Range distributions and thermal behaviour of Bi implanted into kcl and Al/KCl bilayer structures

Abstract 300 keV Bi + was implanted into an Al(610 A)/KCl bilayer structure, and for comparison into a pure KCl single crystal. The Bi depth distribution, measured by RBS, agrees well with theoretical predictions (TRIM) in both cases. Thermal annealing yields two stages: first, up to 200°C, the Bi distribution changes rapidly, probably due to diffusion enhanced by radiation damage in KCl. At higher temperatures, those defects anneal out, so that essentially regular diffusion governs the depth profiles up to 500°C, and an Arrhenius diagram can be given. For the Al/KCl bilayer structure, we find retarded diffusion in a rather broad interval around the interface, in agreement with previous findings for Bi in the Al/Ti bilayer structure.