Calibrating the Z-magnification of atomic force microscope below 10 nm by single-atom steps

•Step heights ranging from 0.3 nm to 10 nm were measured and analyzed.•We present an image processing procedure for silicon (111) steps surface.•The measurement uncertainty for step heights ranges from 4.7% to 5.9%.

This study identifies a procedure for the calibration of the Z-magnification of an atomic force microscope below 10 nm by single-atom steps and gives an uncertainty evaluation. A Si(111) surface with periodically arranged single-atom steps was used as a standard reference. The lattice constant of the Si(111) is 0.312 nm, which is traced to SI units through X-ray diffraction. The 33 layers of continuous stacked single-atom steps were scanned and step heights ranging from 0.3 nm to 10 nm were measured and analyzed. The influential factors of calibration for the Z-magnification of an atomic force microscope were identified to estimate the uncertainty according to ISO/IEC Guide 98-3:2008. The relative expanded uncertainties ranged from 4.7% to 5.9%.