GROWTH DYNAMICS OF FRACTAL GE CLUSTERS DURING CRYSTALLIZATION OF AMORPHOUS PHASE ON POLYCRYSTALLINE AU LAYER

The crystallization of amorphous Ge on a polycrystalline Au layer has been investigated by means of in situ transmission electron microscopy and scanning Auger microscopy. The polycrystalline Ge clusters showed a fractal morphology and their fractal dimensions decreased with increasing thickness of the Au underlayer. The growth size of the Ge clusters has been found to obey a power law. The results suggest that the growth is diffusion controlled by Ge atoms in a Ge-depleted zone surrounding a Ge cluster. The morphology has been well explained in terms of the diffusion length and the size of the Au crystallites in the Au underlayer.