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 . An integrated circuit comprising:
a first vibrating body of a MEMS resonator;
a second vibrating body of a MEMS resonator;
a first electrode to sense or drive motion of the first vibrating body;
a second electrode to sense or drive motion of the second vibrating body;
at least one conductive element configured so as to impede coupling between the first vibrating body and the second electrode; and
at least one conductive element configured so as to impede coupling between the first electrode and the second vibrating body.
2 . The integrated circuit of claim 1 wherein the integrated circuit further comprises an electrical contact, wherein the at least one conductive element which is configured so as to impede coupling between the first vibrating body and the second electrode comprises a first element, and wherein the electrical contact is electrically coupled to the first element so as to provide a predetermined potential to the first element.
3 . The integrated circuit of claim 2 wherein the predetermined potential is one of a ground potential and a bias voltage.
4 . The integrated circuit of claim 2 wherein a first predetermined one of the first electrode and the second electrode is configured to always act as a drive electrode and wherein a second predetermined one of the first electrode and the second electrode is configured to always act as a sense electrode.
5 . The integrated circuit of claim 2 wherein:
the at least one conductive element which is configured so as to impede coupling between the second vibrating body and the first electrode comprises a second element; and
the electrical contact is also coupled to the second element so as to provide a predetermined potential to the second element.
6 . The integrated circuit of claim 1 wherein:
the first vibrating body is a first beam of a first MEMS resonator and the second vibrating body is a second beam of the first MEMS resonator;
each of the first beam and the second beam has a longitudinal axis, a first end and a second end; and
one or more support structures operatively mount the first end of first beam in a fixed position relative to the first end of the second beam.
7 . The integrated circuit of claim 6 the longitudinal axis of the first beam is parallel to the longitudinal axis of the second beam.
8 . The integrated circuit of claim 1 wherein the integrated circuit further comprises a third electrode and wherein at least two of the first electrode, the second electrode and the third electrode, are to supply a time-varying electrical stimulus so as to cause the first vibrating body to vibrate during operation of the integrated circuit.
9 . The integrated circuit of claim 8 wherein a first element of the at least one element is configured to also impede the existence of coupling between the third electrode and at least one of the first electrode or the second electrode.
10 . The integrated circuit of claim 1 wherein each of the first electrode and the second electrode is formed of doped silicon.
11 . An integrated circuit comprising:
a MEMS resonator having a first vibrating body and a second vibrating body;
a first electrode to sense or drive motion of the first vibrating body;
a second electrode to sense or drive motion of the second vibrating body;
at least one conductive element configured so as to impede coupling between the first vibrating body and the second electrode; and
at least one conductive element configured so as to impede coupling between the first electrode and the second vibrating body.
12 . The integrated circuit of claim 11 wherein the integrated circuit further comprises an electrical contact, wherein the at least one conductive element which is configured so as to impede coupling between the first vibrating body and the second electrode comprises a first element, and wherein the electrical contact is electrically coupled to the first element so as to provide a predetermined potential to the first element.
13 . The integrated circuit of claim 12 wherein the predetermined potential is one of a ground potential and a bias voltage.
14 . The integrated circuit of claim 12 wherein a first predetermined one of the first electrode and the second electrode is configured to always act as a drive electrode and wherein a second predetermined one of the first electrode and the second electrode is configured to always act as a sense electrode.
15 . The integrated circuit of claim 12 wherein:
the at least one conductive element which is configured so as to impede coupling between the second vibrating body and the first electrode comprises a second element; and
wherein the electrical contact is also coupled to the second element so as to provide a predetermined potential to the second element.
16 . The integrated circuit of claim 11 wherein:
the first vibrating body is a first beam of the MEMS resonator and the second vibrating body is a second beam of the MEMS resonator;
each of the first beam and the second beam has a longitudinal axis, a first end and a second end; and
one or more support structures operatively mount the first end of first beam in a fixed position relative to the first end of the second beam.
17 . The integrated circuit of claim 16 the longitudinal axis of the first beam is parallel to the longitudinal axis of the second beam.
18 . The integrated circuit of claim 11 wherein the integrated circuit further comprises a third electrode and wherein at least two of the first electrode, the second electrode and the third electrode, are to supply a time-varying electrical stimulus so as to cause the first vibrating body to vibrate during operation of the integrated circuit.
19 . The integrated circuit of claim 18 wherein a first element of the at least one element is configured to also impede the existence of coupling between the third electrode and at least one of the first electrode or the second electrode.
20 . A method of fabricating an integrated circuit, the method comprising:
fabricating a first vibrating body of a MEMS resonator;
fabricating a second vibrating body of a MEMS resonator;
fabricating a first electrode which is configured to sense or drive motion, during operation of the integrated circuit, of the first vibrating body;
fabricating a second electrode to sense or drive motion, during operation of the integrated circuit, of the second vibrating body;
fabricating at least one conductive element configured so as to impede coupling between the first vibrating body and the second electrode; and
fabricating at least one conductive element configured so as to impede coupling between the first electrode and the second vibrating body.