We report here the first successful growth of large-area, low-resistivity cobalt disilicide (CoSi(2)) nanodot arrays on epitaxial (0 0 1)Si(0.7)Ge(0.3) substrates by using the nanosphere lithography (NSL) technique with all interposing amorphous Si (a-Si) thin film serving as the sacrificial layer. For the Co/a-Si bilayer nanodots array on Si(0.7)Ge(0.3) samples after annealing, polycrystalline CoSi(2) appears to form as the only silicide phase at an annealing temperature as low as 500 degrees C The a-Si interlayer with appropriate thickness was found to effectively prevent Ge segregation and maintain the morphological stability in forming CoSi(2) nanodots on Si(0.7)Ge(0.3) substrate. The size, interparticle spacing, and triangular shape of the CoSi(2) nanodots remain almost unchanged even after annealing at 950 degrees C. For the Co/a-Si nanodot samples further annealed at 1000 degrees C, amorphous SiO(x) nanowires, 15-35 nm in diameter, were observed to grow from CoSi(2) nanodot regions. The observed results present the exciting prospect that the NSL technique in conjunction with a sacrificial a-Si interlayer process promises to be applicable in fabricating periodic arrays of other low-resistivity silicide nanocontacts with controlled size, shape, and periodicity on Si(1-x)Ge(x), substrates. (C) 2011 Elsevier B.V. All rights reserved.
