MEMS based sensors, particularly capacitive sensors, potentially can address critical considerations for users including accuracy, repeatability, long-term stability, ease of calibration, resistance to chemical and physical contaminants, size, packaging, and cost effectiveness. Accordingly, it would be beneficial to exploit MEMS processes that allow for manufacturability and integration of resonator elements into cavities within the MEMS sensor that are at low pressure allowing high quality factor resonators and absolute pressure sensors to be implemented. Embodiments of the invention provide capacitive sensors and MEMS elements that can be implemented directly above silicon CMOS electronics.

System and methods for a hollow-disk radial-contour mode resonator structure. The hollow disk reduces the dynamic mass and stiffness of the structure. Since electromechanical coupling C.sub.x/C.sub.o goes as the reciprocal of mass and stiffness, the hollow disk structure has a considerably stronger electromechanical coupling than a solid one at the same frequency, and thus raises C.sub.x/C.sub.o without excessive gap-scaling. Several embodiments of hollow disk resonators are detailed, including asymmetric and symmetric disk configurations.

Embodiments of the present disclosure relate generally to acoustically decoupled microelectromechanical system devices and, more particularly, to acoustically decoupled microelectromechanical system devices anchored upon phononic crystals. In some embodiments described herein, a device may comprise a resonator, a handle layer, and a pedestal disposed between the resonator and the handle layer, the pedestal connecting the resonator to the handle layer. In the devices described herein, the resonator and the handle layer may be non-coplanar. In some embodiments, the handle layer comprises a phononic crystal to acoustically decouple the resonator from the substrate of the handle layer.

According to one embodiment, a resonator is disclosed. The resonator includes a vibrator and an attenuation mechanism. The attenuation mechanism selectively attenuates vibration of a spurious mode that is mechanically coupled to a first mode when the vibrator vibrates in the first mode.

MEMS based sensors, particularly capacitive sensors, potentially can address critical considerations for users including accuracy, repeatability, long-term stability, ease of calibration, resistance to chemical and physical contaminants, size, packaging, and cost effectiveness. Accordingly, it would be beneficial to exploit MEMS processes that allow for manufacturability and integration of resonator elements into cavities within the MEMS sensor that are at low pressure allowing high quality factor resonators and absolute pressure sensors to be implemented. Embodiments of the invention provide capacitive sensors and MEMS elements that can be implemented directly above silicon CMOS electronics.

Reference oscillators are ubiquitous in timing applications generally, and in modern wireless communication devices particularly. Microelectromechanical system (MEMS) resonators are of particular interest due to their small size and potential for integration with other MEMS devices and electrical circuits on the same chip. In order to support their use in high volume low cost applications it would be beneficial for MEMS designers to have MEMS resonator designs and manufacturing processes that whilst employing low cost low resolution semiconductor processing yield improved resonator performance thereby reducing the requirements of the oscillator circuitry. It would be further beneficial for the oscillator circuitry to be able to leverage the improved noise performance of differential TIAs without sacrificing power consumption.

Micro-machined acoustic and ultrasonic transducer (MAUT), particularly piezoelectric MAUT (PMAUT), performance tradeoffs have meant reasonable pixel depth resolution necessitated low quality factor (Q) transducers with power distributed over a large bandwidth yielding modest imaging ranges whilst high-Q transducers providing higher acoustic power output for longer imaging ranges exhibit extended ringing limiting pixel depth information. Accordingly, the inventors have established MAUTs supporting high-Q transducers for long-range high-resolution imaging by integrating electromechanical actuators (dampers) which can be selectively engaged to mechanically damped the MAUT. In several applications PMAUT arrays are required where all transducer elements should have almost identical resonant frequencies. However, prior art fabrication processes have tended to produce PMAUTs with large inter-chip and inter-wafer variances. Prior art methodologies to reduce inter-wafer process variations do not address intra-wafer or inter-chip process variations and accordingly the inventors have established manufacturing methodologies and design solutions to address these for the PMAUT resonant frequency.

There are disclosed various apparatuses and methods for tuning a resonance frequency. In some embodiments there is provided an apparatus (200) comprising at least one input electrode (202, 204) for receiving radio frequency signals; a graphene foil (210) for converting at least part of the radio frequency signals into mechanical energy; at least one dielectric support element (212) to support the graphene foil (210) and to space apart the at least one input electrode (202, 204) and the graphene foil (210). The graphene foil (210) has piezoelectric properties. In some embodiments there is provided a method comprising receiving radio frequency signals by at least one input electrode (202, 204) of an apparatus (200); providing a bias voltage to the apparatus (200) for tuning the resonance frequency of the apparatus (200); and converting at least part of the radio frequency signals into mechanical energy by a graphene foil (210) having piezoelectric properties.

Micromachined microelectromechanical systems (MEMS) based resonators offer integration with other MEMS devices and electronics. Whilst piezoelectric film bulk acoustic resonators (FBAR) generally exhibit high electromechanical transduction efficiencies and low signal transmission losses they also suffer from low quality factors and limited resonance frequencies. In contrast electrostatic FBARs can yield high quality factors and resonance frequencies but suffer from increased fabrication complexity. lower electromechanical transduction efficiency and significant signal transmission loss. Accordingly, it would be beneficial to overcome these limitations by reducing fabrication complexity via a single metal electrode layer topping the resonator structure and supporting relatively low complexity/low resolution commercial MEMS fabrication processes by removing the fabrication requirement for narrow transduction gaps. Beneficially, embodiments of the invention provide MEMS circuits with electrostatic tuning and provide resonator designs combining the advantages of piezoelectric actuation and bulk-mode resonators.

A resonator element of the monocrystalline 4H or 6H polytype of silicon carbide. A MEMS device including the resonator element and a substrate, wherein the resonator element and the substrate are not coplanar, and acoustic decoupling of the resonator element and the substrate is at least partially dependent upon a degree to which the resonator element and the substrate are not coplanar. A MEMS gyroscope including the resonator element, a substrate, one or more electrodes disposed proximate the resonator element, and a capacitive gap disposed between each electrode and the resonator element. A MEMS device including the resonator element having has a Q greater than 1,000,000, a phononic crystal substrate, and a gap disposed between a perimeter edge of the resonator element and the phononic crystal substrate, wherein acoustic decoupling of the resonator element and the phononic crystal substrate is at least partially dependent upon a size of the gap.