Temperature dependence of the formation of highly tetrahedral a-C:H

Abstract

Deposition from a low pressure plasma beam source creates a highly tetrahedral form of hydrogenated amorphous carbon (ta-C:H)) which is analogous to the ta-C formed by deposition from a filtered cathodic arc or mass-selected ion beam. The properties of ta-C:H have been studied as a function of the substrate deposition temperatureTs and ion energy using electron energy loss spectroscopy, X-ray diffraction and atomic force microscopy. The density decreases suddenly for deposition temperatures above a threshold value, which is found to decrease with increasing ion energy. The films above the threshold are mainly sp2 bonded, with graphitic layering and high roughness. The variation of the film density with the ion energy andTs is consistent with deposition occurring by subplantation.