A method of manufacture and structure for a monolithic single chip single crystal device. The method can include forming a first single crystal epitaxial layer overlying the substrate and forming one or more second single crystal epitaxial layers overlying the first single crystal epitaxial layer. The first single crystal epitaxial layer and the one or more second single crystal epitaxial layers can be processed to form one or more active or passive device components. Through this process, the resulting device includes a monolithic epitaxial stack integrating multiple circuit functions.

The present disclosure provides a radio frequency filter, including: a substrate; a supporting electrode protruded on a front surface of the substrate; and a thin film structure formed on the substrate and spaced with the substrate by the supporting electrode. An end surface of a top end of the supporting electrode is in sealing contact with a front surface of the thin film structure.

An acoustic resonator package includes: a substrate; an acoustic resonator disposed on the substrate; a cap disposed on the substrate and the acoustic resonator; and a bonding portion bonding the substrate and the cap to each other. The cap includes a central portion accommodating the acoustic resonator, and an outer portion disposed outside of the central portion and having a bonding surface. The outer portion includes protrusions in contact with the bonding portion, and at least one trench disposed between the protrusions. The acoustic resonator package further includes a first protective layer and a second protective layer, the first protective layer and the second protective layer being disposed on a region of the bonding surface formed on each of the protrusions.

A high-frequency apparatus includes a resin substrate, a first device including a substrate and provided on the resin substrate, and a second device provided adjacent to the first device on the resin substrate. Each of the first device and the second device includes an acoustic wave device. The second device includes a piezoelectric substrate and a functional element provided on the piezoelectric substrate. The substrate of the first device includes Si or a laminated material including Si. The piezoelectric substrate of the second device includes LiTaO.sub.3, LiNbO.sub.3, or a laminated material including LiTaO.sub.3 or LiNbO.sub.3. The resin substrate includes glass.

An oven-controlled crystal oscillator according to one or more embodiments includes a core section having at least an oscillation IC, a crystal resonator, and a heater IC. The core section is hermetically encapsulated in a heat-insulating package. The core section is supported by the package via a core substrate. The core substrate is connected to the package outside a region where the core section is provided in plan view.

A bulk acoustic resonator package is provided. The bulk acoustic resonator package includes a substrate; a cap; a resonance portion including a first electrode, a piezoelectric layer, and a second electrode, stacked in a first direction in which the substrate and the cap face each other, and disposed between the substrate and the cap; and a cap melting member disposed to surround the resonance portion, and disposed to be in contact with a portion of a surface of the cap facing the substrate, when viewed in the first direction, and including a material or a structure that is based on a melting of the portion of the surface of the cap.

A crystal oscillator includes an oscillating substrate, a hollow frame, a first electrode, and a second electrode. The oscillating substrate includes a main oscillating region and a thinned region that has a thickness smaller than that of the main oscillating region. The first and second electrodes are disposed on a first surface of the oscillating substrate and a second surface opposite to the first surface, respectively. The hollow frame is disposed on the second surface. The second electrode includes a second electrode portion that has at least one opening in positional correspondence with the thinned region. A method for making the crystal oscillator is also provided herein.

A resonance device is provided that includes a lower lid that has a recessed portion, and a resonator that is mounted on the lower lid and has a vibration arm that performs out-of-plane bending vibration in a space including the recessed portion and a frame provided around the vibration arm and having a facing portion facing a tip of the vibration arm. The facing portion of the frame is located in an outer-side portion of the resonator with respect to a straight line connecting an intersection point of a perpendicular extending from the tip of the vibration arm toward the recessed portion of the lower lid and the recessed portion of the lower lid, to a cavity edge of the recessed portion facing the tip of the vibration arm.

An acoustic resonator package is provided. The acoustic resonator package includes a substrate, a cap, a plurality of acoustic resonators disposed between the substrate and the cap and configured to be electrically connected to each other, a grounding member disposed between the substrate and the cap, and a breakdown voltage shortener configured to provide an air gap to shorten a breakdown voltage between one of the plurality of acoustic resonators and the grounding member.

An acoustic wave device includes a first substrate, an acoustic wave element provided on a first surface of the piezoelectric layer, a second substrate, a first metal layer provided on the first surface and conductively connected to the acoustic wave element, a second metal layer provided on a second surface of the second substrate, a third metal layer that connects the first metal layer to the second metal layer, is thicker than the first metal layer and the second metal layer, and contains copper or silver, and a first conductive layer that covers a side surface of the third metal layer, and a third surface of the first metal layer in a region surrounding another region where the third metal layer is bonded to the first metal layer, is thinner than the third metal layer, and contains a component other than copper, silver, and tin as a main component.