Piezoresistive Slot-Cantilever Type Accelerometer Inspired from Spider's Slit Sensilla

摘要

This paper presents a new method by introducing rectangular slits into cantilever to improve the sensing performance of piezoresistive cantilever-type accelerometer. The designed accelerometer consists of a heavy proof mass and supported by a thin slot-cantilever. The slits are inspired from spider's slit sensilla and can be used to amplify the stress/strain due to stress concentration, thus increasing the sensitivity without decreasing too much bandwidth. For the designed accelerometer, an analytical model is established to analyze the sensing performance, and its specifications such as output voltage, sensitivity, resonant frequency are theoretically calculated. The results demonstrate that the sensing performance are greatly affected by the structural dimensions, especially the slits and cantilever. Compared with the simple accelerometer without slits, the sensing performance can be greatly improved by introducing slits. Then, the proposed accelerometers are fabricated by using bulk silicon micromachining technology. Series of testing experiments are conducted to study the sensing performance. Both analytical and experiment results show that high sensitivity and large resonant frequency can be simultaneously realized by introducing slot-cantilever structure.