Structure and surface composition of NiCr sputtered thin films

Thin films of nichrome were deposited by d.c. sputtering of a target (80%Ni 20%Cr w.t) by Ar+ions at a working pressure of 10-1 Pa and at room temperature. The phase composition and grain size were studied by X-ray Diffraction (XRD), while the surface chemical composition was determined by Low Energy Ion Scattering (LEIS). Analysis of phase composition showed that the NiCr thin films were a solid solution of chromium in a nickel matrix with increased nickel lattice parameters. LEIS analysis showed the presence of Ni Cr and O in the first atomic layer. There is a strong suspicion that surface passivation occurred by forming Cr2O3 oxide at the surface.