Thermal effects on restoring force and dielectric charge density of RF MEMS switch

Along with the emergence of RF MEMS technology, integration of passive components with high Q value and functional components is now possible, providing an opportunity to attain full integration in a CMOS communication system. Among the components in RF MEMS devices, the switch is the critical unit that has the greatest effect on circuit performance. The RF switch is the frontend of the radio frequency circuit that is used for shifting between the signal channels. The MEMS-based switch employs microstructure to achieve the shifting between on-state and off-state. These switches possess very low insertion lose, high isolation, high linearity, miniscule power consumption, and high cut- off frequency. However, stiction caused by dielectric charging effects and humidity is one of the most common types of RF-MEMS failures, hindering the commercial application of RF-MEMS devices.;In this work, we employed ANSYS to simulate the development of compressive and tensile stress as a function of temperature, and obtained a relationship between the stress and the temperature. Based on this result, we can apply a temperature-stress curve to solve for the release voltage, and make predictions of the charge density at different temperatures.;Moreover, we also consider a modification of the dielectric layer geometry, and show that it's possible to obtain a beneficial reduction ratio using a different design of the dielectric layer's profile.