High-performance capacitive microaccelerometer using large proof-mass and high-amplitude sense voltage

We present a high-performance surface micromachined capacitive accelerometer, in which the mechanical noise was reduced by a large proof-mass (83.12 μg) and the electrical noise was decreased by a high-amplitude sense voltage (up to 12 Vpp). The proof-mass was increased by using a fabrication process involving anodic bonding of silicon and glass wafers, and by using a non-porous structure of the proof mass. In addition, by using a metal layer patterned on the glass substrate, the notch effect caused by deep RIE process was eliminated. Thereby the weight of the proof-mass could be further increased. The nonlinearity problem, caused by the high-amplitude sense voltage, was avoided using breached finger sensing electrodes. Experimental results showed that the total noise floor and the nonlinearity of the present microaccelerometer are 21.87 μG√Jm and 0.01534%, respectively.