Focused Ion beam implantation of diamond

The interaction between diamond and a 30 kV Ga+ focused ion beam, has been studied. Electron backscattered diffraction identified the critical dose for amorphisation of the diamond surface at 2 × 1014 Ga+/cm2. Scanning transmission electron microscopy identified a 35 nm amorphous carbon layer which, at higher doses, can swell up to 31% its original volume and accommodate a significant quantity of gallium. Electron energy loss and energy dispersive X-ray spectroscopy further characterised this layer and identified both excess hydrogen and oxygen contained within a stable amorphous carbon structure.

► A diamond surface becomes amorphous after a 30 kV FIB dose of 2 × 1014 Ga+/cm2.
► The resulting 37 nm a-C layer swells up to 31% to contain the gallium.
► Excess hydrogen found in the a-C layer potentially stabilises the swollen lattice.