Membrane-based nano-electromechanical systems device and methods to make and use same
Nano-electromechanical systems (NEMS) sensor devices that utilize thin electrically conductive membranes, which can be, for example, graphene membranes. The NEMS devices can have a trough shape (such as a serpentine shape arrangement) of the electrically conductive membrane. The thin, electrically conductive membrane has membrane-structures disposed upon it in an array of cavities. These membrane structures are between the thin, electrically conductive membrane and the main membrane trace. Such an arrangement increases the sensitivity of the NEMS sensor device. The electrically conductive membrane can be controllably wicked down on the edge of the oxide cavity to increase the sensitivity of the NEMS sensor device. Such NEMS sensor devices include NEMS sensor devices that are well suited to applications that measure magnetic fields that, operate below 10 kHz, such as brain-computer interfaces.
1. A nano-electromechanical system sensor device comprising a section that is oriented along a first plane, wherein the section comprises
(a) a thin, electrically conductive membrane having a first end and a second end, wherein
(i) the thin, electrically conductive membrane has a membrane structure deposited on the thin, electrically conductive membrane;
(b) a substrate oriented parallel to the first plane, wherein
(i) the substrate comprises a cavity having a substrate metal trace on the substrate, and
(ii) the thin, electrically conductive membrane is parallel to the first plane, wherein the thin, electrically conductive membrane bounds the cavity;
(c) a first connector electrically connected to the first end of the thin, electrically conductive membrane; and
(d) a second connector electrically connected to the second end of the thin, electrically conductive membrane, such that current is operable to flow through the thin, electrically conductive membrane between the first connector and the second connector causing the thin, electrically conductive membrane facing the cavity to deflect in a direction perpendicular to the first plane in the presence of a magnetic field, wherein
(i) the nano-electromechanical system sensor device is operable to adjust tension of the thin, electrically conductive membrane bounded in the cavity to adjust resonant frequency, and
(ii) the deflection of the thin, electrically conductive membrane in a direction perpendicular to the first plane comprises
(A) a first set of deflections in which the portions of the thin, electrically conductive membrane facing the first portion of the plurality of rows deflect in a direction toward the substrate and the portions of the thin, electrically conductive membrane facing the second portion of rows deflect in a direction away from the substrate, and
(B) a second set of deflections in which the portions of the thin, electrically conductive membrane facing the first portion of the plurality of rows deflect in the direction away from the substrate and the portions of the thin, electrically conductive membrane facing the second portion of rows deflect in the direction toward the substrate.
2. The nano-electromechanical system sensor device of claim 1 , wherein
(a) the substrate comprises a plurality of cavities; and
(b) the thin, electrically conductive membrane bounds the plurality of the cavities and provides for a plurality of portions of the thin, electrically conductive membrane that are bound to the plurality of the cavities.
3. The nano-electromechanical system sensor device of claim 2 , wherein the plurality of cavities are arranged in a plurality of rows.
4. A nano-electromechanical system sensor device comprising a section that is oriented along a first plane, wherein the section comprises
(a) a thin, electrically conductive membrane having a first end and a second end, wherein
(i) the thin, electrically conductive membrane has a membrane structure deposited on the thin, electrically conductive membrane;
(b) a substrate oriented parallel to the first plane, wherein
(i) the substrate comprises a cavity having a substrate metal trace on the substrate, and
(ii) the thin, electrically conductive membrane is parallel to the first plane, wherein the thin, electrically conductive membrane bounds the cavity;
(c) a first connector electrically connected to the first end of the thin, electrically conductive membrane; and
(d) a second connector electrically connected to the second end of the thin, electrically conductive membrane, such that current is operable to flow through the thin, electrically conductive membrane between the first connector and the second connector causing the thin, electrically conductive membrane facing the cavity to deflect in a direction perpendicular to the first plane in the presence of a magnetic field, wherein
(i) the substrate comprises a plurality of cavities,
(ii) the thin, electrically conductive membrane bounds the plurality of the cavities and provides for a plurality of portions of the thin, electrically conductive membrane that are bound to the plurality of the cavities,
(iii) the plurality of cavities are arranged in a plurality of rows,
(iv) the plurality of rows comprises a first portion of the plurality of rows and a second portion of the plurality of rows, and
(v) the deflection of the thin, electrically conductive membrane in a direction perpendicular to the first plane comprises
(A) a first set of deflections in which the portions of the thin, electrically conductive membrane facing the first portion of the plurality of rows deflect in a direction toward the substrate and the portions of the thin, electrically conductive membrane facing the second portion of rows deflect in a direction away from the substrate, and
(B) (ii) a second set of deflections in which the portions of the thin, electrically conductive membrane facing the first portion of the plurality of rows deflect in the direction away from the substrate and the portions of the thin, electrically conductive membrane facing the second portion of rows deflect in the direction toward the substrate.
5. The nano-electromechanical system sensor device of claim 1 , wherein
(a) the substrate has a substrate non-electrically conductive layer; and
(b) the thin, electrically conductive membrane is on the substrate non-electrically conductive layer.
6. The nano-electromechanical system sensor device of claim 1 , wherein the thin, electrically conductive membrane is in a serpentine shape.
7. The nano-electromechanical system sensor device of claim 1 , wherein the membrane structure is within the cavity.
8. The nano-electromechanical system sensor device of claim 1 , wherein the membrane structure comprises an electrically conductive layer that is a main membrane trace.
9. The nano-electromechanical system sensor device of claim 8 further comprising a gap sensor within the cavity, wherein the gap sensor is operable for providing position feedback of the gap between the substrate metal trace and the main membrane trace.
10. The nano-electromechanical system sensor device of claim 8 , wherein the main membrane trace of the thin, electrically conductive membrane faces the substrate metal trace at a gap distance of between 5 nm and 50 nm.
11. The nano-electromechanical system sensor device of claim 1 , wherein the nano-electromechanical system sensor device is operable for measuring a magnetic field operating below 10 kHz.
12. The nano-electromechanical system sensor device of claim 1 , wherein the nano-electromechanical system sensor device is operable to maintain the thin, electrically conductive membrane bounded in the cavity at a pre-determined resonant frequency.
13. The nano-electromechanical system sensor device of claim 1 , wherein the thin, electrically conductive membrane has a thickness of approximately one nm.
14. The nano-electromechanical system sensor device of claim 1 , wherein the thin, electrically conductive membrane has a thickness between 1 nm and 25 nm.
15. The nano-electromechanical system sensor device of claim 1 , wherein the thin, electrically conductive membrane is selected from a group consisting of graphene, graphene oxide, graphene/graphene oxide composites, and electrically conductive polymers.
16. The nano-electromechanical system sensor device of claim 1 , wherein the thin, electrically conductive membrane comprises PDMS coated with an electrically conductive material.
17. The nano-electromechanical system sensor device of claim 1 , wherein
(a) the nano-electromechanical systems device comprises two sections; and
(b) the sections are perpendicular to one another.
18. The nano-electromechanical system sensor device of claim 1 , wherein
(a) the nano-electromechanical systems device comprises three sections; and
(b) the sections are each perpendicular to one another.
19. The nano-electromechanical system sensor device of claim 1 , wherein the nano-electromechanical system sensor device is operable to sense an alternating magnetic field signal.
20. The nano-electromechanical system sensor device of claim 18 , wherein the alternating magnetic field signal is between 1 and 100 femto-tesla.
21. The nano-electromechanical system sensor device of claim 1 , wherein the nano-electromechanical system sensor device is operable to adjust the tension of the thin, electrically conductive membrane to adjust the stiffness of the thin, electrically conductive membrane bounded in the cavity.
22. The nano-electromechanical system sensor device of claim 1 , wherein
(a) the nano-electromechanical system sensor device comprises CMOS circuit, a first electrostatic force trace, and a second electrostatic force trace;
(b) the CMOS circuit is operable to measure resonant frequency of the thin, electrically conductive membrane bounded in the cavity; and
(c) the first electrostatic force trace and the second electrostatic force trace are operable to adjust the resonant frequency to a desired resonant frequency.
23. The nano-electromechanical system sensor device of claim 22 , wherein
(a) the first electrostatic force trace and the second electrostatic force trace are operable to increase the tension of the thin, electrically conductive membrane bounded in the cavity by increasing voltage on the first electrostatic force trace while decreasing voltage on the second electrostatic force trace; and
(b) the first electrostatic force trace and the second electrostatic force trace are operable to decrease the tension of the thin, electrically conductive membrane bounded in the cavity by decreasing voltage on the first electrostatic force trace while increasing voltage on the second electrostatic force trace.
24. The nano-electromechanical system sensor device of claim 1 , wherein the nano-electromechanical system sensor device is operable to adjust the tension of the thin, electrically conductive membrane bounded in the cavity while maintaining a near constant gap between the substrate metal trace and a main membrane trace.