Alkanethiol self-assembled monolayer on copper polycrystalline thin films: Influence on resistivity

Abstract

Thin polycrystalline copper films of low surface roughness and low electrical resistivity were deposited by physical vapor deposition onto mica at room temperature and in thicknesses ranging from 10 to 80 nm. The crystalline orientation of the films was mainly in the [111] direction, with a surface roughness of under 8.0 nm for thicker films. The copper films were coated with dodecanethiol (DDT), CH3(CH2)10HS by direct immersion into a millimolar solution of the molecules in ethanol for 20 h. Self-Assembled monolayers (SAMs) formation was observed based on XPS studies. The results showed that DDT-SAMs were an effective barrier against the oxidation of the metallic surface, and the resistivity increased between 15% and 70% over the bulk value, depending on the film thickness.