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

SiN-based micro cantilever actuators with lengths of the order of 1 mm and NdFeB/Ta thin films for actuation were designed, fabricated and characterized. Multilayered thin films of NdFeB and Ta, with total thicknesses of 13 mum and 3 mum, were deposited on 3 mum-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 700 mum) 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.