Electromechanical Behavior of Interdigitated SiO₂ Cantilever Arrays

Bending and first flexural mode vibration behavior of electrostatic actuated nanometer-sized interdigitated cantilever arrays are characterized under vacuum conditions. The ``pull-in'' effect in dc driving and the ``hard spring effect'' in ac driving are observed. A mass sensitivity of 20 fg is expected for our devices due to the ultra-small mass of the arm and relative high Q factor. The mass-spring lump model combined with Green's function method is used to fit the dc driving behaviors including the pull-in voltage. For the ac driving case, the polynomial expansion of the capacitive force is used in the model. The successfully fittings of the pull-in voltage and the hard spring effect prove that our simulation method could be used for guiding the geometrical design of cantilever-based sensors.