Sputter Profiling Through Ni/Fe Interfaces by Auger Electron Spectroscopy

Sputter characteristics of nickel-iron systems in the form of layer interfaces and bulk alloy films have been studied by Auger electron spectroscopy. The sputter rates for pure nickel and iron and their alloys have been determined and are independent (within 10%) of the grain size and film composition. The various factors that contribute to the broadening of depth profiles have been examined. The initial broadening of 4.5 nm at zero overlayer thickness is mainly attributed to the effects of electron escape depth and compositional mixing due to ion bombardment. For thin films, the depth-dependent broadening induced by sputter damage has an approximately exponential dependence on the overlayer thickness. For thick films, this broadening is estimated to be about 10% of the sputter distance. The effect of ion-induced surface compositional mixing as a function of incident Ar
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ion energy has been studied by taking advantage of the different sampling depths of low and high energy Auger electrons.