Molecular dynamics study of reversible relaxation of compressive mechanical stress in polycrystalline metal films after the interruption of their deposition

The results of MD simulation of polycrystalline metal films deposition are presented. Using Cr and Cu as an example, the influence of the deposited particle energy, the deposition rate, as well as the film material and temperature on the change in stress upon interruption and resuming deposition is studied. The simulation results showed that the reversible relaxation of compressive stress in polycrystalline films upon interruption of deposition is associated with the lateral displacement of atoms trapped in grain boundaries from the surface during deposition. This process of redistribution of atoms in grain boundaries leads to their more compact arrangement and proceeds in the same way in all layers of the film, both after and during deposition. The higher the mobility of atoms on the surface due to the type of material, temperature or energy of the deposited particles and the higher the rate of deposition, the greater the change in stress when it stops. No escape of atoms from grain boundaries back to the film surface was observed when deposition was interrupted.