Comparison of the agglomeration behavior of Au and Cu films sputter deposited on silicon dioxide

The agglomeration behavior of Cu and Au films each with a thickness of 5 and 50 nm, deposited on thermally grown SiO2 by dc magnetron sputtering, was investigated with scanning electron microscopy. The size of Cu islands formed by agglomeration increased with increasing annealing temperature. Also, the agglomeration of Cu films seem to follow the grain boundary grooving process. On the other hand, Au islands have an identical size at different annealing temperatures. Au films were observed to agglomerate via nucleation of voids followed by the fractal growth of voids. The fractal dimension was determined to be 1.7 indicating that the fractal growth of voids can be described with a diffusion limited aggregation model. Finally, the kinetics of agglomeration of the Au films was described with an Avrami-type equation. (C) 2003 American Institute of Physics.