Surface hardness enhancement in ion-implanted amorphous carbon

Abstract

The feasibility of producing carbon nitride has been studied by ion implantation into amorphous carbon. Thin films were formed with 100 keV N+ or 80 keV C+ ions at various target temperatures and ion doses. The apparent surface hardness measured by nanoindentation with load-displacement data shows an optimum value of 22.3±0.4 GPa with the ion dose of 2×1017 N+/cm2 implanted at -100°C, while the hardness of the unimplanted amorphous carbon is 6.0±0.2 GPa. Self-implantation by carbon also produces similar hardness enhancement with a narrow temperature window. The maximum enhanced surface hardness is well correlated with the asymmetric diffuse peak at around 1500 cm-1 in Raman spectroscopy. © 1996 American Institute of Physics.