A High-Performance Monolithic Triaxial High-G Accelerometer

A high-performance monolithic triaxial piezoresistive accelerometer is developed for 50000-100000g measure range. An axial-stressed tiny-beam scheme is developed for the X and Y axial elements and a three-beam twin-mass structure is developed for Z-axis element. Both of these structures feature high sensitivity and high resonant frequency. The three sensing elements are monolithically integrated by micromachining techniques of double-sided deep etching combined with piezoresistive processes. A dropping-hammer calibration system is used to characterize the accelerometer. The sensitivity of the three elements is measured as 2.17, 2.25 and 2.64muV/g/5V respectively and the resonant frequency is 308, 303 and 164 kHz for each axial element. A novel time-domain separation method using a long and thin aluminum alloy bar is developed for the dropping test of cross-axis sensitivity. With this measurement technique, satisfactory cross-axis sensitivity is experimentally obtained for all the three axial elements, which contributes to the high-performance monolithic triaxial shock accelerometer.