Lateral Flexure Contact on CMOS MEMS Electrothermal Metal-Metal Contact Switch by Platinum ALD Sidewall Patterning

A CMOS MEMS lateral electrothermal switch with flexural metal-metal contact is demonstrated by using metal atomic-layer-deposition (ALD) sidewall patterning. The multilayer electrothermal actuators close/open the switch gap by a combination of self-assembly and thermal actuation forces. The thermal isolation structure is designed to confine the joule heating in the actuator area. Nine different configurations of tip geometries and contact springs with metal-coated sidewalls in the normally-closed and normally-open devices are fabricated and studied. The results show a higher resistance reduction rate (~2x higher) under forces in spring contacts compared to the rigid contacts, indicating the potential to improve the performance through contact spring design.