Auger electron spectroscopy study of interdiffusion, oxidation and segregation during thermal treatment of NiCr/CuNi(Mn)/NiCr thin films

The effect of annealing on sputter deposited thin-films NiCr/CuNi(Mn)/NiCr is studied by Anger electron depth profiling. The samples were annealed to maximum temperatures of 300 degrees C to 550 degrees C and investigated at ambient temperature. Auger transitions of Cu and Ni are separated by target factor analysis, principal component analysis and linear least squares fit to standard spectra. For the CuNi(Mn) layer in the as-received state AES results shows a Cu depletion caused by bombardment induced segregation. After annealing the measured Cu concentration has increased due to Ni diffusion to the interfaces. The NiCr layer is degraded with increasing annealing temperature due to formation of a chromium oxide and diffusion of Ni from the CuNi(Mn) layer. A sequence with nominal compositions near Cr(2)Ni, CrNi and CrNi(2) is found. At the NiCr/CuNi(Mn) interface an interdiffusion zone phase Ni(0.6)Cr(0.2)Cu(0.2) is formed. (C) 1999 Elsevier Science B.V. All rights reserved.