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. © 1990, Materials Research Society. All rights reserved.