Nanomechanical Disk Resonator-on-Membrane with Pico-Meter Deflection Resolution

This paper reports on fabrication of nano mechanical disk resonators on micro-thick membranes and characterization of their resonance frequency shift due to air-pressure induced membrane deflection. Finite element analysis (FEM) has been used to show the estimate deflection at the center of the membrane. For the $20\mu \mathbf{m}$ thick, 2mm diameter membrane in this work, 1mPa of pressure change corresponds to 2pm of deflection (shear stress of 12Pa at the center of the membrane). Measurements show highest resonator sensitivity of 0.5Hz per pico-meter of deflection at the membrane center. In addition, it is shown that as the dimension of disks decreases from $20\mu \mathbf{m}$ to $5\mu \mathbf{m}$, the resonator sensitivity increases by about 8 times.