SURFACE AND BULK DIFFUSION OF ADSORBED NICKEL ON ULTRATHIN THERMALLY GROWN SILICON DIOXIDE

The surface diffusion of Ni on a thermally grown silicon dioxide ultra thin film (5-50 angstrom), and the bulk diffusion of Ni through the si licon dioxide film into the single crystal silicon substrate have been studied by XPS, HREELS, LEED and AFM. Nickel agglomeration on the oxi de surface occurs in the 100-850 K regime, while bulk Ni diffusion thr ough the thin oxide layer to the Si substrate occurs in the 700-1050 K regime. The onset of bulk Ni diffusion is dependent on the oxide thic kness; thicker oxides reduce the rate of Ni penetration [1]. Above 950 -1100 K, the oxide layer desorbs leaving nickel silicide on silicon.