硅纳米悬臂梁传感结构压阻特性的试验研究

摘要

为了研究拉伸和大形变弯曲共存状态下硅纳米悬臂梁传感结构的压阻特性,采用CMOS工艺制作了硅纳米悬臂梁传感测试结构,结合原子力显微镜和半导体参数测试仪对其电学参数进行了测量,其位移灵敏度高达1.582 16 ×10-4m.在电阻相对变化率实验测量和ANSYS有限元平均应力仿真的基础之上,进而提出了一个非线性压阻模型来提取大弯曲硅纳米悬臂梁的一阶和二阶压阻系数.研究结果表明:其一阶压阻系数约为体硅的5倍,该巨压阻效应为利用硅纳米压阻传感结构来实现超高灵敏度的纳米压力传感器提供了可能的途径.研究结果同时也揭示了要获得高的灵敏度和好的可靠性,硅纳米悬臂梁的长度设计需要折衷考虑.%In order to study the piezoresistive characteristics of silicon nanocantilever sensing structure under the coexistence state of stretching and deformation bending, CMOS process is used to manufacture silicon nanocantilever sensing structure, and atomic force microscope and semiconductor parameter tester are used to measure the electrical parameters of silicon nanocantilever,and the measured displacement sensitivity is 1.582 16 × 10 -4m. On the basis of experimental measurements of the relative change rate of resistance and the ANSYS finite element simulation of average stress, a nonlinear piezoresistive model is proposed to extract the first-order and second-order piezoresistive coefficients of the bent silicon nanocantilever. Research results show that the first-order piezoresistive coefficient is approximately 5 times that of the bulk silicon, and the significantly enhanced piezoresistive effect provides possible ways for the use of the silicon nano piezoresistive sensing structure to achieve ultra-high sensitivity design of the pressure nanosensor. Furthermore, the results also reveal that the length design of the silicon nano-cantiLever needs trade-offs in order to obtain high sensitivity and good reliability.