Full three-dimensional simulation of focused ion beam micro/nanofabrication

Abstract

2D focused ion beam simulation is only capable of simulating the topography where the surface shape does not change along the third dimension, both in the final result and during processing. In this paper we show that a 3D topography forms under the beam even though the variation in the final result along the third direction is small. We present the code AMADEUS 3D (advanced modelling and design environment for sputter processes), which is capable of simulating the surface topography in 3D space including angle-dependent sputtering and redeposition. The surface is represented by a structured or unstructured grid, and the nodes are moved according to the calculated sputtering and redeposition fluxes. In addition, experiments have been performed on nanodot formation and box milling for a case where a 3D temporary topography forms. The excellent agreement validates the code and shows the completeness of the model.