Reliability of capacitive RF MEMS switches at high and low temperatures

Some applications of RF MEMS switches, such as aircraft condition monitoring and distributed satellite communication, present a unique challenge for device design and reliability. This article examines these switches when operational temperatures in the range -60degreesC to 100degreesC are envisioned. The basic operation of a capacitive MEMS switch is described and two tools for examining device reliability, modeling, and on-chip experimentation, are discussed in the case of capacitive MEMS switches. 1D, 2D, and 3D models are presented with emphasis on 3D coupled-field finite-element analysis, including temperature effects. Results and findings from the 3D simulations are reported. In particular, the advantages of employing corrugated membranes in the design of RF MEMS switches are assessed. Their performance in terms of reliability as a function of temperature is quantified. The effects of corrugation on the geometric parameters are discussed in the context of device-design optimization. In order to assess reliability experimentally, the M-test and the membrane deflection experiment (MDE) are reviewed due to their on-chip characteristic and simplicity. Ways in which these experimental/computational methodologies can be combined for identifying material properties and device performance is also highlighted. (C) 2004 Wiley Periodicals, Inc.