Time predictive model of charge accumulation in bulk PECVD dielectric materials used for electrostatic RF MEMS switches

This paper presents an original time predictive model to simulate the drift of the pull-in voltage due to dielectric charging for electrostatic MEMS switches. This model of charge accumulation is based on the characterization of the bulk dielectric properties by I-V sweeps and constant current injections performed on Metal-Insulator-Metal capacitors. The model can be successfully used to compare various dielectric materials, and lead to parametric studies without the need of any fitting parameters. Moreover, the simulated switch lifetime results are very promising as they are consistent with experimental data obtained for electrostatic MEMS switches either made with SiN_x or SiO₂ dielectric materials.