VERTICALLY DRIVEN MICROACTUATORS BY ELECTROTHERMAL BUCKLING EFFECTS

Vertically driven microactuators based on electrothermal buckling effe cts have been demonstrated. These microactuators are fabricated by a m odified surface micromachining process that uses undoped polysilicon a s the structural material. The core component of the microactuator is a rectangular plate (300 X 300 X 2 mu m(3)) which is suspended 2 mu m above the silicon substrate and is supported by two anchor legs. The p late is actuated by a resistive hearts that runs across the microactua tor and is defined by a phosphorus drive-in step. Theoretical models, including electrothermal and thermoelastic behavior of microstructures , have been established and simulated. It has been experimentally demo nstrated that these microactuators an capable of creating a maximum ve rtical actuation of 50 mu m Furthermore, a tiny cylindrical copper blo ck, 330 mu m in diameter and 760 mu m m in length, has been successful ly lifted. (C) 1998 Elsevier Science S.A. All rights reserved.