Analysis of pull-in voltage of MEMS switches based on material properties and structural parameters

Micro Electro Mechanical Systems (MEMS) Switches have become very popular in the Electronics industry and we need to carefully select beam material and structural parameters for reliability and better performance. A variety of materials can be used as beam material in RF MEMS switches. The cantilever beam is used to change the state of RF switch and for actuation is made mostly using aluminum, copper, gold, molybdenum, nickel and platinum. This paper investigates which is the best material to be used for beam for achieving lower pull-in voltage and also represents the effect of structural parameters such as air gap and beam thickness on the performance of MEMS series switches. Characterization of cantilever MEMS switches is carried out with 3D simulation using COMSOL Multiphysics based on Finite Element Method [FEM]. Reduction of Pull-in voltage can be done by carefully selecting beam material and it can further be reduced by decreasing air gap and beam thickness.