Electrostatically driven micro resonator with a CMOS capacitive read out

An electrostatically driven micro resonator is fabricated from single-crystal silicon, using micromachining techniques. The displacement amplitude is measured through differential capacitance measurement, implemented on a CMOS interface circuit, which also provides the excitation clocks for the resonator. The unique feature of this micromechanical system is the integration method applied for attaching the resonator to the CMOS chip. The integration is based upon indium bumps technology, which is now established in modules of infra-red focal plane arrays. A technology which is extended here for the first time, to the best of our knowledge, to microelectromechanical systems.