Kinetics of NiSi-to-NiSi2 transformation and morphological evolution in nickel silicide thin films on Si(0 0 1)

We have investigated the kinetics of the NiSi-to-NiSi2 transformation by monitoring the phases present in nickel silicide films after various annealing treatments. It has been found that, for very short annealing times, essentially pure NiSi films can be retained on Si(0 0 1) at temperatures up to 800 °C, a temperature significantly higher than that normally observed (∼700 °C) for the NiSi-to-NiSi2 transformation. A time–temperature transformation diagram was constructed to elucidate the kinetics of the NiSi-to-NiSi2 transformation, which was explained in terms of the classical theories of nucleation and growth. It was also found that, at a given temperature, agglomeration of NiSi films can be avoided by using short annealing times. The activation energy for grain growth in NiSi films was estimated using a concept of “agglomeration time”.