The surface topography, structural and mechanical properties of Ge1 − xCx films prepared by magnetron co-sputtering

Non-hydrogenated germanium carbide (Ge1 − xCx) films were prepared by magnetron co-sputtering method in a discharge of Ar. The surface topography, chemical bonding configurations and hardness were characterized by means of atomic force microscopy, X-ray photoelectron spectroscopy (XPS) and nanoindentation technique. The substrate temperature (Ts) exhibited important influence on the film surface topography. With the increase of Ts, the films became smoother owing to stronger diffusion. The film mass density varied between 4.40 g/cm3 and 4.47 g/cm3 depending on Ts. A progressive densification of the film microstructure occurred with Ts increasing. The XPS results showed that both the content of the GeGe bond and the content of the CGe bond in the films increased as Ts increased. The relationship between the chemical bonding and the mechanical properties of the Ge1 − xCx films was also explored. It showed that the hardness of the films increases from 7.47 GPa to 11.48 GPa as Ts increases from 200 °C to 700 °C. Therefore, increasing the substrate temperature led to a more dense and hard Ge1 − xCx film.