Improved atomic force microscope images using microcantilevers with sharp tips

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Abstract
Novel force‐sensing microcantilevers with sharp tips have been used to obtain atomic force microscope images of atomically flat, layered compounds as well as microfabricated samples with large‐scale topographies. When imaging atomically flat samples using cantilevers with sharp protruding tips, atomic corrugations are observed more consistently and with a higher signal‐to‐noise ratio than in the absence of tips. Some asymmetric distortions arise when tipped cantilevers are used with forces larger than 10−7 N. Side by side comparisons of images of rough samples obtained using cantilevers with and without tips reveal that the presence of a sharp tip yields superior image quality of vertical features and trenches. The cantilever assembly is a microfabricated, silicon nitride cantilever with an integral, single‐crystal silicon tip. The silicon tip is self‐aligned to the end of the cantilever and is created by a process which simultaneously fabricates and sharpens the silicon tip. Initial transmission electron microscopy studies show that the single‐crystal silicon tips have radii of curvature of 220–400 Å.