Surface modification of single-crystalline diamond tool with high energy beam working

We investigated the reactivity of single-crystalline CVD diamond (100) surfaces milled using a Ga-focused ion beam (FIB) and modified by posttreatment (as-milled, vacuum heating, H2 plasma exposure) with Al, which is a standard work material for diamond tools, using an energy dispersive X-ray spectrometer. In the case of as-milled surfaces, residual Ga ions on surfaces heated in contact with Al decreased more rapidly than those heated without Al. The presence of Al, which could not be removed by NaOH etching, was confirmed on the surfaces heated at over 673 K in contact with Al for FIB with an acceleration voltage of 20 - 30 kV, and at 773 K for FIB acceleration at 10 kV. These results suggest that the tips of diamond tools formed by Ga FIB milling may adhere to Al workpieces at temperatures over 673 K if the surfaces are not modified by appropriate posttreatment. No Ga or Al was observed on surfaces that were modified by posttreatment consisting of vacuum heating at 1373 K for 1 h or H2 plasma exposure at 1200 K for 1 h even when heating at 573 K - 773 K in contact with Al, and thereafter etching was performed.