Inhomogeneous structure in hydrogenated tetrahedral amorphous carbon thin films

Abstract

The structure of hydrogenated tetrahedral amorphous carbon (ta-C:H) thin film was investigated by observing variations in film stress and mass density as a function of the film thickness. Cross-sectional transmission electron microscopy clearly shows an inhomogeneous microstructure that includes a region near the substrate/film interface with a higher density than the remainder of the film. It is postulated that surface charge accumulation of the insulating coating reduces the energy of the incoming ions. Lower-energy ion bombardment results in a ta-C:H film with both reduced stress and mass density. {copyright} {ital 1999} {ital The American Physical Society}