A Monolithic Multi-sensor for three-axis Acccelerometer, Absolute pressure and Temperature

A monolithic multi-sensor for use in the severe environments is presented in the paper. This monolithic multi-sensor is realized by using (100) SOI wafer, which consists of a three-axis piezoresistive accelerometer, a piezoresistive absolute pressure sensor and a silicon thermistor temperature sensor. The three-axis accelerometer has been designed with four silicon beams to support the mass. The appropriate piezoresistor arrangement in four beams can detect three-axis acceleration and eliminate cross-axis sensitivities. The pressure sensor consists of silicon membrane with four piezoresistors and vacuum chamber between silicon membrane and pyrex glass substrate. In order to minimize the effect of stress on temperature sensor, the thermistor made of boron ion-implanted is along [100] and [010] crystal orientation. The multi-sensor chip is fabricated by using bulk-micromachining technology and silicon-on-glass anodic bonding technology. The die size of the chip is 4times6times0.9 mm³. Measure results show the performance of the multi-sensor.