Ultra-Low Voltage MEMS Resonator Based on RSG-MOSFET

Abstract

16MHz and 91MHz micromechanical resonators based on the Resonant Suspended-gate MOSFET (RSG-MOSFET) architecture are demonstrated. A fabrication process using a polysilicon sacrificial layer and an aluminum-silicon alloy (AlSi 1%) suspended-gate was developed. Static and dynamic electrical characteristics of the Clamped-Clamped beam (CC-beam) resonator have been investigated in order to explain the device behavior. The lowest reported actuation voltage for a MEMS resonator, less than 1V, makes the resonator compatible with standard CMOS voltages. The actuation voltage dependence on the MOSFET characteristics and the threshold voltage is explained. A resonant frequency tuning of 750kHz was achieved by a 240mV DC voltage variation, and a quality factor of Q= 641 was calculated from measurements in vacuum.