An inertial-grade laterally-driven MEMS differential resonant accelerometer

Inertial-grade laterally-driven differential resonant accelerometer (DRXL), using a gap sensitive electrostatic stiffness change effect, is designed, fabricated and tested using a mixed micromachining process based on (111) single crystal silicon. The resonant accelerometer consists of a double ended tuning fork (DETF) and two proof masses in the same plane, so it can detect in-plane acceleration. Each pair, with proof mass and resonator, is completely isolated, so the coupling of mechanical vibration between them is protected. The fabricated accelerometer shows a sensitivity of 64 Hz/g per resonator at nominal frequency of 24,888 Hz, bandwidth of 110 Hz, and a bias stability of 5.2 μg.