In measuring topography of sample, the interaction between tip and sample will cause the deformation on the sample surface and the deformations will be different in the regions with different mechanical property. Furthermore, the deformations will cause non-negligible error in topography measurement. Theory analyses are carried out on this measurement error and further numerical research shows that mixed signals with high-frequency components are able to eliminate the measurement error. However, it is difficult to measure high-frequency signal for normal cantilever. In order to gain a proper high-frequency signal, a modified cantilever is introduced. The new designed cantilever can help us to adjust the relative values of eigen-frequencies of a cantilever and then enhance the high-frequency signal.%采用原子力显微镜测量样品表面形貌时,针尖与样品间的相互作用力会使样品表面不同力学性质的区域变形量不同,从而使得形貌测量结果产生偏差.首先研究了引起形貌测量偏差的机理,进一步通过数值计算发现通过引入高频信号与低频信号叠加作为新的形貌测量信号可以近似避免这一类形貌测量偏差.但是对于普通的矩形截面悬臂梁提取高阶信号是比较困难的,通过外加弹簧的结构设计来调节悬臂梁各阶本征频率相对值,使得在实验测量过程中可以较方便地提取悬臂梁振动的高频信号.
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