Production of NiSi phase by grain boundary diffusion induced solid state reaction between Ni2Si and Si(100) substrate

We report a process to obtain thin (5-20 nm thick) NiSi layers on Si(100) substrate from magnetron deposited Ni2Si thin films at low temperatures (180-200 degrees C). The time evolution of transformation was followed by means of Secondary Neutral Mass Spectrometry, transmission electron microscopy and resistance measurements. It is shown that there exist certain temperature-time and thickness-time windows inside of which the formation of NiSi takes place. The NiSi phase, formed along the grain boundaries of Ni2Si and grew by the motion of these interfaces, gradually consumes the Ni2Si phase. From the depth profiles of the first stage of the process, using the linear dependence of the average composition inside the film on the annealing time, the velocity of the grain boundary diffusion induced interface motion was also estimated. The normalized value of the resistance, proportional to the amount of the new phase, showed similar time evolution and yielded similar value for the interface velocity. (C) 2014 Elsevier B.V. All rights reserved.