Nucleation during deposition of hydrocarbon ions as a function of substrate temperature

Abstract Hydrogenated carbon films were prepared from a highly ionized plasma beam source using acetylene. The films deposited at low temperatures have a very high sp 3 fraction, density, compressive stress and hardness. The sp 3 fraction, density and stress are found to fall sharply at about 530 K to values suggesting sp 2 bonding. The transition is believed to be associated with a change in mobility of carbon atoms in the surface area during the deposition process. At a higher temperature of about 700 K, the films possess a high nucleation density for diamond growth. X-ray diffraction and Raman spectra do not reveal diamond crystallites in these films, but further growth in an etching, hydrogen-rich plasma produces films which do show features of diamond.