XTEM study of Ni gettering to H-implantation-induced nanocavities in SIMOX

Nanocavities were generated in the silicon substrate of the SIMOX wafer by H implantation and annealing. Different dose of Ni impurities were introduced in the Si overlayer by implantation. The structures of nickel decorated voids and Ni precipitates epitaxially grown in the void band were studied. NiSi/sub 2/ precipitates were observed both in the nanocavities and at the residual defects created by H implantation. The microstructure of Ni precipitate depended on whether there were voids nearby. Without cavities in the vicinity, dislocations were observed in the neighborhood of the precipitate, whereas no dislocation was detected around the precipitate when there are many nanocavities in the neighborhood. Due to the competitive gettering effect of BOX, the gettering efficiency of Ni to nanocavities in SIMOX is lower than that in bulk Si.