Optimization of Dielectric Material Stoichiometry for High-Reliability Capacitive MEMS Switches

This letter examines the effect of dielectric material stoichiometry and substrate temperature on the charging performance and reliability of capacitive MEMS switches with silicon nitride. Various dielectric stoichiometries were obtained by varying the deposition temperature and gas flow ratios during the PECVD deposition process. Results from both MIM capacitors and MEMS switches have shown that charging is mitigated in silicon nitride films deposited at 150 °C with a high ratio of nitrogen to silicon content (N/Si = 0.98).