Metallisation of porous silicon by chemical vapour infiltration and deposition

Thin cobalt layers have been grown on and in porous silicon by chemical vapour infiltration and deposition using HCo(CO)(4). The process can be controlled to give a capping layer with or without metal in the pores. Thin coats on the pore walls have been measured to depths of several mu m and thick coats to depths of 0.1 mu m. Results from mass spectroscopy indicate that when a cobalt hydride precursor molecule decomposes on a pore wall it releases its hydrogen atom accompanied by three from the pore wall, so forming direct metal-silicon bonds.