Surface and mechanical characterization of TaN-Ag nanocomposite thin films

TaN-Ag nanocomposite thin films with Ag nano-particles dispersed in TaN matrix and surface were prepared by reactive co-sputtering of Ta and Ag in the plasma of N-2 and At. After deposition, the films were annealed using RTA (Rapid Thermal Annealing) at 350 degrees C for 2, 4, 8 min respectively to induce the nucleation and growth of Ag particles. C-AFM (Conductive-atomic Force Microscopy) and SSPM (Surface Scanning Potential Microscopy) were applied to characterize the emergence of Ag nano-particles on the surface of TaN-Ag thin films in this study. It is seen that Ag nano-particles may emerge in the matrix and on the surface of TaN and, possibly, grow. The results are compared with that obtained by FE-SEM (field-emission scanning electron microscopy). After comparison, C-AFM and SSPM are seen to be useful in characterizing the emergence and distribution of Ag particles. The results also show that the films' hardness and Young's modulus values would increase or decrease with the increase of annealing time, depending on Ag content and annealing time. This behavior is similar to that of TaN-Cu nanocomposite film. In addition, the increase of wear resistance of these coatings is proved. (c) 2007 Elsevier B.V. All rights reserved.