Influence of Deposition Conditions and Ion-Plasma Treatment of Thin Cobalt Films on Their Electrical Resistivity

The electrical resistivity ρ of cobalt films with a thickness of 10 to 55 nm deposited in different modes of magnetron sputtering on SiO2/Si wafers with their subsequent ion-plasma treatment is investigated. Co films 42 nm thick with minimum ρ of 9.8 µΩ cm, comparable to ρ of a bulk metal, are obtained at a temperature of 600 K. Treating the Co film surface in dense argon plasma with an energy of ions of about 20 eV at room temperature leads to an increase in resistivity, while, at Т ~ 500 K, both a decrease and an increase in ρ are observed. Such a change in resistivity is due to the combined action of ion bombardment and temperature. The mechanism of action of the ion-plasma treatment on the electrical conductivity of the Co film is discussed.