board, which bridges the outer surrounding wall layer to seal the hollow portion, are included.

A metallization, for carrying current in an electrical component, includes a bottom layer overlying a substrate surface and includes titanium (Ti) or a titanium compound as main constituent. An upper layer overlies the bottom layer and includes copper (Cu) as main constituent. The bottom layer and the upper layer form a base layer. A top layer is in direct contact with the upper layer and includes aluminum (Al) as main constituent. The base layer further includes a middle layer, consisting of silver, that is arranged between the bottom layer and the upper layer.

A SAW device includes a SAW element, a conductor connected to the SAW element, an LT substrate including the SAW element, and a case for housing the LT substrate including the SAW element. The case includes a cover part, a lateral part, and a bottom part. The bottom part is including a sapphire substrate, the LT substrate is positioned on a first surface of the sapphire substrate, the first surface serving as an inner surface of the case, and a second surface opposite to the first surface serves as an outer surface of the case. The conductor includes a via conductor provided in a through-hole continuously penetrating through the sapphire substrate and the LT substrate.

A surface acoustic wave resonator includes: a piezoelectric substrate; a plurality of metal structures formed on a top surface of the piezoelectric substrate to have a negative profile; and a temperature compensation layer covering the top surface of the piezoelectric substrate and the plurality of metal structures. The surface acoustic wave resonator according to an embodiment of the present invention has a frequency characteristic insensitive to change of profile and has an effect of having a high semi-resonance Q value characteristic.

A SAW resonator which, using a quartz crystal substrate with Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, and 41.9°≦|ψ|≦49.57°, includes an IDT that excites a stop band upper end mode SAW, and an inter-electrode finger groove provided between electrode fingers configuring the IDT. When a wavelength of the SAW is λ, a first depth of the inter-electrode finger groove is G, a line occupation rate of the IDT is η, and an electrode film thickness of the IDT is H, λ, G, η and H satisfy the relationship of 0<H≦0.005λ, 0.01λ≦G≦0.09λ, and 0.18≦η≦0.71.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a mass loading strip. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can have a sidewall that is tapered inwardly from a bottom side of the mass loading strip to a top side of the mass loading strip. The top side can be shorter than the bottom side.

A high-order mode surface acoustic wave device includes a piezoelectric substrate (11) formed from a LiTaO.sub.3 or LiNbO.sub.3 crystal and an interdigital transducer electrode (12) embedded in a surface of the piezoelectric substrate (11) to use a surface acoustic wave in a high-order mode. Further, the high-order mode surface acoustic wave device may include a film (13) or substrate stacked on the piezoelectric substrate (11), and may include a support substrate (11) and/or a multi-layer film (15) provided in contact with a surface opposite to the surface of the piezoelectric substrate (11) on which the interdigital transducer electrode (12) is provided. The high-order mode surface acoustic wave device may achieve good characteristics and maintain a sufficient mechanical strength even in a high frequency band of 3.8 GHz or greater.

Surface acoustic wave device having mass-loaded electrode. In some embodiments, a surface acoustic wave device for providing resonance of a surface acoustic wave having a wavelength λ can include a quartz substrate and a piezoelectric plate formed from LiTaO.sub.3 or LiNbO.sub.3 disposed over the quartz substrate. The piezoelectric plate can have a thickness greater than 2λ. The surface acoustic wave device can further include an interdigital transducer electrode formed over the piezoelectric plate. The interdigital transducer electrode can have a mass density ρ in a range 1.50 g/cm.sup.3<ρ≤6.00 g/cm.sup.3, 6.00 g/cm.sup.3<ρ≤12.0 g/cm.sup.3, or 12.0 g/cm.sup.3<ρ≤23.0 g/cm.sup.3, and a thickness greater than 0.148λ, greater than 0.079λ, or greater than 0.036λ, respectively.

An acoustic wave device that has a better TCF and can improve a resonator Q or impedance ratio is provided. The acoustic wave device includes a substrate 11 containing 70 mass % or greater of silicon dioxide (SiO.sub.2), a piezoelectric thin film 12 including LiTaO.sub.3 crystal or LiNbO.sub.3 crystal and disposed on the substrate 11, and an interdigital transducer electrode 13 disposed in contact with the piezoelectric thin film 12.

An apparatus is disclosed for suspending an electrode structure using a dielectric. In an example aspect, the apparatus includes a surface-acoustic-wave filter with a piezoelectric layer and an electrode structure. The electrode structure has a first surface facing the piezoelectric layer and separated from the piezoelectric layer by a distance. The surface-acoustic-wave filter also includes a dielectric disposed on at least one other surface of the electrode structure and configured to extend past a plane defined by the first surface of the electrode structure and toward the piezoelectric layer to define a cavity between at least a portion of the first surface of the electrode structure and the piezoelectric layer.