Ti-catalyzed Si nanowires by chemical vapor deposition: Microscopy and growth mechanisms

Si nanowires grow rapidly by chemical vapor deposition on Ti-containing isl ands on Si surfaces when an abundant supply of Si-containing gaseous precur sor is available. The density of wires is approximately the same as the den sity of the nucleating islands on the Si surface, although at least two dif ferent types of islands appear to correlate with very different wire growth rates. For the deposition conditions used, a minority of long, defect-free wires form, along with more numerous wires containing defects. Energy-disp ersive x-ray spectroscopy shows that the Ti-containing nanoparticles remain at the tip of the growing wires. The estimated diffusion coefficient of Si in TiSi2 is consistent with the catalyzing nanoparticle remaining in the s olid phase during nanowire growth. (C) 2001 American Institute of Physics.