Transport of Low-Energy Ions in Gallium Nitride

The transport of He, O, and Ar ions with energies of 10, 25, 50, and 100 keV in a 500 nm thick gallium nitride layer was investigated by using Monte Carlo simulations. The calculations were performed with SRIM/TRIM and Geant4. Depth profiles of ionizing and non-ionizing energy losses, as well as projected and radial range characteristics, were compared. For He ions, ionizing energy losses dominate over the entire energy range considered, whereas increasing the mass of the incident ion leads to a larger fraction of the energy being transferred to atomic collision cascades. For Ar ions, non-ionizing energy losses exceed ionizing losses up to 100 keV. The mean absolute differences between the Geant4 and SRIM results are 7.81% for the projected range, 17.44% for ionizing energy losses, and 18.54% for non-ionizing energy losses. These results show that reproducing the spatial scale of ion stopping does not necessarily imply an equivalent description of energy partitioning between the electronic and nuclear channels.