An isolation technology for joined tungsten MEMS

An isolation technology utilizing a selective chemical vapor deposition (CVD) of tungsten to fabricate released, joined and isolated microelectromechanical structures (MEMS) is presented. The isolation scheme features released tungsten structures that are both mechanically joined and electrically isolated by silicon nitride and offers extra design freedom for micromachining. The technology is used to fabricate an isolated-tungsten, serial-parallel (SP), linear electrostatic, capacitive actuator. The actuator is composed of a series of released silicon nitride hinges. Experiments demonstrate that a controlled large lateral displacement range (e.g., greater than 10 μm) is achieved at modest voltages. Stable stepping motion is a major characteristic of the SP actuator. The fabrication and the operation of this linear actuator are reported