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Electronic and structural properties of titanium silicide nanostructures formed on Si (111) 7×7 reconstructed surface

R. STIUFIUC1,* , T. SOUBIRON1, B. GRANDIDIER1, D. DERESMES1

Affiliation

  1. Institut d’Electronique, Microélectronique et Nanotechnologie, IEMN, (CNRS, UMR 8520) Av. Poincaré, B.P.69, 59652 Villeneuve d’Ascq, France

Abstract

The formation of self-assembled titanium silicide nanostructures by reactive deposition of titanium on Si(111) 7×7 reconstructed surface at 800 °C, in ultrahigh vacuum (UHV) conditions, has been investigated by scanning tunneling microscopy (STM). The electronic properties of the same nanostructures have been studied using the scanning tunneling spectroscopy technique (STS) at 77 K in UHV conditions. In order to better understand the electronic properties of the nanostructures we have performed scanning tunneling spectroscopy (STS) measurements on both systems: the Si (111) 7x7 reconstructed surface and the TiSi nanostructures. From the topographic images we observed the formation of several types of titanium silicide nanostructures having different shapes and dimensions. We report here the successful formation of long and narrow structures which can be considered to be TiSi nanowires (NW) together with some island structures having a flat top region. Concerning the electronic transport properties, using our specific experimental set up, we evidenced the existence of an ohmic contact between all types of nanostructures and the silicon substrate in the 300 – 77 K temperature range. We explain this behavior using a model which takes into account the presence of silicon surface states bands at 77 K..

Keywords

Titanium silicide, Nanostructure, Self-assembling, Surface reconstruction.

Submitted at: Nov. 15, 2006
Accepted at: March 15, 2007

Citation

R. STIUFIUC, T. SOUBIRON, B. GRANDIDIER, D. DERESMES, Electronic and structural properties of titanium silicide nanostructures formed on Si (111) 7×7 reconstructed surface, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 3, pp. 591-594 (2007)