The influence of the package environment on the functioning and reliability of RF-MEMS switches

This paper discusses the influence of pressure and gas inside a package on the functioning and lifetime of capacitive RF-MEMS switches. It is shown that decreasing the pressure strongly influences the switching speed of a switch, but if it becomes too low it causes anomalous vibration effects. When testing at the same pressure, it is shown that the lifetime of the capacitive switches is higher in a nitrogen environment than in ambient air (lab) environment. These effects are attributed to the humidity of the air and its influence on charge trapping in the insulator, resulting in stiction of the switch bridge. It is also shown that this charge is not stable and that the switch recovers when it is not actuated.