Optimization of an amplification mechanism enabling large displacements in MEMS-based nanomaterial testing devices

Abstract

In this paper we report on the optimization of an amplification mechanism to enable large displacements in microelectromechanical systems (MEMS). As a case study, we considered a MEMS-based platform for the mechanical testing of nanomaterials, but the results we obtained can be extended to other devices, too. The studied device consists of a couple of V-shaped thermal actuators, heat sink beams, comb drives for sensing the displacements delivered by the actuators to the sample to be tested, and an amplification stage capable of amplifying the produced displacements to tens of micrometers. Regarding the amplification stage, three different schemes were designed and simulated in order to identify the optimal solution. To this aim, static structural analyses have been carried out to predict the performance of the amplification mechanism with respect to geometrical parameters, such as inclination angle, length or width of the beams embedded in the amplification stage. An amplification factor as large as 50 is found. The numerical results show good agreement with those obtained from analytical models. The performance of the complete device is also evaluated through 3D steady-state static thermal-electrical analyses under variable voltage applied to the actuators. • Different types of amplification mechanisms have been analyzed in order to enable large displacements in MEMS devices. • The mechanism consisting of a V-shaped beam provided the best performance. • The final device was designed as able to deliver a displacement of ~1 μm to the sample, while not overcoming 81 °C.