Preparation and characterization of CuN-based ternary alloy films using Cr or Zr for stabilizing N

The surface hardening of Cu is an effective way to keep good electrical conductivity and increase chemical inertness. Here, Cr and Zr are introduced into Cu films to stabilize N and increase the film hardness. CuN-based alloy films are prepared on single-crystal Si(100) substrates using magnetron sputtering. Cu(Cr, N) films are mainly composed of Cu and Cr2N nanocrystals while Cu and Zr2N nanocrystals compose Cu(Zr, N) films. The thermal stability of the ternary films comes from the strong interaction between Cr (or Zr) and N which is contributing to the generation of stable nitrides. In terms of resistivity and hardness, the Cu(Cr, N) and Cu(Zr, N) films prepared at the N2/Ar ratio of 1/10 show preferable properties. Especially, the Cu86.1Zr6.1N7.8film exhibits the highest hardness (∼4.7 GPa) and lowest resistivity (63.6 µΩ·cm). The chemical inertness of Cu film can also be improved by adding Cr–N and Zr–N. These ternary films are expected to apply for Cu surface nitrogenization.