A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.

A compound spring MEMS resonator includes a resonator body constructed using one or more spring unit cells forming a compound spring block and one or more compound spring blocks forming the resonator body. Each compound spring block is anchored at nodal points to ensure a high quality factor. The resonator body further includes masses attached to the open ends of the compound spring block and capacitively coupled to drive/sense electrodes. The dimensions of the spring unit cells, the number of spring unit cells for a compound spring block, the size and weight of the masses, and the length and width of the support beams are selected to realize a desired resonant frequency. Meanwhile, the number of compound spring blocks is selected to tune the desired electrical characteristics, such as impedance, of the MEMS resonator.

A multiple coil spring MEMS resonator includes a center anchor and a resonator body including two or more coil springs extending in a spiral pattern from the center anchor to an outer closed ring. Each pair of coil springs originates from opposing points on the center anchor and extends in the spiral pattern to opposing points on the outer ring. The number of coil springs, the length and the width of the coil springs and the weight of the outer ring are selected to realize a desired resonant frequency.

The present invention relates to a filter chip (1), comprising an interconnection of at least one first and one second resonator (2, 3) operating with bulk acoustic waves, wherein the first resonator (2) operating with bulk acoustic waves comprises a first piezoelectric layer (4) that is structured in such a way that the first resonator (2) has a lower resonant frequency than the second resonator (3).

A MEMS (microelectromechanical system) resonator assembly (100), comprising a support structure (102), a resonator element (101) suspended to the support structure (102), and an actuator for exciting the resonator element (101) to a resonance mode. The resonator element (101) vibrates at resonance frequency f.sub.0 and comprises at least one bulk acoustic resonator (110a, 110b). The ESR*A*f.sub.0 values of the resonator assembly (100) are in the range from 12 mm.sup.2 MHz to 83 mm.sup.2 MHZ.

A MEMS (microelectromechanical system) resonator assembly (100), comprising a support structure (102), a resonator element (101) suspended to the support structure (102), and an actuator for exciting the resonator element (101) to a resonance mode. The resonator element (101) comprises two bulk acoustic resonators (110a, 110b) and a flexural mode resonator (120). The flexural mode resonator (120) mechanically connects the two bulk acoustic resonators (110a, 110b), and the MEMS resonator assembly (100) is configured to vibrate in a collective resonance mode in which motions of the two bulk acoustic resonators (110a, 110b) are substantially in the same or 180 degrees shifted phase with respect to each other.

A method of forming a resonator by providing a first layer; forming a sacrificial layer on the first layer; forming a capping layer on the sacrificial layer; forming at least one etching aperture in the capping layer; forming at least one additional aperture having a different size than the at least one etching aperture; forming a cavity and releasing a resonator structure within the cavity by removing the sacrificial layer by etching via the at least one etching aperture; sealing the at least one etching aperture; and forming a lining in the at least one additional aperture.

Embodiments of the invention include micromechanical resonators. These resonators can be fabricated from thin silicon layers. Both rotational and translational resonators are disclosed. Translational resonators can include two plates coupled by two resonate beams. A stable DC bias current can be applied across the two beams that causes the plates to resonate. In other embodiments, disk resonators can be used in a rotational mode. Other embodiments of the invention include using resonators as timing references, frequency sources, particle mass sensors, etc.

A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.

A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.