Micromachined thermal multimorph actuators fabricated by multi-users MEMS process

Micromachined thermal multimorph actuators for out-of-plane displacements have been designed and fabricated by multi-users MEMS process (MUMPS) with a post-processing bulk etching step. Micromachined actuators have potential applications in microtransducers such as scanning tunneling microscope (STM) tips, optical scanners, micromirrors and microrobots. The actuator consists of a multilayer micromachined beam constructed of various combinations of polysilicon, oxide and metal layers. Embedded polysilicon wire is used to heat the multimorph to achieve tip deflection. The tip displacement is a function of the actuator design parameters, such as beam material composition, layer thickness and beam length. The maximum tip deflection of 2.5 μm with an input power of 40 mW is achieved. The maximum operating frequency of 2.7 kHz is measured by focus laser reflecting method. A design methodology, device fabrication, and device characterization are presented.