The lifetime prediction and enhancement of RF MEMS switches

Abstract Metal-based cantilever beams in RF microelectromechanical system (MEMS) switches are susceptible to creep under prolonged use, leading to irreversible deformation, pull-in voltage drift, and performance degradation that limit switch lifetime. Given the critical importance of switch lifetime in practical applications, the ability to accurately predict lifetime degradation becomes essential. To meet this need, this work develops a high-fidelity multiphysics finite element method (FEM) framework in COMSOL, coupling electrostatic, structural, and thermally activated creep fields. The model is experimentally validated through high-temperature accelerated creep testing, showing excellent agreement in capturing the time-dependent evolution of pull-in voltage under various thermal conditions, thereby confirming its reliability for predicting lifetime in practical RF MEMS switch. Based on this model, a root-transition optimization strategy is proposed to redistribute stress and suppress creep accumulation. FEM simulation results indicate this design improves lifetime by up to 6.7 times, without altering the device layout or fabrication flow. The proposed modeling and optimization approach provides accurate prediction and practical applicability, and can be broadly applied to other MEMS devices with movable structures, offering a promising solution for future lifetime evaluation and reliability design.