Mechanical properties of TaN-Cu nanocomposite thin films

TaN-Cu nanocomposite films were deposited by reactive co-sputtering on tool steel substrates. The films were then annealed using RTA (Rapid Thermal Annealing) at 400 °C for 2, 4, 8 min respectively to induce the nucleation and growth of Cu particles in the TaN matrix and on the film surface. Indentation method was used to examine the mechanical properties of these films. The results confirm that annealing by RTA can cause Cu nano-particles with various dimensions to form on and in the TaN matrix. Consequently, hardness and toughness will change depending on annealing conditions, Cu content, and/or Cu particle density. The strengthening and toughening mechanisms are discussed.