A novel RF MEMS technological platform

A novel MEMS technological platform for RF passive components, namely RF MEMS switches, tuneable capacitors and high-Q suspended inductors, is reported. The proposed process employs a metal (Al, AlSi or Cu) as active movable layer and amorphous silicon or polycrystalline silicon as sacrificial layers, providing multi-air-gaps. Various types of substrates like bulk silicon and SOI can be used. Full-dry releasing of suspended beams and membranes is performed with SF₆ or XeF₂, with unrivalled yield/reproducibility compared with any other wet etching techniques. The platform is used to validate new MEMS architectures and concepts, such as the suspended-gate MOSFET that can serve as both RF capacitive switches and tuneable RF capacitors.