Linear growth of Ni2Si thin film on n+/p junction at low temperature

Nickel mono-silicide has been considered a promising silicide candidate for sub-90 nm nodes of integrated circuits manufacturing. To form high-quality nickel mono-silicide as source/drain contact electrodes, a two-step low temperature rapid thermal process has been proposed, in which the as-deposited Ni will react with silicon during a low temperature (<310 °C) first anneal. Due to the lower annealing temperature Ni2Si will form after the first anneal. To better control the silicidation process the growth kinetics of Ni2Si thin film fabricated by solid-state reaction of sputtered Ni thin film on n+/p junction at low temperature is investigated in this paper. It is demonstrated that between 260 and 280 °C the thickness of Ni2Si thin film has a linear rather than parabolic dependence on annealing time. The corresponding activation energy for this linear growth is found to be ∼1.35 eV.