A full-scale simulation approach for atom probe tomography

A versatile approach for simulation of APT measurements is presented. The model is founded on a Voronoi cell partition of 3D space. The partition is used in dual role: First, the atomic structure of the field emitter is depicted in a one to one relationship by single WignerSeitz cells. Second, the construction of an adaptive tetrahedral mesh enables solving the Poisson equation on length scales covering seven orders of magnitude. Ion trajectories are computed in full-length comparable to experiments. Contrary to former simulation approaches the sequence of desorbing atoms is determined by field-induced polarization forces. Both results for cubic lattices in < 001 >, < 011 >, and < 111 > orientation are presented and the simulation of an APT measurement of a complex crystalline/amorphous layer structure is demonstrated. The example of a grain boundary addresses the new possibility of constructing models with structural defects. In this case, the simulation reveals strong artifacts in the reconstruction even if homogenous evaporation threshold is assumed. (C) 2013 Elsevier B.V. All rights reserved.