Si3N4 Thin Films Proprerties for RF-MEMS Reliability Investigation

This paper investigate the dielectric charging mechanisms in Si₃N₄ thin films versus different elaboration conditions and different characterization method. Transient currents measurements in PECVD SiNx were performed versus electrical 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. Injection and detection of electrical charges by atomic force microscopy at the nanometer scale can be used for studying the dynamic and the propagation of the deposited charges. This observation coupled to transient currents measurements, and FTIR,-can give rules for the best dielectric choice for this particular application.