Enhancing Sensing in Nanoscale: Investigation of Smart Nanomechanical Cantilever Array

Abstract: In this report, a novel smart nanocantilever with self-deflection sensor using embedded piezo-resistor and self-actuation using integrated piezo-electric actuator is proposed, designed and simulated to enable highly sensitive label free biosensor and ultra-short cantilever probe for AFM applications. The smart nanocantilever comprises of a triangular Si3N4 nanocantilever (10µm long, 400nm width and 100nm thickness) connected to a multi-layer support structure (Si3N4 (100nm)/PZT (100nm)) having n-type silicon piezo resistor (7µm long ,2µm width and 20nm thickness) embedded in the Si3N4 layer in both the support structure and nanocantilever. The nanocantilever is designed to maximize the resonance frequency and lower spring constant whereas piezoelectric actuator and piezo resistor is designed to maximize excitation and maximize change in resistance of nanocantilever respectively. The results show that the nanocantilever enhances sensitivity in static mode by factor of 36.5 while in dynamic mode by a factor of 658 for AFM application. For biosensor application, the nanocantilever enhanced the sensitivity in static and dynamic mode by factors of 5.6 and 13.8, respectively.