Resonator electrode shields
A microelectromechanical system (MEMS) resonator includes a resonant semiconductor structure, drive electrode, sense electrode and electrically conductive shielding structure. The first drive electrode generates a time-varying electrostatic force that causes the resonant semiconductor structure to resonate mechanically, and the first sense electrode generates a timing signal in response to the mechanical resonance of the resonant semiconductor structure. The electrically conductive shielding structure is disposed between the first drive electrode and the first sense electrode to shield the first sense electrode from electric field lines emanating from the first drive electrode.
1. A semiconductor device comprising:
a support element;
a microelectromechanical system (MEMS) resonator, the MEMS resonator comprising a first body and a second body, the first body embodied as a beam and having a flexure portion and an active portion, motion of which is to be sensed, the flexure portion of the first body operatively coupling the active portion to the support element, and the second body also embodied as a beam and having a flexure portion and an active portion, motion of which is to be sensed, the flexure portion of the second beam operatively coupling the active portion of the second beam to the support element, first beam and the second beam being parallel to one another when at rest;
at least one electrode to cause each of the first body and the second body to deflect during operation of the semiconductor device; and
a conductive element to be tied to a predetermined potential, the conductive element disposed between the first body and the second body so as to impede electrostatic coupling between the first body and the second body.
2. The semiconductor device of claim 1 , wherein the predetermined potential is a ground potential.
3. The semiconductor device of claim 1 , wherein the at least one electrode is to provide a time-varying drive signal to the first body to cause the first body to deflect and is to provide a time-varying drive signal to the second body to cause the second body to deflect.
4. The semiconductor device of claim 1 , wherein the MEMS resonator is configured such that the first body and the second body are to be actuated to differential motion during operation of the semiconductor device.
5. The semiconductor device of claim 1 , wherein the conductive element is a first conductive element, and wherein the semiconductor device further comprises a second conductive element to be tied to a predetermined potential, the second conductive element being disposed so as to impede existence of an electrostatic field between the support element and at least one of the first beam and the second beam.
6. The semiconductor device of claim 1 , wherein the conductive element extends between the flexure portion of the first beam and the flexure portion of the second beam to impede existence of an electrostatic field between the flexure portion of the first beam and the flexure portion of the second beam.
7. The semiconductor device of claim 1 , wherein the first body and the second body each comprise doped crystal silicon.
8. A semiconductor device comprising:
a support element;
a microelectromechanical system (MEMS) resonator, the MEMS resonator comprising a first body and a second body, the first body embodied as a beam and having a flexure portion and an active portion, motion of which is to be sensed, the flexure portion of the first body operatively coupling the active portion to the support element, and the second body also embodied as a beam and having a flexure portion and an active portion, motion of which is to be sensed, the flexure portion of the second beam operatively coupling the active portion of the second beam to the support element, first beam and the second beam being parallel to one another when at rest;
at least one electrode to cause each of the first body and the second body to deflect during operation of the semiconductor device, the deflection comprising vibration at a resonant frequency induced by application of a time-varying electronic signal; and
a conductive element to be tied to a ground potential, the conductive element disposed between the first body and the second body so as to impede interference with the resonant frequency arising from existence of an electrostatic coupling between the first body and the second body.
9. The semiconductor device of claim 8 , wherein the MEMS resonator is configured such that the first body and the second body are to be actuated to differential motion during operation of the semiconductor device.
10. The semiconductor device of claim 8 , wherein the conductive element is a first conductive element and the support element comprises a support frame, and wherein the semiconductor device further comprises a second conductive element to be tied to a predetermined potential, the second conductive element being disposed so as to impede existence of an electrostatic field between the support frame and at least one of the first beam and the second beam.
11. The semiconductor device of claim 8 , wherein the conductive element extends between the flexure portion of the first beam and the flexure portion of the second beam to impede existence of an electrostatic field between the flexure portion of the first beam and the flexure portion of the second beam.
12. The semiconductor device of claim 8 , wherein the first body and the second body each comprise doped crystal silicon.
13. A method of fabricating a semiconductor device, the method comprising:
providing a support element;
providing a microelectromechanical system (MEMS) resonator having a first body and a second body, the first body embodied as a beam and having a flexure portion and an active portion, motion of which is to be sensed, the flexure portion of the first body operatively coupling the active portion to the support element, and the second body also embodied as a beam and having a flexure portion and an active portion, motion of which is to be sensed, the flexure portion of the second beam operatively coupling the active portion of the second beam to the support element, first beam and the second beam being parallel to one another when at rest;
providing at least one electrode to cause each of the first body and the second body to deflect during operation of the semiconductor device; and
providing a conductive element to be tied to a predetermined potential, the conductive element disposed between the first body and the second body so as to impede electrostatic coupling between the first body and the second body.
14. The method of claim 13 , wherein the predetermined potential is a ground potential.
15. The method of claim 14 , wherein the method further comprises configuring the at least one electrode such that it is to provide a time-varying drive signal to the first body to cause the first body to deflect and such that it is to provide a time-varying drive signal to the second body to cause the second body to deflect.
16. The method of claim 15 , wherein providing the MES resonator comprises configuring the MEMS resonator such that the first body and the second body are to be actuated to differential motion during operation of the semiconductor device.
17. The method device of claim 14 , wherein the conductive element is a first conductive element and the support element comprises a support frame, and wherein the method further comprises providing a second conductive element to be tied to a predetermined potential and disposing the second conductive element so as to impede existence of an electrostatic field between the support frame and at least one of the first beam and the second beam.
18. The method of claim 14 , wherein the method comprises disposing the conductive element such that it extends between the flexure portion of the first beam and the flexure portion of the second beam, so as to impede existence of an electrostatic field between the flexure portion of the first beam and the flexure portion of the second beam.
19. The method of claim 13 , wherein providing the MEMS resonator comprises forming the first body and the second body to each comprise doped crystal silicon.