A comparative study of nickel silicides and nickel germanides: Phase formation and kinetics

Nickel silicides and nickel germanides are under interest for their microelectronic applications. They are often declared to have the same behavior that is usually observed in thin film reactions: sequential growth of some phases. This paper deals with the comparison of phase growth and kinetics in both systems. Our observations using several techniques show that nickel silicides have a sequential growth of Ni2Si, NiSi and NiSi2 as usually reported, whereas two nickel germanides, Ni5Ge3 and NiGe, grow simultaneously until the total consumption of Ni film. This switch from a sequential to a simultaneous growth is potentially important for the microelectronic industry. The kinetics parameters for the Ni rich phase growth (Ni2Si and Ni5Ge3) have been derived using a linear-parabolic law which takes into account both interfacial and diffusion contributions. The determination of these parameters helps to understand the contribution of interfacial phenomena on the thin film reaction.