TEM annealing study of normal grain growth in silver thin films

Normal grain growth in 80-nm-thick sputter-deposited Ag films was studied via in situ heating stage transmission electron microscopy. The as-deposited films with an initial grain size of 40–50 nm were held at a series of temperatures (one per specimen) below 250°C. A grain growth exponent n=3 from the law Dn−Don=k(T)t was calculated by minimizing the deviation in the fitting function to the experimental data. An activation energy for grain growth of 0.53 eV (53 kJ/mol) is found, which is close to surface diffusion. These findings are consistent with our previous work on abnormal grain growth in Ag: that grain growth in thin film nanocrystalline silver is dominated by surface diffusion mass transport.