A Two-Terminal Bistable Electrothermally Actuated Microswitch

An improved design of an electrothermally actuated two-terminal bistable microswitch is the focus of this paper. The proposed design has bimodal bistability which is obtained by using a pair of arches, a V-beam electrothermal actuator, and a novel initially retracting actuator. All these elements are monolithically integrated in a single planar releasable layer. The salient feature of the design is the usage of only a single pair of electrodes to switch between ON and OFF states, even though there are two actuators. In order to reduce the stress, the two actuators are mechanically decoupled but are electrically coupled to satisfy the two-terminal actuation. The switch design is experimentally verified by realizing on a silicon-on-insulator (SOI) wafer using a single-layer micro-fabrication technique. An actuation voltage of 11.8 V with 200-ms pulse-width, drives the switch from OFF to ON state and a 50-ms pulse of the same voltage across the same terminals, brings it back.