title: AFM tip characterization by using FFT filtered images of step structures.
abstract: The measurement resolution of an atomic force microscope (AFM) is largely dependent on the radius of the tip. Meanwhile, when using AFM to study nanoscale surface properties, the value of the tip radius is needed in calculations. As such, estimation of the tip radius is important for analyzing results taken using an AFM. In this study, a geometrical model created by scanning a step structure with an AFM tip was developed. The tip was assumed to have a hemispherical cone shape. Profiles simulated by tips with different scanning radii were calculated by fast Fourier transform (FFT). By analyzing the influence of tip radius variation on the spectra of simulated profiles, it was found that low-frequency harmonics were more susceptible, and that the relationship between the tip radius and the low-frequency harmonic amplitude of the step structure varied monotonically. Based on this regularity, we developed a new method to characterize the radius of the hemispherical tip. The tip radii estimated with this approach were comparable to the results obtained using scanning electron microscope imaging and blind reconstruction methods.
authors.affiliation: Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001, PR China; Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001, PR China. Electronic address: yanyongda@hit.edu.cn.
authors.forename: Yongda
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001, PR China; Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001, PR China.
authors.forename: Bo
authors.initials: B
authors.lastname: Xue
authors.affiliation: Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001, PR China.
authors.forename: Zhenjiang
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001, PR China.
authors.forename: Xuesen
authors.initials: X
authors.lastname: Zhao
keywords: Atomic force microscope; Spectrum of image; Step structure; Tip characterization