The nucleation and growth of isolated nickel disilicide precipitates in Ni-implanted amorphous Si thin films and the subsequent low-temperature silicide-mediated crystallization of Si was studied using in situ transmission electron microscopy. Analysis of the spatial distribution of the NiSi2 precipitates strongly suggested the occurrence of site saturation during nucleation. NiSi2 precipitates were observed in situ to migrate through the amorphous Si thin films leaving a trail of crystalline Si at temperatures as low as ∼484 °C. Initially, a thin region of epitaxial Si formed on {111} faces of the octahedral NiSi2 precipitates with a coherent interface which was shown by high-resolution electron microscopy to be Type A. Migration of the NiSi2 precipitates led to the growth of needles of Si which were parallel to 〈111〉 directions. The growth rate of the crystalline Si was limited by diffusion through the NiSi2 precipitates, and an effective diffusivity was determined at 507 and 660 °C. A mechanism for the enhanced growth rate of crystalline Si is proposed.

The silicide-mediated phase transformation of amorphous to crystalline silicon was observed in situ in the transmission electron microscope. Crystallization of nickel-implanted amorphous silicon occurred at ∼500 °C. Nickel disilicide precipitates were observed to migrate through an amorphous Si film leaving a trail of crystalline Si. Growth occurred parallel to 〈111〉 directions. High resolution electron microscopy revealed an epitaxial NiSi2/Si(111) interface which was Type A. A diffusion-controlled mechanism for the enhanced crystallization rate was determined.

The nucleation and growth kinetics of NiSi2 precipitation in amorphous silicon thin films ion implanted with nickel was investigated using scanning transmission electron microscopy. It was found that the nucleation rate could be approximately described by a delta function at time t = 0 when the films were annealed between 325 and 400 °C. The growth kinetics of the precipitates at these temperatures were described by r ∝ tn, where r was the average radius and n was about 1/3. This behavior is consistent with models for growth of three-dimensional particles in a two-dimensional diffusion field. It was also found that the implanted amorphous films displayed an enhanced rate of single crystal silicon formation, apparently catalyzed by migrating silicide precipitates.

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