Using defined structures on very thin foils for characterizing AFM tips

Knowledge of tip geometry is necessary for reproducible atomic force microscope (AFM) measurements. This is particularly important for measurements in contact mode, in which a certain wear of the tip will always occur. For small or flat structures or for structures of larger dimensions, knowledge of the tip radius and the entire tip geometry is important. Additionally, the tilt of the tip in relation to the sample is of importance. Normally, very complicated lithographically manufactured structures for tip characterization are used. In contrast, the structures shown in this work are very simple. For measuring the tip geometry very thin foils patterned by focused ion beam (FIB) were used. In this work we demonstrate the possibility of determining the AFM tip geometry and the tilt based on several different large structures. A proven algorithm was developed for the reconstruction of the tips. The shape of FIB-structured foils was determined by electron microscopy prior to AFM measurements. This new method for determining tip shape is also presented as it compares to other current methods. In this case a discussion on the stability and advantages of the new method is presented. (c) 2007 Elsevier B.V. All rights reserved.