Engberg David L J, Johnson Lars J S, Jensen Jens, Thuvander Mattias, Hultman Lars
Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping SE-581 83, Sweden.
Sandvik Coromant, Lerkrogsvägen 19, Stockholm SE-126 80, Sweden.
Ultramicroscopy. 2018 Jan;184(Pt A):51-60. doi: 10.1016/j.ultramic.2017.08.004. Epub 2017 Aug 12.
Mass spectral overlaps in atom probe tomography (APT) analyses of complex compounds typically limit the identification of elements and microstructural analysis of a material. This study concerns the TiSiN system, chosen because of severe mass-to-charge-state ratio overlaps of the N and Si peaks as well as the N and Si peaks. By substituting N with N, mass spectrum peaks generated by ions composed of one or more N atoms will be shifted toward higher mass-to-charge-state ratios, thereby enabling the separation of N from the predominant Si isotope. We thus resolve thermodynamically driven Si segregation on the nanometer scale in cubic phase TiSiN thin films for Si contents 0.08 ≤ x ≤ 0.19 by APT, as corroborated by transmission electron microscopy. The APT analysis yields a composition determination that is in good agreement with energy dispersive X-ray spectroscopy and elastic recoil detection analyses. Additionally, a method for determining good voxel sizes for visualizing small-scale fluctuations is presented and demonstrated for the TiSiN system.
