Maximized sp(3) bonding in carbon nitride phases

Carbon nitride films were deposited using a low pressure, dual ion beam sys tem consisting of a filtered cathodic vacuum arc and a plasma beam source f or carbon and nitrogen ions, respectively. This system maintains highly ion ized beams even at high nitrogen fluxes, unlike in single beam systems. Fil m composition and bonding were measured by electron energy loss spectroscop y. Films with nitrogen to carbon atom ratios (N/C) up to 0.5 are produced. The carbon bonding is found to change gradually from sp(3) to sp(2), rather than sharply above a critical N content, as found previously. This indicat es that N atoms form individual C=N bonds rather than causing a reversion o f the entire C network to sp(2). This allows us to maintain C sp(3) bonding to the highest N contents so far achieved. (C) 2000 American Institute of Physics. [S0003-6951(00)05336-5].