Hybrid approach for RF MEMS devices

A single-crystal silicon DC-40 GHz RF MEMS switch

“…The vast majority of RF MEMS switches today utilize thin-film metals as structural materials in order to decrease the RF loss of these devices. Devices that have attempted to utilize non-metallic structural materials [4], [5], [6], [7], [8] have not been successful due to poor RF performance and/or excessive process complexity that counteracts the advantages offered by single-crystal silicon.…”

Hybrid RF-MEMS Switches Realized in SOI Wafers by Bulk Micromachining

“…The switch capacitance model [29], for a switch at up state, yields a capacitance C t of 6.6 fF between the CPW signal and ground lines for a ground capacitor area of 40 × 150 μm, a signal capacitor area of 20 × 40 μm, and an initial gap of 5 μm. According to the model, the calculated switch metal layer resistance is 0.3 Ω, and the calculated inductance is 0.1 nH.…”

“…RF analytic modeling of the shunt ohmic switch included CPW impedance calculations using conformal mapping models [33], CPW metallic and dielectric loss models [33], and a multilayer parallel-plate capacitance model, including a fringing field model [29]. All these models were combined under a lumped circuit model of a shunt switch.…”

“…In order to estimate the influence of a full package concept on the RF performance of the switch, a dedicated design was fabricated [29]. In this full package design, the handle layer is not etched as described in Step 6 of the fabrication process, but it remains and serves as a cover for the switch.…”