Out-of plane MEMS resonator with static out-of-plane deflection
AssigneeSilicon Laboratories Inc.
InventorsEmmanuel P. Quevy, David A. Bernstein, Mehrnaz Motiee
Life of this patent
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Abstract
A residual stress gradient in a structural layer is employed to form a resonator deflected out of plane when at rest and the resulting strain gradient is utilized in out-of-plane transduction. Use of the strain gradient enables out-of-plane (e.g., vertical) transduction without yield and reliability problems due to stiction (e.g., the sticking of the resonator to the substrate) when the resonator is driven by an electrode to dynamically deflect out-of-plane. In particular embodiments, out-of-plane transduction is utilized to achieve better transduction efficiency as compared to lateral resonator designs of similar linear dimensions (i.e. footprint) results in a lower motional resistance.
Claims34
A MEMS device comprising:
- a resonator coupled to a substrate, the resonator including a strain gradient statically deflecting a first portion of the resonator;
- and
- a driver configured to drive the resonator in a resonant mode which varies the amount of deflection;
- wherein the resonator comprises:
- a cantilever beam;
- and
- a first plurality of lattice beams extending along a length of the cantilever beam.
A MEMS device comprising:
- a resonator coupled to a substrate, the resonator including a strain gradient statically deflecting a first portion of the resonator;
- and
- a driver configured to drive the resonator in a resonant mode which varies the amount of deflection,
- wherein the resonator is adjacent to two dimensions of a perimeter of an electrode of the driver,
- wherein the resonator comprises a plurality of lattice beams forming a lattice along a length of the resonator, wherein a subset of the lattice beams form a lattice opening perimeter surrounding the electrode.
A MEMS device, comprising:
- a substrate;
- and
- a resonator coupled to the substrate, wherein the resonator comprises a plurality of lattice beams forming a lattice along a length of the resonator, wherein a subset of the lattice beams form a perimeter surrounding an electrode,
- wherein the resonator has a strain gradient statically deflecting a first portion of the resonator away from the substrate.
A method of operating a MEMS resonator, the method comprising:
- causing a resonator to resonate in a torsional mode by providing a drive electrode with an AC signal, wherein a drive capacitance is substantially linear with dynamic displacement of the resonator and wherein the resonator includes a strain gradient statically deflecting the resonator in a direction substantially parallel with the direction of dynamic displacement;
- and
- detecting, with a sense electrode, a response based on the resonance of the resonator.
Dependencies are inferred from the claim text.