SiN-based micro cantilever actuators using NdFeB/Ta permanent magnetic thin film

SiN-based micro cantilever actuators with lengths of the order of 1mm and NdFeB/Ta thin films for actuation were designed, fabricated and characterized. Multilayered thin films of NdFeB and Ta, with total thicknesses of 13µm and 3µm, were deposited on 3µm-thick SiN cantilevers by magnetron sputtering. The remnant flux density and coercive force of the thin film were as high as those obtained for bulk NdFeB magnets. The SiN based magnetic actuator showed good strength even when undergoing considerable bending. Large bidirectional out-of-plane displacements (up to 700µm) were generated using an air cored coil placed beneath the cantilevers. Static and dynamic evaluations were carried out using a CCD camera and an optical fiber displacement sensor, respectively. The experimentally measured displacements were in agreement with simulated values.