Migrations of Interstitial Atoms in Semiconductors (Surface Diffusion and Kick-Out Mechanism)

AbstractGe and Zn atoms were introduced into the unirradiated regions of Si at 150°C and GaAs wafers at 50°C, respectively by using the electron-beam doping method. The surfaces of Si and GaAs substrates were covered partially by the overlayers of Ge and Zn sheets, respectively. The only surfaces of the Ge and Zn sheets were irradiated locally. with high energy electrons at 7MeV with the fluences of 5×1017 – 1×1018 electrons cm-2 . Even at a distance of ~10mm from the irradiated overlayers in the Si and GaAs substrates, Ge and Zn atoms respectively, whose interstitials may migrate the unirradiated regions, were detected by SIMS measurements. PL signal due to band-to-acceptor (ZnGa ) transition at 1.48eV becomes observable after annealing at 800°C for 20mm in the unirradiated GaAs region, which is separated from Zn sheet by nearly 10mm.