A Self-Aligned Fabrication Process for Capacitive Fixed-Fixed Beam RF MEMS Components

A self-aligned fabrication process for capacitive fixed-fixed beam RF microelectromechanical system (MEMS) components is disclosed. It enables the scaling of the critical dimensions and reduces the number of processing steps by 40% compared with a conventional RF MEMS fabrication process. RF MEMS varactors with beam lengths of 30μmare demonstrated by using the self-aligned fabrication process, and the performance of a four-by-four RF MEMS varactor bank is discussed as well. At 20 GHz, the measured capacitance values range between 180.5 and 199.2 fF. The measured capacitance ratio is 1.15 when a driving voltage of 35 V is applied, and the measured loadedQ-factor ranges between 14.5 and 10.8. The measured cold-switched power handling is 200 mW.[2008-0018]