Study of Dynamics in Metallic MEMS Cantilevers—Pull-In Voltage and Actuation Speed

Abstract

For different metals and varying geometries, this paper presents simulations of electrostatically actuated MEMS cantilevers regarding their influence on pull-in voltage and actuation speed. Three-dimensional electromechanical modeling including many non-linearities has been performed to study some static but mainly dynamic features. The results show that the involved parameters have different influences on the actuation speed and pull-in voltage: lower length, higher thickness as well as lower density and higher Young’s modulus of material diminish the actuation time, while longer length, smaller thickness, and smaller Young’s modulus reduce the actuation voltages. Shorter actuation times and smaller actuation voltages cannot be obtained and optimized simultaneously. Different metals such as Au, Ag, Cu, Ti, Ni, Al, W, Cr, Ta, and Mo as well as artificial metals are studied and compared. In this study, Al is found to be the best material for achieving shorter actuation times and smaller actuation voltages. The design rules of MEMS cantilevers are derived considering the large variety of studied parameters. Many involved non-linearities are discussed in detail influencing the MEMS dynamics. Finally, the actuation times are related to the existing experimental actuation times of optical MEMS shutters and MEMS cantilevers.

State-of-the-Art Materials Used in MEMS Micromirror Arrays for Photonic Applications

“…The measurement presents the highest closing speed of our microshutter arrays measured up to now. In this case, the dimensions of a single microshutter are 2000 µm × 40 µm (Lx and Ly) and the step voltage profile switches from 0 V to 80 V. Our simulations have shown that by reducing the microshutter dimensions (Ly) perpendicular to the hinge, the switching time decreases [51]. However, the height of the actuation voltage also impacts the closing time of the microshutter arrays.…”

“…However, the height of the actuation voltage also impacts the closing time of the microshutter arrays. Very low actuation voltages and fast closing cannot be obtained at the same time [51]. A compromise must be found.…”

“…Despite the concentric arrangement of shutter elements resulting in variations in shape and size, the ring-shaped array shows convincing homogeneity in the opening angle, as depicted in Figure 15a, for size parameters of angular width L φ = 150-600 µm and radial length L r = 60-300 µm. To match future application requirements, the design is adapted according to expected device properties [51]. Figure 15b shows an example of a promising design with an adjusted aspect ratio L r /L φ = 1, also leading to well-planarized shutters.…”

Dynamic Response of Paper-Based Bi-Material Cantilever Actuator

“…For instance, Rasid et al conducted in-depth dynamic modeling of micro-lens actuators, emphasizing the need for intricate modeling in designing cantileverbased devices [17]. Yang et al's studies on the modeling and nonlinear dynamics of various cantilever actuators offer perspectives on device behavior under different scenarios, paving the way for design optimization [18]. Lee et al emphasized the critical role of material properties in cantilever-based devices by employing a quasi-static theoretical framework and corroborating their model through quantitative experimental data [19].…”

A Novel MEMS Actuator Driven with a Low DC Voltage

“…Several studies have been conducted over two decades to solve this problem, (14)(15)(16)(17)(18)(19)(20)(21)(22)(23) however none of them has achieved a displacement larger than 6 μm at a dc driving voltage typically used in MCU boards. We have focused on this matter and proposed a revolutionary structure that overthrows the conventional structures of electrostatic microactuators, which were considered to be unable to drive large amounts of displacement.…”