Characterization and analysis of a novel structural SOI piezoresistive pressure sensor with high sensitivity and linearity

A novel structural piezoresistive pressure sensor with four-grooved diaphragm combined with rood beam has been proposed for low pressure measurements of less than 1 psi. The proposed sensor chip is fabricated on a SOI wafer by traditional MEMS micromachining and anodic bonding technology. By localizing more strain energy in the stress concentration region and increasing the constraint of the partial pedestal, the sensor achieved a high sensitivity and linearity of 30.9 mV/V/psi and 0.25% FSS respectively at room temperature, and thereby the contradiction between sensitivity and linearity is alleviated. Besides, a sensitivity of 21.2 mV/V/psi and a linearity of 0.5% FSS were obtained at 150 degrees C, which illustrates that the proposed sensor has a stable high temperature output characteristic. Additionally, the mechanisms about strain energy transmission and partially stiffened diaphragm are also discussed.