Tunable Acceleration Microswitches

Snap-through behavior of a buckled microbeam has been investigated and applied for tunable acceleration switches. The present microswitches are tunable in the sense that threshold acceleration levels can be adjusted by inter-electrode bias voltages. A set of microswitches has been designed and fabricated using the SiO2/p+-silicon bimorph beams of three different lengths: 800μm, 900μm, and 1000μm. Initial deflections of the bimorph beams are generated by the residual stress difference in two dissimilar films. Micromechanical properties of beam materials are measured from on-chip test structures. Threshold voltages for an electrostatic snap-through are measured as 32V, 56V, and 76V for each beam length. Tunable ranges of the threshold acceleration have been estimated as 0-14g, 0-35g and 0-47g under the inter-electrode bias voltages ranging from 0V up to 32V, 56V and 76V, respectively.