Development of Piezoelectric RF MEMS Switch and Phase Shifter

Piezoelectric materials offer unique material characteristics, where elastic deformation is induced by electric field stimulation. These novel material properties can be exploited to create RF MEMS switches and phase shifters with the added benefit of low voltage actuation, reduced power consumption, low cost, and improved reliability with larger contact force and bi-directionality. A novel design for a RF phase shifter has been created for military applications. AMRDEC has developed bond and etch processes, analyzed material combinations and performed extensive test and evaluation of both coplanar waveguides and RF actuators. Significant effort has gone into reducing stress in the structural layers to prevent excessive deformation in switch structures. Improvements in post-release residual stress can be realized by eliminating thermal oxide layers and employing deep silicon etches from the backside for release. Test results indicate that low voltage (~10 V) actuation is achievable.