Sb Pile-up at Oxide/Si Interface during Drive-in Diffusion after Predeposition Using Doped Oxide Source

Abstract

The Sb pile-up phenomenon during drive-in diffusion at 1000°C in N2, dry O2 and wet O2 atmospheres after predeposition was investigated. The Sb surface concentration during the predeposition using doped oxide source was about 7×1018 cm-3 which is lower than the solid solubility. From the measured Sb depth profiles in both Si and oxide, it was found that the Sb pile-up layer is located at the oxide side of the oxide/Si interface, the Sb peak concentration of the layer is of the order of 1019 cm-3 irrespective of diffusion atmospheres, and the layer is not a single monolayer but above 4 nm in width. The Sb amount taken into oxide during drive-in diffusion increases with the increase in oxide thickness and Sb surface concentration in Si. For drive-in diffusion in N2 ambient, the Sb pile-up amount in oxide is nearly saturated within the initial 10 min, while for the diffusion in dry O2 ambient, this occurs within 30 min.