Thermal Growth of He-cavities in Si Studied by Cascade Implantation

Abstract

AbstractFloat Zone (FZ) silicon samples have been cascade-implanted with helium ions at energies decreasing from 1.9 MeV to 0.8 MeV in steps of 0.1 MeV, with flux maintained between 5 × 1012 and 1 × 1013 He cm-2-1s. The dose was 5×1016 He cm-2 for all the energies except 0.8 MeV where a lower dose of 3×1016 He cm-2 was used. After thermal annealing, the sample was studied by cross section transmission electron microscopy (XTEM) using a Field Emission Gun Microscope (Jeol 2010F). Our results clearly demonstrate that these cavities mainly grow by the Ostwald ripening mechanism. This means a growth by exchange of He and vacancies from smaller to bigger cavities. Further this study provides essential data for resolving the controversy on the growth mechanism governing He-cavities.