Oxygen Ion Beam Etching of Diamond Like Carbon Films

Abstract

Effects of the oxygen ion beam etching of ion beam synthesized diamond like carbon (DLC) films were investigated in
present study. The etching rates as well as contact angle with water and surface morphology before and after the oxygen
ion beam treatment were studied. “Conventional” hydrogenated diamond like carbon (DLC) films were synthesized
from acetylene gas, while silicon and SiOx doped DLC films were deposited from hexamethyldisiloxane vapor and
acetylene gas mixture, and hexamethyldisiloxane vapor and hydrogen gas mixture respectively. In all cases ion beam
etching resulted in flat smooth surfaces. Etching rate of the “conventional” DLC films synthesized from acetylene and
DLC films deposited from hexamethyldisiloxane vapor and acetylene gas mixture was 44 nm/min and 29 nm/min
respectively. Thickness of the SiOx doped DLC film synthesized from hexamethyldisiloxane vapor and acetylene gas
mixture slightly increased as a result of the oxygen ion beam treatment. Contact angle with water of the DLC films
synthesized from acetylene after the ion beam etching remained the same. While contact angle of the diamond-like
carbon films deposited from hexamethyldisiloxane vapor and acetylene gas mixture decreased from 68° to 55°. Contact
angle with water of SiOx doped DLC films after the oxygen ion beam treatment was similar to the contact angle with
water of the silicon dioxide. Observed results were explained by different etching rates of the different carbon and
hydrocarbon fractures as well as by competition between two processes: ion beam etching and oxidation of the Si and
SiOx.