原子力显微镜探针耦合变形下的微观扫描力研究

原子力显微镜(AFM)的微探针系统是典型的微机械构件，它在接触扫描过程处于耦合变形状态.采用数值模拟方法探究恒力模式下探针耦合变形对微观扫描力信号、微观形貌信号的影响.研究表明，AFM的恒力模式扫描中，法向扫描力并不是恒定大小，与轴向扫描力存在耦合作用，在粗糙峰峰值增加阶段，二力均增加；在粗糙峰峰值减小阶段，二力均减小；该耦合作用随形貌坡度、针尖长度等增加而加强.微观形貌的测试信号和横向扫描侧向力信号受探针耦合变形影响较小，但侧向力与形貌斜率密切相关，且其极值点与形貌极值点存在位置偏差，这些结果均与原子力 关键词： 原子力显微镜 探针悬臂梁 耦合变形 扫描力

On micro scanning forces under the coupling deformation of atomic force microscope probe

Micro cantilever probe of atomic force microscope (AFM) is a typical micro mechanical component, which is under a coupling deformation during the contact scanning process. Numerical simulations of micro scanning forces and micro topography are presented to investigate the influence of the coupling deformation of AFM probe under the AFM contact mode. It is demonstrated that the normal scan force is actually not constant, which is coupled with the lateral force on an asperity of sample surface, increasing together uphill and decreasing together downhill. The coupling relationship increases with the surface slope, tip height, etc. Coupling deformation of the probe proves to play a minor role on the AFM micro topography image and the perpendicular scan force. However, surface slope plays an important role on the variation of lateral force, and the peak positions of lateral force are not accordant with that of surface topography. These results are in good agreement with those previous AFM experiments.