High temperature dynamic pressure sensor and experimental analysis

The inverted cup-type high-temperature piezoresistive pressure sensitive chip with the range of 25MPa was developed by the Micro Electro-Mechanical Systems (MEMS) and Silicon on Insulator (SOI) technology. The sensitive piezoresistors are isolated from the silicon substrate by the silicon dioxide, and thus the stability and reliability problems of the pressure sensitive chip are solved at high temperatures beyond 120℃. The flush-type mechanical packaging structure was designed to avoid the channeling effect and improve the dynamic response frequency of the sensor. For the fabricated high temperature dynamic pressure sensor, the static and dynamic performance experiments were carried out to obtain the sensor's fundamental performance and analyze its uncertainty at the static experimental temperature of 250℃. The results show that the sensor accuracy is ±0.114%FS and the uncertainty is 0.017 94mV. The thermal zero drift and thermal sensitivity drift were calculated. The dynamic response frequency was calculated as 555.6 kHz through dynamic performance experiment. Therefore, the developed MEMS pressure sensor has fine accuracy and high natural frequency at high temperatures.