A resonance device that includes a lower cover formed from non-degenerate silicon; a resonator having a degenerate silicon substrate with a lower surface facing the lower cover, and including first and second electrode layers laminated on the substrate with a piezoelectric film formed therebetween and having a surface opposing an upper surface of the substrate. Moreover, the lower surface of the substrate has an adjustment region where a depth or height of projections and recesses formed on the surface is larger than that in another region of the lower surface of the substrate or is a region where an area of the projections and recesses is larger than that in the other region of the lower surface of the substrate.

Embodiments of the present disclosure relate generally to MEMS resonators. An exemplary MEMS resonator comprises a resonator beam having a length and a width. The length can be an integer multiple of the width. The integer multiple can be at least two. The resonator is configured to resonate at a frequency upon application of an input signal. The TCF of this resonator can be made close to zero, thus providing a temperature stable resonator. The exemplary MEMS resonator thereby has the advantages of high Q, low polarization voltage, low motional impedance and temperature stability of low frequency resonators while being able resonate at high frequencies of 30 MHz to 30 GHz.

A frequency adjustment method is provided in which a residual substance is unlikely to be generated, the frequency can be adjusted with high precision, and a decrease in strength is made small. A frequency adjustment method for a piezoelectric vibrator includes preparing the piezoelectric vibrator having a base portion, a vibration arm that includes a connection portion connected to the base portion as well as vibration arm main bodies extending from the connection portion and that is made of a single crystal, a lower electrode formed on the vibration arm, a piezoelectric thin film formed on the lower electrode, and an upper electrode formed on the piezoelectric thin film; and forming an alteration portion by irradiating the connection portion with a laser beam.

A piezoelectric vibrator that includes a piezoelectric film with a pair of electrodes disposed on opposing sides of the piezoelectric film. Moreover, the vibrator includes first and second adjustment films with the first adjustment film covering the first surface of the piezoelectric film in a first region and the second adjustment film covering the first surface of the piezoelectric film in a second region that is different from the first region. Moreover, the second region of the piezoelectric film has a greater displacement than the first region when the piezoelectric vibrator vibrates.

A micro-electrical-mechanical system (MEMS) guided wave device includes a plurality of electrodes arranged below a piezoelectric layer (e.g., either embedded in a slow wave propagation layer or supported by a suspended portion of the piezoelectric layer) and configured for transduction of a lateral acoustic wave in the piezoelectric layer. The piezoelectric layer permits one or more additions or modifications to be made thereto, such as trimming (thinning) of selective areas, addition of loading materials, sandwiching of piezoelectric layer regions between electrodes to yield capacitive elements or non-linear elastic convolvers, addition of sensing materials, and addition of functional layers providing mixed domain signal processing utility.

A micro-electrical-mechanical system (MEMS) guided wave device includes a plurality of electrodes arranged below a piezoelectric layer (e.g., either embedded in a slow wave propagation layer or supported by a suspended portion of the piezoelectric layer) and configured for transduction of a lateral acoustic wave in the piezoelectric layer. The piezoelectric layer permits one or more additions or modifications to be made thereto, such as trimming (thinning) of selective areas, addition of loading materials, sandwiching of piezoelectric layer regions between electrodes to yield capacitive elements or non-linear elastic convolvers, addition of sensing materials, and addition of functional layers providing mixed domain signal processing utility.

A micro-electrical-mechanical system (MEMS) guided wave device includes a plurality of electrodes arranged below a piezoelectric layer (e.g., either embedded in a slow wave propagation layer or supported by a suspended portion of the piezoelectric layer) and configured for transduction of a lateral acoustic wave in the piezoelectric layer. The piezoelectric layer permits one or more additions or modifications to be made thereto, such as trimming (thinning) of selective areas, addition of loading materials, sandwiching of piezoelectric layer regions between electrodes to yield capacitive elements or non-linear elastic convolvers, addition of sensing materials, and addition of functional layers providing mixed domain signal processing utility.

A calibration system is provided for an oven controlled MEMS oscillator. The calibration system includes control circuitry that to separately selects predetermined target set-point values and controls a heater inside the oven controlled MEMS oscillator based on each of the selected target set-point values to adjust a set-point of the oven controlled MEMS oscillator. The system further includes an oscillation measurement circuit that measures respective oscillation frequencies at each adjusted set-point corresponding to each of the selected predetermined target set-point values. The measured oscillation frequencies can then be used to determine a target set-point operation value for the oven controlled MEMS oscillator, which can be sued to calibrate the oven controlled MEMS oscillator.

A resonator is provided having a first electrode and a second electrode; and a piezoelectric film that is disposed between the first and second electrodes, has an upper surface opposing the first electrode, and that vibrates in a predetermined vibration mode when a voltage is applied between the first and second electrodes. Moreover, the resonator includes a protective film made of an insulator and disposed opposing the upper surface of the piezoelectric film with the first electrode interposed therebetween. Furthermore, a conductive film made of a conductor is provided that is disposed opposing the upper surface of the piezoelectric film with the protective film interposed therebetween, where the conductive film is electrically connected to any one of the first and second electrodes.

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.