Piezoelectrically actuated MEMS microswitches for high current applications

In this work the fabrication of a piezoelectrically actuated microswitch for high current applications is proposed. In particular, the microswitch was properly designed to drive currents of the order of 1 A. The device was obtained assembling two silicon substrates: one containing the signal lines and the other enclosing a silicon nitride microcantilever. This latter operates as a switch by closing the circuit with a multilayered metal electrode on its tip. Four layers of lead zirconate titanate (PZT), deposited by sol-gel method, constitute the actuation element of the microcantilever. The bottom and top electrodes of the PZT were respectively made of thin Ti/Pt and Ti/Au layers, deposited by electron beam evaporation. The signal lines and the contact-electrode on the microcantilever tip were made of Ti/Ni/Au/Cu (with a total thickness of about 1 lm). The two substrates were finally bonded together by Au/Sn eutectic bonding.