U形阵列式微机械悬臂梁的研究

A study of U-shaped micromachined cantilever array

为提高悬臂梁的分辨率 ,实现悬臂梁的多功能性 ,设计了一种U形阵列式压阻悬臂梁 .从理论上对悬臂梁的应力、噪声和灵敏度进行分析 ,优化了悬臂梁及力敏电阻的几何尺寸 .选用多晶硅为力敏材料 ,基于硅微机械加工技术 ,制备U形阵列式悬臂梁 .测量悬臂梁的噪声及灵敏度 ,得到多晶硅力敏材料的Hooge因子和应变灵敏度系数 ,分别为 3× 10 - 3和 2 7.在 6V偏压和 10 0 0Hz测量带宽条件下 ,计算悬臂梁的最小可探测位移为 0 5nm .同时对多晶硅力敏电阻噪声的产生机理进行了探讨 .

In order to increase the resolution and realize the versatility of cantilever, U-shaped piezoresistive cantilever array has been designed and fabricated in this research. The optimized geometries of cantilever and piezoresistor were determined by analyzing the stress, noise and sensitivity of piezoresistive cantilever from theory. Based on silicon micromachining technology, the piezoresistive cantilevers were fabricated by using polysilicon as the piezoresistive materials. With the measurement results of noise and sensitivity, the Hooge factor was calculated to be 3×10 -3 , the gauge factor is 27, and the minimum detectable deflection of piezoresistive cantilever was calculated to be 0 5nm at a 6V bias voltage and a 1000Hz measurement bandwidth. The noise sources of polysilicon pizeoresistor are also discussed in this paper.