Volatile or non-volatile switching? Establishing design parameters for metal-contact relays using ON/OFF hysteretic behavior (RT to 300 °c)

Abstract

This Letter presents a systematic evaluation of the adhesion force between sub-micrometer metal (molybdenum) surfaces in microelectromechanical (MEMS) relays for a range of temperatures (RT to 300 °C). As adhesion force controls whether an electrostatic actuated MEMS relay will detach or remain in contact once the power is turned-off, therefore, it is essential to know the amount of adhesion force present between the interacting electrodes. We present a theoretical scheme that allows direct extraction of the adhesion force from experimentally measured data (ON/OFF-voltage) that can precisely determine the adhesion force from the micro- to nanoregime. Our model identified a clear correlation between the two properties, i.e., ON/OFF-voltage and adhesion force and applicable for any arbitrary material systems. The model is validated by experimental results with varying design parameters. The results confirm that the decreasing nature of pull-OFF voltage (13.9 V to 10.8 V) with increasing temperature ensures a large hysteresis window (∼4.7 V at 300 °C) for n = 3 × 6 and W / L - 1 ∼6.67, where n is the contact-area dimension and W / L - 1 is related to movable electrode geometry. The proposed method can be adopted for the precise designing of various logic relays or memory elements suitable for a wide temperature range.