A MEMS thermal actuator is a micromechanical device that typically generates motion by thermal expansion amplification. A small amount of thermal expansion of one part of the device translates to a large amount of deflection of the overall device. Usually fabricated out of doped Single Crystal Silicon or Polysilicon as a complex compliant member, the increase in temperature can be achieved internally by electrical resistive heating or externally by a heat source capable of locally introducing heat. Microfabricated thermal actuators can be integrated into micromotors.