Electric Field Based Simulations of Local Oxidation Nanolithography using Atomic Force Microscopy in a Level Set Environment

During the last decades it has been shown that non-contact AFM can be used as an efficient lithographic technique capable of manufacturing nanometer sized devices on the surface of a silicon wafer. The AFM nanooxidation approach is based on generating a potential difference between a cantilever needle tip and a silicon wafer. A water meniscus builds up between the tip and the wafer, resulting in a medium for oxyions to move due to the high electric field in the region. A simulator for nanooxidation with non-contact AFM tools, implemented in a Level Set environment, was developed. The presented model uses empirical equations for the height and half-width of an AFM nanodot or nanowire with a physics based shape model. The shape model uses a particle distribution directly derived from the surface charge density, generated on the silicon surface due to the strong electric field.