Methods of depositing thin, low dielectric constant layers that are effective diffusion barriers on metal interconnects of semiconductor circuits are described. A self-assembled monolayer (SAM) of molecules each having a head moiety and a tail moiety are deposited on the metal. The SAM molecules self-align, wherein the head moiety is formulated to selectively bond to the metal layer leaving the tail moiety disposed at a distal end of the molecule. A dielectric layer is subsequently deposited on the SAM, chemically bonding to the tail moiety of the SAM molecules.