Abstract: Disclosed are micromechanical resonators having features that compensate for process variations and provide improved inherent temperature stability. Exemplary resonators may comprise comb drive resonators or parallel-plate drive resonators. The resonators comprise a (silicon-on-insulator) substrate with resonator apparatus formed therein. The resonator apparatus has one or more anchors connected to the substrate, at least one excitation/sense port that is electrically insulated from the substrate, and a resonator. The resonator comprises one or more flexural members connected to the one or more anchors that are separated from the substrate and separated from the excitation/sense port by gaps. A mass is coupled to flexural members, is separated from the substrate, and comprises a grid. Process compensation is achieved using a resonator mass in the form of a grid of lines that form holes or lines through the mass, wherein widths of lines of the grid are approximately ? the width of the flexural members.

Abstract: Disclosed are micromechanical resonator apparatus having features that permit multiple resonators on the same substrate to operate at different operating frequencies. Exemplary micromechanical resonator apparatus includes a support substrate and suspended micromechanical resonator apparatus having a resonance frequency. In one embodiment, the suspended micromechanical resonator apparatus comprises a device substrate that is suspended from and attached to the support substrate, a piezoelectric layer formed on the suspended device substrate, and a plurality of interdigitated upper electrodes formed on the piezoelectric layer. In another embodiment, the suspended micromechanical resonator apparatus comprises a device substrate that is suspended from and attached to the support substrate, a lower electrode formed on the suspended device substrate, a piezoelectric layer formed on the lower electrode, and a plurality of interdigitated upper electrodes formed on the piezoelectric layer.

Abstract: Disclosed are micromechanical resonator apparatus having features that permit multiple resonators on the same substrate to operate at different operating frequencies. Exemplary micromechanical resonator apparatus includes a support substrate and suspended micromechanical resonator apparatus having a resonance frequency. In one embodiment, the suspended micromechanical resonator apparatus comprises a device substrate that is suspended from and attached to the support substrate, a piezoelectric layer formed on the suspended device substrate, and a plurality of interdigitated upper electrodes formed on the piezoelectric layer. In another embodiment, the suspended micromechanical resonator apparatus comprises a device substrate that is suspended from and attached to the support substrate, a lower electrode formed on the suspended device substrate, a piezoelectric layer formed on the lower electrode, and a plurality of interdigitated upper electrodes formed on the piezoelectric layer.

Abstract: Disclosed are micromechanical tapered I-shaped bulk acoustic resonators. An exemplary resonator is formed on a substrate, which is preferably silicon. The resonator has a central rod (or extensional member) coupled to two tapered lateral flanges (or flexural members). The central extensional member and tapered flexural members are separated from the substrate. One or more electrodes are disposed adjacent to the tapered flexural members, are separated therefrom by small gaps, and are separated from the substrate. One or more anchors are coupled to the substrate, are laterally separated from the central rod by small gaps, and are coupled to the central rod by supports. The one or more anchors support and suspend the central rod and flexural members from the substrate. Process compensation is achieved using the tapered flexural members.

Abstract: Disclosed are capacitive micromechanical resonators optimized for high Q, low motional impedance, and large tuning range. Exemplary resonators were fabricated using a HARPSS-on-SOI process, and demonstrated quality factors up to 119000 in vacuum. For resonators operating between 3 MHz and 30 MHz, the lowest extracted impedance is 218 k? and the largest electrostatic tuning coefficient is ?240 ppm/V2. The disclosed designs are applicable up to at least 200 MHz operation. An oscillator interface circuit comprising of a trans-impedance amplifier and an automatic bias generator providing a temperature-compensating bias voltage is also disclosed. Experiments show temperature drift reduction from 2800 ppm to 39 ppm over a 100° C. range. Process compensation (DFM) of micromechanical resonators, resonators having mass loading elements that allow generation of closely spaced frequencies, and coupled systems comprising of the resonators are also described.

Abstract: Disclosed are micromechanical resonator apparatus having features that permit multiple resonators on the same substrate to operate at different operating frequencies. Exemplary micromechanical resonator apparatus includes a support substrate and suspended micromechanical resonator apparatus having a resonance frequency. In one embodiment, the suspended micromechanical resonator apparatus comprises a device substrate that is suspended from and attached to the support substrate, a piezoelectric layer formed on the suspended device substrate, and a plurality of interdigitated upper electrodes formed on the piezoelectric layer. In another embodiment, the suspended micromechanical resonator apparatus comprises a device substrate that is suspended from and attached to the support substrate, a lower electrode formed on the suspended device substrate, a piezoelectric layer formed on the lower electrode, and a plurality of interdigitated upper electrodes formed on the piezoelectric layer.

Abstract: Disclosed are micromechanical resonators having features that compensate for process variations and provide improved inherent temperature stability. Exemplary resonators may comprise comb drive resonators or parallel-plate drive resonators. The resonators comprise a (silicon-on-insulator) substrate with resonator apparatus formed therein. The resonator apparatus has one or more anchors connected to the substrate, at least one excitation/sense port that is electrically insulated from the substrate, and a resonator. The resonator comprises one or more flexural members connected to the one or more anchors that are separated from the substrate and separated from the excitation/sense port by gaps. A mass is coupled to flexural members, is separated from the substrate, and comprises a grid. Process compensation is achieved using a resonator mass in the form of a grid of lines that form holes or lines through the mass, wherein widths of lines of the grid are approximately ? the width of the flexural members.

Abstract: Disclosed are micromechanical tapered I-shaped bulk acoustic resonators. An exemplary resonator is formed on a substrate, which is preferably silicon. The resonator has a central rod (or extensional member) coupled to two tapered lateral flanges (or flexural members). The central extensional member and tapered flexural members are separated from the substrate. One or more electrodes are disposed adjacent to the tapered flexural members, are separated therefrom by small gaps, and are separated from the substrate. One or more anchors are coupled to the substrate, are laterally separated from the central rod by small gaps, and are coupled to the central rod by supports. The one or more anchors support and suspend the central rod and flexural members from the substrate. Process compensation is achieved using the tapered flexural members.

Abstract: Disclosed are high frequency, vertical silicon bulk acoustic resonators. Resonator structures having a relatively large transduction areas fabricated using a HARPSS fabrication process provide for high frequency capacitive resonators with significantly low impedance values. Impedance values as low as a few kilo-Ohms to sub-kilo-Ohm and quality factors in the range of 20,000 to 90,000 in the VHF range have been achieved for a first thickness mode of fabricated vertical silicon bulk acoustic resonators. Resonant frequencies as high as 983 MHz have been demonstrated for higher third thickness modes of the vertical silicon bulk acoustic resonators.

Abstract: A piezoelectric resonator is disclosed. In one embodiment the piezoelectric resonator includes a resonating member having a bi-directionally adjustable resonance frequency, the resonating member including a semiconductor material of a semiconductor-on-insulator wafer, the semiconductor-on-insulator wafer including an oxide layer adjacent to the semiconductor material and a handle layer adjacent to the oxide layer, the oxide layer disposed between the handle layer and the semiconductor material, and electrode, and a piezoelectric material disposed between the semiconductor material and the electrode, and a capacitor created by the semiconductor material and the handle layer separated by an air gap formed out of the oxide layer, wherein the capacitor is configured to receive a direct current voltage that adjusts the resonance frequency of the resonating member.

Abstract: A piezoelectric resonator is disclosed. In one embodiment the piezoelectric resonator includes a semiconductor material, an electrode, and a piezoelectric material disposed between the semiconductor material and the electrode.