A surface of a cavity of a MEMS device that is rough to reduce stiction. In some embodiments, the average roughness (Ra) of the surface is 5 nm or greater. In some embodiments, the rough surface is formed by forming one or more layers of a rough oxidizable material, then oxidizing the material to form an oxide layer with a rough surface. Another layer is formed over the oxide layer with the rough surface, wherein the roughness of the oxide layer is transferred to the another layer.

A microelectromechanical system (MEMS) device includes a substrate and a movable element at least partially suspended above the substrate and having at least one degree of freedom. The MEMS device further includes a protrusion extending from the substrate and configured to contact the movable element when the movable element moves in the at least one degree of freedom, wherein the protrusion comprises a surface having a water contact angle of higher than about 15? measured in air.

Capped microelectromechanical systems (MEMS) devices are described. In at least some situations, the MEMS device includes one or more masses which move. The cap may include a stopper which damps motion of the one or more movable masses. In at least some situations, the stopper damps motion of one of the masses but not another mass.

A method of the invention includes reducing stiction of a MEMS device by providing a conductive path for electric charge collected on a bump stop formed on a substrate. The bump stop is formed by depositing and patterning a dielectric material on the substrate, and the conductive path is provided by a conductive layer deposited on the bump stop. The conductive layer can also be roughened to reduce stiction.

A microelectromechanical system (MEMS) device includes a substrate and a movable element at least partially suspended above the substrate and having at least one degree of freedom. The MEMS device further includes a protrusion extending from the substrate and configured to contact the movable element when the movable element moves in the at least one degree of freedom, wherein the protrusion comprises a surface having a water contact angle of higher than about 15 measured in air.

The present disclosure provides a CMOS-MEMS device structure. The CMOS-MEMS device structure includes a sensing substrate and a CMOS substrate. The sensing substrate includes a bonding mesa structure. The CMOS substrate includes a top dielectric layer. The sensing substrate and the CMOS substrate are bonded through the bonding mesa structure, and the bonding mesa structure defines a bonding gap between the CMOS substrate and the sensing substrate.

A MEMS switch has fixed support, a plate-shaped flexible beam having at least one end immovably supported by the fixed support and having an extending movable surface, a movable electric contact disposed on the movable surface of the flexible beam, a fixed electric contact facing the movable electric contact and disposed at a fixed position relative to the fixed support, first piezoelectric driver disposed above the movable surface of the flexible beam, extending from a portion above the fixed support towards the movable electric contact, and capable of displacing the movable electric contact towards the fixed electric contact by voltage driving, and second piezoelectric driver disposed at least on the movable surface of the flexible beam and capable of so driving a movable part of the flexible beam by voltage driving that the movable electric contact is separated from the fixed electric contact.

One or more stopper features (e.g., bump structures) are formed in a standard ASIC wafer top passivation layer for preventing MEMS device stiction vertically in integrated devices having a MEMS device capped directly by an ASIC wafer. A TiN coating may be used on the stopper feature(s) for anti-stiction. An electrical potential may be applied to the TiN anti-stiction coating of one or more stopper features.

A MEMS device includes a bottom plate structure supporting a conductive electrode. A flexible conductive top plate movably supported by a flexure is affixed to a small peripheral portion of the top plate that is aligned with the electrode. Drive circuitry applies a high level of a drive voltage signal between the electrode and the top plate to produce an attracting electrostatic force between the top plate and the electrode sufficient to overcome the flexure and draw the top plate against the electrode. The drive circuitry later applies a low level of the drive voltage signal to remove the electrostatic force and allow the flexure to peel the peripheral portion away from the electrode. Additional drive voltage signals may be applied to additional electrodes to draw additional peripheral portions of the top plate against the additional electrodes and successively removed to allow peripheral portions of the top plate to be sequentially peeled away from the electrodes.

The present disclosure provides a CMOS-MEMS device structure. The CMOS-MEMS device structure includes a sensing substrate and a CMOS substrate. The sensing substrate includes a bonding mesa structure. The CMOS substrate includes a top dielectric layer. The sensing substrate and the CMOS substrate are bonded through the bonding mesa structure, and the bonding mesa structure defines a bonding gap between the CMOS substrate and the sensing substrate.