Vertically driven microactuators by electrothermal buckling effects

Vertically driven microactuators based on electrothermal buckling effects have been demonstrated. These microactuators are fabricated by a modified surface micromachining process that uses undoped polysilicon as 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 plate is actuated by a resistive hearts that runs across the microactuator 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 demonstrated that these microactuators an capable of creating a maximum vertical actuation of 50 mu m Furthermore, a tiny cylindrical copper block, 330 mu m in diameter and 760 mu m m in length, has been successfully lifted. (C) 1998 Elsevier Science S.A. All rights reserved.