Standardized procedure for calibrating height scales in atomic force microscopy on the order of 1 nm

Abstract

We propose a standard stepped sample and specify a procedure for determining the step height for height-scale calibration of atomic force microscopy (AFM) instruments on the order of sub-nm to nm. The stepped Si(111) surface structure was confirmed to be the most appropriate for the standard sample by a series of round-robin measurements carried out by a group comprising AFM instrument manufacturers and user organizations. By specifying a standard measurement procedure, the mean standard deviation of the step heights is decreased by 50%. It is also confirmed that the measured Si step height is accurate to ±5%, which is consistent with the accuracy obtained for higher step standard samples. A prototype common data processing software program containing the algorithm of the specified procedure was used to allow direct comparison of the untreated measurement data from each organization.