Microstructural and stress properties of ultrathin diamond-like carbon films during growth: Molecular dynamics simulations

The growth of ultrathin diamondlike carbon (DLC) films is modeled using molecular dynamics (MD) simulations with the reactive empirical bond order (REBO) potential. The microstructure and stress properties, such as film density, sp(3) hybridization fraction and internal stress, are carefully analyzed. A close correlation of the film structure and its properties is revealed. By varying the kinetic energy of the incident atoms, a strong energy dependence of the microstructure and stress is found. An optimal incident energy in the range of 30 - 150 eV should be reached to prepare homogeneous, continuous and compact DLC films. By studying the evolution of the film depth profile, the formation of intrinsic region is illustrated. A steady-state intrinsic region can be observed on condition that the film thickness exceeds a certain value, namely the minimum film thickness.