Mems rf-switch with controlled contact landing

Abstract

A MEMS switch contains an RF electrode, pull-down electrodesand anchor electrodeslocated on a substrate. A plurality of islandsare provided in the pull-down electrode and electrically isolated therefrom. On top of the RF electrode is the RF contactto which the MEMS-bridgeforms an ohmic contact in the pulled-down state. The pull-down electrodesare covered with a dielectric layerto avoid a short-circuit between the bridge and the pull-down electrode. Contact stoppersare disposed on the dielectric layerat locations corresponding to the islands, and the resulting gap between the bridge and the dielectric layer in the pulled-down state reduces dielectric charging. In alternative embodiments, the contact stoppers are provide within the dielectric layeror disposed on the islands themselves and under the dielectric layer. The switch provides good controllability of the contact resistance of MEMS switches over a wide voltage operating range.