Formation of Nanofibers on the Surface of Diamond-Like Carbon Films by RF Oxygen Plasma Etching

Diamond-like carbon (DLC) nanosize fibers were formed by etching DLC films using RF O₂plasma. The DLC films were grown on silicon substrates by an RF plasma chemical vapor deposition (CVD) method, and a small amount of Ni was deposited on the DLC films using a DC magnetron sputtering method before the etching. DLC fibers of 20 nm diameter and 600 nm height were found on the etched surfaces of the DLC films. DLC fibers of similar size that were highly insulating were also obtained by O₂etching without the deposition of Ni. It was found that Al from the RF electrode was sputtered and contaminated the DLC surface during etching, which would have affected the formation of fibers. The anisotropic etching of DLC and the ion-induced growth of carbon fibers are discussed as the formation mechanisms of the DLC fibers. The DLC fibers bent and stuck together during a field-emission scanning electron microscope observation, especially in the slow scanning mode. Such soft fibers can exist vertically and straightly throughout the etching in RF plasma.