Resistivity measurements of thin film iridium on silicon

The resistivity of thin iridium films deposited on clean silicon substrates was measured by a four point probe technique. A simple electrical model based on parallel current conduction through the Ir film and the silicon substrate is shown to be valid. This allows the Ir contribution to the conduction to be determined. The effect of varying the film thickness from 0.5 to 16 nm caused the measured film resistivity to decrease from 190 to 35×10⁻⁶ Ω cm. This variation agrees well with the variation predicted by the Fuchs–Sondheimer and Lucas models for carrier scattering from the film surfaces.