Atomic constraint in hydrogenated ‘‘diamond-like’’ carbon

Carbon bonding environments (measured by nuclear magnetic resonance spectroscopy) and compressive stress in plasma-deposited hydrogenated diamond-like carbon (DLC) films have been examined systematically as a function of substrate bias voltage. These results are related in terms of random network theory to show that hard DLC formed in an intermediate voltage range (100–400 V) consists of small graphitic clusters linked in a random network which is stiffened by a high density of quaternary carbon.