Method for sensitivity improvement and optimal design of a piezoresistive pressure sensor

This study reports a systematic approach to achieve optimal design of a piezoresistive sensor under the limitation of fabrication capabilities. The commercial finite element analysis (FEA) software, CoventorWare, is employed to evaluate the candidate designs of a piezoresistive pressure sensor. The Taguchi´s robust design method is further employed to consider the deviation from manufacturing (e.g. dimensions, alignment, etc.). The full scale span (sensitivity) of the sensors was chosen as quality characteristics. The effects of manufacturing related restrictions were estimated by the noise factor analysis. Then, the optimal design of a sensor, which realizes the optimization of sensor signal output and minimization the influence of the variation of the design factors, is achieved through thoughtful considerations and arrangements. In application, the micro pressure sensor is design and fabricated, and the full scale span of sensor has been improved for 20% (from 78.3mV to 94mV).