OUT-OF-PLANE MEMS RESONATOR WITH STATIC OUT-OF-PLANE DEFLECTION

• US 20110260810A1
• Filed: 06/30/2011
• Published: 10/27/2011
• Est. Priority Date: 07/29/2008
• Status: Active Grant

• Current Assignee: Semiconductor Manufacturing International Corporation
• Original Assignee: David H. Bernstein, Emmanuel P. Quevy, Mehrnaz Motiee
• Inventors: Motiee, Mehrnaz, Quevy, Emmanuel P., Bernstein, David H.
• Granted Patent: US 8,258,893 B2
• Time in Patent Office: Days
• US Class Current: 333/200
• CPC Class Codes: H03H 2009/02299 Comb-like, i.e. the beam comprising a plurality of fingers or protrusions along its length
• CPC Class Codes: H03H 2009/02307 Dog-bone-like structure, i.e. the elongated part of the "bone" is doubly clamped
• CPC Class Codes: H03H 2009/0233 comprising perforations
• CPC Class Codes: H03H 2009/02472 Stiction
• CPC Class Codes: H03H 2009/02511 Vertical, i.e. perpendicular to the substrate plane
• CPC Class Codes: H03H 2009/02519 Torsional
• CPC Class Codes: H03H 3/0072 of microelectro-mechanical resonators or networks micromembranes or microbeams B81B2203/01; manufacture of microstructural devices in general B81C
• CPC Class Codes: H03H 3/0076 for obtaining desired frequency or temperature coefficients
• CPC Class Codes: H03H 9/02409 by application of a DC-bias voltage H03H9/02417 takes precedence
• CPC Class Codes: H03H 9/2457 Clamped-free beam resonators
• CPC Class Codes: H03H 9/2463 Clamped-clamped beam resonators

Abstract

A microelectromechanical systems (MEMS) device includes a tuning electrode, a drive electrode, and a resonator. The resonator is anchored to a substrate and is configured to resonate in response to a signal on the drive electrode. The MEMS device includes a tuning plate coupled to the resonator and positioned above the tuning electrode. The tuning plate is configured to adjust a resonant frequency of the resonator in response to a voltage difference between the resonator and the tuning electrode. In at least one embodiment of the MEMS device, the tuning plate and the tuning electrode are configured to adjust the resonant frequency of the resonator substantially independent of the signal on the drive electrode.

Claims

1. A microelectromechanical systems (MEMS) device comprising:

a tuning electrode;

a drive electrode;

a resonator anchored to a substrate and configured to resonate in response to a signal on the drive electrode; and

a tuning plate coupled to the resonator and positioned above the tuning electrode, the tuning plate being configured to adjust a resonant frequency of the resonator in response to a voltage difference between the resonator and the tuning electrode.

2. The MEMS device, as recited in claim 1, wherein the tuning plate and the tuning electrode are configured to adjust the resonant frequency of the resonator substantially independent of the signal on the drive electrode.

3. The MEMS device, as recited in claim 1, wherein the tuning electrode is embedded in the substrate below a plane of the drive electrode.

4. The MEMS device, as recited in claim 1, wherein the resonator further comprises:

a sense electrode configured to detect a response based on the resonance of the resonator.

5. The MEMS device, as recited in claim 1, wherein the resonator further comprises:

a central beam; and

an anchor, wherein the tuning plate is positioned at a first end of the central beam, opposite the anchor.

6. The MEMS device, as recited in claim 1, wherein the resonator further comprises:

a central beam; and

a lattice portion positioned at a first end of the central beam, the lattice portion forming a perimeter around the drive electrode.

7. The MEMS device, as recited in claim 6, wherein the central beam extends between the first end and a second end and is anchored at approximately a midpoint of the central beam.

8. The MEMS device, as recited in claim 6, wherein the central beam comprises:

a first material with a first Young'"'"'s modulus dependence on temperature; and

a second material with a second Young'"'"'s modulus dependence on temperature.

9. The MEMS device, as recited in claim 1, wherein the resonator includes a first portion statically deflected out-of-plane.

10. The MEMS device, as recited in claim 1, the resonator being configured to resonate in an out-of-plane mode.

11. The MEMS device, as recited in claim 1, wherein the resonator has a strain gradient statically deflecting the resonator in a direction substantially parallel with a direction of dynamic displacement.

12. A method of operating a microelectromechanical systems (MEMS) resonator, the method comprising:

causing a resonator to resonate by providing a drive electrode with a signal; and

tuning a resonant frequency of the resonator by applying a voltage difference between a tuning electrode and the resonator.

13. The method, as recited in claim 12, wherein a tuning plate and the tuning electrode are configured to adjust the resonant frequency of the resonator substantially independent of a signal on the drive electrode.

14. The method, as recited in claim 12, wherein a drive capacitance established by the drive electrode is substantially linear with dynamic displacement of the resonator.

15. The method, as recited in claim 12, wherein the resonator includes a strain gradient statically deflecting the resonator in a direction substantially parallel with the direction of dynamic displacement.

16. The method, as recited in claim 12, further comprising:

detecting, with a sense electrode, a response based on the resonance of the resonator.

17. The method, as recited in claim 12, wherein the resonator is driven to resonate in a direction normal to a substrate to which the resonator is anchored.

18. A microelectromechanical systems (MEMS) device comprising:

a resonator anchored to a substrate, the resonator comprising;

a first beam anchored to the substrate; and

first and second released portions on opposing sides of a width of the beam, the resonator being configured to undergo a torsional deformation about an axis extending through a length of the beam in response to a drive signal.

19. The MEMS device, as recited in claim 18, wherein the first and second released portions comprise first and second lattice portions, respectively.

20. The MEMS device, as recited in claim 19, further comprising:

a secondary beam attached to the first beam, the secondary beam being configured to couple the first and second lattice portions to each other.

21. The MEMS device, as recited in claim 19, further comprising:

a first electrode anchored to the substrate,

wherein the first lattice portion includes a first lattice opening that forms a perimeter around the first electrode.

22. The MEMS device, as recited in claim 20, wherein the secondary beam comprises first and second cantilever tips configured to be dynamically deflected in response to an out-of-plane electrostatic force on the first and second lattice portions in response to a drive signal.

23. The MEMS device, as recited in claim 19, wherein the first lattice portion has a length and a width and the first lattice portion has a static deflection out-of-plane along the length and a static deflection out-of-plane along the width.