Magnetic Microactuation of Torsional Polysilicon Structures

A microactuator technology utilizing magnetic thin films and polysilicon flexures is applied to torsional micro-structures. These structures are constructed in a batch-fabrication process that combines electroplating with conventional IC-lithography, materials, and equipment. A microactuated mirror made from a 430x130x15 µm 3 nickel-iron plate attached to a pair of 400x2.2x2.2 µm 3 polysilicon torsional beams has been rotated more than 90° οut of the plane of the wafer and actuated with a torque greater than 3.0 nN-m. The torsional flexure structure constrains motion to rotation about a single axis which can be an advantage for a number of microphotonic applications (e.g., beam chopping, scanning, and steering).