Improvement of MEMS Thermomechanical Actuation Efficiency by Focused Ion Beam-Induced Deposition

In this article, we present a focused ion beam-induced deposition (FIBID) technique to improve the MEMS thermomechanical actuation efficiency by up to 3 orders of magnitude. During experiments, we investigated the thermomechanical actuation performance of silicon on insulator (SOI) cantilevers integrated in 4-sensors based array. The FIBID process was employed to add an extra layer with a different (and homogeneous) thermal expansion coefficient. The FIBID structures were deterministically deposited with the aid of a xenon-plasma focused ion beam (i.e., no stray species in the amorphous carbon pads). This approach enabled the enhancement of actuation efficiency without any changes in structure stiffness. In this way, an increase in the actuation deflection of 2 orders of magnitude was obtained, which was connected with reduction in the structure stiffness pointing to the enhanced force sensitivity.