A Small and High Sensitivity Resonant Accelerometer

Abstract

This abstract presents the design, the fabrication and the measurements of a very small and sensitive resonantaccelerometer. The sensor is based on a strain sensitive vibrating beam attached to a mass. The vibration of thebeam is electrostatically driven and the detection of the signal is capacitive.The sensor is fabricated thanks to potential ”In-IC” compatible thin SOI-based technologies, allowing the patterningof submicron gaps. The beam dimensions are at the micron scale while the gap used in the capacitive detection is inthe nanometer range (750 nm).The sensitivity of the accelerometer is measured with a phase lock loop (PLL) built using a lock-in amplifier (LIA)controlled with a computer program. The measured sensitivity is 22 Hz/g and the maximum resolution is smallerthan 5 mg (5Hz integration bandwidth).The results presented in this paper show that the miniaturization of resonant accelerometers can lead to a goodsensitivity and resolution.