Scanned probe microscope tip characterization without calibrated tip characterizers

Abstract

In scanned probe microscopy the image is a combination of information from the sample and the tip. In order to reconstruct the true surface geometry, it is necessary to know the actual tip shape. It has been proposed that this shape may be reconstructed from images of ‘‘tip characterizer’’ artifacts of independently known shape. The requirements for this strategy—dimensional uncertainty and instability of the characterizer small compared to the tip size—are not trivial. An alternative is ‘‘blind reconstruction,’’ which requires no information about the characterizer geometry apart from that contained within its image, yet produces an outer bound on the tip shape which for appropriately chosen characterizers is a good approximation. With blind reconstruction dimensional instability of characterizers is less problematical, and characterizer measurability is no longer a constraint, so more complex distributed characterizer geometries may be advantageously employed. In situations where part of a characterizer has a known shape, blind reconstruction and the known-characterizer method may be combined.