Impact of thermal history of Si nanowire fabrication process on Ni silicidation rate

We have found that the thermal history of the fabrication process of Si nanowires (NWs) has a strong impact on the Ni silicidation rate. We compared the Ni silicidation rates in Si NWs fabricated by two different types of processes: the "Doping First" process, in which dopant activation annealing is completed before the lithography of NW structures, and the "Patterning First" process, in which NWs are firstly fabricated and then subjected to heat treatment entailing thermal oxidation and dopant activation. The Ni silicidation rate was appreciably higher in the Doping First process than in the Patterning First process. The difference is attributed to the residual stress rather than to the dopant concentration in Si-NWs. To control the silicidation rate in NWs, particular attention to the thermal history is necessary.