Drift compensation for scanning probe microscopes using an enhanced probe positioning system

摘要

This invention is an enhanced probe positioning technique for Scanning Tunneling Microscopes, Atomic Force Microscopes, and other scanning probe microscopes. The invention has particular application for drift compensation. The invention adds a controllable motion to the probe that is totally independent of the scanning or other probe positioning. If the drift velocity is known, the invention can be used to compensate for the drift. In addition, several implementations are shown for measuring drift velocity. One method has the operator identify a significant feature of the acquired image on separate frames of data. The shift of this pattern or feature, along with the time between frames, can be used to calculate the drift velocity. Two methods are described that utilize the frequency shift of the image spatial spectrum due to the effect of the drift velocity on bi-directional scans. Another method is described that derives drift velocity and direction from the correlation of separate frames of data. The invention can also be used to compensate for predicted drift, such as the drift after a scan area offset.