基于MEMS技术的集成压力-湿度传感器OACSTPCD

In this paper,a high-sensitivity integrated humidity and pressure sensor chip is designed.The pressure sensing unit is based on the silicon on insulator(SOI)and serpentine resistors structure.The sensitivity of the sensor at room temperature is 0.026 mV/kPa with the pressure of 3 kPa to 129 kPa,which is consistent with the finite element simulation.The thermal sensitivity shift reaches 0.004‰FS/℃and the thermal zero shift is 0.25% FS/℃.The humidity sensing unit adopts interdigital electrodes(IDT)and capacitive structure.The hydrophobic group introduced by fluorinated polyimide(PI)is used as the humidity sensitive film.The design of Mo resistance heating structure speeds up the dehumidification process of the sensor and shortens the dehumidification time by nearly 32%.In the humidity range of 10% RH to 90% RH,the sensitivity of the humidity sensor with fluorinated PI reaches 0.121 pF/% RH,slightly lower than the fluorine-free sensor.The humidity hysteresis of the sensor with fluorinated PI is reduced by 16% compared with the sensor without fluorinated PI.The capacitance-humidity curve is an exponential distribution,the correlation coefficient R2=0.996.The test results show that the humidity sensing unit and the pressure sensing unit have good independent performance.