Molecular dynamics simulation method for calculating fluence-dependent range profiles

Molecular dynamics has proven to be successful in calculating range profiles for low energy (keV) ions implanted into crystalline materials. However, for high fluences the structure of the material changes during the implantation process. The crystalline material becomes amorphized, which changes the range profiles. This damage build-up process has usually been taken into account with probabilities for changing the crystal structure during the simulation, and typically only BCA methods have been used. We present a fast MD method that simulates the damage build-up process in silicon, without bringing any free parameters to the simulation. Damage accumulation during the implantation is simulated by changing the material structure in front of path of the incoming ion. The amorphization level at each depth is proportional to the nuclear deposited energy in that depth region. The amorphization states are obtained from MD simulations of cascade damage. Silicon was used as a target material because of the large amount of experimental data available. Comparison with the simulations show a good agreement for a wide range of experiments