J2210303 Quality factor enhancement of Si resonators by nonlinear damping

The Q factor enhancement of Si resonators using nonlinear damping is investigated for highly sensitive resonant sensors. The thermomechanical noise, which limits the physical resolution of resonant sensors, can be improved by increasing the Q factor. In this paper, the nonlinear damping effect of thin Si resonators was investigated and the Q factor enhancement caused by nonlinear damping is measured. The resonator thickness used for the Q factor measurements are 100, 400, 800, 1500 nm. The Q factor of the 100 nm-thick resonator is dramatically increased as its vibration amplitude become larger, while the Q factor change become smaller as the resonator thickness become thicker. These results show that Si resonators have the nonlinear damping effect, and the large Q factor enhancement by this effect is markedly observed in the thin resonator. It is concluded that the Q factors of nanomechanical resonators can be increased by only adjusting its vibration amplitudes.