Temperature study of the dielectric polarization effects of capacitive RF MEMS switches

TLDR

This paper investigates the dielectric charging effects of capacitive RF MEMS switches using silicon nitride dielectric, both theoretically and experimentally. The charging mechanism is thermally activated, with activation energy derived from the temperature dependence of the capacitance transient response. Dielectric charging from charge injection under voltage stress was observed, with amphoteric traps influencing operation under both polarities, and the process is best described by a stretched exponential relaxation that also explains pull‑out voltage shifts and temperature‑induced capacitance minimum bias changes.

Abstract

This paper investigates both theoretically and experimentally the dielectric charging effects of capacitive RF microelectromechanical system switches with silicon nitride as dielectric layer. Dielectric charging caused by charge injection under voltage stress was observed. The amphoteric nature of traps and its effect on the switch operation were confirmed under both positive and negative control voltages. It has been confirmed that charging is a complicated process, which can be better described through the stretched exponential relaxation. This mechanism is thermally activated with an activation energy being calculated from the temperature dependence of the capacitance transient response. The charging mechanism, which is responsible for the pull-out voltage and the device failure, is also responsible for the temperature-induced shift of the capacitance minimum bias.