文中设计了一种浅凸台结构的SOI压阻式压力传感器。这种膜片结构解决了由于压力量程扩展导致传感器的灵敏度和线性度无法同时满足使用要求的问题。考虑电阻的设计约束以及浅凸台制作过程中的光刻和刻蚀偏差,采用U型电阻保持高灵敏度和线性度。利用ANSYS软件模拟了膜片结构的力学性能,验证了理论分析的正确性;仿真优化了电阻的形状和位置,预估了传感器的性能。介绍了敏感单元的加工工艺。设计的传感器灵敏度为93.4μV/(V·k Pa),非线性误差小于0.22%,可实现对量程高达10 MPa压力的测量。
A piezoresistive SOI pressure sensor with a shallow-boss configuration was designed. This sensor solved the contradiction between sensitivity and linearity for measurement range extension. U-shaped piezoresistors were adopted by taking design restraints,photolithography and etching deviation for shallow-boss structure fabrication into account. In order to verify the theoretical analysis,ANSYS software was conducted to simulate the mechanical properties of diaphragm structure. Simulation results also were used to optimize location and geometry of piezoresistors and evaluate the performance of the sensor. Process flow was presented. The sensitivity of the device is 93. 4 μV /( V·k Pa) and the nonlinearity error is less than 0. 22%. The device can realize pressure measurement within the range of 10 MPa.