CMOS micromachined capacitive cantilevers for EFM-based mass data storage

This work presents the CMOS capacitive cantilevers intended for detecting charge-induced electrostatic force in an EFM-based data storage device. The cantilever can be electrostatically actuated and perform capacitive sensing of the resonant amplitude. Force detection in the nN range can be achieved through the sharp tips placed in close proximity with respect to the storage medium when reading a bit. The static characterization shows a measured capacitive sensitivity of 2.4times10⁵ V/m at a gap of 1.6 mum, equivalent to an input-referred noise force of 0.054 nN/Hz^1/2. The dynamic measurement shows the resonant frequency shift due to the increased electrostatic force averages 56 Hz/nN.