关键词: 压力传感器, 全介质隔离, SOI, CMOS工艺

Abstract: Aiming at requirements of 25 MPa pressure measurement in the high-temperature environment of the nuclear industry, a high-temperature MEMS pressure sensor chip based on CMOS process is designed and implemented. The chip is fabricated using silicon-on-insulator (SOI) wafer, achieving full dielectric isolation through silicon trench and filling processes, which effectively avoids the issue of intrinsic excitation leakage in PN junction isolation under high temperatures and enhances thermal stability. Experimental results show that the chip pressure measurement range is 0-25 MPa. At room temperature, its nonlinear error is better than 0.35%FS, the sensitivity reaches 3.95 mV/MPa, the piezoresistor linear error is less than 0.07%, with a temperature coefficient of 2001.17×10^-6/℃ at 275 ℃, the zero temperature drift of the sensor is within -0.08 mV/℃, and the thermal stability time is shortened by 34.29% compared with that of traditional trench isolation. This design is anticipated to offer a reliable solution for pressure measurement in high-temperature nuclear environments and promote the development of CMOS MEMS integration technology.

Key words: pressure sensor, full dielectric isolation, silicon-on-insulator, CMOS process