The Binding Energy of Vacancy Clusters Generated by High-Energy Ion Implantation and Annealing in Silicon

We have measured the evolution of the excess vacancy region created by a 2 MeV, 1016/cm2 Si implant in the silicon surface layer of silicon-on-insulator substrates. Free vacancy supersaturations were measured with Sb dopant diffusion markers during post- implant annealing at 700, 800, and 900C, while vacancy clusters were detected by Au labeling. We demonstrate that a large free vacancy supersaturation exists for short times, during the very early stages of annealing between the surface and the buried oxide (1 m below). Afterwards, the free vacancy concentration returns to equilibrium in the presence of vacancy clusters. These vacancy clusters form at low temperatures and are stable to high temperatures, i.e. they have a low formation energy and high binding energy.