Comparison of quantitative elemental depth distribution analyses of Ni and Ti in co-sputtered Ni-Ti alloy thin films using MCs+ and M+ secondary ions

Abstract

Compositional uniformity in Ni-Ti thin alloy films, both at the surface and in the depth, significantly enhances their performance in various engineering applications. Quantitative depth distributions of Ni and Ti in magnetron co-sputtered Ni-Ti thin alloy films of various composition and thickness, were determined through an effective depth profiling technique. Secondary ion mass spectrometry (SIMS) was utilized to determine the qualitative elemental depth distribution of Ni and Ti in the films using MCs+-SIMS (Cs+ primary ion beam; MCs+ secondary ions, 'M' is the element of interest) and M+-SIMS (O2+ primary ion beam) approaches. The qualitative depth profiles were converted to quantitative depth profiles using the relative sensitivity factor values determined from the elemental concentrations obtained through energy dispersive x-ray spectroscopy analysis of one of the Ni-Ti thin film taken as reference. Thickness of the deposited films determined by x-ray reflectivity was used for depth scale calibration of SIMS raw profile. A comparison of the analytical capabilities of MCs+-SIMS and M+-SIMS approaches for determining the mean concentration and quantitative depth distribution of elements Ni and Ti in deposited Ni-Ti thin films has been presented.