Micro Electro Mechanical Cantilever With Electrostatically Controlled Tip Contact

A micro-electro-mechanical system (MEMS) cantilever that lifts from the surface by electrostatic force is described. The design is composed of three conductors: a fixed buried plate, a fixed surface plate, and a moveable cantilever. All have the same square shape and are arranged parallel in a vertical stack with aligned edges. The surface plate and cantilever are biased at the same potential, and the buried plate is oppositely biased. Theoretical analysis based on values of position-dependent coefficients of capacitance and electrostatic induction from finite element method demonstrates the sign of the force on the cantilever and determines its magnitude. Video microscopy and electrical measurements demonstrate the electrostatic lifting of the cantilever in a fabricated MEMS device. The vertical displacement of the cantilever is quantified from changes in optical interference fringes, and the displacement magnitude agrees with expectations based on estimated strengths of upward electrostatic force and downward elastic restoring force. (C) 2014 AIP Publishing LLC.