Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 36: Postersitzung (Elektronische Struktur, Grenzfl
äche fest-flüssig, Halbleiteroberfl
ächen und -grenzfl
ächen, Nanostrukturen, Oberfl
ächenreaktionen, Teilchen und Cluster, Struktur und Dynamik reiner Oberfl
ächen)
O 36.41: Poster
Montag, 7. März 2005, 15:00–18:00, Poster TU F
Titanium silicide contacts for nanoengineering — •Svend Vagt, Gernot Gardinowski, Tammo Block, Volkmar Zielasek, and Herbert Pfnür — Institut für Festkörperphysik, Abteilung Oberflächen, Universität Hannover, Appelstr.2, 30167 Hannover, Germany
For the electrical characterization of nanostructures it is vital to connect the mesoscopic to the macroscopic world. The requirements for such contacts are chemical purity, well defined boundaries, and a substrate free of defects for further nanoprocessing.
TiSi2 contacts with a variable separation down to 200nm have been generated by an optimized e-beam lithography process and were studied with SEM, STM, and µ-Auger. Ti was evaporated 50 nm thick on a lithographically structured Si substrate and subsequently annealed to activate the silicide formation at the Si interface. These contacts have been demonstrated to be stable up to 1200K on Si(100) and Si(111). STM measurements reveal atomically clean Si surfaces in the contact gaps and sharp and well-defined contact boundaries.
When the Ti pads are capped by a Si layer prior to thermal silicide formation, step bunching of the substrate due to lattice-mismatch induced strain close to the contact boundaries is reduced, probably because of a reduced consumption of substrate silicon.
Futher analysis focusses on even thinner TiSi2 contacts to improve the connectability between the contacts pads and the nanostructures.