Influence of residual Ar+ in Ar cluster ion beam for DLC film formation

In order to study the influences of residual Ar monomer ion (Ar+) on sp2 content and hardness of diamond like carbon (DLC) films formed by Ar cluster ion beam assisted deposition, Ar cluster ion, Ar+ and their mixed ions (Ar cluster ion and Ar+) bombardments were performed during evaporation of C60. From near edge X-ray absorption fine structure (NEXAFS) and Raman spectroscopy measurements, lower sp2 content in the carbon films was obtained with Ar cluster ion bombardment than that with Ar+ and mixed ion. Furthermore higher hardness and smooth surface were shown with Ar cluster ion bombardments. Therefore it was important to reduce Ar+ in Ar cluster ion beams to obtain hard DLC films with flat surface