Growth of nickel silicide (NiSix) nanowires by silane decomposition

Growth of single crystal nickel-silicide (NiSix) nanowires has been achieved on inert amorphous SiO2 and Si3N4 substrates covered with nanometer-size Ni particles. The CVD method was used to grow the nanowires by decomposition of silane at temperatures fully compatible with standard IC processing. Nanometer-size Ni particles were obtained by dissociation of a continuous 10 nm Ni film thin by an RTP (Rapid Thermal Process) step. Scanning Electron Microscopy (SEM) as well as Energy Backscattering Electron Diffraction (EBSD) techniques were used to characterize the as-synthesized nanowires. High-resolution transmission electron microscopy (HR-TEM) results show that the wires are monocrystalline with a separation of the lattice planes corresponding to Si or NiSix (the lattice mismatch between this two materials is only 0.4%). Finally, Energy Filtered Transmission Electron Microscopy (EF-TEM) analysis was used to determine that the composition of the grown nanowires was indeed NiSix. Our HR-TEM analysis also revealed that the silicide nanowires do not all grow in a specific growth direction but that several growth directions such as 111 or 110 are possible.