Dependence of damage efficiency of ions in diamond on electronic stopping

Natural diamond single crystals were irradiated at room temperature with 75 keV carbon and 80 keV argon ions at fluences exceeding the graphitization dose. The resulting damage depth profiles before and after rapid annealing at 1500 K were obtained by α-particle channeling analysis. Measurements were done both at back- and forward scattering angles using conventional surface barrier detectors and an electrostatic analyzer system, respectively. Boundary positions of the graphitic layers were determined and compared with the corresponding depth-dependent elastic and inelastic energy deposition graphs to extract critical damage energy densities. The obtained values increase strongly with inelastic energy deposition rate, indicating a significant reduction of the ions' damage efficiency due to irradiation induced annealing by electronic stopping.