Simulation of Radiation Damage in Solids

A combined theoretical and experimental study of primary recoil spectra effects or radiation damage in silicon is presented. Calculations determined how the damage energy is partitioned into free defects and cascades by fast collisions. The theory also showed that on a time scale ~10-14 sec. a very weak mass dependence of the lattice damage is to be expected. Channeling experiments were then performed on <111> single crystal silicon implanted with 1.0 MeV 20Ne, 0.5 MeV 4He and 75 keV 1H. Energies and fluences of the ions were matched such that over the first 0.3 ¿m the damage energy deposited and the rate of energy deposition were the same for all species. The experimental data were analyzed assuming that equivalent primary damage states will evolve into statistically equivalent final damage states at high fluences. They confirm that the final damage is essentially independent of the mass of the bombarding ion.