Crystal grain nucleation in a-Si: a way to engineer the poly-Si morphology

The solid phase crystallization of chemical vapor deposited amorphous silicon films onto oxidized silicon wafers, induced by rapid thermal annealing has been extensively investigated The morphological evolution of the amorphous towards the polycrystalline Chase has been monitored by transmission electron microscopy analysis. The results have been interpreted in terms of a physical model containing few free parameters related to the thermodynamical properties of amorphous silicon and to the kinetical mechanisms of crystal grain growth at the early stages of transformation. On the basis of this model we have developed a computer simulation code which allows us to predict the final polycrystalline silicon morphology providing information on grain size distribution, average grain radius, and grain boundary length per unit area.