Ultra shallow junctions (depths <0.1 μm) are required for future generations of silicon devices. This requires either very low energy ion implantation (<1 keV for B for the shallowest of implants) or the use of heavier implanted species (either elemental or molecular). Many commercial implanters have problems operating at such low terminal voltages. For many years molecular ions, in particular BF 2 + , have been used to transport low velocity boron at higher energies, enabling the use of conventional implanters in the production of shallow junctions. However, with ever shrinking scales the energies required even for BF 2 are becoming too low. The investigation here is to look at the alternative heavier halides and decaborane as possible alternatives to allow continued use of conventional ion implanters. We use a molecular dynamics simulation to see if we can find any evidence of non-linear behaviour from the use of such molecular species for implantation, thereby making the modelling and simulation of such implants more complex than more conventional implantation. The simulation results presented suggest that there is no evidence of non-linear behaviour and all the standard parameters of implantation - ion ranges and displacements of silicon atoms - change in a well predicted manner.