Understanding and Improving Longevity in RF MEMS Capacitive Switches

摘要

This paper discusses issues relating to the reliability and methods for employing high-cycle life testing in capacitive RF MEMS switches. In order to investigate dielectric charging, transient current spectroscopy is used to characterize and model the ingress and egress of charges within the switch insulating layer providing an efficient, powerful tool to investigate various insulating materials without constructing actual MEMS switches. Additionally, an in-situ monitoring scheme has been developed to observe the dynamic evolution of switch characteristics during life testing. As an alternative to high-cycle life testing, which may require days or weeks of testing, a method for performing accelerated life tests is presented. Various methods for mitigating dielectric charging are presented including: reduced operating voltage, reduced dielectric area, and improved control waveforms. Charging models, accelerated life test results, and high-cycle life test results for state-of-the-art capacitive RF MEMS switches aid in the better understanding of MEMS switch reliability providing direction for improving materials and mechanical designs to increase the operation lifetime of MEMS capacitive switches.