Sub-1-volt Piezoelectric Nanoelectromechanical Relays With Millivolt Switching Capability

The design, fabrication, and characterization of the first piezoelectric nanoelectromechanical relays with sub-1-volt actuation (520 mV) are presented. The low actuation voltage is enabled by employing ultrathin piezoelectric aluminum nitride films (10 nm) with high c-axis orientation and controlled residual stress in a stress-compensating geometry. Two different actuation methods based on optimized four-layer unimorph actuators are used to synthesize normally closed relays with high mechanical restoring forces. The first experimental demonstration of few millivolts switching (10 mV) using the realized relays is also presented. The relays exhibit a very low energy dissipation per switching cycle (23 aJ), an extremely small subthreshold slope (0.013 mV/decade), and a low ON-state resistance (2.3 kQ).