SOI/elastomer process for energy storage and rapid release

A new SOI/elastomer fabrication process that integrates a soft elastomer in-plane with silicon features has been developed, characterized and demonstrated. The simple three-mask process uses deep reactive ion etching of trenches in a silicon-on-insulator wafer to pattern high-aspect-ratio silicon and elastomer features from 2 mu m to hundreds of micrometers in width. The elastic and adhesive properties of the fabricated elastomer have been characterized. A Young's modulus of 1.4 MPa was measured at moderate strains up to 75%, and nonlinear strain was observed beyond that. The SOI/elastomer process has been used to fabricate micromechanical thrusters to repeatedly store and release 1.3 mu J to propel a 2 mg 1.6 mm by 0.8 mm by 0.45 mm projectile 1.35 cm.