Performance of Molybdenum as a Mechanical Membrane for RF MEMS Switches

Abstract — This article details the construction and measurement of RF MEMS capacitive switches using molybdenum as the mechanical material. The resulting switches exhibit a significantly reduced rate of change in actuation voltage over temperature, with rates less than 0.03 V/°C up to 150°C. Resistivity of the molybdenum membranes averaged 10-11 -cm, yielding an effective shunt resistance of less than 0.25 . Initial cycling measurements were made which show that the resulting membranes were capable of at least 20 billion cycles without failure, indicating that molybdenum is a promising mechanical material for constructing RF MEMS switches. Index Terms — microelectromechanical systems, RF MEMS, MEMS switch, molybdenum, capacitive switch, temperature