Design optimization of a high performance silicon MEMS piezoresistive pressure sensor for biomedical applications

In this paper the design optimization of high performance conventional silicon-based pressure sensors on flat diaphragms for low-pressure biomedical applications has been achieved by optimizing the doping concentration and the geometry of the piezoresistors. A new figure of merit called the performance factor (PF) is defined as the ratio of the product of sensor sensitivity (S) and sensor signal-to-noise ratio (SNR) to the temperature coefficient of piezoresistance (TCPR). PF has been introduced as a quantitative index of the overall performance of the pressure sensor for low-range biomedical applications. A comprehensive analysis considering the impact of doping concentration, length of the piezoresistor and thickness of the diaphragm indicates that for achieving the highest figure of merit an optimum concentration of 1018 atoms cc−1 and geometry of 100 µm long piezoresistor and 10 µm thick membrane for the specified biomedical application are required.