Suspended passive element for MEMS devices
A technique decouples a MEMS device from sources of strain by forming a MEMS structure with suspended electrodes that are mechanically anchored in a manner that reduces or eliminates transfer of strain from the substrate into the structure, or transfers strain to electrodes and body so that a transducer is strain-tolerant. The technique includes using an electrically insulating material embedded in a conductive structural material for mechanical coupling and electrical isolation. An apparatus includes a MEMS device including a first electrode and a second electrode, and a body suspended from a substrate of the MEMS device. The body and the first electrode form a first electrostatic transducer. The body and the second electrode form a second electrostatic transducer. The apparatus includes a suspended passive element mechanically coupled to the body and electrically isolated from the body.
1. An apparatus comprising:
a microelectromechanical system (MEMS) device comprising:
a first electrode and a second electrode; and
a body suspended from a substrate of the MEMS device, the body and the first electrode forming a first electrostatic transducer, and the body and the second electrode forming a second electrostatic transducer; and
a suspended passive element mechanically coupled to the body and electrically isolated from the body.
2. The apparatus, as recited in claim 1 , wherein the suspended passive element is a suspended resistor comprising a serpentine structural material portion attached to electrically insulating material portions.
3. The apparatus, as recited in claim 2 , further comprising:
a circuit comprising the suspended resistor, the circuit being configured to detect a temperature change of the MEMS device.
4. The apparatus, as recited in claim 2 , further comprising:
a circuit comprising the suspended resistor, the circuit being configured to adjust a temperature of the MEMS device.
5. The apparatus, as recited in claim 1 , wherein the suspended passive element is mechanically coupled to a central beam of the body.
6. The apparatus, as recited in claim 1 , wherein the suspended passive element is a suspended inductor mechanically coupled to the body and electrically isolated from the body.
7. The apparatus, as recited in claim 6 , wherein the suspended inductor comprises a planar spiral structural material portion attached to electrically insulating material portions.
8. The apparatus, as recited in claim 1 , wherein the suspended passive element is electrically conductive and electrically isolated from the first and second electrodes.
9. A method of manufacturing an apparatus comprising:
forming a microelectromechanical system (MEMS) device comprising:
a first electrode and a second electrode; and
a body suspended from a substrate of the MEMS device, the body and the first electrode forming a first electrostatic transducer, and the body and the second electrode forming a second electrostatic transducer; and
forming a suspended passive element mechanically coupled to the body and electrically isolated from the body.
10. The method, as recited in claim 9 , wherein the suspended passive element is a suspended resistor comprising a serpentine structural material portion attached to electrically insulating material portions.
11. The method, as recited in claim 9 ,
wherein forming the MEMS device comprises forming a structural layer using the substrate; and
wherein forming the suspended passive element comprises forming electrical insulator material embedded in the structural layer.
12. The method, as recited in claim 11 , wherein forming the suspended passive element comprises releasing the structural layer.
13. The method, as recited in claim 9 , further comprising:
forming a circuit portion, the circuit portion being configured to detect a temperature change of the MEMS device using the suspended passive element.
14. The method, as recited in claim 9 , further comprising:
forming a circuit portion, the circuit portion being configured to adjust a temperature of the MEMS device using the suspended passive element.
15. The method, as recited in claim 9 , wherein the suspended passive element is a suspended inductor mechanically coupled to the body and electrically isolated from the body.
16. The method, as recited in claim 9 , wherein the suspended passive element is mechanically coupled to a central beam of the body.
17. The method, as recited in claim 9 , wherein the suspended passive element is formed from a structural material having a low resistivity.
18. The method, as recited in claim 9 , wherein the suspended inductor comprises a planar spiral structural material portion attached to electrically insulating material portions.
19. An apparatus comprising:
means for vibrating, wherein the means for vibrating is suspended from a substrate;
means for electrostatically driving the means for vibrating;
means for electrostatically sensing vibrations of the means for vibrating; and
means for passively transferring energy from a first node to a second node, the means for passively transferring energy being suspended from the substrate and being mechanically coupled to and electrically isolated from the means for vibrating.
20. The apparatus, as recited in claim 19 , wherein the means for passively transferring energy comprises:
means for heating the means for vibrating, wherein the means for heating is suspended from the substrate; and
means for mechanically coupling and electrically isolating the means for vibrating to the means for heating.
21. The apparatus, as recited in claim 19 , wherein the means for passively transferring energy comprises:
means for sensing temperature variations of the means for vibrating, wherein the means for sensing temperature variations is suspended from the substrate; and
means for mechanically coupling and electrically isolating the means for vibrating to the means for sensing temperature variations.