  The creation of nitrogen-vacancy centres in diamond is nowadays well
controlled using nitrogen implantation and annealing. Although the
high-resolution placement of NV centres has been demonstrated using either
collimation through pierced AFM tips or masks with apertures made by electron
beam lithography, a targeted implantation into pre-defined structures in
diamond may not be achieved using these techniques. We show that a beam of
nitrogen ions can be focused to approximately 100 nm using focused ion beam
(FIB) technology. The nitrogen ion beam is produced using an electron cyclotron
resonance (ECR) plasma source. Combined with a scanning electron microscope,
the nitrogen-FIB offers new possibilities for the targeted creation of single
defects in diamond. This maskless technology is suitable for example for the
creation of optical centres in the cavities of photonic crystals or in diamond
tips for scanning magnetometry. Finally, we further show that by changing the
gas source from nitrogen to xenon, standard FIB milling capabilities are also
available within the same tool.
