Ion implantation in diamond using 30 keV Ga+ focused ion beam

Focused ion beam (FIB) technique is a well established technique for processing and modifying materials at micro- and nanoscale. FIB implantation with 30 keV Ga+ ions into a single crystal diamond has been studied via a combination of transmission electron microscopy (TEM) imaging and spectroscopy in the attempt to understand the damage formation in diamond. The damage formation has been studied as a function of implantation dose with eight different doses ranging from 6 × 1014 to 1 × 1016 ions/cm2. The TEM studies have revealed different structure of low-dose and high-dose implanted regions. 3.5 nm diamond cap layer was observed in the low-dose implanted layer. TEM analysis has shown volume extension of around 50% in the amorphous region and up to 7% in diamond at the crystal–amorphous interface. The density of amorphous damage layer was measured to be 2.51 g/cm3 and 2.24 g/cm3 in the low-dose and high-dose implanted regions, respectively. The amorphisation threshold for ion implantation in diamond at room temperature was determined to be 5.2 × 1022 vacancies/cm3.

► The evolution of the damage in diamond during 30 keV Ga implantation was studied.
► Implanted volume extends up to 7% in diamond and ~50% in the amorphised region.
► The degree of amorphous layer extension increased with ion fluence.
► The amorphisation threshold in diamond was found to be ~5 × 1022 vacancies/cm3.
► Thin 3.5 nm cap diamond layer was found near the specimen surface.