Hydrophobic fluoroalkylsilane nanolayers for inhibiting copper diffusion into silica

Molecular nanolayers (MNLs) are attractive for suppressing chemical transport and mixing at copper-silica interfaces. Here, we demonstrate that hydrophobic fluoroalkyl moieties enhance the effectiveness of organosilane MNLs to inhibit copper diffusion. Bias thermal annealing of copper-MNL-silica capacitors with MNLs having different fluoroalkyl contents, combined with electron spectroscopy and contact angle measurements, show that the enhanced barrier properties are due to diminished water uptake and curtailed copper ionization. Our results suggest that controlling interface moisture content using hydrophobic moieties can complement copper ion immobilization by hydrophilic groups in MNL barriers.