INTERNAL ELECTROSTATIC TRANSDUCTION STRUCTURES FOR BULK-MODE MICROMECHANICAL RESONATORS

摘要

An electrostatic transducer for micromechanical resonators, in which the electrode gaps are filled with a dielectric material having a much higher permittivity than air. This internal electrostatic transducer has several advantages over both air-gap electrostatic and piezoelectric transduction; including lower motional impedance, compatibility with advanced scaled CMOS device technology, and extended dynamic range. In one aspect, in order to minimize energy losses, the dielectric material has an acoustic velocity which is matched to that of the resonator material. Internal electrostatic transduction can be adapted to excite and detect either vertical modes (perpendicular to the substrate) or lateral modes (in the plane of the substrate). Its increased transduction efficiency is of particular importance for reducing the motional resistance of the latter.