Nitrogen implantation into amorphous carbon films: XPS, AES and Raman analyses

Abstract

Hard amorphous hydrogenated carbon films (350 nm thick) deposited by self-bias glow discharge were implanted at room temperature with 70 keV nitrogen ions at fluences of 0.6, 1.0 and 2.0 × 10 17 N/cm 2. The implanted energy was chosen so that the projected range plus straggling ( R p + ΔR p) was smaller than the film thickness. The implanted samples were analyzed by Auger electron spectroscopy, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. Factor analysis was applied to the crater-edge Auger profile. For micro-Raman depth profiles, a well focused argon laser beam was scanned across the wall of the same crater produced by 2 keV Ar + bombardment for the AES measurements. XPS depth profiles were also obtained. The Auger and Raman results indicated that the structural modifications (increase of the relative amount of carbon sp 2-bonds) are related to the energy deposited by the incident ion and depend on the ion fluence. Nitrogen incorporation into the amorphous carbon network can be inferred from XPS results.