Ga contamination in silicon by Focused Ion Beam milling: Dynamic model simulation and Atom Probe Tomography experiment

Abstract

Focused Ion Beam (FIB) milling is a widely used and important technique to prepare Transmission Electron Microscopy (TEM) lamella samples. However, it unavoidably introduces contamination in the samples like implanted ions. While the conventional ion-solid simulation model, Binary Collision Approximation (BCA), is unable to describe the FIB process, a dynamic BCA model is used in this study to predict the level of Ga implantation along the substrate depth. The FIB process involves significant material transport and local composition alteration, which requires a dynamic model for simulation. To validate the dynamic BCA model's application on simulating the FIB process, atomic level composition analysis Atom Probe Tomography (APT) is performed on Ga FIB processed silicon samples. The experimental data confirm that the dynamic BCA model is capable to predict FIB induced Ga ion implantation in silicon samples.