Effects of Therma annealing on the atomic structure and the residual stress of amorphous carbon films: A molecular dynamics simulation

Changes of atomic structure and residual stress of tetrahedral amorphous carbon (ta-C) films were investigated by using a molecular dynamics simulation. Annealing of the ta-C film at 2000 K for 0.5 ns decreased the high level of residual stress of the ta-C film up to 27 %. On the contrary, the mechanical property of the films, which is represented by the sp(3) bond ratio, was seldom changed. Only a 1.7 % decrease in the sp(3) ratio was obtained, which agreed well with experiment. The annealing affected the relaxation of the atomic configuration with high energy, which is referred to as the high-stress configuration of the satellite peak found in the radial distribution function. Since a short-time annealing only reduced the residual stress, this method can be applied when one wants to reduce the residual stress which maintaining mechanical property.