Investigation of focused ion beam induced damage in single crystal diamond tools

Highlights: • The FIB-induced damage layer should be paid enough attention when shaping the cutting edges of nanoscale diamond tools. • During FIB processing cutting tools made of natural single crystal diamond, the Ga⁺ collision will create a damage layer around tool tips. • The thicknesses of damaged layer and the level for amorphization of diamond significantly increase with beam energy. • The FIB-induced doping and defects during tool fabrication are responsible for the early detection of tool wear of nanoscale diamond tools. - Abstract: In this work, transmission electron microscope (TEM) measurements and molecular dynamics (MD) simulations were carried out to characterise the focused ion beam (FIB) induced damage layer in a single crystal diamond tool under different FIB processing voltages. The results obtained from the experiments and the simulations are in good agreement. The results indicate that during FIB processing cutting tools made of natural single crystal diamond, the energetic Ga⁺ collision will create an impulse-dependent damage layer at the irradiated surface. For the tested beam voltages in a typical FIB system (from 8 kV to 30 kV), the thicknesses of the damaged layers formed on a diamond tool surface increased from 11.5 nm to 27.6 nm. The dynamic damage process of FIB irradiation and ion–solid interactions physics leading to processing defects in FIB milling were emulated by MD simulations. The research findings from this study provide the in-depth understanding of the wear of nanoscale multi-tip diamond tools considering the FIB irradiation induced doping and defects during the tool fabrication process