Dielectric Charging Asymmetry in SiN Films Used in RF MEMS Capacitive Switches

This paper presents a systematic investigation of the effect of stressing bias polarity to the discharge process of plasma enhanced chemical vapor deposition SiN films that have been fabricated under different deposition conditions. Dielectric charging asymmetry has been observed on the utilized films of metal-insulator-metal capacitors and microelectromechanical systems capacitive switches, since charging is enhanced when negative polarization bias is applied to the top electrode. In addition, it is shown that deposition conditions play a key issue role on the degree of this asymmetry. Finally, a physical model which assumes that hopping dominates the discharging process is used in order to gain a better understanding of the processes that are responsible for the appearance of asymmetric dielectric charging and the results correlate with the material's electrical properties.