Effect of pulse width on deposition of diamond-like carbon on high-power pulsed magnetron sputtering

A diamond-like carbon (DLC) film was deposited using high-power pulsed magnetron sputtering. The effect of pulse width on the deposition of DLC film was investigated under constant peak power density or average power density to clarify the densification mechanism of DLC film. The maximum hardness of 25 GPa analyzed by nanoindentation was obtained using Ar gas without negative substrate bias voltage at pulse width 30 & mu;s and a peak power density of 1.5 kW cm(-2). The flux and energy of C+ and Ar+ incident to the DLC film was evaluated by using energy-resolved and time-resolved mass spectrometry to clarify the relation between the input power to the target and the behavior of produced ions. The change in hardness is well correlated with the ion flux ratio C+/Ar+. This result indicates that a flux and energy of Ar+ as well as C+ is a key parameter to characterize the microstructure of DLC film.