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Abstract: Transition-metal silicides have been used in the salicide process to form gate and source/drain contacts in MOSFET devices. How to control silicide formation in shallow junction devices and the kinetics of single silicide phase formation between the Si and metal thin films have received extensive attention and study. As the trend of miniaturization of Si devices moves from 45nm to smaller sizes, the formation of nanoscale metal silicides has attracted renewed interest in silicide formation. Nanostructures in Si nanowires have been studied for basic components in electronic and optoelectronics devices, especially for biosensors. Well-defined nanoscale building blocks such as ohmic contacts and gates on Si nanowires must be developed in order to be assembled into functional circuit components in future nanotechnology. It requires a systematic study of solid-state chemical reactions in the nanoscale to form these circuit components. In this review, we compare silicide formation in thin films and in nanowires and focus on the nucleation and growth of epitaxial silicides. The difference of silicide formation between the thin film case and the nanowire case, especially the kinetics of nucleation and growth, will be emphasized. [ABSTRACT FROM AUTHOR]

High quality single-crystalline NiSi2, Ni2Si and Ni31Si12 nanowire arrays coated with amorphous silicon dioxide were synthesized in high quantity by a nickel transport chemical vapor deposition (CVD) method. The morphological changes with various reaction temperatures, ambient pressures and reaction times, were observed and studied. At 750 °C and 850 °C, cone-shaped nanowire arrays were formed, composed of dense and oriented Ni31Si12 and Ni2Si nanowires with lengths of over 60 μm. The growth mechanisms of the nickel silicide nanowires have been proposed and identified with microscopy studies. Field emission measurements show that the as-grown NiSi2, Ni2Si and Ni31Si12 nanowires were of remarkable field enhancement factors, 2532, 4822 and 4099, respectively, and magnetic property measurements show ferromagnetic characteristics for the Ni2Si and Ni31Si12 nanowires, demonstrating promising potential applications for field emitters, magnetic storage, and biological cell separation. [ABSTRACT FROM AUTHOR]

Single-crystalline iron silicide nanowires were synthesized via an original approach, pre-deposition method (PDM), with significantly improved morphologies and physical characteristics as compared with those fabricated by conventional chemical vapor deposition. In the pre-deposition method, combining rapid thermal annealing (RTA) and chemical vapor deposition (CVD), iron silicide nanowires grew from the heterogeneous nucleation sites on the surface of the thin film without a catalyst or Al2O3 template. The morphology of the nanowires has been considerably improved in terms of alignment and aspect ratio. HRTEM analysis confirms that the nanowires were β-FeSi2 with a crystal direction of [111]. Physical property measurements indicate that compared with CVD β-FeSi2 nanowires, β-FeSi2 nanowires synthesized by the PDM performed better in both the field emission and magnetic properties. Magnetic property measurements show that the coercive field of PDM nanowires increased from 249 Oe to 900 Oe. Field emission studies reveal that the average β value of the CVD β-FeSi2 nanowires was 1060, while that of the PDM nanowires became 1892. Notably, with a furnace, few researchers can successfully synthesize nanowires of β-FeSi2, which is one of the most fascinating silicides for its important applications. [ABSTRACT FROM AUTHOR]