Fabrication of conductive graphitic layers in diamond by multi-species focused ion beam

In this work, we report a systematic study to produce controlled layers of graphite on ‘electronic grade’ diamonds by ion implantation using a multi-species column FIB equipment. The liquid metal alloy ion source (LMAIS) allowed to select among Au++, Ge++ and Si++ species with implant energy of 70 keV. In particular, the process window was defined for each ion species in terms of ion fluence and thermal annealing recipe, identifying the carbon phases by Raman spectroscopy and measuring the developed topographies by atomic force microscopy, before and after a selective etching. Due to the mass difference, different graphite thicknesses were achieved, ranging from 40 to 90 nm. Another possibility is to exploit the selective etching coupled to FIB irradiation for a direct patterning of the diamond surface6, a process in principle able to create nanometric structures embedding CC.