Correlation between Chemical and Electrical Properties of SiNx Deposed by PECVD. Impact on RF MEMS devices

The influence of different dielectrics types on the switching behavior and reliability of capacitive RF MEMS switches, elaborated by PECVD, is investigated. Transient currents measurements in SiNx were made versus field, temperature and time. These results suggest a dominant conduction mechanism and allow to predict the amount of charge injected into the dielectric and the charge/discharging kinetics processes. The deposition parameters effects, evaluated by FTIR, in order to identify the chemical bond in the dielectric, can explain the charging behavior. Good agreement was obtained between transient currents measurements and FTIR.