Selective deposition of CVD iron on silicon dioxide and tungsten

The preferential deposition of CVD iron on silicon dioxide (SiO2) surfaces over tungsten (W) surfaces has been demonstrated. Depositions carried out on patterned W/SiO2 substrates have shown that layers up to a thickness of 180 nm with a resistivity value of 19 μΩ cm can be successfully deposited, exhibiting 100% selectivity; i.e. 180 nm of iron was deposited on the oxide surface whilst no deposition occurs on the tungsten surface. For longer deposition times, some iron nucleation was observed on the tungsten surface. It was found that the thickness of the deposited iron layer was inversely proportional to the exposed silicon dioxide surface area.