A bossed diaphragm piezoresistive pressure sensor with a peninsula-island structure for the ultra-low-pressure range with high sensitivity

A sensor chip with a bossed diaphragm combined with a peninsula-island structure was developed for a piezoresistive pressure sensor. By introducing a stiffness mutation above the gap position between the peninsula and island structures, the strain energy of the proposed diaphragm was mainly concentrated upon the gap position, which remarkably increased the sensitivity of the sensor chip. A beam-diaphragm coupled model and an optimization method for the novel sensor chip were also developed, which gave guidelines for optimizing the sensor chip structure. Finally, a sensor chip with the bossed diaphragm combined with peninsula-island structure was fabricated and tested. The experimental results showed that the proposed sensor chip was able to measure ultra-low pressure within 500 Pa with high sensitivity.