Damage formation in Si under irradiation with PF$^+_n$ ions of different energies

The generation of structural damage in silicon irradiated with atomic (P$^+$) and molecular (PF$^+_4$) ions is experimentally studied in a wide range of ion energies. A strong molecular effect caused by the over-lapping of collision cascades created by atoms comprising a molecular ion is revealed near the sample surface in all cases considered. Theoretical assessments of the depths of possible nonlinear process have shown good agreement with experimental data. Calculations have also shown that the role of nonlinear energy spikes decreases with an increase in the energy of the ion.