Controlled Thermophoresis as an Actuation Mechanism for Noncantilevered MEMS Devices

A microelectromechanical system actuator based on thermophoretic, or Knudson, forces is proposed using analytical calculations. It can potentially execute scanning or spinning motions of a body that is not mechanically attached to the reference substrate. For a silicon device of 100-mum diameter, it is calculated that it can be levitated at a distance of about 0.5 mum from a substrate and that it can execute scanning motion and use quasi-springs by laterally acting thermal forces. In this way, an engine with spinning motion of a floating body having a diameter of 200 mum with up to 5 kHz can be achieved.