Analysis on vibration rejection ratio of scanning probe microscope

Abstract

In order to investigate the influence of external vibration on the tip-sample interaction in scanning probe microscope, a concept, vibration rejection ratio (VRR), was proposed by Thompson et al. In the present article, a concise theoretical background was introduced, a vibration stimulating and measuring system for SPM was built up, and an experimental research of the influence on SPM VRR was carried out with different SPM probes, samples, tip preloads, and open/close loops of tip-sample interaction. Based on the experiments, it was proved that SPM VRR had correlations with the spring constant, the air damping constant, the effective mass of the cantilever, the contact spring constant, the contact damping constant between tip and sample, etc. Being different from the traditional theoretical analysis, other than the resonant frequency, a “leading coefficient” was proposed to describe the VRR. A conclusion was drawn after an experimental analysis that SPM’s vibration rejecting ability can be improved by longer cantilever probe, softer sample surface, greater tip preload, and close-loop control for tip-sample interaction. More attention should be paid to a proper combination of the above parameters.