Rotational Mode Disk Resonators for High-Q Operation in Liquid

This work presents thermally actuated rotational mode micromechanical disk resonators with piezoresistive readout specially designed for high-Q operation in liquid. Unlike the previously demonstrated micro-resonators operating in liquid, all the surfaces of the proposed structures in the resonant mode of interest slide in parallel to the liquid interface having minimal interaction with the surrounding fluid. This has been shown to significantly reduce the energy loss into the liquid as well as mass loading by the liquid. Quality factors as high as 280 have been measured for such resonators operating in water which is more than three times higher than the highest values previously reported. Much higher quality factors are expected to be achievable by further optimization of resonator dimensions and other design parameters.