Characterization and mechanical properties of ion-implanted diamond surfaces

Single crystal diamond surfaces were treated by implantation of high energy nitrogen, chromium, and titanium ions. Ion energies were chosen between 60 and 180 keV and ion doses up to 1 X 10(17) ions/cm(2). The samples were he ated to temperatures If approximately 750 degreesC during implantation to p revent amorphization of the diamond crystal. The near-surface zone was char acterized by X-ray photoelectron spectroscopy. To reduce the amount of latt ice damage, some of the samples were coated with a sacrificial layer, e.g. 50 nm titanium, which was removed after ion implantation by dissolution in nitric acid. Mechanical properties of the implanted surfaces were tested un der atmosphere by abrading with a bronze wheel wetted with diamond suspensi on, Reactive properties were examined in an ultra-high vacuum by grinding w ith an iron wheel. It is shown that the wear of the zone influenced by chro mium implantation can be reduced significantly. This is explained by the pr esence of carbidic bonding combined with low damage of the diamond lattice. (C) 2001 Elsevier Science B.V. All rights reserved.