Automated calibration of the sample image using crystalline lattice for scale reference in scanning tunneling microscopy

This article describes the configuration and application of nn image processing software developed for extracting periodic atomic features from scanning tunneling microscopy (STM) images. This was done with a view to calibrating the lateral and/or vertical scale of images acquired by a STM with two tunneling units, where a crystal can be used as the scale reference with one of the tunneling units. The image processing software was applied to consecutively acquired images of graphite with a size of 150x5 nm. The number of lattices automatically counted in a line scan of 150 nm, scanned in 400 ms, showed a matching of 99.95% from one image to the other. On the other hand, the matching in the feed direction, where image width was only 5 nm, but took 240 s, was 95%. As an example of application of the developed software, nonlinear movement of piezoscanners were readily monitored in the 100 nm order. (C) 1996 American Vacuum Society.