Piezoelectric on semiconductor-on-insulator microelectromechanical resonators

• US 6,909,221 B2
• Filed: 07/31/2003
• Issued: 06/21/2005
• Est. Priority Date: 08/01/2002
• Status: Active Grant

• Current Assignee: George Tech Research Corporation
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Ho, Gavin Kar-Fai, Humad, Shweta, Piazza, Gianluca, Abdolvand, Reza, Ayazi, Farrokh
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US10/631,948
• Publication Number:
  US 20040021403A1
• Time in Patent Office: 691 Days
• Field of Search: 310/311, 310/312, 310/321, 310/324, 310/328, 310/320, 310/366, 310/322
• US Class Current: 310/321
• CPC Class Codes: H03H 2003/027 the resonators or networks being of the microelectro-mechanical [MEMS] type
• CPC Class Codes: H03H 2009/02196 operating on the FBAR element, e.g. by direct application of a tuning DC voltage
• CPC Class Codes: H03H 3/02 for the manufacture of piezoelectric or electrostrictive resonators or networks H03H3/08 takes precedence

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.

Claims

1. A piezoelectric resonator, including:

a resonating member having a bi-directionally adjustable resonance frequency, said 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;

an electrode;

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.

2. The piezoelectric resonator of claim 1, further including, in response to an excitation force applied to the resonating member, a quality factor for a beam configuration that ranges between approximately 2400-6200 for resonance frequencies ranging between approximately 1.72 megahertz-6.7 mega-hertz.

3. The piezoelectric resonator of claim 1, further including, in response to an excitation force applied to the resonating member, a quality factor for a beam configuration that ranges between approximately 3000-6200 for resonance frequencies ranging between approximately 1.72 megahertz-4.87 mega-hertz.

4. The piezoelectric resonator of claim 1, further including, in response to an excitation force applied to the resonating member, a quality factor for a beam configuration that ranges between approximately 5300-6200 for resonance frequencies ranging between approximately 1.72 megahertz-3.29 mega-hertz.

5. The piezoelectric resonator of claim 1, further including, in response to an excitation force applied to the resonating member, a quality factor for a beam configuration that ranges between approximately 5400-6200 for resonance frequencies ranging between approximately 0.721 megahertz-1.72 mega-hertz.

6. The piezoelectric resonator of claim 1, further including, in response to an excitation force applied to the resonating member, a quality factor for a block configuration that ranges between approximately 5500-11,600 for resonance frequencies ranging between approximately 16.9 megahertz-195 mega-hertz.

7. The piezoelectric resonator of claim 1, further including, in response to an excitation force applied to the resonating member, a quality factor for a block configuration that ranges between approximately 4700-11,600 for resonance frequencies ranging between approximately 16.9 megahertz-195 mega-hertz.

8. The piezoelectric resonator of claim 1, further including, in response to an excitation force applied to the resonating member, a quality factor for a block configuration that ranges between approximately 4500-11,600 for resonance frequencies ranging between approximately 16.9 megahertz-195 mega-hertz.

9. The piezoelectric resonator of claim 1, wherein the semiconductor material, the electrode, and the piezoelectric material are configured in one of a beam configuration and a block configuration.

10. The piezoelectric resonator of claim 1, wherein the electrode includes one of a sense electrode and a drive electrode.

11. The piezoelectric resonator of claim 10, wherein the sense electrode and the drive electrode are separated by the piezoelectric material.

12. The piezoelectric resonator of claim 10, wherein the sense electrode and the drive electrode are separated by the surface of the semiconductor material.

13. The piezoelectric resonator of claim 1, wherein the thickness of the semiconductor material ranges between approximately 0.2-30 microns.

14. The piezoelectric resonator of claim 1, wherein the piezoelectric material includes one of zinc oxide, aluminum nitride, and lead zirconate titanate.

15. The piezoelectric resonator of claim 1, wherein the semiconductor material includes one of silicon, germanium, single crystal semiconductor material, polycrystalline semiconductor material, and amorphous semiconductor material.

16. The piezoelectric resonator of claim 1, further including an adhesion layer disposed between the piezoelectric material and the semiconductor material.

17. The piezoelectric resonator of claim 1, wherein the resonating member includes a resonance frequency resulting from at least one of in-plane and out-of-plane movement of the resonating member.

22. The piezoelectric resonator of claim 1, further including a capacitor created by a second electrode disposed adjacent to the piezoelectric resonator and separated by a gap, wherein the capacitor is configured to receive a direct current voltage to adjust the resonance frequency of the resonating member.

23. The piezoelectric resonator of claim 1, wherein the oxide layer is a thin film layer of a thickness ranging between and including 0.1-5 microns.

18. A communications device, including:

a receiver; and

a piezoelectric resonator disposed in the receiver, the piezoelectric resonator including;

a resonating member having a bi-directionally adjustable resonance frequency, said 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;

an electrode;

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.

19. The communications device of claim 18, wherein the piezoelectric resonator is configured as at least one of a filter and a frequency reference device.

20. The communications device of claim 18, further including a transmitter.

21. The communications device of claim 20, wherein the transmitter includes a second piezoelectric resonator, wherein the second piezoelectric resonator is configured as at least one of a filter and a frequency reference device.