Nanometer-scale isotope analysis of bulk diamond by atom probe tomography

• Atom probe tomography of bulk diamond is reported
• Controlled carbon atom evaporation was achieved
• The vertical concentration profile of a nitrogen doping layer, created by ion implantation, was imaged with nanometer spatial resolution
• No evidence was seen for ion channeling

Atom-probe tomography (APT) combines field emission of atoms with mass spectrometry to reconstruct three-dimensional tomograms of materials with atomic resolution and isotope specificity. Despite significant recent progress in APT technology, application to wide-bandgap materials with strong covalent bonds has remained challenging or low yielding. Here we report APT measurements on bulk diamond grown by chemical vapor deposition. Using a conductive substrate in combination with laser-pulsing, carbon atoms could be controllably field evaporated and tomograms containing up to 6 million atoms could be reconstructed. We have subsequently applied the technique to iage the depth distribution of a sub-surface nitrogen δ-layer with nanometer spatial resolution. With future development, the technique may enable detailed characterization of dopants in diamond at an atomic level, which would be of great interest to the many scientific and industrial applications exploiting the unique properties of the material.

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