Abstract: A novel capacitive pressure sensor is presented,whose sensing structure is a solid-state capacitor consisting of three square membranes with Al/SiO2/n-type silicon.It was fabricated using pn junction self-stop etching combined with adhesive bonding,and only three masks were used during the process.Sensors with side lengths of 1000,1200,and 1400μm were fabricated,showing sensitivity of 1.8,2.3,and 3.6fF/hPa over the range of 410~1010hPa,respectively.The sensitivity of the sensor with a side length of 1500μm is 4.6fF/hPa,the nonlinearity is 6.4%,and the max hysteresis is 3.6%.The results show that permittivity change plays an important part in the capacitance change.

Key words: capacitive pressure senor, electrostriction, pn junction self-stop etching, adhesive bonding, linearity