Field Ion Emission in an Atom Probe Microscope Triggered by Femtosecond-Pulsed Coherent Extreme Ultraviolet Light

3D pulsed laser atom probe tomography (APT)  is an atomic scale materials characterization and 3D imaging method utilizing ultrafast pulses to induce photon assisted field ion evaporation in certain materials. Currently, modern APT measurements employ coherent, pulsed near ultraviolet (NUV) light to induce the field ion evaporation necessary for APT measurements, as higher photon energies have been observed to increase data quality. However, photon assisted field ion evaporation with energies above NUV has never been demonstrated on APT substrate materials, which is a requirement to perform APT. In this paper, the authors utilize a KMLabs Ti:Sapphire amplifier system to drive a “XUUS” ultrafast, coherent, extreme ultraviolet (EUV) source with wavelengths as low as 29.6 nm to demonstrate pulsed EUV radiation-assisted field ion emission of substrate atoms in amorphous SiO₂ samples. The ability to apply pulsed EUV radiation to photon assisted field ion evaporation not only broadens the available materials capable of measurement with APT, but also provides the ability to observe additional athermal ionization mechanisms not present in most materials with NUV measurements.

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