H AND D DEPTH PROFILES IN IMPLANTED AND LASER-ANNEALED BERYLLIUM

The thermodynamic properties of H and D implanted in Be to different fluences have been investigated by laser flash desorption. From the evolution of the H and D depth profiles following laser annealing, different detrapping/diffusion processes in matter are proposed. The experimental results were compared to those obtained from a finite element time resolved simulation code. Two different processes depending on the H or D fluence can be inferred: at low fluence, a 1.7 eV/molecule detrapping energy and a fairly high effective diffusion coefficient have to be involved, while at high fluence the detrapping energy is less-than-or-equal-to 1 eV/molecule and an extremely rapid migration have to be considered. The transition between these two regimes corresponds approximately to the fluence for which blistering becomes detectable.