A resonator including a lower electrode, an upper electrode, and a piezoelectric film that is formed between the lower electrode and the upper electrode. A MEMS device is provided that includes an upper lid that faces the upper electrode, and a lower lid that faces the lower electrode and that seals the resonator together with the upper lid. A CMOS device is mounted on a surface of the upper lid or the lower lid opposite a surface that faces the resonator. The CMOS device includes a CMOS layer and a protective layer that is disposed on a surface of the CMOS layer opposite a surface that faces the resonator. The upper or lower lid to which the CMOS device is joined includes a through-electrode that electrically connects the CMOS device to the resonator.

A suspended device structure comprises a substrate, a cavity disposed in a surface of the substrate, and a device suspended entirely over a bottom of the cavity. The device is a piezoelectric device and is suspended at least by a tether that physically connects the device to the substrate. The tether has a non-linear centerline. A wafer can comprise a plurality of suspended device structures. A device structure can comprise a device over a sacrificial portion or cavity and a tether with a tether opening extending to the sacrificial portion or cavity. The tether or tether opening can have a T shape. The tether can have a tether length at least one third as large as a device length and the device can have a device length at least twice as large as a device width.

A MEMS (microelectromechanical system) resonator with a material layer of single-crystalline silicon, at least one layer made of material with low thermal diffusivity to reduce thermoelastic dissipations in the MEMS resonator, a layer of piezoelectric material, and a layer made of electrically conducting material. The said-layer with low thermal diffusivity is between the single-crystalline silicon layer and the piezoelectric layer, or between the piezoelectric layer and the electrically conducting layer. The use of a material layer of low thermal diffusivity.

A piezoelectric film that includes crystalline AlN; at least one first element partially replacing Al in the crystalline AlN; and a second element doping the crystalline AlN and which has an ionic radius smaller than that of the first element and larger than that of Al.

An apparatus includes a substrate, a thin film piezoelectric layer, a transducer, and a low resistivity layer. The thin film piezoelectric layer is over the substrate, the transducer includes a number of electrodes in contact with the thin film piezoelectric layer and configured to transduce an acoustic wave in the thin film piezoelectric layer. The low resistivity layer is between at least a portion of the substrate and the thin film piezoelectric layer. By providing the low resistivity layer between at least a portion of the substrate and the thin film piezoelectric layer, a spurious response of the apparatus may be significantly reduced, thereby improving the performance thereof.

A resonator that includes a rectangular vibrating portion having first and second pairs of sides that provides contour vibration. A frame surrounds a periphery of the vibrating portion and a first holding unit between the frame and one of the first sides and includes a first arm substantially in parallel to the vibrating portion, multiple second arms connecting the first arm with the vibrating portion, and a third arm connecting the first arm with the frame. A first connection line is on the first arm; a first terminal is on the frame; three or more electrodes are on the vibrating portion; and multiple first extended lines are on the second arms and connect first and second electrodes with the first connection line. The first extended lines are connected to the first connection line, which is electrically connected to the first terminal.

A microelectromechanical resonator device has: a main body, with a first surface and a second surface, opposite to one another along a vertical axis, and made of a first layer and a second layer, arranged on the first layer; a cap, having a respective first surface and a respective second surface, opposite to one another along the vertical axis, and coupled to the main body by bonding elements; and a piezoelectric resonator structure formed by: a mobile element, constituted by a resonator portion of the first layer, suspended in cantilever fashion with respect to an internal cavity provided in the second layer and moreover, on the opposite side, with respect to a housing cavity provided in the cap; a region of piezoelectric material, arranged on the mobile element on the first surface of the main body; and a top electrode, arranged on the region of piezoelectric material, the mobile element constituting a bottom electrode of the piezoelectric resonator structure.

A method for adjusting a resonant frequency of a resonator without impairing piezoelectricity that includes preparing a lower lid; arranging a substrate with a lower surface that faces the lower lid and forming a first electrode layer, a piezoelectric film, and a second electrode layer on an upper surface of the substrate. Moreover, a vibration arm is formed that bends and vibrates from the first electrode layer, the second electrode layer, and the piezoelectric film and an upper lid faces the lower lid with the resonator interposed therebetween. The method further includes adjusting a frequency of the resonator before or after arranging the upper lid by exciting the vibration arm by applying a voltage between the first electrode layer and the second electrode layer and by causing a part of the vibration arm to collide with either or both of the lower lid and the upper lid.

Embodiments of the invention include a filtering device that includes a first electrode, a piezoelectric material in contact with the first electrode, and a second electrode in contact with the piezoelectric material. The piezoelectric filtering device expands and contracts laterally in a plane of an organic substrate in response to application of an electrical signal between the first and second electrodes.

A passive wireless sensor includes a substrate having at least one Microelectromechanical system (MEMS) piezoelectric resonator thereon. The MEMS piezoelectric resonator includes a piezoelectric layer between a top metal or semiconductor layer (top electrode layer) and a bottom metal or semiconductor layer (bottom electrode layer). The top electrode layer is a patterned top electrode layer including at least a first electrode for sensing an electrical signal and a second electrode for providing a ground reference. An antenna is connected to the first and/or second electrode for wirelessly transmitting the electrical signal and for receiving a wireless interrogation signal.