Study on Room-Temperature Wet Oxidation of Silicon Catalyzed by Copper.

Abstract

The anomalously fast growth of the silicon oxide layer at room temperature has been reported for the Cu/Si system. However, the systematical exploration of such a reaction under humidity conditions has not yet been carried out. Through one combination of the experiments and first-principle density functional theory (DFT) simulations, here, we investigate the influence of the imparted Cu atoms in Cu/Si on the oxidation of Si with the presence of H2O. The Cu addition causes the geometric distortion of the Si lattice, which alters the charge transfer to absorbed H2O and decreases its dissociation energy. This results in the experimental formation of much defective SiOx for the Cu/Si system than bare Si under humidity conditions. Furthermore, the presence of such an oxide structure and the catalytic effect of Cu provide the suitable diffusion channels and adsorption sites for the H2O transport and its dissociation. This enhances the oxidation rate of Si consequently and results in the fast growth of the oxide layer on Cu/Si at room temperature.