Morphology determined by nucleation

In addition to forming surfaces based on equilibrium energy relationships, nonequilibrium shapes may be determined by the process of nucleation and growth of the material. The nucleation process described in Section 10.6 leads to small islands on the surface. With sufficient atomic mobility these may have surface facets 

The most common observation of all is when the film cannot make any satisfactory alignment with the substrate and therefore effectively ignores it. This is also the case for deposition of a thin film on an amorphous substrate. In such a situation the film typically chooses to put its atoms as close together as possible to maximize bonding among them. This leads to a strong preference for nucleation of grains with a surface 

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