We prepared CuNi (90/10) alloy thin films by D.C. magnetron sputtering on silicon substrates and investigated the film structure as a function of deposition time and sputtering power. The chemical composition (surface and bulk) and microstructure of these deposited films were studied by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), and Neutron Reflectometry (NR). According to XRD studies, all deposited films were composed of single phase CuNi (90/10) alloy with the preferred orientation of the [ 111] direction along the surface normal. Grain sizes increased with the increase in deposition time and sputtering power. SEM and XPS studies confirmed a Stranski-Krastanov-type growth mode. Our XPS analysis revealed the existence of oxides on the surfaces of these films. Nickel was found to be present as NiO and Ni2O3. Furthermore, there was clear evidence for the existence of CuO along with Cu2O. XPS and NR measurements confirmed the (90/10) alloy composition of our CuNi films. (C) 2016 Elsevier B.V. All rights reserved.