Annealing effects in Ag-doped amorphous carbon films deposited by dc magnetron sputtering

Thin carbon films containing about 11 at.% Ag were deposited by dc magnetron sputtering of composite graphite/silver target. The stability of film microstructure upon annealing at 600 °C in a vacuum has been studied by transmission electron microscopy and electron diffraction. The as-deposited C/Ag films consisted of silver nanoparticles distributed in an amorphous carbon matrix. Upon annealing, the tendency was revealed towards coalescence within the set of particles, i.e. increase in the particle average diameter and decrease in the density of particles with time. The above changes occurred faster than it is predicted by the theories for three-dimensional and two-dimensional diffusion coalescence. The direct collisions and fusion of particles along with the diffusion transport of Ag atoms is suggested to cause the above effect.