The present disclosure describes a micromechanical resonator comprising a resonator element (40) having a length (l.sub.1) and a width (w.sub.1) that is perpendicular to the length. The resonator element has a length-to-width aspect ratio in a range of 1.8 to 2.2. The resonator element is suspended to a support structure with two or more anchors (41, 43). Each of the two or more anchors is attached to a first location or a second location. The first location is at a shorter side (42) of the resonator element. The first location divides the width (w.sub.1) of the resonator element into a larger portion (w.sub.3) and a smaller portion (w.sub.2) such that a ratio between said smaller portion (w.sub.2) and the whole width (w.sub.1) is in a range of 0.10 to 0.28. The second location is at a longer side (44). The second location divides the length (l.sub.1) of the resonator element into a larger portion (l.sub.3) and a smaller portion (l.sub.2) such that a ratio between said smaller portion (l.sub.2) and the whole length (l.sub.1) is in a range of 0.36 to 0.48.

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.

A resonator includes a vibration portion with upper and lower electrodes with a piezoelectric film disposed therebetween. Moreover, a protective film is provided to face the piezoelectric film with the upper electrode interposed therebetween and is exposed in a first region in the vibration portion. A conductive film is provided to face the piezoelectric film with the protective film interposed therebetween and is exposed in a second region that is adjacent to the first region in the vibration portion. A connection electrode is formed in the protective film to electrically connect the conductive film to the lower electrode. The upper electrode is formed such that an area of a region overlapping the conductive film is equal to or smaller than half of a total area of the conductive film and/or avoids the region overlapping the conductive film.

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.

Particle detection device comprising a support, a platform for receiving particles, four beams suspending the platform from the support, such that the platform can be made to vibrate, means for making said platform vibrate at a resonance frequency, means for detecting the displacement of the platform in a direction of displacement. Each beam has a length l, a width L and a thickness e and the platform has a dimension in the direction of displacement of the platform and in which in a device with out of plane mode l10L and the dimension of each beam in the direction of displacement of the platform is at least 10 times smaller than the dimension of the platform in the direction of displacement.

The present disclosure provides an aerosol sensing method. The aerosol sensing method includes steps of providing an entering process, providing a particle collecting process and providing a measuring process. The entering process is to allow an aerosol to enter a chamber of a thermal-piezoresistive oscillator-based aerosol sensor, and a thermal-piezoresistive resonator is disposed in the chamber. The particle collecting process is to allow particulate matters in the aerosol to land on at least one proof-mass of the thermal-piezoresistive resonator when the thermal-piezoresistive resonator is not driven. The measuring process is to use an electrical signal to drive the thermal-piezoresistive resonator and measure a resonant frequency of the thermal-piezoresistive resonator. The particle collecting process and the measuring process are operated in a repetitive cycle for measuring changes of the resonant frequency of the thermal-piezoresistive resonator to measure the particulate matters of the aerosol.

A resonator includes a vibration portion with upper and lower electrodes with a piezoelectric film disposed therebetween. Moreover, a protective film is provided to face the piezoelectric film with the upper electrode interposed therebetween and is exposed in a first region in the vibration portion. A conductive film is provided to face the piezoelectric film with the protective film interposed therebetween and is exposed in a second region that is adjacent to the first region in the vibration portion. A connection electrode is formed in the protective film to electrically connect the conductive film to the lower electrode. The upper electrode is formed such that an area of a region overlapping the conductive film is equal to or smaller than half of a total area of the conductive film and/or avoids the region overlapping the conductive film.

A piezoelectric device includes a piezoelectric body at least a portion of which can bend and vibrate, an upper electrode on an upper surface of the piezoelectric body and in which distortion of a crystal lattice is reduced as a distance from the upper surface of the piezoelectric body increases, a lower electrode on a lower surface of the piezoelectric body and in which distortion of a crystal lattice is reduced as a distance from the upper surface of the piezoelectric body increases, and a support substrate below the piezoelectric body, in which a recess extending from a lower surface of the support substrate toward the lower surface of the piezoelectric device is provided.

A piezoelectric device includes a piezoelectric single crystal body with a homogeneous polarization state and of which at least a portion flexurally vibrates, an upper electrode on an upper surface of the piezoelectric single crystal body, a lower electrode on a lower surface of the piezoelectric single crystal body, and a supporting substrate below the piezoelectric single crystal body. A recess extends from a lower surface of the supporting substrate toward the lower surface of the piezoelectric single crystal body.

A vibrator is provided that includes a substrate having a major surface defined in width and length directions and one or more electrodes formed at least in a substantial entire region of the major surface of the substrate in the length direction, and that performs, as main vibration, expansion-contraction vibration along the width direction in accordance with a voltage applied to the electrodes. Moreover, a holder surrounds at least a portion of the vibrator; and a holding arm connects the vibrator to the holder. Moreover, the vibrator has a width Wo in the width direction positioned at an end in the length direction and includes, to have a width Wm differing from the width Wo and positioned between a pair of ends opposing in the length direction, a variant portion at least one or more locations that is in a shape recessed or projecting in the width direction.