Study of the effect of implantation temperature on the migration behaviour of Xe implanted into glassy carbon.

Abstract

The effect of implantation temperature on the migration behaviour of xenon (Xe) implanted into glassy carbon and the effect of annealing on radiation damage retained by ion implantation were investigated. Glassy carbon substrates were implanted with 320keV Xe+ to a fluence of 2×1016cm-2. The implantation process was performed at room temperature (RT) and 100°C Some of the as-implanted samples were isochronally annealed in vacuum at temperatures ranging from 300°C to 700°C in steps of 100°C for 10h. The as-implanted and annealed samples were characterized using Rutherford backscattering spectrometry (RBS) and Raman spectroscopy. The RT implanted depth profiles indicated that the migration of Xe towards the surface of glassy carbon was accompanied by a loss of Xe ions. The samples implanted at 100°C indicated no diffusion or loss of Xe after annealing at 300°C. However, annealing at temperatures ranging from 400°C to 700°C resulted in a slight shift in the Xe profile tail-end towards the bulk of glassy carbon. The diffusion coefficients (D) in the temperature range of 300°C-700°C for the RT and 100°C implanted samples, activation energies (Ea), and pre-exponential factors (Do), were extracted. The values of D ranged from (9.72±0.48)×10-21 to (1.87±0.09)×10-20m2/s with an activation energy of (6.25±0.31)×10-5eV for RT implanted samples, and the samples implanted at 100°C, D ranged from (3.85±0.19)×10-21 to (6.96±0.34)×10-20m2/s with activation energy of (4.10±0.02)×10-5eV. The Raman analysis revealed that implantation at the RT amorphised the glassy carbon structure while the samples implanted at 100°C showed mild damage compared to RT implantation. Annealing of the RT-implanted sample resulted in some recovery of the damaged region as a function of increasing annealing temperature.