A bistable microrelay based on two-segment multimorph cantilever actuators

A surface micromachined bistable microrelay based on the latching of a novel two-segment multimorph cantilever actuator is presented. The two-segment multimorph actuator is composed of two bimorph segment actuators that are connected with each other, one is normally open (NO) and the other is normally closed (NC). The two bimorph segments can be actuated independently in such a way that the device has two stable mechanical latching states, namely, "on" and "off", which can be electrically read out with large off/on resistance ratios. This bistable relay is operated by two separate thermal power pulses at 12 mW and 10 mW respectively. The latching "on" and unlatching "off" operation times are less than 0.5 msec and 0.1 msec respectively. The "on" resistance is in the range of 2.1 /spl sim/35.6 ohms. The "off" resistance is greater than 10/sup 12/ ohms. The breakdown voltage between the open electrodes is above 400 V. Keeping the NO bimorph segment of the bistable relay activated, a normally closed microrelay is also demonstrated.