A high sensitive pressure sensor with the novel bossed diaphragm combined with peninsula-island structure

•A bossed diaphragm combined with peninsula-island structure was presented for ultra-high sensitive pressure sensor.•Compared with other pressure sensor with different diaphragm structure, the proposed diaphragm featured bossed diaphragm combined with peninsula-island structure has the highest sensitivity and first resonance frequency with relatively low non-linearity error.•A designing method and the optimization process of the bossed diaphragm combined with peninsula-island structure was presented to give a designing guidance for the proposed diaphragm.•A pressure sensor has been fabricated and experiment has been carried out to verify the proposed diaphragm. A Micro Electromechanical Systems (MEMS) piezoresistive pressure sensor chip with high sensitivity has been developed to measure the ultra-low pressure of several mbar. A novel bossed diaphragm combined with peninsula-island structure is designed. The proposed diaphragm can alleviate the trade-off between sensitivity and non-linearity to realize the measurement of ultra-low pressure with low non-linearity. Especially, the strain energy dissipating outside the stress concentration region (SCR) is reduced remarkably by the proposed diaphragm to achieve high sensitivity. The optimization process for the proposed diaphragm has been presented by finite element method (FEM) to make the sensor chip achieve a higher sensitivity and a lower non-linearity. A fabricated pressure sensor was packaged with the proposed sensor chip and tested to obtain the sensitivity of 0.066mV/V/Pa and non-linearity of 0.33%FS in the working range of 0–500Pa. The proposed sensor chip is potentially a better choice for high sensitive pressure sensor.