Shear dependent nonlinear vibration in a high quality factor single crystal silicon micromechanical resonator

The frequency response of a single crystal silicon resonator under nonlinear vibration is investigated and related to the shear property of the material. The shear stress-strain relation of bulk silicon is studied using a first-principles approach. By incorporating the calculated shear property into a device-level model, our simulation closely predicts the frequency response of the device obtained by experiments and further captures the nonlinear features. These results indicate that the observed nonlinearity stems from the material's mechanical property. Given the high quality factor (Q) of the device reported here (∼2 × 10 ⁶), this makes it highly susceptible to such mechanical nonlinear effects.