Sub-100 mV Computing With Electro-Mechanical Relays

The energy efficiency of a CMOS digital logic circuit is fundamentally limited by the nonideal switching behavior of transistors, specifically their nonzero off-state current and finite subthreshold slope. In contrast, mechanical switches (relays) can achieve zero off-state current and perfectly abrupt switching characteristics; therefore, they have attracted growing interest for ultralow-power computing applications. A challenge for electro-mechanical relay technology is to reduce the hysteresis voltage, because this sets the minimum operating voltage of the relays. Herein, we report a surface-micromachinedelectrostatically actuated relaywith <;70-mV hysteresis voltage, achieved by designing it to have relatively large structural stiffness and to operate in nonpull-inmode. A relay-based inverter circuit is demonstrated to operate reliably with a switching voltage below 100 mV, representing a significant milestone toward ultralow-power mechanical computing.