Reliability of Suspended Bridges on Superconducting Microstrip Filters Using MEMS Switches

This work proposes to use capacitive micro-electro-mechanical systems (MEMS) switches built on a superconducting microstrip hairpin filter to investigate the reliability of MEMS for long term survivability. This device is made of a YBa₂Cu₃O₇ thin film deposited on a 20 mm × 20 mm LaAlO₃ substrate by pulsed laser deposition and BaTiO₃ by RF magnetron sputtering, which is utilized as a dielectric insulation layer at the switching points of contact. The major concern for capacitive MEMS switches is stiction between the gold suspended bridge membrane (top layer) and the dielectric material (bottom layer). The main failure mode results from charge build-up at the bottom layer which in turn depends on the actuation voltage. The actuation voltage measured at room and cryogenic temperature is used to derive and calculate the Young´s modulus formula which takes into consideration the device geometry, residual stress and mechanical properties of the device. Modified Young´s modulus equation will be validated through reliability data of membrane actuation and failure mode. This equation will in turn be used in modeling other RF MEMS devices operating at cryogenic temperatures.