New partition factor calculations for evaluating the damage of low energy ions in silicon

The analysis of Lindhard's calculations of the partition factor Q and the corresponding factor obtained from the SRIM calculations shows that both significantly underestimate the energy losses to damage for ions below 100 keV. This is the result of their overestimation of the electronic losses of such ions in matter. New partition factor for low energy (< 500 keV) ions in silicon is calculated by a specially developed Monte Carlo code. The new Q-values are significantly larger than previous results. This brings them to a good agreement with the experimental data including recently published precise ionization measurements using silicon based photodiodes. We used the new partition factor for calculating the non-ionizing energy losses (NIEL) for electrons and protons. The resulted NIEL values are larger by 15% on the average compared to the published calculated data.