Single crystal silicon is widely used in the MEMS devices.Based on the principle of the equivalent stiffness,single crystal silicon is simplified as an isotropic material.The equivalent Young's modulus and the Poisson's ratio of the slanted silicon beam which is fabricated by means of anisotropic wet etching are measured using a frequency response test.A total of eight groups of slanted beam are fabricated on the(100) silicon wafer.The widths of the beams range from 30 μm to 240 μm at an interval of 30μm,while the ratios of the width to the thickness range from 1/8 ～ 1 at an interval of 1/8 respectively.It is proved that there is no correlation between the equivalent Young's modulus and the dimensions of the anisotropic slanted beam.However,the equivalent Poisson's ratio does not only relate to the characteristics of the crystal silicon,but also relate to the dimensions of the slanted beam.Based on the experimental study,the equivalent Young's modulus is 170.51 GPa±2.08 GPa.The equivalent Poisson's ratio is fitted with polynomials in Matlab,and the polynomial of degree 7 coincides with the measured data exactly.%单晶硅广泛应用于MEMS器件中.根据等效刚度原理,单晶硅可以简化为各向同性材料.介绍了一种采用湿法腐蚀工艺加工的倾斜硅梁,并利用频率响应特性测试了其等效杨氏模量和等效泊松比.采用(100)硅片制作了八组不同尺寸参数的倾斜硅梁.梁的宽度尺寸间隔为30 μm,尺寸范围为30 μm～ 240 μm,对应宽高比为1/8～1.实验结果证明了等效杨氏模量与倾斜梁尺寸无关,而等效泊松比不仅和单晶硅的特性相关,而且受倾斜梁尺寸的影响.实验得到的等效杨氏模量为170.51 GPa±2.08 GPa.对等效泊松比的测量结果在Matlab中进行了多项式拟合,7次拟合多项式已经与测试结果具有很好的一致性.
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