Micromechanical resonator device and micromechanical device utilizing same

• US 6,856,217 B1
• Filed: 09/11/2003
• Issued: 02/15/2005
• Est. Priority Date: 08/24/2000
• Status: Expired due to Term

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Clark, John R., Nguyen, Clark T.-C.
• Primary Examiner(s): Summons, Barbara
• Application Number:
  US10/660,332
• Time in Patent Office: 523 Days
• Field of Search: 333186-192, 333197-199, 310/309
• US Class Current: 333/186
• CPC Class Codes: H03H 2009/02496 Horizontal, i.e. parallel to the substrate plane
• CPC Class Codes: H03H 2009/02503 Breath-like, e.g. Lam? mode, wine-glass mode
• CPC Class Codes: H03H 2009/02527 Combined
• CPC Class Codes: H03H 3/007 for the manufacture of electromechanical resonators or networks
• 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 3/013 for obtaining desired frequency or temperature coefficient H03H3/0076 H03H3/04, H03H3/10 take precedence
• CPC Class Codes: H03H 9/02362 Folded-flexure
• CPC Class Codes: H03H 9/2436 Disk resonators
• CPC Class Codes: H03H 9/46 Filters multiple-port electromechanical filters H03H9/70
• CPC Class Codes: H03H 9/462 Microelectro-mechanical filters
• CPC Class Codes: H03H 9/505 for microelectro-mechanical filters

Abstract

A micromechanical resonator device and a micromechanical device utilizing same are disclosed based upon a radially or laterally vibrating disk structure and capable of vibrating at frequencies well past the GHz range. The center of the disk is a nodal point, so when the disk resonator is supported at its center, anchor dissipation to the substrate is minimized, allowing this design to retain high-Q at high frequency. In addition, this design retains high stiffness at high frequencies and so maximizes dynamic range. Furthermore, the sidewall surface area of this disk resonator is often larger than that attainable in previous flexural-mode resonator designs, allowing this disk design to achieve a smaller series motional resistance than its counterparts when using capacitive (or electrostatic) transduction at a given frequency. Capacitive detection is not required in this design, and piezoelectric, magnetostrictive, etc. detection are also possible. The frequency and dynamic range attainable by this resonator makes it applicable to high-Q RF filtering and oscillator applications in a wide variety of communication systems. Its size also makes it particularly suited for portable, wireless applications, where, if used in large numbers, such a resonator can greatly lower the power consumption, increase robustness, and extend the range of application of high performance wireless transceivers.

Claims

1. A micromechanical resonator device having at least one mode shape, the device comprising:

a substrate;

a resonator disposed above the substrate and having a disk-shaped surface wherein the at least one mode shape involves axial, flexural or contour modification of the disk-shaped surface at resonance; and

a support structure anchored to the substrate to support the resonator above the substrate wherein both the resonator and the support structure are dimensioned and positioned relative to one another so that the resonator is substantially isolated during vibration thereof wherein energy losses to the substrate are substantially eliminated and wherein the resonator device is a high-Q resonator device.

2. The device as claimed in claim 1, wherein the resonator is supported above the substrate at one or more discrete locations on the resonator.

3. The device as claimed in claim 1, wherein the support structure includes an anchor that supports the resonator above the substrate.

4. The device as claimed in claim 3, wherein the support structure includes a further anchor.

5. The device as claimed in claim 3, wherein the resonator is center-anchored to the substrate by the anchor.

6. A micromechanical resonator device having at least one mode shape, the device comprising:

a substrate;

a resonator disposed above the substrate and having a disk-shaped surface wherein the at least one mode shape involves axial, flexural or contour modification of the disk-shaped surface at resonance; and

a drive electrode structure formed on the substrate at a position to allow electrostatic excitation of the resonator so that the resonator is driven in the at least one mode shape wherein the resonator and the drive electrode structure define a capacitive gap therebetween and wherein the capacitive gap is a sub-micron, lateral, capacitive gap.

7. A micromechanical resonator device having at least one mode shape, the device comprising:

a substrate;

a resonator disposed above the substrate and having at least one nodal point;

a disk-shaped surface wherein the at least one mode shape involves axial, flexural or contour modification of the disk-shaped surface at resonance wherein the at least one nodal point corresponds to a center of the resonator; and

a support structure to support the resonator wherein the support structure is a single anchor positioned at the center of the resonator.

8. A micromechanical resonator device having at least one mode shape, the device comprising:

a substrate;

a resonator disposed above the substrate and having a disk-shaped surface wherein the at least one mode shape involves axial, flexural or contour modification of the disk-shaped surface at resonance; and

a drive electrode structure formed on the substrate at a position to allow electrostatic excitation of the resonator so that the resonator is driven in the at least one mode shape wherein the resonator and the drive electrode structure define a capacitive gap therebetween and wherein the drive electrode structure is positioned beneath the resonator and wherein the at least one mode shape includes a flexural mode shape.

9. A micromechanical resonator device having at least one mode shape, the device comprising:

a substrate; and

a resonator disposed above the substrate and having a disk-shaped surface wherein the at least one mode shape involves axial, flexural or contour modification of the disk-shaped surface at resonance and wherein the device is diamond-based.

10. The device as claimed in claim 9, further comprising a support structure anchored to the substrate to support the resonator above the substrate wherein both the resonator and the support structure are dimensioned and positioned relative to one another so that the resonator is substantially isolated during vibration thereof wherein energy losses to the substrate are substantially eliminated and wherein the resonator device is a high-Q resonator device.

11. The device as claimed in claim 9, wherein the at least one mode shape includes a radial-contour mode shape.

12. The device as claimed in claim 9, wherein the at least one mode shape includes a flexural mode shape.

13. The device as claimed in claim 9, further comprising a drive electrode structure formed on the substrate at a position to allow electrostatic excitation of the resonator so that the resonator is driven in the at least one mode shape and wherein the resonator and the drive electrode structure define a capacitive gap therebetween.

14. The device as claimed in claim 13, wherein the drive electrode structure is disposed about a periphery of the resonator and wherein the at least one mode shape includes a radial-contour mode shape.

15. The device as claimed in claim 14, wherein the drive electrode structure includes a plurality of split electrodes.

16. The device as claimed in claim 13, further comprising a sense electrode structure formed on the substrate at a position to sense output current based on motion of the resonator.

17. The device as claimed in claim 16, wherein the drive electrode structure includes a plurality of separate input drive electrodes and the sense electrode structure includes a plurality of separate output sense electrodes.

18. A micromechanical device comprising:

a substrate;

an input resonator disposed above the substrate and having at least one mode shape and a disk-shaped surface;

an output resonator disposed above the substrate and coupled to the input resonator and having at least one mode shape and a disk-shaped surface wherein the at least one mode shape of at least one of the resonators involves axial, flexural or contour modification of the disk-shaped surface at resonance; and

a coupling spring for mechanically coupling the resonators together.

19. The device as claimed in claim 18, further comprising support structures anchored to the substrate to support the input and output resonators above the substrate.

20. The device as claimed in claim 18, wherein the micromechanical device is a filter.

21. The device as claimed in claim 18, wherein the device is a bandpass filter.

22. The device as claimed in claim 18, further comprising a drive electrode structure formed on the substrate at a position to allow electrostatic excitation of the input resonator and a sense electrode structure formed on the substrate at a position to sense output current based on motion of the output resonator.

23. A micromechanical device comprising:

a substrate;

an input resonator disposed above the substrate and having at least one mode shape and a disk-shaped surface;

an output resonator disposed above the substrate and coupled to the input resonator and having at least one mode shape and a disk-shaped surface wherein the at least one mode shape of at least one of the resonators involves axial, flexural or contour modification of the disk-shaped surface at resonance;

an intermediate resonator disposed above the substrate and coupled to the input and output resonators and having at least one mode shape;

a drive electrode structure formed on the substrate at a position to allow electrostatic excitation of the input resonator;

a sense electrode structure formed on the substrate at a position to sense output current based on motion of the output resonator; and

an intermediate electrode structure formed on the substrate at a position for enhanced access to a response of the device.

24. A micromechanical device comprising:

a substrate;

an input resonator disposed above the substrate and having at least one mode shape and a disk-shaped surface; and

an output resonator disposed above the substrate and coupled to the input resonator and having at least one mode shape and a disk-shaped surface wherein the at least one mode shape of at least one of the resonators involves axial, flexural or contour modification of the disk-shaped surface at resonance and wherein the device is a mixer.

25. A micromechanical resonator device having at least one mode shape, the device comprising:

a substrate;

a resonator disposed above the substrate and having a disk-shaped surface wherein the at least one mode shape involves axial, flexural or contour modification of the disk-shaped surface at resonance, the resonator having at least one anti-nodal portion where the resonator experiences the most displacement when driven;

sensing means for sensing motion of the anti-nodal portion, the sensing means including at least one projection projecting from the anti-nodal portion to move therewith; and

means coupled to the at least one projection to provide an output representation of motion of the anti-nodal portion.

26. The device as claimed in claim 25, wherein the means includes at least one electrode structure.

27. A micromechanical resonator device having at least one mode shape, the device comprising:

a substrate;

a resonator disposed above the substrate and having at least one mode shape and a disk-shaped surface wherein the at least one mode shape involves axial, flexural or contour modification of the disk-shaped surface at resonance; and

a single electrode structure formed on the substrate at a position to allow electrostatic excitation of the resonator and to sense output current based on motion of the resonator.

28. A micromechanical resonator device having at least one mode shape, the device comprising:

a substrate; and

a resonator disposed above the substrate and having a disk-shaped surface wherein the at least one mode shape includes a wine-glass mode that involves modification of the disk-shaped surface at resonance.