A Stress-Tolerant Temperature-Stable RF MEMS Switched Capacitor

Abstract

We present the design, fabrication, and measurement of an RF MEMS (Radio Frequency Micro-Electromechanical System) switched capacitor that exhibits reduced sensitivity to residual stress and temperature. The device is based on a circularly symmetric geometry with arc-type springs placed between the anchors and suspended beam. This design compensates for the effects of the residual biaxial stress in the beam, resulting in a pull-in voltage slope versus temperature of only -50 mV/ °C from -5 °C to 95 °C. Reducing the device sensitivity to residual stress improves the performance uniformity on a wafer-scale, and from wafer-to-wafer lots.