Self-Powered Timekeeping and Synchronization Using Fowler–Nordheim Tunneling-Based Floating-Gate Integrators

Abstract

Self-powered timers provide a mechanism to achieve temporal synchronization between two passive devices (for e.g., RF tags, credit/access cards, and thumb drives) without the need for any external powering or clocks. As a result, the timers could be used to implement dynamic SecureID type authentication involving random keys and tokens that need to be periodically generated and synchronized. We report a novel solid-state self-powered timer, which exploits a self-compensating mechanism in the physics of Fowler–Nordheim quantum transport of electrons tunneling onto a floating gate. The proposed devices have been fabricated using standard CMOS processing and are demonstrated to be operational for durations greater than three years using extrapolation studies. The fabricated devices were also found to be extremely robust to device mismatch and as a result of which, the proposed self-powered timers can be synchronized with respect to each other with an accuracy greater than 0.5%.