Simplified RF-MEMS Switches Using Implanted Conductors and Thermal Oxide

This paper presents microwave capacitive RF-MEMS switches based on a novel simplified fabrication process. The devices are fabricated on a silicon substrate using only one metallisation layer. For the capacitive coupling of the switch, an implanted conductive region and thermally grown silicon oxide is used instead of a second metal layer and an additional dielectric layer. In addition, the formerly used bimorph metallisation layer is replaced by a single-metallisation concept, which results in an increased temperature range of operation. The simplified process as well as the switch topology used lead to high performance and highly reliable RF-MEMS switches. RF-measurement results are presented of Ku- and K-band series switches and a Ka-band parallel switch with low insertion losses between -0.2dB and -0.3dB and isolation of e.g. -17dB at 30GHz