A scanning tunnelling microscopic study was made of the effects of thermal annealing upon the surface morphology of 80nm-thick films. The films were thermally evaporated onto glass substrates, and were then measured (via scanning tunnelling microscopy) at room temperature; before and after annealing. The annealing was performed at temperatures of between 200 and 500C, for periods ranging from 1 to 60h. The evolution of the average surface grain-size, and the root mean square roughness amplitude of the films, were monitored as a function of annealing temperature and time. The data suggested that surface diffusion was the main process which operated at annealing temperatures of 300C and below. The activation energy for the surface self-diffusion of Au was of the order of 1.1eV. Other mechanisms appeared to predominate at higher temperatures.

D.Porath, E.Bar-Sadeh, M.Wolovelsky, A.Grayevsky, Y.Goldstein, O.Millo: Journal of Vacuum Science and Technology A, 1995, 13[3], 1165-70