50 nm thick AlN resonant micro-cantilever for gas sensing application

Abstract

We present the fabrication and characterization of a 90µm × 40µm × 885nm piezoelectric micro-cantilever resonator containing a 50nm thick Aluminum Nitride (AlN) piezoelectric film for transduction. Material characterizations demonstrate that our AlN deposition technique enables the fabrication of ultra-thin films with high piezoelectric coefficient e31 = 0.78C.m⁻². Fully electrical actuation and detection of the cantilever resonance behavior is evidenced using onchip electric bridge and instrumented probe trans-impedance amplifier. Finally, based on Allan deviation measurement results, we demonstrate the potential of this cantilever for gas detection with an expected limit of detection equal to 70zg.µm⁻²