SCANNING FORCE MICROSCOPY SIMULATIONS OF WELL-CHARACTERIZED NANOSTRUCTURES ON DIELECTRIC AND SEMICONDUCTING SUBSTRATES

A numerical method for simulating the interaction between a pyramidal tip and a surface with nanostructures is presented. The model takes in to account both attractive van der Waals and repulsive forces with the help of a pairwise Lennard-Jones interaction potential. With this pot ential, the attractive van der Waals forces are only evaluated by usin g the dipolar interaction between the two interacting parts. It is sho wn that the sphere-plane model usually used to mimic a scanning force microscope (SFM) is not accurate enough. The major advantage of the pr esent method is the possibility of simulating SFM images of well-defin ed objects with nanometer dimensions and arbitrary profile on a flat s urface. We give an illustration of this method by making image simulat ions of two dot of silicon and silver on, respectively, Si and MgO sub strates in the so called 'constant distance mode' of imaging. (C) 1998 Elsevier Science B.V.