A piezoresistive accelerometer with axially stressed tiny beams for both much increased sensitivity and much broadened frequency bandwidth

A single-wafer-based piezoresistive accelerometer, consisting of two axially stressed tiny beams and a central bending cantilever, has been proposed for both much improved sensitivity and bandwidth compared with conventional piezoresistive accelerometers. Analytical modeling has been studied for optimized design and scaling rules of the sensors. Finite element method (FEM) simulation results agree well with the analyses. The accelerometers are fabricated in silicon-on-insulator (SOI) wafer by using bulk micromachining techniques including deep-reactive-ionic-etch (DRIE). The formed devices are characterized with typical sensitivity as 106 mv/5v/g and 1/sup st/ mode resonant frequency as 1115 Hz, 10.6 and 2.23 times equivalent to the specifications of a typical conventional cantilever-mass piezoresistive accelerometer.