Micromachined Thermal Multimorph Actuators Fabricated by Bulk-etched MUMPs 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 micromanipulation and nanoposition such as manipulation of scanning tunneling microscope (STM) tips, nanopositioner for nano-assembly, micro/nanorobots and cantilever-based nanosensors. The actuator consists of a multilayer micromachined beam constructed of various combinations of polysilicon, oxide and metal layers. The multimorph is heat by applying current to an embedded polysilicon wire to achieve beam bending The maximum tip deflection of 2.5 m 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.