Silicon structures for in situ characterization of atomic force microscope probe geometry

Atomic force microscopy (AFM) is increasingly relied on to image and measure micron and submicron scale surface features. Consistent interpretation of AFM information is, however, difficult if the geometry of the probe is not known. In this work, the fabrication of funnel-like structures and their use in probe characterization were developed from a proof of concept to readiness for field testing. The specifications that determine the structure's sensitivity to probe shape were identified. The fabrication was tailored to yield large reproducible arrays (> 100 x 100 structure). The geometry of the structures was characterized using low voltage scanning electron microscopy (SEM) techniques. Testing in intermittent contact mode has shown that the structures are stable even at high forces for multiple scans under various conditions. An algorithm was developed that calculates the probe geometry from an image of the structure. The sensitivity of the structures to probe shape was tested by comparing SEM images of probe shape to the probe geometry calculated from the AFM images of the structures. From this analysis it was determined that the structures are sensitive to the cone angle of the probe to within 5 degrees and to the probe radius to within 50 nm. (C) 1996 American Vacuum Society.