Linewidth related resistivities and growth behavior of nickel silicide nanowires by solid state reaction between Ni and electron-beam lithography prepared Si nanowires

Abstract

The linewidth related resistivity variation and growth behavior of nickel silicide nanowires by solid state reaction between Ni and Si nanowires are studied. 44 nm Ni is sputtered onto Si nanowires to form nickel silicide nanowires by rapid thermal annealing at 500°C, and the resistivities of formed nickel silicide nanowires are located in the range of 13.8-22.3 μΩ•cm for nanowires with linewidths larger than 80 nm (83-170 nm), while the resistivities rise to 39-125 μΩ•cm for the nanowires with linewidths of 30-80 nm. Multiple measurement results have shown that the resistivity increase is resulted from the formation of high resistivity Ni-rich phase (Ni3Si2 for nanowire with linewidth of 70 nm), which is closely related with the excessive Ni deposited on Si nanowire sidewalls. By using electron beam evaporation in place of sputter deposition, the Ni amount on the Si nanowire sidewalls has been reduced and the resistivities can be also in the range of 13.8-22.3 μΩ•cm for nanowires with linewidths of 45-80 nm. The length of nickel silicide nanowire shows square root dependence on annealing time, indicating a diffusion controlled growth with activation energy of 1.66 eV.