SPM抑振系数的理论与实验研究

Theoretical and Experimental Study on Vibration Rejection Ratio of SPM

为分析外界振动对扫描探针显微镜(SPM)针尖-样品副的影响,提出“抑振系数”的概念.围绕SPM针尖-样品副的动态力学模型,对抑振系数的物理含义、影响因素等进行了理论分析.搭建了SPM激振、测振的实验系统,对不同的SPM扫描器、探针、样品、针尖预应力以及针尖-样品副开/闭环对SPM抑振系数的影响进行了实验研究.在理论分析上和实验研究中,都证实SPM抑振系数与悬臂梁的有效质量、弹性系数、空气阻尼系数、针尖与样品的接触弹性系数和接触阻尼系数等相关,反映在实际SPM部件参数上,则较短的扫描器、较长的悬臂探针、较软的样品表面、较大的探针预应力、闭环控制的针尖-样品副等都是提高SPM抑振性的途经.

To analyze the influence of external vibration on the tip-sample interaction of scanning probe microscope（SPM）, a concept, vibration rejection ratio（VRR）, was proposed. Concentrating on the dynamic mechanics model of SPM tip-sample interaction, the physical meaning and influence factors of VRR were analyzed theoretically. A vibration stimulating and measuring system for SPM is built up. The influence of SPM scanners, probes, samples, tip preload stresses and open/close loop tip-sample interactions are tested on SPM VRR. Both in theory and on experiment, it＇s proved that SPM VRR has correlations with the effective mass and elastic coefficient of cantilever, air damping coefficient, contacting elastic coefficient and contacting damping coefficient between tip and sample, etc. As for SPM parts specifications, the vibration rejecting ability can be improved by shorter scanners, longer cantilever probes, softer sample surfaces, bigger tip preload stresses and close loop control for tip-sample interaction.