Atomic force microscopy study of the growth mechanisms of nanostructured sputtered Au film on Si(111): Evolution with film thickness and annealing time

Nanostructured Au films were deposited on Si(111) by room-temperature sputtering. By the atomic force microscopy technique we studied the evolution of the Au film morphology as a function of the film thickness h and annealing time t at 873 K. By the study of the evolution of the mean vertical and horizontal sizes of the islands forming the film and of their fraction of covered area as a function of h from 1.7 x 10(17) to 1.0 x 10(18) Au/cm(2) we identified four different growth stages such as: (1) 1.7 x 10(17) <= h <= 3.0 x 10(17) Au/cm(2), nucleation of nanometric three-dimensional (3D) hemispherical Au clusters; (2) 3.0 x 10(17) < h <= 5.2 x 10(17) Au/cm(2), lateral growth of the Au clusters; (3) 5.2 x 10(17) < h <= 7.7 x 10(17) Au/cm(2), coalescence of the Au clusters; (4 ) 7.7 x 10(17) < h <= 1.0 x 10(18) Au/cm(2), vertical growth of the coalesced Au clusters. The application of the dynamic scaling theory of growing interfaces allowed us to calculate the dynamic scaling exponent z = 3.8 +/- 0.3, the dynamic growth exponent beta = 0.38 +/- 0.03, the roughness exponent alpha = 1.4 +/- 0.1 and the Avrami exponent m = 0.79 +/- 0.02. Finally, the study of the evolution of the mean Au clusters size as a function of annealing time at 873 K allowed us to identify the thermal-induced self-organization mechanism in a surface diffusion limited ripening of 3D structures and also the surface diffusion coefficient of Au on Si (111) at 873 K was estimated in (8.2 x 10(-16)) perpendicular to (3 x 10(-17) ) m(2)/s. (C) 2010 American Institute of Physics. [doi:10.1063/1.3428467]