A resonator device includes: a resonator element; a first package that accommodates the resonator element; and a second package in which the first package is accommodated and fixed. The first package includes a base substrate that has a first surface on which the resonator element is disposed and a second surface which is in a front-back relationship with the first surface, and that contains single crystal silicon, an integrated circuit that is provided on the first surface or the second surface and that includes a temperature sensor circuit and a heater circuit, and a lid that is bonded to the base substrate such that the resonator element is accommodated between the lid and the base substrate.

Fabricating of radio-frequency (RF) devices involve providing a field-effect transistor (FET) formed over an oxide layer formed on a semiconductor substrate, removing at least part of the semiconductor substrate to expose at least a portion of a backside of the oxide layer, applying a sacrificial material to the backside of the oxide layer, applying an interface material to at least a portion of the backside of the oxide layer, the interface material at least partially covering the sacrificial material, and removing at least a portion of the sacrificial material to form a cavity at least partially covered by the interface layer.

A resonator device includes: a resonator element; a first package that accommodates the resonator element; and a second package in which the first package is accommodated and fixed. The first package includes a base substrate that has a first surface on which the resonator element is disposed and a second surface which is in a front-back relationship with the first surface, and that contains single crystal silicon, an integrated circuit that is provided on the first surface or the second surface and that includes a temperature sensor circuit and a heater circuit, and a lid that is bonded to the base substrate such that the resonator element is accommodated between the lid and the base substrate.

A device employing the generation and enhancement of surface acoustic waves on a highly doped p-type III-V semiconductor substrate (e.g., GaAs, GaSb, InAs, or InGaAs). The device includes two SiO.sub.2/ZnO islands, each including a SiO.sub.2 buffer layer deposited on the doped p-type III-V semiconductor substrate and a ZnO layer deposited on the SiO.sub.2 buffer layer. An input interdigital transducers (IDT) and an output IDT are each patterned on one of the SiO.sub.2/ZnO islands. The IDTs generates surface acoustic waves along an exposed surface of the highly doped p-type III-V semiconductor substrate. The surface acoustic waves improve the photoelectric and photovoltaic properties of the device. The device is manufactured using a disclosed technique for propagating strong surface acoustic waves on weak piezoelectric materials. Also disclosed is a photodetector developed using that technique.

Embodiments disclosed herein include diagnostic substrates and methods of using such substrates. In an embodiment, a diagnostic substrate comprises a substrate, and a device layer over the substrate. In an embodiment, the diagnostic substrate further comprises a resonator in the device layer. In an embodiment, the resonator comprises a cavity, a cover layer over the cavity, and electrodes within the cavity for driving and sensing resonance of the cover layer. In an embodiment, the diagnostic substrate further comprises a reflector surrounding a perimeter of the resonator.

An elastic wave device includes a SiN.sub.x layer stacked directly or indirectly on a supporting substrate made of a semiconductor material, a piezoelectric film stacked on directly or indirectly the SiN.sub.x layer, and an interdigital transducer electrode stacked directly or indirectly on at least one main surface of the piezoelectric film. In the SiN.sub.x layer, x is about 1.34 or more and about 1.66 or less.

An acoustic wave device includes a semiconductor substrate having a first main surface and a second main surface, a piezoelectric thin film provided directly on or indirectly above the first main surface of the semiconductor substrate, and an IDT electrode provided on the piezoelectric thin film. A semiconductor defining the semiconductor substrate is a high acoustic velocity material in which an acoustic velocity of a bulk wave propagating therethrough is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric thin film. The semiconductor substrate includes a first region including the first main surface and a second region which is a region other than the first region and includes the second main surface. An electric resistance of the first region is lower than an electric resistance of the second region.

An acoustic wave device includes a silicon substrate, a polysilicon layer provided on the silicon substrate, a silicon oxide layer directly or indirectly provided on the polysilicon layer, a piezoelectric layer directly or indirectly provided on the silicon oxide layer, and an interdigital transducer electrode provided on the piezoelectric layer. A plane orientation of the silicon substrate is any one of (100), (110), and (111), and, where a wave length that is defined by an electrode finger pitch of the interdigital transducer electrode is λ, a thickness of the piezoelectric layer is less than or equal to about 1λ.

A guided surface acoustic wave (SAW) device includes a substrate, a piezoelectric layer on the substrate, and a transducer on the piezoelectric layer. The substrate is silicon, and has a crystalline orientation defined by a first Euler angle (ϕ), a second Euler angle (θ), and a third Euler angle (ψ). The first Euler angle (ϕ), the second Euler angle (θ), and the third Euler angle (ψ) are chosen such that a velocity of wave propagation within the substrate is less than 6,000 m/s.

An acoustic wave resonator is disclosed. The acoustic wave resonator can include a plurality of interdigital transducer electrodes and a multilayer piezoelectric substrate (MPS) adjacent the plurality of interdigital transducer electrodes. The MPS includes a first substrate layer of a piezoelectric material, and a second substrate layer of silicon that is bonded to the first layer. The silicon has a cut direction and/or acoustic wave propagation direction that is different from those of a silicon substrate. The silicon substrate has a cut direction and a propagation direction property defined by the silicon cut angle of {100} and the propagation direction <110>.