A low frequency electrical test set-up for the reliability assessment of capacitive RF MEMS switches

The reliability and lifetime testing of capacitive RF MEMS switches one by one at the intended signal frequency range (GHz) is very expensive because RF equipment is monopolized for a large amount of time. Testing a statistically significant number of devices in this way is therefore impractical. Furthermore testing the switches in a harsh environment is difficult. We have developed a new, low frequency measurement set-up to address these issues. In this paper, the principle of operation is described, as are measurements revealing the following failure modes of RF MEMS switches: stiction of the bridge of the devices under test due to charging, and breakdown of the dielectric. We also show that the system can be used to monitor other characteristics, such as the rise- and fall-times and incomplete pull-in of the bridge of the switch when actuated.