Modeling of the depletion of the amorphous-silicon surface during hemispherical grained silicon formation

A model, based on surface energy minimization under nonequilibrium conditions, is presented to describe the evolution of the amorphous silicon (a-Si) topography near the hemispherical grained silicon. The evolution of the depletion area can be explained by a combination between capture of silicon (Si) atoms at the grain boundary and energy minimization of the surrounding a-Si surface. Grain depletion dependence on annealing time was measured by means of transmission electron microscopy. The simulated results agree well with the real observations. This approach is presented as a first step in physically based modeling of HSG formation.