基于AIN绝缘的多晶硅高温压力传感器设计

Design Of High-Temperature Pressure Sensor Based On AlN And Polysilicon Membrane

探讨了一种多晶硅高温压力传感器的设计方法,采用AlN作硅衬底和多晶硅力敏电阻条之间的电绝缘层,由于无p-n结,力敏电阻无反向漏电,使制作的压力传感器特性好。利用多晶硅材料在高温条件下能够表现出良好的压阻特性,考虑其纵横向压阻效应的不同,作了理论分析,在此基础上制作力敏电阻条。利用有限元分析方法,借助MARC软件,模拟了传感器承压弹性膜的应力场分布,确定了多晶硅力敏电阻条的位置和排列方式。并且施加10kPa压力时,模拟了不同膜厚t与对应的最大应力σ11的曲线;模拟了11方向主应力COMP11边缘中点应力为一特定值时所需压力PN与膜厚t的关系曲线。

A design method of polysilieon high-temperature pressure sensors was demonstrated. The sensing resistors were fabricated on the chip, dielectrically insulated by AIN, so there was no reverse leakage current through p-n junctions at high temperatures. The properties of the pressure sensor insulated by AIN film arc particularly excellent. Using the model of polysilicon and experimental results about the difference between vertically and horizontally effect, a theoretical analysis for piezoresistive characteristics of polysilicon in high temperatures is made. Under the guide of Finite-Element Analysis （FEA） theory, the stress distribution on silicon membrane is simulated by using MARC software. The optimum position and arrangement of four piezoresistors on the square film were determined. A curve of the maximum stress σ11 versus film thickness t have been obtained when 10kPa pressure being applied on membrane. The curve of the pressure PN ,needing for the given value of stress at the midpoint along edge, versus film thickness t was also plotted by simulation.