Role of ripening and defects in the formation of mesotaxial cobalt-disilicide layers.

Previous studies of the formation of buried silicide layers through mesotaxy, i.e., the introduction of the metal component by ion implantation with subsequent annealing of the structure, have shown that high-quality films can be achieved, but at processing temperatures too high to be useful for integration with silicon device technology. Recently, we proposed a modified ripening model to describe the early stages of the formation of a buried film which intentionally excluded the role of defects. In the current study, the predictions of that model are tested by varying sample preparation conditions. We show that the shift of the silicide precipitate layer is correlated with the narrowing of the cobalt profile, thus requiring both processes to be described by the same mechanism. We also show in a TEM study that specific defect morphologies are correlated with specific properties of the forming buried film, requiring an extension of the previous model.