Study on Failure Process of Silicon-Doped Amorphous Carbon by ReaxFF Molecular Dynamics Simulation for HAMR

The failure process of silicon-doped amorphous carbon (a-C:Si) films for heat-assisted magnetic recording (HAMR) disk is studied by reactive force field molecular dynamics (ReaxFF MD) simulations. Insights on the failure process of a-C:Si film are provided by analyzing system potential energy, amount of consumed oxygen molecules, film structure, number of carbon-oxygen bonds and silicon-oxygen bonds, atomic shear strain, radial distribution function, and density. The a-C:Si film graphitizes initially, and then it begins to combust accompanying by delamination of surface oxide layers with the increase in temperature. The mechanism of atomic oxygen diffuses in the film is proposed. The a-C:Si film shows a good thermal stability below 1500 K. It can act as carbon overcoat of HAMR disk.