A study was made of the vacancy formation energy in Si crystals evaporated with various metals. Specimens were cut from a high-purity float-zone crystal, evaporated with various metals and heated in H; followed by quenching in water. Instead of the vacancy concentration, the optical absorption coefficient due to VH4 (a complex of one vacancy and four H-atoms) was measured. The vacancy formation energy in these specimens was found to be much smaller than that in high-purity specimens and that in specimens doped with metallic impurities in an isolated state (solid solution). After heating for a short time, the vacancy concentration exhibited a spatial distribution which decreased with distance from the interface. This suggested that the vacancy source was the interface region.

Vacancy Formation Energy at Metal-Silicon Interface Region. M.Suezawa, K.Saitoh, K.Kojima, A.Kasuya: Japanese Journal of Applied Physics, 2005, 44[19], L593-5