Optical Band Gap of Diamond-Like Carbon Films as a Function of RF Substrate Bias

ABSTRACTDiamond-like carbon films have been deposited with a low temperature 2.45 GHz electron cyclotron resonance plasma enhanced chemical vapor deposition system. The bombarding ion energy was independently controlled with a RF bias to the substrate. The production rate of reactant species and the impinging ion energy are decoupled with this system. The optical band gap decreased from 2.7 to 1.2 eV as substrate bias was increased from 0 to -140 V.