Nanoscale lithography with frequency-modulation atomic force microscopy

Abstract

A lithographic method to draw nanoscale structures by repetitive depositions of the tip material by field evaporation has been developed based on frequency-modulation atomic force microscopy (FM-AFM). Because of high stiffness of quartz tuning forks, a force sensor in the AFM, unwanted mechanical contact of the AFM tip with the substrate was prevented. Precise control of the tip-substrate gap distance with FM-AFM and a gold tip sharpened with focused ion beam enable us to deposit gold dots as small as approximately 20 nm in size and construct nanoscale patterns.