The orientation dependence of Ni silicide phase formation in the silicidation of silicon nanowires (SiNWs) by Ni has been studied. SiNWs with a  growth direction contacted by Ni pads form θ -Ni2 Si for annealing conditions from 350 to 700 °C for 2 min. The θ -Ni2 Si has an epitaxial orientation of θ -Ni2 Si  Si [11 1-] and θ -Ni2 Si (100) Si (112) with the SiNW. On the other hand, SiNWs with a  growth direction react with Ni pads to form NiSi2 with an epitaxial orientation of NiSi2 [1 1- 0] Si [1 1- 0] and NiSi2 (111) Si (111) after annealing at 450 °C for 2 min. The  SiNWs were also silicided at 700 °C for 2 min, forming the low-resistivity NiSi phase. The epitaxial phases identified in the reactions of Ni films with SiNWs suggest that lattice matching at both the silicide/Si growth front and the surface of the original SiNW may play a significant role in determining the first silicide segment to grow.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)