MEMS actuation

Digital micro actuation

Actuator matrix

Electrostatic bending actuators (NED)

The novel MEMS-based bending actuators developed at Frauhofer IPMS features:

Name: »Nanoscopic Electrostatic Drive« | short: NED

  • V-NED: Enables vertical deflection (out-of-plane movement)
  • L-NED: Enables lateral deflection (in-plane movement)

V-NED Actuator

V-NED actuator
© Fraunhofer IPMS

L-NED Actuator

Functionality

Huge electrostatic forces at moderate control voltages are generated by up to 200 nm thin electrode separations. Due to a suitable electrode topography (V-NED) or geometry (L-NED) the electrostatic forces will be transformed into lateral forces that curve the cantilever:

  • NED being: MEMS-based bending actuators, that work like bimorph actuators (piezoelectric or thermomechanical effect). They are made with surface micromachining (V-NED) or bulk micromachining (L-NED) on or within silicon wafer substrates.
  • Novelty: On the basis of the novel actuation principle the NED deflection are larger than the electrode separation. Therefore large cantilever tip deflections are possible at low control voltages. Our vision is to enable the use of huge electrostatic forces at very small electrode separation for electrostatic actuation.
  • NED actuators feature: Quasi-static, resonant and digital deflections.

Actuators' degrees of freedom

  • Curvature: Due to the NED actuators cylindrical bending a free cantilever tip displacement can be a generated. If the NED actuator is designed as a rotationally symmetric plate – instead of a simple cantilever – a spherical deformation profile can be achieved.
  • Bidirectional: NED actuators can deflect to a positive or a negative direction depending on the electrode topography, respectively geometry. A combination of topographies, respectively geometries or attaching the actuator cells on both side of the bending actuator enables bidirectional deflections.
  • Tilt and linear movement: An elementary tilt movement can be achieved by use of two mechanically coupled NED actuators. If several NED actuators are mechanically linked to a rod micro component a linear movement is furthermore possible.

CMOS compatibility

Enables an electronic integration into the bending actuators and the integration of the NED actuators into CMOS integrated circuits as well.

Perspective: Strong integration of actuators, sensors and electronics within a semiconductor device.

RoHS compatibility

Enables bending actuators that are compliant with RoHS directive and demonstrates an alternative solution for functional ceramics.