Time and voltage dependence of dielectric charging in RF MEMS capacitive switches

A major issue in the reliability of RF MEMS capacitive switches is charge injection in the dielectric. In this study the authors try to establish the time and voltage dependence of dielectric charging in RF MEMS with silicon nitride as a dielectric. It is shown that the voltage shift of the CV-curve due to injected charge shows a radict dependence over a large time range. By doing measurements on a large number of devices (early development material made at NXP Semiconductors in Nijmegen) the authors further show that the charging rate increases exponentially with the applied stress voltage