Resolving mass spectral overlaps in atom probe tomography by isotopic substitutions – case of TiSi15N
Journal article, 2018

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 14 N + and 28 Si 2+ peaks as well as the 14N 2 + and 28 Si + peaks. By substituting 14 N with 15 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 Ti 1- x Si x 15 N 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.

Mass spectral overlap

Atom probe tomography (APT)

Titanium silicon nitride (TiSiN)

Time-of-flight mass spectrometry (TOFMS)

Isotopic substitution

Isotope enrichment


D. Engberg

Linköping University

L. J. S. Johnson


J. Jensen

Linköping University

Mattias Thuvander

Chalmers, Physics, Materials Microstructure

Lars Hultman

Linköping University


0304-3991 (ISSN)

Vol. 184 51-60

Subject Categories

Inorganic Chemistry

Atom and Molecular Physics and Optics

Other Chemistry Topics



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