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RI SEMINAR -- Gary K. Fedder


Microelectromechanical systems (MEMS) technology involves the integration of micromechanical structures and electronics to produce a rich variety of sensor and actuator systems. The worldwide market for MEMS is expected to reach $14 billion by the year 2000. Device applications include pressure, tactile and inertial sensors, along with actuators for data storage, optical switching, and fluid control.

One common MEMS fabrication method is polysilicon surface micromachining. Mechanical structures are made from a 2 micron-thick film of polycrystalline silicon that is deposited over a silicon substrate. Surface micromachining is compatible with conventional CMOS processes and several fabrication services that employ surface micromachining are now available. At present, MEMS design is done piecemeal, but more comprehensive CAD tools for surface microsystem design are under development.

An example microsystem, with application to accelerometers and active mirrors, will be described. The microsystem is a testbed for research in multi-mode digital control of MEMS: a suspended polysilicon plate having four capacitive-bridge vertical position sensors, each with an integrated CMOS buffer amplifier, four differential electrostatic feedback actuators on the plate's corners, and an interdigitated comb for lateral force input. The integrated testbed enables the experimental verification of models and simulations of general control strategies for a suspended plate with three degrees of freedom. Test results are obtained using sigma-delta force-balance control at each corner of the plate.

Host:           Yangsheng Xu (xu+@cs.cmu.edu)
Appointment:    Ava Cruse (avac@cs.cmu.edu)

Christopher Lee | chrislee@ri.cmu.edu
Last modified: Wed Dec 7 17:02:32 1994