Contactless Dielectric Charging Mechanisms in RF-MEMS Capacitive Switches

This paper investigates the possible dielectric layer polarization mechanisms, which contribute to intrinsic charging effects in capacitive RF MEMS switches. The MEMS switches are operated bellow instability point in order to avoid charge injection, hence to allow the dielectric charging to be induced by dipolar or space charge polarization. The possible contribution of interface charge polarization is also examined. The possibility of separating these mechanisms is investigated. Finally it is demonstrated that these polarization mechanisms are responsible for driving a MEMS switch beyond the instability point although the device is biased bellow the pull-in voltage