A multi-ion plasma FIB study: Determining ion implantation depths of Xe, N, O and Ar in tungsten via atom probe tomography.

In this study atom probe tomography was used to determine the implantation depth of four different plasma FIB ion species - xenon, argon, nitrogen, and oxygen - implanted at different acceleration voltages. It was found that lowering the beam energy reduces the implantation depth, but significant implantation was still observed for N, O and Ar at beam energies as low as 2 kV. Furthermore, nitrides and oxides were observed that were formed when using N and O. Xe had the lowest implantation depth compared to Ar, N and O when using the same conditions. No Xe ions were detected in the sample prepared at 2 kV. Experimentally-determined implantation depths were compared to calculated implantation depths. The experiments exhibited deeper-than-predicted ion implantation into the microstructure, but lower-than-predicted ion concentrations.